Objective image quality measure for block-based DCT coding

Abstract

The block-based discrete cosine transform (DCT) coding has been adopted in image or video compression standards such as JPEG and MPEG. The coding method produces a noticeable artifact for very low bit rate application known as the blocking effect. In the literature, there have been various postprocessing methods proposed to reduce the blocking effect. However, there is no suitable objective tests showing the performance of these various methods. This paper proposes a new objective measure for evaluating the postprocessing methods. The measure will be evaluated to have a consistent result with the subjective measure. The objective measure also provides an analytical result on the underlying sources of artifacts.