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Journal articles on the topic 'Contactless position measurement'
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1
Edwards, J. D. "Contactless measurement of the secondary position in linear reluctance motors." IEE Proceedings - Electric Power Applications 142, no. 6 (1995): 355. http://dx.doi.org/10.1049/ip-epa:19952227.
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Nguyen, Trung Tran, Arvid Amthor, and Christoph Ament. "Algorithm for a high precision contactless measurement system." ACTA IMEKO 2, no. 2 (January 15, 2014): 3. http://dx.doi.org/10.21014/acta_imeko.v2i2.82.
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This paper presents a Monte Carlo simulation of the self-calibration method for the multi laser tracker system (MLTS) which can track a retroreflector mounted on a kinematical system (e.g. positioning stage, robot manipulator etc.). Four laser trackers build up the MLTS. In the first part of the study the required algorithms enabling the MLTS to measure the position of the retroreflector are presented. The algorithms include the localization of the retroreflector, the communication between the laser trackers and the tracking controller as well as the calculation of the Tool Centre Point (TCP) position. In the second part of this study a deeper analysis of the self-calibration algorithm is carried out. A Monte Carlo simulation shows that the quality of the parameter estimation highly depends on the optimal arrangement of the MTLS.
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Pan, Hai Bin, Lian He Yu, Guang Gui Cheng, and Hui Juan Fan. "Contactless Measurement of the Strain in Microcantilever Based on Position Sensitive Detector." Advanced Materials Research 204-210 (February 2011): 969–72. http://dx.doi.org/10.4028/www.scientific.net/amr.204-210.969.
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We report on a novel method for measurement of the strain in microcantilever, and a contactless measurement system for strain in microcantilever is designed and implemented based on position sensitive detector (PSD) using optical lever method. To verify the validity and accuracy of the results from measurement, a finite element model of the uniform strength microcantilever has been developed to simulate mechanical behavior in microcantilever based on finite element method (FEM). The results show that results obtained from FEM and measurement based on PSD show excellent agreement. This work has provided a novel and more effective method for measurement of the strain in microcantilever.
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Ferrari, V., A. Ghisla, D. Marioli, and A. Taroni. "Array of pPZTpyroelectric thick-film sensors for contactless measurement of XY position." IEEE Sensors Journal 3, no. 2 (April 2003): 212–17. http://dx.doi.org/10.1109/jsen.2002.807586.
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Aschenbrenner, Bernhard, and Bernhard G. Zagar. "Contactless high frequency inductive position sensor with DSP read out electronics utilizing band-pass sampling." ACTA IMEKO 3, no. 3 (September 23, 2014): 50. http://dx.doi.org/10.21014/acta_imeko.v3i3.76.
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This paper presents a precise, reliable, low cost and contactless inductive absolute position measurement system for rough industrial environments. It offers a high inherent resolution (0.04 % of antenna length), and measures absolute position over a relative wide measurement range. The main property for this kind of sensor is its good immunity to external noise and target misalignment off the measurement axis. The measurement range and the precision are extended by adding additional and finer pitched receive coils. This sensor works on similar principles as resolvers but consists of a rectangular antenna PCB, a small moveable passive LC resonant circuit and a signal processing unit. Furthermore, the used read out electronics utilizes under-sampling to demodulate the sensor output signals and the corresponding position is estimated from a lookup table (LUT) implemented on a digital signal processor (DSP) to avoid singularities in the inverse tangent and cotangent calculation. Moreover, the mechanical transducer arrangement, the signal condition electronics design and measurement results of the transmitter to receiver signal coupling and relative position error will be presented.
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Lumetti, Stefano, Perla Malagò, Dietmar Spitzer, Sigmund Zaruba, and Michael Ortner. "Computationally Efficient Magnetic Position System Calibration." Engineering Proceedings 2, no. 1 (November 14, 2020): 72. http://dx.doi.org/10.3390/ecsa-7-08219.
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Properties such as high resolution, contactless (and thus wear-free) measurement, low power consumption, robustness against temperature and contamination as well as low cost make magnetic position and orientation systems appealing for a large number of industrial applications. Nevertheless, one major practical challenge is their sensitivity to fabrication tolerances. In this work, we propose a novel method for magnetic position system calibration based on the analytical computation of the magnetic field and on the application of an evolutionary optimization algorithm. This scheme enables the calibration of more than 10 degrees of freedom within a few seconds on standard quad-core ×86 processors, and is demonstrated by calibrating a highly cost-efficient 3D-printed 3-axis magnetic joystick.
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Su, Jian Dong, Xiu Sheng Duan, and Jing Xiao. "Vision Measurement for the Pose of Cannon Barrel." Applied Mechanics and Materials 423-426 (September 2013): 2530–35. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.2530.
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The pose measurement of cannon barrel (vertical angle and azimuth angle) is a difficulty and emphasis in the precision analysis of SPAAG fire control system. To solve this problem, this paper presents a contactless measuring method based on computer vision. Before measurement, fix a checked planar faceplate on the cannon barrel as a marker. Firstly, get the coordinate of X corner points using Harris Corner Detection Algorithm to calibrate the camera, and chalk up the cameras intrinsic parameters based on Extended Kalman Filter. Secondly, get the corner points from the image of test position, then calculate the extrinsic parameter matrix of the corresponding position combining with LSE algorithm. Finally, according to the motion model of cannon barrel and the position relative to the marker, derive the constraint equations between extrinsic parameter and vertical angle and azimuth angle, then figure out the two angles. Experiment validate the maneuverability and veracity of this method, and the results indicate that the measuring precision of this method is less than 1mil.
