Episode 077: Convoluting the Matrix

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Today we are going into Math-Land, but not too deep – I promise. But first there is a visit to the Oakland Technology Exchange West – a non profit that gives new life to (not so) old hardware.

The Convolution Matrix lives in Math-Land. It is the backbone of a lot of filter plugins. It’s fun to play with if you have understood the basics and lost your fear. One example of a filter done with this is the Pencil Shade Filter by Alex Turner

I forgot to talk about the “Border” options. “Extend” just adds a virtual black border around the source image. “Wrap” takes the pixels from the opposite corner and wraps them around.

The matrix in the image has no deeper meaning, it’s just some random numbers. ;-)

My lens replacement surgery went well and I am recovering fast. Thanks for all the good wishes!


00:19 Welcome
00:23 Oakland Technology Exchange West
02:25 Rolf’s Eyes
03:13 Convolution Matrix Filter
05:18 – User interface
06:08 – Experimenting
06:56 – The documentation
12:30 – sharpening
16:48 – blur
17:16 – normalize option
18:02 – edge enhance
21:38 The End
TOC made by paynekj

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11 thoughts on “Episode 077: Convoluting the Matrix

  1. Hello Rolf,

    Good to hear that your recovery from the eye surgery is going well!

    I just wanted to thank you for mentioning our organization, Oakland Technology Exchange West, in this week’s episode. If anyone in your audience is interested in donating a computer, a good directory can be found at http://www.techsoup.org/servicedirectory/index.cfm . This is mainly for the US and Canada. Of course, anyone in the San Francisco/Oakland area knows where to go now ;)

  2. Convolution matrix filter is as interesting as it is irritating for one simple reason: huge possibilities and the absence of any reasonable way of saving the settings for future use (unless you take a pencil and put all the numbers manually down).

  3. Part of the FX Foundry script package is a huge convolution presets script; worked fine with 2.4, but doesn’t work with 2.6 :-(

  4. Thanks for bringing this up — I’ve had a look at it in Photoshop long ago, but I’ll absolutely have to experiment with it in the GIMP now.

    Best wishes
    / Mats

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Anything to add from your side of the computer?