Objective Image Quality Assessment in infrared non-destructive testing

Diverse image processing techniques are used in Thermography for Nondestructive Testing (TNDT) to enhance images contrast and visibility of cracks or defects in materials. A common procedure to compare the ability of these image processing techniques is subjective. Experts visually compare the outcomes of the techniques and determines which technique, for some given parameters, works better by counting the number of defects made visible in a particular image. The results of these comparisons become arguments to explain why a new technique is more convenient than previous techniques. SNR (Signal to Noise Ratio) is a quantitative measure of defect´s visibility. However, this is local and variable over time. In this paper we proposed Image Quality Assessment (IQA) based metrics to measure the contrast enhancement obtained after using image processing techniques in TNDT.