Andreas Burkart

JB Hyperspectral Devices · HQ

Sun-induced chlorophyll fluorescence (SIF) has recently emerged as a proxy for canopy photosynthesis of vegetation and offers a promising approach for scalable remote crop monitoring. Effective application of SIF for crop monitoring requires better understanding of the processes that cause SIF-photosynthesis decoupling at leaf and canopy scales. To...

Sentinel-2 satellite data enables multispectral monitoring of the earth at a high temporal revisit rate. Combining this information with a network of optical ground measurements enables a more detailed and a more complete understanding of terrestrial ecosystems. However, independent optical ground measurements often lack consistency , especially wh...

Sun-induced chlorophyll fluorescence (SIF) has recently emerged as a proxy for canopy photosynthesis of vegetation and offers a promising approach for scalable remote crop monitoring. Effective application of SIF for crop monitoring requires better understanding of the processes that cause SIF-photosynthesis decoupling at leaf and canopy scales und...

This article introduces a novel stereo-camera system for the measurement of solar-induced chlorophyll fluorescence (SIF) at 760 nm. The instrument uses optical interference filters to gain high background radiation-suppression in the telluric oxygen absorption band at 760 nm, to measure the weak SIF signal. Featuring spatially high-resolution image...

A hyperspectral field sensor (FloX) was installed in Ad�ventdalen (Svalbard, Norway) in 2019 as part of the Svalbard Integrated Arctic Earth Observing System (SIOS) for monitoring vegetation phenology and Sun-Induced Chlorophyll Fluorescence (SIF) of high-Arctic tundra. This northernmost hyperspectral sensor is located within the footprint of a tow...

Non-invasive investigation of surfaces from drones and manned aircrafts used as camera platforms is a well-established remote-sensing practice. However, cross-comparison of multispectral reflectance from different camera systems across different platforms, locations, and times can be challenging. We investigate reflectance retrieved from Sentinel-2...

In this paper, we present GrowliFlower, a georeferenced, image‐based unmanned aerial vehicle time‐series dataset of two monitored cauliflower fields (0.39 and 0.60 ha) acquired in 2 years, 2020 and 2021. The proposed dataset contains RGB and multispectral orthophotos with coordinates of approximately 14,000 individual cauliflower plants. The coordi...

Remote sensing employs solar-induced chlorophyll fluorescence (SIF) as a proxy for photosynthesis from field to airborne and satellite sensors. The investigation of SIF offers a unique way of studying vegetation functioning from the local to the global scale. However, the passive, optical retrieval of the SIF signal is still challenging. Common ret...

The upcoming Fluorescence Explorer (FLEX) satellite mission aims to provide high quality radiometric measurements for subsequent retrieval of sun-induced chlorophyll fluorescence (SIF). The combination of SIF with other observations stemming from the FLEX/Sentinel-3 tandem mission holds the potential to assess complex ecosystem processes. The calib...

Earth system sciences investigate dynamic processes and cycles of materials which follow distinctive timings towards a better understanding of climate and biosphere interaction. Phenology of vegetation reveals specific temporal pattern for different vegetation types and is affected by abiotic environmental influences. Changing abiotic factors relat...

This article presents GrowliFlower, a georeferenced, image-based UAV time series dataset of two monitored cauliflower fields of size 0.39 and 0.60 ha acquired in 2020 and 2021. The dataset contains RGB and multispectral orthophotos from which about 14,000 individual plant coordinates are derived and provided. The coordinates enable the dataset user...

Riparian zones fulfill diverse ecological and economic functions. Sustainable management requires detailed spatial information about vegetation and hydromorphological properties. In this study, we propose a machine learning classification workflow to map classes of the thematic levels Basic surface types (BA), Vegetation units (VE), Dominant stands...

Chlorophyll fluorescence (ChlF) information offers a deep insight into the plant physiological status by reason of the close relationship it has with the photosynthetic activity. The unmanned aerial systems (UAS)-based assessment of solar induced ChlF (SIF) using non-imaging spectrometers and radiance-based retrieval methods, has the potential to p...

Up-to-date information about vegetation types and hydromorphological structures and features are essential for the management of waterways. They are e.g. used for the monitoring and reporting of riparian statuses and their changes e.g. after river restoration and consequently, numerous man-days are spent on field surveys. To allow for an effective...

