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1
Bohner, Lauren, Daniel Habor, Klaus Radermacher, Stefan Wolfart e Juliana Marotti. "Scanning of a Dental Implant with a High-Frequency Ultrasound Scanner: A Pilot Study". Applied Sciences 11, n. 12 (14 giugno 2021): 5494. http://dx.doi.org/10.3390/app11125494.
Testo completoAbstract (sommario):
The purpose of this in vitro study was to assess the trueness of a dental implant scanned using an intraoral high-frequency ultrasound prototype and compared with conventional optical scanners. An acrylic resin cast containing a dental implant at position 11 was scanned with a fringe projection 3D sensor for use as a reference dataset. The same cast was scanned 10 times for each group. Ultrasound scanning was performed with a high-frequency probe (42 MHz, aperture diameter of 4 mm and focus length of 8 mm), and 3D images were reconstructed based on the depth of each surface point echo. Optical scans were performed in a laboratory and with an intraoral scanner. A region of interest consisting of the dental implant site was segmented and matched to the reference dataset. Trueness was defined as the closeness between experimental data and the reference surface. Statistical analysis was performed with one-way ANOVA and post-hoc tests with a significance level of p = 0.05. No statistical difference was found among the evaluated scanners. The mean deviation error was 57.40 ± 17.44 µm for the ultrasound scanner, 75.40 ± 41.43 µm for the laboratory scanner and 38.55 ± 24.34 µm for the intraoral scanner. The high-frequency ultrasound scanner showed similar trueness to optical scanners for digital implant impression.
2
Ruzgienė, Birutė, Renata Bagdžiūnaitė e Vilma Ruginytė. "SCANNING AERIAL PHOTOS USING A NON-PROFESSIONAL SCANNER". Geodesy and Cartography 38, n. 3 (1 ottobre 2012): 118–21. http://dx.doi.org/10.3846/20296991.2012.728901.
Testo completoAbstract (sommario):
For scanning analog aerial photographs, digital photogrammetry requires specific and expensive photogrammetric scanners. However, we only have a simple A4 format scanner useful for solving some special photogrammetric tasks applied for analyzing the possibilities of scanning photographic material. The paper investigates the peculiarities of scanning analog aerial photos using the scanner processing pictures smaller than an A4 format. The achieved results are compared with digital data obtained using a professional photogrammetric scanner. Experimental photogrammetric measurements have showed that the results of aerial photographs scanned by a nonprofessional scanner satisfy accuracy requirements for topographic mapping at a scale of 1:5000.
3
Rabah, Chaima Ben, Gouenou Coatrieux e Riadh Abdelfattah. "Boosting up Source Scanner Identification Using Wavelets and Convolutional Neural Networks". Traitement du Signal 37, n. 6 (31 dicembre 2020): 881–88. http://dx.doi.org/10.18280/ts.370601.
Testo completoAbstract (sommario):
In this paper, we present a conceptually innovative method for source scanner identification (SSI), that is to say, identifying the scanner at the origin of a scanned document. Solutions from literature can distinguish between scanners of different brands and models but fail to differentiate between scanners of the same models. To overcome this issue, the approach we propose takes advantage of a convolutional neural network (CNN) to automatically extract intrinsic scanner features from the distribution of the coefficients of the diagonal high-frequency (HH) sub-band of the discrete stationary wavelet transform (SWT) of scanned images. Such information serves as a reliable characteristic to classify scanners of different/same brands and models. Experiments conducted on a set of 8 scanners yielded a model with an accuracy of 99.31% at the block level and 100% at the full image level, showcasing the potential of using deep learning for SSI and outperforming existing schemes from literature. The influence of the model’s parameters such as the input size, the training data size, the number of layers, and the number of nodes in the fully connected layer as well as the effect of the pre-processing step were investigated.
4
Nestle, U., S. Kremp, D. Hellwig, A. Grgic, H. G. Buchholz, W. Mischke, C. Gromoll et al. "Multi-centre calibration of an adaptive thresholding method for PET-based delineation of tumour volumes in radiotherapy planning of lung cancer". Nuklearmedizin 51, n. 03 (2012): 101–10. http://dx.doi.org/10.3413/nukmed-0452-11-12.
Testo completoAbstract (sommario):
SummaryPurpose: To evaluate the calibration of an adaptive thresholding algorithm (contrastoriented algorithm) for FDG PET-based delineation of tumour volumes in eleven centres with respect to scanner types and image data processing by phantom measurements. Methods: A cylindrical phantom with spheres of different diameters was filled with FDG realizing different signal-to-background ratios and scanned using 5 Siemens Biograph PET/CT scanners, 5 Philips Gemini PET/CT scanners, and one Siemens ECAT-ART PET scanner. All scans were analysed by the contrast-oriented algorithm implemented in two different software packages. For each site, the threshold SUVs of all spheres best matching the known sphere volumes were determined. Calibration parameters a and b were calculated for each combination of scanner and image-analysis software package. In addition, “scanner-typespecific” calibration curves were determined from all values obtained for each combination of scanner type and software package. Both kinds of calibration curves were used for volume delineation of the spheres. Results: Only minor differences in calibration parameters were observed for scanners of the same type (Δa ≤ 4%, Δb ≤ 14%) provided that identical imaging protocols were used whereas significant differences were found comparing calibration parameters of the ART scanner with those of scanners of different type (Δa ≤ 60%, Δb ≤ 54%). After calibration, for all scanners investigated the calculated SUV thresholds for auto-contouring did not differ significantly (all p > 0.58). The resulting sphere volumes deviated by less than –7% to +8% from the true values. Conclusion: After multi-centre calibration the use of the contrast-oriented algorithm for FDG PET-based delineation of tumour volumes in the different centres using different scanner types and specific imaging protocols is feasible.
5
Stangeland, Marcus, Trond Engjom, Martin Mezl, Radovan Jirik, Odd Gilja, Georg Dimcevski e Kim Nylund. "Interobserver Variation of the Bolus-and-Burst Method for Pancreatic Perfusion with Dynamic – Contrast-Enhanced Ultrasound". Ultrasound International Open 03, n. 03 (giugno 2017): E99—E106. http://dx.doi.org/10.1055/s-0043-110475.
Testo completoAbstract (sommario):
Abstract Purpose Dynamic contrast-enhanced ultrasound (DCE-US) can be used for calculating organ perfusion. By combining bolus injection with burst replenishment, the actual mean transit time (MTT) can be estimated. Blood volume (BV) can be obtained by scaling the data to a vessel on the imaging plane. The study aim was to test interobserver agreement for repeated recordings using the same ultrasound scanner and agreement between results on two different scanner systems. Materials and Methods Ten patients under evaluation for exocrine pancreatic failure were included. Each patient was scanned two times on a GE Logiq E9 scanner, by two different observers, and once on a Philips IU22 scanner, after a bolus of 1.5 ml Sonovue. A 60-second recording of contrast enhancement was performed before the burst and the scan continued for another 30 s for reperfusion. We performed data analysis using MATLAB-based DCE-US software. An artery in the same depth as the region of interest (ROI) was used for scaling. The measurements were compared using the intraclass correlation coefficient (ICC) and Bland Altman plots. Results The interobserver agreement on the Logiq E9 for MTT (ICC=0.83, confidence interval (CI) 0.46–0.96) was excellent. There was poor agreement for MTT between the Logiq E9 and the IU22 (ICC=−0.084, CI −0.68–0.58). The interobserver agreement for blood volume measurements was excellent on the Logiq E9 (ICC=0.9286, CI 0.7250–0.98) and between scanners (ICC=0.86, CI=0.50–0.97). Conclusion Interobserver agreement was excellent using the same scanner for both parameters and between scanners for BV, but the comparison between two scanners did not yield acceptable agreement for MTT. This was probably due to incomplete bursting of bubbles in some of the recordings on the IU22.
