Identification of products in supermarket - using label code that depends upon acoustic resonance characteristic of metal label

摘要

The product coding system is based upon a label with a pattern formed in a thin metal strip. The principle of operation is based upon acoustic excitation of the strip which is dependent upon the pattern. Typically the pattern is formed by a series of rectangular slots. The label (12) is fixed to the product (11) and is set in resonance by the output of an acoustic generator (14). The resonating field is detected by a microphone (16). Both generator and microphone can be located well clear of the product. ADVANTAGE - Label reading does not require close positioning of sensor.