Method and apparatus for controlling a variable-colour light source

1. A control device for controlling a variable-colour light source, the variable-colour light source comprising a plurality of individually controllable colour light sources; where the control device is responsive to an input signal, which input signal is indicative of a colour and a brightness, where the control device comprises a control unit for generating, respective activation signals for each of the individually controllable colour light sources; which control unit comprises predetermined calibration data indicative of at least one calibration colour vector in a predetermined colour space and at least one brightness response mapping for each of the individually controllable colour light sources, wherein the control unit is configured to generate the activation signals from the input signal in relation to the predetermined calibration data;

wherein the control device is configured

to obtain an input colour vector indicative of the received colour and brightness;

to determine at least one component of the input colour vector along at least one of the calibration colour vectors; and

to apply a corresponding one of the brightness response mapping resulting in a corresponding one of the activation signals.

2. A control device according to claim 1 , wherein the calibration data is indicative of at least two colour vectors in a predetermined colour space for each of the individually controllable colour light sources.

3. A control device according to claim 2 , further comprising storage means for storing said calibration data.

4. A control device according to claim 3 , further comprising an input interface for receiving said calibration data.

5. A control device according to claim 4 , wherein the calibration data includes, a first calibration parameter indicative of at least one of a measured hue and a measured saturation value of the individually controllable light source for each of the individually controllable light sources.

6. A control device according to claim 5 , wherein the calibration data includes, second and third calibration parameters indicative of a brightness scaling function of the individually controllable light source for each of the individually controllable light sources.

7. A control device according to claim 6 , wherein the control device further comprises an input interface for receiving a temperature signal; and wherein the control unit is further adapted to compensate the generated activation signals responsive to said temperature signal.

8. A control device according to claim 7 , wherein the individually controllable light sources include light emitting diodes.

9. A method of controlling a variable-colour light source, the variable-colour light source comprising a plurality of individually controllable colour light sources; the method comprising:

storing predetermined calibration data indicative of at least one set of colour values for each of the individually controllable light sources,

receiving an input signal indicative of a colour and a brightness; and

generating, responsive to the received input signal, respective activation signals for each of the individually controllable colour light sources;

wherein generating includes generating the activation signals from the input signal and from the predetermined calibration data by;

obtaining an input colour vector indicative of the received colour and brightness;

determining at least one component of the input colour vector along at least one of the calibration colour vectors; and

applying a corresponding one of the brightness response mapping resulting in a corresponding one of the activation signals.

10. A method of calibrating a variable-colour light source, the variable-colour light source comprising a plurality of individually controllable colour light sources, the method comprising:

providing a calibration input signal indicative of a colour and a brightness to the variable-colour light source;

receiving a colorimetric measurement signal indicative of a set of measured colour values emitted by the variable-colour light source in response to the input signal,

determining calibration data from the calibration input signal and the received calorimetric measurement;

storing at least one set of colour values for each of the individually controllable light sources, said set of colour values being storing indicative of said calibration data;

receiving an input signal indicative of a colour and a brightness; and

generating, responsive to the received input signal, respective activation signals for each of the individually controllable colour light sources;

wherein generating includes generating the activation signals from the input signal and from the predetermined calibration data by:

obtaining an input colour vector indicative of the received colour and brightness;

determining at least one component of the input colour vector along at least one of the calibration colour vectors; and

applying a corresponding one of the brightness response mapping resulting in a corresponding one of the activation signals.