The performance of fully phase- and amplitude-based encryption processors is analyzed. The effects of noise perturbations on the encrypted information are considered. A thresholding method of decryption that further reduces the mean-squared error (MSE) for the fully phase- and amplitude-based encryption processes is provided. The proposed thresholding scheme significantly improves the performance of fully phase- and amplitude-based encryption, as measured by the MSE metric. We obtain analytical MSE bounds when thresholding is used for both decryption methods, and we also present computer-simulation results. These results show that the fully phase-based method is more robust. We also give a formal proof of a conjecture about the decrypted distribution of distorted encrypted information. This allows the analytical bounds of the MSE to be extended to more general non-Gaussian, nonadditive, nonstationary distortions. Computer simulations support this extension.
© 2000 Optical Society of America
(070.0070) Fourier optics and signal processing : Fourier optics and signal processing
(070.4560) Fourier optics and signal processing : Data processing by optical means
(100.0100) Image processing : Image processing
(110.3000) Imaging systems : Image quality assessment
(110.4280) Imaging systems : Noise in imaging systems
Bahram Javidi, Nasser Towghi, Nabíl Maghzi, and Steven C. Verrall, "Error-Reduction Techniques and Error Analysis for Fully Phase- and Amplitude-Based Encryption," Appl. Opt. 39, 4117-4130 (2000)