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IEEE TRANSACTIONS ON IMAGE PROCESSING 2001年第10期10卷 1397-1410页

作者： Wang, Z Bovik, AC Univ Texas Dept Elect & Comp Engn Lab Image & Video Engn Austin TX 78712 USA

The human visual system (HVS) is highly space-variant in sampling, coding, processing, and understanding. The spatial resolution of the HVS is highest around the point of fixation (foveation point) and decreases rapidly with increasing eccentricity. By taking advantage of this fact, it is possible to remove considerable high-frequency information redundancy from the peripheral regions and still reconstruct a perceptually good quality image. Great success has been obtained recently by a class of embedded wavelet image coding algorithms, such as the embedded zerotree wavelet (EZW) and the set partitioning in hierarchical trees (SPIHT) algorithms. Embedded wavelet coding not only provides very good compression performance, but also has the property that the bitstream can be truncated at any point and still be decoded to recreate a reasonably good quality image. In this paper, we propose an embedded foveation image coding (EFIC) algorithm, which orders the encoded bitstream to optimize foveated visual quality at arbitrary bit-rates. A foveation-based image quality metric, namely, foveated wavelet image quality index (FWQI), plays an important role in the EFIC system. We also developed a modified SPIHT algorithm to improve the coding efficiency. Experiments show that EFIC integrates foveation filtering with foveated image coding and demonstrates very good coding performance and scalability in terms of foveated image quality measurement.

关键词： embedded coding foveated image coding foveation foveation filtering human visual system (HVS) image coding image quality measurement progressive transmission scalable coding wavelet

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Accessing video contents through key objects over IP

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MULTIMEDIA TOOLS AND APPLICATIONS 2003年第1期21卷 75-96页

作者： Fan, JP Zhu, XQ Najarian, K Wu, LD Univ N Carolina Dept Comp Sci Charlotte NC 28223 USA Purdue Univ Dept Comp Sci W Lafayette IN 47907 USA Univ N Carolina Dept Comp Sci Charlotte NC 28223 USA Fudan Univ Dept Comp Sci Shanghai 200433 Peoples R China

In order to support content-based video database access over the Internet Protocol (IP), achieving the following objectives are important: (i) video query by a representative object (key object) or some statistical characterization of the target contents, (ii) bandwidth-efficient browsing over IP, and (iii) scalable and user-centric video transmission over a heterogeneous and variable-bandwidth network. We present a video object extraction and scalable coding system designed to meet the above objectives. In our system, key objects of meaning to video database users are generated via a human-computer-interaction procedure, and are tracked across frames. Given a key object, an algorithm classifies a subset of its VOPs as key VOPs. This subset forms the basis of a highly bandwidth-efficient base layer for supporting activities such as browsing and refining queries. Over the base layer, a number of enhancement layers can be defined to progressively increase the spatial and temporal resolutions of retrieved video. It is expected that heterogeneous users can subscribe to different numbers of the enhancement layers according to their own conditions, such as access authorization, available connection bandwidth, and quality preference.

关键词： semantic object extraction key object key VOP scalable coding

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Multiple description coding of animated meshes

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2010年第10期25卷 729-744页

作者： Bici, M. Oguz Akar, Gozde B. Middle E Tech Univ Dept Elect & Elect Engn Ankara Turkey

In this paper, we propose three novel multiple description coding (MDC) methods for reliable transmission of compressed animated meshes represented by series of 3D static meshes with same connectivity. The proposed methods trade off reconstruction quality for error resilience to provide the best expected reconstruction of 3D mesh sequence at the decoder side. The methods are based on layer duplication and partitioning of the set of vertices of a scalable coded animated mesh by either spatial or temporal subsampling. Each partitioned set is encoded separately to generate independently decodable bit-streams or so-called descriptions. In addition, the proposed MDC methods can achieve varying redundancy allocations by including a number of encoded spatial or temporal layers from the other description. The algorithms are evaluated with redundancy-rate-distortion (RRD) curves and per-frame reconstruction analysis. RRD performances show that vertex partitioning-based MDC performs better at low redundancies for especially spatially dense models. Temporal subsampling-based MDC performs better at moderate redundancies as well as low redundancies for spatially coarse models. Layer duplication-based MDC can achieve the lowest redundancies with flexible redundancy allocation capability and can be designed to achieve the smallest variance of reconstruction quality between consecutive frames. (C) 2010 Elsevier B.V. All rights reserved.

