Abstract: In order to achieve the goal of image authentication and protection simultaneously, we proposed a feature based robust digital image watermarking algorithm. I}he Hessian-Affine feature detector was used at first to search characteristic regions of an image, then embed the copyright watermark into these characteristic regions according to the local orientation of each pixel. Moreover, the remainder regions were applied for image authentication by using fragile watermarking method. The proposed watermark extract scheme is similar with the above embedding scheme, the procedure is executed blindly, for the host image is not needed. The experimental results in this paper show that the proposed watermarking algorithm can resist most removal and geometric attacks. Besides, changes of an image will be reflected in our hidden watermarks.

Key words: Digital watermark, Feature extraction, Copyright protection, Content authentication