06-12-2018 дата публикации
Номер: US20180352263A1
Принадлежит:
The present principles proposes an invertible and low complexity inverse gamut mapper that preserves invariance of colors near the white point. 1. A method for processing color image data representing colors of an original color gamut , wherein the method comprises an inverse-color gamut mapping step in the course of which color image data , represented by a 2D point M belonging to a triangle ABC , is mapped to a mapped color image data of an output color gamut , said triangle ABC representing the original color gamut in a chromaticity diagram and centered on the white point O of the original color gamut , said mapped color image data of the output color gamut being represented by a 2D point M′ belonging to a triangle A′B′C′ representing the output color gamut in the chromaticity diagram , wherein the inverse-color gamut mapping step comprises sub-steps of:{'sub': λ0', 'λ0', 'λ0', '0', 'λ0', 'λ0', 'λ0, 'determining a triangle ABCin the chromaticity diagram by applying an homothety to the triangle ABC, said homothety being centered on the white point O and using a scaling factor λ, said triangle ABCrepresenting a preserved color gamut in which the color image data remain unchanged;'}determining three angular sectors in the chromaticity diagram, each delimited by two lines starting from the white point O and joining one of the vertices A, B or C of the triangle ABC, and computing a 2×2 matrix for each of those three angular sectors according to the triangle ABC;computing intermediate coordinates of the 2D point M, assuming this 2D point M belongs to one of the three angular sectors, by multiplying the coordinates of the 2D point M by the matrix relative to said angular sector;if those intermediate coordinates are positive values and if their sum is lower or equal to 1, then the 2D point M belongs to the current angular sector, otherwise other intermediate coordinates are computed by considering another angular sector;{'sub': λ0', 'λ0', 'λ0', 'λ0', 'λ0', 'λ0', 'λ0', 'λ ...
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