Ultrasonic detection of knots and annual ring orientation in Pinus radiata lumber.

摘要

An ultrasonic defect detection system for radiata pine (Pinus radiata) lumber based on 0.5 Mhz sound transmission through wood was tested. The feasibility of detecting knots, grain deviation, and growth ring angle with this system was investigated as well. The knot material, area of knot influence, and growth ring angle were significantly correlated to wave velocity. The ultrasonic scanning showed good agreement with visual prediction.