facial expression recognition for ios

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I am using OpenCV to develop an iPhone application, and I am using it to detect faces. Rather than detect the face as a whole, I would like to detect each of the smaller facial features (eyes, nose, ears, lips, etc.). Actually,I want to do something like this link

How to use aam-opencv for iOS?

I searched on internet and I found this link

But I don't know how to apply this on iOS. Please, can you help me about facial expression recognition?