EDGE ENHANCEMENT TECHNIQUES FOR IMPROVING THE PERFORMANCE OF BINARY PHASE-ONLY FILTER PATTERN-RECOGNITION DEVICES

Several edge enhancement techniques are examined for improving the per formance of binary phase-only filter pattern recognition devices. Thes e include the linear techniques of blocking the lower Fourier orders a nd Laplacian filtering as well as the nonlinear techniques of phase ex traction and phase binarization. The results indicate that the nonline ar techniques outperform the linear techniques when there is no distor tion caused by aperturing the input information. However, when the inp ut is apertured, both the linear and nonlinear techniques yield approx imately the same peak-to-noise ratio.