The potential of Vis- and NIR-spectroscopy for the nondestructive evaluation of grain-angle in wood

摘要

Grain angle is of major importance for load-bearing applications of wood because it exerts a strong influence on strength and elasticity. This study proposes PLS (partial least squares) analysis of Vis and NIR reflectance spectra as a possible means for a rapid and nondestructive determination of grain angle. With a root mean square error of 6degrees, and a coefficient of determination of 0.77 (Vis) and 0.80 (NIR), both spectral ranges proved suitable for the measurement of grain angles up to 40degrees.