Facebook Patent | Three-dimensional, 360-degree virtual reality exposure control

Patent: Three-dimensional, 360-degree virtual reality exposure control

Publication Number: 10200624

Publication Date: 2019-02-05

Applicants: Facebook

Abstract:

A camera system is configured to capture, via a plurality of cameras, 360 degree image information of a local area, at least a portion of which is in stereo. The camera system determines respective exposure settings for the plurality of cameras. A minimum shutter speed and a maximum shutter speed are determined from the determined exposure settings. A set of test exposure settings is determined using the determined minimum shutter speed and maximum shutter speed. A set of test images is captured using the plurality of cameras at each test exposure setting in the set of test exposure settings. Each set of test images includes images from each of the plurality of cameras that are captured using a same respective test exposure setting. A global exposure setting is selected based on the captured sets of test images. The selected global exposure setting is applied to the plurality of cameras.

Background:

The disclosure relates generally to camera imaging, and more specifically to exposure control of a three-dimensional (3D), 360-degree camera system.

Virtual reality systems capture images and/or video of an environment with one or more cameras. The images and/or video captured by the cameras are reconstructed to create a virtual reality that a user can interact with. The configuration of the one or more cameras impacts the quality of the images captured and the ability to reconstruct the images for a seamless virtual reality experience. Hence, the configuration of the cameras and lower quality captured images can adversely affect a user’s virtual reality experience.

Conventional 360 degree cameras operate by stitching a plurality of frames together into a single 360 degree frame. Each frame may be subject to different lighting conditions which can result in different exposure settings (e.g., aperture, shutter speed, film speed, gain, etc.) for one or more of the frames. The differences in exposure settings may result in an inferior 360-degree image generated using the frames having different exposure settings. For example, brightness of the 360-degree image may vary between portions associated with different frames, differences in shutter speed may cause moving objects to blur in some portions of the image, differences in aperture may cause depth of field to vary in the 360-degree image, and differences in gain may cause some portions of the 360-degree image to have excessive noise.

Summary:

A camera system is configured to capture, via a plurality of cameras, image information (e.g., image, video, etc.) across 360 degrees of a local area, at least a portion of which is in stereo. The camera assembly sends the image information to a processing server, which generates 3D-360 degree content of the local area from the image information. The 3D-360 degree content is media content associated with a 360-degree field of view of the camera assembly and which may be rendered in 3D, e.g., an image, a video, audio information, or some combination thereof.

To facilitate generation of high quality, natural looking 3D-360 degree content, the camera system uses a global exposure setting and a global shutter setting. For example, in some embodiments, the camera system triggers the plurality of cameras using a global shutter such that each camera captures image information at a same time. The camera system also applies a global exposure setting to each of plurality of cameras. A global exposure setting is a single exposure setting that is applied to all of the cameras in the camera system. The global shutter setting facilitates generation of natural looking 3D-360 degree content.

The camera system determines a global exposure setting using test images captured by the plurality of cameras. The camera system determines respective exposure settings for the plurality of cameras each having a respective field of view of a portion of a local area, and a combined field of view spans 360 degrees of the local area. As each of the cameras has a different field of view, it may have an exposure setting different than other cameras in the plurality of cameras. A minimum shutter speed and a maximum shutter speed are determined from the determined exposure settings. A set of test exposure settings are determined using the determined minimum shutter speed and maximum shutter speed. The camera system determines a set of test exposure settings using the determined minimum shutter speed and maximum shutter speed. The camera system captures a set of test images using the plurality of cameras at each test exposure setting in the set. Each set of test images includes images from each of the plurality of cameras that are captured using a same respective test exposure setting. The global exposure setting is selected based on the captured groups of test images. The selected global exposure setting is applied to the plurality of cameras.

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