IMAGE ENCODING METHOD, IMAGE DECODING METHOD, IMAGE ENCODING DEVICE AND IMAGE DECODING DEVICE Russian patent published in 2017 - IPC H04N19/00 

FIELD: data processing.

SUBSTANCE: invention relates to encoding and decoding images and performing arithmetic encoding and arithmetic decoding. Said result is achieved by using an image encoding method for encoding an image on a block-by-block basis, which comprises steps of: selecting, for each of a plurality of sub-blocks included in a target encoding block and each of which includes a plurality of coefficients, a context for performing arithmetic encoding on a parameter indicating target encoding coefficient included in sub-block, from a set of contexts corresponding to said sub-block based on a reference coefficient; and performing arithmetic encoding with respect to parameter indicating target encoding coefficient using probabilistic information on selected context, wherein set of contexts corresponds to sum of (i) a value which indicates a position in horizontal direction of sub-block in target encoding block, and (ii) a value which indicates a position in vertical direction of sub-block in target encoding block.

EFFECT: technical result consists in improvement of efficiency of encoding and decoding due to selection of target coefficient in encoding block.

19 cl, 45 dwg