Adaptive post-processing for region-based fractal image compression

Summary form only given. Region-based fractal image compression (Chang et al., 1997) is an attractive variation of fractal image compression algorithm. By segmenting an image into variable sizes of quadtree blocks and then merging these blocks into regions, this algorithm has the potential to encode a still image with a very low bit rate. However, highly visible artifacts become annoying when the coding bit rate is low. A large number of studies have been done in the literature to improve the reconstructed image quality at low bit rates. In this paper, an adaptive image enhancement algorithm for region-based fractal image compression is proposed. By utilizing an algorithm to determine which pixels have to be smoothed, then applying different smoothing filters for various image areas, the proposed algorithm can significantly eliminate the annoying blocking artifacts for images coded with low bit rate.