Exposure control method and device, and electronic device

1. A method for exposure control, comprising:

determining a first exposure compensation value based on a shake degree of an imaging device according to a mapping relationship between the shake degree of the imaging device and an exposure compensation value;

determining a second exposure compensation value by adjusting the first exposure compensation value depending on a decision of whether a face is contained in a preview of an image to be captured, wherein the second exposure compensation value when a face is contained is lower than the second exposure compensation value when no face is contained;

determining a target exposure for an image to be captured based on a base exposure and the second exposure compensation value;

determining an exposure time for the image to be captured based on the target exposure and a photo-sensibility for the image to be captured;

in response to determining that the exposure time for the image to be captured is greater than an upper limit, updating the exposure time for the image to be captured based on the upper limit; and

performing an exposure control based on the exposure time and the photo-sensibility for the image to be captured.

2. The method of claim 1 , further comprising:

determining, based on a shake degree, the photo-sensibility for the image to be captured and the upper limit.

3. The method of claim 2 , wherein determining, based on the shake degree, the photo-sensibility for the image to be captured and the upper limit comprises:

obtaining displacement information collected by a sensor arranged on an imaging device;

determining the shake degree of the imaging device based on the displacement information;

in response to determining that the shake degree is greater than or equal to a shake threshold, determining that the photo-sensibility equals to a first photo-sensibility value and determining that the upper limit equals to a first time value; and

in response to determining that the shake degree is less than the shake threshold, determining that the photo-sensibility equals to a second photo-sensibility value and determining that the upper limit equals to a second time value, the first photo-sensibility value being greater than the second photo-sensibility value, and the first time value being less than the second time value.

4. The method of claim 3 , wherein,

the first photo-sensibility value is a multiple of the second photo-sensibility value, the multiple is greater than or equal to 2; and

the second photo-sensibility value is a minimum photo-sensibility of the imaging device.

5. The method of claim 3 , wherein the first time value and the second time value are determined based on the ambient light luminance;

the first time value ranges from 150 milliseconds to 300 milliseconds; and

the second time value ranges from 4.5 seconds to 5.5 seconds.

6. The method of claim 1 , further comprising:

determining whether a current capturing scene is a night scene, based on the preview of the image to be captured; and

in response to determining that the current capturing scene is the night scene, identifying a night mode suitable for the current capturing scene, based on the shake degree or the decision whether a face is contained in the preview of the image to be captured.

7. The method of claim 6 , wherein determining whether the current capturing scene is the night scene, based on the preview of the image to be captured comprises:

determining the current capturing scene is the night scene in response to determining that a brightness distribution of the preview of the image to be captured satisfies a preset brightness distribution corresponding to the night scene.

8. The method of claim 1 , further comprising:

in response to determining that the exposure time of the image to be captured is less than a lower limit, updating the photo-sensibility for the image to be captured based on the target exposure and the lower limit, and updating the exposure time for the image to be captured based on the lower limit.

9. A non-transitory computer readable storage medium having a computer executable instruction, wherein when the computer executable instruction is executed by one or more processors, the one or more processors are configured to execute an exposure control method, wherein the exposure control method comprises:

determining a first exposure compensation value based on a shake degree of an imaging device according to a mapping relationship between the shake degree of the imaging device and an exposure compensation value;

determining a second exposure compensation value by adjusting the first exposure compensation value depending on a decision of whether a face is contained in a preview of an image to be captured, wherein the second exposure compensation value when a face is contained is lower than the second exposure compensation value when no face is contained;

determining a target exposure for an image to be captured based on a base exposure and the second exposure compensation value;

determining an exposure time for the image to be captured based on the target exposure and a photo-sensibility for the image to be captured;

in response to determining that the exposure time for the image to be captured is greater than an upper limit, updating the exposure time for the image to be captured based on the upper limit; and

performing an exposure control based on the exposure time and the photo-sensibility for the image to be captured.

10. An electronic device, comprising a memory and a processor, wherein the memory is configured to store a computer readable instruction, when the computer readable instruction is executed by a processor, the processor is configured to:

determine a first exposure compensation value based on a shake degree of an imaging device according to a mapping relationship between the shake degree of the imaging device and an exposure compensation value;

determine a second exposure compensation value by adjusting the first exposure compensation value depending on a decision of whether a face is contained in a preview of an image to be captured, wherein the second exposure compensation value when a face is contained is lower than the second exposure compensation value when no face is contained;

determine a target exposure for an image to be captured based on a base exposure and the second exposure compensation value;

determine an exposure time for the image to be captured based on the target exposure and a photo-sensibility for the image to be captured;

in response to determining that the exposure time for the image to be captured is greater than an upper limit, update the exposure time for the image to be captured based on the upper limit; and

perform an exposure control based on the exposure time and the photo-sensibility for the image to be captured.

11. The electronic device of claim 10 , wherein the processor is further configured to:

determine, based on a shake degree, the photo-sensibility for the image to be captured and the upper limit.

12. The electronic device of claim 11 , wherein the processor is configured to determine, based on the shake degree, the photo-sensibility and the upper limit by:

obtaining displacement information collected by a sensor arranged on an imaging device;

determining the shake degree of the imaging device based on the displacement information;

in response to determining that the shake degree is greater than or equal to a shake threshold, determining that the photo-sensibility equals to a first photo-sensibility value and determining that the upper limit equals to a first time value; and

in response to determining that the shake degree is less than the shake threshold, determining that the photo-sensibility equals to a second photo-sensibility value and determining that the upper limit equals to a second time value, the first photo-sensibility value being greater than the second photo-sensibility value, and the first time value being less than the second time value.

13. The electronic device of claim 12 , wherein,

the first photo-sensibility value is a multiple of the second photo-sensibility value, the multiple is greater than or equal to 2; and

the second photo-sensibility value is a minimum photo-sensibility of the imaging device.

14. The electronic device of claim 12 , wherein the first time value and the second time value are determined based on the ambient light luminance;

the first time value ranges from 150 milliseconds to 300 milliseconds; and

the second time value ranges from 4.5 seconds to 5.5 seconds.

15. The electronic device of claim 10 , wherein the processor is further configured to:

determine whether a current capturing scene is a night scene, based on the preview of the image to be captured; and

in response to determining that the current capturing scene is the night scene, identify a night mode suitable for the current capturing scene, based on the shake degree of an imaging device or the decision whether a face is contained in the preview of the image to be captured.

16. The electronic device of claim 15 , wherein the processor is configured to determine whether the current capturing scene is the night scene, based on the preview of the image to be captured by:

determining the current capturing scene is the night scene in response to determining that a brightness distribution of the preview of the image to be captured satisfies a preset brightness distribution corresponding to the night scene.

17. The electronic device of claim 10 , wherein the processor is further configured to:

in response to determining that the exposure time of the image to be captured is less than a lower limit, update the photo-sensibility for the image to be captured based on the target exposure for the image to be captured and the lower limit and update the exposure time for the image to be captured based on the lower limit.