| 摘要 |
There is described a method of producing a document coded with machine-readable information, said document having an information carrier with a multiplicity of storage positions, wherein selected storage positions are occupied by respective machine-readable optical markings, which markings cause a predetermined modification of incident light; the geometrical position of the markings on the information carrier represents coded information. In the method disclosed, such an optical marking is introduced into each storage position, and subsequently, selected optical markings are cancelled or altered. Also described are documents coded by means of the disclosed method, as well as a device for cancelling or altering the optical markings. |
