scholarly journals Two-Parameter Elliptical Fitting Method for Short-Cavity Fiber Fabry–Perot Sensor Interrogation

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 36 ◽  
Author(s):  
Xiongxing Zhang ◽  
Wei Wang ◽  
Haibin Chen ◽  
Ying Tang ◽  
Zhibo Ma ◽  
...  
Keyword(s):  
White Light ◽  
Cavity Length ◽  
Processing Method ◽  
Light Sources ◽  
Fitting Method ◽  
Data Processing Method ◽  
Fabry Perot ◽  
Gap Sensors ◽  
Two Parameter ◽  
Better Than

To solve the cavity interrogation problem of short cavity fiber Fabry–Perot sensors in white light spectral interrogation with amplified spontaneous emissions (ASEs) as the white light sources, a data processing method, using an improved elliptical fitting equation with only two undetermined coefficients, is proposed. Based on the method, the cavity length of a fiber Fabry–Perot sensor without a complete reflection spectrum period in the frequency domain can be interrogated with relatively high resolution. Extrinsic fiber Fabry–Perot air-gap sensors with cavity lengths less than 30 μm are used to experimentally verify the method, and are successfully interrogated with an accuracy better than 0.55%.

scholarly journals Demodulation Method of F-P Sensor Based on Wavelet Transform and Polarization Low Coherence Interferometry

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4249
Author(s):  
Jiwen Cui ◽  
Yizhao Niu ◽  
Hong Dang ◽  
Kunpeng Feng ◽  
Xun Sun ◽  
...  
Keyword(s):  
Cavity Length ◽  
Sampling Interval ◽  
Low Coherence ◽  
Low Coherence Interferometry ◽  
Data Processing Method ◽  
Fabry Perot ◽  
Complex Morlet Wavelet ◽  
Influence Of Noise ◽  
Demodulation Method ◽  
Better Than

Polarized low-coherence interferometry (PLCI) is widely used for the demodulation of Fabry–Perot (F-P) sensors. To avoid the influence of noise and dispersion on interference fringes, this paper proposes a data processing method in which the wavelet tools are applied to extract useful information from the extremum locations and envelope center of the fringes. Firstly, the wavelet threshold denoising (WTD) algorithm is used to remove electrical noise, and the complex Morlet wavelet is used to extract the fringe envelope. Based on this, the envelope center is used to predict the extremum locations of the specified order in its adjacent interval, the predicted locations are used as references to track the exact extremum locations, and the middle location of the peak and valley values is obtained to demodulate the F-P cavity accurately. The validity of this demodulation theory is verified by an air F-P cavity whose cavity length varies from 17 to 20 μm. With a sampling interval of 30 nm, the experimental results indicate that the repeatability accuracy is higher than 6.04 nm, and the resolution is better than 4.0 nm.

An Improved Wavelet Threshold De-Noising Data Processing Method Research in Deformation Monitoring

2011 ◽  
Vol 90-93 ◽  
pp. 2858-2863
Author(s):  
Wei Li ◽  
Xu Wang
Keyword(s):  
Data Processing ◽  
Deformation Monitoring ◽  
Processing Method ◽  
Threshold Function ◽  
Wavelet Coefficients ◽  
New Approach ◽  
Data Processing Method ◽  
Soft Threshold ◽  
Fixed Bias ◽  
Better Than

Due to the soft and hard threshold function exist shortcomings. This will reduce the performance in wavelet de-noising. in order to solve this problem，This article proposes Modulus square approach. the new approach avoids the discontinuity of the hard threshold function and also decreases the fixed bias between the estimated wavelet coefficients and the wavelet coefficients of the soft-threshold method．Simulation results show that SNR and MSE are better than simply using soft and hard threshold，having good de-noising effect in Deformation Monitoring.

Data-processing method of white-light differential interference based on wavelet transform

2005 ◽  
Author(s):  
Yongjun Nie ◽  
Huimin Yan ◽  
Yanli Du ◽  
Yong Wu ◽  
Xiaoqiang Yao ◽  
...  
Keyword(s):  
Wavelet Transform ◽  
Data Processing ◽  
White Light ◽  
Processing Method ◽  
Data Processing Method

scholarly journals Registering upper atmosphere parameters in East Siberia with Fabry—Perot Interferometer KEO Scientific “Arinae”

2017 ◽  
Vol 3 (3) ◽  
pp. 61-75 ◽  
Author(s):  
Роман Васильев ◽  
Roman Vasilyev ◽  
Максим Артамонов ◽  
Maksim Artamonov ◽  
Александр Белецкий ◽  
...  
Keyword(s):  
Wind Velocity ◽  
Line Intensity ◽  
Processing Method ◽  
Upper Atmosphere ◽  
Background Intensity ◽  
Model Data ◽  
East Siberia ◽  
Data Processing Method ◽  
Fabry Perot ◽  
Existing Data

We describe the Fabry—Perot interfero-meter designed to study Earth’s upper atmosphere. We propose a modification of the existing data processing method for determining the Doppler shift and Doppler widening and also for separating the observed line intensity and the background intensity. The temperature and wind velocity derived from these parameters are compared with physical characteristics obtained from modeling (NRLMSISE-00, HWM14). We demonstrate that the temperature is determined from the oxygen 630 nm line irrespective of the hydroxyl signal existing in interference patterns. We show that the interferometer can obtain temperature from the oxygen 557.7 nm line in case of additional calibration of the device. The ob-served wind velocity mainly agrees with model data. Night variations in the red and green oxygen lines quite well coincide with those in intensities obtained by de-vices installed nearby the interferometer.

