Why luminance discrimination may be better than detection.
D004192:Discrimination, Psychological / Q000502:physiology*; D006801:Humans; D008027:Light; D008954:Models, Biological; D010783:Photometry; D011594:Psychometrics; D012684:Sensory Thresholds / Q000502:physiology; D013997:Time Factors; D014796:Visual Perception / Q000502:physiology*