Paperipinnan laadun testaus

摘要

The invention relates to an apparatus for testing the surface quality of paper. The apparatus comprises: a light source (1) for generating a light beam (2), directing means (3) at least a part (4) of said generated beam substantially perpendicularly towards the surface of said paper (5), measuring means (7) for measuring the intensity of coherent backscattering (8) from the surface of said paper at different angles, and analyzing means (10) for analyzing the measured intensity at different angles in order to determine the surface quality of said paper.