Method and apparatus for calibrating a color measurement instrument in the field

A non-transitory computer-readable medium storing instructions which, when executed by a processor of a fielded color measurement instrument comprising a plurality of color channels, cause the processor to perform operations, the operations comprising:

• obtaining a first response of the fielded color measurement instrument to light emitted by a fielded light emitting device, wherein the fielded color measurement instrument has not been calibrated to measure a color of the light emitted by the fielded light emitting device;
• obtaining a calibration matrix, wherein the calibration matrix contains measurements made by the fielded color measurement instrument of a first plurality of lights emitted by the fielded light emitting device and measurements made by a spectroradiometer of a second plurality of lights emitted by a reference light emitting device of a same make and model as the fielded light emitting device, wherein the spectroradiometer is located remotely from the fielded color measurement instrument;
• obtaining a second response of the fielded color measurement instrument to the light emitted by the fielded light emitting device;
• and
• converting the second response into a triplet that corresponds to a Commission Internationale de L'éclairage XYZ color space by multiplying the second response by the calibration matrix.

A fielded color measurement instrument comprising a plurality of color channels, the fielded color measurement instrument comprising:

• a processor;
• and
• a non-transitory computer-readable medium storing instructions which, when executed by the processor, cause the processor to perform operations comprising:
• obtaining a first response of the fielded color measurement instrument to light emitted by a fielded light emitting device, wherein the fielded color measurement instrument has not been calibrated to measure a color of the light emitted by the fielded light emitting device;
• obtaining a calibration matrix, wherein the calibration matrix contains measurements made by the fielded color measurement instrument of a first plurality of lights emitted by the fielded light emitting device and measurements made by a spectroradiometer of a second plurality of lights emitted by a reference light emitting device of a same make and model as the fielded light emitting device, wherein the spectroradiometer is located remotely from the fielded color measurement instrument;
• obtaining a second response of the fielded color measurement instrument to the light emitted by the fielded light emitting device;
• and
• converting the second response into a triplet that corresponds to a Commission Internationale de L'éclairage XYZ color space by multiplying the second response by the calibration matrix.