Image coding method, image decoding method, image coding apparatus, and image decoding apparatus

Abstract

An image coding method, comprising: subtracting a prediction signal from the input image signal for each coding unit, thereby generating respective prediction error signals; performing orthogonal transform and quantization on a corresponding one of the prediction error signals for each transform unit, eventually generating quantization coefficients; and coding pieces of management information indicating a structure of the transform units and the quantization coefficients into a tree structure. Each of the transform units corresponds to a corresponding one of leaf nodes in the tree structure. In the coding, for each leaf node, management information and a quantization coefficient are coded, eventually generating a coded signal in which the coded management information and the coded quantization coefficient are arranged in succession for each leaf node.