| 摘要 |
<p>Disclosed is a document or article carrying information for the audible authentication of said document or article wherein the information is present in or on said document or article in the form of a frequency versus time spectral density function (spectrogram) the spectrogram being embodied using document security means. Disclosed are further a method for producing said document or article; a reader device for displaying audible authentication information from said document or article a method for authenticating said document or article and the use of a spectrogram for document authentication purposes.</p> |
