Method and System for Processing Multiview Videos for View Synthesis Using Skip and Direct Modes

• US 20120062756A1
• Filed: 11/17/2011
• Published: 03/15/2012
• Est. Priority Date: 12/17/2004
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Vetro, Anthony, Tian, Dong, Cheung, Ngai-Man
• Granted Patent: US 8,854,486 B2
• Time in Patent Office: Days
• US Class Current: 348/218.1
• CPC Class Codes: H04N 19/105 Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
• CPC Class Codes: H04N 19/122 Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/174 the region being a slice, e.g. a line of blocks or a group of blocks
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/27 involving both synthetic and natural picture components, e.g. synthetic natural hybrid coding [SNHC]
• CPC Class Codes: H04N 19/423 characterised by memory arrangements H04N19/433 takes precedence
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/52 by predictive encoding
• CPC Class Codes: H04N 19/54 using feature points or meshes
• CPC Class Codes: H04N 19/573 Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/597 specially adapted for multi-view video sequence encoding
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/615 using motion compensated temporal filtering [MCTF]
• CPC Class Codes: H04N 19/619 : the transform being operated outside the prediction loop
• CPC Class Codes: H04N 19/63 : using sub-band based transform, e.g. wavelets
• CPC Class Codes: H04N 19/635 : characterised by filter definition or implementation details
• CPC Class Codes: H04N 19/70 : characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 7/181 : for receiving images from a plurality of remote sources

Abstract

Multiview videos are acquired by overlapping cameras. Side information is used to synthesize multiview videos. A reference picture list is maintained for current frames of the multiview videos, the reference picture indexes temporal reference pictures and spatial reference pictures of the acquired multiview videos and the synthesized reference pictures of the synthesized multiview video. Each current frame of the multiview videos is predicted according to reference pictures indexed by the associated reference picture list with a skip mode and a direct mode, whereby the side information is inferred from the synthesized reference picture. Alternatively, the depth images corresponding to the multiview videos of the input data, and this data are encoded as part of the bitstream depending on a SKIP type.

Claims

1. A method for processing a plurality of multiview videos of a scene, in which each video is acquired by a corresponding camera arranged at a particular pose, and in which a view of each camera overlaps with the view of at least one other camera, comprising the steps of:

obtaining side information for synthesizing a particular view of multiview video;

synthesizing a synthesized multiview video from the plurality of multiview videos and the side information;

maintaining a reference picture list for each current frame of each of the plurality of multiview videos, the reference picture indexing temporal reference it pictures and spatial reference pictures of the plurality of acquired multiview videos and the synthesized reference pictures of the synthesized multiview video; and

predicting each current frame of the plurality of multiview videos according to reference pictures indexed by the associated reference picture list with an adaptive-reference skip mode or an adaptive-reference direct mode, wherein the adaptive-reference skip mode and adaptive-reference direct mode use one of the plurality of reference pictures.

2. The method of claim 1 in which the adaptive-reference skip mode is with respect to the synthesized reference picture.

3. The method of claim 1 in which the adaptive-reference skip mode is with respect to a temporal reference picture.

4. The method of claim 1 in which the adaptive-reference skip mode is with respect to a spatial reference picture.

5. The method of claim 1 in which the adaptive-reference skip mode is signaled by adding an additional bit.

6. The method of claim 5 in which the additional bit is added when a mb_skip_flag is equal to 1 to distinguish a conventional, skip mode from the adaptive-reference skip mode.

7. The method of claim 1 in which the adaptive-reference skip mode is signaled at a slice layer to collectively signal the adaptive-reference skip mode for all macroblocks in the slice.

8. The method of claim 1, further comprising:

deriving the reference picture index for a block of each current frame using the reference picture indices of neighboring blocks.

9. The method of claim 8 in which the adaptive-reference skip mode is signaled for P-slices, where a first synthesized reference picture in the reference picture list is chosen as the reference picture if the derived reference picture index is associated with a non-synthesized reference picture.

10. The method of claim 8 in which the adaptive-reference skip mode is signaled for B-slices, where an earliest synthesized reference picture in the reference picture list is chosen as the reference picture if the derived reference picture index is associated with a non-synthesized reference picture.

11. The method of claim 8 in which the adaptive-reference skip mode is signaled for P-slices, where a first non-synthesized reference picture in the reference picture list is chosen as the reference picture if the derived reference picture index is associated with a synthesized reference picture.

12. The method of claim 8 in which the adaptive-reference skip mode is signaled for B-slices, where an earliest non-synthesized reference picture in the reference picture list is chosen as the reference picture if the derived reference picture index is associated with a synthesized reference picture.

13. The method of claim 1 in which the adaptive-reference direct mode is with respect to the synthesized reference picture.

14. The method of claim 1 in which the adaptive-reference direct mode is with respect to a temporal reference picture.

15. The method of claim 1 in which the adaptive-reference direct mode is with respect to a spatial reference picture.

16. The method of claim 1 in which the adaptive-reference direct mode is signaled by adding an additional hit.

17. The method of claim 16 in which the additional hit distinguishes a conventional direct mode from the adaptive-reference direct mode.

18. The method of claim 1 in which the adaptive-reference direct mode is signaled at a slice layer to collectively signal the adaptive-reference direct mode for all macroblocks in the slice.

19. The method of claim 8 in which the adaptive-reference direct mode is signaled for B-slices, where an earliest synthesized reference picture in the reference picture list is chosen as the reference picture if the derived reference picture index is associated with a non-synthesized reference picture.

20. The method of claim 8 in which the adaptive-reference direct mode is signaled for B-slices, where an earliest non-synthesized reference picture in the reference picture list is chosen as the reference picture if the derived reference picture index is associated with a synthesized reference picture.

21. The method of claim 1, in which the side information includes depth values.

22. The method of claim 1, in which the side information is obtained in an encoder.

23. The method of claim 1, in which the side information is obtained in a decoder.

24. A system for processing a plurality of multiview videos of a scene, comprising:

a plurality of cameras, each camera configured to acquire a multiview video of a scene, each camera arranged at a particular pose, and in which a view of each camera overlaps with the view of at least one other camera;

means for obtaining side information for synthesizing a particular view of the multiview video;

means for synthesizing a synthesized multiview video from the plurality of multiview videos and the side information;

a memory buffer configured to maintain a reference picture list for each current frame of each of the plurality of multiview videos, the reference picture indexing temporal reference pictures and spatial reference pictures of the plurality of acquired multiview videos and the synthesized reference pictures of the synthesized multiview video; and

means for predicting each current frame of the plurality of multiview videos according to reference pictures indexed by the associated reference picture list with an adaptive-reference skip mode or an adaptive-reference direct mode, wherein the adaptive-reference skip mode and adaptive-reference direct mode use one of the plurality of reference pictures.