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Provenzale, James M., Brian A. Taylor, Elisabeth A. Wilde, Michael Boss e Walter Schneider. "Analysis of variability of fractional anisotropy values at 3T using a novel diffusion tensor imaging phantom". Neuroradiology Journal 31, n. 6 (24 luglio 2018): 581–86. http://dx.doi.org/10.1177/1971400918789383.
Testo completoAbstract (sommario):
We employed a novel diffusion tensor imaging phantom to study intra- and interscanner reproducibility on two 3T magnetic resonance (MR) scanners. Using a phantom containing thousands of hollow micron-size tubes in complex arrays, we performed two experiments using a b value of 1000 s/ms2 on two Siemens 3T Trio scanners. First, we performed 12-direction scans. Second, on one scanner, we performed two 64-direction protocols with different repetition times (TRs). We used a one-way analysis of variance to calculate differences between scanners and the Mann-Whitney U test to assess differences between 12-direction and 64-direction data. We calculated the coefficient of variation (CoV) for intrascanner and interscanner data. For 12-direction protocols, mean fractional anisotropy (FA) was 0.3003 for Scanner 1 (four scans) and 0.3094 for Scanner 2 (three scans). Lowest FA value on Scanner 1 was 2.56 standard deviations below the mean of Scanner 2. For 64-direction scans, mean FA was 0.2640 for 4000 ms TR and 0.2582 for 13,200 ms TR scans. For 12-direction scans, within-scanner CoV was 0.0326 for Scanner 1 and 0.0240 for Scanner 2; between-scanner CoV was 0.032. For 64-direction scans, CoV was 0.056 for TR 4000 ms and 0.0533 for TR 13,200 ms. The difference between median FA values of 12-direction and 64-direction scans was statistically significant ( p < 0.001). We found relatively good reproducibility on any single MR scanner. FA values from one scanner were sometimes significantly below the mean FA of another scanner, which has important implications for clinical use of DTI.
7
Xu, Ji Hong, Xiao Lin Dai e Shu Ping Gao. "A Study on Data Acquisition from Sections of Virtual Coat Profile". Advanced Materials Research 230-232 (maggio 2011): 1204–9. http://dx.doi.org/10.4028/www.scientific.net/amr.230-232.1204.
Testo completoAbstract (sommario):
Data was obtained through scanning manikin and coats separated by using [TC]2 3D body scanner. The method, using [TC]2 scanner as the experimental method and through double converting the scanned data format to get torso geometric section sets, was analyzed. Main program source code of Torso was provided in this paper. Geometric algorithms of point cloud data and curve data in there sections was provided based on the interception ways of horizontal sections, vertical sections and other random oblique sections toward torso geometric cross section.
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Chen, Kai, Kai Zhan, Xiaocong Yang e Da Zhang. "Accuracy Improvement Method of a 3D Laser Scanner Based on the D-H Model". Shock and Vibration 2021 (25 maggio 2021): 1–9. http://dx.doi.org/10.1155/2021/9965904.
Testo completoAbstract (sommario):
A three-dimensional (3D) laser scanner with characteristics such as acquiring huge point cloud data and noncontact measurement has revolutionized the surveying and mapping industry. Nonetheless, how to guarantee the 3D laser scanner precision remains the critical factor that determines the excellence of 3D laser scanners. Hence, this study proposes a 3D laser scanner error analysis and calibration-method-based D-H model, applies the D-H model method in the robot area to the 3D laser scanner coordinate for calculating the point cloud data and creatively derive the error model, comprehensively analyzes six external parameters and seven inner structure parameters that affect point cloud coordinator error, and designs two calibration platforms for inner structure parameters. To validate the proposed method, we used SOKKIA total station and BLSS-PE 3D laser scanner to attain the center coordinate of the testing target sphere and then evaluate the external parameters and modify the point coordinate. Based on modifying the point coordinate, comparing the point coordinate that considered the inner structure parameters with the point coordinate that did not consider the inner structure parameters, the experiment revealed that the BLSS-PE 3D laser scanner’s precision enhanced after considering the inner structure parameters, demonstrating that the error analysis and calibration method was correct and feasible.
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Elbrecht, Pirjo, Jaak Henno e Knut Joosep Palm. "Body Measurements Extraction from 3D Scanner Data". Applied Mechanics and Materials 339 (luglio 2013): 372–77. http://dx.doi.org/10.4028/www.scientific.net/amm.339.372.
Testo completoAbstract (sommario):
The growing power of computing, development of methods of 3D graphics for human body modeling and simulation together with development of 3D image capture technologies using 3D scanners has caused rapid development of digital tailoring - a complex of methods where made-to-measure clothing is produced starting with 3D scanning of a customer, extraction of essential measurements from obtained data cloud and then automatic production of a garment corresponding to exact measures of the customer. Extraction of exact measures from the ca 200000 data points produced by 3D scanner is a complex problem and not yet well investigated.
10
Liebold, F., e H. G. Maas. "Integrated Georeferencing of LiDAR and Camera Data Acquired from a Moving Platform". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-3 (11 agosto 2014): 191–96. http://dx.doi.org/10.5194/isprsarchives-xl-3-191-2014.
Testo completoAbstract (sommario):
This paper presents an approach for modeling the trajectory of a moving platform equipped with a laser scanner and a camera. In most cases, GNSS and INS is used to determine the orientation of the platform, but sometimes it is impossible to use GNSS, especially indoor applications should be mentioned here. INS has a bad error propagation without GNSS. In addition, the accuracy of GNSS and low-cost INS is limited and often not equivalent to the accuracy potential of laser scanners. For the camera, there exists the well-known alternative to obtain the orientation parameters via triangulation, for instance employing structure-from-motion techniques. But it is more challenging to find an alternative for the laser scanner, because of its sequential data acquisition. In the approach shown here, we propose to use a camera in combination with structure-from-motion techniques as the basis for determining the laser scanner trajectory parameters. For that purpose, we use piece-wise models for the trajectory through polynomial functions, supported by time-stamped matches between laser scanner and camera data.
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Im, Chang-Hee, Ji-Man Park, Jang-Hyun Kim, You-Jung Kang e Jee-Hwan Kim. "Assessment of Compatibility between Various Intraoral Scanners and 3D Printers through an Accuracy Analysis of 3D Printed Models". Materials 13, n. 19 (4 ottobre 2020): 4419. http://dx.doi.org/10.3390/ma13194419.
