Cross-talk free image encryption and watermarking by digital holography and random composition

• Published in: Optics communications 2007-01, Vol.269 (1), p.47-52
• Main Authors: Meng, X.F., Cai, L.Z., He, M.Z., Dong, G.Y., Shen, X.X.
• Format: Article
• Language: English
• Subjects: Digital image processing; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Holographic interferometry; Holographic interferometry; other holographic techniques; Holography; Image encryption and watermarking; Image forming and processing; Image reconstruction; Image reconstruction; tomography; Imaging and optical processing; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Interferometers; Optical instruments, equipment and techniques; Optics; Physics
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2006.07.032

In previous image watermarking methods an encoded host image and a watermark image are usually directly added, consequently the two images have cross-talk in the decryption step. To eliminate this effect, we propose a novel method based on digital holography, in which all the image pixels of the two sets of holograms resulted from two hidden images are rearranged and integrated into one set of composite holograms with a random scattering matrix (RSM). In decryption the use of this matrix can ensure the exact retrieval of each hologram, and then the perfect reconstruction of each image without cross-talk noise can be achieved. The feasibility of this method and its robustness against occlusion and additional noise are verified by computer simulations with phase-shifting interferometry and double random-phase encoding technique. This approach is suitable for both two- and three-dimensional images, and the additional RSM as a key provides a much higher level of security.