A simple and efficient hierarchical image coder

In this paper we propose a simple image compression method that efficiently codes transform images. This work has been stimulated by the EZW and SPIHT image compression methods. However, the compression method we describe is not embedded in the sense employed previously, nor does it utilise the concept of a zerotree or related structure. The only characteristic of transform imagery utilised is that of energy clustering in frequency and in space. Two variants of the coding method are considered for image compression. One gives a hierarchical image code when employed with a discrete wavelet transform, while the other is suitable for block based coding.