Testo completoAbstract (sommario):
To assess the accuracy of various intraoral scanners (IOSs) and to investigate the existence of mutual compatibility that affects the accuracy between IOS and 3-dimensional (3D) printing using a scan quadrant model. For clinical implication, crown preparations and cavity design according to prosthetic diagnosis and treatment considerations must be acquired by a digital scanner. The selected typodont model was scanned using a reference scanner, from which reference (Ref) standard tessellation language (STL) data were created. Data obtained by scanning the typodont model with IOSs based on three different technologies were divided into three groups (CS3600, i500, and Trios3). Scanned data from the groups were divided into sub-groups of digital light processing (DLP), fused deposition modeling (FDM), and stereolithography apparatus (SLA), based on which 3D printed models (3DP) were fabricated. The 3DP dental models were scanned to obtain a total of 90 3DP STL datasets. The best-fit algorithm of 3D analysis software was used for teeth and arch measurements, while trueness was analyzed by calculating the average deviation among measured values based on superimposition of Ref and IOS and 3DP data. The differences between Ref and IOS (Ref-IOS), Ref and 3DP (Ref-IOS/3DP), and IOS and 3DP data (IOS-3DP) were compared and analyzed, while accuracy within each of the three main groups was assessed. For statistical analysis, the Kruskal–Wallis, Mann–Whitney U, and repeated measures ANOVA test were used (p < 0.05). The major finding is that the mutual relationships between IOSs and 3D printers vary depending on the combination. However, i500 intraoral scanner and DLP 3D printer was the combination that showed the best trueness value.
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Todo, Chikage, Hidetoshi Ikeno, Keitaro Yamase, Toko Tanikawa, Mizue Ohashi, Masako Dannoura, Toshifumi Kimura e Yasuhiro Hirano. "Reconstruction of Conifer Root Systems Mapped with Point Cloud Data Obtained by 3D Laser Scanning Compared with Manual Measurement". Forests 12, n. 8 (21 agosto 2021): 1117. http://dx.doi.org/10.3390/f12081117.
Testo completoAbstract (sommario):
Three-dimensional (3D) root system architecture (RSA) is a predominant factor in anchorage failure in trees. Only a few studies have used 3D laser scanners to evaluate RSA, but they do not check the accuracy of measurements. 3D laser scanners can quickly obtain RSA data, but the data are collected as a point cloud with a large number of points representing surfaces. The point cloud data must be converted into a set of interconnected axes and segments to compute the root system traits. The purposes of this study were: (i) to propose a new method for easily obtaining root point data as 3D coordinates and root diameters from point cloud data acquired by 3D laser scanner measurement; and (ii) to compare the accuracy of the data from main roots with intensive manual measurement. We scanned the excavated root systems of two Pinus thunbergii Parl. trees using a 3D laser scanner and neuTube software, which was developed for reconstructing the neuronal structure, to convert the point cloud data into root point data for reconstructing RSA. The reconstruction and traits of the RSA calculated from point cloud data were similar in accuracy to intensive manual measurements. Roots larger than 7 mm in diameter were accurately measured by the 3D laser scanner measurement. In the proposed method, the root point data were connected as a frustum of cones, so the reconstructed RSAs were simpler than the 3D root surfaces. However, the frustum of cones still showed the main coarse root segments correctly. We concluded that the proposed method could be applied to reconstruct the RSA and calculate traits using point cloud data of the root system, on the condition that it was possible to model both the stump and ovality of root sections.
13
Nam, Na-Eun, Seung-Ho Shin, Jung-Hwa Lim, Bora Lee, June-Sung Shim e Jong-Eun Kim. "Accuracy of Implant Position Reproduction According to Exposed Length of the Scan Body during Optical Scanning: An In Vitro Study". Applied Sciences 11, n. 4 (13 febbraio 2021): 1689. http://dx.doi.org/10.3390/app11041689.
Testo completoAbstract (sommario):
Accuracy of implant position reproduction according to various types of scanners, implant placement depths, and tooth positions are unknown. The purpose of this study was to compare the accuracy of implant position reproduction for differences in the exposed length of the implant scan body according to scanner type and tooth position. Implants were placed at the positions of the lateral incisor, first premolar, and first molar in the study model at the bone level and submerged 1.5 mm, 3.0 mm, 4.5 mm, and 6.0 mm. The completed models were scanned with one type of tabletop scanner and three types of intraoral scanners (TRIOS 3, i500, and CS3600). A matching process was performed for all scan data to superimpose abutment library data on the scan body, and the root mean square errors were analyzed in three dimensions to evaluate the position reproducibility of the replaced abutment library. In the trueness analysis, the error increased rapidly for an implant placement depth of 4.5 mm, and was largest for a submersion of 6.0 mm. The precision analysis confirmed that the error increased for depths of at least 3.0 mm. The analysis by position identified that the accuracy was lowest for an implant placed at the position of the lateral incisor. These findings indicate that special care is required when making an impression of a deep implant with an optical scanner.
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Baron, Steve, e Andrew Lock. "The Challenges of Scanner Data". Journal of the Operational Research Society 46, n. 1 (gennaio 1995): 50. http://dx.doi.org/10.2307/2583835.
Testo completo
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Baron, Steve, e Andrew Lock. "The Challenges of Scanner Data". Journal of the Operational Research Society 46, n. 1 (gennaio 1995): 50–61. http://dx.doi.org/10.1057/jors.1995.6.
Testo completo
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Vu, T. Thuy, e Mitsuharu Tokunaga. "Filtering Airborne Laser Scanner Data". Photogrammetric Engineering & Remote Sensing 70, n. 11 (1 novembre 2004): 1267–74. http://dx.doi.org/10.14358/pers.70.11.1267.
Testo completo
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Biedl, Therese, Stephane Durocher e Jack Snoeyink. "Reconstructing polygons from scanner data". Theoretical Computer Science 412, n. 32 (luglio 2011): 4161–72. http://dx.doi.org/10.1016/j.tcs.2010.10.026.
Testo completo
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Komissarov, A. V., A. V. Remizov, M. M. Shlyakhova e K. K. Yambaev. "Handheld Laser Scanner Research". Geodesy and Cartography 952, n. 10 (20 novembre 2019): 47–54. http://dx.doi.org/10.22389/0016-7126-2019-952-10-47-54.
Testo completoAbstract (sommario):
The authors consider hand-held laser scanners, as a new photogrammetric tool for obtaining three-dimensional models of objects. The principle of their work and the newest optical systems based on various sensors measuring the depth of space are described in detail. The method of simultaneous navigation and mapping (SLAM) used for combining single scans into point cloud is outlined. The formulated tasks and methods for performing studies of the DotProduct (USA) hand-held laser scanner DPI?8X based on a test site survey are presented. The accuracy requirements for determining the coordinates of polygon points are given. The essence of the performed experimental research of the DPI?8X scanner is described, including scanning of a test object at various scanner distances, shooting a test polygon from various scanner positions and building point cloud, repeatedly shooting the same area of the polygon to check the stability of the scanner. The data on the assessment of accuracy and analysis of research results are given. Fields of applying hand-held laser scanners, their advantages and disadvantages are identified.
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Heinzel, J., e M. O. Huber. "TLS FIELD DATA BASED INTENSITY CORRECTION FOR FOREST ENVIRONMENTS". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (23 giugno 2016): 643–49. http://dx.doi.org/10.5194/isprs-archives-xli-b8-643-2016.
Testo completoAbstract (sommario):
Terrestrial laser scanning (TLS) is increasingly used for forestry applications. Besides the three dimensional point coordinates, the 'intensity' of the reflected signal plays an important role in forestry and vegetation studies. The benefit of the signal intensity is caused by the wavelength of the laser that is within the near infrared (NIR) for most scanners. The NIR is highly indicative for various vegetation characteristics. <br><br> However, the intensity as recorded by most terrestrial scanners is distorted by both external and scanner specific factors. Since details about system internal alteration of the signal are often unknown to the user, model driven approaches are impractical. On the other hand, existing data driven calibration procedures require laborious acquisition of separate reference datasets or areas of homogenous reflection characteristics from the field data. <br><br> In order to fill this gap, the present study introduces an approach to correct unwanted intensity variations directly from the point cloud of the field data. The focus is on the variation over range and sensor specific distortions. Instead of an absolute calibration of the values, a relative correction within the dataset is sufficient for most forestry applications. Finally, a method similar to time series detrending is presented with the only pre-condition of a relative equal distribution of forest objects and materials over range. Our test data covers 50 terrestrial scans captured with a FARO Focus 3D S120 scanner using a laser wavelength of 905 nm. Practical tests demonstrate that our correction method removes range and scanner based alterations of the intensity.
