| 摘要 |
PURPOSE:To enable a required part to be detected to be surely recognized by arranging the part located on a plane so that the projected images of the corners of the part are formed on the same plane and calculating the shadow information of the images by combining a plurality of pieces of the information. CONSTITUTION:The irradiation of light on a circuit part 3a from an oblique direction (4) forms shadows 20a-20d. Accordingly, an image pickup camera picks up and stores (10a-10d) the shadows 20a-20d, an electrode 30, a white marking 32 and the like. A density converting circuit is set so that the electrode 30 and the marking 32 are clipped to prescribed values. Then, a difference between the image signals A and B of memories 10a and 10b, respectively, is calculated (11a) for every signal of the same coordinates and difference signals E are outputted to an adding circuit 11c. Difference signals F between the image signals C and D of memories 10c and 10d, respectively, are outputted to the circuit 11c. Signals G are extracted as a region 36 with a zero density in the circuit 11c wherein the electrode 30 and the marking 32 are separated from each other. The signals G are binary-coded (12) to remove the unevenness of illumination, binary-coded signals H are inputted to an arithmetic circuit 16 and the center of gravity of the electrode 30 is arithmetically processed (16) whereby the presence or absence, positional deviation and the like of the part 3a can be recognized with a high accuracy.
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