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https://www.readbyqxmd.com/read/28098797/nonlinear-fusion-of-multispectral-citrus-fruit-image-data-with-information-contents
#1
Peilin Li, Sang-Heon Lee, Hung-Yao Hsu, Jae-Sam Park
The main issue of vison-based automatic harvesting manipulators is the difficulty in the correct fruit identification in the images under natural lighting conditions. Mostly, the solution has been based on a linear combination of color components in the multispectral images. However, the results have not reached a satisfactory level. To overcome this issue, this paper proposes a robust nonlinear fusion method to augment the original color image with the synchronized near infrared image. The two images are fused with Daubechies wavelet transform (DWT) in a multiscale decomposition approach...
January 13, 2017: Sensors
https://www.readbyqxmd.com/read/28097047/quantifying-the-on-and-off-contributions-to-the-flash-erg-with-the-discrete-wavelet-transform
#2
Mathieu Gauvin, Maja Sustar, John M Little, Jelka Brecelj, Jean-Marc Lina, Pierre Lachapelle
PURPOSE: Discrete wavelet transform (DWT) analyses suggest that the 20- and 40-Hz components of the short-flash photopic electroretinogram (ERG) are closely related to the ON and OFF pathways, respectively. With the DWT, we examined how the ERG ON and OFF components are modulated by the stimulus intensity and/or duration. METHODS: Discrete wavelet transform descriptors (20, 40 Hz and 40:20-Hz ratio) were extracted from ERGs evoked to 25 combinations of flash durations (150-5 ms) and strengths (0...
January 2017: Translational Vision Science & Technology
https://www.readbyqxmd.com/read/28092536/improved-denoising-via-poisson-mixture-modeling-of-image-sensor-noise
#3
Jiachao Zhang, Keigo Hirakawa
This paper describes a study aimed at comparing the real image sensor noise distribution to the models of noise often assumed in image denoising designs. Quantile analysis in pixel, wavelet transform, and variance stabilization domains reveal that the tails of Poisson, signal-dependent Gaussian, and Poisson-Gaussian models are too short to capture real sensor noise behavior. A new Poisson mixture noise model is proposed to correct the mismatch of tail behavior. Based on the fact that noise model mismatch results in image denoising that undersmoothes real sensor data, we propose a mixture of Poisson denoising method to remove the denoising artifacts without affecting image details such as edge and textures...
January 10, 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
https://www.readbyqxmd.com/read/28092514/a-multivariate-approach-for-patient-specific-eeg-seizure-detection-using-empirical-wavelet-transform
#4
Abhijit Bhattacharyya, Ram Bilas Pachori
OBJECTIVE: This paper investigates the multivariate oscillatory nature of electroencephalogram (EEG) signals in adaptive frequency scales for epileptic seizure detection. METHODS: The empirical wavelet transform (EWT) has been explored for the multivariate signals in order to determine the joint instantaneous amplitudes and frequencies in signal adaptive frequency scales. The proposed multivariate extension of EWT has been studied on multivariate multi-component synthetic signal, as well as on multivariate EEG signals of CHB-MIT scalp EEG database...
January 9, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28091395/a-novel-onset-detection-technique-for-brain-computer-interfaces-using-sound-production-related-cognitive-tasks-in-simulated-online-system
#5
YoungJae Song, Francisco Sepulveda
OBJECTIVE: Self-paced EEG-based BCIs (SP-BCIs) have traditionally been avoided due to two sources of uncertainty: (1) precisely when an intentional command is sent by the brain, i.e., the command onset detection problem, and (2) how different the intentional command is when compared to non-specific (or idle) states. Performance evaluation is also a problem and there are no suitable standard metrics available. In this paper we attempted to tackle these issues. APPROACH: Self-paced covert sound-production cognitive tasks (i...
February 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28086909/fast-detection-and-data-compensation-for-electrodes-disconnection-in-long-term-monitoring-of-dynamic-brain-electrical-impedance-tomography
#6
Ge Zhang, Meng Dai, Lin Yang, Weichen Li, Haoting Li, Canhua Xu, Xuetao Shi, Xiuzhen Dong, Feng Fu
BACKGROUND: Electrode disconnection is a common occurrence during long-term monitoring of brain electrical impedance tomography (EIT) in clinical settings. The data acquisition system suffers remarkable data loss which results in image reconstruction failure. The aim of this study was to: (1) detect disconnected electrodes and (2) account for invalid data. METHODS: Weighted correlation coefficient for each electrode was calculated based on the measurement differences between well-connected and disconnected electrodes...
January 7, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28079524/spatial-heterogeneity-in-the-time-and-frequency-properties-of-skin-perfusion
#7
Michele Sorelli, Zlatka Stoyneva, Irina Mizeva, Leonardo Bocchi
Pathological alterations of the microcirculatory system can be identified by measuring the temporal and spectral properties of Laser Doppler Flowmetry (LDF) signals acquired on the skin, and their changes following physiological stimulation. A wide range of stimulation protocols and measurement locations are observed in literature. Researchers often use non-invasive stimulation techniques, such as post-occlusive hyperaemia, cold tests, and local heating. As concerns the stimulation/recording sites, the forearm, fingers, and toes are typically selected to conduct microcirculation studies...
