A two-level detection algorithm for optical fiber vibration

Fukun Bi,Ruiqing Jiang,Xuecong Ren,Hongquan Qu

doi:10.1007/s13320-015-0263-y

Fukun Bi, Ruiqing Jiang + Show 2 more

Open Access

https://doi.org/10.1007/s13320-015-0263-y

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Journal: Photonic Sensors	Publication Date: Jul 8, 2015
Citations: 9	License type: CC BY 4.0

Affiliation: North China University of Technology

Abstract

Optical fiber vibration is detected by the coherent optical time domain reflection technique. In addition to the vibration signals, the reflected signals include clutters and noises, which lead to a high false alarm rate. The “cell averaging” constant false alarm rate algorithm has a high computing speed, but its detection performance will be declined in nonhomogeneous environments such as multiple targets. The “order statistics” constant false alarm rate algorithm has a distinct advantage in multiple target environments, but it has a lower computing speed. An intelligent two-level detection algorithm is presented based on “cell averaging” constant false alarm rate and “order statistics” constant false alarm rate which work in serial way, and the detection speed of “cell averaging” constant false alarm rate and performance of “order statistics” constant false alarm rate are conserved, respectively. Through the adaptive selection, the “cell averaging” is applied in homogeneous environments, and the two-level detection algorithm is employed in nonhomogeneous environments. Our Monte Carlo simulation results demonstrate that considering different signal noise ratios, the proposed algorithm gives better detection probability than that of “order statistics”.

Highlights

Optical fiber vibration can be detected by the coherent optical time domain reflection technique which employs coherent detection [1], and the weak backscattering signal can be extracted effectively
For signals detected by the COTDR technique, a research by using the Constant false alarm rate (CFAR) detection algorithm to decrease the false alarm rate of detection signals is presented
An adaptive CFAR algorithm based on ordered data variability has been proposed

Summary

Introduction

Optical fiber vibration can be detected by the coherent optical time domain reflection technique which employs coherent detection [1], and the weak backscattering signal can be extracted effectively. Based on variability index (VI) CFAR [10], the modified algorithm was proposed in [11,12,13] These methods utilize a background estimation algorithm which is a composite of the CA-CFAR, SO-CFAR, and GO-CFAR approaches, and take advantage of the excellent homogeneous environment performance. The above detection algorithms need to be detected only once, which cannot balance multiple problems For these problems that CA-CFAR exhibits severe performance degradation in the presence of multiple targets and the OS-CFAR costs long time for sorting, an adaptive CFAR is firstly proposed in this paper. In this algorithm, the homogeneity of background is estimated before detection. The performance is analyzed by Monte Carlo simulation, so that the feasibility and the availability can be proved

Principle of adaptive selection detection

N i 1

Analysis of performance

Conclusions