1. A method of estimating a motion vector of a current block, the method comprising: obtaining spatial similarities between the current block and a plurality of neighboring partitions around the current block; selecting at least one of the neighboring partitions based on the obtained spatial similarities; and estimating a motion vector of the selected partition as the motion vector of the current block, wherein a size of the plurality of neighboring partitions are smaller than the size of the current block, and wherein the obtaining the spatial similarities comprises obtaining spatial similarities based on an average value of pixels of the current block and an average value of pixels of each of the neighboring partitions.