Patent ID: 9124896
Filing Date: 2015-09-01
Classification: A61B,H04N

Abstract:
1. A motion vector decoding method for decoding a motion vector of a current block in a moving picture, the method comprising: a neighboring block specification step of specifying three neighboring blocks, the three neighboring blocks being located in a neighborhood of the current block and having been already decoded; a first judgment step of judging whether or not each of the three neighboring blocks has been decoded using a motion vector of another block; a second judgment step of judging whether or not a reference picture referred to in the decoding of the current block is the same as each of a reference picture referred to in the decoding of the three neighboring blocks; a different motion vector determining step of determining a different motion vector of each of the three neighboring blocks based on a result of the first judgment step; a prediction step of deriving a predictive motion vector of the current block using different motion vectors of the three neighboring blocks based on a result of the second judgment step; a decoding step of decoding a coded motion vector to obtain a decoded difference motion vector of the current block; and a motion vector recovering step of recovering the motion vector of the current block by adding the decoded difference motion vector of the current block and the predictive motion vector, wherein, in the different motion vector determining step of determining a different motion vector of each of the three neighboring blocks, (1) a motion vector, which is calculated from the motion vector of the other block and which is used in performing a decoding process on a neighboring block of the three neighboring blocks, is determined as a different motion vector of the neighboring block when it is judged in the first judgment step that the neighboring block has been decoded using the motion vector of the other block, and (2) a motion vector, which is detected for the neighboring block and which is used in performing a decoding process on the neighboring block, is determined as a different motion vector of the neighboring block when it is judged in the first judgment step that the neighboring block has not been decoded using the motion vector of the other block, wherein, in the prediction step of deriving a predictive motion vector of the current block, (1) when it is judged in the second judgment step that three neighboring blocks refer to the same reference picture as the current block, the predictive motion vector of the current block is set to a median of three motion vectors of the three neighboring blocks, and (2) when it is judged in the second judging step that only one of the three neighboring blocks refer to the same reference picture as the current block, the predictive motion vector of the current block is set to be a motion vector of the only one neighboring block having the same reference picture as the current block.