Identification and sorting system - has obliquely aligned light sensor w.r.t. conveyor having segment partially obscured by bottle and framed by two non obscured segments

摘要

The object (12) travels along a conveyor belt (10) through an oblique beam of light from an extended source (e.g. fluorescent tube) (20) to a receiver (e.g. linear array of photodiodes) (22). An optical system forms on the receiver surface an image of those parts of the source (20) which are not obscured by the object (12). The distance between the object and receiver is controlled to within 1 cm so that for a given shape of object the position of the image edge w.r.t. a given mean does not vary by more than one photodiode of the array. The variations in length of the occulted and unobscured segments are processed to obtain a relationship characteristic of the shape, whose parameters are compared with those of typical objects for classification purposes. The object can be identified regardless of its speed on the conveyor belt.