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

FIELD: physics.

SUBSTANCE: image encoding method using arithmetic encoding comprises: performing arithmetic encoding over the first flag that indicates, whether the absolute value of the target coefficient in the target coefficient block is greater than 1. The target coefficient block is obtained by dividing the target encoding block, which is obtained by converting the input image into coefficients in the frequency domain; and performing arithmetic encoding over the second flag, which indicates, whether the absolute value is greater than 2. When performing arithmetic coding over the first flag and performing arithmetic coding over the second flag, it is determined, whether the immediately preceding coefficient block that was encoded immediately before the block of target coefficients includes a coefficient having an absolute value greater than the threshold value and the context to be used in arithmetic coding over the first flag, and the context to be used in arithmetic coding over the second flag, is chosen based on the definition result.

EFFECT: reducing the amount of processing, while simultaneously suppressing deterioration in coding efficiency.

11 cl, 64 dwg