Watermark extimation through local pixel correlation
Matthew J. Holliman, Nasir D. Memon, Minerva M. Yeung · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1999
Many invisible watermarking schemes can be modeled as the addition of a watermark signal to an image, yielding a watermarked variant perceptually similar to the original image. In this paper, we describe a method by which an attacker, given only an image watermarked with such a technique, can attempt to construct an approximation to the watermark. The technique estimates an embedded signal by taking advantage of the inter-pixel correlation typically found in natural images, thereby allowing for a method of both watermark removal and watermark forgery. Furthermore, the approach is computationally inexpensive, making it suitable for attacks on proposed video watermarking schemes.