Abstract
Spherical surface (or cylinder) is considered to be regarded as the observing plane in an optical system. Several original images are placed at different directions on a sphere (or cylinder). The diffraction model between two slant planes is proposed to construct the propagation relation equation of the light field expressed by two images. The interference of two optical beams is used for hiding a secret pattern into two phase-only masks. The geometric parameters of the system (orientation and distance) can serve as an additional key for enhancing security. The numerical simulation results are made in order to validate the performance of the multiple encryption schemes.
Funding
This work was supported by the National Natural Science Foundation of China [grant number 11104049], [grant number 61377016], [grant number 61371044]; the National Basic Research Program of China [grant number 2013CBA01702]; the Program for New Century Excellent Talents in University [grant number NCET-12-0148]; the Opening Foundation by State Key Laboratory of Information Security [grant number 2013-1-7]; the China Postdoctoral Science Foundation [grant number 2013M540278]; the Fundamental Research Funds for the Central Universities [grant number HIT.BRETIII.201406].