A bob-based beat tracker

This is just a small proof of concept of a beat tracking system based on the visual input of a person bobbing the head with the rhythm of the music. The app is built with openFrameworks and uses the ofxCv addon to interact with OpenCV.

The logic of the program is based on the idea of following the head of the person using Viola-Jones object detection and identifying sudden changes in the velocity. There is also some Kalman filtering to smoothen things a bit. When some reasonable beat duration is inferred, the tempo is shown on the screen. Slow tempos are somewhat tracked, faster tempos not so much :(

The program does not require any special controls, but you can press key d to hide the visual tracking information. Pressing m toggles a visual metronome that does not work nearly as well as it should; beat phase seems to be harder to grasp.