Edge Preserving Smoothing
Nonlinear Gaussian Filter Chains
Prof. Dr. V. Aurich
Institut für Informatik
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Example for Edge Preserving Smoothing of an Image Sequence

The file 3Ddemo.tar.gz is a gtared and gzipped directory named 3Ddemo which contains the 64 images of the sequence in PGM format. They show two moving and blinking squares. The original sequence has been disturbed by additive Gaussian noise the variance of which is so large that in each single image the squares cannot be seen any more. Nevertheless a three-dimensional nonlinear Gaussian filter chain is able to extract them again.

Notice that also human observers detect the squares immediately if the image sequence is displayed with a faster image rate. If you have the ImageMagick package you can animate the sequence using the command: animate 3Ddemo/*
Be patient! ImageMagick needs some time to load all images.

Each image of the sequence consists of 4 subimages:

the undisturbed image the disturbed image
the result of the filter chain the locally binarized result

This is e.g. the 33rd image of the sequence: