Abstract: Sorting apparatus, e.g. for root vegetables such as potatoes, comprises a roller table conveyor which has an inspection area onto which a video camera is directed. An operator uses a hand-held probe or wand incorporating a light source and provided with a pressure-sensitive switch in its tip. The switch is actuated by touching a selected article in the inspection area. The position of the wand as indicated by light is given in the video signals fed from the camera to a control circuit to which the switch is also connected. The control circuit also receives speed indicating signals from the conveyor and it provides control signals to operate a finger bank to selectively deflect those articles indicated by a touch of the wand. Provision may be made for a plurality of wands to be used at the same time, each wand having an individually modulated light.

Abstract: In apparatus for sorting potatoes a roller table conveyor conveys potatoes beneath a television camera which produces on a television monitor screen a picture of an inspection area of the roller table. An operator watching the monitor screen selects potatoes to be rejected by pointing a light pen at the monitor screen. The light pen feeds to a microcomputer a signal indicative of the light pen position on the television monitor screen, which corresponds to a transient position of the potato in the inspection area. Sensors deriving signals from sprocket-wheels coupled to the conveyor feed to the microcomputer a signal dependent upon the conveyor speed, and the microcomputer actuates selectively a bank of deflector fingers to deflect reject potatoes. The choice of deflector fingers actuated is determined by one orthogonal co-ordinate of the light pen, and the timing of actuation of the deflector fingers is determined by the other orthogonal co-ordinate of the light pen and the speed of the conveyor.