Computer aided imaging detection:Computed Radiographic Testing,Referred to as Cr, computer-aided imaging technology is also known as photo stimulated storage phosphor (PSP) imaging, which is an advanced digital X-ray imaging technology. CR's photography mode is similar to the screen film system of traditional cassettes, only a special medium is used to replace the traditional film, and this special medium is enclosed in a dark box, which is called imaging plate (IP). IP is the core component of CR equipment to form images. IP can be divided into flexible plate and rigid plate according to whether they are bent or not. The former uses elastic fluorescent coating, which can be bent at will, has simple structure, fast scanning speed and small equipment volume; the latter can not be bent, has small damage probability and causes less artifacts. According to IP, it can be reused, with high temperature resistance, large tolerance, no need to wash film on site and no need to use in dark environment. At present, it is widely used in service maintenance in industry. Cr is also commonly used in the detection of steel castings. For small cracks, internal pores, slag, shrinkage and other defects, the detection contrast is very high, and the small defects can be measured.