De La Rue International Limited

Hansjorg Klock

Alexandre Gret

Robert Jones

Michael Stuart Hazell

Peter Dilwyn Evans

Edward John Brindley

Cirillo Ghielmetti

Sushil Bhattacharjee

Joelle Egli

A method of determining the authenticity of a document of value provided with a watermark pattern, the method comprising determining whether the watermark pattern exhibits a discontinuity.

Method and apparatus for determining authenticity

A method is provided of detecting a region of raised material on a document surface. A surface of the document is illuminated with at least one angled radiation beam such that any raised material on the document surface reflects the radiation. The surface containing the raised material is imaged using at least one radiation detector. The image is then processed to detect the existence on the document surface of the raised material. The illuminating step causes a reflection and/or shadow to be generated from at least one edge of the raised material. The processing step detects the location of the material using the said reflection and/or shadow from the at least one edge.

Method and apparatus for raised material detection

In an apparatus for processing banknotes or other sheet-like objects, the banknotes are conveyed along a transport path, thereby passing sensor means. A transmission and a reflection image of the banknote are captured by illuminating the banknotes and measuring the transmittive and reflective light intensity of light with a high resolution. Based on these images, a validation of the banknotes is carried out. After the validation, a double feed detection is performed by evaluating the transmission and the reflection intensities for a predefined set of test spots with a two-dimensional evaluation. If it is decided on double feed, the banknotes are rejected. Otherwise the banknotes are accepted and further processed. Because of the additional dimension in the evaluation compared with known double detection methods, the invention enables a more robust double note detection also in cases with different degrees of soiling of the banknotes.

Optical double feed detection

An optical detection device for validating bank notes has several input apertures, an imagine device (), a diffraction grating () associated with each input aperture () and a detection array (). The diffraction grating () is rotated at angle of e.g.degrees relative to the orientation of the linear detection array (). This arrangement enables the spectra of multiple points to be measured simultaneously. The angle of rotation, the pitch of the apertures () and a pitch of the diffraction grating (15.1, 15.2, 15.3) are selected in such a way that the spectra of said multiple points are contiguously mapped onto the detection array () having a single linear array of color sensitive detection pixels. The axis of the linear array is offset with respect to an optical axis () of the optical detection device.

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Rufenacht, Switzerland

Hansjorg Klock