9Slaughter D C, Giles D K, Downey D.Downey.Autonomous robotic weed control systems:a review [J]. Computers and Electronics in Agricuhnre,2008,61(1):63-78.
10Tumbo S D, Salyanim, Whitney J D, et al. Investigation of laser and ultrasonic ranging sensors for manual measurements of citrus tree canopy volume [J]. Applied Engineering in Agriculture,2002,18(3):367-372.