Lossless and nearly lossless compression for high quality images

While a losslessly compressed facsimile image might require 20,000 bytes of storage, a losslessly compressed color high resolution scan of the same sized document might require 200,000,000 bytes of storage. This factor of 10,000 in the image size necessitates more than just better compression, it requires a change in viewpoint about compression, A compression system for high quality images must provide a way to access only the required data rather than decompressing all the data and then selecting the desired portion. Furthermore, a high quality image compression system should be able to provide the best possible images for output devices which as of yet have not been manufactured. Finally, a high quality compression system should allow decompression and recompression without continual degradation of the image. This paper describes technologies including a reversible color transform, a reversible wavelet transform, a doubly embedded context model, and a ''parseable'' file format, which work together to provide solutions for high quality imaging needs.