WO2019019735A1 - 基于光频域反射长距离光纤分布式扰动传感信号处理方法 - Google Patents

基于光频域反射长距离光纤分布式扰动传感信号处理方法 Download PDF

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WO2019019735A1
WO2019019735A1 PCT/CN2018/084568 CN2018084568W WO2019019735A1 WO 2019019735 A1 WO2019019735 A1 WO 2019019735A1 CN 2018084568 W CN2018084568 W CN 2018084568W WO 2019019735 A1 WO2019019735 A1 WO 2019019735A1
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disturbance
distance
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noise reduction
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刘柯
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天津求实飞博科技有限公司
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre

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  • the invention belongs to the technical field of optical fiber sensors, and in particular relates to a distributed disturbance sensing signal processing method based on optical frequency domain reflection long-distance fiber.
  • Long-distance distributed disturbance sensing is widely used in many fields such as people's death and national defense security, such as aircraft, spacecraft, ships, defense equipment, industrial equipment, bridge culverts and other key parts of structural health monitoring, using optical frequency domain reflection
  • the medium-mode fiber Rayleigh scattering spectrum shift can realize long-distance distributed disturbance sensing with high precision and high spatial resolution.
  • the present invention aims to propose a distributed disturbance sensing signal processing method based on optical frequency domain reflection long-distance fiber to overcome the existing multi-point disturbance location in optical fiber disturbance sensing based on optical frequency domain reflection. Unable to distinguish, the noise of the sensing signal is large and the spatial resolution is not high.
  • step S1 is specifically as follows:
  • the signal is grouped by time and distance as an image
  • S104 Performing noise reduction processing on the image by using a local mean filtering method, and taking an average value of the time domain information corresponding to each position, and synthesizing into one distance domain information.
  • the Fourier transform is performed on the distance domain signal, the high frequency information is zeroed, and then inversely transformed back into the distance domain to obtain a low-pass noise reduction effect, and the concave valley in the back-reverse Rayleigh scattering distance domain signal is searched for, and the concave valley position is obtained. That is, the second point of the disturbance position, the multi-point disturbance is distinguished by the above method.
  • the method for processing distributed disturbance sensing signals based on optical frequency domain reflection long-distance fiber has the following advantages:
  • the method for processing distributed disturbance sensing signals based on optical frequency domain reflection long-distance fiber utilizes an image processing method to effectively reduce noise and preserve disturbance characteristic information.
  • the noise reduction method without spatial resolution loss uses low-pass filtering to reduce noise, and the disturbance position is more prominent under the condition of ensuring spatial resolution.
  • FIG. 1 is a schematic flowchart of a method for processing a distributed disturbance sensing signal based on an optical frequency domain reflection long-distance optical fiber according to an embodiment of the present invention
  • Figure 2 is an analysis image used for time-frequency analysis
  • Figure 3 is a graph of the results after denoising.
  • first”, “second”, and the like are used for the purpose of description only, and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated.
  • features defining “first”, “second”, etc. may include one or more of the features, either explicitly or implicitly.
  • "a plurality” means two or more unless otherwise stated.
  • connection In the description of the present invention, it should be noted that the terms “installation”, “connected”, and “connected” are to be understood broadly, and may be fixed or detachable, for example, unless otherwise explicitly defined and defined. Connected, or integrally connected; can be mechanical or electrical; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of the two components.
  • Connected, or integrally connected can be mechanical or electrical; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of the two components.
  • the specific meaning of the above terms in the present invention can be understood by a person of ordinary skill in the art.
  • the method for processing distributed disturbance sensing signals based on optical frequency domain reflection long-distance fiber is as follows:
  • the beat frequency interference signal is formed by the fiber back to Rayleigh scattering, and the beat frequency interference signal is segmented along the time axis, and the fast Fourier transform is respectively performed.
  • Frequency analysis method the signal is taken as an image with time and distance as an axis;
  • the system used includes: GPIB control module, computer, main interferometer, additional interferometer, acquisition device, tunable light source.
  • the main interferometer is the core of the optical frequency domain reflectometer, which is a modified Mach Zeide interferometer.
  • the computer controls the tunable laser to control the tuning speed, the center wavelength, the tuning start, etc. through the GPIB control module; the illuminating laser emits light by the optical frequency domain reflectometer to sense the optical fiber disturbance information and output the signal light, and the acquisition device Receiving, the collecting device transmits the collected analog electrical signal to the computer.
  • the principle of disturbance sensing is to assume that there is a disturbance event at a certain position in the fiber to be tested, and its vibration will cause a change in the phase of the test light field E in the test arm and a change in the loss reflectance R.
  • the phase change caused by vibration can be expressed as:
  • f_m is the vibration frequency and ⁇ is the modulation amplitude of the phase.
  • the loss reflectivity is also attenuated by vibration, causing the amplitude of the distance domain signal to decrease.
  • the novel algorithm for measuring multi-point perturbation of long-distance fiber distributed sensing is proposed by the invention, that is, the perturbation position detection is performed by using the above principle characteristics.
  • the principle of image processing for time-frequency analysis of disturbance signals is to divide the beat frequency interference signal along the time axis and perform fast Fourier transform to form a two-dimensional signal with time and frequency bivariate, and use this two-dimensional signal as an image. Process it.
  • the method of local mean filtering is used to effectively reduce the noise of the sensing signal and retain the disturbance characteristic information.
  • the horizontal and vertical coordinates are respectively a two-dimensional image of time and distance, and the upper image is a processed image of local mean filtering in the following figure, and the visible noise is obviously suppressed.
  • the distance domain image is restored after processing.

