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Fiber optic system design for vehicle detection and analysis
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Paper Abstract

Fiber optic interferometers belong to a group of highly sensitive and precise devices enabling to measure small changes in the deformation shapes, changes in pressure, temperature, vibration and so on. The basis of their activity is to evaluate the number of fringes over time, not changes in the intensity of the optical signal. The methodology described in the article is based on using the interferometer to monitor traffic density. The base of the solution is a Mach-Zehnder interferometer operating with single-mode G.652 optical fiber at the wavelength of 1550 nm excited by a DFB laser. The power distribution of the laser light into the individual arms of the interferometer is in the ratio 1:1. Realized measuring scheme was terminated by an optical receiver including InGaAs PIN photodiode. Registered signal from the photodetector was through 8 Hz high pass filter fed to the measuring card that captures the analog input voltage using an application written in LabView development environment. The interferometer was stored in a waterproof box and placed at the side of the road. Here panned individual transit of cars in his environs. Vertically across the road was placed in contact removable belt simulating a retarder, which was used when passing cars to create sufficient vibration response detecting interferometer. The results demonstrated that the individual vehicles passing around boxing showed characteristic amplitude spectra, which was unique for each object, and had sufficient value signal to noise ratio (SNR). The signal was processed by applications developed for the amplitude-frequency spectrum. Evaluated was the maximum amplitude of the signal and compared to the noise. The results were verified by repeated transit of the different types of cars.

Paper Details

Date Published: 27 April 2016
PDF: 8 pages
Proc. SPIE 9889, Optical Modelling and Design IV, 98892D (27 April 2016); doi: 10.1117/12.2239549
Show Author Affiliations
Jan Nedoma, VŠB-Technical Univ. of Ostrava (Czech Republic)
Ondrej Zboril, VŠB-Technical Univ. of Ostrava (Czech Republic)
Marcel Fajkus, VŠB-Technical Univ. of Ostrava (Czech Republic)
Petr Zavodny, VŠB-Technical Univ. of Ostrava (Czech Republic)
Stanislav Kepak, VŠB-Technical Univ. of Ostrava (Czech Republic)
Lukas Bednarek, VŠB-Technical Univ. of Ostrava (Czech Republic)
Radek Martinek, VŠB-Technical Univ. of Ostrava (Czech Republic)
Vladimir Vasinek, VŠB-Technical Univ. of Ostrava (Czech Republic)

Published in SPIE Proceedings Vol. 9889:
Optical Modelling and Design IV
Frank Wyrowski; John T. Sheridan; Youri Meuret, Editor(s)

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