Fingerprint sensor image calibration method, electronic device, and non-transitory computer-readable storage medium

Patent metadata

Field	Value
Publication number	US-12183116-B2
Application number	US-202117523866-A
Country	US
Kind code	B2
Filing date	Nov 10, 2021
Priority date	May 29, 2019
Publication date	Dec 31, 2024
Grant date	Dec 31, 2024

Abstract

A calibration method, an electronic device, and a non-transitory computer-readable storage medium are provided. The calibration method is applicable to an electronic device including a fingerprint sensor. The calibration method includes the following. Fingerprint collection is performed with the fingerprint sensor to obtain a first fingerprint image. A first numerical value is determined according to the first fingerprint image, a first calibration image, and a second calibration image, where the first numerical value is indicative of a change in brightness of a light source for the fingerprint collection, the first calibration image is an image obtained by performing image collection on a bright surface of a calibration box, and the second calibration image is an image obtained by performing image collection on a dark surface of the calibration box. The first fingerprint image is calibrated according to the first numerical value to obtain a second fingerprint image.

First claim

What is claimed is:

1. A calibration method, being applicable to an electronic device comprising a fingerprint sensor, the calibration method comprising:
performing fingerprint collection with the fingerprint sensor to obtain a first fingerprint image;
determining a first numerical value according to the first fingerprint image, a first calibration image, and a second calibration image, wherein the first numerical value is indicative of a change in brightness of a light source for the fingerprint collection, the first calibration image is an image obtained by performing image collection on a bright surface of a calibration box, and the second calibration image is an image obtained by performing image collection on a dark surface of the calibration box, wherein the calibration box is used for performing calibration and comprises two fixed reflective surfaces comprising the bright surface and the dark surface; and
calibrating the first fingerprint image according to the first numerical value to obtain a second fingerprint image.

2. The calibration method of claim 1 , further comprising:
prior to determining the first numerical value according to the first fingerprint image, the first calibration image, and the second calibration image,
determining that an event to be unlocked corresponding to the fingerprint collection is a set unlocking event.

3. The calibration method of claim 2 , wherein a matching degree of fingerprint verification required by the set unlocking event is greater than or equal to a threshold.

4. The calibration method of claim 1 , further comprising:
prior to determining the first numerical value according to the first fingerprint image, the first calibration image, and the second calibration image,
determining that a current system time is within a set time period.

5. The calibration method of claim 1 , further comprising:
prior to determining the first numerical value according to the first fingerprint image, the first calibration image, and the second calibration image,
determining whether a time interval between a time at which a third fingerprint image is collected and a current system time is greater than or equal to a threshold, wherein the third fingerprint image is collected before the first fingerprint image; wherein
determining the first numerical value according to the first fingerprint image, the first calibration image, and the second calibration image comprises:
determining the first numerical value according to the first fingerprint image, the first calibration image, and the second calibration image, in response to determining that the time interval between the time at which the third fingerprint image is collected and the current system time is greater than or equal to the threshold.

6. The calibration method of claim 5 , further comprising:
calibrating the first fingerprint image according to a numerical value for calibration of the third fingerprint image to obtain a fourth fingerprint image, in response to the time interval between the time at which the third fingerprint image is collected and the current system time being less than the threshold.

7. The calibration method of claim 1 , further comprising:
after calibrating the first fingerprint image according to the first numerical value to obtain the second fingerprint image,
obtaining, in response to failure of fingerprint verification with the second fingerprint image, a target fingerprint image by performing image calibration according to a signal value matrix of the first fingerprint image, a signal value matrix of the second calibration image, and a third function, wherein the third function is: r2=Raw−RL, wherein r2 represents a signal value matrix of a fingerprint image calibrated, Raw represents a signal value matrix of a fingerprint image without calibration, and RL represents a signal value matrix of a calibration image corresponding to the dark surface of the calibration box; and

performing fingerprint verification with the target fingerprint image.

8. An electronic device, comprising:
a fingerprint sensor;
a processor; and
a memory coupled to the processor and storing one or more programs;
the one or more programs which, when executed by the processor, cause the processor to:
perform fingerprint collection with the fingerprint sensor to obtain a first fingerprint image;
determine a first numerical value according to the first fingerprint image, a first calibration image, and a second calibration image, wherein the first numerical value is indicative of a change in brightness of a light source for the fingerprint collection, the first calibration image is an image obtained by performing image collection on a bright surface of a calibration box, and the second calibration image is an image obtained by performing image collection on a dark surface of the calibration box, wherein the calibration box is used for performing calibration and comprises two fixed reflective surfaces comprising the bright surface and the dark surface; and
calibrate the first fingerprint image according to the first numerical value to obtain a second fingerprint image.

9. The electronic device of claim 8 , wherein the one or more programs, when executed by the processor, further cause the processor to:
determine that an event to be unlocked corresponding to the fingerprint collection is a set unlocking event, prior to determining the first numerical value according to the first fingerprint image, the first calibration image, and the second calibration image.

10. The electronic device of claim 8 , wherein the one or more programs, when executed by the processor, further cause the processor to:
determine that a current system time is within a set time period, prior to determining the first numerical value according to the first fingerprint image, the first calibration image, and the second calibration image.

11. The electronic device of claim 8 , wherein the one or more programs, when executed by the processor, further cause the processor to:
prior to determining the first numerical value according to the first fingerprint image, the first calibration image, and the second calibration image,
determine whether a time interval between a time at which a third fingerprint image is collected and a current system time is greater than or equal to a threshold, wherein the third fingerprint image is collected before the first fingerprint image, wherein
the one or more programs executed by the processor to determine the first numerical value according to the first fingerprint image, the first calibration image, and the second calibration image are executed by the processor to:
determine the first numerical value according to the first fingerprint image, the first calibration image, and the second calibration image, in response to determining that the time interval between the time at which the third fingerprint image is collected and the current system time is greater than or equal to the threshold.

12. The electronic device of claim 11 , wherein the one or more programs, when executed by the processor, further cause the processor to:
calibrate the first fingerprint image according to a numerical value for calibration of the third fingerprint image to obtain a fourth fingerprint image, in response to the time interval between the time at which the third fingerprint image is collected and the current system time being less than the threshold.

13. The electronic device of claim 8 , wherein the one or more programs, when executed by the processor, further cause the processor to:
obtain, in response to failure of fingerprint verification with the second fin

Assignees

• Guangdong Oppo Mobile Telecommunications Corp Ltd

Inventors

• Zhan Wenxi
• Chen Biao

Classifications

• G06F21/32 Primary

  using biometric data, e.g. fingerprints, iris scans or voiceprints · CPC title

• G06V40/1353

  Extracting features related to minutiae or pores · CPC title

• G06T7/97

  Determining parameters from multiple pictures (depth or shape recovery from multiple images G06T7/55; stereo camera calibration G06T7/85) · CPC title

• G06V40/1318 Primary

  using electro-optical elements or layers, e.g. electroluminescent sensing · CPC title

• G06F3/041 Primary

  Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means · CPC title