Shape from motion for unknown, arbitrary lighting and reflectance

摘要

Systems and methods are disclosed for determining three dimensional (3D) shape by capturing with a camera a plurality of images of an object in differential motion; derive a general relation that relates spatial and temporal image derivatives to BRDF derivatives; exploiting rank deficiency to eliminate BRDF terms and recover depth or normal for directional lighting; and using depth-normal-BRDF relation to recover depth or normal for unknown arbitrary lightings.

主权项

1. A method for determining three dimensional (3D) shape, comprising:
capturing with a camera a plurality of images of an object in motion;deriving a general relation that relates spatial and temporal image derivatives to bidirectional reflectance distribution function (BRDF) derivatives;with isotropic BRDF ρ, determining image intensity I of a 3D point x, imaged at pixel u, as
I(u,t)=σ(x)ρ(n,x),where σ is the albedo and n is the surface normal at the point and cosine fall-off is absorbed within ρ and relating I to depth and gradient;exploiting rank deficiency to eliminate BRDF terms and recover depth or normal for directional lighting; and
using depth-normal-BRDF relation to recover depth or normal for unknown arbitrary lightings; and determining the 3D shape from the motion.