A Novel Robust Watermarking Algorithm for Encrypted Medical Image Based on Bandelet-DCT

Abstract

Digital watermarking technology is a good way to solve the problem of image information security. However, in previous studies, watermark is encrypted, but the host image is not encrypted, which causes the leakage of the private information of the images themselves. When the carrier image is a medical image, more attention should be paid. Therefore, a new robust zero-watermarking algorithm based on Bandelet-DCT (Bandelet Transform and Discrete Cosine Transform) for medical image in the encryption domain of DWT-DCT (Discrete Wavelet Transform and Discrete Cosine Transform) is proposed. Firstly, the original medical image is encrypted in a transform domain based on a Logistic chaotic map to enhance the security of the original medical image. Then Bandelet-DCT is applied to extract the feature sequences of encrypted medical images which were preprocessed by SIFT (Scale Invariant Feature Transform). In the stage of watermarking embedding and extraction, zero-watermarking technology is implemented to ensure that the region of interest of the medical image remains unchanged, and evaluate the robustness of the algorithm through the correlation coefficient between the original watermark and the attacked watermark. Experimental results show that the proposed algorithm has strong robustness and can effectively solve the problem of information leakage. It has a strong anti-attack ability, good robustness, and certain application prospects.