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Sample records for imager ground-based prototype

  1. Fresnel Interferometric Imager: ground-based prototype.

    PubMed

    Serre, Denis; Deba, Paul; Koechlin, Laurent

    2009-05-20

    The Fresnel Interferometric Imager is a space-based astronomical telescope project yielding milli-arcsecond angular resolution and high contrast images with loose manufacturing constraints. This optical concept involves diffractive focusing and formation flying: a first "primary optics" space module holds a large binary Fresnel array, and a second "focal module" holds optical elements and focal instruments that allow for chromatic dispersion correction. We have designed a reduced-size Fresnel Interferometric Imager prototype and made optical tests in our laboratory in order to validate the concept for future space missions. The primary module of this prototype consists of a square, 8 cm side, 23 m focal length Fresnel array. The focal module is composed of a diaphragmed small telescope used as "field lens," a small cophased diverging Fresnel zone lens that cancels the dispersion, and a detector. An additional module collimates the artificial targets of various shapes, sizes, and dynamic ranges to be imaged. We describe the experimental setup, different designs of the primary Fresnel array, and the cophased Fresnel zone lens that achieves rigorous chromatic correction. We give quantitative measurements of the diffraction limited performances and dynamic range on double sources. The tests have been performed in the visible domain, lambda = 400-700 nm. In addition, we present computer simulations of the prototype optics based on Fresnel propagation that corroborate the optical tests. This numerical tool has been used to simulate the large aperture Fresnel arrays that could be sent to space with diameters of 3 to 30 m, foreseen to operate from Lyman alpha (121 nm) to mid IR (25 microm).

  2. High-resolution, high-sensitivity, ground-based solar spectropolarimetry with a new fast imaging polarimeter. I. Prototype characterization

    NASA Astrophysics Data System (ADS)

    Iglesias, F. A.; Feller, A.; Nagaraju, K.; Solanki, S. K.

    2016-05-01

    Context. Remote sensing of weak and small-scale solar magnetic fields is of utmost relevance when attempting to respond to a number of important open questions in solar physics. This requires the acquisition of spectropolarimetric data with high spatial resolution (~10-1 arcsec) and low noise (10-3 to 10-5 of the continuum intensity). The main limitations to obtain these measurements from the ground, are the degradation of the image resolution produced by atmospheric seeing and the seeing-induced crosstalk (SIC). Aims: We introduce the prototype of the Fast Solar Polarimeter (FSP), a new ground-based, high-cadence polarimeter that tackles the above-mentioned limitations by producing data that are optimally suited for the application of post-facto image restoration, and by operating at a modulation frequency of 100 Hz to reduce SIC. Methods: We describe the instrument in depth, including the fast pnCCD camera employed, the achromatic modulator package, the main calibration steps, the effects of the modulation frequency on the levels of seeing-induced spurious signals, and the effect of the camera properties on the image restoration quality. Results: The pnCCD camera reaches 400 fps while keeping a high duty cycle (98.6%) and very low noise (4.94 e- rms). The modulator is optimized to have high (>80%) total polarimetric efficiency in the visible spectral range. This allows FSP to acquire 100 photon-noise-limited, full-Stokes measurements per second. We found that the seeing induced signals that are present in narrow-band, non-modulated, quiet-sun measurements are (a) lower than the noise (7 × 10-5) after integrating 7.66 min, (b) lower than the noise (2.3 × 10-4) after integrating 1.16 min and (c) slightly above the noise (4 × 10-3) after restoring case (b) by means of a multi-object multi-frame blind deconvolution. In addition, we demonstrate that by using only narrow-band images (with low S/N of 13.9) of an active region, we can obtain one complete set of high

  3. Illumination compensation in ground based hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Wendel, Alexander; Underwood, James

    2017-07-01

    Hyperspectral imaging has emerged as an important tool for analysing vegetation data in agricultural applications. Recently, low altitude and ground based hyperspectral imaging solutions have come to the fore, providing very high resolution data for mapping and studying large areas of crops in detail. However, these platforms introduce a unique set of challenges that need to be overcome to ensure consistent, accurate and timely acquisition of data. One particular problem is dealing with changes in environmental illumination while operating with natural light under cloud cover, which can have considerable effects on spectral shape. In the past this has been commonly achieved by imaging known reference targets at the time of data acquisition, direct measurement of irradiance, or atmospheric modelling. While capturing a reference panel continuously or very frequently allows accurate compensation for illumination changes, this is often not practical with ground based platforms, and impossible in aerial applications. This paper examines the use of an autonomous unmanned ground vehicle (UGV) to gather high resolution hyperspectral imaging data of crops under natural illumination. A process of illumination compensation is performed to extract the inherent reflectance properties of the crops, despite variable illumination. This work adapts a previously developed subspace model approach to reflectance and illumination recovery. Though tested on a ground vehicle in this paper, it is applicable to low altitude unmanned aerial hyperspectral imagery also. The method uses occasional observations of reference panel training data from within the same or other datasets, which enables a practical field protocol that minimises in-field manual labour. This paper tests the new approach, comparing it against traditional methods. Several illumination compensation protocols for high volume ground based data collection are presented based on the results. The findings in this paper are

  4. Preparation of JEREMI Experiment: Development of the Ground Based Prototype

    NASA Astrophysics Data System (ADS)

    Yasnou, V.; Mialdun, A.; Shevtsova, V.

    2012-12-01

    This study has been performed in the frame of preparing the space experiment JEREMI (Japanese and European Research Experiment on Marangoni Instabilities). The use of forced coaxial gas flow is proposed as a way to stabilize the Marangoni convection in liquid bridges, which might have important technological applications in the floating zone technique. A new set-up is under development and all sub-systems have passed severe tests. Here we present the design of this set-up and preliminary results of experiments for shear-driven two-phase flows in a confined volume of liquid under conditions of normal gravity. The geometry corresponds to a cylindrical liquid bridge concentrically surrounded by an annular gas channel with external solid walls. Gas enters into the annular duct, flows between solid walls and upon reaching the liquid zone entrains initially quiescent liquid. The test liquids are ethanol, n-decane and 5 cSt silicone oil, which have different degrees of viscosity and of volatility. The gas flow along the interface strongly enhances the evaporation and, correspondingly, affects the interface shape. Silhouette measurements are used for optical determination of the interface shape. From the digital images the variation of the liquid volume as a function of flow rate is calculated.

  5. Robust Image Restoration for Ground-Based Space Surveillance

    DTIC Science & Technology

    2013-09-01

    Figure 8 shows a different case in which the AO system was not running. This target is the Hubble Space Telescope and data were collected with...data. Both images are shown on a square root scale.     Figure 8. The Hubble Space Telescope . Left: Raw data frame with AO in open loop...Robust image restoration for ground-based space surveillance Douglas A. Hope, Michael Hart, Stuart M. Jefferies and James Nagy Hart Scientific

  6. [Development of a prototype of space vegetable-cultivating facility for ground-based experiments].

    PubMed

    Guo, Shuang-sheng; Liu, Xiang-yang; Han, Li-jun; Zhu, Jing-tao; Wang, Xiao-xia; Wei, Min; Ai, Wei-dang; Yang, Jing-song; Tang, Yong-kang

    2005-02-01

    To develop a ground-based experimental prototype of space vegetable-cultivating facility (GEPSVF), so as to solve the main key techniques related to higher plant cultivation in space environmental conditions, and to further lay a foundation for future development and application of the prototype of space vegetable-growing facility. Based on detailed demonstration and design of technique plan, the blueprint design and machining of components, whole facility installment, debugging, trial operations and verification experiments were done. The parameters in the growing chamber such as temperature, relative humidity, wind velocity, total pressure, O2 partial pressure, CO2 partial pressure and water content of the growing media were totally and effectively controlled; the light source was electronic fluorescent lamp; the average vegetable-producing output reached 60 g (fresh weight) d-1. The prototype could operate stably; its actual performance indexes achieved the expected ones basically; some of its operating principles can adapt to space microgravity condition. Therefore, the prototype is a good beginning for future development of space vegetable-producing facilities.

  7. Development of an improved ground-based prototype of space plant-growing facility

    NASA Astrophysics Data System (ADS)

    Guo, S.; Liu, X.; Ai, W.; Tang, Y.; Zhu, J.; Wang, X.; Wei, M.; Qin, L.; Yang, Y.

    Based on a formerly developed ground-based prototype of space plant-growing facility, the development of its improved prototype has been finished, so as to make its operating principle better adapt to the space microgravity environment. According to the developing experience of its first generation prototype and detailed demonstration and design of technique plan, its blueprint design and machining of related components, whole facility installment, debugging and trial operations were all done gradually. Its growing chamber contains a volume of about 0.5 m3 and a growing area of approximate 0.5 m2; the atmospheric environmental parameters in the growing chamber and water content in the growing media were controlled totally and effectively; lighting source is a combination of both red and blue light emitting diodes (LED). The following demonstrating results showed that the entire system design of the prototype is reasonable and its operating principle can nearly meet the requirements of space microgravity environment. Therefore, our plant-growing technique in space was advanced further, which laid an important foundation for next development of the space plant-growing facility and plant-cultivating experimental research in space microgravity condition.

  8. Research on ground-based LWIR hyperspectral imaging remote gas detection

    NASA Astrophysics Data System (ADS)

    Yang, Zhixiong; Yu, Chunchao; Zheng, Weijian; Lei, Zhenggang; Yan, Min; Yuan, Xiaochun; Zhang, Peizhong

    2015-10-01

    The new progress of ground-based long-wave infrared remote sensing is presented, which describes the windowing spatial and temporal modulation Fourier spectroscopy imaging in details. The prototype forms the interference fringes based on the corner-cube of spatial modulation of Michelson interferometer, using cooled long-wave infrared photovoltaic staring FPA (focal plane array) detector. The LWIR hyperspectral imaging is achieved by the process of collection, reorganization, correction, apodization, FFT etc. from data cube. Noise equivalent sensor response (NESR), which is the sensitivity index of CHIPED-1 LWIR hyperspectral imaging prototype, can reach 5.6×10-8W/(cm-1.sr.cm2) at single sampling. Hyperspectral imaging is used in the field of organic gas VOC infrared detection. Relative to wide band infrared imaging, it has some advantages. Such as, it has high sensitivity, the strong anti-interference ability, identify the variety, and so on.

  9. Ground-based prototype quantum cascade laser heterodyne radiometer for atmospheric studies

    NASA Astrophysics Data System (ADS)

    Weidmann, D.; Reburn, W. J.; Smith, K. M.

    2007-07-01

    The advent of quantum cascade lasers has provided matured continuously tunable solid state laser sources emitting from mid-infrared to terahertz wavelengths. Such sources, used as local oscillators, offer the practical prospect of aircraft, high altitude platform, and satellite deployment of compact and shot noise limited heterodyne radiometers for Earth observation and astronomy. A ground-based prototype of a quantum cascade laser heterodyne radiometer operating in the mid-infrared has been developed and is presented. The instrument design and concepts are described, together with evaluation of the instrument in the laboratory and during field measurements of atmospheric ozone. In this study the best performance achieved by the prototype quantum cascade laser heterodyne radiometer was a signal-to-noise ratio of three times the theoretical shot-noise limit. The prototype has allowed the main sources of excess noise to be identified as residual optical feedback in the local oscillator optical path and a lack of mechanical and thermal stability in the local oscillator collimation system. Instrument improvements are currently being implemented and enhanced performance is expected in the near future.

  10. Development of an improved ground-based prototype of space vegetable-producing facility

    NASA Astrophysics Data System (ADS)

    Liu, X.; Guo, S.; Zhu, J.; Wang, X.; Ai, W.; Wei, M.; Qin, L.; Deng, Y.

    Based on the development of a ground-based prototype of space vegetable-producing facility development of its improved prototype has been finished so as to make its operating principle adapt to the space microgravity environment better According to the developing experience of first-generation prototype of the space vegetable-producing facility and detailed demonstration and design of technique plan its blueprint design and machining of related components whole facility installment debugging and trial operations were done Its growing chamber contains a volume of about 0 5m 3 and a growing area of approximate 0 5m 2 the atmospheric environmental parameters in the growing chamber and water content in the growing media were totally and effectively controlled lighting sources are the combinations of both red and blue light emitting diode LED The following demonstrating results showed that the entire system design of the facility is reasonable and its operating principle can meet nearly the requirements of space microgravity environment Therefore our plant growing technique in space was advanced greatly which laid an important foundation for next development of the space vegetable-producing facility to be tested and applied in space station

  11. Retrieval algorithms for cloud motion from ground-based images

    NASA Astrophysics Data System (ADS)

    Bakalova, Kalinka

    We present the preliminary results of a project, focused on obtaining information about the velocity and direction of motion of air masses by means of ground-based measurements of visible cloud motion. This information can be used in short-term local weather forecast and is helpful in studies of the dynamics of the physical processes in clouds. We report the recent progress in the development of algorithms and tools for retrieving the three-dimensional field of vectors of velocity of cloud motion from time series of ground-based digital images. The visible motion of a cloud is the compound effect of the translational drift of the cloud as a whole with the velocity of the adjacent air masses, and of deformations due to the physical processes in the atmosphere. Because of the continuous changes of shape, extracting the translational component in the displacement of a cloud from a series of consecutive images is a highly non-trivial problem. Our approach consists in selecting a set of characteristic reference patterns of the cloud on the first image of the series, tracking them on the subsequent images, and evaluating this way the individual displacement of each reference pattern. Specific algorithms are being developed for the optimal choice of the reference patterns on the starting image and the recognition of these patterns on the subsequent images, depending on the type of the observed cloud. For clouds with low contrast or no edges, such as Stratus, Nimbostratus and Stratocumulus, implementations of the Optical Flow method are under development. For clouds with distinct contours, such as Cumulus and Altocumulus, the edges are decomposed into one-dimensional curvilinear patterns. To reduce the uncertainties, a multi-parametric model of the transformations of the cloud shape between images is defined next which, besides parallel transport, also involves dilatation, rotation, and possibly some local deformations. The parameters of the model are calculated from the

  12. Monitoring hemlock vitality using ground-based digital imaging

    Treesearch

    Neil A. Clark; Sang-Mook Lee

    2005-01-01

    The vitality of hemlock (Tsuga spp.) trees needs to be assessed in order to evaluate the effectiveness of treatments that combat hemlock woolly adelgid (HWA), Adelges tsugae Annand 1 (Homoptera: Adelgidae). Ground-based photomonitoring can be used to assess canopy dynamics, which serves as a visual indicator of tree vitality. Here we propose a...

  13. Compound auroral micromorphology: ground-based high-speed imaging

    NASA Astrophysics Data System (ADS)

    Kataoka, Ryuho; Fukuda, Yoko; Miyoshi, Yoshizumi; Miyahara, Hiroko; Itoya, Satoru; Ebihara, Yusuke; Hampton, Donald; Dahlgren, Hanna; Whiter, Daniel; Ivchenko, Nickolay

    2015-02-01

    Auroral microphysics still remains partly unexplored. Cutting-edge ground-based optical observations using scientific complementary metal-oxide semiconductor (sCMOS) cameras recently enabled us to observe the fine-scale morphology of bright aurora at magnetic zenith for a variety of rapidly varying features for long uninterrupted periods. We report two interesting examples of combinations of fine-scale rapidly varying auroral features as observed by the sCMOS cameras installed at Poker Flat Research Range (PFRR), Alaska, in February 2014. The first example shows that flickering rays and pulsating modulation simultaneously appeared at the middle of a surge in the pre-midnight sector. The second example shows localized flickering aurora associated with growing eddies at the poleward edge of an arc in the midnight sector.

  14. Simulation of the imaging quality of ground-based telescopes affected by atmospheric disturbances

    NASA Astrophysics Data System (ADS)

    Ren, Yubin; Kou, Songfeng; Gu, Bozhong

    2014-08-01

    Ground-based telescope imaging model is developed in this paper, the relationship between the atmospheric disturbances and the ground-based telescope image quality is studied. Simulation of the wave-front distortions caused by atmospheric turbulences has long been an important method in the study of the propagation of light through the atmosphere. The phase of the starlight wave-front is changed over time, but in an appropriate short exposure time, the atmospheric disturbances can be considered as "frozen". In accordance with Kolmogorov turbulence theory, simulating atmospheric disturbances of image model based on the phase screen distorted by atmospheric turbulences is achieved by the fast Fourier transform (FFT). Geiger mode avalanche photodiode array (APD arrays) model is used for atmospheric wave-front detection, the image is achieved by inversion method of photon counting after the target starlight goes through phase screens and ground-based telescopes. Ground-based telescope imaging model is established in this paper can accurately achieve the relationship between the quality of telescope imaging and monolayer or multilayer atmosphere disturbances, and it is great significance for the wave-front detection and optical correction in a Multi-conjugate Adaptive Optics system (MCAO).

  15. Advantages of using subsurface flow constructed wetlands for wastewater treatment in space applications: ground-based Mars Base prototype.

    PubMed

    Nelson, M; Alling, A; Dempster, W F; van Thillo, M; Allen, John

    2003-01-01

    Research and design of subsurface flow wetland wastewater treatment systems for a ground-based experimental prototype Mars Base facility has been carried out, using a subsurface flow approach. These systems have distinct advantages in planetary exploration scenarios: they are odorless, relatively low-labor and low-energy, assist in purification of water and recycling of atmospheric CO2, and will support some food crops. An area of 6-8 m2 may be sufficient for integration of wetland wastewater treatment with a prototype Mars Base supporting 4-5 people. Discharge water from the wetland system will be used as irrigation water for the agricultural crop area, thus ensuring complete recycling and utilization of nutrients. Since the primary requirements for wetland treatment systems are warm temperatures and lighting, such bioregenerative systems may be integrated into early Mars base habitats, since waste heat from the lights may be used for temperature maintenance in the human living environment. "Wastewater gardens (TM)" can be modified for space habitats to lower space and mass requirements. Many of its construction requirements can eventually be met with use of in-situ materials, such as gravel from the Mars surface. Because the technology requires little machinery and no chemicals, and relies more on natural ecological mechanisms (microbial and plant metabolism), maintenance requirements are minimized, and systems can be expected to have long operating lifetimes. Research needs include suitability of Martian soil and gravel for wetland systems, system sealing and liner options in a Mars Base, and wetland water quality efficiency under varying temperature and light regimes. c2003 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  16. Advantages of using subsurface flow constructed wetlands for wastewater treatment in space applications: Ground-based mars base prototype

    NASA Astrophysics Data System (ADS)

    Nelson, M.; Alling, A.; Dempster, W. F.; van Thillo, M.; Allen, John

    Research and design of subsurface flow wetland wastewater treatment systems for a ground-based experimental prototype Mars Base facility has been carried out, using a subsurface flow approach. These systems have distinct advantages in planetary exploration scenarios: they are odorless, relatively low-labor and low-energy, assist in purification of water and recycling of atmospheric CO2, and will support some food crops. An area of 6-8 m2 may be sufficient for integration of wetland wastewater treatment with a prototype Mars Base supporting 4-5 people. Discharge water from the wetland system will be used as irrigation water for the agricultural crop area, thus ensuring complete recycling and utilization of nutrients. Since the primary requirements for wetland treatment systems are warm temperatures and lighting, such bioregenerative systems may be integrated into early Mars base habitats, since waste heat from the lights may be used for temperature maintenance in the human living environment. "Wastewater gardens ™" can be modified for space habitats to lower space and mass requirements. Many of its construction requirements can eventually be met with use of in-situ materials, such as gravel from the Mars surface. Because the technology requires little machinery and no chemicals, and relies more on natural ecological mechanisms (microbial and plant metabolism), maintenance requirements are minimized, and systems can be expected to have long operating lifetimes. Research needs include suitability of Martian soil and gravel for wetland systems, system sealing and liner options in a Mars Base, and wetland water quality efficiency under varying temperature and light regimes.

  17. Improving the atmospheric wind speed measured accuracy by the ground-based airglow imaging interferometer

    NASA Astrophysics Data System (ADS)

    Tang, Yuanhe; Yang, Rui; Gao, Haiyang; Zhai, Fengtao; Yu, Yang; Cui, Jin

    2017-02-01

    A prototype ground based airglow imaging interferometer (GBAII) has been constructed to observe the upper atmospheric wind velocity and temperature at an altitude of 90-100 km, but the GBAII's wind speed accuracy was found to be unsatisfactory with a value of 21.0 m/s. Three theoretical aspects have been investigated to improve the accuracy, with the following finding: 1) By replacing the surface coatings of the GBAII's 6 lenses and Michelson interferometer (MI) with a new wind-speed infrared film rather than the original visible light film, the accuracy can be increased by 3.0 m/s. 2) By replacing the original charge-coupled device (CCD) with a quantum efficiency (QE) of 0.38 at the wavelength of approximately 866 nm by an electron multiplying CCD (EMCCD) with QE of 0.95, the accuracy can be increased by 6.7 m/s. By adding all the factors that improve the accuracy of the GBAII, it can be improved by 15.0 m/s, which realizes the original aim of wind speed accuracy of 6.0 m/s. Experimental results have been obtained for two aspects: 1) By replacing the surface film on the GBAII's 6 lenses and MI interface, the wind speed accuracy has been increased by 3.8 m/s. 2) A new GBAII temperature controller has been constructed to control the environmental temperature in 0.2 K steps. The results obtained by the GBAII on Dec. 6, 2013 show an average atmospheric temperature of 206.5 K, zonal wind speed of -26.8 m/s and meridional wind speed of 28.1 m/s. These results are close to those of the TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) satellite Doppler interferometer (TIDI) data collected at almost the same time.

