Apple Patent | Packed Image Format for Multi-Directional Video
Publication Number: 20190007669
Publication Date: 2019-01-03
Frame packing techniques are disclosed for multi-directional images and video. According to an embodiment, a multi-directional source image is reformatted into a format in which image data from opposing fields of view are represented in respective regions of the packed image as flat image content. Image data from a multi-directional field of view of the source image between the opposing fields of view are represented in another region of the packed image as equirectangular image content. It is expected that use of the formatted frame will lead to coding efficiencies when the formatted image is processed by predictive video coding techniques and the like.
The present disclosure relates to coding techniques for omnidirectional and multi-directional images and videos.
Some modern imaging applications capture image data from multiple directions about a camera. Some cameras pivot during image capture, which allows a camera to capture image data across an angular sweep that expands the camera’s effective field of view. Some other cameras have multiple imaging systems that capture image data in several different fields of view. In either case, an aggregate image may be created that represents a merger or “stitching” of image data captured from these multiple views.
Many modern coding applications are not designed to process such omnidirectional or multi-directional image content. Such coding applications are designed based on an assumption that image data within an image is “flat,” that the image data represents a captured field of view in a planar projection. Thus, the coding applications do not account for image distortions that can arise when processing these omnidirectional or multi-directional images with the distortions contained within them. These distortions can cause ordinary video coders to fail to recognize redundancies in image content, which leads to inefficient coding.
Accordingly, the inventors perceive a need in the art for image formatting techniques that can lead to higher coding efficiencies when omnidirectional and multi-directional image content are coded for delivery to other devices.