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磁定向信号中畸变噪声的存在严重地影响了磁定向系统的性能。在介绍了磁定向系统工作原理,分析磁定向系统中噪声的产生和特性的基础上,将小波变换的方法应用于磁定向系统去噪,提出用小波软阈值函数对磁定向信号进行去噪处理。首先分析了信号和噪声在小波变换下统计特性的不同点,基于统计特性上的差异,对小波变换后的小波系数进行软阈值函数处理,提取那些模极大值随尺度增大而减小的系数,并保留这些系数,同时滤除模极大值与尺度无关的系数,达到滤除信号中噪声的目的。仿真结果表明:该算法能很好滤除磁定向信号中存在的畸变噪声,使得磁定向信号稳定性得到增强,最终提高了磁定向系统的性能。
The presence of distorted noise in the magnetic orientation signal seriously affects the performance of the magnetic orientation system. Based on the introduction of the working principle of the magnetic orientation system and the analysis of the generation and characteristics of the noise in the magnetic orientation system, the wavelet transform method is applied to the denoising of the magnetic orientation system. The wavelet soft threshold function is proposed to denoise the magnetic orientation signal . Firstly, the difference of statistical properties of signal and noise under wavelet transform is analyzed. Based on the difference of statistical properties, the wavelet coefficients after wavelet transform are processed by soft threshold function, and the maxima of those moduli decrease with the increase of scale Coefficients, and retain these coefficients, and filter out the maximum modulus and scale-independent coefficients, to filter out the noise signal purposes. The simulation results show that the proposed algorithm can filter out the distorted noise in the magnetic directional signal well and enhance the stability of the magnetic directional signal. Finally, the performance of the magnetic directional system is improved.