  18. Measuring glacier surface temperatures with ground-based thermal infrared imaging

    NASA Astrophysics Data System (ADS)

    Aubry-Wake, Caroline; Baraer, Michel; McKenzie, Jeffrey M.; Mark, Bryan G.; Wigmore, Oliver; Hellström, Robert È.; Lautz, Laura; Somers, Lauren

    2015-10-01

    Spatially distributed surface temperature is an important, yet difficult to observe, variable for physical glacier melt models. We utilize ground-based thermal infrared imagery to obtain spatially distributed surface temperature data for alpine glaciers. The infrared images are used to investigate thermal microscale processes at the glacier surface, such as the effect of surface cover type and the temperature gradient at the glacier margins on the glacier's temperature dynamics. Infrared images were collected at Cuchillacocha Glacier, Cordillera Blanca, Peru, on 23-25 June 2014. The infrared images were corrected based on ground truth points and local meteorological data. For the control points, the Pearson's correlation coefficient between infrared and station temperatures was 0.95. The ground-based infrared camera has the potential for greatly improving glacier energy budget studies, and our research shows that it is critical to properly correct the thermal images to produce robust, quantifiable data.

  19. Prototype of a Laser-Induced Fluorescence Ground-Based Instrument for Measurements of Atmospheric Iodine Monoxide (IO)

    NASA Astrophysics Data System (ADS)

    Thurlow, M. E.; Co, D. T.; Hanisco, T. F.; Lapson, L. B.; Anderson, J. G.

    2008-12-01

    High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer: (1) IO participates in depletion episodes of O3 and in the removal of mercury in the Arctic polar spring by enhancing atomic Br mixing ratios. Recent observations and computer simulations suggest that mercury sequestration is closely tied to halogen photochemistry and that gaseous atomic Hg depletion can be enhanced significantly by the presence of small amounts of iodine-containing compounds. (2) IO and higher- order iodine oxides are involved in the formation of new particles in coastal marine environments. Studies using smog chamber experiments simulating coastal atmospheric conditions have demonstrated that new particles can form from condensable iodine-containing vapors and that their concentrations over the open ocean are sufficient to influence marine particle formation. (3) IO has also been shown to affect the oxidizing capacity of the troposphere by altering the partitioning of NO2/NO and HO2/HO and by activating chlorine and bromine in sea salt aerosols. In the stratosphere, these same processes can lead to enhanced ozone loss rates. Detailed photochemical models that include iodine photochemistry, however, are hampered by the lack of observational data. The distribution of IO in vertical, horizontal, and temporal coordinates is unknown, so the impact of IO on global photochemistry cannot be predicted. The resolution of these important scientific issues requires an in situ IO instrument. A fully functional nanosecond Nd:YAG-pumped Ti:Sapphire laser system and a prototype IO ground-based instrument have been built in our lab. With the current setup, the laser system was situated 10 m from the field station, and the laser light was coupled via an optical fiber. With the use of highly efficient fluorescence detection optics and photon counting techniques, sensitivities of better than 0.1 ppt in 1 s for IO was achieved in the

  20. Prototype of a Laser-Induced Fluorescence Ground-Based Instrument for Measurements of Atmospheric Iodine Monoxide (IO)

    NASA Astrophysics Data System (ADS)

    Co, D. T.; Thurlow, M. E.; Hanisco, T. F.; Lapson, L. B.; Anderson, J. G.

    2007-12-01

    High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer: (1) IO participates in depletion episodes of O3 and in the removal of mercury in the Arctic polar spring by enhancing atomic Br mixing ratios. Recent observations and computer simulations suggest that mercury sequestration is closely tied to halogen photochemistry and that gaseous atomic Hg depletion can be enhanced significantly by the presence of small amounts of iodine-containing compounds. (2) IO and higher- order iodine oxides are involved in the formation of new particles in coastal marine environments. Studies using smog chamber experiments simulating coastal atmospheric conditions have demonstrated that new particles can form from condensable iodine-containing vapors and that their concentrations over the open ocean are sufficient to influence marine particle formation. (3) IO has also been shown to affect the oxidizing capacity of the troposphere by altering the partitioning of NO2/NO and HO2/HO and by activating chlorine and bromine in sea salt aerosols. In the stratosphere, these same processes can lead to enhanced ozone loss rates. Detailed photochemical models that include iodine photochemistry, however, are hampered by the lack of observational data. The distribution of IO in vertical, horizontal, and temporal coordinates is unknown, so the impact of IO on global photochemistry cannot be predicted. The resolution of these important scientific issues requires an in situ IO instrument. A fully functional nanosecond Nd:YAG-pumped Ti:Sapphire laser system and a prototype IO ground-based instrument have been built in our lab. With the current setup, the laser system was situated 10 m from the field station, and the laser light was coupled via an optical fiber. With the use of highly efficient fluorescence detection optics and photon counting techniques, sensitivities of better than 0.1 ppt in 1 s for IO was achieved in the

  1. Networking ground-based images of Comet Halley during the Giotto encounter

    NASA Technical Reports Server (NTRS)

    Rees, David; Perla, Israel; Meredith, Nigel P.; Green, James; Van Der Heijden, Nick

    1986-01-01

    During the period immediately before and after the European, Russian, and Japanese spacecraft encounters with Comet Halley in early March 1986, sequences of ground-based electronic images of the comet, obtained at Table Mountain Observatory (TMO), CA, were transmitted via the Space Physics Analysis Network (SPAN) to the European Space Operations Centre (ESOC), and to University College London (UCL). During the 48-h period when the European Space Agency spacecraft Giotto was within the extended coma of Comet Halley, the ground-based images revealed that the comet displayed several spectacular near-nuclear and large-scale features. The TMO images provided a format for the interpretation of the unique in situ results obtained during the closest of the five spacecraft encounters with Comet Halley.

  2. Cloud Optical Depth Measured with Ground-Based, Uncooled Infrared Imagers

    NASA Technical Reports Server (NTRS)

    Shaw, Joseph A.; Nugent, Paul W.; Pust, Nathan J.; Redman, Brian J.; Piazzolla, Sabino

    2012-01-01

    Recent advances in uncooled, low-cost, long-wave infrared imagers provide excellent opportunities for remotely deployed ground-based remote sensing systems. However, the use of these imagers in demanding atmospheric sensing applications requires that careful attention be paid to characterizing and calibrating the system. We have developed and are using several versions of the ground-based "Infrared Cloud Imager (ICI)" instrument to measure spatial and temporal statistics of clouds and cloud optical depth or attenuation for both climate research and Earth-space optical communications path characterization. In this paper we summarize the ICI instruments and calibration methodology, then show ICI-derived cloud optical depths that are validated using a dual-polarization cloud lidar system for thin clouds (optical depth of approximately 4 or less).

  3. Wavelength dependence of star images formed by large ground-based telescopes including ELTs

    NASA Astrophysics Data System (ADS)

    McKechnie, T. Stewart

    2016-08-01

    Star image appearance in large ground-based telescopes is determined by the properties of the Optical Path Difference (OPD) fluctuation associated with the image-forming wave potions collected by the telescope aperture. The principal properties are the root mean square (rms) OPD fluctuation and the autocorrelation function of the OPD fluctuation. The OPD properties ultimately depend on the combined effects of turbulence in the atmospheric path, the fixed aberrations of the telescope and, if appropriate, the corrective effects of Adaptive Optics (AO). The equations given in this paper relating star image properties to the OPD properties (and also the inverse relations) apply to all large ground-based reflector telescopes, including ELTs. They apply equally to telescopes with and without AO. The OPD properties can be obtained directly from an image of an unresolved star. This image represents the intensity Point Spread Function (PSF) corresponding to the entire end-to-end imaging path. To obtain the full OPD information compliment, however, the image must be formed at a wavelength that delivers the most general type of star image: a core and halo image. Once the OPD properties have been obtained from such an image, the intensity PSF for the telescope/atmosphere/AO combination can immediately be calculated for any other wavelengths of interest in the extended optical wavelength range, 0.3 μm - 1000 μm. There are numerous applications for the mathematical relationships set out in this paper, including characterization of atmospheric paths, assessment of telescope/AO imaging performance, establishing wave front tolerances for ELTs and other large ground-based telescopes, and the rapid identification of sweetspot wavelength regions where highest resolution is achieved and star images attain maximum central intensity.

  4. Toward the Ground-based Imaging of Satellites at Geosynchronous Altitude

    DTIC Science & Technology

    2011-09-01

    these fall quite a bit short of our requirements. As a result, we considered an imaging interferometer . The exiting facilities do not have enough...fibers. Over a traditional ground-based interferometer , sensitivity is improved since losses due to the vacuum feed system and delay lines are...Std Z39-18 Figure 1: The concept described in this paper is an optical interferometer mounted on a steerable platform. Light from the apertures is

  5. Ground-based Imager and Magnetometer Network for Auroral STudies (GIMNAST)

    NASA Astrophysics Data System (ADS)

    Frey, H. U.; Mende, S. B.

    2012-12-01

    A large network of all-sky cameras and ground based magnetometers has been installed in Canada, Alaska, and Greenland as part of the NASA Midex Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission. In connection with plasma measurements in the deep magnetotail that system has been extremely valuable for the determination of auroral effects prior to substorm onset. Now that two of the THEMIS spacecraft became ARTEMIS in their orbits around the moon and the orbits of the remaining near-Earth three THEMIS satellites have drifted away from their conjunctions over North America during northern winter, the ground-based system has become less valuable for the space mission. However, the National Science Foundation agreed to support the continued operation of the Alaska and Greenland sites under the new name Ground-based Imager and Magnetometer Network for Auroral STudies (GIMNAST). The sites are now extremely valuable in support of radar measurements by the Advanced Modular Incoherent Scatter Radar (AMISR) in Poker Flat (PFISR), rocket launches out of Poker Flat, and the global ionospheric monitoring by the Super Dual Auroral radar Network (SuperDARN). We will present results of recent collaborations between GIMNAST and external users.

  6. Ground-based RGB imaging to determine the leaf water potential of potato plants

    NASA Astrophysics Data System (ADS)

    Zakaluk, Robert F.

    The determination of plant water status from leaf water potential (Psi L) data obtained by conventional methods is impractical for meeting real time irrigation monitoring requirements. This research, undertaken first, in a greenhouse and then in the field, examined the use of artificial neural network (ANN) modeling of RGB (red green blue) images, captured by a ground-based, five mega pixel digital camera, to predict the leaf water potential of potato (Solanum tuberosum L). The greenhouse study examined cv. Russet Burbank, while the field study examined cv. Sangre. The protocol was similar in both studies: (1) images were acquired over different soil nitrate (N) and volumetric water content levels, (2) images were radiometrically calibrated, (3) green foliage was classified and extracted from the images, and (4) image transformations, and vegetation indices were calculated and transformed using principal components analysis (PCA). The findings from both studies were similar: (1) the R and G bands were more important than the B image band in the classification of green leaf pigment, (2) soil N showed an inverse linear relationship against leaf reflectance in the G image band, (3) the ANN model input neuron weights with more separation between soil N and PsiL were more important than other input neurons in predicting PsiL, and (4) the measured and predicted PsiL validation datasets were normally distributed with equal variances and means that were not significantly different. Based on these research findings, the ground-based digital camera proved to be an adequate sensor for image acquisition and a practical tool for acquiring data for predicting the PsiL of potato plants. Keywords: nitrogen, IHS transformation, chromaticity transformation, principal components, vegetation indices, remote sensing, artificial neural network, digital camera.

  7. AOLI: near-diffraction limited imaging in the visible on large ground-based telescopes

    NASA Astrophysics Data System (ADS)

    Mackay, Craig; Rebolo, Rafael; King, David L.; Labadie, Lucas; Puga, Marta; Pérez Garrido, Antonio; Colodro-Conde, Carlos; Lopez, Roberto L.; Muthusubramanian, Balaji; Oscoz, Alejandro; Rodríguez Ramos, J.; Rodrigo-Ramos, Luis F.; Fernandez-Valdivia, J. J.; Velasco, Sergio

    2016-08-01

    The combination of Lucky Imaging with a low order adaptive optics system was demonstrated very successfully on the Palomar 5m telescope nearly 10 years ago. It is still the only system to give such high-resolution images in the visible or near infrared on ground-based telescope of faint astronomical targets. The development of AOLI for deployment initially on the WHT 4.2 m telescope in La Palma, Canary Islands, will be described in this paper. In particular, we will look at the design and status of our low order curvature wavefront sensor which has been somewhat simplified to make it more efficient, ensuring coverage over much of the sky with natural guide stars as reference object. AOLI uses optically butted electron multiplying CCDs to give an imaging array of 2000 x 2000 pixels.

  8. Retrievals of atmospheric variables on the gas giants from ground-based mid-infrared imaging

    NASA Astrophysics Data System (ADS)

    Fletcher, L. N.; Orton, G. S.; Yanamandra-Fisher, P.; Fisher, B. M.; Parrish, P. D.; Irwin, P. G. J.

    2009-03-01

    Thermal-infrared imaging of Jupiter and Saturn using the NASA/IRTF and Subaru observatories are quantitatively analyzed to assess the capabilities for reproducing and extending the zonal mean atmospheric results of the Cassini/CIRS experiment. We describe the development of a robust, systematic and reproducible approach to the acquisition and reduction of planetary images in the mid-infrared (7-25 μm), and perform an adaptation and validation of the optimal estimation, correlated- k retrieval algorithm described by Irwin et al. [Irwin, P., Teanby, N., de Kok, R., Fletcher, L., Howett, C., Tsang, C., Wilson, C., Calcutt, S., Nixon, C., Parrish, P., 2008. J. Quant. Spectrosc. Radiat. Trans. 109 (6), 1136-1150] for channel-integrated radiances. Synthetic spectral analyses and a comparison to Cassini results are used to verify our abilities to retrieve temperatures, haze opacities and gaseous abundances from filtered imaging. We find that ground-based imaging with a sufficiently high spatial resolution is able to reproduce the three-dimensional temperature and para-H 2 fields measured by spacecraft visiting Jupiter and Saturn, allowing us to investigate vertical wind shear, pressure and, with measured cloud-top winds, Ertel potential vorticity on potential temperature surfaces. Furthermore, by scaling vertical profiles of NH 3, PH 3, haze opacity and hydrocarbons as free parameters during thermal retrievals, we can produce meridional results comparable with CIRS spectroscopic investigations. This paper demonstrates that mid-IR imaging instruments operating at ground-based observatories have access to several dynamical and chemical diagnostics of the atmospheric state of the gas giants, offering the prospect for quantitative studies over much longer baselines and often covering much wider areas than is possible from spaceborne platforms.

  9. (21) Lutetia spectrophotometry from Rosetta-OSIRIS images and comparison to ground-based observations

    NASA Astrophysics Data System (ADS)

    Magrin, S.; La Forgia, F.; Pajola, M.; Lazzarin, M.; Massironi, M.; Ferri, F.; da Deppo, V.; Barbieri, C.; Sierks, H.; Osiris Team

    2012-06-01

    Here we present some preliminary results on surface variegation found on (21) Lutetia from ROSETTA-OSIRIS images acquired on 2010-07-10. The spectrophotometry obtained by means of the two cameras NAC and WAC (Narrow and Wide Angle Cameras) is consistent with ground based observations, and does not show surface diversity above the data error bars. The blue and UV images (shortward 500 nm) may, however, indicate a variegation of the optical properties of the asteroid surface on the Baetica region (Sierks et al., 2011). We also speculate on the contribution due to different illumination and to different ground properties (composition or, more probably, grain size diversity). In particular a correlation with geologic units independently defined by Massironi et al. (2012) is evident, suggesting that the variegation of the ground optical properties is likely to be real.

  10. Progress toward studies of bubble-geometry Bose-Einstein condensates in microgravity with a ground-based prototype of NASA CAL

    NASA Astrophysics Data System (ADS)

    Lundblad, Nathan; Jarvis, Thomas; Paseltiner, Daniel; Lannert, Courtney

    2016-05-01

    We have proposed using NASA's Cold Atom Laboratory (CAL, launching to the International Space Station in 2017) to generate bubble-geometry Bose-Einstein condensates through radiofrequency dressing of an atom-chip magnetic trap. This geometry has not been truly realized terrestrially due to the perturbing influence of gravity, making it an ideal candidate for microgravity investigation aboard CAL. We report progress in the construction of a functional prototype of the orbital BEC apparatus: a compact atom-chip machine loaded by a 2D+MOT source, conventional 3D MOT, quadrupole trap, and transfer coil. We also present preliminary modeling of the dressed trap uniformity, which will crucially inform the geometric closure of the BEC shell surface as atom number, bubble radius, and bubble aspect ratio are varied. Finally, we discuss plans for experimental sequences to be run aboard CAL guided by intuition from ground-based prototype operation. JPL 1502172.

  11. Laser Guidestar Satellite for Ground-based Adaptive Optics Imaging of Geosynchronous Satellites and Astronomical Targets

    NASA Astrophysics Data System (ADS)

    Marlow, W. A.; Cahoy, K.; Males, J.; Carlton, A.; Yoon, H.

    2015-12-01

    Real-time observation and monitoring of geostationary (GEO) satellites with ground-based imaging systems would be an attractive alternative to fielding high cost, long lead, space-based imagers, but ground-based observations are inherently limited by atmospheric turbulence. Adaptive optics (AO) systems are used to help ground telescopes achieve diffraction-limited seeing. AO systems have historically relied on the use of bright natural guide stars or laser guide stars projected on a layer of the upper atmosphere by ground laser systems. There are several challenges with this approach such as the sidereal motion of GEO objects relative to natural guide stars and limitations of ground-based laser guide stars; they cannot be used to correct tip-tilt, they are not point sources, and have finite angular sizes when detected at the receiver. There is a difference between the wavefront error measured using the guide star compared with the target due to cone effect, which also makes it difficult to use a distributed aperture system with a larger baseline to improve resolution. Inspired by previous concepts proposed by A.H. Greenaway, we present using a space-based laser guide starprojected from a satellite orbiting the Earth. We show that a nanosatellite-based guide star system meets the needs for imaging GEO objects using a low power laser even from 36,000 km altitude. Satellite guide star (SGS) systemswould be well above atmospheric turbulence and could provide a small angular size reference source. CubeSatsoffer inexpensive, frequent access to space at a fraction of the cost of traditional systems, and are now being deployed to geostationary orbits and on interplanetary trajectories. The fundamental CubeSat bus unit of 10 cm cubed can be combined in multiple units and offers a common form factor allowing for easy integration as secondary payloads on traditional launches and rapid testing of new technologies on-orbit. We describe a 6U CubeSat SGS measuring 10 cm x 20 cm x

  12. Ground-based imaging remote sensing of ice clouds: uncertainties caused by sensor, method and atmosphere

    NASA Astrophysics Data System (ADS)

    Zinner, Tobias; Hausmann, Petra; Ewald, Florian; Bugliaro, Luca; Emde, Claudia; Mayer, Bernhard

    2016-09-01

    In this study a method is introduced for the retrieval of optical thickness and effective particle size of ice clouds over a wide range of optical thickness from ground-based transmitted radiance measurements. Low optical thickness of cirrus clouds and their complex microphysics present a challenge for cloud remote sensing. In transmittance, the relationship between optical depth and radiance is ambiguous. To resolve this ambiguity the retrieval utilizes the spectral slope of radiance between 485 and 560 nm in addition to the commonly employed combination of a visible and a short-wave infrared wavelength.An extensive test of retrieval sensitivity was conducted using synthetic test spectra in which all parameters introducing uncertainty into the retrieval were varied systematically: ice crystal habit and aerosol properties, instrument noise, calibration uncertainty and the interpolation in the lookup table required by the retrieval process. The most important source of errors identified are uncertainties due to habit assumption: Averaged over all test spectra, systematic biases in the effective radius retrieval of several micrometre can arise. The statistical uncertainties of any individual retrieval can easily exceed 10 µm. Optical thickness biases are mostly below 1, while statistical uncertainties are in the range of 1 to 2.5.For demonstration and comparison to satellite data the retrieval is applied to observations by the Munich hyperspectral imager specMACS (spectrometer of the Munich Aerosol and Cloud Scanner) at the Schneefernerhaus observatory (2650 m a.s.l.) during the ACRIDICON-Zugspitze campaign in September and October 2012. Results are compared to MODIS and SEVIRI satellite-based cirrus retrievals (ACRIDICON - Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems; MODIS - Moderate Resolution Imaging Spectroradiometer; SEVIRI - Spinning Enhanced Visible and Infrared Imager). Considering the identified

  13. Neptune's cloud structure in 1989 - Photometric variations and correlation with ground-based images

    NASA Technical Reports Server (NTRS)

    Lockwood, G. W.; Thompson, D. T.; Hammel, H. B.; Birch, P.; Candy, M.

