31 July 2006 Directional filtering for block recovery using wavelet features
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Proceedings Volume 5960, Visual Communications and Image Processing 2005; 59600Z (2006) https://doi.org/10.1117/12.631414
Event: Visual Communications and Image Processing 2005, 2005, Beijing, China
Abstract
When images compressed with block-based compression techniques are transmitted over a noisy channel, unexpected block losses occur. Conventional methods that do not consider edge directions can cause blocked blurring artifacts. In this paper, we present a post-processing-based block recovery scheme using Haar wavelet features. The adaptive selection of neighboring blocks is performed based on the energy of wavelet subbands (EWS) and difference between DC values (DDC). The lost blocks are recovered by linear interpolation in the spatial domain using selected blocks. The method using only EWS performs well for horizontal and vertical edges, but not as well for diagonal edges. Conversely, only using DDC performs well for diagonal edges with the exception of line- or roof-type edge profiles. Therefore, we combine EWS and DDC for better results. The proposed directional recovery method is effective for the strong edge because exploit the varying neighboring blocks adaptively according to the edges and the directional information in the image. The proposed method outperforms the previous methods that used only fixed blocks.
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Seung Hwa Hyun, Il Kyu Eom, Yoo Shin Kim, "Directional filtering for block recovery using wavelet features", Proc. SPIE 5960, Visual Communications and Image Processing 2005, 59600Z (31 July 2006); doi: 10.1117/12.631414; https://doi.org/10.1117/12.631414
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