Limits of HDR in Humans
John J. McCann, Alessandro Rizzi · 2011
This chapter describes measurements on humans of the effects of veiling glare on the appearance of the same test targets. It explains that camera glare limits the range of luminances falling on the camera sensor plane. Human glare is caused by Tyndall scattering by macromolecules in the intraocular media, reflections from the whitish blind spot, as well as the layers of neurons between the lens and the sensors. The chapter describes the range of discrimination and the corresponding range of retinal luminances. It deals with the measurement of the observed appearance for both 4scalesBlack and 4scalesWhite test targets. Recently, there has been a lot of interest in digital tone scale maps that convert captured scene luminance to ideal renditions for humans. Statistically the best tone scale is a straight line that starts at magnitude estimate 100 and goes to 1, because it has the lowest average error. Controlled Vocabulary Terms brightness; lasers; light scattering