20
Elbrecht, Pirjo, Jaak Henno e Knut Joosep Palm. "Waist Circumference Measurement Extraction from 3D Scanner Data". Advanced Materials Research 739 (agosto 2013): 725–31. http://dx.doi.org/10.4028/www.scientific.net/amr.739.725.
Testo completoAbstract (sommario):
The growing power of computing, development of methods of 3D graphics for human body modeling and simulation together with development of 3D image capture technologies using 3D scanners has caused rapid development of digital tailoring - a complex of methods where made-to-measure clothing is produced starting with 3D scanning of a customer, extraction of essential measurements from obtained data cloud and then automatic production of a garment corresponding to exact measures of the customer. Extraction of exact measures from the ca 200000 data points produced by 3D scanner is a complex problem; in the following are considered methods for solving waistline determination and waistline circumference measurement finding.
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Kedzierski, M., D. Wierzbickia, A. Fryskowska e B. Chlebowska. "ANALYSIS OF THE POSSIBILITIES OF USING LOW-COST SCANNING SYSTEM IN 3D MODELING". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B3 (9 giugno 2016): 261–67. http://dx.doi.org/10.5194/isprsarchives-xli-b3-261-2016.
Testo completoAbstract (sommario):
The laser scanning technique is still a very popular and fast growing method of obtaining information on modeling 3D objects. The use of low-cost miniature scanners creates new opportunities for small objects of 3D modeling based on point clouds acquired from the scan. The same, the development of accuracy and methods of automatic processing of this data type is noticeable. The article presents methods of collecting raw datasets in the form of a point-cloud using a low-cost ground-based laser scanner FabScan. As part of the research work 3D scanner from an open source FabLab project was constructed. In addition, the results for the analysis of the geometry of the point clouds obtained by using a low-cost laser scanner were presented. Also, some analysis of collecting data of different structures (made of various materials such as: glass, wood, paper, gum, plastic, plaster, ceramics, stoneware clay etc. and of different shapes: oval and similar to oval and prism shaped) have been done. The article presents two methods used for analysis: the first one - visual (general comparison between the 3D model and the real object) and the second one - comparative method (comparison between measurements on models and scanned objects using the mean error of a single sample of observations). The analysis showed, that the low-budget ground-based laser scanner FabScan has difficulties with collecting data of non-oval objects. Items built of glass painted black also caused problems for the scanner. In addition, the more details scanned object contains, the lower the accuracy of the collected point-cloud is. Nevertheless, the accuracy of collected data (using oval-straight shaped objects) is satisfactory. The accuracy, in this case, fluctuates between ± 0,4 mm and ± 1,0 mm whereas when using more detailed objects or a rectangular shaped prism the accuracy is much more lower, between 2,9 mm and ± 9,0 mm. Finally, the publication presents the possibility (for the future expansion of research) of modernization FabScan by the implementation of a larger amount of camera-laser units. This will enable spots the registration , that are less visible.
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Kedzierski, M., D. Wierzbickia, A. Fryskowska e B. Chlebowska. "ANALYSIS OF THE POSSIBILITIES OF USING LOW-COST SCANNING SYSTEM IN 3D MODELING". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B3 (9 giugno 2016): 261–67. http://dx.doi.org/10.5194/isprs-archives-xli-b3-261-2016.
Testo completoAbstract (sommario):
The laser scanning technique is still a very popular and fast growing method of obtaining information on modeling 3D objects. The use of low-cost miniature scanners creates new opportunities for small objects of 3D modeling based on point clouds acquired from the scan. The same, the development of accuracy and methods of automatic processing of this data type is noticeable. The article presents methods of collecting raw datasets in the form of a point-cloud using a low-cost ground-based laser scanner FabScan. As part of the research work 3D scanner from an open source FabLab project was constructed. In addition, the results for the analysis of the geometry of the point clouds obtained by using a low-cost laser scanner were presented. Also, some analysis of collecting data of different structures (made of various materials such as: glass, wood, paper, gum, plastic, plaster, ceramics, stoneware clay etc. and of different shapes: oval and similar to oval and prism shaped) have been done. The article presents two methods used for analysis: the first one - visual (general comparison between the 3D model and the real object) and the second one - comparative method (comparison between measurements on models and scanned objects using the mean error of a single sample of observations). The analysis showed, that the low-budget ground-based laser scanner FabScan has difficulties with collecting data of non-oval objects. Items built of glass painted black also caused problems for the scanner. In addition, the more details scanned object contains, the lower the accuracy of the collected point-cloud is. Nevertheless, the accuracy of collected data (using oval-straight shaped objects) is satisfactory. The accuracy, in this case, fluctuates between ± 0,4 mm and ± 1,0 mm whereas when using more detailed objects or a rectangular shaped prism the accuracy is much more lower, between 2,9 mm and ± 9,0 mm. Finally, the publication presents the possibility (for the future expansion of research) of modernization FabScan by the implementation of a larger amount of camera-laser units. This will enable spots the registration , that are less visible.
23
Heinzel, J., e M. O. Huber. "TLS FIELD DATA BASED INTENSITY CORRECTION FOR FOREST ENVIRONMENTS". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (23 giugno 2016): 643–49. http://dx.doi.org/10.5194/isprsarchives-xli-b8-643-2016.
Testo completoAbstract (sommario):
Terrestrial laser scanning (TLS) is increasingly used for forestry applications. Besides the three dimensional point coordinates, the 'intensity' of the reflected signal plays an important role in forestry and vegetation studies. The benefit of the signal intensity is caused by the wavelength of the laser that is within the near infrared (NIR) for most scanners. The NIR is highly indicative for various vegetation characteristics. <br><br> However, the intensity as recorded by most terrestrial scanners is distorted by both external and scanner specific factors. Since details about system internal alteration of the signal are often unknown to the user, model driven approaches are impractical. On the other hand, existing data driven calibration procedures require laborious acquisition of separate reference datasets or areas of homogenous reflection characteristics from the field data. <br><br> In order to fill this gap, the present study introduces an approach to correct unwanted intensity variations directly from the point cloud of the field data. The focus is on the variation over range and sensor specific distortions. Instead of an absolute calibration of the values, a relative correction within the dataset is sufficient for most forestry applications. Finally, a method similar to time series detrending is presented with the only pre-condition of a relative equal distribution of forest objects and materials over range. Our test data covers 50 terrestrial scans captured with a FARO Focus 3D S120 scanner using a laser wavelength of 905 nm. Practical tests demonstrate that our correction method removes range and scanner based alterations of the intensity.
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Hosseinyalamdary, S., e A. Yilmaz. "3D SUPER-RESOLUTION APPROACH FOR SPARSE LASER SCANNER DATA". ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences II-3/W5 (19 agosto 2015): 151–57. http://dx.doi.org/10.5194/isprsannals-ii-3-w5-151-2015.
