Optical edge-projection method for three-dimensional profilometry.

A novel optical edge-projection method is proposed for surface contouring of an object with low reflectivity. A structured light edge is projected onto a dark surface, and the image is captured by a CCD camera. The object contour is evaluated with an active triangular projection algorithm, and one obtains a whole-field three-dimensional contour of the object by scanning the optical edge over the entire object surface. The proposed method is applied to a black nonreflective object made from woven carbon fiber and is also applied to measure the profile of a small object (a coin). The results show that an accurate profile of the specimen can be obtained.