# US 12,225,230 B2 · Image prediction method and apparatus for performing intra prediction

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- Number: US 12,225,230 B2
- Document ID: US12225230B2
- Status: Granted
- Kind: B2
- Application number: 18/385,897
- Filed: 2023-10-31
- Published: 2024-02-29
- Granted: 2025-02-11
- Earliest claimed: 2018-09-14
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Sunmi Yoo; Jin Heo
- Web page: https://patentgrep.com/patent/US12225230B2

## CPC

- H04N 19/593: involving spatial prediction techniques
- H04N 19/11: among a plurality of spatial predictive coding modes
- H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635)
- H04N 19/132: Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
- H04N 19/136: Incoming video signal characteristics or properties
- 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
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/182: the unit being a pixel
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image decoding method according to the present document may comprise the steps of: deriving an intra prediction mode for a current block; deriving reference samples located around the current block; generating a prediction sample for the current block on the basis of the intra prediction mode and the reference samples; and generating residual samples for the current block on the basis of the prediction sample, wherein the step of generating the prediction sample for the current block may comprise the steps of: deriving an interpolation filter, which is to be applied to the reference sample, on the basis of the prediction mode of the current block or the size of the current block; and generating the prediction sample by applying the derived interpolation filter to the reference sample.

## Claims

### Claim 1

A decoding apparatus for an image decoding, the decoding apparatus comprising:
a memory; and
at least one processor connected to the memory, the at least one processor configured to:
derive an intra prediction mode for a current block;
derive reference samples contiguous to the current block;
generate a prediction sample for the current block based on the intra prediction mode and the reference samples; and
generate a reconstructed picture for the current block based on the prediction sample,
wherein the generating of the prediction sample for the current block includes:
deriving an interpolation filter to be applied to the reference samples based on a prediction mode of the current block or a size of the current block; and
generating the prediction sample by applying the derived interpolation filter to the reference samples,
wherein the deriving of the interpolation filter includes:
comparing a distance between the prediction sample and the reference samples with a predetermined threshold value; and
deriving the interpolation filter as a Gaussian filter based on the distance exceeding the predetermined threshold value or as a cubic filter based on the distance being less than or equal to the predetermined threshold value,
wherein the distance is derived based on the prediction mode of the current block, and the predetermined threshold value is derived based on the size of the current block.

### Claim 2 (depends on 1)

The decoding apparatus of claim 1, wherein the deriving of the interpolation filter includes:
comparing a prediction angle between a direction of the prediction mode of the current block and a vertical direction or a horizontal direction with a preset threshold value; and
deriving the interpolation filter as either a first interpolation filter or a second interpolation filter depending on a comparison result of the prediction angle and the preset threshold value.

### Claim 3 (depends on 2)

The decoding apparatus of claim 2, wherein the preset threshold value is set differently depending on the size of the current block.

### Claim 4 (depends on 2)

The decoding apparatus of claim 2, wherein:
the interpolation filter is derived as the first interpolation filter based on the prediction angle being exceed the preset threshold value;
the interpolation filter is derived as the second interpolation filter based on the prediction angle being less than or equal to the preset threshold value; and
the first interpolation filter is a Gaussian filter, and the second interpolation filter is a cubic filter.

### Claim 5

An encoding apparatus for an image encoding, the encoding apparatus comprising:
a memory; and
at least one processor connected to the memory, the at least one processor configured to:
derive an intra prediction mode for a current block;
derive reference samples contiguous to the current block;
generate a prediction sample for the current block based on the intra prediction mode and the reference samples;
generate residual samples for the current block based on the prediction sample; and
encode image information including information on the intra prediction mode and the residual sample,
wherein the generating of the prediction sample for the current block includes:
deriving an interpolation filter to be applied to the reference samples based on a prediction mode of the current block or a size of the current block; and
generating the prediction sample by applying the derived interpolation filter to the reference samples,
wherein the deriving of the interpolation filter includes:
comparing a distance between the prediction sample and the reference samples with a predetermined threshold value; and
deriving the interpolation filter as a Gaussian filter based on the distance exceeding the predetermined threshold value or as a cubic filter based on the distance being less than or equal to the predetermined threshold value,
wherein the distance is derived based on the prediction mode of the current block, and the predetermined threshold value is derived based on the size of the current block.

### Claim 6 (depends on 5)

The encoding apparatus of claim 5, wherein the deriving of the interpolation filter includes:
comparing a prediction angle between a direction of the prediction mode of the current block and a vertical direction or a horizontal direction with a preset threshold value; and
deriving the interpolation filter as either a first interpolation filter or a second interpolation filter depending on a comparison result of the prediction angle and the preset threshold value.

### Claim 7 (depends on 6)

The encoding apparatus of claim 6, wherein the preset threshold value is set differently depending on the size of the current block.

### Claim 8 (depends on 6)

The encoding apparatus of claim 6, wherein:
the interpolation filter is derived as the first interpolation filter based on the prediction angle being exceed the preset threshold value;
the interpolation filter is derived as the second interpolation filter based on the prediction angle being less than or equal to the preset threshold value; and
the first interpolation filter is a Gaussian filter, and the second interpolation filter is a cubic filter.

### Claim 9

An apparatus for transmitting data for an image, the apparatus comprising:
at least one processor configured to obtain a bitstream for the image, wherein the bitstream is generated based on deriving an intra prediction mode for a current block, deriving reference samples contiguous to the current block, generating a prediction sample for the current block based on the intra prediction mode and the reference samples, generating residual samples for the current block based on the prediction sample, and encoding image information including information on the intra prediction mode and the residual sample,
a transmitter configured to transmit the data comprising the bitstream,
wherein the generating of the prediction sample for the current block includes:
deriving an interpolation filter to be applied to the reference samples based on a prediction mode of the current block or a size of the current block; and
generating the prediction sample by applying the derived interpolation filter to the reference samples,
wherein the deriving of the interpolation filter includes:
comparing a distance between the prediction sample and the reference samples with a predetermined threshold value; and
deriving the interpolation filter as a Gaussian filter based on the distance exceeding the predetermined threshold value or as a cubic filter based on the distance being less than or equal to the predetermined threshold value,
wherein the distance is derived based on the prediction mode of the current block, and the predetermined threshold value is derived based on the size of the current block.