Quality assessment and deviation analysis of three-dimensional geometrical characterization of a metal pipeline by pulse-echo ultrasonic and laser scanning techniques

Measurement ◽  
2019 ◽  
Vol 145 ◽  
pp. 30-37 ◽  
Author(s):  
Bruno Silva Marció ◽  
Philipp Nienheysen ◽  
Daniel Habor ◽  
Rodolfo C.C. Flesch
Keyword(s):  
Quality Assessment ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Geometrical Characterization ◽  
Deviation Analysis ◽  
Pulse Echo

An Automated Procedure for the Geometrical Characterization of Root Canals

2008 ◽  
Author(s):  
Giovanni Tani ◽  
Leonardo Orazi ◽  
Gabriele Cuccolini
Keyword(s):  
Measurement System ◽  
Laser Scanning ◽  
Original System ◽  
Maximum Amount ◽  
Computer Design ◽  
Geometrical Characterization ◽  
Statistical Population ◽  
Root Canals ◽  
Best Fit

In this work an original system for the geometrical characterization of root canals for dental implants was developed and tested. The aim of this work is to determine the shape and the size of the posts that best fit a statistical population of root canals with a defined maximum amount of removed tissue. The task is performed by an accurate acquisition of the shape of a statistically significant batches of root impressions: the geometry are then processed to obtain the post geometry. The acquisition is carried out using a conoscopic laser scanning device mounted on a 4 axis controlled CNC measurement system. The shape of the root canals were measured for each type of tooth, obtaining an average 3-D computer design of the canal profiles. Several comparisons between the acquired geometry and the representative forms of commercial posts are finally presented.

THE GEOMETRICAL CHARACTERIZATION OF NEURAL ACTIVITY DISPLAYS A SENSITIVITY TO CONVULSANTS

1991 ◽  
Vol 01 (01) ◽  
pp. 253-259 ◽  
Author(s):  
I. D. ZIMMERMAN ◽  
P. E. RAPP ◽  
A. I. MEES
Keyword(s):  
Interspike Interval ◽  
Three Dimensional ◽  
Interval Data ◽  
Time Intervals ◽  
Geometrical Characterization ◽  
Single Nerve ◽  
Before And After ◽  
The Mean ◽  
Standard Techniques

Direct application of a drop of penicillin to the brain's surface can elicit brain electrical activity similar to that seen in some forms of epilepsy. The procedure has therefore become one of the standard techniques in the experimental investigation of epilepsy. The time intervals between action potentials, called the interspike intervals, were measured from single nerve cells in the cerebral cortex of the rat before and after local administration of penicillin. The resulting interspike interval data were examined by elementary statistical procedures and by embedding the data in two- and three-dimensional spaces. The mean interspike interval did not change significantly in response to penicillin. In contrast, the geometrical characterization displayed a dramatic sensitivity to the drug.

scholarly journals EVALUATING MOBILE LASER SCANNING FOR LANDSLIDE MONITORING

2018 ◽  
Vol XLII-3/W4 ◽  
pp. 211-219
Author(s):  
N. A. Fuad ◽  
A. R. Yusoff ◽  
M. P. M. Zam ◽  
A. Aspuri ◽  
M. F. Salleh ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Human Life ◽  
Three Dimensional ◽  
Landslide Monitoring ◽  
Landslide Area ◽  
Project Area ◽  
Deviation Analysis ◽  
Gps Survey ◽  
Surface Deviation ◽  
Dimensional Surface

<p><strong>Abstract.</strong> Landslide is one of the natural disasters that give a huge impact to human life and social-economic development. Landslide needs to be monitored periodically in order to avoid loss of human life and damages of properties. Various methods have been used for monitoring landslide. This aim of the research is to evaluate the potential of mobile laser scanning technique for monitoring of landslide area. The objectives of the research are to acquire three-dimensional surface data of landslide area in different epochs and to analyze the movement of the landslide area using three-dimensional surface deviation and ground surveying techniques. The methodology begins with the GPS survey for the establishment of ground control points for the project area. The total station survey was then carried out to measure the three-dimensional coordinates of twenty well distributed targets located at the project area. The data collection phase was then continuing with the mobile laser scanning survey. The processing of the two epochs data acquired from both techniques was then carried out simultaneously and the methodology concluded with the output comparison analysis for the movement detection of the land slip. The finding shows that the mobile laser scanning provides fast and accurate data acquisition technique of the landslide surface. The surface deviation analysis of the two epochs laser scanning data was capable to detect the movement occurred in the project area. The results were successfully evaluated using the changes of the three-dimensional coordinates of the targets from the two epoch’s ground surveying data.</p>

