Image Fusion Using the Wavelet Analyzer App

The principle of image fusion using wavelets is to merge the wavelet decompositions of the two original images using fusion methods applied to approximations coefficients and details coefficients. For more information, see [MisMOP03] and [Zee98] in References.

The two images must be of the same size and are supposed to be associated with indexed images on a common colormap (see wextend to resize images).

Two examples are examined: the first one merges two different images leading to a new image and the second restores an image from two fuzzy versions of an original image.

Start the Wavelet Analyzer App.
From the MATLAB^® prompt, type waveletAnalyzer to display the Wavelet Analyzer and then click the Image Fusion menu item to display the Image Fusion Tool.
Load the original images: a mask and a bust.
```
load mask; X1 = X;
load bust; X2 = X;
```
In the Image Fusion tool, select File > Load or Import Image 1 > Import from Workspace. When the Import from Workspace dialog box appears, select the X1 variable, which loads the mask image.
Perform the same sequence choosing the X2 variable to load the bust image.
Perform wavelet decompositions.
Using the Wavelet and Level menus located to the upper right, determine the wavelet family, the wavelet type, and the number of levels to be used for the analysis.
For this analysis, select the db2 wavelet at level 5.
Click the Decompose button.
After a pause for computation, the tool displays the two analyses.
Merge two images from their decompositions.
From Select Fusion Method frame, select the item mean for both Approx. and Details. Next, click the Apply button.
The synthesized image and its decomposition (which is equal to the fusion of the two decompositions) appear. The new image produced by fusion clearly exhibits features from the two original ones.
Let us now examine another example illustrating restoration using image fusion.
Restore the image using image fusion.
From the File menu, load Image 1 by selecting the MAT-file cathe_1.mat, and Image 2 by selecting the MAT-file cathe_2.mat.
Using the Wavelet and Level menus, select the sym4 wavelet at level 5. Click the Decompose button.
From Select Fusion Method frame, select the item max for both Approx. and Details. Next, click the Apply button.
The synthesized image is a restored version of good quality of the common underlying original image.