A device according to embodiments may comprise an acquisition unit, an arrangement unit, a calculating unit, and a processing unit. The acquisition unit may acquire candidate vectors from among corresponding vectors which have been calculated for each candidate block around the target block. The arrangement unit may arrange particles around each candidate block indicated by each of the acquired candidate vectors while using the target block as an origination, and arrange particle vectors while using the target block as an origination. The calculating unit may calculate a correlation between a pixel value of the target block and a pixel value of each block defined by each of the particles, and give a weight depending on the calculated correlation to each of the particle vectors. The processing unit may obtain the corresponding vector for the target block based on the weight calculated for each of the particle vectors.