Vision-only outdoor localization of two-wheel tractor for autonomous operation in agricultural fields

This paper outlines the problem of outdoor autonomous robot localization for agricultural operations. Vision based outdoor localization system is developed entirely of off-the-shelf components that can accurately guide a field robot in small agricultural fields. Visual odometry using downward faced camera is proposed as a high resolution relative localization system. A stereo vision based range measurement system is also developed and field tested as an absolute localization system that can bound the incremental error caused by the visual odometry system. The extended Kalman filter with measurement gating is implemented using both visual odometry and stereo range measurement data. Field tests demonstrated proposed system is capable of localization of two wheel tractor at a very low cost with acceptable accuracy in small agricultural fields.