Abstract
We present a geometric registration method for detecting digital watermarks from images. This method determines pixel-to-pixel correspondence between a copied image and its original image without referring to the original image. Feature points detected from the copied image and border lines determined to reside between the original image region and attached black region in the copied image are taken into account to determine the correspondence. The proposed method achieves locational accuracy of feature points within 2 pixels on condition that location error of detected feature points is up to 5 pixels in 720x480 copied images. The method reduces the length of video contents required to detect watermarks accurately by about 10 to 20 percent.
