Convolutional Neural Networks (CNN) Block Diagram refers to a sub-category of neural networks: they have all the characteristics of neural networks. Their architecture is more specific as it is composed of two main blocks. The first block shows the particularity of this type of neural network since it functions as a feature extractor. To do this, it performs template matching by applying convolution filtering operations. The second block is, in fact, at the end of all the neural networks used for classification. The input vector values are transformed (with several linear combinations and activation functions) to return a new vector to the output.