The blind digital watermarking algorithm based on Fresnel diffraction transform,phase encryption mask and discrete wavelet transform(DWT) is proposed.

The new image encryption algorithm was proposed based on multiple Fresnel diffraction transforms and phase encryption masks.

Discussion about the equivalency between fractional Fourier transform and Fresnel diffraction;

Blind information hiding technique using multiple Fresnel diffraction transforms;

The research of the fresnel diffraction of one-dimensional periodic grating and the measure of the grating constant;

Image scrambling method by using Fresnel transform;

They are done that computer simulation and performance analyzing of optical encryption based on Fresnel transform.

A method of the optical image encryption based on the frequency splitting domain and Fresnel domain is proposed,after the analysis of the fractional Fourier transform and Fresnel transform,by synthesizing the advantages of multi keys and lensless feature of the fractional Fourier transform and Fresnel transform in the optical image encryption system.

Based on Fresnel-Kirchhoff integral theorem of plan screen diffraction, asymrtotic approximation to special function and the method of stationary phase have been discussed, and the integral formula of optical-intensity distributed-function of single-slit Fresnel diffraction is introduceed.