摘要 |
A sheet element, such as a banknote, has an incorporated authenticating device comprising a film having at least one edge which is provided with a non-rectilinear portion or portions shaped to provide coded information relating to the sheet element. The shape and proportions of said at least one edge of the shaped non-rectilinear portion or portions of said film are sensed to generate a signal dependant upon the shape and proportions of the edge of the film so as to derive the coded information. |