Artículos de revistas: "Area Projection Transform"

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YANG, JIANWEI, LIANG ZHANG y ZHENGDA LU. "THE MELLIN CENTRAL PROJECTION TRANSFORM". ANZIAM Journal 58, n.º 3-4 (7 de marzo de 2017): 256–64. http://dx.doi.org/10.1017/s1446181116000341.

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The central projection transform can be employed to extract invariant features by combining contour-based and region-based methods. However, the central projection transform only considers the accumulation of the pixels along the radial direction. Consequently, information along the radial direction is inevitably lost. In this paper, we propose the Mellin central projection transform to extract affine invariant features. The radial factor introduced by the Mellin transform, makes up for the loss of information along the radial direction by the central projection transform. The Mellin central projection transform can convert any object into a closed curve as a central projection transform, so the central projection transform is only a special case of the Mellin central projection transform. We prove that closed curves extracted from the original image and the affine transformed image by the Mellin central projection transform satisfy the same affine transform relationship. A method is provided for the extraction of affine invariants by employing the area of closed curves derived by the Mellin central projection transform. Experiments have been conducted on some printed Chinese characters and the results establish the invariance and robustness of the extracted features.

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Dorrek, Felix y Franz E. Schuster. "Projection functions, area measures and the Alesker–Fourier transform". Journal of Functional Analysis 273, n.º 6 (septiembre de 2017): 2026–69. http://dx.doi.org/10.1016/j.jfa.2017.06.003.

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3

Zhou, Xiaohui y Baoqin Wang. "Wavelet analysis on some smooth surface with nonzero constant Gaussian curvature". International Journal of Wavelets, Multiresolution and Information Processing 16, n.º 01 (enero de 2018): 1850007. http://dx.doi.org/10.1142/s0219691318500078.

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According to the theory of wavelet analysis on [Formula: see text], the wavelet analysis on a smooth surface [Formula: see text] with nonzero constant Gaussian curvature will be discussed systematically in this paper. First, a general area-preserving projection from a smooth surface to the plane will be presented by the Gaussian projection and the area-preserving projection on the sphere. Then the continuous wavelet transform and its inverse transform on a smooth surface [Formula: see text] with nonzero constant Gaussian curvature will be discussed by a general area-preserving projection, relative dilation operator and translation operator. Further, according to the multi-resolution analysis on a smooth surface, the discrete wavelet transform and relative properties will be investigated systematically, including the two-scale equations of the wavelet function, orthogonality and so on. Finally, two numerical examples will be given.

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Wang, Bao Qin, Gang Wang, Xiao Hui Zhou y Yu Su. "Wavelet analysis on developable surface base on area preserving projection". International Journal of Wavelets, Multiresolution and Information Processing 13, n.º 01 (enero de 2015): 1550007. http://dx.doi.org/10.1142/s0219691315500071.

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In this paper, a simple method is given in order to construct an area preserving mapping from a developable surface M to a plane. Based on the area preserving projection, we give some important formulas on M, and define a multi-resolution analysis on L2(M). We provide the conditions to further discuss the continuous wavelet transform and discrete wavelet transform on developable surface. At the same time, we derived two-scale equations that the scaling function and wavelet function on developable surface satisfied, we also define and discuss the orthogonality, and several important theorems are given. Finally, we construct the numerical examples. The focus of this paper is the area preserving mapping that from developable surface M to a plane, and the discrete wavelet transform on developable surface.

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MA, Tong Yi y Li Li Zhang. "Lp−Winterniz problem on firey projection of convex bodies". Tamkang Journal of Mathematics 45, n.º 2 (30 de junio de 2014): 179–93. http://dx.doi.org/10.5556/j.tkjm.45.2014.1017.

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For $p\geq 1$, Lutwak, Yang and Zhang introduced the concept of $p$-projection body, and Lutwak introduced the concept of $L_{p}-$ affine surface area of convex body. In this paper, we develop the Minkowski-Funk transform approach in the $L_{p}$-Brunn-Minkowski theory. We consider the question of whether $\Pi_{p}K\subseteq \Pi_{p}L$ implies $\Omega_{p}(K) \leq \Omega_{p}(L)$, where $\Pi_{p}K$ and $\Omega_{p}K$ denotes the $p-$projection body of convex body $K$ and the $L_{p}-$affine surface area of convex body $K$, respectively. We also formulate and solve a generalized $L_{p}-$Winterniz problem for Firey projections.

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6

Suzuki, Sodai, Yuichi Akatsuka, Wei Jiang, Motoharu Fujigaki y Masaaki Otsu. "Development of Quick Three-Dimensional Shape Measurement Projection Mapping System Using a Whole-Space Tabulation Method". Applied Sciences 9, n.º 20 (18 de octubre de 2019): 4408. http://dx.doi.org/10.3390/app9204408.

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A grating projection method is often used as a highly accurate 3D shape measurement method. A real-time 3D shape measurement system can also be applied to measure a wide and smooth curved surface, such as in sheet metal processing. In this case, operators take much effort to recognize the positions of some problem areas on an object from a measured result displayed on a monitor. This study develops a projection mapping system projecting an evaluation image, such as height, displacement, gradient, curvature factor, and area of defect, onto an object. These evaluation results are obtained from the measured 3D shape. The evaluation image should be deformed according to the 3D shape of the object because the camera and projector positions are different. Therefore, this study proposes a method to quickly produce a deformed evaluation image using a whole-space tabulation method. A coordinate transform table allowed the conversion of a camera pixel coordinate into a projector pixel coordinate by using reference planes to apply deformation to the evaluation image according to the measured 3D shape. The quick coordinate transformation from a camera pixel coordinate into a projector pixel coordinate was realized using the coordinate transform table. This is a key idea of this study. It was confirmed that the coordinate transformation from the camera pixel coordinate to the projector coordinate could be performed in 4.5 ms using the coordinate transform table. In addition, 3D shape measurement projection mapping was applied to a curved sheet metal with small deformation, and the deformation part was clearly shown by projecting the height distribution. The architecture and the experimental results are shown herein.

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7

Giachetti, A. y C. Lovato. "Radial Symmetry Detection and Shape Characterization with the Multiscale Area Projection Transform". Computer Graphics Forum 31, n.º 5 (agosto de 2012): 1669–78. http://dx.doi.org/10.1111/j.1467-8659.2012.03172.x.

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Tian, Xi Jie, Jing Yu y Chang Chun Li. "Identification of the Hook on Investment Casting Shell Line Based on Machine Vision". Applied Mechanics and Materials 220-223 (noviembre de 2012): 1356–61. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.1356.

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In this paper, the idea identify the hook on investment casting shell line based on machine vision has been proposed. According to the characteristic of the hook, we do the image acquisition and preprocessing, we adopt Hough transform to narrow the target range, and find the target area based on the method combining the level projection and vertical projection, use feature matching method SIFT to do the image matching. Finally, we get the space information of the target area of the hook.

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9

Yan, Jin, Tiansheng Xu, Ni Li y Guanghong Gong. "Regression and Evaluation on a Forward Interpolated Version of the Great Circle Arcs–Based Distortion Metric of Map Projections". ISPRS International Journal of Geo-Information 10, n.º 10 (26 de septiembre de 2021): 649. http://dx.doi.org/10.3390/ijgi10100649.

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We studied the numerical approximation problem of distortion in map projections. Most widely used differential methods calculate area distortion and maximum angular distortion using partial derivatives of forward equations of map projections. However, in certain map projections, partial derivatives are difficult to calculate because of the complicated forms of forward equations, e.g., equations with iterations, integrations, or multi-way branches. As an alternative, the spherical great circle arcs–based metric employs the inverse equations of map projections to transform sample points from the projection plane to the spherical surface, and then calculates a differential-independent distortion metric for the map projections. We introduce a novel forward interpolated version of the previous spherical great circle arcs–based metric, solely dependent on the forward equations of map projections. In our proposed numerical solution, a rational function–based regression is also devised and applied to our metric to obtain an approximate metric of angular distortion. The statistical and graphical results indicate that the errors of the proposed metric are fairly low, and a good numerical estimation with high correlation to the differential-based metric can be achieved.

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10

Feng, Xiang, Yang-chun Song, Zhi-quan Zhou y Yi-nan Zhao. "Designing Unimodular Waveform with Low Range Sidelobes and Stopband for Cognitive Radar via Relaxed Alternating Projection". International Journal of Antennas and Propagation 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/6280508.

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Cognitive radar could adapt the spectrum of waveforms in response to information regarding the changing environment, so as to avoid narrowband interference or electronic jamming. Besides stopband constraints, low range sidelobes and unimodular property are also desired. In this paper, we propose a Spectral Approximation Relaxed Alternating Projection (SARAP) method, to synthesize unimodular waveform with low range sidelobes and spectral power suppressed. This novel method, based on phase retrieval and relaxed alternating projection, could convert the correlation optimization into the spectrum approximation via the Fast Fourier Transform (FFT). Moreover, by virtue of the relaxation factor and accelerated factor, SARAP can exploit local area and more likely converge to the global solution. Numerical trials have demonstrated that SARAP could achieve excellent performance and computational efficiency which will facilitate the real-time design.

