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Cyclostationary error analysis and filter properties in a 3D wavelet coding framework

SIGNAL PROCESSING-IMAGE COMMUNICATION 2006年第8期21卷 653-675页

作者： Leonardi, Riccardo Signoroni, Alberto Univ Brescia Dept Elect Automat I-25123 Brescia Italy

The reconstruction error due to quantization of wavelet subbands can be modeled as a cyclostationary process because of the linear periodically shift variant property of the inverse wavelet transform. For N-dimensional data, N-dimensional reconstruction error power cyclostationary patterns replicate on the data sample lattice. For audio and image coding applications this fact is of little practical interest since the decoded data is perceived in its wholeness, the error power oscillations on single data elements cannot be seen or heard and a global PSNR error measure is often used to represent the reconstruction quality. A different situation is the one of 3D data (static volumes or video sequences) coding, where decoded data are usually visualized by plane sections and the reconstruction error power is commonly measured by a P-SNR[n] sequence, with n representing either a spatial slicing plane (for volumetric data) or the temporal reference frame (for video). In this case, the cyclostationary oscillations on single data elements lead to a global P-SNR[n] oscillation and this effect may become a relevant concern. In this paper we study and describe the above phenomena and evaluate their relevance in concrete coding applications. Our analysis is entirely carried out in the original signal domain and can easily be extended to more than three dimensions. We associate the oscillation pattern with the wavelet filter properties in a polyphase framework and we show that a substantial reduction of the oscillation amplitudes can be achieved under a proper selection of the basis functions. Our quantitative model is initially made under high-resolution conditions and then qualitatively extended to all coding rates for the wide family of bit-plane quantization-based coding techniques. Finally, we experimentally validate the proposed models and we perform a subjective evaluation of the visual relevance of the P-SNR[n] fluctuations in the cases of medical volumes and video coding

关键词： wavelet coding 3D data biorthogonal filters cyclostationary models bit-plane quantization quality assessment

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Analysis and optimization of wavelet-Coded Communication Systems

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2009年第2期8卷 563-567页

作者： Silveira, Luiz F. Q. Silveira Junior, Luiz G. Q. Assis, Fransco M. Pinto, Ernesto L. Ctr Fed Educ Tecnol Rio Grande Norte Dept Informat Technol BR-59015000 Natal RN Brazil Univ Fed Campina Grande Dept Elect Engn BR-58109970 Campina Grande Brazil Inst Militar Engn Dept Elect Engn BR-22290270 Rio De Janeiro Brazil

Since its advent, wavelet coding has been recognized as a promising technique for wireless transmission systems, especially due to its low decoding complexity and good performance over multipath fading. However, this technique requires unusual modulation schemes in order to be fully exploited. A BER analysis of wavelet-coded transmission systems over Rayleigh fading channels is presented in this work. This analysis is used in the design of novel signal, constellations for wavelet-coded systems by means of numerical performance optimization. Numerical results obtained from analysis and simulations show that the wavelet-coded systems derived herein have very good performance characteristics over fading channels.

关键词： Wireless communication systems wavelet coding flat-fading channels modulation design BER analysis

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Multiple description wavelet coding of layered video using optimal redundancy allocation

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EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING 2006年第1期2006卷 083542-083542页

作者： Boulgouris, Nikolaos V. Zachariadis, Konstantinos E. Kanlis, Angelos Strintzis, Michael G. Kings Coll London Div Engn Dept Elect Engn London WC2R 2LS England Northwestern Univ Kellogg Sch Management Evanston IL 60208 USA European Patent Off D-80298 Munich Germany Informat & Telemat Inst GR-57001 Thessaloniki Greece Univ Thessaloniki Dept Elect & Comp Engn GR-54124 Thessaloniki Greece

We present a wavelet-based framework for the encoding of video in multiple descriptions. Using the proposed methodology, the generation of multiple descriptions is performed so that drift is eliminated at the decoder regardless of the number of received descriptions. Moreover, the proposed framework is flexible in the sense that it allows the encoding of video into an arbitrary number of descriptions. We also present a thorough analysis of rate allocation issues and propose three algorithms for the optimal allocation of redundancy. Experimental results for the transmission of video using two descriptions demonstrate the efficiency of the proposed method. Copyright (C) 2006 Hindawi Publishing Corporation. All rights reserved.

关键词： redundancy multiples optimal allocation Videotapes wavelet coding allocation

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Locally adaptive passive error concealment for wavelet coded video

Locally adaptive passive error concealment for wavelet coded...

