Wavelet-based reversible watermarking system for integrity control and authentication in tele-ophthalmological applications

In numerous applications, such as in the areas of law enforcement and medical imaging systems, together with perceptual transparency, it is required to reverse the modified media back to the original without any deformation, after the secret data are regained for some legal deliberations. This paper proposes a completely reversible watermarking system with enhanced imperceptibility, robustness, and capacity for colour medical images which can effectively check the unlawful utilisation of the medical images with no affect to medical information and its visual quality. The proposed algorithm depends on transforming non-overlapping blocks of the host image using wavelet transform and is completely blind. The proposed technique attains high values of peak signal to noise ratio (PSNR) of watermarked image and high values of normalised correlation (NC) of the extracted watermark and recovered original image. State-of-the-art comparison shows that the proposed scheme has advantages over the existing techniques. This scheme may be proficient in providing a broad range of applications that aims at security and privacy protection in the medical field. The scheme can also be helpful for the purpose of identification of fundus images for storage in distributed medical databases and tele-ophthalmological applications.