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作者： Trenholm, Stuart Dalhousie University

学位级别：doctor

Early experimental work suggested that the retina’smain role was to detect changes in brightness and contrast, namelyworking as a light detector, and that most of the complexcomputations in the visual system happened upstream in the *** reality, there is a growing wealth of literature indicating thatthe retina itself processes multiple channels of visual information(contrast, motion, orientation, etc.), making it much more complexthan it originally appeared. For instance, there now appear to beover 20 types of retinal ganglion cells. To this end, the work inthis thesis will focus on the identification and characterizationof a single type of retinal ganglion cell in the mouse retina. Inthe first section of my results, I will show that this cell type,identified as the only GFP+ ganglion cell in the transgenicHb9::eGFP retina, is a directionally selective ganglion cell(DSGC), that preferentially responds to objects moving upwardthrough the visual field. This cell has a pronounced morphologicalasymmetry that helps it to synergistically (along with asymmetricinhibition) generate directionally selective responses. In thesecond results section, I will describe a novel phenomenonexhibited by Hb9+ DSGCs: Thanks to gap junction mediated signals,Hb9+ cells are able to anticipate moving stimuli and correct forlags that are inherent in visual signals generated byphotoreceptors. In the third results section I will elucidate themechanisms for the gap junction mediated anticipatory signalsoutlined in the second results section. Together, these resultsprovide a significant advancement in our understanding of how theretina processes moving stimuli and provide a compelling example ofhow chemical and electrical synapses interact to allow forexquisite signal multiplexing

关键词： Retina Direction Selectivity motion coding Gap Junctions Electrophysiology 2-Photon Imaging

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A Study of motion coding Schemes for Learned Video Compression 35

A Study of Motion Coding Schemes for Learned Video Compressi...

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35th SBC/SBMicro/IEEE/ACM Symposium on Integrated Circuits and Systems Design (SBCCI)

作者： Chen, Peng-Yu Lin, Chih-Hsuan Peng, Wen-Hsiao Natl Yang Ming Chiao Tung Univ Dept Comp Sci Taipei Taiwan

ISBN: (数字)9781665481281

ISBN: (纸本)9781665481281

This paper presents a study of motion coding schemes for learned video compression. Most learned video compression systems explicitly signal optical flow maps to characterize motion between video frames for motion compensation. The flow maps, usually of the same size as the video frames, represent a considerable portion of the compressed bitstream. This work studies several schemes to make a non-linear prediction of the flow maps for efficient motion coding. These include signaling an incremental flow map between a coding frame and a motion-compensated frame derived from the flow map predictor. In forming the flow map predictor, we propose a learned motion extrapolation module and a motion forward warping scheme. They are further incorporated into two novel approaches, termed double warping and frame synthesis with motion forward warping, in creating an inter-frame predictor by combining the incremental flow and the flow map predictor. Extensive experiments are conducted to analyze the merits and faults of these variants, and demonstrate their superiority to predictive motion coding and intra motion coding.

关键词： Learned Video Compression motion coding

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Enhanced motion coding in MC-EZBC

Enhanced motion coding in MC-EZBC

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Conference on Visual Communications and Image Processing 2005

作者： Chen, JH Zhang, WJ Wang, YK Shanghai Jiao Tong Univ Inst Image Commun & Informat Proc Shanghai 201101 Peoples R China

ISBN: (纸本)0819459763

Since hierarchical variable size block matching and bidirectional motion compensation are used in the motion-compensated embedded zero block coding (MC-EZBC), the motion information consists of motion vector quadtree map and motion vectors. In the conventional motion coding scheme, the quadtree structure is coded directly, the motion vector modes are coded with Huffman codes, and the motion vector differences are coded by an mary arithmetic coder with 0-order models. In this paper we propose a new motion coding scheme which uses an extension of the CABAC algorithm and new context modeling for quadtree structure coding and mode coding. In addition, we use a new scalable motion coding method which scales the motion vector quadtrees according to the rate-distortion slope of the tree nodes. Experimental results show that the new coding scheme increases the efficiency of the motion coding by more than 25%. The performance of the system is improved accordingly, especially in low bit rates. Moreover, with the scalable motion coding, the subjective and objective coding performance is further enhanced in low bit rate scenarios.

