Classifications

• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
  • G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
  • G07D7/12—Visible light, infrared or ultraviolet radiation
  • G07D7/128—Viewing devices
• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
  • G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
  • G07D7/12—Visible light, infrared or ultraviolet radiation
  • G07D7/1205—Testing spectral properties

Definitions

• Apparatus and method for verifying the authenticity of documents for example bank notes or checks.
• the present invention relates to an autonomous and portable device for verifying the authenticity of banknotes, checks or other documents. It also relates to the detection method implemented in the construction of this device and for its use.
• the invention relates more particularly to apparatus and methods using optoelectronic components both at the level of light emission and at the level of reception of the rays reflected by the verified document.
• Document FR-2,759,187 describes a device for detecting counterfeit banknotes, comprising a housing in which are housed optoelectronic components powered by a battery and capable of generating light intended to be reflected by the banknote to control, a photosensitive electronic component making it possible to capture the light reflected by this banknote and to transform it into an electrical quantity, a specific integrated circuit configured to measure this electrical quantity and compare it with a pre-determined "true / false" detection threshold -regulated and to transmit a result, and a signaling means making it possible to warn the user when the result of the analysis is negative and / or positive, the housing comprising a transparent face intended to be applied to the banknote at control; the optoelectronic components consist of blue light-emitting diodes or blue LEDs placed behind and near this transparent face, so as to obscure outside light and to make said device insensitive to any light other than that generated by said blue light-emitting diodes, when its side formed by said transparent face is plated on the bank note to be
• a banknote checking apparatus comprising four LEDs, namely red, green, blue and infrared, used to illuminate a banknote, a light detector for detecting red lights, green, blue or infrared reflected by said bill, A / D means for converting the light detector output signal into a digital signal, means for selectively limiting the output gain of said A / D means in order to obtain a signal output indicative of one of said selected colors, and means for providing said output signal to means for determining the validity of the ticket.
• the purpose of this device is to try to determine with precision the colors of banknotes, by carrying out measurements by reflection on one of the opposite faces of said banknotes, of the three primary colors emitted by LEDs green, red, blue, in order to detect possible variations in nuances differentiating a counterfeit note from a real one.
• modern printing means such as color copiers recently appeared on the market, faithfully reproduce these nuances, so that counterfeit notes which would be manufactured with such materials would in fact be undetectable with the device according to the document WO 97/46 982.
• the process implemented in this device also does not take into account the level of soiling and / or aging of the paper, which leads to analysis results signaling "false" authentic banknotes .
• An object of the invention is to remedy the aforementioned drawbacks and inadequacies of counterfeit banknote detectors operating by analyzing the light reflected by the controlled banknote, lit by one or more LEDs.
• this objective is achieved by a process according to which the document to be checked is successively exposed to several light sources consisting of optoelectronic components and each emitting a different light spectrum, the light reflected by the document, and / or transmitted through it, by means of receiving cells constituted by photosensitive components making it possible to convert the lights received on their sensitive surface, into analog electrical signals transmitted to a processing unit, after shaping and conversion in digital signals, said processing unit integrating an algorithm and being programmed to analyze the digital signals received and to issue a result on the authenticity of the checked document
• the signals from the exposure of the document to one or more light sources are analyzed to determine the level of soiling and / or aging of said document, and the information resulting from this analysis is taken taken into account by the processing algorithm for determining the authenticity of the checked document
• the apparatus according to the invention comprises
• UTANS Digital Signal Processing and Analysis Unit stage
• DSP digital signal processing system
• the main advantage of the method and the device for checking the authenticity of documents such as banknotes is very high reliability, resulting in particular from taking into account signals from several sources of different measurements, in particular signals making it possible to measure the level of soiling and / or aging of said documents.
• Figure 1 is a partial view, schematic of the apparatus according to the invention.
• FIG. 2 is a schematic view illustrating the measurement of the lights reflected by one of the faces of the controlled document, successively lit by several different light sources.
