MedWorm: Biomedical Engineering Research

Carrier Cooperation Can Reduce the Transmit Power in Parallel MIMO Broadcast Channels With Zero-Forcing

IEEE Transactions on Signal Processing — Sat, 18 May 2013 15:10:19 +0100

Even though parallel multiple-input multiple-output (MIMO) broadcast channels are known to be separable from an information theoretic point of view, performing separate encoding and decoding on each of the parallel channels has been shown to be potentially suboptimal in broadcast channels with linear transceivers. In this paper, we show that suboptimality of such a carrier-noncooperative transmission also occurs in broadcast channels with zero-forcing and quality of service constraints if time-sharing is not allowed. The proof is given by constructing a minimal example and identifying a rate tuple that is achievable using carrier-cooperative zero-forcing with a certain sum power but requires a higher sum power with carrier-noncooperative zero-forcing. This observation is of practical relev...

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Unsupervised Nosologic Imaging for Glioma Diagnosis

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:15 +0100

In this letter a novel approach to create nosologic images of the brain using magnetic resonance spectroscopic imaging (MRSI) data in an unsupervised way is presented. Different tissue patterns are identified from the MRSI data using nonnegative matrix factorization and are then coded as different primary colors (i.e. red, green, and blue) in an RGB image, so that mixed tissue regions are automatically visualized as mixtures of primary colors. The approach is useful in assisting glioma diagnosis, where several tissue patterns such as normal, tumor, and necrotic tissue can be present in the same voxel/spectrum. Error-maps based on linear least squares estimation are computed for each nosologic image to provide additional reliability information, which may help clinicians in decision making....

Call for papers ISBI'14

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:15 +0100

(Source: IEEE Transactions on Biomedical Engineering)

IEEE Transactions on Biomedical Engineering information for authors

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:15 +0100

(Source: IEEE Transactions on Biomedical Engineering)

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IEEE Transactions on Biomedical Engineering Associate Editors

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:15 +0100

(Source: IEEE Transactions on Biomedical Engineering)

Reduction of the Linear Reflex Gain Explained From the M1–M2 Refractory Period

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:14 +0100

Linear system identification methods combined with neuromechanical modeling enable the quantification of reflex gains from recorded joint angular perturbation, torque, and/or electromyography (EMG). However, the stretch reflex response as recorded by EMG consists of multiple consecutive activation volleys (M1 and M2 responses) separated by a period of reduced activity and is nonlinearly related to joint perturbation. The goal of this study is to assess to what extent linear assumptions hold when quantifying these reflexive responses. Series of ramp-and-hold angular perturbations with fixed velocity but different ramp durations (and, therefore, different amplitudes) were applied to the wrist joint of seven healthy volunteers. Evoked EMG responses were compared to the reflex response estimat...

Ultrasound Probe and Needle-Guide Calibration for Robotic Ultrasound Scanning and Needle Targeting

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:14 +0100

We report a calibration method for 2-D ultrasound probes using robotic manipulation and a planar calibration rig. Moreover, a needle guide that is attached to the probe is also calibrated for ultrasound-guided needle targeting. The method is applied to a transrectal ultrasound (TRUS) probe for robot-assisted prostate biopsy. Validation experiments include TRUS-guided needle targeting accuracy tests. This paper outlines the entire process from the calibration to image-guided targeting. Freehand TRUS-guided prostate biopsy is the primary method of diagnosing prostate cancer, with over 1.2 million procedures performed annually in the U.S. alone. However, freehand biopsy is a highly challenging procedure with subjective quality control. As such, biopsy devices are emerging to assist the physic...

An Approach to Rapid Calculation of Temperature Change in Tissue Using Spatial Filters to Approximate Effects of Thermal Conduction

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:14 +0100

We present an approach to performing rapid calculations of temperature within tissue by interleaving, at regular time intervals, 1) an analytical solution to the Pennes (or other desired) bioheat equation excluding the term for thermal conduction and 2) application of a spatial filter to approximate the effects of thermal conduction. Here, the basic approach is presented with attention to filter design. The method is applied to a few different cases relevant to magnetic resonance imaging, and results are compared to those from a full finite-difference (FD) implementation of the Pennes bioheat equation. It is seen that results of the proposed method are in reasonable agreement with those of the FD approach, with about 15% difference in the calculated maximum temperature increase, but...

Visualization and Analysis of the Deforming Piglet Femur and Hip Following Experimentally Induced Avascular Necrosis of the Femoral Head

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:14 +0100

Childhood avascular necrosis (AVN) of the femoral head leads to its progressive deformation and compensatory changes of the adjacent acetabulum. To simulate this disease for laboratory study, we used an AVN model of the hip in a skeletally immature piglet. The 3-D visualization and analysis of this piglet’s deforming femur and hip form the basis for this paper. In particular, the data for this analysis were generated via serial CT images of bilateral femurs and acetabula of a piglet at regular time intervals following experimental unilateral induction of femoral head AVN. The contralateral femur and acetabulum served as the control. We applied a shape analysis technique that effectively captured not only the temporal shape changes of the femurs and acetabula, but also their codepend...

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Modeling and Experimental Characterization of Propulsion of a Spiral-Type Microrobot for Medical Use in Gastrointestinal Tract

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:14 +0100

In this paper, a spiral-type medical robot based on an endoscopic capsule was propelled in a fluidic and tubular environment using electromagnetic actuation. Both modeling and experimental methods have been employed to characterize the propulsion of the robotic capsule. The experiments were performed not only in a simulated environment (vinyl tube filled with silicone oil) but also in a real small intestine. The effects of the spiral parameters including lead, spiral height, the number of spirals, and cross section of the spirals on the propulsion efficiency of the robot are investigated. Based on the transmission efficiency from rotation to translation as well as the balancing of the microrobot in operation, it is demonstrated that the robot with two spirals could provide the best propuls...

ECG Signal Quality During Arrhythmia and Its Application to False Alarm Reduction

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:13 +0100

An automated algorithm to assess electrocardiogram (ECG) quality for both normal and abnormal rhythms is presented for false arrhythmia alarm suppression of intensive care unit (ICU) monitors. A particular focus is given to the quality assessment of a wide variety of arrhythmias. Data from three databases were used: the Physionet Challenge 2011 dataset, the MIT-BIH arrhythmia database, and the MIMIC II database. The quality of more than 33 000 single-lead 10 s ECG segments were manually assessed and another 12 000 bad-quality single-lead ECG segments were generated using the Physionet noise stress test database. Signal quality indices (SQIs) were derived from the ECGs segments and used as the inputs to a support vector machine classifier with a Gaussian kernel. This cl...

Development of Surrogate Spinal Cords for the Evaluation of Electrode Arrays Used in Intraspinal Implants

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:13 +0100

We report the development of a surrogate spinal cord for evaluating the mechanical suitability of electrode arrays for intraspinal implants. The mechanical and interfacial properties of candidate materials (including silicone elastomers and gelatin hydrogels) for the surrogate cord were tested. The elastic modulus was characterized using dynamic mechanical analysis, and compared with values of actual human spinal cords from the literature. Forces required to indent the surrogate cords to specified depths were measured to obtain values under static conditions. Importantly, to quantify surface properties in addition to mechanical properties normally considered, interfacial frictional forces were measured by pulling a needle out of each cord at a controlled rate. The measured forces were then...

Noninvasive Biomagnetic Detection of Isolated Ischemic Bowel Segments

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:13 +0100

The slow wave activity was measured in the magnetoenterogram (MENG) of normal porcine subjects ( $N$ = 5) with segmental intestinal ischemia. The correlation changes in enteric slow wave activity were determined in MENG and serosal electromyograms (EMG). MENG recordings show significant changes in the frequency and power distribution of enteric slow-wave signals during segmental ischemia, and these changes agree with changes observed in the serosal EMG. There was a high degree of correlation between the frequency of the electrical activity recorded in MENG and in serosal EMG ($r = hbox{0.97}$). The percentage of power distributed in brady- and normoenteric frequency ranges exhibited significant segmental ischemic changes. Our results suggest that noninvasive MENG detects ischemic ch...

