US 11,956,451 B2
Method for decoding image on basis of CCLM prediction in image coding system, and device therefor
Jangwon Choi, Seoul (KR); Jin Heo, Seoul (KR); Seunghwan Kim, Seoul (KR); Sunmi Yoo, Seoul (KR); Ling Li, Seoul (KR); and Jungah Choi, Seoul (KR)
Assigned to LG ELECTRONICS INC., Seoul (KR)
Filed by LG ELECTRONICS INC., Seoul (KR)
Filed on May 25, 2023, as Appl. No. 18/202,023.
Application 18/202,023 is a continuation of application No. 17/719,090, filed on Apr. 12, 2022, granted, now 11,706,426.
Application 17/719,090 is a continuation of application No. 17/180,474, filed on Feb. 19, 2021, granted, now 11,412,236, issued on Aug. 9, 2022.
Application 17/180,474 is a continuation of application No. 16/892,095, filed on Jun. 3, 2020, granted, now 11,012,699, issued on May 18, 2021.
Application 16/892,095 is a continuation of application No. PCT/KR2019/015253, filed on Nov. 11, 2019.
Claims priority of provisional application 62/770,835, filed on Nov. 23, 2018.
Prior Publication US 2023/0308665 A1, Sep. 28, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/186 (2014.01); H04N 19/105 (2014.01); H04N 19/136 (2014.01); H04N 19/176 (2014.01)
CPC H04N 19/186 (2014.11) [H04N 19/105 (2014.11); H04N 19/136 (2014.11); H04N 19/176 (2014.11)] 3 Claims
OG exemplary drawing
 
1. An image decoding apparatus for an image decoding, the image decoding apparatus comprising:
a memory; and
at least one processor connected to the memory, the at least one processor configured to:
obtain image information comprising prediction mode information for a current chroma block;
derive one of a plurality of cross-component linear model (CCLM) prediction modes as a CCLM prediction mode of the current chroma block, based on the prediction mode information;
derive a sample number of neighboring chroma samples of the current chroma block based on a width or height of the current chroma block and a specific value;
derive the neighboring chroma samples of the sample number;
derive down sampled neighboring luma samples related with the neighboring chroma samples and down sampled luma samples of a current luma block;
calculate CCLM parameters based on the neighboring chroma samples and the down sampled neighboring luma samples;
derive prediction samples for the current chroma block based on the CCLM parameters and the down sampled luma samples; and
generate reconstructed samples for the current chroma block based on the prediction samples,
wherein the specific value is derived as 2,
wherein the width or height of the current chroma block is N,
wherein the plurality of CCLM prediction modes include a left top LM mode, a top LM mode and a left LM mode,
wherein based on the N being less than or equal to the specific value, the sample number of the neighboring chroma samples is derived as 2N, and
wherein based on the N being greater than the specific value, the sample number of the neighboring chroma samples is derived as 4.