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Algarni, Abeer D., Ghada M. El Banby, Naglaa F. Soliman, Fathi E. Abd El-Samie y Abdullah M. Iliyasu. "Efficient Implementation of Homomorphic and Fuzzy Transforms in Random-Projection Encryption Frameworks for Cancellable Face Recognition". Electronics 9, n.º 6 (24 de junio de 2020): 1046. http://dx.doi.org/10.3390/electronics9061046.

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To circumvent problems associated with dependence on traditional security systems on passwords, Personal Identification Numbers (PINs) and tokens, modern security systems adopt biometric traits that are inimitable to each individual for identification and verification. This study presents two different frameworks for secure person identification using cancellable face recognition (CFR) schemes. Exploiting its ability to guarantee irrevocability and rich diversity, both frameworks utilise Random Projection (RP) to encrypt the biometric traits. In the first framework, a hybrid structure combining Intuitionistic Fuzzy Logic (IFL) with RP is used to accomplish full distortion and encryption of the original biometric traits to be saved in the database, which helps to prevent unauthorised access of the biometric data. The framework involves transformation of spatial-domain greyscale pixel information to a fuzzy domain where the original biometric images are disfigured and further distorted via random projections that generate the final cancellable traits. In the second framework, cancellable biometric traits are similarly generated via homomorphic transforms that use random projections to encrypt the reflectance components of the biometric traits. Here, the use of reflectance properties is motivated by its ability to retain most image details, while the guarantee of the non-invertibility of the cancellable biometric traits supports the rationale behind our utilisation of another RP stage in both frameworks, since independent outcomes of both the IFL stage and the reflectance component of the homomorphic transform are not enough to recover the original biometric trait. Our CFR schemes are validated on different datasets that exhibit properties expected in actual application settings such as varying backgrounds, lightings, and motion. Outcomes in terms standard metrics, including structural similarity index metric (SSIM) and area under the receiver operating characteristic curve (AROC), suggest the efficacy of our proposed schemes across many applications that require person identification and verification.

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Huang, Xiaoyu, Xuemei Wang, Kawuqiati Baishan y Baisong An. "Hyperspectral Estimation of Soil Organic Carbon Content Based on Continuous Wavelet Transform and Successive Projection Algorithm in Arid Area of Xinjiang, China". Sustainability 15, n.º 3 (1 de febrero de 2023): 2587. http://dx.doi.org/10.3390/su15032587.

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Soil organic carbon (SOC), an important indicator to evaluate soil fertility, is essential in agricultural production. The traditional methods of measuring SOC are time-consuming and expensive, and it is difficult for these methods to achieve large area measurements in a short time. Hyperspectral technology has obvious advantages in soil information analysis because of its high efficiency, convenience and non-polluting characteristics, which provides a new way to achieve large-scale and rapid SOC monitoring. The traditional mathematical transformation of spectral data in previous studies does not sufficiently reveal the correlation between the spectral data and SOC. To improve this issue, we combine the traditional method with the continuous wavelet transform (CWT) for spectral data processing. In addition, the feature bands are screened with the successive projection algorithm (SPA), and four machine learning algorithms are used to construct the SOC content estimation model. After the spectral data is processed by CWT, the sensitivity of the spectrum to the SOC content and the correlation between the spectrum and the SOC content can be significantly improved (p < 0.001). SPA was used to compress the spectral data at multiple decomposition scales, greatly reducing the number of bands containing covariance and enabling faster screening of the characteristic bands. The support vector machine regression (SVMR) model of CWT-R′ gave the best prediction, with the coefficients of determination (R2) and the root mean square error (RMSE) being 0.684 and 1.059 g∙kg−1, respectively, and relative analysis error (RPD) value of 1.797 for its validation set. The combination of CWT and SPA can uncover weak signals in the spectral data and remove redundant bands with covariance in the spectral data, thus realizing the screening of characteristic bands and the fast and stable estimation of the SOC content.

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Lai, Zhipeng, Chengjing Chen, Jianguo Chen, Zhuo Wu, Fang Wang y Shaoying Li. "Multi-Scenario Simulation of Land-Use Change and Delineation of Urban Growth Boundaries in County Area: A Case Study of Xinxing County, Guangdong Province". Land 11, n.º 9 (17 de septiembre de 2022): 1598. http://dx.doi.org/10.3390/land11091598.

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Delineating urban growth boundaries (UGBs) by combining the land-use/land-cover (LULC) change simulation method has become common in recent studies. However, few of the existing studies have integrated multi-source big data to analyze the driving factors of LULC dynamics in the simulation. Moreover, most of previous studies mainly focused on the UGBs delineation in macroscale areas rather than small-scale areas, such as the county area. In this study, taking Xinxing County of Guangdong Province as the study area, we coupled a system dynamics (SD) model and a patch-generating land-use simulation (PLUS) model to propose a framework for the LULC change simulation and UGBs delineation in the county area. Multi-source big data such as points of interest (POIs), night-time light (NTL) data and Tencent user density (TUD) were integrated to analyze the driving forces of LULC change. The validation results indicate that the coupled model received high accuracy both in the land-use demand projection and LULC distribution simulation. The combination of multi-source big data can effectively describe the influence of human socio-economic factors on the expansion of urban land and industrial land. The UGBs delineation results have similar spatial patterns with the LULC change simulation results, which indicates that the proposed UGBs delineation method can effectively transform the LULC simulation results into available UGBs for the county area. It has been proven that the proposed framework in this study is effective for the LULC change simulation and UGBs delineation in the county area, which can provide insight on territorial spatial planning in the county area.

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Li, Lingling, Tao Gao y Yaoquan Yang. "Direct Part Mark Bar Code Image Preprocessing". International Journal of Advanced Pervasive and Ubiquitous Computing 7, n.º 3 (julio de 2015): 13–24. http://dx.doi.org/10.4018/ijapuc.2015070102.

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Due to factors such as ambient light and metal materials, the collected industrial DPM bar code images may exist uneven illumination, low contrast, color of background area is darker than bar code region and other harsh issues, while the existing 2D code recognition device can only recognize the type which bar code area color is darker than background region. Therefore, the quality of preprocessing effect is the key point to subsequent recognition algorithm. In this paper, the homomorphic filtering method is used to weaken the influence of uneven illumination firstly, which will enhance the image contrast degree. Then do horizontal and vertical projection, find the points with greater intensity changes in both directions, make the image into blocks, again use the classic Kittler binarization algorithm on each block, then use mathematical morphology method to standardize the dot data matrix images. Finally, an improved Hough transform method is used to detect the ‘L' type finder pattern accurately, then find its pixel value, if color of the background region is darker than the bar code area, do invert-color processing. The processing results of a set of industrial DPM bar code images confirm the effectiveness of the proposed method.

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Zhang, Lingzhi, Haomin Dai, Jialin Zhang, Zhiqiang Zheng, Bo Song, Jiaya Chen, Gang Lin, Linhai Chen, Weijiang Sun y Yan Huang. "A Study on Origin Traceability of White Tea (White Peony) Based on Near-Infrared Spectroscopy and Machine Learning Algorithms". Foods 12, n.º 3 (21 de enero de 2023): 499. http://dx.doi.org/10.3390/foods12030499.

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Identifying the geographical origins of white tea is of significance because the quality and price of white tea from different production areas vary largely from different growing environment and climatic conditions. In this study, we used near-infrared spectroscopy (NIRS) with white tea (n = 579) to produce models to discriminate these origins under different conditions. Continuous wavelet transform (CWT), min-max normalization (Minmax), multiplicative scattering correction (MSC) and standard normal variables (SNV) were used to preprocess the original spectra (OS). The approaches of principal component analysis (PCA), linear discriminant analysis (LDA) and successive projection algorithm (SPA) were used for features extraction. Subsequently, identification models of white tea from different provinces of China (DPC), different districts of Fujian Province (DDFP) and authenticity of Fuding white tea (AFWT) were established by K-nearest neighbors (KNN), random forest (RF) and support vector machine (SVM) algorithms. Among the established models, DPC-CWT-LDA-KNN, DDFP-OS-LDA-KNN and AFWT-OS-LDA-KNN have the best performances, with recognition accuracies of 88.97%, 93.88% and 97.96%, respectively; the area under curve (AUC) values were 0.85, 0.93 and 0.98, respectively. The research revealed that NIRS with machine learning algorithms can be an effective tool for the geographical origin traceability of white tea.

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Wübbeler, Gerd, Manuel Marschall, Eckart Rühl, Bernd Kästner y Clemens Elster. "Compressive nano-FTIR chemical mapping". Measurement Science and Technology 33, n.º 3 (24 de diciembre de 2021): 035402. http://dx.doi.org/10.1088/1361-6501/ac407a.

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Abstract Nano-Fourier-transform infrared spectroscopy (nano-FTIR) combines infrared spectroscopy with scanning probe microscopy (SPM) techniques and enables spectroscopic imaging of molecular and electronic properties of matter at nanometer spatial resolution. The spectroscopic imaging can be used to derive chemical mappings, i.e. the spatial distribution of concentrations of the species contained in a given sample. However, due to the sequential scanning principle underlying SPM, recording the complete spectrum over a large spatial area leads to long measurement times. Furthermore, the acquired spectrum often contains additional signals from species and lineshape effects that are not explicitly accounted for. A compressive chemical mapping approach is proposed for undersampled nano-FTIR data that utilizes sparsity of these additional signals in the spectral domain. The approach combines a projection technique with standard compressed sensing, followed by a spatially regularized regression. Using real nano-FTIR measurements superimposed by simulated interferograms representing the chemical mapping of the contained species, it is demonstrated that the proposed procedure performs well even in cases in which the simulated interferograms and the sparse additional signals exhibit a strong spectral overlap.

