The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 29, 2008
Filed:
Feb. 14, 2005
Baback Moghaddam, Cambridge, MA (US);
Baback Moghaddam, Cambridge, MA (US);
Mitsubishi Electric Research Laboratories, Inc., Cambridge, MA (US);
Abstract
A method determines a direction of a principal light source in an image. An input image I is acquired of an object illuminated by a principal light source from an unknown direction. The input image includes an array of pixels, and each pixel has an intensity I(x, y). An intensity vector {right arrow over (I)} is constructed from the intensities of the input image. An albedo map ρ is defined for the object. An albedo vector {right arrow over (ρ)} is constructed from the albedo map. A shape matrix N is generated for the object. The albedo vector {right arrow over (ρ)} is multiplied by the shape matrix N to obtain a shape-albedo matrix A. Then, a direction s* to the principal light source is estimated from the intensity vector {right arrow over (I)}, the albedo vector {right arrow over (ρ)} and the shape-albedo matrix A according to an optimization