Journal of Sensors and Sensor Systems最新文献

{"title":"An internet of things (IoT)-based optimum tea fermentation detection model using convolutional neural networks (CNNs) and majority voting techniques","authors":"Gibson Kimutai, Alexander Ngenzi, Said Rutabayiro Ngoga, R. Ramkat, Anna Förster","doi":"10.5194/JSSS-10-153-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-153-2021","url":null,"abstract":"Abstract. Tea (Camellia sinensis) is one of the most consumed drinks across the world. Based on processing techniques, there are more than 15 000 categories of tea, but the main categories include yellow tea, Oolong tea, Illex tea, black tea, matcha tea, green tea, and sencha tea, among others. Black tea is the most popular among the categories worldwide. During black tea processing, the following stages occur: plucking, withering, cutting, tearing, curling, fermentation, drying, and sorting. Although all these stages affect the quality of the processed tea, fermentation is the most vital as it directly defines the quality. Fermentation is a time-bound process, and its optimum is currently manually detected by tea tasters monitoring colour change, smelling the tea, and tasting the tea as fermentation progresses. This paper explores the use of the internet of things (IoT), deep convolutional neural networks, and image processing with majority voting techniques in detecting the optimum fermentation of black tea. The prototype was made up of Raspberry Pi 3 models with a Pi camera to take real-time images of tea as fermentation progresses. We deployed the prototype in the Sisibo Tea Factory for training, validation, and evaluation. When the deep learner was evaluated on offline images, it had a perfect precision and accuracy of 1.0 each. The deep learner recorded the highest precision and accuracy of 0.9589 and 0.8646, respectively, when evaluated on real-time images. Additionally, the deep learner recorded an average precision and accuracy of 0.9737 and 0.8953, respectively, when a majority voting technique was applied in decision-making. From the results, it is evident that the prototype can be used to monitor the fermentation of various categories of tea that undergo fermentation, including Oolong and black tea, among others. Additionally, the prototype can also be scaled up by retraining it for use in monitoring the fermentation of other crops, including coffee and cocoa.\u0000","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43574165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of uncertainties for measurements of total near-normal emissivity of low-emissivity foils with an industrial emissometer","authors":"J. Hameury, G. Failleau, M. Arduini, J. Manara, E. Kononogova, A. Adibekyan, C. Monte, Alexander Kirmes, Eric Palacio, Holger Simon","doi":"10.5194/JSSS-10-135-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-135-2021","url":null,"abstract":"Abstract. The TIR100-2 emissometer (manufactured by Inglas GmbH & Co.KG) is an emissivity measurement device used by several producers of thermal insulation products for buildings and by some organizations certifying performance of insulation products. A comparison of emissivity measurements on low-emissivity foils involving different measurement techniques, including the TIR100-2 emissometer, gave widely dispersed results; the discrepancies were\u0000not explained. The metrological performance of the TIR100-2 emissometer and the uncertainties for measurement on reflective foils was not known, which could be detrimental to users. In order to quantify the performance of TIR100-2 devices for measurement of total near-normal emissivity of low-emissivity foils, the Laboratoire National de Metrologie et d'Essais (LNE) analyzed in detail the measuring principle and listed the associated assumptions and uncertainty sources. A TIR100-2\u0000emissometer actually measures the reflectance and, for opaque materials, the emissivity is calculated from the measured reflectance. The parameters\u0000analyzed experimentally are the temperature stability and uniformity of the thermal radiation source, the emissivity of the radiation source, the\u0000response function linearity and the spectral sensitivity of the radiometric detection system measuring the reflected radiation, the size of the\u0000measurement area, and the measurement repeatability and reproducibility. A detailed uncertainty budget was established. The uncertainty sources taken into account are the uncertainties of the emissivities of the two calibrated standards used for calibration, the stability and uniformity of the\u0000radiation source temperature, the non-linearity and the spectral sensitivity of the radiometric detection system, the specific measurement condition\u0000related to the radiation source temperature, the uncertainties related to the temperatures of the standards and the sample, the noises on results, and the non-homogeneity in emissivity of the tested material. The combined measurement uncertainty was calculated for different types of reflective\u0000foils; the expanded uncertainty is around 0.03 for total near-normal emissivity measurements on smooth low-emissivity foils. A measurement campaign on five types of low-emissivity foils, involving four TIR100-2 emissometers, and a comparison to a primary reference setup at the Physikalisch-Technische Bundesanstalt (PTB) confirmed the uncertainties assessed.