Color image compression using multiwavelets with modified SPIHT algorithm

Abstract

Color Image compression is now essential for applications such as transmission and storage in data bases since color gives a natural and pleasing nature for any object. For still image compression, the ‘Joint Photographic Experts Group’ standard has been established by International Standards Organization (ISO). The performance of existing image coding standards generally degrades at low bit-rates because of the underlying block based Discrete Cosine Transform (DCT) scheme. Over the past decade, the success of wavelets in solving many different problems has contributed to its unprecedented popularity. Due to implementation constraints, scalar wavelets do not possess all the properties which are needed for a better performance in compression. The new class of wavelets, called multiwavelets, which possess more than one scaling filters overcomes this problem. The objective of this paper is to develop an efficient color compression scheme and to obtain better quality and higher compression ratio through multiwavelet transform and embedded coding of multiwavelet coefficients through Set Partitioning In Hierarchical Trees (SPIHT) algorithm. A comparison of the best known multiwavelets is made to the best known scalar wavelets. Both quantitative and qualitative measures of performance are examined.