Methods and Arrangements for Image Processing

The present invention relates to methods and arrangements for compressing images. The invention is based on the fact that edge blocks contain much information in one direction (across the edge), but very little information in the other direction (along the edge). By encoding edges explicitly, it is possible to obtain a high quality to a very low cost for many blocks. A block is encoded by first specifying the orientation of the edge in the block, and then specifying the profile across the edge using a function with a small number of parameters.