December 2006
Volume 6, Issue 13
OSA Fall Vision Meeting Abstract  |   December 2006
Some observations on the pedestal effect or dipper function
Author Affiliations
  • G. Bruce Henning
    The Sensory Research Unit, Department of Experimental Psychology, Oxford University, Oxford OX1 3UD, United Kingdom
  • Felix A. Wichmann
    Max-Planck Institute for Biological Cybernetics
Journal of Vision December 2006, Vol.6, 50. doi:
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      G. Bruce Henning, Felix A. Wichmann; Some observations on the pedestal effect or dipper function. Journal of Vision 2006;6(13):50. doi:

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      © ARVO (1962-2015); The Authors (2016-present)

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The pedestal effect is the large improvement in the detectabilty of a sinusoidal “signal” grating observed when the signal is added to a masking or “pedestal” grating of the same spatial frequency, orientation, and phase. We measured the pedestal effect in both broadband and notched noise - noise from which a 1.5-octave band centred on the signal frequency had been removed. Although the pedestal effect persists in broadband noise, it almost disappears in the notched noise. Furthermore, the pedestal effect is substantial when either high- or low-pass masking noise is used. We conclude that the pedestal effect in the absence of notched noise results principally from the use of information derived from channels with peak sensitivities at spatial frequencies different from that of the signal and pedestal. The spatial-frequency components of the notched noise above and below the spatial frequency of the signal and pedestal prevent the use of information about changes in contrast carried in channels tuned to spatial frequencies that are very much different from that of the signal and pedestal. Thus the pedestal or dipper effect measured without notched noise is not a characteristic of individual spatial-frequency tuned channels.

Henning, G. B. Wichmann, F. A. (2006). Some observations on the pedestal effect or dipper function [Abstract]. Journal of Vision, 6(13):50, 50a,, doi:10.1167/6.13.50. [CrossRef]
 This research was supported by The Max-Planck Society and the Wellcome Trust

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