Method and apparatus for obtaining and analyzing an image of a elongate slot

A method for inspecting a position of an elongate slot in a piece part restrained on a supporting surface of a turn table of an elongate slot punching apparatus, comprising the steps of:

• taking a picture of a piece part and storing an image of an actual elongate slot in a processing means;
• determining first (Y.sub.1) and second (Y.sub.2) extreme coordinate end positions of the image of the actual elongate slot in a direction spaced normally from the supporting surface of the turn table supporting the piece part;
• calculating an actual center coordinate position (7.sub.a) of the image of the actual elongate slot in a direction normal to said surface based on said first (Y.sub.1) and second (Y.sub.2) extreme coordinate end positions of the actual elongate slot;
• determining third (X.sub.1) and fourth (X.sub.2) extreme end positions of the image of the actual elongate slot in a direction normal relative to an axis of rotation of the supporting surface;
• calculating an actual center coordinate position (X.sub.a) of the image of the actual elongate slot in a direction normal relative to said axis based on said third (X.sub.1) and fourth (X.sub.s) extreme coordinate end positions;
• determining first and second difference center coordinate values (Y.sub.d,X.sub.d) between the actual (Y.sub.a,X.sub.a) and predetermined target (Y.sub.t,X.sub.t) center coordinate values;
• and
• recording the first and second difference coordinate values (Y.sub.d,X.sub.d);
• fitting a line tangent to an image of said actual elongate slot at a predetermined portion along an edge of the actual elongate slot;
• measuring an actual angle (.alpha.) of the tangent line relative to the supporting surface;
• determining a difference angle value (.theta.) between the actual angle (.alpha.) of the tangent line and a predetermined target angle (.beta.);
• and
• recording the difference angle value (.theta.).

An inspection device for automatically determining an accuracy of an irregular shaped elongate slot disposed through an annular ring prior to removal of the annular ring from a punching apparatus, comprising:

• a turntable having a supporting surface and supporting said annular ring having said irregular shaped elongate slot disposed therethrough, said annular ring being positioned on the supporting surface at a preselected location relative to an axis of rotation of the supporting surface;
• illumination means for directing back lighting towards the annular ring and illuminating the irregular shaped elongate slot;
• camera means for taking a picture of the illuminated irregular shaped elongate slot and delivering an image of said irregular shaped elongate slot, said annular ring being located between the camera means and the illumination means;
• first means for receiving the image of said irregular shaped elongate slot, determining a first actual center coordinate value (Y.sub.a) of said irregular shaped elongate slot in a direction normal to said table surface based on said image, determining a second actual center coordinate value (X.sub.a) of the irregular shaped elongate slot in a direction normal to said axis based on said image, determining an actual angle value (.alpha.) of the irregular shaped elongate slot relative to the turn table surface based on said image, and storing said first and second actual center coordinate (Y.sub.a,X.sub.a) and angle values (.alpha.).