The inverse geometric problem applied to the IR-CAT method for the detection of an irregular subsurface cavity

Publisher Summary Use of infrared scanners (m-scanners) for the nondestructive detection of subsurface cavities, as proposed by Hsieh and his co-workers, is a steady-state thermal detection method. In this chapter, the inverse geometric heat conduction problem is solved in the IR-CAT method to detect an irregular subsurface cavity. An infrared scanner is used to non-intrusively retrieve the surface temperature distribution of a test sample, which encloses an irregular cavity. The cavity is heated using foil heaters, and the temperature at the cavity surface is measured using thermocouples. Cauchy thermal conditions are prescribed at the exposed surface. The BEM-based anchored grid pattern method is used to locate and determine the shape of the subsurface cavity. Infrared thermography techniques using infrared scanners, sample preparation, calibration curve, and temperature retrieval are discussed.