Eulerian Video Magnification(EVM) is a way to reveal subtle changes in the world. With this method you can directly see a man's pulse, or the vibration of a camera while taking photo, etc.Here's an example: http://www.youtube.com/watch?v=e9ASH8IBJ2U
This Github project provide a C++ implementation of EVM, based on OpenCV and Qt.
https://github.com/wzpan/qtevm