ACCURACY OF MEASUREMENTS MADE WITH A CYRAX 2500 LASER SCANNER AGAINST SURFACES OF KNOWN COLOUR

ABSTRACT Objective: To compare the accuracy of measurements obtained from the three-dimensional (3D) laser scans to those taken from the cone-beam computed tomography (CBCT) scans and those obtained from plaster models. Materials and Methods: Eighteen different measurements, encompassing mesiodistal width of teeth and both maxillary and mandibular arch length and width, were selected using various landmarks. CBCT scans and plaster models were prepared from 60 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner, and the selected landmarks were measured using its software. CBCT scans were imported and analyzed using the Avizo software, and the 26 landmarks corresponding to the selected measurements were located and recorded. The plaster models were also measured using a digital caliper. Descriptive statistics and intraclass correlation coefficient (ICC) were used to analyze the data. Results: The ICC result showed that the values obtained by the three different methods were highly correlated in all measurements, all having correlations >0.808. When checking the differences between values and methods, the largest mean difference found was 0.59 mm ± 0.38 mm. Conclusions: In conclusion, plaster models, CBCT models, and laser-scanned models are three different diagnostic records, each with its own advantages and disadvantages. The present results showed that the laser-scanned models are highly accurate to plaster models and CBCT scans. This gives general clinicians an alternative to take into consideration the advantages of laser-scanned models over plaster models and CBCT reconstructions.

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TESTING ACCURACY OF HEIGHT USING A VARIETY OF GEODETIC DEVICES

Proceedings of the 21th Conference for Junior Researchers „Science – Future of Lithuania“ ◽

10.3846/geo.2018.009 ◽

2018 ◽

Author(s):

Aleksandre Lomtadze ◽

Rūta Puzienė

Keyword(s):

Laser Scanner ◽

Measurement Methods ◽

Electronic Timer ◽

Accuracy Of Measurements ◽

Testing Accuracy

In this paper we compare these three methods for testing accuracy of height using a variety of geodetic devices. Each method and device used allows for some precision results. This article examines the extent to which the accuracy of measurements is obtained theoretically, by choosing different measurement methods and different devices, obtained in practice, after measurements, i.e. how many heights measured by different devices will differ from each other. The study of measurements results from the chosen geodetic mark using different geodetic instruments was performed. The following devices are available for testing: GPNS Trimble 5800, Trimble M3 electronic timer, Leica Scan Station C10 laser scanner.

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Reconstruction of Conifer Root Systems Mapped with Point Cloud Data Obtained by 3D Laser Scanning Compared with Manual Measurement

Forests ◽

10.3390/f12081117 ◽

2021 ◽

Vol 12 (8) ◽

pp. 1117

Author(s):

Chikage Todo ◽

Hidetoshi Ikeno ◽

Keitaro Yamase ◽

Toko Tanikawa ◽

Mizue Ohashi ◽

...

Keyword(s):

Root System ◽

Point Cloud ◽

Laser Scanner ◽

Root Systems ◽

Point Cloud Data ◽

Manual Measurement ◽

Cloud Data ◽

Accuracy Of Measurements ◽

Laser Scanners ◽

Point Data

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.

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Large-scale Motion of Solar Filaments

International Astronomical Union Colloquium ◽

10.1017/s0252921100064502 ◽

2000 ◽

Vol 179 ◽

pp. 205-208

Author(s):

Pavel Ambrož ◽

Alfred Schroll

Keyword(s):

Magnetic Flux ◽

Proper Motion ◽

Time Scale ◽

Large Scale ◽

Accuracy Of Measurements ◽

Solar Filaments ◽

General Movement ◽

Scale Motion ◽

Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

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Kinematical and Dynamical CBED Pattern Models: Increasing the Accuracy of the Unit-Cell Parameter Measurements Based on CBED Patterns

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136301 ◽

1990 ◽

Vol 48 (2) ◽

pp. 540-541

Author(s):

I.N. Yadhikov ◽

S.K. Maksimov

Keyword(s):

