METHOD AND APPARATUS FOR ANALYZING A WEB OF MATERIAL

摘要

A high-intensity light source passes a narrow beam of light through the entire width of the moving paper web. Variations of received light intensity are determined by a linear array OCD camera on a pixel-by-pixel basis across the width of the web. The predetermined value of received light intensity is assigned according to the location of the group of pixels. The signals are normalized to account for variations in sheet colouring and intensity of the light source. An average light intensity is determined for predetermined locations across the web.