IMAGE CODING METHOD, IMAGE DECODING METHOD, IMAGE CODING APPARATUS, IMAGE DECODING APPARATUS, AND IMAGE CODING AND DECODING APPARATUS

摘要

An image coding method using arithmetic coding. The method includes: performing arithmetic coding on a first flag (greater1_flag) that indicates whether or not an absolute value of a target coefficient in a target coefficient block is greater than 1 (S701); and performing arithmetic coding on a second flag (greater2_flag) that indicates whether or not the absolute value is greater than 2 (S702). In the arithmetic coding on the first flag and the arithmetic coding on the second flag, it is determined whether or not an immediately-prior coefficient block that has been coded immediately prior to the target coefficient block includes a coefficient having an absolute value greater than a threshold value (S711). Based on a result of the determination, respective contexts to be used in the arithmetic coding on the first and second flags are selected (S712).