US 12,244,860 B2
Method for coding image on basis of secondary transform and device therefor
Moonmo Koo, Seoul (KR); Seunghwan Kim, Seoul (KR); Mehdi Salehifar, Seoul (KR); and Jaehyun Lim, Seoul (KR)
Assigned to LG Electronics Inc., Seoul (KR)
Filed by LG Electronics Inc., Seoul (KR)
Filed on Sep. 1, 2023, as Appl. No. 18/241,441.
Application 18/241,441 is a continuation of application No. 17/671,788, filed on Feb. 15, 2022, granted, now 11,792,430.
Application 17/671,788 is a continuation of application No. 17/327,246, filed on May 21, 2021, granted, now 11,297,347, issued on Apr. 5, 2022.
Application 17/327,246 is a continuation of application No. PCT/KR2019/017900, filed on Dec. 17, 2019.
Claims priority of provisional application 62/782,285, filed on Dec. 19, 2018.
Prior Publication US 2023/0412843 A1, Dec. 21, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/60 (2014.01); H04N 19/124 (2014.01); H04N 19/159 (2014.01); H04N 19/176 (2014.01); H04N 19/18 (2014.01); H04N 19/70 (2014.01); H04N 19/96 (2014.01)
CPC H04N 19/60 (2014.11) [H04N 19/124 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/18 (2014.11); H04N 19/70 (2014.11); H04N 19/96 (2014.11)] 3 Claims
OG exemplary drawing
 
1. An image decoding method performed by a decoding apparatus, the method comprising:
obtaining residual information, a transform index, and information on an intra prediction mode from a bitstream;
deriving transform coefficients for a target block based on the residual information; and
deriving modified transform coefficients based on an inverse non-separable transform for the transform coefficients,
wherein the deriving the modified transform coefficients comprises:
determining a transform set based on a mapping relationship according to the intra prediction mode applied to the target block;
selecting a transform kernel matrix, based on the transform index, from among two transform kernel matrices comprised in the transform set; and
deriving the modified transform coefficients by performing the inverse non-separable transform based on the transform kernel matrix,
wherein the transform index is decoded based on a context adaptive binary arithmetic coding (CABAC) and by:
deriving, based on context sets, context information of a syntax element for the transform index, the context sets including a first context set and a second context set;
decoding, based on the context information, bins of the syntax element for the transform index, the bins including a first bin and a second bin; and
deriving, based on the decoded bins, a value of the syntax element for the transform index,
wherein (i) based on a tree type of the target block being a dual tree type, the context information is derived based on the first context set, and (ii) based on the tree type of the target block being a single tree type, the context information is derived based on the second context set,
wherein the first context set comprises (i) first context information for the first bin of the syntax element for the transform index and (ii) second context information for the second bin of the syntax element for the transform index, and
wherein the second context set comprises (i) third context information for the first bin of the syntax element for the transform index and (ii) fourth context information for the second bin of the syntax element for the transform index.