1. A motion compensation interpolation device, comprising: an adaptive weighting unit, for receiving at least an input frame that comprises a plurality of blocks, allocating an interpolation block partially overlapping K adjacent blocks and comprising at least one target pixel to be interpolated, receiving K vectors corresponding to the K adjacent blocks and calculating K weighting values based on a size of the interpolation block and a first position of the target pixel; and a blending unit, for receiving K pixel values from a preceding or subsequent frame and generating pixel an interpolation value of the target pixel according to the K weighting values and the K pixel values; wherein K>=2 and the K pixel values are associated with the K vectors and the target pixel.