基于改进Morlet小波的超声回波信号处理

Research on ultrasonic signal processing based on improved Morlet wavelet for felted composite

粘结复合材料的超声回波检测信号夹杂了大量的噪声,完全淹没了有用的裂纹缺陷信息,基于时域或频域的分析方法难以判断其是否存在缺陷。在对信号作多尺度分析的基础上,改进了Morlet小波,并基于改进Morlet小波对信号进行了各种分析。当取多个尺度参数时,基于改进Morlet小波变换得到的小波系数都包含有缺陷信号的频率成分,这样便解决了多分辨率分析时多尺度小波系数在分析窄频带缺陷信号时的不足。

The ultrasonic echo detection signal of felted composite is mixed with a mass of noise which submerges the use- ful flaw signal completely. It is difficult for the time-domain or frequency-domain method to determine whether the product is eligible. Through the multi-scale analysis of signal, improved Morlet wavelet is obtained, and based on improved Morlet wavelet the ultrasonic signal is analyzed. When more than one scale parameter is applied to the continuous wavelet transform based on the improved Morlet wavelet, the wavelet transform coefficient includes frequency components of defect signal. And in this way the defects of the multi-scale wavelet coefficient in the application of narrowband signal analysis are overcome.