ABSTRACT

Vehicle automation requires the constant acknowledgment of the neighboring space, but the specic parameters and properties to be tracked highly depend on the type of environment in which each vehicle operates, as well as the particular tasks commanded to the vehicle in the mission pursued. So, for example, the wind speed is a key factor to be considered in the automated landing of aerial vehicles but has negligible inuence in the path-planning control algorithm of a farming tractor. Agricultural applications and environments are quite diverse, although the perceptual needs of farm machinery can be grouped into two general sets: sensing for crop production status and sensing for navigation and positioning. The rst group includes mapping of soil properties, detection of water stress in crops, estimation of plant vigor, monitoring of nitrogen shortage in leaves, and assessment of fruit maturity or plant diseases. The second set involves all perceptive means-visual and nonvisual-of positioning the vehicle with respect to surrounding obstacles, as well as the precise operation of implements such as the automatic maneuver of unloading side pipes in harvesters. The size, power, and weight of farm equipment make autonomous navigation very complex, not only because machines are oversized and lanes become tight, but also because of the high levels of reliability required; an accident caused by an autonomous vehicle will surely jeopardize further research and innovation in this discipline for years. Yet, there exist plenty of advantages in the development of semiautonomous machines, that is, vehicles that are capable of performing automated tasks under the supervision of a human operator granting safety. Even the minimum degree of autonomy will require a sound perception system to

12.1 Perception Needs in Agricultural Environments .......................................... 323 12.2 Two-Dimensional Perception for Navigation and Monitoring ..................... 325 12.3 Three-Dimensional Awareness for Navigation and 3-D Mapping ............... 329 12.4 Global Maps from Local Perception ............................................................ 334 12.5 Future Steps in Surrounding Awareness ...................................................... 339 References ..............................................................................................................340