Most natural images span a large range of luminance values, often a thousand-to-one and sometimes a million-to-one (Heckaman and Fairchild, 2009). This luminance range must be mapped by the visual system onto a scale of perceived gray shades (called lightness) with a range of roughly thirty-to-one (90% to 3% reflectance). For the painter who wants to represent this scene on a canvas, the challenge is a bit different. The high-range scene must be represented using pigments with a range of only thirty-to-one. Let’s begin with vision. Even without a high range in the scene, understanding the mapping of luminance onto lightness has proven elusive. But we can think of the problem as having two parts: Anchoring and scaling.

Date Published: 14 March 2013
PDF: 9 pages
Proc. SPIE 8651, Human Vision and Electronic Imaging XVIII, 865105 (14 March 2013); doi: 10.1117/12.2013205

Published in SPIE Proceedings Vol. 8651:
Human Vision and Electronic Imaging XVIII
Bernice E. Rogowitz; Thrasyvoulos N. Pappas; Huib de Ridder, Editor(s)