Therefore, it is
desirable if the global motion model we need to recover is translation, which
has only two parameters. It turns out that for a pure panning motion, if we
convert two images to their cylindrical maps with known focal length, the
relationship between them can be represented by a translation.
Here is an
example of how cylindrical maps are constructed with differently with f’s.
Note how straight lines are curved.
Similarly, we
can map an image to its longitude/latitude spherical coordinates as well if f
is given.
