Articles de revues : « LE. Scanners »

1

Rotar, Raul Nicolae, Anca Jivanescu, Codruta Ille, Angela Codruta Podariu, Daniela Elisabeta Jumanca, Ana-Maria Matichescu, Octavia Balean et Laura Cristina Rusu. « Trueness and Precision of Two Intraoral Scanners : A Comparative In Vitro Study ». Scanning 2019 (21 octobre 2019) : 1–6. http://dx.doi.org/10.1155/2019/1289570.

Texte intégral

Résumé :

The aim of this study was to evaluate the accuracy of two intraoral scanners used in the dental office. A molar fixed in a typodont was prepared for a ceramic onlay. The preparation was scanned using a high-resolution scanner (reference scanner) and saved as stereolithography (STL) format. The prepared resin molar was scanned again using the intraoral scanners, and all the scans were saved as well in STL format. All STL files were compared using metrology software (Geomagic Control X). Overlapping the meshes allowed the assessment of the scans in terms of trueness and precision. Based on the results of this study, the differences of trueness and precision between the intraoral scanners were minimal.

Styles APA, Harvard, Vancouver, ISO, etc.

2

Carvalho, William S., Viviane de S. M. Almeida, Leonardo Provedel, Anderson da S. Maciel et Viviane A. Sarmento. « Volumetric Evaluation of 3D Models Generated by Different Surface Treatment Protocols ». European Journal of Dental and Oral Health 3, n^o 5 (23 décembre 2022) : 5–8. http://dx.doi.org/10.24018/ejdent.2022.3.5.229.

Texte intégral

Résumé :

The objective of this study was to compare the volume of three-dimensional (3D) models generated by different scanners and computational modeling protocols. Eight dry mandibles were scanned by five different computed tomography (CT) scanners and by a 3D-scanner. Three-dimensional models were generated, received different surface treatment processes, and the final volume of the 3D models was compared. The results show that there was no significant difference among the volume of the 3D models generated by the different CT scanners and surface treatment techniques, however, the model volume generated by the 3D-scanner show the highest volume. It can be concluded that the different combinations of surface treatment protocols did not determine differences in the model volume generated by different CT and CBCT scanners and that the 3D-scanner determined the highest volume models.

Styles APA, Harvard, Vancouver, ISO, etc.

3

Rabah, Chaima Ben, Gouenou Coatrieux et Riadh Abdelfattah. « Boosting up Source Scanner Identification Using Wavelets and Convolutional Neural Networks ». Traitement du Signal 37, n^o 6 (31 décembre 2020) : 881–88. http://dx.doi.org/10.18280/ts.370601.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

4

Baier, Valentin, Michael Schardt, Maximilian Fink, Martin Jakobi et Alexander W. Koch. « MEMS-Scanner Testbench for High Field of View LiDAR Applications ». Sensors 22, n^o 1 (22 décembre 2021) : 39. http://dx.doi.org/10.3390/s22010039.

Texte intégral

Résumé :

LiDAR sensors are a key technology for enabling safe autonomous cars. For highway applications, such systems must have a long range, and the covered field of view (FoV) of >45° must be scanned with resolutions higher than 0.1°. These specifications can be met by modern MEMS scanners, which are chosen for their robustness and scalability. For the automotive market, these sensors, and especially the scanners within, must be tested to the highest standards. We propose a novel measurement setup for characterizing and validating these kinds of scanners based on a position-sensitive detector (PSD) by imaging a deflected laser beam from a diffuser screen onto the PSD. A so-called ray trace shifting technique (RTST) was used to minimize manual calibration effort, to reduce external mounting errors, and to enable dynamical one-shot measurements of the scanner’s steering angle over large FoVs. This paper describes the overall setup and the calibration method according to a standard camera calibration. We further show the setup’s capabilities by validating it with a statically set rotating stage and a dynamically oscillating MEMS scanner. The setup was found to be capable of measuring LiDAR MEMS scanners with a maximum FoV of 47° dynamically, with an uncertainty of less than 1%.

Styles APA, Harvard, Vancouver, ISO, etc.

5

Cai, HongXin, Bing Cheng Zhao, Yueyi Tian, Dong-Hyuck Kim, Yunhan Sun, Ho-Kyung Lim, Eui-Seok Lee et Heng Bo Jiang. « Design of a Single-Tooth Model and Its Application in Oral Scan System Assessment ». Scanning 2021 (21 mars 2021) : 1–8. http://dx.doi.org/10.1155/2021/8891396.

Texte intégral

Résumé :

Intraoral scanners have been widely used in the application of dentistry. Accuracy includes trueness and precision; they have an important position in the assessment of intraoral scanners. The existing standard models are divided into the inlay and the crown, but the operation is relatively complicated. In this study, in order to simplify the current standard model, we designed a new integration model to compare the accuracy of two intraoral scanners (CEREC and TRIOS) and an extraoral scanner (SHINING). The coordinate measuring machine measured value is the gold standard. Values of the length and angle were analyzed by converting the scanned digital impressions into an STL (standard triangulation language) format to evaluate the accuracy of the intraoral scanner and to verify the feasibility of the designed model. The result shows that the integration model can be successfully scanned and imaged. In the case of the powder-free integration model, intraoral scanner precision, trueness, 3D fitting, and imaging are better than the extraoral scanner. It can be seen straightly from the measurement result and the 3D fitting result that the intraoral scanner can acquire the shape of the standard model integrally with good repeatability. Therefore, it can be concluded that TRIOS is superior to CEREC and SHINING in accuracy, and the integration model is feasible as a reference in the examination of intraoral scanners. The performance of the newly designed integration model that can be scanned is clinically significant, suggesting that this model can be used as a standard reference model.

Styles APA, Harvard, Vancouver, ISO, etc.

6

Bohner, Lauren, Daniel Habor, Klaus Radermacher, Stefan Wolfart et Juliana Marotti. « Scanning of a Dental Implant with a High-Frequency Ultrasound Scanner : A Pilot Study ». Applied Sciences 11, n^o 12 (14 juin 2021) : 5494. http://dx.doi.org/10.3390/app11125494.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Xue, Song, Rui Guo, Karl Peter Bohn, Jared Matzke, Marco Viscione, Ian Alberts, Hongping Meng et al. « A cross-scanner and cross-tracer deep learning method for the recovery of standard-dose imaging quality from low-dose PET ». European Journal of Nuclear Medicine and Molecular Imaging 49, n^o 6 (24 décembre 2021) : 1843–56. http://dx.doi.org/10.1007/s00259-021-05644-1.

Texte intégral

Résumé :

Abstract Purpose A critical bottleneck for the credibility of artificial intelligence (AI) is replicating the results in the diversity of clinical practice. We aimed to develop an AI that can be independently applied to recover high-quality imaging from low-dose scans on different scanners and tracers. Methods Brain [18F]FDG PET imaging of 237 patients scanned with one scanner was used for the development of AI technology. The developed algorithm was then tested on [18F]FDG PET images of 45 patients scanned with three different scanners, [18F]FET PET images of 18 patients scanned with two different scanners, as well as [18F]Florbetapir images of 10 patients. A conditional generative adversarial network (GAN) was customized for cross-scanner and cross-tracer optimization. Three nuclear medicine physicians independently assessed the utility of the results in a clinical setting. Results The improvement achieved by AI recovery significantly correlated with the baseline image quality indicated by structural similarity index measurement (SSIM) (r = −0.71, p < 0.05) and normalized dose acquisition (r = −0.60, p < 0.05). Our cross-scanner and cross-tracer AI methodology showed utility based on both physical and clinical image assessment (p < 0.05). Conclusion The deep learning development for extensible application on unknown scanners and tracers may improve the trustworthiness and clinical acceptability of AI-based dose reduction.

Styles APA, Harvard, Vancouver, ISO, etc.

8

Burde, Alexandru Victor, Marius Manole, Radu-Septimiu Campian, Cosmin Sinescu et Sorana Baciu. « In vitro Comparison of Accuracy of Two Scanners Used in Dental Medicine ». Revista de Chimie 70, n^o 7 (15 août 2019) : 2344–46. http://dx.doi.org/10.37358/rc.19.7.7336.

Texte intégral

Résumé :

This experimental study aims to highlight and compare the resolution and accuracy (trueness and fidelity) of an intraoral scanner and a laboratory scanner. In order to achieve the aim of this study, an experimental model consisting of a die with a standard preparation for a porcelain-fused to metal crown was manufactured from a physiognomic polymethylmethacrylate resin. The experimental model was scanned with an industrial CT to obtain the virtual reference model. Then, the die was scanned 15 times with each scanner. In order to asses trueness, comparisons were made with the virtual reference model, and for fidelity, the first scan in the series was compared with the following scans. In regards to the trueness of the scanners, the average deviation for the laboratory scanner is 4.31 and 17.34 mm for the intraoral scanner. When comparing the serial scannings� of the same die, the lowest recorded deviation is 6.4 mm for the laboratory scanner and 21.57mm for the intraoral scanner. For both fidelity and trueness, the F test demonstrates that there is a statistically significant difference between the scanners and the applied T-tests confirm the lower degree of error-rate generation by the laboratory scanner. The dimensional limitations imposed for the intraoral scanners have a direct consequence on their trueness and fidelity when compared to their laboratory counterparts.

