Loop-filtering and post-filtering for low bit-rates moving picture coding

The decompressed images from highly compressed data have noticeable image degradations such as blocking artifacts, corner outliers, and ringing noise, because most image coding standards quantize the DCT coefficients of 8×8-pixel blocks independently. A loop-filtering algorithm and a post-filtering algorithm, which can reduce the quantization effects, are described, and the performance of both algorithms is compared with respect to the image quality, the computational complexity, and the compressed bit rates. Both the loop-filtering algorithm and the post-filtering algorithm reduce the quantization effects adaptively by using both DCT domain analysis and temporal information