A method and apparatus for fingerprint recognition is provided. A fingerprint is detected on a sensor. The fingerprint is digitized. A digitized background is subtracted from the fingerprint, resulting in a difference print. The difference print is matched with a database of fingerprint templates.

Fingerprint recognition system

A method and apparatus for verification of personnel identity by correlation of fingerprint images. The method includes the steps of: first enrolling a person by the steps of forming a reference image of a fingerprint of the person, identifying a plurality of reference sections within the reference image, where the image data contained in each of the reference sections is distinct relative to the image data adjacent to and surrounding the reference section, and saving the image data of each of the reference sections; and then verifying the identity of someone claiming to be an enrolled person by the steps of retrieving the image data of the reference sections of the enrolled person, forming a verify image of the fingerprint of the person claiming to be enrolled, where the verify image includes a plurality of verify regions each corresponding in position to one of the reference sections and each larger in extent than its corresponding reference section, determining a best-match location within each verify region at which the image data is most similar to the image data of its corresponding reference section, and verifying the identity of the person claiming to be enrolled according to the degree of similarity between the image data of the best-match locations and the corresponding reference sections and according to the degree of similarity between the relative positioning of the best-match locations and the corresponding reference sections.

Method and apparatus for verifying identity using image correlation

There is provided an ergonomic fingerprint acquisition device comprising a housing having first and second exterior surfaces, the housing enclosing: a platen; a light source for irradiating the platen and any digit thereon with light; a light conducting plate; and image sensing device. The platen is disposed in register with an aperture in the first exterior surface. The second exterior surface is displaced from the first exterior surface to provide a grasping surface. The housing has a prehensile shape such as a sphere to permit grasping the first and second exterior surfaces while the person's digit presses on the platen so that the digit applies even pressure to the platen and a broad print of the digit is acquired. The print may be conveyed to a remote location by a conductive wire, optical cable, infrared, inductive pickup, or radio frequency. In addition, the device may be combined with a data extracting device and perhaps a matching device for matching the print to data extracted from a card or food stamp. The device may be used in a notarization system for authenticating that a transaction to be charged against an account has been authorized by an account holder or in combination with a set-top box for use with a television set of the type that provides one or more operators with adjustable features including an adjustable service level and preference setting.

Ergonomic fingerprint reader apparatus

A method and apparatus for generating a cryptographic key using biometric data is provided. A fingerprint is received, and features are extracted from the fingerprint (315). Theses features may include one or more of the following: a message is created based on the features of the fingerprint. For one embodiment, the message is a template including the features (320). For another embodiment, the message is a subset of features not included in a template. A message digest function is applied to the message to create a cryptographic key (355). Another embodiment of the present invention uses features of the fingerprint image to generate a digital certificate. The public key used for the digital certificate is based on a fingerprint image.

Cryptographic key generation using biometric data

A low-power, fully self-contained fingerprint capture, enrollment and verification method and device (100) The device includes a logic unit (110), a memory (120), a fingerprint sensor (130) and an interface (150) to an external unit (140) Included in the memory is a program (126) that includes a sensor data capture module (200), an image processing module (202), a minutia extraction module (204), a template creation module (206), a template compare module (208), and a database (210) The processes for capturing, enrolling and verifying a fingerprint are designed to be minimally computationally intensive This allows implementation of these processes in a portable, battery-powered unit using hardware with limited memory and computing capability, or implementation in a PC with substantial performance advantages relative to known fingerprint capture, enrollment and verification processes and devices Fingerprint verification is performed using fingerprint templates storing information as to location and type of minutia point, and direction of fingerprint ridge leading to the minutia point, rather than full image-to-image comparison

System and method for capturing, enrolling and verifying a fingerprint

A curved cylindrical segment platen has a concave touching surface. An interrogating slit light beam is scanned around the platen to scan a finger held against the touching surface. An optical imaging system images the zone illuminated onto an array of photo-transducers to provide a signal representing the fingerprint. The optical system is rotated around the platen. The axis of the interrogating light beam is substantially normal to the touching surface. The axis of the imaging system is off normal by about 56 degrees, an amount which is greater than a critical angle equal to the maximum angle of refraction in the platen. This critical angle is approximately 41 degrees. The axis of the imaging system is also off normal to the non-touching surface by an angle that is less than this critical angle of 41 degrees and thus less than the angle of total internal reflection. As a consequence, the image at the photo-transducers provides a completely dark valley zone and a sharply contrasting light image ridge zone. In a second embodiment, a thick flat platen has a flat touching surface and an opposed parallel flat surface through which an illuminating light beam is applied to scan across a finger applied to the touching surface. The illuminating beam is normal to the touching surface. The axis of the imaging system is at an angle of approximately 50 degrees to the normal, an angle that is thus well past 41 degrees, the maximum angle of refraction. The platen has a side face which is at an angle of 45 degrees to the touching surface. The imaging axis emerges from this sloping side face at an angle to the normal that is substantially less than the angle of total internal reflection.

Finger imaging apparatus using curved platen

The technique for optically scanning a finger to produce a fingerprint image involves positioning the finger surface to be optically scanned so that it is exposed and, in particular, is not pressed against a platen. A slit light beam along the length of the forward part of the finger is circumferentially rotated about an axis about the nominal center of the finger. A reflected slit light beam carries modulation information which is focused on a linear array of photo-electric transducers to provide the fingerprint image. The interrogating light is coherent, substantially collimated, light. The plane of the interrogating slit light beam and the plane of the reflected modulated slit light beam are coplanar thereby establishing an illumination plane. The illumination plane is parallel to the axis of the finger and is rotated about that axis during the interrogating scan. The illumination plane is slightly offset from that rotational axis and the incident light in the illumination plane impinges on the finger surface at a slight off-normal axis. This offset and off-normal incidence creates two dimensional shadowing. The finger surface being interrogated is positioned slightly off of the object plane for the downstream focusing optics thereby creating a constructive and destructive interference effect at the image plane defined by the transducers.

Direct finger reading

A curved cylindrical segment platen (18) has a concave touching surface (18b). An interrogating slit light beam is scanned around the platen to scan a finger held against the touching surface. An optical imaging system images (20) the zone illuminated onto an array of photo-transducers (22) to provide a signal representing the fingerprint. The optical system is rotated (40) around the platen. The axis (17) of the interrogating light beam (16) is substantially normal to the touching surface (18b). The axis (28a) of the imaging system is off normal by about 56 degrees, an amount which is greater than a critical angle equal to the maximum angle of refraction (MAR) in the platen. This critical angle is approximately 41 degrees. The axis (28) of the imaging system is also off normal to the non-touching surface (18a) by an angle that is less than this critical angle of 4l degrees and thus less than the angle of total internal reflection (TIR). As a consequence, the image at the photo-transducers provides a completely dark valley zone and a sharply contrasting light image ridge ,zone.

Michael Schiller

Papers

Finger imaging apparatus using curved platen

Direct finger reading

Finger imaging apparatus