| Brillouin Optical Time Domain Reflectometry(BOTDR)is a fiber-optic distributed sensing technology,which can be used to capture the distributed information of temperature and stress along the optical fiber.Because of its many advantages such as anti-electromagnetic interference,corrosion resistance,and high sensitivity,this technology can provide dynamic temperature and stress measurement for large projects in Chemical industry,Electric energy and Construction.Since the 1970 s,researchers have never stopped exploring the technology in experimental research and engineering applications.BOTDR technology is still a research hotspot in the field of sensing.This article begins with a description of the BOTDR sensing mechanism and the key technologies.It also introduces a miniaturized sensing system that is easy to integrate,the functions and performance parameters of each device are analyzed and introduced in detail,the computer interface program and the integrated solution are given as well.At the same time,FPGA hardware design completes the development of modules such as data acquisition,data overlay,and data upload,by combining with the external hardware that provides trigger signal,FPGA(Field-Programmable Gate Array)also achieves the synchronous control of the system.In addition,a segmentation-based wavelet denoising approach is developed to improve the temperature detection accuracy.This algorithm detects the singular signals that contain temperature sensing information through high-level wavelet analysis,then,the algorithm divides the distributed temperature information along the fiber into two sections.According to the different characteristics of the two sections of data,the wavelet-functions and decomposition-layers are selected appositely and seperately to denoise the data.By comparing and analyzing the denoised data with the original data,it verifies the effect of the segmentation-based wavelet algorithm on the accuracy of temperature measurement. |
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