在对合成金刚石进行超声波探测的过程中，部分缺陷信号因噪声信号的混入而难以准确获取。本研究运用多分辨分析小波阈值的消噪方法，设计出带有改进效果的新函数并应用在金刚石缺陷信号处理领域。该函数方法可以减少硬阈值和软阈值函数各自的不足，例如在离散估计值和分解小波系数两者间存在的定值误差，具有表达式简单、计算方便等优点。通过实际缺陷噪声信号的测试表明：这种改进的阈值消噪函数与传统的硬、软阈值消噪函数相比较，可获得均方误差值减小和重构波形信噪比提高的优异消噪表现，能明显提高合成金刚石缺陷识别的准确率。本研究将超声波检测与小波变换技术相结合，并将其应用于合成金刚石的缺陷识别，对人造金刚石产业具有重要意义。%In the processing of ultrasonic detection of synthetic diamond,some defect signals are difficult to obtain accurately since they are mixed with noise•Based on multi-resolution analysis of wavelet de-noising threshold,a new function with improved results was designed and applied to process diamond defect signals•This threshold function reduced the disadvantage of hard-threshold function and soft threshold function,such as the fixed value error between the discrete estimated values to the decomposition wavelet coefficients•Simultaneously,this kind of function possessed several advantages, for instance,relative simple expressions and convenient calculation methods•Test results demonstrated that this modified threshold function was able to get less mean-squared error and improve the signal-to-noise ratio of reconstruction signals comparing with the methods of hard-threshold and soft-threshold•The modified threshold function was excellent de-noising advantages,which significantly improved the accuracy rate of synthetic diamond defect recognition•The combination of synthetic diamond ultrasonic detection and wavelet transform,as well as its application in processing of ultrasonic detection of synthetic diamond,played a significant role in synthetic diamond industry.
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