基于FFT及IFFT的超声波相位差检测方法
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摘要
噪声和波形畸变是影响超声波相位差检测精度的两大主要原因,也是在时域中构建相位差检测模型必须要解决的关键问题。提出一种非整周数据整周期化的算法,在获取两路超声波A/D数据后,首先对非整周期采样数据进行插值,将非整周期采样的数据转化为整周期采样数据,之后将整周期数据经过快速傅里叶变换(FFT)在频域中滤除噪声和波形畸变后,再通过快速傅里叶逆变换(IFFT)由频域回到时域中进行相位差检测。实验数据表明,采用FFT及IFFT的时域-频域-时域变换的超声波相位差检测法,其相位差检测精度明显优于时域法相位差检测精度,当选用12位A/D采样超声波数据时,相位差的检测标准差<0. 01°。
Noise and waveform distortion are two main factors which affect the accuracy of ultrasonic phase difference detection. They are also the key issues that must be solved to construct phase difference detection model in the time domain. An algorithm for transforming non-integer period sampled data into integer period sampled data is proposed. After acquiring two routes of ultrasonic A/D data,the noninteger period sampling data are interpolated,converting non-integer period sampled data into integer period sampled data. After filtering noise and waveform distortion by fast Fourier transform( FFT),phase difference detection is carried out by Inverse fast Fourier transform( IFFT) from frequency domain to time domain. The experimental data show that the FFT and IFFT time domain-frequency domain-time domain transformations are used to detect the phase difference of ultrasound. And the accuracy of phase difference detection is obviously better than that of time domain method. When 12-bit A/D is used as sample ultrasonic data,the standard deviation of phase difference is less than 0. 01 degree.
Noise and waveform distortion are two main factors which affect the accuracy of ultrasonic phase difference detection. They are also the key issues that must be solved to construct phase difference detection model in the time domain. An algorithm for transforming non-integer period sampled data into integer period sampled data is proposed. After acquiring two routes of ultrasonic A/D data,the noninteger period sampling data are interpolated,converting non-integer period sampled data into integer period sampled data. After filtering noise and waveform distortion by fast Fourier transform( FFT),phase difference detection is carried out by Inverse fast Fourier transform( IFFT) from frequency domain to time domain. The experimental data show that the FFT and IFFT time domain-frequency domain-time domain transformations are used to detect the phase difference of ultrasound. And the accuracy of phase difference detection is obviously better than that of time domain method. When 12-bit A/D is used as sample ultrasonic data,the standard deviation of phase difference is less than 0. 01 degree.
引文
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[2]靳世久,杨晓霞,陈世利,等.超声波相控阵检测技术的发展与应用[J].电子测量与仪器学报,2014,28(9):925-934.JIN SH J,YANG X X,CHEN SH L,et al.Developmentan application of ultrasonic phased array inspection technology[J].Journal of Electronic Measurement and Instrument,2014,28(9):925-934.
[3]兰羽.具有温度补偿功能的超声波测距系统设计[J].电子测量技术,2013,31(7):147-150.LAN Y.Design of ultrasonic ranging system with thefunction of temperature compensation[J].Electronic Measurement Technology,2013,36(2):85-87.
[4]陈建,孙晓颖,林琳,等.一种高精度超声波到达时刻的检测方法[J].仪器仪表学报,2016,37(2):263-269.CHEN J,SUN X Y,LIN L,et al.Method to precisely measure arrival time of ultrasonic[J].Chinese Journal of Scientific Instrument,2012,33(11):2422-2428.
[5]沈廷鳌,李明,李华南,等.基于相关和Hilbert变换的科氏流量计相位差估计方法[J].仪器仪表学报,2017,38(12):2908-2914.SHEN T A,LI M,LI H N,et al.Phase difference estimation method for Coriolis mass flowmeter based on correlation and Hilbert transform[J].Chinese Journal of Scientific Instrument,2017,38(12):2908-2914.
[6]谢尚豪,张硕,许波.一种高精度频率测量电路设计[J].电子测量技术,2018,41(18):115-121.XIE SH H,ZHANG SH,XU B.Design of high precision frequency measurement circuit[J].Electronic Measurement Technology,2018,41(18):115-121.
[7]邓澈,颜晗,华波,等.基于FPGA的叶尖间隙信号高速采集与处理方法[J].电子测量与仪器学报,2018,32(3):104-110.DENG CH,YAN H,HUA B,et al.High speed acquisition and processing method for tip clearance signal based on FPGA[J].Journal of Electronic Measurement and Instrument,2018,32(3):104-110.
[8]涂亚庆,沈廷鳌,李明,等.基于多次互相关的非整正周期信号相位差测量算法[J].仪器仪表学报,2014,35(7):1578-1585.TU Y Q,SHEN T A,LI M,et al.Separation algorithm for Moiréfringe signal errors based on single-variable recursive method[J].Chinese Journal of Scientific Instrument,2012,33(8):1708-1713.
[9]徐昌荣.基于FPGA的高速FFT实现研究[J].国外电子测量技术,2018,37(3):22-25.XU CH R.Research on high speed FFT implementation based on FPGA[J].Foreign Electronic Measurement Technology,2018,37(3):22-25.
[10]宋成军,何玉珠.基于最小二乘法的控制舱相位差测量技术[J].电子测量技术,2014,37(1):138-141.SONG CH J,HE Y ZH,Phase difference measurement technology of control cabin based on least square method[J].Electronic Measurement Technology,2014,37(1):138-141.
[11]陈钟鹏,华玲.一种多通道直接数字频率合成器的设计[J].电子与封装,2018,18(4):48-51.CHEN ZH P,HUA L.Design of a multichannel direct digital frequency synthesizer[J].Electronic and Packaging,2018,18(4):48-51.
[12]刘玉周,赵斌.移相相关法计算相位差的研究[J].激光技术,2014,38(5):638-642.LIU Y ZH,ZHAO B.Study on phase difference calculation by phase-shift correlation method[J].Journal of Electronic Measurement and Instrument,Laser Technology,2012,26(3):187-191.
[13]邹建,林强,王二锋.基于FPGA的波形发生器设[J].电子测量技术,2012,35(7):47-50.ZOU J,LIN Q,WANG ER F.Design of wave generator based on FPGA[J]Electronic Measurement Technology,2012,35(7):47-50.
[14]李道江,陈航,刘强,等.阵元间互辐射对基阵指向性的影响研究及试验[J].声学学报,2015,36(2):287-293.LI D J,CHEN H,LIU Q,et al.Design and research of precise macro/micro combined absolute optical encoder[J].Journal of Applied Optics,2015,36(2):287-293.
[15]徐平,王道档,解钟敏,等.基于相位偏折术的大像差透射波前检测[J].仪器仪表学报,2018,39(9):99-105.XU P,WANG D D,XIE Z M,et al.Large-aberrated transmitted wavefront test based on phase measuring deflectometry[J].Chinese Journal of Scientific Instrument,2018,39(9):99-105.
[16]徐从裕,王诗豪,吴晓凤.基于超声波A/D采样法的相位差位移测量方法[J].计量学报,2016,37(6):559-562.XU C Y,WANG SH H,WU X F.Phase difference displacement measurement method based on ultrasonic A/D sampling method[J].Acta Metrologica Sinica,2016,37(6):559-562.