Abstract: The invention relates to an optical sorting system for a color sorting machine. Product is irradiated with visible, infra-red or ultra-violet light by a transmitter. If there is no product in the ray path of the transmission source, all of the light falls onto a residual light receiver. If product is present, on the other hand, the light is partly or wholly scattered back to one or more product signal receivers.

Abstract: Method and apparatus for controlling a color sorting machine which sorts particulate products based on a color difference between the product and a background. A photoelectric cell receives light reflected from the product and provides an output signal to a microprocessor. The microprocessor uses photoelectric cell output signals of known good products to establish a range of predetermined acceptance values. If the detected signal falls outside the predetermined range, it is determined that the product is defective and an eject signal is provided to an ejector which ejects the bad product from the machine. Outside of the microprocessor, a comparator first compares the photoelectric output signals with the predetermined range of values established by the microprocessor. If the comparator detects a defective product, it provides an eject signal to the microprocessor which then commands the ejector to eject the defective product.