| 摘要 |
In apparatus for processing television signals for transmission, motion estimation is carried out by calculating 10 a correlation function C(x, y) for motion vectors (x, y) using information from signals representing a previous picture and the current picture. The best integer-pixel estimate (X, Y) for the motion vector is determined 12 from the calculated values of C(x, y). From the calculated values of C(x, y) the region relative to (X, Y) in which the best sub-integer-pixel estimate (X', Y') of the motion vector is to be found is determined. Subsequently values of the correlation functions C(x, y) for those sub-integer pixel motion vectors which are in the said region are calculated 18 and compared 18 so as to find (X', Y'). Since only the sub-integer estimates of the motion vector within the region identified from the integer-pixel estimates are calculated, the only previous-picture pixels which need to be accessed for the sub-integer pixel search are those which would be needed if a motion compensated version of the previous picture were required. Furthermore, only four streams of interpolated pixels need be generated and corresponding mean absolute error values calculated and compared. <IMAGE> |
