3-D Surface Description Using Curvature Properties

1987 ◽  
Author(s):  
T. J. Fan ◽  
G. Medioni ◽  
R. Nevatia
Keyword(s):  
Surface Description

Inspection and Feature Extraction of Marine Propellers

1993 ◽  
Vol 9 (02) ◽  
pp. 88-106
Author(s):  
Richard A. Jinkerson ◽  
Stephen L. Abrams ◽  
Leonidas Bardis ◽  
Chryssostomos Chryssostomidis ◽  
Andre Cldment ◽  
...  
Keyword(s):  
Rigid Body ◽  
Nonlinear Differential Equations ◽  
Leading Edge ◽  
Propeller Blade ◽  
Offset Distance ◽  
Surface Description ◽  
Euclidean Motion ◽  
Rigid Body Transformation ◽  
Thickness Function ◽  
The Ideal

Localization is the process of determining the rigid-body translations and rotations that must be performed on the set of points measured on a manufactured surface to move those points into closest correspondence with the ideal design surface. In unconstrained localization all points have equal effect on the determination of the rigid-body transformation, while constrained localization allows a subset of the points to have stronger influence on the transformation. The measured points are physical points in space obtained by direct measurement of a manufactured marine propeller blade. The ideal design surface is the surface description of the propeller blade provided by the blade designer. Given that the measured blade is manufactured from the design surface description, the localization determines a Euclidean motion that brings the measured points of the manufactured surface as close as possible to the design surface. An additional option is to determine an offset distance, such that the Euclidean motion brings the measured points as close as possible to the offset of the design surface. For this optimization problem the offset distance is a seventh parameter that must be determined in addition to the six parameters of the Euclidean motion. After localization, the offset of the design surface that was determined can be used to extract the gross geometric features of the manufactured blade. These features have important hydrodynamic functions and include the camber surface, section thickness function, pitch, rake, skew, chord length, maximum thickness, maximum camber, and the leading-edge curve. The approximation of the camber surface, which is the basis of most of the remaining features, is an intricate problem relying on an extension of the concept of a Brooks ribbon. It requires the solution of a system of nonlinear differential equations and a complicated error evaluation scheme.

Logical atomism

2018 ◽  
Author(s):  
Alex Oliver
Keyword(s):  
Mutual Influence ◽  
Ordinary Language ◽  
Common Theme ◽  
Complex Sentences ◽  
Logical Atomism ◽  
The First World War ◽  
The World ◽  
Surface Description ◽  
The Common ◽  
First World

The name ‘logical atomism’ refers to a network of theses about the parts and structure of the world and the means by which language represents the world. Wittgenstein, in his Tractatus Logico-Philosophicus, expounds a version of logical atomism developed by him around the time of the First World War, as does Russell in works published contemporaneously. It is no accident that their work on logical atomism shares a common surface description since it resulted from their mutual influence at Cambridge. The common theme is that the meaning of our sentences is rooted in a primitive relation between simple expressions and their simple worldly bearers, the logical atoms. In a logically perfect language, atomic sentences describe configurations of these atoms, and complex sentences are combinations of the atomic sentences. But sentences of ordinary language may have a misleading surface form which is revealed as such by analysis. The common theme masks considerable differences of doctrine. In particular, there are differences in the nature of logical atoms and in the arguments for the existence of these atoms.

Hierarchical triangulation for multiresolution surface description

1995 ◽  
Vol 14 (4) ◽  
pp. 363-411 ◽  
Author(s):  
Leila De Floriani ◽  
Enrico Puppo
Keyword(s):  
Surface Description

SURFACE DESCRIPTION FOR CORNEA TOPOGRAPHY USING MODIFIED CHEBYSHEV-POLYNOMIALS

2005 ◽  
Vol 38 (1) ◽  
pp. 325-330
Author(s):  
Alexandros Soumelidis ◽  
Zoltán Fazekas ◽  
Ferenc Schipp ◽  
János Németh
Keyword(s):  
Chebyshev Polynomials ◽  
Surface Description

Power Spectrum for Surface Description of Corroded Ship Structure From Laser Scan

2019 ◽  
Author(s):  
Karoline M. Neumann ◽  
Sören Ehlers
Keyword(s):  
Power Spectrum ◽  
Material Properties ◽  
Power Spectra ◽  
Surface Pattern ◽  
Average Thickness ◽  
Marine Structures ◽  
Ship Structure ◽  
Fatigue Initiation ◽  
Ordinate Axis ◽  
Surface Description

Abstract Strength of corroded marine structures is in the industry traditionally assessed using average thickness reduction together with the assumption of a uniform surface. In academia it is however realised that the surface texture will influence the strength where the effect of the irregular surface is considered through various parameters such as reduced material properties, roughness, geometrical ratios and thickness distributions. In this paper, the objective is to present a power spectrum which describes the corroded surface topography. Therefore, power spectra of surface and thickness are produced from 3D laser scan of real corroded mild steel specimens from a 30 year old ship using Fast Fourier Transform (FFT). The frequency distribution describes the spatial variability, wherefrom the autocorrelation function (ACF) is deduced. A log-log fit is made to the power spectrum, where the interception with the ordinate axis describes the corrosion severity. This way of describing the surface pattern of the corrosion deterioration may serve as input to novel ways of calculating corroded strength and fatigue initiation as well as simulation of corroded surfaces.

scholarly journals ECHO: Extended Convolution Histogram of Orientations for Local Surface Description

2020 ◽  
Author(s):  
Thomas W. Mitchel ◽  
Szymon Rusinkiewicz ◽  
Gregory S. Chirikjian ◽  
Michael Kazhdan
Keyword(s):  
Local Surface ◽  
Surface Description

Local Interpolation for Tools Surface Description

2010 ◽  
Author(s):  
D. M. Neto ◽  
M. C. Oliveira ◽  
J. L. Alves ◽  
L. F. Menezes ◽  
F. Barlat ◽  
...  
Keyword(s):  
Local Interpolation ◽  
Surface Description
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