背景消除是焊缝X射线自动检测中缺陷分割的常用方法，其核心是焊缝背景图像的获取。由于焊缝的多样性，常用的低通滤波和曲线拟合方法所得到的背景不够准确，造成较多误检率。研究了基于局部曲面重构的背景消除法，先对焊缝列灰度进行分析，获取潜在的缺陷区域，再对该区域进行曲面重构，获得焊缝背景图像。试验表明，该方法可有效减少误检和漏检，并获得良好的焊缝缺陷形貌。

Background subtraction is often adopted in automatic weld defects inspection techniques based on real-time X-ray images. The key to this method is estimating of weld background, and it is mainly realized by low-pass filter or curve fitting methods. Generally, there are many false alarms and inaccurate defect shape due to inaccuracy of weld background obtained by these methods. In this paper a new background subtraction based on partial surface reconstruction was proposed. Firstly, the possible defect positions were identified by gray-level wave analysis, and then weld background was estimated by reconstruction in these areas. Results showed that false alarm and missed detection had been decreased effectively, and the defect shape had been more accurate.