UAV-based Spectrometer Enables Precision Agriculture
By plane, train, automobile — and now, unmanned aerial vehicle (UAV) – spectroscopy is on the move, escaping the confines of the lab and taking the measurement to the sample.
For Ocean Optics customers, the compact, lightweight STS microspectrometer has become the instrument of choice for a variety of UAV-based spectroscopy applications. With its low payload and minimal power consumption, STS can be integrated with off-the-shelf components and microcontroller platforms for remote measurements of vegetation, surface waters and more.
One of the early adopters of the STS for UAV-based measurements is Andreas Burkart, a postdoctoral plant researcher at the Research Center Jülich IBG-2 Plant Sciences in Germany. Burkart has integrated an STS into a UAV using Arduino open-source hardware and recently documented and published the project, which he calls ‘‘Specy,“ with detailed assembly instructions and firmware. (Ocean Optics makes available its own developers kit for STS that utilizes the Raspberry Pi microcontroller platform.)
Recently, Burkart weighed in on his work with spectroscopic analysis of vegetation and how UAVs are helping to change the landscape of remote sensing:
Ocean Optics: How is your work with UAV-based spectral sensing progressing? What insights have you gleaned just in the last year or so of work?
Burkart: My Ph.D. work was rather technical, so I learned that spectroscopy of vegetation in outdoor conditions is extremely demanding — not only because of the fluctuating light, but also because of the extremely vivid changes in plant canopies. However, it is totally worth it, because hidden in the spectra there is more information than we can actually understand. Some of the information refers to the biochemistry [of vegetation] and some is linked to the structure of the canopy. For deeper insights, please refer to my thesis Multitemporal assessment of crop parameters using multisensorial flying platforms.
Ocean Optics: In earlier interviews, you’ve described how data collected from UAV-based systems could help farmers take action to improve crop yields and avoid problems. What sort of examples of this have you been able to validate with your research?
Burkart: At the moment I’m still working on these, since we like to go very deep into the functional processes of plants. However, even companies have now started to go in this direction — for example, HEMAV in Spain. They actually use an STS on a drone. These companies generate UAV multi- or hyperspectral data, do the analysis and provide decision maps for the farmers. This is still in the beginning but already an interesting tool is being developed for farmers and breeders, and also for the government to check what’s happening in the fields.
Ocean Optics: What are the biggest challenges of using the UAV technology? Do researchers worry about any negative backlash against the use of UAVs because of security concerns?
Burkart: The missing legislation in most parts of the world is making trouble, as well as semi-professionals who regularly crash their UAVs and create bad publicity. In my opinion rotary wing UAVs will never really become absolutely reliable and safe tools. Once the research has been done, aerial coverage will be performed by UAV planes or even airships, which can be operated extremely safely.
Ocean Optics: There seems to be quite a bit of sophistication involved in making UAV-based spectroscopy measurements. How far off are these UAV systems from being simple enough for farmers to use?
Burkart: Basic imaging of agricultural fields can already be done by any farmer simply and quickly. This birds-eye view already gives some basic insight and can help a lot. However, complicated spectral analysis will be performed by service companies in the future. Another way is that spectral systems like the N-Sensor [a precision agriculture system for crop fertilization] will be attached to a tractor and automatically run the analysis on demand, during normal driving.
Ocean Optics: Have scientists other than plant researchers contacted you with questions about using UAV-based systems for their own work? What sort of applications are they tackling?
Burkart: Yes, I get every week or two some questions regarding hyperspectral measurements from a UAV. However, these are usually working toward imaging spectrometers, which face a lot more problems than point sensors have. These applications typically involve agriculture, ecosystem monitoring, water science and forest management. Actually, there are at the moment already about 10 STS with Arduino systems out there doing interesting things on UAVs, tractors and even submarines.
- Compact Spectrometers for Remote Sensing of Grassland
- UAV-capable Microspectrometers for Analysis of Vegetation and Ground Cover
Development Tools and Projects
- Specy – an autonomous spectroscopy system
- SPECY – Arduino and Ocean Optics STS Spectrometer
- STS Developers Kit