An “On-the-Fly” Pseudo Model-based Augmented Reality



			An “On-the-Fly” Pseudo Model-based Augmented Reality

			There have been very widespread applications of augmented reality, such as in education, entertainment and simulation etc. Most tabletop augmented reality applications use fiducial markers for tracking, and rely on accurate tracking and mapping of database of marker images. The problem with this marker-based approach is that loss of tracking is unavoidably frequent, due to partially occluded marker, poor ambient lighting. Marker-based tracking is also undesirable due to the unaesthetic fiducial marker.



			In advanced augmented reality the trend is to make use of useful feature on the subject for tracking purposes. Feature-based tracking tracks 2D and 3D surfaces. Normally in this approach the 2D or 3D models of objects or scenes need to be created beforehand – this is a time-consuming process. We develop an “On-the-Fly” approach which allows developers to create models “on-the-fly” easily and quickly. It basically uses a pointing device which we call the 3D digitizer. It has an infra-red LED at the tip.



			Overall setup and idea Two Wii Remote cameras are mounted on the wall/ceiling. The cameras are able to track the 3D digitizer. Another viewing camera is attached to user’s head-mounted display. The user uses the 3D digitizer to point at surfaces of the object of interest, in order to map out the useful features on the object. The Wii Remotes can track the 3D digitizer at very high rate. The 3D position of the digitizer can be found by triangulation. After this, the tracking algorithm kicks in and tracks these natural features.



			The tracking techniques is a combination of scale-invariant feature transform (SIFT) and parallel tracking and mapping (PTAM).

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