CPC G06K 19/0718 (2013.01) [G06F 21/32 (2013.01); G06K 19/07354 (2013.01); G06T 5/50 (2013.01); G06T 7/80 (2017.01); G06V 40/1306 (2022.01); G06V 40/1335 (2022.01); G06V 40/1365 (2022.01); G06T 2207/20021 (2013.01); G06T 2207/20221 (2013.01)] | 19 Claims |
1. A method of a fingerprint sensing system arranged in a smartcard, the fingerprint sensing system being configured to acquire fingerprint data of a user with a fingerprint sensor for biometric authentication, comprising:
detecting a finger of the user contacting a sensing area of the fingerprint sensor;
initializing the fingerprint sensor with a predetermined sensor setting;
acquiring, for the finger being detected to contact the sensing area of the fingerprint sensor, a calibration sub-image which is confined in size to a subarea of the sensing area;
determining whether or not a quality criterion is met for the acquired calibration sub-image, and if so;
acquiring one or more further sub-images, each of the one or more further sub-images being confined in size to a further subarea of the sensing area; and
combining a plurality of the acquired further sub-images into a representation of a fingerprint of the user, wherein the further sub-images are acquired during a time period when the smartcard is not engaged in waiting time extension, WTX, request signalling with a card reader with which the smartcard performs contactless communication.
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