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5.2.1 Design of an AR-based sensor fusion visualization
The first step of the development of the MOSTAR interface has been
the definition of a method to convert laser data to a set of graphical
objects to be overlaid onto camera images.
Colored 3D virtual objects have been chosen to represent laser data
on the image. Virtual objects are positioned within the virtual 3D
workspace according to laser measures, and they are rendered as a semi-
transparent overlay above the camera image. It has been necessary to
select appropriate 3D objects to represent laser data, and colors which
were suitable to map distance in an intuitive way (section 6.1).
As it has been shown in section 3, determining which visualization
method is the most effective for complex data like those provided by a
mobile robot is not a straight-forward issue. It is necessary to take into
account numerous factors, among which the specific context of applica-
tion and the user particular preferences. For example, a 2D bird’s eye
view map of the robot workspace can be a very effective visualization
method for the exploration of an environment, but it would usually not
be sufficient for obstacle avoidance manoeuvres. Therefore, several rep-
resentation modes have been designed for the MOSTAR interface, and
several brief tests have been performed in order to determine points of
strength and weaknesses of each mode.
Furthermore, an algorithm to refine the graphical appearance of the
overlay by detecting potential laser outliers has been developed (section
6.2).
5.2.2 Definition of a laser-camera model and a calibration
procedure
A calibration procedure is clearly needed in order to correctly align
virtual objects defined in section 6 with the real objects in the camera
images.
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