Watermarking color histograms

Abstract

In this paper we give a method for watermarking color histograms. Color histograms have been known M. J. Swain et al., (1991) to be robust to rotations and other geometric transformations. If the watermark can be embedded in such geometry invariant representations it should survive geometric transformations. The difficulty in watermarking color histograms is that they have a nonlinear relationship with the pixel representation. Therefore it is not clear how to get a watermarked image given its watermarked histogram. We give a method for watermarking color histograms that uses earth mover distance (EMD) to modify an image to a target histogram. We conduct extensive experiments to test our method.