A statistical explanation of the effect of luminance on photopic visual acuity of speckled images
M.J. Buades, J.M. Artigas, A. Felipe and J. Malo
Journal of Optics. Vol. 26, 4, pp 175-176 (1995)

Abstract

The intensity of a polarized speckle pattern obeys a negative exponential probability density function. This distribution implies a signal-to-noise-ratio (SNR) unity since the standard deviation equals the mean intensity. However, if the logarithmic response of the retinal photoreceptors is taken into account, the first order statistics of the pattern is transformed in such a way that the SNR becomes a function of the mean intensity. The results developed here are closely connected with the masking effect of speckle in vision experiments. In particular, it contributes to explain why the resolving power of the human visual system with speckled imagery decreases as the mean luminance increases.


Key Words: Perceptual non-linearities. Speckle noise.

References: 7


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