Search results for "Geomatics"

2021

Abstract Terrestrial Essential Climate Variables, known as terrestrial ECVs, are key sources of information for both application- and scientific- oriented research. A large number of global terrestrial ECV products have been derived from satellite observations, and more are forthcoming. To unlock the full potential of these products, end-users need to know their uncertainties and error magnitudes. Due to the lack of conformity among validation strategies, a wide range of validation approaches have been employed to assess the quality of these products, and have resulted in reduced comparability even for the same terrestrial ECV. Addressing this challenge in validation practices requires the …

Test of the MODIS Land Surface Temperature and Emissivity Separation Algorithm With Ground Measurements Over a Rice Paddy

2016

The Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) and emissivity separation (MODTES) algorithm is the basis of the MOD21 product, which provides 1-km LSTs and emissivities for bands 29 (8.55 μm), 31 (11 μm), and 32 (12 μm). The MODTES algorithm uses the TES method with the water vapor scaling (WVS) method for refined atmospheric correction. The performance of the MODTES algorithm was tested with a set of MODIS data concurrent with ground LST and emissivity measurements. The test site is a large area of homogeneous full-cover rice crops (graybody), with high atmospheric water vapor. The data included LSTs measured along transects with multiple calibrate…

Atmospheric correction of optical imagery from MODIS and Reanalysis atmospheric products

2010

article i nfo In this paper we analyze the differences obtained in the atmospheric correction of optical imagery covering bands located in the Visible and Near Infra-Red (VNIR), Short-Wave Infra-Red (SWIR) and Themal-Infrared (TIR) spectral regions when atmospheric profiles extracted from different sources are used. In particular, three sensors were used, Compact High Resolution Imaging Spectrometer (CHRIS), Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) and Landsat5 Thematic Mapper (TM), whereas four atmospheric profiles sources were considered: i) local soundings launched near the sensor overpass time, ii) Moderate Resolution Radiometer (MODIS) atmospheric profiles…

The CoSMOS L-band experiment in Southeast Australia

2007

The CoSMOS (Campaign for validating the Operation of the Soil Moisture and Ocean Salinity mission) campaign was conducted during November of 2005 in the Goulburn River Catchment, in SE Australia. The main objective of CoSMOS was to obtain a series of L-band measurements from the air in order to validate the L-band emission model that will be used by the SMOS (Soil Moisture and Ocean Salinity) ground segment processor. In addition, the campaign was designed to investigate open questions including the Sun-glint effect over land, the application of polarimetric measurements over land, and to clarify the importance of dew and interception for soil moisture retrievals. This paper summarises the …

Shifting of wrapped phase maps in the frequency domain using a rational number

2016

The number of phase wraps in an image can be either reduced, or completely eliminated, by transforming the image into the frequency domain using a Fourier transform, and then shifting the spectrum towards the origin. After this, the spectrum is transformed back to the spatial domain using the inverse Fourier transform and finally the phase is extracted using the arctangent function. However, it is a common concern that the spectrum can be shifted only by an integer number, meaning that the phase wrap reduction is often not optimal. In this paper we propose an algorithm than enables the spectrum to be frequency shifted by a rational number. The principle of the proposed method is confirmed b…

Multidisciplinary approach to characterize archaeological materials and status of conservation of the Roman thermae of reggio Calabria Site (Calabria…

2020

This multidisciplinary research focuses on diagnostic investigations to characterize the archaeological materials, as well as the alteration and degradation forms detected at the Roman Thermae of Reggio Calabria (Calabria, South Italy) site. The thermal complex, (dating I–II century B.C.), was built around three main rooms such as the caldarium (hot bath), the tepidarium (warm bath) and the frigidarium (cold bath), all connected to a central room through several entrances. The central hall still preserves a suggestive mosaic floor dating between the II and III century A.D., characterized by geometric motifs and black and white tesserae. Fragments of various archaeological stone materials, s…

An automatic filtering algorithm for SURF-based registration of remote sensing images

2017

International audience; The registration of remote sensing images has been often a necessary step for further analyses of images taken at different times, different viewing geometry or with different sensors. For this task there exists many approaches. This paper focuses on the feature-based category of image registration methods. Particularly, we propose an improvement of the SURF algorithm on the point matching step. Indeed, in order to achieve a correct registration, a good matching of feature point is required. However The presence of outliers lead to a fail in the registration. Therefore, in this paper, we introduce an efficient method devoted to the detection and removal of such outli…

Kernel Spectral Angle Mapper

2016

This communication introduces a very simple generalization of the familiar spectral angle mapper (SAM) distance. SAM is perhaps the most widely used distance in chemometrics, hyperspectral imaging, and remote sensing applications. We show that a nonlinear version of SAM can be readily obtained by measuring the angle between pairs of vectors in a reproducing kernel Hilbert spaces. The kernel SAM generalizes the angle measure to higher-order statistics, it is a valid reproducing kernel, it is universal, and it has consistent geometrical properties that permit deriving a metric easily. We illustrate its performance in a target detection problem using very high resolution imagery. Excellent re…

From Waste to Resource – Utilising Residue from Ready-Made Concrete as New Aggregate

2021

Abstract A new admixture is available, to reduce the sludge produced from the cleansing of production and transportation equipment in the fresh concrete industry. The result is agglomerations of hardening concrete, that might be utilised for aggregate. Utilisation depends on adequate properties. This paper reports from investigations on the physical and mechanical properties of the aggregate and discussions on the performance relative to natural and recycled aggregates and towards requirements for utilisation. The findings indicate substantial potential for utilisation, supporting the reduction of waste for deposit and development of the concrete industry towards a circular economy.

Fluorescence estimation in the framework of the CEFLES2 campaign

2011

International audience; Chlorophyll fluorescence (ChF) is a relevant indicator of the actual plant physiological status. In this article different methods to measure ChF from remote sensing are evaluated: The Fraunhofer Line Discrimination (FLD), theFluorescence Radiative Method (FRM) and the improved Fraunhofer Line Discrimination (iFLD). The three methods have been applied to data acquired in the framework of the CarboEurope, FLEX and Sentinel-2 (CEFLES2) campaign in Les Landes, France in September 2007. Comparing with in situ measurements, the results indicate that the methods that provide the best results are the FLD and the iFLD with root mean square errors (RMSEs) of 0.4 and 0.5 mW m-…