SYSTEMS AND METHODS FOR MASK BASED PROCESSING OF A BLOCK OF A DIGITAL IMAGE

• US 20170251227A1
• Filed: 05/12/2017
• Published: 08/31/2017
• Est. Priority Date: 11/14/2014
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Dvir, Itsik, Peterfreund, Natan, Irony, Dror, Drezner, David
• Granted Patent: US 10,602,186 B2
• Time in Patent Office: Days
• CPC Class Codes: H04N 19/119 Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
• 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 19/146 Data rate or code amount at the encoder output
• CPC Class Codes: H04N 19/156 Availability of hardware or computational resources, e.g. encoding based on power-saving criteria
• CPC Class Codes: H04N 19/157 Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/182 the unit being a pixel
• CPC Class Codes: H04N 19/196 being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters processing of motion vectors H04N19/513
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/625 using discrete cosine transform [DCT]
• CPC Class Codes: H04N 19/649 the transform being applied to non rectangular image segments

Abstract

There is provided an apparatus for generating a set of transform coefficients of a block in a frame or portion thereof. The apparatus includes a media encoder coupled to a data interface configured to receive a frame or portion thereof. The media encoder is configured to: designate a rotational symmetry mask having a size and a shape as the block partitioned in the frame or portion thereof for processing the block; split the block to two complementary portions using the rotational symmetry mask; generate a pair of rotational symmetry blocks each having one of the two complementary portions; and compute a transform coefficient for each member of the pair of rotational symmetry blocks.

Claims

1. An apparatus for generating a set of transform coefficients of a block in a frame or portion thereof, the apparatus comprising:

a media encoder coupled to a data interface adapted to receive a frame or portion thereof, wherein the media encoder is configured to;

designate a rotational symmetry mask having a size and a shape as the block partitioned in the frame or portion thereof for processing the block;

split the block to two complementary portions using the rotational symmetry mask;

generate a pair of rotational symmetry blocks each having one of the two complementary portions; and

compute a transform coefficient for each member of the pair of rotational symmetry blocks.

2. The apparatus of claim 1, wherein the media encoder is configured to generate each pair of rotational symmetry blocks in a size and a shape of the block by adding complementary data to the respective portion of one of the two complementary portions.

3. The apparatus of claim 2, wherein the complementary data is a 2D mirror of the respective portion which the rotational symmetry block is constructed from by multiplication by one member of the group consisting of:

zero (0), one (1) and minus one (−

1).

4. The apparatus of claim 1, wherein the media encoder is configured to designate the rotational symmetry mask by identifying a pattern of pixel values in the block.

5. The apparatus of claim 1, wherein the rotational symmetry mask is a binary mask defining a split of the block into the two complementary portions such that the shape of the block and the split are invariant under 180 degree rotation of the block with respect to a center of the block.

6. The apparatus of claim 1, wherein the block is an M×

N block, wherein the rotational symmetry mask is adapted to define a split of the M×

N block into two complementary groups such that when a certain pixel located at (m,n) is assigned to a first group a corresponding pixel located at (M−

m−

1, N−

n−

1) is assigned to a second group.

7. The apparatus of claim 1, wherein the rotational symmetry mask is configured to define two complementary portions wherein at least one portion includes a likelihood of certain pixel characteristics above a predefined threshold value.

8. The apparatus of claim 1, wherein the rotational symmetry mask is configured to define a line which joins opposing edges of a two dimensional space to split the two dimensional space to two 2D-mirrored complementary portions.

9. The apparatus of claim 1, wherein:

the data interface is further configured to receive at least one transform coefficient representing at least one member of a pair of rotational symmetry blocks, the transform coefficients coding a block in a frame or portion thereof, and a signal representing an associated designated rotation symmetry mask having a size and a shape as the block partitioned in the frame or portion thereof for processing the block; and

the media encoder is further configured to;

compute the pair of rotational symmetry blocks based on inverse transform of the received at least one transform coefficient, each member of the pair of rotational symmetry blocks having one of two complementary portions, and

reconstruct a block partitioned in same frame or portion thereof from the two complementary portions based on the rotational symmetry mask.

