Main error sources in ultrasound transmission tomography imaging

1998 ◽  
Vol 103 (5) ◽  
pp. 2793-2793
Author(s):  
Krzysztof J. Opielinski ◽  
Tadeusz Gudra
Keyword(s):  
Transmission Tomography ◽  
Error Sources ◽  
Tomography Imaging ◽  
Main Error

scholarly journals A Study on the Uncertainty of a Laser Triangulator Considering System Covariances

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1630
Author(s):  
Pablo Puerto ◽  
Beñat Estala ◽  
Alberto Mendikute
Keyword(s):  
Error Propagation ◽  
Measurement Accuracy ◽  
Maximum Error ◽  
Experimental Methodology ◽  
Joint Measurement ◽  
Error Sources ◽  
Processing Times ◽  
Main Error ◽  
Laser Plane ◽  
System Variables

A laser triangulation system, which is composed of a camera and a laser, calculates distances between objects intersected by the laser plane. Even though there are commercial triangulation systems, developing a new system allows the design to be adapted to the needs, in addition to allowing dimensions or processing times to be optimized; however the disadvantage is that the real accuracy is not known. The aim of the research is to identify and discuss the relevance of the most significant error sources in laser triangulator systems, predicting their error contribution to the final joint measurement accuracy. Two main phases are considered in this study, namely the calibration and measurement processes. The main error sources are identified and characterized throughout both phases, and a synthetic error propagation methodology is proposed to study the measurement accuracy. As a novelty in uncertainty analysis, the present approach encompasses the covariances of correlated system variables, characterizing both phases for a laser triangulator. An experimental methodology is adopted to evaluate the measurement accuracy in a laser triangulator, comparing it with the values obtained with the synthetic error propagation methodology. The relevance of each error source is discussed, as well as the accuracy of the error propagation. A linearity value of 40 µm and maximum error of 0.6 mm are observed for a 100 mm measuring range, with the camera calibration phase being the main error contributor.

Investigation of the influence of the main error sources on the capacitive displacement measurements with cylindrical artefacts

2013 ◽  
Vol 37 (3) ◽  
pp. 721-737 ◽  
Author(s):  
Hichem Nouira ◽  
Alain Vissiere ◽  
Mohamed Damak ◽  
Jean-Marie David
Keyword(s):  
Error Sources ◽  
Main Error ◽  
Displacement Measurements

The main error sources for pipette dispensers

1988 ◽  
Vol 31 (2) ◽  
pp. 137-138
Author(s):  
A. D. Kuznetsov ◽  
E. V. Pashkevich ◽  
L. I. Golovenchits ◽  
N. K. Akkuratova
Keyword(s):  
Error Sources ◽  
Main Error

Research on Accuracy Analysis and Simulation for Typical Parts with PRS-XY NC Hybrid PMT

2010 ◽  
Vol 148-149 ◽  
pp. 299-303
Author(s):  
Yue Peng Chen ◽  
Hong Wei Fu ◽  
Biao Wang
Keyword(s):  
Inverse Kinematics ◽  
Simulation Software ◽  
Process Models ◽  
Accuracy Analysis ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Error Sources ◽  
Kinematics Model ◽  
Main Error ◽  
Tool Surface

The paper presented a set of PRS-XY hybrid PMT, made up of a set of 3-PRS parallel mechanism and an X-Y table. For advancing the motion accuracy of the PRS-XY type hybrid CNC machine tool, the forward kinematics model and inverse kinematics model have been made, and main error sources affect to machine tool’s precision was established. The relative position of workpiece and the tool of PRS-XY PMT wad discussed, and the coordinate of tool surface was calculated in various process models. The chamfer shape with variation of main error sources was drawn in simulation software, and the processing experiment results prove the correctness of analysis and simulation.

scholarly journals A New Method for Zenith Distance Determination in Meridian Observations

1986 ◽  
Vol 109 ◽  
pp. 557-565 ◽  
Author(s):  
M. Miyamoto ◽  
M. Yoshizawa
Keyword(s):  
Astronomical Observatory ◽  
New Method ◽  
Zenith Distance ◽  
Meridian Circle ◽  
Atmospheric Refraction ◽  
Error Sources ◽  
Distance Determination ◽  
Main Error ◽  
Full Automation

In meridian observations, the main error sources of the declination observation reside in determination of the atmospheric refraction, the flexure of the telescope and the division errors of the graduated circle. In order to obtain higher accuracy in the declination observation, besides a full automation device, the photoelectric meridian circle at Tokyo Astronomical Observatory (Tokyo PMC) is equipped with photoelectric devices for circle reading and a zenith mirror in addition to the conventional mercury horizon. We report here on a preliminary determination of the horizontal and vertical flexures, and of the division errors of the glass circle.

