SYSTEM AND METHOD FOR GENERATING A DIGITAL IMAGE
The system includes instructions to cause a strobe unit to emit illumination during a first time interval according to a first set of strobe parameters, and to cause a camera module to sample a first image of the photographic scene during the first time interval according to a first set of exposure parameters. The first image is stored within an image set. The instructions cause the strobe unit to emit illumination during a second time interval according to a second set of strobe parameters, and to cause the camera module to sample a second image of the photographic scene during the second time interval based on a second set of exposure parameters. The second image is stored within the image set. An image is selected from the image set, and a resulting image is generated. The resulting image is stored in the image set.
1 . A mobile device, comprising:
a camera module, comprising an image sensor and configured to sample a photographic scene according to a set of exposure parameters comprising an exposure time and an exposure sensitivity;
a strobe unit, configured to illuminate the photographic scene according to a set of strobe parameters comprising a strobe intensity and a strobe color;
a display device, configured to generate a display of a digital image;
a touch-input device, configured to receive touch gestures;
a nonvolatile memory circuit; and
one or more processors in communication with the camera module and the strobe unit, wherein the one or more processors execute instructions to:
cause the strobe unit to emit illumination during a first time interval according to a first set of strobe parameters comprising a first strobe intensity and a first strobe color;
cause the camera module to sample a first image of the photographic scene during the first time interval according to a first set of exposure parameters;
store the first image within an image set;
cause the strobe unit to emit illumination during a second time interval according to a second set of strobe parameters comprising a second strobe intensity and a second strobe color, wherein the second strobe intensity is non-zero and different than the first strobe intensity;
cause the camera module to sample a second image of the photographic scene during a second time interval based on a second set of exposure parameters;
store the second image within the image set;
cause the strobe unit to emit illumination during a third time interval according to a third set of strobe parameters comprising a third strobe intensity and a third strobe color, wherein the third strobe intensity is non-zero and different than the first strobe intensity;
cause the camera module to sample a third image of the photographic scene during a third time interval based on a third set of exposure parameters;
store the third image within the image set;
cause the strobe unit to be disabled from emitting illumination during a fourth time interval;
cause the camera module to sample a fourth image of the photographic scene during the fourth time interval based on a fourth set of exposure parameters;
store the fourth image within the image set;
select a flash image from the first image, the second image, and the third image within the image set;
generate a combined image by combining the flash image and the ambient image;
generate a resulting image by performing a white-balance correction on the combined image; and
store the resulting image in the image set.
2 . The mobile device of claim 1 , wherein the first strobe intensity is non-zero.
3 . The mobile device of claim 1 , wherein the second strobe intensity is the same as the third strobe intensity.
4 . The mobile device of claim 1 , wherein the first strobe color is equal to a measured ambient illumination color.
5 . The mobile device of claim 4 , wherein the first strobe color, the second strobe color, and the third strobe color are equal.
6 . The mobile device of claim 4 , wherein the measured ambient illumination color corresponds to color statistics accumulated while the one or more processors receive image data from the camera module.
7 . The mobile device of claim 1 , wherein the first set of exposure parameters is determined based on ambient illumination.
8 . The mobile device of claim 7 , wherein the first set of exposure parameters, the second set of exposure parameters, and the third set of exposure parameters are equal.
9 . The mobile device of claim 1 , wherein the one or more processors further execute instructions to display, on the display device, the resulting image.
10 . The mobile device of claim 9 , wherein the one or more processors further execute instructions to:
display, on the display device, a user interface slider control;
receive, from the touch-input device, a slide gesture directed to the slider control; and
in response to receiving the slide gesture, select and display the first image on the display device.
11 . The mobile device of claim 1 , wherein selecting an image from the image set comprises evaluating exposure quality metric values for the images and selecting the image with the best exposure quality metric value.
12 . The mobile device of claim 11 , wherein the quality metric value comprises a cost function value, and the best exposure quality metric value corresponds to the lowest cost function value.
13 . The mobile device of claim 12 , wherein the cost function assigns a cost penalty to over-exposed pixels.
14 . The mobile device of claim 1 , wherein the instructions and the image set are stored in the nonvolatile memory circuit.
15 . The mobile device of claim 1 , wherein the first strobe color, the second strobe color, and the third strobe color are equal to a measured ambient illumination color, and wherein the first set of exposure parameters and the fourth set of exposure parameters are determined based on ambient illumination.