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Úcar, Xavier. "Exploring different perspectives of Social Pedagogy: towards a complex and integrated approach." education policy analysis archives 21 (30 de abril de 2013): 36. http://dx.doi.org/10.14507/epaa.v21n36.2013.

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Some characterizations describe social pedagogy as a broad, complex, ambiguous and problematic concept that applies to very different things. This is due to the simplicity of the tools used to approach such a complex area. A change of perspective to interpret social pedagogy as a hybrid and complex subject may transform the alleged deficiencies into strengths and promise. This paper provides elements that enable such a change. To this end, some misunderstandings regarding social pedagogy are presented. These misunderstandings are scenarios and factors that have contributed (1) to the generation of inaccuracies and confusions about what social pedagogy is, could, or should do, and (2) to the projection of an inconsistent and poorly defined image of social pedagogy, i.e. a discipline without method and an ineffective and inefficient practice for solving social problems. The social pedagogy that emerges from the six misunderstandings (cognitive, policy-related, scientist, action-related, normative and social) is complex. From the new perspective, it is more of a hybrid subject (a concept, a discipline and a practice) that is complex, open, dynamic and ever changing.

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Lenoir, Guillaume y Michel Crucifix. "A general theory on frequency and time–frequency analysis of irregularly sampled time series based on projection methods – Part 2: Extension to time–frequency analysis". Nonlinear Processes in Geophysics 25, n.º 1 (5 de marzo de 2018): 175–200. http://dx.doi.org/10.5194/npg-25-175-2018.

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Abstract. Geophysical time series are sometimes sampled irregularly along the time axis. The situation is particularly frequent in palaeoclimatology. Yet, there is so far no general framework for handling the continuous wavelet transform when the time sampling is irregular. Here we provide such a framework. To this end, we define the scalogram as the continuous-wavelet-transform equivalent of the extended Lomb–Scargle periodogram defined in Part 1 of this study (Lenoir and Crucifix, 2018). The signal being analysed is modelled as the sum of a locally periodic component in the time–frequency plane, a polynomial trend, and a background noise. The mother wavelet adopted here is the Morlet wavelet classically used in geophysical applications. The background noise model is a stationary Gaussian continuous autoregressive-moving-average (CARMA) process, which is more general than the traditional Gaussian white and red noise processes. The scalogram is smoothed by averaging over neighbouring times in order to reduce its variance. The Shannon–Nyquist exclusion zone is however defined as the area corrupted by local aliasing issues. The local amplitude in the time–frequency plane is then estimated with least-squares methods. We also derive an approximate formula linking the squared amplitude and the scalogram. Based on this property, we define a new analysis tool: the weighted smoothed scalogram, which we recommend for most analyses. The estimated signal amplitude also gives access to band and ridge filtering. Finally, we design a test of significance for the weighted smoothed scalogram against the stationary Gaussian CARMA background noise, and provide algorithms for computing confidence levels, either analytically or with Monte Carlo Markov chain methods. All the analysis tools presented in this article are available to the reader in the Python package WAVEPAL.

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Aoyagi, Seiji, Atsushi Kohama, Yuki Inaura, Masato Suzuki y Tomokazu Takahashi. "Image-Searching for Office Equipment Using Bag-of-Keypoints and AdaBoost". Journal of Robotics and Mechatronics 23, n.º 6 (20 de diciembre de 2011): 1080–90. http://dx.doi.org/10.20965/jrm.2011.p1080.

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For an indoor mobile robot’s Simultaneous Localization And Mapping (SLAM), a method of processing only one monocular image (640×480 pixel) of the environment is proposed. This method imitates a human’s ability to grasp at a glance the overall situation of a room, i.e., its layout and any objects or obstacles in it. Specific object recognition of a desk through the use of several camera angles is dealt with as one example. The proposed method has the following steps. 1) The bag-of-keypoints method is applied to the image to detect the existence of the object in the input image. 2) If the existence of the object is verified, the angle of the object is further detected using the bag-ofkeypoints method. 3) The candidates for the projection from template image to input image are obtained using Scale Invariant Feature Transform (SIFT) or edge information. Whether or not the projected area correctly corresponds to the object is checked using the AdaBoost classifier, based on various image features such as Haar-like features. Through these steps, the desk is eventually extractedwith angle information if it exists in the image.

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Natsiopoulos, Dimitrios A., Elisavet G. Mamagiannou, Eleftherios A. Pitenis, Georgios S. Vergos y Ilias N. Tziavos. "GOCE Downward Continuation to the Earth’s Surface and Improvements to Local Geoid Modeling by FFT and LSC". Remote Sensing 15, n.º 4 (10 de febrero de 2023): 991. http://dx.doi.org/10.3390/rs15040991.

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One of the main applications of the gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite data is their combination with local gravity anomalies for geoid and gravity field modeling purposes. The aim of the present paper was the determination of an improved geoid model for the wider Hellenic area, using original GOCE SGG data filtered to retain only useful signals inside the measurement bandwidth (MBW) of the satellite. The filtered SGGs, originally at the satellite altitude, were projected to a mean orbit (MO) and then downward continued to the Earth’s surface (ES) in order to be combined with local gravity anomalies. For the projection to an MO, grids of disturbing gravity gradients from a global geopotential model (GGM) were used, computed per 1 km from the maximum satellite altitude to that of the MO. The downward continuation process was then undertaken using an iterative Monte Carlo (MC) simulated annealing method with GGM gravity anomalies on the ES used as ground truth data. The final geoid model over the wider Hellenic area was estimated, employing the remove–compute–restore method and both Fast Fourier Transform (FFT) and Least Squares Collocation (LSC). Gravity-only, GOCE-only and combined models using local gravity and GOCE data were determined and evaluation of the results was carried out against available GNSS/levelling data in the study area. From the results achieved, it was concluded that even when FFT is used, so that a combined grid of local gravity and GOCE data is used, improvements to the differences regarding GNSS/levelling data by 14.53% to 27.78% can be achieved. The geoid determination with LSC was focused on three different areas over Greece, with different characteristics in the topography and gravity variability. From these results, improvements from 14.73%, for the well-surveyed local data of Thessaly, to 32.88%, over the mountainous area of Pindos, and 57.10% for the island of Crete for 57.10% were found.

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Wang, Yunxun, Hanspeter Winkler, Michael K. Reedy, Mary C. Reedy y Kenneth A. Taylor. "Electron Tomography of Swollen Rigor Fibers of Insect Flight Muscle Reveals the S2 Fragment of Myosin". Microscopy and Microanalysis 7, S2 (agosto de 2001): 98–99. http://dx.doi.org/10.1017/s1431927600026568.

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We have used electron tomography of rigorized fibers of insect flight muscle swollen by immersion in dilute buffer (†1mM MOPS, pH 6.8), to reveal the 3-D arrangement of the myosin S2 fragment for the first time. S2 is an α-helical coiled-coil structure that connects the myosin head to the thick filament backbone. It is usually invisible in electron micrographs because of its close proximity to the backbone. The increase in inter-thick filament spacing from 45 nm to 55 nm pulls the S2 away from the filament backbone making it easier to identify. A total of 4 tomograms have been calculated by our standard method which involves collecting images using non-uniformly spaced tilt angles, cross correlation alignment, area matching and Whittaker-Shannon interpolation of the 3-D transform. A projection of one of these tomograms is shown in Figure 1. in raw tomograms S2 appears as a rod-like structure that originates at the thick filament surface to connect to both lead and rear crossbridges of rigor. S2 segments are particularly well resolved at the ends of the thick filament (Fig. 2), where in some cases it appears that the myosin subfilaments are separated from the backbone. Both the azimuthal direction and axial angle of S2 are variable.

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HOMAEINEZHAD, MOHAMMAD R., MOHAMMAD AGHAEE, HAMID NAJJARAN TOOSI, ALI GHAFFARI y REZA RAHMANI. "APPLICATION OF THE DISCRETE WAVELET TRANSFORM FOR THE ROBUST DETECTION OF THE IMPULSIVE INCIDENCES: APPLICATION TO ARTERIAL BLOOD PRESSURE CHARACTERISTIC EVENTS DETECTION–DELINEATION". International Journal of Wavelets, Multiresolution and Information Processing 09, n.º 05 (septiembre de 2011): 813–42. http://dx.doi.org/10.1142/s0219691311004328.