Styles APA, Harvard, Vancouver, ISO, etc.

9

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^o 03 (2012) : 101–10. http://dx.doi.org/10.3413/nukmed-0452-11-12.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

10

Jafri, Syed Riaz un Nabi, Sheraz Shamim, Sadia Muniza Faraz, Asif Ahmed, Syed Muhammad Yasir et Jamshed Iqbal. « Characterization and calibration of multiple 2D laser scanners ». PLOS ONE 17, n^o 7 (28 juillet 2022) : e0272063. http://dx.doi.org/10.1371/journal.pone.0272063.

Texte intégral

Résumé :

This paper presents the comparative evaluation of multiple compact and lightweight 2D laser scanners for their possible backpack based scanning and mapping applications. These scanners include Hokuyo URG-04LX, Slamtec RPLidar A1-M8 and Hokuyo UTM-30LX-EW scanners. Since the technical datasheets provide general information and limited working details, this research presents a thorough study on the performance of each scanner related explicitly to indoor mapping operations. A series of scanning experiments have been performed for the characterization of each scanner using statistical analysis. During the testing, all the scanning data has been recorded using Robot Operating System (ROS) and then computed in offline processing. In initial tests, each scanner’s drift effect on range measurements has been tested and presented in the relevant section of the paper. In continuation, the effect of various scanning distances on measurement accuracy has been evaluated and discussed. Later the impact of various materials typically found in indoor vicinities and their respective properties of color and smoothness have been tested and provided in the paper. Finally, a Kalman Filtering based mathematical formulation has been utilized to calibrate each scanner and to reduce the measuring uncertainties as observed in various tests for each scanner.

Styles APA, Harvard, Vancouver, ISO, etc.

11

Lee, Dong-Geun, Keunbada Son et Kyu-Bok Lee. « Comparison of the Accuracy of Intraoral Scanners Based on the Type of Tooth Preparation for a Single Crown ». Applied Sciences 11, n^o 20 (10 octobre 2021) : 9399. http://dx.doi.org/10.3390/app11209399.

Texte intégral

Résumé :

The purpose of this study was to evaluate the accuracy of intraoral scanners in 10 abutments (five premolars and five molars) obtained in a dental clinic and to analyze the impacts of the volume and area of abutments on scanning accuracy. Abutment casts were scanned five times with a 3D contact scanner (DS10; Renishaw plc). The five scan files were lined up and then merged, and one high-resolution computer-aided design reference model (CRM) was obtained. To obtain a computer-aided design test model (CTM), three types of intraoral scanners (CS3600 (Carestream Dental), i500 (Medit), and EZIS PO (DDS)) and one type of laboratory scanner (E1; 3Shape) were employed. Using 3D analysis software (Geomagic control X; 3D Systems), the accuracy of the scanners was evaluated, including optimal overlap by optimal alignment. The conformity of the overlapped data was calculated by the root mean square (RMS) value, using the 3D compare function for evaluation. As for statistical analysis, testing was conducted, using one-way and two-way ANOVA and the Tukey HSD test (α = 0.05) for the comparison of the groups. To analyze the correlations of the volume and area of the abutments with accuracy, Pearson’s correlation analysis was conducted (α = 0.00625). Both premolar and molar abutments showed a lower RMS value on the laboratory scanner than on the intraoral scanners, and the RMS value was lower in premolars than in molars (p < 0.001). In the intraoral scanner group, CS3600 showed the best accuracy (p < 0.001). There were significant positive correlations for the volume and area of the abutments with accuracy (p < 0.001). The type, volume, and area of the clinically applicable abutments may affect the accuracy of intraoral scanners; however, the scanners used in the present study showed a clinically acceptable accuracy range, regardless of the type of abutment.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Choi, Kyu Sung, Whal Lee, Joon Hyung Jung et Eun-Ah Park. « Reproducibility of calcium scoring of the coronary arteries : comparison between different vendors and iterative reconstructions ». Acta Radiologica Open 9, n^o 4 (avril 2020) : 205846012092214. http://dx.doi.org/10.1177/2058460120922147.

Texte intégral

Résumé :

Background The coronary artery calcium scoring (CCS) has been widely used for cardiac risk stratification for asymptomatic patients. Purpose To assess the reproducibility of CCS performed on four different computed tomography (CT) scanners, and compare the variability between two reconstruction algorithms, filtered back projection (FBP), and iterative reconstruction (IR). Material and Methods A CCS phantom was made from agar and contained 23 pieces of chicken bones. The phantom was repeatedly scanned using four different CT scanners: Toshiba; GE; Philips; and Siemens. Images were reconstructed using FBP and IR. Agatston and volume scores of total bone fragments were calculated and the overall differences between the instruments were evaluated using the Friedman test. Comparison of the Agatston and volume scores between the two reconstruction algorithms, for each instrument, was evaluated using the Wilcoxon signed rank test. Results The difference in the Agatston scores was significantly different between the four machines ( P = 0.001). The Toshiba scanner yielded the highest score followed by Philips, GE, and Siemens scanners. There was no difference in the CCS evaluated using the two reconstruction algorithms, except in case of the Siemens scanner ( P = 0.032). Conclusion CCS performed on different scanners varied significantly. In the Toshiba, Philips, and GE scanners, there was no significant difference in the CCS determined using either an IR or the FBP algorithm. In the Siemens scanner, applying the IR algorithm resulted in a slightly different scores, which might not be clinically significant.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Lee, Sang J., Soo-Woo Kim, Joshua J. Lee et Chan W. Cheong. « Comparison of Intraoral and Extraoral Digital Scanners : Evaluation of Surface Topography and Precision ». Dentistry Journal 8, n^o 2 (20 mai 2020) : 52. http://dx.doi.org/10.3390/dj8020052.

Texte intégral

Résumé :

The aim of this study was to evaluate the surface topography and the precision measurements of different intraoral and extraoral digital scanners. A reference model of a maxillary arch with four implant analogs was prepared and scanned by three intraoral and two extraoral scanners. The reference model was scanned fifteen times with each digital scanning system, investigating the surface topography and precision measurements for the same-arch and cross-arch measurements. The data was exported to 3D inspection and mesh-processing software (GOM Inspect, Braunschweig, Germany). Statistical analysis was performed using a one-way Analysis of Variance (ANOVA) with the Tukey method for pairwise comparisons. The effect of parameters on generating the surface topography was analyzed by Univariate Linear Regression Analysis. Of the scanner systems evaluated, iTero (IT) exhibited the most number of triangulation points, followed by Trios 3 Shape (TR) and Straumann Cares (SC). There were no significant differences observed in the surface topography when comparing flat and contoured surfaces, the anterior and posterior position, and interproximal areas. For the precision measurement in the same quadrant, no statistical difference was noted between intra- and extraoral scanners. However, the extraoral scanners showed substantially higher precision measurements for the cross-arch measurement. Surface topography did not correlate to precision. Rather, precision correlated with the scanning mechanism. For a quadrant scanning, both intraoral and extraoral scanners are recommended, but extraoral scanners are recommended for a full-arch scanning.

Styles APA, Harvard, Vancouver, ISO, etc.

14

Song, Jihu, et Minji Kim. « Accuracy on Scanned Images of Full Arch Models with Orthodontic Brackets by Various Intraoral Scanners in the Presence of Artificial Saliva ». BioMed Research International 2020 (27 février 2020) : 1–8. http://dx.doi.org/10.1155/2020/2920804.

Texte intégral

Résumé :

Aim. This study aims to evaluate the accuracy of scanned images of 4 clinically used intraoral scanners (CS3600, i500, Trios3, Omnicam) when scanning the surface of full arch models with various kinds of orthodontic brackets in the presence of artificial saliva. Materials and Methods. Four study models were prepared; bonded with ceramic, metal, and resin brackets, respectively, and without brackets. Reference images were taken by scanning the models with an industrial scanner. Study models were then applied with an artificial saliva and scanned 10 times, respectively, with the above 4 intraoral scanners. All images were converted to STL file format and analyzed with 3D analysis software. By superimposing with the reference images, mean maximum discrepancy values and mean discrepancy values were collected and compared. For statistical analysis, two-way ANOVA was used. Results. Omnicam (1.247 ± 0.255) showed higher mean maximum discrepancy values. CS3600 (0.758 ± 0.170), Trios3 (0.854 ± 0.166), and i500 (0.975 ± 0.172) performed relatively favourably. Resin (1.119 ± 0.255) and metal (1.086 ± 0.132) brackets showed higher mean maximum discrepancy values. Nonbracket (0.776 ± 0.250) and ceramic bracket (0.853 ± 0.269) models generally showed lower mean maximum discrepancy values in studied scanners. In mean discrepancy values, the difference between scanners was not statistically significant whereas among brackets, resin bracketed models (0.093 ± 0.142) showed the highest value. Conclusion. Intraoral scanners and brackets had significant influences on the scanned images with application of artificial saliva on the study models. It may be expected to have similar outcomes in an intraoral environment. Some data showed the discrepancy values up to about 1.5 mm that would require more caution in using intraoral scanners for production of detailed appliances and records.

