Combining X-ray and three-dimensional scanning of sawlogs— Comparison between one and two X-ray directions

In many sawmills, presorting of sawlogs is based on data from optical three-dimensional (3D) scanners. The use of X-ray log scanners is also becoming increasingly common and most sawmills installing an X-ray scanner already have a 3D scanner present. It is in this paper demonstrated how data from one and two-directional X-ray scanners can be combined with 3D scanner data using path length compensation. Examples show how the resulting images may be processed in order to predict quality parameters such as heartwood diameter and green heartwood density. Using the proposed method, it is possible to improve the accuracy of these important quality sorting parameters using existing equipment. This will improve the presorting at sawmills, thus reducing the production of off-grade products carrying unwanted combinations of dimension and grade.