数字超声无损评价系统中的脉冲噪声

Noise Analysis of Digital Ultrasonic System and Elimination of Pulse Noise

在用数字超声系统进行焊接接头评价时发现， 噪声是微弱超声信号检测的主要障碍。建立数字超声系统的物理模型， 分析声学噪声和非声学噪声， 提出消除脉冲噪声的极值滤波算法。实验证明， 该算法简单高效，能有效地去除脉冲噪声， 且保持信号的有用分量不受滤波影响。

In the evaluation of welded joint using digital ultrasonic system, it is found that it is noise that constitutes the main difficulty in the detection of weak ultrasonic signal. In this work a physical model on digital ultrasonic system is established and applied to analyze noises encountered in ultrasonic testing. An algorithm of extremum filter is constructed to suppress the pulse noise. Experiment verifies that the algorithm is simple and efficient, which can not only eliminate the pulse noise substantially but also retain the other components of the signal unchangeable.