线性及非线性滤波在低码率可视电话图像压缩编码中的应用

本文针对用自适应ＤＣＴ压缩编码方法所产生的低码率可视电话恢复图像中所存在的严重的方块效应进行处理．通过对原始图像进行前滤波和对编码后的图像的子块边界进行后滤波的方法，使单色图像在０．２５ＢＩＴ／ＰＥＬ比特率条件下得到较好的图像质量．同时提出了一种参照视觉掩盖效应所形成的新的块效应评估准则，在计算机模拟试验中，对存在着不同程度方块效应的编码后图像进行了方块效应测试，得到了与主观评价相符合的结果．

The application of the linear and nolinear filter to the image compression coding at a low bit rate videotelephone picture

n this paper a method of reduction of the serious blocking effect existing in a low bit ratevideotelephone picture resulting from the method of Adaptive DCT Image Coding is discussed. Theimproved monochrome television image below 0. 25bit/pel is obtained by using prefilter to theoriginal image and the postfilter to the subimage boundaries of the coded image. According to thevisibility threShold,a new appraisal method to the block effect is proposed. The result of our methodis coincided with subjective assessment.