US 11,889,059 B2
Encoder, decoder, encoding method, and decoding method
Jing Ya Li, Singapore (SG); Ru Ling Liao, Singapore (SG); Chong Soon Lim, Singapore (SG); Han Boon Teo, Singapore (SG); Hai Wei Sun, Singapore (SG); Che Wei Kuo, Singapore (SG); Kiyofumi Abe, Osaka (JP); Takahiro Nishi, Nara (JP); and Tadamasa Toma, Osaka (JP)
Assigned to PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA, Torrance, CA (US)
Filed by Panasonic Intellectual Property Corporation of America, Torrance, CA (US)
Filed on Jul. 28, 2022, as Appl. No. 17/875,965.
Application 17/875,965 is a continuation of application No. 17/307,336, filed on May 4, 2021, granted, now 11,438,580.
Application 17/307,336 is a continuation of application No. PCT/JP2019/047114, filed on Dec. 3, 2019.
Claims priority of provisional application 62/777,500, filed on Dec. 10, 2018.
Prior Publication US 2022/0385891 A1, Dec. 1, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/105 (2014.01); H04N 19/136 (2014.01); H04N 19/159 (2014.01); H04N 19/176 (2014.01); H04N 19/52 (2014.01); H04N 19/80 (2014.01)
CPC H04N 19/105 (2014.11) [H04N 19/136 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/52 (2014.11); H04N 19/80 (2014.11)] 2 Claims
OG exemplary drawing
 
1. An encoding method comprising:
generating a prediction image based on a first parameter, a second parameter, a third parameter, and a fourth parameter that are derived in a bi-directional optical flow (BDOF) process; and
encoding a current block using the generated prediction image,
wherein
the first parameter, the second parameter, the third parameter, and the fourth parameter are derived on a subblock-by-subblock basis, the current block being divided into subblocks, and a size of each of the subblocks being 4×4;
the first parameter is derived based on the following expression:
Σ[i,j]∈Ωabs(Ix1+Ix0);  [Math. 1]
the second parameter is derived based on the following expression:
Σ[i,j]∈Ωabs(Iy1+Iy0);  [Math. 2]
the third parameter is derived based on the following expression:
Σ[i,j]∈Ω(sign(Ix1+Ix0)×(I1−I0)); and  [Math. 3]
the fourth parameter is derived based on the following expression:
Σ[i,j]∈Ω(sign(Iy1+Iy0)×(I1−I0)),  [Math. 4]
where:
Ω indicates a set of relative pixel positions;
[i, j] indicates a relative pixel position in the set Ω defined by a horizontal position i and a vertical position j;
Ix0 indicates a horizontal gradient value at a first pixel position in a first horizontal gradient image, Ix1 indicates a horizontal gradient value at the first pixel position in a second horizontal gradient image, Iy0 indicates a vertical gradient value at the first pixel position in a first vertical gradient image, and Iy1 indicates a vertical gradient value at the first pixel position in a second vertical gradient image, the first pixel position being determined based on a relative pixel position [i, j], the first horizontal gradient image, the second horizontal gradient image, the first vertical gradient image, and the second vertical gradient image corresponding to the current block;
I0 indicates a pixel value at the first pixel position in a first interpolated image corresponding to the current block;
I1 indicates a pixel value at the first pixel position in a second interpolated image corresponding to the current block;
the abs function outputs an absolute value of an argument; and
the sign function outputs a sign of an argument.