3D
Measurements is still being a great challenge. Although a lot of research is
involved in stereovision systems, most of the geometrical problems can be
minimised when the system is used for industrial applications. Moreover, light
control can be achieved allowing better segmentation results. The Robotics and
Computer Vision Group at the University of Girona is involved in 3D Measurement
developing systems for either research or industrial applications. Coded
structured light is based on the projection of a light pattern that has been
previously coded in order to solve the correspondence problem. Then, this light
pattern is projected onto a scene and the captured by a camera. Linear a
nonlinear calibration are used to model the camera and the pattern projector.
Triangulation is applied to obtain 3D reconstruction of the scene and a single
pattern projection allows the system to measure moving objects. Some
application of this technique has been tested in an underwater robot as we
describe in the next section with the aim of obtaining the desired 3D
information for navigation.
Fig: 1 moving hand imaged by the pattern and its final
reconstruction.
MAIN CONTOUR DETECTION
AND APPLICATIONS:
The work developed in
this vision area by our Group consists initially in the
segmentation of natural scenes based on the obtaining of a set of frontiers of
the most
perceptively significant regions, the so-called Circumscribed Contours.
This method is
based on two main properties: The contour must have an important length and
that the
contours separate sufficiently differentiated regions. The proposed algorithm
for segmentation runs in four phases: 1. - Obtaining of the Integrated
Local Contour Image. 2. - Contour Restoration and Pruning. 3. - Analysis
of Contour Separation Capabilities (chromatic characteristics and texture). 4.
Obtaining of the Most Relevant Contours: Relevance value of each contour. The
final result is an
image with the identification of its main contour.
ROBOTICS
FIELD:
Underwater
Robotics and Vision Applications:
In
collaboration with the Polytechnic University of Catalonia (UPC) our research
group has
developed a low cost underwater robot called Garbi. It is oriented both
to perform undersea
observations and to carry out simple manipulation tasks like sample collection.
The robot is
teleported from a surface computer connected to the underwater unity through an
umbilical
cable. Its two 3 DOF arms can be controlled by using an special developed
exoskeleton
mounted on the operator's chair. In the field of underwater robotics, we are
working on the
mathematical modelling of the vehicle and the definition and implementation of
a hybrid
control architecture to transform the robot in a full autonomous underwater
vehicle. By
means of positioning by laser recognition we are involved in a project of
co-ordinated cooperation for specifically tasks of two teleported underwater
vehicles.
Fig
4. The Garbi Underwater Robot and the laser positioning
system Fig. 5 Garbi carrying out a task.
Lecturer
Mr.
Hojiwala Robin A.
Mahavir
swami polytechnic
Nice
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