Measurement Algorithm for Image Structure Noise on Hardcopy

Abstract

Image structure noise sometimes is a key factor influencing the image quality of hardcopies and widely exists in presswork using halftone technology. This paper describes an algorithm for measuring image structure noise, including moiré and screen dot effect. In order to objectively meter the degree of structure noise, L* spectrum of colorful flat-area patch is mainly utilized to represent the structure noise of images, according to the subtraction principle and frequency prediction algorithm of moiré. With human evaluation and rating, a linear model of structure noise is regressed by moiré index and screen dot index. Finally the high correlation between human rating and metrics proves the effectiveness of the model.