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"10 1","pages":"135-152"},"PeriodicalIF":1.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45676855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A classification technique of group objects by artificial neural networks using estimation of entropy on synthetic aperture radar images","authors":"A. V. Kvasnov, V. Shkodyrev","doi":"10.5194/JSSS-10-127-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-127-2021","url":null,"abstract":"Abstract. The article discusses the method for the classification of non-moving group objects for information received from unmanned aerial vehicles (UAVs) by synthetic aperture radar (SAR). A theoretical approach to analysis of group objects can be estimated by cross-entropy using a naive Bayesian classifier. The entropy of target spots on SAR images revaluates depending on the altitude and aspect angle of a UAV. The paper shows that classification of the target for three classes able to predict with fair accuracy P = 0,964 based on an artificial neural network. The study of results reveals an advantage compared with other radar recognition methods for a criterion of the constant false-alarm rate (PCFAR < 0.01). The reliability was confirmed by checking the initial data using principal component analysis.\u0000","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49074588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of optimal crystallographic orientations for LiNbO3 and LiTaO3 bimorph actuators","authors":"O. Buryy, I. Syvorotka, Y. Suhak, U. Yakhnevych, D. Sugak, S. Ubizskii, H. Fritze","doi":"10.5194/JSSS-10-121-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-121-2021","url":null,"abstract":"Abstract. The actuators for precise positioning based on bimorph\u0000structures of piezoelectric LiNbO 3 and LiTaO 3 crystals are\u0000considered. The optimal orientations of the actuator plates ensuring the\u0000highest possible displacements are determined by the extreme surfaces\u0000technique and the finite-element method. The simulated displacements for optimal orientations of LiNbO 3 and LiTaO 3 plates are compared with\u0000those obtained experimentally for manufactured LiNbO 3 and LiTaO 3 actuators, whose orientations are not optimal. As is shown, the optimal configuration of the actuator allows us to significantly increase its displacement\u0000for both LiNbO 3 and LiTaO 3 specimens.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"10 1","pages":"121-126"},"PeriodicalIF":1.0,"publicationDate":"2021-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41593189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Absolute calibration of the spectral responsivity of thermal detectors in the near-infrared (NIR) and mid-infrared (MIR) regions by using blackbody radiation","authors":"Tobias T. Pohl, P. Meindl, L. Werner, U. Johannsen, D. Taubert, C. Monte, J. Hollandt","doi":"10.5194/JSSS-10-109-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-109-2021","url":null,"abstract":"Abstract. The Physikalisch-Technische Bundesanstalt (PTB) has set up an additional measurement approach for the absolute calibration of the spectral responsivity of detectors in the near-infrared (NIR) and mid-infrared (MIR) spectral range. This alternative method uses the radiation of a blackbody operating at about 1200 K with a precision aperture. The blackbody radiation can be calculated by Planck's law and is additionally spectrally selected by accurately characterized optical bandpass filters. Thus, a calibration of the spectral responsivity of a detector with respect to irradiance can be achieved at the bandpass wavelength of the applied transmission filters. If the aperture of the detector is known, the spectral responsivity can also be calculated with respect to radiant power. Thermopile detectors with known aperture size were calibrated in terms of\u0000their spectral responsivity with several bandpass filters in the spectral\u0000range between 1.5  µ m up to 14  µ m with relative standard\u0000measurement uncertainties between 5 % and 19 %. The obtained results\u0000are consistent with previous calibrations at PTB's national primary detector standard. Therefore, this additional measurement approach is a further validation of the existing primary method which is based on a cryogenic radiometer and extends the usable wavelength range.