Styles APA, Harvard, Vancouver, ISO, etc.

15

Lee, Kyungmin Clara, et Seong-Joon Park. « Digital Intraoral Scanners and Alginate Impressions in Reproducing Full Dental Arches : A Comparative 3D Assessment ». Applied Sciences 10, n^o 21 (29 octobre 2020) : 7637. http://dx.doi.org/10.3390/app10217637.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

16

Bucuresteanu, Anca, Dan Prodan et Adrian Motomancea. « Execution of Plastic Parts Using 3D Scanners and 3D Printers ». Materiale Plastice 55, n^o 2 (30 juin 2018) : 215–18. http://dx.doi.org/10.37358/mp.18.2.4998.

Texte intégral

Résumé :

In this paper, the authors show a part of research works performed on the use of 3D scanners and 3D printers to execute plastic parts with complex surfaces. 3D scanning allows copying of certain surfaces in our environment, based on existing models. Scanned models may represent various objects, made of a wide range of materials: metals, ceramics, fabrics, plastics, leather, organic materials etc. [1]. This paper shows the results achieved using a scanner and a common and affordable - low-price - printer. 3D scanners and printers allow execution of clones of certain parts with irregular surfaces.

Styles APA, Harvard, Vancouver, ISO, etc.

17

Spagopoulos, Dimitrios, George Kaisarlis, Foteini Spagopoulou, Demetrios J. Halazonetis, Jan-Frederik Güth et Efstratios Papazoglou. « In Vitro Trueness and Precision of Intraoral Scanners in a Four-Implant Complete-Arch Model ». Dentistry Journal 11, n^o 1 (12 janvier 2023) : 27. http://dx.doi.org/10.3390/dj11010027.

Texte intégral

Résumé :

(1) Background: New intraoral (IOS) and laboratory scanners appear in the market and their trueness and precision have not been compared. (2) Methods: Seven IOS and two laboratory scanners were used to scan a mandibular edentulous model with four parallel internal hexagon implant analogues and PEEK scan bodies. Digital models in Standard Tessellation Language (STL) were created. The master model with the scan bodies was scanned (×10) with a computerized numerical control 3D Coordinate Measuring Machine (CMM). The short (distances of adjacent scan posts) and long distances (distances of the scan posts with non-adjacent sites in the arch) among the centroids of the four analogues were calculated using CMM special software. Trueness (comparisons with the master model) and precision (intragroup comparisons) were statistically compared with ANOVA, chi-square and Tukey tests. (3) Results: Laboratory scanners had the best trueness and precision compared to all IOSs for long distances. Only iTero (Align Technologies Inc., Milpitas, CA, USA) had comparable trueness with one laboratory scanner in short and long distances. For short distances, CS3600 (Carestream Health, Inc., Rochester, NY, USA), Omnicam, Primescan (Sirona Dental Sys-tems GmbH, Bens-heim, Germany) and TRIOS 4 (3Shape A/S, Copen-hagen, Denmark) had similar trueness to one laboratory scanner. From those, only Omnicam and Primescan had similar precision as the same laboratory scanner. Most IOSs seem to work better for smaller distances and are less precise in cross-arch distances. (4) Conclusions: The laboratory scanners showed significantly higher trueness and precision than all IOSs tested for the long-distance group; for the short distance, some IOSs were not different in trueness and precision than the laboratory scanners.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Favero, Riccardo, Andrea Volpato, Maurizio De Francesco, Adolfo Di Fiore, Riccardo Guazzo et Lorenzo Favero. « Accuracy of 3D digital modeling of dental arches ». Dental Press Journal of Orthodontics 24, n^o 1 (février 2019) : 038e1–037e7. http://dx.doi.org/10.1590/2177-6709.24.1.38.e1-7.onl.

Texte intégral

Résumé :

ABSTRACT Objective: The aim of the study was to verify and compare the accuracy of full-arch digital impressions obtained using two intraoral scanners and three scanning methodologies. Methods: A resin model created with dental 3-D printing was scanned by a reference scanner (Zfx Evolution - Zimmer Biomet, Palm Beach Gardens, FL) in order to obtain a 3D reference; the same resin model was then scanned with two different intraoral scanners (Zfx IntraScan and Carestream 3600 - CS 3600®, Carestream, Rochester, NY, USA) using: Technique A (from tooth #27 up to tooth #17); Technique B (from tooth #11 up to tooth #17 and then from tooth #21 up to tooth #27) and Technique C (from tooth #22 up to tooth #17, and then from tooth #12 up to tooth #27 - the MeshLab software v. 1.3.3 was then used to match the two scans). The scans obtained were superimposed over the reference scan by means of a software, and the volumetric discrepancies were calculated. Results: The mean results for the Zfx Intrascan scanner were: Technique A = 302.47 ± 37.42 µm; Technique B = 180.45 ± 29.86 µm; Technique C = 147.34 ± 28.23 µm. The mean results for the Carestream 3600 scanner were: Technique A = 303.59 ± 40.20 µm; Technique B = 181.53 ± 29.61 µm; Technique C = 142.28 ± 35.33 µm. Technique C, used by both scanners, produced less volumetric discrepancies compared to the other techniques. Conclusions: The scanning technique had a statistically significant effect on the quality of the scan (p< 0.0001), whereas the scanner did not present any significant influence (p= 0.91).

Styles APA, Harvard, Vancouver, ISO, etc.

19

Majstorović, Nemanja, Luka Čerče, Davorin Kramar, Mirko Soković, Branislav Glišić, Vidosav Majstorović et Srđan Živković. « Examination of Scanner Precision by Analysing Orthodontic Parameters ». Balkan Journal of Dental Medicine 21, n^o 1 (1 mars 2017) : 32–43. http://dx.doi.org/10.1515/bjdm-2017-0005.

Texte intégral

Résumé :

Summary Background: 3D modelling in orthodontics is becoming an increasingly widespread technique in practice. One of the significant questions already being asked is related to determining the precision of the scanner used for generating surfaces on a 3D model of the jaw. Materials and methods: This research was conducted by generating a set of identical 3D models on Atos optical 3D scanner and Lazak Scan laboratory scanner, which precision was established by measuring a set of orthodontic parameters (54 overall) in all three orthodontic planes. In this manner we explored their precision in space, since they are used for generating spatial models – 3D jaws. Results: There were significant differences between parameters scanned with Atos and Lazak Scan. The smallest difference was 0.017 mm, and the biggest 1.109 mm. Conclusion: This research reveals that both scanners (Atos and Lazak Scan), which belong to general purpose scanners, based on precision parameters can be used in orthodontics. Early analyses indicate that the reference scanner in terms of precision is Atos.

Styles APA, Harvard, Vancouver, ISO, etc.

20

Taguchi, Narumi, Seitaro Oda, Takeshi Nakaura, Daisuke Utsunomiya, Yoshinori Funama, Masanori Imuta, Hideaki Yuki et al. « Contrast enhancement in abdominal computed tomography : influence of photon energy of different scanners ». British Journal of Radiology 91, n^o 1081 (janvier 2018) : 20170285. http://dx.doi.org/10.1259/bjr.20170285.

Texte intégral

Résumé :

Objective: Different CT scanners have different X-ray spectra and photon energies indicating that contrast enhancement vary among scanners. However, this issue has not been fully validated; therefore, we performed phantom and clinical studies to assess this difference. Methods: Two scanners were used: scanner-A and scanner-B. In the phantom study, we compared the contrast enhancement between the scanners at tube voltage peaks of 80, 100 and 120 kVp. Then, we calculated the effective energies of the two CT scanners. In the clinical study, 40 patients underwent abdominal scanning with scanner-A and another 40 patients with scanner-B, with each group using the same scanning protocol. The contrast enhancement of abdominal organs was assessed quantitatively (based on the absolute difference between the attenuation of unenhanced scans and contrast-enhanced scans) and qualitatively. A two-tailed independent Student's t-test and or the Mann–Whitney U test were used to compare the discrepancies. Results: In the phantom study, contrast enhancement for scanner-B was 36.9, 32.6 and 30.8% higher than that for scanner-A at 80, 100 and 120 kVp, respectively. The effective energies were higher for scanner-A than for scanner-B. In the quantitative analysis for the clinical study, scanner-B yielded significantly better contrast enhancement of the hepatic parenchyma, pancreas, kidney, portal vein and inferior vena cava compared with that of scanner-A. The mean visual scores for contrast enhancement were also significantly higher on images obtained by scanner-B than those by scanner-A. Conclusion: There were significant differences in contrast enhancement of the abdominal organs between the compared CT scanners from two different vendors even at the same scanning and contrast parameters. Advances in knowledge: Awareness of the impact of different X-ray energies on the resultant attenuation of contrast material is important when interpreting clinical CT images.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Vyskub, V. G. « POSSIBILITIES AND LIMITATIONS OF COMBINED SCANNERS ». Issues of radio electronics, n^o 5 (20 mai 2018) : 74–82. http://dx.doi.org/10.21778/2218-5453-2018-5-74-82.

