This study investigates the design and performance of a spatial domain image encoding scheme that adapts to the localized statistical structure of an image. An adaptive differential pulse code modulation (dpcm) image ...
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ISBN:
(纸本)0819424358
This study investigates the design and performance of a spatial domain image encoding scheme that adapts to the localized statistical structure of an image. An adaptive differential pulse code modulation (dpcm) image coding system operates on an image that has been preprocessed into segments of variable size, square blocks. Each block is separately encoded by a dpcm system whose parameters have been obtained based upon an underlying nonstationary image model fitted to the block. The source coding performance of the adaptive dpcm algorithm proposed in this study has been found to result in an improvement of 2.5 dB, or greater, compared to that obtained using a nonadaptive, conventionally designed dpcm encoder/decoder pair when operating at low bit rates (i.e., 3 bits/pixel or less). Reconstructed images obtained in this study are of perceptually higher-quality due to the adaptive encoding system design being based on the more realistic assumption of nonstationary statistics. Specifically, experiments have revealed that reconstructed edges within local regions of the image are sharper providing an overall improvement in a viewers subjective assessment of global image quality.
This paper proposes an image partition based approach to enhance side information quality in low delay distributed video coding (DVC). The proposed method employs a checkerboard pattern to group blocks of the Wyner-Zi...
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ISBN:
(纸本)9781424445936
This paper proposes an image partition based approach to enhance side information quality in low delay distributed video coding (DVC). The proposed method employs a checkerboard pattern to group blocks of the Wyner-Ziv frame into two sets, where one set is dpcm encoded and the other set is DVC encoded. These two sets are encoded independently and decoded successively. At decoder, dpcm set will be first reconstructed. Then the temporal concealment tool, such as boundary matching algorithm, is performed to conceal blocks in the DVC set. An improved side information is subsequently obtained for DVC set, based on which a higher compression can be achieved. Simulation results indicate that a more promising performance can be achieved when compared with existing motion extrapolated approach.
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