Patent ID: 7006571

Claim:
A method of synthesizing an interframe predicted image of a current frame from a reference image for encoding/decoding image information to produce motion vectors, comprising: a first step for calculating values of motion vectors between said interframe predicted image and said reference image for four representative points at coordinates (i,j), (i+p, j), (i, j+q), (i+p, j+q) of said interframe predicted image (where i, j, p, q are integers, the horizontal and vertical components of the motion vectors of the representative points taking the values of integral multiples of 1/k where k is the hk power of 2, and hk is a non-negative integer), a second step for calculating a motion vector of a pixel in said interframe predicted image at coordinates (x+w, y+w) by performing bilinear interpolation/extrapolation on the motion vectors of the four representative points of the interframe predicted image where the pixel sampling interval in both horizontal and vertical directions is 1 and horizontal and vertical coordinates of sampling points are obtained by adding w to integers (where w=wn/wd, wn is a non-negative integer, wd is a hw power of 2, hw is a non-negative integer and wn<wd), where said second step comprises: a third step for calculating the horizontal and vertical components of motion vector at the coordinates (i, y+w) as numerical values which are respectively integral multiples of 1/z (where z is the power of 2, and hz is a non-negative integer) by linear interpolation/extrapolation of the motion vectors of the representative points at the coordinates (i, j), (i, j+q), and for calculating the horizontal and vertical components of the motion vector at the coordinates (i+p, y+w) as values which are respectively integral multiples of 1/z (where z is the hz power of 2, and hz is a non-negative integer) by linear interpolation/extrapolation of the motion vectors of the representative points at coordinates (i+p, j), (i+p, j+q), and a fourth step for calculating the horizontal and vertical components of the motion vector of the pixel at the coordinates (x+w, y+w) as values which are respectively integral multiples of 1/m (where m is the hm power of 2, and hm is a non-negative integer) found by linear interpolation/extrapolation of two motion vectors at coordinates (i, y+w), (i+p, y+w); and a fifth step of synthesizing said interframe predicted image by calculating the pixel value of said pixel at coordinates (x+w, y+w) in said interframe predicted image using said reference image and said motion vector of said pixel at coordinates (x+w, y+w) calculated in said fourth step.