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...http://www.google.de/patents/US5000569?utm_source=gb-gplus-sharePatent US5000569 - Light reflection defect detection apparatus and method using pulsed light-emitting semiconductor devices of different wavelengths
