METHOD AND DEVICE FOR COLOUR IMAGE ENCODING AND DECODING Russian patent published in 2019 - IPC H04N19/186 H04N19/36 H04N19/80 H04N5/355 

FIELD: calculating; counting.

SUBSTANCE: invention relates to the computer equipment. Method of encoding a color image having colour components (Ec) comprises the steps of: obtaining a luminance component (L) based on: modulation values (Ba) from the colour image (Y) brightness; scaled brightness obtained by dividing the brightness (Y) of the colour image by the modulation value (Ba); luminance components (L) by applying a nonlinear function to the scaled brightness such that the luminance component (L) dynamics are reduced compared to the scaled luminance dynamics; obtaining two chroma components (C1, C2), based on: a coefficient (r(L(i)), which depends on the pixel value (i) of the brightness component (L(i)) and the brightness value (Y(i)) having same pixel location (i) in colour image; intermediate colour component (E'c) by multiplying each colour component (Ec) by a coefficient (r(L(i)); and two chromaticity components (C1, C2) obtained from said intermediate colour component (E'c); and encoding luminance (L) and two chrominance components (C1, C2).

EFFECT: technical result is providing backward compatibility of images with SDR.

23 cl, 9 dwg, 1 tbl