Reciprocal Lattice ◽

Unit Cell ◽

Reciprocal Lattice Vector ◽

Unit Cell Parameters ◽

Lattice Vector ◽

Cell Parameters ◽

Accuracy Of Measurements ◽

The Difference ◽

Image Position ◽

Convergent Beam

Convergent beam electron diffraction (CBED) is widely used as a microanalysis tool. By the relative position of HOLZ-lines (Higher Order Laue Zone) in CBED-patterns one can determine the unit cell parameters with a high accuracy up to 0.1%. For this purpose, maps of HOLZ-lines are simulated with the help of a computer so that the best matching of maps with experimental CBED-pattern should be reached. In maps, HOLZ-lines are approximated, as a rule, by straight lines. The actual HOLZ-lines, however, are different from the straights. If we decrease accelerating voltage, the difference is increased and, thus, the accuracy of the unit cell parameters determination by the method becomes lower.To improve the accuracy of measurements it is necessary to give up the HOLZ-lines substitution by the straights. According to the kinematical theory a HOLZ-line is merely a fragment of ellipse arc described by the parametric equationwith arc corresponding to change of β parameter from -90° to +90°, wherevector, h - the distance between Laue zones, g - the value of the reciprocal lattice vector, g‖ - the value of the reciprocal lattice vector projection on zero Laue zone.

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Experience of clinical testing of personal telemedicine system ‘Obereg’ for remote monitoring of patients in intensive care units

Medical alphabet ◽

10.33667/2078-5631-2020-13-52-58 ◽

2020 ◽

pp. 52-58 ◽

Cited By ~ 1

Author(s):

A. A. Eryomenko ◽

N. V. Rostunova ◽

S. A. Budagyan ◽

V. V. Stets

Keyword(s):

Intensive Care ◽

Intensive Care Units ◽

Remote Monitoring ◽

Clinical Testing ◽

Transportation Of Patients ◽

High Quality ◽

Telemedicine System ◽

Accuracy Of Measurements ◽

Hospital Equipment

The experience of clinical testing of the personal telemedicine system ‘Obereg’ for remote monitoring of patients at the intensive care units of leading Russian clinics is described. The high quality of communication with the remote receiving devices of doctors, the accuracy of measurements, resistance to interference from various hospital equipment and the absence of its own impact on such equipment were confirmed. There are significant advantages compared to stationary patient monitors, in particular, for intra and out-of-hospital transportation of patients.

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Evaluation of geometrical benchmark artifacts containing multiple overhang lengths fabricated using material extrusion technique

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.14.3.2020.28.0573 ◽

2020 ◽

Vol 14 (3) ◽

pp. 7296-7308

Author(s):

Siti Nur Humaira Mazlan ◽

Aini Zuhra Abdul Kadir ◽

N. H. A. Ngadiman ◽

M.R. Alkahari

Keyword(s):

3D Model ◽

Laser Scanner ◽

Dimensional Accuracy ◽

Fused Deposition Modelling ◽

Layer By Layer ◽

Fused Deposition ◽

Layer Technique ◽

Subtractive Manufacturing ◽

Manufacturing Features ◽

Layer Problem

Fused deposition modelling (FDM) is a process of joining materials based on material entrusion technique to produce objects from 3D model using layer-by-layer technique as opposed to subtractive manufacturing. However, many challenges arise in the FDM-printed part such as warping, first layer problem and elephant food that was led to an error in dimensional accuracy of the printed parts especially for the overhanging parts. Hence, in order to investigate the manufacturability of the FDM printed part, various geometrical and manufacturing features were developed using the benchmarking artifacts. Therefore, in this study, new benchmarking artifacts containing multiple overhang lengths were proposed. After the benchmarking artifacts were developed, each of the features were inspected using 3D laser scanner to measure the dimensional accuracy and tolerances. Based on 3D scanned parts, 80% of the fabricated parts were fabricated within ±0.5 mm of dimensional accuracy as compared with the CAD data. In addition, the multiple overhang lengths were also successfully fabricated with a very significant of filament sagging observed.

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Analysis of Influence of Ephemeris-Time Information on Accuracy of Solving a Navigation Problem by Signals of GLONASS System

Proceedings of Universities ELECTRONICS ◽

10.24151/1561-5405-2020-25-5-465-474 ◽

2020 ◽

Vol 25 (5) ◽

pp. 465-474

Author(s):

V.O. Zhilinskiy ◽

◽

D.S. Pecheritsa ◽

L.G. Gagarina ◽

◽

...

