- Marios S. Pattichis (Fellow of the European Alliance of Medical and Biological Engineering and Science (EAMBES), Seni... moreMarios S. Pattichis (Fellow of the European Alliance of Medical and Biological Engineering and Science (EAMBES), Senior Member of IEEE) received the B.Sc. degree (Hons.) in computer sciences, the B.A. degree (Hons.) in mathematics, the M.S. degree in electrical engineering, and the Ph.D. degree in computer engineering from The University of Texas at Austin, Austin, in 1991, 1993, and 1998, respectively. He is currently a Professor with the Department of Electrical and Computer Engineering, University of New Mexico (UNM), Albuquerque. His current research interests include biomedical image and video analysis and communications, and explainable image representations.At UNM, he holds the Gardner Zemke Professorship in Teaching at ECE. He was a fellow of the Center for Collaborative Research and Community Engagement with the College of Education and Human Sciences for 2019-2020. He was a recipient of the 2016 Lawton-Ellis and the 2004 Distinguished Teaching Awards from the Department of Electrical and Computer Engineering, UNM. For his development of the digital logic design laboratories at UNM, he was recognized by Xilinx Corporation, in 2003 and by the UNM School of Engineering’s Harrison Faculty Excellent Award, in 2006. He was the General Chair of the 2008 IEEE Southwest Symposium on Image Analysis and Interpretation (SSIAI) and served as a General Co-Chair of the 2020 IEEE SSIAI. He served as a Senior Associate Editor for the IEEE Transactions on Image Processing, Senior Associate Editor for the IEEE Signal Processing Letters, Associate Editor for the IEEE Transactions on Image Processing, Associate Editor for the IEEE Transactions on Industrial Informatics, Guest Associate Editor for the IEEE Transactions on Information Technology in Biomedicine, and Pattern Recognition. He is currently a guest editor to a special issue on teaching and learning mathematics and computing in a multilingual context to be published by Teachers College Record, and a special issue on large-scale video analytics for clinical decision support, to be published by the IEEE Journal of Biomedical and Health Informatics.edit
The thickness of the intima-media complex (IMC) of the common carotid artery (CCA) wall is important in the evaluation of the risk for the development of atherosclerosis. This paper presents a fully automated algorithm for the... more
The thickness of the intima-media complex (IMC) of the common carotid artery (CCA) wall is important in the evaluation of the risk for the development of atherosclerosis. This paper presents a fully automated algorithm for the segmentation of the IMC. The segmentation of the IMC of the CCA wall is important for the evaluation of the intima media thickness (IMT) on B-mode ultrasound images. The presented algorithm is based on active contours and active contours without edges. It begins with image normalization, followed by speckle removal. The level set formulation of Chan and Vese using random initialization provides a segmentation of the CCA ultrasound (US) images into different distinct regions, one of which corresponds to the carotid wall region above the lumen whilst another corresponds to the carotid wall region below the lumen and includes the IMC. The results of the corresponding segmentation combined with anatomical information provide a very accurate outline of the lumen-in...
Research Interests: Computer Science, Algorithms, Artificial Intelligence, Computer Vision, Atherosclerosis, and 15 moreMedia, Medicine, Image segmentation, Humans, Automation, Edge Detection, Medical Engineering, Segmentation, Level Set, Active Contour, Engineering and Technology, Active Contours, Ground Truth, Automatic segmentation, and Image edge detection
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Research Interests: Computer Science, Algorithms, Image Analysis, Medicine, Humans, and 15 moreFemale, Male, Feature Extraction, Diagnostic Imaging, Aged, High Resolution, Adult, Cardiovascular Diseases, Asymptomatic, Carotid Artery, Internal Carotid Artery, Carotid Stenosis, Carotid Artery Stenosis, Cohort Studies, and Carotid Arteries
Image registration is a vital step in the processing of multispectral imagery. The accuracy to which imagery collected at multiple wavelengths can be aligned directly affects the resolution of the spectral end products. Automated... more
Image registration is a vital step in the processing of multispectral imagery. The accuracy to which imagery collected at multiple wavelengths can be aligned directly affects the resolution of the spectral end products. Automated registration of the multispectral imagery can often be unreliable, particularly between visible and infrared imagery, due to the significant differences in scene reflectance at different wavelengths. This is further complicated by the thermal features that exist at longer wavelengths. We develop new mathematical and computational models for robust image registration. In particular, we develop a frequency-domain model for the mutual-information surface around the optimal parameters and use it to develop a robust gradient ascent algorithm. For a robust performance, we require that the algorithm be initialized close to the optimal registration parameters. As a measure of how close we need to be, we propose the use of the correlation length and provide an efficient algorithm for estimating it. We measure the performance of the proposed algorithm over hundreds of random initializations to demonstrate its robustness on real data. We find that the algorithm should be expected to converge, as long as the registration parameters are initialized to be within the correlation-length distance from the optimum.
