Buried man-made structures, like archaeological handiworks, altering the natural trend of the soil surface can yield tonal
anomalies on remotely sensed images. These anomalies differ in size and/or intensity according to either the
environmental conditions at the time of acquisition or the spectral and spatial characteristics of the images. The research
challenge is to identify the best wavelength to detect these anomalies.
In this paper we have set up two new parameters for identifying and assessing the potential of anomaly detection: the
Detection Index (DI), which counts the pixels related to the marks, and the Separation Index (SI), which relates the
difference in brightness of the marks with respect to the background. These two indexes have been tested on MIVIS
(Multispectral Visible Imaging Spectrometer) airborne hyperspectral data acquired on remains not yet excavated of a few
archaeological sites. Results show that such indexes are an efficient, flexible and quick tool for assessing the image
potential to detect buried structures. Moreover, when they are applied to hyperspectral data, they allows for identifying
the spectral range more sensitive to the detection of the buried structures.
This work is aimed to atmospherically correct remote sensing data in the solar spectral domain (Visible and Near Infrared)
allowing the better assessment of the surface spectral material characteristics. This was obtained by the inversion of
the radiative transfer equation for at-sensor signal. In order to detect targets with peculiar spectral characteristics, the
atmospheric correction has to take into account the diffuse radiation that constitutes a significant component to the at
sensor radiance. The effect of this component (namely adjacency effect), which tends to mask the pixel seen by the sensor,
derives principally from the atmospheric scattering due to the aerosol loading in the scene. At this purpose an algorithm
based on 6S calculation was defined to derive the direct and diffuse component of the radiation required to determine the
contribution to the pixel reflectance related to the surrounding pixels. The developed algorithm allowed the assessment of
this environmental contribution besides the pixel reflectance. Such application, on airborne hyperspectral sensor MIVIS
(Multispectral Infrared and Visible Imaging Spectrometer) scenes, leads to obtain accurate pixel reflectance if compared
with ground measurements acquired within testing areas. This work shows how adjacency effect has a significant role in
the correction of remote sensing data, especially if acquired by an airborne hyperspectral sensor. The preliminary analysis
of the results have highlighted that the adjacency effect is not negligible, mainly when pixels in the scene are spectrally
heterogeneous.
The study, proposed within the framework of the cooperation with Kenyan Authorities, has been carried out on the
Kenyan part of the Lake Victoria. This lake is one of the largest freshwater bodies of the world where, over the last few
years, environmental challenges and human impact have perturbed the ecological balance. Pollution and sediments loads
from the tributaries rivers and antrophic sources caused a worrying increase of the turbidity level of the lake water.
Secchi transparency index has declined from 5 meters in the 1930s to less than one meter in the 1990s. With the aim of
providing an inexpensive way to gather information linked to the water clarity and quality, a method for remotely sensed
data interpretation, devoted to produce chl (chlorophyll), CDOM (coloured dissolved organic matter) and TSS (total
suspended solids) maps, has been assessed. At this purpose a bio-optical model, based on radiative transfer theory in
water bodies, has been refined. The method has been applied on an image acquired on January 2004 by
ENVISAT/MERIS sensor just a week after an in situ campaign took place. During the in situ campaign a data set for
model refinement and products validation has been collected. This data comprise surface radiometric quantity and
samples for laboratory analyses. The comparison between the obtained maps and the data provided by the laboratory
analysis showed a good correspondence, demonstrating the potentiality of remote observation in supporting the
management of the water resources.
The Straits of Messina was surveyed on September the 25th 1999, at 14:15 local time, by means of the 4 spectrometers of Multispectral Infrared Visible Imaging Spectrometer instrument, recording 102 channels from Visible to Thermal Infrared along four southwards oriented flight lines. The first flight line was recorded from an altitudes of 1500 m a.s.1. (nadir pixel size of 3 m), while the others have been acquired from an altitudes of 4000 m a.s.1. (nadir pixel size of 8 m). In the Straits of Messina the strong tidal currents as well as the morphological features determine the upwelling of deep waters to the photic layer. Traditional oceanographic surveys, based on period punctual sampling, are sometimes inadequate to deeply investigate the areas subjected to high variability altering in space and in time the distribution of abiotic and biotic parameters. The effect of tidal currents on the upwelling of the Straits of Messina was measured by using the MIVIS hyperspectral sensor and through the continuous survey of some tracer parameters from sailing vessel. The collected hyperspectral data sets, once calibrated to reflectance (by using atmospheric model and fields spectra collected during the campaign) and geometrically corrected, were used to develop preliminary local bio-optical algorithms derived from in situ (ground and sea) measurements and to obtain suitable mapping of the chlorophyll distribution and of the Sea Surface Temperature of the investigated area.
KEYWORDS: Image processing, 3D modeling, Scanners, Global Positioning System, Spectrometers, 3D image processing, Raster graphics, Software development, Data modeling, Sensors
Study to develop a software methodology to geocode MIVIS hyperspectral images collected by the CNR LARA Project. Goal of the study is to integrate the airborne position and attitude system with the image data to obtain geocoded images at a medium-small scale (1:15000 - 1:10000).
This presentation, taking its inspiration from various theoretical contributions suggested by various proposals, and going beyond the usual explanations and sometimes rash forecasts that the impact of a new technology has on physical space, wishes to underline the most important aspects of the introduction of a new method of studying urban installations, both ancient and modern, which is offered by urban telesurveys. To this end it is proposed, by means of an analysis of a sample area obtained from tele- surveying data provided by an aerial survey, using an advanced system of electronic pictures shot by MIVIS AA500000 of the CNR-Progetto LARA, to reveal and elaborate various findings and thus highlight a quantity and quality of extremely useful data.
The availability of MIVIS hyperspectral data, deriving from an aerial survey recently performed over a test-site in Lake Garda, Italy, gave the possibility of a preliminary new insight in the field of specific applications of remote sensing to shallow water analysis. The spectroradiometers in the visible and in the thermal infrared were explored in particular, accessing to helpful information for the detection of bio-physical indicators of water quality, either related to the surface/sub-surface of waters or to the bottom of the lake, since the study area presents very shallow waters, never exceeding a 6-meter depth in any case. Primary interest was the detection of man-induced activities along the margins, like sewage effect and sedimentary structure in the bottom or algal bloom. Secondly, a correlation between absorbivity coefficients in the visible bands and bathimetric contour lines in the proximity of the marginal zone of the lake was accomplished, by means of two indicative spectroradiometric transects.
On February 1994 a large area close to Trecate was affected by an oil blow-out from an AGIP rig located within the Ticino Regional Park. One month later an airborne survey has been carried out in the framework of the CNR Lara Project, by utilizing the Daedalus AA5000 MIVIS spectrometer with 102 channels from visible to thermal infrared. Different authors stress, for oil slicks discrimination, the utility of laser and microwaves based techniques, but the high spatial and spectral MIVIS resolutions can improve the detection of the relative coverage by spilled oil. This task has been performed by applying hyperspectral unmixing methods to the MIVIS calibrated data, obtaining an oil fractional image with respect to other chosen end-members. The analysis has shown a good agreement between the results of the unconstrained unmixing technique applied to MIVIS data and the ground truths, offering a tool useful to quantify in a synoptic overview the effects of oil spills over land, by relating the ppm of oil with the oil hyperspectral information gathered by MIVIS.
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