On the reproducibility of field-measured reflectance factors in the context of vegetation studies

Anderson, Karen; Dungan, Jennifer; MacArthur, Alasdair

doi:10.1016/j.rse.2011.03.012

Cited by 27 publications

(30 citation statements)

References 39 publications

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“…We encourage manufacturers to build integrated dual spectrometer systems that provide accurate recordings in the dynamic conditions that are met in UAV remote sensing; challenges include rapid illumination changes, platform vibrations and movement, temperature effects, and others. For more information on the cross-calibration and reflectance factors retrieved with radiometric reference panels and multiple spectrometers, the interested reader is referred to the works of Anderson et al [3,151,199,200]. Further challenges that remain unresolved with the dual spectrometer systems include the disturbances caused by the object reflectance anisotropy and shadows captured in a measurement (e.g., part of an image) but not by the irradiance sensor and object topography.…”

Section: Radiometric Processingmentioning

confidence: 99%

Quantitative Remote Sensing at Ultra-High Resolution with UAV Spectroscopy: A Review of Sensor Technology, Measurement Procedures, and Data Correction Workflows

et al. 2018

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In the last 10 years, development in robotics, computer vision, and sensor technology has provided new spectral remote sensing tools to capture unprecedented ultra-high spatial and high spectral resolution with unmanned aerial vehicles (UAVs). This development has led to a revolution in geospatial data collection in which not only few specialist data providers collect and deliver remotely sensed data, but a whole diverse community is potentially able to gather geospatial data that fit their needs. However, the diversification of sensing systems and user applications challenges the common application of good practice procedures that ensure the quality of the data. This challenge can only be met by establishing and communicating common procedures that have had demonstrated success in scientific experiments and operational demonstrations. In this review, we evaluate the state-of-the-art methods in UAV spectral remote sensing and discuss sensor technology, measurement procedures, geometric processing, and radiometric calibration based on the literature and more than a decade of experimentation. We follow the 'journey' of the reflected energy from the particle in the environment to its representation as a pixel in a 2D or 2.5D map, or 3D spectral point cloud. Additionally, we reflect on the current revolution in remote sensing, and identify trends, potential opportunities, and limitations.

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Section: Radiometric Processingmentioning

confidence: 99%

Quantitative Remote Sensing at Ultra-High Resolution with UAV Spectroscopy: A Review of Sensor Technology, Measurement Procedures, and Data Correction Workflows

et al. 2018

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“…Information on what to purchase, how to install, maintain, calibrate, analyse, and store the data from in situ spectral measurements is to some extent available from a number of studies conducted as part of EUROSPEC or by other groups (see e.g. Anderson et al, 2011;Balzarolo et al, 2011;Gamon et al, 2015;Harris et al, 2014;Jin and Eklundh, 2015). These types of studies will most likely continue to appear in the near future.…”

Section: Future Challenges and Opportunitiesmentioning

confidence: 99%

“…Measurement uncertainty is instrument-and environment-specific. Accordingly, characterization of sensor performance and quantification of measurement uncertainty is crucial to producing accurate data (Anderson et al, 2011;Castro-Esau et al, 2006;Jung et al, 2012). Anderson et al (2011) have demonstrated that laboratoryderived measurement uncertainties do not present a useful means of quantifying all uncertainties in field spectroscopy.…”

Section: Future Challenges and Opportunitiesmentioning

confidence: 99%

“…Accordingly, characterization of sensor performance and quantification of measurement uncertainty is crucial to producing accurate data (Anderson et al, 2011;Castro-Esau et al, 2006;Jung et al, 2012). Anderson et al (2011) have demonstrated that laboratoryderived measurement uncertainties do not present a useful means of quantifying all uncertainties in field spectroscopy. Laboratory measurements can serve to define features such as signal-to-noise ratio, noise equivalent radiance and linearity, but these uncertainties are added to by complexities of the hemispherical illumination environment experienced in the field.…”

Section: Future Challenges and Opportunitiesmentioning

confidence: 99%

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EUROSPEC: at the interface between remote-sensing and ecosystem CO<sub>2</sub> flux measurements in Europe

