537 research outputs found
Proceedings of the Second Airborne Imaging Spectrometer Data Analysis Workshop
Topics addressed include: calibration, the atmosphere, data problems and techniques, geological research, and botanical and geobotanical research
Proceedings of the Airborne Imaging Spectrometer Data Analysis Workshop
The Airborne Imaging Spectrometer (AIS) Data Analysis Workshop was held at the Jet Propulsion Laboratory on April 8 to 10, 1985. It was attended by 92 people who heard reports on 30 investigations currently under way using AIS data that have been collected over the past two years. Written summaries of 27 of the presentations are in these Proceedings. Many of the results presented at the Workshop are preliminary because most investigators have been working with this fundamentally new type of data for only a relatively short time. Nevertheless, several conclusions can be drawn from the Workshop presentations concerning the value of imaging spectrometry to Earth remote sensing. First, work with AIS has shown that direct identification of minerals through high spectral resolution imaging is a reality for a wide range of materials and geological settings. Second, there are strong indications that high spectral resolution remote sensing will enhance the ability to map vegetation species. There are also good indications that imaging spectrometry will be useful for biochemical studies of vegetation. Finally, there are a number of new data analysis techniques under development which should lead to more efficient and complete information extraction from imaging spectrometer data. The results of the Workshop indicate that as experience is gained with this new class of data, and as new analysis methodologies are developed and applied, the value of imaging spectrometry should increase
Assessment of the CORONA series of satellite imagery for landscape archaeology: a case study from the Orontes valley, Syria
In 1995, a large database of satellite imagery with worldwide coverage taken from 1960 until 1972 was declassified. The main advantages of this imagery known as
CORONA that made it attractive for archaeology were its moderate cost and its historical value. The main disadvantages were its unknown quality, format, geometry
and the limited base of known applications.
This thesis has sought to explore the properties and potential of CORONA imagery and thus enhance its value for applications in landscape archaeology. In order to ground these investigations in a real dataset, the properties and characteristics of CORONA imagery were explored through the case study of a landscape archaeology project working in the Orontes Valley, Syria. Present-day high-resolution IKONOS imagery was integrated within the study and assessed alongside CORONA imagery. The combination of these two image datasets was shown to provide a powerful set of tools for investigating past archaeological landscape in the Middle East.
The imagery was assessed qualitatively through photointerpretation for its ability to detect archaeological remains, and quantitatively through the extraction of height information after the creation of stereomodels. The imagery was also assessed spectrally
through fieldwork and spectroradiometric analysis, and for its Multiple View Angle (MVA) capability through visual and statistical analysis.
Landscape archaeology requires a variety of data to be gathered from a large area, in an effective and inexpensive way. This study demonstrates an effective methodology for the deployment of CORONA and IKONOS imagery and raises a number of technical points of which the archaeological researcher community need to be aware of. Simultaneously, it identified certain limitations of the data and suggested solutions for the more effective exploitation of the strengths of CORONA imagery
APERO: A PipelinE to Reduce Observations -- Demonstration with SPIRou
With the maturation of near-infrared high-resolution spectroscopy, especially
when used for precision radial velocity, data reduction has faced unprecedented
challenges in terms of how one goes from raw data to calibrated, extracted, and
corrected data with required precisions of thousandths of a pixel. Here we
present APERO (A PipelinE to Reduce Observations), specifically focused on
SPIRou, the near-infrared spectropolarimeter on the Canada--France--Hawaii
Telescope (SPectropolarim\`etre InfraROUge, CFHT). In this paper, we give an
overview of APERO and detail the reduction procedure for SPIRou. APERO delivers
telluric-corrected 2D and 1D spectra as well as polarimetry products. APERO
enables precise stable radial velocity measurements on sky (via the LBL
algorithm), good to at least ~2 m/s over the current 5-year lifetime of SPIRou.Comment: Accepted for publication in PASP. 55 pages, 29 figures, 10 pages of
Appendice
The MUSE-Wide Survey: Survey Description and First Data Release
We present the MUSE-Wide survey, a blind, 3D spectroscopic survey in the
CANDELS/GOODS-S and CANDELS/COSMOS regions. Each MUSE-Wide pointing has a depth
of 1 hour and hence targets more extreme and more luminous objects over 10
times the area of the MUSE-Deep fields (Bacon et al. 2017). The legacy value of
MUSE-Wide lies in providing "spectroscopy of everything" without photometric
pre-selection. We describe the data reduction, post-processing and PSF
characterization of the first 44 CANDELS/GOODS-S MUSE-Wide pointings released
