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Proceedings Paper

Color assimilation and contrast near absolute threshold
Author(s): John McCann
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Paper Abstract

Simultaneous Contrast and Assimilation test targets are almost always viewed at high light levels. We measured the appearances of Simultaneous Contrast, Assimilation and other spatial surrounds near absolute rod threshold. Given the very different spatial organizations of receptive fields in rod and cone vision at detection threshold, it is not obvious that these familiar cone-vision spatial effects would be observed at rod light levels. Nevertheless, the spatial experiments showed that these targets have the same changes in appearance as those observed in bright light. Our experiments used very dim candle light that was above threshold for rods and L cones, and below threshold for M and S cones. Although detection threshold experiments show very different spatial organizations for rod and cone vision, we found that spatial contrast experiments gave the same changes of appearance. Neural contrast mechanisms at the lowest end of our visual HDR range are very similar to those at the top of the range in sunlight. This is true for both chromatic and achromatic targets.

Paper Details

Date Published: 24 January 2012
PDF: 9 pages
Proc. SPIE 8292, Color Imaging XVII: Displaying, Processing, Hardcopy, and Applications, 829203 (24 January 2012); doi: 10.1117/12.912003
Show Author Affiliations
John McCann, McCann Imaging (United States)

Published in SPIE Proceedings Vol. 8292:
Color Imaging XVII: Displaying, Processing, Hardcopy, and Applications
Reiner Eschbach; Gabriel G. Marcu; Alessandro Rizzi, Editor(s)

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