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Research Interests: Information Systems, Mathematics, Computer Science, Algorithms, Artificial Intelligence, and 15 moreComputer Vision, Biometry, Medicine, Dermatoglyphics, Humans, Information Storage and Retrieval, Image Modeling, Image Enhancement, Eigenvectors, Eigenvalues and Eigenvectors, Digital Image, Electrical And Electronic Engineering, Ordinary Differential Equation, Instantaneous frequency, and Image Texture
Research Interests: Engineering, Computer Science, Algorithms, Artificial Intelligence, Multiple sclerosis, and 15 moreMagnetic Resonance Imaging, Medicine, Brain, Humans, Ultrasonography, Female, Male, Aged, Middle Aged, Adult, Sex Factors, Age Factors, Area Under Curve, Carotid Arteries, and Medical and Health Sciences
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Through this study we are presenting the initial steps towards a real time motion analysis system to predict the stability of carotid bifurcation plaques. The analysis is performed on B-mode video loops. Loops are analyzed in order to... more
Through this study we are presenting the initial steps towards a real time motion analysis system to predict the stability of carotid bifurcation plaques. The analysis is performed on B-mode video loops. Loops are analyzed in order to follow systole and diastole sections of the cardiac cycle and trace the motion of plaques during these periods. We had created a system that applies Farnebacks optical flow estimation method in order to estimate the flow between consecutive frames or frames at a predefined interval. Over each pair of video frames we measure velocities, orientation and magnitude of movement. The goal is to identify if a plaque has movement spread to different angles or at nearby angles. This can help us identify discordant or concordant movement. In order to verify our system we had created a set of simulated videos that have structures moving in a similar way as done in a cardiac cycle and videos that move and appear as an atherosclerotic artery. Following these tests the system has been tested and results are presented on two carotid plaques videos classified visually as having concordant and discordant plaque movement.
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The prevalence of video driven applications, leveraging over the top video on demand services as well as live video streaming applications, dominate network traffic over today’s internet landscape. As such, they necessitate efficient... more
The prevalence of video driven applications, leveraging over the top video on demand services as well as live video streaming applications, dominate network traffic over today’s internet landscape. As such, they necessitate efficient video compression methods to accommodate the desired quality of service and hence user experience. In this study, we compare the performances of the emerging versatile video coding (VVC) standard, the recently released AV1 encoder (using SVTAV1 instance), the established high efficiency video coding (HEVC) standard via its x265 implementation, and the earlier VP9 codec. We used selected videos coming from three different datasets, namely UT LIVE (432p), and HEVC test sequences (480p, 720p, 1080p) that provide diversity in video content, video resolutions, and frame rates. The experimental setup involved fixed quality encoding using four different rate points, and more specifically, QP values of 27, 35, 46, 55 for AV1 and VP9 and QP values of 22, 27, 32, 37 for VVC and x265 codecs. For estimating bitrate gains, we used the BD-RATE algorithm using both PSNR and VMAF for objective video quality assessment (VQA). We found that VVC achieved the best video coding performance, significantly outperforming all other codecs. AV1 consistently outperformed x265, but with narrow margins in some video sequences, suggesting that a cautious selection between the two codecs needs to based on application-specific criteria. Within the group of considered codecs, VP9 required the highest bitrates. Ongoing work involves extending the examined video datasets pool to different resolutions (e.g., 240p, 1600p) while investigating the correlation between subjective and objective VQA scores.
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We present a framework for adaptive video encoding based on video content. The basic idea is to analyze the video to determine camera activity (tracking, stationary, or zooming) and then associate each activity with adaptive video quality... more
We present a framework for adaptive video encoding based on video content. The basic idea is to analyze the video to determine camera activity (tracking, stationary, or zooming) and then associate each activity with adaptive video quality constraints. We demonstrate our approach on the UT LIVE video quality assessment database that effective camera activity detection and classification is possible based on the motion vectors and the number of prediction units (PU) extracted using x265 HEVC encoding standard. In our results, by applying leave-one-out validation, we get an 79% correct classification rate using kNN binary classifier for the video segments.
