Line watermark embedding method for affine transformed images

This paper describes a new content-based affine-invariant digital watermarking technique. With the proposed embedding and detecting scheme, the watermark patterns are located along the lines constructed from pairs of imagepsilas salient points. By using a pair of feature points, the method can perform a search for a watermark faster than other schemes that require at least three correspondence points. The problem of limited embedding capacity, which results in weak robustness, is addressed. A solution to increase the method robustness using multiple line averaging is described. In addition, by utilizing a certain constraint on cropping pattern, the method can be used to provide an estimation of a cropping boundary.