Testo completoAbstract (sommario):
Laser scanner point cloud has been emerging in Photogrammetry and computer vision to achieve high level tasks such as object tracking, object recognition and scene understanding. However, low cost laser scanners are noisy, sparse and prone to systematic errors. This paper proposes a novel 3D super resolution approach to reconstruct surface of the objects in the scene. This method works on sparse, unorganized point clouds and has superior performance over other surface recovery approaches. Since the proposed approach uses anisotropic diffusion equation, it does not deteriorate the object boundaries and it preserves topology of the object.
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Maeng, Jiyoun, Young-Jun Lim, Bongju Kim, Myung-Joo Kim e Ho-Beom Kwon. "A New Approach to Accuracy Evaluation of Single-Tooth Abutment Using Two-Dimensional Analysis in Two Intraoral Scanners". International Journal of Environmental Research and Public Health 16, n. 6 (20 marzo 2019): 1021. http://dx.doi.org/10.3390/ijerph16061021.
Testo completoAbstract (sommario):
The aim of this study was to two-dimensionally evaluate deviation errors at five digital cross-sections of single-tooth abutment in regards to data obtained from two intraoral scanners, and to evaluate accuracy of individual scanners. Two intraoral scanners, the Trios 3® (3 Shape, Copenhagen, Denmark) and EzScan® (Vatech, Hwaseong, Korea), were evaluated by utilizing 13 stone models. The superimposed 3D data files were sectioned into five different planes: buccal-lingual section (BL), mesial-distal section (MD), transverse high section (TH), transverse middle section (TM), and transverse low section (TL). Accuracy comparison between the two scanners in 5 groups was performed. BL vs. MD of each scanner, and three transverse groups (TH, TM, TL) of each scanner were analyzed for accuracy comparison. In comparison of 2-D analyses for two intraoral scanners, Trios 3® showed statistically significant higher accuracy in root mean square (RMS) at BL, TH, and TL (p < 0.05). For each scanner, RMS value showed that mesial-distal sections were more prone to error than buccal-lingual section, which exhibited statistically significant errors (p < 0.05) while the transverse groups did not. Two-dimensional analysis is more insightful than three-dimensional analysis on single-tooth abutment. In mesiodistal areas, rough prepped areas, and sharp edges where scanner accessibility is difficult, high deviation errors are shown.
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Dědič, Martin. "3D scanning and analysis of acquired data of historically and culturally significant objects referring to the work of Adalbert Stifter". MATEC Web of Conferences 279 (2019): 01014. http://dx.doi.org/10.1051/matecconf/201927901014.
Testo completoAbstract (sommario):
The aim of the paper is to bring new findings from ongoing specific university research. Within this project, the light scanner scanned historically and culturally significant objects referring to the work of Czech-Austrian writer Adalbert Stifter in South Bohemia and Lower Austria. It also analyzed the data obtained with the light 3D scanner. The data was generated as a cloud of points. With respect to object´s size, multiple parts of each object were scanned individually. By combining individual scans and removing unwanted points (noise), models - digital twins of objects - were developed. Created models are valuable for their use for virtual tours of historically and culturally significant places. The final models were modified for printing on a 3D printer, where they were subsequently printed.
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Toś, Cezary. "The Possibilities of Using the Terrestrial Scanning Data for Classification of Rocks in Limestone Mine “Czatkowice”". Reports on Geodesy and Geoinformatics 97, n. 1 (3 febbraio 2015): 80–90. http://dx.doi.org/10.2478/rgg-2014-0013.
Testo completoAbstract (sommario):
AbstractThis paper presents results of a research of potential utilisation of the intensity of laser beam reflection recorded by ground-based lasers, for an initial classification of rock formations within the Czatkowice Limestone Quarry. As part of the research, spectrometric analysis in visible (VIS), near-infrared (NIR) and Short-wavelength infrared (SWIR) bands was carried out for rock samples typical for the Czatkowice Quarry. Moreover, the rock samples were scanned using equipment working within different wavelengths. The reflected intensity of the laser beam recorded for each rock sample with several different scanners were analysed to assess their potential use for rock classification. The results of this analysis were then compared with spectral curves of each sample. The relationship between the intensity of the laser beam reflection and the spectral curves can be used for selection of most suitable scanner for rock classification.
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Lee, Kyungmin Clara, e Seong-Joon Park. "Digital Intraoral Scanners and Alginate Impressions in Reproducing Full Dental Arches: A Comparative 3D Assessment". Applied Sciences 10, n. 21 (29 ottobre 2020): 7637. http://dx.doi.org/10.3390/app10217637.
Testo completoAbstract (sommario):
The purpose of this in vivo study was to compare in vivo full arch intraoral scans obtained using two intraoral scanners and conventional impression. Twenty patients were scanned using TRIOS and iTero scanners, as well as conventional impression. Dental models obtained from alginate impression were scanned with a laboratory desktop scanner. Individual intraoral scan data were compared with corresponding model scans using three-dimensional (3D) surface analysis. The average surface deviations were calculated for quantitative evaluation, and these values were compared between two intraoral scanners using the paired t-test. In the 3D surface analysis, most deviations between intraoral scans and model scans presented on the posterior teeth. The average surface deviations were less than 0.10 ± 0.03 mm. The results of 3D surface analysis indicated that there was 0.10 mm of overall deviation between conventional alginate impressions and in vivo full dental arch intraoral scans. Clinicians should take this into consideration when performing intraoral scanning for full dental arches.
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Foekens, Eijte W., e Peter S. H. Leeflang. "Comparing scanner data with traditional store audit data". Scandinavian International Business Review 1, n. 1 (gennaio 1992): 2. http://dx.doi.org/10.1016/0962-9262(92)90030-a.
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Foekens, Eijte W., e Peter S. H. Leeflang. "Comparing scanner data with traditional store audit data". Scandinavian International Business Review 1, n. 1 (gennaio 1992): 71–85. http://dx.doi.org/10.1016/0962-9262(92)90037-7.
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Štalmach, Ondrej, Alžbeta Sapietová, Vladimír Dekýš, Peter Šulka e Lukáš Gajdoš. "Conversion of data from the laser scanner to the Ansys Workbench". MATEC Web of Conferences 254 (2019): 02003. http://dx.doi.org/10.1051/matecconf/201925402003.
Testo completoAbstract (sommario):
This paper deals with the data processing in the form of a cloud of points scanned using a handheld 3D laser scanner. The aim of this paper is to use this data to create a representative FEM model and compare two different approaches while one of them involves creating a CAD model and the other one not. The data processing is carried out in the freeware systems MeshLab and Meshmixer and FEM analysis in the software ANSYS Workbench.
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Hedges, Emily, Jenny Zinser, Mihail Dimitrov, Mathilde Antoniades, Lilla Porffy, Sara Pisani, Hannah Dickson, Philip McGuire e Matthew J. Kempton. "M154. INTRA- AND INTER-SCANNER RELIABILITY OF GRAY MATTER VOLUME AND CORTICAL THICKNESS ESTIMATES: IMPLICATIONS FOR MULTICENTRE IMAGING STUDIES IN PSYCHOSIS". Schizophrenia Bulletin 46, Supplement_1 (aprile 2020): S194. http://dx.doi.org/10.1093/schbul/sbaa030.466.
