US 12,407,860 B2
Image coding method based on secondary transform, and device therefor
Moonmo Koo, Seoul (KR); Seunghwan Kim, Seoul (KR); and Jaehyun Lim, Seoul (KR)
Assigned to LG Electronics Inc., Seoul (KR)
Filed by LG Electronics Inc., Seoul (KR)
Filed on Apr. 25, 2024, as Appl. No. 18/645,950.
Application 18/645,950 is a continuation of application No. 18/198,382, filed on May 17, 2023, granted, now 12,003,774.
Application 18/198,382 is a continuation of application No. 17/592,301, filed on Feb. 3, 2022, granted, now 11,689,745, issued on Jun. 27, 2023.
Application 17/592,301 is a continuation of application No. 17/329,749, filed on May 25, 2021, granted, now 11,277,638, issued on Mar. 15, 2022.
Application 17/329,749 is a continuation of application No. PCT/KR2019/017892, filed on Dec. 17, 2019.
Claims priority of provisional application 62/781,594, filed on Dec. 18, 2018.
Prior Publication US 2024/0298031 A1, Sep. 5, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G06V 10/00 (2022.01); H04N 19/11 (2014.01); H04N 19/124 (2014.01); H04N 19/132 (2014.01); H04N 19/159 (2014.01); H04N 19/176 (2014.01); H04N 19/18 (2014.01); H04N 19/61 (2014.01)
CPC H04N 19/61 (2014.11) [H04N 19/11 (2014.11); H04N 19/124 (2014.11); H04N 19/132 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/18 (2014.11)] 4 Claims
OG exemplary drawing
 
1. An image decoding method performed by a decoding apparatus, the method comprising:
obtaining residual information from a bitstream;
deriving quantized transform coefficients for a target block based on the residual information;
deriving transform coefficients for the target block by dequantizing the quantized transform coefficients;
deriving modified transform coefficients for the target block based on an inverse non-separable transform for the transform coefficients;
deriving residual samples for the target block based on an inverse primary transform for the modified transform coefficients; and
generating a reconstructed picture based on the residual samples for the target block,
wherein the inverse non-separable transform is performed through a matrix operation of the transform coefficients for a top-left area of the target block and a transform kernel matrix,
wherein the transform kernel matrix is selected based on a transform index from a transform set,
wherein the transform set is derived based on a mapping relationship according to an intra prediction mode applied to the target block,
wherein the modified transform coefficients are two-dimensionally arranged according to a row-first direction based on the intra prediction mode being a horizontal mode in a left direction with respect to a top-left diagonal direction, and
wherein the modified transform coefficients are two-dimensionally arranged according to a column-first direction based on the intra prediction mode being a vertical mode in a right direction with respect to the top-left diagonal direction.