1. A method for generating a predicted value of an image comprising: determining a searching scope, wherein multiple motion vectors are included in the searching scope; performing up-sampling interpolations on first reference blocks by using a first filter to obtain up-sampled first reference blocks, wherein the first reference blocks comprise reference blocks in a reference image of a current block corresponding to the motion vector in the searching scope; obtaining at least one candidate motion vector corresponding to the current block by using the up-sampled first reference blocks; performing up-sampling interpolations on second reference blocks by using a second filter to obtain up-sampled second reference blocks, wherein the second reference blocks comprise reference blocks in the reference image of the current block corresponding to the at least one candidate motion vector; and combining the up-sampled second reference blocks to generate a predicted value of the current block during image encoding or decoding.