A verification system for still images that embeds a watermark so that no visual artifacts are created in the images and thus maintains the visual quality of the image. The algorithm embeds information in an uncompressed image so as to later detect the alteration of the image, as well as the location...http://www.google.com/patents/US6246777?utm_source=gb-gplus-sharePatent US6246777 - Compression-tolerant watermarking scheme for image authentication
