基于小波变换的超声到达时刻检测
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摘要
针对目前超声到达时刻的测量精度不高,提出了一种基于小波变换的超声到达时刻的检测方法。采用DSP技术,以TMS320VC5402作为控制芯片简化硬件设计,提高数据处理能力;进行信号有效范围检验,A/D采集超声回波数据,利用小波变换方法对超声波回波信号进行去噪处理;提出了基于能量阈值法的基峰确定的过零检测方法,精确计算超声波传输时间。实验表明,该方法能够实现ns级精度的检测,为超声测距、气体流量及浓度检测、压力检测等超声检测提供一种高精度的实时性的检测方法。
The measurement accuracy of ultrasonic arrival time has yet to be improved presently. To solve this problem,a measurement method of ultrasonic arrival time was proposed,which was based on wavelet transform. The DSP was used to simplify the hardware design and improve the data processing capability with TMS320 VC5402 as the control chip. The valid range of the signal was tested,the ultrasonic echo data was collected by A/D,and the ultrasonic echo signal was denoised by the wavelet transform method. The zero-crossing measurement method of determining the reference peak based on energy threshold method was proposed to accurately calculate the ultrasonic transmission time. Experimental results show that the proposed method can achieve the ns-level time measurement accuracy and provides a high precision and real time measurement method for ultrasonic distance measurement,gas flow and concentration measurement,pressure measurement and other ultrasonic measurement methods.
The measurement accuracy of ultrasonic arrival time has yet to be improved presently. To solve this problem,a measurement method of ultrasonic arrival time was proposed,which was based on wavelet transform. The DSP was used to simplify the hardware design and improve the data processing capability with TMS320 VC5402 as the control chip. The valid range of the signal was tested,the ultrasonic echo data was collected by A/D,and the ultrasonic echo signal was denoised by the wavelet transform method. The zero-crossing measurement method of determining the reference peak based on energy threshold method was proposed to accurately calculate the ultrasonic transmission time. Experimental results show that the proposed method can achieve the ns-level time measurement accuracy and provides a high precision and real time measurement method for ultrasonic distance measurement,gas flow and concentration measurement,pressure measurement and other ultrasonic measurement methods.
引文
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[2]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,2012,33(11):2422-2428.
[3]张兴红,张慧,陈锡侯,等.一种精密测量超声波传输时间的方法[J].北京理工大学学报,2011,31(6):717-721.
[4]张红丽,和卫星,郁永斌.新型超声波氧气浓度计[J].仪表技术与传感器,2014(1):41-43.
[5]NORLI P,LUNDE P,VESTRHEIM M.Inves-tigation of precision sound velocity measurement methods as reference for ultrasonic gas flow meters[J].IEEE Ultrasonics Symposium,2015(5):1443-1447.
[6]ZHU W J,XU K J,FANG M,et al.Mathematical modeling of ultrasonic gas flow meter based on experimental data in three steps[J].IEEE Transactions on Instrumentation and Measurement,2016,65(8):1726-1738.
[7]赵刚.基于DSP的时差法气体超声波流量计的设计[D].天津:河北工业大学,2014.