Novel reversible data hiding scheme for Two-stage VQ compressed images based on search-order coding

In this paper, a novel reversible data hiding scheme for Two-stage VQ (Vector quantization) compressed images based on SOC (Search-order coding) scheme is proposed. Two-stage VQ improves VQ by obtaining better reconstructed image and generating indices with higher correlation. The difference image, as the input of Two stage VQ, is produced by employing the first codeword in state codebook and the current image block. The main idea of SOC method is exploiting the correlation of indices to derive better compression performance. The combination of SOC and data hiding can achieve both high compression rate and high embedding capacity. Since Two-stage VQ can achieve indices with higher correlation, this advantage is applied to enhance the data hiding performance. Moreover, the cover image can be reconstructed by the receiver without using any side information. To show the superiority of our proposed scheme, several state-of-the-art schemes designed for compression domain are cited for comparison.