钎着率是判断电触头钎焊质量的重要指标.提出了一种基于超声C扫描图象的钎着率计算方法,从而实现了电触头钎焊质量的自动评价.首先使用基于相依矩阵的平均对比度度量自动选取阈值,并用其对电触头钎焊界面超声C扫描图象实施阈值分割,然后计算针着率,并按照缺陷的回波高度特征对缺陷进行分类,最后,给出了实验结果. Brazing rate is an important index for judging the quality of brazing of electrical contact.A method of calculating the brazing rate based on ultrasonic C-scan image is proposed to realize the automatic evaluation of brazing quality of electrical contact.Firstly, The average contrast measure automatically selects the threshold value, and uses it to make the threshold segmentation on the C-scan image of the electrical contact brazing interface, then calculates the pinning rate, and classifies the defects according to the echogenicity of the defect. Finally, Experimental results.