Image encoding method and apparatus, and image decoding method and apparatus

Patent metadata

Field	Value
Publication number	US-2020252614-A1
Application number	US-201816651809-A
Country	US
Kind code	A1
Filing date	Sep 27, 2018
Priority date	Sep 28, 2017
Publication date	Aug 6, 2020
Grant date	—

Abstract

Provided is an image decoding method including: generating an intra prediction value of a current sample based on a position of the current sample in a current block and an intra prediction mode of the current block; determining, based on the position of the current sample in the current block, a sample value of at least one filtering reference sample to be filtered and a first weight with respect to the filtering reference sample and a second weight with respect to the intra prediction value of the current sample; generating a filtered prediction sample value of the current sample based on the determined sample value of the filtering reference sample to be filtered, the intra prediction value of the current sample, the first weight with respect to the filtering reference sample, and the second weight with respect to the intra prediction value of the current sample; and generating a prediction block of the current block, the prediction block including the filtered prediction sample value of the current sample.

First claim

1 . An image decoding method comprising:
obtaining, from a bitstream, information about a transform coefficient of a current block; generating an intra prediction value of a current sample based on a position of the current sample in the current block and an intra prediction mode of the current block; determining, based on the position of the current sample in the current block, a sample value of at least one filtering reference sample to be filtered and a first weight with respect to the filtering reference sample and a second weight with respect to the intra prediction value of the current sample, and generating a filtered prediction sample value of the current sample based on the determined sample value of the filtering reference sample to be filtered, the intra prediction value of the current sample, the first weight with respect to the filtering reference sample, and the second weight with respect to the intra prediction value of the current sample; generating a prediction block of the current block, the prediction block including the filtered prediction sample value of the current sample; obtaining a residual block of the current block based on the obtained information about the transform coefficient of the current block; and reconstructing the current block based on the prediction block of the current block and the residual block of the current block.

2 . The image decoding method of claim 1 , wherein the generating of the intra prediction value of the current sample based on the position of the current sample in the current block and the intra prediction mode of the current block comprises:
determining an original reference sample corresponding to the current sample based on the position of the current sample and the intra prediction mode of the current block; and generating the intra prediction value of the current sample based on a sample value of the original reference sample.

3 . The image decoding method of claim 1 , wherein the first weight with respect to the filtering reference sample is determined based on a distance between the filtering reference sample and the current sample.

4 . The image decoding method of claim 3 , wherein the first weight with respect to the filtering reference sample is determined based on a distance between the filtering reference sample and the current sample, compared to a size of the current block.

5 . The image decoding method of claim 3 , wherein the greater the distance between the filtering reference sample and the current sample, the smaller the first weight with respect to the filtering reference sample.

6 . The image decoding method of claim 1 , wherein the filtering reference sample includes at least one of an original reference sample located in a horizontal direction of the current sample and an original reference sample located in a vertical direction of the current sample.

7 . The image decoding method of claim 1 , wherein when the intra prediction mode of the current block is an angular mode,
the filtering reference sample includes at least one of adjacent samples on the left and on the top of the current sample located on a line passing by the current sample, and the line is in a prediction direction indicated by the angular mode and an opposite direction to the prediction direction.

8 . The image decoding method of claim 1 , wherein the determining, based on the position of the current sample in the current block, of a sample value of at least one filtering reference sample to be filtered and a first weight with respect to the filtering reference sample and a second weight with respect to an intra prediction value of the current sample, and generating a filtered prediction sample value of the current sample based on the determined sample value of the filtering reference sample to be filtered, the intra prediction value of the current sample, the first weight with respect to the filtering reference sample, and the second weight with respect to the intra prediction value of the current sample comprise:
determining at least one second intra prediction mode; and by using the determined at least one second intra prediction mode, determining, based on the position of the current sample in the current block, a sample value of at least one filtering reference sample to be filtered and a first weight with respect to the filtering reference sample and a second weight with respect to the intra prediction value of the current sample, and generating a filtered prediction sample value of the current sample based on the determined sample value of the filtering reference sample to be filtered, the intra prediction value of the current sample, the first weight with respect to the filtering reference sample, and the second weight with respect to the intra prediction value of the current sample.

9 . The image decoding method of claim 8 , wherein the at least one second intra prediction mode is determined in units of pictures or in units of blocks.

10 . The image decoding method of claim 1 , wherein the at least one second intra prediction mode is determined to be at least one of the intra prediction mode, an intra prediction mode indicating an opposite direction to a prediction direction indicated by the intra prediction mode, a horizontal mode, and a vertical mode.

11 . The image decoding method of claim 1 , wherein the first weight and the second weight are normalized values.

12 . The image decoding method of claim 1 , wherein the determining, based on the position of the current sample in the current block, a sample value of at least one filtering reference sample to be filtered and a first weight with respect to the filtering reference sample and a second weight with respect to the intra prediction value of the current sample, and generating a filtered prediction sample value of the current sample based on the determined sample value of the filtering reference sample to be filtered, the intra prediction value of the current sample, the first weight with respect to the filtering reference sample, and the second weight with respect to the intra prediction value of the current sample comprise:
when the intra prediction mode is a predetermined intra prediction mode, determining, based on the position of the current sample in the current block, a sample value of at least one filtering reference sample to be filtered and a first weight with respect to the filtering reference sample and a second weight with respect to the intra prediction value of the current sample, and generating a filtered prediction sample value of the current sample based on the determined sample value of the filtering reference sample to be filtered, the intra prediction value of the current sample, the first weight with respect to the filtering reference sample, and the second weight with respect to the intra prediction value of the current sample.

13 . An image encoding method comprising:
generating an intra prediction value of a current sample based on a position of the current sample in a current block and an intra prediction mode of the current block; determining, based on the position of the current sample in the current block, a sample value of at least one filtering reference sample to be filtered and a first weight with respect to the filtering reference sample and a second weight with respect to the intra prediction value of the current sample, and generating a filtered prediction sample value of the current sample based on the determined sample value of the filtering reference sample to be filtered, the intra prediction value of the current sample, the first weight with respect to the filtering reference sample, and the secon

Assignees

• Samsung Electronics Co Ltd

Inventors

• Choi Na-Rae
• Jin Bo-Ra
• Park Min-Woo

Classifications

• H04N19/159

  Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction · CPC title

• H04N19/132 Primary

  Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking · CPC title

• H04N19/635

  characterised by filter definition or implementation details · CPC title

• H04N19/189

  characterised by the adaptation method, adaptation tool or adaptation type used for the adaptive coding · CPC title

• H04N19/593 Primary

  involving spatial prediction techniques · CPC title