A Multi-Scale Contrast Enhancement Method for DR Image of Nuclear Power Weld

Digital radiography (DR) is the latest X-ray inspection method in nuclear power welds. Aiming at the problems of poor contrast of nuclear power welding seam DR images and easy missing of details, a multi-scale contrast enhancement algorithm for 16 bit DR image is proposed. First, laplacian pyramid is employed for decomposing 16 bit DR image, and then gaussian smoothing filter and subtraction algorithm are used to extract the image detail, and a s-type mapping function is used to enhance detail, and finally the enhanced detail is added to approximate image for DR image reconstruction. The multi-scale contrast enhancement experiments are performed on DR images containing linear defects or circular defects. When the parameters L = 10 and p = 0.8, the developed algorithm can effectively enhance the detail contrast and improve the ability of detect recognition. The developed algorithm has good prospects of engineering application.