IMAGE CODING APPARATUS, IMAGE CODING METHOD, AND IMAGE CODING SYSTEM

Prediction directions for cost calculation are reduced by preferentially selecting a direction in which a prediction pixel is generated by direct copy without filtering from among intra prediction directions to perform intra prediction. In addition to the roughly selected prediction direction, an amount of processing is reduced while deterioration of coding efficiency is prevented through comparison with preferentially selected prediction, such as DC prediction and planar prediction, and selection of second-stage prediction direction focused on a vicinity of roughly selected prediction direction.