MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'International Journal of Imaging Systems and Technology' source. Mon, 30 Jan 2012 06:30:02 +0100 http://www.medworm.com/index.php?rid=5412641&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20300 AbstractAn edge preserving filter algorithm of side scan sonar (SSS) image based on wavelet modulus maxima shift‐correlative (WMMS) technique is proposed in this article. First, the proposed WMMS algorithm decomposes SSS image into multiscale wavelet coefficients. Then the modulus maxima, which are produced by catastrophe points, are extracted from wavelet coefficients. The algorithm matches these maxima across the different scales to identify signal or noise. After correcting the “drifting” phenomenon of modulus maxima, a correlation factor array of wavelet coefficients is constructed by strengthening the maxima dominated by signal and suppressing those maxima dominated by noise. By correlating wavelet coefficients with the correlation factor array, the WMMS strengthens the useful h... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5412641 Thu, 17 Nov 2011 11:13:18 +0100 5412641 http://www.medworm.com/index.php?rid=5412640&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20299 AbstractIn this article, several advanced connected transformations from mathematical morphology for computational neuroanatomy applications are developed. In particular, brain is separated from the skull in MRI T1 using morphological connected openings. The use of connected transformations allow the preservation of regions, without introduce new information. As a result, the segmented brains preserve by complete information of the original images being more reliable for the specialist who deals with information such as white and gray matter. © 2011 Wiley Periodicals, Inc. Int J ImagingSyst Technol, 21, 336–348, 2011 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5412640 Thu, 17 Nov 2011 11:13:17 +0100 5412640 http://www.medworm.com/index.php?rid=5412639&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20298 This article proposes the new splitting–shooting method, new splitting integrating method, and their combination. These methods approximate results show that the true errors of pixel intensity are O(H), where H is the pixel size. Note that the algorithms in this article do not produce any sequential errors as N ≥ N0, where N0 (≥2) is an integer independent of N and H. This is a distinctive feature compared to our previous papers on this subject. The other distinct feature of this article is that the true error bound O(H) is well suited to images with all kinds of discontinuous intensity, including scattered pixels. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 323–335, 2011 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5412639 Thu, 17 Nov 2011 11:13:16 +0100 5412639 http://www.medworm.com/index.php?rid=5412638&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20297 AbstractThe stimulation paradigms of a functional MRI (fMRI) usually consist of one or more stimulations and a resting state in the block‐based and event‐related designs. To localize the activation areas in the human brain, each voxel is statistically analyzed using the fMRI data measured with the stimulation. The conventional method can be inefficient for experiments with multiple stimuli because of measuring the resting‐state signals repeatedly, causing redundancy in the scanning process. Although the phase mapping method can be applied to reduce the redundant resting‐state measurements, there are still limitations in the detection of regions activated by multiple stimuli and the periodic sequence of the multiple stimuli. In this article, a new fMRI data analysis method is presen... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5412638 Thu, 17 Nov 2011 11:13:15 +0100 5412638 http://www.medworm.com/index.php?rid=5412637&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20296 AbstractTractography is one of the most important applications of diffusion tensor imaging (DTI) which noninvasively reconstructs 3D trajectories of the white matter tracts. Because of the intravoxel orientation heterogeneity of DTI data, some of tractography algorithms are unable to follow the correct pathways after the crossing and branching regions. Front propagation techniques are efficient methods in tracking the crossing fibers. A key parameter influencing the performance of these algorithms is the cost function which is mainly based on the colinearity of tensors' eigenvectors. The effect of the eigenvalues on the anisotropy strength of tensor has not been previously addressed in the definition of the speed function. In this article, a new speed function, based on the effect of diffu... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5412637 Thu, 17 Nov 2011 11:13:13 +0100 5412637 http://www.medworm.com/index.php?rid=5150076&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20263 AbstractContent based image retrieval (CBIR) is used to retrieve digital images from large databases. However, the problem of retrieving images on the basis of the contents remains largely unsolved. The proposed method of image retrieval is based on the information provided by histogram analysis of the intensity or grayscale values of images. Some additional properties are also calculated and used that are based on regional characteristics of various objects in the image. The need to retrieve the additional regional properties arises due to the fact that the standard histograms are insensitive to small changes in images. Many images of different types can have similar histograms, because, histograms provide only a coarse characterization of an image. This is the main disadvantage of using ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5150076 Wed, 24 Aug 2011 21:55:50 +0100 5150076 http://www.medworm.com/index.php?rid=5150075&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20294 AbstractTo develop a method for segmenting cerebrospinal fluid (CSF) regions with complex, inhomogeneous pulsatile patterns in phase contrast magnetic resonance imaging (PC‐MRI) sequences. Our approach used various temporal features of flow behavior as input attributes in an unsupervised k‐means classification algorithm. CSF flow parameters for the cervical subarachnoid spaces and the pontine cistern were calculated in 26 healthy volunteers. Background and aliasing corrections were applied automatically. The algorithm's reproducibility was determined by calculating two parameters (area and stroke volume) while varying the initially selected seed point. The influence of background correction on these parameters was also assessed. The method was highly reproducible, with coefficients of ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5150075 Wed, 24 Aug 2011 21:55:50 +0100 5150075 http://www.medworm.com/index.php?rid=5150074&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20295 AbstractImage processing requires an excellent image contrast‐enhancement technique to extract useful information invisible to the human or machine vision. Because of the histogram flattening, the widely used conventional histogram equalization image‐enhancing technique suffers from severe brightness changes, rendering it undesirable. Hence, we introduce a contrast‐enhancement dynamic histogram‐equalization algorithm method that generates better output image by preserving the input mean brightness without introducing the unfavorable side effects of checkerboard effect, artefacts, and washed‐out appearance. The first procedure of this technique is; normalizing input histogram and followed by smoothing process. Then, the break point detection process is done to divide the histogram... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5150074 Wed, 24 Aug 2011 21:55:49 +0100 5150074 http://www.medworm.com/index.php?rid=5150073&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20292 AbstractA calibration method for diffusion‐weighted imaging using an isotropic phantom is proposed. The key point of the method consists in finding optimized balancing times for different orientations of diffusion‐encoding gradients followed by retrospective rescaling of the diffusion‐weighted images. The correction protocol was applied to produce improved fractional anisotropy maps which were analyzed with statistical histograms. The results demonstrate that the described scheme of systematic error reduction is a valid approach for quality control studies of gradient system performance for diffusion‐weighted imaging. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 271–279, 2011; (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5150073 Wed, 24 Aug 2011 21:55:48 +0100 5150073 http://www.medworm.com/index.php?rid=5150072&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20293 We present an iterative scheme for adaptive smoothing of functional magnetic resonance images. We propose a novel similarity measure to estimate the weights of the smoothing filter based on the functional similarity of the voxels under the smoothing kernel with the voxel under consideration as well as their similarity with a reference time‐course representing the expected BOLD response. We demonstrate the performance of the proposed method by applying the method to preprocess both simulated and real fMRI data. The method improves the functional SNR of the data while preserving the shapes of the functionally active region and its performance is not compromised when structured noise is the dominant noise source. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 260‐270, 201... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5150072 Wed, 24 Aug 2011 21:55:47 +0100 5150072 http://www.medworm.com/index.php?rid=5150071&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20291 AbstractParkinson's disease (PD) is a neurodegenerative disorder resulting from the progressive loss of dopaminergic (DA) neurons in the substantia nigra (SN). In our previous study, attempts were made to directly visualize the SN and quantify the differences in shapes and boundaries of the SN between PD subjects and comparison to the normal control subjects using two‐dimensional T2*‐weighted 7.0‐T MRI images (Cho et al., Mov Disord, accepted for publication). However, a two‐dimensional analysis does not represent the entire SN. Therefore, to overcome the limitation of 2D analysis, we acquire 3D image of the SN. For this study, we scanned nine PD patients, along with nine age‐matched control subjects, using a research prototype 7.0‐T MRI scanner in an attempt to visualize the 3... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5150071 Wed, 24 Aug 2011 21:55:46 +0100 5150071 http://www.medworm.com/index.php?rid=5150070&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20290 AbstractDescribed herein are the advantages of using sub‐sinograms for single photon emission computed tomography image reconstruction. A sub‐sinogram is a sinogram acquired with an entire data acquisition protocol, but in a fraction of the total acquisition time. A total‐sinogram is the summation of all sub‐sinograms. Images can be reconstructed from the total‐sinogram or from sub‐sinograms and then be summed to produce the final image. For a linear reconstruction method such as the filtered backprojection algorithm, there is no advantage of using sub‐sinograms. However, for nonlinear methods such as the maximum likelihood (ML) expectation maximization algorithm, the use of sub‐sinograms can produce better results. The ML estimator is a random variable, and one ML reconstr... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5150070 Wed, 24 Aug 2011 21:55:46 +0100 5150070 http://www.medworm.com/index.php?rid=5150069&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20274 This article presents a method for depth estimation using image focus based on the linear regression model. Two datasets are selected for each pixel based on the maximum value which is calculated using Laplacian operator. Then linear regression model is used to find lines that approximate these datasets. The best fit lines are found using least squares method. After approximating the two lines, their intersection point is calculated, and weights are assigned to calculate the new value for the depth map. The proposed method is compared with four depth estimation algorithms. Six different objects are selected for testing the proposed method. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 241–246, 2011; (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=5150069 Wed, 24 Aug 2011 21:55:45 +0100 5150069 http://www.medworm.com/index.php?rid=4808733&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20284 AbstractRegional modulation of the level of cortical neurotransmitters in the brain would serve as a new functional brain mapping technique to interrogate the neurochemical actions of the brain. We investigated the utility of the application of low‐intensity, pulsed sonication of focused ultrasound (FUS) to the brain to modulate the extracellular level of dopamine (DA) and serotonin (5‐HT). FUS was delivered to the thalamic areas of rats, and extracellular DA and 5‐HT were sampled from the frontal lobe using the microdialysis technique. The concentration changes of the sampled DA and 5‐HT were measured through high‐performance liquid chromatography. We observed a significant increase of the extracellular concentrations of DA and 5‐HT in the FUS‐treated group as compared with ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808733 Wed, 11 May 2011 23:37:09 +0100 4808733 http://www.medworm.com/index.php?rid=4808732&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20286 AbstractIndependent component analysis (ICA) is a popular method for the analysis of functional magnetic resonance imaging (fMRI) signals that is capable of revealing connected brain systems of functional significance. To be computationally tractable, estimating the independent components (ICs) inevitably requires one or more dimension reduction steps. Whereas most algorithms perform such reductions in the time domain, the input data are much more extensive in the spatial domain, and there is broad consensus that the brain obeys rules of localization of function into regions that are smaller in number than the number of voxels in a brain image. These functional units apparently reorganize dynamically into networks under different task conditions. Here we develop a new approach to ICA, prod... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808732 Wed, 11 May 2011 23:37:08 +0100 4808732 http://www.medworm.com/index.php?rid=4808731&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20276 This article describes the novel application of a non‐negative matrix factorization (NMF) algorithm to the decomposition of the magnitude spectra of fMRI time‐series into distinct spectral components. From the fMRI data of healthy volunteers during the resting state, the frequency‐specific components were decomposed into five basis functions. Group analysis revealed five different spatial patterns associated with these basis functions, in which each of the spatial patterns may correspond to a distinct spectrally coherent RSN. The RSN with the lowest center frequency showed a similar spatial pattern to the “default‐mode” network, which involves the medial superior and middle frontal cortex along with the posterior cingulate cortex. On the other hand, RSNs with higher frequencies... