Dr. Benjamin Tordoff

Queen Mary Vision Laboratory seminar

Date: Monday 9th June
Time: 2pm

Dr. Benjamin Tordoff

Active Vision Laboratory
Robotics Research Group
University of Oxford

Active Control of Zoom

The first part of this talk looks briefly at some of the optical
properties of zoom lenses which have been shown to be important for
computer vision applications. In particular the effect that lens
distortion can have on structure from motion algorithms is described,
focussing on the case of little or no camera translation.

Moving on to the mechanical aspects of zoom lenses, for real-time
control of a lens the performance and response of the lens must be
categorised and calibrated. This is done in the context of Firewire
cameras mounted on the Yorick 8-11 active vision platform, allowing the
complete calibration of the visuo-control loop.

In the final two parts of the talk, two algorithms are introduced which
actively control zoom to enhance tracking in some way. In the first,
zoom is controlled in such a way that resolution is maximised whilst
maintaining a low probability of target-loss. The second algorithm is
higher-level, using scene-based measures to control zoom for maximum
image stability.