January 12, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28070749/an-automated-microemboli-detection-and-classification-system-using-backscatter-rf-signals-and-differential-evolution
#8
Karim Ferroudji, Nabil Benoudjit, Ayache Bouakaz
Embolic phenomena, whether air or particulate emboli, can induce immediate damages like heart attack or ischemic stroke. Embolus composition (gaseous or particulate matter) is vital in predicting clinically significant complications. Embolus detection using Doppler methods have shown their limits to differentiate solid and gaseous embolus. Radio-frequency (RF) ultrasound signals backscattered by the emboli contain additional information on the embolus in comparison to the traditionally used Doppler signals...
January 9, 2017: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28066844/tight-graph-framelets-for-sparse-diffusion-mri-q-space-representation
#9
Pew-Thian Yap, Bin Dong, Yong Zhang, Dinggang Shen
In diffusion MRI, the outcome of estimation problems can often be improved by taking into account the correlation of diffusion-weighted images scanned with neighboring wavevectors in q-space. For this purpose, we propose in this paper to employ tight wavelet frames constructed on non-flat domains for multi-scale sparse representation of diffusion signals. This representation is well suited for signals sampled regularly or irregularly, such as on a grid or on multiple shells, in q-space. Using spectral graph theory, the frames are constructed based on quasi-affine systems (i...
October 2016: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
https://www.readbyqxmd.com/read/28063666/development-of-a-clinical-applicable-graphical-user-interface-to-automatically-detect-exercise-oscillatory-ventilation-the-vodex-tool
#10
Justien Cornelis, Tim Denis, Paul Beckers, Christiaan Vrints, Dirk Vissers, Maggy Goossens
BACKGROUND: Cardiopulmonary exercise testing (CPET) gained importance in the prognostic assessment of especially patients with heart failure (HF). A meaningful prognostic parameter for early mortality in HF is exercise oscillatory ventilation (EOV). This abnormal respiratory pattern is recognized by hypo- and hyperventilation during CPET. Up until now, assessment of EOV is mainly done upon visual agreement or manual calculation. The purpose of this research was to automate the interpretation of EOV so this prognostic parameter could be readily investigated during CPET...
December 29, 2016: International Journal of Cardiology
https://www.readbyqxmd.com/read/28059398/subtractive-two-frame-three-beam-phase-stepping-interferometry-for-testing-surface-shape-of-quasi-parallel-plates
#11
Zofia Sunderland, Krzysztof Patorski, Maciej Trusiak
We present an effective method of testing the surface shape of quasi-parallel plates which requires only two phase-shifted three-beam interferograms. We derive a general formula for difference of two three-beam interferograms as a function of the phase shift value. The phase shift does not have to be precisely determined and uniform in the image domain. We show and compare results of extracting the fringe set and corresponding phase distribution related to the plate front surface shape using the two dimensional continuous wavelet transform, Hilbert-Huang transform and Fourier transform methods...
December 26, 2016: Optics Express
https://www.readbyqxmd.com/read/28059337/wavelet-phase-extracting-demodulation-algorithm-based-on-scale-factor-for-optical-fiber-fabry-perot-sensing
#12
Baolin Zhang, Xinglin Tong, Pan Hu, Qian Guo, Zhiyuan Zheng, Chaoran Zhou
Optical fiber Fabry-Perot (F-P) sensors have been used in various on-line monitoring of physical parameters such as acoustics, temperature and pressure. In this paper, a wavelet phase extracting demodulation algorithm for optical fiber F-P sensing is first proposed. In application of this demodulation algorithm, search range of scale factor is determined by estimated cavity length which is obtained by fast Fourier transform (FFT) algorithm. Phase information of each point on the optical interference spectrum can be directly extracted through the continuous complex wavelet transform without de-noising...
December 26, 2016: Optics Express
https://www.readbyqxmd.com/read/28054947/hyperspectral-imagery-super-resolution-by-adaptive-pocs-and-blur-metric
#13
Shaoxing Hu, Shuyu Zhang, Aiwu Zhang, Shatuo Chai
The spatial resolution of a hyperspectral image is often coarse as the limitations on the imaging hardware. A novel super-resolution reconstruction algorithm for hyperspectral imagery (HSI) via adaptive projection onto convex sets and image blur metric (APOCS-BM) is proposed in this paper to solve these problems. Firstly, a no-reference image blur metric assessment method based on Gabor wavelet transform is utilized to obtain the blur metric of the low-resolution (LR) image. Then, the bound used in the APOCS is automatically calculated via LR image blur metric...
