A robot has been invented that can weed crops. The robot strolls down crop rows, distinguishing between weeds and the good plants, removing the weeds. It was invented by a Swedish guy from Halmstad University, named Björn Åstrand (the abstract for his PhD thesis is here). In a world where weeding takes place by hand, an invention like this could save thousands of man-hours, and money (it costs about $500USD/acre to weed an "ecological" farm).

One camera directs the robot, while another looks at plants and uses a software program to distinguish good plants from bad ones. Currently, the system is susceptible to changes in how the plants look and other environmental factors, like rain.

To combat this, Björn says:

“I have therefore developed another technique that also reads the cultivation patterns of crops. Since crops are planted at regular intervals, such as fifteen centimeters apart, the computer can determine what is a weed and what isn’t. By combining these different methods we achieve a robust technology.”

Here’s a report on the robot from a Swedish source.