Check/match the luminance of cogent-created images
1 view (last 30 days)
Show older comments
I've got someone else's code that creates two circular visual stimuli, which are very similar to pie charts. They are drawn while the code is running (i.e. they aren't just image files being loaded from a drive) using the Cogent toolbox, specifically the cgarc command.
I want to be able to match the luminance of these two visual stimuli. Is there any Matlab code that can be used to report or match the luminance of two stimuli that are drawn 'on-line' rather than loaded from a file?
Thanks Rob
0 Comments
Answers (1)
Image Analyst
on 1 Sep 2014
If you (or the code) drew them, then you know the color of them and you can make sure they're the same.
2 Comments
Image Analyst
on 1 Sep 2014
Yes, exactly. If the RGB are the same, you know they "should" be the same, however you know from checking your monitor screen with a lightmeter or radiometer that the light emitted everywhere on the screen isn't the same even when it's supposed to be, because of side lighting by the fluorescent or LED lights. So how are you going to take that into account? Take a picture of a uniform screen and divide the image by that? No, as you should know, cameras have shading, mostly due to the lens which means they'll be darker at the side than they should be. As you can see, it can be quite a complicated issue to do what you're trying to do and that's why calibrated viewing environments and monitors are expensive to buy and take some effort to calibrate. They're not "just plug it in and it works" like other arbitrary monitors that don't have good luminance control. For really good, high quality, calibratable monitors, try Barco: http://www.barco.com/en/Products-Solutions/Displays-monitors-workstations
See Also
Categories
Find more on Pie Charts in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!