Apply phase information in RST image watermarking

The paper presents a novel digital image watermarking scheme, based on the Fourier-Mellin transform, that is invariant to rotation, scaling, and translation (RST). We embed the watermark in the log-polar mappings of the Fourier magnitude spectrum of the original image and use the phase information of the original image to rectify the watermark positions. The scheme avoids computing inverse log-polar mapping (ILPM), and therefore preserves the image quality. Evaluations demonstrate that the scheme is invariant to rotation and translation, and sufficiently invariant to scaling transformation, and very robust to JPEG compression.