Posture ? Can you filter/brief your area of research ? I presume that it's related to human body... For instance Gait or Gesture analysis... Instead of going for any open source.. API's such as LabVIEW may help you lot like live streaming tracking of gestures/ movements and post processing is also easier.. If you can explain the kind of posture that you're intended to track, we may help you still more clearly !

I'm interested in an algorithm that I can use for human activity recognition and that can make use of cameras in different places without knowing the configuration. Although there are many ways to do this, I rather use an algorithm that infers the activity from a sequence of postures in 3D space. It may be too much to ask for.