Stereo image watermarking scheme for authentication with self-recovery capability using inter-view reference sharing

Advances in three dimensional video is a strong stimulus for research in authentication of stereo image to avoid illegal modification. In this paper, a stereo image watermarking scheme is proposed for authentication with self-recovery capability using inter-view reference sharing. A mechanism of inter-view reference sharing in stereo image pairs is designed to reduce bits for recovery reference generation compared with independent references. Discrete wavelet transform coefficients are employed to generate the references, and two reference copies of each block embedded in two different mapping blocks are prepared for recover tamper. Moreover, detail information from high frequency coefficients is also embedded so as to improve the quality of tamper recovery. For the purpose of resisting collage attack and increasing the probability of tamper detection, disparities between pairs of matched blocks are checked to conduct tamper detection. Experimental results show that the proposed scheme can detect tampered blocks with the probabilities of more than 99 % after collage attack. When stereo images are cropped from 10 to 70 % with randomly tampering, they are recovered without losing main visual information and qualities of recovery are better than those of existing monocular image watermarking schemes extended to stereo images.