| 摘要 |
PURPOSE:To identify and discriminate a light part and a dark part of a surface state of an object to be inspected by providing a visual sensor, a differentiation circuit, comparison level setting circuits, comparators, one-shot multivibrator, an AND gate, etc. CONSTITUTION:The visual sensor 1 generates a video signal corresponding to light and darkness of the surface state of the object to be inspected and the differentiation circuit 2 differentiates the signal and converts it into the differential signal. On the other hand, positive and negative comparison level setting circuits 3 and 4 generate the plus and minus comparison levels respectively. Next, positive and negative comparators 5 and 6 compare respective comparison levels with the differential signal as input. Further, the one-shot multivibrator 8 of the positive driving and negative driving is connected with respective output terminals of both comparators 5 and 6 and generates pulses with the preset prescribed width respectively by the output signals. Then, the AND gate 9 inputs the respective output signals of the vibrators 7 and 8 and outputs the signal only in case the dark part is detected, for instance and does not output with respect to the light part.
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