关键词： motion coding context modeling arithmetic coding CABAC scalable MC-EZBC

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Tools for Video coding Beyond HEVC: Flexible Partitioning, motion Vector coding, Luma Adaptive Quantization, and Improved Deblocking

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2020年第5期30卷 1361-1373页

作者： Misra, Kiran Segall, Andrew Bossen, Frank Sharp Labs Amer Inc Vancouver WA 98683 USA Sharp Elect Canada Ltd Mississauga ON L4Z 1W9 Canada

This paper provides a description and analysis of technology included in two contributions to the Call for Proposals for Video Compression with Capability beyond HEVC. This Call for Proposals was issued jointly by the Moving Picture Experts Group (MPEG) and the Video coding Experts Group (VCEG). The contribution emphasized a flexible and rectangular partitioning structure, which was combined with both new and existing coding tools. New coding tools included methods for improved motion vector coding, quantization signaling, and deblocking;while existing tools were largely methods studied in the Joint Exploration Model software. Results show the efficacy of the approach. Using the sequences and test conditions defined in the Call for Proposals, the described approach provided an average bitrate reduction, relative to an HEVC anchor, of 41.2% and 35.7% for 4K and HD test sequences, respectively. Moreover, the method achieved a compression performance of 34.3% and 32.2% for high dynamic range content using the perceptual quantizer (PQ) and Hybrid-Log Gamma transfer functions, respectively.

关键词： Encoding Proposals Dynamic range Tools Quantization (signal) High efficiency video coding Video coding separate partitioning trees motion coding deblocking

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motion differential set partition coding for image sequence and video compression

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JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION 2012年第4期23卷 634-641页

作者： Hu, Yang Pearlman, William A. Rensselaer Polytech Inst Dept Elect Comp & Syst Engn Troy NY 12180 USA

Efficient image sequence coding exploits both intra- and inter-frame correlations. Set partition coding (SPC) is efficient in intra-frame de-correlation for still images. Based on SPC, a novel image sequence coding system, called motion differential SPC (M-D-SPC), is presented in this paper. It removes inter-frame redundancy by re-using the significance map of a previously SPC coded frame. Every frame is encoded and decoded separate from other frames. Furthermore, there is no reconstruction of encoded frames in the encoder, as is done with interframe prediction methods. The M-D-SPC exhibits an auxiliary key frame coding framework, which achieves higher coding efficiency compared to the all-intra-coding schemes and meanwhile maintains the beneficial features of SPC all-intra-coding, such as computational simplicity, rate scalability, error non-propagation, and random frame access. SPIHT-based simulations on hyperspectral images, 3D/4D medical images, and video show greater compression efficiency than the standard intraframe coding method of motion JPEG2000. (c) 2012 Elsevier Inc. All rights reserved.

关键词： Video coding Image sequence coding motion coding Set partition coding Significance map SPIHT Random access Lossless coding

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Crowd Behavior Analysis via Curl and Divergence of motion Trajectories

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INTERNATIONAL JOURNAL OF COMPUTER VISION 2017年第3期123卷 499-519页

作者： Wu, Shuang Yang, Hua Zheng, Shibao Su, Hang Fan, Yawen Yang, Ming-Hsuan Shanghai Jiao Tong Univ Inst Image Proc & Network Engn Dept Elect Engn Shanghai Peoples R China Tsinghua Univ Dept Comp Sci & Technol Beijing Peoples R China Nanjing Univ Posts & Telecommun Coll Telecommun & Informat Engn Nanjing Jiangsu Peoples R China Univ Calif Merced Sch Engn Merced CA 95343 USA

In the field of crowd behavior analysis, existing methods mainly focus on using local representations inspired by models found in other disciplines (e.g., fluid dynamics and social dynamics) to describe motion patterns. However, less attention is paid to exploiting motion structures (e.g., visual information contained in trajectories) for behavior analysis. In this paper, we consider both local characteristics and global structures of a motion vector field, and propose the Curl and Divergence of motion Trajectories (CDT) descriptors to describe collective motion patterns. To this end, a trajectory-based motion coding algorithm is designed to extract the CDT descriptors. For each motion vector field we construct its conjugate field, in which each vector is perpendicular to the counterpart in the original vector field. The trajectories in the motion and corresponding conjugate fields indicate the tangential and radial motion structures, respectively. By integrating curl (and divergence, respectively) along the tangential paths (and the radial paths, respectively), the CDT descriptors are extracted. We show that the proposed motion descriptors are scale- and rotation-invariant for effective crowd behavior analysis. For concreteness, we apply the CDT descriptors to identify five typical crowd behaviors (lane, clockwise arch, counterclockwise arch, bottleneck and fountainhead) with a pipeline including motion decomposition. Extensive experimental results on two benchmark datasets demonstrate the effectiveness of the CDT descriptors for describing and classifying crowd behaviors.

