中文摘要：

针对金属基复合材料结构中，各层的超声检测回波会严重混叠，难以分辨甚至会丢失深层的缺陷信息的问题，提出了使用db3小波为基函数来进行小波变换和特征提取，结果显示，提取出的特征可有效地进行各层粘接缺陷的检测。实验结果表明，提出的特征提取方法可用在粘接结构的无损检测中。

英文摘要：

This paper presented a wavelet-based approach for extracting feature from ultrasonic non-destructive evaluation data of a test Metal Matrix Composite Structure （MMCS） specimen. These features were then used to obtain an estimate of the specimen＇s bonded properties. When the MMCS underwent ultrasonic non-destructive evaluation, echo from interior layers often overlapped severely, causing information from individual layers to be obscured or lost completely. A complex- valued mother wavelet based on the impulse response of the test instrumentation system, was used to perform the wavelet transform and separate the overlapping echoes. The extracted features displayed are effective to analyze and identify the bonded properties. It is believed that the features extracted via the method outlined provides considerable promise in the area of the test of multi-layered bonded structure.