Testo completoAbstract (sommario):
Abstract Background High-resolution structural MRI has been widely used in clinical research to detect and quantify subtle brain changes in patient populations. Findings from prospective, longitudinal studies show structural brain abnormalities as well as progressive gray matter changes over time in individuals at clinical high risk for psychosis compared to healthy subjects. In recent years, research in this field has seen an increase in multicentre neuroimaging projects, such as EU-GEI, PSYSCAN, PRONIA and NAPLS. Additional sources of variance, alongside known technological and biological factors, may be introduced when MRI images are acquired and combined from different sites. It is imperative for longitudinal multicentre studies to determine the accuracy of quantitative MRI measurements and account for systematic differences both between scanners and across scanning sessions. This is particularly true within psychosis research where morphometric changes as small as 3% or less are expected. Methods Six healthy participants were scanned on four separate occasions over a two-month period at King’s College London; twice on a GE SIGNA HDx 3T scanner used locally in the EU-GEI High Risk Study and twice on a GE MR750 3T scanner used locally in the PSYSCAN study. Both scanners implemented the ADNI-2 T1 protocol which is used globally across the EU-GEI and PSYSCAN consortia. Structural imaging data was segmented using the FreeSurfer 6.0 longitudinal pipeline. Intraclass correlation coefficients (ICCs) with a two-way mixed effects model of absolute agreement were calculated to assess intra- and inter-scanner reliability of brain morphometry. For volumetric studies, ICC values greater than 0.9 indicate ‘excellent’ reliability. Reliability analyses of key regions implicated in psychosis included gray matter volume estimates of the hippocampus, insula, lateral ventricle, orbitofrontal cortex and anterior cingulate cortex, and average cortical thickness measurements of the whole brain, parahippocampus and superior frontal cortex. Results Gray matter volume estimates of all structures yielded ‘excellent’ reliability for both intra-scanner (ICCs of 0.979 – 0.998) and inter-scanner analyses (ICCs of 0.976 – 0.999). Intra-scanner reliability for mean cortical thickness measurements was ‘excellent’ for right total cortex, resulting in an ICC of 0.901, but otherwise ‘good’ for left and total cortex, parahippocampus, superior frontal cortex (ICCs of 0.754 – 0.875). Inter-scanner reliability for mean cortical thickness estimates were most variable across the brain structures. Here, results demonstrated ‘excellent’ reliability for the parahippocampus and left total cortex (ICCs of 0.907 – 0.965), ‘good’ for total cortex (ICC of 0.835), ‘moderate’ for right total cortex, right and total superior frontal cortex (ICCs of 0.520 – 0.676), and ‘poor’ for the left superior frontal cortex which produced an ICC of 0.470. Overall, mean cortical thickness estimates of the superior frontal cortex from two different MR scanners showed the least reliability. Discussion Results confirmed highly reliable estimates for gray matter volumes in all brain structures, both from images acquired within the same scanner and across two different scanners. However, the findings indicated increased variability of mean cortical thickness estimates, particularly between scanners, which should be considered when interpreting study findings. Multicentre structural neuroimaging within the field of psychosis is becoming more common and it must be acknowledged that combining MRI data in multicentre studies will contribute additional sources of variance and potential bias with certain brain regions affected more than others.
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Lowe, Gerry, Bruce Spottiswoode, Jerome Declerck, Keith Sullivan, Mhd Saeed Sharif, Wai-Lup Wong e Bal Sanghera. "Positron emission tomography PET/CT harmonisation study of different clinical PET/CT scanners using commercially available software". BJR|Open 2, n. 1 (novembre 2020): 20190035. http://dx.doi.org/10.1259/bjro.20190035.
Testo completoAbstract (sommario):
Objectives: Harmonisation is the process whereby standardised uptake values from different scanners can be made comparable. This PET/CT pilot study aimed to evaluate the effectiveness of harmonisation of a modern scanner with image reconstruction incorporating resolution recovery (RR) with another vendor older scanner operated in two-dimensional (2D) mode, and for both against a European standard (EARL). The vendor-proprietary software EQ•PET was used, which achieves harmonisation with a Gaussian smoothing. A substudy investigated effect of RR on harmonisation. Methods: Phantom studies on each scanner were performed to optimise the smoothing parameters required to achieve successful harmonisation. 80 patients were retrospectively selected; half were imaged on each scanner. As proof of principle, a cohort of 10 patients was selected from the modern scanner subjects to study the effects of RR on harmonisation. Results: Before harmonisation, the modern scanner without RR adhered to EARL specification. Using the phantom data, filters were derived for optimal harmonisation between scanners and with and without RR as applicable, to the EARL standard. The 80-patient cohort did not reveal any statistically significant differences. In the 10-patient cohort SUVmax for RR > no RR irrespective of harmonisation but differences lacked statistical significance (one-way ANOVA F(3.36) = 0.37, p = 0.78). Bland-Altman analysis showed that harmonisation reduced the SUVmax ratio between RR and no RR to 1.07 (95% CI 0.96–1.18) with no outliers. Conclusions: EQ•PET successfully enabled harmonisation between modern and older scanners and against the EARL standard. Harmonisation reduces SUVmax and dependence on the use of RR in the modern scanner. Advances in knowledge: EQ•PET is feasible to harmonise different PET/CT scanners and reduces the effect of RR on SUVmax.
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Zhen, Chen, Eric A. Finkelstein, Shawn A. Karns, Ephraim S. Leibtag e Chenhua Zhang. "Scanner Data‐Based Panel Price Indexes". American Journal of Agricultural Economics 101, n. 1 (18 giugno 2018): 311–29. http://dx.doi.org/10.1093/ajae/aay032.
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Skrzypczyński, Piotr. "Environment Modelling Using Optical Scanner Data". IFAC Proceedings Volumes 30, n. 20 (settembre 1997): 181–86. http://dx.doi.org/10.1016/s1474-6670(17)44262-5.
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Burian, F., L. Zalud, T. Florian e T. Jilek. "Unified Storage for Laser Scanner Data*". IFAC Proceedings Volumes 45, n. 7 (2012): 63–66. http://dx.doi.org/10.3182/20120523-3-cz-3015.00014.
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Ghosh, Amit K. "Targeted promotions using scanner panel data". Journal of Product & Brand Management 6, n. 6 (dicembre 1997): 405–16. http://dx.doi.org/10.1108/10610429710190450.
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Kamakura, Wagner A., e Gary J. Russell. "Measuring brand value with scanner data". International Journal of Research in Marketing 10, n. 1 (marzo 1993): 9–22. http://dx.doi.org/10.1016/0167-8116(93)90030-3.
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Hwang, Seongyoon, e Taehun Jung. "Measuring Price Rigidity Using Scanner Data". Korean Development Economics Association 27, n. 2 (30 giugno 2021): 101–25. http://dx.doi.org/10.20464/kdea.2021.27.2.4.
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Shelburne, Edward. "Producing High-Quality 3-D Models for Specimen Research with the Creaform 3-D Scanner at the Sternberg Museum of Natural History". Biodiversity Information Science and Standards 2 (15 giugno 2018): e25908. http://dx.doi.org/10.3897/biss.2.25908.
