Algorithmic Method for Decorrelating a Bottom Signal and Structural Noise during Thickness Gauging of Large Items using Ultrasonic Phased Arrays

Background/Objectives: The article discusses problems of isolating signals from the structural noise correlated with a sounding signal using the ultrasonic echo method of measuring the thickness of large items with complex structure. Methods: The article demonstrates that in addition to spatial decorrelation of the bottom signal and the interference correlated with it, it is possible to use algorithmic decorrelation by using phased arrays and the signal processing algorithm which searches for the reflecting planes. Findings: Preliminary spatial correlation of the “useful” signal from structural noise is a condition for signal isolation. Measurement of the thickness of large, complexly structured concrete items is used to demonstrate that the use of the “focusing on a plane” algorithm will improve the bottom signal/structural noise ratio and thus increase the measurable thickness of the concrete items. Applications/ Improvements: The use of the algorithm, "focusing on the plane" in modern thickness gauges and scanners applied for monitoring concrete structures can significantly increase the reliability and accuracy of defect detection.