An Experimental Vestibular Neural Prosthesis: Design and Preliminary Results With Rhesus Monkeys Stimulated With Modulated Pulses

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:13 +0100

A vestibular neural prosthesis was designed on the basis of a cochlear implant for treatment of Meniere’s disease and other vestibular disorders. Computer control software was developed to generate patterned pulse stimuli for exploring optimal parameters to activate the vestibular nerve. Two rhesus monkeys were implanted with the prototype vestibular prosthesis and they were behaviorally evaluated post implantation surgery. Horizontal and vertical eye movement responses to patterned electrical pulse stimulations were collected on both monkeys. Pulse amplitude modulated (PAM) and pulse rate modulated (PRM) trains were applied to the lateral canal of each implanted animal. Robust slow-phase nystagmus responses following the PAM or PRM modulation pattern were observed in both implanted...

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Feature-Preserving Smoothing of Diffusion Weighted Images Using Nonstationarity Adaptive Filtering

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:13 +0100

Although promising for studying the microstructure of in vivo tissues, the performance and the potentiality of diffusion tensor magnetic resonance imaging are hampered by the presence of high-level noise in diffusion weighted (DW) images. This paper proposes a novel smoothing approach, called the nonstationarity adaptive filtering, which estimates the intensity of a pixel by averaging intensities in its adaptive homogeneous neighborhood. The latter is determined according to five constraints and spatiodirectional nonstationarity measure maps. The proposed approach is compared with an anisotropic diffusion method used in DW image smoothing. Experimental results on both synthetic and real human DW images show that the proposed method achieves a better compromise between the smoothness of hom...

The Alpha Band of the Resting Electroencephalogram Under Pulsed and Continuous Radio Frequency Exposures

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:13 +0100

The effect of GSM-like electromagnetic fields with the resting electroencephalogram (EEG) alpha band activity was investigated in a double-blind cross-over experimental paradigm, testing the hypothesis that pulsed but not continuous radio frequency (RF) exposure would affect alpha activity, and the hypothesis that GSM-like pulsed low frequency fields would affect alpha. Seventy-two healthy volunteers attended a single recording session where the eyes open resting EEG activity was recorded. Four exposure intervals were presented (sham, pulsed modulated RF, continuous RF, and pulsed low frequency) in a counterbalanced order where each exposure lasted for 20 min. Compared to sham, a suppression of the global alpha band activity was observed under the pulsed modulated RF exposure, and t...

A Fully Constrained Optimization Method for Time-Resolved Multispectral Fluorescence Lifetime Imaging Microscopy Data Unmixing

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:13 +0100

This paper presents a new unmixing methodology of multispectral fluorescence lifetime imaging microscopy (m-FLIM) data, in which the spectrum is defined as the combination of time-domain fluorescence decays at multiple emission wavelengths. The method is based on a quadratic constrained optimization (CO) algorithm that provides a closed-form solution under equality and inequality restrictions. In this paper, it is assumed that the time-resolved fluorescence spectrum profiles of the constituent components are linearly independent and known a priori. For comparison purposes, the standard least squares (LS) solution and two constrained versions nonnegativity constrained least squares (NCLS) and fully constrained least squares (FCLS) (Heinz and Chang, 2001) are also tested. Their performance w...

Optimization of Mechanical Ventilator Settings for Pulmonary Disease States

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:12 +0100

The selection of mechanical ventilator settings that ensure adequate oxygenation and carbon dioxide clearance while minimizing the risk of ventilator-associated lung injury (VALI) is a significant challenge for intensive-care clinicians. Current guidelines are largely based on previous experience combined with recommendations from a limited number of in vivo studies whose data are typically more applicable to populations than to individuals suffering from particular diseases of the lung. By combining validated computational models of pulmonary pathophysiology with global optimization algorithms, we generate in silico experiments to examine current practice and uncover optimal combinations of ventilator settings for individual patient and disease states. Formulating the problem as a multiob...

Ultrasound-Guided Characterization of Interstitial Ablated Tissue Using RF Time Series: Feasibility Study

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:12 +0100

This paper presents the results of a feasibility study to demonstrate the application of ultrasound RF time series imaging to accurately differentiate ablated and nonablated tissue. For 12 ex vivo and two in situ tissue samples, RF ultrasound signals are acquired prior to, and following, high-intensity ultrasound ablation. Spatial and temporal features of these signals are used to characterize ablated and nonablated tissue in a supervised-learning framework. In cross-validation evaluation, a subset of four features extracted from RF time series produce a classification accuracy of 84.5%, an area under ROC curve of 0.91 for ex vivo data, and an accuracy of 85% for in situ data. Ultrasound RF time series is a promising approach for characterizing ablated tissue. (Source: IEEE T...

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Motion of the Kidney Between Preoperative and Intraoperative Positioning

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:12 +0100

For many laparoscopic surgical procedures, the preoperative images are taken with the patient in a different position than that in which the surgery is performed. The organ shift between positions can affect surgical image guidance, as the organ shifts can complicate image registration. In particular, for partial nephrectomy, the standard clinical approach requires supine preoperative computed tomography, while the surgery is performed in the flank position. We studied ten subjects in both supine and flank positions. Rigid registration was used to determine the relative motion of the kidneys, using the spine as a pose-independent landmark. Our results showed that the kidney can move as much as 46.5 mm as a result of a supine-to-flank change in patient position, and rotate as much as...

A Reconfigurable Digital Filterbank for Hearing-Aid Systems With a Variety of Sound Wave Decomposition Plans

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:12 +0100

Current hearing-aid systems have fixed sound wave decomposition plans due to the use of fixed filterbanks, thus cannot provide enough flexibility for the compensation of different hearing impairment cases. In this paper, a reconfigurable filterbank that consists of a multiband-generation block and a subband-selection block is proposed. Different subbands can be produced according to the control parameters without changing the structure of the filterbank system. The use of interpolation, decimation, and frequency-response masking enables us to reduce the computational complexity by realizing the entire system with only three prototype filters. Reconfigurability of the proposed filterbank enables hearing-impaired people to customize hearing aids based on their own specific conditions to impr...

Effects of Robotic Knee Exoskeleton on Human Energy Expenditure

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:12 +0100

A number of studies discuss the design and control of various exoskeleton mechanisms, yet relatively few address the effect on the energy expenditure of the user. In this paper, we discuss the effect of a performance augmenting exoskeleton on the metabolic cost of an able-bodied user/pilot during periodic squatting. We investigated whether an exoskeleton device will significantly reduce the metabolic cost and what is the influence of the chosen device control strategy. By measuring oxygen consumption, minute ventilation, heart rate, blood oxygenation, and muscle EMG during 5-min squatting series, at one squat every 2 s, we show the effects of using a prototype robotic knee exoskeleton under three different noninvasive control approaches: gravity compensation approach, position-based...

Development of a Wireless Sensor for the Measurement of Chicken Blood Flow Using the Laser Doppler Blood Flow Meter Technique

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:12 +0100

Here, we report the development of an integrated laser Doppler blood flow micrometer for chickens. This sensor weighs only 18 g and is one of the smallest-sized blood flow meters, with no wired line, these are features necessary for attaching the sensor to the chicken. The structure of the sensor chip consists of two silicon cavities with a photo diode and a laser diode, which was achieved using the microelectromechanical systems technique, resulting in its small size and significantly low power consumption. In addition, we introduced an intermittent measuring arrangement in the measuring system to reduce power consumption and to enable the sensor to work longer. We were successfully able to measure chicken blood flow for five consecutive days, and discovered that chicken blood flow...

The Use of a Bone-Anchored Device as a Hard-Wired Conduit for Transmitting EMG Signals From Implanted Muscle Electrodes

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:12 +0100

The use of a bone-anchored device to transmit electrical signals from internalized muscle electrodes was studied in a sheep model. The bone-anchored device was used as a conduit for the passage of a wire connecting an internal epimysial electrode to an external signal-recording device. The bone-anchored device was inserted into an intact tibia and the electrode attached to the adjacent M. peroneus tertius. “Physiological” signals with low signal-to-noise ratios were successfully obtained over a 12-week period by walking the sheep on a treadmill. Reliable transmission of multiple muscle signals across the skin barrier is essential for providing intuitive, biomimetic upper limb prostheses. This technology has the potential to provide a better functional and reliable solution fo...

