Scalable Image Compression Algorithms with Small and Fixed- Size Memory

Abstract

Abstract The SPIHT algorithm is characterized by low computational complexity, good performance, and the production of an embedded bitstream that can be decoded at several bit-rates with image quality enhancement as more bits are received. However, it suffers from the enormous computer memory consumption due to utilizing linked lists of size of about 2–3 times the image size to save the coordinates of the image pixels and the generated sets. In additions, it does not exploit the multi-resolution feature of the wavelet transform to produce a resolution scalable bitstream by which the image can be decoded at numerous resolutions (sizes). The Single List SPIHT (SLS) algorithm resolved the high memory problem of SPIHT by using only one list of fixed size equals to just 1/4 the image size, and an average of 2.25 bits/pixel. This paper introduces two new algorithms that are based on SLS. The first algorithm modifies SLS to reduce its complexity and improve its performance. The second algorithm, which is the major contribution of the work, upgrades the modified SLS to produce a bitstream that is both quality and resolution scalable (highly scalable). As such, the algorithm is very suitable for the modern heterogeneous nature of the Internet users to satisfy their different capabilities and desires in terms of image quality and resolution.