There are many solutions that do this, both proprietary and Open Source. Accuracy is influenced by lots of factors, some to do with the setup (camera angle, lig

There are many solutions that do this, both proprietary and Open Source. Accuracy is influenced by lots of factors, some to do with the setup (camera angle, lighting) the hardware (camera quality, computation speed) and the subjects (race, facial hair, glasses). We used this in research projects involving elderly mood assessment and in television viewer's emphatic responses. The package we used was marketed by Noldus ( http://noldus.com http://noldus.com ) and developed bu Vicarvision ( http://vicarvision.nl http://vicarvision.nl ), but most of these packages perform at about the same level.