FIELD: data processing.
SUBSTANCE: present invention relates to lossless coding. Image coding method comprises the steps of: performing a first coding, which performs orthogonal transformation and quantisation; and performing second coding performed by using any of intra-prediction mode to perform intra-prediction using a pixel outside the block to be coded, and DPCM mode for performing differential pulse code modulation (DPCM) processing on a pixel-by-pixel basis, the image coding method further comprising an information coding step for indicating whether decoding corresponding to the second coding is performed using the intra prediction mode or using the DPCM mode.
EFFECT: technical result is higher compression efficiency when coding an image by selecting a coding mode.
19 cl, 14 dwg