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Fold-Preserving Electronic Cleansing Using a Reconstruction Model Integrating Material Fractions and Structural Responses

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:11 +0100

In this paper, we propose an electronic cleansing method using a novel reconstruction model for removing tagged materials (TMs) in computed tomography (CT) images. To address the partial volume (PV) and pseudoenhancement (PEH) effects concurrently, material fractions and structural responses are integrated into a single reconstruction model. In our approach, colonic components including air, TM, an interface layer between air and TM, and an interface layer between soft-tissue (ST) and TM (IL$_{rm ST/TM}$ ) are first segmented. For each voxel in IL$_{rm ST/TM}$, the material fractions of ST and TM are derived using a two-material transition model, and the structural response to identify the folds submerged in the TM is calculated by the rut-enhancement function based on the eigenvalue signa...

Denoising MRI Using Spectral Subtraction

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:11 +0100

Improving the signal-to-noise-ratio (SNR) of magnetic resonance imaging (MRI) using denoising techniques could enhance their value, provided that signal statistics and image resolution are not compromised. Here, a new denoising method based on spectral subtraction of the measured noise power from each signal acquisition is presented. Spectral subtraction denoising (SSD) assumes no prior knowledge of the acquired signal and does not increase acquisition time. Whereas conventional denoising/filtering methods are compromised in parallel imaging by spatially dependent noise statistics, SSD is performed on signals acquired from each coil separately, prior to reconstruction. Using numerical simulations, we show that SSD can improve SNR by up to ∼45% in MRI reconstructed from both s...

Confidence-Based Rejection for Improved Pattern Recognition Myoelectric Control

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:11 +0100

This study describes a novel myoelectric control scheme that is capable of motion rejection. As an extension of the commonly used linear discriminant analysis (LDA), this system generates a confidence score for each decision, providing the ability to reject those with a score below a selected threshold. The thresholds are class-specific and affect only the rejection characteristics of the associated class. Furthermore, because the rejection stage is implemented using the outputs of the LDA, the active motion classification accuracy of the proposed system is shown to outperform that of the LDA for all values of rejection threshold. The proposed scheme was compared to a baseline LDA-based pattern recognition system using a real-time Fitts’ law-based target acquisition task. The use of...

Photon Efficiency Optimization in Time-Correlated Single Photon Counting Technique for Fluorescence Lifetime Imaging Systems

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:11 +0100

In this study, the loss of SNR is described by F- value as it is typically done in FLIM systems. This F-value describes the relation of the relative standard deviation in the estimated FLT to the relative standard deviation in FI measurements. Optimization of the F-value allows minimization of signal distortion, as well as shortening of the acquisition time for certain samples. We applied this method for Fluorescein, Rhodamine B, and Erythrosine fluorescent solutions that have different FLT values (4 ns, 1.67 ns, and 140 ps, respectively). (Source: IEEE Transactions on Biomedical Engineering)

Novel Bayesian Vectorcardiographic Loop Alignment for Improved Monitoring of ECG and Fetal Movement

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:11 +0100

The continuous analysis of electrocardiographic (ECG) signals is complicated by morphological variability in the ECG due to movement of the heart. By aligning vectorcardiographic loops, movement-induced ECG variations can be partly corrected for. Existing methods for loop alignment can account for loop rotation, scaling, and time delays, but they lack the possibility to include a priori information on any of these transformations, and they are unreliable in case of low-quality signals, such as fetal ECG signals. The inclusion of a priori information might aid in the robustness of loop alignment and is, hence, proposed in this paper. We provide a generic Bayesian framework to derive our loop alignment method. In this framework, existing methods can be readily derived as well, as a simplific...

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A Variational Surface Deformation and Subdivision-Based Modeling Framework for Noisy and Small -Furcated Tube-Like Structures

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:11 +0100

It is challenging to construct an accurate and smooth mesh for noisy and small $n$-furcated tube-like structures, such as arteries, veins, and pathological vessels, due to tiny vessel size, noise, $n$ -furcations, and irregular shapes of pathological vessels. We propose a framework by dividing the modeling process into mesh construction and mesh refinement. In the first step, we focus on mesh topological correctness, and just create an initial rough mesh for the $n$-furcated tube-like structures. In the second step, we propose a variational surface deformation method to push the initial mesh to structure boundaries for positional accuracy improvement. By iteratively solving Euler–Lagrange equations derived from the minimization of the shell and distance energies, the initial mesh ca...

An Impulse Radio Ultrawideband System for Contactless Noninvasive Respiratory Monitoring

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:10 +0100

We design a impulse radio ultrawideband radar monitoring system to track the chest wall movement of a human subject during respiration. Multiple sensors are placed at different locations to ensure that the backscattered signal could be detected by at least one sensor no matter which direction the human subject faces. We design a hidden Markov model to infer the subject facing direction and his or her chest movement. We compare the performance of our proposed scheme on $hbox{15}$ human volunteers with the medical gold standard using respiratory inductive plethysmography (RIP) belts, and show that on average, our estimation is over $hbox{81}%$ correlated with the measurements of a RIP belt system. Furthermore, in order to automatically differentiate between periods of normal and abnormal bre...

Flocking Multiple Microparticles With Automatically Controlled Optical Tweezers: Solutions and Experiments

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:10 +0100

This paper presents an efficient approach to achieve microparticles flocking with robotics and optical tweezers technologies. All particles trapped by optical tweezers can be automatically moved toward a predefined region without collision. The main contribution of this paper lies in the proposal of several solutions to the flocking manipulation of microparticles in microenvironments. First, a simple flocking controller is proposed to generate the desired positions and velocities for particles’ movement. Second, a velocity saturation method is implemented to prevent the desired velocities from exceeding a safe limit. Third, a two-layer control architecture is proposed for the motion control of optical tweezers. This architecture can help make many robotic manipulations achievable un...

Debye Parameter Extraction for Characterizing Interaction of Terahertz Radiation With Human Skin Tissue

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:10 +0100

This paper is concerned with parameter extraction for the double Debye model, which is used for analytically determining human skin permittivity. These parameters are thought to be the origin of contrast in terahertz (THz) images of skin cancer. The existing extraction methods could generate Debye models, which track their measurements accurately at frequencies higher than 1 THz but poorly at lower frequencies, where the majority of permittivity contrast between healthy and diseased skin tissues is actually observed. We propose a global optimization-based parameter extraction, which results in globally accurate tracking and thus supports the full validity of the Debye model for simulating human skin permittivity in the whole usable THz frequencies. Numerical results confirm viability of ou...

Mechatronic Design of a Fully Integrated Camera for Mini-Invasive Surgery

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:10 +0100

This paper describes the design features of an innovative fully integrated camera candidate for mini-invasive abdominal surgery with single port or transluminal access. The apparatus includes a CMOS imaging sensor, a light-emitting diode (LED)-based unit for scene illumination, a photodiode for luminance detection, an optical system designed according to the mechanical compensation paradigm, an actuation unit for enabling autofocus and optical zoom, and a control logics based on microcontroller. The bulk of the apparatus is characterized by a tubular shape with a diameter of 10 mm and a length of 35 mm. The optical system, composed of four lens groups, of which two are mobile, has a total length of 13.46 mm and an effective focal length ranging from 1.61 to 4.44 ...

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Front Cover

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:09 +0100

Presents the cover/table of contents for this issue of the periodical. (Source: IEEE Transactions on Biomedical Engineering)

IEEE Transactions on Biomedical Engineering publication information

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:09 +0100

(Source: IEEE Transactions on Biomedical Engineering)

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:09 +0100

Presents the table of contents for this issue of the periodical. (Source: IEEE Transactions on Biomedical Engineering)

Surgical Tool Alignment Guidance by Drawing Two Cross-Sectional Laser-Beam Planes

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:09 +0100

Conventional surgical navigation requires for surgeons to move their sight and conscious off the surgical field when checking surgical tool’s positions shown on the display panel. Since that takes high risks of surgical exposure possibilities to the patient’s body, we propose a novel method for guiding surgical tool position and orientation directly in the surgical field by a laser beam. In our navigation procedure, two cross-sectional planar laser beams are emitted from the two laser devices attached onto both sides of an optical localizer, and show surgical tool’s entry position on the patient’s body surface and its orientation on the side face of the surgical tool. In the experiments, our method gave the surgeons precise and accurate surgical tool adjusting a...

