ドット形状の階調再現特性への影響

抄録

A computer simulation method is proposed to predict halftone reproduction properties, taking account of the effect of light scattering in paper, halftone dot shape and screen period on tonal appearance by using computer image processing technique. The simulation method is based on the principle of the analytical calculation method suggested by Ruckdeshel et al. The gray scales modulated by same dot patterns as the computer simulation by using a laser printer are generated to study experimentaly the relation between the optical dot gain and the halftone dot shape. The simulation data are compared with experimental data. 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 function of paper. The correlation between the dot gain and the perimeter is very strong and the change of the optical dot gain is predicted by measuring the perimeter to some extent when the point spread is very smaller than the screen ruling period. The correlation become weaker as the point spread become wider than the half size of the ruling period.