Characterizing surface of wood laminates by out-of-plane polarimetric light-scattering measurement

The out-of-plane polarimetric imaging based on hemispherical light-scattering measurement for the wood laminates is presented. We constructed a goniometric polarized imaging system that is capable of capturing polarized light-scattering images. The backscattering of the wood surfaces is estimated with the use of out-of-plane laser illumination at three wavelengths (405 nm, 532 nm, and 671 nm). The intensity distributions of polarized light scattered from the wood laminates are measured. The polarized light-scattering images are generated for each detecting direction and found to be capable of inspecting anisotropy of the wood surfaces including the year ring. The measurements yield angular dependence of bidirectional ellipsometric parameters for distinguishing wood textures. The experimental results help in the study of bidirectional ellipsometric parameters to scheme a new polarized imaging system and to classify the wood grain orientation.