scholarly journals Registering upper atmosphere parameters in East Siberia with Fabry—Perot Interferometer KEO Scientific “Arinae”

2017 ◽  
Vol 3 (3) ◽  
pp. 70-87 ◽  
Author(s):  
Роман Васильев ◽  
Roman Vasilyev ◽  
Максим Артамонов ◽  
Maksim Artamonov ◽  
Александр Белецкий ◽  
...  
Keyword(s):  
Wind Velocity ◽  
Processing Method ◽  
Upper Atmosphere ◽  
Background Intensity ◽  
Model Data ◽  
East Siberia ◽  
Night Time ◽  
Data Processing Method ◽  
Fabry Perot ◽  
Time Variations

We describe the Fabry—Perot interferometer designed to study Earth’s upper atmosphere. We propose a modification of the existing data processing method for determining the Doppler shift and Doppler widening and also for separating the observed line intensity and the background intensity. The temperature and wind velocity derived from these parameters are compared with physical characteristics obtained from modeling (NRLMSISE-00, HWM14). We demonstrate that the temperature is determined from the oxygen 630 nm line irrespective of the hydroxyl signal existing in interference pictures. We show that the interferometer can obtain temperature from the oxygen 557.7 nm line in case of additional calibration of the device. The observed wind velocity mainly agrees with model data. Night time variations in the red and green oxygen lines quite well coincide with those in intensities obtained by devices installed nearby the interferometer.

scholarly journals Microdisplacement Measurement Based on F-P Etalon: Processing Method and Experiments

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3749
Author(s):  
Xiaoyan Shen ◽  
Shinan Zhou ◽  
Dongsheng Li
Keyword(s):  
Data Processing ◽  
Processing Method ◽  
Displacement Measurement ◽  
Concentric Ring ◽  
Data Processing Method ◽  
Circle Centre ◽  
Fabry Perot ◽  
Coordinate Rotation ◽  
Circular Regression ◽  
Extended Uncertainty

Herein, a processing method is proposed for accurate microdisplacement measurements from a 2D Fabry–Perot (F-P) fringe pattern. The core of the processing algorithm uses the F-P interference imaging concentric ring pattern to accurately calculate the centre coordinates of the concentric ring. The influencing factors of measurement were analysed, and the basic idea of data processing was provided. In particular, the coordinate rotation by the 45-degree method (CR) was improved; consequently, the virtual pixel interval was reduced by half, and the calculation accuracy of the circle centre coordinate was improved. Experiments were conducted to analyse the influence of the subdivision and circle fitting methods. The results show that the proposed secondary coordinate rotation (SCR) by 45 degrees method can obtain higher accuracy of the centre coordinate than the CR method, and that the multichord averaging method (MCAM) is more suitable for calculation of the centre coordinate than the circular regression method (CRM). Displacement measurement experiments were performed. The results show that the standard experimental deviation of the centre of the circle is approximately 0.009 µm, and the extended uncertainty of the displacement measurement in the range of 5 mm is approximately 0.03 μm. The data processing method studied in this study can be widely used in the field of F-P interferometry.

scholarly journals Absolute Single Cavity Length Interrogation of Fiber-Optic Compound Fabry–Perot Pressure Sensors Through a White Light Non-Scanning Correlation Method

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1628 ◽  
Author(s):  
Zilong Guo ◽  
Wentao Lv ◽  
Wei Wang ◽  
Qingqing Chen ◽  
Xiongxing Zhang ◽  
...  
Keyword(s):  
Fourier Transform ◽  
White Light ◽  
Cavity Length ◽  
Fiber Optic ◽  
Pressure Sensors ◽  
Correlation Method ◽  
Air Cavity ◽  
Basal Cavity ◽  
Fabry Perot ◽  
Absolute Length

A white light non-scanning correlation interrogation system was proposed and built to interrogate absolute length of the air cavity of fiber-optic compound Fabry–Perot pressure sensors for the extraction of pressure value. By carefully choosing thickness range and tilt angle of the optical wedge used for cavity length matching, correlation interferometric signal of the basal cavity can be naturally filtered out. Based on peak positioning by Fourier transform, bandpass filtering in frequency domain, inverse Fourier transform back to time domain, envelope fitting and zero fringe finding through a gravity center method, cavity length can be determined with an accuracy of 0.04%. The system was used for the interrogation of a fiber-optic compound Fabry–Perot pressure sensor under different pressures. For a pressure range of 0.1~2.9 Mpa, the linear relationship between the air cavity length and the gas pressure imposed was successfully extracted.

Contrast Analysis of Data Processing Method Based on the MATLAB in Compaction Test

2012 ◽  
Vol 170-173 ◽  
pp. 611-614 ◽  
Author(s):  
Zhi Wei Yu ◽  
Sheng Guo Cheng
Keyword(s):  
Comparative Analysis ◽  
Data Processing ◽  
Numerical Method ◽  
Soil Compaction ◽  
Processing Method ◽  
Compaction Test ◽  
Fitting Method ◽  
Data Processing Method ◽  
Contrast Analysis ◽  
Data Points

Abstract. The data of compaction test is processed by use of numerical method and least-squares fitting method respectively through MATLAB software. After a simple comparative analysis of the two results, this paper aims to reach the conclusion that when the distribution of test data points consistent with the characteristics of soil compaction, it is better and more accurate to use numerical method.

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