Why fisheye lens?
- It captures a wide field of view (FOV). For example, the Nikon FC-E8 lens has FOV 183 degrees.
- It can be used instead of mirrors to produce omnidirectional images.
- It can be easily focused.
- The resulting omnidirectional sensor is more compact and easier to assemble than the setup with mirrors.
FC-E8 lens requires different model than pinhole cameras, due to a large
field of view, a spherical retina has to be used. The projection model we use
descibes relation between the angle theta, between the optical axis and the light
ray, and distance r from the image center in the image. Our projection model
assumes radial symmetry and a single center of projection.
The model for the Nikon FC-E8 fish eye lens was determined empiricaly by fitting
several functions, including polynomials of various degrees, to data. The
following function with four parametes (a, b, c, d) povided the best fit:
References
Panoramic Mosaicing with a 180 Field of View Lens. Hynek Bakstein and Tomas Pajdla. In Proceedings of the IEEE Workshop on Omnidirectional Workshop, pp. 60-67, IEEE press, June 2002.
[pdf]
Presentation given at the Omnivis workshop [pdf] and a video.
