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Dr Libor Spacek
Omnidirectional Vision
Image Capture Equipment
Catadioptric sensors use a rotationally symmetrical mirror viewed along its central (rotation) axis by a camera. The catadioptric sensor consisting of a conical mirror and an ordinary perspective camera has the following advantages:
  1. It is simple to set up and operate. The equipment is relatively inexpensive and the cameras are widely available.
  2. The projection is the same regardless of its direction (isotropic).
  3. It captures the entire scene in a single instant, making it well suited to analysis of dynamic environments and/or moving cameras.
  4. The image resolution and distortion of the cone mirror are favourable in comparison with other shapes of catadioptric mirrors.
We are also using true fisheye lenses (field of view of at least 180 degrees wide, i.e. hemispherical), see the front page.

Omnidirectional Sensor Image Registration Isotropic Dynamic Image Resolution Notes
Rotating camera mechanical problems only for the single central column of pixels perpendicular to the rotation no, time delay high when all columns are used no good for dynamic scenes
Regular polyhedrons of mirrors and several cameras complicated no, combinations of mirrors are not circularly symmetrical yes, when cameras are synchronised medium too many cameras
Catadioptric ok, especially with single viewpoint yes yes low easily obstructed, potential mirror support and mirror registration problems
True fisheye easy but the lens needs calibration/correction yes yes very low at the periphery, medium to high in the centre unobstructed hemispherical view

logo img left portrait logo img right portrait Designed and maintained by Dr Libor Spacek. Updated Friday, 23-Mar-2007 13:01:47 GMT
publications,  biography, email: spacl (@essex.ac.uk).
Some of my courses: Computer Vision,  Sensor Signal Processing,  Vision for Robotics,  Robot Programming.