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808731 Wed, 11 May 2011 23:37:07 +0100 4808731 http://www.medworm.com/index.php?rid=4808730&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20278 AbstractThe ability to detect where a person is attending is fundamental for brain‐computer‐interfaces. We explore how the attentional focus can be decoded from brain signals noninvasively acquired with functional magnetic resonance imaging (fMRI). Several cortical regions have previously been reported to have topographic maps reflecting the focus of visual attention. Interestingly, attentional maps were observed to be gradually less topographic when moving from early visual areas toward extra‐occipital areas. Recent studies suggested that this might indicate a shift from topographically represented local processing to a global processing dominated by laterality. However, it remains unclear, to which extent the topographical representation of a region characterizes its quality to enc... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808730 Wed, 11 May 2011 23:37:06 +0100 4808730 http://www.medworm.com/index.php?rid=4808729&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20277 AbstractAutomated white matter hyperintensity (WMH) segmentation on magnetic resonance imaging is greatly advantageous for various clinical studies using large‐sample data. Accurate localization of WMH can provide more beneficial information for clinical studies, as differences of regional WMH existence may be linked to clinical symptoms. We suggest a fully automated method for WMH quantification and localization without human interaction using T1‐weighted and fluid‐attenuated inversion‐recovery (FLAIR) images. The known sources of false‐positive results in the subarachnoid space and brain‐cerebrospinal fluid (CSF) interface were removed by applying a WMH candidate‐region mask. WMH segmentation was performed based on the Markov random field model. The intensity‐substitution... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808729 Wed, 11 May 2011 23:37:06 +0100 4808729 http://www.medworm.com/index.php?rid=4808728&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20279 AbstractIn this article, a novel approach to schizophrenia classification using magnetic resonance images (MRI) is proposed. The presented method is based on dissimilarity‐based classification techniques applied to morphological MRIs and diffusion‐weighted images (DWI). Instead of working with features directly, pairwise dissimilarities between expert delineated regions of interest (ROIs) are considered as representations based on which learning and classification can be performed. Experiments are carried out on a set of 59 patients and 55 controls and several pairwise dissimilarity measurements are analyzed. We demonstrate that significant improvements can be obtained when combining over different ROIs and different dissimilarity measures. We show that combining ROIs using the dissimi... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808728 Wed, 11 May 2011 23:37:05 +0100 4808728 http://www.medworm.com/index.php?rid=4808727&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20280 AbstractOne of the many advantages of multivariate pattern recognition approaches over conventional mass‐univariate group analysis using voxel‐wise statistical tests is their potential to provide highly sensitive and specific markers of diseases on an individual basis. However, a vast majority of imaging problems addressed by pattern recognition are viewed from the perspective of a two‐class classification. In this article, we provide a summary of selected works that propose solutions to biomedical problems where the widely‐accepted classification paradigm is not appropriate. These pattern recognition approaches address common challenges in many imaging studies: high heterogeneity of populations and continuous progression of diseases. We focus on diseases associated with aging and ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808727 Wed, 11 May 2011 23:37:04 +0100 4808727 http://www.medworm.com/index.php?rid=4808726&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20287 AbstractRecent studies showed that the local field potential (LFP) in motor cortex carries information about parameters of limb movements and could be used as a candidate neural signal in brain‐machine interfaces to control external devices. However, it is yet to be clear how much information LFP can offer and how it can be effectively used in BMIs. In this article, we systematically evaluated the decoding performance of combining LFP and single‐unit activity (SUA) from the primary motor cortex of rats performing the lever‐pressing task. The results showed that the decoding power could be significantly improved by combining SUA and LFP in the time‐frequency mode, which is based on the separation of LFP into multiple frequency bands. Furthermore, we found that using all frequency ba... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808726 Wed, 11 May 2011 23:37:04 +0100 4808726 http://www.medworm.com/index.php?rid=4808725&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20281 AbstractPrevious decoding algorithms used in brain machine interfaces (BMIs) usually seek a static functional mapping between the spatio‐temporal neural activity and behavior and assume that the neural spike statistics do not change over time. However, recent work indicates the significant variance in neural activities, which suggests the nonfeasibility of the stationary assumptions on the neural signal sequences. To track the time‐changing neural activity during the nonlinear decoding process, we developed a time‐varying approach based on general regression neural network (GRNN) with a dynamic pattern layer. Applied on both simulated neural activity and in vivo BMI data extracted from rat's motor cortex, the proposed method reconstructs the movement signals better than the original ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808725 Wed, 11 May 2011 23:37:02 +0100 4808725 http://www.medworm.com/index.php?rid=4808724&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20285 This article addresses the issue of learning efficient linear spatial filters and a classification function to match noninvasive electroencephalographic (EEG) signals to motor imagery tasks voluntarily performed by the subjects. The new perspective used in this article consists in releasing the widely accepted hypothesis stating that motor tasks‐related brain activities should have similar time course across trials. This work proposes a learning model that takes into account two previously unconsidered sources of variability. First, the time course of the subject's brain activity, while performing a motor imagery task, will be considered as a trial‐dependent variable. This means that the optimal time, defined as an amount of time after the trial cue, chosen to determine the task perfor... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808724 Wed, 11 May 2011 23:37:02 +0100 4808724 http://www.medworm.com/index.php?rid=4808723&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20288 In this study, we used several m‐sequences instead of one with the intent of increasing the number of possible command options in a BCI setting. We also tested two different classifiers to decide between the m‐sequences and study the performance of multi channel classifiers versus single channel classifiers. The study is done over two different flickering frequencies, 15 and 30 Hz to investigate the effect of flickering frequency on the accuracy of the classification methods. Our study shows that the EEG channels are correlated, and although all the channels contain some useful information, but combining them with a multi channel classifier based on the assumption of having conditional independence will not improve the classification accuracy. In addition, we were able to get reasonabl... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808723 Wed, 11 May 2011 23:37:01 +0100 4808723 http://www.medworm.com/index.php?rid=4808722&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20282 AbstractWe propose a hierarchical stimulus presentation paradigm for a P300‐based Hangul (Korean script) input system. A P300‐based input system (or speller) is one of the most promising noninvasive brain‐computer interface (BCI) applications based on its direct applicability in many computer programs. Although the previous row/column stimulus presentation paradigm has been well‐suited to the English input, it may not be optimal for a Hangul input because Hangul has a distinct hierarchical structure. To overcome the limitation of the previous paradigms, we developed a new P300‐based Hangul input system by taking the unique hierarchical structure of Hangul into account for creating a hierarchical stimulus presentation paradigm. By using the hierarchical structure, we can effective... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808722 Wed, 11 May 2011 23:37:00 +0100 4808722 http://www.medworm.com/index.php?rid=4808721&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20283 AbstractEEG‐based discrimination among motor imagery states has been widely studied for brain‐computer interfaces (BCIs) due to the great potential for real‐life applications. However, in terms of designing a motor imagery‐based BCI system, a lot of research in the literature either uses a frequency band of interest selected manually based on the visual analysis of EEG data or is set to a general broad band, causing performance degradation in classification. In this article, we propose a novel method of selecting subject and class specific frequency bands based on the analysis of a channel‐frequency matrix, which we call a channel‐frequency map. We operate the classification process for each frequency band individually, i.e., spatial filtering, feature extraction, and classific... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808721 Wed, 11 May 2011 23:36:59 +0100 4808721 http://www.medworm.com/index.php?rid=4808720&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20289 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4808720 Wed, 11 May 2011 23:36:59 +0100 4808720 http://www.medworm.com/index.php?rid=4572532&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20266 AbstractA combinatorial algorithm to compute an orthogonal convex skull of a digital object imposed on the background grid is presented in this paper. The proposed algorithm has the time complexity of O(n log n), which improves the earlier method of O(n2) time complexity for finding the convex skull of a simple orthogonal polygon. A set of rules is formulated first and then an orthogonal convex skull is derived by applying these rules while traversing along the boundary of the inner orthogonal polygon that tightly inscribes the given digital object. The algorithm uses only comparison and addition in the integer domain, which makes it amenable to fast real‐world applications. Experimental results on different shapes have also been presented to demonstrate the efficacy and elegance of the ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4572532 Tue, 01 Mar 2011 00:00:00 +0100 4572532 http://www.medworm.com/index.php?rid=4486235&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20273 This article presents an adaptation of a factorization technique to tackle the photometric stereo problem. That is to recover the surface normals and reflectance of an object from a set of images obtained under different lighting conditions. The main contribution of the proposed approach is to consider pixels in shadow and saturated regions as missing data, in order to reduce their influence to the result. Concretely, an adapted Alternation technique is used to deal with missing data. Experimental results considering both synthetic and real images show the viability of the proposed factorization‐based strategy. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 115–119, 2011. (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486235 Thu, 17 Feb 2011 21:25:02 +0100 4486235 http://www.medworm.com/index.php?rid=4486234&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20264 This article presents a new approach for studying the CP and the CSF with 18F‐fluorodeoxyglucose (FDG) positron emission tomography (PET). Ten elderly, non‐neurological patients underwent a 45‐min, dynamic FDG‐PET acquisition with scheduled 34 time frames. Our method provided successive images representing the FDG uptake dynamics, with calculation of three parameters of an exponential fitting function for the 34 frames and every voxel in the brain volume. Regions of interest in the CSF and CP were manually selected on the reconstructed map, and mean raw FDG uptake curves were reconstructed. We have monitored the kinetics of FDG uptake by the CP and the CSF during PET acquisition. The FDG kinetics in the CP differs markedly from those seen in the CSF and all other brain tissues. In ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486234 Thu, 17 Feb 2011 21:25:02 +0100 4486234 http://www.medworm.com/index.php?rid=4486233&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20252 This article introduces the frequency structure matrix as a new representation of color filter arrays (CFAs). The matrix records the frequency components of CFA filtered images and their positions in the spectrum. The matrix can be conveniently obtained by applying the symbolic DFT to the CFA pattern. With this new representation, it is easy to analyze the characteristics of CFAs and to formulate the CFA design as an optimization problem. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 101–106, 2011. (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486233 Thu, 17 Feb 2011 21:25:01 +0100 4486233 http://www.medworm.com/index.php?rid=4486232&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20243 AbstractIn this article, at first an automatic clustering technique using the concept of line symmetry property is developed. The proposed real‐coded variable string length genetic clustering technique (VGALS clustering) is able to evolve the number of clusters present in the data set automatically. Here assignment of points to different clusters is done based on the line symmetry based distance rather than the Euclidean distance. The cluster centers are encoded in the chromosomes, whose value may vary. A newly developed line symmetry based cluster validity index, LineSym‐index, is used as a measure of “goodness” of the corresponding partitioning. This validity index is able to correctly indicate the presence of clusters of different sizes as long as they are line symmetrical. A Kd... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486232 Thu, 17 Feb 2011 21:25:00 +0100 4486232 http://www.medworm.com/index.php?rid=4486231&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20271 AbstractCohomology groups and the cohomology ring of three‐dimensional (3D) objects are topological invariants that characterize holes and their relations. Cohomology ring has been traditionally computed on simplicial complexes. Nevertheless, cubical complexes deal directly with the voxels in 3D images, no additional triangulation is necessary. This could facilitate efficient algorithms for the computation of topological invariants in the image context. In this article, we present a constructive process, made up by several algorithms, to compute the cohomology ring of 3D binary‐valued digital photographs represented by cubical complexes. Starting from a cubical complex Q that represents such a 3D picture whose foreground has one connected component, we first compute the homological inf... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486231 Thu, 17 Feb 2011 21:25:00 +0100 4486231 http://www.medworm.com/index.php?rid=4486230&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20268 This article investigates the analysis of the set of straight lines whose digitization is a given digital straight segment with the help of tools from integral geometry. After a definition of a measure on such sets, we illustrate several applications of it in digital geometry for contour analysis. