Systems and methods for encoding light field image files

• US 9,811,753 B2
• Filed: 03/24/2015
• Issued: 11/07/2017
• Est. Priority Date: 09/28/2011
• Status: Active Grant

• Current Assignee: FotoNation Limited (Adeia Inc.)
• Original Assignee: Fotonation Cayman Limited
• Inventors: Venkataraman, Kartik, Nisenzon, Semyon, Lelescu, Dan
• Primary Examiner(s): Dang, Duy M
• Application Number:
  US14/667,495
• Publication Number:
  US 20150199793A1
• Time in Patent Office: 959 Days
• CPC Class Codes: G06T 15/08 Volume rendering
• CPC Class Codes: G06T 2207/10052 Images from lightfield camera
• CPC Class Codes: G06T 3/4007 based on interpolation, e.g. bilinear interpolation image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403
• CPC Class Codes: G06T 3/4053 based on super-resolution, i.e. the output image resolution being higher than the sensor resolution
• CPC Class Codes: G06T 7/50 Depth or shape recovery
• CPC Class Codes: G06T 7/596 from three or more stereo images
• CPC Class Codes: G06T 9/00 Image coding bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00
• CPC Class Codes: G06T 9/20 Contour coding, e.g. using detection of edges
• CPC Class Codes: H04N 13/128 Adjusting depth or disparity
• CPC Class Codes: H04N 13/139 Format conversion, e.g. of frame-rate or size
• CPC Class Codes: H04N 13/161 Encoding, multiplexing or demultiplexing different image signal components for multi-view video sequence encoding H04N19/597
• CPC Class Codes: H04N 13/178 Metadata, e.g. disparity information
• CPC Class Codes: H04N 13/243 using three or more 2D image sensors
• CPC Class Codes: H04N 13/271 wherein the generated image signals comprise depth maps or disparity maps
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/597 specially adapted for multi-view video sequence encoding
• CPC Class Codes: H04N 19/625 using discrete cosine transform [DCT]
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/85 using pre-processing or post-processing specially adapted for video compression
• CPC Class Codes: H04N 2013/0081 : Depth or disparity estimation from stereoscopic image signals

Abstract

Systems and methods configured to store images synthesized from light field image data and metadata describing the images in electronic files and render images using the stored image and the metadata in accordance with embodiments of the invention are disclosed. One embodiment includes a processor and memory containing an encoding application and light field image data, where the light field image data comprises a plurality of low resolution images of a scene captured from different viewpoints. In addition, the encoding application configures the processor to synthesize a higher resolution image of the scene from a reference viewpoint using the low resolution images, where synthesizing the higher resolution image involves creating a depth map that specifies depths from the reference viewpoint for pixels in the higher resolution image; encode the higher resolution image; and create a light field image file including the encoded image and metadata including the depth map.

Claims

1. An image processing system, comprising:

a processor; and

memory containing an encoding application;

wherein the encoding application configures the processor to;

control capture of a plurality of images of a scene from different viewpoints by an array of cameras;

generate a depth map that specifies depths for pixels from a reference viewpoint using the plurality of captured images;

synthesize an image of the scene from the reference viewpoint using the plurality of captured images, where synthesizing the image involves using the depth map that specifies depths from the reference viewpoint for pixels in the synthesized image;

encode the synthesized image; and

store the synthesized image in an image file, and store the depth map and at least one of the plurality of captured images in the image file.

2. The system of claim 1, wherein the encoding application configures the processor to encode the depth map and store the depth map as metadata within the image file.

3. The system of claim 2, wherein the metadata also includes a description of a focal plane.

4. The system of claim 1, wherein:

synthesizing the image involves identifying pixels in the plurality of images of the scene that are occluded in the reference viewpoint; and

wherein the encoding application configure the processor to store metadata describing the encoded image in the image file, wherein the stored metadata includes descriptions of the occluded pixels.

5. The system of claim 4, wherein the descriptions of the occluded pixels include colors, locations, and depths of the occluded pixels.

6. The system of claim 1, wherein:

generating a depth map involves creating a confidence map for the depth map, where the confidence map indicates the reliability of the depth value for a pixel in the depth map; and

wherein the encoding application configure the processor to store metadata describing the encoded image in the image file, wherein the metadata includes the depth map and the confidence map.

7. The system of claim 6, wherein the encoding application configures the processor to encode the confidence map.

8. The system of claim 1, wherein:

the encoding application configures the processor to generate an edge map that indicates pixels in the synthesized image that lie on a discontinuity; and

wherein the encoding application configure the processor to store metadata describing the encoded image in the image file, wherein the metadata includes the edge map.

9. The system of claim 8, wherein the edge map identifies whether a pixel lies on an intensity discontinuity.

10. The system of claim 8, wherein the edge map identifies whether a pixel lies on an intensity and depth discontinuity.

11. The system of claim 8, wherein the encoding application configures the processor to encode the edge map.

12. The system of claim 1, wherein:

the encoding application configures the processor to generate a missing pixel map that indicates pixels in the synthesized image that do not correspond to a pixel from the plurality of images of the scene and that are generated by interpolating pixel values from adjacent pixels in the synthesized image; and

wherein the encoding application configure the processor to store metadata describing the encoded image in the image file, wherein the metadata includes the missing pixels map.

13. The system of claim 12, wherein the encoding application configures the processor to encode the missing pixels map.

14. The system of claim 1, wherein the image file conforms to the JPEG File Interchange Format (JFIF) standard.

15. The system of claim 14, wherein the synthesized image is encoded in accordance with the Joint Photographic Experts Group (JPEG) standard.

16. The system of claim 15, wherein the encoding application configure the processor to store metadata describing the encoded image within an application marker segment within the image file.

17. The system of claim 16, wherein the application marker segment is identified using an APP9 marker.

18. The system of claim 16, wherein the encoding application configures the processor to encode the depth map using lossless compression and the encoded depth map is stored within the application marker segment containing the metadata describing the encoded image.

19. The system of claim 1, wherein the depth map and at least one of the plurality of captured images are stored as metadata in the image file.

20. A method for encoding light field image data as a image file, comprising:

capture a plurality of images of a scene from different viewpoints by an array of cameras;

generate a depth map that specifies depths for pixels from a reference viewpoint using the plurality of captured images using a processor;

synthesize an image of a scene from the reference viewpoint based upon the plurality of captured images using a processor, wherein synthesizing the image involves using the depth map that specifies depths from the reference viewpoint for pixels in the synthesized image;

encoding the synthesized image using a processor; and

storing the synthesized image in an image file using a processor, and storing the depth map and at least one of the plurality of captured images in the image file.

21. A non-transitory machine readable medium containing processor instructions, where execution of the instructions by a processor causes the processor to perform a process comprising:

controlling capturing of a plurality of images of a scene from different viewpoints by an array of cameras;

generating a depth map that specifies depths for pixels from a reference viewpoint using the plurality of captured images;

synthesizing an image of a scene from the reference viewpoint using the plurality of captured images, wherein synthesizing the image involves using the depth map that specifies depths from the reference viewpoint for pixels in the synthesized image;

encoding the synthesized image; and

storing the synthesized image in an image file, and storing the depth map and at least one of the plurality of captured images in the image file.