Systems and methods for selecting a best facial image of a target human face

1. A system for selecting a best facial image of a target human face, comprising:

at least one storage medium including a set of instructions for selecting the facial image including the target human face; and

at least one processor in communication with the storage medium, wherein when executing the set of instructions, the at least one processor is directed to:

determine whether a candidate facial image is obtained before a time point in a time period threshold, wherein the candidate facial image has a greatest quality score of the target human face among a plurality of facial images of the target human face;

in response to a determination that the candidate facial image is obtained before the time point, determine the candidate facial image as the best facial image of the target human face;

in response to a determination that the candidate facial image is obtained after the time point, increase the time period threshold; and

operate a candidate facial image determining procedure; and

store the best facial image together with a face ID and the greatest quality score of the target human face in a face log, wherein to operate the candidate facial image determining procedure, the at least one processor is directed to:

obtain an image periodically from an image acquiring device;

for each image, obtain at least one human face from the image;

for each of the at least one human face in a current image,

determine a current quality score of the human face;

determine whether the human face is the target human face that has been stored in the face log;

in response to a determination that the human face is the target human face, obtain the stored facial image of the target human face and the stored greatest quality score thereof from the face log; and

select the candidate facial image from the stored facial image and the current image based on the current quality score and the stored quality score.

2. The system of claim 1 , wherein before determining whether the candidate facial image is obtained before the time point, the at least one processor is further directed to:

determine whether a detecting time period of the target human face is greater than the time period threshold; and

in response to a determination that the detecting time period is greater than the time period threshold, determine whether the candidate facial image is obtained before the time point.

3. The system of claim 2 , wherein the at least one processor is further directed to:

in response to a determination that the detecting time period is not greater than the time period threshold, operate a candidate facial image determining procedure.

4. The system of claim 1 , wherein the at least one processor is directed to:

in response to a determination that the human face is not the target human face, determine whether the human face is a newly-appeared human face; and

in response to a determination that the human face is the newly-appeared human face, store the newly-appeared human face in the face log together with the current quality score thereof and a new face ID.

5. The system of claim 1 , wherein to determine the current quality score of the human face, the at least one processor is further directed to:

obtain an angle score of the human face in the current image; and

obtain an angle weight of the human face.

6. The system of claim 5 , wherein the at least one processor is directed to:

obtain a clarity score of the human face in the current image; and

obtain a clarity weight of the human face.

7. The system of claim 6 , wherein the at least one processor is directed to:

obtain a size score of the human face in the current image; and

obtain a size weight of the human face.

8. The system of claim 7 , wherein the at least one processor is directed to:

determine the current quality score of the human face based on the angle score, the angle weight, the clarity score, the clarity weight, the size score, and the size weight.

9. A method for selecting a best facial image of a target human face, comprising:

determining whether a candidate facial image is obtained before a time point in a time period threshold, wherein the candidate facial image has a greatest quality score of the target human face among a plurality of facial images of the target human face;

in response to a determination that the candidate facial image is obtained before the time point, determining the candidate facial image as the best facial image of the target human face;

in response to a determination that the candidate facial image is obtained after the time point, increase the time period threshold; and

operate a candidate facial image determining procedure; and

storing the best facial image together with a face ID and the greatest quality score of the target human face in a face log, wherein to operate the candidate facial image determining procedure, the at least one processor is directed to:

obtain an image periodically from an image acquiring device;

for each image, obtain at least one human face from the image;

for each of the at least one human face in a current image,

determine a current quality score of the human face;

determine whether the human face is the target human face that has been stored in the face log;

in response to a determination that the human face is the target human face, obtain the stored facial image of the target human face and the stored greatest quality score thereof from the face log; and

select the candidate facial image from the stored facial image and the current image based on the current quality score and the stored quality score.

10. The method of claim 9 , wherein before determining whether the candidate facial image is obtained before the time point, the method further includes:

determining whether a detecting time period of the target human face is greater than the time period threshold; and

in response to a determination that the detecting time period is greater than the time period threshold, determining whether the candidate facial image is obtained before the time point.

11. The method of claim 10 further comprising:

in response to a determination that the detecting time period is not greater than the time period threshold, operating a candidate facial image determining procedure.

12. The method of claim 9 , further comprising:

in response to a determination that the human face is not the target human face, determining whether the human face is a newly-appeared human face; and

in response to a determination that the human face is the newly-appeared human face, storing the newly-appeared human face in the face log together with the current quality score thereof and a new face ID.

13. The method of claim 9 , wherein the determining the current quality score of the human face includes:

obtaining an angle score of the human face in the current image; and

obtaining an angle weight of the human face.

14. The method of claim 13 further comprising:

obtaining a clarity score of the human face in the current image; and

obtaining a clarity weight of the human face.

15. The method of claim 14 further comprising:

obtaining a size score of the human face in the current image;

obtaining a size weight of the human face; and

determining the current quality score of the human face based on the angle score, the angle weight, the clarity score, the clarity weight, the size score, and the size weight.

16. A non-transitory readable medium, comprising at least one set of instructions for selecting a best facial image of a target human face, wherein when executed by at least one processor of an electrical device, the at least one set of instructions directs the at least one processor to perform a method, the method comprising:

determining whether a candidate facial image is obtained before a time point in a time period threshold, wherein the candidate facial image has a greatest quality score of the target human face among a plurality of facial images of the target human face;

in response to a determination that the candidate facial image is obtained before the time point, determining the candidate facial image as the best facial image of the target human face;

in response to a determination that the candidate facial image is obtained after the time point, increase the time period threshold; and

operate a candidate facial image determining procedure; and

storing the best facial image together with a face ID and the greatest quality score of the target human face in a face log, wherein to operate the candidate facial image determining procedure, the at least one processor is directed to:

obtain an image periodically from an image acquiring device;

for each image, obtain at least one human face from the image;

for each of the at least one human face in a current image,

determine a current quality score of the human face;

determine whether the human face is the target human face that has been stored in the face log;

in response to a determination that the human face is the target human face, obtain the stored facial image of the target human face and the stored greatest quality score thereof from the face log; and

select the candidate facial image from the stored facial image and the current image based on the current quality score and the stored quality score.