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  • Length Measuring Devices By Optical Means (AREA)
  • Instruments For Measurement Of Length By Optical Means (AREA)

Abstract

公开了一种基于光频域反射长距离光纤分布式扰动传感信号处理方法，包括步骤：S1、利用图像处理方法，对测量信号进行降噪强化特征处理；S2、采用无空间分辨率损失的降噪方法，并利用低通滤波降噪，在保证了空间分辨率的情况下，使扰动位置更加明显突出,从而分辨多点扰动。基于光频域反射长距离光纤分布式扰动传感信号处理方法利用图像处理方法有效降低噪声并保留扰动特征信息。分辨多点扰动时，无空间分辨率损失的降噪方法，利用低通滤波降噪，在保证了空间分辨率的情况下，使扰动位置更加明显突出。

Description

基于光频域反射长距离光纤分布式扰动传感信号处理方法 技术领域
本发明属于光纤传感器技术领域，尤其是涉及一种基于光频域反射长距离光纤分布式扰动传感信号处理方法。
背景技术
长距离的分布式扰动传感广泛应用于民生、国防安全等多个领域中，如飞行器、航天器、船舶、国防装备、工业设备、桥梁涵洞等重点部位的结构健康监控，利用光频域反射中单模光纤瑞利散射光谱移动可实现高精度高空间分辨率的长距离的分布式扰动传感。
而现有基于光频域反射的光纤扰动传感中，大多存在多点扰动位置无法区分，传感信号噪声较大以及空间分辨率不高等问题。
发明内容
有鉴于此，本发明旨在提出一种基于光频域反射长距离光纤分布式扰动传感信号处理方法，以克服现有基于光频域反射的光纤扰动传感中，大多存在多点扰动位置无法区分，传感信号噪声较大以及空间分辨率不高等问题。
为达到上述目的，本发明的技术方案是这样实现的：
一种基于光频域反射长距离光纤分布式扰动传感信号处理方法，S1、利用图像处理方法，对测量信号进行降噪强化特征处理；
S2、采用无空间分辨率损失的降噪方法，并利用低通滤波降噪，在保证了空间分辨率的情况下，使扰动位置更加明显突出,从而分辨多点扰动。
进一步的，所述步骤S1的执行方法，具体如下：
S101、在光频域反射仪的主干涉仪中由光纤背向瑞利散射形成拍频干涉信号；
S102、对这拍频干涉信号沿时间轴切分，分别进行快速傅里叶变换；
S103、以时频分析方法，将信号以时间、距离为轴组为图像；
S104、对图像利用局部均值滤波方法进行降噪处理，对每一位置所对应时域信息取均值，合成为一路距离域信息。
进一步的，所述分辨多点扰动的方法，具体如下：
对距离域信号进行傅立叶变换，将高频信息置零，再逆变换回距离域，获得低通降噪效果，寻找处理后背向瑞利散射距离域信号中的凹陷波谷，该凹陷波谷位置即为第二点扰动位置，以上述方法区分多点扰动。
相对于现有技术，本发明所述的基于光频域反射长距离光纤分布式扰动传感信号处理方法具有以下优势：
本发明所述的基于光频域反射长距离光纤分布式扰动传感信号处理方法利用图像处理方法有效降低噪声并保留扰动特征信息。分辨多点扰动时，无空间分辨率损失的降噪方法，利用低通滤波降噪，在保证了空间分辨率的情况下，使扰动位置更加明显突出。
附图说明
构成本发明的一部分的附图用来提供对本发明的进一步理解，本发明的示意性实施例及其说明用于解释本发明，并不构成对本发明的不当限定。在附图中：
图1为本发明实施例所述的基于光频域反射长距离光纤分布式扰动传感信号处理方法流程示意图；
图2为时频分析所用到分析图像；
图3为去噪后的结果图。
具体实施方式
需要说明的是，在不冲突的情况下，本发明中的实施例及实施例中的特征可以相互组合。
在本发明的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了 便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。此外，术语“第一”、“第二”等仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”等的特征可以明示或者隐含地包括一个或者更多个该特征。在本发明的描述中，除非另有说明，“多个”的含义是两个或两个以上。
