This software uses the projective transformation to register images of a rather flat scene obtained from
different views. The registration is fully automatic and the user only provides the names of the two images to
be registered. The program will then register the images and display the result. The registration process
involves selecting a set of landmarks in each image, determining the correspondence between them,
calculating the transformation parameters from the correspondences, and using the transformation to register
the images.

Assumptions: It is assumed that
  • the imaged scene is rather flat,
  • 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 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 using a larger number of landmarks. 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 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 images of a relatively flat art piece from slightly different views. (c) Registration using the
default mode. (d) Refinement of the registration.
(a)
(b)
(c)
(d)
Fig. 2. (a), (b) Two aerial images taken from slightly different views of a relatively flat scene. (c) Initial
registration. (d) Refined registration. The refinement step, although taking only a few seconds, can
significantly improve registration result.
(a)
(b)
(c)
Fig. 3. (a), (b) Two images of a flower garden. (c) Automatic registration of the images by the projective
transformation. Although the scene is not completely flat, compared to the distance of the camera to the scene,
changes in scene elevation are small. The images have been obtained from slightly different views.
To obtain a license for this registration software, please follow the link=>
2-D auto projective registration
Image Registration and Fusion Systems