In [ ]:

#hide
!pip install -Uqq fastbook
import fastbook
fastbook.setup_book()

In [ ]:

#hide
from fastbook import *

[[chapter_cam]]

CNN Interpretation with CAM

Now that we know how to build up pretty much anything from scratch, let’s use that knowledge to create entirely new (and very useful!) functionality: the class activation map. It gives us some insight into why a CNN made the predictions it did.

In the process, we’ll learn about one handy feature of PyTorch we haven’t seen before, the hook, and we’ll apply many of the concepts introduced in the rest of the book. If you want to really test out your understanding of the material in this book, after you’ve finished this chapter, try putting it aside and recreating the ideas here yourself from scratch (no peeking!).