Keyword(s):

High Precision ◽

Satellite Navigation ◽

Satellite System ◽

Navigation Systems ◽

Navigation Problem ◽

Satellite Navigation System ◽

Study Results ◽

Accuracy Of Measurements ◽

Huge Impact ◽

Time Information

The Global Navigation Satellite System has a huge impact on both the public and private sectors, including the social-economic development, it has many applications and is an integral part of many domains. The application of the satellite navigation systems remains the most relevant in the field of transport, including land, air and maritime transport. The GLONASS system consists of three segments and the operation of the entire system depends on functioning of each component, but primarily, the accuracy of measurements depends on the basis forming of the control segment and management, responsible for forming ephemeris-time information. In the work, the influence of ephemeris-time information on the accuracy of solving the navigation problem by the signals of the GLONASS satellite navigation system has been analyzed. The influence of both ephemeris information and the frequency information, and of the time corrections has been individually studied. The accuracy of the ephemeris-time information is especially important when solving the navigation problem by highly precise positioning method. For the analysis the following scenarios of the navigation problem solving have been formed: using high-precision and broadcast ephemeris-time information, a combination of broadcast (high-precision) ephemeris-time information, and high-precision (broadcast) satellite clock offsets and two scenarios with simulation of the calculation of the relative correction to the radio signal carrier frequency. Based on the study results it has been concluded that the contribution of the frequency-time corrections to the error of location determination is of the greatest importance and a huge impact on the error location, while the errors of the ephemeris information are insignificant

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THREE-DIMENSIONAL ASSESSMENT OF SWELLING IN ORTHOGNATHIC SURGERY USING THE SURFACE LASER SCANNER: FUSION WITH THREE-DIMENSIONAL COMPUTED TOMOGRAPHY

10.26226/morressier.578e3b4fd462b8029238257e ◽

2016 ◽

Author(s):

Satoshi Yamamoto

Keyword(s):

Computed Tomography ◽

Orthognathic Surgery ◽

Three Dimensional ◽

Laser Scanner ◽

Surface Laser ◽

Dimensional Assessment

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Evaluation of the accuracy indicators in determination of the coating thickness by crater grinding method

Industrial laboratory Diagnostics of materials ◽

10.26896/1028-6861-2020-86-7-39-44 ◽

2020 ◽

Vol 86 (7) ◽

pp. 39-44

Author(s):

K. V. Gogolinsky ◽

A. E. Ivkin ◽

V. V. Alekhnovich ◽

A. Yu. Vasiliev ◽

A. E. Tyurnina ◽

...

Keyword(s):

Coating Thickness ◽

Functional Dependence ◽

Measurement Procedure ◽

Metrological Certification ◽

Measuring Instruments ◽

Properties Of Coatings ◽

Special Equipment ◽

Grinding Method ◽

Accuracy Of Measurements ◽

Wide Range

Thickness is one of the key indicators characterizing the quality and functional properties of coatings. Various indirect methods (electromagnetic, radiation, optical) most often used in practice to measure thickness are based on the functional dependence of a particular physical parameter of the system «base – coating» on the coating thickness. The sensitivity of these procedures to the certain properties of coatings imposes the main restriction to the accuracy of measurements. Therefore, the development and implementation of the approaches based on direct measurements of geometric parameters of the coating appears expedient. These methods often belong to the class of «destructive» and, in addition to measuring instruments, require the use of special equipment. To ensure the uniformity of measurements in the laboratory or technological control, these methods are isolated as a separate procedure (method) and must undergo metrological certification in accordance with GOST R 8.563–2009. We present implementation, metrological certification and practical application of the method for measuring thickness of coatings by crater-grinding method. The principles of technical implementation of test equipment, measurement procedure and calculation formulas are described. The results of evaluating the accuracy indicators of the proposed procedure by calculation and experimental methods are presented. In both cases, the relative error did not exceed 6%. The applicability of the developed technique is shown for a wide range of coating materials (from soft metals to superhard ceramics) of different thickness (with from units to hundreds of micrometers). Apart from the goals of process control and outgoing inspection, the method can be recommended as a reference measurement procedure for calibration of measures and adjusting samples for various types of thickness gauges.

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