Title

Camera calibration and light source orientation from solar shadows

Authors

Authors

X. C. Cao;H. Foroosh

Comments

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Abbreviated Journal Title

Comput. Vis. Image Underst.

Keywords

camera calibration; solar shadow; light source orientation estimation; planar homology; SELF-CALIBRATION; POINTS; VIEW; RECONSTRUCTION; REVOLUTION; SURFACES; GEOMETRY; Computer Science, Artificial Intelligence; Engineering, Electrical &; Electronic

Abstract

In this paper, we describe a method for recovering camera parameters from perspective views of daylight shadows in a scene, given only minimal geometric information determined from the images. This minimal information consists of two 3D stationary points and their cast shadows on the ground plane. We show that this information captured in two views is sufficient to determine the focal length, the aspect ratio, and the principal point of a pinhole camera with fixed intrinsic parameters. In addition, we are also able to compute the orientation of the light source. Our method is based on exploiting novel inter-image constraints on the image of the absolute conic and the physical properties of solar shadows. Compared to the traditional methods that require images of some precisely machined calibration patterns, our method uses cast shadows by the sun, which are common in natural environments, and requires no measurements of any distance or angle in the 3D world To demonstrate the accuracy of the proposed algorithm and its utility, we present the results on both synthetic and real images, and apply the method to an image-based rendering problem. (c) 2006 Elsevier Inc. All rights reserved.

Journal Title

Computer Vision and Image Understanding

Volume

105

Issue/Number

1

Publication Date

1-1-2007

Document Type

Article

Language

English

First Page

60

Last Page

72

WOS Identifier

WOS:000243460900005

ISSN

1077-3142

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