Abstract
The Prewitt, Sobel, and Roberts difference operators are presently implemented by means of a symbolic substitution-based optical computing architecture in the interest of two-dimensional image-sharpening applications. Roberts operators are noted to require four reduced minterms, rendering their implementation comparatively easy; since each reduced minterm of the Roberts operators is composed of only four pixels, the corresponding holographic memory has the most optimum page density. It is found that the Roberts operator-based symbolic substitution scheme is the most hardware-efficient, while yielding thinner image edges. (O.C.)