Affine invariant watermarking algorithm using feature matching

Geometric attacks are among the most challenging problems in present day watermarking. Such attacks are very simple to implement yet they can defeat most of the existing watermarking algorithms without causing serious perceptual image distortion. In this research, a novel method to estimate the geometric manipulation is reported. The point pattern matching measure is computed for estimating geometric manipulation. The reference point patterns (i.e., a triple) are computed from feature ellipse of the original image. The proposed scheme does not require the original image because reference triple information of the original image has been contained in the secret key. Novel algorithm has been proved its robustness to geometric attacks through experiments results.