November 15th, 2008

Exercise 8 – Filters

texture-cube.pngMost people are familiar with the concept of filters, in fact unconsciously used them many times. Everytime you sharpen an image or apply a gaussian blur, every single pixel gets processed by a certain mathematical rule.

This post demonstrates a few well known filters and reveals the magic of what goes on under the hood.

Task 1+2: Filter types

There a lot of filter masks. This applet demonstrates a few of them (accessible by the keys 1-5):

  1. High-pass
  2. Low-pass
  3. Laplace
  4. Prewitt
  5. Sobel (horizontal)
This is what the matrices look like for the respective filters:

Task 3: Image Sharpening

This is a practical usage of the filter types shown in task 1 and 2. First, we “clean up” the noise in the original picture and sharpen it. In the applet, you can use the keys 1-7 to apply the different steps BETA.

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