D5 · Seeing
How Much Can This Neuron See?
Compute the receptive field of a unit deep in a stack, and say why downsampling is what makes it grow.
Pick one number deep inside a trained network. Which pixels of the photo could have changed it? The answer is a square, called the unit's receptive field (Receptive Field). The name comes from brain science. A cat that does not fit in that square is invisible to the unit.