    1991-01-01

    Ground-based photoelectric photometry in b, y, and the 6190 and 7250 A methane-bands, as well as spectrum scans of the methane 6190 A band and CCD images at 6190 and 8900 A, were obtained for Neptune during Voyager 2's approach of that planet on August 24, 1989. Photometric variations are presently correlated with the disk transit of bright planetary features, and the changes in feature distribution and brightness noted in the results are evaluated for implications bearing on long-term variability. It is suggested that the long-term secular variation is related to a slow change in a size of location of both the bright companion and the Great Dark Spot.

  14. Tropospheric water vapor imaging by combination of ground-based and spaceborne GNSS sounding data

    NASA Astrophysics Data System (ADS)

    Foelsche, Ulrich; Kirchengast, Gottfried

    2001-11-01

    The Global Navigation Satellite System (GNSS) comprises the U.S. system GPS (Global Positioning System), its Russian pendant GLONASS, and presumably, in the future, the European system Galileo. The potential of GNSS-based phase delay measurements for accurately estimating vertically and slant-path-integrated water vapor has been demonstrated recently for radio links between GPS satellites and ground-based GPS receivers. GNSS-based radio occultation, on the other hand, has been demonstrated via the GPS/Meteorology experiment to deliver accurate near-vertical profiles of atmospheric variables such as temperature and humidity with high vertical resolution. Height-resolving imaging of atmospheric water vapor becomes feasible when occultation profiles from spaceborne receivers in Low Earth Orbits (LEO) are combined with ground-based GNSS data from a colocated receiver network. We developed a two-dimensional, height-resolving tomographic imaging technique following the Bayesian approach for optimal combination of information from different sources. Using simulated GNSS-based water vapor measurements from LEO and ground, we show representative results derived from simple synthetic refractivity fields as well as from a realistic refractivity field based on a European Centre for Medium-Range Weather Forecasts (ECMWF) analysis. For cases located poleward of ˜40° we found a new simple mapping function to perform best within our forward model scheme, where the only free parameter is the climatological scale height in the troposphere, the exact value of which is not critical. The mapping function exploits the ratio between the straight-line ray path length within the first two scale heights above surface and the "effective height" defined by these first two scale heights. We found our technique capable of reconstructing atmospheric features like water vapor maxima near the top of the trade wind inversion. Adjustment of the integral over the water vapor profile measurements to

  15. Modeling the Variations in TSI Using Precision Ground-Based Photometric Images

    NASA Astrophysics Data System (ADS)

    Chapman, G. A.; Walton, S. R.; Cookson, A. M.; Dobias, J. J.; Preminger, D. G.

    2002-12-01

    Precision photometric full-disk images of the sun have been obtained at the San Fernando Observatory (SFO) beginning in mid-1985. Images in several wavelengths are obtained daily but for modeling the Total Solar Irradiance (TSI) from spacecraft, the red (672 nm) and the K-line (393 nm) images have been the most useful. Two telescopes are in regular operation, Cartesian Full Disk Telescope (CFDT) number 1 and 2. They produce images that have 512 x 512 pixels and 1024 x 1024 pixels, respectively. Multiple linear regressions of sunspot deficits and facular excesses compared with Nimbus-7 and ACRIM-I values of TSI give values of R2 of from 0.80 to 0.85, depending on data intervals and the particular spacecraft. More recent fits to the composite TSI of Fröhlich and Lean for cycle 22 give values of R2 of 0.91. These fits are affected by noise in both ground-based and space-based data. This value of R2 suggests, especially considering the effects of noise, that less than 10% of the TSI variance is unexplained by the effects of sunspots and faculae/network. We are in the process of determining whether or not the coefficients from fits to cycle 22 TSI will also provide good fits to cycle 23 TSI. This research has been partially supported by grants from NSF (ATM-9912132) and NASA (NAG5-7191 and NAG5-7778).

  16. Ground-based imaging spectrometry of canopy phenology and chemistry in a deciduous forest

    NASA Astrophysics Data System (ADS)

    Toomey, M. P.; Friedl, M. A.; Frolking, S. E.; Hilker, T.; O'Keefe, J.; Richardson, A. D.

    2013-12-01

    Phenology, annual life cycles of plants and animals, is a dynamic ecosystem attribute and an important feedback to climate change. Vegetation phenology is commonly monitored at canopy to continental scales using ground based digital repeat photography and satellite remote sensing, respectively. Existing systems which provide sufficient temporal resolution for phenological monitoring, however, lack the spectral resolution necessary to investigate the coupling of phenology with canopy chemistry (e.g. chlorophyll, nitrogen, lignin-cellulose content). Some researchers have used narrowband (<10 nm resolution) spectrometers at phenology monitoring sites, yielding new insights into seasonal changes in leaf biochemistry. Such instruments integrate the spectral characteristics of the entire canopy, however, masking considerable variability between species and plant functional types. There is an opportunity, then, for exploring the potential of imaging spectrometers to investigate the coupling of canopy phenology and the leaf biochemistry of individual trees. During the growing season of April-October 2013 we deployed an imaging spectrometer with a spectral range of 371-1042 nm and resolution of ~5 nm (Surface Optics Corporation 710; San Diego, CA) on a 35 m tall tower at the Harvard Forest, Massachusetts. The image resolution was ~0.25 megapixels and the field of view encompassed approximately 20 individual tree crowns at a distance of 20-40 m. The instrument was focused on a mixed hardwoods canopy composed of 4 deciduous tree species and one coniferous tree species. Scanning was performed daily with an acquisition frequency of 30 minutes during daylight hours. Derived imagery were used to calculate a suite of published spectral indices used to estimate foliar content of key pigments: cholorophyll, carotenoids and anthocyanins. Additionally, we calculated the photochemical reflectance index (PRI) as well as the position and slope of the red edge as indicators of mid- to

  17. Three-dimensional Structure of the Io Plasma Torus from Ground-based Images

    NASA Astrophysics Data System (ADS)

    Weiss, J. W.; Schneider, N. M.

    2000-10-01

    Ground-based imaging has provided key constraints on the structure of the Io plasma torus (e.g., Schneider & Trauger, ApJ. 450, p. 450, 1995), but most analyses have not tapped the full potential of the data. In most cases, images are analyzed for peak intensities, relative intensity variations, or overall morphology. One study of longitudinal variations showed the value of detailed numerical modeling (Schneider, N. M. et al. , "On the nature of the l III brightness asymmetry in the Io torus", JGR, 102, 19823-19833, 1997.), but the fitting algorithm was not sufficiently robust or efficient to extend to other data. We report on a comprehensive effort to derive the three-dimensional structure of the torus using an automated fitting algorithm. The image database includes the S+ images from Schneider & Trauger 1995, but additional images from other nights and other wavelengths will be added. The core of the fitting algorithm is the Colorado Io Torus Emissions Package (CITEP), a routine which simulates torus intensities based on plasma property inputs (Taylor, M.H et al. , "A comparison of the Voyager 1 ultraviolet spectrometer and plasma science measurements of the Io Plasma Torus", JGR . 100, 19541-50, 1995.). Our fitting algorithm uses IDL's down-hill simplex method to minimize a modified reduced-χ2 goodness of fit measure, finding densities and ion temperatures over the 4.5-6.5 Rj range. Fitting a single image provides these quantities at the torus 'ansas'; the three-dimensional structure comes from fitting a series of images spanning a complete rotation. Our results will focus on the longitudinal variations in density and ion temperature, and changes in structure from night to night. We will also extend modeling to S++ in order to place better constraints on overall plasma properties. This work has been supported by NASA's Planetary Astronomy Program.

  18. Ground-based thermal imaging of groundwater flow processes at the seepage face

    NASA Astrophysics Data System (ADS)

    Deitchman, Richard S.; Loheide, Steven P.

    2009-07-01

    There is no existing method to quantitatively image groundwater processes along a seepage face. Thus, it is often difficult to quantify the magnitude and spatial variability of groundwater flux. The objective of this work is to assess the use of ground-based thermal remote sensing for fine-scale mapping of groundwater discharge and for locating the water table position along a stream bank seepage face. Seepage faces are poorly understood and often neglected in regional hydrologic studies though they likely exert significant influence on hydrologic and ecologic processes in riparian zones. Although the importance of riparian areas is broadly recognized, our ability to quantify hydrologic, ecologic and biogeochemical processes and ecosystem services is hampered by our inability to characterize spatially variable processes such as groundwater discharge. This work employs a new, transferable, non-invasive method that uses heat as a natural tracer to image spatially-variable groundwater flow processes and distinguish between focused and diffuse groundwater discharge to the surface. We report, for the first time, that thermal remote sensing of groundwater at the seepage face provides indirect imaging of both the saturated zone-unsaturated zone transition and groundwater flux at the centimeter scale, offering insight into flow heterogeneity.

  19. Ground-based Observation System Development for the Moon Hyper-spectral Imaging

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Huang, Yu; Wang, Shurong; Li, Zhanfeng; Zhang, Zihui; Hu, Xiuqing; Zhang, Peng

    2017-05-01

    The Moon provides a suitable radiance source for on-orbit calibration of space-borne optical instruments. A ground-based observation system dedicated to the hyper-spectral radiometry of the Moon has been developed for improving and validating the current lunar model. The observation instrument using a dispersive imaging spectrometer is particularly designed for high-accuracy observations of the lunar radiance. The simulation and analysis of the push-broom mechanism is made in detail for lunar observations, and the automated tracking and scanning is well accomplished in different observational condition. A three-month series of hyper-spectral imaging experiments of the Moon have been performed in the wavelength range from 400 to 1000 nm near Lijiang Observatory (Yunnan, China) at phase angles -83°-87°. Preliminary results and data comparison are presented, and it shows the instrument performance and lunar observation capability of this system are well validated. Beyond previous measurements, this observation system provides the entire lunar disk images of continuous spectral coverage by adopting the push-broom mode with special scanning scheme and leads to the further research of lunar photometric model.

  20. Automated Detection and Tracking of Equatorial Plasma Depletions Using Ground-Based Optical Imagers

    NASA Astrophysics Data System (ADS)

    Pedersen, T.; Carrano, C.; Griffin, J.

    2004-12-01

    Optical imaging is one of the few means available for determining space weather parameters simultaneously over large areas, but tropospheric cloud cover presents a significant barrier to operational use of data from ground-based optical instruments. Distributed sensors experiencing different tropospheric conditions but with overlapping fields of view in the upper atmosphere are one possible solution to the cloud cover difficulty, while intelligent processing of imager data to discriminate between clouds and upper atmospheric features is another potential means of providing reliable data output from only a single instrument. We evaluate and discuss a variety of processing algorithms developed or adapted for the purpose of detecting and tracking equatorial plasma depletions in all-sky imager data under realistic conditions including significant cloud cover. Our most successful technique thus far relies on discrimination between depletions and other image features based on their signatures in velocity and correlation space rather than physical coordinates. In addition to allowing identification and tracking of the depletions, accurate knowledge of the velocity allows multiple frames of image data to be processed coherently in the reference frame moving with the depletions. This processing can virtually eliminate cloud effects up to 50 percent cloud cover. With externally provided velocity information (such as from a spaced-antenna scintillation system, for example) or an improved velocity algorithm, useful data can be obtained at even greater cloud cover fractions. A similar motion-based technique can also be applied to the background star field, allowing stars to be easily distinguished from pixel noise and hot pixels for rapid automatic identification of image regions affected by clouds without the need to identify, locate, or track any specific stars.

  1. Super-Gaussian apodization in ground based telescopes for high contrast coronagraph imaging.

    PubMed

    Cagigas, Miguel A; Valle, Pedro J; Cagigal, Manuel P

    2013-05-20

    We introduce the use of Super-Gaussian apodizing functions in the telescope pupil plane and/or the coronagraph Lyot plane to improve the imaging contrast in ground-based coronagraphs. We describe the properties of the Super-Gaussian function, we estimate its second-order moment in the pupil and Fourier planes and we check it as an apodizing function. We then use Super-Gaussian function to apodize the telescope pupil, the coronagraph Lyot plane or both of them. The result is that a proper apodizing masks combination can reduce the exoplanet detection distance up to a 45% with respect to the classic Lyot coronagraph, for moderately aberrated wavefronts. Compared to the prolate spheroidal function the Super-Gaussian apodizing function allows the planet light up to 3 times brighter. An extra help to increase the extinction rate is to perform a frame selection (Lucky Imaging technique). We show that a selection of the 10% best frames will reduce up to a 20% the detection angular distance when using the classic Lyot coronagraph but that the reduction is only around the 5% when using an apodized coronagraph.

  2. Compressed Sensing for Millimeter-wave Ground Based SAR/ISAR Imaging

    NASA Astrophysics Data System (ADS)

    Yiğit, Enes

    2014-11-01

    Millimeter-wave (MMW) ground based (GB) synthetic aperture radar (SAR) and inverse SAR (ISAR) imaging are the powerful tools for the detection of foreign object debris (FOD) and concealed objects that requires wide bandwidths and highly frequent samplings in both slow-time and fast-time domains according to Shannon/Nyquist sampling theorem. However, thanks to the compressive sensing (CS) theory GB-SAR/ISAR data can be reconstructed by much fewer random samples than the Nyquist rate. In this paper, the impact of both random frequency sampling and random spatial domain data collection of a SAR/ISAR sensor on reconstruction quality of a scene of interest was studied. To investigate the feasibility of using proposed CS framework, different experiments for various FOD-like and concealed object-like targets were carried out at the Ka and W band frequencies of the MMW. The robustness and effectiveness of the recommend CS-based reconstruction configurations were verified through a comparison among each other by using integrated side lobe ratios (ISLR) of the images.

  3. Ground-based infrared surveys: imaging the thermal fields at volcanoes and revealing the controlling parameters.

    NASA Astrophysics Data System (ADS)

    Pantaleo, Michele; Walter, Thomas

    2013-04-01

    Temperature monitoring is a widespread procedure in the frame of volcano hazard monitoring. Indeed temperature changes are expected to reflect changes in volcanic activity. We propose a new approach, within the thermal monitoring, which is meant to shed light on the parameters controlling the fluid pathways and the fumarole sites by using infrared measurements. Ground-based infrared cameras allow one to remotely image the spatial distribution, geometric pattern and amplitude of fumarole fields on volcanoes at metre to centimetre resolution. Infrared mosaics and time series are generated and interpreted, by integrating geological field observations and modeling, to define the setting of the volcanic degassing system at shallow level. We present results for different volcano morphologies and show that lithology, structures and topography control the appearance of fumarole field by the creation of permeability contrasts. We also show that the relative importance of those parameters is site-dependent. Deciphering the setting of the degassing system is essential for hazard assessment studies because it would improve our understanding on how the system responds to endogenous or exogenous modification.

  4. Laser Guidestar Satellite for Ground-based Adaptive Optics Imaging of Geosynchronous Satellites

    NASA Astrophysics Data System (ADS)

    Marlow, W.; Carlton, A.; Yoon, H.; Clark, J.; Haughwout, C.; Cahoy, K.; Males, J.; Close, L.; Morzinski, K.

    2016-09-01

    In this study, we assess the utility of using a maneuverable nanosatellite laser guidestar from a geostationary equatorial orbit to enable ground-based, adaptive optics imaging of geosynchronous satellites with next-generation extremely large telescopes. The concept for a satellite guide star was rst discussed in the literature by Greenaway in the early 1990s, and expanded upon by Albert in 2012. With a satellite-based laser as an adaptive optics guidestar, the source laser does not need to scatter, and is well above atmospheric turbulence. When viewed from the ground through a turbulent atmosphere, the angular size of the satellite guidestar is much smaller than a back-scattered source. Advances in small satellite technology and capability allow us to revisit the concept on a 6U CubeSat, measuring 10 cm by 20 cm by 30 cm. We show that a system that uses a satellite-based laser transmitter can be relatively low power (1 W transmit power), operated intermittently, and requires little propellant to relocate within the geosynchronous belt. We present results of a design study on the feasibility of a small satellite guidestar and highlight the potential benets to the space situational awareness community.

  5. a Ground-Based LIDAR and Imaging Spectrometer Synchronous Experiment on Vegetation

    NASA Astrophysics Data System (ADS)

    Hong, T.; Luo, X.; Chen, H.; Hui, J.

    2017-09-01

    Extraction of vegetation canopy structure parameters is of great significance for researching global ecosystem and environment. Focused on the effective synergy between active and passive sensors, we carried out some ground-based observations about different vegetation on different terrains. In different experimental sites, a light detection and ranging (LiDAR) data and an imaging spectrum data of typical vegetation were collected from different directions and angles. Meanwhile, a variety of canopy structure parameters, including plant height, crown breadth, leaf area index, etc, were measured. The whole observed results form a comprehensive ground synchronous data set corresponding to flight data and provide data support for development and validation of synergic retrieval methods of vegetation canopy structure parameters. Our specific experimental objectives and design are introduced, including the selection of sampling plots, arrangement of observation stations, acquisition of active and passive data, and measurement of auxiliary data. The processing and practical applications of those obtained synchronous data are also discussed. Finally, our experimental experience is summarized and it is a valuable reference for remote sensing researchers.

  6. Ground-based multispectral high-speed imaging of flickering aurora

    NASA Astrophysics Data System (ADS)

    Kataoka, Ryuho; Miyoshi, Yoshizumi; Sakanoi, Takeshi; Yaegashi, Ayumi; Ebihara, Yusuke; Shiokawa, Kazuo

    2011-07-01

    It has been suggested that dispersive Alfven waves (DAWs) are capable of accelerating electrons via Landau resonance, and the interference of DAWs plays an essential role to create flickering auroral patterns. Here we show evidence that the leading front of a typical interference pattern is more energetic than the trailing part, based on ground-based high-speed imaging observations at wavelengths of 670.5 nm and 844.6 nm, which are sensitive to relatively hard and soft electrons, respectively. The fine spatial resolution of 9.5 deg field-of-view at magnetic zenith and the 100 Hz sampling rate of electron multiplying charge-coupled device (EMCCD) enabled us to resolve the spatiotemporal variation of the flickering aurora. It is found that there is only 10 ms time delay with 0.5 km spatial shift on average in the obtained flickering patterns at two wavelengths. The time delay and spatial shift can be comprehensively explained by the traveling inhomogeneous interference pattern of DAWs, probably associated with the Landau damping and/or time-of-flight effect, which is only detectable using the highest resolved temporal and spatial observations of flickering aurora.

  7. Volcano geodesy at Santiaguito using ground-based cameras and particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Johnson, J.; Andrews, B. J.; Anderson, J.; Lyons, J. J.; Lees, J. M.

    2012-12-01

    The active Santiaguito dome in Guatemala is an exceptional field site for ground-based optical observations owing to the bird's-eye viewing perspective from neighboring Santa Maria Volcano. From the summit of Santa Maria the frequent (1 per hour) explosions and continuous lava flow effusion may be observed from a vantage point, which is at a ~30 degree elevation angle, 1200 m above and 2700 m distant from the active vent. At these distances both video cameras and SLR cameras fitted with high-power lenses can effectively track blocky features translating and uplifting on the surface of Santiaguito's dome. We employ particle image velocimetry in the spatial frequency domain to map movements of ~10x10 m^2 surface patches with better than 10 cm displacement resolution. During three field campaigns to Santiaguito in 2007, 2009, and 2012 we have used cameras to measure dome surface movements for a range of time scales. In 2007 and 2009 we used video cameras recording at 30 fps to track repeated rapid dome uplift (more than 1 m within 2 s) of the 30,000 m^2 dome associated with the onset of eruptive activity. We inferred that the these uplift events were responsible for both a seismic long period response and an infrasound bimodal pulse. In 2012 we returned to Santiaguito to quantify dome surface movements over hour-to-day-long time scales by recording time lapse imagery at one minute intervals. These longer time scales reveal dynamic structure to the uplift and subsidence trends, effusion rate, and surface flow patterns that are related to internal conduit pressurization. In 2012 we performed particle image velocimetry with multiple cameras spatially separated in order to reconstruct 3-dimensional surface movements.

  8. Radiometric modeling and calibration of the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) ground based measurement experiment

    NASA Astrophysics Data System (ADS)

    Tian, Jialin; Smith, William L.; Gazarik, Michael J.

    2008-12-01

    The ultimate remote sensing benefits of the high resolution Infrared radiance spectrometers will be realized with their geostationary satellite implementation in the form of imaging spectrometers. This will enable dynamic features of the atmosphere's thermodynamic fields and pollutant and greenhouse gas constituents to be observed for revolutionary improvements in weather forecasts and more accurate air quality and climate predictions. As an important step toward realizing this application objective, the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) Engineering Demonstration Unit (EDU) was successfully developed under the NASA New Millennium Program, 2000-2006. The GIFTS-EDU instrument employs three focal plane arrays (FPAs), which gather measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The GIFTS calibration is achieved using internal blackbody calibration references at ambient (260 K) and hot (286 K) temperatures. In this paper, we introduce a refined calibration technique that utilizes Principle Component (PC) analysis to compensate for instrument distortions and artifacts, therefore, enhancing the absolute calibration accuracy. This method is applied to data collected during the GIFTS Ground Based Measurement (GBM) experiment, together with simultaneous observations by the accurately calibrated AERI (Atmospheric Emitted Radiance Interferometer), both simultaneously zenith viewing the sky through the same external scene mirror at ten-minute intervals throughout a cloudless day at Logan Utah on September 13, 2006. The accurately calibrated GIFTS radiances are produced using the first four PC scores in the GIFTS-AERI regression model. Temperature and moisture profiles retrieved from the PC-calibrated GIFTS radiances are verified against radiosonde measurements collected throughout the GIFTS sky measurement period. Using the GIFTS GBM calibration model, we compute the calibrated radiances from data

  9. Conjugate Observations of Optical Aurora with POLAR Satellite and Ground Based Imagers in Antarctica

    NASA Technical Reports Server (NTRS)

    Mende, S. H.; Frey, H.; Vo, H.; Geller, S. P.; Doolittle, J. H.; Spann, J. F., Jr.