A Ridge Ensemble Empirical Mode Decomposition Approach to Clutter Rejection for Ultrasound Color Flow Imaging

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:09 +0100

In color flow imaging, it is a challenging work to accurately extract blood flow information from ultrasound Doppler echoes dominated by the strong clutter components. In this paper, we provide an in-depth analysis of ridge ensemble empirical mode decomposition (R-EEMD) and compare it with the conventional empirical mode decomposition (EMD) framework. R-EEMD facilitates nonuniform and trial-dependent weights obtained by an optimization procedure during ensemble combination and results in less decomposition errors when compared with the conventional ensemble empirical mode decomposition techniques. A theoretic result is then extended to demonstrate that R-EEMD has an ability to solve the mode mixing problem frequently encountered in EMD and improve the decomposition performance with adequat...

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Consciousness and Depth of Anesthesia Assessment Based on Bayesian Analysis of EEG Signals

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:09 +0100

This study applies Bayesian techniques to analyze EEG signals for the assessment of the consciousness and depth of anesthesia (DoA). This method takes the limiting large-sample normal distribution as posterior inferences to implement the Bayesian paradigm. The maximum a posterior (MAP) is applied to denoise the wavelet coefficients based on a shrinkage function. When the anesthesia states change from awake to light, moderate, and deep anesthesia, the MAP values increase gradually. Based on these changes, a new function $B_{rm DoA}$ is designed to assess the DoA. The new proposed method is evaluated using anesthetized EEG recordings and BIS data from 25 patients. The Bland–Alman plot is used to verify the agreement of $B_{rm DoA}$ and the popular BIS index. A correlation between $B_{...

A Comprehensive 3-D Framework for Automatic Quantification of Late Gadolinium Enhanced Cardiac Magnetic Resonance Images

IEEE Transactions on Biomedical Engineering — Sat, 18 May 2013 15:10:09 +0100

Late gadolinium enhanced (LGE) cardiac magnetic resonance (CMR) can directly visualize nonviable myocardium with hyperenhanced intensities with respect to normal myocardium. For heart attack patients, it is crucial to facilitate the decision of appropriate therapy by analyzing and quantifying their LGE CMR images. To achieve accurate quantification, LGE CMR images need to be processed in two steps: segmentation of the myocardium followed by classification of infarcts within the segmented myocardium. However, automatic segmentation is difficult usually due to the intensity heterogeneity of the myocardium and intensity similarity between the infarcts and blood pool. Besides, the slices of an LGE CMR dataset often suffer from spatial and intensity distortions, causing further difficulties in ...

Classification of emotional States from electrocardiogram signals: a non-linear approach based on hurst

BioMedical Engineering OnLine — Thu, 16 May 2013 04:00:00 +0100

Conclusions: The results indicate that the combination of non-linear analysis and HOS tend to retain and capture the finer emotional changes that can be seen in healthy ECG data. This work can be further fine tuned to develop a real time system. (Source: BioMedical Engineering OnLine)

Performance assessment in brain-computer interface-based augmentative and alternative communication

BioMedical Engineering OnLine — Thu, 16 May 2013 04:00:00 +0100

A large number of incommensurable metrics are currently used to report the performance of brain-computer interfaces (BCI) used for augmentative and alterative communication (AAC). The lack of standard metrics precludes the comparison of different BCI-based AAC systems, hindering rapid growth and development of this technology. This paper presents a review of the metrics that have been used to report performance of BCIs used for AAC from January 2005 to January 2012. We distinguish between Level 1 metrics used to report performance at the output of the BCI Control Module, which translates brain signals into logical control output, and Level 2 metrics at the Selection Enhancement Module, which translates logical control to semantic control. We recommend that: (1) the commensurate metrics Mut...

Nanoparticle Network Acts As An Artificial Pancreas

NanoFocus — Tue, 14 May 2013 05:03:58 +0100

Biomedical Engineering: Material releases enough insulin to maintain normal blood sugar levels in diabetic mice for at least 10 days (Source: NanoFocus)

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A hybrid approach to the simultaneous eliminating of power-line interference and associated ringing artifacts in electrocardiograms

BioMedical Engineering OnLine — Tue, 14 May 2013 04:00:00 +0100

Conclusions: Overall, a significant reduction in signal distortion is demonstrated. These test results indicate that the newly proposed approach outperforms the traditional method assessed on both the artificial and clinical ECGs and suggest it could be of practical use for clinicians in the future. (Source: BioMedical Engineering OnLine)

Editorial Board

Medical Engineering and Physics — Tue, 14 May 2013 02:10:04 +0100

(Source: Medical Engineering and Physics)

Detecting fixation on a target using time-frequency distributions of a retinal birefringence scanning signal

BioMedical Engineering OnLine — Mon, 13 May 2013 04:00:00 +0100

Conclusion: Joint time-frequency analysis is a powerful tool in the detection of eye alignment, even in a noisy environment. The method is applicable to similar situations, where short-lasting diagnostic events need to be detected in time series acquired by means of scanning some substrate along a specific path. (Source: BioMedical Engineering OnLine)

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Methods of measuring the iridocorneal angle in tomographic images of the anterior segment of the eye

BioMedical Engineering OnLine — Fri, 10 May 2013 04:00:00 +0100

Conclusions: The study proved that the proposed method of measuring the minimum distance between the iris and the cornea within the adopted area is the most effective in the classification of the iridocorneal angle in patients with a high degree of pathology of all the compared measurement methods based on tomographic images. However, it requires fully automated measurement. (Source: BioMedical Engineering OnLine)

Volumetric three-dimensional intravascular ultrasound visualization using shape-based nonlinear interpolation

BioMedical Engineering OnLine — Tue, 07 May 2013 04:00:00 +0100

Conclusions: This novel 3D IVUS visualization strategy has the potential to improve ultrasound imaging of vascular structure information, particularly atheroma determination. Improved volumetric 3D visualization with accurate acoustic backscatter information can help with ultrasound molecular imaging of atheroma component distribution. (Source: BioMedical Engineering OnLine)

Editorial Board

Medical Engineering and Physics — Wed, 01 May 2013 04:00:00 +0100

(Source: Medical Engineering and Physics)

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

Presents the cover/table of contents for this issue of the periodical. (Source: IEE Transactions on Medical Imaging)

IEEE Transactions on Medical Imaging publication information

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

Provides a listing of current staff, committee members and society officers. (Source: IEE Transactions on Medical Imaging)

Fast Joint Detection-Estimation of Evoked Brain Activity in Event-Related fMRI Using a Variational Approach

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

In standard within-subject analyses of event-related functional magnetic resonance imaging (fMRI) data, two steps are usually performed separately: detection of brain activity and estimation of the hemodynamic response. Because these two steps are inherently linked, we adopt the so-called region-based joint detection-estimation (JDE) framework that addresses this joint issue using a multivariate inference for detection and estimation. JDE is built by making use of a regional bilinear generative model of the BOLD response and constraining the parameter estimation by physiological priors using temporal and spatial information in a Markovian model. In contrast to previous works that use Markov Chain Monte Carlo (MCMC) techniques to sample the resulting intractable posterior distribution, we r...

Dynamic 3-D Visualization of Vocal Tract Shaping During Speech

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

We present a novel method for the creation of 3-D dynamic movies of vocal tract shaping based on the acquisition of 2-D dynamic data from parallel slices and temporal alignment of the image sequences using audio information. Multiple sagittal 2-D real-time movies with synchronized audio recordings are acquired for English vowel-consonant-vowel stimuli /ala/, /a$hbox{ ?? }$a/, /asa/, and /a$! smallint !$a/. Audio data are aligned using mel-frequency cepstral coefficients (MFCC) extracted from windowed intervals of the speech signal. Sagittal image sequences acquired from all slices are then aligned using dynamic time warping (DTW). The aligned image sequences enable dynamic 3-D visualization by creating synthesized movies of the moving airway in the coronal planes, visualizing desired tissu...

