Contrast inconstancy across changes in polarity
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Updated: Oct 17, 2026

Merging Ion Concentration Polarization between Juxtaposed Ion Exchange Membranes to Block the Propagation of the Polarization Zone
Published on: February 23, 2017
1Department of Psychology, University College London, UK. c.benton@ucl.ac.uk
Abstract:
In this study, we show that negative polarity noise patterns appear to have a higher contrast than positive polarity noise patterns with identical expected Fourier amplitude spectra. This demonstrates a failure of contrast constancy over changes in pattern polarity. An examination of local contrast measures shows that negative polarity noise has a wider distribution of local contrast values than positive polarity noise. We propose that the difference in apparent contrast between the two patterns may be based upon spatial non-linearities in the combination of local contrast measures.
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