Hi there,

i'm working on my diploma thesis by using ARToolKit (ver. 2.72). I wanna
track markers outdoor, 1st tests gone very badly because the longest
distance i passed was only as far as 6 meters (marker size: 64x64cm 800x600
resulution, 15fps). I'm using a Logitech QuickCamR Pro 9000. Anyone here
have got some experiences by passing long distances outdoor? I'd intercalate
the size of the marker, so it must be round about 4,5x 4,5meters (!) for a
range of 30meters between cam and marker?!

balko

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Balte,

One thing that sometimes traps users new to ARToolKit is the  
coordinate system.. by default, if you've used the standard  
calibration pattern, ARToolKit will be calibrated in millimetres.  
This will quite quickly bite you if you're using a big real-world  
coordinate system, because of 1) the OpenGL clipping planes 2) odd  
effects if you try to use glScale.

One way to deal with this is hinted at in the simpleLite example in  
ARToolKit 2.x. You'll need to make changes in two places:
1)	arglCameraFrustumRH(&gARTCparam, VIEW_DISTANCE_MIN,  
VIEW_DISTANCE_MAX, p);
Here you can adjust the near and far clipping planes (they are set to  
the constants VIEW_DISTANCE_MIN and VIEW_DISTANCE_MAX in this example).
2)	arglCameraViewRH(gPatt_trans, m, VIEW_SCALEFACTOR);
Here you can adjust the scalefactor applied to distances measured  
with ARToolKit. E.g. if you calibrated ARToolKit to millimetres (the  
default) but you want 1 drawing unit (i.e. glTranslate(1.0, 0.0,  
0.0)) to be a metre in your virtual space, you would use a value of  
0.001 in place of VIEW_SCALEFACTOR.

The other way is to just calibrate your camera in different units,  
i.e. when running calib_camera2, instead of answering "40" to the  
initial question about dot spacing, answer e.g. 0.04 (to calibrate in  
metres). (N.B. there may be numerical effects on the calibration  
calculations from this change which I haven't thought through.)

Regards,
Phil.

On 10/09/2007, at 9:06 AM, Balte Jorns wrote:

> Hi there,
>
> i'm working on my diploma thesis by using ARToolKit (ver. 2.72). I  
> wanna
> track markers outdoor, 1st tests gone very badly because the longest
> distance i passed was only as far as 6 meters (marker size: 64x64cm  
> 800x600
> resulution, 15fps). I'm using a Logitech QuickCamR Pro 9000. Anyone  
> here
> have got some experiences by passing long distances outdoor? I'd  
> intercalate
> the size of the marker, so it must be round about 4,5x 4,5meters  
> (!) for a
> range of 30meters between cam and marker?!
>
> balko
>
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hi Balte,

can you give more details, what kind of problems you experience?
Do you have problems rendering the scene or does the tracking itself fail?

Daniel



Balte Jorns wrote:
> Hi there,
>
> i'm working on my diploma thesis by using ARToolKit (ver. 2.72). I wanna
> track markers outdoor, 1st tests gone very badly because the longest
> distance i passed was only as far as 6 meters (marker size: 64x64cm 800x600
> resulution, 15fps). I'm using a Logitech QuickCamR Pro 9000. Anyone here
> have got some experiences by passing long distances outdoor? I'd intercalate
> the size of the marker, so it must be round about 4,5x 4,5meters (!) for a
> range of 30meters between cam and marker?!
>
> balko
>
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>   

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