Optical Sensor Signal Research Articles

The Method for Obtaining Shot Cloud Time Span and Range Dependence

When studying the behavior of a shot cloud in space, a variety of information and measurement systems can be applied, for example, based on light screens (photoelectronic blocking devices of a small ballistic measuring installation consisting of a linear emitter and an optical sensor based on a photodiode). To study the process of shot cloud movement in space and to assess its parameters (for example, length at a given range from the muzzle) correctly, it is advisable to have a simulation model of the optical sensor signal when the light screen is crossed by a shot cloud. Taking into account previous studies, it is necessary to know the magnitude of the scale parameter in the Rayleigh distribution describing the shot cloud in the direction of firing in time in order to obtain a similar model at some distance from the muzzle. A method that allows obtaining function of dependence of the mentioned scale parameter and the distance from the muzzle and based on real data from several optical sensors of light screens installed on the shooting track is proposed. The example of application the proposed method to obtain similar functions based on the results of processing optical sensor signals obtained in real experiments for cartridges loaded with three different shot types is given. The obtained dependences were approximated by polynomials of the first and second degree using the least squares method, and the error was estimated for various types of cartridges. Based on the obtained results, specific recommendations for the practical application of the developed method are proposed. The estimation of the confidence interval width for the expectation function of the shot cloud time span is performed. The ways of creating advanced signal simulation models from optical sensors of light screens when shooting with shot are outlined.

Amplifying Fibre Optic Sensor Signals with Graphene Oxide-Silver Nanostars

This work presents a straightforward yet impactful method to enhance optical fibre sensor signals by integrating silver nanostars (AgNS) with graphene oxide (GO-AgNS) as a sensing material. AgNS were synthesized successfully via a one-step chemical reduction method using hydroxylamine as a reducing agent. The concentration of hydroxylamine was varied (7.2, 3.6, 1.8, and 0.9) x 10−4 %v/v to optimize AgNS formation, with the longest spike of the nanostar observed at lower hydroxylamine concentrations, as confirmed by transmission electron microscopy (TEM). UV-visible measurements revealed the highest peak absorption for AgNS synthesized using 0.9 x 10−4 %v/v hydroxylamine, 0.05 M sodium hydroxide, 0.8 mM silver nitrate, and 0.045 M sodium citrate, with an average length of 352.62 ± 59.72 nm measured from TEM images. GO was synthesized via a modified Hummer’s method and mixed with AgNS at varying ratios (1:5, 1:10, 1:15, and 1:20) to form GO-AgNS coatings for the fibre optic probe. The GO-AgNS coating at a ratio of 1:5 exhibited the highest light absorption intensity, enhancing optical signal by 218% compared to GO-coated and 174% compared to AgNS-coated fibre optic sensors. These findings demonstrate that embedding AgNS onto the GO matrix structure as a sensing material significantly improves sensor performance, suggesting promising applications for super-sensitive, cost-effective, and rapid detection in fibre optic-based sensors.

Identification of Corrosion-Induced Optical Fiber Acoustic Emission Sensor Signals on the Bottom Plate of Oil Storage Tank Based on Multichannel Attention Mechanism (CBAM)

Identification of Corrosion-Induced Optical Fiber Acoustic Emission Sensor Signals on the Bottom Plate of Oil Storage Tank Based on Multichannel Attention Mechanism (CBAM)

High generalization identification method based on MI-SI distributed optical fiber sensor and video signals

A pattern recognition method for intrusion signals is introduced, leveraging distributed optical fiber sensors and convolutional neural networks. To enhance the model's generalization capabilities, two strategies are employed. Firstly, the sensor structure is refined, incorporating the strengths of both the Sagnac and Michelson interferometers to create a hybrid design with a wide frequency response. Comparative experiments confirm that this exceptional frequency response significantly boosts the model's generalization power. Secondly, to address the limitations of distributed fiber optic sensors, a multimodal approach is proposed, integrating video frame difference and fiber optic pattern recognition. The trained convolutional neural network model exhibits low computational overhead, robust generalization, and practical applicability. When applied to a dataset collected in diverse scenarios not included in the model training, the model achieved a CNR of 0% and a FPR of only 0.26% for the intrusion behavior of climbing fences.