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"10 1","pages":"109-119"},"PeriodicalIF":1.0,"publicationDate":"2021-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45336097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement uncertainty assessment for virtual assembly","authors":"M. Kaufmann, I. Effenberger, M. Huber","doi":"10.5194/JSSS-10-101-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-101-2021","url":null,"abstract":"Virtual assembly (VA) is a method for datum definition and quality prediction of assemblies considering local form deviations of relevant geometries. Point clouds of measured objects are registered in order to recreate the objects’ hypothetical physical assembly state. By VA, the geometrical verification becomes more accurate and, thus, increasingly function oriented. The VA algorithm is a nonlinear, constrained derivate of the Gaussian best fit algorithm, where outlier points strongly influence the registration result. In order to assess the robustness of the developed algorithm, the propagation of measurement uncertainties through the nonlinear transformation due to VA is studied. The work compares selected propagation methods distinguished from their levels of abstraction. The results reveal larger propagated uncertainties by VA compared to the unconstrained Gaussian best fit. 1 Current trends in dimensional metrology and state-of-the-art datum definition and uncertainty assessment As quality demands on products increase, tolerance specifications for parts become more and more complex. With these challenging geometrical specifications, verification algorithms are required that represent the geometrical system more precisely. According to Nielsen (2003), in the last few decades, dimensional tolerances shrank due to improved manufacturing systems. However, the form deviations could not be reduced by the same extent. Therefore, their consideration should be intensified. A main deficit in the current International Organization for Standardization (ISO) standard for datum definition, ISO 5459 (Deutsches Institut für Normung e.V., 2011), is the lack of consideration of local form deviations for datum features. A datum feature is defined as a “real (non-ideal) integral feature used for establishing a single datum” (Deutsches Institut für Normung e.V., 2017, p. 2). Datum systems composed of three datum features mathematically define a coordinate system. This allows the definition of tolerance zones for extrinsic tolerances (Weißgerber and Keller, 2014). About 80 % of all measurement tasks require datum systems, so a further function-oriented datum system definition has a strong impact on geometrical verification. Hence, an assessment of the uncertainty for datum systems is of broad interest. Figure 1 shows a datum definition, where three perpendicular associated planes are considered in a nested approach. The primary datum constrains 3 degrees of freedom (DOF), the secondary datum 2 DOF and the tertiary datum 1 DOF (Gröger, 2015). 1.1 Concept of the virtual assembly In this paper, measurement data of physical objects are gathered from measurements using industrial computed tomography (CT). Registration is the action of aligning a data set relatively to another according to a datum definition in a common coordinate system. Virtual assembly (VA) comprises the consideration of local form deviations in the datum system computation. As shown in Fig. 1a, th","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"10 1","pages":"101-108"},"PeriodicalIF":1.0,"publicationDate":"2021-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47001547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Studies on porosity in poly(N-isopropylacrylamide) hydrogels for fast-responsive piezoresistive microsensors","authors":"D. Franke, G. Gerlach","doi":"10.5194/JSSS-10-93-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-93-2021","url":null,"abstract":"Porous poly(N -isopropylacrylamide) (PNIPAAm) hydrogels with pore diameters in the nanometer and the micrometer range were synthesized using two variations of the surfactant-based template method. We showed that smaller pore diameters lead to faster swelling and deswelling. A graphic representation of a model describing the swelling kinetics explains the assumption that the release and the uptake of water is faster for a larger specific surface area, that is smaller pore diameters. Additionally, the open-porous channel structure benefits the water transport compared to a nonporous PNIPAAm hydrogel. Sensor measurements result in response times between 36 s and 4 min also showing the importance of mechanical stability of porous hydrogels.