    1998-01-01

    Operation of the ultraviolet imager on the POLAR satellite permits the observation of Aurora Borealis in daylight during northern summer. With optical imagers in the Automatic Geophysical Observatories (AGO-s) large regions of the oval of Aurora Australis can be observed simultaneously during the southern winter polar night. This opportunity permits conducting a systematic study of the properties of auroras on opposite ends of the same field line. It is expected that simultaneously observed conjugate auroras occurring on closed field lines should be similar to each other in appearance because of the close connection between the two hemispheres through particle scattering and mirroring processes. On open or greatly distorted field lines there is no a priori expectation of similarity between conjugate auroras. To investigate the influence of different IMF conditions on auroral behavior we have examined conjugate data for periods of southward IMF. Sudden brightening and subsequent poleward expansions are observed to occur simultaneously in both hemispheres. The POLAR data show that sudden brightening are initiated at various local time regions. When the local time of this region is in the field of view of the AGO station network then corresponding brightening is also found to occur in the southern hemisphere. Large features such as substorm induced westward propagation and resulting auroral brightening seem to occur simultaneously on conjugate hemispheres. The widely different view scales make it difficult to make unique identification of individual auroral forms in the POLAR and in the ground based data but in a general sense the data is consistent with conjugate behavior.

  10. Configurable adaptive optical system for imaging of ground-based targets from space

    NASA Astrophysics Data System (ADS)

    McComas, Brian K.; Friedman, Edward J.; Hooker, R. Brian; Cermak, Michael A.

    2003-03-01

    Space-based, high resolution, Earth remote sensing systems, that employ large, flexible, lightweight primary mirrors, will require active wavefront correction, in the form of active and adaptive optics, to correct for thermally and vibrationally induced deformations in the optics. These remote sensing systems typically have a large field-of-view. Unlike the adaptive optics on ground-based astronomical telescopes, which have a negligible field-of-view, the adaptive optics on these space-based remote sensing systems will be required to correct the wavefront over the entire field-of-view, which can be several degrees. The error functions for astronomical adaptive optics have been developed for the narrow field-of-view correction of atmospheric turbulence and do not address the needs of wide field space-based systems. To address these needs, a new wide field adaptive optics theory and a new error function are developed. Modeling and experimental results demonstrate the validity of the wide field adaptive optics theory and new error function. This new error function, which is a new extension of conventional adaptive optics, lead to the development of three new types of imaging systems: wide field-of-view, selectable field-of-view, and steerable field-of-view. These new systems can have nearly diffraction-limited performance across the entire field-of-view or a narrow movable region of high-resolution imaging. The factors limiting system performance will be shown. The range of applicability of the wide field adaptive optics theory is shown. The range of applicability is used to avoid limitations in system performance and to estimate the optical systems parameters, which will meet the system"s performance requirements.

  11. Conjugate Observations of Optical Aurora with POLAR Satellite and Ground Based Imagers in Antarctica

    NASA Technical Reports Server (NTRS)

    Mende, S. H.; Frey, H.; Vo, H.; Geller, S. P.; Doolittle, J. H.; Spann, J. F., Jr.

    1998-01-01

    Operation of the ultraviolet imager on the POLAR satellite permits the observation of Aurora Borealis in daylight during northern summer. With optical imagers in the Automatic Geophysical Observatories (AGO-s) large regions of the oval of Aurora Australis can be observed simultaneously during the southern winter polar night. This opportunity permits conducting a systematic study of the properties of auroras on opposite ends of the same field line. It is expected that simultaneously observed conjugate auroras occurring on closed field lines should be similar to each other in appearance because of the close connection between the two hemispheres through particle scattering and mirroring processes. On open or greatly distorted field lines there is no a priori expectation of similarity between conjugate auroras. To investigate the influence of different IMF conditions on auroral behavior we have examined conjugate data for periods of southward IMF. Sudden brightening and subsequent poleward expansions are observed to occur simultaneously in both hemispheres. The POLAR data show that sudden brightening are initiated at various local time regions. When the local time of this region is in the field of view of the AGO station network then corresponding brightening is also found to occur in the southern hemisphere. Large features such as substorm induced westward propagation and resulting auroral brightening seem to occur simultaneously on conjugate hemispheres. The widely different view scales make it difficult to make unique identification of individual auroral forms in the POLAR and in the ground based data but in a general sense the data is consistent with conjugate behavior.

  12. Evaluation of the operating range for ground-based infrared imaging tracking system

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Zhang, Zhen-duo; Zhang, Shu-mei

    2011-08-01

    Ground-based infrared imaging tracking system (GIITS) is of great importance for aerial target warning and guard. The operating range is one of the key performance specifications, which should be calculated, analyzed and studied during the whole GIITS design process. The operating range is mostly influenced by a few factors, including atmospheric attenuation, the performance of GIITS and feature of target and background. This paper firstly makes analysis and summarization on the definite localizations of the traditional operating range equation of the GIITS. The localizations are mainly in two aspects. On one hand, the dispersion of the image and the effect of image dispersion are not considered in the traditional method; on the other, calculate the radiation power received on the detector in order to analysis whether the output signal meets the detection requirements or not, without considering the effect of the background radiation. By improving of the traditional method, a new operating range calculation model of the GIITS was established based on two requirements. One is that the image size of observed target should meet the requirement of the processor signal extraction. The number of the pixel occupied by target image should be more than 9. The other is that the signal noise ratio (SNR) of the GIITS should not be less than 5 to meet the requirements of the target detection probability and spatial frequency. The SNR calculation equation in form of energy is deduced and the radiation characteristic of the observed target and background are analyzed. When evaluate the operating range of the GIITS using the new method, we should successively calculate two operating range values according to two requirements mentioned above and choose the minimum value as the analytic result. In the end, an evaluation of operating range for fighter aircraft is accomplished as an example. The influence factors in every aspect on operating range were explored by the calculated

  13. A Prototype Digital Image Management System

    PubMed Central

    Dwyer, Samuel J.; Templeton, Arch W.; Anderson, William H.; Tarlton, Mark A.; Hensley, Kenneth S.; Lee, Kyo Rak; Batnitzky, Solomon; Rosenthal, Stanton J.; Johnson, Joy A.; Preston, David F.

    1983-01-01

    A prototype digital image management system has been designed, implemented and is being evaluated by our department. The system satisfies two major requirements: (a) an on-line access, rapid response microcomputer network providing 9 day archiving of digital data; (b) a long-term, low demand archiving system. This paper provides an estimate of the cost of the system, the potential cost-savings, and identifies the digital data throughput using the Ethernet communications protocol. ImagesFigure 4

  14. Ground-Based Remote Sensing of Water-Stressed Crops: Thermal and Multispectral Imaging

    USDA-ARS?s Scientific Manuscript database

    Ground-based methods of remote sensing can be used as ground-truthing for satellite-based remote sensing, and in some cases may be a more affordable means of obtaining such data. Plant canopy temperature has been used to indicate and quantify plant water stress. A field research study was conducted ...

  15. Ground-based thermal and multispectral imaging of limited irrigation crops

    USDA-ARS?s Scientific Manuscript database

    Ground-based methods of remote sensing can be used as ground-truth for satellite-based remote sensing, and in some cases may be a more affordable means of obtaining such data. Plant canopy temperature has been used to indicate and quantify plant water stress. A field research study was conducted in ...

  16. A high-performance ground-based prototype of horn-type sequential vegetable production facility for life support system in space

    NASA Astrophysics Data System (ADS)

    Fu, Yuming; Liu, Hui; Shao, Lingzhi; Wang, Minjuan; Berkovich, Yu A.; Erokhin, A. N.; Liu, Hong

    2013-07-01

    Vegetable cultivation plays a crucial role in dietary supplements and psychosocial benefits of the crew during manned space flight. Here we developed a ground-based prototype of horn-type sequential vegetable production facility, named Horn-type Producer (HTP), which was capable of simulating the microgravity effect and the continuous cultivation of leaf-vegetables on root modules. The growth chamber of the facility had a volume of 0.12 m3, characterized by a three-stage space expansion with plant growth. The planting surface of 0.154 m2 was comprised of six ring-shaped root modules with a fibrous ion-exchange resin substrate. Root modules were fastened to a central porous tube supplying water, and moved forward with plant growth. The total illuminated crop area of 0.567 m2 was provided by a combination of red and white light emitting diodes on the internal surfaces. In tests with a 24-h photoperiod, the productivity of the HTP at 0.3 kW for lettuce achieved 254.3 g eatable biomass per week. Long-term operation of the HTP did not alter vegetable nutrition composition to any great extent. Furthermore, the efficiency of the HTP, based on the Q-criterion, was 7 × 10-4 g2 m-3 J-1. These results show that the HTP exhibited high productivity, stable quality, and good efficiency in the process of planting lettuce, indicative of an interesting design for space vegetable production.

  17. Images of Neptune's ring arcs obtained by a ground-based telescope

    NASA Astrophysics Data System (ADS)

    Sicardy, B.; Roddier, F.; Roddier, C.; Perozzi, E.; Graves, J. E.; Guyon, O.; Northcott, M. J.

    1999-08-01

    Neptune has a collection of incomplete narrow rings, known as ring arcs, which should in isolation be destroyed by differential motion in a matter of months. Yet since first discovered by stellar occultations in 1984, they appear to have persisted, perhaps through a gravitational resonance effect involving the satellite Galatea. Here we report ground-based observations of the ring arcs, obtained using an adaptive optics system. Our data, and those obtained using the Hubble Space Telescope (reported in a companion paper), indicate that the ring arcs are near, but not within the resonance with Galatea, in contrast to what is predicted by some models.

  18. Fast and optimal multiframe blind deconvolution algorithm for high-resolution ground-based imaging of space objects.

    PubMed

    Matson, Charles L; Borelli, Kathy; Jefferies, Stuart; Beckner, Charles C; Hege, E Keith; Lloyd-Hart, Michael

    2009-01-01

    We report a multiframe blind deconvolution algorithm that we have developed for imaging through the atmosphere. The algorithm has been parallelized to a significant degree for execution on high-performance computers, with an emphasis on distributed-memory systems so that it can be hosted on commodity clusters. As a result, image restorations can be obtained in seconds to minutes. We have compared and quantified the quality of its image restorations relative to the associated Cramér-Rao lower bounds (when they can be calculated). We describe the algorithm and its parallelization in detail, demonstrate the scalability of its parallelization across distributed-memory computer nodes, discuss the results of comparing sample variances of its output to the associated Cramér-Rao lower bounds, and present image restorations obtained by using data collected with ground-based telescopes.

  19. GravityCam: ground-based wide-field high-resolution imaging and high-speed photometry

    NASA Astrophysics Data System (ADS)

    Dominik, Martin; Mackay, Craig; Steele, Iain; Snodgrass, Colin; Hirsch, Michael; Gråe Jørgensen, Uffe; Hundertmark, Markus; Rebolo, Rafael; Horne, Keith; Bridle, Sarah; Sicardy, Bruno; Bramich, Daniel; Alsubai, Khalid

    2015-12-01

    The image blurring by the Earth's atmosphere generally poses a substantial limitation to ground-based observations. While opportunities in space are scarce, lucky imaging can correct over a much larger patch of sky and with much fainter reference stars. We propose the first of a new kind of versatile instruments, "GravityCam", composed of ~100 EMCCDs, that will open up two entirely new windows to ground-based astronomy: (1) wide-field high-resolution imaging, and (2) wide-field high-speed photometry. Potential applications include (a) a gravitational microlensing survey going 4 magnitudes deeper than current efforts, and thereby gaining a factor 100 in mass at the same sensitivity, which means probing down to Lunar mass or even below, (b) extra-solar planet hunting via transits in galactic bulge fields, with high time resolution well-suited for transit timing variation studies, (c) variable stars in crowded fields, with sensitivity to very short periods, (d) asteroseismology with many bright stars in one pointing, (e) serendipitous occultations of stars by small solar system bodies, giving access to the small end of the Kuiper Belt size distribution and potentially leading to the first detection of true Oort cloud objects, while predicted occultations at high time resolution can reveal atmospheres, satellites, or rings, (f) general data mining of the high-speed variable sky (down to 40 ms cadence).

  20. A Comparison of Auroral In-Situ Rocket Electron Measurements and Ground-Based Multi-spectral EMCCD Imaging

    NASA Astrophysics Data System (ADS)

    Grubbs, G. A., II; Samara, M.; Michell, R.; Hampton, D.; Hecht, J. H.

    2015-12-01

    The Ground-to-Rocket Electrodynamics-Electrons Correlative Experiment (GREECE) mission successfully launched from Poker Flat, Alaska on 03 March 2014 at 11:09:50 UT and reached an apogee of approximately 335 km during a luminous auroral event. Multiple ground-based electron-multiplying charge-coupled device (EMCCD) imagers were positioned at Venetie, Alaska and aimed along magnetic zenith in order to observe the brightness of different auroral emission lines (427.8, 557.7, and 844.6 nm with a 47 degree field of view) at the magnetic footpoint of the payload, near apogee. Emission line brightness data are presented at the footpoint of the rocket flight and compared with electron characteristics taken by the Acute Precipitating Electron Spectrometer (APES) on-board instrument. Ratios of different auroral emission lines are combined with previously published models in order to estimate the characteristic energy of the incident electron population, which is directly compared to the APES data for validation. Our goal is to describe the auroral emissions produced from a known precipitating electron distribution, such that we can more accurately use ground-based imaging and photometry to infer the characteristics of the precipitating electrons. These techniques can then be applied over larger scales and longer times, when only multi-spectral imaging data are available with no corresponding in situ data.

  1. Design of ground-based physical simulation system for satellite-borne TDI-CCD dynamic imaging

    NASA Astrophysics Data System (ADS)

    Sun, Zhiyuan; Zhang, Liu; Jin, Guang; Yang, Xiubin

    2010-11-01

    As we know, the existence of image motion has a bad effect on the image quality of satellite-borne TDI CCD camera. Although many theories on image motion are proposed to cope with this problem, few simulations are done to justify the proposed theories on ground. And thus, in this paper, a ground-based physical simulation system for TDI CCD imaging is developed and specified, which consists of a physical simulation subsystem for precise satellite attitude control based on a 3-axis air bearing table, and an imaging and simulation subsystem utilizing area-array CCD to simulate TDI CCD. The designed system could realize not only a precise simulation of satellite attitude control, whose point accuracy is above 0.1° and steady accuracy above 0.01°/s, but also an imaging simulation of 16-stage TDI CCD with 0.1s its integration time. This paper also gives a mathematical model of image motion of this system analogous with satellite-borne TDI CCD, and detailed descriptions on the principle utilizing area-array CCD to simulate TDI CCD. It is shown that experiment results are in accordance with mathematical simulation, and that the image quality deteriorate seriously when the correspondence between the image velocity and signal charges transfer velocity is broken out, which suggest not only the validity of the system design but also the validity of the proposed image motion theory of TDI CCD.

  2. Study of Upper Albian rudist buildups in the Edwards Formation using ground-based hyperspectral imaging and terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Krupnik, Diana; Khan, Shuhab; Okyay, Unal; Hartzell, Preston; Zhou, Hua-Wei

    2016-11-01

    Ground-based hyperspectral imaging is used for development of digital outcrop models which can facilitate detailed qualitative and quantitative sedimentological analysis and augment the study of depositional environment, diagenetic processes, and hydrocarbon reservoir characterization in areas which are physically inaccessible. For this investigation, ground-based hyperspectral imaging is combined with terrestrial laser scanning to produce mineralogical maps of Late Albian rudist buildups of the Edwards formation in the Lake Georgetown Spillway in Williamson County, Texas. The Edwards Formation consists of shallow water deposits of reef and associated interreef facies. It is an aquifer in western Texas and was investigated as a hydrocarbon play in south Texas. Hyperspectral data were registered to a geometrically accurate laser point cloud-generated mesh with sub-pixel accuracy and were used to map compositional variation by distinguishing spectral properties unique to each material. More calcitic flat-topped toucasid-rich bioherm facies were distinguished from overlying porous sucrosic dolostones, and peloid wackestones and packstones of back-reef facies. Ground truth was established by petrographic study of samples from this area. This research integrates high-resolution datasets to analyze geometrical and compositional properties of this carbonate formation at a finer scale than traditional methods have achieved and to model the geometry and composition of rudist buildups.

  3. Ionospheric currents estimated simultaneously from CHAMP satelliteand IMAGE ground-based magnetic field measurements: a statisticalstudy at auroral latitudes

    NASA Astrophysics Data System (ADS)

    Ritter, P.; Lühr, H.; Viljanen, A.; Amm, O.; Pulkkinen, A.; Sillanpää, I.

    2004-02-01

    . One important contribution to the magnetic field measured at satellite altitude and at ground level comes from the external currents. We used the total field data sampled by the Overhauser Magnetometer on CHAMP and the horizontal magnetic field measurements of the IMAGE ground-based magnetometer network to study the ionospheric Hall current system in the auroral regions. For the CHAMP data a current model consisting of a series of lines and placed at a height of 110km is fitted to the magnetic field signature sampled on the passage across the polar region. The derived current distributions depend, among others, on season and on the local time of the satellite track. At dawn/dusk the auroral electrojets can be detected most clearly in the auroral regions. Their intensity and location are evidently correlated with the activity index. For a period of almost two years the results obtained from space and the currents determined from ground-based observations are studied. For the full IMAGE station array a newly-developed method of spherical elementary current systems (SECS) is employed to compute the 2-D equivalent current distribution, which gives a detailed picture of an area covering latitudes N and E in the auroral region. Generally, the current estimates from satellite and ground are in good agreement. The results of this survey clearly show the average dependence of the auroral electrojet on season and local time. This is particularly true during periods of increased auroral activity. The correlation coefficient of the results is close to one in the region of sizeable ionospheric current densities. Also the ratio of the current densities, as determined from above and below the ionosphere, is close to unity. It is the first time that the method of Hall current estimate from a satellite has been validated quantitatively by ground-based observations. Among others, this result is of interest for magnetic main field modelling, since it demonstrates that ground-based

  4. Three-dimensional tomographic reconstruction of mesospheric airglow structures using two-station ground-based image measurements.

    PubMed

    Hart, Vern P; Doyle, Timothy E; Taylor, Michael J; Carruth, Brent L; Pautet, Pierre-Dominique; Zhao, Yucheng

    2012-03-01

    A new methodology is presented to create two-dimensional (2D) and three-dimensional (3D) tomographic reconstructions of mesospheric airglow layer structure using two-station all-sky image measurements. A fanning technique is presented that produces a series of cross-sectional 2D reconstructions, which are combined to create a 3D mapping of the airglow volume. The imaging configuration is discussed and the inherent challenges of using limited-angle data in tomographic reconstructions have been analyzed using artificially generated imaging objects. An iterative reconstruction method, the partially constrained algebraic reconstruction technique (PCART), was used in conjunction with a priori information of the airglow emission profile to constrain the height of the imaged region, thereby reducing the indeterminacy of the inverse problem. Synthetic projection data were acquired from the imaging objects and the forward problem to validate the tomographic method and to demonstrate the ability of this technique to accurately reconstruct information using only two ground-based sites. Reconstructions of the OH airglow layer were created using data recorded by all-sky CCD cameras located at Bear Lake Observatory, Utah, and at Star Valley, Wyoming, with an optimal site separation of ~100 km. The ability to extend powerful 2D and 3D tomographic methods to two-station ground-based measurements offers obvious practical advantages for new measurement programs. The importance and applications of mesospheric tomographic reconstructions in airglow studies, as well as the need for future measurements and continued development of techniques of this type, are discussed. © 2012 Optical Society of America

  5. Modeling SSI Variations using Ground-Based Images from the San Fernando Observatory

    NASA Astrophysics Data System (ADS)

    Chapman, G. A.; Choudhary, D. P.

    2015-12-01

    Full-Disk photometric images are obtained on a daily basis at the San Fernando Observatory. The images are at wavelengths of 672, 472, and 393 nm. From these images, relative irradiance indices are calculated and compared with SSI variations at selected wavelengths. We will present results of modeling spacecraft SSI variations with our indices.

  6. convolve_image.pro: Common-Resolution Convolution Kernels for Space- and Ground-Based Telescopes

    NASA Astrophysics Data System (ADS)

    Aniano, Gonzalo J.

