Apparently Samsung has developed an actual autonomous sentry gun that tracks and recognizes humans. The device is intended for deployment in the DMZ between N and S Korea. Included in the article is a nifty video that's both funny and yet very...disturbing.
However, the following line pretty much sums it up, methinks:
It has a sophisticated pattern recognition which can detect the difference between humans and trees, and a 5.5mm machine-gun.Oh boy. It can tell the difference between trees and humans.
And it has a gun.
("Mr. Oak, put down your branches. You have 20 seconds to comply...")