Red edge Research Papers - Academia.edu (original) (raw)

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- Aerial Archaeology, Near Infrared, Aerial Archeology, Red edge

Remote sensing is a suitable candidate for monitoring rapid changes in Polar regions, offering high-resolution spectral, spatial and radiometric data. This paper focuses on the spectral properties of dominant plant species acquired during the first week of August 2015. Twenty-eight plots were selected, which could easily be identified in the field as well as on RapidEye satellite imagery. Spectral measurements of individual species were acquired, and heavy metal contamination stress factors were measured contemporaneously. As a result, a unique spectral library of dominant plant species, heavy metal concentrations and damage ratios were achieved with an indication that species-specific changes due to environmental conditions can best be differentiated in the 1401–2400 nm spectral region. Two key arctic tundra species, Cassiope tetragona and Dryas octopetala, exhibited significant differences in this spectral region that were linked to a changing health status. Relationships between field and satellite measurements were comparable, e.g., the Red Edge Normalized Difference Vegetation Index (RENDVI) showed a strong and significant relationship (R 2 = 0.82; p = 0.036) for the species Dryas octopetala. Cadmium and Lead were below detection levels while manganese, copper and zinc acquired near Longyearbyen were at concentrations comparable to other places in Svalbard. There were high levels of nickel near Longyearbyen (0.014 mg/g), while it was low (0.004 mg/g) elsewhere.

- by Bogdan Zagajewski and +4
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- Vegetation Ecology, Hyperspectral remote sensing, Arctic Climate, Svalbard

Imaging spectroscopy acquires imagery in hundreds or more narrow contiguous spectral bands. This offers unprecedented information for archaeological research. To extract the maximum of useful archaeological information from it, however, a number of problems have to be solved. Major problems relate to data redundancy and the visualization of the large amount of data. This makes data mining approaches necessary, as well as efficient data visualization tools. Additional problems relate to data quality. Indeed, the upwelling electromagnetic radiation is recorded in small spectral bands that are only about ten nanometers wide. The signal received by the sensor is, thus quite low compared to sensor noise and possible atmospheric perturbations. The often small, instantaneous field of view (IFOV)—essential for archaeologically relevant imaging spectrometer datasets—further limits the useful signal stemming from the ground. The combination of both effects makes radiometric smoothing techniques mandatory. The present study details the functionality of a MATLAB®-based toolbox, called ARCTIS (ARChaeological Toolbox for Imaging Spectroscopy), for filtering, enhancing, analyzing, and visualizing imaging spectrometer datasets. The toolbox addresses the above-mentioned problems. Its Graphical User Interface (GUI) is designed to allow non-experts in remote sensing to extract a wealth of information from imaging spectroscopy for archaeological research. ARCTIS will be released under creative commons license, free of charge, via website (http://luftbildarchiv.univie.ac.at).

- by Geert J Verhoeven and +1
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- Remote Sensing, Aerial Archaeology, Hyperspectral remote sensing, Archaeological Prospection

Remote sensing is a suitable candidate for monitoring rapid changes in Polar regions, offering high-resolution spectral, spatial and radiometric data. This paper focuses on the spectral properties of dominant plant species acquired during the first week of August 2015. Twenty-eight plots were selected, which could easily be identified in the field as well as on RapidEye satellite imagery. Spectral measurements of individual species were acquired, and heavy metal contamination stress factors were measured contemporaneously. As a result, a unique spectral library of dominant plant species, heavy metal concentrations and damage ratios were achieved with an indication that species-specific changes due to environmental conditions can best be differentiated in the 1401-2400 nm spectral region. Two key arctic tundra species, Cassiope tetragona and Dryas octopetala, exhibited significant differences in this spectral region that were linked to a changing health status. Relationships between field and satellite measurements were comparable, e.g., the Red Edge Normalized Difference Vegetation Index (RENDVI) showed a strong and significant relationship (R 2 = 0.82; p = 0.036) for the species Dryas octopetala. Cadmium and Lead were below detection levels while manganese, copper and zinc acquired near Longyearbyen were at concentrations comparable to other places in Svalbard. There were high levels of nickel near Longyearbyen (0.014 mg/g), while it was low (0.004 mg/g) elsewhere.

