ofxFaceTracker is openFrameworks addon for face tracking, based on Jason Saragih's FaceTracker library.
openFrameworks is an open source toolkit for creative coding.
FaceTracker is open source for non-commercial use, and is available from Jason directly. One you have Jason's source, you'll need to drop it in libs/ (e.g., libs/Tracker/Tracker.h). You'll also need to drop the model data in bin/data/model/. If you see the error Assertion failed: s.is_open(), that means you forgot to drop the model files in the right folder.
If you would like to prototype an idea involving face tracking, I encourage you to download FaceOSC. Dan Wilcox has some great FaceOSC templates that will help you get started in environments like Max, pd, Processing, and openFrameworks.
If you're interested in using ofxFaceTracker for face substitution, check out the FaceSubstitution repository.
Demonstrates how to get the image-space position of the face, and the 3d orientation (collectively, the face "pose") then applies these to the OpenGL context in order to draw an oriented face mesh.
An advanced example that shows how you might detect blinking from the extracted eye images. This is not necessarily a robust classifier for whether eyes are open or closed, but works well for blinks as events.
Fairly complicated example that demonstrates some advanced/experimental features of ofxCv and ofxFaceTracker for doing AR-style augmentation of the face.
Provides a minimal example of using an ofxVideoGrabber with an ofxFaceTracker, then extracts and draws the ofPolyline representing the left and right eyes.
Demonstrates the ExpressionClassifier, which can load, save, and classify expressions into pre-trained categories. Provides basic expressions (eyebrows raised, neutral, smiling) as examples.
Demonstrates how to use the mean face mesh to draw pose and expression normalized representation of the face currently being tracked.
Sends as much data as possible from ofxFaceTracker via OSC, including various "gestures", position, and orientation.