A new postprocessing method for the block-based DCT coding based on the convex-projection theory

The block-based DCT coding has been adopted in image compression standards such as JPEG and MPEG. This type of coding causes some noticeable artifacts known as the blocking effect. Various postprocessing methods have been devoted to removing the blocking effect; however, these methods also unavoidably blur the decoded image. Removing the blocking effect while avoiding blurring is the main issue of the postprocessing. This paper presents a new postprocessing method based on convex-projection theory. This method is shown to have a good tradeoff for the blocking effects and the blurring effects.