Evaluating the accuracy of mapping weeds in fallow fields using airborne digital imaging: Panicum effusum in oilseed rape stubble

The potential accuracy of using airborne multispectral imaging to map weed patches rapidly in a fallow held has been evaluated. An image of a field of oilseed rape (Brassica napus L.) stubble interspersed with Panicum effusum R. Br. was acquired using a four-camera airborne digital imaging system; r ecording in the infrared, red, green and blue wavebands. The image was conv erted into georectified weed maps using supervised and unsupervised classif ication procedures. Comparison of the airborne-derived maps with an accurat e weed map compiled from a detailed ground survey demonstrated that weed:no n-weed classification and mapping accuracies of better than 87% are possibl e. The limitations of assessing the accuracy of classified imagery using gr ound-truth data of similar spatial resolution are discussed.