Image analysis – Applications – Reading paper currency
Reexamination Certificate
2001-03-28
2002-10-22
Johns, Andrew W. (Department: 2621)
Image analysis
Applications
Reading paper currency
C356S071000
Reexamination Certificate
active
06470093
ABSTRACT:
TECHNICAL FIELD
This invention relates to a system that facilitates authentication of genuine articles and discrimination of genuine articles from counterfeit articles. This invention relates more particularly to first order authentication, detection, discrimination, and recognition of indicia or taggants that become visible when they are excited by sources of invisible radiation, such as ultraviolet (UV) or infrared (IR) light sources. Specifically, the authentication is accomplished by human judgment through visual means by comparing an article with an applicable reference-standard sample-specimen provided with the apparatus and disposed to facilitate comparison.
BACKGROUND ART
The counterfeiting of articles of many kinds has become a serious problem worldwide causing great loss of revenues to legitimate business, individuals, and governments. One of the methods to protect the articles from counterfeiting is incorporation of special markings that are difficult to reproduce but that enable easy detection. Examples are articles that are tagged or marked with identification marks that are printed using normally invisible chemicals, such as UV- or IR-sensitive chemicals. (Throughout this description, the term “taggants” refers to materials or visible or invisible indicia included in or on an article to mark it for authentication. In order to avoid confusion with “pure” ultraviolet light sources that emit only ultraviolet light, those commonly available light sources that emit ultraviolet light and also emit some visible light will be referred to as “black light” sources.)
Counterfeiting, moreover, has produced articles with similar hidden identification marks that are so sophisticated that only high performance scanners and laboratory equipment can distinguish the counterfeit article from the genuine article. At the same time, counterfeiters using primitive methods, apparatus, and processes have produced some less valuable articles, such as food stamps, coupons, toys, etc. that will require first order authentication in the field. Since the articles in question do not command high value, it is often not practical to employ sophisticated apparatus in the first order authentication process. Instead, low-cost and reasonably reliable apparatus is preferred.
Many devices have been developed which can automatically determine authenticity of articles by detecting markings made with substances that are not normally visible in ordinary light, but become detectable by the devices when illuminated with non-visible radiation. U.S. Pat. No. 3,573,472 to Madalo discloses a label verification system in which each label to be verified is imaged onto a matrix of photocells, and an authentic label is imaged onto another matrix of photocells. Symbols on the labels preferably contain photoluminescent substances, and the matrix of photocells is provided with suitable filters, so that when the labels are illuminated with ultraviolet light, photocell responses are at a much higher degree of contrast. U.S. Pat. No. 4,146,792 to Stenzel et al. discloses paper secured against forgery and a device for checking the authenticity of such papers. The paper carries materials that fluoresce in the visible, ultraviolet, or infrared spectral range in characteristic emission spectra. The device includes a light source for exciting fluorescent substances, a condenser lens concentrating the light emitted by the paper, a narrow band interference filter, a focusing lens, and a series of photocells arranged in the focal plane of the focusing lens. The outputs of the photocells are fed to a preamplifier and then to a comparator, and outputs of photocells are compared to establish the authenticity of the paper. U.S. Pat. No. 4,277,774 to Fujii et al. discloses a currency discriminating apparatus that utilizes the presence of a light-emitting substance in a printed zone of the currency when irradiated with ultraviolet rays. The apparatus comprises an ultraviolet ray-emitting member, a photoelectric converter element, and a discriminating circuit for checking pattern signals. U.S. Pat. No. 4,558,224 to Gober discloses a counterfeit paper currency bill warning device that utilizes the characteristic fluorescence of genuine paper currency. In Gober's device, an ultraviolet lamp illuminates the paper currency of unknown origin, and a sensor circuit responds to fluorescent radiation from the currency to give a signal to an indicator which displays an indication of the fluorescence of the unknown paper currency relative to the fluorescence of genuine paper currency. The sensor is a photoresistor and the indicator is a variable intensity light or a digital display.
U.S. Pat. Nos. 4,451,521 and 4,598,205 to Kaule et al. disclose security paper with authenticity features in the form of substances luminescing only in the invisible region of the optical spectrum. A corresponding test apparatus makes it possible to check the authenticity of the security paper in the presence of customers but unnoticed by them. The invisibility of the test signal and the authenticity signal are taken advantage of, and the test device is hidden behind a plate non-transmissive for visible light, which however is transmissive for the test signal and for the authenticity signal. U.S. Pat. No. 4,833,311 to Jalon discloses a security marking procedure, an apparatus to sense a security marking, and fiduciary documents provided with security markings utilizing rare-earth chelates consisting of at least two rare earths. The fluorescent wavelengths of the rare-earth chelates vary as functions of temperature.
U.S. Pat. No. 4,889,367 to Miller discloses a multi-readable information system which includes information in a machine-readable bar code and a different type of information that occupies the same field area of the substrate material, such as information in humanreadable symbology that is printed in at least a portion of the area occupied by the bar code. The bar code is printed in a first ink that can be read utilizing energy of a first wavelength and the human-readable symbols are printed in a second ink that can be read under illumination by a humanly visible wavelength. U.S. Pat. No. 5,414,258 to Liang discloses apparatus and methods for calibration of fluorescence detectors; the apparatus incorporates standard target elements comprising predetermined fluorescent substances with known emission spectra and either non-fluorescent substances or fluorescent substances with other known emission spectra.
Automated authentication systems for articles tagged with UV sensitive chemicals are well established, for example, the Angstrom Technologies Omni series UV scanners and systems. Similar systems are described in U.S. Pat. No. 4,642,526 to Hopkins, in U.S. Pat. Nos. 5,418,855, 5,548,106, 5,574,790 and 5,666,417 to Liang et al., and in U.S. Pat. No. 5,719,948 to Liang. These authentication systems prove to be accurate and fast in authentication without needing any human subjective judgment. They are commonly employed to differentiate valuable genuine articles from the counterfeit articles. However, they are also relatively expensive and sometimes cannot be justified for applications where the value of the articles in question is very low. Furthermore, in situations where not all articles have been tagged with the specialty chemicals, such as older passports, bank notes, and some credit cards, a fully automated system could give false readings if the articles are scanned automatically without human intervention. Similarly, a universal automated scanner for all credit cards or bank notes will be a challenging task because various credit cards and bank notes have different markings, with different taggants, and at different locations on the cards or notes.
PCT International Publication WO 97/06502 “Optical Image Authenticator” by Atherton et al. describes an authentication system in which a light intensity pixel array is detected and compared with a reference pixel array to determine if each pixel is either good or bad. Authentication is done on the basis of
Angstrom Technologies, Inc.
Johns Andrew W.
Touw Theodore R.
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