Sphere reflectance uniformity analysis and compensation for primary color standard

The instrument for spectral diffuse reflectance and color coordinate measurement has to be calibrated by a spectral reflectance standard, so as to obtain an absolute value. Normally, the value is traced to the primary color standard or diffuse reflectance standard. The integration sphere is one of the key components in the primary color standard of China, and the reflectance nouniformity of the sphere is the biggest systematic error source of the absolute measurement result. A novel uniformity analysis method is developed basing on scanning technique with CCD array spectrometer for reducing the effect of uniformity to the primary color standard measurement. The preliminary experiment shows that the effect of sphere nouniformity can be corrected basing on the scanning data of uniformity distribution.