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Wang, Jingang, Xiaojun Yan, Lu Zhong, and Xiaobao Zhu. "Simulation and Test of a Contactless Voltage Measurement Method for Overhead Lines Based on Reconstruction of Integral Node Parameters." Sensors 20, no. 1 (December 31, 2019): 246. http://dx.doi.org/10.3390/s20010246.
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To improve the stability and adaptability of the voltage measurement based on the E-field (electric field) integral method, in this paper we introduce a new method for the contactless voltage measurement of the overhead lines. The method adopts the node parameter reconstruction technology, which is based on the Gauss–Chebyshev algorithm. In order to achieve high-quality E-field detection at the reconstructed node position, we designed a novel D-dot sensor with parallel distributed electrodes. A Maxwell simulation model of multi-level voltages of the overhead lines was carried out to determine a comprehensive criterion of the reconstruction factors. The simulation employed a three-phase overhead line experiment platform to calculate and measure the distribution and the changing trend of the E-field. The deviations of the voltage measurement were reduced at a significantly low level within 0.4%. The result of the simulation demonstrates that the method optimizes sensor distribution by reconstructing node parameters, which enables the system to have high accuracy and reliability on the contactless voltage measurement of the overhead lines.
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Huber, Samuel, Jan-Willem Burssens, Nicolas Dupré, Olivier Dubrulle, Yves Bidaux, Gael Close, and Christian Schott. "A Gradiometric Magnetic Sensor System for Stray-Field-Immune Rotary Position Sensing in Harsh Environment." Proceedings 2, no. 13 (December 13, 2018): 809. http://dx.doi.org/10.3390/proceedings2130809.
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Contactless magnetic position sensors are used in countless industrial and automotive applications. However, as a consequence of the electrification trend the sensors can be exposed to parasitic magnetic stray fields, and their desired robustness may be compromised. In this paper we publish for the first time how this challenge is addressed and constructively solved using a complete paradigm change leaving conventional magnetic field measurement behind and entering into the realm of magnetic field gradient measurement. Our novel sensor system consists of an integrated Hall sensor realized in 0.18 μm CMOS technology with magnetic concentrators and a four-pole permanent magnet. The intrinsic angular accuracy was assessed comparing the rotary position of the permanent magnet with the sensor output showing angle errors below 0.3°. Additional end-of-line calibration can be applied using built-in memory and processing capability to further increase the accuracy. Finally, we demonstrate the immunity against stray fields of 4000 A/m which led to errors below 0.1°, corresponding to 0.06% of the sensors fullscale angular range. In conclusion, this novel sensor system offers a compact and flexible solution for stray-field immune rotary position measurement in harsh environment.
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Schmid-Schirling, Tobias, Lea Kraft, and Daniel Carl. "Laser scanning–based straightness measurement of precision bright steel rods at one point." International Journal of Advanced Manufacturing Technology 116, no. 7-8 (July 9, 2021): 2511–19. http://dx.doi.org/10.1007/s00170-021-07468-7.
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AbstractIn industrial manufacturing of bright steel rods, one important quality factor is the straightness or straightness deviation. Depending on the application, deviations of less than 0.1 mm per meter rod length are desired and can be reached with state-of-the-art manufacturing equipment. Such high-quality requirements can only be guaranteed with continuous quality control. Manual straightness measurements conducted offline using a dial gauge provide accurate results on single positions of the rod. We propose a contactless, optical measurement technique based on laser scanning which has the potential to be used inline during production to inspect all rods over the entire length. Only for calibration of the system the rod needs to be turned around its axis. For the measurement of straightness deviation, it is not required to turn the rod. The method is based on evaluating the intensity signal of the reflected laser radiation against the scan angle. It is shown that in combination with an accurate calibration, this signal can be used to determine the rod’s deviation from a straight rod. We explain the measurement and calibration principle as well as data evaluation. We present the experimental setup and first measurement results on a single position on several samples. For a homogeneous sample surface and neglecting laser drift, accuracy and precision were determined to be in the range of 10–20 μm. We discuss the working principle of a potential inline system.
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Barbot, Nicolas, and Etienne Perret. "A Chipless RFID Method of 2D Localization Based on Phase Acquisition." Journal of Sensors 2018 (July 19, 2018): 1–6. http://dx.doi.org/10.1155/2018/7484265.
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This paper explores the performance of object localization using chipless tags. We show that it is possible to localize a tag (or an object attached to it) by measuring the phase offset between a known position and the position to estimate. This method provides better accuracy compared to classical ones based on received signal strength indicator (RSSI) or round-trip time of flight. We show that submillimeter precision for distance measurement and an error of less than 4 mm for localization can be achieved. These results point the way toward new kinds of sensors and user interfaces using chipless tags which can be contactless and 3D. This new possibility is in addition to the identification functionality which is inherent to the use of chipless tags.
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Gleichauf, Daniel, Michael Sorg, and Andreas Fischer. "Contactless Localization of Premature Laminar–Turbulent Flow Transitions on Wind Turbine Rotor Blades in Operation." Applied Sciences 10, no. 18 (September 19, 2020): 6552. http://dx.doi.org/10.3390/app10186552.
