Estimating the location of illuminants in realist master paintings Computer image analysis addresses a debate in art history of

In cast-shadow analysis one merely draws a line between each occluder and its associated shadow cast onto a different surface, possibly with wedges indicating precision. In some cases one merely estimates the direction consistent with the evidence and knowledge of basic physics. These lines should converge onto the location of a single source. Cast-shadow analysis The general problem of inferring the direction of illumination from shading is difficult because it requires the estimation of the normal to a surface. Nilius and Eklundh [2] realized that the normal is known perfectly along an occluding boundary: the normal is perpendicular to our line of sight (i.e., is in the plane of the image) and is perpendicular to the contour. The algorithm assumes the surface is Lambertian of uniform albedo and takes as input the lightness at each of several (e.g., four) segments along an occluding contour. The algorithm computes a least-squares estimate of the direction most compatible with all the...

• Type: Conference
• Year: 2006
• Where: ICPR
• Keywords: Computer Vision, ICPR 2006, Occluding-contour Algorithm, Single Direction Estimate, Wedges Indicating Precision