A code division multiplexing and block classification-based real-time reversible data-hiding algorithm for medical images

Abstract

This paper proposes a novel reversible data hiding (RDH) scheme for medical image based on block classification and code division multiplexing (CDM) in frequency domain. In this scheme, the original medical image is divided into non-overlapping blocks and classified into texture and smooth groups by calculating the mean square error of each block. The texture blocks are then transformed into the frequency domain with integer-to-integer discrete wavelet transform method, and the secret data are embedded into the detail sub-bands of the chosen texture blocks with CDM-based RDH algorithm. Consequently, the detail information of medical image is clarified and the data-embedding capacity is enlarged. Simultaneously, as the spreading sequences employed for data embedding are orthogonal to each other, when the secret message is repeatedly embedded into the cover image, most of the elements of spreading sequences are mutually canceled, which enables the proposed scheme to obtain high visual quality even at large data-embedding capacities. Moreover, on the receiver side, only the receiver with the correct data-embedding and block classification parameters can reconstruct the secret message and the cover image completely; thus, the security of RDH is guaranteed. Experimental results have demonstrated that the proposed scheme can yield better overall performance than other state-of-the-art RDH schemes on medical images.