Scaling and Color in Natural Images
Dan Ruderman
Scale invariance is the most universal property found in natural images.
In this talk I will begin by summarizing our evidence for scaling as
evidenced by the power spectrum. I will then present a more strict
definition in terms of higher-order statistics and show that they
too scale, giving a deeper and much richer meaning to natural image
scaling. In the second part I present our recent data on predicted
retinal photoreceptor response statistics to natural images. We find
that once an appropriate metric space for cone responses is chosen that
principal components analysis provides more than just the second-order
decorrelation it guarantees. This "optimal" linear transformation
appears similar to the blue-yellow and red-green opponent processes
found both psychophysically and physiologically. Finally, the consequences
of scale invariance to spatio-chromatic decorrelation will be illuminated.
Back to the Natural Scenes Meeting Agenda.