10. A method for generating a set of coefficients of a block in a frame or portion thereof, the method comprising:

designating a rotational symmetry mask having a size and a shape as a block partitioned in the frame or portion thereof for processing the block;

splitting the block to two complementary portions using the rotational symmetry mask;

generating a pair of rotational symmetry blocks each having one of the two complementary portions; and

computing a transform coefficient for each member of the pair of rotational symmetry blocks.

11. The method of claim 10, wherein the rotation symmetry mask is designated from a plurality of rotation symmetry masks which define a plurality of different rotational symmetries.

12. The method of claim 10, wherein designating the rotational symmetry mask is performed according to a pattern of pixel values in the block.

13. The method of claim 10, wherein designating the rotational symmetry mask is based on content extracted from at least one of spatial neighboring blocks of the block and temporal neighboring blocks of the block.

14. The method of claim 13 wherein the content is extracted according to a pattern of pixel values in at least one of the spatial and temporal neighboring blocks.

15. The method of claim 10, wherein designating the rotational symmetry mask is performed based on information associated with at least one of spatial and temporal neighboring blocks of the block.

16. The method of claim 15 wherein the information associated with at least one of spatial and temporal neighboring blocks is related to prediction.

17. The method of claim 16 wherein the prediction is related to the direction mode of an intra predictor.

18. The method of claim 10, wherein computing the transform coefficient is based on a 2D Discrete Orthogonal Transform which maintains the rotational symmetry condition calculated by the equation:

T_p,q(M−

m−

1, N−

n−

1)=(−

1)^(p+q)T_p,q(m,n),

Wherein;

{T_p,q(m,n)} denotes the 2D transformation basis;

(m,n) denotes a pixel location; and

m=0,1, . . . , M−

1;

n=0,1, . . . , N−

1;

p and q denote the spatial frequencies;

p=0,1, . . . , M−

1;

q=0,1, . . . , N−

1.

19. A method for reconstructing a block of a frame or portion thereof based on a set of transform coefficients, the method comprising:

receiving a set of transform coefficients representing each member of a pair of rotational symmetry blocks, the transform coefficients representing data of a block in the frequency domain;

receiving a signal representing an associated designated rotation symmetry mask, the rotational symmetry mask having a size and a shape as the block partitioned in the frame or portion thereof for processing the block;

computing the pair of rotational symmetry blocks based on inverse transform of the received set of transform coefficient, each member of the pair of rotational symmetry blocks having one of two complementary portions; and

reconstructing the block from the two complementary portions based on the rotational symmetry mask.

20. An apparatus for decoding a block in a frame or portion thereof, the apparatus comprising:

a media decoder coupled to a data interface and configured to;

receive at least one transform coefficient representing at least one member of a pair of rotational symmetry blocks, the transform coefficients coding a block in a frame or portion thereof, and

receive a signal representing an associated designated rotation symmetry mask having a size and a shape as the block partitioned in the frame or portion thereof for processing the block;

compute the pair of rotational symmetry blocks based on inverse transform of the received at least one transform coefficient, each member of the pair of rotational symmetry blocks having one of two complementary portions; and

reconstruct a block partitioned in same frame or portion thereof from the two complementary portions based on the rotational symmetry mask.

21. A method for reconstructing a block of a frame or portion thereof based on a set of transform coefficients, the method comprising:

receiving a set of transform coefficients representing each member of a pair of rotational symmetry blocks, the transform coefficients represent the data of a block in the frequency domain;

receiving a signal representing an associated designated rotation symmetry mask, the rotational symmetry mask having a size and a shape as the block partitioned in the frame or portion thereof for processing the block;

computing the pair of rotational symmetry blocks based on inverse transform of the received set of transform coefficient, each member of the pair of rotational symmetry blocks having one of two complementary portions; and

reconstructing the block from the two complementary portions based on the rotational symmetry mask.