Finger/non-finger determination for biometric sensors
First Claim
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1. A fingerprint sensing apparatus, comprising:
- a fingerprint sensor system including an ultrasonic sensor array; and
a control system capable of;
receiving fingerprint sensor data from the fingerprint sensor system;
determining that an object is positioned proximate a portion of the fingerprint sensor system;
determining an acoustic impedance of at least a portion of the object;
determining whether the acoustic impedance is within an acoustic impedance range corresponding to that of skin; and
determining, based at least in part on the acoustic impedance, whether the object is a finger, wherein;
determining whether the object is a finger involves detecting patterns associated with fingerprints;
detecting patterns associated with fingerprints involves evaluating fingerprint sensor data blocks for at least a portion of the fingerprint sensor data; and
the fingerprint sensor data blocks correspond to blocks of fingerprint sensor pixels of the fingerprint sensor system.
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Abstract
Some methods may involve determining whether an object is positioned on or near a portion of a fingerprint sensor system. If an object is positioned on or near the portion of the fingerprint sensor system, an acoustic impedance of at least a portion of the object may be determined. Based at least in part on the acoustic impedance, it may be determined whether the object is a finger.
147 Citations
29 Claims
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1. A fingerprint sensing apparatus, comprising:
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a fingerprint sensor system including an ultrasonic sensor array; and a control system capable of; receiving fingerprint sensor data from the fingerprint sensor system; determining that an object is positioned proximate a portion of the fingerprint sensor system; determining an acoustic impedance of at least a portion of the object; determining whether the acoustic impedance is within an acoustic impedance range corresponding to that of skin; and determining, based at least in part on the acoustic impedance, whether the object is a finger, wherein; determining whether the object is a finger involves detecting patterns associated with fingerprints; detecting patterns associated with fingerprints involves evaluating fingerprint sensor data blocks for at least a portion of the fingerprint sensor data; and the fingerprint sensor data blocks correspond to blocks of fingerprint sensor pixels of the fingerprint sensor system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method, comprising:
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receiving fingerprint sensor data from a fingerprint sensor system; determining that an object is positioned proximate a portion of the fingerprint sensor system; determining an acoustic impedance of at least a portion of the object; determining whether the acoustic impedance is within an acoustic impedance range corresponding to that of skin; and determining, based at least in part on the acoustic impedance, whether the object is a finger and whether the object is a stylus, and wherein; determining whether the object is a finger involves detecting patterns associated with fingerprints; detecting patterns associated with fingerprints involves evaluating fingerprint sensor data blocks for at least a portion of the fingerprint sensor data; and the fingerprint sensor data blocks correspond to blocks of fingerprint sensor pixels of the fingerprint sensor system.
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23. A non-transitory medium having software stored thereon, the software including instructions for controlling a fingerprint sensing apparatus to:
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receive fingerprint sensor data from a fingerprint sensor system; pre-process the fingerprint sensor data, wherein pre-processing the fingerprint sensor data involves; identifying malfunctioning sensor pixels, the malfunctioning sensor pixels including at least one of dead sensor pixels or low-performing sensor pixels; and excluding fingerprint sensor data from the malfunctioning sensor pixels; determine that an object is positioned proximate a portion of the fingerprint sensor system; determine an acoustic impedance of at least a portion of the object; determine whether the acoustic impedance is within an acoustic impedance range corresponding to that of skin; and determine, based at least in part on the acoustic impedance, whether the object is a finger. - View Dependent Claims (24, 25, 26, 27)
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28. A fingerprint sensing apparatus, comprising:
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a fingerprint sensor system including an ultrasonic sensor array; and control means for; receiving fingerprint sensor data from the fingerprint sensor system; determining that an object is positioned proximate a portion of the fingerprint sensor system; determining an acoustic impedance of at least a portion of the object; determining whether the acoustic impedance is within an acoustic impedance range corresponding to that of skin; and determining, based at least in part on the acoustic impedance, whether the object is a finger, wherein; determining whether the object is a finger involves detecting patterns associated with fingerprints; detecting patterns associated with fingerprints involves evaluating fingerprint sensor data blocks for at least a portion of the fingerprint sensor data; and the fingerprint sensor data blocks correspond to blocks of fingerprint sensor pixels of the fingerprint sensor system. - View Dependent Claims (29)
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Specification