ABSTRACT
This chapter discusses the post-processing techniques developed for reducing artifacts in low bit rate image compression. It examines the discussion on the post-processing methods that have been developed to reduce the blocking and ringing artifacts. The chapter reviews the developments on ringing artifact reduction. Methods designed for discrete cosine transform and wavelet transform coding. In image and video coding, for a given encoding algorithm and a bit rate constraint, the quality of reconstructed images can be enhanced by pre filtering approaches. In the case of large quantization errors of wavelet coefficients in coded images, the decoded images still carry obvious artifacts among smooth regions and around sharp edges. The chapter describes how the proposed post filter works in such a way that it adaptively filters the transform coefficients based on the local signal characteristics to efficiently smooth out blocking artifacts, while preserving image details at the same time.