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Detection and Analysis of Irregular Streaks in Dermoscopic Images of Skin Lesions

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

Irregular streaks are important clues for Melanoma (a potentially fatal form of skin cancer) diagnosis using dermoscopy images. This paper extends our previous algorithm to identify the absence or presence of streaks in a skin lesions, by further analyzing the appearance of detected streak lines, and performing a three-way classification for streaks, Absent, Regular, and Irregular, in a pigmented skin lesion. In addition, the directional pattern of detected lines is analyzed to extract their orientation features in order to detect the underlying pattern. The method uses a graphical representation to model the geometric pattern of valid streaks and the distribution and coverage of the structure. Using these proposed features of the valid streaks along with the color and texture features of ...

Quantitative Analysis of Cardiac Tissue Including Fibroblasts Using Three-Dimensional Confocal Microscopy and Image Reconstruction: Towards a Basis for Electrophysiological Modeling

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

Electrophysiological modeling of cardiac tissue is commonly based on functional and structural properties measured in experiments. Our knowledge of these properties is incomplete, in particular their remodeling in disease. Here, we introduce a methodology for quantitative tissue characterization based on fluorescent labeling, 3-D scanning confocal microscopy, image processing and reconstruction of tissue micro-structure at sub-micrometer resolution. We applied this methodology to normal rabbit ventricular tissue and tissue from hearts with myocardial infarction. Our analysis revealed that the volume fraction of fibroblasts increased from $4.83pm 0.42%$ (mean $pm$ standard deviation) in normal tissue up to $6.51pm 0.38%$ in myocardium from infarcted hearts. The myocyte volume fraction decre...

Model-Driven Harmonic Parameterization of the Cortical Surface: HIP-HOP

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

In the context of inter subject brain surface matching, we present a parameterization of the cortical surface constrained by a model of cortical organization. The parameterization is defined via an harmonic mapping of each hemisphere surface to a rectangular planar domain that integrates a representation of the model. As opposed to previous landmark-based registration methods we do not match folds between individuals but instead optimize the fit between cortical sulci and specific iso-coordinate axis in the model. This strategy overcomes some limitation to sulcus-based registration techniques such as topological variability in sulcal landmarks across subjects. Experiments on 62 subjects with manually traced sulci are presented and compared with the result of the Freesurfer software. The ev...

Application of Radial Ray Based Segmentation to Cervical Lymph Nodes in CT Images

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

The 3D-segmentation of lymph nodes in computed tomography images is required for staging and disease progression monitoring. Major challenges are shape and size variance, as well as low contrast, image noise, and pathologies. In this paper, radial ray based segmentation is applied to lymph nodes. From a seed point, rays are cast into all directions and an optimization technique determines a radius for each ray based on image appearance and shape knowledge. Lymph node specific appearance cost functions are introduced and their optimal parameters are determined. For the first time, the resulting segmentation accuracy of different appearance cost functions and optimization strategies is compared. Further contributions are extensions to reduce the dependency on the seed point, to support a lar...

A Piecewise Monotone Subgradient Algorithm for Accurate -TV Based Registration of Physical Slices With Discontinuities in Microscopy

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

Image registration tasks are often formulated in terms of minimization of a functional consisting of a data fidelity term penalizing the mismatch between the reference and the target image, and a term enforcing smoothness of shift between neighboring pairs of pixels (a min-sum problem). Most methods for deformable image registration use some form of interpolation between matching control points. The interpolation makes it impossible to account for isolated discontinuities in the deformation field that may appear, e.g., when a physical slice of a microscopy specimen is ruptured by the cutting tool. For registration of neighboring physical slices of microscopy specimens with discontinuities, Janácek proposed an ${rm L}^{1}$-distance data fidelity term and a total variation (TV) smooth...

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Registration of Coronary CTA and Monoplane X-Ray Angiography

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

A method for registering preoperative $3{rm D}+{rm t}$ coronary CTA with intraoperative monoplane $2{rm D}+{rm t}$ X-ray angiography images is proposed to improve image guidance during minimally invasive coronary interventions. The method uses a patient-specific dynamic coronary model, which is derived from the CTA scan by centerline extraction and motion estimation. The dynamic coronary model is registered with the $2{rm D}+{rm t}$ X-ray sequence, considering multiple X-ray time points concurrently, while taking breathing induced motion into account. Evaluation was performed on 26 datasets of 17 patients by comparing projected model centerlines with manually annotated centerlines in the X-ray images. The proposed $3{rm D}+{rm t}/2{rm D}+{rm t}$ registration method performed better than a ...

Sparse Signal Recovery Methods for Multiplexing PET Detector Readout

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

Nuclear medicine imaging detectors are commonly multiplexed to reduce the number of readout channels. Because the underlying detector signals have a sparse representation, sparse recovery methods such as compressed sensing may be used to develop new multiplexing schemes. Random methods may be used to create sensing matrices that satisfy the restricted isometry property. However, the restricted isometry property provides little guidance for developing multiplexing networks with good signal-to-noise recovery capability. In this work, we describe compressed sensing using a maximum likelihood framework and develop a new method for constructing multiplexing (sensing) matrices that can recover signals more accurately in a mean square error sense compared to sensing matrices constructed by random...

A General Framework for Context-Specific Image Segmentation Using Reinforcement Learning

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

This paper presents an online reinforcement learning framework for medical image segmentation. The concept of context-specific segmentation is introduced such that the model is adaptive not only to a defined objective function but also to the user's intention and prior knowledge. Based on this concept, a general segmentation framework using reinforcement learning is proposed, which can assimilate specific user intention and behavior seamlessly in the background. The method is able to establish an implicit model for a large state-action space and generalizable to different image contents or segmentation requirements based on learning in situ. In order to demonstrate the practical value of the method, example applications of the technique to four different segmentation problems are presented...

Distributed MLEM: An Iterative Tomographic Image Reconstruction Algorithm for Distributed Memory Architectures

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

The processing speed for positron emission tomography (PET) image reconstruction has been greatly improved in recent years by simply dividing the workload to multiple processors of a graphics processing unit (GPU). However, if this strategy is generalized to a multi-GPU cluster, the processing speed does not improve linearly with the number of GPUs. This is because large data transfer is required between the GPUs after each iteration, effectively reducing the parallelism. This paper proposes a novel approach to reformulate the maximum likelihood expectation maximization (MLEM) algorithm so that it can scale up to many GPU nodes with less frequent inter-node communication. While being mathematically different, the new algorithm maximizes the same convex likelihood function as MLEM, thus con...

2013 ieee nss/mic/rtsd

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

Describes the above-named upcoming conference event. May include topics to be covered or calls for papers. (Source: IEE Transactions on Medical Imaging)

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IEEE Transactions on Medical Imaging information for authors

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

Provides instructions and guidelines to prospective authors who wish to submit manuscripts. (Source: IEE Transactions on Medical Imaging)

[Blank page - back cover]

IEE Transactions on Medical Imaging — Wed, 01 May 2013 04:00:00 +0100

This page or pages intentionally left blank. (Source: IEE Transactions on Medical Imaging)

Neurovascular coupling: in vivo optical techniques for functional brain imaging

BioMedical Engineering OnLine — Tue, 30 Apr 2013 04:00:00 +0100

Optical imaging techniques reflect different biochemical processes in the brain, which is closely related with neural activity. Scientists and clinicians employ a variety of optical imaging technologies to visualize and study the relationship between neurons, glial cells and blood vessels. In this paper, we present an overview of the current optical approaches used for the in vivo imaging of neurovascular coupling events in small animal models. These techniques include 2-photon microscopy, laser speckle contrast imaging (LSCI), voltage-sensitive dye imaging (VSDi), functional photoacoustic microscopy (fPAM), functional near-infrared spectroscopy imaging (fNIRS) and multimodal imaging techniques. The basic principles of each technique are described in detail, followed by examples of current...

