An image processing method and apparatus wherein document information is separated by using an optical device into two colors that are complementary to each other, converted photo-electrically and processed by using a photo-electric conversion device, and extracted on the basis of the result of processing...http://www.google.fr/patents/US4825246?utm_source=gb-gplus-shareBrevet US4825246 - Image processing method and image forming apparatus
Image processing method and image forming apparatus