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 67–75, 2011. (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486230 Thu, 17 Feb 2011 21:24:59 +0100 4486230 http://www.medworm.com/index.php?rid=4486229&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20267 This article proposes a new heuristic (locally determined) algorithm for the triangulation between point sequences representing cross‐sectional contours of a surface. Such point sequence is required to be the set of vertices of a polygon representing a Jordan curve and approximating the contour. The algorithm which is applied directly to the whole point sequence, is very simple since it is based on comparisons between coordinates within a plane. The triangulation algorithm is applied to surface area estimation, where we use the polygonal approximations of cross sectional contours given by the sequences of MLP (minimal length polygon) vertices or of DSS (maximal digital straight segments) vertices. The test surfaces of known area are ellipsoids of revolution and hyperboloids of one sheet.... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486229 Thu, 17 Feb 2011 21:24:59 +0100 4486229 http://www.medworm.com/index.php?rid=4486228&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20269 This article presents a new method for fitting a digital line or plane to a given set of points in a 2D or 3D image in the presence of noise by maximizing the number of inliers, namely the consensus set. By using a digital model instead of a continuous one, we show that we can generate all possible consensus sets for model fitting. We present a deterministic algorithm that efficiently searches the optimal solution with time complexity O(Nd log N) for dimension d, where d = 2,3, together with space complexity O(N) where N is the number of points. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 45–57, 2011. (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486228 Thu, 17 Feb 2011 21:24:58 +0100 4486228 http://www.medworm.com/index.php?rid=4486227&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20272 This article presents 21 parallel thinning algorithms for (8,4) binary pictures that are derived from the sufficient conditions for topology preservation accommodated to the three parallel thinning approaches. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 37–44, 2011. (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486227 Thu, 17 Feb 2011 21:24:57 +0100 4486227 http://www.medworm.com/index.php?rid=4486226&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20270 This article introduces the tiled top–down pyramidal framework which addresses these two main constraints. Our model provides a full representation of multiresolution images with both geometrical and topological relationships. The advantage of a top–down construction scheme is twofold: the focus of attention only refines regions of interest which results in a reduction of the amount of required memory and in a refinement process that may take into account hierarchical features from previous segmentations. Moreover, the top–down model is combined with decomposition in tiles to provide an accurate memory bounding while allowing global analysis of large images. © 2011Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 28–36, 2011. (Source: International Journal of Imaging Systems... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486226 Thu, 17 Feb 2011 21:24:57 +0100 4486226 http://www.medworm.com/index.php?rid=4486225&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20265 AbstractWe propose a mathematical framework for designing filter banks that detect simple geometric features in an image, such as the planarity of the intensity function. Several theoretical results are given on how the geometry of the filters is related to the discriminative power of the filter bank. The experiment results show how the filters can be used to perform a fast segmentation of an image patch into planar segments. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 3–13, 2011. (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486225 Thu, 17 Feb 2011 21:24:56 +0100 4486225 http://www.medworm.com/index.php?rid=4486224&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20275 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4486224 Thu, 17 Feb 2011 21:24:56 +0100 4486224 http://www.medworm.com/index.php?rid=4180956&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20256 AbstractA simple probabilistic method for online video based human identification is introduced in this article. The proposed method is based on a modified version of Motion Silhouette images (MSI) and recursive probability accumulation. The modified version of MSI is named the Moving Motion Silhouette Image (MMSI). Identification probability is accumulated recursively in a Bayesian framework to draw a single conclusion from the whole gait sequence. The probability is named the accumulated posterior probability (APP) and denotes the probability based on all the information available up to now. The proposed method is tested on the well‐known publicly available NLPR and SOTON gait databases. The experimental results demonstrate the effectiveness of the proposed algorithm and indicate the f... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180956 Fri, 19 Nov 2010 12:02:24 +0100 4180956 http://www.medworm.com/index.php?rid=4180955&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20259 This article describes a low‐cost image acquisition and processing system, which measures several yarn production characteristics, namely, the fibers twist orientation, the folded yarn twist step, the folded yarn twist orientation, and the existence of single (nonfolded yarn) or multiple cables (folded yarn). The imaging hardware consists of a USB web camera coupled to an analog microscope and a monochromatic light source. The acquired images are analyzed using custom designed software based on the IMAQ Vision image program from National Instruments. A full description of the developed image processing tool is presented, together with several experimental results. The results obtained are consistent with information deduced from high‐resolution images acquired using an electron microsc... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180955 Fri, 19 Nov 2010 12:02:23 +0100 4180955 http://www.medworm.com/index.php?rid=4180954&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20253 AbstractVirtual view synthesis is one of the most important techniques to realize free viewpoint television and three‐dimensional (3D) video. In this article, we propose a view synthesis method to generate high‐quality intermediate views in such applications and new evaluation metrics named as spatial peak signal‐to‐noise ratio and temporal peak signal‐to‐noise ratio to measure spatial and temporal consistency, respectively. The proposed view synthesis method consists of five major steps: depth preprocessing, depth‐based 3D warping, depth‐based histogram matching, base plus assistant view blending, and depth‐based hole‐filling. The efficiency of the proposed view synthesis method has been verified by evaluating the quality of synthesized images with various metrics such... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180954 Fri, 19 Nov 2010 12:02:23 +0100 4180954 http://www.medworm.com/index.php?rid=4180953&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20260 AbstractTo compress multiview video and depth information, we synthesize a virtual image for the current view using color and depth data of neighboring views. In this article, we then use a view interpolation prediction scheme at the virtual image to improve the inter‐view prediction. We also propose a solution for overlapping regions and empty holes that are generated during the intermediate view synthesis process due to occlusion and disocclusion situations. Experimental results show that the proposed methods achieve approximately 0.65 dB of Peak Signal‐to‐Noise Ratio (PSNR) gain on average for multiview depth data and 0.17 dB of PSNR gain for multiview video coding, compared with the reference software, Joint Multiview Video Model 1.0. We also show that our method is even more pow... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180953 Fri, 19 Nov 2010 12:02:22 +0100 4180953 http://www.medworm.com/index.php?rid=4180952&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20257 This article refers to a new approach for detecting the image portions which are copied from another image. Besides, the present investigation discusses an algorithm effectively implemented to determine the areas formed by copy–paste operation in an image. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 367–369, 2010 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180952 Fri, 19 Nov 2010 12:02:21 +0100 4180952 http://www.medworm.com/index.php?rid=4180951&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20255 AbstractIn JPEG2000, the Cohen–Daubechies–Feauveau (CDF) 9/7‐tap wavelet filter implemented by using the conventional lifting scheme has two problems. The first problem is that the filter coefficients are remaining complex; second, the conventional lifting scheme ignores image edges in the coding process. In this article, we propose an effective wavelet lifting scheme to solve these problems. For this purpose, we design the optimal 9/7‐tap wavelet filters in two steps. In the first step, we select the appropriate filter coefficients; in the second step, we employ a median operator to consider image edges. Experimental results from using the median lifting scheme and combining filter optimization and median lifting show that our proposed methods outperform the well‐known CDF 9/7�... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180951 Fri, 19 Nov 2010 12:02:21 +0100 4180951 http://www.medworm.com/index.php?rid=4180950&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20258 This article presents a novel color edge detection algorithm based on quaternion convolution. A set of multiscale quaternion masks are presented, and the filtered results are multiplied at adjacent scales using dot product to enhance the edge structures while diluting noise. Experimental results show that the proposed method is efficient and robust for color images. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 354–358, 2010 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180950 Fri, 19 Nov 2010 12:02:20 +0100 4180950 http://www.medworm.com/index.php?rid=4180949&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20235 AbstractOne of the major challenges of the current imaging techniques is to obtain good results from images acquired with interferometric techniques. The huge complexity of these images—presence of numerous negative pixels (∼50%), undesired structures introduced by the sparse sampling of the frequencial domain, noise, etc.—advises us to use multiresolution techniques to separate the different problems or features and isolate them in different scales at each resolution level. In this article, we introduce a new tool known as curvelets to work with these images. Its good properties, oriented to classify the visual information in the image depending on its elongated structures, make it an interesting tool to separate the real information from artifacts that belong to the psf sidelobes i... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180949 Fri, 19 Nov 2010 12:02:19 +0100 4180949 http://www.medworm.com/index.php?rid=4180948&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20262 AbstractIn this article, we proposed a novel teleconferencing system that combines a facial muscle model and the techniques of face detection and facial feature extraction to synthesize a sequence of life‐like face animation. The proposed system can animate realistic 3D face images in a low‐bandwidth environment to support virtual videoconferencing. Based on the technique of feature extraction, a face detection algorithm for the virtual conferencing system is proposed in this article. In the proposed face detection algorithm, the YCbCr skin color model is used to detect the possible face area of the image; the feature points of the face is determined by using the symmetry property of the face and the gray level characteristics of the eyes and the mouth. According to the positions of th... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180948 Fri, 19 Nov 2010 12:02:18 +0100 4180948 http://www.medworm.com/index.php?rid=4180947&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20261 This article instead puts the emphasis on the learning process, testing the recognition performance of three different classifiers: support vector machine (SVM), artificial neural network and k‐nearest neighbor. Extensive experiments were run on a database of more than 5000 dermoscopy images. The obtained results show that the SVM approach outperforms the other methods reaching an average recognition rate of 82.5% comparable with those obtained by skilled clinicians. If confirmed, our data suggest that this method may improve classification results of a computer‐assisted diagnosis of melanoma. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 316–322, 2010 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180947 Fri, 19 Nov 2010 12:02:17 +0100 4180947 http://www.medworm.com/index.php?rid=4180946&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20254 AbstractImage restoration has been an important field of image processing for decades. Various methods of restoration have been studied. Meanwhile, regularization presents a very general methodology for image restoration. However, more regularization will remove more noise but will also lose more image detail, and vice versa. In this article, a novel image restoration algorithm is presented, which is derived from regularization by minimizing error energy of noise and ring artifact. Thus, this proposed algorithm is not only immune to noise but also ringing artifact, where a designed high‐pass filter is used in the algorithm proposed here such as the difference of a delta function and a blurring function or an edge operator like a Laplacian operator. This proposed algorithm can achieve hig... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180946 Fri, 19 Nov 2010 12:02:17 +0100 4180946 http://www.medworm.com/index.php?rid=4180945&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20246 AbstractStereo image is regarded as an important trend of image technology, and there is an increasing need to develop efficient measures for stereo image quality evaluation. By analyzing the main properties of human visual system that is related to stereo image, a new metric based on human visual systems (HVSs) for stereo image quality assessment is proposed in this article. This method assesses stereo images from the perspective of image quality and stereo sense. The experimental results are presented to show that the proposed metric provides results consistent with the subjective assessment and thus can be employed to reflect image quality and stereo sense. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 301–307, 2010 (Source: International Journal of Imaging Systems a... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=4180945 Fri, 19 Nov 2010 12:02:16 +0100 4180945 http://www.medworm.com/index.php?rid=3874939&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20247 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874939 Wed, 18 Aug 2010 07:40:18 +0100 3874939 http://www.medworm.com/index.php?rid=3874938&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20251 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874938 Wed, 18 Aug 2010 07:40:17 +0100 3874938 http://www.medworm.com/index.php?rid=3874937&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20250 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874937 Wed, 18 Aug 2010 07:40:17 +0100 3874937 http://www.medworm.com/index.php?rid=3874936&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20249 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874936 Wed, 18 Aug 2010 07:40:16 +0100 3874936 http://www.medworm.com/index.php?rid=3874935&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20248 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874935 Wed, 18 Aug 2010 07:40:16 +0100 3874935 http://www.medworm.com/index.php?rid=3874934&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20245 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874934 Wed, 18 Aug 2010 07:40:16 +0100 3874934 http://www.medworm.com/index.php?rid=3874933&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20244 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874933 Wed, 18 Aug 2010 07:40:15 +0100 3874933 http://www.medworm.com/index.php?rid=3874932&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20242 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874932 Wed, 18 Aug 2010 07:40:15 +0100 3874932 http://www.medworm.com/index.php?rid=3874931&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20241 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874931 Wed, 18 Aug 2010 07:40:15 +0100 3874931 http://www.medworm.com/index.php?rid=3874930&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20240 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874930 Wed, 18 Aug 2010 07:40:14 +0100 3874930 http://www.medworm.com/index.php?rid=3874929&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20239 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874929 Wed, 18 Aug 2010 07:40:14 +0100 3874929 http://www.medworm.com/index.php?rid=3874928&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20238 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3874928 Wed, 18 Aug 2010 07:40:14 +0100 3874928 http://www.medworm.com/index.php?rid=3839220&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20234 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3839220 Mon, 31 May 2010 23:00:00 +0100 3839220 http://www.medworm.com/index.php?rid=3839219&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20228 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3839219 Mon, 31 May 2010 23:00:00 +0100 3839219 http://www.medworm.com/index.php?rid=3839218&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20222 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3839218 Mon, 31 May 2010 23:00:00 +0100 3839218 http://www.medworm.com/index.php?rid=3839217&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20230 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3839217 Mon, 31 May 2010 23:00:00 +0100 3839217 http://www.medworm.com/index.php?rid=3839216&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20232 Abstract (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3839216 Mon, 31 May 2010 23:00:00 +0100 3839216 http://www.medworm.com/index.php?rid=3579938&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20231 This article compares the similarity and differences of compressed sensing dynamic MRI and video compression and discusses what MR can learn from the history of video compression research. In particular, we demonstrate that the motion estimation and compensation in video compression technique can be also a powerful tool to reduce the sampling requirement in dynamic MRI. Theoretical derivation and experimental results are presented to support our view. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 81-98, 2010 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579938 Thu, 20 May 2010 14:14:21 +0100 3579938 http://www.medworm.com/index.php?rid=3579949&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20234 This article proposes a block-based watermarking scheme that is based on the visibility of quantization noise of the color signal. The block-based scheme selects perceptually significant portions in the wavelet subband of luminance and chrominance components for robust watermark insertion and embeds the watermark with maximum distortion allowed for transparent watermarking. The strategy is to use the noise detection thresholds of color signals in the color image. By using the noise detection thresholds of wavelet coefficients in the color image, the blocks with high energy can be located and the strength of the watermark can be appropriately determined for watermark embedding. Binary watermark signals are embedded in the coefficients of perceptually significant blocks by quantization index... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579949 Mon, 17 May 2010 23:00:00 +0100 3579949 http://www.medworm.com/index.php?rid=3579948&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20233 In this article, the color space influence on different methods of morphological hierarchical segmentation is studied. For this purpose, several experimental studies are carried out on hundred images of the "Berkeley Segmentation Dataset and Benchmark" (Berkeley). On one hand, four usual and representative color spaces (RGB, YCbCr, L*a*b*, IHSL) are considered. On the other hand, three different morphological hierarchical segmentation schemes are considered. These later are the quasi flat zones, the nonparametric hierarchical watershed (waterfall algorithm) and the nested homogeneous connections. As one could expect it, the different morphological hierarchical segmentation schemes do not have the same behavior in different color spaces. We conclude by proposing a ranking of color spaces ac... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579948 Mon, 17 May 2010 23:00:00 +0100 3579948 http://www.medworm.com/index.php?rid=3579947&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20227 A new fake iris detection method based on 3D feature of iris pattern is proposed. In pervious researches, they did not consider 3D structure of iris pattern, but only used 2D features of iris image. However, in our method, by using four near infra-red (NIR) illuminators attached on the left and right sides of iris camera, we could obtain the iris image in which the 3D structure of iris pattern could be shown distinctively. Based on that, we could determine the live or fake iris by wavelet analysis of the 3D feature of iris pattern. Experimental result showed that the Equal Error Rate (EER) of determining the live or fake iris was 0.33%. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 162-166, 2010 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579947 Mon, 17 May 2010 23:00:00 +0100 3579947 http://www.medworm.com/index.php?rid=3579946&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20228 The shape context is used as the shape feature descriptor in a region-based image retrieval system. However, a given image is uneasy to be retrieved if the images are reflected. To retrieve efficiently different images, an efficient reflection invariance region-based image retrieval framework is presented in this article. In the proposed reflection invariance algorithm, the reflecting shape contexts together are first clustered and then label each cluster so that the shape contexts in each cluster have the same label. Using the histogram of label frequencies can quickly and efficiently search for similar or reflecting shapes. The experimental results have shown that our region-based image retrieval system is effective and has better retrieval performance than the existing systems. © 2010 ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579946 Mon, 17 May 2010 23:00:00 +0100 3579946 http://www.medworm.com/index.php?rid=3579945&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20222 To develop an automated lung delineation method that greatly improves the accuracy of contour extraction in SPECT lung scans with low maximum count, total counts, and/or defective contour edges, by combining deformable contour and planar image processing techniques with our existing adaptive dual exponential thresholding method. Two datasets consisting of 90 Monte Carlo simulations and 35 SPECT scans of real patients both with low maximum/total counts were used as the basis of this study. After preliminary contour extraction using dual exponential thresholding, a deformable contour algorithm was applied, combined with edge enhancement using image processing techniques such as Gaussian transformation and Sobel edge detection. Both quantitative validation via statistical measures and qualita... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579945 Mon, 17 May 2010 23:00:00 +0100 3579945 http://www.medworm.com/index.php?rid=3579944&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20215 In this article, we explore the suitability of subspace models like 2DPCA [Yang et al., IEEE Trans Pattern Anal Machine Intelligence 26 (2004), 131-137], 2DFLD [Yang et al., Pattern Recogn 38 (2005), 1125-1129], etc. for document script and language identification. They are employed to identify language and script at both paragraph and word level. Elaborate experimentation has been conducted which has revealed that they are robust enough to handle highly confusing scripts and their performance does not degrade drastically even in the presence of noise. A generic language identification has been attempted in this work, to identify languages of both Asian and European origin by considering a dataset of 20 different languages. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 14... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579944 Mon, 17 May 2010 23:00:00 +0100 3579944 http://www.medworm.com/index.php?rid=3579943&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20236 Functional magnetic resonance imaging (fMRI) and neuron electrophysiology (neurophysiology) are two well-established ways to measure brain activity. Even though the spatial and temporal resolution of these techniques is very different, both measurements show a high level of consistency, i.e., for mapping feature preferences of cortical areas. There are, however, other striking differences between fMRI and neurophysiology, for example, fMRI has good accessibility to higher cognitive functions, a bias to measure synaptic activity, and a good sensitivity to detect feedback-related activity, all of which can shed a new light on the function of well-known brain areas like primary visual cortex, V1. Classically, it is believed that V1 cells are exhaustively characterized by their complex recepti... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579943 Mon, 17 May 2010 23:00:00 +0100 3579943 http://www.medworm.com/index.php?rid=3579942&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20237 This study demonstrated that high resolution T1, T2, T2* and ADC of the rat retina could be imaged. Profile analysis of T1, T2, T2* and ADC across the retinal thickness were helpful to minimize partial volume effects. T1, T2, T2* and ADC of the rat retina were overall similar to those of the brain. Quantitative T1, T2, T2* and ADC may change in retinal diseases and their measurements could help to stage retinal disease progression and monitor therapeutic intervention. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 126-130, 2010 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579942 Mon, 17 May 2010 23:00:00 +0100 3579942 http://www.medworm.com/index.php?rid=3579941&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20230 Over the past decade, the importance of probing the anatomy of the brain has reemerged as an important field of neuroscience. In combination with functional imaging techniques, the rapid advancement of neuroimaging techniques - such as magnetic resonance imaging - and their growing applicability in studying brain morphometry has led to great advances in neuroscience research. Considering the requirements of the diverse technologies - from image processing to statistics - in performing morphometry of the brain, it is critical to have an overall understanding of this subject. The major objective of this review is to provide a practical introduction to this field. The review starts by covering basic concepts and techniques that are commonly used in morphometry of structural magnetic resonance... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579941 Mon, 17 May 2010 23:00:00 +0100 3579941 http://www.medworm.com/index.php?rid=3579940&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20229 A trendy method to understand the brain is to make a map representing the structural network of the brain, also known as the connectome, on the scale of a brain region. Indeed analysis based on graph theory provides quantitative insights into general topological principles of brain network organization. In particular, it is disclosed that typical brain networks share the topological properties, such as small-world and scale-free, with many other complex networks encountered in nature. Such topological properties are regarded as characteristics of the optimal neural connectivity to implement efficient computation and communication; brains with disease or abnormality show distinguishable deviations in the graph theoretical analysis. Considering that conventional models in graph theory are, h... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579940 Mon, 17 May 2010 23:00:00 +0100 3579940 http://www.medworm.com/index.php?rid=3579939&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20232 This article presents a method (DROID) for deformable registration of diffusion tensor (DT) images that utilizes the full tensor information by integrating the intensity and orientation features into a hierarchical matching framework. The intensity features are derived from eigen value based measures that characterize the tensor in terms of its different shape properties, such as, prolateness, oblateness, and sphericity of the tensor. Local spatial distributions of the prolate, oblate, and spherical geometry are used to create an attribute vector called the geometric/intensity feature for matching. The orientation features are the orientation histograms computed from the eigenvectors. These intensity and orientation features are incorporated into a hierarchical deformable registration fram... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3579939 Mon, 17 May 2010 23:00:00 +0100 3579939 http://www.medworm.com/index.php?rid=3289929&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20223 No abstract. (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3289929 Sat, 20 Feb 2010 15:30:50 +0100 3289929 http://www.medworm.com/index.php?rid=3289938&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20221 Magnetic resonance (MRI)-based molecular imaging methods are beginning to have impact in neuroscience. A growing number of molecular imaging agents have been synthesized and tested in vitro, but so far relatively few have been validated in the brains of live animals. Here, we discuss key challenges associated with expanding the repertoire of successful molecular neuroimaging approaches. The difficulty of delivering agents past the blood-brain barrier (BBB) is a particular obstacle to molecular imaging in the central nervous system. We review established and emerging techniques for trans-BBB delivery, including intracranial infusion, BBB disruption, and transporter-related methods. Improving the sensitivity with which MRI-based molecular agents can be detected is a second major challenge. B... