Patent ID: 8004209

Claim:
A method of controlling a temporal variation of light emitted by an illumination system ( 65 ) from light having a start color point ( 14 , S) to light having a target color point ( 12 , T, T 1 , T 2 ), the start color point ( 14 , S) and target color point ( 12 , T, T 1 , T 2 ) comprising start and target color coordinates, respectively, in a first color space (XYZ, RGB vid , RGB ill ) which is perceptually non-uniform, the method comprising the steps of: converting the start and target color coordinates to converted start and target color coordinates, respectively, in a second color space (Lab, Lch) which is a color space perceptually more uniform to the human visual system than the first color space (XYZ, RGB vid ), generating an intermediate color point ( 34 , I 1 , I 2 ) having converted intermediate color coordinates which are located on a transition-path (p, p′) within the second color space (Lab, Lcd) from the converted start color coordinates to the converted target color coordinates, an intermediate distance (d) between the converted start color coordinates and the converted intermediate color coordinates not being larger than a threshold distance ( 26 ), converting the converted intermediate color coordinates from the second color space (Lab, Lch) to intermediate color coordinates in the first color space (XYZ, RGB vid , RGB ill ), and altering the light emitted by the illumination system ( 65 , 70 ) from the start color point ( 14 , S) to the intermediate color point ( 34 , I 1 , I 2 ).