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Thermographic flow visualization enables a noninvasive detection of the laminar–turbulent flow transition and allows a measurement of the impact of surface erosion and contamination due to insects, rain, dust, or hail by quantifying the amount of laminar flow reduction. The state-of-the-art image processing is designed to localize the natural flow transition as occurring on an undisturbed blade surface by use of a one-dimensional gradient evaluation. However, the occurrence of premature flow transitions leads to a high measurement uncertainty of the localized transition line or to a completely missed flow transition detection. For this reason, regions with turbulent flow are incorrectly assigned to the laminar flow region, which leads to a systematic deviation in the subsequent quantification of the spatial distribution of the boundary layer flow regimes. Therefore, a novel image processing method for the localization of the laminar–turbulent flow transition is introduced, which provides a reduced measurement uncertainty for sections with premature flow transitions. By the use of a two-dimensional image evaluation, local maximal temperature gradients are identified in order to locate the flow transition with a reduced uncertainty compared to the state-of-the-art method. The transition position can be used to quantify the reduction of the laminar flow regime surface area due to occurrences of premature flow transitions in order to measure the influence of surface contamination on the boundary layer flow. The image processing is applied to the thermographic measurement on a wind turbine of the type GE 1.5 sl in operation. In 11 blade segments with occurring premature flow transitions and a high enough contrast of the developed turbulence wedge, the introduced evaluation was able to locate the flow transition line correctly. The laminar flow reduction based on the evaluated flow transition position located with a significantly reduced systematic deviation amounts to 22% for the given measurement and can be used to estimate the reduction of the aerodynamic lift. Therefore, the image processing method introduced allows a more accurate estimation of the effects of real environmental conditions on the efficiency of wind turbines in operation.
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Guo, Zhe, Yang Bai, Lin Yi, Ji Feng Guo, and Jian Wang. "A Novel Method on Real-Time Measurement of 2-DOF Motions of Spherical Ultrasonic Motor." Applied Mechanics and Materials 416-417 (September 2013): 1080–85. http://dx.doi.org/10.4028/www.scientific.net/amm.416-417.1080.
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Spherical ultrasonic motor (SUSM) is utilized primarily in the assembly sectors, precision machining and active tracking devices. The controllability and accuracy of the SUSM are much concerned in those practical uses. So the sensors which measure the motion of the stator are usually used to build up a closed loop control system. These sensors can detect the position and speed of the ball stator. However, the traditional contact positional detection device which contains photoelectric encoders has the disadvantages of low measuring precision. A novel contactless method which based on an optical sensor, is introduced in the paper. A further illustration including principles of the method, the model of 2-DOF motion of the spherical ultrasonic motor rotor, a set of experiment test-bed to verify the feasibility of the method are presented in the article. The experiment turns out an expectant result and shows the method feasible and significant for application.
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Erdélyi, Ján. "Automated point clouds processing for deformation monitoring." Geoinformatics FCE CTU 14, no. 2 (December 8, 2015): 47–54. http://dx.doi.org/10.14311/gi.14.2.5.
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<p>The weather conditions and the operation load are causing changes in the spatial position and in the shape of engineering constructions, which affects their static and dynamic function and reliability. Because these facts, geodetic measurements are integral parts of engineering structures diagnosis.</p><p>The advantage of terrestrial laser scanning (TLS) over conventional surveying methods is the efficiency of spatial data acquisition. TLS allows contactless determining the spatial coordinates of points lying on the surface on the measured object. The scan rate of current scanners (up to 1 million of points/s) allows significant reduction of time, necessary for the measurement; respectively increase the quantity of obtained information about the measured object. To increase the accuracy of results, chosen parts of the monitored construction can be approximated by single geometric entities using regression. In this case the position of measured point is calculated from tens or hundreds of scanned points.</p><p>This paper presents the possibility of deformation monitoring of engineering structures using the technology of TLS. For automated data processing was developed an application based on Matlab®, Displacement_TLS. The operation mode, the basic parts of this application and the calculation of displacements are described.</p>
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Bai, Jiao, Xinghui Li, Xiaohao Wang, Qian Zhou, and Kai Ni. "Chromatic Confocal Displacement Sensor with Optimized Dispersion Probe and Modified Centroid Peak Extraction Algorithm." Sensors 19, no. 16 (August 18, 2019): 3592. http://dx.doi.org/10.3390/s19163592.
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Chromatic confocal technology (CCT) is one of the most promising methods for the contactless and accurate measurement of structure profiles. Based on the principles of chromatic dispersion and confocal theory, a dispersion probe is proposed and optimized with several commercial and cheap refractive index lenses. The probe provides 0.3× magnification and a dispersion range of 400 μm with a commercial LED source with an effective bandwidth of ca. 450–623 nm. Since the noise fluctuation can affect the extraction stability of the focal wavelength, a modification to the centroid peak extraction algorithm is proposed in this paper, where several virtual pixels are interpolated among the real pixels of the spectrometer before thresholding. In addition, a series of experiments were carried out to test the system’s displacement measurement performance. The results clearly show that stability is improved by the modified algorithm, and the calibration repeatability is ±0.3 μm in the full measurement range with a linear stage. The standard deviation at the fixed position has an optimal value of 0.009 μm. The section profile of a Fresnel lens is measured by the CCT system to demonstrate its high feasibility and efficiency.
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Kurth, Katharina H., and Dietmar Drummer. "Effect of the variation of the gating system on the magnetic properties of injection molded pole-oriented rings." Journal of Polymer Engineering 37, no. 6 (July 26, 2017): 537–46. http://dx.doi.org/10.1515/polyeng-2016-0306.
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Abstract The demand for contactless and wear-free sensor systems for the measurement of different physical values, such as angle, position, or speed has increased over the past years and opened up new application areas for magnetically sensitive sensors. Polymer bonded magnets can be used as signal transmitters in these sensor applications. In general, a high precision and good repeatability of the magnetic field is required, whereas in particular, a high peak flux density and accurate pole length of each pole is demanded for precise measurement. These polymer bonded magnets can be produced economically using the injection molding process with an integrated magnetization of the particles, such that a second magnetization step is unnecessary. This article addresses the influences of the gating system on the magnetic properties of multipolar bonded rings. Further, the particle orientation as well as filler content at different locations, and along the pathway are investigated. It was evaluated that the gating system significantly influences the pole length accuracy, as well as the peak flux density. However, differences in the filler orientation and content cannot be analyzed quantitatively.
