US 12,225,228 B2
Image coding method, image decoding method, image coding apparatus, and image decoding apparatus
Viktor Wahadaniah, Singapore (SG); Chong Soon Lim, Singapore (SG); Sue Mon Thet Naing, San Jose, CA (US); Hai Wei Sun, Singapore (SG); Takahiro Nishi, Nara (JP); Hisao Sasai, Osaka (JP); Youji Shibahara, Osaka (JP); Kyoko Tanikawa, Osaka (JP); Toshiyasu Sugio, Osaka (JP); Kengo Terada, Osaka (JP); and Toru Matsunobu, Osaka (JP)
Assigned to SUN PATENT TRUST, New York, NY (US)
Filed by Sun Patent Trust, New York, NY (US)
Filed on Dec. 19, 2023, as Appl. No. 18/544,808.
Application 14/074,179 is a division of application No. 13/660,245, filed on Oct. 25, 2012, granted, now 8,913,665, issued on Dec. 16, 2014.
Application 18/544,808 is a continuation of application No. 18/114,371, filed on Feb. 27, 2023, granted, now 11,902,568.
Application 18/114,371 is a continuation of application No. 17/389,783, filed on Jul. 30, 2021, granted, now 11,622,128, issued on Apr. 4, 2023.
Application 17/389,783 is a continuation of application No. 16/813,994, filed on Mar. 10, 2020, granted, now 11,115,677, issued on Sep. 7, 2021.
Application 16/813,994 is a continuation of application No. 16/399,437, filed on Apr. 30, 2019, granted, now 10,631,004, issued on Apr. 21, 2020.
Application 16/399,437 is a continuation of application No. 14/074,179, filed on Nov. 7, 2013, granted, now 10,321,152, issued on Jun. 11, 2019.
Claims priority of provisional application 61/552,848, filed on Oct. 28, 2011.
Prior Publication US 2024/0121429 A1, Apr. 11, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/527 (2014.01); H04N 19/513 (2014.01); H04N 19/52 (2014.01); H04N 19/58 (2014.01)
CPC H04N 19/527 (2014.11) [H04N 19/513 (2014.11); H04N 19/52 (2014.11); H04N 19/58 (2014.11)] 1 Claim
OG exemplary drawing
 
1. An image decoding method of decoding each block among blocks of pictures, the image decoding method comprising:
selecting a collocated picture from a plurality of referable reference pictures, the collocated picture being different from a current picture that includes a current block to be decoded;
deriving a candidate for motion vectors of the current block, from a first motion vector of a first block included in the collocated picture, the first block being located in the collocated picture at (i) a position corresponding to a position bottom right adjacent to the current block in the current picture or (ii) when the position bottom right is not available, a position corresponding to a position at a center of the current block in the current picture;
adding the derived candidate to a list of motion vector candidates;
selecting, based on an index, one candidate that includes a second motion vector from the list of motion vector candidates; and
decoding the current block using (i) the second motion vector included in the selected one candidate and (ii) a reference picture of the current block,
wherein the deriving includes:
determining whether a collocated reference picture of the first block is a long-term reference picture or a short-term reference picture, the collocated reference picture being a reference picture referred to by the first block included in the collocated picture;
determining whether the reference picture of the current block is a long-term reference picture or a short-term reference picture;
deriving the second motion vector so as to be the same as the first motion vector without scaling based on a temporal distance in the case of determining that (i) the collocated reference picture of the first block is a long-term reference picture and (ii) the reference picture of the current block is a long-term reference picture; and
deriving the second motion vector from the first motion vector by scaling based on a temporal distance in the case of determining that (i) the collocated reference picture of the first block is a short-term reference picture and (ii) the reference picture of the current block is a short-term reference picture,
wherein the scaling is based on a ratio of temporal distance calculated by using (i) a difference between a Picture Order Count (POC) assigned to the current picture and the POC assigned to the reference picture and (ii) a difference between the POC assigned to the collocated picture and the POC assigned to the collocated reference picture, and
wherein the POC is a sequential number assigned for each of the current picture, the reference picture, the collocated picture, and the collocated reference picture based on display order.