December 14th, 2008 by Rolf
This is just a short show to catch up on my missed show on Tuesday. I’ll look a tiny bit behind the math in the convolution matrix with a spreadsheet model of a single row of pixels.
And I’ll show you an often overlooked feature of GIMP – the screenshot. It’s way more flexible than just pressing “PrntScrn”. It even stores the mouse pointer on a different layer.
The companion file contains also the images for the next show. I was too lazy to un- and repack that again. 
The TOC
00:19 Welcome
00:33 Greetings to Norman
01:10 Understanding the Convolution Matrix
03:48 – Sharpening
05:18 – Blurring
06:43 The Forum
08:16 Screen shots using Gimp
13:03 the End
TOC made by paynekj
This work is licensed under a
Creative Commons Attribution-Share Alike 2.0 Germany License.
Tags: convolution matrix, Printscreen
Posted in Gimp, Gimp video tutorial | 8 Comments »
December 2nd, 2008 by Rolf
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!
The TOC
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
This work is licensed under a
Creative Commons Attribution-Share Alike 2.0 Germany License.
Tags: convolution matrix
Posted in Gimp, Gimp video tutorial | 9 Comments »
Loading ...