Testo completoAbstract (sommario):
Digitization of natural history collections for specimen accessibility, research, and posterity has been a major push in museums over the past decade. One increasingly common form of specimen digitization is three-dimensional (3-D) surface scanning. There are numerous 3-D scanners on the market, including visible light and laser surface scanners. However, mobility of the scanning device, mesh resolution, and texture fidelity are among the most prominent issues facing regular implementation of 3-D scanning procedures for research purposes. Morphometrics research involving the digitization of Xiphactinus at the Sternberg Museum of Natural History (FHSM) using a Creaform Go!SCAN 50 visible light 3-D surface scanner has necessitated the development of a workflow using this 3-D scanner and the associated VXelements software. This workflow maximizes model quality with minimal loss of speed or efficiency when scanning numerous specimens. Major components of this workflow include proper use of positioning targets, appropriate merging of multiple specimen scans, and how to perform post-processing on models without sacrificing model resolution or texture. The primary benefit of the Creaform 3-D scanner is hardware mobility, allowing for use on large exhibited specimens or digitizing specimens during research trips. Shortcomings include relatively low mesh resolution, (bottoming out at 0.5 mm), difficulty scanning highly complex structures, and low texture fidelity of scanned models. However, texture fidelity can be improved through use of the free software, Meshlab, by overlaying high-quality stacked photographs onto the 3-D mesh. Incorporating Meshlab texture overlays into the workflow allows for the production of digital models with improved color and textural data – ideal for accurate visualization of specimens in 3-D viewers for educational outreach and online databases. While not perfect for all applications, the Creaform 3-D scanner allows for rapid digitization of specimens in an increasingly digital collections environment, and is sufficient for some research applications. The workflow established at the FHSM can serve as a framework for other institutions to use the Creaform 3-D scanner to best suit their digitization needs.
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Hoffman, Mark S. "Impact of Scanning Technololgy and Package Design on the Ergonomics of Scanning at the Checkout". Proceedings of the Human Factors and Ergonomics Society Annual Meeting 40, n. 7 (ottobre 1996): 429–33. http://dx.doi.org/10.1177/154193129604000712.
Testo completoAbstract (sommario):
The design of bar code scanners has steadily improved scanning performances over the past twenty years. Changes in scan patterns, improvements in decode algorithms, and design features of the hardware user interface have resulted in scanners that are ergonomically superior both in biomechanics and overall performance. This study reviewed scanner performance and technological developments, and compare these to changes in packaging designs. The results showed that future innovations in scanner design will have minimal impact on improving throughput and the accuracy of data captured because of package design and bar code placement.
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Мирзоева, Мария, Maria Mirzoeva, Сергей Жолудев e Sergey Zholudev. "COMPARATIVE CHARACTERISTICS OF THE FIT CERAMIC RESTORATIONS ― A PILOT STUDY". Actual problems in dentistry 14, n. 3 (23 ottobre 2018): 41–44. http://dx.doi.org/10.18481/2077-7566-2018-14-3-41-44.
Testo completoAbstract (sommario):
Importance. The development of digital dentistry allows the use of new technologies to create orthopedic structures. Scanners in orthopedic dentistry are becoming an integral part of quality prosthetics. To work with new scanners requires not only the ability to perform the scanning procedure itself, but also to understand how accurately the scanner reproduces the surface relief. To determine the contact density of all-ceramic inserts in the removed teeth, this study was carried out.
Objectives. Experimental comparison of the accuracy of the adhesion of all-ceramic inserts made using the VT Dental scanner (Russia).
Methods. The study was conducted at the Department of Orthopedic Dentistry of the State Pedagogical University in the UGMU, in the Urals Branch of the RAS of the Institute of Geology and Geochemistry. acad. A.N. Zavaritsky - in the laboratory of physical and chemical methods of research. Removed molars and premolars of the upper and lower jaws in an amount of 20 pcs. They were processed, prepared under the all-ceramic inserts on the occlusal surfaces. Scanners for registering the relief of cavities: VT Dental (Russia), D500 (3Shape, Denmark), InEos Blue (DentsplySirona, Germany). The device for milling: Wieland dental zenotec select hybrid. The material of the tabs is E.MAX Press (Ivoclar Vivadent, Germany). Cements for fixation: RelyX Ultimate (3M ESPE, USA), Multilink Automix (Ivoclar Vivadent, Germany), MaxCem Elite (Kerr, Italy). The made inserts were fixed in equal parts in the cavities of the removed teeth on the presented cements, longitudinal sections of the remote molars and premolars were created. The method of investigation is scanning electron microscopy. Statistical processing was carried out in Gretl software.
Results. As a result of the scanning electron microscopy of 20 sections in aggregate, data were obtained on the accuracy of the adherence of a ceramic insert made using a VT Dental scanner (Russia) that did not significantly differ from the data obtained with other scanners by 0.4, the scanning accuracy was 95% (CI 1.3-1.9). The results obtained do not exceed the permissible probable error (p≤0,05).
Conclusions. The density of adherence of all-curly inserts in the cavity that were scanned by the VT Dental scanner (Russia) tends to the maximum permissible taking into account the scanning error and in comparison with the world analogues of the scanning device.
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Bonin, Rémi, Farbod Khameneifar e J. R. R. Mayer. "Evaluation of the Metrological Performance of a Handheld 3D Laser Scanner Using a Pseudo-3D Ball-Lattice Artifact". Sensors 21, n. 6 (18 marzo 2021): 2137. http://dx.doi.org/10.3390/s21062137.
Testo completoAbstract (sommario):
This paper proposes the use of a pseudo-3D ball-lattice artifact to characterize a handheld laser scanner from a metrological standpoint. The artifact allows the computation of local and global errors in measurement by using the reference-frame-independent parameters of size, form, and distance within the measuring volume of the scanner, and in a single point cloud, without the need for registration. A set of tests was performed using the whole measuring volume, and three acquisition parameters, namely the orientation of the sweeps during the scans, the exposure time, and the distance to the scanner were analyzed for their effects on the accuracy of the scan data. A composite error including the errors in measuring size, form, and distance was used as a single figure of merit to characterize the performance of the scanner in relation to the data-acquisition parameters. The orientation of sweeps did not have a considerable effect on the errors. The accuracy of the scan data was strongly affected by exposure time and its interaction with the distance at which the artifact was scanned. The errors followed a quadratic trend with respect to the distance of the artifact to the scanner. The tested scanner performed best at its manufacturer’s recommended stand-off distance.
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Paquette, Steven, J. David Brantley, Brian D. Corner, Peng Li e Thomas Oliver. "Automated Extraction of Anthropometric Data from 3D Images". Proceedings of the Human Factors and Ergonomics Society Annual Meeting 44, n. 38 (luglio 2000): 727–30. http://dx.doi.org/10.1177/154193120004403811.
Testo completoAbstract (sommario):
The use of 3D scanning systems for the capture and measurement of human body dimensions is becoming commonplace. While the ability of available scanning systems to record the surface anatomy of the human body is generally regarded as acceptable for most applications, effective use of the images to obtain anthropometric data requires specially developed data extraction software. However, for large data sets, extraction of useful information can be quite time consuming. A major benefit therefore is to possess an automated software program that quickly facilitates the extraction of reliable anthropometric data from 3D scanned images. In this paper the accuracy and variability of two fully automated data extraction systems (Cyberware WB-4 scanner with Natick-Scan software and Hamamatsu BL Scanner with accompanying software) are examined and compared with measurements obtained from traditional anthropometry. In order to remove many confounding variables that living humans introduce during the scanning process, a set of clothing dressforms was chosen as the focus of study. An analysis of the measurement data generally indicates that automated data extraction compares favorably with standard anthropometry for some measurements but requires additional refinement for others.
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R. Shahrin, M., F. H. Hashim, W. M.D.W. Zaki, A. Hussain e T. T. Raj. "3D Indoor Mapping System Using 2D LiDAR Sensor for Drones". International Journal of Engineering & Technology 7, n. 4.11 (2 ottobre 2018): 179. http://dx.doi.org/10.14419/ijet.v7i4.11.20797.