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3289938 Fri, 19 Feb 2010 00:00:00 +0100 3289938 http://www.medworm.com/index.php?rid=3289937&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20218 In the past decade, MRI perfusion imaging has become increasingly important in the radiological clinic. Herein, arterial spin labeling (ASL) represents a truly noninvasive method for assessment of hemodynamic changes. Recently, whole body scanners that operate at a field strength of 7 Tesla or above have become available, carrying the promise of higher signal to noise ratio. In this article, we discuss the basic ASL methods that are available today and the problems that may be encountered when implementing ASL on a high field scanner. Particularly, B0 and B1 field inhomogeneities and fluctuations in precession frequency due to respiration were measured at the level of the brain feeding arteries. The effect of these disturbances on ASL is being discussed as are other issues such as specific... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3289937 Fri, 19 Feb 2010 00:00:00 +0100 3289937 http://www.medworm.com/index.php?rid=3289936&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20224 This review surveys the efforts that have been done so far to use magnetic resonance imaging (MRI) and other related methods to investigate the complex microstructural features of brain tissue in a quantitative and semiquantitative manner. Emphasis is put on diffusion and diffusion/relaxation methods, which were borrowed from the field of porous media nuclear magnetic resonance (NMR), and which are those that allow the most direct link between the measured NMR signal and the microscopic geometry of the investigated medium. Other methods that allow compartment-specific measurements with MR, such as multiple quantum filtered NMR of quadrupolar nuclei, are also discussed. The potential contribution of high field MRI to these methods and possible future directions are lastly discussed. © 2010... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3289936 Fri, 19 Feb 2010 00:00:00 +0100 3289936 http://www.medworm.com/index.php?rid=3289935&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20226 "Diffusion Tensor Imaging" (DTI) has the unique capability to represent the macroscopic white matter architecture. Based on DTI, tractography is able to render 3D trajectories of tracts. There are no other technique that can produce equivalent anatomical information, and, thus, tractography is a powerful method to investigate human brain anatomy. Here, we present an overview of the principles, advantages, shortcomings and possibilities of these methods. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 51-56, 2010 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3289935 Fri, 19 Feb 2010 00:00:00 +0100 3289935 http://www.medworm.com/index.php?rid=3289934&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20220 In this manuscript, we review the development of an alternative functional magnetic resonance imaging (fMRI) contrast mechanism based on the apparent diffusion coefficient (ADC), in light of the recent progress in other complementary functional imaging contrasts sensitive to cerebral blood flow (CBF) and cerebral blood volume (CBV). Specifically, we discuss the spatial and temporal characteristics of ADC fMRI in localizing neuronal activities, and also draw inference on its potential applicability to achieve fast calibrated fMRI. We found that optimized dynamic ADC contrast can lead to improved spatial localization in small vessel networks close to the true neuronal activities, while having the potential to simultaneously generate the blood oxygenation level-dependent (BOLD) and CBF/CBV co... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3289934 Fri, 19 Feb 2010 00:00:00 +0100 3289934 http://www.medworm.com/index.php?rid=3289933&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20225 Recent years have seen a strong growth of interest in multivariate approaches for analysing brain activity patterns. The primary goal of these approaches is to reveal the information represented in neuronal population codes. Here, we review how these methods have been used to relate neural activity patterns both to stimulus input and to behavioural output and how they might help to explain individual differences in behavioural performance. We examine the neuroscientific interpretation of different types of pattern-information analysis and highlight current challenges and promising future directions for this emerging field. The open challenges that we discuss are as follows: inferring the causal role of pattern information, seeking diagnostic power for functional Magnetic Resonance Imaging ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3289933 Fri, 19 Feb 2010 00:00:00 +0100 3289933 http://www.medworm.com/index.php?rid=3289932&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20216 Balanced-steady-state free precession (b-SSFP) functional magnetic resonance imaging (fMRI) encompasses several recently developed methods that utilize b-SSFP acquisition for fMRI. Short repetition time (TR) and readout durations of b-SSFP allow distortion-free acquisition, 3D imaging, and high-resolution isotropic voxel acquisition. b-SSFP fMRI can be categorized into two different classes depending on which contrast mechanism it exploits. Transition-band b-SSFP fMRI is a technique that utilizes the sharp transition of the b-SSFP profile relying on the fact that oxygenated and deoxegenated hemoglobin has different resonance frequencies. On the other hand, passband b-SSFP fMRI utilizes b-SSFP in the relatively large flat portion of the b-SSFP off-resonance spectrum where oxygenation contra... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3289932 Fri, 19 Feb 2010 00:00:00 +0100 3289932 http://www.medworm.com/index.php?rid=3289931&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20217 Functional magnetic resonance imaging (fMRI) provides the ability to image blood dynamics through the entire brain with a high spatial resolution. However, the temporal resolution is much slower than the underlying neuronal activity one seeks to infer. Recent developments in rapid imaging allow 3D fMRI studies to be performed at a temporal resolution of 100 ms; a 10-fold increase compared to standard approaches. This increase in temporal resolution offers a number of potential benefits. First, it allows the focus of analysis to be shifted from changes in blood flow taking place 5-8 s after neuronal activity to more transient changes taking place immediately following activation. We argue that studying these changes provides valuable information about the relative timing of activation acros... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3289931 Tue, 16 Feb 2010 00:00:00 +0100 3289931 http://www.medworm.com/index.php?rid=3289930&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20219 The major radiofrequency engineering challenges of high-field MR neuroimaging are as follows: (1) to produce a strong, homogeneous transmit B1 field, while remaining within regulatory guidelines for tissue power deposition and (2) to receive the signal with the maximum signal-to-noise and the greatest flexibility in terms of utilizing the benefits of parallel imaging. Borrowing from developments in electromagnetic hyperthermia, the first challenge has been met by the use of transmit arrays, in which the input power to each element of the array can be varied in terms of magnitude and phase. Optimization of these parameters, as well as the form of the applied RF pulse, leads to very homogeneous B1 fields throughout the brain. The design of large receive arrays, using impedance-mismatched pre... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=3289930 Tue, 16 Feb 2010 00:00:00 +0100 3289930 http://www.medworm.com/index.php?rid=2969341&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20203 With the critical innovations of using submillimeter transducers and multiband analysis of the first arrival pulse, a high-resolution ultrasonic transmission tomography (HUTT) system has been built and tested to produce multiband images of biological organs at submillimeter resolution. Since the resulting multiband images consist of frequency-dependent attenuation coefficients (relative to water reference) of transmitted ultrasound pulses, their contrast and sharpness depend on the specific frequency band(s) used for image formation. Even though this multiband representation provides a powerful tool for soft-tissue differentiation, it hinders visual inspection and limits the visual interpretation of image contents in a short time. To facilitate the visual interpretation of HUTT multiband i... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969341 Sat, 07 Nov 2009 15:03:47 +0100 2969341 http://www.medworm.com/index.php?rid=2969352&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20214 This article proposes an image compression method based on multiple models for the probabilities of patterns (MMPP method) to encode a gray-level image f. First, the MMPP method employs a median edge detector (MED) to reduce the entropy of f. The intensities of two adjacent pixels in an image are usually close to each other. A base switching transformation (BST) is then used to lessen the spatial redundancy of f. Finally, the arithmetic encoding method is applied to further encode the data generated after the processing of MED and BST. To reduce the memory space required to hold f, the MMPP method classifies the data and then compresses the data in each cluster by the arithmetic encoding method based on different probability tables. The experimental results show that mostly the MMPP method... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969352 Fri, 06 Nov 2009 00:00:00 +0100 2969352 http://www.medworm.com/index.php?rid=2969351&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20213 A high-efficiency and contrast-enhanced halftoning approach is presented in this article. The contrast of digital image depends highly on the nature of the ambient lighting and the quality of the lens. The required processing time skyrockets when a high printed work of high resolution and quality is needed. In this article, we use the benefits of high-speed ordered dithering and high-quality error diffusion to simultaneously solve the problems described earlier. Experimental results demonstrate that this technique is able to enlarge the dynamic range of the histogram and achieve improvement in execution efficiency of 15-47% with the tested images. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 356-361, 2009 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969351 Fri, 06 Nov 2009 00:00:00 +0100 2969351 http://www.medworm.com/index.php?rid=2969350&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20212 This article presents palm-print recognition based on cross-band fusion by energy weight and comprehensively takes into account the noisy properties of various sub-bands in single wavelet level and decomposition coefficient of the adjacent sub-band, thus the method of energy weight based on palm-print image is employed. Then two-dimensional principal component analysis (2DPCA) is employed for dimension reduction and decorrelated. Finally, a nearest neighbor classifier is used for palm-print recognition. Experimental results on Hong Kong PolyU palm-print database show that correct recognition rate can reach 100% by the method presented within this article. Correct recognition rate and recognition efficiency is higher than that of 2DPCA and WT + DCT + 2DPCA (Wavelet Transform, Discrete Cosin... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969350 Fri, 06 Nov 2009 00:00:00 +0100 2969350 http://www.medworm.com/index.php?rid=2969349&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20211 An intra mode selection scheme is proposed in this work, which supports both downsizing transcoding and re-quantization transcoding simultaneously. In the proposal, a total number of nonzero coefficients in precoded frame is used as criterion and a thresholding method is applied to select intra macroblock mode in re-encoder. To calculate this threshold, which is related to re-quantization parameter (denoted as Qr), we propose a Th_I-Qr model which includes direct method and percentage I16MB method. In the former, an exponent model is proposed to describe relationship between the threshold and the Qr; while in the latter, the threshold Th_I is converted into percentage of macroblocks with I16MB mode in the downsized frame (denoted as per_16), and relationship between the per_16 and the Qr i... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969349 Fri, 06 Nov 2009 00:00:00 +0100 2969349 http://www.medworm.com/index.php?rid=2969348&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20210 Color-edge detection is an important research task in the field of image processing. Efficient and accurate edge detection will lead to higher performance of subsequent image processing techniques, including image segmentation, object-based image coding, and image retrieval. To improve the performance of color-edge detection while considering that human eyes are ultimate receiver of color images, the perceptually insignificant edges should avoid being over-detected. In this article, a color-edge detection scheme based on the perceptual color contrast is proposed. The perceptual color contrast is defined as the visible color difference across an edge in the CIE-Lab color space. A perceptual metric for measuring the visible color difference of a target color pixel is defined by utilizing the... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969348 Fri, 06 Nov 2009 00:00:00 +0100 2969348 http://www.medworm.com/index.php?rid=2969347&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20209 This article presents three contributions over previous research. (1) A new focus assessment method is proposed to measure accurate focus scores regardless of motion blurring. (2) Previous research restored coexisting motion-and-optical blurred images in terms of visibility, but in this article, we restored them in terms of recognition. (3) We used a modified CLS (Constrained Least Square) filter to prevent the zero-crossing of the PSF (Point Spread Function) of motion blurring with a uniform shape. So, the iris recognition accuracy was better than when using a conventional CLS filter. Experimental results showed that the EER was 0.796% when using the proposed method and it was 1.431% when not using the proposed method. Consequently, the EER was reduced as much as 0.635% (1.431-0.796%) whe... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969347 Fri, 06 Nov 2009 00:00:00 +0100 2969347 http://www.medworm.com/index.php?rid=2969346&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20208 Machine vision based analysis provides a novel technology for froth flotation monitoring. Froth images collected are characterized by fully occupied bubbles with different size and shape under various illuminations. Convex bubbles lead to the formation of white spots that seriously affect froth color measurement. In this article, specular highlights are detected and preprocessed so as to estimate underlying color of white spots region. Because of the fact that color information is believed to be related to flotation performance, therefore, after the application of highlight inpainting, multivariate image analysis is proposed to extract color features, which are further related to mineral grades by a orthogonal least square regression model. The established relationship provides a promising... