Background:

I had an idea that simulating photographic dynamic range compression
with realistic scene parameters would yield photorealistic renderings.

Not to my surprise NASA has done some more advanced research on this area.
Here's an abstract from IEEE TRANSACTIONS ON IMAGE PROCESSING:

A Multiscale Retinex for Bridging the Gap Between
Color Images and the Human Observation of Scenes

Direct observation and recorded color images of
the same scenes are often strikingly different because human
visual perception computes the conscious representation with
vivid color and detail in shadows, and with resistance to spectral
shifts in the scene illuminant. A computation for color images
that approaches fidelity to scene observation must combine dynamic


tonal rendition. In this paper, we extend a previously designed
single-scale center/surround retinex to a multiscale version that
achieves simultaneous dynamic range compression/color
consistency/ lightness rendition. This extension fails to produce good
color rendition for a class of images that contain violations of
the gray-world assumption implicit to the theoretical foundation
of the retinex. Therefore, we define a method of color restoration
that corrects for this deficiency at the cost of a modest dilution
in color consistency. Extensive testing of the multiscale retinex
with color restoration on several test scenes and over a hundred
images did not reveal any pathological behavior.


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Kari Kivisalo                                  http://www.kivisalo.net

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