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"10 1","pages":"93-100"},"PeriodicalIF":1.0,"publicationDate":"2021-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44630731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ceramic multilayer technology as a platform for miniaturized sensor arrays for water analysis","authors":"C. Feller, U. Partsch","doi":"10.5194/JSSS-10-83-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-83-2021","url":null,"abstract":"Abstract. Ion-selective electrodes (ISEs) have been proven particularly useful in water\u0000analysis. They are usually used as single-rod measuring chains in different\u0000designs, which are manufactured using precision mechanical manufacturing and\u0000assembling technologies. The paper describes a microsystem technology approach\u0000for the fabrication of miniaturized electrochemical sensors. The ceramic HTCC (high-temperature co-fired ceramic)\u0000and LTCC (low-temperature co-fired ceramic) multilayer technology enables suitable processes for the\u0000manufacturing of robust and miniaturized sensor arrays with a high functional\u0000density. Design, manufacture, and electrochemical performance of the novel\u0000ceramic multilayer-based sensor array are presented in the paper using various\u0000examples. An adapted material and process development was carried out for the\u0000sensitive functional films. Special thick-film pastes for the detection of the\u0000pH value as well as NH 4 + , K+ , Ca2+ ,\u0000and Cu2+ ion concentrations in aqueous solutions were\u0000developed. Ion-sensitive thick-film membranes were deposited on a ceramic\u0000multilayer sensor platform by means of screen-printing. All ISEs, integrated\u0000in the sensor array, showed suitable electrochemical performances including a\u0000very quick response (several seconds) combined with a high sensitivity\u0000(exhibiting Nernstian behaviour) in the tested measuring range. The obtained\u0000sensitivities were around 57  mVper decade : for the pH sensor,\u000030  mVper decade for calcium, 53  mVper decade for potassium,\u0000and 57  mVper decade for ammonium. Depending on the application,\u0000different sensitive electrodes on the ceramic sensor array can be combined as\u0000required.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"10 1","pages":"83-91"},"PeriodicalIF":1.0,"publicationDate":"2021-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45268864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel, low-cost device to simultaneously measure the electrical conductivity and the Hall coefficient from room temperature up to 600 °C","authors":"R. Werner, J. Kita, M. Gollner, F. Linseis, R. Moos","doi":"10.5194/JSSS-10-71-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-71-2021","url":null,"abstract":"Abstract. A novel measurement device for simultaneous high temperature measurements of the electrical conductivity and the Hall coefficient has been developed. Simulations were used to design a suitable screen-printed planar platinum heating structure that generates temperatures of up to 600  ∘ C by Joule heating. Simulations of the temperature distribution have been validated using thermal imaging. With the hardware setup of two permanent magnetic yoke systems with a magnetic flux density of ±760  mT, the electrical conductivity and the charge carrier densities of a silicon wafer and a gold film were measured, as examples of a typical semiconductor with low charge carrier densities but high mobility and a metal representing materials with very high charge carrier densities but moderate mobilities, respectively. Measurements were compared with data from the literature to validate the functionality of the novel, low-cost measurement device.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"10 1","pages":"71-81"},"PeriodicalIF":1.0,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43446219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Method for fast determination of the angle of ionizing radiation incidence from data measured by a Timepix3 detector","authors":"Felix Lehner, J. Roth, O. Hupe, Marc Kassubeck, B. Bergmann, P. Mánek, M. Magnor","doi":"10.5194/JSSS-10-63-2021","DOIUrl":"https://doi.org/10.5194/JSSS-10-63-2021","url":null,"abstract":"Abstract. This paper presents a method of how to determine spatial angles of ionizing radiation incidence quickly, using a Timepix3 detector. This work focuses on the dosimetric applications where detectors and measured quantities show significant angle dependencies. A determined angle of incidence can be used to correct for the angle dependence of a planar Timepix3 detector. Up until now, only passive dosemeters have been able to provide a correct dose and preserve the corresponding incidence angle of the radiation. Unfortunately, passive dosemeters cannot provide this information in “real” time. In our special setup we were able to retrieve the spatial angles with a runtime of less than 600 ms. Employing the new Timepix3 detector enables the use of effective data analysis where the direction of incident radiation is computed from a simple photon event map. In order to obtain this angle, we combine the information extracted from the map with known 3D geometry surrounding the detector. Moreover, we analyze the computation time behavior, conditions and optimizations of the developed spatial angle calculation algorithm.","PeriodicalId":17167,"journal":{"name":"Journal of Sensors and Sensor Systems","volume":"10 1","pages":"63-70"},"PeriodicalIF":1.0,"publicationDate":"2021-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48853253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}