US 12,238,292 B2
Image decoding method using context-coded sign flag in image coding system and apparatus therefor
Sunmi Yoo, Seoul (KR); Jin Heo, Seoul (KR); Jungah Choi, Seoul (KR); and Seunghwan Kim, Seoul (KR)
Assigned to LG Electronics Inc., Seoul (KR)
Filed by LG Electronics Inc., Seoul (KR)
Filed on Nov. 7, 2023, as Appl. No. 18/387,610.
Application 18/387,610 is a continuation of application No. 17/894,741, filed on Aug. 24, 2022, granted, now 11,849,120.
Application 17/894,741 is a continuation of application No. 17/436,207, granted, now 11,451,783, issued on Sep. 20, 2022, previously published as PCT/KR2020/003049, filed on Mar. 4, 2020.
Claims priority of provisional application 62/813,662, filed on Mar. 4, 2019.
Prior Publication US 2024/0089451 A1, Mar. 14, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/00 (2014.01); H04N 19/132 (2014.01); H04N 19/159 (2014.01); H04N 19/176 (2014.01); H04N 19/196 (2014.01)
CPC H04N 19/132 (2014.11) [H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/196 (2014.11)] 14 Claims
OG exemplary drawing
 
1. An image decoding method, performed by a decoding apparatus, comprising:
receiving residual information for a current block;
deriving a context index increment for a sign flag representing a sign of a current residual coefficient of the current block;
deriving a context index for the sign flag based on the context index increment;
decoding the sign flag based on a context model for the sign flag indicated by the context index;
deriving the current residual coefficient based on the sign flag;
deriving a residual sample based on the current residual coefficient; and
generating a reconstructed picture based on the residual sample,
wherein the context index increment for the sign flag is derived based on a sign flag of a residual coefficient decoded prior to the current residual coefficient in the current block, and
wherein the residual information includes information on an absolute value of a transform coefficient level at a scanning position.