初至拾取预处理

初至波常常会受到很多干扰因素的影响，因而无法保证准确拾取。小波变换的时频局部化分析方法能将频率与时间很好对应，对信号突变敏感，可以用来对资料进行初至拾取前的预处理。分析了影响初至拾取准确度的因素，探讨了选择小波函数和变换尺度的原则，并进行了不同小波变换处理效果对比。模型和实际资料处理结果表明，小波变换可以很好地恢复初至波的峰值，突出起跳位置。

Preprocessing of picking first arrival in complex situation

In seismic data processing of the northwest area in China, statics is the most effective method,and this method is based on picking first arrival accurately. In complex situation, first arrival always be distorted, and sometimes be covered by various noise. It makes the picking work difficult by automatic way, sometimes even by handwork. This paper discusses the factors, which influence the accuracy of picking first arrival, and presents a preprocessing method. If select accurately the wavelet function and the transform scale, we can primal recover the first arrival and can stand out the break point time, it will make automatic pick easier and more accurate.