Testo completoAbstract (sommario):
Most 3D scanners are heavy, bulky and costly. These are the major factors that make them irrelevant to be attached to a drone for autonomous navigation. With modern technologies, it is possible to design a simple 3D scanner for autonomous navigation. The objective of this study is to design a cost effective 3D indoor mapping system using a 2D light detection and ranging (LiDAR) sensor for a drone. This simple 3D scanner is realised using a LiDAR sensor together with two servo motors to create the azimuth and elevation axes. An Arduino Uno is used as the interface between the scanner and computer for the real-time communication via serial port. In addition, an open source Point-Cloud Tool software is used to test and view the 3D scanner data. To study the accuracy and efficiency of the system, the LiDAR sensor data from the scanner is obtained in real-time in point-cloud form. The experimental results proved that the proposed system can perform the 2D and 3D scans with tolerable performance.
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Gollob, Christoph, Tim Ritter e Arne Nothdurft. "Comparison of 3D Point Clouds Obtained by Terrestrial Laser Scanning and Personal Laser Scanning on Forest Inventory Sample Plots". Data 5, n. 4 (31 ottobre 2020): 103. http://dx.doi.org/10.3390/data5040103.
Testo completoAbstract (sommario):
In forest inventory, trees are usually measured using handheld instruments; among the most relevant are calipers, inclinometers, ultrasonic devices, and laser range finders. Traditional forest inventory has been redesigned since modern laser scanner technology became available. Laser scanners generate massive data in the form of 3D point clouds. We have developed a novel methodology to provide estimates of the tree positions, stem diameters, and tree heights from these 3D point clouds. This dataset was made publicly accessible to test new software routines for the automatic measurement of forest trees using laser scanner data. Benchmark studies with performance tests of different algorithms are welcome. The dataset contains co-registered raw 3D point-cloud data collected on 20 forest inventory sample plots in Austria. The data were collected by two different laser scanning systems: (1) A mobile personal laser scanner (PLS) (ZEB Horizon, GeoSLAM Ltd., Nottingham, UK) and (2) a static terrestrial laser scanner (TLS) (Focus3D X330, Faro Technologies Inc., Lake Mary, FL, USA). The data also contain digital terrain models (DTMs), field measurements as reference data (ground-truth), and the output of recent software routines for the automatic tree detection and the automatic stem diameter measurement.
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Voges, R., C. S. Wieghardt e B. Wagner. "TIMESTAMP OFFSET DETERMINATION BETWEEN AN ACTUATED LASER SCANNER AND ITS CORRESPONDING MOTOR". ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-1/W1 (30 maggio 2017): 99–106. http://dx.doi.org/10.5194/isprs-annals-iv-1-w1-99-2017.
Testo completoAbstract (sommario):
Motor actuated 2D laser scanners are key sensors for many robotics applications that need wide ranging but low cost 3D data. There exist many approaches on how to build a 3D laser scanner using this technique, but they often lack proper synchronization for the timestamps of the actuator and the laser scanner. However, to transform the measurement points into three-dimensional space an appropriate synchronization is mandatory. Thus, we propose two different approaches to accomplish the goal of calculating timestamp offsets between laser scanner and motor prior to and after data acquisition. Both approaches use parts of a SLAM algorithm but apply different criteria to find an appropriate solution. While the approach for offset calculation prior to data acquisition exploits the fact that the SLAM algorithm should not register motion for a stationary system, the approach for offset calculation after data acquisition evaluates the perceived clarity of a point cloud created by the SLAM algorithm. Our experiments show that both approaches yield the same results although operating independently on different data, which demonstrates that the results reflect reality with a high probability. Furthermore, our experiments exhibit the significance of a proper synchronization between laser scanner and actuator.
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Blaskow, R., e D. Schneider. "Analysis and correction of the dependency between laser scanner intensity values and range". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-5 (5 giugno 2014): 107–12. http://dx.doi.org/10.5194/isprsarchives-xl-5-107-2014.
Testo completoAbstract (sommario):
Intensity values, which are registered by a terrestrial laser scanner system (TLS) for each point of a 3D point cloud in addition to its coordinates, are affected by the characteristic of the measured object and the parameters of the environment. The backscattered electromagnetic signal is influenced in his strength by the reflectivity of the scanned object surface, the incidence angle, the distance between laser scanner and object and the atmospheric respectively system specific setting of the TLS-measurement. The entity of all influences on the signal can be summarized in the laser range equation of <i>Jelalian</i><sup>1</sup>. For the investigations of this study the named influences where divided into two groups. Group 1 includes the surface specific influences. The second group contains all other influences. The correction of the intensity values from the effects of group 2 theoretically allows the determination of similar materials, using similar intensity values in laser scanner point clouds. In this paper the dependency between laser scanner intensity values and range are investigated on the basis of laser scanner data recorded with a Riegl LMS-Z420i. The results are compared with data from the phase-difference laser scanner Zoller+Fröhlich Imager 5006i.
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Russell, Gary J., e Wagner A. Kamakura. "Understanding Brand Competition Using Micro and Macro Scanner Data". Journal of Marketing Research 31, n. 2 (maggio 1994): 289–303. http://dx.doi.org/10.1177/002224379403100211.
Testo completoAbstract (sommario):
Recent advances in data gathering through checkout scanners have produced vast amounts of data on the actual behavior of consumers in the marketplace, creating new opportunities for managers and researchers to understand competition and consumers’ response to the marketing mix. Previous analyses of this data in the literature have focused either at the household (micro) or store (macro) level. The authors propose a method of enriching the analysis of competitive behavior by combining the in-depth consumer information obtained from a micro-level household scanner panel with the comprehensive market data supplied by a macro-level retail-tracking panel. The approach offers the manager detailed information about consumers (e.g., identification of consumer segments in terms of brand preferences and socioeconomic characteristics) along with strategic diagnostics of the product-market (e.g., the sensitivity of the market to price promotions, impact of a brand's strategy on competitors, vulnerability of the brand to competitive actions).
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Danielis, Alessandro, Massimiliano Guarneri, Massimo Francucci, Mario Ferri De Collibus, Giorgio Fornetti e Arianna Mencattini. "A Quadratic Model with Nonpolynomial Terms for Remote Colorimetric Calibration of 3D Laser Scanner Data Based on Piecewise Cubic Hermite Polynomials". Mathematical Problems in Engineering 2015 (2015): 1–14. http://dx.doi.org/10.1155/2015/606948.
Testo completoAbstract (sommario):
The processing of intensity data from terrestrial laser scanners has attracted considerable attention in recent years. Accurate calibrated intensity could give added value for laser scanning campaigns, for example, in producing faithful 3D colour models of real targets and classifying easier and more reliable automatic tools. In cultural heritage area, the purely geometric information provided by the vast majority of currently available scanners is not enough for most applications, where indeed accurate colorimetric data is needed. This paper presents a remote calibration method for self-registered RGB colour data provided by a 3D tristimulus laser scanner prototype. Such distinguishing colour information opens new scenarios and problems for remote colorimetry. Using piecewise cubic Hermite polynomials, a quadratic model with nonpolynomial terms for reducing inaccuracies occurring in remote colour measurement is implemented. Colorimetric data recorded by the prototype on certified diffusive targets is processed for generating a remote Lambertian model used for assessing the accuracy of the proposed algorithm. Results concerning laser scanner digitizations of artworks are reported to confirm the effectiveness of the method.