Hyperspectral remote sensing (RS) provides unique possibilities to monitor peatland vegetation traits and their temporal dynamics at a fine spatial scale. Peatlands provide a vital contribution to ecosystem services by their massive carbon storage and wide heterogeneity. However, monitoring, understanding, and disentangling the diverse vegetation t...

Hyperspectral remote sensing (RS) provides unique possibilities to monitor peatland vegetation traits and their temporal dynamics at a fine spatial scale. Peatlands provide a vital contribution to ecosystem services by their massive carbon storage and wide heterogeneity. However, monitoring, understanding, and disentangling the diverse vegetation t...

Growing interest in the proximal sensing of sun‐induced chlorophyll fluorescence (SIF) has been boosted by space-based retrievals and up-coming missions such as the FLuorescence EXplorer (FLEX). The European COST Action ES1309 “Innovative optical tools for proximal sensing of ecophysiological processes” (OPTIMISE, ES1309; https://optimise.dcs.aber....

Imaging and non-imaging spectroscopy employed in the field and from aircraft is frequently used to assess biochemical, structural, and functional plant traits, as well as their dynamics in an environmental matrix. With the increasing availability of high-resolution spectroradiometers, it has become feasible to measure fine spectral features, such a...

Unmanned aerial vehicles (UAVs) open new opportunities in precision agriculture and phenotyping because of their flexibility and low cost. In this study, the potential of UAV imagery was evaluated to quantify lodging percentage and lodging severity of barley using structure from motion (SfM) techniques. Traditionally, lodging quantification is base...

There is a critical need for sensitive remote sensing approaches to monitor the parameters governing photosynthesis, at the temporal scales relevant to their natural dynamics. The photochemical reflectance index (PRI) and chlorophyll fluorescence (F) offer a strong potential for monitoring photosynthesis at local, regional, and global scales, howev...

Due to its close link to the photosynthetic process, sun-induced chlorophyll fluorescence (F) opens new possibilities to study dynamics of photosynthetic light reactions and to quantify CO2 assimilation rates. Although recent studies show that F is linearly related to gross primary production (GPP) on coarse spatial and temporal scales, it is argue...

Zusammenfassung: Die Erfassung von Vegetationsparametern in landwirtschaftlichen Be-ständen gewinnt zunehmend an Bedeutung. Mit Hilfe von Unmanned Aerial Vehicles (UAVs) können Kulturpflanzen mit einer hohen räumlichen und zeitlichen Auflösung phänotypisiert werden. In der vorliegenden Studie wird die Ährenanzahl von Gerste mit Hilfe eines Multi-ko...

Emerging strategies and technologies in agriculture, such as precision farming and phenotyping depend on detailed data on all stages of crop development. Unmanned aerial vehicles promise to deliver such time series as they allow very frequent measurements. In this study, we analyse a field trial with two barley cultivars and two contrasting sowing...

Sun‐induced fluorescence ( SIF ) in the far‐red region provides a new noninvasive measurement approach that has the potential to quantify dynamic changes in light‐use efficiency and gross primary production ( GPP ). However, the mechanistic link between GPP and SIF is not completely understood. We analyzed the structural and functional factors cont...

Over the last twenty years, significant technical advances turned photogrammetry into a relevant tool for the integrated analysis of biogeomorphic cross-scale interactions within vegetated fluvial corridors, which will largely contribute to the development and improvement of self-sustainable river restoration efforts. Here, we propose a cost-effect...

Remote Sensing of Sun-Induced Chlorophyll Fluorescence (SIF) is a research field of growing interest because it offers the potential to quantify actual photosynthesis and to monitor plant status. New satellite missions from the European Space Agency, such as the Earth Explorer 8 FLuorescence EXplorer (FLEX) mission-scheduled to launch in 2022 and a...

This paper describes a novel method to derive 3D hyperspectral information from lightweight snapshot cameras for unmanned aerial vehicles for vegetation monitoring. Snapshot cameras record an image cube with one spectral and two spatial dimensions with every exposure. First, we describe and apply methods to radiometrically characterize and calibrat...

