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Conclusion and future work

The test with the magnetic field indicates, that the useful range of the magnetic field is limited to about 0.5 m. By simply using the application Starwars, this can be verified. If the position and orientation isn't accurate enough anymore , the robot disappears before the door ends, or walks into the wall. Displacement of the saber can also be seen easily. But that's not only the static error of the tracking system. The system delay can be seen when moving the pen left and right in a rather high frequency. The frequency can be chosen such, that if the pen goes right, the saber goes left, and the same the other way round.

Another problem even noticeable in Starwars is the limited field of view. When holding the saber upright, the user can't see both ends of it. The head has to be moved. But many users try to look down, left or right instead of moving the head. Building a mask is a possibly a solution. Because the user can't see the bright environment, and is forced to look through the darker glasses.

Following the jumping ball is a hard task because of the limited field of view, and the system latency. It seems that at least low cost Augmented Reality setups are not well suited for applications with fast movements at the moment.

Possible solutions for the problem with the high system latency could be a hardware upgrade. This is already partly done for the tracking server. And it shows that the dynamic error has decreased dramatically. A prediction unit[2] anticipating user's movements would bring further improvements. The other components as network interfaces and rendering engine should work fast enough for such small applications.

The static error could be reduced with correction curves. Many points with correction data would be needed. Those datas must be tracked very precise, probably mechanically tracked. To correct a volume of \( 2\times 2\times 1 \) meters with a resolution of 10 cm and 10 \ensuremath{}, 4851 points would be needed. Each point needs \( 36^{3}+3=46.659 \) measurements. This would result in more than \( 10^{8} \) measurements.

One further problem is detection of the real world. The Starwars application for example does not recognize when the door is shut, and R2D2 is still drawn. Optical systems could detect changes in the environment, but this task seems to be to complex at the moment.

The future work on AR in general, will focus on develop simpler hybrid tracking systems, combining AR with wearable computers and research on powerful GUI-systems.


next up previous
Next: Bibliography Up: paper Previous: Experiments
vogel 2001-03-19