A reversible watermarking for image content authentication based on wavelet transform

In the special field of anti-counterfeit authentication, such as medical archive protection, there is a problem of copyright infringement. To protect the privacy contents and achieve lossless recovery, we propose a reversible watermarking technology. In order to solve the problem, a wavelet transform-based reversible watermarking algorithm is proposed for image content authentication. To avoid the influence of tampering on the wavelet domain of the whole image, each block is transformed by wavelet transform as the carrier signal for carrying the watermark information. In the aspect of security, two watermarks are encrypted and scrambled by chaotic mapping with different keys, which increases the security of the watermark and the randomness of embedding. In tamper detection, different levels of detection and screening are used to improve the accuracy. When restoring the tampered area, two watermarks are used to reconstruct the category and feature information of the image block. Experimental results show that, after general tampering, constant mean tampering and paste tampering, the proposed watermarking algorithm can accurately detect and locate tampered areas and can restore the approximate original image information with high quality.