Influence of Tristimulus Values Correlation and Reference White in Error Propagation to CIELUV and CIELAB Color Parameters

摘要

Random errors propagation from tristimulus values to CIELUV and CIELAB color parameters has been studied considering two factors usually neglected in the literature: the correlation among tristimulus values measurements, and the associated error to the measurement of the reference white. Our study is based on experimental measurements performed by a modern spectroradiometer (SpectraScan PR-704 Photo Research), using 28 Munsell samples illuminated by 3 different luminous sources (D65, F and TL84) provided by a VeriVide color assessment cabinet. Sets of 10 measurements were made by 3 different procedures (short temporal period, large temporal period, and spatial variation), for each one of the color samples and luminous sources mentioned above. Correlation among tristimulus values reduces the error propagated to CIELUV and CIELAB color parameters in a factor up to 2.6, this effect being minimum for L~* and b~*. The errors in the tristimulus values of the reference white increase the error propagated to CIELUV and CIELAB color parameters in a factor up to 1.8. Anyway, under our experimental conditions, the instrumental errors of the a~* and b~* coordinates are lower than the visual sub-thresholds predicted by the CIE94 model in a factor about 20.