对接管焊缝的双壁双投影工业X射线图像处理研究  

Image Processing Research on Double-walled Double-imaging Industrial X-ray Radiographs of Butt Weld

作　　者：刘奇[1] 李昌聪 黄韫栀[1] 王建 赖传理 张劲[1] 何凌[1] 殷鹰[3] 

机构地区：[1]四川大学电气信息学院,四川成都610065 [2]东方电气集团东方锅炉股份有限公司,四川自贡643000 [3]四川大学制造科学与工程学院,四川成都610065

出　　处：《四川大学学报（工程科学版）》2015年第2期89-94,共6页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家自然科学基金资助项目(51205265)

摘　　要：准确提取对接管焊缝的有效评定区域是实现自动识别X射线焊缝图像缺陷的首要步骤。针对这一难题,提出一系列结合X射线成像机理和焊缝灰度特征的图像处理方法。首先,以X射线成像原理为基础,对焊缝图像进行灰度变换;然后,以区域图像灰度方差为基础,修正焊道的偏移;进而利用最小二乘法拟合环形管焊缝,确定其中心;最后,利用距离映射方法将环形焊缝变换成矩形焊缝。根据3 000样本的测试结果,该算法对于焊缝中心点的确定以及椭圆拟合的成功率为100%,焊缝偏转角度修正误差为-0.216°±0.826°。因此,该设计能可靠地提取出低对比度X射线数字图像中的焊缝有效评定区域。The primary work to recognize butt weld defects automatically with X-ray radiographs is to achieve effective assessment area accurately. A specific image processing design was proposed to overcome extracting difficulties by combining X-ray imaging mechanism and weld gray features. Firstly,it conducts gray-scale transformation of the butt weld image based on X-ray imaging fundaments. Secondly,it corrects the offset of weld bead based on the regional gray variance. Thirdly,it adopts Least-squares method to fit the weld seam and determine its center. Lastly,it converts weld seam from annular to rectangular using the distance map. The results of 3 000 samples showed that the design can detect the center of weld seam and fit it with 100% success rate. The fitting ellipses showed that the weld seam deflection angle error is- 0. 216° ± 0. 826°. Therefore,it is feasible to extract the effective weld seam area from low contrast digital X-ray image for future assessment.

关 键 词：对接管焊缝 X射线图像 灰度特征 图像处理 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]