# US 12,120,292 B2 · Method and device for encoding/decoding image by using geometrically changed image > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,120,292 B2 - Document ID: US12120292B2 - Status: Granted - Kind: B2 - Application number: 17/972,894 - Filed: 2022-10-25 - Published: 2023-02-09 - Granted: 2024-10-15 - Earliest claimed: 2015-11-20 - Assignees: Electronics and Telecommunications Research Institute; University-Industry Cooperation Group of Kyung Hee University - Applicants: Electronics and Telecommunications Research Institute; University-Industry Cooperation Group of Kyung Hee University - Inventors: Jung Won Kang; Hyun Suk Ko; Sung Chang Lim; Jin Ho Lee; Dong San Jun; Hui Yong Kim; Gwang Hoon Park; Jin Soo Choi; Tae Hyun Kim; Dae Young Lee; Young Su Heo - Web page: https://patentgrep.com/patent/US12120292B2 ## CPC - H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction - H04N 19/147: according to rate distortion criteria (rate-distortion as a criterion for motion estimation H04N19/567) - H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction - H04N 19/176: the region being a block, e.g. a macroblock - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A method and apparatus use a geometric modified image for video encoding/decoding. The encoding method may include: generating a geometric modified reference picture by geometrically modifying a reference picture; generating a prediction block of a current block within an encoding target picture by performing inter prediction by referencing the reference picture or the geometrically modified reference picture; and encoding inter-prediction information of the current block. ## Claims ### Claim 1 A method for encoding an image, the method comprising: determining a prediction block of a current block within an encoding target picture by performing inter prediction based on a reference picture and geometric modification information; and encoding geometric modification usage information of the current block indicating whether the geometric modification information is used for inter-prediction for the current block, wherein: a part of the reference picture is geometrically modified based on the geometric modification information, a geometrical modification of the part of the reference picture including at least one of a size modification, and a rotation modification, the geometric modification information includes a plurality of geometric parameters, the prediction block of the current block is determined based on the geometrically modified part of the reference picture, the reference picture is selected from a reference picture list and is different from the encoding target picture, and the geometric modification information is encoded by using a motion information candidate list. ### Claim 2 (depends on 1) The method of claim 1, further comprising: generating geometric modification information is obtained based on a relation between a pixel position in the encoding target picture and a pixel position in the reference picture corresponding to the pixel position in the encoding target picture. ### Claim 3 (depends on 1) The method of claim 1, wherein the prediction block is selected from either a first prediction block generated by referencing the reference picture that is not geometrically modified or a second prediction block generated by referencing the geometrically modified part of the reference picture. ### Claim 4 (depends on 3) The method of claim 3, wherein the selected prediction block is selected based on an encoding efficiency of the current block for each of the first prediction block and the second prediction block. ### Claim 5 (depends on 1) The method of claim 1, wherein the motion information candidate list includes a motion information candidate derived from a neighboring block adjacent to the current block. ### Claim 6 (depends on 1) The method of claim 1, wherein the geometric modification usage information is encoded in a symbol value corresponding to a combination of information on each prediction direction and geometric modification usage information on each prediction direction when a bi or more-directional prediction is used for generating the prediction block of the current block. ### Claim 7 (depends on 6) The method of claim 6, wherein encoding the symbol value is performed by encoding a difference value between the symbol value and a symbol value corresponding to geometric modification usage information that is previously used. ### Claim 8 A method for decoding an image, the method comprising: decoding geometric modification usage information of a current block indicating whether geometric modification information is used for inter-prediction for the current block; and when the geometric modification usage information indicates that the geometric modification information is used for inter prediction for the current block, determining a prediction block of the current block within a decoding target picture by performing inter prediction based on a reference picture and the geometric modification information, wherein: a part of the reference picture is geometrically modified based on the geometric modification information, a geometrical modification of the part of the reference picture including at least one of a size modification, and a rotation modification, the geometric modification information includes a plurality of geometric parameters, the prediction block of the current block is determined based on the geometrically modified part of the reference picture, the reference picture is selected from a reference picture list and is different from the decoding target picture, and the geometric modification information is obtained by using a motion information candidate list. ### Claim 9 (depends on 7) The method of claim 7, wherein the motion information candidate list includes a motion information candidate derived from a neighboring block adjacent to the current block. ### Claim 10 (depends on 8) The method of claim 8, wherein the geometric modification usage information is decoded in a symbol value corresponding to a combination of information of each prediction direction and geometric modification usage information on each prediction direction when a bi or more-directional prediction is used for generating the prediction block of the current block. ### Claim 11 (depends on 10) The method of claim 10, wherein decoding the symbol value comprises: decoding a difference value between the symbol value and a symbol value corresponding to geometric modification usage information that is previously used; and adding the symbol value corresponding to geometric modification usage information that is previously used to the decoded difference value. ### Claim 12 (depends on 8) The method of claim 8, wherein the geometric modification information is the plurality of geometric parameters, and comprise at least one of a motion vector, geometric size modification parameters, a geometric affine modification parameters, or geometric projection modification parameters. ### Claim 13 A non-transitory recording medium storing a bitstream that is generated by an encoding method, the encoding method comprising: determining a prediction block of a current block within an encoding target picture by performing inter prediction based on a reference picture and geometric modification information; and encoding geometric modification usage information of the current block indicating whether the geometric modification information is used for inter-prediction for the current block, wherein: a part of the reference picture is geometrically modified based on the geometric modification information, a geometrical modification of the part of the reference picture including at least one of a size modification, and a rotation modification, the geometric modification information includes a plurality of geometric parameters, the prediction block of the current block is determined based on the geometrically modified part of the reference picture, the reference picture is selected from a reference picture list and is different from the encoding target picture, and the geometric modification information is encoded by using a motion information candidate list.