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969346 Fri, 06 Nov 2009 00:00:00 +0100 2969346 http://www.medworm.com/index.php?rid=2969345&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20207 This article proposes an adaptive steganographic algorithm that embeds secret data in a compressed video stream using temporal and spatial features of the video signal and human visual system characteristics. Qualified-DCT coefficients of I-VOP and motion vectors of P-VOP and B-VOP are used for spatial and temporal features of the video, respectively. Embedded-data are extracted without using the original video and there is no need for full decompression. Experimental results demonstrate that the proposed algorithm has high imperceptibility and capacity. Furthermore, the bit rate remains approximately constant. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 306-315, 2009 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969345 Fri, 06 Nov 2009 00:00:00 +0100 2969345 http://www.medworm.com/index.php?rid=2969344&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20206 This article presents a computational approach to the imaging of a partially immersed imperfectly conducting cylinder. An imperfectly conducting cylinder of unknown shape and conductivity scatters the incident transverse magnetic (TM) wave in free space while the scattered field is recorded outside. Based on the boundary condition and the measured scattered field, a set of nonlinear integral equations, and the inverse scattering problem are reformulated into an optimization problem. We use genetic algorithm (GA) to reconstruct the shape and the conductivity of a partially immersed imperfectly conducting cylinder. The genetic algorithm is then used to find out the global extreme solution of the cost function. Numerical results demonstrated that, even when the initial guess is far away from ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969344 Fri, 06 Nov 2009 00:00:00 +0100 2969344 http://www.medworm.com/index.php?rid=2969343&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20205 A computer-aided diagnosis (CAD) system has been developed for the detection of bronchiectasis from computed tomography (CT) images of chest. A set of CT images of the chest with known diagnosis were collected and these images were first denoised using Wiener filter. The lung tissue was then segmented using optimal thresholding. The Pathology Bearing Regions (PBRs) were then extracted by applying pixel-based segmentation. For each PBR, a gray level co-occurrence matrix (GLCM) was constructed. From the GLCM texture features were extracted and feature vectors were constructed. A probabilistic neural network (PNN) was constructed and trained using this set of feature vectors. The images together with the PBRs and the corresponding feature vector and diagnosis were stored in an image database.... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969343 Fri, 06 Nov 2009 00:00:00 +0100 2969343 http://www.medworm.com/index.php?rid=2969342&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20204 We have developed a discrete-time dynamic image segmentation system consisting of chaotic neurons and a global inhibitor. Our system receives an image with isolated regions and can output segmented images in time series based on oscillatory responses of chaotic neurons. In this article, we derive a reduced model to find intrinsic properties of the system of dynamic image segmentation. Using numerical method for analyzing dynamical systems, we investigated bifurcation phenomena of a fixed point observed in the reduced model. As the results, in a model of two coupled chaotic neurons, we found that a set of Neimark-Sacker bifurcations causes the generation of an in-phase oscillatory response, which is unsuitable for the purpose of dynamic image segmentation. The bifurcation analysis gives app... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2969342 Fri, 06 Nov 2009 00:00:00 +0100 2969342 http://www.medworm.com/index.php?rid=2736482&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20176 Active camouflage is a technique for occluding objects disappear from the observer. Current implementations make assumptions on the viewpoints of both the observer and the camouflaged target. In this work, we present a framework of view-dependent planar scene camouflage. The cameras representing the observer and the occluding object are placed in general positions. The images captured by the object camera are transformed to the observer viewpoint to generate globally consistent visual data for transparent camouflage. Experimental results are presented for real scene images. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 167-174, 2009 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736482 Thu, 27 Aug 2009 12:47:51 +0100 2736482 http://www.medworm.com/index.php?rid=2736493&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20200 Quantitative single-photon emission computed tomography can be well achieved if photon attenuation is taken into account in the reconstruction process. Using a transmission scan is a common approach. A dramatic simplification could be made if the attenuation map could be obtained from the emission data. In this article, we propose a new method to estimate the attenuation map using the data consistency conditions of the attenuated Radon transform. It is based on deriving boundaries of the constant regions of the true attenuation map using an iterative algorithm. This new method is tested by Monte Carlo simulations with the attenuation and scattering effects. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 271-276, 2009 (Source: International Journal of Imaging Systems and Te... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736493 Tue, 04 Aug 2009 23:00:00 +0100 2736493 http://www.medworm.com/index.php?rid=2736492&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20198 This article aims to develop a method for the detection and segmentation of a cytoplast and nucleus from a cervix smear image. First, the technique of equalization method with Gaussian filter is adopted to eliminate noise in the image. Second, a new edge enhancement technique is proposed to work out the coarseness of each pixel, which is later used as a determining characteristic of reinforced object images. A two-group object enhancement technique is then used to reinforce this object according to rough pixels. Third, the proposed detector enhances the gradients of the edges of the cytoplast and nucleus while suppressing the noise gradients, and then specifies the pixels with higher gradients as possible edge pixels. Finally, it picks out the two longest closed curves constructed by part ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736492 Tue, 04 Aug 2009 23:00:00 +0100 2736492 http://www.medworm.com/index.php?rid=2736491&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20202 The objective of this article is to investigate contemporary technologies for creating accurate 3D digital models of artifacts from the Maori and Pacific heritage and to establish a generic digitization methodology so that the 3D models can be archived and exhibited both over the internet and within museum displays. This process involves procedures for selecting artifacts that are suitable for laser scanning and then setting up the artifact for scanning. This is followed by the actual scanning and postprocessing stages. To achieve this, the Polhemus FastSCAN laser scanner has been used to collect raw point cloud surface data from artifacts of various sizes, shapes, textures, colors, and materials. The article explains the generic steps developed for postprocessing of raw scan data in the f... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736491 Tue, 04 Aug 2009 23:00:00 +0100 2736491 http://www.medworm.com/index.php?rid=2736490&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20201 This article presents a novel method of plant classification using Gabor wavelet filters to extract texture filters in a foliar surface. The aim of this promising method is to add to the results obtained by other leaf attributes (such as shape, contour, color, among others), increasing, therefore, the percentage of classification of plant species. To corroborate the efficiency of the technique, an experiment using 20 species from Brazilian flora was done and discussed. The results are also compared with texture Fourier descriptors and cooccurrence matrices. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 236-243, 2009 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736490 Tue, 04 Aug 2009 23:00:00 +0100 2736490 http://www.medworm.com/index.php?rid=2736489&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20199 In TV program distribution, the receiver's identification information is embedded into video data in order to trace illegal distributors, and video data are encrypted in order to protect the confidentiality against unauthorized users. In traditional method, the TV program is firstly fingerprinted, then encrypted, and finally transmitted. For N receivers, N times of encryption, and N times of fingerprinting operations are required, which makes the sender of high loading. In another method, the media content is decrypted and fingerprinted simultaneously by the joint fingerprint embedding and decryption, which is difficult to obtain reasonable performances. In this article, a commutative encryption and fingerprinting scheme is proposed to reduce the sender's loading. In this scheme, the TV pr... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736489 Tue, 04 Aug 2009 23:00:00 +0100 2736489 http://www.medworm.com/index.php?rid=2736488&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20197 This article presents a new idea of using a noniterative method to compensate for the spatially variant PSF. This method first further blurs the image with a nonstationary kernel so that the resultant image has a stationary PSF, then deblurs the resultant image using an efficient decovolution technique. The proposed method is illustrated and implemented by single photon emission computed tomography applications. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 221-226, 2009 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736488 Tue, 04 Aug 2009 23:00:00 +0100 2736488 http://www.medworm.com/index.php?rid=2736487&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20196 In this article, an efficient and novel approach for video data association is developed. This new method is formulated as a search across the hypotheses space defined by the possible association among tracks and detections, carried out for each frame of a video sequence. The full data association problem in visual tracking is formulated as a combinatorial hypotheses search with a heuristic evaluation function taking into account structural and specific information such as distance, shape, color, etc. To guarantee real-time performance, a time limit is set for the search process explore alternative solutions. This time limit defines the upper bound of the number of evaluations depending on search algorithm efficiency. Estimation distribution algorithms are proposed as an efficient evolutio... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736487 Tue, 04 Aug 2009 23:00:00 +0100 2736487 http://www.medworm.com/index.php?rid=2736486&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20195 Image segmentation is an important task in image processing and analysis. Many segmentation methods have been used to segment satellite images. The success of each method depends on the characteristics of the acquired image such as resolution limitations and on the percentage of imperfections in the process of image acquisition due to noise. Many of these methods require a priori knowledge which is difficult to obtain. Some of them are parametric statistical methods that use many parameters which are dependent on image property. In this article, a new unsupervised nonparametric method is developed to segment satellite images into homogeneous regions without any a priori knowledge. The new method is called hybrid variable genetic algorithm (HVGA). The variability is found in the variable nu... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736486 Tue, 04 Aug 2009 23:00:00 +0100 2736486 http://www.medworm.com/index.php?rid=2736485&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20194 This article presents a new tracking method based on parametric active contour models. In the proposed method, a new pressure energy called "texture pressure energy" is added to the energy function of the parametric active contour model to detect and track a texture target object in a texture background. In this scheme, the texture features of the contour are calculated by a moment-based method. Then, by comparing these features with texture features of the target object, the contour curve is expanded or contracted to be adapted to the object boundaries. Experimental results show that the proposed method is more efficient and accurate in the tracking of objects compare to the traditional ones, when both object and background are textures in nature. © 2009 Wiley Periodicals, Inc. Int J Ima... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736485 Tue, 04 Aug 2009 23:00:00 +0100 2736485 http://www.medworm.com/index.php?rid=2736484&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20193 This article proposes a new finger vein recognition method using minutia-based alignment and local binary pattern (LBP)-based feature extraction. Our study makes three novelties compared to previous works. First, we use minutia points such as bifurcation and ending points of the finger vein region for image alignment. Second, instead of using the whole finger vein region, we use several extracted minutia points and a simple affine transform for alignment, which can be performed at fast computational speed. Third, after aligning the finger vein image based on minutia points, we extract a unique finger vein code using a LBP, which reduces false rejection error and thus the equal error rate (EER) significantly. Our resulting EER was 0.081% with a total processing time of 118.6 ms. © 2009 Wil... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736484 Tue, 04 Aug 2009 23:00:00 +0100 2736484 http://www.medworm.com/index.php?rid=2736483&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20190 In this article, a novel denoising technique based on custom thresholding operating in the wavelet transform domain is proposed. The denoising process is spatially adaptive and also sub-band adaptive. To render the denoising algorithm space adaptive, a Vector Quantization (VQ)-based algorithm is used. The design of the VQ is based on Expectation Maximization (EM) algorithm. The results of the algorithm is demonstrated on SAR images corrupted by speckle noise. Experimental results show that Custom thresholding function outperforms the traditional soft, hard, and Bayes threshoding functions, improving the denoised results significantly in terms of Peak Signal to Noise Ratio (PSNR). © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 175-178, 2009 (Source: International Journal of... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2736483 Tue, 04 Aug 2009 23:00:00 +0100 2736483 http://www.medworm.com/index.php?rid=2410424&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20192 No abstract. (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410424 Fri, 15 May 2009 19:50:06 +0100 2410424 http://www.medworm.com/index.php?rid=2410436&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20179 An algorithm of linear time complexity is presented to label connected components of a binary image by a quadtree. For a given node, the search for all adjacent nodes is carried out in O(1) (i.e., constant time complexity for the worst case) using our formerly presented algorithm in (Aizawa et al., 3rd International Symposium on Communications, Control, and Signal Processing,, 505-510), whereas it explores all possible adjacencies for each node in a usual way. Then during the process of tree formulation in the search, all equivalent relations of labels are stored as lists. Time complexity of the algorithm is O(B+W) for the worst case and its auxiliary space is no more than O(B), where B and W correspond to the number of leaf nodes in a quadtree representing black and white quadrants, respe... