Detection of Ground Movement using the Shape of Brillouin Spectrum

Buchoud, Edouard; Blairon, Sylvain; d'Urso, Guy; Hénault, Jean-Marie; Girard, Alexandre; Mars, Jérôme; Vrabie, Valériu

doi:10.3997/2214-4609.20143360

Cited by 2 publications

(3 citation statements)

References 3 publications

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“…Our previous studies have strengthened the observation and quantification of the Brillouin distortion phenomena within industrial devices under semi-controlled conditions [18]. In this report, we propose another model that is based on signal-processing techniques.…”

Section: Introductionmentioning

confidence: 66%

“…So the Brillouin spectrum contains multiple peaks for non-constant strain within w, whereas the spectrum is a single peak if the strain is constant. This phenomenon has been seen and quantified with experimental data acquired under controlled conditions [16]- [18]. This also highlights the limits of the industrial device: the algorithm of the industrial B-OTDA device does not take into account the Brillouin distortion.…”

Section: Brillouin Distortion Phenomenonmentioning

confidence: 73%

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Enhancement of an Optical Fiber Sensor: Source Separation Based on Brillouin Spectrum

et al. 2013

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International audienceDistributed optical fiber sensors have gained an increasingly prominent role in structural-health monitoring. These are composed of an optical fiber cable in which a light impulse is launched by an opto-electronic device. The scattered light is of interest in the spectral domain: the spontaneous Brillouin spectrum is centered on the Brillouin frequency, which is related to the local strain and temperature changes in the optical fiber. When coupled with an industrial Brillouin optical time-domain analyzer (B-OTDA), an optical fiber cable can provide distributed measurements of strain and/or temperature, with a spatial resolution over kilometers of 40 cm. This paper focuses on the functioning of a B-OTDA device, where we address the problem of the improvement of spatial resolution. We model a Brillouin spectrum measured within an integration base of 1 m as the superposition of the elementary spectra contained in the base. Then, the spectral distortion phenomenon can be mathematically explained: if the strain is not constant within the integration base, the Brillouin spectrum is composed of several elementary spectra that are centered on different local Brillouin frequencies. We propose a source separation methodology approach to decompose a measured Brillouin spectrum into its spectral components. The local Brillouin frequencies and amplitudes are related to a portion of the integration base where the strain is constant. A layout algorithm allows the estimation of a strain profile with new spatial resolution chosen by the user. Numerical tests enable the finding of the optimal parameters, which provides a reduction to 1 cm of the 40-cm spatial resolution of the B-OTDA device. These parameters are highlighted during a comparison with a reference strain profile acquired by a 5-cm-resolution Rayleigh scatter analyzer under controlled conditions. In comparison with the B-OTDA strain profile, our estimated strain profile has better accuracy, with centimeter spatial resolut ion

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Section: Introductionmentioning

confidence: 66%

Section: Brillouin Distortion Phenomenonmentioning

confidence: 73%

Enhancement of an Optical Fiber Sensor: Source Separation Based on Brillouin Spectrum

et al. 2013

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“…Output of device estimate the strain profile with a fixed rate sample distance Δz = 40cm (Fig 6.b purple curve). By applying the proposed NMF source separation, we obtain the sparsity criteria curve along the distance (fig 6a) based on [24]. This curve highlights 2 points at z 1 = 10.4 m and z 2 = 14,2 m (distances with the highest strain).…”

Section: B Real Examplementioning

confidence: 98%

Source separation and distributed sensing: The key for an efficient monitoring

Mars

Buchoud

Vrabie

et al. 2013

2013 5th IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP)

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As a complement to classical sensors, Distributed Optical Fiber Sensors now play a prominent role in several engineering fields and act as an antenna array. Depending of the devices used (Raman, Rayleigh, or Brillouin scattering), measurement record depend on temperature, strain, or pressure profile. As the wanted signal is often hidden by noise and other undesired sources, we can express the problem as a source separation problem. In this paper, we show that with the help of recent techniques based on data decomposition and source separation (PCA, ICA NMF techniques) from the virtual antenna, we can accurately identify water leakages from a noisy Raman spectra or a strain profile from Brillouin spectra with a spatial resolution of 1cm instead of 1 meter for classical devices.

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Detection of Ground Movement using the Shape of Brillouin Spectrum

Cited by 2 publications

References 3 publications

Enhancement of an Optical Fiber Sensor: Source Separation Based on Brillouin Spectrum

Enhancement of an Optical Fiber Sensor: Source Separation Based on Brillouin Spectrum

Source separation and distributed sensing: The key for an efficient monitoring

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