with this publication. Using a 3D matched filtering approach we detected 1,602
emission line sources, including 479 Lyman- (Lya) emitting galaxies
with redshifts . We cross-match the emission line
sources to existing photometric catalogs, finding almost complete agreement in
redshifts and stellar masses for our low redshift (z < 1.5) emitters. At high
redshift, we only find ~55% matches to photometric catalogs. We encounter a
higher outlier rate and a systematic offset of z0.2 when
comparing our MUSE redshifts with photometric redshifts. Cross-matching the
emission line sources with X-ray catalogs from the Chandra Deep Field South, we
find 127 matches, including 10 objects with no prior spectroscopic
identification. Stacking X-ray images centered on our Lya emitters yielded no
signal; the Lya population is not dominated by even low luminosity AGN. A total
of 9,205 photometrically selected objects from the CANDELS survey lie in the
MUSE-Wide footprint, which we provide optimally extracted 1D spectra of. We are
able to determine the spectroscopic redshift of 98% of 772 photometrically
selected galaxies brighter than 24th F775W magnitude. All the data in the first
data release - datacubes, catalogs, extracted spectra, maps - are available on
the website https://musewide.aip.de. [abridged]Comment: 25 pages 15+1 figures. Accepted, A&A. Comments welcom
The Initial Conditions of Clustered Star Formation. II. N2H+ Observations of the Ophiuchus B Core
We present a Nobeyama 45 m Radio Telescope map and Australia Telescope
Compact Array pointed observations of N2H+ 1-0 emission towards the clustered,
low mass star forming Oph B Core within the Ophiuchus molecular cloud. We
compare these data with previously published results of high resolution NH3
(1,1) and (2,2) observations in Oph B. We use 3D Clumpfind to identify emission
features in the single-dish N2H+ map, and find that the N2H+ `clumps' match
well similar features previously identified in NH3 (1,1) emission, but are
frequently offset to clumps identified at similar resolution in 850 micron
continuum emission. Wide line widths in the Oph B2 sub-Core indicate
non-thermal motions dominate the Core kinematics, and remain transonic at
densities n ~ 3 x 10^5 cm^-3 with large scatter and no trend with N(H2).
Non-thermal motions in Oph B1 and B3 are subsonic with little variation, but
also show no trend with H2 column density. Over all Oph B, non-thermal N2H+
line widths are substantially narrower than those traced by NH3, making it
unlikely NH3 and N2H+ trace the same material, but the v_LSR of both species
agree well. We find evidence for accretion in Oph B1 from the surrounding
ambient gas. The NH3/N2H+ abundance ratio is larger towards starless Oph B1
than towards protostellar Oph B2, similar to recent observational results in
other star-forming regions. Small-scale structure is found in the ATCA N2H+ 1-0
emission, where emission peaks are again offset from continuum emission. In
particular, the ~1 M_Sun B2-MM8 clump is associated with a N2H+ emission
minimum and surrounded by a broken ring-like N2H+ emission structure,
suggestive of N2H+ depletion. We find a strong general trend of decreasing N2H+
abundance with increasing N(H2) in Oph B which matches that found for NH3.Comment: 55 pages (manuscript), 15 figures, ApJ accepte
Exploring Himawari-8 geostationary observations for the advanced coastal monitoring of the Great Barrier Reef
Larissa developed an algorithm to enable water-quality assessment within the Great Barrier Reef (GBR) using weather satellite observations collected every 10 minutes. This unprecedented temporal resolution records the dynamic nature of water quality fluctuations for the entire GBR, with applications for improved monitoring and management
Extrinsic Auto-calibration of a Camera and Laser Range Finder
This paper describes theoretical and experimental results for the auto-calibration of sensor platform consisting of a camera and a laser range finder. Real-world use of autonomous sensor platforms often requires the recalibration of sensors without an explicit calibration object. The constraints are based upon data captured simultaneously from the camera and the laser range finder while the sensor plat-form undergoes an arbitrary motion. The rigid motions of both sensors are related, so these data constrain the relative position and orientation of the camera and laser range finder. We introduce the mathematical constraints for auto-calibration techniques based upon both discrete and differential motions, and present simulated experimental results, and results from a implementation on a B21rT M Mobile Robot from iRobot Corporation. This framework could also encompass extrinsic calibration with GPS, inertial, infrared, and ultrasonic sensors
Synthetic aperture radar/LANDSAT MSS image registration
Algorithms and procedures necessary to merge aircraft synthetic aperture radar (SAR) and LANDSAT multispectral scanner (MSS) imagery were determined. The design of a SAR/LANDSAT data merging system was developed. Aircraft SAR images were registered to the corresponding LANDSAT MSS scenes and were the subject of experimental investigations. Results indicate that the registration of SAR imagery with LANDSAT MSS imagery is feasible from a technical viewpoint, and useful from an information-content viewpoint
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