    2014-01-01

    The IDL package convolve_image.pro transforms images between different instrumental point spread functions (PSFs). It can load an image file and corresponding kernel and return the convolved image, thus preserving the colors of the astronomical sources. Convolution kernels are available for images from Spitzer (IRAC MIPS), Herschel (PACS SPIRE), GALEX (FUV NUV), WISE (W1 - W4), Optical PSFs (multi- Gaussian and Moffat functions), and Gaussian PSFs; they allow the study of the Spectral Energy Distribution (SED) of extended objects and preserve the characteristic SED in each pixel.

  7. Real Time Detection Of Anomalous Satellite Behavior from Ground-Based Telescope Images

    DTIC Science & Technology

    2007-11-02

    for image distortion 19 9. Distortion affected by each OTF 20 10. OTF normalized weighting energies 21 11. Selected OTF contour plots 21 12...Normalized energy of sample random OTFs from data set 7 plotted against time. Time is represented by temporally spaced images 1 through 20 22 13. Selected...block feature extraction 27 16. Fourier space wedge feature extraction with example wedge energy sums depicted. 29 17. Real image gray scale to binary

  8. Millimeter-wave Ground-based Synthetic Aperture Radar Imaging for Foreign Object Debris Detection: Experimental Studies at Short Ranges

    NASA Astrophysics Data System (ADS)

    Yigit, Enes; Demirci, Sevket; Unal, Atilla; Ozdemir, Caner; Vertiy, Alexey

    2012-12-01

    In this paper, millimeter-wave imaging of foreign object debris (FOD)-type objects on the ground is studied with the help of ground-based synthetic aperture radar (GB-SAR) technique. To test the feasibility of detecting runway FODs with this technique, some preliminary experiments are conducted within short antenna-to-target ranges of small imaging patches. An automated stripmap GB-SAR system with stepped-frequency transmission is constructed together with a quasi-monostatic data collection operation. The imaging experiments for various braces and screws are then carried out by using 32- 36 GHz and 90- 95 GHz frequency bands of the millimeter-wave. Images reconstructed by a matched-filter based algorithm are analyzed to determine the proper system parameters for an efficient imaging and to comprehend the factors against a successful detection. Results demonstrate the capability of GB-SAR imaging in accurately locating these FOD-like targets under near-range operating conditions.

  9. High Resolution Imaging of Satellites with Ground-Based 10-m Astronomical Telescopes

    SciTech Connect

    Marois, C

    2007-01-04

    High resolution imaging of artificial satellites can play an important role in current and future space endeavors. One such use is acquiring detailed images that can be used to identify or confirm damage and aid repair plans. It is shown that a 10-m astronomical telescope equipped with an adaptive optics system (AO) to correct for atmospheric turbulence using a natural guide star can acquire high resolution images of satellites in low-orbits using a fast shutter and a near-infrared camera even if the telescope is not capable of tracking satellites. With the telescope pointing towards the satellite projected orbit and less than 30 arcsec away from a guide star, multiple images of the satellite are acquired on the detector using the fast shutter. Images can then be shifted and coadded by post processing to increase the satellite signal to noise ratio. Using the Keck telescope typical Strehl ratio and anisoplanatism angle as well as a simple diffusion/reflection model for a satellite 400 km away observed near Zenith at sunset or sunrise, it is expected that such system will produced > 10{sigma} K-band images at a resolution of 10 cm inside a 60 arcsec diameter field of view. If implemented, such camera could deliver the highest resolution satellite images ever acquired from the ground.

  10. Toward the Ground-based Imaging of Satellites at Geosynchronous Altitude

    NASA Astrophysics Data System (ADS)

    Mozurkewich, D.; Armstrong, J.; Hindsley, R.; Jorgensen, A.; Restaino, S.; Schmitt, H.

    2011-09-01

    To image satellites at geosynchronous altitude requires a telescope aperture of 50 to 200 meters, depending on the choice of wavelength and required resolution. Building such a facility is an expensive, lengthy undertaking and is probably a couple of decades away. Interferometry has been proposed as an alternative and although it looks promising on paper, so far it has failed to deliver. In the astronomical community, aperture masking - an interferometric imaging techniques - consistently produces higher-quality images than a camera with adaptive-optics. Sadly, separated-aperture interferometry lags further behind but their image quality is improving as the number of apertures increases. A bigger problem is poor sensitivity. We understand the light loss-issues and can increase the sensitivity by mitigating these problems and by using larger telescopes with adaptive optics. In this paper, we argue for a design consisting of 30 identical telescopes mounted on a steerable boom. The telescopes feed optical fibers which in turn feed the beam combiner. We present optical and mechanical designs along with a sensitivity analysis. We discuss the applicability of this system to imaging satellites.

  11. Use of Satellite and Ground-based Digital Images to Detect and Monitor Dust Storms in the Mojave Desert

    NASA Astrophysics Data System (ADS)

    Chavez, P. S.; MacKinnon, D. J.; Reynolds, R. L.; Velasco, M. G.

    2002-12-01

    Wind-induced dust emission from sources in the southwestern United States is not a major contributor to global dust flux, but it is important on a regional and national scale because of its effects on air quality, human health and safety, as well as ecosystem dynamics. Integrated remotely sensed satellite, airborne, and ground-based image data have strong potential to detect and monitor active dust storms and map areas vulnerable to wind erosion in the Southwest. Since 1999, high temporal resolution digital images collected by satellite and a ground-based, automated digital camera station have been used to detect, monitor, and analyze the location, size, frequency, duration, and transport patterns of large dust storms in the central Mojave Desert. One of the biggest dust storms of this past decade occurred on April 15, 2002, when at least several million metric tons of dust were emitted from the central Mojave Desert alone. During this storm, geostationary satellite (GOES) images documented the arrival of two very large dust plumes into the Las Vegas Valley, NV, one from a valley about 40 km to the west and the other from a heavily used area about 170 km to the southwest. Large, rapid increases in levels of PM10 (particulate matter less than 10 micrometers) in the Las Vegas area corresponded with the arrival of these plumes, with PM10 values increasing from a range of approximately 100 to 250 micrograms/m3 to 1,100 to 1,500 micrograms/m3 within 30 minutes. Satellite imaging systems currently available cannot detect and monitor dust storms of the size typically generated in the Southwest on an operational basis or be used to produce models for emission-rate predictions. The satellite imaging system on GOES is the only one available having adequate temporal resolution to detect and monitor active dust storms on a routine basis; however, it can only detect very large dust storms because its spatial and spectral resolutions are very low. A satellite imaging system with

  12. Direct imaging of planetary systems with a ground-based radio telescope array

    NASA Technical Reports Server (NTRS)

    Jones, Dayton L.

    1994-01-01

    The National Radio Astronomy Observatory's proposed Millimeter Array (MMA) will bring unprecedented sensitivity, angular resolution, and image dynamic range to the millimeter wavelength region of the spectrum. An obvious question is whether such an instrument could be used to detect planets orbiting nearby stars. The techniques of aperture synthesis imaging developed for centimeter wavelength radio arrays are capable of producing images whose dynamic ranges greatly exceed the brightness ratio of a solar-type star and a Jupiter-like planet at sub-millimeter or millimeter wavelengths. The angular resolution required to separate a star and planet at a few pc distance can be obtained with baselines of several km. The greatest challenge is sensitivity. At the highest possible observing frequencies (approximately 300 GHz for typical high, dry sites, and approximately 900 GHz from the Antarctic plateau), the proposed MMA will be unable to detect the thermal emission from a Jupiter-like planet a few pc away. An upgraded MMA operating near 300 GHz with twice the currently proposed number of antennas, a 20% fractional bandwidth, and improved receivers could detect Jupiter at 4 pc in a few months. Building such an array on the Antarctic plateau and operating at approximately 900 GHz would allow Jupiter at 4 pc to be detected in approximately one day of observing time.

  13. Direct imaging of planetary systems with a ground-based radio telescope array

    NASA Technical Reports Server (NTRS)

    Jones, Dayton L.

    1994-01-01

    The National Radio Astronomy Observatory's proposed Millimeter Array (MMA) will bring unprecedented sensitivity, angular resolution, and image dynamic range to the millimeter wavelength region of the spectrum. An obvious question is whether such an instrument could be used to detect planets orbiting nearby stars. The techniques of aperture synthesis imaging developed for centimeter wavelength radio arrays are capable of producing images whose dynamic ranges greatly exceed the brightness ratio of a solar-type star and a Jupiter-like planet at sub-millimeter or millimeter wavelengths. The angular resolution required to separate a star and planet at a few pc distance can be obtained with baselines of several km. The greatest challenge is sensitivity. At the highest possible observing frequencies (approximately 300 GHz for typical high, dry sites, and approximately 900 GHz from the Antarctic plateau), the proposed MMA will be unable to detect the thermal emission from a Jupiter-like planet a few pc away. An upgraded MMA operating near 300 GHz with twice the currently proposed number of antennas, a 20% fractional bandwidth, and improved receivers could detect Jupiter at 4 pc in a few months. Building such an array on the Antarctic plateau and operating at approximately 900 GHz would allow Jupiter at 4 pc to be detected in approximately one day of observing time.

  14. Implications of Ground Based Photometric Images for Long Term Solar Irradiance Variations

    NASA Astrophysics Data System (ADS)

    Walton, S. R.; Preminger, D. G.; Chapman, G. A.

    2004-12-01

    The San Fernando Observatory (SFO) has produced photometric full disk solar images at 5 arc second resolution since 1986, and 2.5 arc second resolution since 1989. We have previously shown that the best quantities for solar irradiance modeling are the photometric sums Σ , defined as the summed residual intensity on these photometric images. In particular, a linear regression of total solar irradiance S to the time series of Σ r and Σ K, the photometric sums in broadband red and Ca~II~K filters, respectively, does an excellent job of reproducing S during cycle 22 (Preminger, Walton, and Chapman 2002, JGR 107, Issue A11, SSH 6-1). We have also shown (Walton, Preminger and Chapman 2003, Solar Phys. 213, 301) that variations in the chromospheric network appear to account for no more than 25% of the change in S over the solar cycle. In this talk, we extend these results to cycle 23 and discuss their implication for long term changes in S. In particular, if Σ r = Σ K = 0 can be taken as representing the complete absence of solar activity, then one would conclude that the minimum level of S is not much below those currently observed at solar minimum; quantitatively, about 0.3 W~m2 below that level.

  15. Ground-based thermal imaging of lava lakes at Erebus volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Calkins, J.; Oppenheimer, C.; Kyle, P. R.

    2008-11-01

    Mount Erebus, a large intraplate stratovolcano dominating Ross Island, Antarctica, hosts the world's only active phonolite lava lakes. The main manifestation of activity at Erebus volcano in December 2004 was as the presence of two convecting lava lakes within an inner crater. The long-lived Ray Lake, ~ 1400 m 2 in area, was the site of up to 10 small Strombolian eruptions per day. A new but short-lived, ~ 1000-1200 m 2 lake formed at Werner vent in December 2004 sourced by lava flowing from a crater formed in 1993 by a phreatic eruption. We measured the radiative heat flux from the two lakes in December 2004 using a compact infrared (IR) imaging camera. Daily thermal IR surveys from the Main Crater rim provide images of the lava lake surface temperatures and identify sites of upwelling and downwelling. The radiative heat outputs calculated for the Ray and Werner Lakes are 30-35 MW and 20 MW, respectively. We estimate that the magma flux needed to sustain the combined heat loss is ~ 250-710 kg s - 1 , that the minimum volume of the magma reservoir is 2 km 3, and that the radius of the conduit feeding the Ray lake is ~ 2 m.

  16. Mapping the bathymetry of a turbid, sand-bed river using ground-based reflectance measurements and hyperspectral image data

    NASA Astrophysics Data System (ADS)

    Legleiter, C. J.; Kinzel, P. J.; Nelson, J. M.

    2010-12-01

    The Platte River in central Nebraska encompasses relatively stable, single-thread to island-braided reaches as well as wider, fully braided segments with highly mobile bar forms. Across this range of morphologies, suspended sediment and organic material contribute to turbid water conditions. In addition, the Platte is the focus of management activities intended to mitigate encroachment of vegetation and improve habitat for various migratory bird species, primarily by increasing the areal extent of shallow to slightly emergent mid-channel sand bars. The diversity of channel types and optical properties make this a challenging environment in which to implement a remote sensing approach, but the Platte also provides an opportunity for these methods to support management objectives. To evaluate the potential utility of remote sensing techniques along the Platte, we acquired hyperspectral image data, collected field spectra, and surveyed bed topography for three reaches. Ground-based measurements of reflectance Rλ were made above the water surface for flow depths d from 5 - 67 cm and a range of substrate types. An optimal band ratio analysis (OBRA) of these data, whereby regressions of log-transformed band ratios against measured depths were performed for all possible band combinations, yielded a strong, linear relationship (R2 = 0.95) between ln ({R593}/{R{647}) and d. Similar band ratio analyses were performed using reflectance spectra extracted from the hyperspectral image data for locations at which bed elevations were surveyed and compared to measured water surface elevations to calculate flow depths. Image-based OBRA produced variable results for the three sites. For a narrower, deeper reach lacking mobile mid-channel bars, a ln ({R490}/{R{638}) vs. d relation had an R2 of 0.83; applying this expression to the image generated a bathymetric map that agreed closely with our survey data. The other two sites featured fully braided morphologies, shallower depths, and

  17. Ground-based Hyperspectral Imaging for Fluid-related Diagenetic Heterogeneities and Fluid-flow Pathways in the Wingate Sandstone

    NASA Astrophysics Data System (ADS)

    Okyay, U.; Khan, S.

    2015-12-01

    The Jurassic Wingate Sandstone show prominent color variations throughout southeastern Utah due to diagenetic changes. The characteristic diagenetic changes suggest fluid-rock interactions through the sandstone. Distinctive spectral signatures of diagenetic minerals can be used to map diagenetic heterogeneities and possibly fluid-flow pathways. The main objective of this work was to identify characteristic diagenetic minerals, and map their spatial variability at outcrop scale in Wingate Sandstone exposures of Lisbon Valley, Utah. Laboratory reflectance spectroscopy analysis of the samples facilitated identification of diagnostic spectral characteristics of the common diagenetic minerals and their relative abundances between altered and unaltered Wingate Sandstone. Comparisons of reflectance spectroscopy with ground-based imaging spectroscopy data provided a method for mapping fluid-related diagenetic heterogeneities and fluid-flow pathways in near vertical rock faces of steep outcrops. Additionally, ASTER satellite and HyMap airborne data helped evaluating spatial variations of diagenetic mineral at a broader scale in plan-view. The ground-based hyperspectral data demonstrated the ability to identify and map mineral assemblages with two-dimensional lateral continuity on near-vertical rock faces. The bleached and unbleached areas are alternating throughout the vertical face of the outcrop. The relative hematite abundance observed in the unbleached areas in the vertical section are somewhat symmetrical. This indicates fairly similar reaction intensities along the upper and lower reaction fronts observed in the vertical section. The distribution geometry and relative abundances of diagenetic minerals not only suggest multiple paths of fluid-flow in Wingate Sandstone but also provides some insight about relative direction of past fluid-flow.

  18. Ground-Based Measurement Experiment and First Results with Geosynchronous-Imaging Fourier Transform Spectrometer Engineering Demonstration Unit

    NASA Technical Reports Server (NTRS)

    Zhou, Daniel K.; Smith, William L.; Bingham, Gail E.; Huppi, Ronald J.; Revercomb, Henry E.; Zollinger, Lori J.; Larar, Allen M.; Liu, Xu; Tansock, Joseph J.; Reisse, Robert A.; hide

    2007-01-01

    The geosynchronous-imaging Fourier transform spectrometer (GIFTS) engineering demonstration unit (EDU) is an imaging infrared spectrometer designed for atmospheric soundings. It measures the infrared spectrum in two spectral bands (14.6 to 8.8 microns, 6.0 to 4.4 microns) using two 128 x 128 detector arrays with a spectral resolution of 0.57 cm(exp -1) with a scan duration of approximately 11 seconds. From a geosynchronous orbit, the instrument will have the capability of taking successive measurements of such data to scan desired regions of the globe, from which atmospheric status, cloud parameters, wind field profiles, and other derived products can be retrieved. The GIFTS EDU provides a flexible and accurate testbed for the new challenges of the emerging hyperspectral era. The EDU ground-based measurement experiment, held in Logan, Utah during September 2006, demonstrated its extensive capabilities and potential for geosynchronous and other applications (e.g., Earth observing environmental measurements). This paper addresses the experiment objectives and overall performance of the sensor system with a focus on the GIFTS EDU imaging capability and proof of the GIFTS measurement concept.

  19. High-Contrast Imaging of Epsilon Eridani with Ground-Based Instruments

    NASA Technical Reports Server (NTRS)

    Mizuki, T.; Yamada, T.; Carson, J. C.; Kuzuhara, M.; Nakagawa, T.; Nishikawa, J.; Sitko, M. L.; Kudo, T.; Kusakabe, N.; Hashimoto, J.; hide

    2016-01-01

    Epsilon Eridani is one of the nearest solar-type stars. Its proximity and relatively young age allow high-contrast imaging observations to achieve sensitivities to planets at narrow separations down to an inner radius of approximately 5 AU. Previous observational studies of the system report a dust disk with asymmetric morphology as well as a giant planet with large orbital eccentricity, which may require another massive companion to induce the peculiar morphology and to enhance the large orbital eccentricity. In this paper, we report results from deep high-contrast imaging observations to detect the previously reported planet and search for other unseen less massive companions with Subaru/HiCIAO, Gemini-South/NICI, and VLT/NACO. No positive detection was made, but high-contrast measurements with the CH4S narrow-band filter of HiCIAO achieved sensitivities at 14.7 mag differential magnitude level, at an angular separation of 1.0''. In terms of planetary mass, as determined by cooling evolutionary models, the highest sensitivities were achieved by the Lp broad-band filter of NACO, resulting in sensitivities corresponding to 1.8, 2.8, and 4.5 M(sub jup) at the projected separation of 3 AU, if 200, 400, and 800 Myr is assumed for the age of the system, respectively. We also discuss origins of the dust disk from the detection sensitivity in the planetary mass and find that a less massive eccentric planet is preferred for disk stirring, which is consistent with the orbital parameters of epsilon Eri b claimed from the previous long-term radial velocity monitoring.

  20. Predicting Electron Energy Flux Using Ground-Based Multi-Spectral Auroral Imaging

    NASA Astrophysics Data System (ADS)

    Grubbs, G. A.; Samara, M.; Michell, R.; Redmon, R. J.

    2013-12-01

    High-resolution, multi-spectral auroral observations can now be routinely acquired using the Multi-spectral Observatory Of Sensitive EMCCDs (MOOSE), currently installed in Poker Flat, AK. Observations from the past 2 auroral seasons have yielded many simultaneous auroral observations in 4 different emission lines (427.8 nm, 557.7 nm, 630 nm, and 844.6 nm). From these data, the brightness of the absolute auroral emissions will be calculated. Combined with atmospheric modeling, auroral emission brightness will be used to predict the total energy flux and characteristic energy of the electrons responsible for the aurora. The theory behind this method is only developed for auroral measurements in the magnetic zenith, and therefore it is not known to what extent it can be applied off zenith. All-sky auroral image data will be examined and compared with DMSP satellite overpasses to quantify the extent to which the model can make predictions off-zenith, creating an empirical model that could then be applied to the many cases without overpasses. This will lead to large-scale 2-D maps of electron precipitation characteristics which can contribute to global ionospheric models.

  1. High-contrast imaging of ɛ Eridani with ground-based instruments

    NASA Astrophysics Data System (ADS)

    Mizuki, T.; Yamada, T.; Carson, J. C.; Kuzuhara, M.; Nakagawa, T.; Nishikawa, J.; Sitko, M. L.; Kudo, T.; Kusakabe, N.; Hashimoto, J.; Abe, L.; Brander, W.; Brandt, T. D.; Egner, S.; Feldt, M.; Goto, M.; Grady, C. A.; Guyon, O.; Hayano, Y.; Hayashi, M.; Hayashi, S. S.; Henning, T.; Hodapp, K. W.; Ishii, M.; Iye, M.; Janson, M.; Kandori, R.; Knapp, G. R.; Kwon, J.; Matsuo, T.; McElwain, M. W.; Miyama, S.; Morino, J.; Moro-Martin, A.; Nishimura, T.; Pyo, T.; Serabyn, E.; Suenaga, T.; Suto, H.; Suzuki, R.; Takahashi, Y. H.; Takami, M.; Takato, N.; Terada, H.; Thalmann, C.; Turner, E. L.; Watanabe, M.; Wisniewski, J.; Takami, H.; Usuda, T.; Tamura, M.

    2016-11-01

    ɛ Eridani is one of the nearest solar-type stars. Its proximity and relatively young age allow high-contrast imaging observations to achieve sensitivities to planets at narrow separations down to an inner radius of 5 AU. Previous observational studies of the system report a dust disk with asymmetric morphology as well as a giant planet with large orbital eccentricity, which may require another massive companion to induce the peculiar morphology and to enhance the large orbital eccentricity. In this paper, we report results from deep high-contrastimaging observations to detect the previously reported planet and search for other unseen less massive companions with Subaru/HiCIAO, Gemini-South/NICI, and VLT/NACO. No positive detection was made, but high-contrast measurements with the CH4S narrow-band filter of HiCIAO achieved sensitivities at 14.7 mag differential magnitude level, at an angular separation of 1.0″. In terms of planetary mass, as determined by cooling evolutionary models, the highest sensitivities were achieved by the Lp broad-band filter of NACO, resulting in sensitivities corresponding to 1.8, 2.8, and 4.5 Mjup at the projected separation of 3 AU, if 200, 400, and 800 Myr is assumed for the age of the system, respectively. We also discuss origins of the dust disk from the detection sensitivity in the planetary mass and find that a less massive eccentric planet is preferred for disk stirring, which is consistent with the orbital parameters of ɛ Eri b claimed from the previous long-term radial velocity monitoring.