Texte intégral

Résumé :

The technique of optical scanning is continuously developing in the direction of creating new and improving existing types of scanners (deflectors), radiation sources, methods of reading, converting and reproducing information. However, the absence of universal scanner, able to satisfy different applications leads to necessity of application of combined scanning, finding the most effective combination of deflectors with complementary characteristics taking into account their limit values. The purpose of this work is an overview of a typical combined of the scanners used in the systems of wide application, analysis of existing experience in the use of combined deflectors. The article discusses the optical schemes of modern combined scanners, which include scanners of different operating principles and design. The analysis of combined devices for various applications is given, which included optical-mechanical, electronic, acoustic-optical, electro-optical scanners, as well as micro-electromechanical (MEMS) systems, expanding the sphere of scanning tools. The consideration was conducted with a wide set of parameters and characteristics, such as speed, resolution, accuracy of the control of the optical beam, the size of the scanned space, etc. Identified features and benefits of the combined scanning for dynamic, precision, spectral, and structural characteristics and functionality, and also are noted difficulty in implementing a combined scanning. Among them are optical harmonization, dynamic, algorithmic and precision matching of scanners integrated into the device.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Brambilla, M., R. Matheoud, C. Basile, C. Bracco, I. Castiglioni, C. Cavedon, M. Cremonesi et al. « An Adaptive Thresholding Method for BTV Estimation Incorporating PET Reconstruction Parameters : A Multicenter Study of the Robustness and the Reliability ». Computational and Mathematical Methods in Medicine 2015 (2015) : 1–12. http://dx.doi.org/10.1155/2015/571473.

Texte intégral

Résumé :

Objective. The aim of this work was to assess robustness and reliability of an adaptive thresholding algorithm for the biological target volume estimation incorporating reconstruction parameters.Method. In a multicenter study, a phantom with spheres of different diameters (6.5–57.4 mm) was filled with18F-FDG at different target-to-background ratios (TBR: 2.5–70) and scanned for different acquisition periods (2–5 min). Image reconstruction algorithms were used varying number of iterations and postreconstruction transaxial smoothing. Optimal thresholds (TS) for volume estimation were determined as percentage of the maximum intensity in the cross section area of the spheres. Multiple regression techniques were used to identify relevant predictors of TS.Results. The goodness of the model fit was high (R2: 0.74–0.92). TBR was the most significant predictor of TS. For all scanners, except the Gemini scanners, FWHM was an independent predictor of TS. Significant differences were observed between scanners of different models, but not between different scanners of the same model. The shrinkage on cross validation was small and indicative of excellent reliability of model estimation.Conclusions. Incorporation of postreconstruction filtering FWHM in an adaptive thresholding algorithm for the BTV estimation allows obtaining a robust and reliable method to be applied to a variety of different scanners, without scanner-specific individual calibration.

Styles APA, Harvard, Vancouver, ISO, etc.

23

Lee, Joo-Hee, Soo-Hwan Byun, Sang-Min Yi, In-Young Park, Byoung-Eun Yang et Hye-Lim Lee. « Efficacy of Constructing Digital Hybrid Skull-Dentition Images Using an Intraoral Scanner and Cone-Beam Computed Tomography ». Scanning 2022 (3 mars 2022) : 1–9. http://dx.doi.org/10.1155/2022/8221514.

Texte intégral

Résumé :

Cone-beam computed tomography (CBCT) can distort dentition, and additional imaging is often required. A plaster model to help digitize dental images has been widely used in clinical practice, but there are some inconveniences such as complexity of the process and the risk of damage. The aim of this study was to evaluate the potential for improving dentition imaging with CBCT scans using an intraoral scanner instead of a plaster model. The study used laser model-scanned images of plaster models, imaging from two intraoral scanners, and CBCT images from 20 patients aged 12-18 years. CS 3600 (Carestream Dental, Atlanta, USA) and i700 (Medit, Seoul, Korea) were used as intraoral scanners. The full arch was scanned at once or in three sections using intraoral scanners. The segmented scans were merged to obtain full-arch images. With i700, full-arch images were additionally acquired using its “smart stich” function. The virtual skull-dentition hybrid images obtained from intraoral scanners were superimposed with images obtained using a plaster cast. The difference and distance of coordinate values at each reference point were measured. The average distances from the images obtained with the plaster cast were smaller than 0.39 mm, which is the voxel size of CBCT. Scanning the complete or partial arch using CS 3600 or i700 satisfactorily complemented the CBCT when compared to the plaster model. The virtual skull-dentition hybrid image obtained from intraoral scanners will be clinically useful, especially for patients and surgeons who have difficulty in scanning the complete arch at once.

Styles APA, Harvard, Vancouver, ISO, etc.

24

Burde, Alexandru Victor, Cristina Gasparik, Marioara Moldovan, Sorana Baciu et Cosmin Cosma. « In vitro Evaluation of Accuracy of Single Dies Captured by Two Intraoral Digital Scanners ». Materiale Plastice 55, n^o 2 (30 juin 2018) : 176–78. http://dx.doi.org/10.37358/mp.18.2.4988.

Texte intégral

Résumé :

The objective of this in-vitro study was to compare the accuracy, defined as trueness and precision, of two intraoral digital scanners that use different capturing techniques. An experimental reference object consisting of a die was manufactured from a PMMA resin. The reference object was digitized with an industrial CT and was scanned 15 times with each scanner. In order to asses trueness, comparisons were made with the virtual reference model, and for fidelity, the first scan in the series was compared with the following scans. For both fidelity and trueness, the F test and T tests demonstrate that there is a statistically significant difference between the scanners.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Lee, Joohee, ByoungEun Yang et Hyelim Lee. « Intraoral Scan for Virtual Skull-Dentition Hybrid Images of Young Patients ». JOURNAL OF THE KOREAN ACADEMY OF PEDTATRIC DENTISTRY 49, n^o 1 (28 février 2022) : 57–64. http://dx.doi.org/10.5933/jkapd.2022.49.1.57.

Texte intégral

Résumé :

Additional dentition images are needed because the dentitions are distorted in cone-beam computed tomography (CBCT) due to streak artifacts and non-uniformity of the x-ray beam. The purpose of this study is to evaluate the feasibility of improving the dentition image of CBCT scan with intraoral scanner instead of plaster models. Maxilla images from plaster models, two intraoral scanners, and CBCT of 20 patients aged 12 to 18 were used in this study. With one of the intraoral scanners, the full arch was scanned by three segments and combined into a complete full arch. Virtual skull-dentition hybrid images from intraoral scanners were superimposed with the images from plaster models to evaluate the coordinate value difference and distance at reference points. The results showed that the coordinate value difference and distance were smallest with segmented intraoral scan, which showed only 2 ㎛ distance. Intraoral scan may provide good dentition images for virtual skull-dentition images.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Velas, Martin, Michal Spanel, Tomas Sleziak, Jiri Habrovec et Adam Herout. « Indoor and Outdoor Backpack Mapping with Calibrated Pair of Velodyne LiDARs ». Sensors 19, n^o 18 (12 septembre 2019) : 3944. http://dx.doi.org/10.3390/s19183944.

Texte intégral

Résumé :

This paper presents a human-carried mapping backpack based on a pair of Velodyne LiDAR scanners. Our system is a universal solution for both large scale outdoor and smaller indoor environments. It benefits from a combination of two LiDAR scanners, which makes the odometry estimation more precise. The scanners are mounted under different angles, thus a larger space around the backpack is scanned. By fusion with GNSS/INS sub-system, the mapping of featureless environments and the georeferencing of resulting point cloud is possible. By deploying SoA methods for registration and the loop closure optimization, it provides sufficient precision for many applications in BIM (Building Information Modeling), inventory check, construction planning, etc. In our indoor experiments, we evaluated our proposed backpack against ZEB-1 solution, using FARO terrestrial scanner as the reference, yielding similar results in terms of precision, while our system provides higher data density, laser intensity readings, and scalability for large environments.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Borodina, Irina D., Leon S. Grigoryants, Magammed A. Gadzhiev, Svetlana S. Apresyan, Roman V. Batov, Alexander G. Stepanov et Samvel V. Apresyan. « Comparative evaluation of the accuracy of the dental arch display using modern intraoral three-dimensional scanners ». Russian Journal of Dentistry 26, n^o 4 (29 septembre 2022) : 287–97. http://dx.doi.org/10.17816/1728-2802-2022-26-4-287-297.

