The electronic processing system

A sophisticated optical sorting machine will track the average colour of the product so that, even though the average product colour may change with time, the machine will continue to remove only the predefined abnormal particles. Optical sorting machines are often provided with a white calibration plate which is either manually or automatically placed in the optical view at user-defined intervals. The machine is then able to correct for any measurement drift that has occurred. 

Once a machine has been set up for a particular product, all the machine settings can be stored in memoiy. This can be repeated for a number of different products and then, at a later time, the machine can be made ready to sort any of these products simply by recalling the appropriate settings from the memory. Alternatively, the settings can be used as a coarse starting point from which to fine tune a machine towards an optimum setting for a particular set of circumstances. Most food plants sort one particular product type. For example a rice mill may sort different varieties of rice, but would not, for example, suddenly switch to coffee. It would be unusual for a food processor to be sorting many different and diverse types of product. 

Advanced sorting machines have a memoiy capability that can be exploited to provide information about the product for the operator. For example, the 

A major part of setting up an optical sorting machine is to achieve the best overall accept/reject ratio for the product being sorted. The operator can do this by using the user interface to adjust the shape and size of the map contour (Figs. 

24 and 6.25) to match as accurately as possible the map contour of the product batch. The sorting sensitivity increases as the machine map contour is decreased in area as it approaches the area of the map contour of the product batch. Product within the area bounded by the threshold levels is accepted and product outside is rejected. These techniques allow an optical sorting machine to remove a far greater range of defects with greater accuracy and without the penalty of 

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Acting upon the suggestions or instructions issued by the electronic processing system in the event of a fault or breakdown. 

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