set of convolutional and fully connected layers ordered suchthat the output of one layer is the input of the next. For imagedata, the ﬁrst layers of the network typically learn low-levelfeatures such as edges and corners, and further layers learnhigh-level features such as textures and objects (Zeiler andFergus 2013). Taken as a whole, a CNN is a mapping fromtensors to feature vectors, which become the input for a ﬁnalclassiﬁer. A typical convolutional layer maps a tensor x∈