Defect detection performance limit evaluation method of CT detection system

Abstract

The invention relates to a defect detection performance limit evaluation method of a CT detection system, and the method comprises the steps: carrying out the circumferential rotation with the centralposition of a one-dimensional point diffusion function of a CT image vertical interface of a comparison test block as a circle center, and obtaining a two-dimensional point diffusion function; carrying out convolution through the ideal defect gray level distribution two-dimensional image and a two-dimensional point spread function to obtain an ideal degradation defect gray level distribution two-dimensional image; obtaining a theoretical noise-containing defect gray level distribution function, finding a valley value between the defect and the gray level peak value of the material, calculating the ratio of the valley value to the gray level value corresponding to the defect peak value, and when it is judged that the gray level value is smaller than N according to the Rayleigh criterion,the defect can be detected; establishing a relation curve of the ratio of the diameter of the defect to the gray value in the CT image of the detected workpiece; and extracting a corresponding defectdiameter when the ratio of the median gray value is N, wherein the defect diameter is the theoretical defect detection limit of the detected workpiece. The evaluation method is more reliable and efficient, and is high in automation degree, low in detection cost and high in detection precision.

Description

technical field [0001] The invention relates to the field of CT detection, in particular to a defect detection performance limit evaluation method of a CT detection system. Background technique [0002] Industrial CT inspection technology is a practical nondestructive inspection method developed on the basis of X-ray inspection technology. It has the advantages of intuitive imaging, accurate quantification, positioning and qualitative, and can be archived and reviewed. It is widely used in industrial nondestructive testing, medical and health and other fields. At present, the detection capability of conventional CT equipment has reached the submillimeter level, and some special industrial CT detection equipment can even reach the micro (nano) level. However, due to different detection objects and technical requirements, the structure, configuration and performance of different CT systems may vary greatly. Commercially available equipment generally has problems such as high d...

AI Technical Summary

Problems solved by technology

Among them, the direct test method has high requirements on the accuracy of the test phantom, the phantom is difficult to process, the cost is high, and there is a mechanical processing limit. rate motif; the indirect theoretical calculation method has problems such as the abstraction of the test results given

Whether it is spatial resolution or density resolution test results, they only represent one-sided performance indicators of the equipment, and cannot give practical parameters directly related to defect detection performance.

This brings a lot of inconvenience to the quality control in the process of equipment performance parameter determination, equipment acceptance and identification and testing, and directly affects the reliability of industrial CT quantitative testing results.

The primary purpose of CT detection technology is the effective detection of internal defects, but the structural differences of the detection objects cause differences in detection performance. Therefore, it is important to implement a low-cost, efficient and accurate defect detection performance limit evaluation method for CT detection systems. Practical significance

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