RESEARCH OF REGISTRATION METHOD IN VIDEO-BASED
AUGMENTED REALITY
Xueling Wu 1,
2 , Qingyun
Du2, Fu Ren 2
1.
2.
Augmented
reality (AR) is a technology of merging additional information generated from a
computer model into a user’s view to enhance or augment perception of a real
environment. And geographical information system (GIS) plays an important role
in management and processing of spatial data which describes plane position and
basis outline of spatial object. As for true representation of the real world,
it is not enough. Therefore, the paper introduces AR into GIS to promote the
development of outdoor AR system, and also would explore a new research
direction for geographical information science. One of the key tasks for
augmented reality in GIS is to make the virtual and real scene merged correctly
to support user’s operation and decision.
Firstly, in
most of augmented reality systems the real object is static, such as wall and
architectures. While the researches pay no attention to dynamic object
tracking. In order to solve this problem, the paper analyzes and compares two
existing registration methods: registration of augmented reality based on a few markers points with
different colors and natural characteristics to find the essential difference between
those two methods. In the former, the position and orientation of
identification points and video of template are given. So the transition matrix
between the identification template and the image plane can be gotten. While in
the latter, spatial information is introduced.
Secondly it
proposes a new registration method which not only uses idea of identification
point registration, but improves it to realize registration in outdoor video
augmented reality, which uses a see-through head mounted display (HMD) showing
the result of registration, and a single color CCD camera capturing video. Furthermore,
the paper utilizes 3D compass and GPS
attached on user’s body to calculate transition matrix from world coordinate
system to camera coordinate system, which 3D compass provides rotation
parameter through three angles including pitch, heading and roll. Simultaneously,
the translational parameter is supplied by GPS receiver. And the transition relation
from virtual coordinate system to world coordinate system is given.
Lastly,
transition matrix from virtual coordinate system to the image plane can be
calculated. Only by this, 3D virtual object generated by computer model is
added into the HMD as a whole. Synthetically, video-based registration
offers a superior approach to 3D registration of dynamic object. The new method
significantly simplifies the registration system and coordination errors are
eliminated. The method requires little computation and can be easily realized
in real time. In the end, the paper discusses the further related research
works, and the important significance of its development.