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The major focus of this study is to describe the structure of a solution designed for robustly detecting and delineating the arterial blood pressure (ABP) signal events. To meet this end, first, the original ABP signal is pre-processed by application of à trous discrete wavelet transform (DWT) for extracting several dyadic scales. Then, a fixed sample size sliding window is moved on the appropriately selected scale and in each slid, six features namely as summation of the nonlinearly amplified Hilbert transform, summation of absolute first-order differentiation, summation of absolute second-order differentiation, curve length, area and variance of the excerpted segment are calculated. Then, all feature trends are normalized and utilized to construct a newly proposed principal components analyzed geometric index (PCAGI) (to be used as the segmentation decision statistic (DS)) by application of a linear orthonormal projection. After application of an adaptive-nonlinear transformation for making the DS baseline stationary, the histogram parameters of the enhanced DS are used to regulate the α-level Neyman–Pearson classifier for false alarm probability (FAP)-bounded delineation of the ABP events. In order to illustrate the capabilities of the presented algorithm, it was applied to all 18 subjects of the MIT-BIH Polysomnographic Database (359,000 beats) and the end-systolic and end-diastolic locations of the ABP signal as well as dicrotic notch pressure were extracted and values of sensitivity and positive predictivity Se = 99.86% and P+ = 99.95% were obtained for the detection of all ABP events. High robustness against measurement noises, acceptable detection-delineation accuracy of the ABP events in the presence of severe heart valvular and arrhythmic dysfunctions within a tolerable computational burden (processing time) and having no parameters dependency to the acquisition sampling frequency can be mentioned as the important merits and capabilities of the proposed PCAGI-based ABP events detection-segmentation algorithm.

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Zhang, Yuanmin, Zhu Jiang y Junfeng Lu. "Research on Leakage Location of Pipeline Based on Module Maximum Denoising". Applied Sciences 13, n.º 1 (27 de diciembre de 2022): 340. http://dx.doi.org/10.3390/app13010340.

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Leak detection and location of water supply pipelines is an important area of research, and it is especially important to find the leakage location in time and repair them. In view of the problem, that a large amount of noise is mixed in the detection signal when the pipeline leaks, it will inevitably affect the detection and positioning effect. In this paper, a denoising algorithm based on improved module maximum is proposed. Firstly, a discrete binary wavelet transform is carried out on the noisy signal, and the module maximum point corresponding to the wavelet transform coefficients, on each scale, is obtained. Secondly, different thresholds are used for the module maximum of different scale layers and the wavelet coefficients are reconstructed according to the retained module maximum and their extremums. Thirdly, the alternative projection algorithm is used to effectively suppress the false oscillations in the reconstructed signal, improve the quality of the reconstructed signal, and obtain the noise reduction signal. Finally, according to the theory of the negative pressure wave, the inflection point of the negative pressure wave is identified by the wavelet decomposition method, and the location of leakage point is determined. In order to verify the effectiveness of the proposed algorithm, a leakage simulation experiment system of water supply pipeline is built. The analysis of the results shows that, compared with the wavelet denoising method and the EMD-based method, the method proposed in this paper achieves a better denoising effect, obtains a smoother pressure signal, retains the signal waveform characteristics, and identifies the obvious inflexion point of the negative pressure wave. The minimum relative error of leakage point location is 0.9%, and the maximum relative error is 2.5%.

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24

Cięszczyk, Sławomir, Damian Harasim, Ainur Ormanbekova, Krzysztof Skorupski y Martyna Wawrzyk. "Methods of Projecting Mode Amplitude Changes on the Wavelength Axis in Order to Determine the Bending Radius on the Basis of TFBG Grating Spectra". Sensors 21, n.º 22 (12 de noviembre de 2021): 7526. http://dx.doi.org/10.3390/s21227526.

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Tilted fibre Bragg grating (TFBG) are used as sensors to determine many quantities such as refractive index, temperature, stress, rotation and bending. The TFBG spectrum contains a lot of information and various algorithms are used for its analysis. However, most of these algorithms are dedicated to the analysis of spectral changes under the influence of the refractive index. The most popular algorithm used for this purpose is to calculate the area occupied by cladding modes. Among the remaining algorithms, there are those that use the determination of the cut-off wavelength as a surrounding refractive index (SRI) indicator. Projection on the wavelength axis can also be used to calculate the bending radius of the fibre. However, this is a more difficult task than with SRI, because the mode decay in bending is not so easy to catch. In this article, we propose a multi-step algorithm that allows to determine the impact of bending on mode leakage. At the same time, the place on the wavelength from the side of the Bragg mode and the ghost mode is determined, which represents the cladding mode radiated from the cladding under the influence of bending. The developed algorithm consists of the following operations carried out on the transmission spectrum: Fourier filtering, calculation of the cumulative value of the spectral length, low-pass filtering of the cumulative curve or its corresponding polynomial approximation, determination of the first and second derivative of the approximated curve, and projection of the second derivative of the curve on the wavelength axis. The shift of the wavelength determined in this way indirectly indicates the bending radius of the optical fibre. Based on multiple measurements, we prove that the presented algorithm provides better results when determining the bending radius compared to other algorithms adopted for this purpose and proposed for SRI measurements. Additionally, we analyse the method of determining the shift of a fragment of the spectrum using the phase of the discrete Fourier transform.

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25

Irfan, Muhammad, Masooma Irfan, Ani Idris, Abdullah Saad Alsubaie, Khaled H. Mahmoud, Noordin Mohd Yusof y Naeem Akhtar. "Dual Optimized Sulfonated Polyethersulfone and Functionalized Multiwall Carbon Tube Based Composites High Fouling Resistance Membrane for Protein Separation". Membranes 12, n.º 3 (16 de marzo de 2022): 329. http://dx.doi.org/10.3390/membranes12030329.

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Commercial grade sulfonated-Polyethersulfone (S-PES) and functionalized multiwall carbon nanotube (f-MWCNT)/polyvinylpyrrolidone (PVP) nanocomposites (NCs) were used to enhance and optimize the antifouling, protein resistance and protein separation properties of the S-PES ultrafiltration membranes. The polarities of sulfonic groups of S-PES, carbonyl carbon of pyrrolidone, hydroxyl and carboxyl groups of f-MWCNT in the membrane composition helped to strongly bind each other through hydrogen bonding, as shown by Fourier-transform infrared spectroscopy (FTIR). These binding forces greatly reduced the leaching of NCs and developed long finger-like projection, as confirmed by elution ratio and cross-sectional studies of the membranes via field emission scanning electron microscope (FESEM). The contact angle was reduced up to 48% more than pristine PES. Atomic force microscopy (AFM) was employed to study the various parameters of surface roughness with 3d diagrams, while grain analysis of membrane surface provided a quantitative estimation about volume, area, perimeter, length, radius and diameter. The NCs/S-PES enhanced the flux rate with an impressive (80–84%) flux recovery ratio and (58–62%) reversible resistance (Rr) value in situ, with 60% and 54.4% lesser dynamic and static protein adsorption. The best performing membrane were reported to remove 31.8%, 66.3%, 83.6% and 99.9% for lysozyme-(14.6 kDa), trypsin-(20 kDa), pepsin-(34.6 kDa) and bovine serum albumin (BSA-66 kDa), respectively.

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26

Ibrahim, Elkhedr, Mohamed Arfaoui, Saad Mogren, Saleh Qaysi, Aref Lashin y Hussain Alfaifi. "Disposition of magmatic eruptions and fault distribution in northwestern Saudi Arabia using pseudo-depth slice magnetic anomaly". Journal of Geophysics and Engineering 18, n.º 4 (agosto de 2021): 463–81. http://dx.doi.org/10.1093/jge/gxab028.

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Abstract This study presents the disposition of magmatic eruptions with a fault distribution in northwestern Saudi Arabia, where intensive magma invades the lithosphere. Structural and magmatic features are traced at successive depths through high-resolution magnetic anomaly pseudo-depth slices. The total horizontal gradient technique is applied to pseudo-depth slice magnetic anomalies to enhance the linear trends of faults and related magmatic activity. A comprehensive cross-section constructed from the projection of gradient horizontal maxima relative to pseudo-slices allows the visualization of the vertical behavior of faults and magma sources. Three major fault systems were identified, primarily aligned in the N–S, NE–SW and NW–SE directions. They are characterized by increasing length and width with depth. The N-S fault system is a major non-planar deep system throughout the area, affected by the NW–SE and NE–SW deep discontinuities. The evolution of these discontinuities with depth successfully shows magma uprising zones represented by a circular horizontal gradient, which starts to appear at a depth of 4500 m with a vertical continuity to the surface. They are interpreted as possible locations of ascending magma chambers or vents. The disposition of these magma sources with fault distribution can show a close relationship between the fault systems and the magma eruptions. The interpreted magma vents appear where the NE-trending transform faults intersect the NW or N–S fault zone. These intersections may represent weak zones that act as vertical conduits through which magma discontinuously erupts into the overlying crust, forming major volcanic fields in the eastern Red Sea.

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27

Strebe, Daniel “daan”. "A bevy of area-preserving transforms for map projection designers". Cartography and Geographic Information Science 46, n.º 3 (5 de abril de 2018): 260–76. http://dx.doi.org/10.1080/15230406.2018.1452632.

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28

Zhu, Zhiyuan, Yuanfei Cai, Kexing Song, Yanjun Zhou y Jiasheng Zou. "Precipitation Characteristics of the Metastable γ″ Phase in a Cu-Ni-Be Alloy". Materials 11, n.º 8 (9 de agosto de 2018): 1394. http://dx.doi.org/10.3390/ma11081394.

