FAULT-TOLERANCE PROPERTIES OF A DOUBLE-PHASE ENCODING ENCRYPTION TECHNIQUE

We investigate the robustness of an image encryption technique that us es random phase encoding in both the input plane and the Fourier plane when the encrypted image has been distorted. The distortions include different types of noise, loss of encrypted data, and the binarization of the encrypted image. It is shown that decryption transforms the no ise added to the encrypted image to a wide-sense stationary additive w hite noise. Consequently, regardless of the type of the noise added to the encrypted image, the quality of the recovered image can be improv ed by processing techniques designed for filtering out additive white noise. The double-phase encryption technique distributes the input ima ge over the entire output plane, which provides robustness to the dist ortions due to toss of encrypted data. Regarding the binarization, it enables easy implementation and data compression while recovering imag es of good quality may be possible. (C) 1997 Society of Photo-Optical Instrumentation Engineers.