Longitudinal Cut Method Revisited: A Survey on Main Error Sources

2000 ◽  
Vol 44 (02) ◽  
pp. 120-139
Author(s):  
F. Lalli ◽  
F. Di Felice ◽  
P. G. Esposito ◽  
A. Moriconi ◽  
R. Piscopia
Keyword(s):  
Steady Motion ◽  
Numerical Approach ◽  
Wave Pattern ◽  
Resistance Coefficient ◽  
Surface Flow ◽  
Wave Resistance ◽  
Error Sources ◽  
Precision Error ◽  
Main Error ◽  
Cut Method

Some of the main error sources in wave pattern resistance determination were investigated. The experimental data obtained at the Italian Ship Model Basin (longitudinal wave cuts concerned with the steady motion of the Series 60 model and a hard-chine catamaran) were analyzed. It was found that, within the range of Froude numbers tested (0.225 ≤ Fr ≤ 0.345 for the Series 60 and 0.5 < Fr < 1 for the catamaran) two sources of uncertainty play a significant role: (i) the presence of a wave pattern generated by the air pressure disturbance, related to the carriage motion, and (ii) the unsteadiness of the free-surface flow (precision error). The importance of these effects increases, of course, with the model speed. The propagation of experimental errors in the wave resistance determination by the longitudinal cut method was next examined: within the elaboration of measured wave cuts experimental uncertainties are shown to be significantly damped. The wave resistance coefficient can be obtained therefore, with reasonable accuracy, from the measurement uncertainty point of view. Moreover, the errors related to wave cut truncation, as well as to probe transverse location, typical of the longitudinal cut method, were estimated. Systematic tests were performed by means of a numerical approach, which allows one to compare the wave resistance evaluated by the longitudinal cut method (applied in this case to the computed wave pattern) with the value obtained by pressure integration on the hull. As a result, the longitudinal cut method can be applied without introducing any severe limitation for the ratio b/L (tank width over model length), provided the wave cuts are measured at a proper transverse distance.

Ultrasound Transmission Tomography Imaging of Structure of Breast Elastography Phantom Compared to US, CT and MRI

2013 ◽  
Vol 38 (3) ◽  
pp. 321-334 ◽  
Author(s):  
Krzysztof J. Opieliński ◽  
Piotr Pruchnicki ◽  
Tadeusz Gudra ◽  
Przemysław Podgórski ◽  
Tomasz Kraśnicki ◽  
...  
Keyword(s):  
Attenuation Coefficient ◽  
Ultrasound Velocity ◽  
Transmission Tomography ◽  
Tomography Imaging ◽  
Breast Phantom ◽  
Sharp Edges ◽  
X Ray Computed ◽  
Tomography Method ◽  
Ct And Mri ◽  
Breast Elastography

Abstract The paper presents an analysis of the results of ultrasound transmission tomography (UTT) imaging of the internal structure of a breast elastography phantom used for biopsy training, and compares them with the results of CT, MRI and, conventional US imaging; the results of the phantom examination were the basis for the analysis of UTT method resolution. The obtained UTT, CT and MRI images of the CIRS Model 059 breast phantom structure show comparable (in the context of size and location) heterogeneities inside it. The UTT image of distribution of the ultrasound velocity clearly demonstrates continuous changes of density. The UTT image of derivative of attenuation coefficient in relation to frequency is better for visualising sharp edges, and the UTT image of the distribution of attenuation coefficient visualises continuous and stepped changes in an indirect way. The inclusions visualized by CT have sharply delineated edges but are hardly distinguishable from the phantom gel background even with increased image contrast. MRI images of the studied phantom relatively clearly show inclusions in the structure. Ultrasonography images do not show any diversification of the structure of the phantom. The obtained examination results indicate that, if the scanning process is accelerated, ultrasound transmission tomography method can be successfully used to detect and diagnose early breast malignant lesions. Ultrasonic transmission tomography imaging can be applied in medicine for diagnostic examination of women’s breasts and similarly for X-ray computed tomography, while eliminating the need to expose patients to the harmful ionising radiation.

Improvement and Error Analysis of Spring Tube Stiffness Measurement

2014 ◽  
Vol 621 ◽  
pp. 443-449
Author(s):  
Wen Xuan Liu ◽  
Hui Feng Wang ◽  
Guang Lin Wang ◽  
Dong Xiang Shao
Keyword(s):  
Measurement Accuracy ◽  
Error Source ◽  
Element Analysis ◽  
Error Sources ◽  
Stiffness Measurement ◽  
Main Error ◽  
Measure Methods ◽  
Measured Deformation ◽  
Main Components ◽  
The Relationship

This article analyzes the deviation of existing stiffness measurement method and comes to the main components of the measurement error. Focus on the influence of the bending deformation all of aspects and contact deformation between the various links to the measurement accuracy. Establish the relationship between the actual deformation and the measured deformation to the spring tube through homogeneous coordinate transformation and finite element analysis, in order to identify the error sources impact on the measurement greatest, and improve the measure methods to against the main error source, eliminate the influence of the main error source to the stiffness measurement, then achieve the purpose of improving the measure accuracy.

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