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Conference on wavelet Applications in Industrial Processing VI

作者： Rombaut, Joost Pizurica, Aleksandra Philips, Wilfried Univ Ghent Dept Telecommun & Informat Proc UGent TELIN IPI I B-9000 Ghent Belgium

ISBN: (纸本)9780819474988

In lossy packet networks such as the Internet, information often gets lost due to, e. g., network congestion. While these problems are typically solved by Active Error Concealment techniques such as error correcting codes, they do not always work for applications such as real time video. In these cases, Passive Error Concealment is essential. Passive error concealment exploits the redundancy in the video: lost data are estimated from their correctly received neighboring data. In this paper, we focus on wavelet based video coding. We compress video frames by dispersively spreading neighboring wavelet coefficients over different packets, and by coding these packets independently from each other. If a packet gets lost during the transmission, we estimate the missing data (wavelet coefficients in I-frames and P-frames, and motion vectors) with passive error concealment techniques. In the proposed method, we extend our earlier image concealment method to video. This technique applies a locally adaptive interpolation for the reconstruction of lost coefficients in the I-frames of wavelet coded video. We also investigate how the lost coefficients in P-frames can be reconstructed. For the reconstruction of lost motion vectors, we use the vector median filtering reconstruction technique. Compared to related video reconstruction methods of similar complexity, the proposed scheme estimates the lost data much better. The reconstructed video also looks better. As the proposed method is fast and of low complexity, it is widely usable.

关键词： Video reconstruction video communication error concealment wavelet coding

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Passive Error Concealment for wavelet-Coded I-Frames With an Inhomogeneous Gauss-Markov Random Field Model

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2009年第4期18卷 783-796页

作者： Rombaut, Joost Pizurica, Aleksandra Philips, Wilfried Univ Ghent Dept Telecommun & Informat Proc UGent TELIN IPI I B-9000 Ghent Belgium

In video communication over lossy packet networks (e.g., the Internet), packet loss errors can severely damage the transmitted video. The damaged video can largely he repaired with passive error concealment, where neighboring information is used to estimate missing information. We address the problem of passive error concealment for wavelet coded data with dispersive packetization. The reported techniques of this kind have many problems and usually fall in the reconstruction of high-frequency content. This paper presents a novel locally adaptive error concealment method for subband coded I-frames based on an inhomogeneous Gaussian Markov random field model. We estimate the parameters of this model from a local context of each lost coefficient, and we interpolate the lost coefficients accordingly. The results demonstrate a significant improvement over the reported related methods both in terms of objective performance measures and visually. The biggest improvement of the proposed method compared to the state-of-the-art in the field is the correct reconstruction of high-frequency information such as textures and edges.

关键词： Error concealment image communication image reconstruction video communication video reconstruction wavelet coding

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Image compression: Maxshift ROI encoding options in JPEG2000

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COMPUTER VISION AND IMAGE UNDERSTANDING 2008年第2期109卷 139-145页

作者： Tahoces, Pablo G. Varela, J. Ramon Lado, Maria J. Souto, Miguel Univ Vigo Escuela Super Ingn Informat Dept Comp Sci Orense 32004 Spain Univ Santiago Dept Elect & Comp Sci Santiago De Compostela 15782 Spain Univ Santiago de Compostela Dept Radiol Santiago 15782 Spain

Image compression can improve the performance of the digital systems by reducing time and cost in image storage and transmission without significant reduction of the image quality. Furthermore, the JPEG2000 has emerged as the new state-of-the art standard for image compression. In this paper, a Selective Coefficient Mask Shift (SCMShift) coding method is proposed. The technique, implemented over regions of interest (ROIs), is based on shifting the wavelet coefficients that belong to different subbands, depending on the coefficients relative to the original image. This method allows: (1) codification of multiple ROIs at various degrees of interest, (2) arbitrary shaped ROI coding, and (3) flexible adjustment of the compression quality of the ROI and the background. No standard modification for JPEG200 decoder was required. The method was applied over different types of images. Results show a better performance for the selected regions, when ROI coding methods were employed for the whole set of images. We believe that this method is an excellent tool for future image compression research, mainly on images where ROI coding can be of interest, such as the medical imaging modalities and several multimedia applications. (C) 2007 Elsevier Inc. All rights reserved.

关键词： image coding JPEG2000 region of interest wavelet coding

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Locally adaptive passive error concealment for wavelet coded images

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IEEE SIGNAL PROCESSING LETTERS 2008年第0期15卷 178-181页

作者： Rombaut, Joost Pizurica, Aleksandra Philips, Wilfried Univ Ghent Dept Telecommun & Informat Proc UGent TELIN IPI I B-9000 Ghent Belgium FWO Flanders Belgium

This letter presents a novel locally adaptive error concealment method for subband coded images. For each lost low-frequency coefficient, we estimate the optimal interpolation weights from its neighborhood. The calculation of the interpolation weights is optimized in the mean squared error sense, and it takes into account the errors that would arise by horizontally and vertically interpolating the available neighbors of the lost coefficient. Compared to methods of similar complexity, the proposed scheme estimates the lost coefficients more accurately: on average, the PSNR is increased by up to 4.5 dB. The reconstructed images also look better, and our method is fast and of low complexity.

