On optimized histogram bin shifting reversible watermarking for color images

This paper extends to color images the optimized selection of bins for histogram shifting reversible watermarking. The proposed optimization scheme is tested on RGB and on other four color spaces, namely the ones used in JPEG2000, H.264/AVC and two other spaces recently proposed for lossless image compresion. Reversible color transforms to and from RGB exist for the considered color spaces. Experimental results for two well-known predictors, median edge detector and gradient-adjusted predictor are provided. The tests on RGB and on the four other color spaces show that RGB is not appropriate for optimized histogram bin shifting reversible watermarking.