Subject: Re: CVNet - An LCD monitor for research in vision
From: Michael Bach <[email-masked]>
To: CVNet CVNet <[email-masked]>
Date: Mon, 26 Sep 2011 09:40:29 +0200

Dear fellow CVNetters interested in visual display units:

I bought a Samsung SyncMaster 2233 on Danko's recommendation. Yes, nice monitor, but: This one and _all_ LCDs I looked at and heard about suffer from luminance artifacts due to asymmetric hi-lo switching delays. Just display a checkerboard (even number of checks, and centered) and reverse check contrast: there should be no net change in mean luminance, but there is a brief transient artifact. Depending on contrast, this can be a brief increment or decrement. Easily seen by placing a white sheet moderately close to the display and observing it while the stimulus reverses, ideally at about 10 reversals per second.

Such pattern-reversal stimuli (which are unfortunately often termed "flicker stimuli" in the fMRI literature) thus actually do flicker, totally unacceptable for many of my applications.

Best, Michael.
-- 
Prof. Michael Bach PhD, Ophthalmology, University of Freiburg, Killianstr. 5, 79106 Freiburg, Germany.
President of ISCEV <http://www.iscev.org/>
Visual illusions:  <http://michaelbach.de/ot/>

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