对钎焊焊缝的检测结果评定时，往往都要对缺陷的面积进行分析，标准中通常都规定了允许的缺陷最大面积，并限定缺陷占全部焊缝的面积比。目前超声波C扫描对于钎焊焊缝的检查已经可以实现了，但缺陷面积的计算还没有很好的解决方法。通过对C扫描图像特点的分析，提出了具体的解决方案，并进行了多种不同阈值选取方法分割图形计算结果的对比，供实际检测时参考使用。

The area of defects in brazing weld needs to be analyzed while evaluating the result of ultrasonic inspection. The current criteria standards normally specify the maximum allowable defects and define the allowable ratio of the area of defects to that of entire weld. Now it is feasible to inspect brazing weld by C-scan technology of ultrasonic inspection. However, there is no satisfied method to calculate the area of defects. Based on the analysis of the feature of C-scan image, this article mainly proposes the detailed solutions and compares several different methods to select threshold value, segment C-scan image and calculate the area of defects.