Image fusion is the process of combining information of interest in two or more images of a scene into a single highly
informative image. Information of interest depends on the application under consideration.

An example of image fusion to maximize information content
in an image is given below.  Images (a) - (f) in FIg. 1
represent bands 1, 2, 3, 4, 5, and 7 of a Landsat TM image
, and image (g) shows fusion of these bands.
(a)
(b)
(d)
(c)
(e)
(f)
(g)
Fig. 1. (a)-(f) Bands 1, 2, 3, 4, 5, and 7 of a Landsat TM image. These images are courtesy of NASA. (g) Details in
all images are fused into a
single image.
Image fusion techniques assume that the provided images are already registered. In many situations, this assumption
does not hold and the images need to be registered before fusing them. In the following, an example of multi-exposure

and multi-focus
image fusion is given where the images are not registered. First, the  images are registered and then
fused.
An example is given below. To see further examples of image registration followed by image fusion, visit the
Combined Image Registration and Fusion page.
(a)                                                                                          (b)
(c)                                                                                          (d)
Fig. 2. (a) - (4) Four images obtained by a hand-held camera at different exposure and focus levels. (f) The fused
image. First, images (b) - (
d) are registered to image (a). Then, the registered images are fused to create image (e).
(e)
Image Fusion
Image Fusion Systems Research