Method and system for acoustic impediography biometric sensing
View Patent ↗Provided is a method for analyzing a fingerprint, including storing a captured fingerprint in a memory; and analyzing the stored fingerprint using acoustic sensing principles.
1. A method for capturing an image of a fingerprint in a sensing device, comprising:
placing fingerprint tissue of a finger in acoustical contact with a sensor matrix comprising an arrangement of piezo pillars:
generating oscillations and acoustic waves within said piezo pillars via an inverse piezo-eleetrical effect;
measuring an acoustic impedance load for each of said piezo pillars by measuring damping of oscillations for each of said piezo pillars;
distinguishing at least ore ridge from at least one valley of said fingerprint tissue based upon said acoustic impedance load for each of a plurality of said piezo pillars, and wherein
a first pillar within said matrix is configured to receive oscillation simultaneously with a second set of pillars within said matrix, said second set of pillars including at least one pillar that is adjacent to said first pillar, and including at least one pillar that is not adjacent to said first pillar, and wherein none of said second set of pillars has a surface that faces and is adjacent to a surface of said first pillar, and wherein
said pillars other than said first pillar and said second set of pillars, are not configured to receive said oscillation simultaneously with said first pillar and said second set of pillars.
2. The method of claim 1 wherein each of said pillars receiving oscillation is an active pillar that is located adjacent to at least one passive pillar within said matrix of piezo pillars.
3. The method of claim 1 wherein each of said pillars receiving oscillation is an active pillar that is non-diagonally adjacent to at least two passive piezo pillars.
4. The method of claim 1 wherein each of said piezo pillars has a square a cross-section.
5. The fingerprint sensing apparatus of claim 1 , wherein a distance between neighboring piezo pillars is a distance equal to about one quarter of a shear wave length.
6. A fingerprint sensing apparatus, comprising:
one or more devices for capturing an image of a fingerprint, each device including a matrix of piezo pillars; and wherein
said pillars are configured to receive oscillation via excitation forces and wherein said oscillation is affected by damping in response to an acoustic impedance load being applied to said pillars, and wherein
a first pillar within said matrix, is configured to receive oscillation simultaneously with a second set of pillars within said matrix, said second set ofpillais including at least one pillar that is adjacent to said first pillar, and including at least one pillar that is not adjacent to said first pillar, and wherein none of said second set of pillars has a surface that faces and is adjacent to a surface of said first pillar, and Wherein
said pillars other than said first pillar and said second set of pillars, are not configured to receive said oscillation simultaneously with said first pillar and said second set of pillars.
7. The apparatus of claim 6 wherein each of said pillars receiving oscillation is an active pillar that is located adjacent to at least one passive pillar within said matrix of piezo pillars.
8. The apparatus of claim 6 wherein each of said pillars receiving oscillation is an active pillar that is non-diagonally adjacent to at least two passive piezo pillars.
9. The apparatus of claim 6 wherein each of said piezo pillars has a square a cross-section.
10. The apparatus of claim 6 , wherein a distance between neighboring piezo pillars is a distance equal to about one quarter of a shear wave length.
11. The apparatus of claim 6 , wherein pillars receiving oscillation are active pillars that are located in an arrangement that includes a checker board pattern of active pillars within said matrix.
12. The apparatus of claim 6 , wherein each of said second set of pillars are located along any direction that is diagonal to said first pillar.
13. The apparatus of claim 6 , wherein each of said second set of pillars are located along any direction that is diagonal to at least one other pillar receiving oscillation.