Image encoding/decoding method and apparatus, and recording medium storing bitstream

Patent metadata

Field	Value
Publication number	US-2019166375-A1
Application number	US-201716321145-A
Country	US
Kind code	A1
Filing date	Aug 1, 2017
Priority date	Aug 1, 2016
Publication date	May 30, 2019
Grant date	—

Abstract

An image encoding/decoding method and apparatus for performing intra prediction are provided. An image decoding method of the present invention comprises deriving an intra prediction mode for a current block, selecting at least one reconstructed sample line neighboring to the current block, constructing a reference sample using at least one reconstructed sample included in the at least one reconstructed sample line, and performing intra prediction for the current block based on the intra prediction mode and the reference sample.

First claim

1 . An image decoding method comprising:
deriving an intra prediction mode for a current block; selecting at least one reconstructed sample line neighboring to the current block; constructing a reference sample using at least one reconstructed sample included in the at least one reconstructed sample line; and performing intra prediction for the current block based on the intra prediction mode and the reference sample.

2 . The image decoding method of claim 1 , wherein the at least one reconstructed sample line includes at least one of neighbor reconstructed sample lines adjacent to an upper side and a left side of the current block.

3 . The image decoding method of claim 2 , wherein the number of the neighbor reconstructed sample lines adjacent to the upper side and the left side is determined based on at least one of a size, a shape, and an intra prediction mode of the current block.

4 . The image decoding method of claim 1 , wherein the reference sample is derived using a weighted sum of the at least one reconstructed sample.

5 . The image decoding method of claim 4 , wherein the weighted sum is performed based on at least one of the intra prediction mode and a distance between the current block and the reconstructed sample line.

6 . The image decoding method of claim 1 , wherein the construction of a reference sample comprises:
searching a reconstructed sample similar to the current block from among reconstructed samples included in at least one of a top row and a left column neighboring to the current block; and replacing at least one reconstructed sample included in the reconstructed sample line with the searched reconstructed sample.

7 . The image decoding method of claim 1 , further comprising dividing the current block into a plurality of sub-blocks,
wherein intra prediction is performed for each of the plurality of sub-blocks based on a reference sample constructed on the basis of the current block.

8 . The image decoding method of claim 7 , wherein when intra prediction is performed for one of the plurality of sub-blocks using the reference sample constructed on the basis of the current block, the intra prediction is performed after compensating a reference sample which is not neighboring to the one sub-block.

9 . The image decoding method of claim 1 , wherein the performing of intra prediction comprises:
predicting at least one sample among samples included in a right column, samples included in a bottom row, and a bottom right sample within the current block, using the at least one reconstructed sample; and predicting remaining samples within the current block, using the at least one predicted sample.

10 . An image decoding apparatus comprising an intra predictor, wherein the intra predictor is configured to derive an intra prediction mode for a current block, to select at least one reconstructed sample line neighboring to the current block, to construct a reference sample using at least one reconstructed sample included in the at least one reconstructed sample line, and to perform intra prediction for the current block based on the intra prediction mode and the reference sample.

11 . An image encoding method comprising:
determining an intra prediction mode for a current block; selecting at least one reconstructed sample line neighboring to the current block; constructing a reference sample using at least one reconstructed sample included in the at least one reconstructed sample line; and performing intra prediction for the current block based on the intra prediction mode and the reference sample.

12 . The image encoding method of claim 11 , wherein the at least one reconstructed sample line includes at least one among reconstructed sample lines adjacent to an upper side and a left side of the current block.

13 . The image encoding method of claim 12 , wherein the number of the neighbor reconstructed sample lines adjacent to the upper side and the left side is determined based on at least one of a size, a shape, and an intra prediction mode of the current block.

14 . The image encoding method of claim 11 , wherein the reference sample is derived using a weighted sum of the at least one reconstructed sample.

15 . The image encoding method of claim 14 , wherein the weighted sum is performed based on at least one of the intra prediction mode and a distance between the current block and the reconstructed sample line.

16 . The image encoding method of claim 11 , wherein the construction of a reference sample comprises:
searching a reconstructed sample similar to the current block from among reconstructed samples included in at least one of an upper row and a left column neighboring to the current block; and replacing at least one reconstructed sample included in the reconstructed sample line with the searched reconstructed sample.

17 . The image encoding method of claim 11 , further comprising dividing the current block into a plurality of sub-blocks,
wherein intra prediction is performed for each of the plurality of sub-blocks based on a reference sample constructed on the basis of the current block.

18 . The image encoding method of claim 17 , wherein when intra prediction is performed for one of the plurality of sub-blocks using the reference sample constructed on the basis of the current block, the intra prediction is performed after compensating a reference sample which is not neighboring to the one sub-block.

19 . An image encoding apparatus comprising an intra predictor,
wherein the intra predictor is configured to determine an intra prediction mode for a current block, to select at least one reconstructed sample line neighboring to the current block, to construct a reference sample using at least one reconstructed sample included in the at least one reconstructed sample line, and to perform intra prediction for the current block based on the intra prediction mode and the reference sample.

20 . A recording medium storing a bitstream generated by an image encoding method, the method comprising:
determining an intra prediction mode for a current block; selecting at least one reconstructed sample line neighboring to the current block; constructing a reference sample using at least one reconstructed sample included in the at least one reconstructed sample line; and performing intra prediction for the current block based on the intra prediction mode and the reference sample.

Assignees

• Electronics & Telecommunications Res Inst

Inventors

• Jun Dong San
• Lee Jin Ho
• Kang Jung Won
• Ko Hyun Suk
• Lim Sung Chang
• Lee Ha Hyun
• Cho Seung Hyun
• Kim Hui Yong
• Choi Jin Soo

Classifications

• H04N19/126

  Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers · CPC title

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title

• H04N19/159 Primary

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

• H04N19/50

  using predictive coding (H04N19/61 takes precedence) · CPC title

• H04N19/13

  Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC] · CPC title