January 3, 2017: Sensors
https://www.readbyqxmd.com/read/28052436/quantification-of-1-h-mrs-signals-based-on-sparse-metabolite-profiles-in-the-time-frequency-domain
#14
Mohammad Ali Parto Dezfouli, Mohsen Parto Dezfouli, Alireza Ahmadian, Alejandro F Frangi, Melika Esmaeili Rad, Hamidreza Saligheh Rad
MRS is an analytical approach used for both quantitative and qualitative analysis of human body metabolites. The accurate and robust quantification capability of proton MRS ((1) H-MRS) enables the accurate estimation of living tissue metabolite concentrations. However, such methods can be efficiently employed for quantification of metabolite concentrations only if the overlapping nature of metabolites, existing static field inhomogeneity and low signal-to-noise ratio (SNR) are taken into consideration. Representation of (1) H-MRS signals in the time-frequency domain enables us to handle the baseline and noise better...
January 4, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28048555/su-c-207b-01-a-novel-graphics-processing-units-gpu-implementation-of-discrete-wavelet-transformation
#15
A Liu, M Chen, S Jiang, W Lu
PURPOSE: To design and implement a GPU-based discrete wavelet transformation (DWT) to be used in medical image reconstruction, image processing, and data compression. DWTs are widely used in medical physics, but the computation of DWTs is time consuming for large volumetric data. An efficient parallel implementation of DWTs is essential for many time sensitive applications, such as 4DCT. METHODS: We choose Daubechies wavelet transformations as a benchmark, implementing both DWT and inverse DWT (IDWT)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048093/su-f-j-27-segmentation-of-prostate-cbct-images-with-implanted-calypso-transponders-using-double-haar-wavelet-transform
#16
Y Liu, Z Saleh, Y Song, C Obcemea, M Chan, X Li, L Happersett, C Shi, X Qian, X Tang
PURPOSE: Segmentation of prostate CBCT images is an essential step towards real-time adaptive radiotherapy. It is challenging For Calypso patients, as more artifacts are generated by the beacon transponders. We herein propose a novel wavelet-based segmentation algorithm for rectum, bladder, and prostate of CBCT images with implanted Calypso transponders. METHODS: Five hypofractionated prostate patients with daily CBCT were studied. Each patient had 3 Calypso transponder beacons implanted, and the patients were setup and treated with Calypso tracking system...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28035635/ecg-signal-denoising-via-empirical-wavelet-transform
#17
Omkar Singh, Ramesh Kumar Sunkaria
This paper presents new methods for baseline wander correction and powerline interference reduction in electrocardiogram (ECG) signals using empirical wavelet transform (EWT). During data acquisition of ECG signal, various noise sources such as powerline interference, baseline wander and muscle artifacts contaminate the information bearing ECG signal. For better analysis and interpretation, the ECG signal must be free of noise. In the present work, a new approach is used to filter baseline wander and power line interference from the ECG signal...
December 29, 2016: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28013026/nonsubsampled-rotated-complex-wavelet-transform-nsrcxwt-for-medical-image-fusion-related-to-clinical-aspects-in-neurocysticercosis
#18
Satishkumar S Chavan, Abhishek Mahajan, Sanjay N Talbar, Subhash Desai, Meenakshi Thakur, Anil D'cruz
Neurocysticercosis (NCC) is a parasite infection caused by the tapeworm Taenia solium in its larvae stage which affects the central nervous system of the human body (a definite host). It results in the formation of multiple lesions in the brain at different locations during its various stages. During diagnosis of such symptomatic patients, these lesions can be better visualized using a feature based fusion of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). This paper presents a novel approach to Multimodality Medical Image Fusion (MMIF) used for the analysis of the lesions for the diagnostic purpose and post treatment review of NCC...
December 18, 2016: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/28006015/skipping-selected-steps-of-dwt-computation-in-lossless-jpeg-2000-for-improved-bitrates
#19
Roman Starosolski
In order to improve bitrates of lossless JPEG 2000, we propose to modify the discrete wavelet transform (DWT) by skipping selected steps of its computation. We employ a heuristic to construct the skipped steps DWT (SS-DWT) in an image-adaptive way and define fixed SS-DWT variants. For a large and diverse set of images, we find that SS-DWT significantly improves bitrates of non-photographic images. From a practical standpoint, the most interesting results are obtained by applying entropy estimation of coding effects for selecting among the fixed SS-DWT variants...
2016: PloS One
https://www.readbyqxmd.com/read/28000207/wavelet-analysis-of-resultant-velocity-belonging-to-genuine-and-forged-signatures
#20
Sharifah Mumtazah Syed Ahmad, Ling Yim Loo, Wan Azizun Wan Adnan, Rina Md Anwar
This study presents a wavelet analysis of resultant velocity features belonging to genuine and forged groups of signature sample. Signatures of individuals were initially classified based on visual human perceptions of their relative sizes, complexities, and legibilities of the genuine counterparts. Then, the resultant velocity was extracted and modeled through wavelet analysis from each sample. The wavelet signal was decomposed into several layers based on maximum overlap discrete wavelet transform (MODWT)...
December 21, 2016: Journal of Forensic Sciences
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