Panoramic camera with multiple image sensors using timed shutters
The present invention relates to the field of panoramic still and motion photography. In a first embodiment, a camera apparatus for panoramic photography includes a first image sensor positioned to capture a first image. The first image sensor has a rolling-shutter readout arranged in portrait orientation. The camera apparatus also includes second image sensor positioned to capture a second image. The second image sensor has a rolling-shutter readout arranged in portrait orientation. Finally, the camera apparatus includes a controller configured to signal the second image sensor to start capturing the second image before the first image sensor finishes capturing the first image. At least a portion of the first image is in front of the second image relative to a forward direction of the camera apparatus.
1. A method of capturing images to reduce parallax between a first image and a second image caused by movement of a camera apparatus, the method comprising:
moving the camera apparatus, the camera apparatus including a first camera and a second camera;
while moving the camera apparatus, starting to expose the first image using the first camera at a time T 1 using the first camera;
while moving the camera apparatus, starting to expose the second image using the second camera at a time T 2 , wherein T 2 is after T 1 ;
while moving the camera apparatus, completing exposure of the first image at a time T 3 after the time T 2 such that the first image and the second image include overlapping fields of view captured by the camera apparatus between the times T 2 and T 3 in order to reduce parallax between the first image and the second image.
2. The method of claim 1 , wherein the first camera includes a first image sensor and the second camera includes a second image sensor and different portions of the first and second image sensors are exposed at different times in order to capture the first and second images.
3. The method of claim 1 , wherein the first camera includes a set of photodiode columns, and starting to capture the first image includes starting to expose a first column of the set of photodiode columns of the first camera prior to starting the capture the second image, and completing exposure of the first image includes completing exposure of all columns of the set of photodiode columns of the first camera.
4. The method of claim 3 , wherein the second camera apparatus includes a set of photodiode columns, and starting to capture the second image includes starting to expose a first column of the set of photodiode columns of the second camera after exposing the first column of the set of photodiode columns but prior to completing exposure of all columns of the set of photodiode columns of the first camera.
5. The method of claim 3 , wherein moving the camera apparatus includes moving the camera apparatus in a first direction, and wherein the first column of the set of photodiode columns of the first camera is a forward most column of the set of photodiode columns of the first camera relative to the first direction.
6. The method of claim 5 , wherein completing exposure of the first image includes completing exposure of a back most column of the set of photodiode columns of the first camera relative to the first direction.
7. The method of claim 3 , wherein the set of photodiode columns are arranged in a portrait orientation relative to a ground surface.
8. The method of claim 1 , further comprising completing exposure of the first image in order to reduce a likelihood that an object in the overlapping field of view has moved between the times T 2 and T 3 .
9. The method of claim 1 , further comprising completing exposure of the second image at a time T 4 after the time T 3 .
10. The method of claim 1 , wherein moving the camera apparatus includes moving the camera apparatus at a given speed, and the method further comprises, prior to starting to expose the second image, determining the time T 2 based on the given speed.
11. The method of claim 10 , wherein the given speed is an average speed of the movement of the camera apparatus while the first and second images are being exposed.
12. The method of claim 11 , wherein determining the time T 2 is further based on a distance between entrance pupils of the first and second cameras.
13. The method of claim 1 , wherein the camera apparatus includes a set of cameras including the first and second cameras, and the method further comprising, while moving the camera apparatus, capturing additional images using the set of cameras where each additional image has an overlapping field of view with at least one other of the additional images.
14. The method of claim 1 , wherein a difference in time between T 2 and T 3 is proportionate to a size of the overlapping fields of view.