The study explores the potential applications of fiber optic sensors for user verification tasks. An experimental validation of the considered methods for recognizing speech signals obtained from acoustic sensors is conducted. In the experiment, voices of four different speakers were recorded. Each speaker sequentially uttered the same text simultaneously using a capacitor microphone and a fiber optic distributed sensor. To create the dataset, each speaker read three prepared texts. After training the system on the dataset and achieving speech signal recognition with sufficiently high accuracy recorded from the capacitor microphone, attention was turned to addressing the challenge of noise elimination. For this purpose, background noise was separately recorded at the experimental site. The conclusion is drawn regarding the applicability of mel-frequency cepstral coefficients for solving the task of identifying individuals based on the sound signal obtained from the fiber optic sensor with a specified accuracy.
The paper presents a method of underground dielectric optical fiber cable route tracing using a distributed acoustic sensing based on phase-sensitive optical reflectometer. The results of field tests are presented, demonstrating the performance of the method and the ability to determine the location of the cable route with an accuracy of ± 0.2 meters.
The article discusses the use of Distributed Acoustic Sensing technology in locating underground all-dielectric optic cables. DAS uses fiber optic cables to detect acoustic vibrations along the cable's length caused by digging or drilling, allowing for precise identification of the cable's location and path without excavation or other intrusive search methods. DAS provides high-resolution data over long distances, making it more accurate than traditional search methods like geo-radar or GPS markers. The article proposes a localization algorithm for detecting the path of all-dielectric optical cables using DAS technology, based on a combination of approximate and point estimates of cable location. The algorithm is tested on a testing ground of a section of an optical communication line, demonstrating the ability to determine the area of optical cable laying with a radius of up to 5 meters in real-time.
This study aimed to investigate the potential application of distributed fiber-optic acoustic sensors for speech recognition amidst complex audio backgrounds. The experimental measurements were carried out on the mock-up room with a fiberoptic link. The possibility of application the fiber-optic distributed acoustic sensor for localization of sound source and recognition of musical and human speech signals amidst complex audio backgrounds was demonstrated. The signal detected by DAS provides good quality of music composition recognition and clear speech recognition. The difference in spectrum of signals detected by microphone and DAS was analyzed. The signal noise ratios were calculated for test speech signal with different average levels and its influence on the speech recognition was analyzed.
The paper proposes a method for localizing the location of an optical cable based on the analysis of the characteristics of a phase-sensitive reflectometer under external acoustic impact. Approbation of the methodology was carried out using a vibroacoustic monitoring system at a test site built on the territory of the university. The results of measurements of the intensity distribution of the acoustic impact along the length of the optical fiber depending on the location of the impact source are presented. The specific features of the method based on the analysis of amplitude characteristics are determined.
The article considers algorithms for determining the location of a sound source (intruder) using a system of distributed acoustic sensors in two-dimensional and three-dimensional space, in particular, the simple triangulation algorithm and the triangulation algorithm when the sound source is displaced. The algorithms proposed in the paper can be used to build auxiliary security systems to prevent theft of information and valuable property. Modeling of the influence of a source of harmonic acoustic impact on a system of distributed acoustic sensors was carried out, according to the results of which the distance from the optical fiber to the location of the source of harmonic acoustic impact (intruder) could be determined with an error of up to 10-15% or less.
The paper shows the possibilities of searching for a cable laying route, determining the depth of occurrence and localizing damage sites for cables without metal elements. A description of the methods is given and their potential capabilities are considered. New methods of searching for fiber-optic cable lines and determining the locations of their damage are proposed.
Following article presents a simple scheme of an acousto-optic channel and an example of the results of modeling lowspeed data transmission in such channel. Previously obtained experimental data on the amplitude-frequency response of the channel were used in the simulation. The simulation results demonstrate the advantage of using a phase receiver for the considered fiber acousto-optic channels compared to direct detection.
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