Analytical simulator of color mixing process on large display surfaces

The authors have previously proposed a calculation model for the color mixing process considering human color vision and the pixel structures of a display surface. Using this model, we can calculate the viewing distance at which observers distinguish the pixel structure, but we cannot understand a particular image intuitively. Therefore, this paper proposes an analytical simulator which enables us to understand how mixed colors are perceived without actually manufacturing a large display unit. It also supplies the output of the resulting image according to the viewing distance and the structure of the display surface. First, the simulator draws test samples of the display surface that reproduce the pixel structures. Next, the spatial-frequency characteristics of the R, G and B pixel dots on the display surface are calculated. Thirdly, the visual characteristics in the spatial-frequency domain are realized for each color as a modulation transfer function of a low pass filter, where the viewing distance is used as a parameter and the bandwidth and attenuation slope of each color are constant. Fourthly, in the spatial-frequency domain, the display surface characteristics are multiplied with the characteristics of human vision for each color. Finally, the simulator converts the spatial-frequency characteristics to spatial characteristics, and composes the appearance of each color to show the resulting color mixing image. Using this simulator, we conducted simulations under conditions with different viewing distances. As a result, we found that the longer the viewing distance becomes, the less recognizable are the pixel dots and they look to have a more uniform, mixed color. These results agree qualitatively with the appearance of images on the screens of actual large display units and prove the validity of our simulator.