METHOD AND APPARATUS FOR ENCODING IMAGE

摘要

PURPOSE: A method and an apparatus for encoding an image are provided to increase DFD zero tree encoding efficiency through a band adaptive preprocessing procedure of a transformed wavelet coefficient. CONSTITUTION: A method for encoding an image includes three steps. A first step is to find a mean of a coefficient absolute value by each band and an absolute value of each coefficient in a wavelet pyramid structure. A second step is to subtract each absolute value of coefficients, which is in each band and found in the first step from a mean value of the coefficient absolute value of each band. A third step is to sequentially encode according importance a position of each coefficient biased with the mean of the coefficient absolute value of each band and a size information in the steps and output a bit streams that are aligned according to the importance. An apparatus includes a band adaptive preprocessing part(402) biasing each coefficient by each band and a zero tree encoding part(403) outputting a bit stream which is aligned according to importance.