关键词： Multiple description coding Animated meshes 3D dynamic meshes Time consistent mesh sequence Subsampling scalable coding

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Content-based network resource allocation for real time remote laboratory applications

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SIGNAL IMAGE AND VIDEO PROCESSING 2010年第2期4卷 263-272页

作者： Mittal, Ankush Pande, Amit Kumar, Praveen Iowa State Univ Dept Elect & Comp Engn Ames IA 50011 USA Indian Inst Technol Dept Elect & Comp Engn Roorkee 247667 Uttar Pradesh India

This paper presents a practical solution to make remote laboratories a realizable dream. A remote laboratory is an online laboratory where students can get first-hand experience of engineering labs via Internet. Video transmission can provide hands on experience to the user but the transmission channel or networks typically have variable and low bandwidth that poses a tough constraint for such implementation. This work presents a practical solution to such problems by adaptively transmitting the best available quality of laboratory videos to the user depending on network bandwidth. The concept behind our work is that not all objects or frames of the video have equal importance, and thus bandwidth reduction can be accomplished by intelligently transmitting important parts at relatively higher resolution. A localized Time adaptive mean of Gaussian (L-TAMOG) approach is used to search for moving objects which are then allocated network resources dynamically according to the varying network bandwidth variations. Adaptive motion compensated wavelet-based encoding is used to achieve scalability and high compression. The proposed system tracks the network bandwidth and delivers optimally the most important contents of video to the student. Experimental results over several remote laboratory sequences show the efficiency of the proposed framework.

关键词： Multimedia systems L-TAMOG-based image segmentation Video transmission Interactive lab scalable coding Adaptive network resource allocation

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Coarse scale cost-utility approach for efficient unequal loss protection

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2002年第8期17卷 587-596页

作者： Chen, YS Wang, GP Dong, SH Peking Univ HCI & Multimedia Lab Dept Comp Sci Beijing 100871 Peoples R China

The framework of unequal loss protection (ULP) is an attractive method for the protection of the embedded image or video data source generated by a scalable coding scheme in the environment of packet switched networks. In this paper, an efficient preprocessing algorithm is presented based on the idea of the coarse scale cost-utility (CSCU) working curve. The experimental results show that the CSCU method significantly improves the efficiency of the ULP assignment framework with substantial memory and computation savings. We believe that the idea of coarse scale operation can also be successfully used in many other applications. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： scalable coding unequal loss protection forward error correcting multiple description coding

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Multiview coding and error correction coding for 3D video over noisy channels

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2015年 30卷 107-120页

作者： Vosoughi, Arash Testoni, Vanessa Cosman, Pamela C. Milstein, Laurence B. Univ Calif San Diego Dept Elect & Comp Engn La Jolla CA 92093 USA

We consider the joint source-channel coding problem of stereo video transmitted over AWGN and flat Rayleigh fading channels. Multiview coding (MVC) is used to encode the source, as well as a type of spatial scalable MVC. Our goal is to minimize the total number of bits, which is the sum of the number of source bits and the number of forward error correction bits, under the constraints that the quality of the left and right views must each be greater than predetermined PSNR thresholds at the receiver. We first consider symmetric coding, for which the quality thresholds are equal. Following binocular suppression theory, we also consider asymmetric coding, for which the quality thresholds are unequal. The optimization problem is solved using both equal error protection (EEP) and a proposed unequal error protection (UEP) scheme. An estimate of the expected end-to-end distortion of the two views is formulated for a packetized MVC bitstream over a noisy channel. The UEP algorithm uses these estimates for packet rate allocation. Results for various scenarios, including non-scalable/scalable MVC, symmetric/asymmetric coding, and UEP/EEP, are provided for both AWGN and flat Rayleigh fading channels. The UEP bit savings compared to EEP are given, and the performances of different scenarios are compared for a set of stereo video sequences. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Joint source-channel coding Multiview video coding Unequal error protection scalable coding Asymmetric coding

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Delay-constrained transmission of fine scalable coded content over P2P networks

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2005年第1期20卷 21-37页

作者： Su, X Shang, Y Wang, T Mai, YQ San Jose State Univ Dept Commun Engn San Jose CA 95192 USA Univ Missouri Dept Comp Sci Columbia MO 65211 USA Synopsys Inc Mountain View CA 94043 USA

Images or videos are generally coded before transmission, and they can be either non-scalable coded or scalable coded, which can be further classified into fine-scalable coded and coarse-scalable coded. In this paper, we focus on delivery of fine-scalable coded content. The objective of our work is to design algorithms to optimize the quality of fine-scalable coded images or videos on peer-to-peer networks when a requesting peer is delay-sensitive and has to display content within a certain delay bound. Fine-scalable coding has two properties: (1) it embeds lower bit-rate bitstreams into higher bit-rate bitstreams;and (2) its coding quality increases with every additional bit in the coded bitstream. These imply that for a given requesting peer, there may exist a dynamic set of supplying peers that have the same content coded in different bit-rates, have different outgoing bandwidth and may finish transmission at different times. In this paper, we first illustrate the importance of peer assignment problem using an example. Then we formally define and formulate the problem as two integer programming problems, from which we derive an optimal peer assignment solution. Finally, we carry out extensive experiments to verify the excellent performance of the proposed peer assignment algorithms by comparing with other heuristic schemes. (C) 2004 Elsevier B.V. All rights reserved.