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Zani, Veronica, Danilo Pedron, Roberto Pilot, and Raffaella Signorini. "Biocompatible Temperature Nanosensors Based on Titanium Dioxide." Proceedings 60, no. 1 (November 2, 2020): 16. http://dx.doi.org/10.3390/iecb2020-07086.
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The measurement of temperature is of fundamental importance in a huge scale of applications, from nanomedicine, where the early detection of tumorous cells is an essential requirement, to microelectronics and microcircuits. Optical sensors with a micro/nano-spatial resolution can be used for temperature determination within a biological frame. Within this context, Raman spectroscopy is particularly interesting: the inelastic scattering of light has the advantage of a contactless measurement and exploits the temperature-dependence of intensities in the spectrum by observing the intensity ratio of anti-Stokes and Stokes signals. Titanium dioxide can be regarded as a potential optical material for temperature detection in biological samples, thanks to its high biocompatibility, already demonstrated in literature, and to its strong Raman scattering signal. The aim of the present work is the realization of biocompatible optical thermometers, with a sub-micrometric spatial resolution, made of titanium dioxide. Raman measurements have been performed on anatase powder using 514.5, 568.2 and 647.1 nm excitation lines of the CW Ar/Kr ion laser. The laser beam was focalized through a microscope on the sample, kept at defined temperature using a temperature controller. The Stokes and anti-Stokes scattered light was analyzed through a triple monochromator and detected by a liquid nitrogen-cooled CCD camera. Raw data were analyzed with Matlab and Raman spectrum parameters—such as area, intensity, frequency position and width of the peak—were calculated using a Lorentz fitting curve. Preliminary results showed that good reliable temperatures can be obtained.
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Andò, Bruno, Salvatore Baglio, Ruben Crispino, and Vincenzo Marletta. "Polymeric Transducers: An Inkjet Printed B-Field Sensor with Resistive Readout Strategy." Sensors 19, no. 23 (December 3, 2019): 5318. http://dx.doi.org/10.3390/s19235318.
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Magnetic field sensors are successfully used in numerous application contexts such as position sensing, speed detection, current detection, contactless switches, vehicle detection, and electronic compasses. In this paper, an inkjet printed magnetic sensor, based on the magneto-mechanical sensing principle, is presented together with a physical model describing its physical behavior and experimental results. The main novelties of the proposed solution consist of its low cost, rapid prototyping (printing and drying time), disposability, and in the use of a commercial low-cost printer. A measurement survey has been carried out by investigating magnetic fields belonging to the range 0–27 mT and for different values of the excitation current forced in the actuation coil. Experimental results demonstrate the suitability of both the proposed sensing strategy and model developed. In particular, in the case of an excitation current of 100 mA, the device responsivity and resolution are 3700 µε/T and 0.458 mT, respectively.
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Buyong, Muhamad Ramdzan, Farhad Larki, Muhamad Ikhmal Hakimi Zainal, Abdelaziz Yousif Ahmed Almahi, Ahmad Ghadafi Ismail, Azrul Azlan Hamzah, Aminuddin Ahmad Kayani Kayani, Céline Elie Caille, and Burhanuddin Yeop Majlis. "Implementation of capacitance as simultaneous sensing and actuating tool in tapered microelectrode arrays for dielectrophoresis-on-a-chip application." Microelectronics International 37, no. 4 (September 21, 2020): 215–24. http://dx.doi.org/10.1108/mi-04-2020-0023.
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Purpose This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator device. The application of DEP-on-a-chip (DOC) can be used to evaluate and correlate the capacitive sensing measurement at an actual position and end station of liquid suspended targeted particles by DEP force actuator manipulation. Design/methodology/approach The capability of both, sensing and manipulation was analysed based on capacitance changes corresponding to the particle positioning and stationing of the targeted particles at regions of interest. The mechanisms of DEP sensor and actuator, designed in DOC applications were energized by electric field of tapered DEP microelectrodes. The actual DEP forces behaviour has been also studied via quantitative analysis of capacitance measurement value and its correlation with qualitative analysis of positioning and stationing of targeted particles. Findings The significance of the present work is the ability of using tapered DEP microelectrodes in a closed mode system to simultaneously sense and vary the magnitude of manipulation. Originality/value The integration of DOC platform for contactless electrical-driven with selective detection and rapid manipulation can provide better efficiency in in situ selective biosensors or bio-detection and rapid bio-manipulation for DOC diagnostic and prognostic devices.
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Al-Naji, Ali, Ghaidaa A. Khalid, Jinan F. Mahdi, and Javaan Chahl. "Non-Contact SpO2 Prediction System Based on a Digital Camera." Applied Sciences 11, no. 9 (May 7, 2021): 4255. http://dx.doi.org/10.3390/app11094255.
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Patients with the COVID-19 condition require frequent and accurate blood oxygen saturation (SpO2) monitoring. The existing pulse oximeters, however, require contact-based measurement using clips or otherwise fixed sensor units or need dedicated hardware which may cause inconvenience and involve additional appointments with the patient. This study proposes a computer vision-based system using a digital camera to measure SpO2 on the basis of the imaging photoplethysmography (iPPG) signal extracted from the human’s forehead without the need for restricting the subject or physical contact. The proposed camera-based system decomposes the iPPG obtained from the red and green channels into different signals with different frequencies using a signal decomposition technique based on a complete Ensemble Empirical Mode Decomposition (EEMD) technique and Independent Component Analysis (ICA) technique to obtain the optical properties from these wavelengths and frequency channels. The proposed system is convenient, contactless, safe and cost-effective. The preliminary results for 70 videos obtained from 14 subjects of different ages and with different skin tones showed that the red and green wavelengths could be used to estimate SpO2 with good agreement and low error ratio compared to the gold standard of pulse oximetry (SA210) with a fixed measurement position.
