Role of scaling factor in robust digital watermarking

Abstract

Digital watermarking has been identified as an efficient tool to provide copyright authentication and protection of digital data. Robustness and Imperceptibility are the two key parameters in designing of watermarking system. It is always desired to design a watermarking system that provides excellent robustness to malicious attacks and the watermark is invisible to human eyes. The robustness and imperceptibility can be controlled by choosing an effective scaling factor. Scaling factor decides on the amount of insertion of watermark in the host image. Higher the value of scaling factor more visible the watermark will be in watermarked image, this leads to poor imperceptibility. However the increase in scaling factor leads to a more robust watermarking system. Finding a trade-off among both is the key issue of research in this area. This paper aims at describing the effect of selection of scaling factor on robustness and imperceptibility by taking different values of scaling factor during each watermarking process. The empirical analysis done in this work shows robustness can be improved at the cost of imperceptibility and vice-versa.