Guided wave temperature compensation with the scale-invariant correlation coefficient

One of the greatest challenges toward developing guided wave structural health monitoring technology is the necessity to distinguish benign effects from those caused by damage. Variations in temperature, one of the most prominent benign effects, are known to stretch or scale ultrasonic signals in time. Several techniques have been proposed to compensate for the effects of temperature, but they tend to be computationally expensive, require locally convex conditions, or lack robustness to modeling error. In this paper, we present a new technique, based on the Mellin and scale transforms, which takes advantage of available fast algorithms for computing and compensating stretch-based operations. Using experimental data, we show our technique to be accurate, robust, and algorithmically faster than other existing techniques.