Nonlinear optical processing with halftones: Accurate predictions for degradation and compensation

Abstract

A general analysis of the halftone process for nonlinear transformations in optical signal processing is presented. The analysis considers the effects of the nonideal characteristics of the recording medium. The results predict output errors due to different parts of the recording medium characteristic curve for any nonlinear transformation. A synthesis method for a discrete halftone screen density profile is also described. This produces an optimum halftone screen density profile for any form of recording medium characteristic curve and any type of nonlinearity in the sense that it minimizes the mean-square difference between desired and degraded outputs. The results of a computer simulation for logarithmic and level slice functions are given. © 1987, Optical Society of America.