Brillouin spectrum recognition based on energy distribution

Abstract

The invention provides a Brillouin spectrum recognition based on energy distribution. The recognition method comprises the steps of determining Brillouin spectrum test data as L; selecting a corresponding energy integral window width W according to a detection pulse width PW to obtain energy density data P; searching a frequency range SW of the highest energy density from the energy density data P; calculating whether the peak exceeds an energy threshold PT or not in the energy density data P within the frequency range SW of the highest energy density; and searching the frequency point corresponding to the peak in the energy density data P within the highest frequency range. By means of the scheme, on one hand, curve fitting and spectral analysis are performed on data containing Brillouin spectrums only according to judgment results, a lot of meaningless Brillouin spectrum analysis processes are avoided, overall data output time is saved, and the overall test speed is increased; and on the other hand, the analysis accuracy of the Brillouin spectrums is improved under the condition of various signal to noise ratios, and the strain test accuracy is improved.

Description

technical field [0001] The invention belongs to the technical field of Brillouin spectrum recognition, and in particular relates to a Brillouin spectrum recognition method based on energy distribution. Background technique [0002] In the optical fiber sensing system, the optical fiber strain distribution tester (abbreviated as BOTDR) is an indispensable testing instrument, which is widely used in the health status monitoring of bridges, dams, buildings and other structures, as well as the regional safety monitoring of oil, coal mines, pipelines, etc. field. The basic principle is to inject pulsed light from one end of the fiber and receive the spontaneous Brillouin scattered light returned from each point along the fiber. After time domain sampling and analysis, the spectrum of the Brillouin scattered light at each point along the line can be obtained, and then analyzed The frequency shift is obtained, and then through calculation, the strain distribution of each point alo...

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Problems solved by technology

In the process of determining the center position of the Brillouin spectrum of each point, the usual practice is to directly pass all the data collected in the test range to find the maximum value. This method has two problems: one is due to the interference of circuit noise, The center position of the Brillouin spectrum determined by finding the maximum value of the collected data sometimes deviates greatly from the real position, especially in the case of poor signal-to-noise ratio. This phenomenon is more obvious, which will lead to subsequent Los Angeles The results of Lenz curve fitting and Brillouin spectrum analysis have large errors, which lead to wrong strain calculation results; , the sampling data beyond the length of the fiber is Gaussian noise, without any useful information, there is no need for complex Lorenz curve fitting and Brillouin scattering spectrum analysis, which will only take up a lot of unnecessary data processing time, thus affecting overall test speed

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