关键词： error concealment image communication image reconstruction wavelet coding

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Multiresolution video object extraction fitted to scalable wavelet-based object coding

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IET IMAGE PROCESSING 2007年第1期1卷 21-38页

作者： Tab, F. A. Naghdy, G. Mertins, A. Univ Kurdistan Dept Elect & Comp Engn Sanandaj Iran Univ Wollongong Sch Elect Comp & Telecommun Engn Wollongong NSW 2522 Australia Med Univ Lubeck Inst Signal Proc D-23538 Lubeck Germany

To enable content based functionalities in video processing algorithms, decomposition of scenes into semantic objects is necessary. A semi-automatic Markov random field based multi-resolution algorithm is presented for video object extraction in a complex scene. In the first frame, spatial segmentation and user intervention determine objects of interest. The specified objects are subsequently tracked in successive frames and newly appeared objects/regions are also detected. The video object extraction algorithm includes discrete wavelet transform decomposition multi-resolution Markov random field (MRF)-based spatial segmentation with emphasis on border smoothness at different resolutions, and an MRF-based backward region classification that determines the tracked objects in the scene. Finally, a motion constraint, embedded in the region classifier, determines the newly appeared objects/regions and completes the proposed algorithm towards an efficient video segmentation algorithm. The results are applicable for generic segmentation applications, however the proposed multiresolution video segmentation algorithm supports scalable object-based wavelet coding in particular. Moreover, compared to traditional object extraction algorithms, it produces smoother and more visually pleasing shape masks at different resolutions. The proposed effective multiresolution video object extraction method allows for larger motion, better noise tolerance and less computational complexity.

关键词： object code extraction of object noise tolerance Scalability complexity classes Video object tracking objects wavelet coding Markov random fields

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Hierarchical dynamic range coding of wavelet subbands for fast and efficient image decompression

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2007年第8期16卷 2005-2015页

作者： Cho, Yushin Pearlman, William A. Sony Elect Inc San Jose CA 95112 USA Rensselaer Polytech Inst Elect Comp & Syst Dept Troy NY 12180 USA

An image coding algorithm, Progressive Resolution coding (PROGRES), for a high-speed resolution scalable decoding is proposed. The algorithm is designed based on a prediction of the decaying dynamic ranges of wavelet subbands. Most interestingly, because of the syntactic relationship between two coders, the proposed method costs an amount of bits very similar to that used by uncoded (i.e., not entropy coded) SPIHT. The algorithm bypasses bit-plane coding and complicated list processing of SPIHT in order to obtain a considerable speed improvement, giving up quality scalability, but without compromising coding efficiency. Since each tree of coefficients is separately coded, where the root of the tree corresponds to the coefficient in LL subband, the algorithm is easily extensible to random access decoding. The algorithm is designed and implemented for both 2-D and 3-D wavelet subbands. Experiments show that the decoding speeds of the proposed coding model are four times and nine times faster than uncoded 2-D-SPIHT and 3-D-SPIHT, respectively, with almost the same decoded quality. The higher decoding speed gain in a larger image source validates the suitability of the proposed method to very large scale image encoding and decoding. In the Appendix, we explain the syntactic relationship of the proposed PROGRES method to uncoded SPIHT, and demonstrate that, in the lossless case, the bits sent to the codestream for each algorithm are identical, except that they are sent in different order.

关键词： image coding low complexity random access scalability SPIHT wavelet coding

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Fast tree-based wavelet image coding with efficient use of memory

Fast tree-based wavelet image coding with efficient use of m...

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Conference on Visual Communications and Image Processing 2005

作者： Oliver, J Malumbres, MP Univ Politecn Valencia Dept Comp Engn Valencia 46022 Spain

ISBN: (纸本)0819459763

In this paper, we present a new wavelet image encoder that focuses on overcoming the main drawbacks of other wavelet based-image coders;their high memory requirements and complexity. In our proposal, we tackle these problems in both parts of the wavelet coder, both the DWT algorithm and the coding system. For the DWT, we propose the use of a line-based algorithm, in which we get rid of the wavelet coefficients as soon as they have been calculated. Some previous line-based proposals cannot be easily implemented, and here we describe a recursive algorithm that is implemented more easily. For the coding system, we use a tree-based coder. These coders have evidenced good Rate/Distortion (R/D) performance. However, it has not been clearly shown their excellent possibilities for fast processing of coefficients. Previous tree-based proposals need the entire image in memory to work and so they cannot be used in our system. Other wavelet encoders achieve good R/D performance, but exhibit high complexity. Our proposal is simpler and therefore faster. Numerical results show that the compression performance of our tree-based encoder is equal or better than state-of-the-art coders, such as SPIHT and JPEG 2000, except for highly detailed images. However, the real benefits of our proposal is shown in the amount of memory required, which is reduced drastically (in the order of 25 times less memory than SPIHT and more than 35 times less than JPEG 2000), and in its lower execution time (about four times lower than SPIHT, and more than 20 times lower than JPEG 2000). These results show that our encoder is a good candidate for many embedded systems and other memory-constrained environments, such as digital cameras and PDAs.

关键词： lossy image coding wavelet coding tree-based coding efficient memory usage fast processing

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