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Binding vision to
physics based simulation: The case study of a
bouncing ball |
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Brief description A dynamic scene
and, therefore, its visual observations are invariably determined by the laws
of physics. We demonstrate an illustrative case where physical explanation,
as a vision prior, is not a commodity but a necessity. By considering the
problem of ball motion estimation we show how physics-based simulation in
conjunction with visual processes can lead to the reduction of the visual
input required to infer physical attributes of the observed world. Even
further, we show that the proposed methodology manages to reveal certain
physical attributes that are impossible to extract by other means. A series
of synthetic experiments as well as experiments with image sequences of an
actual ball support the validity of the proposed approach. The use of generic
tools and the top-down nature of the proposed approach make it general enough
to be a likely candidate for handling even more complex problems in larger
contexts. Sample results Single view estimation of 3D trajectories
Estimation
of the 3D trajectory of a ball from single camera 2D observations and the
assumption of a given physical world. Seeing through walls with a single camera
Single
view estimation of the 3D trajectory of a ball from partial 2D observations and the assumption of a given physical
world. Left: the actual view showing 2D observations and back-projections of
the estimated and the ground truth 3D ball trajectories, Right: 3D plot of estimated and ground truth 3D
trajectory. Inferring angular velocity
A
ball is thrown with a high back-spin towards a table. By incorporating
physics based simulation, we infer the ball’s 3D trajectory and its linear
and angular velocities from a single camera (camera 7). The proposed method
identifies that a back-spin is the cause of the reduction of the outgoing
angle of the bounce. The green ellipses are projections of an equator of the
ball and the arrows represent the direction of the estimated angular speed. Contributors Nikolaos
Kyriazis, Iasonas Oikonomidis, Antonis
Argyros. This
work was partially supported by the IST-FP7-IP-215821 project GRASP. Relevant publications ·
N. Kyriazis I. Oikonomidis, and
A.A. Argyros, “Binding vision to physics based simulation: The case study of
a bouncing ball”, in
Proceedings of the 22nd British Machine Vision Conference, BMVC’2011,
University of Dundee, UK, Aug. 29-Sep. 1, 2011. The
electronic versions of the above publications can be downloaded from my publications page. |
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Last update: |
27 August 2011, Antonis Argyros, argyros@ics.forth.gr |
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