(19)
(11) EP 0 744 716 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
18.12.1996 Bulletin 1996/51

(43) Date of publication A2:
27.11.1996 Bulletin 1996/48

(21) Application number: 96303493.9

(22) Date of filing: 16.05.1996
(51) International Patent Classification (IPC)6: G07D 7/00
(84) Designated Contracting States:
DE ES FR GB IT

(30) Priority: 25.05.1995 GB 9510678

(71) Applicant: NCR INTERNATIONAL INC.
Dayton, Ohio 45479 (US)

(72) Inventor:
  • Cumming, Heather L.
    Dundee DD2 2NH, Scotland (GB)

(74) Representative: Robinson, Robert George 
International Patent Department NCR Limited 915 High Road North Finchley
London N12 8QJ
London N12 8QJ (GB)

   


(54) Method and apparatus for authenticating documents


(57) In a method and apparatus for authenticating documents, at least one small area (22) on a document (12) being tested is sensed by a spectroscope (26), and the light intensity at a plurality (e.g. 50) of spectral points is measured by a photodiode array (30). The resulting signals are digitized in an analog-to-digital converter (38) and the resulting data is stored. This data is then analyzed by discriminant analysis, whereby the intensity values treated as components of a vector are multiplied by one or more sets of weighting coefficients (discriminant functions) to provide a set of discriminant function values. A distance measurement between this set of values and the centroid of a corresponding set of values for genuine documents is compared with a threshold value to determine the authenticity of the document (12).






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