基于工业CT成像的弹药小底隙测量方法研究

Study on Measurement Method for Small Bottom Gap of Ammunition by Industrial CT Imaging

在弹药产品的质量无损检测中,小底隙的精确测量是保证产品质量的重要技术之一。为精确测量小底隙,利用CT成像的体积效应,提出一种小底隙厚度测量方法。在设定的扫描层厚下对产品进行工业CT断层扫描,使底隙完全包含在扫描层厚范围内;再将工业CT断层图像上的灰度差异转换为等效密度差异;并利用产品的材料密度及底隙物质（空气）密度来计算小底隙的厚度。实验结果表明,该方法可对0.3-2.0 mm的底隙进行测量,其最大绝对测量误差为0.03 mm,最大相对测量误差为4.8%.该方法解决了小底隙精确测量的技术难题,可满足产品无损质量检测和评价的需要。

In the non-destructive testing for some ammunition, the precise measurement for small bot- tom gap is one of the main techniques to ensure their quality. A measurement method for thickness of the small bottom gap was proposed by volume effect of the CT imaging dexterously. The position where a gap exists was scanned by industrial CT at a set scanning thickness, in which the gap is con- tained in the scanning range; the gray difference was transferred into density difference by the CT image; the thickness of the gap was calculated by densities of the material and the air in the gap. The measured result shows that the method can be applied to the gap with thickness from 0.3 mm to 2.0 ram, the maximal absolute error is less than 0. 030 mm and the relative error is less than 4.8 %. The proposed method solves the problem of measurement for the gap, and satisfies the requirement of non- destructive testing and evaluating for products.