LAUSR

In this paper, two reversible data hiding (RDH) methods for vector quantization (VQ)-compressed images are presented. In the first method, the difference-index table instead of the standard-index table is designed, and all difference indices are then classified into two groups, i.e., the to-be-mapped group and the candidate group, according to the occurrence frequencies of them. Afterwards, the mapping table between those two groups is adaptively constructed and used to serve for data embedding. Furthermore, another joint method is conducted by combining the standard-index based method and the difference-index based method, resulting in a better embedding performance. The experimental results confirm that both proposed methods, especially the joint method, are significantly superior to the most recent schemes in terms of the embedding capacity, bitrate and embedding rate.