Patent ID: 9007457
Filing Date: 2015-04-14
Classification: G01B,G06T

Abstract:
1. A method for determining a 3D topography Z(x,y) of a surface of an object, the method comprising: successively illuminating the surface of the object from a plurality of localized axis positions, the object having a specular reflection dominant over a diffuse reflection; acquiring at least one image of the surface of the object at each successive illumination of the surface of the object using a sensor having a sensing axis substantially perpendicular to a general plane of the surface of the object, thereby resulting in a set of radiance images having a same field of view (FOV); for each radiance image of the set, defining a measured radiance at position (x, y) on an image i as a sum of a diffuse reflection term and a specular reflection term dependent on a surface normal vector field N(x, y), a light source direction L solving the set of nonlinear equations for at least the specular reflection term to find the surface normal vector field N(x,y); and integrating the surface normal vector field N(x, y) over the FOV to determine the 3D topography Z(x,y).