Using the open sourced facial recognition Open CV, I successfully implemented face masking using textures over webcam images. This was an eye-opening project for me and I had real fun creating this effect. The project was built in unity3d.
This same logic is being used for a multimedia project my company was commissioned for.
Wewejune 
i wanna know about this technique , can you email for me ?
please
Hey Hyun Soo, i used OpenCV for Unity. You can find it in the unity asset store. They have an example in the package that demostrates this. https://www.assetstore.unity3d.com/en/#!/content/21088
It is great, but I also downloaded the opencv plugin for unity, but did not find such demo, could you please share which module you are using? Many many thanks.
Hello Rex, the same team for the opencv also released a face tracking demo. You can check it out here: https://www.assetstore.unity3d.com/en/#!/content/35284