A Surface Quality Evaluation Method for Establishing Image-Surface Causal Chain in X-ray Computed Tomography Measurement

Ensuring reliable measurement quality in X-ray computed tomography (XCT) dimensional metrology remains challenging, because the complete causal chain—from XCT influencing factors, through image quality, to final surface quality—has not yet been established. A key gap is the absence of a surface quality evaluation method with metrics directly linked to image quality metrics. This paper addresses that gap by introducing such a method which determines the metrological structural resolution (MSR), a critical resolution metric for XCT dimensional metrology. The method computes the two-dimensional surface amplitude transfer function (SATF) to evaluate XCT systematic and random errors and also to identify the measurable scale limit. The MSR can then be determined by either the permissible systematic error or the measurable scale limit. By providing metrics that map surface systematic error, random error and MSR onto image blur, noise and resolution, the proposed method effectively completes the XCT causal chain and enhances the understanding of how XCT influencing factors affect measurement quality.