Conversion between aspect ratios in camera
A camera system captures an image in a source aspect ratio and applies a transformation to the input image to scale and warp the image to generate an output image having a target aspect ratio different than the source aspect ratio. The output image has the same field of view as the input image, maintains image resolution, and limits distortion to levels that do not substantially affect the viewing experience. In one embodiment, the output image is non-linearly warped relative to the input image such that a distortion in the output image relative to the input image is greater in a corner region of the output image than a center region of the output image.
1. An image capture apparatus, comprising:
an image sensor configured to capture an input image having a source aspect ratio, the input image including pixels located at input positions defined along a first axis and a second axis, the first axis perpendicular to the second axis;
a display coupled to one or more physical processors; and
the one or more physical processors configured by machine-readable instructions to:
obtain the input image;
determine a portion within the input image, the portion including a subset of the pixels; and
apply a transformation to the input image to generate an output image, the output image having a target aspect ratio different than the source aspect ratio, the output image including the pixels located at output positions defined along the first axis and the second axis, wherein:
the transformation non-uniformly shifts the pixels from the input positions to the output positions based on (1) the input positions along the first axis, and (2) the input positions along the second axis; and
the transformation non-uniformly shifts the pixels such that differences between the input positions and the output positions of the subset of the pixels within the portion are less than differences between the input positions and the output positions of others of the pixels; and
present the output image on the display.
2. A system that converts between aspect ratios, the system comprising:
one or more physical processors configured by machine-readable instructions to:
obtain an input image, the input image having a source aspect ratio, the input image including pixels located at input positions defined along a first axis and a second axis, the first axis perpendicular to the second axis;
determine a portion within the input image, the portion including a subset of the pixels; and
apply a transformation to the input image to generate an output image, the output image having a target aspect ratio different than the source aspect ratio, the output image including the pixels located at output positions defined along the first axis and the second axis, wherein:
the transformation non-uniformly shifts the pixels from the input positions to the output positions based on (1) the input positions along the first axis, and (2) the input positions along the second axis; and
the transformation non-uniformly shifts the pixels such that differences between the input positions and the output positions of the subset of the pixels within the portion are less than differences between the input positions and the output positions of others of the pixels.
3. The system of claim 2 , wherein the transformation includes:
a scaling function to uniformly stretch or compress the input image along the first axis; and
a warping function to non-uniformly warp the input image along the second axis.
4. The system of claim 3 , wherein the scaling function and the warping function preserves the input positions of the subset of the pixels as the output positions of the subset of the pixels.
5. The system of claim 3 , wherein the scaling function changes the source aspect ratio to the target aspect ratio.
6. The system of claim 2 , wherein the one or more physical processors are included within a camera.
7. The system of claim 6 , wherein the output image is presented on a display of the camera.
8. The system of claim 2 , wherein the portion corresponds to a center portion of the input image.
9. The system of claim 2 , wherein the portion corresponds to a non-center portion of the input image.
10. The system of claim 2 , wherein the transformation non-uniformly shifts the pixels from the input positions to the output positions further based on distances between the input positions and the portion.
11. The system of claim 2 , wherein the one or more physical processors are further configured by machine-readable instructions to determine the portion based on a location of an object within the input image such that the portion includes the object.
12. The system of claim 2 , wherein the input image includes a video frame of a video.
13. A method for converting between aspect ratios, the method performed by a computing system including one or more physical processors, the method comprising:
obtaining, by the computing system, an input image, the input image having a source aspect ratio, the input image including pixels located at input positions defined along a first axis and a second axis, the first axis perpendicular to the second axis;
determining a portion within the input image, the portion including a subset of the pixels; and
applying, by the computing system, a transformation to the input image to generate an output image, the output image having a target aspect ratio different than the source aspect ratio, the output image including the pixels located at output positions defined along the first axis and the second axis, wherein:
the transformation non-uniformly shifts the pixels from the input positions to the output positions based on (1) the input positions along the first axis, and (2) the input positions along the second axis; and
the transformation non-uniformly shifts the pixels such that differences between the input positions and the output positions of the subset of the pixels within the portion are less than differences between the input positions and the output positions of others of the pixels.
14. The method of claim 13 , wherein the transformation includes:
a scaling function to uniformly stretch or compress the input image along the first axis; and
a warping function to non-uniformly warp the input image along the second axis.
15. The method of claim 14 , wherein the scaling function and the warping function preserves the input positions of the subset of the pixels as the output positions of the subset of the pixels.
16. The method of claim 13 , wherein the portion corresponds to a center portion of the input image.
17. The method of claim 13 , wherein the portion corresponds to a non-center portion of the input image.
18. The method of claim 13 , wherein the transformation non-uniformly shifts the pixels from the input positions to the output positions further based on distances between the input positions and the portion.
19. The method of claim 13 , further comprising determining the portion based on a location of an object within the input image such that the portion includes the object.
20. The method of claim 13 , wherein the input image includes a video frame of a video.