Sensitivity Modal Analysis of Long Reflective Multimode Interferometer for Small Angle Detection and Temperature

This work presents the sensitive modal analysis of a long reflective multimode optical fiber device for angle and temperature. The reflective multimode interference optical fiber device was fabricated by splicing ~40 cm of multimode optical fiber (50/125). This structure provides a random interference reflection spectrum; the wavelength sensitivity analysis indicates that estimating the angle detection is impossible due to the several modes involved. However, by the phase analysis of the Fourier components, it was possible to detect slight angle deflection. Here, three spectral Fourier components were analyzed, and the maximal sensitivity achieved was 1.52 rad/°; the maximal angle variation of the multimode fiber was 3.4°. In addition, the thermal analysis indicates minimal temperature affectation (0.0065 rad/°C). Moreover, it was demonstrated that there is a strong dependence between the sensitivity and the m-order of the modes involved. Considering the fiber optic sensor dimensions and signal analysis, this device is attractive for numerous applications where slight angle detection is needed.

Continuous enantiomeric separation using water-oil-water segmented flow system

The multiphase segmented flow, which consisted of the material, extraction, and recovery phases, was applied to the chiral separation. The use of simultaneous extraction and back-extraction with multiple phases aims to prevent the accumulation of target material in the extraction phase by efficiently removing it in the recovery phase, thereby enabling extraction performance beyond the equilibrium. This study demonstrated the chiral separation of an aqueous racemic amino acid derivative (3,5-dinitrobenzoyl-(R,S)-leucine) with a cinchona alkaloid chiral host. A droplet manipulation system comprising PFA manifolds and valves was utilized to alternately form an acidic material phase slug and a basic recovery phase slug in a 1-octanol oil phase containing the chiral host. Two aqueous phases were collected separately using valves controlled by an optical sensor signal. The manipulation system achieved stable operation across various conditions, including flow rate, residence time, and slug lengths. The enantiomeric excess, which represents the purity of the chirality, could be increased to 50 % through 200 s extraction in a one-step operation.

Hybrid of Free Space Optics Communication and Sensor System Using IWDM Technique

In this work, we designed a novel hybrid of free-space optics (FSO) communication and intensity and wavelength division multiplexing (IWDM)-fiber Bragg grating (FBG) sensor system over a single shared FSO transmission channel for both optical and sensor signal transmission. In the proposed system, we use one broadband light source and one FSO link for both optical and FBG sensor signal transmission, which significantly reduces the cost of system installation and complexity. Besides, the FSO transmission channel is used to solve the problem of geographical constraints when the environment is difficult to install the fiber. In addition, IWDM is one of the best multiplexing technique to increase the sensor number by more than two times the conventional wavelength division multiplexing (WDM) method. Besides, to solve the overlap spectra problem of IWDM based FBG sensor system, we proposed the stacked gated recurrent unit (SGRU) algorithm with the neural network (NN) profile method. The results prove that the proposed SGRU with the NN profile method improves the accuracy of wavelength detection techniques with the Gaussian profile method. Moreover, the FSO transmission channel achieves a clear eye diagram even the system is a hybrid of optical communication and FBG sensors system.

