Analysis of wood surface waviness with a two-image photometric stereo method

This paper describes a two-image photometric stereo (PS) method for analysis of surface waviness on planed wood products. This method is based on an assumption that the wood surface is a Lambertian surface. In addition, owing to the fact that surface waviness on planed wood is mainly composed of cutter marks, which fluctuate only in one dimension, three-dimensional surface topography can reasonably be represented by a two-dimensional surface profile. Accordingly, a surface waviness profile can be extracted from two images of the surface under specifically arranged illumination. Measurement results from the two-image PS method are compared with those from a laser profilometer. Comparison indicates a high correlation between the two methods.