An evaluation method of defect detection performance limit of CT inspection system

Abstract

The invention relates to a defect detection performance limit evaluation method of a CT detection system. The center position of the one-dimensional point spread function of the vertical interface of the CT image of the comparison test block is used as the center of the circle to rotate circumferentially to obtain the two-dimensional point spread function; The two-dimensional image of the ideal defect gray distribution is convolved with the two-dimensional point spread function to obtain the two-dimensional image of the ideal degraded defect gray distribution; and the theoretical noise-containing defect gray distribution function is obtained, and the defect is searched for between the gray peak of the defect and the material. Valley value, calculate the ratio of the gray value corresponding to the valley value and the peak value of the defect, according to the Rayleigh criterion, when the gray value is less than N, the defect can be detected; in the CT image of the inspected workpiece, the defect can be established The relationship curve of the ratio of diameter to gray value; extract the corresponding defect diameter when the ratio of medium gray value is N, and the defect diameter is the theoretical defect detection limit of the inspected workpiece. The evaluation method is more reliable, efficient, and has a high degree of automation, low detection cost and high detection accuracy.

Description

technical field [0001] The invention relates to the field of CT detection, in particular to a method for evaluating the limit of defect detection performance of a CT detection system. Background technique [0002] Industrial CT detection technology is a practical non-destructive detection method developed on X-ray detection technology. It has the advantages of intuitive imaging, accurate quantification, positioning and qualitative, and can be archived for review. At present, the detection capability of conventional CT equipment has reached the sub-millimeter 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. Commercial equipment generally has problems such as high cost of the device itself, high detection cost, low detection efficiency and complex factors affecting the dete...

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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