Digital Position and Depth of Interaction Measurement of the PET Detector Through the Signal Ratio

A new detector was designed to improve the spatial resolution of positron emission tomography (PET) and acquire digital coordinates of the detector"s scintillation pixels. In order to solve the spatial resolution deterioration phenomenon due to parallax error occurring outside the field of view (FOV), a method of measuring the depth of interaction was developed, and this was accomplished with the acquisition of digital coordinates. A detector using a 4 × 4 × 2 GAGG scintillator was designed using the DETECT2000 simulation tool to acquire digital coordinates of the scintillation pixels and measure the depth of interaction of the two layers. A gamma-ray reaction was generated in all the scintillation pixels, and the signals were obtained from SiPM pixels in a 4 × 4 array. The 16-channels of optical sensor signals were reduced to signals of 4 channels, and these were calculated as a ratio of each signal. The ratio of the signal was obtained from all the flash pixels, and the position was obtained as digital coordinates by comparing it with the ratio of the signal by the gamma ray response generated at the new position. In order to evaluate the accuracy of acquiring the digital coordinates and the accuracy of the layer where the scintillation pixel in which the scintillator and the gamma ray reacted, a signal was obtained by generating a gamma ray response for the entire length of each scintillation pixel. Gamma-ray reactions were generated at intervals of 0.2 mm from 0.1 mm to 19.9 mm. The obtained signals through these reactions were compared with the signals of each scintillation pixel obtained in advance. Then, the accuracy of measured positions on the X, Y, and Z axes were evaluated. The accuracy of both the X and Y axis showed perfect results, and the accuracy of the Z axis was 91.46 %.

Research on Optical Fiber Sensor Signal Processing Technology Based on Variational Mode Decomposition and Singular Spectrum Analysis

To better apply the phase-sensitive optical time-domain reflectometer (Φ-OTDR) in projects with complex environments, given the problem of the low signal-to-noise ratio of the Φ-OTDR signal, a variational modal decomposition (VMD) is proposed. Signal processing algorithm combined with singular spectrum analysis. First, the equalization optimizer (EO) optimizes the VMD. The VMD decomposes the preprocessed signal into a multi-layer eigenmode function (IMF), selects the IMF component according to the correlation coefficient, and after the SSA noise reduction process, the signal Reconstruction to realize the noise reduction processing of the Φ-OTDR signal. Through experiments, it is proved that the relative mean square error (RMSE) of the method in this paper is lower than that of EO-VMD, and the noise reduction performance is better.

Study of the temporal distribution density of the shot sheaf span to create a simulation model of the optical sensor signal

When studying the space path of a cloud of pellets from a shotgun and evaluating its parameters, it is advisable to have a simulation model of the optical sensor signal when a shot sheaf crosses the light screen. To create such a model, you need to get the relationship between the scale parameter in the Rayleigh distribution and the time span of the shot sheaf. Studies of the temporal distribution density of the shot sheaf span are performed, and graphs of the distribution density of the span for near-real situations are constructed. A linear dependence of the mathematical expectation of the span distribution density on the scale parameter in the Rayleigh distribution is established. A simplified expression is obtained for calculating the mathematical expectation of the time span of the shot sheaf. Statistical modeling confirmed the possibility of the practical use of the proposed formulas, including with a large number of pellets (up to 1000). The dependence of the mathematical expectation of the span on the number of pellets is investigated, its approximation by various functions is carried out, and the approximation errors are estimated. The research conducted allows us to create a simulation model of the optical sensor signal when the shot sheaf crosses the light screen on the basis of empirical data on the real-signal duration (with averaged measurement data for several shots being helpful).

Biophotonic sensors with integrated Si3N4-organic hybrid (SiNOH) lasers for point-of-care diagnostics

