You've probably seen/heard about the sophistication technology that accessing computers using face authentication? face is scanned through a video camera and if the face was recognizable in the database then you will be able to access computers or go into the room they will be.
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Now with ubuntu technology we can do it, some requirements that must be filled is in your computer must have a video camera / webcam and some library tobe install. How to make automatic login using face authentication, follow step bellow :

Add the PPA repository and Update
  • sudo apt-add-repository ppa:antonio.chiurazzi/ppa && sudo apt-get update
 Install the Ubuntu  Face Authentication /  Face Recognition Library
  • sudo apt-get install pam-face-authentication
Tweak and Edit The System
Now to add the face authentication module to GDM, Ubuntu's default login-manager:
  • sudo sed -i '1i auth sufficient pam_face_authentication.so enableX' /etc/pam.d/gdm 
  • sudo sed -i '1i auth sufficient pam_face_authentication.so enableX' /etc/pam.d/gnome-screensaver
Depending on your webcam model/make you may need to install and add libv4l to preload:
  • Create the file /etc/ld.so.preload
  • Paste in the path to the v4l1compat.so file commonly found in /usr/lib/libv4l
Open "Face Trainer" (Application > Other), system will scan your face and add to database so that the system recognize your face while logi

Go  to  System > Administration > Users and Groups
, change the password to Asked to login

Go to System > Administration > Login Screen
, choose "Show the Screen for choosing who will log in", whis action will disable automatic login.
 
Done, you can  logoff  the system and test face authentication login in your ubuntu.