Method and apparatus for determining the shape and the local surface normals of specular surfaces
Assignees3D-Shape GmbH, the University of Erlangen
InventorsGerd Haeusler, Markus Knauer, Ralf Lampalzer
Life of this patent
Estimating the term…
Abstract
A method teaches how to measure—even strongly curved—specular surfaces with an apparatus that measures a shape as well as local surface normals absolutely. This is achieved by the observation and evaluation of patterns that are reflected at the surface. The reflected patterns are observed from different directions. The evaluation is done by termination of those locations in space, where the surface normals that are observed from different directions, have at least deviations against each other.
Claims29
A method for determining a shape and local surface normals of specular surfaces by observing patterns reflected from a surface, which comprises the steps of:
- recording images of a pattern reflected from the surface from at least two observation directions;
- determining for arbitrary spatial points from at least two of the images, associated potential surface normals with an aid of reflection law for a surface point potentially situated there;
- and
- determining an actual shape and actual local surface normals from a set of spatial points thus treated, at which potential surface normals correspond except for measuring errors.
An apparatus for determining a shape and local surface normals of specular surfaces by observing patterns reflected from a surface, the apparatus comprising:
- means for generating the patterns;
- at least two cameras for recording images of reflected patterns and having optical axes directed from various directions onto a specular surface;
- an electronic computer connected to said cameras and said means, said electronic computer evaluating the images by determining for arbitrary spatial points from at least two of the images associated potential surface normals with an aid of reflection law for a surface point potentially situated there, and determining an actual shape and actual local surface normals from a set of spatial points thus treated, at which potential surface normals, correspond except for measuring errors.
An apparatus for determining a shape and local surface normals of specular surfaces by observing patterns reflected from a surface, the apparatus comprising:
- means for generating patterns;
- at least one camera;
- a device for moving said camera vary an observation direction of said camera so that images of reflected patterns can be recorded from various directions in relation to a specular surface;
- an electronic computer connected to said means and said camera, said electronic computer evaluating the images by determining for arbitrary spatial points from at least two of the images associated potential surface normals with an aid of reflection law for a surface point potentially situated there, and determining an actual shape and actual local surface normals by a set of spatial points thus treated, at which potential surface normals correspond except for measuring errors.
Dependencies are inferred from the claim text.