Three-Dimensional Geometrical Characterization of Cerebral Aneurysms

2004 ◽  
Vol 32 (2) ◽  
pp. 264-273 ◽  
Author(s):  
Baoshun Ma ◽  
Robert E. Harbaugh ◽  
Madhavan L. Raghavan
Keyword(s):  
Three Dimensional ◽  
Cerebral Aneurysms ◽  
Geometrical Characterization

scholarly journals Accuracy of Models Obtained from Digital Impressions Versus Scanning of Conventional Impressions

2021 ◽  
Author(s):  
Noha M. Elkersh ◽  
Rania A.Fahmy ◽  
Mohamed K. Zayet ◽  
Yousria S. Gaweesh
Keyword(s):  
Repeated Measures ◽  
Laser Scanning ◽  
Visual Analysis ◽  
Three Dimensional ◽  
Digital Model ◽  
Linear Measurements ◽  
Deviation Analysis ◽  
Digital Impressions ◽  
Mean Differences

Abstract Background Digital workflow has invaded the different dental specialities. It includes some steps, the first of them is the scan process and dental modelling. Many methods are available for digital model fabrication. Therefore, the aim of this in vivo study to assess and compare the accuracy of 3-dimensional (3D) digital dental models obtained from scanning of conventional impressions versus models from digital impressions. Materials and Methods Three-dimensional digital model files were obtained in vivo from three different methods including scanning of impressions by both Cone beam computed tomography (CBCT) machine (Veraview x800, JMorita) and desktop scanner (Smart optics, Vinyl Open Air). The same volunteers have received digital impressions by an intraoral scanner (CS3600). Six linear measurements were measured in each Stereolithography (STL) model and compared with direct calliper measurements. Additionally, STL files from the three systems were paired and superimposed using a best-fit algorithm in a 3D modelling software. Mean deviations between the STL shells were calculated by the software and color maps were obtained for visual analysis. Intra-class correlation coefficient (ICC) was calculated to determine the intra-examiner reliability. Paired t-test, ANOVA with repeated measures and Post Hoc test (Bonferroni adjusted) were used in the statistical analysis. Significance of the obtained results was judged at the 5% level. Results The linear measurements and 3D deviation analysis revealed significant differences in some measurements but were considered clinically accepted. Digital models obtained from laser scanning of the impressions revealed the least mean differences from the gold standard ranging from (-0.24 to 0.01 mm), while CBCT scanning of the impressions mean differences ranged from (0.16 to -0.04 mm). IOS revealed the highest mean differences ranging from (0.11 to 0.33 mm). Conclusion Scanning the impression with a desktop scanner provided the highest accuracy in full arch scans followed by scanning with CBCT but with decreased surface texture of the 3D mesh. While intraoral scanners showed the least accuracy for full arch scans up till now and need further improvement in their technology. All techniques can be applied in clinical practice providing the use of high quality machines.

Geometrical characterization of canted coil springs

2006 ◽  
Vol 220 (12) ◽  
pp. 1831-1841
Author(s):  
J M Soler ◽  
R H Rangel
Keyword(s):  
Computer Aided Design ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Helical Spring ◽  
Element Analysis ◽  
Geometrical Characterization ◽  
Three Dimensional Models ◽  
Curvature And Torsion ◽  
Aided Design

This article presents a geometrical description of canted coil springs as a particular type of space curve. The influence of the canted angle on the geometrical curvature and torsion is investigated in order to characterize the three-dimensional geometry of the springs. Geometrical descriptions of helical spring rings generated by joining together the two ends of a rectilinear-axis spring as well as several types of spring rings, obtained from rectilinear-axis canted coil springs, are proposed. To create such ring geometries, conservation of length of wire is assumed and approximate relations are derived in order to simplify computations. These geometrical descriptions are then applied to generate appropriate three-dimensional models. Such models can be further imported to computer-aided design and finite-element analysis programmes in order to estimate the mechanical response of such springs.

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