# US 12,225,222 B2 · Image encoding/decoding method and device, and recording medium in which bitstream is stored

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- Number: US 12,225,222 B2
- Document ID: US12225222B2
- Status: Granted
- Kind: B2
- Application number: 17/952,332
- Filed: 2022-09-26
- Published: 2023-01-12
- Granted: 2025-02-11
- Earliest claimed: 2016-11-29
- Assignees: Research & Business Foundation Sungkyunkwan University
- Applicants: Research & Business Foundation Sungkyunkwan University
- Inventors: Seung Hyun Cho; Jung Won Kang; Hyun Suk Ko; Sung Chang Lim; Jin Ho Lee; Ha Hyun Lee; Dong San Jun; Hui Yong Kim; Byeung Woo Jeon; Nam Uk Kim; Seung Su Jeon; Jin Soo Choi
- Web page: https://patentgrep.com/patent/US12225222B2

## CPC

- H04N 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
- H04N 19/593: involving spatial prediction techniques
- H04N 19/11: among a plurality of spatial predictive coding modes
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/186: the unit being a colour or a chrominance component
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

The present invention relates to an image encoding/decoding method and device. The image decoding method according to the present invention comprises the steps of: decoding a prediction mode index; determining whether the prediction mode index indicates function-based intra prediction; inducing a parameter (s) for generating a function, when the prediction mode index indicates the function-based intra prediction; generating the function on the basis of the induced parameter (s); and performing intra prediction by using the generated function.

## Claims

### Claim 1

A method of decoding an image, the method comprising:
decoding a prediction mode index of a current block;
determining whether or not a function-based intra-prediction is performed for the current block based on the prediction mode index;
performing intra-prediction for the current block for generating a prediction block of the current block;
generating a residual block by decoding a bitstream; and
reconstructing the current block by adding the prediction block to the residual block,
wherein, when the function-based intra-prediction is performed for the current block, the performing intra-prediction comprises
deriving a parameter for generating a function; and
performing intra-prediction by using the function based on the derived parameter,
wherein the prediction mode index is flag information signaled through a bitstream, having a first value indicating that the function-based intra-prediction is performed or a second value indicating that the function-based intra-prediction is not performed, and
wherein the parameter for generating the function is derived based on at least one among a maximum sample value and a minimum sample value of previously reconstructed reference samples neighboring the current block, the maximum sample value being a value of a sample having a maximum value among values of the previously reconstructed reference samples, and the minimum sample value being a value of a sample having a minimum value among the values of the previously reconstructed reference samples.

### Claim 2 (depends on 1)

The method of claim 1,
wherein the determining whether or not a function-based intra-prediction is performed for the current block is performed based on a color component of the current block.

### Claim 3 (depends on 1)

The method of claim 1,
wherein, when an upper boundary of the current block is a boundary of a coding tree block, a reference sample of intra-prediction is configured by using a first reference sample line only among a plurality of reference sample lines adjacent to the current block.

### Claim 4

A method of encoding an image, the method comprising:
determining whether or not to perform a function-based intra-prediction for the current block;
performing intra-prediction for the current block for generating a prediction block of the current block;
generating a residual block by subtracting the prediction block from the current block; and
encoding the current block by encoding the residual block into a bitstream,
wherein, when the function-based intra-prediction is performed for the current block, the performing intra-prediction comprises
deriving a parameter for generating a function;
performing intra-prediction by using the function based on the derived parameter; and
encoding a prediction mode index indicating that the function-based intra-prediction is performed for the current block,
wherein the prediction mode index is flag information signaled through a bitstream, having a first value indicating that the function-based intra-prediction is performed or a second value indicating that the function-based intra-prediction is not performed, and
wherein the parameter for generating the function is derived based on at least one among a maximum sample value and a minimum sample value of previously reconstructed reference samples neighboring the current block, the maximum sample value being a value of a sample having a maximum value among values of the previously reconstructed reference samples, and the minimum sample value being a value of a sample having a minimum value among the values of the previously reconstructed reference samples.

### Claim 5 (depends on 4)

The method of claim 4,
wherein the determining whether or not to perform a function-based intra-prediction for the current block is performed based on a color component of the current block.

### Claim 6

A computer-readable recording medium storing a bitstream which is generated by a method of encoding an image, the method comprising:
determining whether or not to perform a function-based intra-prediction for the current block;
performing intra-prediction for the current block for generating a prediction block of the current block;
generating a residual block by subtracting the prediction block from the current block; and
encoding the current block by encoding the residual block into the bitstream,
wherein, when the function-based intra-prediction is performed for the current block, the performing intra-prediction comprises
deriving a parameter for generating a function;
performing intra-prediction by using the function based on the derived parameter; and
encoding a prediction mode index indicating that the function-based intra-prediction is performed for the current block,
wherein the prediction mode index is flag information signaled through a bitstream, having a first value indicating that the function-based intra-prediction is performed or a second value indicating that the function-based intra-prediction is not performed, and
wherein the parameter for generating the function is derived based on at least one among a maximum sample value and a minimum sample value of previously reconstructed reference samples neighboring the current block, the maximum sample value being a value of a sample having a maximum value among values of the previously reconstructed reference samples, and the minimum sample value being a value of a sample having a minimum value among the values of the previously reconstructed reference samples.