Systems and methods for image exposure

1. A method for high-dynamic range (HDR) imaging, comprising:

identifying one or more faces in a preview image;

identifying a region of interest (ROI) for each identified face of the one or more faces in the preview image, wherein a number of identified ROIs is more than one;

determining a number of images to be captured for an HDR image to be the number of identified ROIs; and

for each ROI corresponding to an identified face of the one or more faces:

determining a skin tone of the identified face;

determining, based on the determined skin tone and a comparison between the identified face and the ROI corresponding to the identified face, a target brightness of the respective image associated with the ROI; and

determining, based on the target brightness, an exposure value of the respective image associated with the ROI.

2. The method of claim 1 , wherein determining the exposure value of a respective image associated with a ROI comprises exclusively using the ROI in determining the exposure value.

3. The method of claim 2 , further comprising:

determining a separate exposure value from an entirety of the preview image, wherein the exposure value is to be used for capturing an image other than the number of images;

receiving the number of images and the image other than the number of images captured using corresponding exposure values; and

generating the HDR image based on the number of images and the image other than the number of images.

4. The method of claim 1 , further comprising:

receiving a user input for the preview image; and

identifying one or more ROIs of the preview image from the user input.

5. The method of claim 1 , further comprising for each ROI corresponding to an identified face of the one or more faces:

comparing a size of the identified face to a size of the ROI corresponding to the identified face.

6. A device configured to generate a High-Dynamic Range (HDR) image, comprising:

one or more processors implemented in circuitry; and

a memory coupled to the one or more processors and including instructions that, when executed by the one or more processors, cause the device to:

identify one or more faces in a preview image;

identify a region of interest (ROI) for each identified face of the one or more faces in the preview image, wherein a number of identified ROIs is more than one;

determine a number of images to be captured for an HDR image to be the number of identified ROIs; and

for each ROI corresponding to an identified face of the one or more faces:

determine a skin tone of the identified face;

determine, based on the determined skin tone and a comparison between the identified face and the ROI corresponding to the identified face, a target brightness of the respective image associated with the ROI; and

determine, based on the target brightness, an exposure value of the respective image associated with the ROI.

7. The device of claim 6 , wherein execution of the instructions further causes the device to exclusively use the ROI in determining the exposure value.

8. The device of claim 7 , wherein execution of the instructions further causes the device to:

determine a separate exposure value from an entirety of the preview image, wherein the exposure value is to be used for capturing an image other than the number of images;

receive the number of images and the image other than the number of images captured using corresponding exposure values; and

generate the HDR image based on the number of images and the image other than the number of images.

9. The device of claim 8 , further comprising one or more cameras, wherein execution of the instructions further causes the device to:

capture the preview image using at least one camera of the one or more cameras; and

capture the number of images and the image other than the number of images using at least one camera of the one or more cameras.

10. The device of claim 6 , further comprising:

a display to display the preview image; and

a user interface to receive a user input for the displayed preview image;

wherein execution of the instructions further causes the device to identify one or more ROIs of the preview image from the user input.

11. The device of claim 6 , wherein execution of the instructions, for each ROI corresponding to an identified face of the one or more faces, further causes the device to:

compare a size of the identified face to a size of the ROI corresponding to the identified face.

12. A non-transitory computer-readable medium storing one or more programs containing instructions that, when executed by one or more processors of a device, cause the device to:

identify one or more faces in a preview image;

identify a region of interest (ROI) for each identified face of the one or more faces in the preview image, wherein a number of ROIs is more than one;

determine a number of images to be captured for an HDR image to be the number of identified ROIs; and

for each ROI corresponding to an identified face of the one or more faces:

determine a skin tone of the identified face;

determine, based on the determined skin tone and a comparison between the identified face and the ROI corresponding to the identified face, a target brightness of the respective image associated with the ROI; and

determine, based on the target brightness, an exposure value of the respective image associated with the ROI.

13. The non-transitory computer-readable medium of claim 12 , wherein execution of the instructions further causes the device to exclusively use the ROI of the preview image in determining the exposure value.

14. The non-transitory computer-readable medium of claim 13 , wherein execution of the instructions further causes the device to:

determine a separate exposure value from an entirety of the preview image, wherein the exposure value is to be used for capturing an image other than the number of images;

receive the number of images and the image other than the number of images captured using corresponding exposure values; and

generate the HDR image based on the number of images and the image other than the number of images.

15. The non-transitory computer-readable medium of claim 12 , wherein execution of the instructions further causes the device to:

receive a user input for the preview image; and

identify one or more ROIs of the preview image from the user input.

16. The non-transitory computer-readable medium of claim 12 , wherein execution of the instructions further causes the device to:

for each ROI corresponding to an identified face of the one or more faces, compare a size of the identified face to a size of the ROI corresponding to the identified face.