Correcting tristimulus colorimeters via spectrum-enhanced algorithm

The mismatch between spectral responses of each channel of the tristimulus colorimeter and the tristimulus value of the CIE1931-XYZ spectrum will cause systematic errors in chromaticity and luminance measurements. In the measurement of emissive displays, such as LED, OLED or micro-LED displays, spectral colorimeters are often applied to correct results measured by tristimulus colorimeters. However, the accuracy and repeatability of corrected results are affected by random noise and sampling difference. To overcome the both impacts, a spectrum-enhanced algorithm based on multi-sub-pixel sampling is introduced to correct tristimulus colorimeters. Firstly, the principle of the algorithm is presented. Secondly, simulation is conducted to verify that the accuracy and repeatability of chromaticity and luminance improve with the increase of the quantity of sub-pixels sampled. Comparative simulation and experiment are conducted for further verification in condition of sampling 8 sub-pixels and sampling one sub-pixel. The average and standard deviation of residual errors in condition of multi-sub-pixel sampling is respectively 20% and more than 70% lower than those in condition of single sub-pixel sampling. The spectrum-enhanced algorithm based on multi-sub-pixel sampling presented can effectively correct tristimulus colorimeters for high-precision chromaticity and luminance measurement of emissive displays.