Application of Random Amplitude-Phase Optical Encryption Based on Normal Speckle Pattern Interference in Digital Watermarking

In order to solve the problems of complex process of decryption and high cost when shifting the key codes of optical encrypted watermark, a method of applying double random amplitude-phase encryption to digital watermarking is introduced. The encrypted ESPI watermark is obtained by random amplitude-phase optical encryption based on normal speckle interference. An encrypted Fourier transform-ESPI watermarking scheme and an encrypted digital holography-ESPI watermarking scheme are introduced. Computer Simulation results show the feasibility of the new schemes. The compared results of image processing show that the encrypted ESPI watermark has good compatibility when combined with Fourier transform watermarking and digital holographic watermarking.