Degradation of sensory signal.

<p>Here we illustrate degradation of the image signal in the eye. The <i>original signal</i> is a portion of an unaltered standard test image. The <i>blurred signal</i> is computed with the blur function measured at 30° eccentricity of the human eye <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003761#pcbi.1003761-Navarro1" target="_blank">[50]</a>. The <i>observed signal</i> (also called the raw sensory signal) simulates the noisy response of cone photoreceptors in a square lattice by adding white gaussian noise to the blurred signal.