Abstract: A master clock oscillator produces a series of control pulses to drive a multiple frequency L.E.D. illuminator and an optically coaxial synchronous detection system in an AC based organic/inorganic, ripe/unripe sorter. Data is collected by subjecting free-falling articles to a repetitious sampling cycle and detecting the reflected pulses. Counters running at differential rates, store binary data relating to the size and ripe/unripe condition of the article. At the end of the sampling period, an accept/reject determination is made, based upon the binary data.

Abstract: An infrared light generator directs a flashing band of light across a conveyor belt carrying randomly spaced materials having differing properties. The frequency of the flashing band sequentially alternates between two infrared frequencies chosen for their peculiar reflectivity characteristics. Infrared light sensitive cells detect energy reflected from the passing materials as they are exposed to the infrared light. Comparator circuitry examines the detected information, determining the size and material nature of the passing pieces. Powered paddles act at the direction of the comparator, physically separating variously sized inorganic from organic materials, or ripe from unripe comestibles, to cite examples.

Abstract: A produce grading system that detects the light reflectances from an object in four color bands. Two bands are in the visible range and two are in the invisible range. By means of comparing various color combinations the system looks for the presence of a desired color, an undesired color, and determines if the object is vegetable or nonvegetable matter.