8‐4: A New SDR Twilight Visual Image Display System Employing Ultra‐High‐Dynamic‐Range Image Capturing Technology aligned with Human Circadian Behavior

Perceptually natural SDR images should retain enough information for the human observer to estimate the time at which the actual HDR scene was captured. Previous experiments revealed new phenomena related to the variation in personal circadian features in daylight. In this study, we try to extend our hypothesis to twilight (mesoscopic) vision. The key idea of the confirmation process was to focus on the visual perception of full moon texture. The main result suggests that (1) Normalized Visual Percept (NVP) of twilight vision exists and is similar to that used in daylight, and furthermore (2) the former dynamic range is significantly wider than the latter, i.e., CR (contrast ratio) was more than 106:1 vs. 104:1.