System gamma as a function of image- and monitor- dynamic range

TitleSystem gamma as a function of image- and monitor- dynamic range
Publication TypeJournal Article
Year of Publication2015
AuthorsKane D, Bertalmío M
JournalJournal of Vision
Abstract
System gamma is the end-to-end exponent that describes the relationship between relative luminance values at capture and the reproduced image. The system gamma preferred by subjects is known to vary with the background luminance condition and the image in question. We confirm the previous two findings using an image database with both high and low dynamic range images (from 102 to 107 ), but also find that the preferred system gamma varies with the dynamic range of the monitor (OLED vs CRT). We find that the preferred system gamma can be predicted in all conditions and for all images by a simple model that searches for the value that best flattens the lightness distribution, where lightness is modeled as a power-law of onscreen luminance. To account for the data, the exponent must vary with the viewing condition. The method presented allows the inference of lightness perception in natural scenes without direct measurement and makes testable predictions for how lightness perception varies with the viewing condition and the distribution of luminance in a scene.