Abstract: The system comprises a high resolution camera (1) mounted above a conveyor plane (4) along which objects are displaced, thereby enabling the top face of each object to be observed. The camera (1) is fitted with an objective lens system (5) having a motor-driven focusing system that operates in association with a pickup (8) that produces a signal (S) representative of the vertical profile of the top face of each object relative to the conveyor plane. The profile signal serves to produce positioning references (C) for the focusing mechanism in order to take account of variations in the height of the top face of each object while that object is moving beneath the objective lens system of the camera. Such an image acquisition system is employed to read addresses automatically from postal packets for the purpose of performing automatic sorting.

Abstract: The apparatus of the invention for discriminating mail in a paper envelope from mail in a plastics envelope makes use of a pneumatic technique. In particular, the apparatus comprises a pneumatic system suitable for deforming the envelope to be inspected by applying suction and for measuring variation in pressure associated with said deformation, whereby the inspected envelope is detected as being a paper envelope or as being a plastics envelope. This pneumatic detector may be associated with a detector operating by means of an optical effect for the purpose of controlling a labelling device in equipment for processing flat articles.

Abstract: The device comprises a conveyor (1) for displacing the envelope, in a displacement direction (D), along a path including a bend, and a member (12) disposed on the outside of the bend and downstream therefrom in said displacement direction, said member (12) cooperating with the conveyor (1) to cause the envelope to curve around the bend, and being movably mounted relative to the conveyor, so as to move a certain distance away from the conveyor depending on the thickness of the envelope and on its stiffness. A sensor (30) is provided to detect said certain distance minus the thickness of the envelope exceeding a predetermined threshold, thereby detecting that a hard object is present inside the envelope. The present invention applies to the processing of mail items.