Modeling of Internal Defects in Logs for value Optimization based on Industrial CT Scanning

For spruce (Picea abies (L.) Karst.), as with most other species, the value of a log is to great extent determined by its defects. That is the reason why sawyers, aiming at the optimal utilization of a log, were naturally interested in defects, their number, position and shape. X-ray computer tomography (CT) scanning is able to detect internal density variations related to defects. In order to use this information for optimizing a computer based sawing process, it is necessary to model different defects by geometric descriptions which are easy to handle. This study describes how to detect and model internal wood defects like pith, cracks, knots and resin pockets in spruce logs from non-destructive measurements using industrial CT and automatic image analysis processes. The proposed methods and models are experimentally evaluated by destructive measurements.