基于最大熵谱估计的超声检测回波频谱分析

Spectral Analysis on Echoes of Ultrasonic Detecti on Basedon the Maximum Entropy Spectrum Estimation

最大熵谱与传统FFT谱比较具有谱线平滑、分辨率高等优点.论述了最大熵谱估计的原理、方法及其在复合材料粘接质量超声检测中的应用.研究中采用最大熵谱法对回波信号进行频谱估计,确定回波中心频率,进而利用谱移法根据中心频率变化幅度判断界面的粘接质量.实验结果表明将最大熵谱估计用于复合材料粘接质量超声检测回波的处理中,更有利于缺陷特征的提取及检测水平的提高.

Comparing with traditional FFT spectrum the maximum entropy spectrum has the virtue of smooth spectrum line, high resolution and so on. The theory, method and application in ultrasonic detection on bonding interface of composite material of the maximum entropy are discussed. The maximum entropy spectrum estimation method is used to analyze the spectrum of echoes ,and then the center frequency of echo determined according to the variation of is calculated. At last the quality of bonding interface is center frequency based on spectral shift method. Experiment results show that it favors the extraction of defect characteristic and the increasing of detection level ,which the maximum entropy spectrum estimation method is applied in echo analysis of ultrasonic detection on bonding interface of composite material.