采用EMD的管道泄漏声信号增强

Enhancement of leak signals using EMD in pipeline

在管道泄漏检测中,采集信号中的噪声会影响泄漏检测的准确性和泄漏定位误差。已有的管道泄漏去噪方法依赖经验参数的设置,去噪效果受管道条件和环境影响大。本文提出使用不依赖经验参数的EMD用于管道泄漏声信号增强。现有的EMD去噪方法需要知道有用信号或者噪声的特征,不适用于特征随管道工程条件及环境变化较大的泄漏信号的去噪增强。提出改进的EMD信号增强方法,该方法不需要知道泄漏信号和噪声特征就可以提取与泄漏信号相关的IMF。在改进的EMD信号增强方法的效果分析中,信噪比提高可达16 d B。在大量实际工程管道泄漏信号处理中,使用改进的EMD信号增强方法之后得到的时延峰值更明显,漏点定位精度更高。

In the pipeline leak detection,noises in collected signals influence the accuracy of leak detection and the leak location error. Existing denoising methods depending on empirical parameters are easily affected by the pipeline condition and environment. EMD（empirical mode decomposition） is an adaptive signal decomposition method,which is independent of empirical parameters,and it is proposed to increase the SNR of leak signals of pipeline. Existing EMD denoising methods need to know the characteristics of useful signal and noises. However,characteristics of leak signals and noises are difficult to be predicted in the unknown pipeline,and existing EMD denoising methods can＇t be applied to the enhancement of leak signals in pipeline leak detection. An improved EMD signal enhancement method is propsed,in which the relevant IMF（intrinsic mode function） that contains leak signals can be extracted without knowing characteristics of leak signals and noises. In simulation analysis,the improved EMD signal enhancement method can increase the SNR of leak signals about 16 d B. In the processing of numerous practical pipeline leak signals,the peak of adaptive time delay wave is more obvious,and the accuracy of leak location is improved.