A unified model of inspection and monitoring quality

Non-destructive evaluation (NDE) through inspection and monitoring is an integral part of asset integrity management. The relationship between the condition of interest and the quantity measured by NDE is described with probabilistic models such as PoD or ROC curves. These models are used to assess the quality of the information provided by NDE systems, which is affected by factors such as the experience of the inspector, environmental conditions, ease of access, or imprecision in the measuring device. In this paper, we show how the different probabilistic models of NDE are connected within a unifying framework. Using this framework, we derive insights into how these models should be learned, calibrated, and applied. We investigate how the choice of the model can affect the maintenance decisions taken on the basis of NDE results. In addition, we analyze the impact of experimental design on the performance of a given NDE system in a decision-making context.