More than a year ago, I was playing with some Computer Vision algorithms, and I posted this: Active Appearance Models in C++ (Paamela). The framework I built back then was a bit more complete than a simple AAM implementation, and actually I went up to the point where I was able to transform the sex, age and ethnicity of a person in a picture. The code was basically sitting there, taking dust in my hard drive. I had been willing to try some Objective-C and mobile development for some time. With the use of some magic (and good cross-compiling skills), I have been able to port the code from Linux to the iPhone. I now have a fully functioning facial transformation framework running on the iPhone!
