US 11,928,795 B2
Filtering pulse-width modulated (PWM) noise from a fingerprint image captured with an optical under-display fingerprint sensor (UDFPS)
Firas Sammoura, Dublin, CA (US); and Omar Sze Leung, Palo Alto, CA (US)
Assigned to Google LLC, Mountain View, CA (US)
Appl. No. 17/769,193
Filed by Google LLC, Mountain View, CA (US)
PCT Filed Oct. 29, 2021, PCT No. PCT/US2021/057320
§ 371(c)(1), (2) Date Apr. 14, 2022,
PCT Pub. No. WO2022/186863, PCT Pub. Date Sep. 9, 2022.
Claims priority of provisional application 63/156,306, filed on Mar. 3, 2021.
Prior Publication US 2023/0139382 A1, May 4, 2023
Int. Cl. G06V 40/13 (2022.01); G06F 21/31 (2013.01); G06T 5/00 (2006.01); G06T 7/00 (2017.01)
CPC G06T 5/002 (2013.01) [G06F 21/31 (2013.01); G06T 7/0002 (2013.01); G06V 40/1318 (2022.01); G06T 2207/20182 (2013.01); G06T 2207/30168 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method comprising:
performing a principal component analysis on one or more background images associated with a sensor embedded under a display screen of a display system, the principal component analysis effective to reveal an artifact associated with pulse-width modulated (PWM) noise in the one or more background images;
determining PWM noise based at least in part on an extraction of principal component vectors from the artifact associated with PWM noise in the one or more background images;
responsive to determining the PWM noise, vectorizing the PWM noise to create a PWM noise vector;
illuminating, with light emitted from the display system, a user touch at the display screen, the illumination effective to produce a reflection of light associated with skin of a user;
capturing the reflection of light at the sensor to provide a user-associated image;
projecting the user-associated image onto a vector space, the vector space being associated with the PWM noise vector to provide the user-associated image on the vector space; and
based on the user-associated image on the vector space, filtering out the PWM noise from the user-associated image to provide a reduced-noise image.