This image finder uses the same algorithm as the border finder, but rather than
using the rectangle in the projection plane, we assume that only a subrectangle
which of the image (which may be rotated with respect to the image) is valid.
A limits file is associated with each input image and contains a specification of the
bounding rectangle in terms of the pixels of the original image.
Fields inherited from class skyview.process.imagefinder.RectRecurse