Unit for and method of motion estimation and image processing apparatus provided with such motion estimation unit

The motion estimation unit (100) comprises a block-matcher (102) for calculating a start motion vector (110) by minimizing a predetermined cost function as a matching criterion for the block (116) of pixels with a further block ofpixels (122) of a further image (120). The motion estimation unit (100) further comprises an optical flow analyzer (104) for calculating an update motion vector (111) based on the start motion vector (110) and which is designed tofind the most appropriate set of optical flow equations corresponding to respective pixels of the block (116) of pixels. This is achieved by analyzing gradient vectors of optical flow equations for pixels of the block (116) of pixels. Finally the selector 106 of the motion estimation unit (100) selects the motion vector (126) by comparing thestart motion vector (110) with the update motion vector (111).