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16 September 1996 Quality improvement of low-data-rate compressed video signals by pre- and postprocessing
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In this paper a technique for improving the image quality of block-based video coders is presented which combines the following pre- and postprocessing steps: Before the coding process, the image sharpness is enhanced by applying a special prefilter to the original image. By this means a possible degradation of the image sharpness by the coder is compensated. The decoder output is smoothed by a lowpass filter which reduces artifacts such as block discontinuities. Secondly, the quantization error of the frequency DCT coefficients is reduced by predicting AC coefficients based on the mean values of the neighboring image blocks. This step improves the luminance function within the blocks. While the original sequences show coarse blocking patterns, the images processed by this technique look smooth on the overall with well-preserved local edge structures. The tool supports all standardized DCT codecs, such as MPEG-1/2 or H.261/3.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Robert Kutka, Andre Kaup, and M. Hager "Quality improvement of low-data-rate compressed video signals by pre- and postprocessing", Proc. SPIE 2952, Digital Compression Technologies and Systems for Video Communications, (16 September 1996);

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