关键词： image transmission scalable coding peer to peer networks, peer assignment

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Robust Video Region-of-Interest coding Based on Leaky Prediction

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2009年第9期19卷 1389-1394页

作者： Chen, Qian Yang, Xiaokang Song, Li Zhang, Wenjun Shanghai Jiao Tong Univ Inst Image Commun & Informat Proc Shanghai 200240 Peoples R China

A video region-of-interest (ROI) scalable coding scheme can ensure the priority of ROI. Error protection schemes can be used to guarantee the correct receipt of the ROI stream when transporting ROI scalable video over an error-prone network. However, we find that the correct receipt of ROI bitstreams cannot ensure the correct decoding of ROI due to the unique issue of the cross error propagation between ROI and background in ROI scalable coding. In this letter, we propose an ROI scalable coding framework based on leaky prediction (LP) for robustly transporting video over an error-prone network. Although several LP approaches have been proposed to improve layered coding, they cannot be applied to ROI scalable coding straightforwardly due to the cross error propagation issue. We deploy a leaky factor to weigh the two predictions: one from the constrained motion estimation (ME) within the ROI layer of the reference frame, and the other from the unrestricted ME in the overall reference frame. Simulation results show that the proposed scheme enhances the robustness of ROI scalability while maintaining coding efficiency.

关键词： Error resilience leaky prediction (LP) region-of-interest (ROI) scalable coding

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Client-driven selective streaming of multiview video for interactive 3DTV

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2007年第11期17卷 1558-1565页

作者： Kurutepe, Engin Civanlar, M. Reha Tekalp, A. Murat Tech Univ Berlin Inst Telecommun D-10587 Berlin Germany DoCoMo Labs Palo Alto CA 94304 USA Koc Univ TR-34450 Istanbul Turkey

We present a novel client-driven multiview video streaming system that allows a user to watch 3-D video interactively with significantly reduced bandwidth requirements by transmitting a small number of views selected according to his/her head position. The user's head position is tracked and predicted into the future to select the views that best match the user's current viewing angle dynamically. Prediction of future head positions is needed so that views matching the predicted head positions can be prefetched in order to account for delays due to network transport and stream switching. The system allocates more bandwidth to the selected views in order to render the current viewing angle. Highly compressed, lower quality versions of some other views are also prefetched for concealment if the current user viewpoint differs from the predicted viewpoint. An objective measure based on the abruptness of the head movements and delays in the system is introduced to determine the number of additional lower quality views to be prefetched. The proposed system makes use of multiview coding (MVC) and scalable video coding (SVC) concepts together to obtain improved compression efficiency while providing flexibility in bandwidth allocation to the selected views. Rate-distortion performance of the proposed system is demonstrated under different experimental conditions.

关键词： 3DTV multiview coding (MVC) scalable coding

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Source fidelity over fading channels: Performance of erasure and scalable codes

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IEEE TRANSACTIONS ON COMMUNICATIONS 2008年第7期56卷 1080-1091页

作者： Zachariadis, Konstantinos E. Honig, Michael L. Katsaggelos, Aggelos K. NW Univ Kellogg Sch Management Evanston IL 60201 USA NW Univ Dept Elect Engn & Comp Sci Evanston IL 60208 USA

We consider the transmission of a Gaussian source through a block fading channel. Assuming each block is decoded independently, the received distortion depends on the trade-off between quantization accuracy and probability of outage. Namely higher quantization accuracy requires a higher. channel code rate, which increases the probability of outage. We first treat an outage as an erasure, and evaluate the received mean distortion with erasure coding across blocks as a function of the code length. We then evaluate the performance of scalable, or multi-resolution coding in which coded layers are superimposed within a coherence block, and-the layers are sequentially decoded. Both the rate and power allocated to each layer are optimized. In addition to analyzing the performance with a finite number of layers, we evaluate the mean distortion at high Signal-to-Noise Ratios as the number of layers becomes infinite. As the block length of the erasure code increases to infinity, the received distortion converges to a deterministic limit, which is less than the mean distortion with an infinite-layer scalable coding scheme. However, for the same standard deviation in received distortion, infinite layer scalable coding performs slightly better than erasure coding, and with much less decoding delay.

关键词： source-channel coding scalable coding fading channel broadcast channel rate distortion

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