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Does anyone have any experience with luminance changes in a visual display?

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Adam Vilanova-Goldstein
Adam Vilanova-Goldstein on 13 Dec 2020
Commented: Image Analyst on 15 Dec 2020
I am a visual cognitive psychologist and I use Matlab and PsychToolBox for some visual search experiments. I am attempting to change the luminance of black stimuli at random intervals. I have considered using a grey as the baseline and then changing the color to make it darker or lighter randomly but have been unable to get the color to change. Any suggestions on how I should think about this?
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Image Analyst
Image Analyst on 14 Dec 2020
When you mean "color" you mean the brightness (intensity) of a gray scale image, right? Not the color like a non-gray/tinted RGB image?
Also, when you say "random intervals" do you mean intervals of gray level, or time intervals?

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Answers (2)

Matt Gaidica
Matt Gaidica on 13 Dec 2020
'Value' is, I believe, the same as 'luminance' in your case. If so, you could create images based on HSV values and change the value variable dynamically.
h = zeros(200,200);
s = zeros(200,200);
v = ones(200,200);
RGB1 = hsv2rgb(h,s,v*0.3);
RGB2 = hsv2rgb(h,s,v*0.5);
RGB3 = hsv2rgb(h,s,v*0.8);
close all
montage({RGB1,RGB2,RGB3},'Size',[1,3]);
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Image Analyst
Image Analyst on 13 Dec 2020
You should probably calibrate your displays with this device:
In addition, there are ASTM guidelines for viewing (target brightesses, surround brightness, clothing, room brightness, etc.) that you may want to look at.

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