Processing of extended dimension light field images
In one embodiment, methods, media, and systems process and display light field images using a view function that is based on pixel locations in the image and on the viewer's distance (observer's Z position) from the display. The view function can be an angular view function that specifies different angular views for different pixels in the light field image based on the inputs that can include: the x or y pixel location in the image, the viewer's distance from the display, and the viewer's angle relative to the display. In one embodiment, light field metadata, such as angular range metadata and/or angular offset metadata can be used to process and display the image. In one embodiment, color volume mapping metadata can be used to adjust color volume mapping based on the determined angular views; and the color volume mapping metadata can also be adjusted based on angular offset metadata.
1. A method for processing data, the method comprising:
receiving image data represented in a light field format that includes image data for different views of an image for each pixel in a plurality of pixels in the image;
receiving angular range metadata and angular offset metadata for the image, wherein the angular range metadata specifies a range of angles over which the image can be accurately viewed and the angular offset metadata is used to adjust a color volume mapping;
receiving a selection of a desired viewpoint relative to the image; and
determining one or more views at each pixel in the plurality of pixels using a view function that determines the one or more views, the view function having inputs comprising:
spatial coordinates of each pixel in the plurality of pixels in the image, the angular range metadata, the desired viewpoint, and a distance between the desired viewpoint and a display.
2. The method as in claim 1 , wherein the view function is an angular view function that comprises a horizontal angular view function and a vertical angular view function; the horizontal angular view function having inputs comprising: the distance between the desired viewpoint and the display, a horizontal spatial coordinate for a pixel, and a horizontal component of the desired viewpoint; the vertical angular view function having inputs comprising: the distance between the desired viewpoint and the display, a vertical spatial coordinate for a pixel, and a vertical component of the desired viewpoint.
3. The method as in claim 1 , wherein the view function is defined relative to a reference plane at a reference distance from the display, and wherein the view function will determine the same view for all pixels in the image for any one viewpoint in the reference plane.
4. The method as in claim 3 , wherein for a viewpoint outside of the reference plane, the view function determines different views for different pixels in the image, and wherein the desired viewpoint is selected based on an estimated viewer position or a user selection of the desired viewpoint.
5. The method according to claim 1 , wherein the method further comprises:
rendering, based on the determined one or more views, the image; and
displaying the rendered image at the determined view.
6. The method according to claim 1 , wherein the image is a 4D light field image that has been previously rendered as volumetric content that is stored in either a) a decoded planar format as tiles, each tile being one of the possible views or b) an interleaved format.
7. The method according to claim 1 , wherein the method further comprises:
receiving color volume mapping metadata;
applying color volume mapping based on the determined one or more views and the color volume mapping metadata.
8. The method as in claim 7 , wherein the color volume mapping metadata is adjusted based on the desired viewpoint and the angular offset metadata which specifies one or more adjustments to the color volume mapping metadata based on, or as a function of, the desired viewpoint.
9. The method as in claim 8 , wherein the method further comprises:
interpolating the angular offset metadata based on the desired viewpoint.
10. The method according to claim 7 , wherein the color volume mapping metadata varies over a plurality of different images on a scene by scene basis or an image by image basis.
11. The method according to claim 1 , wherein the method further comprises:
interpolating the determined one or more views, at the desired viewpoint, from a set of nearest available views in the image data.
12. The method as in claim 11 , wherein the interpolating uses bilinear interpolation from a dense light field image that has sufficient angular density.
13. The method according to claim 1 , wherein the method further comprises:
limiting viewpoints to a valid viewing zone, and wherein a valid viewing zone of an image is defined by the angular range metadata.
14. The method as in claim 13 , wherein the limiting comprises one of (a) hard clamping an invalid viewpoint to a viewpoint in the valid viewing zone or (b) soft clamping the invalid viewpoint to a viewpoint in the valid viewing zone, wherein a hard clamping always selects a point on a border of the valid viewing zone and a soft clamping selects a set of points near, but not on, the border of the valid viewing zone.
15. The method of claim 1 , further comprising:
receiving metadata that includes offset metadata related to luminance metadata that specifies a statistical luminance value of the image, the offset metadata specifying an adjustment of the luminance metadata as a function of the viewpoint.
16. The method as in claim 1 , wherein the image is a 4D light field image that has been previously rendered as volumetric content, and wherein the selection of the desired viewpoint is received from a user in order to see the image at the desired viewpoint.
17. A data processing system programmed or configured to perform a method as in claim 1 .
18. A non-transitory machine readable medium storing executable program instructions which when executed by a data processing system cause the data processing system to perform a method as in claim 1 .