Computer Simulation for Tone Reproduction Properties of Dot with Microscopic Edge Shape Fluctuations

Abstract

The effects of the dot feature with edge shape fluctuation on tonal appearance are studied by using computer generated dot pattern and computer simulation technique based on image processing. The unperturbed chain and square dots which are used in conventional reproduction process are formed for simulation. The various types of fluctuations on edge shape are generated from composition of harmonic waves having random initial phase and added to unperturbed dot. It has been shown from this study that the optical dot gain is closely correlated with the perimeter of the dot pattern and the width of optical point spread caused by light diffusion effect in substratum. The correlation between dot gain and the perimeter is very strong when the point spread is very small. The correlation becomes weaker as the point spread becomes wider than the half size of dot separation and/or the spatial frequency components contained in edge fluctuation become higher.