Hi,
Check out a paper I presented at the ART workshop a few years ago:
http://www.tinmith.net/papers/piekarski-art-2002.pdf
It talks about how we straightened out errors in the camera_para.dat =20
file for use in a hand tracking application, these errors are =20
accumulated during the camera calibration process. Normally ARToolkit =20=
doesn't have a problem with whatever the calibration is but if you =20
are trying to use it as a tracking device then you need to make sure =20
the camera axes are orthogonal.
regards,
Wayne
------------------------------------------------------------------------=20=
---
Dr Wayne Piekarski - Researcher / Lecturer pho: =20
+61-8-8302-5070
fax: =20
+61-8-8302-3381
Assistant Director - Wearable Computer Lab mob: =20
+61-407-395-889
School of Computer and Information Science ema: =20
wayne@c ..............
University of South Australia www: http://=20
www.tinmith.net
On 09/03/2006, at 2:21 AM, Antonio Bleile wrote:
> Hi,
>
> how would I create a camera_para.dat that
> models an ideal perspective camera like
> an OpenGL perspective Camera?
>
> Suppose I set-up a camera with gluPerspective:
>
> gluPerspective( fovy =3D 60.0 /*degrees*/,
> GLdouble aspect =3D 1.3,
> GLdouble zNear =3D 1.0 ,
> GLdouble zFar =3D 1000.0 )
>
>
>
> I tried to set the artoolkit param structure like this:
>
> ARParamDouble param;
>
> // first column
> param.mat[0][0] =3D 2*640/(640.0/480.0);
> param.mat[1][0] =3D 0.0;
> param.mat[2][0] =3D 0.0;
>
> // second column
> param.mat[0][1] =3D 0.0;
> param.mat[1][1] =3D 2*480;
> param.mat[2][1] =3D 0.0;
>
> // third column
> param.mat[0][2] =3D 640.0/2.0;
> param.mat[1][2] =3D 480.0/2.0;
> param.mat[2][2] =3D 1.0;
>
> // fourth column
> param.mat[0][3] =3D 0.0;
> param.mat[1][3] =3D 0.0;
> param.mat[2][3] =3D 0.0;
>
> param.xsize =3D 640;
> param.ysize =3D 480;
>
> param.dist_factor[0] =3D 640.0/2.0;
> param.dist_factor[1] =3D 480.0/2.0;
> param.dist_factor[2] =3D 46.0; /* 60.0/1.3 (??) */
> param.dist_factor[3] =3D 1.00;
>
>
> I then render with the opengl camera a
> plane with a marker-texture. The output is
> read by ArToolKit(Plus). It seems correct
> when the marker is more or less in the center
> of the scene but the perspective gets somehow
> screwed when I move the marker towards the
> edges. Any ideas?
>
> Cheers,
>
> Toni
>
>
> --
> Ing. Antonio Bleile
> Seac02 S.r.l.
> via Avogadro 4
> 10121 Torino Italia
> Tel. +39.011.197.006.52
> Fax +39.011.197.006.53
> E-mail antonio.bleile@s ........
> Sito www.seac02.it
>
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