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410436 Wed, 13 May 2009 04:00:00 +0100 2410436 http://www.medworm.com/index.php?rid=2410435&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20182 In the digital image processing, digital distances are useful; distances based on neighborhood sequences are widely used. In this article, the diamond grid is considered, that is, the three-dimensional grid of carbon atoms in the diamond crystal. An algorithm to compute a shortest path defined by a neighborhood sequence between any two points in the diamond grid is presented. A formula to compute the distance based on neighborhood sequences with two neighborhood relations is given. The metric and nonmetric properties of some distances based on neighborhood sequences are also discussed. Finally, the constrained distance transformation is shown. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 146-157, 2009. (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410435 Wed, 13 May 2009 04:00:00 +0100 2410435 http://www.medworm.com/index.php?rid=2410434&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20185 In the context of a syntactic approach to pattern recognition, there have been several studies in the last few decades ontheoretical models for generating or recognizing two-dimensional objects, pictures, and picture languages. Motivated by these studies, we have introduced a new notion of recognizability for a class of picture languages called iso-picture languages through iso-triangular tiling systems (ITS) and studied the properties of these languages [Kalyani et al.,]. In [Kalyani et al.,], we introduced iso-triangular domino systems (IDS) to recognize iso-picture languages, and proved the equivalence of ITS and IDS. In [Kalyani et al.,], we have constructed a two-dimensional online tessellation automaton (IPOTA) to recognize an iso-picture language and presented an algorithm to learn ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410434 Wed, 13 May 2009 04:00:00 +0100 2410434 http://www.medworm.com/index.php?rid=2410433&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20186 In algebraic topology, compact two-dimensional manifolds are usually dealt through a well-defined class of words denoting polygonal presentations. In this article, we show how to eliminate the useless bureaucracy intrinsic to word-based presentations by considering very simple combinatorial structures called pq-permutations. Thanks to their specific effectiveness, pq-permutations induce a rewriting system P able to compute, in a very easy and intuitive way, the quotient surface associated with any given polygonal presentation. The system P is shown to enjoy both the fundamental computational properties of strong normalization and strict strong confluence. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 132-139, 2009. (Source: International Journal of Imaging Systems and Tec... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410433 Wed, 13 May 2009 04:00:00 +0100 2410433 http://www.medworm.com/index.php?rid=2410432&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20188 We present a supervised classification method which represents each class by one or more optimum-path trees rooted at some key samples, called prototypes. The training samples are nodes of a complete graph, whose arcs are weighted by the distances between the feature vectors of their nodes. Prototypes are identified in all classes and the minimization of a connectivity function by dynamic programming assigns to each training sample a minimum-cost path from its most strongly connected prototype. This competition among prototypes partitions the graph into an optimum-path forest rooted at them. The class of the samples in an optimum-path tree is assumed to be the same of its root. A test sample is classified similarly, by identifying which tree would contain it, if the sample were part of the... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410432 Wed, 13 May 2009 04:00:00 +0100 2410432 http://www.medworm.com/index.php?rid=2410431&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20187 This article presents, based on the assumption that PV effect could be fully described by a tissue mixture model, a theoretical solution to the MAP-EM segmentation algorithm, as opposed to our previous approximation which simplified the posteriori cost function as a quadratic term. It was found out that the theoretically-derived solution existed in a set of high-order nonlinear equations. Despite of the induced computational complexity when seeking for optimum numerical solutions to nonlinear equations, potential gains in robustness, consistency and quantitative precision were noticed. Results from both synthetic digital phantoms and real patient bladder MR images were presented, demonstrating the accuracy and efficiency of the presented theoretical MAP-EM solution. © 2009 Wiley Periodica... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410431 Wed, 13 May 2009 04:00:00 +0100 2410431 http://www.medworm.com/index.php?rid=2410430&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20180 This article describes the AnimVideo rendering tool that was developed for stylizing videos with temporal coherence. The temporal coherence is achieved by first fully segmenting the input video with a fast fuzzy segmentation algorithm that uses hybrid color spaces and motion information. The result of the segmentation algorithm is used to constrain the result of an optical flow algorithm, given as dense optical flow maps that are then used to correctly move, remove, or add structural drawing elements. The combination of these two methods is referred to as constrained optical flow, and we also provide the option of initializing the optical flow computation with displacement maps computed by homographies that map objects in adjacent frames. Also, we briefly describe some stylized rendering m... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410430 Wed, 13 May 2009 04:00:00 +0100 2410430 http://www.medworm.com/index.php?rid=2410429&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20183 Separating or segmenting complex activities into basic action primitives is important for event recognition and other applications. In this article, simple approaches are presented for appearance-based action recognition, as well as motion segmentation into its action primitives. Optical flow is computed and split into four channels based on four directions, namely, up, down, left, and right. Based on these four motion vectors, motion history and the corresponding energy templates are generated. These are used for action recognition. Moreover, to segment sequential activity, the temporal motion segmentation (TMS) method is proposed based on the concept of history templates. Based on the total pixel volumes on these templates and their related variations, various directions of the action pr... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410429 Wed, 13 May 2009 04:00:00 +0100 2410429 http://www.medworm.com/index.php?rid=2410428&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20184 Video surveillance of large facilities, such as airports, rail stations, and casinos, is developing rapidly. Cameras installed at such locations often overlook large crowds, which makes problems such as activity and scene understanding very challenging. Traditional activity understanding techniques, which rely on input from lower level processing units dealing with background subtraction, human detection, and tracking, are unable to cope with frequent occlusions in such scenes. We propose a novel spatiotemporal segmentation and activity recognition framework that bypasses these commonly used low-level modules. We model each local spatiotemporal patch as a dynamic texture. Using a suitable distance metric to compare two local patches based on their estimated dynamic texture parameters, we s... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410428 Wed, 13 May 2009 04:00:00 +0100 2410428 http://www.medworm.com/index.php?rid=2410427&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20181 We use a MRF with asymmetric pairwise compatibility constraints between direct pixel neighbors to solve a constrained binary image segmentation task. The model is constraining shape and alignment of individual contiguous binary segments by introducing auxiliary labels and their pairwise interactions. Such representation is not necessarily unique. We study several ad-hoc labeling models for binary images consisting of nonoverlapping rectangular contiguous regions. Nesting and equivalence of these models are studied. We observed a noticeable increase in performance even in cases when the differences between the models were seemingly insignificant. We use the proposed models for segmentation of windowpanes and windows in orthographically rectified façade images. Segmented window patches are ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410427 Wed, 13 May 2009 04:00:00 +0100 2410427 http://www.medworm.com/index.php?rid=2410426&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20191 We propose an approach for data clustering based on optimum-path forest. The samples are taken as nodes of a graph, whose arcs are defined by an adjacency relation. The nodes are weighted by their probability density values (pdf) and a connectivity function is maximized, such that each maximum of the pdf becomes root of an optimum-path tree (cluster), composed by samples "more strongly connected" to that maximum than to any other root. We discuss the advantages over other pdf-based approaches and present extensions to large datasets with results for interactive image segmentation and for fast, accurate, and automatic brain tissue classification in magnetic resonance (MR) images. We also include experimental comparisons with other clustering approaches. © 2009 Wiley Periodicals, Inc. Int J... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410426 Wed, 13 May 2009 04:00:00 +0100 2410426 http://www.medworm.com/index.php?rid=2410425&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20189 We propose and discuss a novel method for enhancing books and other printed materials with layers of digital data blended with their page content. In document digitizing a patented Cluster Pattern Interface (CLUSPI®) is used for providing orientation and position feedback that establishes connections with an electronic multimedia dictionary employing pictures, multilingual word explanations, and pronunciation samples. The work is mainly oriented to young children and aims to enhance their reading comprehension and to develop their language learning skills. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 39-49, 2009. (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2410425 Wed, 13 May 2009 04:00:00 +0100 2410425 http://www.medworm.com/index.php?rid=2171764&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20173 The objective of this article is to present the trade-off analysis of resolving capability of diffraction tomography between aperture size and illumination signal bandwidth based on the span of spatial spectral coverage. The analysis is conducted on both the transmission and reflection modes, and can be generalized into various data acquisition configurations. In addition, the analysis provides an important link to other tomographic imaging modalities such as the classical X-ray tomography and synthetic aperture radar systems. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 1-4, 2009 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2171764 Tue, 10 Feb 2009 11:12:40 +0100 2171764 http://www.medworm.com/index.php?rid=2171768&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20175 In previous work, we designed space fiducials with the aim of making camera pose determination as noise-insensitive as possible. These fiducials turned out to be sets of points that formed concentric regular polyhedra. Here, we apply an idea of Dementhon and Davis and test and analyze an iterative linear algorithm in conjunction with our optimal fiducials to increase the accuracy of the computed camera pose. We also analyze under what circumstances this iterative algorithm is guaranteed to converge to the correct solution. Comprehensive computer simulations illustrate the behavior of the algorithm and the degree of improvement in pose determination in case of convergence. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 27-36, 2009 (Source: International Journal of Imaging S... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2171768 Mon, 09 Feb 2009 05:00:00 +0100 2171768 http://www.medworm.com/index.php?rid=2171767&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20174 A new technique for color reduction of complex document images is presented in this article. It reduces significantly the number of colors of the document image (less than 15 colors in most of the cases) so as to have solid characters and uniform local backgrounds. Therefore, this technique can be used as a preprocessing step by text information extraction applications. Specifically, using the edge map of the document image, a representative set of samples is chosen that constructs a 3D color histogram. Based on these samples in the 3D color space, a relatively large number of colors (usually no more than 100 colors) are obtained by using a simple clustering procedure. The final colors are obtained by applying a mean-shift based procedure. Also, an edge preserving smoothing filter is used ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2171767 Mon, 09 Feb 2009 05:00:00 +0100 2171767 http://www.medworm.com/index.php?rid=2171766&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20177 The analysis of holograms obtained using a Conoscopic setup is a very complex subject, given their nature. Holograms contain the 3D depth information about an object whose surface is to be measured and later reconstructed. The recovery of depth information has so far been carried out using mathematical transforms in combination with linear regression techniques. Here the Hough transform, a useful Computer Vision technique for detecting features in images is adapted to the analysis of holograms in order to establish distance relationships for a given object. The captured images of holograms are pre-processed and subsequently analyzed for characteristic patterns that are later used in finding the distance to an object. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 10-13, 20... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2171766 Mon, 09 Feb 2009 05:00:00 +0100 2171766 http://www.medworm.com/index.php?rid=2171765&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20172 We describe, after that, our proposed reversible watermarking method used for integrity verification, we also evaluate image visual quality after watermark embedding and the effectiveness of locating tampered regions. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 5-9, 2009 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2171765 Mon, 09 Feb 2009 05:00:00 +0100 2171765 http://www.medworm.com/index.php?rid=2015759&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20169 Thresholding is frequently used for image segmentation. One of the most popular approach to thresholding is the moment-preserving thresholding method proposed by Tsai in 1985. However, it does not work well when the peaks of a histogram have a great size variation. Hence, in this study we propose a simple and effective improvement in Tsai's method such that suitable thresholds can be found even when the histogram has peaks with a great size variation. Experimental results show the effectiveness of the proposed improvement. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 365-370, 2008 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2015759 Fri, 05 Dec 2008 05:00:00 +0100 2015759 http://www.medworm.com/index.php?rid=2015758&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20171 We present motivation for performing the filtering step of the widely used filtered back-projection algorithm in a non-Radon domain. For square-error optimal penalized-likelihood regularization, filtering in a domain for which the true projection data is sparse in the angle dimension yields coefficients that are more faithful to the ideal filtered data than directly filtering the observed Radon-domain data. In contrast to traditional regularization techniques that filter each projection independently, the proposed filtering technique delivers improved reconstructions by exploiting the correlation of the data in the angle dimension. This enables meaningful reconstructions to be created even from very noisy projection data. In addition, this approach allows for simple penalty matrices to be ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2015758 Fri, 05 Dec 2008 05:00:00 +0100 2015758 http://www.medworm.com/index.php?rid=2015757&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20166 Brain function is widely investigated with functional magnetic resonance imaging (fMRI) in humans and animals. In fMRI, the time courses of voxels typically reflect the local blood-oxygen level, which is taken as an indicator of neuronal activity. Voxel time-course correlations are often explicitly modeled and interpreted in terms of neuronal interactions. They also affect standard analyses that do not explicitly target neuronal interactions. As a consequence, time-course correlations between voxels influence conclusions about cognitive and physiological brain processes in many studies. However, voxel correlations are known to arise not only from cognitive and physiological processes, but also as artifacts of fMRI techniques such as the commonly used echoplanar imaging. We empirically demo... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2015757 Fri, 05 Dec 2008 05:00:00 +0100 2015757 http://www.medworm.com/index.php?rid=2015756&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20170 The usefulness of fuzzy segmentation algorithms based on fuzzy connectedness principles has been established in numerous publications. New technologies are capable of producing larger-and-larger datasets and this causes the sequential implementations of fuzzy segmentation algorithms to be time-consuming. We have adapted a sequential fuzzy segmentation algorithm to multiprocessor machines. We demonstrate the efficacy of such a distributed fuzzy segmentation algorithm by testing it with large datasets (of the order of 50 million points/voxels/items): a speed-up factor of [sim]5 over the sequential implementation seems to be the norm. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 336-344, 2008 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2015756 Fri, 05 Dec 2008 05:00:00 +0100 2015756 http://www.medworm.com/index.php?rid=2015755&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20168 Certain features such as small vascular lesions seen in human MRI (Magnetic Resonance Imaging) are detected reliably only in postmortem histological samples by microscopic imaging. Co-registration of these microscopically detected features to their corresponding locations in the in vivo images would be of great benefit to understanding the MRI signatures of specific diseases. Using nonlinear Polynomial transformation, we report a method to co-register in vivo MRIs to microscopic images of histological samples drawn off the postmortem brain. The approach utilizes digital photographs of postmortem slices as an intermediate reference to co-register the MRIs to microscopy. The overall procedure is challenging due to gross structural deformations in the postmortem brain during extraction and su... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2015755 Fri, 05 Dec 2008 05:00:00 +0100 2015755 http://www.medworm.com/index.php?rid=2015754&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20167 Because of the complex nature of the human brain, a full understanding of its various group specific variation factors such as volume, shape, and location related to age, gender, ethnic, and disease might be provided in both structural and functional neuroimaging studies. To serve this purpose, a novel approach for characterizing the group variability information using group specific labeled probabilistic maps was introduced in this article. An automatic labeling technique was applied to encode group specific probabilistic information for each region of interests (ROIs) covering the overall cortical region and a probabilistic pattern analytic method was proposed to assess the difference in the spatial extent between 70 schizophrenics and 70 controls in the common space. From our proposed m... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2015754 Fri, 05 Dec 2008 05:00:00 +0100 2015754 http://www.medworm.com/index.php?rid=2015753&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20157 The objective of this work is to provide the formulation of the spatial-frequency weighting of distributed filtered backward propagation in multiple-projection diffraction tomography. This formulation provides the precise frequency-weighting characteristics for the generalized tomographic data-acquisition configurations. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 307-309, 2008 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2015753 Fri, 05 Dec 2008 05:00:00 +0100 2015753 http://www.medworm.com/index.php?rid=2015752&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20160 The main problem of photographing stained glass windows is setting the correct exposure. An overall average exposure setting frequently results in the highlight areas being overexposed, or dark area being under-exposed, or both. It is therefore necessary to provide a suitable set of image processing tools to correct the image defects. In this work describe several algorithms to solve this problem of nonuniformity of illumination. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 296-306, 2008 (Source: International Journal of Imaging Systems and Technology) International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=2015752 Fri, 05 Dec 2008 05:00:00 +0100 2015752 http://www.medworm.com/index.php?rid=1882855&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20158 This paper presents an inverse scattering problem for recovering the shapes of multiple conducting cylinders with the immersed targets in a half-space by genetic algorithm. Two separate perfectly conducting cylinders of unknown shapes are buried in one half-space and illuminated by transverse magnetic (TM) plane wave from the other half-space. Based on the boundary condition and the measured scattered field, a set of nonlinear integral equations are derived, and the electromagnetic imaging problem is reformulated into an optimization problem. The improved steady state genetic algorithm is used to find out the global extreme solution. Numerical results are given to demonstrate the performance of the inverse algorithm. Good reconstruction can be obtained even when the initial guesses are far... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=1882855 Thu, 16 Oct 2008 04:00:00 +0100 1882855 http://www.medworm.com/index.php?rid=1882854&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20159 True motion estimation is necessary for deinterlacing, frame-rate conversion, and film judder compensation. There have been several block-based approaches to find true motion vectors by tracing minimum sum-of-absolute-difference values by considering spatial and temporal consistency. However, the algorithms cannot find robust motion vectors when the texture of objects is changed. To find the robust motion vectors in the region, a recursive vector selection scheme and an adaptive weighting parameter are proposed. Previous frame vectors are recursively averaged to be utilized for motion error region. The weighting parameter controls fidelity to input vectors and the recursively averaged ones, where the input vectors come from the conventional estimators. If the input vectors are not reliable... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=1882854 Thu, 16 Oct 2008 04:00:00 +0100 1882854 http://www.medworm.com/index.php?rid=1882853&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20134 This article proposes a new fragile watermarking scheme named bit-plane watermarking (BPW) which considers ways to improve coding efficiency whereas providing watermarking capability. Because of the use of the run-length coding strategy for embedding watermark information, the BPW not only verifies the authenticity and integrity of video streams, but also can recompress the bit streams for improving the compression ratio. To verify the effectiveness of this new concept, we select the MPEG-4 FGS as the platform for implementation. The watermark is embedded in the bit-plane blocks of MPEG-4 FGS enhancement layer bitstream, and the coefficient in each bit-plane block is automatically selected so that the run-length symbols can be reduced and the location of embedded bits is not required to me... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=1882853 Thu, 16 Oct 2008 04:00:00 +0100 1882853 http://www.medworm.com/index.php?rid=1882852&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20135 This article presents an image processing system that can work in hard real-time. Compared with systems that use the traditional multiprocessor architecture approach, this computer system takes advantage on recent technological advances and it is designed to work with a single processor PC under RTLinux. Its programming environment is similar to C programming language and it offers a friendly graphical user interface. The performance of the system is illustrated by means of experiments applied to visual guidance of mobile robots via velocity fields using a fixed high-speed camera. The experiments were carried out with a strict sampling frequency of 100 Hz. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 251-256, 2008; Published online in Wiley InterScience (www.interscience... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=1882852 Thu, 16 Oct 2008 04:00:00 +0100 1882852 http://www.medworm.com/index.php?rid=1882851&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20137 Superresolution is a procedure that produces a high-resolution image from a set of low-resolution images. Many of superresolution techniques are designed for optical cameras, which produce pixel values of well-defined uncertainty, while there are still various imaging modalities for which the uncertainty of the images is difficult to control. To construct a superresolution image from low-resolution images with varying uncertainty, one needs to keep track of the uncertainty values in addition to the pixel values. In this paper, we develop a probabilistic approach to superresolution to address the problem of varying uncertainty. As direct computation of the analytic solution for the superresolution problem is difficult, we suggest a novel algorithm for computing the approximate solution. As ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=1882851 Thu, 16 Oct 2008 04:00:00 +0100 1882851 http://www.medworm.com/index.php?rid=1882850&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20136 The neural network ensemble is a learning paradigm where a collection of neural networks is trained for the same task. Generally, the ensemble shows better generalization performance than a single neural network. In this article, a selective neural network ensemble is applied to gait recognition. The proposed method selects some neural network based on the minimization of generalization error. Since the selection rule is directly incorporated into the cost function, we can obtain adequate component networks to constitute an ensemble. Experiments are performed with the NLPR database to show the performance of the proposed algorithm. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 237-241, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). (Source: Int... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=1882850 Thu, 16 Oct 2008 04:00:00 +0100 1882850 http://www.medworm.com/index.php?rid=1882849&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20133 The inverse scattering of buried inhomogeneous biaxial dielectric cylinders coated on a conductor with known cross section is investigated. Dielectric cylinders with known cross section coated on a conductor of unknown permittivities are buried in one half space and scatter a group of unrelated waves incident from another half space where the scattered field is recorded. By proper arrangement of the various unrelated incident fields, the difficulties of ill-posedness and nonlinearity are circumvented, and the permittivity distribution can be reconstructed through simple matrix operations. The algorithm is based on the moment method and the unrelated illumination method. Numerical results are given to demonstrate the capability of the inverse algorithm. Good reconstruction is obtained both ... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=1882849 Thu, 16 Oct 2008 04:00:00 +0100 1882849 http://www.medworm.com/index.php?rid=1699637&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20146 Most of the existing graph edit distance (GED) algorithms require cost functions which are difficult to be defined exactly. In this article, we propose a cost function free algorithm for computing GED. It only depends on the distribution of nodes rather than node or edge attributes in graphs. Hidden Markov model (HMM) is employed to model the distribution of feature points and thus dissimilarity measure of graphs can be posed as distance of HMMs. A fast algorithm of Kullback-Leibler Distance, suitable for computing the distance between two probability models, is adopted to compute the distance of HMMs. Experimental results demonstrate that the proposed GED algorithm can characterize the structure variety of graphs effectively and is available for clustering and indexing images of both rigi... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=1699637 Mon, 11 Aug 2008 04:00:00 +0100 1699637 http://www.medworm.com/index.php?rid=1699636&cid=s_33640_37_f&fid=33640&url=http%3A%2F%2Fdx.doi.org%2F10.1002%252Fima.20149 Traditional content-based image retrieval (CBIR) systems use low-level features such as colors, shapes, and textures of images. Although, users make queries based on semantics, which are not easily related to such low-level characteristics. Recent works on CBIR confirm that researchers have been trying to map visual low-level characteristics and high-level semantics. The relation between low-level characteristics and image textual information has motivated this article which proposes a model for automatic classification and categorization of words associated to images. This proposal considers a self-organizing neural network architecture, which classifies textual information without previous learning. Experimental results compare the performance results of the text-based approach to an ima... International Journal of Imaging Systems and Technology journals http://www.medworm.com/rss/comments.php?id=1699636 Mon, 11 Aug 2008 04:00:00 +0100 1699636