Method and apparatus for determining the displacement of a rectangular object with respect to a reference position

Abstract

A method for determining the displacement in six degrees of freedom of a rectangular planar surface with respect to a reference position includes providing a reference image having projections of a defined lighting pattern having at least six points on a reference rectangular planar surface in the reference position, the six points including first, second and third points on the reference surface, fourth and fifth points at the intersections of a first edge of the reference surface, and, respectively, first and second parallel lines in the plane of the reference surface and perpendicular to the first edge, and a sixth point at the intersection of a second edge of the reference surface and a third line in the plane of the reference surface and perpendicular to the second edge, the first edge being perpendicular to the second edge, and the first and second points being in known relationship with the first, second and third lines. The method further includes the step of obtaining a real image including the projection of the lighting pattern on the surface, and determining the displacement of the surface with respect to the reference position from the positions of the six points in the reference image and the real image.

Dependencies are inferred from the claim text.