Probability density function estimation of a temperature field obtained by pulsed radiometric defectoscopy

This paper presents testing of subsurface defects by Pulsed Radiometric Defectoscopy (PRD) techniques. Such techniques rely on transient infrared radiation from the sample heated by the short duration flux initiated by flesh. Response function is derivated by experimental measurement with infrared camera FLIR SC 620. Experimental results are considered for the samples with controlled designed defects. For illustration, PRD techniques analysis was applied to detect subsurface defects in the aluminum samples. The time history of the surface temperature after the absorption of a short light pulse is used to obtain information about the subsurface structure and the thermophysical properties of the material. For the obtained values of the temperature difference (measurand), which is the random quantity, it is necessary to determine the probability density function (PDF). Namely, PDF estimation of the temperature difference has been done using a Monte Carlo method and a modified least-squares method. Knowledge of the PDF for the output quantity is needed to determine a coverage interval.