在本发明的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以通过具体情况理解上述术语在本发明中的具体含义。
下面将参考附图并结合实施例来详细说明本发明。
如图1所示，基于光频域反射长距离光纤分布式扰动传感信号处理方法，具体步骤如下：
(1)在光频域反射仪的主干涉仪中由光纤背向瑞利散射形成拍频干涉信号，并对这拍频干涉信号沿时间轴切分，分别进行快速傅里叶变换，以时频分析方法，将信号以时间、距离为轴组为图像；
(2)对图像利用局部均值滤波方法进行降噪处理，对每一位置所对应时域信息取均值，合成为一路距离域信息；
(3)针对多点扰动，对距离域信号进行傅立叶变换，将高频信息置零，再逆变换回距离域，获得低通降噪效果。寻找处理后背向瑞利散射距离域信号中的凹陷波谷，该凹陷波谷位置即为第二点扰动位置，以上述方法区分多点扰动。
采用的系统包含：GPIB控制模块、计算机、主干涉仪、附加干涉仪、采集装置、可调谐光源。其中主干涉仪是光频域反射仪的核心，其为改进型马赫泽德干涉仪。
系统工作原理：
装置工作时，计算机通过GPIB控制模块控制可调谐激光器控制调谐速度、中心波 长、调谐启动等；可调谐激光器的出射光由光频域反射仪传感光纤扰动信息并输出信号光，并由采集装置接收，采集装置将采集到的模拟电信号传输至计算机。
扰动传感的原理是，假设在待测光纤中的某一位置存在一扰动事件，其振动会引起测试臂中测试光场E的相位变化及损耗反射率R的变化。振动引起的相位变化可以表示为：
Figure PCTCN2018084568-appb-000001
其中，f_m是振动频率，δ是相位的调制幅度。而损耗反射率亦因振动而衰减，造成距离域信号幅值下降。本发明所提出的针对长距离光纤分布式传感测量多点扰动的新型算法，即利用上述原理特性进行扰动位置检测。
针对扰动信号时频分析图像处理的原理是，对拍频干涉信号沿时间轴切分，分别进行快速傅里叶变换，进而形成时间、频率双变量的二维信号，将此二维信号作为图像进行处理。利用局部均值滤波的方法，有效地减小传感信号噪音，并保留扰动特征信息。
如图2所示，为横纵坐标分别为时间与距离的二维图像，上图为下图作局部均值滤波的处理后图像，可见噪音被明显抑制。如图3所示，为处理后还原的距离域图像。
以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (3)

  1. 基于光频域反射长距离光纤分布式扰动传感信号处理方法，其特征在于，包括以下步骤：
    S1、利用图像处理方法，对测量信号进行降噪强化特征处理；
    S2、采用无空间分辨率损失的降噪方法，并利用低通滤波降噪，在保证了空间分辨率的情况下，使扰动位置更加明显突出,从而分辨多点扰动。
  2. 根据权利要求1所述的基于光频域反射长距离光纤分布式扰动传感信号处理方法，其特征在于，所述步骤S1的执行方法，具体如下：
    S101、在光频域反射仪的主干涉仪中由光纤背向瑞利散射形成拍频干涉信号；
    S102、对这拍频干涉信号沿时间轴切分，分别进行快速傅里叶变换；
    S103、以时频分析方法，将信号以时间、距离为轴组为图像；
    S104、对图像利用局部均值滤波方法进行降噪处理，对每一位置所对应时域信息取均值，合成为一路距离域信息。
  3. 根据权利要求1所述的基于光频域反射长距离光纤分布式扰动传感信号处理方法，其特征在于，所述分辨多点扰动的方法，具体如下：
    对距离域信号进行傅立叶变换，将高频信息置零，再逆变换回距离域，获得低通降噪效果，寻找处理后背向瑞利散射距离域信号中的凹陷波谷，该凹陷波谷位置即为第二点扰动位置，以上述方法区分多点扰动。
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CN110160569B (zh) * 2019-04-24 2021-09-24 国网浙江省电力有限公司信息通信分公司 用于分布式光纤传感信号的降噪方法、系统及存储介质
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