Data Acquisition And Processing Of Distributed Optical Fiber Sensor

Optical fiber sensor technology is an emerging technology developed from late 1970s, which is applied in nonlinear optic fiber field. Compared with traditional electricity sensor, optical fiber sensor technology has a lot of outstanding advantages, such as high sensitivity, anti-electromagnetic interference, non-electromagnetic interference, high temperature resistance and corrosion resistance, and so on. Based on the advantages such as non-touch measurement, high sensitivity, fast response, anti-electromagnetic interference high temperature resistance and corrosion resistance, the optical fiber sensor is widely used in the security alarm of sensitive areas. In this paper, the data acquisition and processing of distributed optical fiber vibration sensor system is analyzed and discussed both in theory and experiments.This paper studies the software of optical fiber vibration sensor system based on Mach-Zehnder interferometer, which can be primarily divided into two parts, local and remote part. The local monitor node primarily consists of physical layer, driver layer, transplanted layer and application layer. Driver layer mainly consists data acquisition card driver and DVR card SDK driver; Application layer primarily consists equipments, algorithms and controlling class etc. This paper focuses on the studies of the design and implementation of the data acquisition module based on the PCI bus, data preprocessing using two different wavelets filtering algorithms, and proposing a new algorithm of the data processing.A new signal acquisition mode is adopted in the distributed optical fiber vibration sensor system which ensures this sensor compatible under different types of collection cards used. The signal preprocessing part use haar wavelet filtering and daubechies wavelet filtering, two methods to reduce the noise against effective signal. It can inhibit the effect of noise mostly by wavelet filtering, which made signal match the model of database more precisely, also reduce the rate of error alarm. This paper provides a new algorithm using ellipse fitting algorithm to analyze output phase difference, the new algorithm can judge the category of coupler's properties and differentiate the type of signal. Not only is this algorithm easy to understand, but also it can inhibit the output phase difference between two optical paths due to the coupler itself, what's more, it raises the accuracy to identify different kinds of signal.