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The precipitation sequence of a Cu-Ni-Be alloy is: α-Cu supersaturated solid solution → Guinier-Preston (G.P.) zones → metastable γ″ → γ′ → stable γ (NiBe) phase. The micro-hardness and electrical conductivity during the aging process were measured. The precipitation characteristics and the distribution of the γ″ phase, under peak aging conditions, were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area diffraction pattern (SADP), and high-resolution transmission electron microscopy (HRTEM). The results show that the orientation relationship of the γ′′ phase/α-Cu matrix is: (001)p//(001)α; [100]p//[110]α (p: Precipitates, α: α-Cu supersaturated solid solution), which is in accordance with the Bain relationship in a FCC/BCC (face centered cubic/body centered cubic) structure, with the unique habit plane being {001}α. While the zone axis is parallel to [001]α, three forms of γ″ phases are distributed on the projection surface at the same time. The (001) reciprocal-lattice positions of γ′′ phase in SADP are diffusely scattered, which is consistent with the variation of the d(001) value of the γ′′ phase. The intra-range variation is related to the distortion of the (001) plane of the γ″ phase, due to interfacial dislocations and distortion strain fields. The lattice of the γ″ phase in the HRTEM images was measured as a = b = 0.259 ± 0.002 nm and c = 0.27–0.32 nm. With the increase of thermal exposure time, the stable γ phase has a NiBe phase structure (Standard Card Number: PDF#03-1098, a = b = c = 0.261 nm), and the long diffuse scattering spots will transform into single bright spots. The edge dislocation, generated by interfacial mismatch, promotes the formation of an optimal structure of the precipitated phase, which is the priority of growth in the direction of [110]p.

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29

Corson, James A. y Robert M. Bradley. "Physiological and anatomical properties of intramedullary projection neurons in rat rostral nucleus of the solitary tract". Journal of Neurophysiology 110, n.º 5 (1 de septiembre de 2013): 1130–43. http://dx.doi.org/10.1152/jn.00167.2013.

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The rostral nucleus of the solitary tract (rNTS), the first-order relay of gustatory information, not only transmits sensory information to more rostral brain areas but also connects to various brain stem sites responsible for orofacial reflex activities. While much is known regarding ascending projections to the parabrachial nucleus, intramedullary projections to the reticular formation (which regulate oromotor reflexive behaviors) remain relatively unstudied. The present study examined the intrinsic firing properties of these neurons as well as their morphological properties and synaptic connectivity with primary sensory afferents. Using in vitro whole cell patch-clamp recording, we found that intramedullary projection neurons respond to depolarizing current injection with either tonic or bursting action potential trains and subsets of these groups of neurons express A-type potassium, H-like, and postinhibitory rebound currents. Approximately half of the intramedullary projection neurons tested received monosynaptic innervation from primary afferents, while the rest received polysynaptic innervation, indicating that at least a subpopulation of these neurons can be directly activated by incoming sensory information. Neuron morphological reconstructions revealed that many of these neurons possessed numerous dendritic spines and that neurons receiving monosynaptic primary afferent input have a greater spine density than those receiving polysynaptic primary afferent input. These results reveal that intramedullary projection neurons represent a heterogeneous class of rNTS neurons and, through both intrinsic voltage-gated ion channels and local circuit interactions, transform incoming gustatory information into signals governing oromotor reflexive behaviors.

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30

Sparling, Chris y Dave Townsend. "Tomographic reconstruction techniques optimized for velocity-map imaging applications". Journal of Chemical Physics 157, n.º 11 (21 de septiembre de 2022): 114201. http://dx.doi.org/10.1063/5.0101789.

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Examples of extracting meaningful information from image projection data using tomographic reconstruction techniques can be found in many areas of science. Within the photochemical dynamics community, tomography allows for complete three-dimensional (3D) charged particle momentum distributions to be reconstructed following a photodissociation or photoionization event. This permits highly differential velocity- and angle-resolved measurements to be made simultaneously. However, the generalized tomographic reconstruction strategies typically adopted for use with photochemical imaging—based around the Fourier-slice theorem and filtered back-projection algorithms—are not optimized for these specific types of problems. Here, we discuss pre-existing alternative strategies—namely, the simultaneous iterative reconstruction technique and Hankel Transform Reconstruction (HTR)—and introduce them in the context of velocity-map imaging applications. We demonstrate the clear advantages they afford, and how they can perform considerably better than approaches commonly adopted at present. Most notably, with HTR we can set a bound on the minimum number of projections required to reliably reconstruct 3D photoproduct distributions. This bound is significantly lower than what is currently accepted and will help make tomographic imaging far more accessible and efficient for many experimentalists working in the field of photochemical dynamics.

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31

Ziboon, Abdul Razzak y Israa Mohammed. "Accuracy evaluation of 2D geometric correction models: Iraq as a case study". MATEC Web of Conferences 162 (2018): 03015. http://dx.doi.org/10.1051/matecconf/201816203015.

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One of the most important preprocessing methods for remote sensing data and geometrical distrortion is the geometric correction. In this research, several mathematical models were used in two dimensions case and were compared to each other to determine the accuracy of each mathematical model when used in three different regions with different terrains. Three high-resolution satellite images of the QuickBird satellite (a flat area, a hilly area and a mountain area) of Iraq have been used in this work. The flat area is chosen in Baghdad, while the hilly and mountain areas are chosen in Irbil in the north of Iraq. In this research, the mathematical models used are the first and second order polynomials, as well as the projective transform. All of these models were applied to all different topographic areas and their accuracy was assessed based on the Matlab program. The results of the models in the three areas studied indicate that the best precision is achieved with the second order polynomial model, while the worst precision is obtained with the first order polynomial model. On the other hand, the precision of the projective transformation is almost similar to the precision of the first order polynomial.

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32

Shirazi, Muhammad Ayaz, Riaz Uddin y Min-Young Kim. "Supervised Learning Based Peripheral Vision System for Immersive Visual Experiences for Extended Display". Applied Sciences 11, n.º 11 (21 de mayo de 2021): 4726. http://dx.doi.org/10.3390/app11114726.

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Video display content can be extended to the walls of the living room around the TV using projection. The problem of providing appropriate projection content is hard for the computer and we solve this problem with deep neural network. We propose the peripheral vision system that provides the immersive visual experiences to the user by extending the video content using deep learning and projecting that content around the TV screen. The user may manually create the appropriate content for the existing TV screen, but it is too expensive to create it. The PCE (Pixel context encoder) network considers the center of the video frame as input and the outside area as output to extend the content using supervised learning. The proposed system is expected to pave a new road to the home appliance industry, transforming the living room into the new immersive experience platform.

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33

Zhang, Yuanjun, Xinghua Qu, Yiming Li y Fumin Zhang. "A Separation Method of Superimposed Gratings in Double-Projector Fringe Projection Profilometry Using a Color Camera". Applied Sciences 11, n.º 3 (20 de enero de 2021): 890. http://dx.doi.org/10.3390/app11030890.

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Fringe projection profilometry has been intensively studied for several decades. However, due to the limitation of the field range of a single projector, when measuring objects with complex surfaces, there are always shadow areas in the captured images, resulting in missing measurement data in the dark areas. To solve this problem, systems with double projectors and single camera were employed. Not only were the shadow areas reduced, but system recalibration and multiple measurements were not needed, improving measuring efficiency. Nevertheless, separating the corresponding projection pattern from the superimposed fringe presented a difficult problem. A color camera has RGB three color channels. When the color camera is applied to fringe projection profilometry, the information obtained is three times as much as that of the monochrome camera. Due to the small overlap between the red- and blue-light spectra response of color cameras, the channel color crosstalk can be ignored. This paper proposes a method to project red and blue fringe patterns from two projectors and utilize the characteristics of the red and blue channels of the color camera to separate the superposition grating pattern. The original patterns can be recovered integrally and easily. To explain the effectiveness of superimposed fringe separation, a simulation and experiments were carried out. Both of them showed that the superimposed fringe can be separated correctly, proving that our method is feasible.

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34

Perheentupa, Viljami, Ville Mäkinen y Juha Oksanen. "Making post-glacial uplift visible: A model based high-resolution animation of shore displacement". Abstracts of the ICA 1 (15 de julio de 2019): 1–2. http://dx.doi.org/10.5194/ica-abs-1-296-2019.

