Three dimensional fibre orientation models for wood based on laser scanning utilizing the tracheid effect

Recentresearch has shown that machine strength grading based on tracheid effectscanning of fibre directions projected on board surfaces can provide moreaccurate strength predictions than today’s grading methods. Scanning techniquesin which 3D fibre orientations can be taken into account would most likelyimprove the strength grading results even further. In this investigation thepossibility of determining such 3D orientations by dot laser scanning wasinvestigated. For a set of 20 side boards, scanning data was used to calculatetraversing knot directions which were in turn applied to determine pithlocation and root end of original logs. By means of the shape of laser dots,which due to the tracheid effect are turned elliptic on board surfaces, and thedetermined pith location, the size and direction of the diving angle of thefibres was calculated. The research showed that this angle can be accuratelydetermined in the vicinity of knots