System, method, and computer program for capturing a flash image based on ambient and flash metering
A system and method are provided for capturing a flash image based on ambient and flash metering. In use, a first ambient condition is metered for a first ambient frame. Next, a first ambient capture time is determined based on the metering of the first ambient condition. Further, a first flash condition is metered for a first flash frame, and a first flash capture time is determined based on the metering of the first flash condition. Next, a first ambient frame is captured based on the first ambient capture time. After capturing the first ambient frame, a flash circuit is enabled during an active period and, a first flash frame is captured based on a combination of the first ambient capture time and the first flash capture time. Finally, a final image is generated based on the first ambient frame and the first flash frame.
1. An apparatus, comprising:
a non-transitory memory storing instructions; and
one or more processors in communication with the non-transitory memory, wherein the one or more processors execute the instructions to:
meter a first ambient condition, using a camera module, for a first ambient frame;
determine a first ambient capture time based on the metering of the first ambient condition;
based on the first ambient capture time, determine that a need exists for pre-metering of a first flash condition;
meter the first flash condition, using the camera module, for a first flash frame, wherein metering the first flash condition includes a repetitive pre-metering operation where each sample of the repetitive pre-metering operation occurs at a different flash intensity level;
determine a first flash capture time based on the metering of the first flash condition;
capture, using a rolling shutter image sensor within the camera module, the first ambient frame based on the first ambient capture time;
after capturing the first ambient frame, enable a flash circuit during an active period;
capture, using the rolling shutter image sensor, the first flash frame based on a combination of the first ambient capture time and the first flash capture time;
perform a line reset after the combination of the first ambient capture time and the first flash capture time; and
generate a final image based on the first ambient frame and the first flash frame.
2. The apparatus of claim 1 , wherein metering the first ambient condition includes identifying a white balance.
3. The apparatus of claim 1 , wherein metering the first flash condition includes capturing multiple metering images.
4. The apparatus of claim 1 , wherein metering the first ambient condition results in a first set of exposure parameters and metering the first flash condition results in a second set of exposure parameters.
5. The apparatus of claim 1 , wherein an exposure time of the first flash condition is less than an exposure time of the first ambient condition.
6. The apparatus of claim 1 , wherein metering the first flash condition includes determining one or more of: a flash duration, a flash intensity, and a flash color.
7. The apparatus of claim 1 , comprising further instructions to:
capture a second image based on the first ambient capture time;
capture a third image based on the first flash capture time;
blend the second image and the third image to create a fourth image.
8. The apparatus of claim 1 , wherein metering the first flash condition includes determining exposure parameters that satisfy an exposure goal.
9. The apparatus of claim 8 , wherein the exposure goal ensures that not more than five percent of over-exposed pixels are contained within the final image.
10. The apparatus of claim 8 , wherein the exposure goal provides a limit on a number of over-exposed pixels within the final image.
11. The apparatus of claim 8 , wherein the exposure goal includes a set intensity goal including a range of goal values or a fixed goal value.
12. The apparatus of claim 8 , wherein the exposure goal bounds over-exposed pixels associated with the metering of the first flash condition to over-exposed pixels associated with the metering of the first ambient condition.
13. The apparatus of claim 8 , wherein the exposure goal is associated with a point of interest.
14. The apparatus of claim 1 , wherein the first flash condition is used to determine a flash intensity.
15. The apparatus of claim 14 , wherein the flash intensity is used to control over-exposed pixels or is used to satisfy an exposure goal.
16. The apparatus of claim 14 , wherein the flash intensity is based on the metering of the first ambient condition and a distance to a flash point of interest.
17. The apparatus of claim 1 , wherein the active period ends before a scan out of the first flash frame.
18. An apparatus, comprising:
a non-transitory memory storing instructions; and
one or more processors in communication with the non-transitory memory, wherein the one or more processors execute the instructions to:
meter a first ambient condition, using a camera module, for a first ambient frame;
determine a first ambient capture time based on the metering of the first ambient condition;
based on the first ambient capture time, determine that a need exists for pre-metering of a first flash condition;
meter the first flash condition, using the camera module, for a first flash frame, wherein metering the first flash condition includes a repetitive pre-metering operation where each sample of the repetitive pre-metering operation occurs at a different flash intensity level;
determine a first flash capture time based on the metering of the first flash condition;
capture, using a rolling shutter image sensor within the camera module, the first ambient frame based on the first ambient capture time;
after capturing the first ambient frame, enable a flash circuit during an active period;
capture, using the rolling shutter image sensor, the first flash frame based on a combination of the first ambient capture time and the first flash capture time;
perform a line reset after the combination of the first ambient capture time and the first flash capture time; and
generate a final image based on the first ambient frame and the first flash frame.
19. A method, comprising:
metering a first ambient condition, using a camera module, for a first ambient frame;
determining a first ambient capture time based on the metering of the first ambient condition;
based on the first ambient capture time, determine that a need exists for pre-metering of a first flash condition;
metering the first flash condition, using the camera module, for a first flash frame, wherein metering the first flash condition includes a repetitive pre-metering operation where each sample of the repetitive pre-metering operation occurs at a different flash intensity level;
determining a first flash capture time based on the metering of the first flash condition;
capturing, using a rolling shutter image sensor within the camera module, the first ambient frame based on the first ambient capture time;
after capturing the first ambient frame, enabling a flash circuit during an active period;
capturing, using the rolling shutter image sensor, the first flash frame based on a combination of the first ambient capture time and the first flash capture time;
performing a line reset after the combination of the first ambient capture time and the first flash capture time; and
generating a final image based on the first ambient frame and the first flash frame.