Algorithm to extract face properties for face recognition neural network

Algorithm to extract face properties for face recognition neural network

i'm doing an project for college, i need to create back propagation neural
network which will recognize the faces. For this purpose i'm allowed to
use an algorithm in C# which will extract the face properties from input
image, which will I later use as inputs of neural network. Can you
recommend me some which is good, or one which is usual for usage with
neural networks?
Just to be clear: i don't need algorithm which will actually recognize
face on the image,just to get the characteristic properties of the face in
image. Images are going to be of same dimensions, faces photographed
frontally.