Colleagues, we would like to use an LCD or DLP projector to present
very brief stimuli (single frame duration) to our subjects. Our
stimulus presentation software works perfectly on a CRT monitor and a
CRT projector, but we have been unable to successfully sync any of
the several LCD projectors that we have tried (from NEC, Proxima, and
Epson) -- instead, some images are only partially presented, or are
missed altogether. (I do realize that LCDs also have other
drawbacks, such as delays and long decay rates, etc., but these are
acceptable drawbacks for purpose. However, we absolutely need
consistency in the duration of presentation from stimulus to
stimulus.)
It appears that at least some (possibly all?) LCD projectors only use
the sync from the computer to initially select -- from its preset
frame rates -- the one frequency that is closest to that of the
computer. From then on, the projector runs at this approximate frame
rate, but is not actually synced to the computer. Tech support at
Epson has verified that this is the case, and the documentation from
Proxima implies that its LCD projectors do the same.
Can anyone provide any information on LCD projectors that DO actually
use the sync from the computer to control the frame presentation? Or
do all LCD projectors operate in this pseudo-synced manner? In the
past, I have used a DLP projector from InFocus that did correctly
sync. Is this a general difference between the way in which LCD and
DLP projectors operate?
Any help that you can provide is greatly appreciated.
Thanks,
Paul
-- =============================================================== Paul Dassonville, Ph.D. Assistant Professor Tel. 541-346-4956 (office) Dept. of Psychology Tel. 541-346-4097 (lab) 1227 University of Oregon Fax. 541-346-4911 Eugene, OR 97403-1227 mailto:prd@darkwing.uoregon.edu ===============================================================--------- About this list: http://www.visionscience.com/vsList.html
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