Hi Daniel,

I am now using the multimarker tracker in ARToolKitPlus (2.0.1) on
linux. I know how to find the (relative) matrices of the markers defined
in the multimarker cfg but I can't find the functions to get the
matrices of the markers which are not in the multimarker cfg file.

Could you tell me how I can get these matrices?

Thanks a lot.

Best regards
Raymond


-- 

 Raymond de Vries, VR Specialist
  Insight Services
  SARA Computing and Networking Services, PO Box 94613, 1090 GP  AMSTERDAM
  email: raymond at sara.nl   Phone +31-20-5923000  Fax +31-20-6683167

Daniel,

>>I am now using the multimarker tracker in ARToolKitPlus (2.0.1) on
>>linux. I know how to find the (relative) matrices of the markers defined
>>in the multimarker cfg but I can't find the functions to get the
>>matrices of the markers which are not in the multimarker cfg file.
>> 
>>
>>    
>>
>i'm not sure if i understand your question...
>  
>
I will try to explain my problem in another way.

Let's say I have a multimarker cfg file:
2
483
40.0
0.0 0.0
 1.0000  0.0000 0.0000 0.0
 0.0000  1.0000 0.0000   0.0
 0.0000  0.0000 1.0000    0.0
482
40.0
0.0 0.0
 1.0000  0.0000 0.0000  -60.0
 0.0000  1.0000 0.0000   60.0
 0.0000  0.0000 1.0000    0.0

Now, I would like to track other markers as well, for instance marker
with id 428. When all 3 markers are in the viewport, the multimarker
tracker detects them all (for instance "const
ARToolKitPlus::ARMarkerInfo &detectedMarker =
tracker->getDetectedMarker(detectedMarkerCounter);").

Now, in order to render virtual objects at the markers 482 and 483 I get
the transform with "tracker->getModelViewMatrix()" and
"artkpConfig->marker[multiMarkerCounter].trans" (with conversion to
OpenGL coordinate system).

I would also like to render at marker 428 but I don't know how to get
the modelview matrix for this marker.

>if you want to mix single and multi-marker tracking than you can not use
>the high-level classes TrackerSingleMarker and TrackerMultiMarker but
>instead you'll have to work with the base class called Tracker which
>exposes the full functionality of ARToolKit(Plus).
>  
>
I will take a look there.

thanks
Raymond

>Daniel
>
>  
>


-- 

 Raymond de Vries, VR Specialist
  Insight Services
  SARA Computing and Networking Services, PO Box 94613, 1090 GP  AMSTERDAM
  email: raymond at sara.nl   Phone +31-20-5923000  Fax +31-20-6683167

Raymond de Vries wrote:

>I am now using the multimarker tracker in ARToolKitPlus (2.0.1) on
>linux. I know how to find the (relative) matrices of the markers defined
>in the multimarker cfg but I can't find the functions to get the
>matrices of the markers which are not in the multimarker cfg file.
>  
>
i'm not sure if i understand your question...

if you want to mix single and multi-marker tracking than you can not use
the high-level classes TrackerSingleMarker and TrackerMultiMarker but
instead you'll have to work with the base class called Tracker which
exposes the full functionality of ARToolKit(Plus).

Daniel

hi Raymond,

as i already mentioned, in order to use single- and multi-marker at once
you'll have to use the more complex low-level Tracker API instead of the
simple high-level classes. i implemented this for the ARToolKitPlus
module in OpenTracker some time ago, so i know that it works...

here is basically what you have to do:


first call arDetectMarker() to let ARToolKitPlus find all markers in the
image. this does not do any pose detection yet. like this:

tracker->arDetectMarker((ARToolKitPlus::ARUint8*)frameData,
tracker->getThreshold(), &markerInfo, &markerNum );

then you have to check all found markers (markerInfo) on your own and
call arGetTransMat() for all marker that are known to be "single-marker"
like this:

// assumes that marker j is a "single-marker"
// returns the transformation matrix in 'matrix' (last parameter)
tracker->arGetTransMat(&markerInfo[j], source_center, source_size, matrix);

then you check if any multi-marker id was found. if so, get the
multi-marker-config that contains that marker and pass it onto
arMultiGetTransMat(): like this:

// returns the transformation matrix in mmConfig->trans
tracker->arMultiGetTransMat(markerInfo, markerNum, mmConfig);


that should do the trick...

bye,
Daniel