Method for controlling unlocking and terminal

1. A method for controlling unlocking, comprising: detecting a touch operation of a finger of a user on a fingerprint recognition sensor of a terminal;

receiving a first fingerprint image according to a preset capacity auto control (CAC) parameter corresponding to a default finger, wherein the finger of the user is in a steady state;

receiving N sets of second fingerprint images, according to N sets of CAC parameters, wherein N is an integer greater than 1, during the receiving of the first fingerprint image;

determining a target fingerprint image, wherein the target fingerprint image is the best fingerprint image among the first fingerprint image and the N sets of second fingerprint images; matching the target fingerprint image;

unlocking the terminal when the target fingerprint image is matched; and

determining an application interface that is loaded and displayed the most in a preset time period during the matching the target fingerprint image, and loading and displaying the application interface, wherein the preset time period comprises a current system time.

2. The method of claim 1 , further comprising:

before receiving the first fingerprint image, determining whether the finger of the user is in the steady state, wherein determining whether the finger of the user is in the steady state comprises:

receiving at least two third fingerprint images; and

determining whether the finger of the user is in the steady state based on a difference between the at least two third fingerprint images.

3. The method of claim 2 , wherein determining whether the finger of the user is in the steady state based on the difference between the at least two third fingerprint images comprises:

when a difference in clarity of the at least two third fingerprint images is less than or equal to a first threshold, determining that the finger of the user is in the steady state; and

when the difference in the clarity of the at least two third fingerprint images is greater than the first threshold, determining that the finger of the user is not in the steady state.

4. The method of claim 1 , wherein the fingerprint recognition sensor comprises R sensing electrodes, and the method further comprises:

determining whether the finger of the user is in the steady state before receiving the first fingerprint image, wherein determining whether the finger of the user is in the steady state comprises:

receiving at least two sets of data via the R sensing electrodes of the fingerprint recognition sensor, wherein each set of the at least two sets of data comprises R capacitance values, and R is an integer greater than 1; and

determining whether the finger of the user is in the steady state based on a difference between the at least two sets of data.

5. The method of claim 4 , wherein determining whether the finger of the user is in the steady state based on the difference between the at least two sets of data comprises:

when an average value of differences in the R capacitance values of the at least two sets of data is less than or equal to a second threshold, determining that the finger of the user is in the steady state; and

when the average value of the differences in the R capacitance values of the at least two sets of data is greater than the second threshold, determining that the finger of the user is not in the steady state.

6. The method of claim 1 , wherein the CAC parameter comprises an offset of an analog-to-digital converter (ADC) and a gain of the ADC, and the method further comprises:

before receiving the N sets of second fingerprint images according to the N sets of CAC parameters, determining K offsets of the ADC and H gains of the ADC, wherein K and H are integers greater than 1; and

constructing the N sets of CAC parameters according to the K offsets of the ADC and H gains of the ADC, wherein each set of the N sets of CAC parameters comprises one offset of the ADC and one gain of the ADC.

7. The method of claim 1 , wherein matching the target fingerprint image comprises:

extracting overall features of the target fingerprint image, and comparing the extracted overall features with overall features of a pre-stored fingerprint template of the terminal;

when the similarity between the extracted overall features of the target fingerprint image and the overall features of the pre-stored fingerprint template is greater than or equal to a third threshold, extracting local features of the target fingerprint image, and comparing the extracted local features with local features of the pre-stored fingerprint template; and

when the similarity between the extracted overall features and the overall features of the pre-stored fingerprint template is greater than or equal to a fourth threshold, determining that the target fingerprint image is matched.

8. A terminal, comprising a hardware processor configured to perform:

a detecting unit, configured to detect a touch operation of a finger of a user on a fingerprint recognition sensor of a terminal;

a receiving unit, configured to receive a first fingerprint image according to a default capacity auto control (CAC) parameter corresponding to a default finger, wherein the finger of the user is in a steady state, and receive N second fingerprint images according to N sets of CAC parameters during the receiving of the first fingerprint image, wherein N is an integer greater than 1;

a first determining unit, configured to determine a target fingerprint image, wherein the target fingerprint image is the best fingerprint image among the first fingerprint image and the N second fingerprint images;

a fingerprint comparing unit, configured to match the target fingerprint image; and an unlocking unit, configured to unlock the terminal when the target fingerprint image is matched; and determine an application interface that is loaded and displayed the most in a preset time period during the matching the target fingerprint image, and load and display the application interface, wherein the preset time period comprises a current system time.

