>Dear Dr. Pelli,dear Maarten Hogervorst
>I would like to obtain 12-bits luminance resolution on a PC with
>Windows95 and thought about using the ISR Video Attenuator.
>I have been warned that it might be extremely difficult to address
>the LUTs on a PC. Could you give me a reference (person) on how
>to obtain 12 bits resolution on a PC? I would very much appreciate
>your advice.
>Kind regards,
>Maarten Hogervorst
>
>____________________________________________________
>Dr. Maarten A. Hogervorst
>TNO Human Factors
>Vision & Imaging, Department of Perception
>P.O. Box 23, 3769 ZG Soesterberg, The Netherlands
>Phone +31 346 356 241, Fax +31 346 353 977
>E-mail: hogervorst@...
>
the ISR Video Attenuator uses the old Apple connectors, which won't suit
your PC.
http://vision.nyu.edu/Tips/Attenuator.html
You're better off building your own, from the complete schematics given
in the original article:
D. G. Pelli and L. Zhang (1991) Accurate control of contrast on
microcomputer displays. Vision Research, 31:1337-1360.
It's not hard; the entire circuit consists of 6 resistors.
While it is true that you will need to load the CLUT, and that figuring
out how to do this may not be trivial, it isn't "extremely difficult".
It's my impression that this difficulty has already been overcome in the
Windows version of the PsychToolbox, for which you can get the source
code:
http://color.psych.ucsb.edu/psychtoolbox/win.html
good luck!
best
denis
Denis Pelli
Professor of Psychology and Neural Science at NYU