Motion compensating apparatus, moving image coding apparatus and method
The present invention provides a motion compensating apparatus which is capable of enhancing the overall coding efficiency by taking the amount of coded information used to code a motion vector as well as the sum of difference absolute values of estimated differences into consideration in order to determine an optimal vector. The motion compensating apparatus includes: a motion compensation processing unit for outputting a motion vector between an input image and a reference image, and an estimated image which is extracted from the reference image in accordance with the motion vector; a unit for calculating the sum of difference absolute values, as a distortion amount calculating unit, to obtain a distortion amount between the input image and the estimated image; a vector value coding unit for receiving the motion vector to code the motion vector thus inputted thereto to output a vector coded amount; and an optimal vector determining unit for receiving the motion vector, the distortion amount and the vector coded amount to obtain, for all of a plurality of motion vectors to be evaluated, an evaluation function calculated from the distortion amount and the vector coded amount to output as an optimal vector the motion vector in which the evaluation function exhibits a minimum value.
1. 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.
2. The motion compensating apparatus according to claim 1 , wherein said evaluation value calculating means comprises an adder for adding the color difference evaluation value from said color difference evaluation value producing means and the luminance evaluation value from said luminance evaluation value producing means to each other to obtain a total evaluation value, and wherein said vector determining means receives as inputs thereof said motion vector and a total addition value as the total evaluation value to output as an optimal vector the motion vector, in which said total evaluation value is minimum, out of a plurality of motion vectors which can be selected.