Facial recognition software may be nothing new but did you know you can use your regular ol' webcam to log in to your Ubuntu desktop?
Logging in to Ubuntu with nothing more than a smile is possible using the pam-face-authentication utility which was specifically designed for regular everyday users to use.

How to install facial recognition tool in Ubuntu

1. Install the dependencies required to run the face recognition tool. You can install that by executing the  following command in terminal. To open  Terminal go to Applications > Accessories > Terminal. The commands are different for Lucid Lynx and Maverick Meerkat users:
Lucid Lynx users: -

sudo apt-get install build-essential cmake qt4-qmake libx11-dev libcv-dev libcvaux-dev libhighgui4 libhighgui-dev libqt4-dev libpam0g-dev libswscale0

Maverick Meerkat users:

sudo apt-get install build-essential cmake qt4-qmake libx11-dev libcv-dev libcvaux-dev libqt4-dev libpam0g-dev libswscale0 libhighgui-dev libhighgui2.1

2. Install the face recognition tool by executing the following commands:
          sudo su
3. Run the ‘Face Trainer’ application from the Applications > Other menu.

Steps to add face recognition tool to GNOME display manager (GDM):

For the face login feature to be added to your default GNOME display manager you should execute the following sudo commands:

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 v411compat.so file commonly found in /usr/lib/libv4l