Detection of Void to CFST with Infrared Thermal Enhancement Based on Contrast Limited Adaptive Histogram Equalization

Infrared images are often faced the problem of low resolution and low contrast ration, so the fusion of thermal signal reconstruction algorithm (TSR) and constrained limited adaptive histogram equalization (CLAHE) has been proposed to solve the problem.In this method, the temperature response curve of every pixel in the image is transformed from the time domain to the logarithmic domain.The reconstructed images are obtained by logarithmic domain's first and second derivative.Then, CLAHE is used to enhance the reconstructed images.Experimental results show that the algorithm can significantly enhance the contrast ration between defects and sound areas, realize the accurate positioning of defects, and depicted the actual shape of defects more accurately.Meanwhile, the positioning of defects can be detected in advance, so as to shorten the heating time.