Hi,

I'm trying to get the ARToolkit DirectShow (2.52) version running under
Windows 2000 and I think there is something wrong with the
ARFrameGrabber class. 

When I run any of the examples they all seem to grab an initial image
(which is actually flipped horizontally) and then the program seems to
freeze as the video isn't updated. In fact, I think that the application
runs fine as it seems to do the mainloop ok and if you start the program
with the camera pointing at a marker it draws the square over it. I
think that the ARFrameGrabber class grabFrame must be doing something
wrong as it doesn't get the new frame from the camera.

I've been trying to recompile everything but this has been fairly
troublesome as I'm new to Visual C++. I guess I'll keep trying to do
this. Is there any good documentation for the ARToolkit under Windows
besides the stuff on the Download page?

By the way, does anyone know if a VRML DirectShow version of the
ARToolkit is going to be released soon?

Thanks

Patrick Sinclair

I have not seen anything like you describe, I have no problems with 
ARFrameGrabber in obtaining continuous images.
But as you say, getting into COM objects and directshow is a headache, 
definately more complex than VFW.

One problem I had is that I that I was unable to change camera 
resolution using ARFrameGrabber, I usually use 640x480, and the 'pin' 
dialog box would not allow me to change from the 'default' of 320x240. 
Has anyone else had this problem, or is it specific to my camera (ibot 
firewire webcam)?

In any event I have rewritten ARFrameGrabber such that you can change 
the pin settings using parameters (instead of having the potential 
difficulty of dealing with a dialog each time you launch, which can be 
difficult in an AR environment!). I have found that the problem is in 
the specification of 32 bit RGB for capture (used in ARFrameGrabber), 
where only 320x240 will work (again, could be specific to my camera). 
Changing the setting to 24 bit RGB frees the limitation, and you can 
capture at 640x480. This means that you have to convert this 24 bit 
image to 32 bit before handing it over to the ARToolkit for pattern 
detection.

If anyone is interested I will email this code to the list in the near 
future, after I have ironed out a few bugs. That is, if anyone else gets 
the same problem, maybe I am just coding my way around a hardware bug!



-- 
______________________________________________________________________
Jeremy Goslin
Geneva Interaction Lab, Université de Genève.
http://www.jeremygoslin.com

I just see that what I spent all day coding was already implemented in 
Gerhard's new version of the code, sorry for wasting everybodies time 
(most especially my own!). Thanks Gerhard!

Alas, I could have been saved dirtying my hands with directx if I had 
kept up with current events!

I would still be interested to know of anyone who cannot change 
resolution using 32 bit, instead of 24 bit, capture though.

-- 
______________________________________________________________________
Jeremy Goslin
Geneva Interaction Lab, Université de Genève.
http://www.jeremygoslin.com