Most 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.
This week’s post is all about colors and how you can use code to work with them. We create a color picker and apply color filters to an image to create a neat effect.
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.
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. Read the rest of this entry »
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.
Learn how to create a stunning result by composing multiple images in Photoshop.
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:
There is a great step-by-step tutorial on how to create a “Mac OS X Leopard”-like Aurora Borealis effect: http://www.abduzeedo.com/leopards-aurora-borealis-wallpaper-gimp
Here my result:
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:
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).
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.
Midi replay doesn’t yet work due to some problems with the paths. 
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).
Audacity is free, open source software for recording and editing sounds.
To use Audacity’s Noise Removal effect, you start by selecting a few seconds of noise. Then go to Effect -> Noise Removal… and click Get Noise Profile. The dialog closes and you return to your file. Select the whole track and again, open the Noise Removal dialog. This time you can chose the degree and you can perform some fine-tuning.
When you are happy with the result, click Remove Noise and voilà, your noise is gone.
In my example I also applied another effect called Normalize in order to boost the volume a little bit.
Example Before (strong background noise): mixed.mp3 – Before
After noise removal: mixed. mp3 – After
Definition Bit Rate (http://en.wikipedia.org/wiki/Bit_rate):
In digital multimedia, bit rate often refers to the number of bits used per unit of playback time to represent a continuous medium such as audio or video after source coding (data compression). The size of a multimedia file in bytes is the product of the bit rate (in bit/s) and the length of the recording (in seconds), divided by eight. In case of streaming multimedia, this bit rate measure is the goodput that is required to avoid interrupts. …Audio (MP3)
- 32 kbit/s — MW (AM) quality
- 96 kbit/s — FM quality
- 128–160 kbit/s — Standard Bitrate quality; difference can sometimes be obvious (e.g. bass quality)[citation needed]
- 192 kbit/s — DAB (Digital Audio Broadcasting) quality.[citation needed]
- 224–320 kbit/s — Near CD quality.
For this task, I tried to overlay the songs “Put Your Hands Up For Detroit” and “Let Me Think About It” by Fedde Le Grand in Audacity. Here is what I did:
1. File -> Open … “Put Your Hands Up For Detroit.mp3″
2. Go to Project -> Import Audio… and select the second song ”Let Me Think About It.mp3″.
3. Adjust Tempo by selecting a track and going to Effect -> Tempo… This changes the tempo without changing the pitch, so your song won’t sound like Mickey Mouse. It may take some trial and error until you get the right tempo.
4. With the aid of the Time Shift Tool you can easily move the tracks until they match. The Envelope Tool can be used to create a nice fade in and fade out effect.
Result:
Due to legal issues I’m not allowed to publish the result here. If you’ve got further questions, just leave a comment or contact me.Exercice 2a: Random black lines on a gray background.
Exercice 3b: Rotating Globe with changeable direction on mouse click.
Hello. My name is Andy Abgottspon, 23, from Visp in Switzerland. I'm currently studying Informatics at Coventry University (UK) in my final year. My interests include everything from webdesign, graphics, games programming to video editing and playing football.