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Abstract. Glacial isostatic adjustment (GIA) is an ongoing phenomenon that characterizes the landscape of the High Coast (63°04'N, 18°22'E, Sweden) / Kvarken archipelago (63°16'N, 21°10'E, Finland) UNESCO World Heritage site. GIA occurs as the Earth’s crust that was depressed by the continental ice sheet during the last glacial period is slowly rebounding towards isostatic equilibrium. The maximum rate of land uplift in the area is more than eight millimetres per year, which &ndash; along with the very different topographical reliefs of the opposite coasts &ndash; makes the region an excellent study area for land uplift as a phenomenon. As there is a marine area between the coasts, shore displacement is an essential part of the phenomenon in the study area.The cartographic representation of GIA and shore displacement has classically relied on static maps representing isobases of the uplift rates and of ancient shorelines. However, to dynamically visualize and communicate the continuity and the nature of the phenomena, an animated map is required. To create a visually balanced, seamless animation, we need to create high-resolution image frames that represent digital elevation models (DEMs) together with extracted shorelines of different moments of time. To create these frames, we developed a mathematical model to transform the DEM in a given time for the past ~9300 years. We used the most recent LiDAR-derived DEMs of Finland and Sweden, and a bathymetric model of the Gulf of Bothnia as our initial data, along with a land uplift rate surface derived from geophysical measurements. We compared the current uplift rates with the shoreline observations of the ancient Baltic Sea stages, Litorina Sea and Ancylus Lake, and created a linear model between the elevations of the shorelines and the present-day uplift rates, as there was a near-linear correlation in both cases. Based on the current uplift rates and the elevations and the dating of the ancient shorelines, we derived an exponential model to describe the non-linear correlation between the elapsed time and the occurred land uplift. Near the present time, we adapted the formula proposed by Ekman (2001) to make the model more robust closer to the present day.We assumed that although the uplift rate varies in time, the spatial relation of uplift rates remains the same. Furthermore, as the land uplift is an exponentially decelerating phenomenon occurring with a significantly lower annual rate than shortly after the de-glaciation (Eronen et al. 2001, Nordman et al. 2015), and with most of the total uplift already having occurred (Ekman 1991), we assumed a constant rate of uplift from the present day to the near geological future. We did not consider potential sea level changes caused by human-driven climate change in the predictions, as the geological time scale vastly exceeds the time range of the climate models. Neither did we take into account the historical transgression phases, as they did not appear dominating in the area.The elevation and bathymetry data were harmonized and resampled into 4K (3840&thinsp;&times;&thinsp;2160) pixel dimensions to utilize the best commercially available screen resolutions and to avoid unnecessary sub-pixel level computations. This resulted in a spatial pixel size of about 200 metres. The initial spatial resolution of the DEMs of Finland and Sweden was 2 metres and 1 metre, respectively, while the bathymetric data had a spatial pixel size of 400 metres. This, along with the fact that the bathymetric data was partly modelled and inaccurate near the coastlines, meant that it had to be oversampled to generate plausible coastal bathymetry and to allow any future estimations of shore displacement. All the datasets were resampled to EPSG:3857 Pseudo-Mercator projection to facilitate any future use in web map applications. As the visualized area is only about 430 kilometres in the north-south direction, the use of this projection did not introduce cartographic issues.The rendered frames required by the animation were produced with a programmatic conversion of raster files to RGB-images. The visualization of shore displacement was implemented by a discontinuity in elevation dependent colour scale at sea level. The bathymetry was visualized with a continuous colour scale in shades of blue until the elevation of zero metres. Elevations above zero were visualized with a colour scale starting from green to create an impression of a discrete shoreline (Figure 1).The whole process from computing the DEMs to rendering the frames was implemented in Python, without the need for traditional GUI operated GIS or image processing software. The raster data was read and processed with GDAL and NumPy libraries, and the visualization was carried out using Matplotlib and Python Imaging Library. Each DEM was given the same elevation based colour scale and an individually created hillshading that was blended with the image by multiplication. The whole process was carried out as an open source solution.The interval between the calculated frames was set to five years as, particularly at the Swedish coast, the shore displacement can appear abrupt with a longer time interval. The frame duration was set to 0.05 seconds, which means a 100-second duration for an animation of 10&thinsp;000 years.The resulting DEM reconstructions show good agreement with comparable data, such as the Litorina reconstructions by the Geological Survey of Finland (GTK). Also, the mathematical model appears to be in line with previous reconstructions conducted in the area (e.g. Nordman et al. 2015). So far, any continuous series of paleogeographic DEM reconstructions comparable to ours has not been published for this area. The animation provides an understandable way of perceiving the continuous but decelerating nature of the land uplift phenomenon and also highlights the differences in the post-glacial history of Finnish and Swedish coasts. To further improve the visualization, we must consider the removal of post-glacially developed features in the present day DEM, e.g. the various rivers that can both cause bias in the shore displacement and uplift estimations and appear visually distractive. In the very early frames of the animation, the retracting ice sheet must also be present. Also, a balanced addition of other cartographic elements, such as present-day hydrography and place names, can further improve the overall presentation.

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35

Fernández-Rodicio, Enrique, Víctor González-Pacheco, José Carlos Castillo, Álvaro Castro-González, María Malfaz y Miguel A. Salichs. "Projection Surfaces Detection and Image Correction for Mobile Robots in HRI". Journal of Sensors 2017 (2017): 1–16. http://dx.doi.org/10.1155/2017/4853915.

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Projectors have become a widespread tool to share information in Human-Robot Interaction with large groups of people in a comfortable way. Finding a suitable vertical surface becomes a problem when the projector changes positions when a mobile robot is looking for suitable surfaces to project. Two problems must be addressed to achieve a correct undistorted image: (i) finding the biggest suitable surface free from obstacles and (ii) adapting the output image to correct the distortion due to the angle between the robot and a nonorthogonal surface. We propose a RANSAC-based method that detects a vertical plane inside a point cloud. Then, inside this plane, we apply a rectangle-fitting algorithm over the region in which the projector can work. Finally, the algorithm checks the surface looking for imperfections and occlusions and transforms the original image using a homography matrix to display it over the area detected. The proposed solution can detect projection areas in real-time using a single Kinect camera, which makes it suitable for applications where a robot interacts with other people in unknown environments. Our Projection Surfaces Detector and the Image Correction module allow a mobile robot to find the right surface and display images without deformation, improving its ability to interact with people.

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36

Nur Lina Abdullah, Norul Fadhilah Ismail, Saiful Bahri Safaron, Nurazeera Md Suder y Nurul Wahidah Omar. "Water Overlapping Area for The Arrangement of Field’s Sprinkler Irrigation". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 88, n.º 1 (11 de octubre de 2021): 140–48. http://dx.doi.org/10.37934/arfmts.88.1.140148.

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The design and arrangement of sprinkler irrigation systems are presented and discussed in this paper. The design is based on a rotating sprinkler system to irrigate the field. Information is provided concerning the components of irrigation systems and the characteristics of the system that affect water application efficiency. The mathematical model is developed to account for water overlapping area throughout a fixed sprinkler system and to evaluate the number of sprinkler irrigation for the whole field using water projection profiles from the experimental data analysis. As a result, a set of recommendations for the design of sprinkler irrigation system management are obtained. Finally, this problem is alleviated using the Maplet interface. By simply typing information in the text boxes and using drop-down menus in Maplet windows, the characteristic of sprinkler irrigation systems can be studied with relative ease.

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37

wang, Rong, Yuanyuan Ma, Di Zhang y Weihua Li. "Analysis of Polyphosphate during the Enhanced Biological Phosphorus Removal process using Fourier Transform Infrared (FTIR) spectroscopy". E3S Web of Conferences 145 (2020): 02077. http://dx.doi.org/10.1051/e3sconf/202014502077.

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Two enhanced biological phosphorus removal (EBPR) reactors were operated in synthetic wastewater with different Chemical Oxygen Demand/Phosphorus (COD/P) ratios. The sludge samples at different sample times were lyophilized and characterized by Fourier Transform Infrared (FTIR) spectroscopy. Results showed that the infrared spectral curves from two reactors were similar but the intensities were different at specific wavenumbers. The spectral intensities at 1260cm-1 and 890cm-1 of the sludge samples from the reactor at low COD/P ratios were relatively stronger, but those of the reactor at high COD/P ratios were relatively weaker. The principal component projection plot of FTIR spectra analyzed with principal components analysis (PCA) showed that the sludge samples at the same COD/P ratios assembled together implicating the principal component projection plot could discriminate the sludge samples from different reactor. The infrared peak near 890cm-1 was separated and integrated with Gaussian peak fitting method. The integrated areas were correlated to the polyphosphate content in the sludge. Results showed that the prediction values were in good accordance with those determined by chemical method. This work provides a new method for the recognition of polyphosphate in sludge and provides a basis for the rapid determination of polyphosphate.

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38

Senin, Nicola, Michele Moretti y Liam A. Blunt. "Identification of individual features in areal surface topography data by means of template matching and the ring projection transform". Surface Topography: Metrology and Properties 2, n.º 1 (23 de diciembre de 2013): 014007. http://dx.doi.org/10.1088/2051-672x/2/1/014007.

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39

Liu, Chun-Hsi, Chun-Yu Hsiao, Jyh-Cherng Gu, Kuan-Yi Liu, Chih-Hung Chang, Chen-En Lee y Shu-Fen Yan. "Assessment the Visual Clarity of the Projector in Classroom and Innovative Asymmetric Distribution LED Tube Applications". Applied Sciences 11, n.º 23 (24 de noviembre de 2021): 11153. http://dx.doi.org/10.3390/app112311153.

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The paper aims to explore the relationship between the vertical plane luminance on projection screens and human visual clarity in the classroom or meeting room. While controlling the lighting environment conditions of the classroom to create different luminous distributions and luminance on the projection screen, a survey is conducted to understand students’ visual experience about screen clarity during the field experiment. The luminance of each picture on the projection screen is measured under the specified lighting conditions of luminaires in the classroom, and the relationship is formulated between the average luminance on the projection screen and the visual satisfaction based on clarity of experience. This will be useful for further studying the acceptable threshold of luminance distribution in the classroom to provide a better visual clarity and lighting quality of projection screens while teaching. In this study, the measurement and performance evaluation on a projection screen were carried out at a classroom in the National Taiwan University of Science and Technology (NTUST). By using an image luminance meter and analyzing the research results, we propose an improvement strategy for asymmetric luminous distribution design of LED light tube and light switch control mechanism of luminaires to resolve the inadequate luminance of the vertical projection screen area to improve the lighting quality and visual clarity of the projection screen while teaching with the least cost.

