Hidden Based On Phase-encoded Optical Information Technology Research

Optical information processing (OIP) combines the characteristics of having large-capability, high-speed and parallelism. The most important thing is that the information can be hided in many parameters such as phase, wavelength, special frequency. So it is an effective method of optical image security.In this paper, there are two methods of hiding the important information into two phase masks. one is the optical verification system based on joint transform correlator. This method encodes the key image and predefined images with the phase retrieve algorithm. Once put the encoded information on the input plane, the predefined images will be gotten on the output plane with which the system can do something such as verification and recognition. The validity and feasibility of this method is proved by the computer simulation; The other is optical verification system based on equal thickness interference. The output of this system is the interference pattern of the two phase masks. The correct image could not be gotten without knowing the phase distributing of the two masks. The validity and feasibility of this method is proved by the computer simulation.In addition, the method of making watermark with optical theory is also investigated in this paper. An image digital watermark technique is proposed based on Phase retrieve algorithm. The image to be hidden is transformed with Phase retrieve algorithm into the pure-phase spectrum distribution. The phase component of the pure-phase spectrum distribution is considered as the watermark information. Two ways of adding the watermark information to the host image directly are introduced respectively in detail. From the results of the PC simulation and the analysis for them, the validity of this image digital watermark technique is demonstrated.At last, all the works above are summarized and the emphases in future investigation are also put forward.