工业CT检测中小缺陷定量方法

工程应用中采用工业电子计算机断层扫描(computed tomography,CT)技术对金属材料内部缺陷进行检测,基于等值面分割法对缺陷进行尺寸测量,然而该方法存在小缺陷定量精度低、稳定性差等问题.对此提出了一种利用CT图像局部区域灰度变异系数表征小缺陷尺寸的方法.首先,设计制作不同穿透厚度、缺陷直径(通孔)的对比试...

A method for quantifying small defects in industrial CT detection

In engineering applications, industrial CT technology is usually used to detect small defects inside metal materials through isosurface segmentation. However, the small defect quantification method has problems such as low accuracy and poor stability. It uses differences in grayscale variation coefficients of small defect in CT images in order to characterize defect sizes for higher measurement accuracy. First, the comparative test block is designed to have different penetration thicknesses and defect diameters (through holes), and scan it to obtain CT images of small defects. Analyze the gray features of local images of small defects, establish a quantitative method of small defects based on local features, and compare with other measurement methods. The research results show that the correlation coefficient between the coefficient of variation and the area of small defect is stable above 0.99. The quantitative method based on the coefficient of variation is more accurate and stable than the FWHM method (isosurface segmentation method). This method is easy to operate, and has high practicability. It is one of the effective ways to detect small defects.