  2. High-resolution image reconstruction technique applied to the optical testing of ground-based astronomical telescopes

    NASA Astrophysics Data System (ADS)

    Jin, Zhenyu; Lin, Jing; Liu, Zhong

    2008-07-01

    By study of the classical testing techniques (such as Shack-Hartmann Wave-front Sensor) adopted in testing the aberration of ground-based astronomical optical telescopes, we bring forward two testing methods on the foundation of high-resolution image reconstruction technology. One is based on the averaged short-exposure OTF and the other is based on the Speckle Interferometric OTF by Antoine Labeyrie. Researches made by J.Ohtsubo, F. Roddier, Richard Barakat and J.-Y. ZHANG indicated that the SITF statistical results would be affected by the telescope optical aberrations, which means the SITF statistical results is a function of optical system aberration and the atmospheric Fried parameter (seeing). Telescope diffraction-limited information can be got through two statistics methods of abundant speckle images: by the first method, we can extract the low frequency information such as the full width at half maximum (FWHM) of the telescope PSF to estimate the optical quality; by the second method, we can get a more precise description of the telescope PSF with high frequency information. We will apply the two testing methods to the 2.4m optical telescope of the GMG Observatory, in china to validate their repeatability and correctness and compare the testing results with that of the Shack-Hartmann Wave-Front Sensor got. This part will be described in detail in our paper.

  3. Spectral invariance hypothesis study of polarized reflectance with Ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI)

    NASA Astrophysics Data System (ADS)

    Bradley, Christine L.; Kupinski, Meredith; Diner, David J.; Xu, Feng; Chipman, Russell A.

    2015-09-01

    Many models used to represent the boundary condition for the separation of atmospheric scattering from the surface reflectance in polarized remote sensing measurements assume that the polarized surface reflectance is spectrally neutral. The Spectral Invariance Hypothesis asserts that the magnitude and shape of the polarized bidirectional reflectance factor (pBRF) is equal for all wavelengths. In order to test this hypothesis, JPL's Ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI) is used to measure polarization information of different outdoor surface types. GroundMSPI measures the linear polarization Stokes parameters (I, Q, U), at three wavelengths, 470 nm, 660 nm, and 865 nm. The camera is mounted on a two-axis gimbal to accurately select the view azimuth and elevation directions. On clear sky days we acquired day-long scans of scenes that contain various surface types such as grass, dirt, cement, brick, and asphalt and placed a Spectralon panel in the camera field of view to provide a reflectance reference. Over the course of each day, changing solar position in the sky provides a large range of scattering angles for this study. The polarized bidirectional reflectance factor (pBRF) is measured for the three wavelengths and the best fit slope of the spectral correlation is reported. This work reports the range of best fit slopes measured for five region types.

  4. A CMOS visible silicon imager hybridized to a Rockwell 2RG multiplexer as a new detector for ground based astronomy

    NASA Astrophysics Data System (ADS)

    Dorn, Reinhold J.; Eschbaumer, Siegfried; Finger, Gert; Mehrgan, Leander; Meyer, Manfred; Stegmeier, Joerg

    2006-06-01

    For the past 25 years Charge Coupled Devices (CCDs) have been used as the preferred detector for ground based astronomy to detect visible photons. As an alternative to CCDs, silicon-based hybrid CMOS focal plane array technology is evolving rapidly. Visible hybrid detectors have a close synergy with IR detectors and are operated in a similar way. This paper presents recent test results for a Rockwell 2K x 2K silicon PIN diode array hybridized to a Hawaii-2RG multiplexer, the Hybrid Visible Silicon Imager (HyViSI). Since the capacitance of the integrating node of Si-PIN diodes is at least a factor of two smaller than the capacitance of the Hawaii-2RG IR detector pixel, lower noise was expected. However, those detectors suffer from interpixel capacitance which introduces an error to the value of the conversion factor measured with the photon transfer method. Therefore QE values have been overestimated by almost a factor of two in the past. Detailed test results on QE, noise, dark current, and other basic performance values as well as a discussion how to interpret the measured values will be presented. Two alternative methods, direct measurement of the nodal capacity and the use of Iron-55 X-rays to determine the actual nodal capacitance and hence the conversion factor will be briefly presented. PSF performance of this detector was analyzed in detail with an optical spot and single pixel reset measurement.

  5. Polarimetric analysis of radar backscatter from ground-based scatterometers and wheat biomass monitoring with advanced synthetic aperture radar images

    NASA Astrophysics Data System (ADS)

    He, Lei; Tong, Ling; Li, Yuxia; Chen, Yan; Tan, Longfei; Guo, Caizheng

    2016-04-01

    This article presents an analysis of the scattering measurements for an entire wheat growth cycle by ground-based scatterometers at a frequency of 5.3 GHz. Since wheat ears are related to wheat growth and yield, the radar backscatter of wheat was analyzed at two different periods, i.e., with and without wheat ears. Simultaneously, parameters such as wheat and soil characteristics as well as volume scattering and soil scattering were analyzed for the two periods during the entire growth cycle. Wheat ears have been demonstrated to have a great influence on radar backscatter; therefore, a modified version of water-cloud model used for retrieving biomass should consider the effect of wheat ears. This work presents two retrieval models based on the water-cloud model and adopts the advanced integral equation model to simulate the soil backscatter before the heading stage and the backscatter from the layer under wheat ears after the heading stage. The research results showed that the biomass retrieved from the advanced synthetic aperture radar (ASAR) images to agree well with the data measured in situ after setting the modified water-cloud model for the growth stages with ears. Furthermore, it was concluded that wheat ears should form an essential component of theoretical modeling as they influence the final yield.

  6. Deep WFPC2 and Ground-Based Imaging of a Complete Sample of 3C Quasars and Galaxies

    NASA Technical Reports Server (NTRS)

    Ridgway, Susan E.; Stockton, Alan

    1997-01-01

    We present the results of an HST and ground-based imaging study of a complete 3C sample of zeta approx. equal to 1 sources, comprising 5 quasars and 5 radio galaxies. We have observed all of the sample in essentially line-free bands at rest-frame 0.33 micrometers with WFPC2 and in rest-frame 1 micrometer images from the ground; we have also observed most of the sample in narrow-band filters centered on [O II]. We resolve continuum structure around all of our quasars in the high-resolution WFPC2 images, and in four of the five ground-based K' images. All of the quasars have some optical continuum structure that is aligned with the radio axis. In at least 3 of these cases, some of this optical structure is directly coincident with a portion of the radio structure, including optical counterparts to radio jets in 3C212 and 3C245 and an optical counterpart to a radio lobe in 3C2. These are most likely due to optical synchrotron radiation, and the radio and optical spectral indices in the northern lobe of 3C2 are consistent with this interpretation. The fact that we see a beamed optical synchotron component in the quasars but not in the radio galaxies complicates both the magnitude and the alignment comparisons. Nonetheless, the total optical and K' flux densities of the quasar hosts are consistent with those of the radio galaxies within the observed dispersion in our sample. The distributions of K' flux densities of both radio galaxies and quasar hosts exhibit similar mean and dispersion to that found for other radio galaxies at this redshift, and the average host galaxy luminosity is equivalent to, or a little fainter than, L*. The formal determination of the alignment in the optical and infrared in the two subsamples yields no significant difference between the radio galaxy and quasar subsamples, and the quasars 3C 196 and 3C 336 have aligned continuum and emission-line structure that is probably not due to beamed optical synchrotron emission. Very blue and/or edge

  7. The fragmentation of dust in the innermost comae of comets: Possible evidence from ground-based images

    NASA Technical Reports Server (NTRS)

    Combi, Michael R.

    1994-01-01

    Dust particles when released from the nucleus of a comet are entrained in the expanding gas flow created by the vaporization of ices (mainly water ice). Traditional approaches to dusty-gas dynamics in the inner comae of comets consider there to be an initial distribution of dust particle sizes which do not fragment or evaporate. The standard Finson-Probstein model (and subsequent variations) yields a one-to-one-to-one correspondence between the size of a dust particle, its terminal velocity owing to gas drag, and its radiation pressure acceleration which creates the notable cometary dust tail. The comparison of a newly developed dust coma model shows that the typical elongated shapes of isophotes in the dust comae of comets on the scale of greater than 10(exp 4) km from the nucleus requires that the one-to-one-to-one relationship between particle size, terminal velocity and radiation pressure acceleration cannot in general be correct. There must be a broad range of particles including those having a small velocity but large radiation pressure acceleration in order to explain the elongated shape. A straightforward way to create such a distribution is if particle fragmentation, or some combination of fragmentation with vaporization, routinely occurs within and/or just outside of the dusty-gas dynamic acceleration region (i.e., up to several hundred km). In this way initially large particles, which are accelerated to fairly slow velocities by gas-drag, fragment to form small particles which still move slowly but are subject to a relatively large radiation pressure acceleration. Fragmentation has already been suggested as one possible interpretation for the flattened gradient in the spatial profiles of dust extracted from Giotto images of Comet Halley. Grain vaporization has been suggested as a possible spatially extended source of coma gases. The general elongated isophote shapes seen in ground-based images for many years represents another possible signature of

  8. The fragmentation of dust in the innermost comae of comets: Possible evidence from ground-based images

    NASA Technical Reports Server (NTRS)

    Combi, Michael R.

    1994-01-01

    Dust particles when released from the nucleus of a comet are entrained in the expanding gas flow created by the vaporization of ices (mainly water ice). Traditional approaches to dusty-gas dynamics in the inner comae of comets consider there to be an initial distribution of dust particle sizes which do not fragment or evaporate. The standard Finson-Probstein model (and subsequent variations) yields a one-to-one-to-one correspondence between the size of a dust particle, its terminal velocity owing to gas drag, and its radiation pressure acceleration which creates the notable cometary dust tail. The comparison of a newly developed dust coma model shows that the typical elongated shapes of isophotes in the dust comae of comets on the scale of greater than 10(exp 4) km from the nucleus requires that the one-to-one-to-one relationship between particle size, terminal velocity and radiation pressure acceleration cannot in general be correct. There must be a broad range of particles including those having a small velocity but large radiation pressure acceleration in order to explain the elongated shape. A straightforward way to create such a distribution is if particle fragmentation, or some combination of fragmentation with vaporization, routinely occurs within and/or just outside of the dusty-gas dynamic acceleration region (i.e., up to several hundred km). In this way initially large particles, which are accelerated to fairly slow velocities by gas-drag, fragment to form small particles which still move slowly but are subject to a relatively large radiation pressure acceleration. Fragmentation has already been suggested as one possible interpretation for the flattened gradient in the spatial profiles of dust extracted from Giotto images of Comet Halley. Grain vaporization has been suggested as a possible spatially extended source of coma gases. The general elongated isophote shapes seen in ground-based images for many years represents another possible signature of

  9. Radiometric Modeling and Calibration of the Geostationary Imaging Fourier Transform Spectrometer (GIFTS)Ground Based Measurement Experiment

    NASA Technical Reports Server (NTRS)

    Tian, Jialin; Smith, William L.; Gazarik, Michael J.

    2008-01-01

    The ultimate remote sensing benefits of the high resolution Infrared radiance spectrometers will be realized with their geostationary satellite implementation in the form of imaging spectrometers. This will enable dynamic features of the atmosphere s thermodynamic fields and pollutant and greenhouse gas constituents to be observed for revolutionary improvements in weather forecasts and more accurate air quality and climate predictions. As an important step toward realizing this application objective, the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) Engineering Demonstration Unit (EDU) was successfully developed under the NASA New Millennium Program, 2000-2006. The GIFTS-EDU instrument employs three focal plane arrays (FPAs), which gather measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The GIFTS calibration is achieved using internal blackbody calibration references at ambient (260 K) and hot (286 K) temperatures. In this paper, we introduce a refined calibration technique that utilizes Principle Component (PC) analysis to compensate for instrument distortions and artifacts, therefore, enhancing the absolute calibration accuracy. This method is applied to data collected during the GIFTS Ground Based Measurement (GBM) experiment, together with simultaneous observations by the accurately calibrated AERI (Atmospheric Emitted Radiance Interferometer), both simultaneously zenith viewing the sky through the same external scene mirror at ten-minute intervals throughout a cloudless day at Logan Utah on September 13, 2006. The accurately calibrated GIFTS radiances are produced using the first four PC scores in the GIFTS-AERI regression model. Temperature and moisture profiles retrieved from the PC-calibrated GIFTS radiances are verified against radiosonde measurements collected throughout the GIFTS sky measurement period. Using the GIFTS GBM calibration model, we compute the calibrated radiances from data

  10. PAMS Photo Image Retrieval Prototype System Design Description

    SciTech Connect

    Conner, M.L., Westinghouse Hanford

    1996-05-02

    This System Design Description (SDD) documents the detail design of the Photo Audio/Visual Management System (PAMS) Photo Image Retrieval Prototype (PPIRP) subsystem. This SDD shows how the software is structured to satisfy the requirements identified in the PAMS Photo Image Prototype Requirements Document. It is a description of the software structure, software components,interfaces, and data that make up the PPIRP subsystem.

  11. Estimates of the Planet Yield from Ground-based High-contrast Imaging Observations as a Function of Stellar Mass

    NASA Astrophysics Data System (ADS)

    Crepp, Justin R.; Johnson, John Asher

    2011-06-01

    We use Monte Carlo simulations to estimate the number of extrasolar planets that are directly detectable in the solar neighborhood using current and forthcoming high-contrast imaging instruments. Our calculations take into consideration the important factors that govern the likelihood for imaging a planet, including the statistical properties of stars in the solar neighborhood, correlations between star and planet properties, observational effects, and selection criteria. We consider several different ground-based surveys, both biased and unbiased, and express the resulting planet yields as a function of stellar mass. Selecting targets based on their youth and visual brightness, we find that strong correlations between star mass and planet properties are required to reproduce high-contrast imaging results to date (i.e., HR 8799, β Pic). Using the most recent empirical findings for the occurrence rate of gas-giant planets from radial velocity (RV) surveys, our simulations indicate that naive extrapolation of the Doppler planet population to semimajor axes accessible to high-contrast instruments provides an excellent agreement between simulations and observations using present-day contrast levels. In addition to being intrinsically young and sufficiently bright to serve as their own beacon for adaptive optics correction, A-stars have a high planet occurrence rate and propensity to form massive planets in wide orbits, making them ideal targets. The same effects responsible for creating a multitude of detectable planets around massive stars conspire to reduce the number orbiting low-mass stars. However, in the case of a young stellar cluster, where targets are approximately the same age and situated at roughly the same distance, MK-stars can easily dominate the number of detections because of an observational bias related to small number statistics. The degree to which low-mass stars produce the most planet detections in this special case depends upon whether multiple

  12. ESTIMATES OF THE PLANET YIELD FROM GROUND-BASED HIGH-CONTRAST IMAGING OBSERVATIONS AS A FUNCTION OF STELLAR MASS

    SciTech Connect

    Crepp, Justin R.; Johnson, John Asher

    2011-06-01

    We use Monte Carlo simulations to estimate the number of extrasolar planets that are directly detectable in the solar neighborhood using current and forthcoming high-contrast imaging instruments. Our calculations take into consideration the important factors that govern the likelihood for imaging a planet, including the statistical properties of stars in the solar neighborhood, correlations between star and planet properties, observational effects, and selection criteria. We consider several different ground-based surveys, both biased and unbiased, and express the resulting planet yields as a function of stellar mass. Selecting targets based on their youth and visual brightness, we find that strong correlations between star mass and planet properties are required to reproduce high-contrast imaging results to date (i.e., HR 8799, {beta} Pic). Using the most recent empirical findings for the occurrence rate of gas-giant planets from radial velocity (RV) surveys, our simulations indicate that naive extrapolation of the Doppler planet population to semimajor axes accessible to high-contrast instruments provides an excellent agreement between simulations and observations using present-day contrast levels. In addition to being intrinsically young and sufficiently bright to serve as their own beacon for adaptive optics correction, A-stars have a high planet occurrence rate and propensity to form massive planets in wide orbits, making them ideal targets. The same effects responsible for creating a multitude of detectable planets around massive stars conspire to reduce the number orbiting low-mass stars. However, in the case of a young stellar cluster, where targets are approximately the same age and situated at roughly the same distance, MK-stars can easily dominate the number of detections because of an observational bias related to small number statistics. The degree to which low-mass stars produce the most planet detections in this special case depends upon whether

  13. Plasmaspheric Shoulders Seen in the Global Euv Images and Its Relation to the Overshielding Electric Field Identified By Ground-Based Magnetometers

    NASA Astrophysics Data System (ADS)

    Yoshikawa, I.; Hamaguchi, T.

    2014-12-01

    We have investigated plasmaspheric EUV images and ground-based magnetic field measurements to understand the formation of the plasmaspheric shoulder. By surveying the all the EUV image of plasmasphere, we have identified the 13 plasmaspheric shoulders. 12 of them were coincident with overshielding identified by magnetic field measurement and emerged in the dawnside. It is most likely that overshielding builds up the plasmaspheric shoulders, as predicted by Goldstein et al. [2002, 2003].

  14. A Ground-Based Mid-Infrared Imaging Survey of Embedded Young Stellar Objects in the Rho Ophiuchi Cloud Core

    NASA Astrophysics Data System (ADS)

    Barsony, M.; Ressler, M. E.; Marsh, K. A.

    2004-12-01

    Results of a comprehensive, new, ground-based mid-infrared imaging survey of the young stellar population of the ρ Ophiuchi cloud are presented. Data were acquired at the Palomar 5-m and at the Keck 10-m telescopes with the MIRLIN and LWS instruments, at 0.5'' and 0.25'' resolutions, respectively. Of 172 survey objects, 85 were detected. A plot of the frequency distribution of the detected objects with SED spectral slope shows that YSOs spend ˜ 3 × 105 yr in the Flat Spectrum phase, clearing out their remnant infall envelopes. Mid-infrared variability is found among a significant fraction of the surveyed objects and is found to occur for all SED classes with optically thick disks. Large amplitude near-infrared variability, also found for all SED classes with optically thick disks, seems to occur with somewhat higher frequency at the earlier evolutionary stages. The highly variable value of K-band veiling that a single source can exhibit in any of the SED classes in which active disk accretion can take place is striking, and is direct observational evidence for highly time-variable accretion activity in disks. Finallly, by comparing mid-infrared vs. near-infrared excesses in a subsample with well-determined effective temperatures and extinction values, disk clearing mechanisms are explored. Financial support for this project through NSF grants AST 00-96087 (CAREER), AST 97-53229 (POWRE), and AST 02-06146 is gratefully acknowledged. MB further thanks the NASA/ASEE Summer Faculty Fellowship program at JPL, that made this work possible.

  15. A Synthesis of Star Calibration Techniques for Ground-Based Narrowband Electron-Multiplying Charge-Coupled Device Imagers Used in Auroral Photometry

    NASA Technical Reports Server (NTRS)

    Grubbs, Guy II; Michell, Robert; Samara, Marilia; Hampton, Don; Jahn, Jorg-Micha

    2016-01-01

    A technique is presented for the periodic and systematic calibration of ground-based optical imagers. It is important to have a common system of units (Rayleighs or photon flux) for cross comparison as well as self-comparison over time. With the advancement in technology, the sensitivity of these imagers has improved so that stars can be used for more precise calibration. Background subtraction, flat fielding, star mapping, and other common techniques are combined in deriving a calibration technique appropriate for a variety of ground-based imager installations. Spectral (4278, 5577, and 8446 A ) ground-based imager data with multiple fields of view (19, 47, and 180 deg) are processed and calibrated using the techniques developed. The calibration techniques applied result in intensity measurements in agreement between different imagers using identical spectral filtering, and the intensity at each wavelength observed is within the expected range of auroral measurements. The application of these star calibration techniques, which convert raw imager counts into units of photon flux, makes it possible to do quantitative photometry. The computed photon fluxes, in units of Rayleighs, can be used for the absolute photometry between instruments or as input parameters for auroral electron transport models.

  16. A Synthesis of Star Calibration Techniques for Ground-Based Narrowband Electron-Multiplying Charge-Coupled Device Imagers Used in Auroral Photometry

    NASA Technical Reports Server (NTRS)

    Grubbs, Guy II; Michell, Robert; Samara, Marilia; Hampton, Don; Jahn, Jorg-Micha

    2016-01-01

    A technique is presented for the periodic and systematic calibration of ground-based optical imagers. It is important to have a common system of units (Rayleighs or photon flux) for cross comparison as well as self-comparison over time. With the advancement in technology, the sensitivity of these imagers has improved so that stars can be used for more precise calibration. Background subtraction, flat fielding, star mapping, and other common techniques are combined in deriving a calibration technique appropriate for a variety of ground-based imager installations. Spectral (4278, 5577, and 8446 A ) ground-based imager data with multiple fields of view (19, 47, and 180 deg) are processed and calibrated using the techniques developed. The calibration techniques applied result in intensity measurements in agreement between different imagers using identical spectral filtering, and the intensity at each wavelength observed is within the expected range of auroral measurements. The application of these star calibration techniques, which convert raw imager counts into units of photon flux, makes it possible to do quantitative photometry. The computed photon fluxes, in units of Rayleighs, can be used for the absolute photometry between instruments or as input parameters for auroral electron transport models.

