How do image distortion applications like the 'Booth' series work?

I just wanted to开发者_StackOverflow中文版 know how all of the iPhone/iPad 'Booth' applications (i.e FatBooth, BaldBooth, SkinnyBooth) work. How do they do their image distortion?

---

It's image processing.

First you need to find the face of the person.

Then you process the face with an algorithm or a layer to add effects.

You should take a look at OpenCV framework ( http://opencv.org/ ) for face recognition (and opencv forums to get ideas ^^).

Good luck.