Adaptive postprocessors with DCT-based block classifications

In this paper, an adaptive postprocessor figured with discrete cosine transform (DCT)-based block classification to effectively remove the so-called blocky effect from compressed video sequences is proposed. The proposed DCT-based detection algorithms for both intraframes and interframes require much lower computation complexity than the spatial-domain approaches. In order to preserve the edge information, the adaptive postprocessor is also designed with a DCT-based edge detection mechanism such that a one-dimensional median filter can be adaptively adjusted to match with the edge orientation. Simulation results show that the proposed DCT-based detection algorithms accurately classifies smooth, edge, or nonsmooth blocks to help the adaptive postprocessor to effectively remove the blocky effect and sharply preserve the edge information.