Psychtoolbox and ViSaGe

Dear List,

I am wondering whether it is possible to use the Psychophysics toolbox
together with the ViSaGe System of Cambridge Research Systems. I know
there is the Matlab toolbox from CRS but for compatibility with
another system we are using we would like to use the PTB.

Thanks for help or pointers to something to read,

Philipp
MPI Biol. Kyb., Tuebingen
Hi Philipp and Steve,

its true that VISaGe is not directly compatible, but
it probably would be possible to use it as a "slave"
display device for PTB if high redraw rates are not a
big concern.

You'd need a recent gfx-card in your PC which runs
the Windows Desktop, and the Psychtoolbox. You'd
open a normal onscreen window on that desktop display
and do all drawing into it via PTB.

Then we could add a small plugin to PTB's imaging pipeline,
which - at each Screen('Flip') - basically mirrors the output
of the normal display to the display of visage:

The plugin (written as a small Matlab M-File) would
take a "screenshot" of the PTB onscreen window,
convert that into a standard Matlab image matrix and
then use whatever functions the visage toolbox for Matlab
has to offer to copy that matlab matrix onto the visage
display and flip it onscreen there.

This is not fast - copy of image data through matlab
is a rather inefficient operation, so probably not suitable
for dynamic stimuli, but it could be completely hidden
from usercode, so a one-line setup call would be
the only needed modification to experiment scripts.

One could either readback the final image as floating
point matrix for conversion by the crs library, or -
if the low level data format of Visage and Bits++ box
are the same - let PTB do the fast conversion and
copy that over.

I don't have any experience with Visage, but this
should be doable.

Of course this only makes sense if you already have
a visage.

If you start from scratch, the Bits++ box is the
better choice for PTB. It is very well supported by PTB,
very fast, probably cheaper and may offer
most/all of what you need.

best,
-mario

--- In psychtoolbox@yahoogroups.com, "Steve Elliott" <steve.elliott@...> wrote:
>
> Dear Philipp
>
> The ViSaGe hardware is not directly compatible with Psychtoolbox
> because the proprietary real-time kernel mode drivers that we created
> for Windows XP do not support OpenGL (or DirectX, or any other
> general-purpose graphics library). This means the PTB SCREEN command
> will not be executed by ViSaGe.
>
> We have another product called Bits++ that you can use with
> Psychtoolbox: this provides 14bit luminance and colour resolution for
> analog CRT monitors and can output frame/line synchronous TTL pulses
> to trigger external equipment (see www.crsltd.com/bits++ for a little
> more technical information). The device is compatible with any
> computer graphics card that has a digital DVI output, and thanks to
> Mario's hard work over the last year, it is natively supported by
> PTB3. Please type "help bitsplusplus" at the MATLAB/PTB3 command
> prompt and look at message
> http://tech.groups.yahoo.com/group/psychtoolbox/message/8053 to find
> out more about what you can do with Bits++ and the latest Beta branch
> of Psychtoolbox-3.
>
> Regards
>
> Steve
> --
> Steven Elliott
> Cambridge Research Systems Ltd.
> www.crsltd.com
>
> --- In psychtoolbox@yahoogroups.com, "philipp.berens"
> <philipp.berens@> wrote:
> >
> > Dear List,
> >
> > I am wondering whether it is possible to use the Psychophysics toolbox
> > together with the ViSaGe System of Cambridge Research Systems. I know
> > there is the Matlab toolbox from CRS but for compatibility with
> > another system we are using we would like to use the PTB.
> >
> > Thanks for help or pointers to something to read,
> >
> > Philipp
> > MPI Biol. Kyb., Tuebingen
> >
>