  17. The First Light for a New Ground-based Imaging Capability of JHU/APL in Support of Auroral Science Campaigns and Missions

    NASA Astrophysics Data System (ADS)

    Hsieh, S. Y. W.; Sibeck, D. G.; Hampton, D. L.

    2016-12-01

    A new ground-based imaging capability, GoIono, has been developed at JHU/APL. The deployable system includes an all-sky imager with multiple filters to address both auroral science and space weather applications. This presentation introduces this new capability to the science community. We will present and discuss initial Golono observations at the Poker Flat Research Range for a successful auroral substorm campaign conducted during early April 2016. The APL GoIono all-sky imagers are ready for deployment at sub-auroral latitudes to support the Van Allen Probes (and other) missions. They will form a cornerstone of the ground-based measurements needed in support of the forthcoming SMILE mission.

  18. Subspace-based prototyping and classification of chromosome images.

    PubMed

    Wu, Qiang; Liu, Zhongmin; Chen, Tiehan; Xiong, Zixiang; Castleman, Kenneth R

    2005-09-01

    Chromosomes are essential genomic information carriers. Chromosome classification constitutes an important part of routine clinical and cancer cytogenetics analysis. Cytogeneticists perform visual interpretation of banded chromosome images according to the diagrammatic models of various chromosome types known as the ideograms, which mimic artists' depiction of the chromosomes. In this paper, we present a subspace-based approach for automated prototyping and classification of chromosome images. We show that 1) prototype chromosome images can be quantitatively synthesized from a subspace to objectively represent the chromosome images of a given type or population, and 2) the transformation coefficients (or projected coordinate values of sample chromosomes) in the subspace can be utilized as the extracted feature measurements for classification purposes. We examine in particular the formation of three well-known subspaces, namely the ones derived from principal component analysis (PCA), Fisher's linear discriminant analysis, and the discrete cosine transform (DCT). These subspaces are implemented and evaluated for prototyping two-dimensional (2-D) images and for classification of both 2-D images and one-dimensional profiles of chromosomes. Experimental results show that previously unseen prototype chromosome images of high visual quality can be synthesized using the proposed subspace-based method, and that PCA and the DCT significantly outperform the well-known benchmark technique of weighted density distribution functions in classifying 2-D chromosome images.

  19. Large scale rock slope release planes imaged by differential ground based InSAR at Randa, Switzerland

    NASA Astrophysics Data System (ADS)

    Gischig, V.; Loew, S.; Kos, A.; Raetzo, H.

    2009-04-01

    In April and May of 1991 a steep rock slope above the village of Randa (Valais, Switzerland) failed in two events, releasing a total rock volume of 30 million m3. The rock mass behind the back scarp contains several million cubic meters of unstable gneisses and schists which are moving with a maximum rate of about 2 cm/yr. Different geodetic, geotechnical and geophysical techniques were applied to monitor this new instability and to determine its spatial extent. However, the boundaries of the instability could only be roughly estimated so far. For this reason five ground based differential InSAR surveys (GB-DInSAR) were carried out between 2005 and 2007 from the opposite valley flank at a distance to target of 1.3 to 1.9 km. These surveys provide displacements maps of four different time intervals with a spatial resolution of 2 to 6 m and an accuracy of less than 1 mm. These datasets reveal interesting new insights into the spatial distribution of displacements and significantly contribute to the kinematic interpretation of the ongoing movements. We found that the lower boundary of the instability is a narrow rupture plane which coincides with a primary lithological boundary on the slope. The intersection line between this basal rupture plane and the steep rock cliff extents over at least 200 m meters. It is possible to identify this structure on helicopter-based high resolution images and a LiDAR DTM of the failure surface. The eastern boundary of the instability also presents itself as a sharp line separating stable bedrock from a strongly fractured rock mass moving about 1 cm/yr along the line of sight. This lateral release plane is formed by a steeply east dipping tectonic fault plane, with subhorizontal striations and an exposed surface area of about 10'000 square meters. In the north-east of the instability the lateral boundaries crop out on surfaces that have an acute angle to the line of sight or lie in the shadow of the radar. Here the boundaries of the

  20. Prototype Videodisk-Based Part-Task Thermal Imaging Trainer

    NASA Technical Reports Server (NTRS)

    Brickner, Michael S.; Foyle, David C.; Sridhar, Banavar (Technical Monitor)

    1995-01-01

    Thermal images, or infrared images, are representations of the world based on heat, instead of visible light. Research has shown that the resulting thermal image results in perceptual differences leading to difficulties in interpretation (e.g., the determination of slope angle, concavity/convexity), or increased identification latencies. A joint research project between the United States (NASA and U.S. Army) and Israel (Ministry of Defense and Israel Air Force) has resulted in the development of a prototype part-task trainer for the acquisition of perceptual skills associated with thermal imaging usage. This prototype system is videodisk-based under computer control, using recordings of thermal images. A lesson section introduces declarative knowledge, in which the basic physics and heuristics of thermal imagery are taught. An exercise section teaches procedural knowledge, with the user viewing dynamic, actual imagery, with an interactive detection/location determination task. The general philosophy and design of the trainer will be demonstrated.

  1. PAMS photo image retrieval prototype alternatives analysis

    SciTech Connect

    Conner, M.L.

    1996-04-30

    Photography and Audiovisual Services uses a system called the Photography and Audiovisual Management System (PAMS) to perform order entry and billing services. The PAMS system utilizes Revelation Technologies database management software, AREV. Work is currently in progress to link the PAMS AREV system to a Microsoft SQL Server database engine to provide photograph indexing and query capabilities. The link between AREV and SQLServer will use a technique called ``bonding.`` This photograph imaging subsystem will interface to the PAMS system and handle the image capture and retrieval portions of the project. The intent of this alternatives analysis is to examine the software and hardware alternatives available to meet the requirements for this project, and identify a cost-effective solution.

  2. Image Understanding Architecture Prototype Evaluation and Development

    DTIC Science & Technology

    1993-06-01

    database at the intermediate level is a more fundamental requirement than supporting particular algorithms. -i.. vii I TABLE OF CONTENTS I...57 I 3.3 Intermediate-level Symbolic Representation (ISR) Database ............ 64 3.3.1 Intermediate Symbolic Representation (ISR...ICAP, because the ICAP representation is in approximate registration with the original image events in the CAAPP. The ICAP serves as a database for the

  3. Application of Technical Measures and Software in Constructing Photorealistic 3D Models of Historical Building Using Ground-Based and Aerial (UAV) Digital Images

    NASA Astrophysics Data System (ADS)

    Zarnowski, Aleksander; Banaszek, Anna; Banaszek, Sebastian

    2015-12-01

    Preparing digital documentation of historical buildings is a form of protecting cultural heritage. Recently there have been several intensive studies using non-metric digital images to construct realistic 3D models of historical buildings. Increasingly often, non-metric digital images are obtained with unmanned aerial vehicles (UAV). Technologies and methods of UAV flights are quite different from traditional photogrammetric approaches. The lack of technical guidelines for using drones inhibits the process of implementing new methods of data acquisition. This paper presents the results of experiments in the use of digital images in the construction of photo-realistic 3D model of a historical building (Raphaelsohns' Sawmill in Olsztyn). The aim of the study at the first stage was to determine the meteorological and technical conditions for the acquisition of aerial and ground-based photographs. At the next stage, the technology of 3D modelling was developed using only ground-based or only aerial non-metric digital images. At the last stage of the study, an experiment was conducted to assess the possibility of 3D modelling with the comprehensive use of aerial (UAV) and ground-based digital photographs in terms of their labour intensity and precision of development. Data integration and automatic photo-realistic 3D construction of the models was done with Pix4Dmapper and Agisoft PhotoScan software Analyses have shown that when certain parameters established in an experiment are kept, the process of developing the stock-taking documentation for a historical building moves from the standards of analogue to digital technology with considerably reduced cost.

  4. Prototype System For Digital Image Management In Combat Casualty Care

    NASA Astrophysics Data System (ADS)

    Nadel, Lawrence D.; Forrester, Mark A.; Glenn, Marcus E.; Johnson, William P.; Lafko, David A.; Goeringer, Fred

    1989-05-01

    By the early 1990s, the U.S. Army intends to implement all-digital, filmless medical imaging throughout its deployable combat health care facilities. In addition to employing imaging devices whose outputs are comprised of digital, electronic images rather than film-based images, such a system must, at a minimum, include means for storing, displaying, and transporting the resultant images in accordance with existing military doctrine. Furthermore, compatibility with fixed medical facilities, both in the continental United States (CONUS) and elsewhere, and between military services must be assured to promote continuity of care. The aim of this undertaking is to develop an understanding of the imaging needs of the U.S. Army's deployable/combat Health Services Support (HSS) system, and address these needs in a prototype Digital Imaging Network System (DINS) (also known as Picture Archiving and Communication System (PACS) or an Image Management and Communication (IMAC) System), to be integrated and evaluated by The MITRE Corporation. The prototype will undergo iterative development by subjecting it to multiple evaluations in both the laboratory and Echelon 3 environments, by military and civilian medical, scientific, and engineering personnel. This project is part of a U.S. Army Medical Research and Development Command contract to The MITRE Corporation to assess the feasibility of filmless imaging in military health care.

  5. Spectral characterization of forest damage occurring on Whiteface Mountain, NY - Studies with the Fluorescence Line Imager (FLI) and ground-based spectrometers

    NASA Technical Reports Server (NTRS)

    Rock, B. N.; Moss, D. M.; Miller, J. R.; Freemantle, J. R.; Boyer, M. G.

    1990-01-01

    Ground-based spectral characteristics of fir wave damage and an analysis of calibrated FLI data acquired along the same fir wave utilized for the in situ measurements are presented. Derivative curve data were produced from both in situ and FLI reflectance measurements for the red edge spectral region for birch and for various portions of a fir wave. The results suggested that with proper atmospheric correction of airborne imaging spectrometer data sets, the derivative curve approach will provide an accurate means of assessing red edge parameters, and that such data will permit identification of specific types of forest damage on the basis of spectral fine features.

  6. Prototype of a rectal wall ultrasound image analysis system

    NASA Astrophysics Data System (ADS)

    Xiao, Di; Ng, Wan S.; Abeyratne, Udantha R.; Tsang, Charles B.

    2002-05-01

    This paper presents a software system prototype for rectal wall ultrasound image processing, image display and 3D reconstruction and visualization of the rectal wall structure, which is aimed to help surgeons cope with large quantities of rectal wall ultrasound images. On the core image processing algorithm part, a novel multigradient field active contour model proposed by authors is used to complete the multi-layer boundary detection of the rectal wall. A novel unifying active contour model, which combines region information, gradient information and contour's internal constraint, is developed for tumor boundary detection. The region statistical information is described accurately by Gaussian Mixture Model, whose parameter solution is computed by Expectation-Maximization algorithm. The whole system is set up on Java platform. Java JAI technology is used for 2D image display, Java3D technology is employed for 3D reconstruction and visualization. The system prototype is currently composed of three main modules: image processing, image display and 3D visualization.

  7. Multipurpose underwater imaging and ranging camera: prototype system performance

    NASA Astrophysics Data System (ADS)

    Gleckler, Anthony D.; Pittner, Anthony

    2000-07-01

    SEACAM is a combination of a digital camera and an underwater sonar range finder that allows the precise range to the target to be measured simultaneously with the image. Given this measured range and the known field of view of the camera, the `plate scale' of the image (i.e., the number of millimeters/pixel) can be precisely determined, allowing for accurate estimates of the target dimensions. Two prototype systems have been developed: a `functional' camera that has all the functional capability of the final camera, but which is not packaged in the final form; and an `ergonomic' prototype that represents the first attempt at the final package design, but which is non-functional.

  8. In-operation field-of-view retrieval (IFR) for satellite and ground-based DOAS-type instruments applying coincident high-resolution imager data

    NASA Astrophysics Data System (ADS)

    Sihler, Holger; Lübcke, Peter; Lang, Rüdiger; Beirle, Steffen; de Graaf, Martin; Hörmann, Christoph; Lampel, Johannes; Penning de Vries, Marloes; Remmers, Julia; Trollope, Ed; Wang, Yang; Wagner, Thomas

    2017-03-01

    Knowledge of the field of view (FOV) of a remote sensing instrument is particularly important when interpreting their data and merging them with other spatially referenced data. Especially for instruments in space, information on the actual FOV, which may change during operation, may be difficult to obtain. Also, the FOV of ground-based devices may change during transportation to the field site, where appropriate equipment for the FOV determination may be unavailable. This paper presents an independent, simple and robust method to retrieve the FOV of an instrument during operation, i.e. the two-dimensional sensitivity distribution, sampled on a discrete grid. The method relies on correlated measurements featuring a significantly higher spatial resolution, e.g. by an imaging instrument accompanying a spectrometer. The method was applied to two satellite instruments, GOME-2 and OMI, and a ground-based differential optical absorption spectroscopy (DOAS) instrument integrated in an SO2 camera. For GOME-2, quadrangular FOVs could be retrieved, which almost perfectly match the provided FOV edges after applying a correction for spatial aliasing inherent to GOME-type instruments. More complex sensitivity distributions were found at certain scanner angles, which are probably caused by degradation of the moving parts within the instrument. For OMI, which does not feature any moving parts, retrieved sensitivity distributions were much smoother compared to GOME-2. A 2-D super-Gaussian with six parameters was found to be an appropriate model to describe the retrieved OMI FOV. The comparison with operationally provided FOV dimensions revealed small differences, which could be mostly explained by the limitations of our IFR implementation. For the ground-based DOAS instrument, the FOV retrieved using SO2-camera data was slightly smaller than the flat-disc distribution, which is assumed by the state-of-the-art correlation technique. Differences between both methods may be

  9. Comparison of DSMs acquired by terrestrial laser scanning, UAV-based aerial images and ground-based optical images at the Super-Sauze landslide

    NASA Astrophysics Data System (ADS)

    Rothmund, Sabrina; Niethammer, Uwe; Walter, Marco; Joswig, Manfred

    2013-04-01

    In recent years, the high-resolution and multi-temporal 3D mapping of the Earth's surface using terrestrial laser scanning (TLS), ground-based optical images and especially low-cost UAV-based aerial images (Unmanned Aerial Vehicle) has grown in importance. This development resulted from the progressive technical improvement of the imaging systems and the freely available multi-view stereo (MVS) software packages. These different methods of data acquisition for the generation of accurate, high-resolution digital surface models (DSMs) were applied as part of an eight-week field campaign at the Super-Sauze landslide (South French Alps). An area of approximately 10,000 m² with long-term average displacement rates greater than 0.01 m/day has been investigated. The TLS-based point clouds were acquired at different viewpoints with an average point spacing between 10 to 40 mm and at different dates. On these days, more than 50 optical images were taken on points along a predefined line on the side part of the landslide by a low-cost digital compact camera. Additionally, aerial images were taken by a radio-controlled mini quad-rotor UAV equipped with another low-cost digital compact camera. The flight altitude ranged between 20 m and 250 m and produced a corresponding ground resolution between 0.6 cm and 7 cm. DGPS measurements were carried out as well in order to geo-reference and validate the point cloud data. To generate unscaled photogrammetric 3D point clouds from a disordered and tilted image set, we use the widespread open-source software package Bundler and PMVS2 (University of Washington). These multi-temporal DSMs are required on the one hand to determine the three-dimensional surface deformations and on the other hand it will be required for differential correction for orthophoto production. Drawing on the example of the acquired data at the Super-Sauze landslide, we demonstrate the potential but also the limitations of the photogrammetric point clouds. To

  10. Prototype Focal-Plane-Array Optoelectronic Image Processor

    NASA Technical Reports Server (NTRS)

    Fang, Wai-Chi; Shaw, Timothy; Yu, Jeffrey

    1995-01-01

    Prototype very-large-scale integrated (VLSI) planar array of optoelectronic processing elements combines speed of optical input and output with flexibility of reconfiguration (programmability) of electronic processing medium. Basic concept of processor described in "Optical-Input, Optical-Output Morphological Processor" (NPO-18174). Performs binary operations on binary (black and white) images. Each processing element corresponds to one picture element of image and located at that picture element. Includes input-plane photodetector in form of parasitic phototransistor part of processing circuit. Output of each processing circuit used to modulate one picture element in output-plane liquid-crystal display device. Intended to implement morphological processing algorithms that transform image into set of features suitable for high-level processing; e.g., recognition.

  11. On the Potential Implementation of Ground-based Scanning & Imaging LIDARs on Future Surface Planetary Exploration Missions

    NASA Astrophysics Data System (ADS)

    Singhania, A.; Fernandez, J. C.

    2006-12-01

    To this date Landers and Rovers used in planetary exploration have relied on stereoscopic camera systems to provide 3D information used to perform both scientific imaging and navigation tasks. Despite being highly reliable, stereoscopic systems have several limitations in the creation of accurate 3D models. Light Detection and Ranging (LIDAR) systems have evolved from simple ranging devices used as altimeters to complex mapping systems capable of developing highly accurate 3D models. Data collected using a COTS Scanning and Imaging LIDAR (SIL) under simulated planetary surface conditions is presented and evaluated as an alternative to the traditional stereoscopic imaging systems, to provide navigation and scientific data for future planetary surface missions. SIL data set includes 3D spatial information (XYZ coordinates), laser return intensity and mapped to each laser point, the RGB pixel value obtained from the imaging sensor. The main advantage of SIL over stereo cameras is that it establishes a precise Cartesian coordinate system which enables the scientific and imaging data to be integrated into a single spatially coherent data set. A complete description of the pros and cons between stereo imagers and SIL is given.

  12. Rapid prototyping in the development of image processing systems

    NASA Astrophysics Data System (ADS)

    von der Fecht, Arno; Kelm, Claus Thomas

    2004-08-01

    This contribution presents a rapid prototyping approach for the real-time demonstration of image processing algorithms. As an example EADS/LFK has developed a basic IR target tracking system implementing this approach. Traditionally in research and industry time-independent simulation of image processing algorithms on a host computer is processed. This method is good for demonstrating the algorithms' capabilities. Rarely done is a time-dependent simulation or even a real-time demonstration on a target platform to prove the real-time capabilities. In 1D signal processing applications time-dependent simulation and real-time demonstration has already been used for quite a while. For time-dependent simulation Simulink from The MathWorks has established as an industry standard. Combined with The MathWorks' Real-Time Workshop the simulation model can be transferred to a real-time target processor. The executable is generated automatically by the Real-Time Workshop directly out of the simulation model. In 2D signal processing applications like image processing The Mathworks' Matlab is commonly used for time-independent simulation. To achieve time-dependent simulation and real-time demonstration capabilities the algorithms can be transferred to Simulink, which in fact runs on top of Matlab. Additionally to increase the performance Simulink models or parts of them can be transferred to Xilinx FPGAs using Xilinx' System Generator. With a single model and the automatic workflow both, a time-dependant simulation and the real-time demonstration, are covered leading to an easy and flexible rapid prototyping approach. EADS/LFK is going to use this approach for a wider spectrum of IR image processing applications like automatic target recognition or image based navigation or imaging laser radar target recognition.

  13. Venus Cloud Morphology and Motions from Ground-based Images at the Time of the Akatsuki Orbit Insertion

    NASA Astrophysics Data System (ADS)

    Sánchez-Lavega, A.; Peralta, J.; Gomez-Forrellad, J. M.; Hueso, R.; Pérez-Hoyos, S.; Mendikoa, I.; Rojas, J. F.; Horinouchi, T.; Lee, Y. J.; Watanabe, S.

    2016-12-01

    We report Venus image observations around the two maximum elongations of the planet at 2015 June and October. From these images we describe the global atmospheric dynamics and cloud morphology in the planet before the arrival of JAXA’s Akatsuki mission on 2015 December 7. The majority of the images were acquired at ultraviolet wavelengths (380-410 nm) using small telescopes. The Venus dayside was also observed with narrowband filters at other wavelengths (890 nm, 725-950 nm, 1.435 μm CO2 band) using the instrument PlanetCam-UPV/EHU at the 2.2 m telescope in Calar Alto Observatory. In all cases, the lucky imaging methodology was used to improve the spatial resolution of the images over the atmospheric seeing. During the April-June period, the morphology of the upper cloud showed an irregular and chaotic texture with a well-developed equatorial dark belt (afternoon hemisphere), whereas during October-December the dynamical regime was dominated by planetary-scale waves (Y-horizontal, C-reversed, and ψ-horizontal features) formed by long streaks, and banding suggesting more stable conditions. Measurements of the zonal wind velocity with cloud tracking in the latitude range from 50°N to 50°S shows agreement with retrievals from previous works. Partially based on observations obtained at Centro Astronómico Hispano Alemán, Observatorio de Calar Alto MPIA-CSIC, Almería, Spain.

