Scarica (PDF – 6.19 MB)

4.5 Summary and analysis
In [59] and [60] two different approaches to visualization interfaces for
mobile robot teleoperation are described. The visual-based approach
consists in displaying a (mono or stereo) video stream from the remote
site, while the laser-based approach consists in displaying a synthetic
view of the robot workspace generated from laser range data.
Each approach has its points of strength and weaknesses. Visual
data is highly contrasted, and provides a high amount of information
and a wide field of view to the operator, but the massive quantity of
data to be transmitted implicates a delay between the visualization of
consecutive frames if the available bandwidth is low. Laser-generated
images are much poorer in detail than video, but they can be generated
and visualized in real-time.
The works exposed above show that both visualization methods
greatly benefit from stereoscopic visualization. Stereo increases the
sense of presence of the operator in the remote environment and the
perceived sense of depth, thus increasing driving accuracy.
Livatino et al. [13] introduce an innovative methodology to join the
advantages of these two approaches by using augmented reality. Col-
ored overlays are used to fuse visual and laser data in a unique, coherent
and intuitive representation. Though, application of stereoscopic visu-
alization to this methodology has proven not to be straight-forward. In
fact, a technique has to be developed to conciliate the results of left and
right image processing in order to obtain a correct stereo rendering.
43