Next generation personalized display systems employing adaptive dynamic-range compression techniques to address diversity in individual circadian visual features

Perceptually natural standard-dynamic-range (SDR) images reproduced under normal viewing conditions should retain enough information for the human observer to estimate the time at which the actual high-dynamic-range (HDR) scene was captured without recourse to artificial information. Currently, both global- and local-tone mapping operators (TMOs) seem to have comparable levels of performance. Therefore, we first consider the constraints created in the actual human visual system by eye movement, and buttress a hypothesis with a demonstration. We briefly review the imperceptible illuminance effects yielded by the personal circadian clock suggested by chronophysiological research and other related effects, because our previous study suggested that the characteristics of the human visual system dynamically varies depending on the individual's circadian pattern. Finally, we conduct two psychophysical experiments based on the hypothesis that the human visual system employs several global TMOs at the first stage for information compression that depend on individual-circadian-visual-features (ICVF). The results suggest that (1) no participant can perceive actual-capture-time (ACT) and (2) sensitive observers can discriminate reproduced images based on virtual-shooting-time (VST) effects induced by different types of global TMOs. We also discover that the VST-based discrimination differs widely among people, but most are unaware of this effect as evidenced by daily conversations. It is crucial to realize perceptually natural, without recourse to artificial information, standard-dynamic-range (SDR) image reproduction that allows estimation the actual-capture-time (ACT) of real high-dynamic-range (HDR) scenes. Experiments suggest that (1) discrimination of luminance-tones involves virtual-shooting-times (VSTs), not ACTs, and (2) that this discrimination differs widely among people but most are unaware of this effect as evidenced by daily conversations. image