Patent ID: 8917901

Claim:
A method of determining the surface profile of a diffusely illuminated object, the method comprising: obtaining or determining three inputs that either are, or represent, three images of the object being at planes which are spaced from one another and outside the depth of field of an optical system capable of imaging the objects; obtaining or determining one further input that is, or represents, a light distribution image of the object within the depth of field of the optical system to provide a substantially focused image of the object; the three inputs that are, or represent, three images outside the depth of field providing height information of the surface of the object from a predetermined datum and the further input that is, or represents, the light distribution image from within the depth of field providing the light distribution from the surface of the object but no depth information; and processing the four inputs to determine a height distribution from the predetermined datum and therefore the surface profile of the object.