An Algorithm for Wavelet-Based Storage Compression and Fast Subregion Retrieval

In an image browsing environment there is need for a design that allows viewing image subregions in progressively higher resolutions. We describe a storage scheme that accomplishes good image compression ratios, while providing fast image subre-gion retrieval in various resolutions. This storage scheme is applied on the quantized coeecient matrices obtained from the application of wavelet transforms to images. Our encoding algorithm is based on quadtrees to provide compression and region indexing, coupled with Huuman coding to further improve the compression ratios. We provide results of experiments performed in a digital library environment to demonstrate the eeectiveness of our scheme.