Working On A Real-time And On-line Signal Acquisition And Processing System Of Photonic Doppler Velocimetry Based On LabVIEW And Matlab

Photonic doppler velocimetry system is a new kind of all fiber laser velocimetry system. It can get the velocity information by detecting the frequency shift between the reflected light from the moving surface and the reference light. PDV system is suitable for non-contact measurement. With its high time resolution, strong anti-jamming capability, large measuring range, as well as good sensitivity, this system is used widely in measurement field.In traditional photonic Doppler velocimetry system, the velocity information is generally obtained by off-line processing. The processing cycle is so long that the traditional velocimetry system can’t be used as a real-time sensing system. In order to realize the real-time measurement of the PDV system, there are several new designs in this paper in terms of the theory of photonic Doppler velocimetry. A data acquisition card is used to acquire the differential frequency signal. Matlab is used to process the differential frequency signal by the stripe method and the wavelet transform method because of its powerful numerical processing capacity, and the time-corresponding speed is obtained consequently. In the experiment, the virtual instrument software Lab VIEW is designed to call the data acquisition card and the software Matlab at the same time so that it can acquire and process the differential frequency signal and show the velocity curve in the interface together. So it realize the real-time and on-line signal acquiring, processing and displaying.Because of the uncertainty of the movement form of the moving object, different data processing methods are discussed in this paper and appropriate conditions of different methods are obtained. Besides, method options are designed in the interface of Lab VIEW so that the users can make the choices according to their needs.