Precision Agriculture, 4, 5–18, 2003 © 2003 Kluwer Academic Publishers. Manufactured in The Netherlands. Development of an Image Processing System and a Fuzzy Algorithm for Site-Specific Herbicide Applications CHUN-CHIEHYANG chun-chieh.yang@mcgill.ca Postdoctoral Fellow, Department of Agricultural and Biosystems Engineering, McGill University, Ste-Anne-de-Bellevue, QC, Canada SHIVO.PRASHER prasher@macdonald.mcgill.ca Professor, Department of Agricultural and Biosystems Engineering, McGill University, Ste-Anne-de-Bellevue, QC, Canada JACQUES-ANDRÉLANDRY landry@macdonald.mcgill.ca Assistant Professor, Department of Agricultural and Biosystems Engineering, McGill University, Ste-Anne-de-Bellevue, QC, Canada HOSAHALLIS.RAMASWAMY ramaswamy@macdonald.mcgill.ca Department of Food Science and Agricultural Chemistry, McGill University, Ste-Anne-de-Bellevue, QC, Canada Abstract. In precision farming, image analysis techniques can aid farmers in the site-specific application of herbicides, and thus lower the risk of soil and water pollution by reducing the amount of chemicals applied. Using weed maps built with image analysis techniques, farmers can learn about the weed distribution within the crop. In this study, a digital camera was used to take a series of grid-based images covering the soil between rows of corn in a field in southwestern Quebec in May of 1999. Weed coverage was determined fromeachimageusinga“greennessmethod”inwhichthered,green,andblueintensitiesofeachpixelwere compared. Weed coverage and weed patchiness were estimated based on the percent of greenness area in the images.Thisinformationwasusedtocreateaweedmap.Usingweedcoverageandweedpatchinessasinputs, afuzzylogicmodelwasdevelopedforuseindeterminingsite-specificherbicideapplicationrates.Aherbicide applicationmapwasthencreatedforfurtherevaluationofherbicideapplicationstrategy.Simulationsindicated thatsignificantamountsofherbicidecouldbesavedusingthisapproach. Keywords: image processing, fuzzy logic, precision farming, herbicide application, weed map Introduction In conventional weed management, herbicides are applied uniformly to a field in sig- nificant amounts. The over application of agrochemicals, which can damage crops, has become one of the main sources of non-point source pollution (Mannion, 1995). The extraagrochemicalsremaininthesoil,leachintothegroundwateranddrainintosurface waterbodies(SmithJr.etal.,1995).Consequently,itisbecomingincreasinglyimportant toprotecttheenvironmentfromthispollution,byreducingtheapplicationofherbicides.