输油管道应力波检测中的小波去噪方法研究

本文介绍了一种适用于油田输油管道应力波检测的小波去噪方法。在盗油实时监测时，利用冲击激励产生的应力波到达两个检测传感器的波达时刻的差对冲击激励点进行定位。由于小波变换具有多尺度分析的优点，根据有用信号和噪声奇异性的不同及其在小波变换不同尺度下的传递特性的不同，区分信号和噪声，进行小波系数的阈值选取后，利用剩余的小波系数重建信号，得到有用信号的波形。试验发现，该法可以很好地去除噪声，从而使应力波的波达时刻的计算的准确度提高。

Wavelet De-noising Method in Stress Wave Detection for Oil Pipeline

A signal de-noising method using wavelet analysis in stress wave detection for oil pipeline is introduced in the paper.The position where stealing happened is derived by calculating the difference between the times at which the stress wave reaches the two adjacent detection transducers.Since the singularities and their propagation properties of desired signals and white noises are different,it is possible to distinguish the desired signals from noises in different decomposition scales,and the wavelet coefficients of the noises are discriminated according to thresholds for wavelet reconstruction,which results in de-noised signals.It is found that the noises are well cancelled,and the detection accuracy is promoted.