中文摘要：

声发射（AE）信号初至时刻精确拾取是声发射源定位中的关键问题,该文探讨基于连续小波变换的Holder指数方法拾取AE信号初至时刻,为突出信号初至时刻的奇异性特征,提出对信号包络估计的包络Holder指数方法。通过对模拟AE信号和金属裂纹AE信号应用结果表明：包络Holder指数可以精确提取AE信号的初至时刻,误差小于2μs,能为AE源定位提供一种有效手段。

英文摘要：

The identification of the first arrival time of acoustic emission （AE） signal is one of the key problems in AE source location. This paper presented a method of envelope Holder exponent to identify the first arrival time of AE signal. Firstly, the envelope by Hilbert transform was extracted to highlight the singularity character of signal. Then, HSlder exponents of the envelope signal were estimated and the curve based on these exponents showed the first arrival time distinctly. Applied the method to AE signals produced by pen lead and metal crack propagation, the first arrival time can be identified correctly. The identified error was less than 2 μs. The research results demonstrated that the proposed method can identified the first arrival time of AE signals precisely.