APPARATUS FOR THE REGISTRATION OF THREE-DIMENSIONAL SHAPES

An apparatus for identifying surfaces, comprising a point digitizing apparatus for obtaining data points of a surface to be located and an apparatus, such as a memory device, for storing a mathematical model of a model surface. A microprocessor control unit registers the mathematical model and the obtained data points, wherein the microprocessor control unit accomplishes the registration by (i) determining a data point set comprising various points from the obtained data points, (ii) finding a set of closest points comprising, for each point of the data point set, a closest point on the first mathematical model, (iii) registering the data point set to the set of closest points to obtain a registered point set, (iv) computing a mean square distance of points of the registered point set to the closest point set, (v) comparing the mean square distance to a predetermined threshold and (vi) if the mean square distance is above a threshold, (vi.i) redefining the data point set as the registered point set and (vi.ii) repeating parts (ii), (iii), (iv) and (v). Resultant from the registration, the control unit provides an output signal that can be used to indicate the surface position, quality and/or identification.