Patent ID: 6785333
Filing Date: 2004-08-31
Classification: H04N

Abstract:
A method of coding a motion vector comprising the steps of:(a) performing an affine motion estimation to obtain affine motion parameters; (b) converting the affine motion parameters to a predetermined number of translational motion vectors; and (c) coding the difference between the converted translational motion vectors of a current block and the converted translational motion vectors of a previous block, prior to step (c), further comprising the step of quantizing the translational motion vectors in step (b) to fixed-point numbers having a predetermined accuracy further comprising the step of determining a predetermined pixel range for each translational motion vector of the current block and obtaining an accuracy &PHgr; for each pixel value in the predetermined pixel range, the accuracy &PHgr; producing the smallest value in min&varphi;&epsi;Î &it;{MSE&it;(&varphi;)+Î»&it;â€ƒ&it;Bits&it;(&varphi;)}among a set Î  of accuracies, where QP is a quantization interval used in coding an image, &lgr; is a constant determined based on the quantization interval QP, MSE(&PHgr;) denotes the mean square sum of a differential signal between the current block and a preceding motion-compensated block when translational motion vectors of the current block are represented with an accuracy &PHgr;, and Bits (&PHgr;) denotes the number of bits used to code the translational motion vector of the current block with an accuracy &PHgr;.