STRENGTH GRADING AND PREDICTION OF SHAPE STABILITY BY USE OF OPTICAL AND LASER-BASED SCANNING TECHNIQUES

摘要

The paper assesses the potential of quality sorting of timber by use of modern scanning techniques, employing both fluorescent lighting and lighting from a large number of laser point sources. Tests were performed using wood-scanning equipment from one of its major manufactures. The results appear promising, especially in providing reasonably accurate predictions of grain-angle distributions on the wood surfaces, as well as rather accurate descriptions of knot locations and of fibre-angle disturbances around knots. A close characterization of end cross sections with respect to radial and tangential directions alike and of annual ring widths was also obtained. Characterization of the growth of annual rings in early to late wood was rather successful too. The techniques employed are illustrated by results of ongoing studies of both planed boards and of glued laminated beams.