Detection of the valvular split within the second heart sound using the reassigned smoothed pseudo Wigner-Ville distribution

BioMedical Engineering OnLine — Tue, 30 Apr 2013 04:00:00 +0100

Background In this paper, we developed a novel algorithm to detect the valvular split between the aortic and pulmonary components in the second heart sound which is a valuable medical information.Methods The algorithm is based on the Reassigned smoothed pseudo Wigner--Ville distribution which is a modified time--frequency distribution of the Wigner--Ville distribution. A preprocessing amplitude recovery procedure is carried out on the analysed heart sound to improve the readability of the time--frequency representation. The simulated S2 heart sounds were generated by an overlapping frequency modulated chirp--based model at different valvular split durations.Results Simulated and real heart sounds are processed to highlight the performance of the proposed approach. The algorithm is also val...

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In vivo MRI-based simulation of fatigue process: a possible trigger for human carotid atherosclerotic plaque rupture

BioMedical Engineering OnLine — Tue, 23 Apr 2013 04:00:00 +0100

Conclusion: Fatigue process seems to explain the development of cracks in FC, which ultimately lead to plaque rupture. (Source: BioMedical Engineering OnLine)

Bone formation in rabbit cancellous bone explant culture model is enhanced by mechanical load

BioMedical Engineering OnLine — Fri, 19 Apr 2013 04:00:00 +0100

Background: When studying and designing an artificial bone in vitro with similar features and functionality of natural bone by tissue engineering technology, the culturing environment, especially the mechanical environment is supposed to be an important factor, because a suitable mechanical environment in vitro may improve the adaptability of the planted-in tissue engineering bone in the body. Unfortunately, up to now, the relationship between mechanical stimuli and natural bone growth has not yet been precisely determined, and it is so imperative for a prior study on effect of mechanical loading on growth of the natural bone cultured in vitro. Methods: Under sterile conditions, explant models of rabbit cancellous bone with 3 mm in thickness and 8 mm in diameter were prepared and cultured ...

Review of "orthopaedic biomechanics" edited by Beth A. Winkelstein

BioMedical Engineering OnLine — Thu, 18 Apr 2013 04:00:00 +0100

Orthopaedic Biomechanics was released in 2012 and edited by Beth A. Winkelstein, PhD. The list price of the book ($179.95) is comparable with similar books published in this field. This text is intended for both the novice and established researcher working the field of orthopaedic biomechanics. However, this book assumes that the reader has some basic knowledge about biomechanics, finite element modeling, and biomaterials used in orthopedic surgery. Composed of twenty-one chapters with approximately 3,000 references, "Orthopaedic Biomechanics" provides an exhaustive literature review of the most current published data in orthopaedic biomechanical engineering. This work focuses on the vast and complex nature of the field of orthopedic biomechanics that challenges both researchers and clini...

Review of ¿orthopaedic biomechanics¿ edited by Beth A. Winkelstein

BioMedical Engineering OnLine — Thu, 18 Apr 2013 04:00:00 +0100

This article is a review of the book “orthopaedic biomechanics” edited by Beth A. Winkelstein. This book (hardcover) was published by CRC Press, Taylor & Francis Group, FL in 2012. The contents of the book and its relevance to orthopedic research or practice is discussed in this invited review. (Source: BioMedical Engineering OnLine)

Motor recovery monitoring using acceleration measurements in post acute stroke patients

BioMedical Engineering OnLine — Tue, 16 Apr 2013 04:00:00 +0100

Conclusion: A wireless accelerometer based 'hot stroke' monitoring system is developed to monitor the motor recovery in acute-stroke patients. It has been shown to monitor stroke patients continuously, which has not been possible so far with high reliability. (Source: BioMedical Engineering OnLine)

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Dependence of model-based RSA accuracy on higher and lower implant surface model quality

BioMedical Engineering OnLine — Tue, 16 Apr 2013 04:00:00 +0100

Conclusion: The data suggest that the application of lower resolution RE models for MBRSA is a viable alternative method for the in vivo measurement of implant migration, in particular for implants with non symmetrical geometries (total knee arthroplasty). Implants with larger length to width aspect ratio (total hip arthroplasty) may require high resolution RE models in order to achieve acceptable accuracy. Conversely, for some axis the bias for translation are clearly worse for translation, and are marginally better for rotations using the lower resolution RE models instead of the higher ones. However, performed box plots ranges were well within what has been reported in the literature. The observed lower accuracy and precision of the measurements for hip stem components for rotations abo...

IEEE Transactions on Signal Processing publication information

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

(Source: IEEE Transactions on Signal Processing)

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

(Source: IEEE Transactions on Signal Processing)

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Time-of-Arrival Estimation Based on Information Theoretic Criteria

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

The possibility to accurately localize tags by using wireless techniques is of great importance for several emerging applications in the Internet of Things. Precise ranging can be obtained with ultra wideband (UWB) impulse radio (IR) systems, where short impulses are transmitted, and their time-of-arrival (ToA) is estimated at the receiver. Due to the presence of noise and multipath, the estimator has the difficult task of discriminating the time intervals where the received waveform is due to noise only, by those where there are also signal components. Common low-complexity methods use an energy detector (ED), whose output is compared with a threshold, to discriminate the time intervals containing noise only from those containing signal plus noise. Optimal threshold design for these metho...

Wavelet Denoising Based on the MAP Estimation Using the BKF Prior With Application to Images and EEG Signals

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This paper presents a novel nonparametric Bayesian estimator for signal and image denoising in the wavelet domain. This approach uses a prior model of the wavelet coefficients designed to capture the sparseness of the wavelet expansion. A new family of Bessel K Form (BKF) densities are designed to fit the observed histograms, so as to provide a probabilistic model for the marginal densities of the wavelet coefficients. This paper first shows how the BKF prior can characterize images belonging to Besov spaces. Then, a new hyper-parameters estimator based on EM algorithm is designed to estimate the parameters of the BKF density; and, it is compared with a cumulants-based estimator. Exploiting this prior model, another novel contribution is to design a Bayesian denoiser based on the Maximum A...

Space-Time-Frequency (STF) MIMO Communication Systems With Blind Receiver Based on a Generalized PARATUCK2 Model

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

In this paper, we first propose a generalized fourth-order PARATUCK2 tensor model for multiple-input multiple-output (MIMO) communication systems with space-time-frequency (STF) spreading-multiplexing. The core of the proposed PARATUCK2 model is composed of two third-order interaction tensors that define a joint time and frequency allocation of the data streams to the transmit antennas, thus allowing to adjust the multiplexing degree and spreading redundancy in three domains: space (transmit antennas), time (blocks) and frequency (subcarriers). Then, we investigate the identifiability of the PARATUCK2-STF MIMO system by deriving sufficient conditions which are translated into design recommendations for the STF allocation structure. In particular, essential uniqueness is discussed by interp...

Improvement of TDOA Position Fixing Using the Likelihood Curvature

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

A conventional multilateration is a two-step process where, in the first step the time difference of arrivals (TDOA) of a signal at multiple sensors are estimated, and in the second step, these TDOAs are used in some position fixing technique to estimate the location of an emitter. Several estimators have been proposed over the years for the estimation of the TDOAs. Many techniques have been proposed for position fixing as well. Much of the research on position fixing has been focused on obtaining a simplified closed form solution. For the unknown deterministic signal model, Stein had derived the maximum-likelihood estimator (MLE) for the TDOA between two sensors, which is the peak location of the cross-correlation function. Since the asymptotic variance of an MLE approaches the Cramer-Rao...

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Low-Complexity DOA Estimation Based on Compressed MUSIC and Its Performance Analysis

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This paper presents a new computationally efficient method for direction-of-arrival (DOA) estimation with arbitrary arrays. The total angular field-of-view is first divided into several small sectors and the original noise subspace exploited by the multiple signal classification (MUSIC) algorithm is mapped from one sector to the other sectors by a Hadarmard product transformation. This transformation gives a new noise-like subspace cluster (NLSC), whose intersection is found to be simultaneously orthogonal to the steering vectors associated with the true DOAs and several virtual DOAs. Based on such a multiple orthogonality, a novel compressed MUSIC (C-MUSIC) spatial spectrum at hand is derived. Unlike MUSIC with tremendous spectral search, C-MUSIC involves a limited search over only one se...

