一种对DCT编码图象的后处理算法

A Post Processing Algorithm of DCT coded Images

首先分析了“块效应”的形成原因、表现形式和测量方法，然后提出了一种自适应“块”边界平均方法并针对“块效应”在图象域的不同位置采用非线性空间移变滤波去除“块效应”

Block effect” prevalent in transform encoder images becomes increasingly objectionable as the required bit rate is reduced. The perceptual effect of this coding noise is highly dependent on the local behavior of the signal upon which it is superimposed, this coding noise can be divided three parts: Staircase noise, Grid noise, Texture noise. At first, we analyze why and how the“block effect” appears, and the measure of the 'block effect'. Then, we propose a processing algorithm named“adaptive block boundary average”and a computationally efficient edge classifier which is the basis of a non linear shift variant post-processing algorithm incorporating average filter and median filter.