Probability of Detection for Fatigue Crack in Pulsed Eddy Current Thermography

In pulsed eddy current thermography (PECT), probability of detection (POD) is one of the most important indexes to evaluate the reliability of detection. Generally, POD is defined as the probability that a crack with particular length is detected under special test condition. In this paper, a series of metal plates with different lengths of fatigue cracks were introduced to obtain the thermal response through the orthogonal experiment. A linear regression model was established to describe the relationship between thermal responses and crack lengths, and the maximum likelihood estimation (MLE) method was employed to achieve the specific parameters of POD model. Then, the resulting confidence interval of POD was presented based on Wald method. The research aims to provide a quantitative evaluation method for detection reliability in PECT.