Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
  • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
  • G06V40/12—Fingerprints or palmprints
  • G06V40/1335—Combining adjacent partial images (e.g. slices) to create a composite input or reference pattern; Tracking a sweeping finger movement
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F18/00—Pattern recognition
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
  • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
  • G06V40/12—Fingerprints or palmprints
  • G06V40/1382—Detecting the live character of the finger, i.e. distinguishing from a fake or cadaver finger
  • G06V40/1394—Detecting the live character of the finger, i.e. distinguishing from a fake or cadaver finger using acquisition arrangements

Definitions

• the invention relates to devices for the biometric recognition of persons, intended for applications where a high level of security is required against the risks of fraud, and where the presence of a determined natural person, and the certain identification of this person, is required to limit the risks.
• the device according to the invention uses a fingerprint image sensor.
• a fingerprint image sensor is produced from an integrated circuit, in principle based on silicon, comprising in particular a matrix of individual sensitive elements making it possible to establish a representation of the image of the fingerprint.
• a finger placed directly or indirectly on the surface of the matrix.
• the detection of the imprint is generally optical or capacitive or thermal or piezoelectric and the sensitive elements of the sensor are then respectively sensitive to light or to capacitive proximity or to heat or pressure.
• Some sensors operate in the presence of a finger statically placed on the surface of a sensor whose active detection matrix is rectangular or square; in this case, the surface of the sensor has an overall size corresponding to the footprint surface to be detected; other sensors operate by sliding the finger on a sensor whose detection matrix, with a surface much smaller than the imprint to be detected, is an elongated strip of a few rows of point detectors (or even a single row).
• Known fingerprint capture techniques do not make it possible to detect whether the finger is alive: one can deceive the sensor by using a molded false finger, but one can also use a thin layer of plastic material on which is molded a copy of the imprint, this layer being glued on a real finger; one can also deceive the sensor, and this fraud is practically impossible to detect, with a cut finger, physiology extremely close to a finger normally connected to its original body.
• a detection technique using two electrodes and measuring the conductivity or impedance of the finger has already been proposed, but is easily deceived by wetting a false plastic finger with saliva, or by using a conductive plastic, or even simply aluminum foil pressed against the false finger.
• This technique cannot be very precise because the conditions of use can be very varied, and the finger for the same individual can have a very dry or very wet surface, which requires having a very wide acceptance area for the measured impedance; a large acceptance area obviously facilitates fraud.
• the pulse measurement techniques are incompatible with the scanning fingerprint capture technique as described in the patent FR 2 749 955, because the scanning time is of the order of half a second, largely less than a heartbeat.
• a technique for spectral recognition of the skin, and more precisely of the dermis is proposed for the identification of people. The precision of this technique is not yet proven, and it will probably not be greater than what fingerprint recognition allows.
• LEDs light-emitting diodes
• analyzing the light transmitted by the skin at various distances using a few photodiodes to measure the characteristics of this light: the greater the distance between the Light emitter and sensor is important, and the more you get the characteristics of the dermis in depth.
• certain frequency bands towards infrared
• the number of photodiodes and light-emitting diodes will be limited by the fact that they must be assembled individually, and therefore the associated cost increases very quickly.
• the present invention proposes to use, for the recognition of persons, a fingerprint image sensor (in principle on silicon chip), optical or not, associated with spectral recognition of the skin using fewer emitting elements. of light (LED light-emitting diodes in general) only if spectral recognition had been used alone.
• the invention therefore provides a person recognition device comprising, on the same base, both a fingerprint image sensor and a spectral transmission information sensor relating to the skin of the finger whose imprint is detected by the image sensor.
• light emitting diodes will preferably be used, but not necessarily, and a specific image will be obtained from each light emitting diode transmitted by the finger from these light emitting diodes.
• Detection photodiodes will preferably be arranged in an array to provide a set of spectral information comparable to a specific spectral "fingerprint" of the individual.
• This capture technique will be very difficult to counterfeit with a false finger, because it will be necessary both to have the design of the impression to be counterfeited, as well as a knowledge of the internal structure of the skin of the finger. the individual possessing the imprint and the spectral characteristics of this skin.
• Fingerprint image capture and spectral information capture will be done either sequentially or simultaneously, the latter being preferred.
• the captures can also be done in an interlaced manner: partial capture of image of imprint followed by a partial capture of spectral information, and again a partial capture of image of imprint, etc., with a verification of the consistency of the various catches, between catches or after catches.
• the impression image can be obtained statically or dynamically, in particular by optical, thermal or capacitive means.
• a static image capture the finger remains stationary during the fingerprint reading.
• a dynamic image capture or capture with scanning it is the finger which is moved on the sensor, or the sensor which is moved under a fixed finger; the overall image is reconstructed from partial images from a sensor having only a small number of lines of image points; the reconstruction is made by correlation between the partial images obtained successively during the relative displacement.
• the fingerprint image sensor is produced in principle on a silicon chip.
• the spectral information analysis photodiodes are preferably located on the same chip as the fingerprint image sensor.
• the light-emitting diodes which provide the light source for obtaining spectral information are located outside of the silicon chip for technological reasons (they are not in principle made from silicon).
• the fingerprint sensor may be smaller than what would be necessary in the absence of spectral recognition.
• the light-emitting diodes and the photodiodes can be arranged symmetrically with respect to an axis to carry out several measurements at various positions in an equivalent manner: arrangements according to two or four symmetrical sectors in particular.
• the photodiodes which are used for capturing spectral information can be the same as those which, in a matrix arrangement, are used for capturing fingerprint image.
• the invention proposes to correlate the spectral information of the skin section observed with the fingerprint slice observed at the same time.
• spectral recognition makes it possible to deduce certain parameters which will then be accepted with a certain range to overcome local variations in the skin.
• This technique can be used in the case of a static capture, but even more conveniently in the case of a scanning capture which will reduce costs (the silicon sensor will present a smaller surface) while retaining a wealth of information. important.
• the invention proposes that the fingerprint and spectral imprint captures are preferably carried out physically by the same photodiodes; the measurements will be made sequentially or better simultaneously.
• the invention proposes to interleave fingerprint capture and spectral fingerprint capture for make fraud difficult. Indeed, if we read the fingerprint and then the spectral fingerprint after the end of the fingerprint reading, then it would be potentially possible to present a counterfeit fingerprint and then a spectral counterfeit. If the measurement sequence is fast enough or interleaved, such as reading a footprint sector, making a spectral measurement with a first LED, then reading another sector, making a second spectral measurement, etc. then it becomes impossible to defraud by alternately presenting a false fingerprint and a false spectral fingerprint.
• FIG. 2 shows the device of Figure 1 in top view
• FIG. 3 shows an embodiment with photodiodes integrated on the same chip as the fingerprint image sensor
• FIG. 7 shows a sensor in which the image of the imprint is detected by movement of the finger on the surface of the sensor.
• Light emitting diode to designate the monochromatic or quasi-monochromatic light emitter for spectral recognition, knowing that it will most often be a light emitting diode, but that it can be any type of light emitter suitable for this measurement (laser, white light plus filter ). Several colors are used, therefore several diodes (or filters). The light emission is preferably in red and near infrared, for which there is both good penetration of light inside the skin, good blood response, and sufficient sensitivity of detectors produced from silicon.
• photodiode is used to refer to the light sensor that will convert the photons received into an electrical signal.
• Capturing the skin spectrum requires measuring the skin's optical response to light excitation for different optical wavelengths. Avoid measuring the light directly reflected by the surface or surface layers of the skin (stratum corneum). Indeed, the information specific to each individual is located in the structure of the dermis. It is therefore necessary that the light emitter (LED) is separated from the light sensor (photodiode) so that only the light which has passed through the skin reaches the sensor, minimizing the fraction of light which can reach directly or after simple reflection on the skin from the LED to the sensor. The choice of the distance between light emitter and detector makes it possible to act on the reduction of direct reflection.
• FIG. 1 represents, in section, the principle of the invention in which the fingerprint sensor and the spectral fingerprint sensor share the surface on which the finger presses during the person recognition operation.
• the fingerprint sensor (optical or not) is a matrix sensor 10 constituted by a silicon chip mounted on a substrate 20.
• An LED 12 is shown as well as a corresponding photodiode 14, mounted on the same substrate 20. In practice there are several LEDs, preferably corresponding to different wavelengths, and several photodiodes.