• FIG. 3 is a schematic view showing the measurement of the lights reflected by the two faces of the controlled document and of the lights passing through the latter.
• Figure 4 is a diagram of the light intensity (%) emitted by a 430 nm "super blue” LED.
• Figure 5 is a diagram of the chromatic visibility of the human eye.
• FIG. 6 is a diagram of the light intensity, perceived by the human eye, of a 430 nm "super blue” LED.
• Figure 7 is a schematic view illustrating the mounting of an LED emitting through a light filter.
• Figure 8 is a schematic view showing the mounting of a photosensitive receiver receiving light through a light filter.
• FIG. 9 is a schematic view illustrating another assembly of a photosensitive receiver receiving light through a light filter.
• Figure 10 is a diagram of the RGB components on a yellow gradient.
• Figure 1 1 is a diagram of the RGB components on a gray gradient.
• Figure 12 is a diagram of the light emitted by a 430 nm "super blue” LED through a U-360 light filter.
• FIG. 13 is a diagram of the light perceived by a photosensitive receiver through a U-360 light filter, in the case of a light source constituted by a 430 nm "super blue” LED.
• Figure 14 is a diagram of the "ideal" transfer function of the light filter.
• Figure 15 is a diagram of the possible "ideal" transfer function of the light filter.
• FIG. 16 is a schematic view of an electrical assembly making it possible to regulate the level of light intensity emitted by the LEDs.
• FIG. 17 represents an assembly making it possible to regulate the electric current supplying the LEDs.
• Figure 18 shows the structural flowchart of the device.
• Figures 19A and 19B show a possible algorithm for taking measurements from the device.
• LED means "Light-emitting diode"
• UTANS means digital signal processing and analysis unit
• DSP means "Digital signal processing
• the method and the apparatus according to the invention are intended to make it possible to verify the authenticity of various documents and, more particularly advantageously, the authenticity of banknotes.
• document D is successively exposed to several light sources consisting of optoelectronic components 1A, 1B, ... and each emitting a different light spectrum S1, S2, ... the light reflected LR1, LR2, by said document or transmitted through it, by means of receiving cells constituted by photosensitive components 2A, 2B, making it possible to convert the lights received on their sensitive surface 2a, 2b, into analog electrical signals transmitted to a UTANS processing unit, after shaping and conversion into digital signals, said processing unit integrating an algorithm and being configured and programmed to analyze the digital signals received and to issue a result on the authenticity of the ticket checked.
• the measurement system applying this optical measurement method can be placed, either on one side of the document (FIG. 2) in which case it performs measurements only on this same side, or placed on either side of the document in order to analyze both sides of it ( Figure 3). In the latter case, it is possible, in addition to the analyzes of the various reflected light rays, to carry out analyzes of the light rays transmitted through the document.
• the method and the device according to the invention are based on the use of optoelectronic components both at the level of the emission of light and at the level of the reception thereof.
• the emissions of these light spectra are produced by one or more emitting cells composed of light emitting diodes (LEDs) and light filters.
• LEDs light emitting diodes
• LEDs are:
• LEDs are mounted in different ways:
• the LED (s) 1A emit their light spectrum S1 directly on document D;
• the LED (s) (1 B) emit through a light filter 3 limiting the spectrum of light emitted S2 on document D to wavelengths between 380 nm and 400 nm (or even 410 nm) (purple light ).
• the mounting of this light filter is shown in Figure 7 in which the reference 4 represents an opaque hollow body, while the reference 5 represents the connection wires, while the light emitted is shown in Figure 12.
• This filter light is therefore opaque at wavelengths greater than 400 nm (or even 410 nm) ( Figure 14), possibly this light filter can be transparent at wavelengths greater than 650 nm (see Figure 15).
• the green and / or red LEDs analyzes by reflections and transmissions through the document)
• the LED (s) 1C, 1 D directly emit their light spectra S3, S4 on document D.
• the LED (s) 1 E emit their light spectra directly on document D.
• This cell is made up of photosensitive components (such as, for example: photodiode, phototransistor, photoresistor, etc.) which make it possible to convert the light received on their sensitive surfaces into an analog electrical signal.
• photosensitive components such as, for example: photodiode, phototransistor, photoresistor, etc.
• the receiver 2A directly receives the spectrum of reflected light LR1 from document D.
• the receiver 2B receives the light reflected LR2 by document D through a light filter 6 limiting the spectrum of light received at wavelengths less than 400 nm (or even 410 nm) (FIG. 13).
• This light filter is therefore opaque at wavelengths greater than 400 nm (or even 410 nm) ( Figure 14), possibly this light filter can be transparent at wavelengths greater than 650 nm (see Figure 15).
• These photosensitive components equipped with the light filter can be found directly on the market.
• the LEDs of the emitting cell are powered by a regulation cell 9.
• This cell makes it possible to regulate the level of light intensity emitted by the LEDs in order to obtain reliable measurements and therefore a correct opinion on the authenticity of the document. This regulation can be done:
• the measurement system is not subjected to the same temperature T, it follows that, here too, the light power emitted by the LED varies , distorting the measurements. 2. either by directly regulating the current supplying the LEDs by means of a constant current generator (figure 17).
• This method although a little more complicated and less economical to carry out than the first, has the enormous advantage that the current regardless of the temperature situated approximately between 0 and 50 ° C is only very little dependent on the temperature both the semiconductor and the temperature of the ambient medium.
• the measurements made by light reflections are:
• This measurement is made by lighting a "super blue” LED 1A.
• the light emitted by the "super blue” LED 1A is projected onto the document D. Part of the light is reflected LR1 by the document D towards the photosensitive element 2A.
• the electrical signal produced by the photosensitive element 2A is directly proportional to the soiling or aging of the document.
• any color is the composition of the three additive primary colors which are red, green and blue.
• RGB index red, green, blue.
• white corresponds to an index (255-255-255) and black to an index (0-0-0)
• similarly pure yellow corresponds to an index (255-255-0) and gray to an index (120-120-120).
• This measurement is made by successively lighting a "super blue” LED 1A and a red LED 1 D (and / or green 1C).
• the light S1, S3, S4 emitted respectively by the LEDs 1A, 1 C and 1 D comes to be projected on the document D.
• a part of the light is reflected LR1 by the document D towards the photosensitive element 2A.
• This measurement is made by lighting a "super blue” LED 1A.
• the light S1 emitted by the "super blue” LED 1A is projected onto the document D. Part of the light is reflected LR2 by the document D and passes through a light filter 6 towards the photosensitive element 2B.
• the electrical signal produced by the photosensitive element 2B is directly proportional to the level of violet light reflected by document D.
• Measurement of the level of intensity of violet color light reflected by the document exposed to violet light This measurement is made by switching on a "super blue” LED 1 B. Part of the light emitted by the "super blue” LED 1 B passes through a light filter 3 (emission of light of purple color) and comes project onto document D. Part of the violet light is reflected LR2 by document D and passes through a light filter 6 towards the photosensitive element 2B.
• the electrical signal produced by the photosensitive element 2B is directly proportional to the level of violet light reflected by document D.
• This measurement is made by switching on a "super blue” LED 1 B. Part of the light emitted by the "super blue” LED 1 B passes through a light filter 3 (emission of light of purple color) and comes project onto document D. Part of the light is reflected LR1 by document D towards the photosensitive element 2A.
• the electrical signals produced by the photosensitive elements 2A and 2B make it possible to determine the level of light emitted by the fluorescence of document D, by subtraction: electrical signal produced by 2A - electrical signal produced by 2B.
• This measurement is made by lighting a red LED 1 D and / or infrared 1 E.
• the light S4 and / or S5 emitted respectively by the LED 1 D or 1 E is projected onto document D. Part of the light is reflected LR2 through document D to the photosensitive element 2A.
• This measurement is made by switching on a "super blue” LED 1 B. Part of the light emitted by the "super blue” LED 1 B passes through a light filter 3 (emission of light of purple color) and comes projecting onto document D. Part of the light is transmitted by document D and passes through a light filter 6 to the photosensitive element 2B of the measurement system located on the opposite face.
• a light filter 3 emission of light of purple color
• the electrical signal produced by the photosensitive element 2B is directly proportional to the level of violet light transmitted through the document
• This measurement is made by lighting a "super blue” LED 1A. Part of the light emitted by the "super blue” LED 1A is projected onto document D. Part of the light is transmitted through document D and passes through a light filter 6 to the photosensitive element 2B of the measurement system located on the opposite side.
• the electrical signal produced by the photosensitive element 2B is directly proportional to the level of violet light transmitted through document D. • Measurement of the level of light intensity transmitted through the document exposed to visible light
• This measurement is made by lighting a LED 1A and / or 1 C and / or 1 D of color present in the emitting cell (blue, and / or green, and / or red). Part of the light emitted by LED 1A and / or 1 C and / or 1 D is projected onto document D. Part of the light is transmitted through document D to the non-filtered photosensitive element 2A of the system located on the opposite side.
• the electrical signal produced by the photosensitive element 2A is directly proportional to the level of light transmitted through document D.
