Quality and Spatial Scalabilities Implemented by Using Wavelet Image Coding

Abstract

A scalable image coding method is presented. Spatial scalability is implemented by using a multiresolution representation produced by a wavelet expansion. Quality scalability is implemented by using a multiprecision representation produced by multistage zero run-length coding after nonlinear quantization. The data rate is controlled by threshold values and/or spatial resolution in the wavelet expansion. The coding method owes its fine scalability and higher compression to multiresolution decomposition, nonlinear quantization, multistage zero run-length coding and arithmetic coding. In addition to the simplicity in coding, edges and outlines are well preserved without blocking noise at low bit rates. A few examples are also given.