Image signal processing for reducing lens flare

1. A non-transitory computer-readable storage medium, comprising executable instructions that, when executed by a processor, facilitate performance of operations, comprising:

obtaining a first input frame captured by a first image capture device of an image capture apparatus, the first image capture device having a first field-of-view, and the first input frame including lens flare corresponding to a primary light source;

obtaining a second input frame captured by a second image capture device of the image capture apparatus, the second image capture device having a second field-of-view partially overlapping the first field-of-view;

obtaining primary light source information corresponding to the primary light source based on the first input frame and the second input frame, wherein the primary light source information comprises a flare model;

obtaining a dark corner profile based on a relative illumination of an area outside a first image circle of the first input frame and a second image circle of the second input frame;

obtaining a flare mask based on a flare difference estimation along a stitch line between the first input frame and the second input frame; and

obtaining a processed frame by modifying the first input frame based on the primary light source information to minimize the lens flare, wherein modifying the first input frame comprises:

applying the flare model to the first input frame based on the primary light source information; and

subtracting the flare mask; and

outputting the processed frame.

2. The non-transitory computer-readable storage medium of claim 1 , wherein modifying the first input frame to minimize the lens flare includes modifying the first input frame to minimize a diffuse lens flare corresponding to the primary light source.

3. The non-transitory computer-readable storage medium of claim 2 , wherein the second input frame omits the diffuse lens flare.

4. The non-transitory computer-readable storage medium of claim 1 , wherein modifying the first input frame to minimize the lens flare includes modifying the first input frame to minimize a lens flare artifact.

5. The non-transitory computer-readable storage medium of claim 1 , wherein obtaining the primary light source information includes obtaining a difference between a first portion of the first input frame and a second portion of the second input frame.

6. The non-transitory computer-readable storage medium of claim 5 , wherein obtaining the difference between the first portion of the first input frame and the second portion of the second input frame includes:

obtaining a first value of a first pixel from the first portion of the first input frame;

obtaining a second value of a second pixel from the second portion of the second input frame, wherein the first pixel is spatially aligned with the second pixel according to a predicted alignment; and

obtaining a difference between the first pixel and the second pixel.

7. The non-transitory computer-readable storage medium of claim 5 , wherein obtaining the primary light source information includes:

obtaining the primary light source information by evaluating the flare model based on the difference between the first portion of the first input frame and the second portion of the second input frame.

8. The non-transitory computer-readable storage medium of claim 1 , wherein obtaining the primary light source information includes obtaining primary light source orientation information and obtaining primary light source brightness information, and wherein applying the flare model to the first input frame based on the primary light source information includes applying the flare model to the first input frame based on the primary light source orientation information and the primary light source brightness information.

9. The non-transitory computer-readable storage medium of claim 1 , wherein obtaining the processed frame includes:

generating a combined frame based on the processed frame and the second input frame; and

using the combined frame as the processed frame.

10. The non-transitory computer-readable storage medium of claim 1 , wherein the primary light source is the sun.

11. The non-transitory computer-readable storage medium of claim 1 , wherein obtaining the processed frame by modifying the first input frame further comprising:

diffusing the flare mask towards a center of the first input frame.

12. A method comprising:

obtaining a first input frame captured by a first image capture device of an image capture apparatus, the first image capture device having a first field-of-view, and the first input frame including lens flare corresponding to a primary light source, wherein the first input frame includes a first image circle based on the first field-of-view;

obtaining a second input frame captured by a second image capture device of the image capture apparatus, the second image capture device having a second field-of-view partially overlapping the first field-of-view, wherein the second input frame includes a second image circle based on the second field-of-view;

obtaining primary light source information corresponding to the primary light source based on the first input frame and the second input frame;

obtaining a dark corner profile based on a relative illumination of an area outside the first image circle and the second image circle;

obtaining an intensity difference between the primary light source information and the dark corner profile;

obtaining a flare model;

obtaining a flare mask based on a flare difference estimation along a stitch line between the first input frame and the second input frame;

obtaining a processed frame by modifying the first input frame based on the primary light source information to minimize the lens flare, wherein modifying the first input frame includes applying the flare model to the first input frame based on the primary light source information and subtracting the flare mask; and

outputting the processed frame.

13. The method of claim 12 , wherein obtaining the flare model includes:

obtaining a difference of intensities along the stitch line between the first input frame and the second input frame; and

combining the difference of intensities with the dark corner profile.

14. The method of claim 12 , further comprising:

mapping the flare mask onto each image circle; and

diffusing the flare mask towards a respective center of each image.

15. An apparatus comprising:

an image processor, the image processor configured to:

obtain a first input frame captured by a first image capture device of the apparatus, the first image capture device having a first field-of-view, and the first input frame including lens flare corresponding to a primary light source;

obtain a second input frame captured by a second image capture device of the apparatus, the second image capture device having a second field-of-view partially overlapping the first field-of-view;

obtain primary light source information corresponding to the primary light source based on the first input frame and the second input frame, wherein, to obtain the primary light source information, the image processor is configured to:

obtain a first value of a first pixel from a first portion of the first input frame;

obtain a second value of a second pixel from a second portion of the second input frame, wherein the first pixel is spatially aligned with the second pixel according to a predicted alignment;

obtain a difference between the first pixel and the second pixel; and

include, in the primary light source information, a result of evaluating a flare model based on the difference;

obtain a processed frame, wherein:

to obtain the processed frame, the image processor is configured to:

obtain a dark corner profile based on a relative illumination of an area outside a first image circle of the first input frame and a second image circle of the second input frame;

obtain a flare mask based on a flare difference estimation along a stitch line between the first input frame and the second input frame; and

modify the first input frame based on the primary light source information to minimize the lens flare, wherein to modify the first input frame comprises to:

 apply the flare model to the first input frame based on the primary light source information; and

 subtract the flare mask; and

output the processed frame.

16. The apparatus of claim 15 , wherein the image processor is further configured to:

obtain an intensity difference between the primary light source information and the dark corner profile.

17. The apparatus of claim 16 , wherein the image processor is further configured to:

obtain a difference of intensities along the stitch line between the first input frame and the second input frame; and

combine the difference of intensities with the dark corner profile.

18. The apparatus of claim 16 , wherein the image processor is further configured to:

map the flare mask onto each image circle; and

diffuse the flare mask towards a center of each image.

19. The apparatus of claim 18 ,

wherein to diffuse the flare mask comprises to:

diffuse, for each color channel, the flare mask towards a center of each image.