A system and method for detecting an obstacle comprises determining a vegetation height of a vegetation canopy at corresponding coordinates within a field. An object height is detected, where the object height of an object exceeds the vegetation height. A range of the object is estimated. The range of the object may be references to a vehicle location, a reference location, or absolute coordinates. Dimensions associated with the object are estimated. An obstacle avoidance zone is established for the vehicle based on the estimated range and dimensions.