Efficient Soft Decision Fusion Rule in Cooperative Spectrum Sensing

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

In cognitive radio (CR), the soft decision fusion (SDF) rule plays a critical role in cooperative spectrum sensing (CSS). However, the computational cost on obtaining efficient SDF rule becomes infeasible even with a small number of cooperative users. In this paper, the efficiency of SDF rule in inhomogeneous background is studied from the perspective of quantization theory. We formulate the calculation of sensing performance including the probabilities of detection and false alarm when regarding both i) the quantization impact and ii) the inhomogeneous background, and then conclude a condition under which the sensing performance can be calculated by the fast Fourier transform (FFT). Based on this condition, two novel quantization schemes with two optimization methods are proposed to guara...

Modeling and Estimation of Covariance of Replicated Modulated Cyclical Time Series

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This paper introduces the novel class of modulated cyclostationary processes, a class of nonstationary processes exhibiting frequency coupling, and proposes a method of their estimation from repeated trials. Cyclostationary processes also exhibit frequency correlation but have Loève spectra whose support lies only on parallel lines in the dual-frequency plane. Such extremely sparse structure does not adequately represent many biological processes. Thus, we propose a model that, in the time domain, modulates the covariance of cyclostationary processes and consequently broadens their frequency support in the dual-frequency plane. The spectra and the cross-coherence of the proposed modulated cyclostationary process are first estimated using multitaper methods. A shrinkage procedure is ...

Robustness Analysis of Spatial Time-Frequency Distributions Based on the Influence Function

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

Standard spatial time-frequency distribution (STFD) estimators, derived based on the Gaussian noise assumption, are known to have poor performance in the case of impulsive noise. Recently, different STFD estimators have been proposed, which, based on simulations, are claimed to be robust. In this paper, we provide an influence function robustness analysis of STFD estimators. We derive the influence functions for the asymptotic and for the finite-sample case and study robustness of the standard, as well as for some recently proposed robust STFD estimators. The empirical influence function gives practitioners a simple way to pre-select STFD estimators for their scenario. Our analysis confirms that, unlike for the standard estimator, the proposed robust estimators yield a bounded influence fu...

The Performance of a Matched Subspace Detector That Uses Subspaces Estimated From Finite, Noisy, Training Data

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

We analyze the performance of a matched subspace detector (MSD) where the test signal vector is assumed to reside in an unknown, low-rank $k$ subspace that must be estimated from finite, noisy, signal-bearing training data. Under both a stochastic and deterministic model for the test vector, subspace estimation errors due to limited training data degrade the performance of the standard plug-in detector, relative to that of an oracle detector. To avoid some of this performance loss, we utilize and extend recent results from random matrix theory (RMT) that precisely quantify the quality of the subspace estimate as a function of the eigen-SNR, dimensionality of the system, and the number of training samples. We exploit this knowledge of the subspace estimation accuracy to derive from first-pr...

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Cramér-Rao-Induced Bounds for CANDECOMP/PARAFAC Tensor Decomposition

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This paper presents a Cramér-Rao lower bound (CRLB) on the variance of unbiased estimates of factor matrices in Canonical Polyadic (CP) or CANDECOMP/PARAFAC (CP) decompositions of a tensor from noisy observations, (i.e., the tensor plus a random Gaussian i.i.d. tensor). A novel expression is derived for a bound on the mean square angular error of factors along a selected dimension of a tensor of an arbitrary dimension. The expression needs less operations for computing the bound, $O(NR^{6})$, than the best existing state-of-the art algorithm, $O(N^{3}R^{6})$ operations, where $N$ and $R$ are the tensor order and the tensor rank. Insightful expressions are derived for tensors of rank 1 and rank 2 of arbitrary dimension and for tensors of arbitrary dimension and rank, where two factor...

Performance of the Delsarte-Goethals Frame on Clustered Sparse Vectors

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

The Delsarte-Goethals frame (DGF) has been proposed for deterministic compressive sensing of sparse and compressible signals. Results in compressive sensing theory show that the DGF enables successful recovery of an overwhelming majority of sufficiently sparse signals. However, these results do not give a characterization of the sparse vectors for which the recovery procedure fails. In this paper, we present a formal analysis of the DGF that highlights the presence of clustered sparse vectors within its null space. This in turn implies that sparse recovery performance is diminished for sparse vectors that have their nonzero entries clustered together. Such clustered structure is present in compressive imaging applications, where commonly-used raster scannings of 2-D discrete wavelet transf...

Extension of SBL Algorithms for the Recovery of Block Sparse Signals With Intra-Block Correlation

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

We examine the recovery of block sparse signals and extend the recovery framework in two important directions; one by exploiting the signals' intra-block correlation and the other by generalizing the signals' block structure. We propose two families of algorithms based on the framework of block sparse Bayesian learning (BSBL). One family, directly derived from the BSBL framework, require knowledge of the block structure. Another family, derived from an expanded BSBL framework, are based on a weaker assumption on the block structure, and can be used when the block structure is completely unknown. Using these algorithms, we show that exploiting intra-block correlation is very helpful in improving recovery performance. These algorithms also shed light on how to modify existing algorithms or d...

Projection Design for Statistical Compressive Sensing: A Tight Frame Based Approach

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

In this paper, we develop a framework to design sensing matrices for compressive sensing applications that lead to good mean squared error (MSE) performance subject to sensing cost constraints. By capitalizing on the MSE of the oracle estimator, whose performance has been shown to act as a benchmark to the performance of standard sparse recovery algorithms, we use the fact that a Parseval tight frame is the closest design - in the Frobenius norm sense - to the solution of a convex relaxation of the optimization problem that relates to the minimization of the MSE of the oracleestimator with respect to the equivalent sensing matrix, subject to sensing energy constraints. Based on this result, we then propose two sensing matrix designs that exhibit two key properties: i) the designs are close...

Maximally Robust Capon Beamformer

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

The standard Capon beamformer (SCB) achieves the maximum output signal-to-interference-plus-noise ratio in the error-free case. However, estimation errors of the signal steering vector and the array covariance matrix can result in severe performance deteriorations of the SCB, especially if the training data contains the desired signal component. A popular technique to improve the robustness against model errors is to compute the Capon beamformer with the maximum output power, considering an uncertainty set for the signal steering vector. However, maximizing the total beamformer output power may result in an insufficient suppression of interferers and noise. As an alternative approach to mitigate the detrimental effect of model errors, we propose to compute the Capon beamformer with the min...

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On Cyclostationarity Based Spectrum Sensing Under Uncertain Gaussian Noise

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

Detection of cyclostationary primary user (PU) signals in colored Gaussian noise for cognitive radio systems is considered based on looking for single or multiple cycle frequencies at single or multiple time lags in the cyclic autocorrelation function (CAF) of the noisy PU signal. We explicitly exploit the knowledge that under the null hypothesis of PU signal absent, the measurements originate from possible colored Gaussian noise with unknown correlation function. Our formulation allows us to simplify the spectrum sensing detector and obviates the need for estimating an unwieldy covariance matrix needed in some prior works. We consider both single and multiple antenna receivers, and both nonconjugate and conjugate CAFs. A performance analysis of the proposed detector is carried out. Suppor...

Learning Incoherent Dictionaries for Sparse Approximation Using Iterative Projections and Rotations

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

This article deals with learning dictionaries for sparse approximation whose atoms are both adapted to a training set of signals and mutually incoherent. To meet this objective, we employ a dictionary learning scheme consisting of sparse approximation followed by dictionary update and we add to the latter a decorrelation step in order to reach a target mutual coherence level. This step is accomplished by an iterative projection method complemented by a rotation of the dictionary. Experiments on musical audio data and a comparison with the method of optimal coherence-constrained directions (mocod) and the incoherent k-svd (ink-svd) illustrate that the proposed algorithm can learn dictionaries that exhibit a low mutual coherence while providing a sparse approximation with better signal-to-no...

