Search results for "Image resolution"
showing 10 items of 377 documents
The SMAP and Copernicus Sentinel 1A/B microwave active-passive high resolution surface soil moisture product
2019
Abstract Soil Moisture Active Passive (SMAP) mission of NASA was launched in January 2015. Currently, SMAP has an L-band radiometer and a defunct L-band radar with a rotating 6-m mesh reflector antenna. On July 7th, 2015, the SMAP radar malfunctioned and became inoperable. Consequently, the production of high-resolution active-passive soil moisture product got hampered, and only ~2.5 months (April 15th, 2015 to July 7th, 2015) of data remain available. Therefore, during the SMAP post-radar phase, many ways were examined to restart the high-resolution soil moisture product generation of the SMAP mission. One of the feasible approaches was to substitute the SMAP radar with other available SAR…
The effects of precipitates on CdZnTe device performance
2005
A high-intensity X-ray beam collimated down to a 10-micrometer spot size, available at Brookhaven's National Synchrotron Light Source (NSLS), was employed to perform X-ray mapping to measure the correlation between microscopic defects (precipitates) and variations in the collected charges in long-drift CdZnTe (CZT) detectors. First, we use X-ray diffraction topography (XDT) measurements at the high-energy beamline and IR microscopy to identify the defects distribution and strains in the bulk of CZT crystals. Then, we perform X-ray raster scans of the CZT detectors to measure their responses with 10-micrometer spatial resolution. The brightness of the source allows for good statistics in ver…
Affine compensation of illumination in hyperspectral remote sensing images
2009
A problem when working with optical satellite or airborne images is the need to compensate for changes in the illumination conditions at the time of acquisition. This is particularly critical when working with time series of data. Atmospheric correction strategies based on radiative transfer codes may provide a rigorous solution but it may not be the best solution for situations where a huge amount of hyperspectral images may need to be processed and computational time is a critical factor. The GMES (”Global Monitoring for Environment and Security”) initiative has promoted the creation of a new generation of satellites (the SENTINEL series) with ”ultra-high resolution” and ”superspectral im…
Ein Auswerteprogramm zur quantitativen Untersuchung der Lungenventilation mittels dynamischer MRT von hochpolarisiertem 3He
2004
Purpose: 3 He-MRI is able to visualize the regional distribution of lung ventilation with a temporal and spatial resolution so far unmatched by any other technique. The aim of the study was the development of a new software tool for quantification of dynamic ventilation parameters in absolute physical units. Materials and Methods: During continuous breathing, a bolus of hyperpolarized 3 He (300 ml) was applied at inspiration and a series of 168 coronal projection images simultaneously acquired using a 2D FLASH-sequence. Postprocessing software was developed to analyze the 3 He distribution in the lung. After correction for lung motion, several ventilation parameters (rise time, delay time, …
A Model to Characterize the D-T Layer of ICF Targets by Backlit Optical Shadowgraphy
2005
A numerical model is presented in order to modelize the bright ring that appears in backlit optical shadowgraphy on a transparent hollow sphere with a solid deuterium-tritium layer inside. This novel model is based on computational calculations applied to the problem of the targets used in inertial confinement fusion. The model takes into account the influences of the optical imaging system (numerical aperture, source divergence, camera resolution, etc.) and the effect of the capsule itself, diameter, thickness, and refractive index, and allows one to analyze the inner surface of a capsule in terms of thickness and roughness.
Precision Muon Reconstruction in Double Chooz
2014
We describe a muon track reconstruction algorithm for the reactor anti-neutrino experiment Double Chooz. The Double Chooz detector consists of two optically isolated volumes of liquid scintillator viewed by PMTs, and an Outer Veto above these made of crossed scintillator strips. Muons are reconstructed by their Outer Veto hit positions along with timing information from the other two detector volumes. All muons are fit under the hypothesis that they are through-going and ultrarelativistic. If the energy depositions suggest that the muon may have stopped, the reconstruction fits also for this hypothesis and chooses between the two via the relative goodness-of-fit. In the ideal case of a thro…
Radiation hard monolithic CMOS sensors with small electrodes for High Luminosity LHC
2019
Abstract The upgrade of the tracking detectors for the High Luminosity-LHC (HL-LHC) requires the development of novel radiation hard silicon sensors. The development of Depleted Monolithic Active Pixel Sensors targets the replacement of hybrid pixel detectors with radiation hard monolithic CMOS sensors. We designed, manufactured and tested radiation hard monolithic CMOS sensors in the TowerJazz 180 nm CMOS imaging technology with small electrodes pixel designs. These designs can achieve pixel pitches well below current hybrid pixel sensors (typically 50 × 50 μ m ) for improved spatial resolution. Monolithic sensors in our design allow to reduce multiple scattering by thinning to a total si…
Internal alignment and position resolution of the silicon tracker of DAMPE determined with orbit data
2017
Abstract The DArk Matter Particle Explorer (DAMPE) is a space-borne particle detector designed to probe electrons and gamma-rays in the few GeV to 10 TeV energy range, as well as cosmic-ray proton and nuclei components between 10 GeV and 100 TeV. The silicon–tungsten tracker–converter is a crucial component of DAMPE. It allows the direction of incoming photons converting into electron–positron pairs to be estimated, and the trajectory and charge (Z) of cosmic-ray particles to be identified. It consists of 768 silicon micro-strip sensors assembled in 6 double layers with a total active area of 6.6 m 2 . Silicon planes are interleaved with three layers of tungsten plates, resulting in about o…
Performance of prototypes for the ALICE electromagnetic calorimeter
2009
The performance of prototypes for the ALICE electromagnetic sampling calorimeter has been studied in test beam measurements at FNAL and CERN. A $4\times4$ array of final design modules showed an energy resolution of about 11% /$\sqrt{E(\mathrm{GeV})}$ $\oplus$ 1.7 % with a uniformity of the response to electrons of 1% and a good linearity in the energy range from 10 to 100 GeV. The electromagnetic shower position resolution was found to be described by 1.5 mm $\oplus$ 5.3 mm /$\sqrt{E \mathrm{(GeV)}}$. For an electron identification efficiency of 90% a hadron rejection factor of $>600$ was obtained.
High resolution detectors based on continuous crystals and SiPMs for small animal PET
2012
International audience; Sensitivity and spatial resolution are the two main factors to maximize in emission imaging. The improvement of one factor deteriorates the other with pixelated crystals. In this work we combine SiPM matrices with monolithic crystals, using an accurate γ-ray interaction position determination algorithm that provides depth of interaction. Continuous crystals provide higher sensitivity than pixelated crystals, while an accurate interaction position determination does not degrade the spatial resolution. Monte Carlo simulations and experimental data show good agreement both demonstrating sub-millimetre intrinsic spatial resolution. A system consisting in two rotating det…