1. An image processing apparatus comprising: sum-of-absolute-difference calculation means for calculating a sum of absolute differences between pixel values of pixels in a block of interest which includes a plurality of pixels and corresponds to a pixel of interest in a first image and pixel values of pixels in a reference block which corresponds to a reference pixel in a second image, the pixels in the reference block having a same arrangement as that of the pixels in the block of interest, and the second image being displayed at a time different from when the first image is displayed; first comparison means for comparing sums of absolute differences calculated by the sum-of-absolute-difference calculation means and determining a minimum sum of absolute differences among the sums of absolute differences; motion vector estimation means for estimating a motion vector for the pixel of interest using the pixel of interest and the reference pixel having the minimum sum of absolute differences, which is obtained by the first comparison means; motion-compensated image generation means for generating a motion-compensated image by using pixel values of the pixels in the first image as pixel values of corresponding pixels in the motion-compensated image according to motion vectors for the pixels in the first image; first cumulatively adding means for cumulatively adding sums of absolute differences calculated when motion vectors for pixels in the first image are obtained, the motion vectors corresponding to the pixels in the motion-compensated image; and interpolation-image generation means for generating an interpolation image by mixing the pixels in the first image and corresponding pixels in the motion-compensated image according to a cumulative-sum result obtained by the first cumulatively adding means, one of the pixels in the first image corresponding to one of the pixels in the motion-compensated image.