Archive for October, 2008

Exercise 6 – Pixel editing

Thursday, October 30th, 2008

According to Wikipedia, “Image editing” encompasses the processes of altering images, whether they be digital photographs, traditional analog photographs, or illustrations. In our case we alter digital photos and those consist of pixels. Learn more about how to manipulate pixels and techniques to overlay several images.


The never-ending story …

Tuesday, October 28th, 2008

As a Mac user, I often get asked what is so special about Macs and “Isn’t it just because you want to be different and are deluded by their great design?”.

In this article I want to show you a few interesting facts that you might not have known. (more…)

Exercise 5 – Image manipulation

Thursday, October 23rd, 2008

In times of Photoshop you can never be sure whether a picture really reflects reality or is just a well-done fake. And then there are real pictures you would never believe aren’t manipulated. 

This post also looks 10 years into the future and tries to guess how I might look then.


Exercise 4 – Image composition

Wednesday, October 22nd, 2008

Learn how to create a stunning result by composing multiple images in Photoshop.


Exercise 4a – GIMP

Thursday, October 16th, 2008

Task 1: Replacing backgrounds

We start with a basic picture with a rather unexciting background.


We use the Fuzzy Select Tool (Photoshop users would refer to it as “the magic wand tool”) to select our background. Holding down the shift key adds further areas to the selection. 

When we are happy with it, we create a new layer mask by right-clicking on our background layer and choosing Add Layer mask … We want our selection to be the layer mask.

We’re almost done! The last step is to copy our new, shiny background into the picture:

Tadaah! The result looks as follows:

Task 2: Aurora Borealis

There is a great step-by-step tutorial on how to create a “Mac OS X Leopard”-like Aurora Borealis effect:

Here my result:

Task 3: Red Eye Removal

A very common task in the field of image editing is red eye removal. Most image editing programs include pre-defined RER filters. In this example, I show you how to use GIMP’s Red Eye Removal Tool and how to further improve your image.

Here is the picture we want to edit:

In GIMP, the feature to remove red eyes is under Filters -> Enhance -> Red Eye Removal …. Just applying this filter would not do the trick in this case. The color of the whole image would be altered. So we select each eye with the Ellipse Select Tool and create a layer mask for just that eye.  

Now we can apply our filter to both eyes individually which gives as a lot more flexibility.

But even with that done, the right eye still looks brighter than the left one. So we adjust the color by going to Colors -> Hue-Saturation until both eyes look similar.

Here is my final result:

Exercise 3b – Sound with Processing

Saturday, October 11th, 2008

Task 2: MP3-Player

The task was about creating a little MP3 player which is able to play mp3 and display the amplitude graphically. I added a few extra features so that for example the filename of the current track and its time are shown. The graph’s color and stroke weight are also dynamically changing.

View Applet / Source The mp3-file used in this example may take some time to load (0.9 MB).

Task 3: MIDI-Player

This applet plays a MIDI file and enables the user to pause the file. With the keys 1 to 9 you can also generate basic sounds.

View Applet / Source

Midi replay doesn’t yet work due to some problems with the paths. :-(

Task 4: Fourier Analysis

This is an extension to the simple MP3 player from Task 1. This one shows not only the amplitude, it displays also the frequencies by FFT (Fast Fourier transform).

View Applet / Source The mp3-file used in this example may take some time to load (0.9 MB).