To achieve the foregoing, and in accordance with the purpose of the
present invention, an apparatus and method for generating refined
sub-pixel vectors for motion estimation from vector correlation values
and converged vector correlation values using quadratic approximations
respectively is disclosed. The apparatus and method includes defining a
minimum vector position value of a converged vector and then determining
a predetermined number of vector correlation samples around the minimum
vector position value. The predetermined number of vector correlation
samples provide a coarse correlation surface estimation of the minimum
vector position value. A correlation surface fitting of the predetermined
number of vector correlation samples using a quadratic approximation of
the coarse correlation surface estimation of the minimum value is then
performed. The correlation surface fitting resulting in a refined
sub-pixel minimum vector position with horizontal and vertical
components.