| 摘要 |
A motion estimating method for determining a motion vector, using a bit rate-distortion technique in image compression. The motion estimating method includes the steps of obtaining a motion vector (xo, yo) which minimizes a predetermined error function, assuming a preferred motion vector (x, y), calculating the difference (x-diff, y-diff) between (xo, yo) and (x, y), obtaining the number of bits needed to encode the x-diff and y-diff, determining a bias based on a bias model according to the bit number, obtaining a final cost function value based on the difference between a cost function value and a bias, comparing the final cost function value with a predetermined allowance limit, determining the assumed motion vector (x, y) as a motion vector for a current macroblock and updating the allowance limit by using the cost function value, if the cost function value is smaller than the predetermined allowance limit and discarding the assumed motion vector (x, y) if the cost function value is not smaller than the predetermined allowance limit. The disclosed method is successful in increasing the compression rate. |
