Live print scanner with holographic imaging a different magnifications
View Patent ↗This invention relates to the use of holographic optical elements in the design and application of biometric scanning instruments used typically for capturing biometric information such as fingerprints and handprints. A system and method for capturing print images from select areas of a platen are presented. The system includes a reference beam source that provides a reference beam, holographic material that receives the reference beam, a platen on a surface of the holographic material that receives a biometric object, and an image sensor. Variations in orientation of the reference beam cause differing areas of the platen to be mapped onto the image sensor, thereby obtaining both different image translations and magnifications of at least a portion of the biometric object.
1. A system for capturing light on an image sensor, the light being directed from select areas of a platen that are configured to receive a biometric object, the image sensor configured to form print images therefrom, comprising:
the image sensor;
a reference beam source configured to output a selected one of a plurality of reference beams, each of the reference beams having a different orientation; and
a holographic element, comprising,
a top surface having imaging areas corresponding to the select areas of the platen, the platen being supported by the top surface,
an end surface that receives the selected one of the plurality of reference beams,
a body portion configured to direct the reference beam from the end surface towards a respective one of the imaging areas and corresponding ones of the select areas based upon the orientation of the reference beam, the reference beam interacting with the biometric object through reflection from the top surface of the holographic element, such that, through frustrated total internal reflection between the reference beam and the biometric object, biometric information correlating to the biometric object is generated, and
a bottom surface configured to transmit the biometric information received from the top surface and the body portion of the holographic element toward the image sensor,
wherein different image translations or different magnifications of at least a portion of the biometric object are generated in the biometric information based on which of the select areas and which of the imaging areas the reference beam was directed towards by the body portion, which is based on the orientation of the reference beam.
2. The system of claim 1 , wherein the orientation of incidence of the reference beam at the end surface of the holographic element allows the biometric information from a large area of the biometric object to be directed onto the image sensor at a reduced resolution.
3. The system of claim 1 , wherein the orientation of incidence of the reference beam at the end surface of the holographic element allows the biometric information from a small area of the biometric object to be directed onto the image sensor at an increased resolution.
4. A method for capturing light on an image sensor, the light being directed from select areas of a platen that are configured to receive a biometric object, the image sensor configured to form print images therefrom, comprising:
outputting a selected one of a plurality of reference beams, each of the reference beams having a different orientation; and
supporting a platen on a top surface of a holographic element, the top surface having imaging areas corresponding to the select areas of the platen;
receiving the selected one of the plurality of reference beams at an end surface of the holographic element;
directing the reference beam from the end surface towards a respective one of the imaging areas and corresponding ones of the select areas based upon the orientation of the reference beam using a body portion of the holographic element, the reference beam interacting with the biometric object through reflection from the top surface of the holographic element, such that, through frustrated total internal reflection between the reference beam and the biometric object, biometric information correlating to the biometric object is generated; and
transmitting the biometric information received from the top surface and the body portion of the holographic element toward the image sensor via a bottom surface of the holographic element;
wherein different image translations or different magnifications of at least a portion of the biometric object are generated in the biometric information based on which of the select areas and which of the imaging areas the reference beam was directed towards by the body portion, which is based on the orientation of the reference beam.
5. The method of claim 4 , wherein the orientation of the reference beams received on the end surface of the holographic element allows biometric information from a large area of the biometric object to be directed onto the image sensor at a reduced resolution.
6. The method of claim 4 , wherein the orientation of the reference beams received on the end surface of the holographic element allows biometric information from a small area of the biometric object to be directed onto the image sensor at an increased resolution.