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Titolo: On the relationship between radiance and irradiance: Determining the illumination from images of a convex Lambertian object
Autore: Ramamoorthi, R; Hanrahan, P;
 Indirizzi:
 Stanford Univ, Dept Comp Sci, Stanford, CA 94305 USA Stanford Univ Stanford CA USA 94305 Dept Comp Sci, Stanford, CA 94305 USA
 Titolo Testata:
 JOURNAL OF THE OPTICAL SOCIETY OF AMERICA AOPTICS IMAGE SCIENCE AND VISION
fascicolo: 10,
volume: 18,
anno: 2001,
pagine: 2448  2459
 SICI:
 10847529(200110)18:10<2448:OTRBRA>2.0.ZU;2#
 Fonte:
 ISI
 Lingua:
 ENG
 Tipo documento:
 Article
 Natura:
 Periodico
 Settore Disciplinare:
 Physical, Chemical & Earth Sciences
 Engineering, Computing & Technology
 Citazioni:
 25
 Recensione:
 Indirizzi per estratti:
 Indirizzo: Ramamoorthi, R Stanford Univ, Dept Comp Sci, Gates Wing 3B386, Stanford, CA 94305 USA Stanford Univ Gates Wing 3B386 Stanford CA USA 94305 5 USA



 Citazione:
 R. Ramamoorthi e P. Hanrahan, "On the relationship between radiance and irradiance: Determining the illumination from images of a convex Lambertian object", J OPT SOC A, 18(10), 2001, pp. 24482459
Abstract
We present a theoretical analysis of the relationship between incoming radiance and irradiance. Specifically, we address the question of whether it is possible to compute the incident radiance from knowledge of the irradiance at all surface orientations This is a fundamental question in computer vision and inverse radiative transfer. We show that the irradiance can be viewed as a simple convolution of the incident illumination, i.e., radiance and a clamped cosine transfer function. Estimating the radiance can then be seen as a deconvolution operation. We derive a simple closedform formula for the irradiance in terms of spherical harmonic coefficients of the incident illumination and demonstrate. that the oddorder modes of the lighting with order greater than 1 are completely annihilated. Therefore. these components cannot be estimated from the irradiance, contradicting a theorem that is due to Preisendorfer. A practical realization of the radiancefromirradiance problem is the estimation of the lighting,from, images of a homogeneous convex curved Lambertian surface of known geometry under distant illumination, since a Lambertian object reflects light equally in all directions proportional to the irradiance. We briefly discuss practical and physical considerations and describe a simple experimental test to verify our theoretical results. (C) 2001 Optical Society of America.
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/09/20 alle ore 06:44:44