一种X射线测厚校正方法的研究

Research of a Correction Method of Thickness Measurement Based on X-ray

针对工业CT系统中所使用的X射线是一种多能谱射线,进而导致厚度测量不准确的现象,介绍了X射线测厚原理,分析了X射线在对物体进行厚度测量时发生射束硬化现象对测量结果的影响,推导出一种用于测厚的校正数学模型,并通过CD-300BXR型工业CT研究平台对该数学模型进行了验证。实验结果表明,当被测钢板厚度范围为5～50 mm时,利用该校正模型进行测厚的相对误差在±0.5%以内,能满足实际测厚需求。

The X-ray that used in industrial CT is a multi- energy ray, which leads to inaccurate thickness measurement. Considering this, the principle of X - ray thickness measurement and the effect of beam harden- ing phenomenon of X - ray are analyzed in the paper. Then, a mathematical model for correction is derived, and we verify the model through CD - 300 BXR research platform. The experimental results show that, the rel- ative error of thickness measurement based on the proposed model is less than 0.5 % when the measured steel plates range from 5 mm to 50 mm, which can satisfy the actual demand for thickness measurement.