Apparatus and a method for locating edges of a part for acceptance testing of the part. A white light source (12) illuminates the part which is mounted on a support (14) and rotated relative to the light source. Light reflected by the part creates an outline of the part along the edge thereof. The part is viewed by a camera (16) to obtain an image of the part including its edge. A processor (18) analyzes the image to locate the edge of the part in three dimensional space. Analysis of the image includes determining the number of pixels comprising the viewed image, at the edge thereof, as the part is rotated relative to the light source. The part has more than one edge, and each edge is located using the method. The locations of the edges of the part are now used in a co-ordinate system to locate other surface features of the part.