| 摘要 |
PURPOSE:To allow positive inspection of foreign matter by preventing infrared rays from impinging directly on the light receiving face of a CCD thereby preventing blooming phenomenon at the time of reading out a video signal. CONSTITUTION:A transparent plate is disposed at an inspection position in the way of a belt conveyor and a projector 13 is disposed thereunder while an image sensor 14 is disposed thereabove. The projector 13 is arranged with multiple infrared LEDs 15, 16. When a region where a green laver A is present is detected by irradiating the region with the infrared LED 15, a controller 16 lights the infrared LED 16 through a selecting circuit 21 only in the corresponding region. Consequently, the CCD 18 of the image sensor 14 receives only the attenuated light transmitted through the green laver A and thereby blooming phenomenon is eliminated at the time of reading out the video signal thereof resulting in positive inspection of foreign matter. |