Texte intégral

Résumé :

BACKGROUND: At present, modern dentists used dental intraoral three-dimensional (3D) scanners routinely in their daily work. Obtaining an optical 3D image of the teeth and dentition helps avoid errors at the stage of obtaining traditional silicone impressions and significantly reduces the level of discomfort during dental procedures. Intraoral scanner systems are commercially available today. Despite their advantages over traditional silicone impressions, the accuracy of the optical impressions obtained during total and subtotal prosthetics on the upper and lower jaw are still questionable. AIM: This study aimed to evaluate the accuracy of scanning models of the patients dentition obtained using intraoral scanners and to determine the currently available models of digital devices that are optimal in terms of price and quality. MATERIAL AND METHODS: The reference scan (master model) was an optical image of the reference model of the upper jaw of a patient with a full dentition made by additive 3D-printing technology obtained using a laboratory scanner. To level out the shrinkage errors of photopolymerization materials, the resulting model was scanned on the same day using intraoral scanners selected for the study. The obtained scan results were compared with the reference scan of the control group. Based on the measurements made at reference points, the average error value relative to the master model and its precision were calculated for each scanner. In addition to the average values, the error parameters of the scanners in the frontal and chewing sections were calculated, as well as the arc error, which was equal to the difference in the values of the discrepancy at the reference points at which the maximum and minimum values were obtained. The cost and availability of scanners on the domestic market, under the sanctions policy of foreign countries, were also considered. RESULTS: The CEREC Primescan AC scanner showed the best accuracy according to the results of model discrepancies. It has an average error of 13.727.34. The arc error was 18.8 microns, and the discrepancies in the frontal area and chewing area were 18 and 6.8 microns, respectively. 3Shape Trios 3 scanner has the closest accuracy, with an average error of 16.285.94 microns. The error value of Aoralscan 3 was 42.0818.34 microns, its arc accuracy was 65 microns, and the discrepancies in the frontal and chewing areas were 33 and 55.1 microns, respectively. Emerald S Mode C had an average error of 35.8422.29 microns, which was higher than that of Medit i500 and Aoralscan 3; however, Aoralscan 3 showed better precision (18.34 microns versus 22.29 microns). According to the comparison results of the models in the MeshLab program, CEREC Primescan AC showed the smallest median of distances (18 microns). The TRIOS 3 and Emerald S Mode C differed from the standard by an average of 29 microns, and Aoralscan 3 scanners had of 33 microns and Medit i500 had 41 microns. CONCLUSION: The precision of Aoralscan 3 scanner, which is the best among its analogs in the price category, makes it the most affordable scanner for dental surgical, orthodontic, and orthopedic fields. CEREC Primescan AC is the leader of the premium scanners involved in the study and available in the dental market.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Son, Keunbada, et Kyu-bok Lee. « Effect of Tooth Types on the Accuracy of Dental 3D Scanners : An In Vitro Study ». Materials 13, n^o 7 (9 avril 2020) : 1744. http://dx.doi.org/10.3390/ma13071744.

Texte intégral

Résumé :

The purpose of this study was to evaluate the accuracy of dental three-dimensional (3D) scanners according to the types of teeth. A computer-aided design (CAD) reference model (CRM) was obtained by scanning the reference typodont model using a high-precision industrial scanner (Solutionix C500, MEDIT). In addition, a CAD test model (CTM) was obtained using seven types of dental 3D scanners (desktop scanners (E1 and DOF Freedom HD) and intraoral scanners (CS3500, CS3600, Trios2, Trios3, and i500)). The 3D inspection software (Geomagic control X, 3DSystems) was used to segment the CRM according to the types of teeth and to superimpose the CTM based on the segmented teeth. The 3D accuracy of the scanner was then analyzed according to the types of teeth. One-way analysis of variance (ANOVA) was used to compare the differences according to the types of teeth in statistical analysis, and the Tukey HSD test was used for post hoc testing (α = 0.05). Both desktop and intraoral scanners showed significant differences in accuracy according to the types of teeth (P < 0.001), and the accuracy of intraoral scanners tended to get worse from anterior to posterior. Therefore, when scanning a complete arch using an intraoral scanner, the clinician should consider the tendency for the accuracy to decrease from anterior to posterior.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Mezei, Adrián, et Tibor Kovács. « Curvature Adaptive 3D Scanning Transformation Calculation ». Periodica Polytechnica Electrical Engineering and Computer Science 62, n^o 4 (13 juin 2018) : 107–16. http://dx.doi.org/10.3311/ppee.11540.

Texte intégral

Résumé :

Three-dimensional objects can be scanned by 3D laser scanners that use active triangulation. These scanners create three-dimensional point clouds from the scanned objects. The laser line is identified in the images, which are captured at given transformations by the camera, and the point cloud can be calculated from these. The hardest challenge is to construct these transformations so that most of the surface can be captured. The result of a scanning may have missing parts because either not the best transformations were used or because some parts of the object cannot be scanned. Based on the results of the previous scans, a better transformation plan can be created, with which the next scan can be performed. In this paper, a method is proposed for transforming a special 3D scanner into a position from where the scanned point can be seen from an ideal angle. A method is described for estimating this transformation in real-time, so these can be calculated for every point of a previous scan to set up a next improved scan.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Velu, Juliëtte F., Erik Groot Jebbink, Jean-Paul PM de Vries, Job AM van der Palen, Cornelis H. Slump et Robert H. Geelkerken. « A phantom study for the comparison of different brands of computed tomography scanners and software packages for endovascular aneurysm repair sizing and planning ». Vascular 26, n^o 2 (18 août 2017) : 198–202. http://dx.doi.org/10.1177/1708538117726648.

Texte intégral

Résumé :

Objectives Correct sizing of endoprostheses used for the treatment of abdominal aortic aneurysms is important to prevent endoleaks and migration. Sizing requires several steps and each step introduces a possible sizing error. The goal of this study was to investigate the magnitude of these errors compared to the golden standard: a vessel phantom. This study focuses on the errors in sizing with three different brands of computed tomography angiography scanners in combination with three reconstruction software packages. Methods Three phantoms with a different diameter, altitude and azimuth were scanned with three computed tomography scanners: Toshiba Aquilion 64-slice, Philips Brilliance iCT 256-slice and Siemens Somatom Sensation 64-slice. The phantom diameters were determined in the stretched view after central lumen line reconstruction by three observers using Simbionix PROcedure Rehearsal Studio, 3mensio and TeraRecon planning software. The observers, all novices in sizing endoprostheses using planning software, measured 108 slices each. Two senior vascular surgeons set the tolerated error margin of sizing on ±1.0 mm. Results In total, 11.3% of the measurements (73/648) were outside the set margins of ±1.0 mm from the phantom diameter, with significant differences between the scanner types (14.8%, 12.1%, 6.9% for the Siemens scanner, Philips scanner and Toshiba scanner, respectively, p-value = 0.032), but not between the software packages (8.3%, 11.1%, 14.4%, p-value = 0.141) or the observers (10.6%, 9.7%, 13.4%, p-value = 0.448). Conclusions It can be concluded that the errors in sizing were independent of the used software packages, but the phantoms scanned with Siemens scanner were significantly more measured incorrectly than the phantoms scanned with the Toshiba scanner. Consequently, awareness on the type of computed tomography scanner and computed tomography scanner setting is necessary, especially in complex abdominal aortic aneurysms sizing for fenestrated or branched endovascular aneurysm repair if appropriate the sizing is of upmost importance.

Styles APA, Harvard, Vancouver, ISO, etc.

31

Ros, A., L. Barrientos, M. Borja-Lloret, J. V. Casaña, E. Muñoz, J. Roser, J. M. Udías, R. Viegas et G. Llosá. « New probe for the improvement of the Spatial Resolution in total-body PET (PROScRiPT) ». EPJ Web of Conferences 253 (2021) : 09004. http://dx.doi.org/10.1051/epjconf/202125309004.

Texte intégral

Résumé :

In recent decades, PET scanners have been widely used for diagnosis and treatment monitoring in nuclear medicine. The continuous effort of the scientific community has led to improvements in scanner performance. Total-body PET is one of the latest upgrades in PET scanners. These kinds of scanners are able to scan the whole body of the patient with a single bed position, since the scanner tube is long enough for the patient to fit inside. While these scanners show unprecedented efficiency and extended field-of-view, a drawback is their low spatial resolution compared to dedicated scanners. In order to improve the spatial resolution of specific areas when measuring with a total-body PET scanner, the IRIS group at IFIC-Valencia is developing a probe. The proposed setup of the probe contains a monolithic scintillation crystal and a SiPM. The signal of the probe is read out by a TOFPET2 ASIC from PETsys, which has shown good performance for PET in terms of spatial and time resolutions. Furthermore, the PETsys technology generates a trigger signal that will be used to time synchronise the probe and the scanner. The proof-of-concept of the probe will be tested in a Preclinical Super Argus PET/CT scanner for small animals located at IFIC. Preliminary simulations of the scanner and the probe under ideal conditions show a slight improvement in the position reconstruction compared to the data obtained with the scanner, therefore we expect a considerable improvement when using the probe in a total-body PET scanner. Characterisation tests of the probe have been performed with a 22Na point-like source, obtaining an energy resolution of 9.09% for the 511 keV energy peak and a temporal resolution of 619 ps after time walk correction. The next step of the project is to test the probe measuring in temporal coincidence with the scanner.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Ruzgienė, Birutė, Renata Bagdžiūnaitė et Vilma Ruginytė. « SCANNING AERIAL PHOTOS USING A NON-PROFESSIONAL SCANNER ». Geodesy and Cartography 38, n^o 3 (1 octobre 2012) : 118–21. http://dx.doi.org/10.3846/20296991.2012.728901.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Maeng, Jiyoun, Young-Jun Lim, Bongju Kim, Myung-Joo Kim et 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^o 6 (20 mars 2019) : 1021. http://dx.doi.org/10.3390/ijerph16061021.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

34

Amornvit, Pokpong, Dinesh Rokaya et Sasiwimol Sanohkan. « Comparison of Accuracy of Current Ten Intraoral Scanners ». BioMed Research International 2021 (13 septembre 2021) : 1–10. http://dx.doi.org/10.1155/2021/2673040.

