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Re: stitching of shots from the inside of a sphere

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  • Erik Krause
    ... I don t think this would help. One element of the lens is the eye itself, which you can t calibrate. Furthermore there most likely is non-symmetric
    Message 1 of 5 , Nov 19, 2012
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      Am 19.11.2012 18:07, schrieb Thomas:
      > Specifying that the source projection is spherical might be a good
      > starting point, but the lens that took the pictures has to considered
      > too. If it is rectilinear, then what you have is some rectilinear
      > projections of patches of a sphere, and a rectilinear correction
      > might give a less distorted final picture. Ideally you should
      > calibrate the camera by taking a 360 degree set of pictures of
      > something other than an eye, having plenty of local detail, with a
      > 50% overlap between images.

      I don't think this would help. One element of the "lens" is the eye
      itself, which you can't calibrate. Furthermore there most likely is
      non-symmetric distortion due to the different angles the ophtalmoscope
      (or fundus camera) is placed relative to the lens of the eye. So this
      images are not taken from the middle of the sphere, but from an opening
      in the sphere and with a "lens" where part of the lens elements are
      tilted relative to the others. All this would give a pretty non-uniform
      mapping.

      May be this could be corrected using mosaic mode (in hugin) respectively
      viewpoint correction (in PTGui). I guess a perfect fit would only be
      possible with morphing software.

      However, I would like to try on those images. Thierry, could you provide
      them?

      --
      Erik Krause
      http://www.erik-krause.de
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