|本期目录/Table of Contents|

 高精度超声测距系统中自相关小波去噪法(PDF)

《纳米技术与精密工程》[ISSN:1672-6030/CN:12-1351/O3]

期数:
2016年3期
页码:
179-185
栏目:
精密测量
出版日期:
2016-05-15

文章信息/Info

Title:
 Self-Correlation Wavelet De-noising Method Used in
Highly Accurate Ultrasonic Ranging System
作者:
 李醒飞1 纪 越1 吴 军2
 1.精密测试技术及仪器国家重点实验室(天津大学),天津300072;2. 中国民航大学航空工程学院,天津300300
Author(s):
 Li Xingfei1 Ji Yue1 Wu Jun2
 1. State Key Laboratory of Precision Measuring Technology and Instruments(Tianjin University), Tianjin 300072, China;
2. Aeronautical Engineering Institute, Civil Aviation University of China, Tianjin 300300, China
关键词:
 超声测距 小波去噪 自相关 自适应阈值
Keywords:
 ultrasonic ranging wavelet de-noising self-correlation adaptive threshold
分类号:
TN820.5
DOI:
10.13494/j.npe.20160010
文献标识码:
A
摘要:
 超声测距的精度主要取决于飞行时间的提取精度,由于受噪声影响,接收信号的始点位置通常无法精确提取.传统方法常采用设计滤波器降噪,然而由于滤波器的参数无法随超声信号变化而改变,导致其适应性较差.本文提出了一种自相关小波阈值去噪的自适应去噪方法,通过计算各层小波细节分量与近似分量的相关性系数,自动确定最优分解层数,并通过采集分析噪声信号的小波分量,选择最优去噪阈值,达到了良好的去噪效果,增强了回波信号的信噪比,极大地提高了回波飞行时间的提取精度.经实验验证,信噪比可提高6~7 dB,在1 900 mm的范围内测量误差小于0.3 mm,测量不确定度小于0.17 mm.与传统方法相比,本方法具有适应性强、始点识别率高、测距精确等优点.
Abstract:
 The accuracy of ultrasonic ranging system is mainly determined by the accuracy of flight time of ultrasonic echo wave. The onset of the received signal cannot always be extracted accurately because of noise interference. The main disadvantage of traditional de-noising methods through designing filters is that the parameters are fixed rendering its adaptability much weaker. A wavelet de-noising method using self-correlation is presented in this paper. The method adopts the optimal wavelet decomposition level based on the correlation of coefficient between the detail component and approximation component, and then the optimal de-noising threshold is determined based on analyzing the noise signal. Therefore, this method greatly improves the SNR, and enhances the accuracy of flight time. The experiment proves that the SNR of the echo signal could be improved by 6—7 dB and the accuracy of the ultrasonic ranging system is better than 0.3 mm, while the uncertainty is better than 0.17 mm for the distance up to 1 900 mm. Compared with traditional methods, this method enjoys such advantages as strong adaptability, high onset extraction recognition and ranging accuracy.

参考文献/References

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备注/Memo

备注/Memo:
 收稿日期: 2016-02-18.
基金项目: 国家自然科学基金与民航联合基金资助项目(U1533111);中国民航大学科研启动基金资助项目(2014QD09X).
作者简介: 李醒飞(1966— ),男,博士,教授.
通讯作者: 纪 越,博士,jiyue@tju.edu.cn.
更新日期/Last Update: 2016-05-13