  Autonomous navigation is a pre-requisite for field robots to carry out
precision agriculture tasks. Typically, a robot has to navigate through a whole
crop field several times during a season for monitoring the plants, for
applying agrochemicals, or for performing targeted intervention actions. In
this paper, we propose a framework tailored for navigation in row-crop fields
by exploiting the regular crop-row structure present in the fields. Our
approach uses only the images from on-board cameras without the need for
performing explicit localization or maintaining a map of the field and thus can
operate without expensive RTK-GPS solutions often used in agriculture
automation systems. Our navigation approach allows the robot to follow the
crop-rows accurately and handles the switch to the next row seamlessly within
the same framework. We implemented our approach using C++ and ROS and
thoroughly tested it in several simulated environments with different shapes
and sizes of field. We also demonstrated the system running at frame-rate on an
actual robot operating on a test row-crop field. The code and data have been
published.
