I used to put on my tinfoil hat and imagine that cryptography was the field to study if you wanted secret government agents to visit you. Maybe next time I will

I used to put on my tinfoil hat and imagine that cryptography was the field to study if you wanted secret government agents to visit you. Maybe next time I will instead imagine that computer vision is what summons the secret agents. More seriously, computer vision is going to be important and it appears to be far less known than machine learning and has higher barriers to entry. I'd exchange a few introductory machine learning books for more good computer vision introductions. Any suggestions on how to get started with computer vision?