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Image Processing, IET

Issue 6 • Date December 2009

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Displaying Results 1 - 5 of 5
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  • Adaptive deblocking filter for transform domain Wyner-Ziv video coding

    Page(s): 315 - 328
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (703 KB)  

    Wyner-Ziv (WZ) video coding is a particular case of distributed video coding, the recent video coding paradigm based on the Slepian-Wolf and Wyner-Ziv theorems that exploits the source correlation at the decoder and not at the encoder as in predictive video coding. Although many improvements have been done over the last years, the performance of the state-of-the-art WZ video codecs still did not reach the performance of state-of-the-art predictive video codecs, especially for high and complex motion video content. This is also true in terms of subjective image quality mainly because of a considerable amount of blocking artefacts present in the decoded WZ video frames. This paper proposes an adaptive deblocking filter to improve both the subjective and objective qualities of the WZ frames in a transform domain WZ video codec. The proposed filter is an adaptation of the advanced deblocking filter defined in the H.264/AVC (advanced video coding) standard to a WZ video codec. The results obtained confirm the subjective quality improvement and objective quality gains that can go up to 0.63-dB in the overall for sequences with high motion content when large group of pictures are used. View full abstract»

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  • Enhanced reconstruction algorithm for unidirectional distributed video coding

    Page(s): 329 - 334
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (527 KB)  

    Distributed video coding (DVC) is an emerging video coding technology that utilises the distributed source coding principles to build very low cost video encoders, yet with remarkable error resilience. In the most common DVC framework, the reconstruction function plays a vital role that has a direct impact on the output video quality. In this study, a novel algorithm is proposed for the reconstruction function, particularly focusing on a unidirectional DVC architecture. The proposed technique exploits the variations of the bit error rate of the Wyner-Ziv decoded bit stream and the assumed noise model in the side information stream. The simulation results show that the proposed algorithm yields a significant improvement of the objective and subjective video quality at no additional bit rate cost. View full abstract»

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  • Motion vector refinement in a Wyner--Ziv to H.264 transcoder for mobile telephony

    Page(s): 335 - 339
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (426 KB)  

    The authors develop a decoder/encoder system (transcoder) to solve the consumption constraint in the communications between end-user devices, when a new Wyner-Ziv (WZ)/H.264 framework is defined for being used in mobile-to-mobile environments. This approach is based on leaving to the devices only WZ video encoding and traditional video decoding; the lowest complexity algorithms in both paradigms. The system shifts the burden of complexity to the network, where an improved transcoder that reuses information between both paradigms is allocated. The WZ decoding motion vectors are used to reduce the H.264 motion estimation process. The proposed transcoder offers a complexity reduction up to 60- on average, without any rate distortion drop. View full abstract»

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  • Transform-domain distributed video coding with rate-distortion-based adaptive quantisation

    Page(s): 340 - 354
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1066 KB)  

    This study presents a transform-domain distributed video coding (DVC) system with a rate-distortion (R-D)-based adaptive quantisation (AQT) scheme. In the proposed system, the transform-domain Wyner-Ziv frame is divided into partitions and is adaptively quantised based on estimated local R-D characteristics for each partition. The R-D estimation is performed based on a correlation model between the original source information and the side information and can be applied at the decoder without adding complexity to the encoder. Coding results and comparisons with existing DVC schemes and with H.264/AVC interframe and intraframe coding are presented to illustrate the performance of the proposed system. View full abstract»

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Aims & Scope

The range of topics covered by IET Image Processing includes areas related to the generation, processing and communication of visual information.

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