【摘要】 针对粗晶材料超声检测时严重的结构噪声使信噪比很低的问题,使用非线性时频分布对超声信号进行处理,充分考虑信号的时域、频域和相位的信息,根据超声信号在缺陷和噪声处瞬时频率的不同,结合超声信号的空间投影特点,提出了一种基于信号瞬时频率的超声信号处理方法。首先使用Choi-Willianms分布将信号变换到时频域,估计出信号瞬时频率,然后通过瞬时频率的有序度对超声信号进行加权处理。该算法充分利用了超声信号时域、频域和相位的信息,不仅消噪性能好,而且缺陷定位准确。更多还原

【Abstract】 Considering the differences between the flaw signals and the noise signals, we proposed an ultrasonic signal process method based on instantaneous frequency and the ultrasonic signal’s spatial distribution. First we put the ultrasonic signal into the time-frequency domain by means of Choi-Willianms Distribution(CWD). Then we can estimate the signal instantaneous frequency using the peak of the CWD. So, we can weightily process the ultrasonic signals depending on the degree of the instantaneous order. This method made full use of the time domain,the frequency domain and the phase information of the ultrasonic signals. It can effectively stand out the signals of the flaw and restrain the noise.更多还原