ROENTGENTOMOGRAFISKT FOERFARANDE FOER OBSERVERING AV FEL OCH KVISTAR I TRAE.

摘要

The invention concerns a method developed for tomographic 3-dimensional x-ray imaging of a log. Investigations performed indicate that water content and wood density variations along the longitudinal axis of the log, which are disturbing factors in imaging, can be considered constant over a short length of the log if the contour of the log is measured and the sequential images of the log are radially expanded or contracted according to contour variations. When the log has a defect such as worm or knot, the latter being the most important item of determination, said defect can be identified by subtracting the scaled image of a defect-free log section from the measured image. The measurement of the log contour at the imaged cross-section can be implemented in multiple ways presented in the invention. Said tomographically sliced images of the log are used for the reconstruction of a 3-dimensional image of the log to be utilized along the use of the log for different purposes.