摘要 |
<p>The invention is concerned with measuring "on-line" the surface roughness of a moving sheet material, e.g. a paper web. The method comprises illuminating the moving web, preferably at a low angle, suitably collecting the light reflected from the moving web and processing the light by means of a sensitive photo-electrical system. The electrical signals thus obtained are divided into an AC and a DC component, the components are separately measured and their ratio used as an index of roughness. An apparatus for carrying out roughness measurements on a moving paper web, e.g. on a paper machine, is described.</p> |