Camera calibration and light source orientation from solar shadows

    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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