Codebook Partition Based Steganography without Member Restriction

The practice of concealing secret messages into index-based images has generally suffered from problems of image quality degradation and hiding capacity restriction. A steganographic scheme using an improved codebook partition is proposed in this paper. The proposed scheme partitions the codebook into different member sub-clusters in terms of their similarity between the codewords for increasing the hiding capacity and reducing the image distortion. Any size of a sub-cluster was allowed in the proposed scheme, so as to improve the traditional approaches in which the size of a sub-cluster was restricted to the power of two. As a result of this revised scheme, an increased hiding capacity and a reduction in image distortion are obtained, as indicated from experimental results. The average performance of the proposed scheme is superior to that of those standard methods.