Early and efficient disease diagnosis with low-cost point-of-care devices is gaining importance for personalized medicine and public health protection. Within this context, waveguide-(WG)-based optical biosensors on the silicon-nitride (Si3N4) platform represent a particularly promising option, offering highly sensitive detection of indicative biomarkers in multiplexed sensor arrays operated by light in the visible-wavelength range. However, while passive Si3N4-based photonic circuits lend themselves to highly scalable mass production, the integration of low-cost light sources remains a challenge. In this paper, we demonstrate optical biosensors that combine Si3N4 sensor circuits with hybrid on-chip organic lasers. These Si3N4-organic hybrid (SiNOH) lasers rely on a dye-doped cladding material that are deposited on top of a passive WG and that are optically pumped by an external light source. Fabrication of the devices is simple: The underlying Si3N4 WGs are structured in a single lithography step, and the organic gain medium is subsequently applied by dispensing, spin-coating, or ink-jet printing processes. A highly parallel read-out of the optical sensor signals is accomplished with a simple camera. In our proof-of-concept experiment, we demonstrate the viability of the approach by detecting different concentrations of fibrinogen in phosphate-buffered saline solutions with a sensor-length (L-)-related sensitivity of S/L = 0.16 rad nM−1 mm−1. To our knowledge, this is the first demonstration of an integrated optical circuit driven by a co-integrated low-cost organic light source. We expect that the versatility of the device concept, the simple operation principle, and the compatibility with cost-efficient mass production will make the concept a highly attractive option for applications in biophotonics and point-of-care diagnostics.

Development of the remote handling connector for ITER divertor diagnostic system

Diagnostics is a vital system for ITER to collect information during operation. Mineral insulated cables route the electrical and optical diagnostics sensor signals from the divertor area to the diagnostic hall. The diagnostic divertor cassettes are replaced during maintenance, which raises the requirement for a connector between divertor cassette and in-vessel wall. Since it needs to be handled remotely during the installation of the 16 diagnostic divertor cassettes, it is called Remote Handling Connector. Its operating space is limited and its environmental conditions are ultra-high vacuum, baking temperature 350 °C, irradiation and challenging electromagnetic forces. The preliminary design of the Remote Handling Connector is based on the conceptual design of Outboard and Inboard Configurations and is highly impacted by finding an appropriate balance between the external and internal space limitations and system requirements. The design of the system has been an iterative process including several conceptual and mechanical design phases, thermal, magnetic and structural load analysis, risk analysis, and remote handling assessment. Mock-ups were manufactured and tested at Divertor Test Platform 2 and Remote Handling Connector Platform at VTT Tampere Finland. The developed system was evaluated at a preliminary design review meeting organized at the end of 2019. The preliminary design phase provides a baseline for the final design of the Remote Handling Connector system.

Metal-embedded fiber optic sensor packaging and signal demodulation scheme towards high-frequency dynamic measurements in harsh environments

Optical fiber-based sensors are commonly used for industrial monitoring and control processes due to their small size, resistance to electromagnetic interference, and ability to perform a wide variety of high-precision measurements. However, implementing optical fiber sensors in harsh environments is challenging because they are small and fragile. Proper packaging of fiber-optic sensors could extend their use to harsh environments, including at high temperature and under high radiation. Furthermore, conventional fiber optic-based measurement systems often use computationally expensive signal processing algorithms which hinder their use in high-frequency dynamic applications. This work reports on the design of an optical fiber-pressure sensor system based on low-coherence interferometry that uses a metal-embedded optical fiber to provide a robust sensor package. A novel phase demodulation scheme is proposed to extract length changes from the deformation of a thin diaphragm within a Fabry–Pérot cavity to measure pressure. The sensor has been tested to ±100kPa, has a theoretical linear response over a ±270kPa dynamic range (24dB maximum signal-to-noise ratio), and can resolve pressure transients up to 3910kPa/s. Sampling at 100kHz, the present sensor can resolve 2kPa dynamic pressures at frequencies up to 2kHz. Faster transients on the order of tens to hundreds of kHz can theoretically be resolved at the expense of decreasing the maximum resolvable amplitude. A methodology for designing a LCI pressure sensor for a given application is outlined based on the limitations imposed by the Nyquist criterion, the diaphragm's resonant frequency, the LCI optoelectronics, and the phase demodulation scheme. The sensor is the first to implement a low-coherence light source and a Fabry–Pérot interferometer designed to provide real-time high-fidelity pressure measurements using a metal-embedded optical fiber. The demonstrated sensor provides a platform for sensing in harsh conditions such as in nuclear and energy applications.

