US 11,856,224 B2
Image coding method based on secondary transform and device therefor
Moonmo Koo, Seoul (KR); Jaehyun Lim, Seoul (KR); Seunghwan Kim, Seoul (KR); and Mehdi Salehifar, Seoul (KR)
Assigned to LG Electronics Inc., Seoul (KR)
Filed by LG Electronics Inc., Seoul (KR)
Filed on May 12, 2022, as Appl. No. 17/743,187.
Application 17/743,187 is a continuation of application No. 17/337,148, filed on Jun. 2, 2021, granted, now 11,425,421.
Application 17/337,148 is a continuation of application No. PCT/KR2020/000035, filed on Jan. 2, 2020.
Claims priority of provisional application 62/787,356, filed on Jan. 1, 2019.
Prior Publication US 2022/0272383 A1, Aug. 25, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/61 (2014.01); H04N 19/11 (2014.01); H04N 19/122 (2014.01); H04N 19/124 (2014.01); H04N 19/129 (2014.01); H04N 19/132 (2014.01); H04N 19/159 (2014.01); H04N 19/176 (2014.01); H04N 19/18 (2014.01)
CPC H04N 19/61 (2014.11) [H04N 19/11 (2014.11); H04N 19/122 (2014.11); H04N 19/124 (2014.11); H04N 19/129 (2014.11); H04N 19/132 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/18 (2014.11)] 3 Claims
OG exemplary drawing
 
1. An image decoding method performed by a decoding apparatus, the method comprising:
receiving information regarding quantized transform coefficients from a bitstream;
deriving transform coefficients of a target block based on a dequantization for quantized transform coefficients of the target block;
deriving modified transform coefficients of the target block based on an inverse non-separable secondary transform using a transform kernel matrix 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 deriving of the modified transform coefficients comprises:
deriving 16 modified transform coefficients by applying the transform kernel matrix to 8 transform coefficients in a 4×4 region of the target block,
wherein 65 directional modes among intra prediction modes are symmetric with respect to mode 34 which is an intra prediction mode in the top-left diagonal direction, and
wherein based on an intra prediction mode applied to the target block being one of mode 2 to the mode 34 in the left direction with respect to the mode 34, the 16 modified transform coefficients are two-dimensionally arranged in the 4×4 region according to a row-first direction.