Capsule networks were introduced by Geoffrey Hinton as a way to overcome some of the limitations of standard CNNs. To understand the idea behind capsule networks, we need to understand these limitations first.
Capsule networks
Limitations of convolutional networks
Let's start with a quote from professor Hinton himself:
"The pooling operation used in convolutional neural networks is a big mistake and the fact that it works so well is a disaster."
What he means is that the CNNs are translation-invariant. To understand this, let's imagine a picture with a face, located in the right half of the picture. Translation invariance means that a CNN is very good at telling us that the picture contains a face, but...