80‐4: Human Visual System Uses Just a Few Transfer Functions Depending on Various Environments to Realize Normalized Visual Percept: Investigation Using Real Photographic Images

We investigate global tone mapping operators (GTMOs) that convert physical stimuli in various real HDR environments (i.e., luminance contrast ratio (CR) is up to approx. 10 5 :1) into normalized visual percept (NVP) by actually comparing real scenes with reproduced photographic images. Subjective test results suggest that the images reproduced by our proposed method are successfully converted into SDR (i.e., CR is approx. 10 2 :1). We also demonstrate that these NVPs recorded in SDR images can be re‐converted into LDR images (i.e., CR is approx. 10:1) while preserving natural tone.