This study presents the results of methodological tests in aerial photogrammetry with the objective of a diachronic survey of riparian vegetation in three dimensions, i.e. its spatial distribution and height. The study is undertaken at two complementary scales. The first one corresponds to a 10 km reach of the Allier river floodplain. At this scale...

Measurements of sun-induced chlorophyll fluorescence (SIF) over plant canopies provide a proxy for plant photosynthetic capacity and are of high interest for plant research. Together with spectral reflectance, SIF has the potential to act as a noninvasive approach to quantify photosynthetic plant traits from field to air and spaceborne scales. Howe...

Variations in photosynthesis still cause substantial uncertainties in predicting photosynthetic CO2 uptake rates and monitoring plant stress. Changes in actual photosynthesis that are not related to greenness of vegetation are difficult to measure by reflectance based optical remote sensing techniques. Several activities are underway to evaluate th...

This study presents the results of methodological tests in aerial photogrammetry with the objective of a diachronic survey of riparian vegetation in three dimensions, i.e. its spatial distribution and height. The study is undertaken at two complementary scales.

Remote estimation of sun-induced chlorophyll fluorescence emitted by terrestrial vegetation can provide an unparalleled opportunity to track spatio-temporal variations of photosynthetic efficiency. Here we provide the first direct experimental evidence that the two peaks of the chlorophyll fluorescence spectrum can be accurately mapped from high-re...

In this study we present a hyperspectral flying goniometer system, based on a rotary-wing unmanned aerial vehicle (UAV) equipped with a spectrometer mounted on an active gimbal. We show that this approach may be used to collect multiangular hyperspectral data over vegetated environments. The pointing and positioning accuracy are assessed using stru...

Unmanned aerial vehicles (UAVs) equipped with lightweight spectral sensors facilitate non-destructive, near-real-time vegetation analysis. In order to guarantee robust scientific analysis, data acquisition protocols and processing methodologies need to be developed and new sensors must be compared with state-of-the-art instruments. Four different t...

The REFLEX 2012 campaign was initiated as part of a training course on the organization of an airborne campaign to support advancement of the understanding of land-atmosphere interaction processes. This article describes the campaign, its objectives and observations, remote as well as in situ. The observations took place at the experimental Las Tie...

In dieser Studie demonstrieren wir, wie man mit einfachen Mitteln, durch Visualisierung der Chlorophyllfluoreszenz, Einblicke in die Dynamik der Photosynthese erhält. Mithilfe eines Rotfilters und einer speziellen blauen Lampe wird das rote Leuchten der Chlorophyllfluoreszenz für das Auge oder eine normale Digitalkamera wahrnehmbar. Die Methode gib...

Unmanned Aerial Vehicles (UAVs) equipped with lightweight spectral sensors facilitate non-destructive, near real time vegetation analysis. In order to guarantee quality scientific analysis, data acquisition protocols and processing methodologies need to be developed and new sensors must be trialed against state of the art instruments. In the follow...

A novel hyperspectral measurement system for unmanned aerial vehicles (UAVs) in the visible to near infrared (VIS/NIR) range (350-800 nm) was developed based on the Ocean Optics STS microspectrometer. The ultralight device relies on small open source electronics and weighs a ready-to-fly 216 g. The airborne spectrometer is wirelessly synchronized t...

The two widespread tropical Solanum species S. paniculatum and S. stramoniifolium are highly dependent on the visits of large bees that pollinate the flowers while buzzing them. Both Solanum species do not offer nectar reward; the rewarding of bees is thus solely dependent on the availability of pollen. Flower visitors are unable to visually assess...

Lunau K, Piorek V, Konzmann S, Goertz A, Burkart A (2012) Why do bumblebees confuse pollen and pollen surrogates and collect glass powder? [Warum verwechseln Hummeln Pollen und Pollensurrogate und sammeln Glaspulver?] Abstractband der 59. Jahrestagung vom 27.03.-29.03.2012 der Arbeitsgemeinschaft der Institute für Bienenforschung e.V.; p 21. Why d...

The presence of bees is typically accompanied by the humming sound of their flight. Bees of several tribes are also capable of pollen collecting by vibration, known as buzzing behaviour, which produces a buzzing sound, different from the flight sound. An open question is whether bee species have species-specific buzzing patterns or frequencies depe...