Efficient encoding and reconstruction of regions of interest in JPEG2000

The upcoming still image compression standard, called JPEG2000, has defined modes for encoding and decoding parts of the image that are considered of particular importance (Regions of Interest — ROFs), with better quality than the rest of the image. The ROI coding modes are based in the "scaling based method" and the generation of the ROI mask. In this paper we describe a fast method for generating the ROI mask for rectangular-shaped ROFs. A revised method of the general scaling based method that does not require any shape information to be transmitted at the decoder is then described. This makes possible to have arbitrary shaped region coding while the decoder is as simple as a non-ROI capable decoder is.