A high capacity reversible multiple watermarking scheme for medical images

Reversible data hiding schemes can be used to embed sensitive personal information in a generic signal without any loss of either the embedded or the host information. Multiple watermarking allows embedding different marks at different stages into the host media. This paper proposes a high capacity reversible multiple watermarking scheme for medical images based on integer-to-integer wavelet transform and histogram shifting. The novelty of the proposed scheme is that it uses a scalable location map and incorporates efficient stopping conditions on both wavelet levels and different frequency subbands of each level to achieve high capacity payload embedding, high perceptual quality, and multiple watermarking capability. Results show that the proposed method attains high perceptual quality in high capacity rates for the medical images. The improvement in the visual quality of the watermarked images along with the possibility of multiple watermark embedding indicate that this algorithm is capable of rendering a wide range of applications that aim at security and privacy protection in the medical field.