Search results for "Remote sensing"

Retrieval of chlorophyll content and LAI of crops using hyperspectral techniques: application to PROBA/CHRIS data

2008

Hyperspectral/multiangular data allow the retrieval of important vegetation properties at canopy level, such as the Leaf Area Index (LAI) and Leaf Chlorophyll Content. Current methods are based on the relationship between biophysical properties and retrievals from those spectral bands (from the complete hyperspectral/multiangular information) where specific absorption features are present within the considered spectral range. Furthermore, new sensors such as PROBA/CHRIS provide continuous hyperspectral reflectance measurements that can be considered as a continuous function of wavelength. The mathematical analysis of these continuous functions allows a new way of exploiting the relationship…

Optical remote sensor for alcohol concentration in blood

2012

In this paper we incorporate recently developed novel optical approach for extraction of remote vibration sources to estimate the alcohol concentration in blood stream.

Evaluation of remote sensing of vegetation fluorescence by the analysis of diurnal cycles

2008

Chlorophyll fluorescence (ChF) emission is a direct indicator of the photosynthetic activity of vegetation, which is a key parameter of the carbon cycle. This paper analyses chlorophyll fluorescence evolution at leaf level during a complete diurnal cycle in simulated and natural conditions, for two species under different stress conditions. Absolute spectral radiance of the ChF emission is obtained allowing a quantitative derivation of the fluorescence yield of the ChF, which correlates well with established fluorescence instruments. The studied cases show that the ChF emission is mainly driven by the photosynthetic active radiation during the whole cycle, but the fluorescence yield is seve…

Geostatistics for Mapping Leaf Area Index over a Cropland Landscape: Efficiency Sampling Assessment

2010

This paper evaluates the performance of spatial methods to estimate leaf area index (LAI) fields from ground-based measurements at high-spatial resolution over a cropland landscape. Three geostatistical model variants of the kriging technique, the ordinary kriging (OK), the collocated cokriging (CKC) and kriging with an external drift (KED) are used. The study focused on the influence of the spatial sampling protocol, auxiliary information, and spatial resolution in the estimates. The main advantage of these models lies in the possibility of considering the spatial dependence of the data and, in the case of the KED and CKC, the auxiliary information for each location used for prediction pur…

Monitoring water and carbon fluxes at fine spatial scales using HyspIRI-like measurements

2012

Remotely sensed observations in the visible to the shortwave infrared (VSWIR) and thermal infrared (TIR) regions of the electromagnetic spectrum can be used synergistically to provide valuable products of land surface properties for reliable assessments of carbon and water fluxes. The high spatial, spectral and temporal resolution VSWIR and TIR observations provided by the proposed Hyperspectral - InfraRed (HyspIRI) mission will enable a new era of global agricultural monitoring, critical for addressing growing issues of food insecurity. To enable predictions at fine spatial resolution (<100m), modeling efforts must rely on a combination of high-frequency temporal and highresolution spa…

Monitoring Water and Energy Cycles at Climate Scale in the Third Pole Environment (CLIMATE-TPE)

2021

A better understanding of the water and energy cycles at climate scale in the Third Pole Environment is essential for assessing and understanding the causes of changes in the cryosphere and hydrosphere in relation to changes of plateau atmosphere in the Asian monsoon system and for predicting the possible changes in water resources in South and East Asia. This paper reports the following results: (1) A platform of in situ observation stations is briefly described for quantifying the interactions in hydrosphere-pedosphere-atmosphere-cryosphere-biosphere over the Tibetan Plateau. (2) A multiyear in situ L-Band microwave radiometry of land surface processes is used to develop a new microwave r…

Digital zenith camera for vertical deflection determination

2012

Recent accomplishments in advancement of accurate astrometric reference star catalogues, development of digital imaging technology, high accuracy tiltmeter technology, and geocentric coordinate availability provided by GNSS, have made possible accurate, fast and automated determination of vertical deflections using astrometric methods. Zenith cameras for this kind of measurements have been developed or are being developed by several research groups. The paper describes a research project by Institute of Geodesy and Geoinformation, intended to design a portable digital zenith camera for vertical deflection determination with 0.1” expected accuracy. Camera components are described, proposed d…

Unmanned aerial vehicle application for mapping individual plants: the case of the Nebrodi beech forest

2015

The UAVs (Unmanned Aerial Vehicles) are small unmanned aircraft remote controlled electronically, commonly called "drones", which can serve as a vector to carry one or more sensors for georeferenced digital image capture. The development of these platforms is begun in the 50s for military purposes and is today successfully applied in the civil sphere with levels of technology and higher performance. It is a remote sensing technique to the scale of detail that allows for monitoring, measuring and mapping of several environmental data in a short time. The use of NDIR sensors (Non Dispersive Infrared sensor) for the detection of plant cover, allows discriminating plant species, mapping individ…

Dam displacements monitoring by using GNSS and remote sensing techniques

Il presente lavoro mira a valutare le potenzialità delle tecniche satellitari per il monitoraggio delle dighe. In particolare, l’attenzione è stata rivolta alle dighe di terra, poichè queste rappresentano la tipologia costruttiva più diffusa ed i modelli esistenti in letteratura sono in grado di descriverne gli spostamenti solo nell’ipotesi di conoscere accuratamente tutti parametri geotecnici e strutturali che caratterizzano la composizione della diga stessa. Negli ultimi anni, è stato ampiamente dimostrato che le tecniche satellitari da remoto sono in grado di individuare con elevata accuratezza, il comportamento di grandi strutture (incluse le dighe), valutandone spostamenti e deformazio…

Nonlinear Time-Series Adaptation for Land Cover Classification

2017

Automatic land cover classification from satellite image time series is of paramount relevance to assess vegetation and crop status, with important implications in agriculture, biofuels, and food. However, due to the high cost and human resources needed to characterize and classify land cover through field campaigns, a recurrent limiting factor is the lack of available labeled data. On top of this, the biophysical–geophysical variables exhibit particular temporal structures that need to be exploited. Land cover classification based on image time series is very complex because of the data manifold distortions through time. We propose the use of the kernel manifold alignment (KEMA) method for…