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

摘要

An image coding method comprising: obtaining current signals to be coded of each of the processing units of the image; generating a binary signal by performing binarization on each of the current signals to be coded; selecting a context for each of the current signals to be coded from among a plurality of contexts; performing arithmetic coding of the binary signal by using coded probability information associated with the context selected in the selecting; and updating the coded probability information based on the binary signal, wherein, in the selecting, the context for the current signal to be coded is selected, as a shared context, for a signal which is included in one of a plurality of processing units and has a size different from a size of the processing unit including the current signal to be coded.

主权项

1. An image coding method of compression-coding an image including a plurality of processing units having mutually different sizes, said image coding method comprising:
obtaining current signals to be coded of each of the processing units of the image; generating a binary signal by performing binarization on each of the current signals to be coded; selecting a context for each of the current signals to be coded from among a plurality of contexts; performing arithmetic coding of the binary signal by using coded probability information associated with the context selected in said selecting; and updating the coded probability information associated with the context selected in said selecting, based on the binary signal generated in said generating, wherein a first shared context is set in advance, wherein, in said selecting, the first shared context is selected as the context for the current signal to be coded in the case where a size of the processing unit which includes the current signal to be coded is a block size of 16×16, and in the case where the size of the processing unit which includes the current signal to be coded is a block size of 32×32, and wherein, in said selecting, a dedicated context is selected as the context for the current signal to be coded in the case where the size of the processing unit which includes the current signal to be coded is smaller than the block size of 16×16.