Texte intégral

Résumé :

There have been various developments in intraoral 3D scanning technology. This study is aimed at investigating the accuracy of 10 scanners developed from 2015 to 2020. A maxillary dental model with reference points was printed from Form 2 (FormLabs, Somerville, MA, USA). The model was scanned 5 times with each intraoral scanner (IOS); Trios 3 (normal and high-resolution mode); Trios 4 (normal and high-resolution mode) (3Shape Trios A/S, Copenhagen, Denmark); iTero Element, iTero 2, and iTero 5D Element (Align Technologies, San Jose, California, USA); Dental Wings (Dental Wings, Montreal QC, Canada); Panda 2 (Pengtum Technologies, Shanghai, China); Medit i500 (Medit Corp. Seoul, South Korea); Planmeca Emerald™ (Planmeca, Helsinki, Finland); and Aoralscan (Shining 3D Tech. Co., Ltd., Hangzhou, China). After the scan, the 3D scanned stereolithography files were created. The various distances were measured five times in X , Y , Z , and X Y axes of various scans and with a vernier caliper (control) and from the Rhinoceros software. The data were analyzed using SPSS 18. Test for the normality of the various measurement data were done using Kolmogorov-Smirnov test. The trueness and precision of the measurements were compared among the various scans using the Kruskal-Wallis test. The significance was considered at P < 0.05 . The trueness of the intraoral scans was analyzed by comparing the measurements from the control. Precision was tested through the measurements of repeated scans. It showed that more the distance is less the accuracy for all scanners. In all studied scanners, the trueness varied but precision was favorably similar. Diagonal scanning showed less accuracy for all the scanners. Hence, when scanning the full arch, the dentist needs to take more caution and good scan pattern. Trios series showed the best scan results compared to other scanners.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Barca, Patrizio, Fabio Paolicchi, Giacomo Aringhieri, Federica Palmas, Daniela Marfisi, Maria Evelina Fantacci, Davide Caramella et Marco Giannelli. « A comprehensive assessment of physical image quality of five different scanners for head CT imaging as clinically used at a single hospital centre—A phantom study ». PLOS ONE 16, n^o 1 (14 janvier 2021) : e0245374. http://dx.doi.org/10.1371/journal.pone.0245374.

Texte intégral

Résumé :

Nowadays, given the technological advance in CT imaging and increasing heterogeneity in characteristics of CT scanners, a number of CT scanners with different manufacturers/technologies are often installed in a hospital centre and used by various departments. In this phantom study, a comprehensive assessment of image quality of 5 scanners (from 3 manufacturers and with different models) for head CT imaging, as clinically used at a single hospital centre, was hence carried out. Helical and/or sequential acquisitions of the Catphan-504 phantom were performed, using the scanning protocols (CTDIvol range: 54.7–57.5 mGy) employed by the staff of various Radiology/Neuroradiology departments of our institution for routine head examinations. CT image quality for each scanner/acquisition protocol was assessed through noise level, noise power spectrum (NPS), contrast-to-noise ratio (CNR), modulation transfer function (MTF), low contrast detectability (LCD) and non-uniformity index analyses. Noise values ranged from 3.5 HU to 5.7 HU across scanners/acquisition protocols. NPS curves differed in terms of peak position (range: 0.21–0.30 mm-1). A substantial variation of CNR values with scanner/acquisition protocol was observed for different contrast inserts. The coefficient of variation (standard deviation divided by mean value) of CNR values across scanners/acquisition protocols was 18.3%, 31.4%, 34.2%, 30.4% and 30% for teflon, delrin, LDPE, polystyrene and acrylic insert, respectively. An appreciable difference in MTF curves across scanners/acquisition protocols was revealed, with a coefficient of variation of f50%/f10% of MTF curves across scanners/acquisition protocols of 10.1%/7.4%. A relevant difference in LCD performance of different scanners/acquisition protocols was found. The range of contrast threshold for a typical object size of 3 mm was 3.7–5.8 HU. Moreover, appreciable differences in terms of NUI values (range: 4.1%-8.3%) were found. The analysis of several quality indices showed a non-negligible variability in head CT imaging capabilities across different scanners/acquisition protocols. This highlights the importance of a physical in-depth characterization of image quality for each CT scanner as clinically used, in order to optimize CT imaging procedures.

Styles APA, Harvard, Vancouver, ISO, etc.

36

Tanner, Mark A., Taigang He, Mark A. Westwood, Renzo Galanello, Gildo Matta, Alan R. Cohen, Mark Fogel et al. « Multi-Centre Validation of the Cardiovascular Magnetic Resonance Multi Breath-Hold T2* Technique for Myocardial Iron Quantification in Thalassaemia Major. » Blood 106, n^o 11 (16 novembre 2005) : 3828. http://dx.doi.org/10.1182/blood.v106.11.3828.3828.

Texte intégral

Résumé :

Abstract Introduction: Beta thalassaemia major (TM) is a hereditary anaemia affecting 60 000 births worldwide each year. Survival is dependent upon lifelong blood transfusions resulting in iron overload. Cardiac siderosis can result in a cardiomyopathy which is the leading cause of death in TM. The validated cardiac magnetic resonance (CMR) T2* technique allows non-invasive and reproducible quantification of myocardial iron. Assessment of myocardial iron loading is essential in determining appropriate chelation therapy. This technique has the potential to become the new gold standard in the assessment of cardiac siderosis but is currently available at only a few sites worldwide. For maximal healthcare benefit its inter-scanner reproducibility must be demonstrated before being widely disseminated. Objective: To demonstrate that CMR T2* quantification of myocardial iron can be reproducibly transferred to MR scanners of different manufacturers in different centres. This project was sponsored by the Thalassemia International Federation. Methods: The previously described multi breath-hold gradient echo T2* technique was installed on MR scanners (all 1.5Tesla) at 6 different centres. Scanner details were as follows: Site 1, Phillips Intera (Turin, Italy), Site 2, Siemens Sonata (Philadelphia, USA), Site 3 GE Signa (Limassol, Cyprus) Site 4, Phillips Intera (Nicosia, Cyprus), Site 5, GE Signa (Cagliari, Sardinia) and Philips Intera (Genova, Italy). 34 patients (mean age 30+/− 5.7years) were scanned in total. All patients were subsequently re-scanned at the standardization centre in London, UK (Siemens Sonata, 1.5T) within 31 days of their original scan. Results: The T2* sequence was successfully installed on all 6 scanners. Myocardial T2* values ranged from 3.6ms to 51ms (14.2 +/− 11ms). The overall inter-scanner reproducibility (SD/mean) was 5.3% (figure 1). The mean difference between T2* values at the standardization centre and visited sites was 0.32ms. Conclusion: We have demonstrated that the multi breath-hold T2* technique for the quantification of myocardial iron can be reproducibly transferred to 1.5T MR scanners at different sites and of different manufacturers. There is therefore real potential to roll out this technique worldwide to facilitate maximal healthcare impact in the management of patients with iron overload conditions such as thalassaemia. Figure Figure

Styles APA, Harvard, Vancouver, ISO, etc.

37

Costa, Vitória, António Sérgio Silva, Rosana Costa, Pedro Barreiros, Joana Mendes et José Manuel Mendes. « In Vitro Comparison of Three Intraoral Scanners for Implant—Supported Dental Prostheses ». Dentistry Journal 10, n^o 6 (15 juin 2022) : 112. http://dx.doi.org/10.3390/dj10060112.

Texte intégral

Résumé :

With continuing technological developments, there have been advances in the field of fixed prosthetics, particularly in impression-taking techniques. These technological advances mean that a wide variety of diagnostic and/or rehabilitation possibilities can be explored without the need for physical models. The aim of this study was to evaluate the accuracy of three intraoral scanners used in oral implant rehabilitation using an extraoral scanner as a reference and varying the scanning area. Three models representing different clinical scenarios were scanned 15 times by each intraoral scanner and three times by the extraoral scanner. The readings were analyzed and overlaid using engineering software (Geomagic® Control X software (Artec Europe, Luxembourg)). Statistically significant differences in accuracy were found between the three intraoral scanners, iTero® (Align Technology Inc., San Jose, CA, USA), Medit® (Medit®: Seoul, Korea), and Planmeca® (Planmeca®: Helsinki, Finland). In all clinical scenarios, the iTero® scanner had the best trueness (24.4 μm), followed by the Medit® (26.4 μm) and Planmeca® (42.1 μm). The Medit® showed the best precision (18.00 μm) followed by the iTero® (19.20 μm) and Planmeca® (34.30 μm). We concluded that the iTero® scanner had the highest reproducibility and accuracy in the clinical setting.

Styles APA, Harvard, Vancouver, ISO, etc.

