Feature Extraction for face authentication

I need to extract and select features from a face image for face-authentication problem.

After completing face-detection, which features should I select? Please help me out with the code!

[Mert CÖMERT]

I also used Viola-Jones algorith to detect faces and then saved thse faces to the database and nowI'm waiting for the recognition part? Which algorithm or techniques can Iused?WEhich features of faces are important to identify people? I need help ,please.

[Saima Raza]

Too late reply,i am also working on similar problem ...though didn't code anything yet but i have a clear vision that i will go for lower part of face or lower feature like lips accordnig to my problem statment similar case applies to you ...you should emphasis on those features which must be helpful for your problem identification as wider eyes for happy face identification