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Лопатина, В. В., and В. Г. Сенченко. "Methodic of measuring of geometric displacements of a moving object." MORSKIE INTELLEKTUAL`NYE TEHNOLOGII), no. 4(50) (December 17, 2020): 62–66. http://dx.doi.org/10.37220/mit.2020.50.4.098.
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Одной из задач компьютерного зрения является задача обработки изображений для бесконтактного измерения физических величин. Например, бесконтактное высокоточное измерение продольного, поперечного и вертикального смещения подвижного объекта, учитывая особенности его размера, формы, скорости маневрирования, скорости движения. Предлагаемая работа содержит описание подхода к решению таких задач. В работе предложена методика проведения бесконтактных измерений геометрических перемещений подвижного объекта относительно стационарной базы. Применение методики проиллюстрировано на алгоритме обработки серии последовательных кадров приведённом в тексте работы. В тексте кратко описан принцип действия лазерно-оптического измерителя, для которого разработана методика. Описаны методы вычисления продольного, поперечного и вертикального смещения. Порядок использования лазерно-оптического измерителя и применение методики показаны на примере решения задачи высокоточного позиционирования корпуса морского транспортного судна относительно причала при выполнении операции швартовки и погрузо-разгрузочных работ. Результаты работы могут быть использованы при создании высокоточных систем позиционирования и высокоточных систем проводки не только для водного, но и для других видов транспорта (автодорожный, воздушный и железнодорожный). Такие системы решают задачи стабилизация положения подвижных объектов в различных транспортных системах, а также контроль положения. One of the tasks of computer vision is the task of image processing for the contactless measurement of physical quantities. For example, non-contact high-precision measurement of the longitudinal, transverse and vertical displacements of a moving object, taking into account the peculiarities of its size, shape, speed of maneuvering, speed of movement. The proposed work contains a description of an approach to solve such problems. The article proposes a methodic for non-contact measurements of geometric displacements of a moving object relative to a stationary base. The application of the methodic is illustrated on the algorithm for processing a series of sequential frames given in the text of the work. The text briefly describes the principle of operation of the laser-optical meter, for which the methodic has been developed. Methods for calculating the longitudinal, transverse and vertical displacements are described. The order of using the laser-optical meter and the application of the methodic are shown by the example of solving the problem of high-precision positioning of the hull of a sea transport vessel relative to the berth during mooring and loading and unloading operations. The results of the work can be used to create high-precision positioning systems and high-precision guidance systems not only for water transport, but also for other types of transport (road, air and rail). Such systems solve the problem of stabilizing the position of moving objects in various transport systems, as well as position control.
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Marčiš, Marián, Marek Fraštia, and Tomáš Augustín. "Measurement of Flat Slab Deformations by the Multi-Image Photogrammetry Method." Slovak Journal of Civil Engineering 25, no. 4 (December 20, 2017): 19–25. http://dx.doi.org/10.1515/sjce-2017-0019.
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Abstract The use of photogrammetry during load tests of building components is a common practise all over the world. It is very effective thanks to its contactless approach, 3D measurement, fast data collection, and partial or full automation of image processing; it can deliver very accurate results. Multi-image convergent photogrammetry supported by artificial coded targets is the most accurate photogrammetric method when the targets are detected in an image with a higher degree of accuracy than a 0.1 pixel. It is possible to achieve an accuracy of 0.03 mm for all the points measured on the object observed if the camera is close enough to the object, and the positions of the camera and the number of shots are precisely planned. This contribution deals with the design of a special hanging frame for a DSLR camera used during the photogrammetric measurement of the deformation of flat concrete slab. The results of the photogrammetric measurements are compared to the results from traditional contact measurement techniques during load tests.
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NEZU, Kazuyoshi, Itaru MATSUMURA, Mitsuo ABOSHI, Makoto NIWAKAWA, Takuro KAWABATA, and Seiji TABAYASHI. "Contactless Measuring Method of Overhead Contact Line Positions by Stereo Image Measurement and Laser Distance Measurement." Quarterly Report of RTRI 56, no. 3 (2015): 181–86. http://dx.doi.org/10.2219/rtriqr.56.181.
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Malinowski, Pawel, Tomasz Wandowski, and Wieslaw Ostachowicz. "Guided Waves for Aircraft Panel Monitoring." Key Engineering Materials 558 (June 2013): 107–15. http://dx.doi.org/10.4028/www.scientific.net/kem.558.107.
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The reported research concerns experimental investigation toward the monitoring of an aircraft panel. Guided wave propagation phenomena were used to obtain information about the state of the monitored structure. A curved aluminium panel with rivets was investigated. Piezoelectric transducer was used to excite guided waves in chosen structural element. The generated signal was amplified before applying it to the transducer in order to ensure measurable amplitude of excited guided waves. Measurement of the wave field was realized using laser scanning vibrometer that registered the velocity responses at a points belonging to a defined mesh. This contactless measurement technique allowed to investigate phenomena related to wave propagation in the aircraft panel. In the first stage, due to high complexity of the element, baseline measurements were taken. Next, a discontinuity (additional mass) was introduced on the panel surface and the measurements were repeated. Signal processing methods for features extraction from signals were proposed. These features were applied in order to detect and localize the presence anomalies in the investigated panel. The signal processing was conducted in MATLAB with the procedures developed by the authors. The used measurement technology (vibrometer) allowed to register whole wavefield of the propagating guided waves. This allowed to visualize the interaction of the waves with rivets. After introducing the discontinuity on the panel surface wave interaction with it was investigated. Two positions of the additional mass were considered. One just before the riveted stiffener and second after the stiffener. Because of this the influence of the stiffener on the damage detection abilities could be investigated. It can be concluded that the guided wave can be used for monitoring of such complex structures. The vibrometer measurements allowed learn about the guided wave propagation phenomena and perform successful damage localization.