Computational Neuroscience Applied in Surface Roughness Fiber Optic Sensor.

Computational neuroscience has been widely used in fiber optic sensor signal output. This paper introduces a method for processing the Surface Roughness Fiber Optic Sensor output signals with a radial basis function neural network. The output signal of the sensor and the laser intensity signal as the light source are added to the input of the RBF neural network at the same time, and with the ability of the RBF neural network to approach the non-linear function with arbitrary precision, to achieve the nonlinear compensation of the sensor and reduction of the effect of changes in laser output light intensity at the same time. The Surface Roughness Fiber Optic Sensor adopting this method has low requirements on the stability of the output power of laser, featuring large measuring range, high accuracy, good repeatability, measuring of special surfaces such as minor area, and the bottom surface of holed etc. The measurements were given and various factors that affect the measurement were analyzed and discussed.

Simultaneous Transmission of Photonic Services over One Fiber with an ITU 100 GHz Grid.

The increasing interest in distributed sensors and the decreasing price of optical components have led to leveraging the use of existing fiber in deployments over optical networks and more application possibilities (from seismic activity measurement to perimeter protection and tunnel fire detection). Because of the possibility of data interference in single fibers, dark fibers are used. On the one hand, optical networks are able to transfer popular services, such as streaming and data transmission, and on the other hand, special advanced services such as an accurate time, a stable frequency, and high-power optical sensor signals can be provided. In our work, we address the simultaneous transmission of an accurate time, 100 G data, and a high-power optical sensor based on Phase-sensitive optical time domain reflectometer (-OTDR). The measurement setup consists of the optical fiber G.652 (7 km), G.653 (7 km), and G.655 (10 km) and a combination of G.652D + G.653 (14 km). Moreover, we also provide results for their combination. The services were transferred in single fiber with an ITU 100 GHz channel spacing grid. We performed a set of measurements with an evaluation of the BER value for data transmission affected by a high-power sensor system and accurate time values. The results confirmed our assumptions that 100 GHz spacing is not large enough, especially with the increasing power level of the sensor system. The main aim of the article is to determine whether data are disturbed with normal 100 GHz channel spacing.

Method for optical radiation sensor signal irregularity correction in the computer microscopy system

The paper presents a preliminary study to adjust for the irregularity of the signal space of a sensor of optical radiation in the computer microscopy system. A method for correcting the uneven signal of the optical radiation sensor in computer microscopy systems is proposed based on the results of the research. The proposed approach will allow to correct the results of measurements of the characteristics of objects obtained by light microscopy in combination with computer data processing.

Measuring Heart Rate During Exercise: From Artery Palpation to Monitors and Apps

Abstract The use of technology has increased tremendously, by means of more reliable, smaller, more accessible and specially more user-friendly devices, which provide a wider range of features, and promote significant benefits for the population and health professionals. It is in this context that monitors and apps for heart rate (HR) measurement have emerged. HR is a clinical vital sign of diagnostic and prognostic importance. In response to body movement, HR tends to increase, in a direct relationship with the intensity of exercise. HR was primarily measured by the count of arterial pulse, and recently, HR can be precisely measured by monitors, bracelets and smartphone apps capable to perform real-time measurements and storage of data. This paper aimed to make a brief and updated review on the theme, providing a broader view of advantages and limitations of these resources for HR measurement in exercise. HR monitors and apps use basically two types of technology, optical sensor (photoplethysmography) and electrical signal from the heart. In general, these devices have shown good accuracy in measuring HR and HR variability at rest, but there are differences between brands and models considering the type, mode and intensity of exercise. HR measurements by monitors and smartphone apps are simple, accessible and may help cardiologists in the monitoring of the intensity of aerobic exercise, focusing on health promotion and on primary and secondary prevention of cardiovascular diseases.