9. The terminal of claim 8 , wherein the receiving unit is further configured to receive at least two third fingerprint images and the hardware processor is further configured to perform a second determining unit, wherein the second determining unit is configured to:

determine whether the finger of the user is in the steady state based on a difference between the at least two third fingerprint images.

10. The terminal of claim 9 , wherein the second determining unit is configured to:

determine clarity of each of the at least two third fingerprint images, and determine a difference in the clarity of the at least two third fingerprint images;

determine that the finger of the user is in the steady state when the difference in the clarity of the at least two third fingerprint images is less than or equal to a first threshold; and

determine that the finger of the user is not in the steady state when the difference in the clarity of the at least two third fingerprint images is greater than the first threshold.

11. The terminal of claim 8 , wherein

the fingerprint recognition sensor comprises R sensing electrodes,

the receiving unit is further configured to receive at least two sets of data via the R sensing electrodes of the fingerprint recognition sensor, wherein each set of the at least two sets of data comprises R capacitance values, and R is an integer greater than 1, and

the hardware processor is further configured to perform a second determining unit, wherein the second determining unit is configured to:

determine whether the finger of the user is in the steady state based on a difference between the at least two sets of data.

12. The terminal of claim 11 , wherein the second determining unit is further configured to:

determine that the finger of the user is in the steady state when an average value of differences in the R capacitance values of the at least two sets of data is less than or equal to a second threshold; and

determine that the finger of the user is not in the steady state when the average value of the differences in the R capacitance values of the at least two sets of data is greater than the second threshold.

13. The terminal of claim 8 , wherein the CAC parameter comprises an offset of an analog-to-digital converter (ADC) and a gain of the ADC, and the hardware processor is further configured to perform:

a third determining unit, configured to determine K offsets of the ADC and H gains of the ADC, and construct the N sets of CAC parameters according to the K offsets of the ADC and H gains of the ADC, wherein K and H are integers greater than 1, and each set of the N sets of CAC parameters comprises one offset of the ADC and one gain of the ADC.

14. The terminal of claim 8 , wherein the fingerprint comparing unit is configured to:

extract overall features of the target fingerprint image, and compare the extracted overall features with overall features of a pre-stored fingerprint template of the terminal;

extract local features of the target fingerprint image, and compare the extracted local features with local features of the pre-stored fingerprint template when the similarity between the extracted overall features and the overall features of the pre-stored fingerprint template is greater than or equal to a third threshold; and

determine that the target fingerprint image is matched when the similarity between the extracted overall features and the overall features of the pre-stored fingerprint template is greater than or equal to a fourth threshold.

15. A method for controlling unlocking, comprising: detecting a touch operation of a finger of a user on a fingerprint recognition sensor of a terminal;

receiving a first fingerprint image according to a default capacity auto control (CAC) parameter corresponding to a default finger, where the finger of the user is in a steady state;

receiving N second fingerprint images according to N sets of CAC parameters during the receiving of the first fingerprint image and matching the first fingerprint image, wherein N is an integer greater than 1; and

terminating the reception of the N second fingerprint images, and unlocking the terminal when the first fingerprint is matched; and

determining an application interface that is loaded and displayed the most in a preset time period during the matching the first fingerprint, and loading and displaying the application interface, wherein the preset time period comprises a current system time.

16. The method of claim 15 , further comprising:

when the first fingerprint is not matched, determining a target fingerprint image and matching the target fingerprint image, wherein the target fingerprint image is the best fingerprint image among the N second fingerprint images; and

unlocking the terminal when the target fingerprint image is matched.

17. The method of claim 15 , further comprising:

before receiving the first fingerprint image, determining whether the finger of the user is in the steady state, wherein determining whether the finger of the user is in the steady state comprises:

receiving at least two third fingerprint images; and

determining whether the finger of the user is in the steady state based on a difference in clarity of the at least two third fingerprint images.

18. The method of claim 15 , wherein the fingerprint recognition sensor comprises R sensing electrodes, and the method further comprises:

determining whether the finger of the user is in the steady state before receiving the first fingerprint image, wherein determining whether the finger of the user is in a steady state comprises:

receiving at least two sets of data via the R sensing electrodes of the fingerprint recognition sensor, wherein each set of the at least two sets of data comprises R capacitance values, and R is an integer greater than 1; and

determining whether the finger of the user is in the steady state based on differences in the R capacitance values between each of the at least two sets of data.