Self-recharging robots

Several companies are working on taking recharging to the next level - Robots that locate wall sockets and plug themselves in. The robot has several sensors and an arm that locate the socket and plug into the socket.

This got me wondering, can there be a machine-vision-only solution to this problem? A socket should be a very easily distinguishable thing. Hmm... could the Scale Invariant Feature Transform do this trick? Or will simple template matching work?

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