Patent ID: 6029522
Filing Date: 2000-02-29
Classification: G01N

Abstract:
An apparatus for detecting localized anomalies in wooden members comprising:at least one pair of opposed ultrasonic transducers positionable across an axis about wooden members to be qualified;driving circuitry for driving a first ultrasonic transducer so as to produce an ultrasonic wave of known characteristics to produce an ultrasonic beam having a beam width in the wooden member wherein the beam width is greater than the width of the localized anomaly;detection circuitry connected to a second ultrasonic transducer receiving the ultrasonic wave after passage through the wooden members along multiple paths within the beam width, first paths passing only through the localized anomaly and second paths not passing through the localized anomaly whereby the ultrasonic waves along the first and second paths interfere with each other to practice an interference ultrasonic wave;an electronic computer communicating with the driving and detection circuits and executing a stored program to:(a) compare the interference ultrasonic wave against a standard to detect a distortion of the interference ultrasonic wave caused by an interference between portions of the ultrasonic wave passing along the first and second paths; and(b) provide an output indicating the presence of localized anomalies based on the comparison.