Back to articles
Articles
Volume: 9 | Article ID: art00005
Image
Measurement of Omnidirectional Light Distribution by a Mirrored Ball
  DOI :  10.2352/CIC.2001.9.1.art00005  Published OnlineJanuary 2001
Abstract

Illuminant estimation in natural scenes includes the problem of estimating a spatial distribution of light sources by omnidirectional observations. The present paper describes a method for estimating an omnidirectional light distribution from the image of a camera aiming at a mirrored ball. The parameters including the camera location in the scene and the focal length of the camera lens are estimated to precisely determine the mapping between coordinates on the ball and light rays in the world. We create two types of image to represent the omnidirectional light distribution in the world. One representation is a polar coordinate system with the origin located at the center of the mirrored ball. The other is a parallel projection on a two-dimensional screen passing the center of the ball. Experiments in a natural scene using a spherical steel ball and a color CCD camera are described. First, we estimate an omnidirectional radiance distribution indoors in a room with fluorescent ceiling lights. Second, we estimate the radiance distribution in the open air. The scene includes strong specular high light by direct reflection of sunlight. We analyze the chromaticity of the omnidirectional light source.

Subject Areas :
Views 6
Downloads 0
 articleview.views 6
 articleview.downloads 0
  Cite this article 

Shoji Tominaga, Norihiro Tanaka, "Measurement of Omnidirectional Light Distribution by a Mirrored Ballin Proc. IS&T 9th Color and Imaging Conf.,  2001,  pp 22 - 26,  https://doi.org/10.2352/CIC.2001.9.1.art00005

 Copy citation
  Copyright statement 
Copyright © Society for Imaging Science and Technology 2001
72010350
Color and Imaging Conference
color imaging conf
2166-9635
Society of Imaging Science and Technology
7003 Kilworth Lane, Springfield, VA 22151, USA