I. Introduction
The value of hardwood lumber is determined by the quantity, size, and types of internal log defects such as knots, cracks, decay, and other anomalies of tree growth that eventually appear on the lumber surfaces. Depending on the nature of the end utilization, each log is sawed to minimize the presence of these internal defects on the resulting lumber surfaces. In order to achieve this goal, the internal defects within the log must be accurately identified and localized prior to the sawing of the log. The knowledge of the nature and positions of the internal log defects must then be exploited to determine a lumber production strategy that maximizes the value and yield of the resulting lumber product(s). In most sawmills, however, logs are processed into lumber based solely on external log inspection and knowledge of lumber grades with little or no information about the internal log defects and with inaccurate or incomplete geometric log data. This adversely affects the accuracy of the lumber processing, resulting in suboptimal lumber production where the potential value of logs is wasted.