Reversible data hiding with high payload based on referred frequency for VQ compressed codes index

In 2007, Chang et al. proposed a reversible data hiding scheme for secret communication that hides secret information in the compression codes of a cover image, but their scheme has low hiding capacity and introduces extra m bits to reverse the original vector quantization (VQ) index of the cover image after the secret data are extracted. Instead of introducing m bits (where the size of the codebook is m bits) and using only one-third of the VQ indices of the cover image to hide the secret bit, we propose using only one bit to distinguish between indices of two clusters (i.e., cluster2 and cluster3). Not only the indices in cluster1 but also those in cluster2 and cluster3 can hide the secret bits. Our proposed scheme reduces the number of extra bits and increases the hiding capacity. The experiment results clearly showed that our proposed scheme outperforms Chang et al.׳s hiding scheme.