关键词： Crowd behavior analysis Curl Divergence motion trajectories motion coding Path integration

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Object shape deformation with spherical harmonic interpolation

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ELECTRONICS LETTERS 1998年第17期34卷 1657-1658页

作者： Erturk, S Dennis, TJ Univ Essex Dept Elect Syst Engn Colchester CO4 3SQ Essex England

The authors introduce a method to reconstruct shape deformations of objects using linear interpolation of spherical harmonic (SH) representation parameters. It is shown that uniform shape deformation results in fairly linear changes in SH parameters. Therefore, shape changes can be reconstructed once the characteristics of the deformation are obtained in the SH domain.

关键词： spherical harmonic interpolation image segmentation shape deformation reconstruction Pattern recognition Interpolation and function approximation (numerical analysis) image representation Graphics techniques Codes linear interpolation animation image coding Optical information, image and video signal processing object recognition Computer vision and image processing techniques image reconstruction object shape deformation motion estimation interpolation computer animation uniform shape deformation motion coding

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USE OF RECURSIVE BINARY NESTING FOR coding MOVING IMAGE SEQUENCES

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ELECTRONICS LETTERS 1989年第5期25卷 362-363页

作者： CORDELL, PJ CLARKE, RJ Dept. of Electr. & Electron. Eng. Heriot-Watt Univ. Edinburgh UK

Recursive binary nesting (RBN) is a quadtree-based interpolation technique originally developed for still picture coding, which the authors have modified efficiently to code moving sequences. When the basic technique is used for motion coding, visually disturbing effects occur. The causes of these are identified and the algorithm modified to remove them.

关键词： coding moving image sequences computerised picture processing data compression encoding motion coding quadtree-based interpolation technique recursive binary nesting video signals videotelephony visually disturbing effects removal picture encoding

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Parallel H.263 video encoder in normal coding mode

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ELECTRONICS LETTERS 1998年第22期34卷 2109-2110页

作者： Cosmas, JP Paker, Y Pearmain, AJ Univ London Queen Mary & Westfield Coll Dept Elect Engn London E1 4NS England

A parallel H.263 video encoder, which utilises spatial pal allelism, has been modelled using a multi-threaded program. Spatial parallelism is a technique where an image is subdivided into equal parts las far as physically possible) and each part is processed by a separate processor by computing motion and texture coding with all processors each acting on a different part of the image. This method leads to a performance increase, which is roughly in proportion to the number of parallel processors used.

关键词： motion estimation multi-threaded program parallel processors spatial parallelism texture coding multi-threading Image and video coding motion coding equal parts Video signal processing parallel H.263 video encoder image texture video coding Multiprocessing systems normal coding mode parallel processing

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Supporting visual queries on medium-sized node–link diagrams

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Information Visualization 1997年第1期4卷 49-58页

作者： Ware, Colin Bobrow, Robert Data Visualization Research Laboratory Center for Coastal and Ocean Mapping University of New Hampshire Durham NH United States BBN Technologies Inc. Cambridge MA United States

For reasons of clarity, a typical node–link diagram statically displayed on paper or a computer screen contains fewer than 30 nodes. However, many problems would benefit if far more complex information could be diagrammed. Following Munzner et al., we suggest that with interactive diagrams this may be possible. We describe an interactive technique whereby a subset of a larger network diagram is highlighted by being set into oscillatory motion when a node is selected with a mouse. The subset is determined by a breadth first search of the underlying graph starting from the selected node. This technique is designed to support visual queries on moderately large node-link diagrams containing up to a few thousand nodes. An experimental evaluation was carried out with networks having 32, 100, 320, 1000, and 3200 nodes respectively, and with four highlighting techniques: static highlighting, motion highlighting, static+motion highlighting, and none. The results show that the interactive highlighting methods support rapid visual queries of nodes in close topological proximity to one another, even for the largest diagrams tested. Without highlighting, error rates were high even for the smallest network that was evaluated. motion highlighting and static highlighting were equally effective. A second experiment was carried out to evaluate methods for showing two subsets of a larger network simultaneously in such a way that both are clearly distinct. The specific task was to determine if the two subsets had nodes in common. The results showed that this task could be performed rapidly and with few errors if one subset was highlighted using motion and the other was highlighted using a static technique. We discuss the implications for information visualization. © 2005, SAGE Publications. All rights reserved.

关键词： Graph visualization interactive animation motion coding

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