Patent ID: 8224066

Claim:
A method for high-resolution deflectometric measurement of a local slope and a three-dimensional shape of an object, the method which comprises: providing a microscopic imaging system having a numerical aperture, a focus plane, and a receiving unit; an illuminating system having a grating generator configured to generate a grating; and a control and evaluating unit; placing an object in an object space of the imaging system; with the illuminating system, generating a series of grating images in the object space at a distance d from a focus plane of the microscopic imaging system; controlling the illuminating system to image the grating images into the object space with an adjustable period p; choosing the period p in dependence on a distance d so large that a contrast of the observed modulated images is sufficient for low-noise evaluation; with the imaging system, imaging a modulated image onto a receiver unit, the modulated image being formed of the object and the grating image reflected at the object or transmitted through the object; and determining local slope components of the object surface from the series of modulated images with the evaluating unit.