Comments on: Augmented Reality with NyARToolkit, OpenCV & OpenGL

By: Roy

Roy — Wed, 25 Nov 2009 20:36:37 +0000

Thank you! Yoel, for your contribution
כן ירבו, תודה

Roy.

By: Yoel

Yoel — Wed, 25 Nov 2009 00:07:07 +0000

Oh forgot one more thing – minor modification on util.cpp
http://paste.cdtag.de/view.php?id=3462

By: Yoel

Yoel — Wed, 25 Nov 2009 00:01:57 +0000

Hi Roy!
Thanks a lot for the tutorial, i found it very usefull =)

For anyone trying to build it with latest NyARToolKit on visual studio 2008 there are some minor changes you need to do.
To save you the trouble you can take a look here:
http://paste.cdtag.de/view.php?id=3460

This is what you should expect:
http://paste.cdtag.de/uploads/2209/marker-4.JPG

(I took the liberty of fixing the lighting a bit and switching to teapot =D)

I had to rebuild NyARToolKit and do the following change:
http://paste.cdtag.de/view.php?id=3461

(Pretty brute, but works…)

Just wanted to save some other people the time it took me to figure this out =)

Thanks again Roy for this tutorial, it was great

By: Roy

Roy — Wed, 09 Sep 2009 06:54:45 +0000

Hi Romano

Yes, I did the calibrations with the tools from ARToolkit.
I heard these calibration tools are outdated and there are better tools to do it (I know OpenCV has calib. tools), but there are compatibility issues with ARToolkit.

Roy.

By: Romano

Romano — Tue, 08 Sep 2009 17:17:08 +0000

Hello,

how do you calibrate the camera? Using ARToolkit?

Thanks,
Romano

By: Jimmy

Jimmy — Thu, 13 Aug 2009 17:21:50 +0000

Hi Roy,

I just started figuring out how to use NyARToolkit (C++ version). I’m still in the stage of setting everything up but your tutorial has been incredibly helpful so far.

I’m not sure if I have a later version or not, but a quick thing: the NyARSingleDetectMarker() function needed a fourth parameter. Something like this should work although I’m not sure if it’s correct since I’m still finding my way around:

ar = new NyARSingleDetectMarker(&ap,code, 80.0,ra->getBufferReader().getBufferType());

As of right now ar->detectMarkerLite(*ra, 100) is always returning true, so I must be doing something else wrong somewhere.

Jimmy

By: Roy

Roy — Fri, 07 Aug 2009 19:07:40 +0000

Hi Fugitive
I just used the function
void arglCameraFrustumRH(const NyARParam& cparam, const double focalmin, const double focalmax, GLdouble m_projection[16])
with these parameters:
arglCameraFrustumRH(ap,1.0,100.0,camera_proj);

Take a look in the void init ( GLvoid ) function in main.cpp.

This creates a projection matrix for OpenGL, with z-near = 1.0 and z-far = 1000.0 (plenty 3D space to draw in). The projection is based on the calibration inside the NyARParam (loaded from file) which I did earlier using the calib tools from ARToolkit.

Good Luck
Roy.

By: Fugitive

Fugitive — Thu, 06 Aug 2009 02:44:39 +0000

Hi,

Nice tutorial!

I noticed you glossed over the line:
glLoadMatrixd(camera_proj);

without explaining how you managed to get the real-world camera projection matrix to conform to opengl.

I know that using the opencv projection matrix (http://opencv.willowgarage.com/documentation/camera_calibration_and_3d_reconstruction.html) directly doesn’t work. Would you be so kind as to explain a bit?

Full reference of question:
http://www.opengl.org/discussion_boards/ubbthreads.php?ubb=showflat&topic=50767&gonew=1