How to recognize face by geometric feature such as eyes,nose,mouth?

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Now I extract the geometric feature from people face,as following picture show: I mark the interesting points,as follow: I calculate the distance between (s5,s6),(s1,s2),(s1,s7),(s2,s7),(s3,s7),(s4,s7),then divide by the distance from the midpoint of s1 and s2 to the midpoint of s3 and s4. I want to use the distance ratio to classify the faces,because I think the faces belong to the same person,the above distances will be nearness.

Unfortunately this way is not OK,and can not classify faces belong to different people,the different people's face,the above distance may also be nearness.

Now How can I use the geometric feature to do this work.

Looking forward to your reply！

Best Regards!