Neutral White And Observer Metamerism Of Display Systems

Neutral white plays an important role in the color vision research and the standardization of color-related industries such as lighting,surface color,and image technology.How to determine the range of neutral white for different applications has been a hot research topic in recent years.Typically,it requires to perform a large number of visual matching experiments.However visual experiments inevitably introduce the influence of the observer metamerism.The color management system for imaging devices have recently paid more attention to the observer metamerism,and there is an urgent need to develop effective methods to evaluate this phenomenon.This is particularly important for the display design industry.With above in mind,the goals of the research are the neutral white and the observer metamerism for the display systemThree experiments were carried out to study neutral white.In the first experiment,neutral white matching experiment was carried out using two monitors having different characteristics with two luminance levels and four starting points.The results showed a significant difference between the two displays,and the luminance level to have little impact on the neutral white results.In the second experiment,a display that can be set with many different white points was also studied.Two display characteristics models,sRGB and GOG,were used to obtain different starting points.The results revealed that the white point also had little influence on neutral white results,and the difference in the starting point need to be large enough to have a significant effect on the neutral white.Experiment 2 was conducted to design a display with different primary sets using a multi-channel LED light source,and found that primary sets have a significant effect on the neutral white results.The other research topic was to investigate the observer metamerism using the multiple primary sets display.Using the results in experiment 3(spectral data of the designed multiple primary sets display)and the newly proposed individual chrometric observer model,a simulation color matching experiment was performed,and then the actual color matching experiment was performed to obtain visual data.Experiments have found that blue and green primaries are more important than red primaries when designing a new display.The degree of observer metamerism caused by switching red primaries is much smaller than the other two primaries.It was found the primary set with the peak wavelengths of 450,525,and 665 nm was able to increase the sRGB color gamut by 72.1%in the CIE 1931 chromaticity diagram,which was found to have a strong correlation to the color volume of wide color gamut displays,while introducing the minimal color mismatch to the white point of the reference display and observer metamerism.The results revealed that CIE 1931 CMFs for observer metamerism evaluation should not be used,due to its own problems in the shortwave range,causing observer metamerism to be overestimated.It is proposed to use CIE 2006 CMFs with field of view to be close to the actual field of view in the experiment.The present results on neutral white and observer metamerism enable us to understand some basic principles of human color vision,such as the differences between individual human beings and evaluation of the observer's color matching function.It provides knowledge for future personalized color management,and guideline for the design of new displays with wider color gamut while keep minimum observer metamerism.