Untersuchungen zur Laserlichtwirkung auf der Basis von Bildanalysen auf juvenile Pflanzen zur Unkrautregulierung

• Applicants: Professor Dr.-Ing. Stephan Barcikowski, since 8/2010; Professor Dr. Thomas Rath
• Subject Area: Plant Cultivation, Plant Nutrition, Agricultural Technology
• Term: from 2009 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 148337920

Non-chemical weed control is an essential objective of an ecological and sustainable plant production. A future alternative might be the specific weed control of plants in early growth stages using laser technology. The objective of the applied research project is to enlarge upon a laser based weed management in an interdisciplinary research approach of bio systems and laser engineers. Thereby, the promising results of the first project phase provide the basis. After the development of a damage model depending on laser technical and plant cultivation parameters, an image acquisition and processing system could be designed. As the optimal targeting points could be determined, the laser beam was accordingly positioned. Ongoing experiments currently determine the limit values of the laser application concerning the weed density and the operating speed. The focus of the renewal proposal lies on the transferring of the results to complex conditions. The key challenges are the steps from a laboratory environment to applications in the field. The image acquisition and processing as well as the laser beam positioning will be optimized with the environmental dynamisation, as tilting and vibration will be considered. This improvement aims at a reliable and fast detection of weed plants between and in plant rows. Thereby, the separation quality is investigated under overlapping situations as well as with diverse plant species and growth stages. To do this, surveys of real weed abundances are necessary, allowing the acquisition of training datasets for individual weed species regarding morphological characteristics of early growth stages. Specific active-shape-models will be designed which are able to determine an ideal targeting close to the meristem based on single leaf shape and phyllotaxis. The inclusion of height information via 3D-cameras is advantageous, while the influence of the camera specifics shall be investigated. The classification of detected plants will be optimized respecting fast decisions to minimize delays for the derived laser beam positioning.The targeting bases on global coordinates, to which the camera as well as the galvanometer is calibrated. In contrast to the controlled laboratory conditions the laser machining head will be placed far away from the soil layer under rough environment conditions. Respecting the angular resolution of the actuators, a spatial correction matrix is created. The development of a tracking of the laser beam position along the moving direction allows on-the-fly irradiations with adapted exposure times.After the installation of the system on to a mobile platform, even more complex driving events occur. These include beside vibrations also tilting and drifting. During the driving, corrections of the targeting shall be considered in order to avoid false hits. The compensations shall be supported by appropriate bearing as well as by tilt and acceleration sensors.

• DFG Programme: Research Grants
• Participating Person: Professor Dr.-Ing. Heinz Haferkamp (†)
• Ehemaliger Antragsteller: Dr.-Ing. Dirk Herzog, until 7/2010