Abstract: A method for restoring an image of a fingerprint sensor is described. The method includes capturing, by the fingerprint sensor, a fake fingerprint image from a fake fingerprint; calculating a phase of the fake fingerprint from the fake fingerprint image; capturing a plurality of target fingerprint images at measurement times by a fingerprint sensor disposed on a rear side of a display panel; applying the calculated phase to each of the acquired target fingerprint images; and combining information from each of the plurality of target fingerprint images to generate a final fingerprint image.

Abstract: A method for calculating a reference value of an ultrasonic sensor includes: transmitting a first ultrasonic signal from the ultrasonic sensor toward a first surface of a contact device while an object is positioned on the first surface; generating a plurality of ultrasonic images based on a first ultrasonic echo signal; selecting an ultrasonic image having a highest similarity to a reference image from among the ultrasonic images; storing a first parameter and a second parameter corresponding to a selected ultrasonic image; while the object is not positioned on the first surface, transmitting a second ultrasonic signal based on the first parameter from the ultrasonic sensor toward the first surface; and calculating the reference value of the ultrasonic sensor using the second parameter and a second ultrasonic echo signal.

Abstract: A fingerprint authentication device includes: a sensor unit configured to output a sensing signal by sensing a fingerprint; an image processing unit configured to generate a fingerprint image based on the sensing signal; a storage unit configured to store a template including an enrolled image; and a learning unit configured to generate a first pseudo image and add the first pseudo image to the template.

Abstract: A method for restoring an image of a fingerprint sensor is described. The method includes capturing, by the fingerprint sensor, a fake fingerprint image from a fake fingerprint; calculating a phase of the fake fingerprint from the fake fingerprint image; capturing a plurality of target fingerprint images at measurement times by a fingerprint sensor disposed on a rear side of a display panel; applying the calculated phase to each of the acquired target fingerprint images; and combining information from each of the plurality of target fingerprint images to generate a final fingerprint image.

Abstract: A method for calculating a reference value of an ultrasonic sensor includes: transmitting a first ultrasonic signal from the ultrasonic sensor toward a first surface of a contact device while an object is positioned on the first surface; generating a plurality of ultrasonic images based on a first ultrasonic echo signal; selecting an ultrasonic image having a highest similarity to a reference image from among the ultrasonic images; storing a first parameter and a second parameter corresponding to a selected ultrasonic image; while the object is not positioned on the first surface, transmitting a second ultrasonic signal based on the first parameter from the ultrasonic sensor toward the first surface; and calculating the reference value of the ultrasonic sensor using the second parameter and a second ultrasonic echo signal.

Abstract: An ultrasonic fingerprint sensing method includes: generating a first ultrasonic wave using a first frequency; receiving a first signal generated by reflection of the first ultrasonic wave from each of a ridge and a valley of a fingerprint; generating a first image based on the first signal; comparing the first image with a registered reference image to generate a matching score; and in response to the matching score being less than a threshold value, generating a second image using a second frequency.

Abstract: An ultrasonic fingerprint sensing method includes: generating a first ultrasonic wave using a first frequency; receiving a first signal generated by reflection of the first ultrasonic wave from each of a ridge and a valley of a fingerprint; generating a first image based on the first signal; comparing the first image with a registered reference image to generate a matching score; and in response to the matching score being less than a threshold value, generating a second image using a second frequency.

Abstract: A fingerprint authentication device includes: a sensor unit configured to output a sensing signal by sensing a fingerprint; an image processing unit configured to generate a fingerprint image based on the sensing signal; a storage unit configured to store a template including an enrolled image; and a learning unit configured to generate a first pseudo image and add the first pseudo image to the template.