• This measurement is made by lighting a red LED 1 D and / or an infrared LED 1 E of the transmitting cell. Part of the rays emitted by the LED 1 D and / or 1 E is projected onto the document D. Part of the rays is transmitted through the document to the unfiltered photosensitive element 2A (if an infrared LED 1 lights up E) or the photosensitive element 2D infrared (if a red LED 1 D and or infrared 1 E of the measurement system on the opposite side are lit).
• the electrical signal produced by the photosensitive element 2A or 2D according to the lit LED is directly proportional to the level of intensity of the infrared rays transmitted through the document.
• the method for checking the authenticity of documents described above can advantageously be implemented in a portable and autonomous electronic device for detecting counterfeit banknotes, of small size supplied by battery or by the sector via a regulating block. external, automatically giving a "True”, “Doubtful” or “False” indication of the controlled bank note.
• This device is in the form of a small housing 10 (FIG. 1) which can easily be held in the hand.
• One of the faces of said device is provided with a transparent window 1 1 and intended to be pressed when using said device, on the white area of the ticket to be checked, placed on an opaque support O.
• This internal structure includes:
• This stage includes the electronic components and circuits known per se and allowing the shaping of the electrical signals coming from the measurement stage.
• the layout allows among other things:
• the controls of the various parameters of the stage of shaping of the measurement signals can be controlled by the UTANS.
• an Analog-Digital Converter stage • an Analog-Digital Converter stage
• This stage comprises the electronic components and circuits known per se and allowing Analog-to-Digital conversion of the analog electrical signals coming from the measurement stage or from the stage for shaping the measurement signals into digital signals transmitted to the stage. utans.
• This stage comprises the various electronic circuits and systems making it possible to control and / or analyze and / or store data coming from the stages:
• UTANS can be made up of:
• DSP digital signal processing system
• This stage includes an assembly allowing the user to communicate with the device by means of keys, accessible on the case of this one.
• This stage comprises the means or means making it possible to give the user data such as the authenticity of the ticket tested, as well as system parameters, by means, inter alia:
• This stage comprises the circuits known per se making it possible to communicate bi-directionally with a computer, for example in order to possibly change program parameters. • a memory stage
• This stage comprises the memory or memories known per se making it possible to store information on volatile and / or non-volatile memories.
• This stage includes an Analog-to-Digital converter enabling UTANS to be informed of the voltage level delivered by the power source, so that the latter stops taking measurements and warns the user of a possible voltage problem d 'food.
• This stage is composed of a voltage regulator and a filtering, making it possible to provide a stable supply to the various circuits composing the internal electronic structure of the device.
• This stage provides a source of energy supplying the device.
• This energy source can consist of:
• the device thus configured may also include circuits
• the battery has too low a voltage level that could affect the proper functioning of the device, a measurement of this voltage level is low. If it has a voltage level below a stored constant, the device will automatically error and indicate to the user the problem, otherwise it follows its normal operating cycle.
• the device can include a sensor taking the ambient temperature and thus after shaping and analog-digital conversion of the signal at the sensor output, the UTANS can adapt the program parameters according to the temperature drift of the electronic components .
• the device measures and analyzes the level of light intensity at the level of the measurement window (all LEDs off). If this light level is greater than a stored constant, the device will automatically go into error and inform the user of the problem, otherwise it follows its normal operating cycle.
• the device again checks the correct plating of the device against the ticket, in order to check whether apparently the series of measurements carried out has been carried out in good conditions.
• the digital signal processing and analysis unit (UTANS) operates in order to indicate by means of the Human-Machine interface an opinion on the authenticity of the bank note tested. This could possibly be repeated as long as the user presses the device against the ticket and presses the button (see measurement algorithm figures 19A and 19B).

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• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Inspection Of Paper Currency And Valuable Securities (AREA)

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• 1999
  • 1999-11-17 FR FR9914463A patent/FR2801125B1/fr not_active Expired - Fee Related
• 2000
  • 2000-11-16 AU AU18675/01A patent/AU1867501A/en not_active Abandoned
  • 2000-11-16 EP EP00981420A patent/EP1232485A1/de not_active Withdrawn
  • 2000-11-16 WO PCT/FR2000/003189 patent/WO2001037226A1/fr not_active Ceased

Non-Patent Citations (1)

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