The laser beam can be used to selectively fight weeds in an early growth stage. This is the result of a current research project between the Laser Zentrum Hannover (LZH) and the Biosystems and Horticultural Engineering (BGT) faculty of the Leibniz Universität Hannover.
Exact positioning of the laser beam (shown here in red) on weed model plants in a laboratory setting
More and more, environmentally safe methods are being used to rid fields used for agricultural and horticultural of unwanted plants, or weeds. Chemical pesticides can be used selectively and are suitable for use where conventional, thermal methods such as flaming are either not exact enough, or are too energy consuming. However, drift and overdosing often lead to harmful herbicide residues in the top soil layers, or in surface water. By using an exact, selective laser beam, the growth of weeds can be impaired by destroying the sensitive growth centers of the plants, their so-called meristems. Current laboratory results show that a minimum dose of around 35 Joules is necessary to kill seedlings, and this laser energy can be exactly and effectively adapted to the plant species and growth stage.Researchers from the LZH Department of Materials and Processes, Safety Technology Group are using a CO2 laser in the infrared range with a wavelength of 10.6 µm in their current investigations. The laser radiation has a direct thermal effect on the plants. By using a galvanometer scanner with a flexible mirror system, the laser beam can be moved quickly from plant to plant, and can be focused with high precision on the near-surface meristems. Under laboratory conditions, an accuracy of
A stereo camera system is used to recognize the plants and optimize the position of the laser beam. After using a complex processing method, scientists of the BGT have compared camera images based on threshold level filtering and edge detection, with Active Shape Models of the plants. The position of the leaves can be used to determine exactly where the meristem position is, and once these coordinates are found, a signal is sent to the laser to “hit the target”.
Scientists at the LZH have been able to determine exactly how much energy is needed to achieve an optimal effect on the target, making this method especially efficient. At the moment, different irradiation times in different weed concentrations are being tested concerning economic viability. Current knowledge shows that the best results for large areas can be provided by using autonomous field robots working in a stop-and-go mode.
The project „Investigations on the Effect of the Laser Beam on young Plants for Weed Control using Image Processing“ is subsidized by the German Research Foundation (DFG).
Michael Botts | Laser Zentrum Hannover e.V.
Rutgers scientists discover 'Legos of life'
23.01.2018 | Rutgers University
Researchers identify a protein that keeps metastatic breast cancer cells dormant
23.01.2018 | Institute for Research in Biomedicine (IRB Barcelona)
Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.
Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
23.01.2018 | Life Sciences
23.01.2018 | Earth Sciences
23.01.2018 | Physics and Astronomy