The Feasibility Conditions for Interference Alignment in MIMO Networks

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

Interference alignment (IA) has attracted great attention in the last few years for its breakthrough performance in interference networks. However, despite the numerous works dedicated to IA, the feasibility conditions of IA remains unclear for most network topologies. The IA feasibility analysis is challenging as the IA constraints are sets of high-degree polynomials, for which no systematic tool to analyze the solvability conditions exists. In this work, by developing a new mathematical framework that maps the solvability of sets of polynomial equations to the linear independence of their first-order terms, we propose a sufficient condition that applies to MIMO interference networks with general configurations. We have further proved that this sufficient condition coincides with the nece...

FastICA Algorithm: Five Criteria for the Optimal Choice of the Nonlinearity Function

IEEE Transactions on Signal Processing — Fri, 12 Apr 2013 14:10:09 +0100

Using an infinite sample, the contrast function and the FastICA algorithm are deterministic. In the practical case, we have only a finite sample. Then the contrast function and the FastICA algorithm become estimators of the deterministic case. This paper provides a unified study of the deflation FastICA algorithm assuming a finite or an infinite sample. We consider four random probability distributions based on the finite sample, and construct four FastICA estimators. We show that under mild conditions, each of these estimators are equal to a local minimizer of the contrast function with respect to the underlying random probability distribution. Making use of the existing results of M-estimators, we give a rigorous analysis of the asymptotic errors of FastICA estimators. We derive five cri...

MedWorm: Biomedical Engineering Research

Carrier Cooperation Can Reduce the Transmit Power in Parallel MIMO Broadcast Channels With Zero-Forcing

Unsupervised Nosologic Imaging for Glioma Diagnosis

Call for papers ISBI'14

IEEE Transactions on Biomedical Engineering information for authors

IEEE Transactions on Biomedical Engineering Associate Editors

Reduction of the Linear Reflex Gain Explained From the M1–M2 Refractory Period

Ultrasound Probe and Needle-Guide Calibration for Robotic Ultrasound Scanning and Needle Targeting

An Approach to Rapid Calculation of Temperature Change in Tissue Using Spatial Filters to Approximate Effects of Thermal Conduction

Visualization and Analysis of the Deforming Piglet Femur and Hip Following Experimentally Induced Avascular Necrosis of the Femoral Head

Modeling and Experimental Characterization of Propulsion of a Spiral-Type Microrobot for Medical Use in Gastrointestinal Tract

ECG Signal Quality During Arrhythmia and Its Application to False Alarm Reduction

Development of Surrogate Spinal Cords for the Evaluation of Electrode Arrays Used in Intraspinal Implants

Noninvasive Biomagnetic Detection of Isolated Ischemic Bowel Segments

An Experimental Vestibular Neural Prosthesis: Design and Preliminary Results With Rhesus Monkeys Stimulated With Modulated Pulses

Feature-Preserving Smoothing of Diffusion Weighted Images Using Nonstationarity Adaptive Filtering

The Alpha Band of the Resting Electroencephalogram Under Pulsed and Continuous Radio Frequency Exposures

A Fully Constrained Optimization Method for Time-Resolved Multispectral Fluorescence Lifetime Imaging Microscopy Data Unmixing

Optimization of Mechanical Ventilator Settings for Pulmonary Disease States

Ultrasound-Guided Characterization of Interstitial Ablated Tissue Using RF Time Series: Feasibility Study

Motion of the Kidney Between Preoperative and Intraoperative Positioning

A Reconfigurable Digital Filterbank for Hearing-Aid Systems With a Variety of Sound Wave Decomposition Plans

Effects of Robotic Knee Exoskeleton on Human Energy Expenditure

Development of a Wireless Sensor for the Measurement of Chicken Blood Flow Using the Laser Doppler Blood Flow Meter Technique

The Use of a Bone-Anchored Device as a Hard-Wired Conduit for Transmitting EMG Signals From Implanted Muscle Electrodes

Fold-Preserving Electronic Cleansing Using a Reconstruction Model Integrating Material Fractions and Structural Responses

Denoising MRI Using Spectral Subtraction

Confidence-Based Rejection for Improved Pattern Recognition Myoelectric Control

Photon Efficiency Optimization in Time-Correlated Single Photon Counting Technique for Fluorescence Lifetime Imaging Systems

Novel Bayesian Vectorcardiographic Loop Alignment for Improved Monitoring of ECG and Fetal Movement

A Variational Surface Deformation and Subdivision-Based Modeling Framework for Noisy and Small -Furcated Tube-Like Structures

An Impulse Radio Ultrawideband System for Contactless Noninvasive Respiratory Monitoring

Flocking Multiple Microparticles With Automatically Controlled Optical Tweezers: Solutions and Experiments

Debye Parameter Extraction for Characterizing Interaction of Terahertz Radiation With Human Skin Tissue

Mechatronic Design of a Fully Integrated Camera for Mini-Invasive Surgery

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IEEE Transactions on Biomedical Engineering publication information

Table of contents

Surgical Tool Alignment Guidance by Drawing Two Cross-Sectional Laser-Beam Planes

A Ridge Ensemble Empirical Mode Decomposition Approach to Clutter Rejection for Ultrasound Color Flow Imaging

Consciousness and Depth of Anesthesia Assessment Based on Bayesian Analysis of EEG Signals

A Comprehensive 3-D Framework for Automatic Quantification of Late Gadolinium Enhanced Cardiac Magnetic Resonance Images

Classification of emotional States from electrocardiogram signals: a non-linear approach based on hurst

Performance assessment in brain-computer interface-based augmentative and alternative communication

Nanoparticle Network Acts As An Artificial Pancreas

A hybrid approach to the simultaneous eliminating of power-line interference and associated ringing artifacts in electrocardiograms

Editorial Board

Detecting fixation on a target using time-frequency distributions of a retinal birefringence scanning signal

Methods of measuring the iridocorneal angle in tomographic images of the anterior segment of the eye

Volumetric three-dimensional intravascular ultrasound visualization using shape-based nonlinear interpolation

Editorial Board

Table of Contents

IEEE Transactions on Medical Imaging publication information

Fast Joint Detection-Estimation of Evoked Brain Activity in Event-Related fMRI Using a Variational Approach

Dynamic 3-D Visualization of Vocal Tract Shaping During Speech

Detection and Analysis of Irregular Streaks in Dermoscopic Images of Skin Lesions

Quantitative Analysis of Cardiac Tissue Including Fibroblasts Using Three-Dimensional Confocal Microscopy and Image Reconstruction: Towards a Basis for Electrophysiological Modeling

Model-Driven Harmonic Parameterization of the Cortical Surface: HIP-HOP

Application of Radial Ray Based Segmentation to Cervical Lymph Nodes in CT Images

A Piecewise Monotone Subgradient Algorithm for Accurate -TV Based Registration of Physical Slices With Discontinuities in Microscopy

Registration of Coronary CTA and Monoplane X-Ray Angiography

Sparse Signal Recovery Methods for Multiplexing PET Detector Readout

A General Framework for Context-Specific Image Segmentation Using Reinforcement Learning

Distributed MLEM: An Iterative Tomographic Image Reconstruction Algorithm for Distributed Memory Architectures

2013 ieee nss/mic/rtsd

IEEE Transactions on Medical Imaging information for authors

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Neurovascular coupling: in vivo optical techniques for functional brain imaging

Detection of the valvular split within the second heart sound using the reassigned smoothed pseudo Wigner-Ville distribution

In vivo MRI-based simulation of fatigue process: a possible trigger for human carotid atherosclerotic plaque rupture

Bone formation in rabbit cancellous bone explant culture model is enhanced by mechanical load

Review of "orthopaedic biomechanics" edited by Beth A. Winkelstein

Review of ¿orthopaedic biomechanics¿ edited by Beth A. Winkelstein

Motor recovery monitoring using acceleration measurements in post acute stroke patients

Dependence of model-based RSA accuracy on higher and lower implant surface model quality

IEEE Transactions on Signal Processing publication information

Table of Contents

Time-of-Arrival Estimation Based on Information Theoretic Criteria

Wavelet Denoising Based on the MAP Estimation Using the BKF Prior With Application to Images and EEG Signals

Space-Time-Frequency (STF) MIMO Communication Systems With Blind Receiver Based on a Generalized PARATUCK2 Model