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Zani, Veronica, Danilo Pedron, Roberto Pilot, and Raffaella Signorini. "Contactless Temperature Sensing at the Microscale Based on Titanium Dioxide Raman Thermometry." Biosensors 11, no. 4 (April 2, 2021): 102. http://dx.doi.org/10.3390/bios11040102.
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The determination of local temperature at the nanoscale is a key point to govern physical, chemical and biological processes, strongly influenced by temperature. Since a wide range of applications, from nanomedicine to nano- or micro-electronics, requires a precise determination of the local temperature, significant efforts have to be devoted to nanothermometry. The identification of efficient materials and the implementation of detection techniques are still a hot topic in nanothermometry. Many strategies have been already investigated and applied to real cases, but there is an urgent need to develop new protocols allowing for accurate and sensitive temperature determination. The focus of this work is the investigation of efficient optical thermometers, with potential applications in the biological field. Among the different optical techniques, Raman spectroscopy is currently emerging as a very interesting tool. Its main advantages rely on the possibility of carrying out non-destructive and non-contact measurements with high spatial resolution, reaching even the nanoscale. Temperature variations can be determined by following the changes in intensity, frequency position and width of one or more bands. Concerning the materials, Titanium dioxide has been chosen as Raman active material because of its intense cross-section and its biocompatibility, as already demonstrated in literature. Raman measurements have been performed on commercial anatase powder, with a crystallite dimension of hundreds of nm, using 488.0, 514.5, 568.2 and 647.1 nm excitation lines of the CW Ar+/Kr+ ion laser. The laser beam was focalized through a microscope on the sample, kept at defined temperature using a temperature controller, and the temperature was varied in the range of 283–323 K. The Stokes and anti-Stokes scattered light was analyzed through a triple monochromator and detected by a liquid nitrogen-cooled CCD camera. Raw data have been analyzed with Matlab, and Raman spectrum parameters—such as area, intensity, frequency position and width of the peak—have been calculated using a Lorentz fitting curve. Results obtained, calculating the anti-Stokes/Stokes area ratio, demonstrate that the Raman modes of anatase, in particular the Eg one at 143 cm−1, are excellent candidates for the local temperature detection in the visible range.
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Rodrigues, Maykmiller Carvalho, Francisco Carlos Gomes, Roberto Alves Braga Jr., Fernando Pujaico Rivera, Ricardo Rodrigues Magalhães, and Jéssica Assaid Martins Rodrigues. "THE USE OF PARTICLE IMAGE VELOCIMETRY FOR DISPLACEMENT MEASUREMENTS IN STEEL COLUMNS SUBJECTED TO BUCKLING." Theoretical and Applied Engineering 2, no. 2 (June 25, 2018): 1–6. http://dx.doi.org/10.31422/taae.v2i2.5.
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Displacements in structural columns have many challenges regarding to monitoring since it is a complex phenomenon. The monitoring of steel column subjected to buckling is one challenge in order to identify its structural behavior based on displacement measurements. In some cases, this effect is studied under steel rectangular column subjected to axial compressive loads. It is necessary in order to quantify the horizontal column deformation by using optical techniques based on displacements from images to evaluate its structural behavior. This paper is aimed to apply the Particle Image Velocimetry (PIV) technique as a robust and cheap optical method on buckling study of columns as a contactless measurement technique compared to Finite Element Method (FEM). Experiments using rectangular bar samples were used to evaluate the behavior of columns under axial compressive load causing the buckling effect. In order to quantify displacements, PIV technique was applied based on pre-defined positions of the points in the images and the column displacements were measured and compared to FEM. Results indicated displacements difference around 1.08% between PIV and FEM, providing that PIV technique can be used to quantify column displacements in a plane when compared to FEM results. This allows PIV applications for any structures monitoring such as building, bridges and silos.
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Zhang, Hong, Dong-ze Cui, Ying-jie Jiao, and Xi Chen. "Analysis on Vibration Characteristics of Air Film Damping with Open Boundaries." Mathematical Problems in Engineering 2019 (April 2, 2019): 1–10. http://dx.doi.org/10.1155/2019/1414872.
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Air film damping (AFD) has been a research focus for the fatigue damage suppression problem of aeroengine blade decades ago; however significant progress has not been made in the past decade. In this paper, we present a theoretical model and experimental analysis about this technology. The dissipation mechanism of the AFD is established by assumption that the viscous gas inside the thin air film is Poiseuille flow and the energy dissipation equation of AFD with open boundaries is deduced and evaluated. Blade simulated testing specimens are designed. The vibration measurements are performed by RC-3000 vibration exciter and detected by applying the contactless laser vibrometer system. The theoretical results consist with the experimental results, and both show that AFD appears promising performance in vibration suppression. We also present how the structure parameters, such as installation position, air film length and thickness, and thin skin thickness, influence the vibration suppression effect.
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Wu, Yongkang, Baoping Lu, Wei Zhang, Yandan Jiang, Baoliang Wang, and Zhiyao Huang. "A New Logging-While-Drilling Method for Resistivity Measurement in Oil-Based Mud." Sensors 20, no. 4 (February 16, 2020): 1075. http://dx.doi.org/10.3390/s20041075.
