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Temperature dependence of a garnet-type optical current sensor
摘要： A garnet-type optical current sensor (OCS) is studied. Ta/Nd2Fe14B/Ta groove ?lms are prepared on garnet by a magnetron sputtering method. The measurement errors of the Faraday rotation angle and the Verdet constant of the garnet-type and garnet-groove ?lm OCSs are measured by Thorlabs polarimeters as a function of temperature. The results show that the measurement errors of the Faraday rotation angle of the garnet-type and garnet-groove ?lm OCSs are 1.5% and 0.3%, respectively, when the current is 700 A at room temperature. The measurement error of the garnet-groove magnetic ?lm OCS is lower than 0.3%, when the current changes from 0 to 1000 A and the temperature changes from 25 °C to 80 °C. The Verdet constant variations of the garnet-type and garnet-groove ?lm OCSs cause di?erent measurement errors when the temperature is changed.
关键词： Measurement error,Temperature,Faraday e?ect,Garnet
更新于2025-09-19 17:15:36
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Graphene Tunability for Transmission Type Terahertz Chiral Metamaterial
摘要： Deployment algorithms proposed to improve coverage in sensor networks often rely on the Voronoi diagram, which is obtained by using the position information of the sensors. It is usually assumed that all measurements are sufficiently accurate, while in a practical setting, even a small measurement error may lead to significant degradation in the coverage performance. This paper investigates the effect of measurement error on the performance of coverage control in mobile sensor networks. It also presents a distributed deployment strategy, namely the Robust Max-Area strategy, which uses information on error bounds in order to move the sensors to appropriate locations. To this end, two polygons are obtained for each sensor, and it is shown that the exact Voronoi polygon (associated with accurate measurements) lies between them. A local spatial probability function is then derived for each sensor, which translates the available information about the error bound into the likelihood of the points being inside the exact Voronoi polygon. Subsequently, the deployment strategy positions each sensor such that the total covered area increases. The sensors’ movements are shown to be convergent under the proposed strategy.
关键词： measurement error,mobile agents,Coverage control,Wireless sensor networks
更新于2025-09-19 17:13:59
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Impact of Resolution and Texture of Laser Scanning Generated Three‐Dimensional Models on Landmark Identification
摘要： The aim of the study was to determine the impact of the resolution and texture of 3D models created through laser scanning on the measurement error (ME) of craniometric landmarks. Ten skulls were scanned at five different resolutions, and the generated 3D models were exported with and without texture. The 3D coordinates of 28 landmarks were derived. Each landmark was picked five times by one observer. The ME of a definite landmark was calculated as an average of distances between the repeated placements of the landmark by the observer and the landmark centroid. One-way ANOVA was applied for detection of significant differences in the MEs between and within landmark types recorded at different resolutions. The MEs of landmark types in textured and non-textured models were compared by a paired test. Twelve linear measurements were calculated as interlandmark distances and their values obtained on the models of different resolution were compared. The Frankfurt horizontal plane was constructed for each model and its deviation was calculated at different resolutions. Scan resolution impacted MEs of Type 1 and 2 landmarks, but not the precision level of Type 3 landmarks. Texture most influenced the precise identification of Type 1 landmarks. The interlandmark distances between Type 2 landmarks were most consistent in their values, those between Type 1 landmarks showed deviations in low-resolution models, and distances between Type 3 landmarks demonstrated various patterns of transition of the values throughout the resolutions. Altogether, the use of textured high-resolution models would be preferable in morphometric studies.
关键词： Laser scanning,3D model,craniometric landmarks,texture,measurement error,resolution
更新于2025-09-19 17:13:59
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Comparative Evaluation of the Accuracy and Robustness of Various Information Processing Algorithms from Tripled Measuring Channels
摘要： Using the example of a three-channel system for measuring the level of filling of tanks of launch vehicles, we perform a comparative assessment of the accuracy and robustness of various algorithms for processing measurement information received from three measuring channels of the same type. We consider various processing algorithms of three equal-precision measurements: finding the arithmetic mean of three equal-precision measurements and a majority choice of three equal-precision measurements. For these algorithms, the probability density function of the measurement errors and confidence limits of the measurement error are found using the assumption of uniform or normal laws of the error distribution of three equally accurate measurements. A generalized algorithm for processing redundant information is proposed. The essence of the generalized algorithm is the addition of three equally accurate measurements taking into account individual weighting factors. Weight coefficients are selected based on the values of three equally accurate measurements: the minimum and maximum values are assigned the same weighting coefficient, and the median is assigned a coefficient which normalizes the sum of the three weighting factors to one. For a generalized algorithm by means of simulation modeling, the confidence limits of the measurement error are determined depending on the selected weighting factors. The robustness of the considered processing algorithms is evaluated for three equally accurate measurements performed on three measuring channels identical in design, with a random perturbation applied to one of the channels. Recommendations on the selection of weights for three equal measurements are given. For the fuel level measurement system under consideration, it is justified to use an algorithm for processing measurement information based on a majority choice of three equally accurate measurements.
关键词： algorithms for processing redundant measurement information,probability density distribution of measurement errors,robustness,weight coefficients,confidence limits of measurement error,Monte Carlo simulation
更新于2025-09-12 10:27:22
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Relief-Frequency Characteristics of Laser Scanners
摘要： The concept of the relief-frequency characteristic of laser scanners is introduced. The necessity of using the relief-frequency characteristic is substantiated with a description of the frequency properties of laser scanners. A procedure for experimental determination of the relief-frequency characteristic of laser scanners has been developed, and studies were carried out. It is shown that the relief-frequency characteristic makes it possible to estimate most precisely the error of the laser scanner and to determine the range of reproduced spatial frequencies when scanning a relief. The proposed procedure can be used to describe the metrological characteristic of laser scanners.
关键词： sampling,laser scanning,relief-frequency characteristic,measurement error,spatial-frequency characteristic,convolution
更新于2025-09-12 10:27:22
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[Lecture Notes in Electrical Engineering] Recent Trends in Communication, Computing, and Electronics Volume 524 (Select Proceedings of IC3E 2018) || Image Quality Assessment: A Review to Full Reference Indexes
摘要： An image quality index plays an increasingly vital role in image processing applications for dynamic monitoring and quality adjustment, optimization and parameter setting of the imaging systems, and finally benchmarking the image processing techniques. All the above goals highly require a sustainable quantitative measure of image quality. This manuscript analytically reviews the popular reference-based metrics of image quality which have been employed for the evaluation of image enhancement techniques. The efficiency and sustainability of eleven indexes are evaluated and compared in the assessment of image enhancement after the cancellation of speckle, salt and pepper, and Gaussian noises from MRI images separately by a linear filter and three varieties of morphological filters. The results indicate more clarity and sustainability of similarity-based indexes. The direction of designing a universal similarity-based index based on information content of the image is suggested as a future research direction.
关键词： Image quality measurement,Noise cancellation,Similarity measurement,Error measurement,Image enhancement
更新于2025-09-04 15:30:14