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As understanding of a particular problem domain matures, its tools become more specialized, moving from general low-level tools to more specialized high-level tools. Early work in a field applies the same set of low-level aids to all... more
As understanding of a particular problem domain matures, its tools become more specialized, moving from general low-level tools to more specialized high-level tools. Early work in a field applies the same set of low-level aids to all problems. Gradually more specialized tools emerge as we come to better understand the problem and the tools that are best for it. Since the emergence of the first program editors in the early 1960s we have learned a lot about the editing process and about building editors. Recently several editors specialized for editing program sources, text, and data structures have been developed. To date, little work has been reported on specialized document editors for editing complex text. This paper describes a research effort into identifying the requirements for an interactive environment for editing complex documents and an initial implementation for the environment.
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The wider adoption of mobile Health (mHealth) video communication systems in standard clinical practice requires real-time control to provide for adequate levels of clinical video quality to support reliable diagnosis. The latter can only... more
The wider adoption of mobile Health (mHealth) video communication systems in standard clinical practice requires real-time control to provide for adequate levels of clinical video quality to support reliable diagnosis. The latter can only be achieved with real-time adaptation to time-varying wireless networks' state to guarantee clinically acceptable performance throughout the streaming session, while conforming to device capabilities for supporting real-time encoding.
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There is strong interest in developing high-performance hardware sorting systems which can sort a set of elements as quickly as possible. The fastest of the current FPGA systems are sorting networks, in which sets of 2-sorters operate in... more
There is strong interest in developing high-performance hardware sorting systems which can sort a set of elements as quickly as possible. The fastest of the current FPGA systems are sorting networks, in which sets of 2-sorters operate in parallel in each series stage of a multi-stage sorting process. A 2-sorter is a single-stage hardware block which sorts two values, so any list with more than 2 values must be sorted with a series network of 2-sorters. A primary contribution of this work is to provide a general methodology for the design of stable single-stage hardware sorters which sort more than 2 values simultaneously. This general methodology for N-sorter design, with N >2, is then adapted for use in modern FPGAs, where it is shown that single-stage 3-sorters up to 9-sorters have speedup ratios from 2.0 to 3.5 versus the comparable state-of-the-art 2-sorter networks. A design system modification is shown to produce even faster single-stage N-max and N-min filters. When used for max pooling 32-bit data in the fastest analyzed FPGA, a single 9-max filter will process 500 million 9-pixel groups per second (4K:3840x2160 at 500 frames/second). The single-stage 9-median filter using this design methodology, useful in image processing, is shown to have speedup ratios of 3.0 to 4.1 versus state-of-the-art FPGA network implementations, even though its resource usage is comparable to, often better than, the network implementations. Ten 8-bit 9-median filters operating in parallel in the fastest FPGA will process over 5.4 billion pixels/sec (4K at over 600 frames/second). INDEX TERMS Field programmable gate arrays, FPGA, image filtering, merging, sorting, sorting networks, max pooling, median filters.
In hardware such as FPGAs, Kenneth Batcher's Odd-Even Merge Sort and Bitonic Merge Sort are the state-of-the-art methodologies used to quickly sort a list of more than 16 input values. Both sorting networks feature merges of 2 sorted... more
In hardware such as FPGAs, Kenneth Batcher's Odd-Even Merge Sort and Bitonic Merge Sort are the state-of-the-art methodologies used to quickly sort a list of more than 16 input values. Both sorting networks feature merges of 2 sorted input lists into a single sorted output list. For both, a full sort of 64 and 512 input values requires 21 and 45 serial stages, respectively. Multiway merge sorting networks described here require significantly fewer serial stages. For example, 8-way merge networks fully sort 64 and 512 input values in 9 and 20 serial stages, less than half the number of the respective 2-way networks. When the multiway merge sorting networks utilize the single-stage N-sorters recently defined by the authors, they are considerably faster than Batcher's networks. In the AMD-Xilinx Ultrascale+ xcvu9p FPGA, the two 8-way merge networks have speedups of 1.85 and 1.74 versus the comparable 2-way networks. A fully pipelined 3-way merge network in this FPGA is capable of fully sorting 500 million lists of 729 unsorted 32-bit values in one second. In software, multiway merge methods are used to find the median of certain pixel rectangles in images, since the median can be determined in fewer stages than are required to fully sort the rectangle. However, the software still requires a series of many 2-sorter operations to find a median. These multiway merge median methods are dramatically sped up in hardware, where the authors' new single-stage N-sorters and N-filters operate in parallel in each stage of the merge process.