Steven,

In my experience, there are two things we can do to make ARToolkit tracking improve, but I have not had the time to test them.

First is to use arGetTransMatCont(...) which reduces jitter by using previous frame estimates in the optimization process (see examples/simpleTest2.c). The second is to edit 'config.h' and increase the pattern normalization size parameters #defined as AR_PATT_SIZE_X and AR_PATT_SIZE_Y (and recompiling). This might come at the cost of slowing things down, but that's the trade-off. I suggest using a filter on top of the per-frame readings to smooth it out.

@misc{kato2009inside,
title={{Inside ARToolKit}},
author={Kato, H.},
year={2009},
month={03}-19}. http://www.hifl.washington.edu/artoolkit/documentation}
}

As far as the magnitude of the jitter, I found a reference that might be useful:

@conference{malbezin2002measuring,
title={{Measuring ARTootKit accuracy in long distance tracking experiments}},
author={Malbezin, P. and Piekarski, W. and Thomas, B.H.},
booktitle={Augmented Reality Toolkit, The First IEEE International Workshop},
pages={2},
isbn={0780376803},
year={2002},
organization={IEEE}
}

Best,
Nikhil

----
Nikhil Karnad
Department of Computer Science and Engineering
University of Minnesota, Twin-Cities
http://www-users.cs.umn.edu/~karnad/

----
On Mon, Nov 8, 2010 at 7:53 AM, Steven Bellens <steven.bellens@mech.kuleuven.be> wrote:
2010/11/8 Steven Bellens <steven.bellens@mech.kuleuven.be>:
> Hi,
>
> I'm experimenting a bit with the ar_pose package. I'm using a single
> fixed camera to track a moving marker. To verify the estimation
> accuracy, I just leave the marker fixed and I've plotted position and
> orientation estimates. The position estimates are pretty much
> constant, but the orientation estimates are oscilating a lot (see
> appendix), and apparently always between two values. Is this because
> of the bad capability to estimate that orientation or can this be
> caused by the environment conditions (light - set-up - distance to
> marker)?

For clarity, plotted are the 4 components of a unit quaternion.

>
> regards,
>
> Steven
>
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