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Resistivity logging is an important technique for identifying and estimating reservoirs. Oil-based mud (OBM) can improve drilling efficiency and decrease operation risks, and has been widely used in the well logging field. However, the non-conductive OBM makes the traditional logging-while-drilling (LWD) method with low frequency ineffective. In this work, a new oil-based LWD method is proposed by combining the capacitively coupled contactless conductivity detection (C4D) technique and the inductive coupling principle. The C4D technique is to overcome the electrical insulation problem of the OBM and construct an effective alternating current (AC) measurement path. Based on the inductive coupling principle, an induced voltage can be formed to be the indirect excitation voltage of the AC measurement path. Based on the proposed method, a corresponding logging instrument is developed. Numerical simulation was carried out and results show that the logging instrument has good measurement accuracy, deep detection depth and high vertical resolution. Practical experiments were also carried out, including the resistance box experiment and the well logging experiment. The results of the resistance box experiment show that the logging instrument has good resistance measurement accuracy. Lastly, the results of the well logging experiment indicate that the logging instrument can accurately reflect the positions of different patterns on the wellbore of the experimental well. Both numerical simulation and practical experiments verify the feasibility and effectiveness of the new method.
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Tan, Xihe, Achim Mester, Christian von Hebel, Egon Zimmermann, Harry Vereecken, Stefan van Waasen, and Jan van der Kruk. "Simultaneous calibration and inversion algorithm for multiconfiguration electromagnetic induction data acquired at multiple elevations." GEOPHYSICS 84, no. 1 (January 1, 2019): EN1—EN14. http://dx.doi.org/10.1190/geo2018-0264.1.
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Electromagnetic induction (EMI) is a contactless and fast geophysical measurement technique. Frequency-domain EMI systems are available as portable rigid booms with fixed separations up to approximately 4 m between the transmitter and the receivers. These EMI systems are often used for high-resolution characterization of the upper subsurface meters (up to depths of approximately 1.5 times the maximum coil separation). The availability of multiconfiguration EMI systems, which measure multiple apparent electrical conductivity ([Formula: see text]) values of different but overlapping soil volumes, enables EMI data inversions to estimate electrical conductivity ([Formula: see text]) changes with depth. However, most EMI systems currently do not provide absolute [Formula: see text] values, but erroneous shifts occur due to calibration problems, which hinder a reliable inversion of the data. Instead of using physical soil data or additional methods to calibrate the EMI data, we have used an efficient and accurate simultaneous calibration and inversion approach to avoid a possible bias of other methods while reducing the acquisition time for the calibration. By measuring at multiple elevations above the ground surface using a multiconfiguration EMI system, we simultaneously obtain multiplicative and additive calibration factors for each coil configuration plus an inverted layered subsurface electrical conductivity model at the measuring location. Using synthetic data, we verify our approach. Experimental data from five different calibration positions along a transect line showed similar calibration results as the data obtained by more elaborate vertical electrical sounding reference measurements. The synthetic and experimental results demonstrate that the multielevation calibration and inversion approach is a promising tool for quantitative electrical conductivity analyses.
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Комков, О. С. "Инфракрасное фотоотражение полупроводниковых материалов A-=SUP=-3-=/SUP=-B-=SUP=-5-=/SUP=- ( О б з о р )." Физика твердого тела 63, no. 8 (2021): 991. http://dx.doi.org/10.21883/ftt.2021.08.51146.032.
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Photoreflectance is a contactless type of modulation optical spectroscopy. It is used to study the band structure features of monocrystalline semiconductors, their doping level, the composition of alloys, as well as surface and interface band bending. Using high-quality GaAs as an example, the possibilities of describing the photoreflectance lineshape by one-electron and exciton models are demonstrated. The spectra of ultrapure samples of this material exhibit an oscillating structure well described by excitonic effects. For III-V alloys, a review of photoreflectance results concerning the effect of composition and temperature on the band gap and spin-orbit splitting is carried out. Determination of the position of the Fermi level on the surface (Fermi level pinning) for III-V crystals is considered. The currently developing technique for measuring photoreflectance in the mid-infrared range (photomodulation Fourier transform infrared spectroscopy) is described in detail. It is shown that phase correction plays a decisive role in such measurements. Original results demonstrate the capabilities of this method in a wide wavelength range.
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"EAS new digital position sensor offers contactless measurement of magnetic field fluctuations." Microelectronics International 30, no. 2 (April 26, 2013). http://dx.doi.org/10.1108/mi.2013.21830baa.013.
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Lüddecke, Bernhardt, Dietmar Filsinger, Jan Ehrhard, Bastian Steinacher, Christian Seene, and Michael Bargende. "Contactless Shaft Torque Detection for Wide Range Performance Measurement of Exhaust Gas Turbocharger Turbines." Journal of Turbomachinery 136, no. 6 (December 10, 2013). http://dx.doi.org/10.1115/1.4025824.
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Turbochargers develop away from an auxiliary component—being “off the shelve”—towards an integrated component of the internal combustion engine. Hence, increased attention is paid to the accuracy of the measured turbine and compressor maps. Especially turbine efficiency measurement under engine-relevant operating conditions (pulsed flow) is recently receiving increased attention in the respective research community. Despite various turbine map extrapolation methods, sufficient accuracy of the input test data is indispensable. Accurate experimental data are necessary to achieve high quality extrapolation results, enabling a wide range and precise prediction of turbine behavior under unsteady flow conditions, determined by intermittent operation of the internal combustion engine. The present work describes the first application of a contactless shaft torque measurement technique—based on magnetostriction—to a small automotive turbocharger. The contactless torque measuring system is presented in detail and sensor principle as well as sensor calibration are illustrated. A sensitivity study regarding sensor position influences onto sensor signal proves the robustness and very good repeatability of the system. In the second part of the paper, steady state experimental results from operation on a conventional hot gas test stand over a wide map range are presented. These results are validated against full turbine stage (adiabatic as well as diabatic) CFD results as well as against “cold” efficiency measurements, based on measured inlet and outlet temperatures. The influence and relevance of bearing friction for such measurements is underlined and the improvements on this matter—achieved by direct torque measurement—are demonstrated.
