Analysis of the detection materials as resonant pads for attaching the measuring arm of the interferometer when sensing mechanical vibrations

Nedoma, Jan; Fajkus, Marcel; Martínek, Radek; Zboril, Ondrej; Bednarek, Lukas; Novák, Martin; Witas, Karel; Vašinek, Vladimír

doi:10.1117/12.2257321

Cited by 2 publications

(3 citation statements)

References 5 publications

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“…Thermal phenomena, mechanical changes, and other factors generate a background signal (noise). To address this issue or more precisely the need for the reference channel (position and encapsulation) is critical according to sensor sensitivity which must be taken into account in the design of a fiber-optic interferometer [ 56 , 130 , 131 , 132 , 133 , 134 ].…”

Section: Discussionmentioning

confidence: 99%

A Phonocardiographic-Based Fiber-Optic Sensor and Adaptive Filtering System for Noninvasive Continuous Fetal Heart Rate Monitoring

Martínek

Nedoma

Fajkus

et al. 2017

Sensors

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This paper focuses on the design, realization, and verification of a novel phonocardiographic- based fiber-optic sensor and adaptive signal processing system for noninvasive continuous fetal heart rate (fHR) monitoring. Our proposed system utilizes two Mach-Zehnder interferometeric sensors. Based on the analysis of real measurement data, we developed a simplified dynamic model for the generation and distribution of heart sounds throughout the human body. Building on this signal model, we then designed, implemented, and verified our adaptive signal processing system by implementing two stochastic gradient-based algorithms: the Least Mean Square Algorithm (LMS), and the Normalized Least Mean Square (NLMS) Algorithm. With this system we were able to extract the fHR information from high quality fetal phonocardiograms (fPCGs), filtered from abdominal maternal phonocardiograms (mPCGs) by performing fPCG signal peak detection. Common signal processing methods such as linear filtering, signal subtraction, and others could not be used for this purpose as fPCG and mPCG signals share overlapping frequency spectra. The performance of the adaptive system was evaluated by using both qualitative (gynecological studies) and quantitative measures such as: Signal-to-Noise Ratio—SNR, Root Mean Square Error—RMSE, Sensitivity—S+, and Positive Predictive Value—PPV.

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Section: Discussionmentioning

confidence: 99%

A Phonocardiographic-Based Fiber-Optic Sensor and Adaptive Filtering System for Noninvasive Continuous Fetal Heart Rate Monitoring

Martínek

Nedoma

Fajkus

et al. 2017

Sensors

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“…The tested minimum value for sufficient dampening of vibration transmission to the optical fiber was determined as 5 cm, mainly because of the sensitivity and frequency range of the interferometric sensor. Further, we tested the methodologies of installing measurement and reference fibers, waterproof boxes, splitters, fastening and housing materials, and optical fiber protections; please see our publications [43][44][45][46][47].…”

Section: Interferometric Sensor Unitmentioning

confidence: 99%

“…A series of laboratory measurements were carried out to verify the effect of the thickness and size of the glass (resonant pad) on the transmission of vibrations to the measuring (L 1 ) optical fiber. A thickness of 1 cm and a size of 50 × 50 cm was selected (please see the publication [45]); these values showed a compromise with regard to sensitivity, frequency range, price, and practical installation. A photo of the fiber-optic interferometric sensor prototype is shown in Figure 3.…”

Section: Interferometric Sensor Unitmentioning

confidence: 99%

Use of Fiber-Optic Sensors for the Detection of the Rail Vehicles and Monitoring of the Rock Mass Dynamic Response Due to Railway Rolling Stock for the Civil Engineering Needs

et al. 2019

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The paper describes the original results of a comparative study of the standard seismic station vs. a novel interferometric sensor for civil engineering needs. The presented results showed that to implement seismic measurements using standard seismic stations, a method using a fiber optic interferometer may serve as an alternative. We presented time records and the frequency spectra obtained from experimental measurements of the dynamic response of the upper rock mass beneath passing tram vehicles (a total of 769 passes) over a period of five months of practical measurements under various climatic conditions. The fiber-optic sensor detected all phenomena at a 100% rate, and the recorded results were compared to the results from a standard seismic station. Both sets of results were recorded simultaneously and agreed significantly, especially in terms of frequency. With regard to time, all tram vehicle axles were detected in individual time records. With regard to frequency, the results detected in the bandwidth generally correlated to rail transport for individual types of tram vehicles.

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Analysis of the detection materials as resonant pads for attaching the measuring arm of the interferometer when sensing mechanical vibrations

Cited by 2 publications

References 5 publications

A Phonocardiographic-Based Fiber-Optic Sensor and Adaptive Filtering System for Noninvasive Continuous Fetal Heart Rate Monitoring

A Phonocardiographic-Based Fiber-Optic Sensor and Adaptive Filtering System for Noninvasive Continuous Fetal Heart Rate Monitoring

Use of Fiber-Optic Sensors for the Detection of the Rail Vehicles and Monitoring of the Rock Mass Dynamic Response Due to Railway Rolling Stock for the Civil Engineering Needs

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