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What bilateral filter can do? Print
Written by Sompon Virojanadara   
Wednesday, 26 March 2008 09:16

        In short, bilateral filter is a edge-preserving smooth filter.  In alittle bit more human language, this filter will remove the noise from video or picture by blur it out but not blur the entire picture, overall shape and features are preserved. To make thing clearer, let's start with this example. To save the server brandwidth, I will demonstrate with this picture instread the video that my filter intended to.

My cat, cute isn't it? 
Figure1: This is an original picture.

        What oftenly happen on the internet is the video got heavily compressed. And this is what happen when the picture got heavily compressed.

 Compressed cat >.<
Figure2: What happen when picture got heavily compressed (100kbps divx codec).

        As you can see, alot of annoying blocky effect happen. The bilateral filter is one of the way to eliminate this blocky effect from the video. Let's pass this picture to bilateral filter.

Restored cat.
Figure3: After pass compressed picture to bilateral filter for the first time

        As you can see, most of the blocky effect disappeared. Now, let's be little greedy. Let's pass the result picture to the bilateral filter again.

My cat painting
Figure4: 2nd pass to the bilateral filter.

        All the blocky effect are gone with some of image detail. However, this may be use for non-photorealistic effect. The rest is up to your imagination.
 

Last Updated ( Thursday, 27 March 2008 10:46 )