A Polar Complex Exponential Transform-Based Zero-Watermarking for Multiple Medical Images with High Discrimination

Zero-watermarking is one of the solutions for image copyright protection without tampering with images, and thus it suitable medical which commonly do not allow any distortion. Moment-based zero-watermarking robust against both processing geometric attacks, but discrimination watermarks often ignored by researchers, resulting in high possibility that host images fake cannot be distinguished verifier. To this end, paper proposes a PCET- (polar complex exponential transform-) based scheme on stability relationships between moment magnitudes same order repetition, can handle multiple simultaneously. The first calculates PCET each an group. Then, repetition are compared to obtain content-related features. All features added together Finally, extracts feature vector chaos system takes bitwise XOR scrambled watermark generate zero-watermark. produces resistance various attacks low similarity among different images. In addition, one-to-many mapping bits reduces number moments involved, only computation time also further improves robustness. experimental results show proposed meets performance requirements robustness, discrimination, capacity, outperforms state-of-the-art methods terms computational under payloads.