On 31 Okt., 03:14, Tom Sharpless <tksharpl...@gmail.com> wrote:
> It is a fact that SIFT does not find as many matches as we would like > in wide angle and especially fisheye images. But that problem will > not be solved by better matching of affine transformations, as it is > due to image deformations, characteristic of those lenses, that are > not affine transformations. I've thought about the matter and come up with this train of thought: If you look at two corresponding small sections of, e.g., two fisheye images taken with different orientation, the transformation from one to the other is not, but resembles an affine transformation. The smaller the bits you compare, the closer the semblance. So looking at affine transformations helps, since a particular affine transformation locally approximates the actual nonaffine transformation. If the lens geometry is known, though, the choice of which affine transformation of which subsection of the image to feed into a feature generating algorithm could be narrowed down to that affine transformation that best locally approximates the non-affine transformation, thus gaining some efficiency. I admit that this is more of a gut feeling than something I could easily demonstrate mathematically, but maybe someone with a firmer mathematical background could give a comment? with regards Kay -- You received this message because you are subscribed to the Google Groups "Hugin and other free panoramic software" group. A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ To post to this group, send email to hugin-ptx@googlegroups.com To unsubscribe from this group, send email to hugin-ptx+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/hugin-ptx