Method and device for coding successive images

A method of coding successive images, comprising

• defining (600) a search area in a reference image, from which search area the block to be coded in the present image is searched;
• computing (602) the cost function of each motion vector candidate, which motion vector candidate determines the motion between the block to be coded and the candidate block in the search area;
• coding (614) the block to be coded by using the motion vector candidate giving the lowest cost function value;
• characterized in that in the computation (602) of the cost function
• number-theoretic transform is performed (604) for the block to be coded;
• number-theoretic transform is performed (606) for the candidate block;
• multiplication is performed (608) between the block to be coded and the transformed candidate block;
• correlation between the block to be coded and the candidate block is formed (610) by performing inverse transform of number-theoretic transform for the result of the multiplication;
• and
• the correlation formed is used (612) in the computation of the cost function.