It’s possible to add noise to an image that the human brain filters out, but that will cause computers to misclassify it.

Slight Street Sign Modifications Can Completely Fool Machine Learning Algorithms

From the still-needs-work department: It’s possible to add noise to an image that the human brain filters out (or doesn’t even notice), but that will cause computers to misclassify it. Amusing when you’re sorting photos of animals, but dangerous when it convinces a self-driving car that a stop sign is simply reporting a speed limit.