Optical security system based on computer-generated hologram

A new image encoding and identification scheme is proposed for security verification by using a CGH (computer generated hologram), a random phase mask, and a correlation technique. The encrypted image, which is attached to the security product, is made by multiplying PCGH (phase CGH) with a random phase function. The random phase function plays a key role when the encrypted image is decrypted. The encrypted image can be optically recovered by a 2-f imaging system and automatically verified for a personal identification by a 4- f correlation system. Simulation results show the proposed method can be used for both the reconstruction of an original image and the recognition of an encrypted image.