一种新型超声信号消噪技术及其DSP实现

A New Denoising Technique for Ultrasonic Signals and its DSP Implementation

为了提高超声无损检测和无损评价中基础数据的信噪比,利用小波变换多分辨率性能实现对超声信号的消噪。将原始超声回波信号进行小波域子带分解后,按照一定的规则对细节信号进行软阈值处理,然后根据概貌信号和处理后的细节信号重构原信号,从而消除了噪声,达到提高信噪比的目的。该方法在DSP上进行了实现,实验结果表明,该方法增强了消噪性能的稳定性,提高了超声回波信号的信噪比。

In order to enhance the Signal to Noise Ratio （SNR） of fundamental ultrasonic echo signals for Ultrasonic Non-Destructive Testing （UNDT） and Ultrasonic Nondestructive Evaluation （UNDE）, wavelet transform multi-resolution ability was used to denoise ultrasonic signals. After ultrasonic echo signals were decomposed into sub-bands in wavelet domain, the detail signals were processed according to a certain rule. Then the target signals were reconstructed using appearance signals and processed detail signals to reconstruct the original signal for enhancing its SNR by removing noises. This method was implemented in DSP. The experimental results indicate that the presented technique has high reliability of denoising performance. Besides, the SNR enhancing ability for ultrasonic target echo signals contaminated by noises is also improved.