38

Ozaki, Takashi, Norikazu Ohta et Motohiro Fujiyoshi. « Highly Linear and Wide Non-Resonant Two-Degree-of-Freedom Piezoelectric Laser Scanner ». Sensors 22, n^o 11 (1 juin 2022) : 4215. http://dx.doi.org/10.3390/s22114215.

Texte intégral

Résumé :

Laser scanners with mechanically driven mirrors have exhibited increasing potential for various applications, such as displays and laser radar. Resonant scanners are the predominantly used scanners; however, non-resonant scanners are required for applications where point-to-point driving is desirable. Because a non-resonant drive cannot amplify the drive angle owing to the resonance phenomenon, high values are difficult to achieve for the main performance metrics of the scanners: mirror area, drive angle, and operating frequency. In this paper, we present a two-axis scanner with a piezoelectric actuator made of a piezoelectric single-crystal Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 as the actuation force source. The scanner contains a circular mirror with a diameter of 7 mm and achieves an average static mechanical deflection angle amplitude of 20.8° in two axes with a resonant frequency of 559 Hz. It is equipped with a transmission mechanism that can decouple each axis to achieve high linearity; in our study, the nonlinearity error was less than 1°.

Styles APA, Harvard, Vancouver, ISO, etc.

39

Morris, Keith J. « The Scanning of Colour and B&W Film and Photographs for Image Processing, Analysis and Archiving - On a Tight Budget ». Microscopy Today 14, n^o 3 (mai 2006) : 42–49. http://dx.doi.org/10.1017/s1551929500057667.

Texte intégral

Résumé :

Despite the advent of the new PC based digital camera era, there is still a vast archive of film. The obvious thing to do is to scan film optically using a high resolution film scanner and to convert the image into a digital file for digital distribution, PC archiving, and image processing. The likes of NASA can easily afford the best $20k plus PMT drum scanners and pro flatbed scanners for their spaceflight photo archives. See some professional scanners at http://www.imacon.dk, http://www.aztek.com, http://graphics.kodak.com (Creo) and http://www.flatbed-scanner-review.org. You can download selections from the NASA digitised archive at http://grin.hq.nasa.gov.

Styles APA, Harvard, Vancouver, ISO, etc.

40

Nulty, Adam B. « A Comparison of Full Arch Trueness and Precision of Nine Intra-Oral Digital Scanners and Four Lab Digital Scanners ». Dentistry Journal 9, n^o 7 (23 juin 2021) : 75. http://dx.doi.org/10.3390/dj9070075.

Texte intégral

Résumé :

(1) Background: The purpose of this study is to evaluate the full arch scan accuracy (precision and trueness) of nine digital intra-oral scanners and four lab scanners. Previous studies have compared the accuracy of some intra-oral scanners, but as this is a field of quickly developing technologies, a more up-to-date study was needed to assess the capabilities of currently available models. (2) Methods: The present in vitro study compared nine different intra-oral scanners (Omnicam 4.6; Omnicam 5.1; Primescan; CS 3600; Trios 3; Trios 4; Runyes; i500; and DL206) as well as four lab light scanners (Einscan SE; 300e; E2; and Ineos X5) to investigate the accuracy of each scanner by examining the overall trueness and precision. Ten aligned and cut scans from each of the intra-oral and lab scanners in the in vitro study were brought into CloudCompare. A comparison was made with the master STL using the CloudCompare 3D analysis best-fit algorithm. The results were recorded along with individual standard deviation and a colorimetric map of the deviation across the surface of the STL mesh; a comparison was made to the master STL, quantified at specific points. (3) Results: In the present study, the Primescan had the best overall trueness (17.3 ± 4.9), followed by (in order of increasing deviation) the Trios 4 (20.8 ± 6.2), i500 (25.2 ± 7.3), CS3600 (26.9 ± 15.9), Trios 3 (27.7 ± 6.8), Runyes (47.2 ± 5.4), Omnicam 5.1 (55.1 ± 9.5), Omnicam 4.6 (57.5 ± 3.2), and Launca DL206 (58.5 ± 22.0). Regarding the lab light scanners, the Ineos X5 had the best overall trueness with (0.0 ± 1.9), followed by (in order of increasing deviation) the 3Shape E2 (3.6 ± 2.2), Up3D 300E (12.8 ± 2.7), and Einscan SE (14.9 ± 9.5). (4) Conclusions: This study confirms that all current generations of intra-oral digital scanners can capture a reliable, reproducible full arch scan in dentate patients. Out of the intra-oral scanners tested, no scanner produced results significantly similar in trueness to the Ineos X5. However, the Primescan was the only one to be statistically of a similar level of trueness to the 3Shape E2 lab scanner. All scanners in the study had mean trueness of under 60-micron deviation. While this study can compare the scanning accuracy of this sample in a dentate arch, the scanning of a fully edentulous arch is more challenging. The accuracy of these scanners in edentulous cases should be examined in further studies.

Styles APA, Harvard, Vancouver, ISO, etc.

41

Kang, Byung-hyun, Keunbada Son et Kyu-bok Lee. « Accuracy of Five Intraoral Scanners and Two Laboratory Scanners for a Complete Arch : A Comparative In Vitro Study ». Applied Sciences 10, n^o 1 (20 décembre 2019) : 74. http://dx.doi.org/10.3390/app10010074.

Texte intégral

Résumé :

This study aims to evaluate the accuracy of five different intraoral scanners and two different laboratory scanners for a complete arch. A computer-aided design (CAD) reference model (CRM) was obtained using industrial scanners. A CAD test model (CTM) was obtained using five types of intraoral scanners (CS3500, CS3600, Trios2, Trios3, and i500) and two types of laboratory scanners (3shape E1 and DOF) (N = 20). In addition, the CRM and CTM were superimposed using a 3D inspection software (Geomagic control X; 3D Systems) and 3D analysis was performed. In the 3D analysis, the accuracy was measured by the type of tooth, the anterior and posterior region, and the overall region. As for the statistical analysis of the accuracy, the differences were confirmed using the Kruskal–Wallis H test (α = 0.05). Also, the differences between the groups were analyzed by post-hoc tests including Mann–Whitney U-test and Bonferroni correction method (α = 0.0017). There was a significant difference in the scanning accuracy of the complete arch according to the type of scanner (P < 0.001). The i500 Group showed the lowest accuracy (143 ± 69.6 µm), while the 3Shape E1 Group was the most accurate (14.3 ± 0.3 µm). Also, the accuracy was lower in the posterior region than in the anterior region in all types of scanners (P < 0.001). Scanning accuracy of the complete arch differed depending on the type of scanner. While three types of intraoral scanners (CS3500, CS3600, Trios3) can be recommended for scanning of a complete arch, the two remaining types of intraoral scanners (Trios2 and i500) cannot be recommended.

Styles APA, Harvard, Vancouver, ISO, etc.

42

Tóth, Teodor, Patrik Varga, Branko Štefanovič, Lucia Bednarčíková, Marek Schnitzer, Radovan Hudák et Jozef Živčák. « Accuracy Verification of an Anatomical Model Manufactured Using Low-Cost Additive Production ». Applied Sciences 11, n^o 2 (9 janvier 2021) : 594. http://dx.doi.org/10.3390/app11020594.

Texte intégral

Résumé :

The paper deals with the separation of the third cervical vertebra using the software VGStudio MAX, Mimics, and inVesalius. During the separation, various parameters of the threshold were used to determine the effect. The comparison of models from Mimics and inVesalius to VGStudio MAX showed that the cumulative variance distribution for 95% surface coverage is less than 0.935 mm. When comparing medically oriented software, Mimics and inVesalius, the deviation was less than 0.356 mm. The model was made of polylactic acid (PLA) material on a low-cost 3D printer, Prusa i3 MK2.5 MMU1. The printed model was scanned by four scanners: Artec Eva, 3Shape D700, Steinbichler Comet L3D, and Creaform EXAscan. The outputs from the scanners were compared to the reference model (standard tessellation language (STL) model for 3D printing) as well as to the scanner with the best accuracy (3Shape). Compared to the publications below, the analysis of deviations was evaluated on the entire surface of the model and not on selected dimensions. The cumulative variance distribution for comparing the output from the 3D scanner with the reference model, as well as comparing the scanners, shows that the deviation for 95% of the surface coverage is at the level of 0.300 mm. Since the model of the vertebra is planned for education and training, the used software and technologies are suitable for use in the design and the production process.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Tóth, Teodor, Patrik Varga, Branko Štefanovič, Lucia Bednarčíková, Marek Schnitzer, Radovan Hudák et Jozef Živčák. « Accuracy Verification of an Anatomical Model Manufactured Using Low-Cost Additive Production ». Applied Sciences 11, n^o 2 (9 janvier 2021) : 594. http://dx.doi.org/10.3390/app11020594.

