Blind biometric watermarking based on contourlet transform

We present a blind biometric watermarking algorithm based on Contourlet transform in this paper. The host image is decomposed into a series of multiscale, local and directional subimages using Contourlet transform. A high frequency directional sub-band which has the highest energy is used for watermarking embedding . At the same time, the original binary watermark is scrambled by two-dimensional Arnold transform, and then embedded into the selected directional sub-band. The sign of the contourlet coefficients are modified depending on the watermark bit. The watermark retrieving algorithm is a blind detection process, and it does not need the original image. The experimental results show that the proposed watermarking algorithm is able to resist attacks, and it is invisible and robust.