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40

Ku, Yi-Sha, Po-Yi Chang, Han-Wen Lee, Chun-Wei Lo, Yi-Chang Chen y Chia-Hung Cho. "Metrology for Measuring Bumps in a Protection Layer Based on Phase Shifting Fringe Projection". Applied Sciences 12, n.º 2 (17 de enero de 2022): 898. http://dx.doi.org/10.3390/app12020898.

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We developed a telecentric 3D measurement system based on the fringe projection technique to measure phases corresponding to the 3D shape of bumps on a surface. A measurement algorithm based on an area scan camera with a flexibly programmable region of interest (ROI) was applied to reconstruct the 3D model. Only the pixel information within the ROI is stored, which reduces the data volume and processing and accelerates the area scan acquisition. Experiments showed that the fringe projection system provided good linearity between the calibration and optical data with excellent accuracy. A reflectometry sensor was implemented to provide a correction offset to the bump height in a protection layer in a subsequent high-speed inspection.

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41

Kobiela, Konrad, Michał Jedynak, Wiktor Harmatys, Marcin Krawczyk y Jerzy A. Sładek. "Assessment of Laser Galvanometer Scanning System Accuracy Using Ball-Bar Standard". Applied Sciences 11, n.º 19 (25 de septiembre de 2021): 8929. http://dx.doi.org/10.3390/app11198929.

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The laser projector based on the laser galvanometer scanning system enables the projection of CAD-based laser images onto geometrical objects. Furthermore, the system can perform a scan of components in order to control proper positioning (e.g., welded structures). We decided to conduct research aimed at determining the suitability of such systems for length measurements and assess their accuracy. These systems are commonly calibrated with the use of flat calibration boards, although their capability of projecting and scanning 3D objects. For this reason, a new method based on ISO 10360 has been proposed. Analysis of the system’s ability to perform length measurements, selection of a reference standard, and the tested device accuracy were the main objectives of the study. A ball-bar with a nominal length of 3000 mm was chosen as a reference standard. Positions of the reference element in the workspace were determined, and three series of five measured deviations were performed in each setting. The obtained values of measurement errors prove that it is possible to use ball-bar standards to assess the accuracy of the described systems, which is defined by the equation MPE(E0) = ±0.5 mm. The proposed method could be adapted to perform more complex analyzes in this area.

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42

German, Anna. "3D art cartography in Belarus: The historical development and achievements in the modern period". Abstracts of the ICA 1 (15 de julio de 2019): 1–2. http://dx.doi.org/10.5194/ica-abs-1-94-2019.

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Abstract. Three-dimensional images of the area were begun to create in the middle ages. The discoveries of new territories had led to the necessity of their mapping. On the perspective-panoramic maps of that time cities and fortresses were often depicted as they could be seen by an approaching traveler, usually from the most impressive side, from "bird's eye view". Cartographic images were performed manually, by the method of engraving on wood or on copper. One of the first panoramic maps of Belarusian cities was a cartographic image of the city of Grodno, presented in The Large Atlas of Cities called "Civitates Orbis Terrarum" ("Cities of the world"). The Atlas was published by the cartographer Georg Braun and engraver of maps Franz Hogenberg in Cologne in 1572–1617. The main method of presentation of the cities in it was a picture. A significant contribution to the development of cartography in Belarus was made by cartographer, artist, engraver and printer, the creator of the map of The Grand Duchy of Lithuania (1613) Tomasz Makowski. For many years Makowski were traveling all over the country and thoroughly studying its features as a topographer, historian, artist and geographer. He examined and sketched the most outstanding objects, as evidenced by his panoramic images of some cities. In particular, he created panoramic engravings of Nesvizh, Grodno, Brest and other cities of modern Belarus. Nowadays, the traditions of medieval art cartography in Belarus have received a new development in the works of artist-cartographer Ruben Atoyan. Initially, cartographic images were made manually with ink and watercolors. Panoramic maps of the main cities of Belarus, including Minsk, Grodno, Gomel, Mogilev, Mir, Nesvizh, Novogrudok, etc. were created in a such way. With the usage of computer technologies at the present stage, the technique of creating of artistic cartographic images has significantly changed. The majority of types of work which was performed previously by creating on paper, now is possible to implement using a personal computer, graphics tablet and vector and raster graphics programs. During this process – and it's very important – the handwritten style of images is kept and the ability of operative update of the content is provided. However, there are some types of artistic and cartographic work which easier and faster to accomplish manually than on the computer, for example, drawing of different types of trees, grasses, waters of rivers and lakes. In this case it's possible to speak about the combined handwriting-automated technology of artistic map image creation which includes elements made manually and the separated stages and elements which advisable to perform on the computer. The construction of the perspective image of an urban landscape according to the method developed by the author conditionally consists of several stages. The first step includes the selection of the projection direction and determination of the territory coverage by remote sensing images of the Earth and the city plan. The previously developed template of perspective (central) projection is used to build a perspective grid on the sheet of the drawing paper. Then the road network and configuration of the structures are drawn. The second stage is the construction of buildings’ frames of complex configuration (for example, architectural monuments) and drawing them in ink. The third stage includes the color design (with watercolor) of significant parkland, forests, and water areas. It was determined empirically that this type of work is more appropriate to perform manually. The handwritten component of this technique is completed by scanning of the image in high resolution. Further, the creation of a panoramic map is carried out with the usage of vector and raster graphics programs. The fourth stage involves the detailing of the facades, i.e. filling the frames with structural elements from the pre-created library of signs (different types of windows, doors, arches, balconies, etc.) (using the vector graphics program Adobe Illustrator). At the final, the fifth stage, the concluding color design of the panorama is realized according to the library of colors and textures (using the raster graphics program Adobe Photoshop). The similar steps are performed in graphic editors during the creating of a panoramic map using the automated technique. This method involves the usage of computer technologies only. Thus, at the first level of visualization the plan of the territory based on an aerial photograph of the city is created in the program Adobe Illustrator. Then this scheme is transformed into a perspective projection using the tool “Perspective Distort” in the Free transform toolset. The construction of all buildings’ frames (including structures of complex configuration) is also implemented in vector format with the tools "Pen" and "Line Segment" (the second level of visualization). At the third and fourth levels, the frames are filled with structural elements, and then the whole cartographic image is made in color according to the libraries of textures and colors. Operational updating of the content of panoramas created earlier is carried out mainly by the combined technique with the usage of Adobe Photoshop: new buildings which were drawn manually or on a computer are combined with the scanned original, the colors of facades and roofs are updated, park spaces and road junctions are added. For these purposes the following tools are used: "Polygonal Lasso", "Brush", "Clone Stamp", "Color Replacement ", – as well as the options "Curves", "Color Balance", "Hue/Saturation" of the section Image/Adjustment. The combined handwritten and automated method of constructing of three-dimensional cartographic images was tested by the author during the creating and updating of the panoramic maps of cities not only of Belarus, but also other world-class cities: Berlin, Moscow, Yerevan, Astana. Currently, the author is working on the practical usage of this method of creating of artistic cartographic images for the development of electronic multi-scale applications for the cities of the Republic of Belarus.

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43

Lapaine, Miljenko. "Local Linear Scale Factors in Map Projections of an Ellipsoid". Geographies 1, n.º 3 (9 de noviembre de 2021): 238–50. http://dx.doi.org/10.3390/geographies1030014.

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The main problem in cartography is that it is not possible to map/project/transform a spherical or ellipsoidal surface into a plane without distortions. The distortions of areas, angles, and/or distances are immanent to all maps. It is known that scale changes from point to point, and at certain points, the scale usually depends on the direction. The local linear scale factor c is one of the most important indicators of distortion distribution in the theory of map projections. It is not possible to find out the values of the local linear scale factor c in directions of coordinate axes x and y immediately from the definition of c. To solve this problem, in this paper, we derive new formulae for the calculation of c for a rotational ellipsoid. In addition, we derive the formula for computing c in any direction defined by dx and dy. We also considered the position and magnitude of the extreme values of c and derived new formulae for a rotational ellipsoid.

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44

Gastner, Michael T., Vivien Seguy y Pratyush More. "Fast flow-based algorithm for creating density-equalizing map projections". Proceedings of the National Academy of Sciences 115, n.º 10 (20 de febrero de 2018): E2156—E2164. http://dx.doi.org/10.1073/pnas.1712674115.

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Cartograms are maps that rescale geographic regions (e.g., countries, districts) such that their areas are proportional to quantitative demographic data (e.g., population size, gross domestic product). Unlike conventional bar or pie charts, cartograms can represent correctly which regions share common borders, resulting in insightful visualizations that can be the basis for further spatial statistical analysis. Computer programs can assist data scientists in preparing cartograms, but developing an algorithm that can quickly transform every coordinate on the map (including points that are not exactly on a border) while generating recognizable images has remained a challenge. Methods that translate the cartographic deformations into physics-inspired equations of motion have become popular, but solving these equations with sufficient accuracy can still take several minutes on current hardware. Here we introduce a flow-based algorithm whose equations of motion are numerically easier to solve compared with previous methods. The equations allow straightforward parallelization so that the calculation takes only a few seconds even for complex and detailed input. Despite the speedup, the proposed algorithm still keeps the advantages of previous techniques: With comparable quantitative measures of shape distortion, it accurately scales all areas, correctly fits the regions together, and generates a map projection for every point. We demonstrate the use of our algorithm with applications to the 2016 US election results, the gross domestic products of Indian states and Chinese provinces, and the spatial distribution of deaths in the London borough of Kensington and Chelsea between 2011 and 2014.

