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Showing papers on "Perspective (geometry) published in 1993"


Proceedings ArticleDOI
15 Jun 1993
TL;DR: The problem of matching perspective views of coplanar structures composed of line segments is considered and both model-to-image and image- to-image correspondence matching are given a consistent treatment.
Abstract: The problem of matching perspective views of coplanar structures composed of line segments is considered. Both model-to-image and image-to-image correspondence matching are given a consistent treatment. These matching scenarios generally require discovery of an eight-parameter projective mapping. When the horizon line of the object plane can be found in the image, which is accomplished in this case by using vanishing point analysis, these problems reduce to a simpler six-parameter affine matching problem. When the intrinsic lens parameters of the camera are known, the problem further reduces to four-parameter affine similarity matching. >

56 citations


Journal ArticleDOI
TL;DR: In this article, the relevance of perspective geometry for 3D scene analysis from a single view is asserted, and analytic procedures for perspective inversion of special primitive configurations are presented, including four coplanar segments, three orthogonal segments, a circle arc, and a quadric of revolution.
Abstract: In this paper the relevance of perspective geometry for 3D scene analysis from a single view is asserted. Analytic procedures for perspective inversion of special primitive configurations are presented. Four configurations are treated: (1) four coplanar segments; (2) three orthogonal segments; (3) a circle arc; (4) a quadric of revolution. A complete and thorough illustration of the developed methodologies is given. The importance of the selected primitives is illustrated in different application contexts. Experimental results on real images are provided for configurations (3) and (4).

41 citations


Journal ArticleDOI
TL;DR: This paper presents a method of camera calibration in which camera parameters are determined by a set of 3D lines, which generalizes that of Liu, Huang and Faugeras for camera location determination in which at least 8 line correspondences are required for linear computation of camera location.
Abstract: The basic idea of calibrating a camera system in previous approaches is to determine camera parameters by using a set of known 3D points as calibration reference In this paper, we present a method of camera calibration in which camera parameters are determined by a set of 3D lines A set of constraints is derived on camera parameters in terms of perspective line mapping From these constraints, the same perspective transformation matrix as that for point mapping can be computed linearly The minimum number of calibration lines is 6 This result generalizes that of Liu, Huang and Faugeras[12] for camera location determination in which at least 8 line correspondences are required for linear computation of camera location Since line segments in an image can be located easily and more accurately than points, the use of lines as calibration reference tends to ease the computation in image preprocessing and to improve calibration accuracy Experimental results on the calibration along with stereo reconstruction are reported

8 citations


Proceedings ArticleDOI
15 Jun 1993
TL;DR: It is shown that orientations from skew symmetry can be reliably determined and accurate line parameter estimates are used to determine orientations in an image scene using skew symmetry.
Abstract: Straight lines from a single perspective image are used to determine orientations of objects in an image scene using skew symmetry. The lines are detected using a Hough transform followed by an optimization algorithm in order to remove discretization errors in the line parameters. The use of these accurate line parameter estimates is demonstrated with some test images for which the plane orientations are known. It is shown that orientations from skew symmetry can be reliably determined. >

5 citations



10 Jan 1993
TL;DR: In this article, a set of constraints is derived on camea parameters in terms of perspective line mapping, and the same perspective transformation matrix as that for point mapping can be computed linearly.
Abstract: The basic idea of calibrating a camera system in previous approaches is to determine camera parmeters by using a set of known 3D points as calibration reference.In this paper,we present a method of camera calibration in whih camera parameters are determined by a set of 3D lines.A set of constraints is derived on camea parameters in terms of perspective line mapping.Form these constraints,the same perspective transformation matrix as that for point mapping can be computed linearly.The minimum number of calibration lines is 6.This result generalizes that of Liu,Huang and Faugeras^[12] for camera location determination in which at least 8 line correspondences are required for linear computation of camera location.Since line segments in an image can be located easily and more accurately than points,the use of lines as calibration reference tends to ease the computation in inage preprocessing and to improve calibration accuracy.Experimental results on the calibration along with stereo reconstruction are reported.

1 citations


Posted Content
TL;DR: In this paper, four-dimensional Euclidean spaces that solve Einstein's equations are interpreted as WKB approximations to wavefunctionals of quantum geometry, represented graphically by suppressing inessential dimensions and drawing the resulting figures in perspective representation of three-dimensional space.
Abstract: Four-dimensional Euclidean spaces that solve Einstein's equations are interpreted as WKB approximations to wavefunctionals of quantum geometry. These spaces are represented graphically by suppressing inessential dimensions and drawing the resulting figures in perspective representation of three-dimensional space, some of them stereoscopically. The figures are also related to the physical interpretation of the corresponding quantum processes.

1 citations