kind of have to define a set of features that you're looking for in the image now the key idea of deep learning is that you will need to learn these features just from raw data so what you're going to do is you're going to just take a bunch of images of faces and then the deep learning algorithm is going to develop some hierarchical representation of first detecting lines and edges in the image using these lines and edges to detect corners and eyes and mid-level features like eyes noses mouths ears then composing these together to detect