# Spatial contrast sensitivity testing with attenuator

**URL:** <https://psychtoolbox.discourse.group/t/spatial-contrast-sensitivity-testing-with-attenuator/1516>\
**Category:** Uncategorized\
**Created:** [November 23, 2007, 10:03am UTC](https://psychtoolbox.discourse.group/t/spatial-contrast-sensitivity-testing-with-attenuator/1516 "2007-11-23T10:03:44Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![swaathi\_krishnan](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@swaathi\_krishnan](https://psychtoolbox.discourse.group/u/swaathi_krishnan)\
**Post date:** [November 23, 2007, 10:03am UTC](https://psychtoolbox.discourse.group/t/spatial-contrast-sensitivity-testing-with-attenuator/1516/1 "2007-11-23T10:03:44Z")

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Hi,  
  
 We are doing a project on age related changes in central and   
peripheral contrast sensitivity functions.  
 We plan to conduct monitor based contrast sensitivity experiments.   
Consequently we are trying to create a programme for measuring the   
contrast sensitivity using MATLAB. In order to increase the contrasts   
we are using Pelli-Zhang video attenuator. We had built a Pelli-Zhang   
attenuator for this purpose and the experiment monitor was calibrated   
with and without the attenuators.  
 Our problem now is in creating a colormap using the LUT files we   
have obtained after the calibrations. We have a problem in executing   
the algorithm mentioned in the article "Accurate control of contrast   
on microcomputer displays", Pelli and Zhang, Vision Research (1991),   
Vol 31 (7/8), 1337-1350.  
 We would be very grateful to you if any of can give us any   
guidelines or share any programme codes you might have designed which   
would be useful for us to overcome this problem.