Effects of Speed on Tire–Pavement Interaction Noise (Tread-Pattern–Related Noise and Non–Tread-Pattern–Related Noise)

ABSTRACT Tire noise is mainly generated from the interaction between tire and pavement. Different combinations of tire and pavement usually generate noise of different levels and different frequencies. For the same tire and same pavement, the most important factor influencing the noise level is vehicle speed. To provide a detailed description of the effects of speed on the noise generation, the present study investigates the tire noise of nineteen tires of the same size but with different tread patterns. The study includes the standard reference test tire and four other normal patterned tires running on a nonporous asphalt pavement using an on-board sound intensity (OBSI) technique. This OBSI system also has an optical sensor to monitor vehicle speed and to perform order-tracking analysis. The field tests were conducted under different vehicle speed values (72-105 km/h; i.e., 45-65 mph). The effects of speed on the noise spectrum and on the overall noise level have been analyzed. In addition, using the optical sensor signal, the tire noise related to the tire tread pattern has been isolated from noises from all other sources. The effects of speed on the separated signals have also been investigated. It was found that increasing speed increases the frequencies and levels of tread-pattern–related noise component, while for the noise component not related to the tread pattern, increasing speed only increases its amplitude, not its frequency. In addition, the noise generated at the trailing edge of the contact patch is more sensitive to the speed than the one at the leading edge.

Optical Sensor based Chemical Modification as a Porous Cellulose Acetate Film and Its Application for Ethanol Sensor

A new approach to design and construction of an optical ethanol sensor has been developed by immobilizing a direct dye at a porous cellulosic polymer fllm. This sensor was fabricated by binding Nile Red to a cellulose acetate membrane that had previously been subjected to an exhaustive base hydrolysis. The prepared optical ethanol sensor was enhanced by adding pluronic as a porogen in the membrane. The addition of pluronic surfactant into cellulose acetate membrane increased the hydrophilic and porous properties of membrane. Advantageous features of the design include simple and easy of fabrication. Variable affecting sensor performance of dye concentration have been fully evaluated and optimized. The rapid response results from the porous structure of the polymeric support, which minimizes barriers to mass transport. Signal of optical sensor based on reaction of dye nile red over the membrane with ethanol and will produce the purple colored product. Result was obtained that maximum intensity of dye nile red reacted with alcohol is at 630-640 nm. Linear regression equation (r2), limit of detection, and limit of quantitation of membrane with 2% dye was 0.9625, 0.29%, and 0.97%. Performance of optical sensor was also evaluated through methanol, ethanol and propanol. This study was purposed to measure the polarity and selectivity of optic sensor toward the alcohol derivatives. Fluorescence intensity of optic sensor membrane for methanol 5%, ethanol 5% and propanol 5% was 15113.56, 16573.75 and 18495.97 respectively.

Experimental research on negative pressure wave signal of optical fiber and electronic sensor

Negative pressure wave technique is an effective method for pipeline leak detection. In order to obtain more accurate inflection point information of negative pressure wave and improve signal to noise ratio, experiments using 102.8 meters pipeline experimental platform, according to the negative pressure wave signal captured by the sensors, the response time, static stability and anti-electromagnetic interference of the optical fiber sensor and the traditional electronic pressure sensor are analyzed. Experimental results show that from the leakage of negative pressure wave signal acquisition to the pressure signal restore stability, optical fiber sensor takes about 30 ms, which is far better than the electronic sensor 500 ms. In the static stability experiment, the pressure signal output of optical fiber sensor is stable, and the pressure fluctuation range is ± 0.001 MPa, which is far less than the electronic sensor ± 0.006 MPa. Comprehensive evaluation analysis shows that the optical fiber sensor has good stability and anti-electromagnetic interference performance, and has wide application prospect in the fields of pipeline leakage monitoring, energy and chemical industry.