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45

Kühlbrandt, Werner. "Image Processing of Thin Three-Dimensional Crystals of the Light-Harvesting Chlorophyll a/b-Protein Complex from Chloroplast Membranes". Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 148–49. http://dx.doi.org/10.1017/s0424820100102821.

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Thin three-dimensional, hexagonal crystals of the light—harvesting chlorophyll a/b—protein complex (LHC II) from pea chloroplast membranes diffract electrons to 3.7 Å resolution when preserved in glucose or tannin. The symmetry of the diffraction pattern (6mm), the dimensions of the unit cell in projection (a = 127 Å) and micrographs of negatively stained specimens suggested that the hexagonal crystals were stacks of two-dimensional crystals of p321 symmetry. Low—dose (1 —2 electrons/Å2) electron micrographs of thin three-dimensional crystals preserved in tannin were recorded in an attempt to determine the structure of this integral membrane protein complex at high resolution, initially in projection. The best images showed sharp diffraction spots at 12 — 14 Å resolution when examined by optical diffraction. Image areas measuring up to 40 x 40 mm2 were densitometered at a step size corresponding to 3 Å or less at the specimen and computer processed to correct for lattice distortions, using programmes by R.Henderson and J.M.Baldwin. Fourier transforms of the distortion—corrected images showed reflections above background level to 6 Å resolution.

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46

Baruzdin, S. A. "RESOLVING POWER OF MODIFIED IMAGE RECONSTRUCTION METHOD IN SPIN DENSITY PROJECTIONS IN MAGNETIC RESONANCE IMAGING". Journal of the Russian Universities. Radioelectronics, n.º 1 (28 de febrero de 2019): 75–83. http://dx.doi.org/10.32603/1993-8985-2019-22-1-75-83.

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The well-known method of image reconstruction by projections in magnetic resonance imaging uses spin echo excited by two sinc pulses. The further processing involves forming of the spin echo signal two quadrature components converting them into a digital format and the subsequent Fourier transform. The proposed modified method is based on the second sinc radio pulse substitution for the linear FM pulse. In this case, the mentioned projections are formed by amplitude detection of the spin echo envelope, which significantly simplifies the processing procedure. The aim of the research is to analyze the modified method resolution. The mathematical model is based on Bloch equations. Their solution is carried out on the basis of the device of the spin system state transition matrices. For their calculation, the stepped approximation of the excitation pulse complex envelopes is used. It makes possible to convert the system of linear differential equations with variable coefficients (Bloch equations) to the system of linear differential equations with piecewise constant coefficients. In this case, the equations have analytical solution. Following the obtained solution, the analysis of the method resolution not previously investigated, is performed by means of modeling the spin echo excitation. The conditions are specified when no dynamic distortions influencing received image quality exist. It is shown that resolution is determined by the size of the scan area, the magnitude of the gradient of the applied magnetic field, the pulse duration with linear frequency modulation, as well as gyromagnetic ratio of the core type used. The developed method eliminates the need for Fourier transform over the spin echo signal and pro-vides resolution comparable to the conventional one.

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47

Zhang, Hao, Haifu Wang, Qingbo Yu, Yuanfeng Zheng, Guancheng Lu y Chao Ge. "Perforation of Double-Spaced Aluminum Plates by Reactive Projectiles with Different Densities". Materials 14, n.º 5 (5 de marzo de 2021): 1229. http://dx.doi.org/10.3390/ma14051229.

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Perforation behavior of 3 mm/3 mm double-spaced aluminum plates by PTFE/Al/W (Polytetrafluoroethylene/Aluminum/Tungsten) reactive projectiles with densities ranging from 2.27 to 7.80 g/cm3 was studied experimentally and theoretically. Ballistic experiments show that the failure mode of the front plate transforms from petalling failure to plugging failure as projectile density increases. Theoretical prediction of the critical velocities for the reactive projectiles perforating the double-spaced plates is proposed, which is consistent with the experimental results and well represents the perforation performance of the projectiles. Dimensionless formulae for estimating the perforation diameter and deflection height of the front plates are obtained through dimensional analysis, indicating material density and strength are dominant factors to determine the perforation size. High-speed video sequences of the perforation process demonstrate that high-density reactive projectiles make greater damage to the rear plates because of the generation of projectile debris streams. Specifically, the maximum spray angle of the debris streams and the crater number in the debris concentration area of the rear plate both increase with the projectile density and initial velocity.

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48

Wu, Tinghui, Jian Yu, Jingxia Lu, Xiuguo Zou y Wentian Zhang. "Research on Inversion Model of Cultivated Soil Moisture Content Based on Hyperspectral Imaging Analysis". Agriculture 10, n.º 7 (13 de julio de 2020): 292. http://dx.doi.org/10.3390/agriculture10070292.

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Based on hyperspectral imaging technology, rapid and efficient prediction of soil moisture content (SMC) can provide an essential basis for the formulation of precise agricultural programs (e.g., forestry irrigation and environmental management). To build an efficient inversion model of SMC, this paper collected 117 cultivated soil samples from the Chair Hill area and tested them using the GaiaSorter hyperspectral sorter. The collected soil reflectance dataset was preprocessed by wavelet transform, before the combination of competitive adaptive reweighted sampling algorithm and successive projections algorithm (CARS-SPA) was used to select the bands optimally. Seven wavelengths of 695, 711, 736, 747, 767, 778, and 796 nm were selected and used as the factors of the SMC inversion model. The popular linear regression algorithm was employed to construct this model. The result indicated that the inversion model established by the multiple linear regression algorithm (the predicted R2 was 0.83 and the RMSE was 0.0078) was feasible and highly accurate, indicating it could play an important role in predicting SMC of cultivated soils over a large area for agricultural irrigation and remote monitoring of crop yields.

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49

Sui, Yu-Tong, Shuai Li, Fu-Ren Ming y A.-Man Zhang. "An experimental study of the water entry trajectories of truncated cone projectiles: The influence of nose parameters". Physics of Fluids 34, n.º 5 (mayo de 2022): 052102. http://dx.doi.org/10.1063/5.0089366.

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We report on an experimental study of the trajectories of truncated cone projectiles on water entry. The water entry trajectory stability is of great significance to the motion control of projectile. In this paper, the truncated cone nose shape can be described by the area of the leading plane and the cone angle α. Two high-speed cameras are used to capture the trajectories of the projectiles and the initial stage of cavity dynamics. We reveal that the trajectory stability of a projectile is highly dependent on the wetted surface of the nose, which is determined by the location of the separation line between the surfaces of the cavity and body. The increase in the leading plane area is beneficial to the formation of a stable trajectory, in which only the leading plane is wetted. In an unstable trajectory case, the large hydrodynamic moment from the wetted surface on the side of the nose causes a significant rotation of the projectile. However, for the projectile with the cone angle [Formula: see text], though the side of the nose is fully wetted, the trajectory of the projectile turns into stable again. Results show that the attitude deflection of the projectile is determined by the cone angle of the nose. It is also found that the attitude deflection results in an irregular cavity, which further aggravates the rotation of the projectile. We quantify the relationship between the trajectory stability and two nose parameters systematically, and a phase diagram is obtained for a large parameter space. The findings in this work can be used as a reference for future designs to ensure stable trajectories on water entry.

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50

Jiang, Guo, Shuguang Zhou, Shichao Cui, Tao Chen, Jinlin Wang, Xi Chen, Shibin Liao y Kefa Zhou. "Exploring the Potential of HySpex Hyperspectral Imagery for Extraction of Copper Content". Sensors 20, n.º 21 (6 de noviembre de 2020): 6325. http://dx.doi.org/10.3390/s20216325.

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Detritus geochemical information has been proven through research to be an effective prospecting method in mineral exploration. However, the traditional detritus metal content monitoring methods based on field sampling and laboratory chemical analysis are time-consuming and may not meet the requirements of large-scale metal content monitoring. In this study, we obtained 95 detritus samples and seven HySpex hyperspectral imagery scenes with a spatial resolution of 1 m from Karatag Gobi area, Xinjiang, China, and used partial least squares and wavebands selection methods to explore the usefulness of super-low-altitude HySpex hyperspectral images in estimating detritus feasibility and effectiveness of Cu element content. The results show that: (1) among all the inversion models of transformed spectra, power-logarithm transformation spectrum was the optimal prediction model (coefficient of determination(R2) = 0.586, mean absolute error(MAE) = 21.405); (2) compared to the genetic algorithm (GA) and continuous projection algorithm (SPA), the competitive weighted resampling algorithm (CARS) was the optimal feature band-screening method. The R2 of the inversion model was constructed based on the characteristic bands selected by CARS reaching 0.734, which was higher than that of GA (0.519) and SPA (0.691), and the MAE (19.926) was the lowest. Only 20 bands were used in the model construction, which is lower than that of GA (105) and SPA (42); (3) The power-logarithm transforms, and CARS combined with the model of HySpex hyperspectral images and the Cu content distribution in the study area were obtained, consistent with the actual survey results on the ground. Our results prove that the method incorporating the HySpex hyperspectral data to invert copper content in detritus is feasible and effective, and provides data and a reference method for obtaining geochemical element distribution in a large area and for reducing key areas of geological exploration in the future.

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