Spoof detection using localized illumination for biometric authentication systems
This document describes a biometric authentication system including a biometric authentication manager is configured to receive user input at a touch-sensitive display, determine a shape of the user input, and alter a luminosity and/or color of one or more portions of a region of the touch-sensitive display. Through such a technique, the biometric authentication manager can implement spatially, temporally, and/or chromatically variable illumination patterns to produce a fingerprint reflection, receive the fingerprint reflection, and then analyze the fingerprint reflection for authenticity and/or for liveness characteristics effective to detection spoof fingerprints.
1 . A method comprising:
receiving a fingertip touch input from a user, the fingertip touch input in contact with a touch-sensitive display;
determining, responsive to receiving the fingertip touch input, an irregularly-shaped contact area of the fingertip touch input in contact with the touch-sensitive display, the determining the irregularly-shaped contact area of the contact with the touch-sensitive display including:
receiving a raw heatmap; and
determining, based on the raw heatmap, a location of the irregularly-shaped contact area;
altering, responsive to determining the irregularly-shaped contact area of the contact, a color of light emitted by one or more portions of the touch-sensitive display within the irregularly-shaped contact area;
receiving a fingerprint reflection of the fingertip touch input, the fingerprint reflection being a reflection from the fingertip touch input caused by the altered color of light emitted from the one or more portions of the touch-sensitive display at the irregularly-shaped contact area; and
determining, based on the received fingerprint reflection, that the fingerprint reflection of the fingerprint touch input indicates a live, human finger.
2 . The method as described in claim 1 , further comprising, prior to determining the irregularly-shaped contact area or prior to altering the color of light, determining that a resource of a computing device associated with the touch-sensitive display is locked from access.
3 . The method as described in claim 2 , wherein the resource of the computing device associated with the touch-sensitive display is a resource requiring authentication prior to the access, the resource requiring authentication being a computer program, an internet-enabled account, or a peripheral device.
4 . The method as described in claim 3 , further comprising, responsive to determining that the received fingerprint reflection of the fingerprint touch input indicates a live, human finger and is authorized to access the resource of the computing device, unlocking the resource of the computing device.
5 . The method as described in claim 1 , further comprising, responsive to determining that the received fingerprint reflection of the fingerprint touch input indicates a live, human finger and is not authorized to access the resource of the computing device, denying access to the resource of the computing device.
6 . The method as described in claim 1 , further comprising, responsive to determining the irregularly-shaped contact area of the contact, altering a luminosity of light emitted by the one or more portions of the touch-sensitive display within the irregularly-shaped contact area.
7 . The method as described in claim 1 , wherein altering a color of light emitted by one or more portions of the touch-sensitive display within the irregularly-shaped contact area is sufficient to generate colored light.
8 . The method as described in claim 1 , wherein altering a color of light emitted by one or more portions of the touch-sensitive display within the irregularly-shaped contact area is sufficient to generate electromagnetic waves at frequency greater than 700 nanometers.
9 . The method as described in claim 1 , wherein altering the color of light is effective to amplify characteristics of the fingertip touch input in the fingerprint reflection.
10 . The method as described in claim 1 , wherein determining that the fingerprint reflection of the fingerprint touch input indicates a live, human finger is based on a machine-learned model trained to reject spoof fingers if the fingerprint reflection exhibits optical characteristics dissimilar to optical characteristics of live, human fingers.
11 . The method of claim 1 , wherein determining the irregularly-shaped contact area further includes calculation of a line drawing algorithm based on the raw heatmap.
12 . The method of claim 1 , wherein altering the color of light emitted by one or more portions of the touch-sensitive display within the irregularly-shaped contact area alters the color at an offset from a contour of the irregularly-shaped contact area.
13 . The method of claim 12 , where in the offset is determined based on at least one of an ambient light of an environment in which the touch-sensitive display resides, an amount of potential light leakage from the touch-sensitive display, a current brightness setting of the touch-sensitive display, a determined curvature of the user input, or a size of the irregularly-shaped contact area.
14 . An electronic device comprising:
an electronic visual display;
one or more processors; and
memory storing one or more programs to be executed by the one or more processors, the one or more programs comprising instructions for:
receiving a fingertip touch input from a user, the fingertip touch input in contact with a touch-sensitive display;
determining, responsive to receiving the fingertip touch input, an irregularly-shaped contact area of the fingertip touch input in contact with the touch-sensitive display, the determining the irregularly-shaped contact area of the contact with the touch-sensitive display including:
receiving a raw heatmap; and
determining, based on the raw heatmap, a location of the irregularly-shaped contact area;
altering, responsive to determining the irregularly-shaped contact area of the contact, a color of light emitted by one or more portions of the touch-sensitive display within the irregularly-shaped contact area;
receiving a fingerprint reflection of the fingertip touch input, the fingerprint reflection being a reflection from the fingertip touch input caused by the altered color of light emitted from the one or more portions of the touch-sensitive display within the irregularly-shaped contact area; and
determining, based on the received fingerprint reflection, that the fingerprint reflection of the fingerprint touch input indicates a live, human finger.
15 . The electronic device as described in claim 14 , wherein the one or more programs further comprise instructions for:
prior to determining the irregularly-shaped contact area or prior to altering the color of light, determining that a resource of a computing device associated with the touch-sensitive display is locked from access.
16 . The electronic device as described in claim 15 , where in the one or more programs further comprise instructions for:
responsive to determining that the received fingerprint reflection of the fingerprint touch input indicates a live, human finger and is authorized to access the resource of the computing device, unlocking the resource of the computing device; or
responsive to determining that the received fingerprint reflection of the fingerprint touch input indicates a live, human finger and is not authorized to access the resource of the computing device, denying access to the resource of the computing device.
17 . The electronic device as described in claim 14 , wherein the one or more programs further comprise instructions for:
responsive to determining an irregularly-shaped contact area of the contact, altering a luminosity of light emitted by the one or more portions of the touch-sensitive display within the irregularly-shaped contact area.
18 . The electronic device of claim 14 , wherein determining the irregularly-shaped contact area further includes calculation of a line drawing algorithm based on the raw heatmap.
19 . The electronic device of claim 14 , wherein altering the color of light emitted by one or more portions of the touch-sensitive display within the irregularly-shaped contact area alters the color at an offset from a contour of the irregularly-shaped contact area.
20 . The electronic device of claim 19 , wherein the offset is determined based on at least one of an ambient light of an environment in which the electronic device resides, an amount of potential light leakage from the touch-sensitive display, a current brightness setting of the touch-sensitive display, a determined curvature of the user input, or a size of the irregularly-shaped contact area.