| 摘要 |
PURPOSE:To ensure an accurate checking job despite a position error produced between a camera and a base board by detecting the pad position of solder and the position of a parts independently of each other out of the same picture obtained by the camera. CONSTITUTION:A video signal (a) received from a camera 1 is converted into a gradation signal (b) having the different gradation levels for each picture element by a photoelectric transducer 2 and stored in a picture memory circuit 3. A gradation picture (c) stored in the circuit 3 undergoes deletion of noises through a smoothing circuit 4 and is supplied to a picture differentiating circuit 5 as a smoothed picture (d). The circuit 5 differentiates the vertical or horizontal gradation values of each picture element and obtains a vertical or horizontal gradation changing state to deliver this state as a differentiated picture (e). Both the maximum and minimum points of the picture (e) are detected by a differential peak detecting circuit 6 and the picture (e) is stored in a peak value memory circuit 7 as the differential peak value (f). A differential peak picture (g) stored in the circuit 7 is classified by a pad position detecting circuit 8 and a parts position detecting circuit 9 respectively. Then a relative position error (l1-l2) is obtained between the pad position and the parts position by an error detecting circuit. |
