US 12,284,340 B2
Method and device for performing image decoding on basis of intra prediction in image coding system
Sunmi Yoo, Seoul (KR); Jaeho Lee, Seoul (KR); Jangwon Choi, Seoul (KR); Jungdong Seo, Seoul (KR); and Jin Heo, Seoul (KR)
Assigned to LG ELECTRONICS INC., Seoul (KR)
Filed by LG ELECTRONICS INC., Seoul (KR)
Filed on Apr. 24, 2024, as Appl. No. 18/644,829.
Application 18/644,829 is a continuation of application No. 18/091,933, filed on Dec. 30, 2022.
Application 18/091,933 is a continuation of application No. 17/512,146, filed on Oct. 27, 2021, granted, now 11,570,431, issued on Jan. 31, 2023.
Application 17/512,146 is a continuation of application No. 16/913,731, filed on Jun. 26, 2020, granted, now 11,190,763, issued on Nov. 30, 2021.
Application 16/913,731 is a continuation of application No. 16/591,238, filed on Oct. 2, 2019, granted, now 10,757,407, issued on Aug. 25, 2020.
Application 16/591,238 is a continuation of application No. PCT/KR2018/000226, filed on Jan. 5, 2018.
Claims priority of provisional application 62/512,737, filed on May 31, 2017.
Prior Publication US 2024/0275957 A1, Aug. 15, 2024
Int. Cl. H04N 19/11 (2014.01); H04N 19/117 (2014.01); H04N 19/176 (2014.01); H04N 19/82 (2014.01)
CPC H04N 19/11 (2014.11) [H04N 19/117 (2014.11); H04N 19/176 (2014.11); H04N 19/82 (2014.11)] 4 Claims
OG exemplary drawing
 
1. An image decoding method performed by a decoding device, the method comprising:
obtaining prediction mode information for a current block from a bitstream;
deriving an intra prediction mode of an upper neighboring block of the current block and an intra prediction mode of a left neighboring block of the current block;
constructing a Most Probable Mode (MPM) list for the current block based on the intra prediction mode of the upper neighboring block and the intra prediction mode of the left neighboring block;
deriving an MPM candidate indicated by the prediction mode information among MPM candidates in the MPM list as the intra prediction mode of the current block;
deriving neighboring samples including left neighboring samples and upper neighboring samples of the current block;
deriving reference samples for prediction of a target sample among the neighboring samples, based on a position of the target sample of the current block and a prediction angle of the intra prediction mode;
determining an interpolation filter applied to the reference samples based on the intra prediction mode and a size of the current block;
deriving a predicted sample of the target sample based on the interpolation filter and the reference samples; and
generating a reconstructed picture based on the prediction sample,
wherein determining the interpolation filter applied to the reference samples based on the intra prediction mode and the size of the current block comprises:
determining whether the intra prediction mode of the current block is a directional intra prediction mode;
based on the intra prediction mode of the current block being the directional intra prediction mode, determining whether the size of the current block is smaller than a first specific value; and
based on the size of the current block being smaller than the first specific value, determining whether the prediction angle of the intra prediction mode is smaller than a second specific value,
wherein based on the size of the current block being not smaller than the first specific value, the interpolation filter is derived as a Gaussian filter,
wherein based on the size of the current block being smaller than the first specific value and the prediction angle of the intra prediction mode being smaller than the second specific value, the interpolation filter is derived as a cubic filter, and
wherein based on the size of the current block being smaller than the first specific value and the prediction angle of the intra prediction mode being not smaller than the second specific value, the interpolation filter is derived as the Gaussian filter.