Abstract: The procedure includes observation of each grain by optic-electronic devices and consists of an initial stage during which several values, representing color signals, are extracted and read and are then processed by a computer to reduce all the signals to two numbers only, defining a pair of coordinates on a plane where the colorimetric characteristics of the grains are represented, and of a second stage in which each grain is automatically classified within an electronic grid, related to the above plane, wherein an operator has already assigned the squares for classes of unacceptable grains. The machine includes an analog-to-digital converter able to convert the analog signals received from the observation devices into binary form, two adapter circuits, a computer and a memory for controlling, sampling and analog-numerical conversion of the color signals, also for storing all samples obtained, as well as for executing the above first and second stages of the procedure.

Abstract: A sorting machine is disclosed for sorting objects by examining light from the objects in at least two different parts of the spectrum. The objects to be sorted are fed to a viewing zone where they are illuminated in at least two different parts of the spectrum. The objects passing through the viewing zone are viewed against at least one background which is illuminated by at least first and second lighting units which are separate from the lighting employed to illuminate the viewing zone, the first and second lighting units being respectively arranged to cause the respective background to emit light in the at least two different parts of the spectrum. A discriminator is employed for determining whether objects which have been so viewed are desired, and there is an object separator controlled by the discriminator, for effecting relative separation between desired and undesired objects.

Abstract: A sorting machine comprising a chute for moving a plurality of objects sequentially past a plurality of viewing zones which are spaced apart in the direction of movement of the objects so that the moving objects pass to an object separation zone in which relative separation is effected between desired and undesired objects. Light sources are on opposite sides of the moving object for directing beams of light to the viewing zones. Viewing devices view the objects passing through the viewing zones from opposite sides, respectively, of the moving objects. A discriminator, controlled by the output from the viewing devices, determines whether objects which have been so viewed are desired or undesired. An object separator controlled by the discriminator effects relative separation at the object separation zone between the desired and undesired objects.

Abstract: A sorting machine for sorting ground nuts affected by a mould which produces aflatoxin comprises detectors for detecting infra-red (or red) and green light respectively reflected from a ground nut being viewed. The infra-red detector produces a first signal indicative of the amount of mould carried by the ground nut. The green detector produces a signal indicative of the extent to which the ground nut is mechanically damaged, and also produces a gating signal. A comparison signal is derived from these first and second signals and is passed by way of a gate and a level detector to an ejector. The gating signal controls the operation of the gate in dependence upon the extent to which the ground nut being viewed is mechanically damaged, so that the ejector is actuated by comparison signals of a predetermined level only when the extent to which the ground nut is mechanically damaged does not exceed a predetermined value.