This is a program to transform an image by an homography.  The running time is
proportional to the size of the output image.  The basic usage is to extract a
small crop from a huge image, and apply a small homography to the crop.  The
running time is independent of the size of the large image.

This program is used inside the s2p satellite stereo pipeline
http://github.com/cmla/s2p

Right now the input image extraction is performed by gdal, but this dependency
can be easily removed if needed, to use regular libtiff.

HISTORY OF THIS CODE:

Pascal Monasse: original algorithm for correct homographic resampling
Gabriele Facciolo: improvements upon the original algorithm
Marc Lebrun: optimized re-implementation of the C code using SIMD instructions
Carlo de Franchis: interfaces to s2p
Enric Meinhardt-Llopis: put this code in an individual github repository

For a full git history and blame, look at the s2p commit history before the
"c/homography" folder was removed from the tree.