- by Bogdan Zagajewski
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- Environmental Science, Computer Science, Remote Sensing, Vegetation Ecology

Scientists from different research disciplines have provided essential information that relates the biophysical characteristics of plants to their spectral reflectance. This fundamental understanding has facilitated the development of various non-destructive sensing methods for detecting vegetation stresses, monitoring plant growth and calculating crop yield. Aerial archaeologists flying in small aeroplanes have only partially exploited this knowledge. Instead of basing archaeological interpretation on only direct visual inspection of the conventionally acquired colour photographs, this contribution briefly reviews the reflectance properties of plants and uses them to present a new low-cost imaging technique beneficial for the detection of (faint) archaeologically induced vegetation marks. The new approach consists of three simultaneously operated digital still cameras, each of them capturing information in a different spectral waveband: the visible, near-infrared and red-edge spectral region. The latter two bands are used in the calculation of a R700/R800 vegetation index. Besides a theoretical underpinning, real-world examples will assess the potential of this new approach in detection of vegetation marks and prove that this low-cost, multispectral method might be beneficial in identifying and enhancing weak crop stresses that are lost when taking only the broad visible spectrum into account. In the final discussion, some thoughts on future archaeological aerial research are given. Copyright © 2011 John Wiley & Sons, Ltd.

- by Michael Doneus
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- Aerial Archaeology, Red edge, Vegetation Index

- by Geert J Verhoeven and +1
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- Remote Sensing, Aerial Archaeology, Archaeological Prospection, Crop mark

Airborne hyperspectral scanning involves the mapping of a scene's wavelength intensity, accomplished by measuring upwelling electromagnetic radiation (reflected and/or emitted) in a multitude of contiguous narrow spectral bands. The end product consists of spatially co-registered two-dimensional images, each of them representing a spectral band that is typically just about ten nanometres wide. In this sense, imaging spectroscopy yields a three-dimensional data cube (x, y, λ ) in which the first two are the spatial dimensions, whereas the third axis contains a spectral dimension: a digital number (DN) that represents the sampled and quantized at-sensor radiance L for that particular waveband. In post-processing, reflectance (or emissive characteristics) can be calculated from these DNs. Through a combination of all spectral data acquired from a particular spatial location, every individual pixel of the final image holds the complete reflectance or emission spectrum (known as spectral signature) of the material that was sampled at that specific location. Since this spectral signature can be obtained for every pixel in the image, the technique is also called airborne imaging spectroscopy (AIS).

- by Anna Gakamsky
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- Mass Spectrometry, Fluorescence, Cataract, Tryptophan

Airborne remote sensing for archaeology is the discipline that encompasses the study of archaeological remains using data collected from an airborne platform by means of digital or film-based aerial photography, airborne laser scanning, hyperspectral imaging etc. So far, airborne hyperspectral scanning or – more accurately – airborne imaging spectroscopy (AIS) has occupied only a very small niche in the field of archaeological remote sensing: besides reasons of cost, the common archaeologically-insufficient ground-sampling distance can be considered the main limiting factor. Moreover, the technical processing of these data sets with a high level of potential redundancy needs specialized software. Typically, calculation of band ratios and a principal component analysis are applied. As a result, the few practical applications of archaeological AIS have not been entirely convincing so far. The aim of this paper is to present new approaches for analysing archaeological AIS data. The imagery under study has a ground-sampling distance of 40 cm and covers the Roman town of Carnuntum (Austria). Using two algorithms embedded in a specifically developed MATLAB® toolbox, it will be shown how the extracted archaeological information can be enhanced from high-resolution hyperspectral images. A comparison with simultaneously acquired vertical photographs will indicate the specific advantages of high-resolution AIS data and the gain one can obtain when exploiting its potential using any of the newly presented methods.

- by Geert J Verhoeven and +1
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- Archaeology, Remote Sensing, Aerial Archaeology, Hyperspectral remote sensing

The chemical nature of the non-tryptophan (non-Trp) fluorescence of porcine and human eye lens proteins was identified by Mass Spectrometry (MS) and Fluorescence Steady-State and Lifetime spectroscopy as post-translational modifications (PTM) of Trp and Arg amino acid residues. Fluorescence intensity profiles measured along the optical axis of human eye lenses with age-related nuclear cataract showed increasing concentration of fluorescent PTM towards the lens centre in accord with the increased optical density in the lens nucleolus. Significant differences between fluorescence lifetimes of “free” Trp derivatives hydroxytryptophan (OH-Trp), N-formylkynurenine (NFK), kynurenine (Kyn), hydroxykynurenine (OH-Kyn) and their residues were observed. Notably, the lifetime constants of these residues in a model peptide were considerably greater than those of their “free” counterparts. Fluorescence of Trp, its derivatives and argpyrimidine (ArgP) can be excited at the red edge of the Trp absorption band which allows normalisation of the emission spectra of these PTMs to the fluorescence intensity of Trp, to determine semi-quantitatively their concentration. We show that the cumulative fraction of OH-Trp, NFK and ArgP emission dominates the total fluorescence spectrum in both emulsified post-surgical human cataract protein samples, as well as in whole lenses and that this correlates strongly with cataract grade and age.

- by Dmitry Gakamsky and +3
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- Medical Diagnostic System, Red edge, Tryptophan fluorescence, Post translational modification of proteins
- by Anna Gakamsky
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- Mass Spectrometry, Fluorescence, Cataract, Tryptophan