针对计算机射线照相技术(Computed Radiography，CR)图像中焊缝区域以及缺陷的提取问题，运用小波模极大值法提取缺陷。文章以铝焊缝CR图的缺陷提取为例，首先使用小波模极大值法处理，通过增强的列灰度曲线可明确地获得焊缝边界以及缺陷所在的局部位置，然后根据尖峰宽度的中值大小大致评估区域内缺陷是裂纹类还是非裂纹类缺陷，同时比对几种缺陷提取方法。试验表明，小波模极大值法较其它方法能更准确地提取焊缝边界及焊接缺陷，具有良好的可行性与实用性。

This paper reported the way of defect extracting by wavelet modulus maxima method for welding area of computed radiography(CR) image, for which the defect extraction of aluminum welding CR image was taken as an example. Firstly, we used wavelet modulus maxima method to obtain enhanced grey curve of Al welding CR image which could show a clear boundary and local position for weld defect. Sequentially, we classified defect in welding zone as crack defect or non-crack defect by peak width, and compared it with other defect extraction methods. The results indicated that wavelet modulus maxima algorithm was feasible and practical, which improved the recognition accuracy of welding zone and defects extraction in computed radiography image based on wavelet transform modulus maxima.