An Adaptive Codewords Grouping Based Steganography for Index Images

Abstract

The practice of hiding secret messages into index-based images generally suffers from problems of image quality degradation and hiding capacity restriction. A steganographic scheme for index-based images using adaptive codeword groupings is proposed in this paper. The proposed scheme grouped the codewords in the codebook into sub-clusters, in terms of their relationship between the codewords for reducing the image distortion. Any size of the sub-cluster was allowed, so as to obtain the hiding capacity substantially, unlike other approaches in which the size of a sub-cluster was restricted to the power of 2. The proposed scheme was applicable as proven by experimental results. The higher hiding capacity was obviously extended; furthermore, the degradation of the stego-image was less and nearly disregarded. The average performance of the proposed scheme was much better as compared to other methods.