Porcar‐Castell

Arthur²,

Rossini

et al. 2015

Biogeosciences

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Abstract.Resolving the spatial and temporal dynamics of gross primary productivity (GPP) of terrestrial ecosystems across different scales remains a challenge. Remote sensing is regarded as the solution to upscale point observations conducted at the ecosystem level, using the eddy covariance (EC) technique, to the landscape and global levels. In addition to traditional vegetation indices, the photochemical reflectance index (PRI) and the emission of solarinduced chlorophyll fluorescence (SIF), now measurable from space, provide a new range of opportunities to monitor the global carbon cycle using remote sensing. However, the scale mismatch between EC observations and the much coarser satellite-derived data complicate the integration of the two sources of data. The solution is to establish a network of in situ spectral measurements that can act as a bridge between EC measurements and remote-sensing data. In situ spectral measurements have already been conducted for many years at EC sites, but using variable instrumentation, setups, and measurement standards. In Europe in particular, in situ spectral measurements remain highly heterogeneous. The goal of EUROSPEC Cost Action ES0930 was to promote the development of common measuring protocols and new instruments towards establishing best practices and standardization of these measurements. In this review we describe the background and main tradeoffs of in situ spectral measurements, review the main results of EUROSPEC Cost Action, and discuss the future challenges and opportunities Published by Copernicus Publications on behalf of the European Geosciences Union. 6104A. Porcar-Castell et al.: Linking remote-sensing and flux measurements of in situ spectral measurements for improved estimation of local and global estimates of GPP over terrestrial ecosystems.

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“…However, different instrument designs, field measurement methods and inherent uncertainties need to be considered when developing field sampling strategies to further improve the utility of field spectroscopy. The uncertainties associated with field spectral measurements are now more widely recognised [10]. However, it is worth emphasising that field spectroscopy is normally a passive remote sensing method relying on the highly dynamic and ever changing skylight, as can be seen from Figure 1a, as the source of illumination.…”

Section: Introductionmentioning

confidence: 99%

A critique of field spectroscopy and the challenges and opportunities it presents for remote sensing for agriculture, ecosystems, and hydrology

Arthur

Robinson

2015

SPIE Proceedings

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From the early scanning spectrometers, the utility field spectroscopy has been constrained: by detector sensitivity, leading to high integration times; portability; and the measurements having very limited support (possibly an Earth surface area in the order of 0.25m 2 to 2m 2). However, over the last twenty years or so detector sensitivities and electronics have in improved leading to practical Earth surface sampling time increasing their utility to support Earth observation science and as optical remote sensing teaching and training tools. Now the uncertainties associated with field spectral measurements are being more widely recognised and field sampling methods and instrument continue to be developed to enable these uncertainties to be quantified and minimised. There are a number of key challenges which still need to be more widely addressed if field spectroscopy is to provide evermore reliable and replicable measurements. An understanding of the systematic biases introduced by this sampling method has begun to be recognised. In addition, the mismatch in scale between near-ground spectroscopy measurement and observations from space-borne sensor has begun to be addressed with the development of unmanned aerial vehicles as platforms and lightweight and miniaturised stateof-the-art spectrometer systems. It is now possible to non-invasively sample terrestrial and hydrological ecosystems in a statistically robust manner and do so with supports similar in scale to those of air-and space-borne sensors. These developments will revolutionise the use of field spectroscopy to support empirical science and model development and the calibration and validation of space-based observations.

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On the reproducibility of field-measured reflectance factors in the context of vegetation studies

Cited by 27 publications

References 39 publications

Quantitative Remote Sensing at Ultra-High Resolution with UAV Spectroscopy: A Review of Sensor Technology, Measurement Procedures, and Data Correction Workflows

Quantitative Remote Sensing at Ultra-High Resolution with UAV Spectroscopy: A Review of Sensor Technology, Measurement Procedures, and Data Correction Workflows

EUROSPEC: at the interface between remote-sensing and ecosystem CO<sub>2</sub> flux measurements in Europe

A critique of field spectroscopy and the challenges and opportunities it presents for remote sensing for agriculture, ecosystems, and hydrology

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On the reproducibility of field-measured reflectance factors in the context of vegetation studies

Cited by 27 publications

References 39 publications

Quantitative Remote Sensing at Ultra-High Resolution with UAV Spectroscopy: A Review of Sensor Technology, Measurement Procedures, and Data Correction Workflows

Quantitative Remote Sensing at Ultra-High Resolution with UAV Spectroscopy: A Review of Sensor Technology, Measurement Procedures, and Data Correction Workflows

EUROSPEC: at the interface between remote-sensing and ecosystem CO&lt;sub&gt;2&lt;/sub&gt; flux measurements in Europe

A critique of field spectroscopy and the challenges and opportunities it presents for remote sensing for agriculture, ecosystems, and hydrology

Contact Info

Product

Resources

About

EUROSPEC: at the interface between remote-sensing and ecosystem CO<sub>2</sub> flux measurements in Europe