Patent ID: 8400509

Claim:
A value document authentication apparatus for authenticating a value document having a uniform distribution of at least one phosphor capable of emitting infrared radiation with at least one distinct infrared wavelength, and one or more pre-selected patterns capable of affecting intensity of the infrared radiation, the document authentication apparatus comprising: a. at least one phosphor exciting light source having sufficient energy to excite emission from the at least one phosphor; b. at least one sensor arranged to detect, with spectral resolution, infrared radiation emitted from the value document within a pre-selected track on the value document excited by the phosphor exciting light source; wherein the pre-selected track comprises at least one pre-selected pattern capable of affecting intensity of the infrared radiation, wherein the sensor detects the intensity of the infrared radiation of at least one wavelength emitted from at least one location within a series of pre-selected partially overlapping regions of the pre-selected track, which represents an intensity profile, and produces intensity data when the value document is exposed to the sensor at a pre-selected uniform velocity, and c. at least one processing unit comprising: (i) a normalized true intensity data storing unit that stores normalized true intensity data obtained from detecting true intensity data at the pre-selected locations and normalizing the true intensity data of a pre-selected number of authentic reference value documents, wherein the normalized true intensity data is obtained by removing areas of high variation from the detected true intensity data and by setting the area under the remaining intensity profile to a value of one hundred percent; (ii) a normalized test intensity data storing unit that stores normalized test intensity data obtained from detecting test intensity data of a test value document at the same pre-selected locations as the authentic reference value documents and normalizing the test intensity data by removing areas of high variation from the detected test intensity data and by setting the area under the remaining intensity profile to a value of one hundred percent; and (iii) a comparing unit that compares the normalized true intensity data to the normalized test intensity data and authenticates or rejects the test value document.