DWT-based technique for spatio-frequency masking of digital signatures
Mauro Barni, F. Bartolini, Vito Cappellini, Alessandro Lippi, Alessandro Piva · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1999
The growth of the Internet and the diffusion of multimedia applications requires the development of techniques for embedding identification codes into images, in such a way that it can be granted their authenticity and/or protected the copyright. In this paper a novel system for image watermarking, which exploits the similarity exhibited by the Digital Wavelet Transform with respect to the models of the Human Visual System, for robustly hiding watermarks is presented. In particular, a model for estimating the sensitivity of the eye to noise, previously proposed for compression applications, is used to adapt the watermark strength to the local content of the image. Experimental results are shown supporting the validity of the approach.