A steganalytic algorithm for 3D polygonal meshes

We propose a steganalytic algorithm for watermarks embedded by Cho et al.´s mean-based algorithm [1]. The main observation is that while in a clean model the means of Cho et al.´s normalized histogram bins are expected to follow a Gaussian distribution, in a marked model their distribution will be bimodal. The proposed algorithm estimates the number of bins through an exhaustive search and then the presence of a watermark is decided by a tailor made normality test. We also propose a modification of Cho et al.´s algorithm which is more resistant to the steganalytic attack and offers an improved robustness/capacity trade-off.