This software uses the affine transformation to register two images. Consecutive frames in a video captured
by a distant camera of a rather flat scene can be registered by the affine transformation. The registration
software is automatic. The user provides the two images to be registered. The program will register the
images and display the result.

 Assumptions: It is assumed that
  • parallel lines in the scene remain parallel in the images
  • the images are in the same modality,
  • at least 50% overlap exists between the images.

If one or more of these assumptions are violated, the program may register the images only approximately, or
report a failure.

 Modes of operation: The program operates at three different modes.
  • Default mode: This is a fast initial mode used to register the images quickly. For some images, this is
     sufficient.
  • Redo mode: For images with considerable intensity differences, it may be necessary to redo the
     registration. The user presses a Redo button after viewing the registration result of the default mode.
  • Refinement mode: In this mode, the positions of the landmarks used in registration are more accurately
    determined by template matching and the registration is repeated. Examples of image registration by
     this software are given below.
(a)
(b)
(c)
(d)
Fig. 1. (a), (b) Two aerial images taken from slightly different views. These images are courtesy of the U.S.
Geological Survey. (c) Registration using the default mode. This takes about 5 seconds. (d) Refinement of the
registration. Affine transformation is an approximation to the projective transformation, an approximation that
may contain large errors when view-angle difference between the images is large. Affine registration is suitable
for registration of satellite images as demonstrated below.
(a)                                                                                      (b)
(c)                                                                                      (d)
Fig. 2. (a), (b) Two Landsat images with small view-angle differences. These images are courtesy of NASA. (c)
Initial registration. (d) Refined registration by this software.
To obtain a license for this registration software, follow this link =>
Automatic affine registration
Image Registration and Fusion Systems