With consumer grade digital camera technology approaching 10-million picture element (pixel) resolution and personal computer technology approaching 4-gigahertz clock speeds, ground-based machine vision weed detection has the potential to provide high resolution mapping of individual plants for automated real-time control of weeds in agricultural fields. This paper will discuss the concept of an autonomous robotic weed control system and review the current status of its three core technologies: machine vision weed detection, precision microspraying, and RTK-GPS-based autonomous (i.e. unmanned) vehicle guidance.