Colour image authentication based on a self-embedding technique

In the paper an approach for digital image authentication is described. The authentication process is achieved by means of a watermarking scheme that embeds an approximation of the image into itself. Specifically, the luminance of the image is inserted into the three colour channels, using a mapping function. The embedding process is implemented using a secret key k that maps the position of the pixel, where the luminance information is taken from, to the position of the pixel in which the watermark information is embedded. The quality of the watermarked images remains very high both subjectively and objectively. The proposed approach belongs to the category of semi-fragile techniques used for image authentication.