In recent years, the effects of light pollution have become significant, and the need for image reproduction of a faithful and preferred starry sky has increased. Previous studies have analyzed the relationships between the luminance, size, and color temperature of stars and the fidelity and nature of their appearance, as well as color perception. This study examines the depth perception of stars. We consider starry sky images as a set of “small-field light sources” that can be viewed as point light sources with minimal viewing angles. Our goal was to experimentally elucidate the cues for depth perception. In our experiments, observers viewed two points of different sizes, luminances, and color temperatures and selected the one perceived to be in front to confirm the relationship between the three depth cues of retinal image; size, light attenuation, and color, and their association with depth perception. Results confirmed that retinal image size and light attenuation were relevant for a small-field light source. Results also suggest that the interaction between retinal image size and light attenuation may be explained by retinal illuminance. However, the effect of color was small, and the point with higher saturation was more likely to be perceived in front, when the hue was close to that of the point.
In this study, the preferred correlated color temperature (CCT) of the television was evaluated according to the CCT change of lighting. In the experiment, the laboratory was set up by considering five ambient lighting CCT conditions between 2500K and 6300K. In each environment, the CCT of the TV was changed from 4000K to 11500K, and an experiment was conducted to select the most preferred TV CCT. In general, it was preferred when the CCT of the TV was changed considering the CCT of the ambient light, compared to the viewing environment in which the TV was watched in one environment regardless of the CCT of the ambient light. If the CCT of the light decreases, the CCT of the display should also be lowered. Especially in low-color lighting environments, such as incandescent lights, when the TV's CCT is lowered, the white part of the image appears to be ‘real’ white and the images were more preferred.