Abstract: A sorting apparatus for performing an article sort based upon the intensity of light energy reflected from the article at predetermined first and second color wavelengths is characterized by an addressable memory element having a plurality of memory storage locations therein, each memory location being addressable by a different combination of the reflected light intensities at the first and second color wavelengths. Each memory location has stored therein a classification signal representative of the acceptability of an article exhibiting the reflected light intensities at the first and second color wavelengths corresponding to the address of the storage location.

Abstract: Apparatus for sorting articles is characterized by a circuit arrangement responsive to first and second electrical signals representative of the light reflected from the same portion of the article to be sorted as detected against a first and a second background, the first background having a reflectivity characteristic greater than the reflectivity characteristic of the second background, to generate an electrical signal representation of the portion of the viewing zone occupied by the article. This signal is used to scale both the first and second signals to provide an electrical signal representation of the reflectivity of the article at the first and second color wavelengths.