Pixel-based fragile image watermarking based on absolute moment block truncation coding

A pixel-based fragile image watermarking method based on s absolute moment block truncation coding (AMBTC) is proposed in this paper. To enhance the readability of the tampered image, we apply pixel concept to design pixel-based tampering detection and content recovery mechanisms. In the proposed scheme, recovery information is derived from the AMBTC compression codes of the original image, and authentication codes are generated by a pseudo random generator (PRG). Both data are then discretely embedded into the two least significant bits (LSBs) of pixels in the original image with turtle shell-based data hiding method. Therefore, each non-overlapped pixel pair in a watermarked image has 2 bits of recovery information and 2 bits of authentication code. When the recipient suspects that the received image may have been tampered with, the hidden authentication code can be used to locate tampered pixels, and then the hidden recovery information can be extracted and then used to restore the tampered pixels.