Foreign object separation apparatus

A foreign object separation apparatus comprising a feed conveyor (8) for delivering material to be processed to an inspection region where the material descends, means (10, 11) for illuminating the material in the inspection region, a plurality of fluid blast nozzles (22), a plurality of solenoid controlled valves (21) connected respectively to said nozzles, a camera (12) for scanning the material descending in the inspection region, said camera having a view which is separated electronically into a plurality of main zones and a plurality of overlap zones which are smaller than said main zones, each of said overlap zones covering a portion of two adjacent of said main zones, each of said main zones corresponding to separate solenoid controlled valves, a background compensation and video comparator (23) connected to said camera to receive pixel data therefrom, said comparator developing a reject data signal to indicate the presence of foreign material within one or more of said main and overlap zones, a reject position decoder (18) for receiving said reject data signal from the comparator, a programmable zone boundary decoder (19), the outputs of said reject position decoder (18) and said boundary decoder (19) being synchronized by clock signals outputed by said camera, and a zone decoder logic circuit (20) connected to the outputs of said reject position decoder (18) and said boundary decoder to produce output signals which actuate said solenoid controlled valves, said zone decoder logic circuit (20) being programmable so that when a reject data signal from said comparator (23) which represents that foreign material is wholly within a main zone but outside an overlap zone is decoded in the zone decoder logic circuit, the corresponding solenoid controlled valve for such main zone only will be actuated, whereas when a reject data signal from said comparator which represents that foreign material is wholly or partly within a main zone, and also wholly or partly within an overlap zone is decoded in the zone decoder logic, the solenoid controlled valves (21) controlling the nozzles (22) corresponding to the solenoid controlled valve for such main zone and the adjacent main zone will be actuated.