Robust Image Watermarking for Camera-captured Image using Image Registration Technique

This paper addresses the difficulty of extracting and/or verifying a watermark signal from watermarked image contained within poster. We consider a situation where an image owner tries to extract his/her embedded watermark from a camera-captured image having unauthorized image inside. This image normally contains rotation, scaling, and translation and perspective distortions from the processes of printing and camera-capturing resulting in an inaccuracy of the extracted watermark. We thus propose in this paper a new watermarking method for poster resilient to such distortions. In the embedding process, embedding technique based on pixel modification is used to embed watermark. In the extraction process, an automatic image registration technique based on projective transformation is used to diminish those distortions. The experimental results show effectiveness of our proposed method.