Granted Patent B2

US 12,519,933 · App. 18/779,749 · Granted Jan 6, 2026

Inventor: Ki Baek Kim (Seoul, KR)

Assignee: B1 INSTITUTE OF IMAGE TECHNOLOGY, INC.

H04N19/105H04N19/176H04N19/186H04N19/30

Abstract

Claims (55)

1 . A method of decoding an image, comprising:

determining whether a color copy mode is supported for a current chroma block of a first color space in the image, wherein the color copy mode is a mode of predicting the current chroma block of the first color space by using a luma block of a second color space reconstructed before the current chroma block;

down-sampling the luma block corresponding to the current chroma block in response to the determination that the color copy mode is supported for the current chroma block;

deriving correlation information for the color copy mode based on a pre-determined reference region, wherein the correlation information represents a correlation between the current chroma block and the luma block, and the correlation information is expressed by a weight parameter and an offset parameter to be applied to the down-sampled luma block;

predicting the current chroma block by applying the correlation information to the down-sampled luma block for generating a prediction block of the current chroma block; and

reconstructing the current chroma block based on the prediction block,

wherein the reference region includes at least one of a neighboring region of the current chroma block or a neighboring region of the luma block,

wherein a number of reference pixel lines belonging to the reference region used for deriving the correlation information is adaptively determined based on a determination of whether the current chroma block is located on a boundary of a maximum coding block,

wherein the down-sampling of the luma block is performed using a first pixel of the luma block corresponding to a current pixel of the current chroma block and a plurality of neighboring pixels adjacent to the first pixel, positions of the plurality of neighboring pixels being determined based on a chroma format of the image, and

wherein the neighboring pixels include at least one of a right neighboring pixel, a bottom neighboring pixel or a bottom-right neighboring pixel.

2 . The method of claim 1 , the method further comprising:

obtaining, from a bitstream, first information indicating whether the color copy mode is supported,

wherein whether the color copy mode is supported for the current chroma block is determined based on the first information.

3 . The method of claim 1 , wherein the correlation information is derived using only some of pixels in the reference region.

4 . The method of claim 1 , wherein a number of the correlation information to be applied to the down-sampled luma block is greater than or equal to 3.

5 . A method of encoding an image, comprising:

determining whether a color copy mode is supported for a current chroma block of a first color space in the image, wherein the color copy mode is a mode of predicting the current chroma block of the first color space by using a luma block of a second color space reconstructed before the current chroma block;

down-sampling the luma block corresponding to the current chroma block in response to the determination that the color copy mode is supported for the current chroma block;

determining correlation information for the color copy mode based on a pre-determined reference region, wherein the correlation information represents a correlation between the current chroma block and the luma block, and the correlation information is expressed by a weight parameter and an offset parameter to be applied to the down-sampled luma block;

predicting the current chroma block by applying the correlation information to the down-sampled luma block for generating a prediction block of the current chroma block; and

encoding the current chroma block based on the prediction block,

wherein the reference region includes at least one of a neighboring region of the current chroma block or a neighboring region of the luma block,

wherein a number of reference pixel lines belonging to the reference region used for deriving the correlation information is adaptively determined based on a determination of whether the current chroma block is located on a boundary of a maximum coding block,

wherein the down-sampling of the luma block is performed using a first pixel of the luma block corresponding to a current pixel of the current chroma block and a plurality of neighboring pixels adjacent to the first pixel, positions of the plurality of neighboring pixels being determined based on a chroma format of the image, and

wherein the neighboring pixels include at least one of a right neighboring pixel, a bottom neighboring pixel or a bottom-right neighboring pixel.

