An Improved Lossless Information Hiding in SMVQ Compressed Images

Abstract

Reversible data hiding has always been the focus of researchers, because it can retrieve the cover image at the same time when obtaining secret message. Chang, Nguyen and Lin's scheme [1] proposed a reversible compression code hiding based on search order coding (SOC) algorithm and SMVQ. Based on their method, we have proposed some modification in this paper. In the embedding phase, we used SOC or SMVQ to encode the index, and used 1 bit as an indicator to indicate that the index is encoded. In the extraction phase, the receiver extracts the secret message and reconstructs the original SMVQ index us simple steps. Experimental results show that in the case of a state codebook with a size of 32, the compression rate of the proposed method was 0.26 bpp, which is better than the compression rate of 0.36 bpp, proposed by Chang et al.'s scheme. In the case of a state codebook with a size of 64, the compression rate of the proposed method was 0.27 bpp, which is still better than the compression rate of 0.41 bpp proposed by Chang et al.'s scheme. In the above two cases, embedding rate was kept same as the scheme proposed by Chang et al.