Method and system for color point calibration of light source projector
AssigneeBarco N.V.
InventorsArnout Robert Leontine Vetsuypens, Peter Eric Rita Janssens
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Abstract
The present invention relates to image projection and provides a method and system for performing color calibration of light sources and correction towards a color target, for example a whitepoint target. The calibration and correction considers the ambient temperature and that the projector output has an arbitrary dimming level. The correction can be made automatic and can be performed by an operator in the field by pressing a button.
Claims20
A method for correcting driving currents to reach a color point target for a multiple of primary colour light sources in an imaging system having a light source controller, the method comprising the steps of:
- defining a color point target,
- obtaining a measured ambient temperature,
- obtaining tristimulus values of the light from the primary colour light sources,
- providing initial driving current values which are incoming driving current values of the light sources to the light source controller, wherein the initial driving current values are provided for a reference ambient temperature,
- for each of the light sources:
- calculating driving current values for the light sources as a function of at least one of the tristimulus values of the light sources, at the reference ambient temperature,
- adapting the driving current values based on the difference between the measured ambient temperature and the reference ambient temperature,
- correcting the driving current values with alpha factors, wherein the alpha factors are the dimming levels for each light source for reaching the color point target, and which depend on a relation between the obtained tristimulus values and the color point target, and the function of the at least one of the tristimulus values,
- and applying corrected driving current values which are outgoing driving current values to the primary colour light sources.
A system for correcting laser driving currents to reach a color point target for a multiple of primary colour light sources in an imaging system having a light source controller, comprising:
- means for defining a color point target,
- means for receiving a measured ambient temperature,
- means for receiving tristimulus values of the light from the primary colour light sources,
- means for providing initial laser driving current values, which are incoming laser driving current values of the light sources to the light source controller, wherein the initial laser driving current values are provided for a reference ambient temperature,
- and for each of the light sources:
- means for obtaining current conversion values between incoming laser driving currents and outgoing laser driving currents;
- wherein the light sources are adapted to receive the outgoing laser driving currents,
- means for calculating the outgoing laser driving current values for the light sources as a function of at least one of the tristimulus values of the light sources, at the reference ambient temperature based on the incoming laser driving current values,
- means for adapting the laser driving current values based on the difference between the measured ambient temperature and the reference ambient temperature,
- means for correcting the laser driving current values with alpha factors, wherein the alpha factors are the dimming levels for each light source for reaching the color point target,
- and which depend on a relation between the obtained tristimulus values and the color point target, and the function of the at least one of the tristimulus values,
- and means for applying corrected laser driving current values as outgoing laser driving current values to the primary colour light sources.
A system for correcting driving currents to reach a color point target for a multiple of primary colour light sources in an imaging system having a light source controller, comprising:
- means for defining a color point target,
- means for receiving a measured ambient temperature,
- means for receiving tristimulus values of the light from the primary light sources,
- means for providing initial driving current values of the light sources to the light source controller, wherein the initial driving current values are provided for a reference ambient temperature,
- and for each of the light sources:
- means for calculating driving current values for the light sources as a function of at least one of the tristimulus values of the light sources, at the reference ambient temperature,
- means for adapting the driving current values based on the difference between the measured ambient temperature and the reference ambient temperature,
- means for correcting the driving current values with alpha factors, wherein the alpha factors are the dimming levels for each light source for reaching the color point target,
- and which depend on a relation between the obtained tristimulus values and the color point target, and the function of the at least one of the tristimulus values,
- and means for applying corrected driving current values to the primary light sources,
- and further comprising a projector adapted so that any dependencies on the ambient temperature are controlled using an internal light sensor.
Dependencies are inferred from the claim text.