Method and apparatus for determining the position of a body

A system for generating electrical signals representative of the position of a part relative to a reference position and to the rotational orientation of the part relative to that of a similar test part, comprising:

• an image converter operative to receive radiation emanating from the part and the surface supporting the part and to generate electrical signals representative of the radiation values received;
• means for receiving said electrical signals and for generating signals representative of the primary outline of the part relative to the supporting surface;
• means for calculating the centroid of the area bounded by said primary outline and the position of the centroid relative to the reference position;
• means for generating an electrical signal representative of the positions relative to one another of a group of selected points on the outline of the test part;
• means for generating an electrical signal representative of the positions relative to one another of a number of similar points on the outline of the part;
• and means for comparing the first and second electrical signals to determine the rotation of the part relative to the test part.

A system for optically inspecting a sample part and a plurality of similar run parts all supported on the same surface to determine the positions of the sample and run parts and the orientations of the run parts relative to the sample part, comprising:

• optical means for generating signals representative of the outline of the sample and run parts;
• means for operating on the signals representative of the sample part to determine the coordinates of the centroid of the sample part relative to an absolute position, and to generate a sample signature signal containing information representative of the intersection of a circle generated about the centroid of the sample part with the outline of the sample part;
• means for analyzing the signals representative of the outline of a run part to determine the centroid of the run part;
• means for generating a run signature signal representative of the locations of the intersections of a circle generated about the centroid of the run part with the outline of the run part;
• and means for determining the phase shift of the sample signature signal relative to the run signature signal.