Texte intégral

Résumé :

The paper deals with the separation of the third cervical vertebra using the software VGStudio MAX, Mimics, and inVesalius. During the separation, various parameters of the threshold were used to determine the effect. The comparison of models from Mimics and inVesalius to VGStudio MAX showed that the cumulative variance distribution for 95% surface coverage is less than 0.935 mm. When comparing medically oriented software, Mimics and inVesalius, the deviation was less than 0.356 mm. The model was made of polylactic acid (PLA) material on a low-cost 3D printer, Prusa i3 MK2.5 MMU1. The printed model was scanned by four scanners: Artec Eva, 3Shape D700, Steinbichler Comet L3D, and Creaform EXAscan. The outputs from the scanners were compared to the reference model (standard tessellation language (STL) model for 3D printing) as well as to the scanner with the best accuracy (3Shape). Compared to the publications below, the analysis of deviations was evaluated on the entire surface of the model and not on selected dimensions. The cumulative variance distribution for comparing the output from the 3D scanner with the reference model, as well as comparing the scanners, shows that the deviation for 95% of the surface coverage is at the level of 0.300 mm. Since the model of the vertebra is planned for education and training, the used software and technologies are suitable for use in the design and the production process.

Styles APA, Harvard, Vancouver, ISO, etc.

44

Stangeland, Marcus, Trond Engjom, Martin Mezl, Radovan Jirik, Odd Gilja, Georg Dimcevski et Kim Nylund. « Interobserver Variation of the Bolus-and-Burst Method for Pancreatic Perfusion with Dynamic – Contrast-Enhanced Ultrasound ». Ultrasound International Open 03, n^o 03 (juin 2017) : E99—E106. http://dx.doi.org/10.1055/s-0043-110475.

Texte intégral

Résumé :

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.

Styles APA, Harvard, Vancouver, ISO, etc.

45

Бенуни, А. А., et В. Я. Колючкин. « Компенсация погрешностей модели центральной проекции в трехмерных сканерах ». Журнал технической физики 127, n^o 10 (2019) : 631. http://dx.doi.org/10.21883/os.2019.10.48368.193-19.

Texte intégral

Résumé :

AbstractPinhole model measurement errors in 3D triangulation based scanners is studied in the present work. Pupil aberrations of the scanner lenses are shown to cause noticeable errors in determining the coordinates of surface points. The requirements for aberration characteristics are formulated to minimize the error of 3D scanners. A modification of the pinhole model allowing a decrease in the error induced by pupil aberration of lenses of triangulation-based scanners is proposed as well.

Styles APA, Harvard, Vancouver, ISO, etc.

46

Dlesk, A., K. Vach, J. Šedina et K. Pavelka. « COMPARISON OF LEICA BLK360 AND LEICA BLK2GO ON CHOSEN TEST OBJECTS ». International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVI-5/W1-2022 (3 février 2022) : 77–82. http://dx.doi.org/10.5194/isprs-archives-xlvi-5-w1-2022-77-2022.

Texte intégral

Résumé :

Abstract. The contribution deals with the comparison of two laser scanners manufactured by Leica company. In BIM modelling, there is a need for fast and accurate gathering of spatial data, e.g. point clouds. Those data can be gathered by photogrammetry or laser scanning. Last years on the market, there occurred some light and easy-to-use alternatives to classic laser scanners. There were chosen two scanners that belong to the easy-to-use category. The first scanner is stationary Leica BLK360 and the second scanner is Leica BLK2GO which is a handheld scanner based on SLAM technology. Both laser scanners were tested on three different test objects. The first object is an administrative building, the second object is a historical administrative building and the third object is the vaults of the church. In all cases, only the indoor side of the objects was measured. The point clouds were compared to each other and the comparison was discussed. The parameters derived from the point clouds were also compared to the parameters read in the original documentation of the object. The comparison of the parameters may show, how those point clouds are usable for the final BIM modelling.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Jing, H., N. Slatcher, X. Meng et G. Hunter. « MONITORING CAPABILITIES OF A MOBILE MAPPING SYSTEM BASED ON NAVIGATION QUALITIES ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (6 juin 2016) : 625–31. http://dx.doi.org/10.5194/isprs-archives-xli-b1-625-2016.

Texte intégral

Résumé :

Mobile mapping systems are becoming increasingly popular as they can build 3D models of the environment rapidly by using a laser scanner that is integrated with a navigation system. 3D mobile mapping has been widely used for applications such as 3D city modelling and mapping of the scanned environments. However, accurate mapping relies on not only the scanner’s performance but also on the quality of the navigation results (accuracy and robustness) . This paper discusses the potentials of using 3D mobile mapping systems for landscape change detection, that is traditionally carried out by terrestrial laser scanners that can be accurately geo-referenced at a static location to produce highly accurate dense point clouds. Yet compared to conventional surveying using terrestrial laser scanners, several advantages of mobile mapping systems can be identified. A large area can be monitored in a relatively short period, which enables high repeat frequency monitoring without having to set-up dedicated stations. However, current mobile mapping applications are limited by the quality of navigation results, especially in different environments. The change detection ability of mobile mapping systems is therefore significantly affected by the quality of the navigation results. This paper presents some data collected for the purpose of monitoring from a mobile platform. The datasets are analysed to address current potentials and difficulties. The change detection results are also presented based on the collected dataset. Results indicate the potentials of change detection using a mobile mapping system and suggestions to enhance quality and robustness.

Styles APA, Harvard, Vancouver, ISO, etc.

48

Jing, H., N. Slatcher, X. Meng et G. Hunter. « MONITORING CAPABILITIES OF A MOBILE MAPPING SYSTEM BASED ON NAVIGATION QUALITIES ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (6 juin 2016) : 625–31. http://dx.doi.org/10.5194/isprsarchives-xli-b1-625-2016.

Texte intégral

Résumé :

Mobile mapping systems are becoming increasingly popular as they can build 3D models of the environment rapidly by using a laser scanner that is integrated with a navigation system. 3D mobile mapping has been widely used for applications such as 3D city modelling and mapping of the scanned environments. However, accurate mapping relies on not only the scanner’s performance but also on the quality of the navigation results (accuracy and robustness) . This paper discusses the potentials of using 3D mobile mapping systems for landscape change detection, that is traditionally carried out by terrestrial laser scanners that can be accurately geo-referenced at a static location to produce highly accurate dense point clouds. Yet compared to conventional surveying using terrestrial laser scanners, several advantages of mobile mapping systems can be identified. A large area can be monitored in a relatively short period, which enables high repeat frequency monitoring without having to set-up dedicated stations. However, current mobile mapping applications are limited by the quality of navigation results, especially in different environments. The change detection ability of mobile mapping systems is therefore significantly affected by the quality of the navigation results. This paper presents some data collected for the purpose of monitoring from a mobile platform. The datasets are analysed to address current potentials and difficulties. The change detection results are also presented based on the collected dataset. Results indicate the potentials of change detection using a mobile mapping system and suggestions to enhance quality and robustness.

Styles APA, Harvard, Vancouver, ISO, etc.

49

Celeghin, Giordano, Giulio Franceschetti, Nicola Mobilio, Alberto Fasiol, Santo Catapano, Massimo Corsalini et Francesco Grande. « Complete-Arch Accuracy of Four Intraoral Scanners : An In Vitro Study ». Healthcare 9, n^o 3 (1 mars 2021) : 246. http://dx.doi.org/10.3390/healthcare9030246.

Texte intégral

Résumé :

The purpose of this study is to define the accuracy of four intraoral scanners (IOS) through the analysis of digital impressions of a complete dental arch model. Eight metal inserts were placed on the model as reference points and then it was scanned with a laboratory scanner in order to obtain the reference model. Subsequently, the reference model was scanned with four IOS (Carestream 3600, CEREC Omnicam, True Definition Scanner, Trios 3Shape). Linear measurements were traced on an STL file between the chosen reference points and divided into four categories: three-element mesiodistal, five-element mesiodistal, diagonal, and contralateral measurements. The digital reference values for the measurements were then compared with the values obtained from the scans to analyze the accuracy of the IOS using ANOVA. There were no statistically significant differences between the measurements of the digital scans obtained with the four IOS systems for any of the measurement groups tested.

Styles APA, Harvard, Vancouver, ISO, etc.

50

S. Kamble, Suresh, Ajit S. Jankar, Vidya A. Vaybase, Suraj Sonawane, Pratiksha Somwanshi et Shital Wagh. « DIGITAL DENTISTRY : AN OVERVIEW ON RECENT ADVANCEMENTS IN INTRAORAL SCANNER ». International Journal of Advanced Research 8, n^o 9 (30 septembre 2020) : 1244–50. http://dx.doi.org/10.21474/ijar01/11781.

Texte intégral

Résumé :

New devices are continuously introduced in the clinic and the dental laboratory. The first phase of the digital workflow is to obtain an image with the help of intra-oral scanner. These devices are replacing conventional impressions techniques with the digital scanners. Impressions which are recorded using scanners are more accurate as compared to conventional technique. Intra-oral scanners are time efficient, decrease the patient\'s discomfort and make clinical procedures easier. Over the last few years, there has been new advances in dental scanners for comprehension of computerized work process. Presently in market there are several brands of the scanners with better features to obtain digital impressions, to record the accurate Data in comfortable working time for the dentist and patient. Therefore, it is convenient to analyze the most used IOS systems based on the available scientific data.

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « LE. Scanners »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres