Classifications

• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; 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
  • G06V40/13—Sensors therefor
  • G06V40/1324—Sensors therefor by using geometrical optics, e.g. using prisms
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V30/00—Character recognition; Recognising digital ink; Document-oriented image-based pattern recognition
  • G06V30/10—Character recognition
  • G06V30/14—Image acquisition
  • G06V30/144—Image acquisition using a slot moved over the image; using discrete sensing elements at predetermined points; using automatic curve following means

Definitions

• the invention relates to a fingerline profile registration system comprising a sequentially pixel wise acting fingerprint registration device.
• a fingerprint profile registration system as listed in the preamble is characterized in that said sequentially acting device is arranged to registrate a first part of an exposed skin area and an imaging device is added to the system to registrate a second part of the exposed skin area enabling a high speed, simultaneous imaging of a fingerprint to be examined. Due to the fact that a fingerprint profile registration system according to the invention comprises as well a point to point, thus a sequential pixel wise imaging registration as a television camera, thus a simultaneous imaging device, a very reliable and high speed imaging can be realised.
• a fingerprint profile registration system as described in WO 93- 18486 is capable to measure fingerline properties in great detail, only a small skin area is needed for verification, provided identical parts of the exposed skin are measured.
• CCD-camera type of fingerprint recognition systems are based on comparing the location of typica and therefore the accuracy increases with increasing test area or in other words missing a small part of a test area in the centre makes no difference if the same area also is excluded in the initial registration proces. For this reason use is made in a preferred embodiment of the invention of a glass parallopipid with a small hole pe ⁇ endicular to the largest surface of said parallopipid. In this hole a reflective elastomer is placed as support for part of the skin surface to be investigated.
• the choice which of the imaging means will be used is denoted by the reliability of the registration in search but for example also by the quality of the object to be registrated, thus of the shape of the fingerprint or of an image thereof.
• the simultaneous imaging device is provided with a CCD camera comprising a number of imaging pixel elements adapted to the resolving power of the registration system.
• a CCD camera comprising a number of imaging pixel elements adapted to the resolving power of the registration system.
• Such a camera is cheap, is very reliable and has a high dynamic range in control and read out.
• Useful CCD camera systems are commercially availably.
• a fingerline profile registration system provided with a CCD camera is known per s ⁇ from EP 300167. An apparatus disclosed therein suffers from a restricted resolving power and as a consequence the reliability can be unsufficient for a lot of applications.
• a further preferred embodiment comprises means for selecting as yet sequentially to registrate object parts selected from images generated by a simultaneously imaging device.
• Such a discriminator enables the combination of a high speed camera registration and a light-pen registration of image parts of the profile which are unsufficient accurate for further registration or of image parts having a relatively high density of profile characteristics.
• a sequential optical scanning device is provided with means for the use of focussing signals as height or dept defining signals (z-signals). Using these height focussing signals for a light-pen device the light-pen does not need any mechanical z movement. This fact increases the speed of scanning and results in a cheaper and more reliable device.
• a further enbodiment comprises an opto-mechanical x-y scanning device provided with a pair of wedges Iocated in the beampath of the scanning light beam, which wedges are axially rotatable in a reverse sence with respect to one another such that the scanning light beam executes a linear x-y scanning
• the fundamental advantage of such an embodiment is that mechanical turning points occurring in a normal opto-mechanical scanning device are avoided.
• the two wedges have merely to be rotated continously in a reverse sence to one another.
• Such a scanning can be very fast whilst the device becomes mechanical reliable and relatively cheap.
• signals generated by a simultaneously acting imaging device are used to control an opto-mechanical scanning system.
• segmented line transformation methods are used for fingerline profile characterisation.
• Such methods per se are known from the literature for example from JEEE transactions on pattern analysis and machine intelligence vol 16 no 5 May 1994 pp 513-519 and thus need no further explanation here. These methods delever a very reliable line characterisation and show a high dynamic range for adapting to the shape of the line to be characterised.
• a further embodiment according to the invention is provided with means for a point-to-point registration of relative angle variation of a tangent running along a line to be registrated.
• This menthod of registration is based on the knowledge that the shape of a fingerline is fully defined by a function K (s) on a line segment s whereby s denotes the running path part meansured along a fingerline and K (s) equals d ⁇ / d s wherein Q (s) is the local angle between the line and the tangent.
• K (s) the running path part meansured along a fingerline
• K (s) equals d ⁇ / d s
• Q (s) is the local angle between the line and the tangent.
• Fig. 1 shows schematically a registration system according to the invention
• Fig. 2 shows a rotable wedge system to be used in such a system
• Fig. 3 shows an embodiment of a coding line transformation therein.
• a registration apparatus as showed in figure 1 is provided with a pierced trurr.cated prism 2 having a hole 3 provided with a reflecting elastomer skin support 5 a object surface 4 preferably forming part of the base plane 3 of a rectangular prism.
• the object surface 4 is illuminated with a lightbeam 10 from a light soure 6 via a prism surface 8.
• a lightbeam 12 refleted on the object surface 4 strikes, running through a prism surface 14 an entrance screen of a camera 16.
• the camera 16 prefarably has the shape of a CCD camera in which the number of light sensitive elements is adapted to an image resolution to be realised.
• the camera is connected to a signal processing device 18 for registration, processing, recording and control of image signals of a fingerline profile 20 positioned against the object surface 4. In this manner a fingerline profile can be recordered rapidly and can be analysed for further use.
• a light beam 24 of a light pen system 22 passes through a mirror 26 and an x - y - z scanning system 28, an objective lens 30 and a field lens 32 a top surface 34 of, in this case a truncated prism 2, and also strikes the object surface 4.
• a lightbeam reflected on the object surface strikes, running in a reverse direction, for example a photo diode system 36 of the light pen system.
• Arrows x and z in figure 1 define the relevant scanning directions.
• the y-scan is directed square to the drawing surface. Via a connection 40 the scanning system is coupled to a signal processing unit 18.
• a mechanical z movement for the relevant scanning can be avoided by means 41 arranged to obtain z values from the local focussing signals for the light pen system.
• camera image signals can be used for light-pen system control via a connection 42.
• Futher means 43 can be added to generate a point - to - point registration of the relative angle variation of the tangent running along the fingerline to be recorded.
• the system can furtheron be completed by adding signal processing units well known per se for example to select characteristic data for an on - line comparison of recorded data with data stocked in a memory etc.
• An optical scanning system as shown in figure 2 is provided with a first optical wedge 50, a second optical wedge 52 being mounted in a support 54 and a support 56 respectivily.
• the wedges are mutually coupled enabling rotation in a mutually reverse sense with respect to one another as indicated with arrows 58 and 60.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Multimedia (AREA)
• Theoretical Computer Science (AREA)
• Computer Vision & Pattern Recognition (AREA)
• Optics & Photonics (AREA)
• Human Computer Interaction (AREA)
• Image Input (AREA)
• Facsimile Scanning Arrangements (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=19761642

Family Applications (1)

Country Status (3)

Families Citing this family (2)

• 1995
  • 1995-09-28 NL NL1001307A patent/NL1001307C1/nl not_active IP Right Cessation
• 1996
  • 1996-09-24 WO PCT/NL1996/000371 patent/WO1997012340A2/en not_active Ceased
  • 1996-09-24 EP EP96932857A patent/EP0807296A2/de not_active Withdrawn

Non-Patent Citations (1)

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