• the fingerprint sensor is significantly smaller than the finger in order to allow the skin to touch the spectral sensor at the same time in order to be able to make the captures with a single “touch” of the user. . Having a smaller fingerprint sensor significantly decreases recognition performance, in particular due to the fact that it is difficult to present exactly the same part of fingerprint each time. This loss of performance will be compensated by the additional information provided by spectral recognition.
• FIG. 2 represents a top view of the mixed sensor, with the image of finger 22 placed on the sensor superimposed.
• FIG. 3 represents, in section, a principle of embodiment with the photodiodes 14 incorporated in the silicon chip 10 constituting the fingerprint sensor.
• FIG. 4 represents a top view of the configuration of the mixed sensor of FIG. 3. The LEDs will preferably be controlled directly using the silicon chip 10 which can contain all the electronics necessary for fingerprint detection and the detection of spectral information.
• the increase in the number of photodiodes for spectral reading makes it possible to reduce the number of LEDs while increasing the accuracy of the measurement.
• FIG. 5 represents an embodiment in which the fingerprint sensor (silicon chip) is divided into four symmetrical zones each comprising several photodiodes, associated with LEDs arranged around the chip.
• FIG. 6 shows another embodiment with a division of the sensor into two symmetrical zones with respect to a horizontal axis.
• the photodiodes are located on either side of this axis, in the chip, and the LEDs are preferably located on the axis, on each side of the chip.
• the fingerprint detection matrix is a photodiodes matrix (optical fingerprint reading, static and direct contact)
• the photodiodes which are also used for the detection of the spectral imprint. It is then the LEDs that serve as a light source to illuminate the ridges and valleys of the fingerprints; the photodiodes collect a light pattern representing the fingerprint when all the LEDs are on; on the other hand, for obtaining spectral information, it is expected that the LEDs emit according to different wavelengths.
• a configuration such as that of FIG.
• the photodiodes of the detection array image located on an arc 30 centered on a determined LED 32 receive spectral information from the same dermis depth, constituting an element of the overall spectral recognition that can be obtained from the other LEDs.
• the different wavelengths of LEDs and the different positions of photodiodes in the matrix make it possible to define an overall spectral imprint.
• LEDs of various wavelengths will be placed around the static optical sensor with direct contact. They will then have two uses: on the one hand, all or part of the LEDs will be simultaneously lit in order to light the finger enough to allow the capture of the fingerprint using the matrix of photodiodes connected to an electronic adapted to this usage. On the other hand, only one wavelength will be activated to allow the measurement of the spectral imprint using the same photodiodes connected to electronics adapted to this spectral reading.
• FIG. 7 represents a corresponding configuration of the mixed sensor, with a silicon chip in the form of an elongated strip, containing at the same time a few lines of photodiodes for the fingerprint image capture and photodiodes for capturing spectral information, the light emitting diodes being located outside of the silicon chip.
• the preferable implementation of the invention will consist in using a scanning optical print capture associated with the capture of the spectral print, where the photodiodes will be physically the same. This minimizes the elements necessary for data acquisition, and thereby
• the light-emitting diodes can be integrated, as far as technology allows, in the chip constituting the fingerprint sensor;
• the fingerprint sensor can be an optical sensor, but can also be a capacitive, thermal, pressure, current flow sensor;
• the light source may be common for capturing fingerprints and for capturing spectral information;
• - For the capture of spectral imprint one can use a wavelength used for the detection of blood in the finger, and / or the level of oxygen in the hemoglobin;
• the finger can be guided by a finger guide to facilitate the correlation between the capture of a fingerprint and the measurement of spectral information;
• the device can be used once or several times for a more secure identification of a person: one can check several fingers, or check a fingerprint on one finger and the spectral information on another finger.

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• Engineering & Computer Science (AREA)
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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
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• Life Sciences & Earth Sciences (AREA)
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• Artificial Intelligence (AREA)
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• Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)

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• 2003
  • 2003-01-21 FR FR0300593A patent/FR2850190B1/fr not_active Expired - Fee Related
• 2004
  • 2004-01-16 CN CNA2004800025450A patent/CN1777896A/zh active Pending
  • 2004-01-16 KR KR1020057013390A patent/KR20050096142A/ko not_active Application Discontinuation
  • 2004-01-16 WO PCT/FR2004/000093 patent/WO2004068394A1/fr active Application Filing
  • 2004-01-16 CA CA002513412A patent/CA2513412A1/fr not_active Abandoned
  • 2004-01-16 US US10/541,395 patent/US20060115128A1/en not_active Abandoned
  • 2004-01-16 JP JP2006502103A patent/JP2006518068A/ja active Pending
  • 2004-01-16 EP EP04702735A patent/EP1586074A1/de not_active Withdrawn

Non-Patent Citations (1)

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