1. A method for generating an interpolated frame, the method comprising: calculating a plurality of motion vectors; calculating a temporal matching difference corresponding to a target motion vector of a current block by performing a motion estimation on the current block, wherein calculating the temporal matching difference is performed during or after calculating the plurality of motion vectors; deriving a spatial relationship result according to the target motion vector and motion vectors corresponding to a plurality of neighboring image blocks, wherein deriving the spatial relationship result is performed after calculating the target motion vector; deriving an adjusted spatial relationship result according to the temporal matching difference and the spatial relationship result; and generating the interpolated frame according to the target motion vector and the adjusted spatial relationship result.