Based on the analysis of conventional phase difference detection method,a new algorithm of phase difference detection is presented according to Fourier series decomposition method and the characteristic that inner product of two orthogonal vectors in a linear space is zero.

The main methods include:1) Invariant local feature regions are generated using locally most stable feature points of images;2) An approach is proposed to rapidly find the best image regular geometric flow in these local feature regions;and 3) An orthogonal vector is designed to extract the watermark blindly.

This paper presents a new perceptual digital watermarking scheme based on human vision system,discrete wavelet transform and orthogonal vector.