The image coding apparatus is constituted comprising an atom extraction
section 109 for acquiring position data indicating the positions of atoms
of prediction residual data in macroblocks, for each of the macroblocks;
and a variable length encoding section 113 for determining the frequency
of occurrence distribution of the position data in the macroblocks to be
encoded, in accordance with the number of atoms of prediction residual
data present in the macroblocks, and for performing arithmetic coding of
the position data on the basis of the frequency of occurrence
distribution thus determined. An improvement in the efficiency of the
entropy coding of the atom parameters of Matching Pursuits coding is
therefore feasible.