| 摘要 |
A light-reflection defect detection apparatus and method for sensing the presence of food products or other articles and detecting defects therein is described using pulsed light-emitting semiconductor devices, such as light-emitting diodes (LEDs). The LEDs emit at least three different wavelengths of light including two of visible light (i.e., red and green light) and one of infrared light. Viewers each including a photosensor, such as a photoelectric detector, are employed to sense the light reflected from the article and to produce sensor output signals which are sampled and stored before being transmitted to a digital computer for signal processing. The groups of LEDs are pulsed ON and OFF by a capacitor discharge pulse generator circuit which causes a substantially constant current to flow through the LEDs so that they emit light of uniform intensity. The defect detection apparatus and method is especially useful in detecting defects in elongated food products such as French-fry potato strips.
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