Patent ID: 7412114

Claim:
A method of generating an interpolation image, comprising: dividing a first image into a plurality of first blocks; searching a second image for a second block having a correlation with respect to one of the first blocks every first block; deriving a first motion vector between the first block and the second block; extracting a first sub block and a second sub block from the first block, the first sub block including pixels that an absolute difference value is less than a threshold, the second sub block including pixels that the absolute difference value is not less than the threshold, the absolute difference value being an absolute difference value between opposite pixels of the first block and the second block; searching for a third sub block in a region on the second image, the third sub block having a stronger correlation with respect to the second sub block than to the first sub block, said correlation being stronger than a predetermined condition, the region corresponding to a region that the absolute difference value is less than the threshold; deriving a second motion vector between the second sub block and the third sub block; copying the first sub block and the second sub block onto a third image between the first image and the second image, using the first motion vector and the second motion vector, and outputting, as said interpolation image, the third image which is between the first image and the second image, wherein searching for the second block includes computing the absolute difference value between opposite pixels of each of a plurality of block candidates of the second image and the first block every pixel, counting pixels that the absolute difference value is less than the threshold to obtain the number of pixels, and selecting as the second block one of the block candidates in a search range that the number of pixels is maximum, wherein the absolute difference value is a first absolute difference value and the threshold is a first threshold, and searching for the third sub block includes computing a second absolute difference value of opposite pixels between each of a plurality of sub block candidates of the second image and the second sub block every pixel, counting pixels in the first region that the second absolute difference value is less than a second threshold to obtain the number of pixels, counting pixels in the second region on the second image that the first absolute difference value is less than the first threshold and the second absolute difference value is less than second threshold to obtain the second number of pixels, and selecting as the third sub block one of the second sub block candidates that sum of the number of pixels and the second number of pixels is maximum in a search range, and wherein the second threshold is smaller than the first threshold.