IMAGE CODING APPARATUS AND IMAGE CODING METHOD

An image coding apparatus includes an approximating element having plural different prediction techniques to approximate, a value of a target pixel to be coded with reference to values of peripheral pixels surrounding the target pixel; a holding element which holds information about ranks of the prediction techniques, the ranks obtained upon processing of the pixel preceding the target pixel; a determining element computing an error between each of approximate values obtained by the prediction techniques and that of the target pixel, selecting one of the prediction techniques for the target pixel based on the computer error, and performing the selection by preferentially referencing the rank information if the error is within a predetermined tolerance; and a coding element which codes the value of the target pixel using the approximate value obtained by the selected prediction technique.