Results 291 to 300 of about 693,780 (338)

Geometric accuracy of the NewTom 9000 Cone Beam CT

Dentomaxillofacial Radiology, 2005
To determine the geometric accuracy of digital volume tomograms to assess their usability for implant planning.A measuring object with 216 measuring points, whose geometry is exactly known, is X-rayed with a NewTom 9000 cone beam scanner; thereafter the geometry of the volume tomogram of the object is compared with the original body.Considering all ...
R, Marmulla, R, Wörtche, J, Mühling, S, Hassfeld   +3 more
openaire   +4 more sources

Geometric Accuracy of Intravascular Ultrasound Imaging

Journal of the American Society of Echocardiography, 1992
In spite of the current interest in and clinical application of intravascular ultrasound imaging, there is very little published information on the limitations of this modality. In vitro studies on nine phantom vessels (diameter 4.76 to 12.7 mm) and 11 human arteries (diameter 3.7 to 6.2 mm) were performed to assess the potential sources of error of ...
J S, Chae, A F, Brisken, G, Maurer, R J, Siegel   +3 more
openaire   +2 more sources

Geometric Accuracy of Three-Dimensional Molecular Overlays

Journal of Chemical Information and Modeling, 2006
This study examines the dependence of molecular alignment accuracy on a variety of factors including the choice of molecular template, alignment method, conformational flexibility, and type of protein target. We used eight test systems for which X-ray data on 145 ligand-protein complexes were available.
Qi, Chen, Richard E, Higgs, Michal, Vieth   +2 more
openaire   +2 more sources

Enhancement of geometric accuracy via an intermediate geometrical feedback scheme

Journal of Manufacturing Systems, 1999
Abstract To enhance the geometric accuracy of a machined part, both the static and dynamic errors present in the NC machining procedure should be handled in some manner. This paper presents systematic compensation methods for these errors based on an intermediate geometrical feedback scheme.
Suh, SH, Lee, ES, Sohn, JW
openaire   +2 more sources

Geometric accuracy of reconstructed PET images

1998 IEEE Nuclear Science Symposium Conference Record. 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference (Cat. No.98CH36255), 2002
The registration of multimodality brain studies (PET & MRI) requires geometrically identical properties of the acquired images. In particular, if pixel by pixel manipulations are performed, e.g., for partial volume corrections of PET images, geometrical discrepancies in the images of one modality lead to erroneous results.
E.R. Kops, T. Schmitz, H. Herzog
openaire   +1 more source

Geometric accuracy in airborne SAR images

IEEE Transactions on Aerospace and Electronic Systems, 1989
Uncorrected across-track motions of a synthetic aperture radar (SAR) platform can cause both a severe loss of azimuthal positioning accuracy in, and defocusing of, the resultant SAR image. It is shown how the results of an autofocus procedure can be incorporated in the azimuth processing to produce a fully focused image that is geometrically accurate ...
D. Blacknell, A. Freeman, S. Quegan, I.A. Ward, I.P. Finley, C.J. Oliver, R.G. White, J.W. Wood   +7 more
openaire   +1 more source

Accuracy of Geometric Estimation

2016
We focus here on algebraic methods for ellipse fitting, fundamental matrix computation, and homography computation described in Chaps. 2, 3, and 6 in a more generalized mathematical framework. We do a detailed error analysis in general terms and derive explicit expressions for the covariance and bias of the solution. The hyper-renormalization procedure
Kenichi Kanatani, Yasuyuki Sugaya, Yasushi Kanazawa   +2 more
openaire   +1 more source

Accuracy of Geometric Channel-Modeling Methods

IEEE Transactions on Vehicular Technology, 2004
When constructing a propagation channel model, a substitute is often created by giving an arbitrary shape or form to scatterer distributions based on its intuitive appeal for a certain radio environment. However, such models do not necessarily represent the actual propagation process and may yield inaccurate results. The main objective of this paper is
Y. Chen, V.K. Dubey
openaire   +1 more source

Geometric Accuracy Evaluation of GF-7 Image

2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, 2021
We selected a scene of “GF-7” satellite multispectral rear-view camera image in Chengdu, Sichuan Province of China. At the same time, we take 26 high-precision GPS sampling points evenly distributed in the region as control points, and make statistics on the geometric positioning accuracy of images.
Li Guoming, Li Guoqing, Wang Tianqing
openaire   +1 more source