A new reversible watermarking of 3D models based on ratio expansion

In this paper, a new reversible watermarking method based on ratio expansion for 3D mesh models is proposed. The distances between a vertex and its adjacent vertices are calculated respectively, each of which is then divided by the same reference value to form a series of ratios. Each ratio divided by 2
^N
is multiplied by 10
^M
and then the integer part of it is expanded to embed watermark information. The parameter M is adjusted to assure the invisibility. After translation, rotation and scaling, we could still extract the watermark and original model completely. With appropriate M and N, our algorithm is of good invisibility and high embedding capacity as well as robustness against some noises.