Wavelet Transform Threshold Noise Reduction Methods in the Oil Pipeline Leakage Monitoring and Positioning System

This paper investigates the wavelet transform and the principle and method of the noise reduction based on wavelet transform, chooses the threshold noise reduction, and discusses detailed the principles, features and design steps of the threshold method. Rigrsure, heursure, sqtwolog and minimaxi 4 kinds of threshold selection methods are compared qualitatively and quantitatively. The wavelet analysis toolbox of MatLAB helps to realize the computer simulation of the signal noise reduction. The graphics and calculated standard deviation of the various threshold noise reductions show that, when dealing with the actual pressure signal of the oil pipeline leakage, sqtwolog threshold selection method can effectively remove the noise. Aimed to the pressure signal of the oil pipeline leakage, the best choice is the wavelet threshold noise reduction with sqtwolog threshold. The leakage point is closet to the actual position, with the relative error of less than 1%.