US Patent 7777897 Veneer roughness detection

A sample surface such as a surface of a wood veneer sheet is illuminated by a dual color light system and electronically scanned with a color line scan camera. The light system provides red and green light fluxes that are incident to a veneer surface from different directions, and corresponding line images associated with the red and green light fluxes are processed by rescaling, linear to log conversion, edge filtering, and/or thresholding to provide binary surface maps associated with veneer surface roughness.