6 . A non-transitory computer readable medium having stored thereon instructions that when executed by a processor perform a method, comprising:

determining whether a color copy mode is supported for a current chroma block of a first color space in an image, wherein the color copy mode is a mode of predicting the current chroma block of the first color space by using a luma block of a second color space reconstructed before the current chroma block;

down-sampling the luma block corresponding to the current chroma block in response to the determination that the color copy mode is supported for the current chroma block;

deriving correlation information for the color copy mode based on a pre-determined reference region, wherein the correlation information represents a correlation between the current chroma block and the luma block, and the correlation information is expressed by a weight parameter and an offset parameter to be applied to the down-sampled luma block;

predicting the current chroma block by applying the correlation information to the down-sampled luma block for generating a prediction block of the current chroma block; and

encoding the current chroma block based on the prediction block,

wherein the reference region includes at least one of a neighboring region of the current chroma block or a neighboring region of the luma block,

wherein a number of reference pixel lines belonging to the reference region used for deriving the correlation information is adaptively determined based on a determination of whether the current chroma block is located on a boundary of a maximum coding block,

wherein the down-sampling of the luma block is performed using a first pixel of the luma block corresponding to a current pixel of the current chroma block and a plurality of neighboring pixels adjacent to the first pixel, positions of the plurality of neighboring pixels being determined based on a chroma format of the image, and

wherein the neighboring pixels include at least one of a right neighboring pixel, a bottom neighboring pixel or a bottom-right neighboring pixel.

7 . A non-transitory computer readable medium storing a bitstream generated by a method of encoding an image, the method comprising:

determining whether a color copy mode is supported for a current chroma block of a first color space in the image, wherein the color copy mode is a mode of predicting the current chroma block of the first color space by using a luma block of a second color space reconstructed before the current chroma block;

down-sampling the luma block corresponding to the current chroma block in response to the determination that the color copy mode is supported for the current chroma block;

determining correlation information for the color copy mode based on a pre-determined reference region, wherein the correlation information represents a correlation between the current chroma block and the luma block, and the correlation information is expressed by a weight parameter and an offset parameter to be applied to the down-sampled luma block;

predicting the current chroma block by applying the correlation information to the down-sampled luma block for generating a prediction block of the current chroma block; and

encoding the current chroma block based on the prediction block,

wherein the reference region includes at least one of a neighboring region of the current chroma block or a neighboring region of the luma block,

wherein a number of reference pixel lines belonging to the reference region used for deriving the correlation information is adaptively determined based on a determination of whether the current chroma block is located on a boundary of a maximum coding block,

wherein the down-sampling of the luma block is performed using a first pixel of the luma block corresponding to a current pixel of the current chroma block and a plurality of neighboring pixels adjacent to the first pixel, positions of the plurality of neighboring pixels being determined based on a chroma format of the image, and

wherein the neighboring pixels include at least one of a right neighboring pixel, a bottom neighboring pixel or a bottom-right neighboring pixel.

8 . A method of transmitting a bitstream generated by an image encoding method, the image encoding method comprising:

determining whether a color copy mode is supported for a current chroma block of a first color space in the image, wherein the color copy mode is a mode of predicting the current chroma block of the first color space by using a luma block of a second color space reconstructed before the current chroma block;

down-sampling the luma block corresponding to the current chroma block in response to the determination that the color copy mode is supported for the current chroma block;

determining correlation information for the color copy mode based on a pre-determined reference region, wherein the correlation information represents a correlation between the current chroma block and the luma block, and the correlation information is expressed by a weight parameter and an offset parameter to be applied to the down-sampled luma block;

predicting the current chroma block by applying the correlation information to the down-sampled luma block for generating a prediction block of the current chroma block; and

encoding the current chroma block based on the prediction block,

wherein the reference region includes at least one of a neighboring region of the current chroma block or a neighboring region of the luma block,

wherein a number of reference pixel lines belonging to the reference region used for deriving the correlation information is adaptively determined based on a determination of whether the current chroma block is located on a boundary of a maximum coding block,

wherein the down-sampling of the luma block is performed using a first pixel of the luma block corresponding to a current pixel of the current chroma block and a plurality of neighboring pixels adjacent to the first pixel, positions of the plurality of neighboring pixels being determined based on a chroma format of the image, and

wherein the neighboring pixels include at least one of a right neighboring pixel, a bottom neighboring pixel or a bottom-right neighboring pixel.

Priority Claims (3)

Continuity (5)

References Cited (71)