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Behr, Sabrina C., Christopher Platen, Pascal Vetter, Nicole Heussen, Steffen Leonhardt, Thorsten Orlikowsky, and Konrad Heimann. "Detection of acute ventilatory problems via magnetic induction in a newborn animal model." Pediatric Research, June 8, 2021. http://dx.doi.org/10.1038/s41390-021-01594-4.
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Abstract Background Magnetic induction measurement (MIM) is a noninvasive method for the contactless registration of respiration in newborn piglets by using measurement coils positioned at the bottom of an incubator. Acute pulmonary problems may be determinants of poor neurological and psychomotor outcomes in preterm infants. The current study tested the detection of pulmonary ventilation disorders via MIM in 11 newborn piglets. Methods Six measurement coils determined changes in magnetic induction, depending on the ventilation of the lung, in comparison with flow resistance. Contactless registration of induced acute pulmonary ventilation disorders (apnea, atelectasis, pneumothorax, and aspiration) was detected by MIM. Results All pathologies except aspiration were detected by MIM. Significant changes occurred after induction of apnea (three coils), malposition of the tube (one coil), and pneumothorax (three coils) (p ≤ 0.05). No significant changes occurred after induction of aspiration (p = 0.12). Conclusions MIM seems to have some potential to detect acute ventilation disorders in newborn piglets. The location of the measurement coil related to the animal’s position plays a critical role in this process. In addition to an early detection of acute pulmonary problems, potential information pointing to a therapeutic intervention, for example, inhalations or medical respiratory analepsis, may be conceivable with MIM in the future. Impact MIM seems to be a method in which noncontact ventilation disorders of premature and mature infants can be detected. This study is an extension of the experimental setup to obtain preliminary evidence for detection of respiratory activity in neonatal piglets. For the first time, MIM is used to register acute ventilation problems of neonates. The possibility of an early detection of acute ventilation problems via MIM may provide an opportunity to receive patient-side information for therapeutical interventions like inhalations or medical respiratory analepsis.
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Tiryaki, E., V. Singh, and A. H. Tewfik. "Distance Measuring Device Over Body Surface." Journal of Medical Devices 3, no. 2 (June 1, 2009). http://dx.doi.org/10.1115/1.3147517.
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Nerve conduction studies help to diagnose muscle and nerve diseases and point to the underlying cause and potential treatments. Conduction studies involve stimulating nerve at different points along its course and recording the response with an electrode, conduction velocity is determined by dividing the distance traveled by the time it takes the impulse to travel that distance. While the measurement of time is done electronically and is very accurate, measurement of distance in every commercial laboratory is done by marking the skin and measuring the distance with a flexible tape measure. Such distance measurement is highly error prone and leads to erroneous results and misdiagnosis. We present a device to measure distances along the body surface. It eliminates examiner error in the measurement of distance. It delivers an operator-independent and reproducible measurement and thereby increases accuracy of test results and avoids misdiagnosis. Furthermore, the device saves a significant amount of time. Stopping to pull out a tape measure, reading it and entering the data into the computer, all adds time to the length of the procedure. The measurement device eliminates these steps thereby increasing efficiency. It also transmits the measured distances directly to the computer, thus eliminating error in data entry. The device uses the established optical mouse technology at its core. It can measure displacements with a 0.0635 mm resolution. It is based on a commercial chip set, ADNS-5030 from ‘Avago Technologies.’ The system consists of an optoelectronic sensor which measures changes in position by optically acquiring sequential skin surface images (frames) and mathematically determining the direction and magnitude of movement. The sensor only needs to be pointing at but not touching the skin. The main advantage of this approach is that it is contactless, eliminating the need for disinfection. Although, current limitation of the device is in measuring accurately over non-planar surface due to its considerably large size making it difficult to maneuver over bumpy surfaces. Initial results for measurement studies performed over a diverse subject pool (in terms of skin color, hair density) results are promising with an error less than 9% for distances over 75 mm. A reduction in size of the device would lead to more accurate results as smaller size would help in easy maneuverability. Future implementations will exploit the contactless feature and integrate the measurement in the stimulus probe, reducing testing time and the need to operate multiple devices.
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Gumbs, G. "Effective Dielectric Function of Porous Silicon: the Transverse Component." MRS Proceedings 358 (1994). http://dx.doi.org/10.1557/proc-358-49.
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ABSTRACTA self-consistent many-body theory is developed to study the effect of temperature and electron density on the interband absorption coefficient and the frequency-dependent refractive index for an array of isolated quantum wires. The peaks in the absorption coefficient correspond to interband transitions resulting in the resonant absorption of light. The oscillations in the derivative spectrum are due to the quantization of the energy levels related to the in-plane confining potential for such reduced dimensional systems. There are appreciable changes in the absorption spectrum when the electron density or temperature is increased. One interband transition peak is suppressed in the high electron density limit and the thermal depopulation effect on the electron subbands can be easily seen when the temperature is high. We also find that the exciton coupling weakens the shoulder features in the absorption spectrum. This study is relevant to optical characterization of the confining potential and the areal density of electrons using photoreflectance. By using incident light with tunable frequencies in the interband excitation regime, contactless photoreflectance measurements may be carried out and the data compared with our calculations. By fitting the numerical results to the peak positions of the photoreflectance spectrum, the number of electrons in each wire may be extracted.