On Wed, 20 Sep 2000, Matthew Pilgrim wrote:
> Dear all,
> I have been using the ARToolkit for windows with a USB camera and a standard
> graphics card/monitor for sometime now but would like to move on to use a
> HMD to develop AR applications similar to that shown by Mark Billinghurst
> and co. at SIGGRAPH2000. We have converted a lot of the toolkit to run in a
> MFC window under Windows 95/NT/2000 (I maybe able to supply this to
> interested parties!) and would like some advise on the following:
I would love to get an MFC version of ARToolKit for the main download
page. Our own efforts in this area have been slow :(
> 1) Most of the applications I have seen have been running on an SG where a
> small view of the AR scene is shown in a window on the monitor and a full
> screen version piped to the Glasstron HMD. Is this a function of the
> graphics card/driver or is it done via software? We have a Hercules graphics
> card with s-video out but are only capable of viewing the image either via
> the HMD or the monitor but not both together.
Yes - the SGI O2 allows you to just select a VGA portion of the screen ot
output as composite or S-video. I'm not aware of any PC graphics card with
However if you get a VGA->NTSC (or PAL) convertor you should be able to
see your main monitor and a external NTSC (or PAL) monitor/HMD. Basically
you put the convertor between your PC and Monitor and it splits off a
separate video signal.
> 2) ARToolkit documentation suggests that you can use (in theory) any camera
> supported by Video for Windows. So if I buy a video capture card that has
> an s-video in port and a tiny TV camera and connect them together I will
> then be dependent on their being a correct driver available, is this
> correct? Has anyone done this?
This is correct. We've done it with the Asus V6800 Delux card. This has
video in and out. The current version with the video i/o is the V7700
> 3) As mentioned earlier I have a USB camera (Logitech) working but this is
> limited to 320*240 resolution and looks terrible when scaled to 800*600 for
> s-video. Has anyone found a USB camera that gives suitable resolution and
> refresh rates which is small enough to be head mounted?
As far as I know the maximum resolution you can get from USB is something
odd like 352x288. This is some sort of standard. If you want to capture at
higher resolution then you should look at different video capture cards,
such as the Hauppauge Impact VCB or Win TV cards or something more
> 4) Finally, the glDrawPixels OpenGL function is extremely slow on the PC
> and infacts seems to conflict with the Hercules graphics card (symptoms
> include - just won't render to screen!). Has anyone had similar experience
> and/or tried any alternatives E.g. rendering the video image to a texture on
> a 2D surface?
glDrawPixels is very slow on a PC. The solution is to use a video texture
map and draw the video image to the screen all at one as one big texture
map.. When we did this with our Asus card performance went up from 3-4
frames/second to 13-15.. I can send you sample code if you like.
I hope this helps..
Mark Billinghurst | Human Interface Technology Laboratory
grof@h .................. | University of Washington, Box 352-142
fax: +1-206-543-5380 | Seattle, WA 98195