Motion compensating apparatus, moving image coding apparatus and method

A motion compensating apparatus comprising:

• motion compensation processing means for receiving as inputs thereof an input image and a reference image to output a motion vector between the input image and the reference image, and an estimated image which is extracted in accordance with the reference image;
• first luminance/color difference separating means for separating an input image luminance signal and an input image color difference signal from the input image;
• second luminance/color difference separating means for separating an estimated image luminance signal and an estimated image color difference signal from the estimated image;
• a first substracter for obtaining a difference between the input image color difference signal from said first luminance/color difference separating means and the estimated image color difference signal from said second luminance/color difference separating means;
• a second substracter for obtaining a difference between the input image luminance signal from said first luminance/color difference separating means and the estimated image luminance signal from said second luminance/color difference separating means;
• color difference evaluation value producing means for producing a color difference evaluation value on the basis of the output from said first subtracter;
• luminance evaluation value producing means for producing a luminance evaluation value on the basis of the output from said second subtracter;
• evaluation value calculating means for calculating an evaluation value for determination of an optimal vector on the basis of the color difference evaluation value from said color difference value producing means and the luminance evaluation value from said luminance evaluation value producing means;
• and
• vector determining means for receiving as inputs thereof the motion vector and the evaluation value for determination of an optimal vector to output as an optimal vector the motion vector, in which the evaluation value for determination of an optimal vector is minimum, out of a plurality of motion vectors which can be selected.