  14. Development of mid-infrared spectrometer with an image slicer (MIRSIS) for ground-based astronomy: developing optical and mechanical mounts

    NASA Astrophysics Data System (ADS)

    Okamoto, Yoshiko Kataza; Kataza, Hirokazu; Sato, Keigo; Manabe, Kei; Mitsui, Kenji; Okada, Norio; Fukushima, Mitsuhiro; Nishino, Tetsuo; Tomita, Koji; Tosa, Masamune; Onaka, Takashi

    2008-07-01

    Mid-Infrared Spectrometer with an Image Slicer (MIRSIS) is a 10micron band spectrometer for ground-based observations. Based on the optical design reported in Okamoto et al. (2006), we recently developed most of optical elements and their mounts. There, we adopted designs based on an ultra-precision cut for the slice mirrors and the pupil mirrors. We also designed and partly manufactured the optical parts with switching/adjusting mechanism with cryogenic step motors. Since MIRSIS has a very complicated stereoscopic configuration of optical elements, we developed a method to adjust the optical alignment where relative positional markers and a three-dimensional measuring system are combined. We confirmed that we can achieve position and angular adjustment with error down to 0.1mm and 0.05degree through alignment test with a pair of mirrors.

  15. Ground-based astrometry with wide field imagers. V. Application to near-infrared detectors: HAWK-I@VLT/ESO

    NASA Astrophysics Data System (ADS)

    Libralato, M.; Bellini, A.; Bedin, L. R.; Piotto, G.; Platais, I.; Kissler-Patig, M.; Milone, A. P.

    2014-03-01

    High-precision astrometry requires accurate point-spread function modeling and accurate geometric-distortion corrections. This paper demonstrates that it is possible to achieve both requirements with data collected at the high acuity wide-field K-band imager (HAWK-I), a wide-field imager installed at the Nasmyth focus of UT4/VLT ESO 8 m telescope. Our final astrometric precision reaches ~3 mas per coordinate for a well-exposed star in a single image with a systematic error less than 0.1 mas. We constructed calibrated astro-photometric catalogs and atlases of seven fields: the Baade's window, NGC 6656, NGC 6121, NGC 6822, NGC 6388, NGC 104, and the James Webb Space Telescope calibration field (in the Large Magellanic Cloud). We make these catalogs and images electronically available to the community. Furthermore, as a demonstration of the efficacy of our approach, we combined archival material taken with the optical wide-field imager at the MPI/ESO 2.2 m with HAWK-I observations. We showed that we are able to achieve an excellent separation between cluster members and field objects for NGC 6656 and NGC 6121 with a time base-line of about 8 years. Using both HST and HAWK-I data, we also study the radial distribution of the SGB populations in NGC 6656 and conclude that the radial trend is flat within our uncertainty. We also provide membership probabilities for most of the stars in NGC 6656 and NGC 6121 catalogs and estimate membership for the published variable stars in these two fields. Catalogs, fortran code, and distortion maps are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A80Based on observations with the 8 m VLT ESO telescope.

  16. Development of a compressive sampling hyperspectral imager prototype

    NASA Astrophysics Data System (ADS)

    Barducci, Alessandro; Guzzi, Donatella; Lastri, Cinzia; Nardino, Vanni; Marcoionni, Paolo; Pippi, Ivan

    2013-10-01

    Compressive sensing (CS) is a new technology that investigates the chance to sample signals at a lower rate than the traditional sampling theory. The main advantage of CS is that compression takes place during the sampling phase, making possible significant savings in terms of the ADC, data storage memory, down-link bandwidth, and electrical power absorption. The CS technology could have primary importance for spaceborne missions and technology, paving the way to noteworthy reductions of payload mass, volume, and cost. On the contrary, the main CS disadvantage is made by the intensive off-line data processing necessary to obtain the desired source estimation. In this paper we summarize the CS architecture and its possible implementations for Earth observation, giving evidence of possible bottlenecks hindering this technology. CS necessarily employs a multiplexing scheme, which should produce some SNR disadvantage. Moreover, this approach would necessitate optical light modulators and 2-dim detector arrays of high frame rate. This paper describes the development of a sensor prototype at laboratory level that will be utilized for the experimental assessment of CS performance and the related reconstruction errors. The experimental test-bed adopts a push-broom imaging spectrometer, a liquid crystal plate, a standard CCD camera and a Silicon PhotoMultiplier (SiPM) matrix. The prototype is being developed within the framework of the ESA ITI-B Project titled "Hyperspectral Passive Satellite Imaging via Compressive Sensing".

  17. Ground-based portable radar interferometer for imaging glacier flow, ocean-glacier ice interactions, and river ice breakup

    NASA Astrophysics Data System (ADS)

    Fahnestock, M. A.; Cassotto, R.; Truffer, M.

    2013-12-01

    Over the last 18 months we have deployed new 17 GHz imaging radars from Gamma Remote Sensing to document flow on land terminating and tidewater glaciers in Greenland and Alaska; to image glacier response to tides and calving; to track floating ice in fjords; and to document river ice movement, ice jams, and associated flooding during breakup on the Tanana River in Alaska. During these deployments we have learned much about atmospheric influences on interferometric measurements; combination of flow direction determinations from feature tracking in amplitude imagery with short-term flow variability from interferometry. We show examples documenting measurement capabilities and limitations from each of these deployments. These radars represent unique tools for study of rapid changes in dynamic parts of the cryosphere.

  18. RINGFINDER: Automated detection of galaxy-scale gravitational lenses in ground-based multi-filter imaging data

    SciTech Connect

    Gavazzi, Raphaël; Marshall, Philip J.; Treu, Tommaso; Sonnenfeld, Alessandro

    2014-04-20

    We present RINGFINDER, a tool for finding galaxy-scale strong gravitational lenses in multi-band imaging data. By construction, the method is sensitive to configurations involving a massive foreground ETG and a faint, background, blue source. RINGFINDER detects the presence of blue residuals embedded in an otherwise smooth red light distribution by difference imaging in two bands. The method is automated for efficient application to current and future surveys, having originally been designed for the 150 deg{sup 2} Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). We describe each of the steps of RINGFINDER. We then carry out extensive simulations to assess completeness and purity. For sources with magnification μ > 4, RINGFINDER reaches 42% (25%) completeness and 29% (86%) purity before (after) visual inspection. The completeness of RINGFINDER is substantially improved in the particular range of Einstein radii 0.''8 ≤ R {sub Ein} ≤ 2.''0 and lensed images brighter than g = 22.5, where it can be as high as ∼70%. RINGFINDER does not introduce any significant bias in the source or deflector population. We conclude by presenting the final catalog of RINGFINDER CFHTLS galaxy-scale strong lens candidates. Additional information obtained with Hubble Space Telescope and Keck adaptive optics high-resolution imaging, and with Keck and Very Large Telescope spectroscopy, is used to assess the validity of our classification and measure the redshift of the foreground and the background objects. From an initial sample of 640,000 ETGs, RINGFINDER returns 2500 candidates, which we further reduce by visual inspection to 330 candidates. We confirm 33 new gravitational lenses from the main sample of candidates, plus an additional 16 systems taken from earlier versions of RINGFINDER. First applications are presented in the Strong Lensing Legacy Survey galaxy-scale lens sample paper series.

  19. Ground-based demonstration of imaging SWIR-FTS for space-based detection of air pollution and greenhouse gases

    NASA Astrophysics Data System (ADS)

    Imai, Tadashi; Murooka, Jumpei; Kuze, Akihiko; Suto, Hiroshi; Sato, Ryota

    2013-10-01

    Fourier transform spectrometer (FTS) has many advantages, especially for greenhouse gases and air pollution detection in the atmosphere, because a single instrument can provide wide spectral coverage and high spectral resolution with highly stabilized instrumental line function for all wavenumbers. Several channels are usually required to derive the column amount or vertical profile of a target species. Near infrared (NIR) and shortwave infrared (SWIR) spectral regions are very attractive for remote sensing applications. The GHG and CO of precursors of air pollution have absorption lines in the SWIR region, and the sensitivity against change in the amounts in the boundary layer is high enough to measure mole fractions near the Earth surface. One disadvantage of conventional space-based FTS is the spatial density of effective observation. To improve the effective numbers of observations, an imaging FTS coupled with a two-dimensional (2D)-camera was considered. At first, a mercury cadmium telluride (MCT)-based imaging FTS was considered. However, an MCT-based system requires a calibration source (black body and deep-space view) and a highly accurate and super-low temperature control system for the MCT detector. As a result, size, weight, and power consumption are increased and the cost of the instrument becomes too high. To reduce the size, weight, power consumption, and cost, a commercial 2D indium gallium arsenide (InGaAs) camera can be used to detect SWIR light. To demonstrate a small imaging SWIR-FTS (IS-FTS), an imaging FTS coupled with a commercial 2D InGaAs camera was developed. In the demonstration, the CH4 gas cell was equipped with an IS-FTS for the absorber to make the spectra in the SWIR region. The spectra of CH4 of the IS-FTS demonstration model were then compared with those of traditional FTS. The spectral agreement between the traditional and IS-FTS instruments was very good.

  20. RINGFINDER: Automated Detection of Galaxy-scale Gravitational Lenses in Ground-based Multi-filter Imaging Data

    NASA Astrophysics Data System (ADS)

    Gavazzi, Raphaël; Marshall, Philip J.; Treu, Tommaso; Sonnenfeld, Alessandro

    2014-04-01

    We present RINGFINDER, a tool for finding galaxy-scale strong gravitational lenses in multi-band imaging data. By construction, the method is sensitive to configurations involving a massive foreground ETG and a faint, background, blue source. RINGFINDER detects the presence of blue residuals embedded in an otherwise smooth red light distribution by difference imaging in two bands. The method is automated for efficient application to current and future surveys, having originally been designed for the 150 deg2 Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). We describe each of the steps of RINGFINDER. We then carry out extensive simulations to assess completeness and purity. For sources with magnification μ > 4, RINGFINDER reaches 42% (25%) completeness and 29% (86%) purity before (after) visual inspection. The completeness of RINGFINDER is substantially improved in the particular range of Einstein radii 0.''8 <= R Ein <= 2.''0 and lensed images brighter than g = 22.5, where it can be as high as ~70%. RINGFINDER does not introduce any significant bias in the source or deflector population. We conclude by presenting the final catalog of RINGFINDER CFHTLS galaxy-scale strong lens candidates. Additional information obtained with Hubble Space Telescope and Keck adaptive optics high-resolution imaging, and with Keck and Very Large Telescope spectroscopy, is used to assess the validity of our classification and measure the redshift of the foreground and the background objects. From an initial sample of 640,000 ETGs, RINGFINDER returns 2500 candidates, which we further reduce by visual inspection to 330 candidates. We confirm 33 new gravitational lenses from the main sample of candidates, plus an additional 16 systems taken from earlier versions of RINGFINDER. First applications are presented in the Strong Lensing Legacy Survey galaxy-scale lens sample paper series.

  1. JWST tunable filter imager: etalon prototype test results

    NASA Astrophysics Data System (ADS)

    Touahri, D.; Cameron, P.; Evans, C.; Greenberg, E.; Rowlands, N.; Scott, A.; Doyon, R.; Beaulieu, M.; Djazovski, O.

    2008-07-01

    We present the prototyping results and laboratory characterization of a narrow band Fabry-Perot etalon flight model which is one of the wavelength selecting elements of the Tunable Filter Imager. The latter is a part of the Fine Guidance Sensor which represents the Canadian contribution to NASA's James Webb Space Telescope. The unique design of this etalon provides the JWST observatory with the ability to image at 30 Kelvin, a 2.2'x2.2' portion of its field of view in a narrow spectral bandwidth of R~100 at any wavelength ranging between 1.6 and 4.9 μm (with a gap in coverage between 2.5 and 3.2 μm). Extensive testing has resulted in better understanding of the thermal properties of the piezoelectric transducers used as an actuation system for the etalon gap tuning. Good throughput, spectral resolution and contrast have been demonstrated for the full wavelength range.

  2. Rapid prototyping of biomimetic vascular phantoms for hyperspectral reflectance imaging

    PubMed Central

    Ghassemi, Pejhman; Wang, Jianting; Melchiorri, Anthony J.; Ramella-Roman, Jessica C.; Mathews, Scott A.; Coburn, James C.; Sorg, Brian S.; Chen, Yu; Joshua Pfefer, T.

    2015-01-01

    Abstract. The emerging technique of rapid prototyping with three-dimensional (3-D) printers provides a simple yet revolutionary method for fabricating objects with arbitrary geometry. The use of 3-D printing for generating morphologically biomimetic tissue phantoms based on medical images represents a potentially major advance over existing phantom approaches. Toward the goal of image-defined phantoms, we converted a segmented fundus image of the human retina into a matrix format and edited it to achieve a geometry suitable for printing. Phantoms with vessel-simulating channels were then printed using a photoreactive resin providing biologically relevant turbidity, as determined by spectrophotometry. The morphology of printed vessels was validated by x-ray microcomputed tomography. Channels were filled with hemoglobin (Hb) solutions undergoing desaturation, and phantoms were imaged with a near-infrared hyperspectral reflectance imaging system. Additionally, a phantom was printed incorporating two disjoint vascular networks at different depths, each filled with Hb solutions at different saturation levels. Light propagation effects noted during these measurements—including the influence of vessel density and depth on Hb concentration and saturation estimates, and the effect of wavelength on vessel visualization depth—were evaluated. Overall, our findings indicated that 3-D-printed biomimetic phantoms hold significant potential as realistic and practical tools for elucidating light–tissue interactions and characterizing biophotonic system performance. PMID:26662064

  3. Rapid prototyping of biomimetic vascular phantoms for hyperspectral reflectance imaging

    NASA Astrophysics Data System (ADS)

    Ghassemi, Pejhman; Wang, Jianting; Melchiorri, Anthony J.; Ramella-Roman, Jessica C.; Mathews, Scott A.; Coburn, James C.; Sorg, Brian S.; Chen, Yu; Joshua Pfefer, T.

    2015-12-01

    The emerging technique of rapid prototyping with three-dimensional (3-D) printers provides a simple yet revolutionary method for fabricating objects with arbitrary geometry. The use of 3-D printing for generating morphologically biomimetic tissue phantoms based on medical images represents a potentially major advance over existing phantom approaches. Toward the goal of image-defined phantoms, we converted a segmented fundus image of the human retina into a matrix format and edited it to achieve a geometry suitable for printing. Phantoms with vessel-simulating channels were then printed using a photoreactive resin providing biologically relevant turbidity, as determined by spectrophotometry. The morphology of printed vessels was validated by x-ray microcomputed tomography. Channels were filled with hemoglobin (Hb) solutions undergoing desaturation, and phantoms were imaged with a near-infrared hyperspectral reflectance imaging system. Additionally, a phantom was printed incorporating two disjoint vascular networks at different depths, each filled with Hb solutions at different saturation levels. Light propagation effects noted during these measurements-including the influence of vessel density and depth on Hb concentration and saturation estimates, and the effect of wavelength on vessel visualization depth-were evaluated. Overall, our findings indicated that 3-D-printed biomimetic phantoms hold significant potential as realistic and practical tools for elucidating light-tissue interactions and characterizing biophotonic system performance.

  4. Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations

    NASA Astrophysics Data System (ADS)

    Franco, B.; Hendrick, F.; Van Roozendael, M.; Müller, J.-F.; Stavrakou, T.; Marais, E. A.; Bovy, B.; Bader, W.; Fayt, C.; Hermans, C.; Lejeune, B.; Pinardi, G.; Servais, C.; Mahieu, E.

    2015-04-01

    As an ubiquitous product of the oxidation of many volatile organic compounds (VOCs), formaldehyde (HCHO) plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. In this study, HCHO profiles have been successfully retrieved from ground-based Fourier transform infrared (FTIR) solar spectra and UV-visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) scans recorded during the July 2010-December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.). Analysis of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art chemical transport models (CTMs), GEOS-Chem and IMAGES v2, have been compared to FTIR total columns and MAX-DOAS 3.6-8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTM outputs as the intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval above the Jungfraujoch station. Finally, tests have revealed that the updated IR parameters from the HITRAN 2012 database have a cumulative effect and significantly decrease the retrieved HCHO columns with respect to the use of the HITRAN 2008 compilation.

  5. A Portable Ground-Based Atmospheric Monitoring System (PGAMS) for the Calibration and Validation of Atmospheric Correction Algorithms Applied to Aircraft and Satellite Images

    NASA Technical Reports Server (NTRS)

    Schiller, Stephen; Luvall, Jeffrey C.; Rickman, Doug L.; Arnold, James E. (Technical Monitor)

    2000-01-01

    Detecting changes in the Earth's environment using satellite images of ocean and land surfaces must take into account atmospheric effects. As a result, major programs are underway to develop algorithms for image retrieval of atmospheric aerosol properties and atmospheric correction. However, because of the temporal and spatial variability of atmospheric transmittance it is very difficult to model atmospheric effects and implement models in an operational mode. For this reason, simultaneous in situ ground measurements of atmospheric optical properties are vital to the development of accurate atmospheric correction techniques. Presented in this paper is a spectroradiometer system that provides an optimized set of surface measurements for the calibration and validation of atmospheric correction algorithms. The Portable Ground-based Atmospheric Monitoring System (PGAMS) obtains a comprehensive series of in situ irradiance, radiance, and reflectance measurements for the calibration of atmospheric correction algorithms applied to multispectral. and hyperspectral images. The observations include: total downwelling irradiance, diffuse sky irradiance, direct solar irradiance, path radiance in the direction of the north celestial pole, path radiance in the direction of the overflying satellite, almucantar scans of path radiance, full sky radiance maps, and surface reflectance. Each of these parameters are recorded over a wavelength range from 350 to 1050 nm in 512 channels. The system is fast, with the potential to acquire the complete set of observations in only 8 to 10 minutes depending on the selected spatial resolution of the sky path radiance measurements

  6. A prototype tap test imaging system: Initial field test results

    NASA Astrophysics Data System (ADS)

    Peters, J. J.; Barnard, D. J.; Hudelson, N. A.; Simpson, T. S.; Hsu, D. K.

    2000-05-01

    This paper describes a simple, field-worthy tap test imaging system that gives quantitative information about the size, shape, and severity of defects and damages. The system consists of an accelerometer, electronic circuits for conditioning the signal and measuring the impact duration, a laptop PC and data acquisition and processing software. The images are generated manually by tapping on a grid printed on a plastic sheet laid over the part's surface. A mechanized scanner is currently under development. The prototype has produced images for a variety of aircraft composite and metal honeycomb structures containing flaws, damages, and repairs. Images of the local contact stiffness, deduced from the impact duration using a spring model, revealed quantitatively the stiffness reduction due to flaws and damages, as well as the stiffness enhancement due to substructures. The system has been field tested on commercial and military aircraft as well as rotor blades and engine decks on helicopters. Field test results will be shown and the operation of the system will be demonstrated.—This material is based upon work supported by the Federal Aviation Administration under Contract #DTFA03-98-D-00008, Delivery Order No. IA016 and performed at Iowa State University's Center for NDE as part of the Center for Aviation Systems Reliability program.

  7. Ground-based and orbital off-axis aspherized grating imager-spectrographs: ISARD-OMP and OSIRIS-ODIN

    NASA Astrophysics Data System (ADS)

    Lemaitre, Gerard R.; Richardson, Eric H.

    1998-07-01

    Progress in Active Optics Methods has led to the invention and production of blazed aspherical gratings. These developments use jointly 'vase form' submasters and a two-stage replication technique. It has been shown that the use of aspherized gratings greatly minimizes the number of optical surfaces. This improves the optical throughput of astronomical spectrographs and has a capability of correcting camera mirror aberrations up to f/1.2. With respect to refractive designs, the full achromaticity in correcting mirror aberrations by constant line spacing reflective gratings allows much broader spectral coverages -- hereafter [(lambda) (lambda) ] approximately equals 2 octaves. In addition, and also due to a full reflective design, such instruments provide quasi- constant spectral dispersions and are distortion free. These latter features increase the accuracy in the data reduction process (sky substraction, etc. ...), and are particularly convenient in the multi-aperture mode. Recent developments in this field are presented with imager-spectrograph ISARD, dedicated to the Cassegrain focus of the 2m Bernard Lyot Telescope at Pic-du-Midi Observatory for faint object studies in the optical domain [320 - 1200 nm], and with spectrograph OSIRIS, to be launched in a ODIN orbital mission in 1998 and built by the Canadian Space Agency for studies in the spectral range [295 - 800 nm].

  8. Thermospheric wind and temperature fields observed using two ground based all-sky imaging Fabry-Perot spectrometers in Antarctica

    NASA Astrophysics Data System (ADS)

    Conde, M.; Bristow, W. A.; Hampton, D. L.; Kosch, M. J.; Ishii, M.; Paxton, L. J.; Davies, T.

    2016-12-01

    During the austral summer of 2015-2016 two new all-sky imaging Fabry-Perot spectrometers were installed in Antarctica to measure wind and temperature fields in the lower and middle thermosphere, at heights spanning a range from approximately 110 to 240 km altitude. The instruments are located at McMurdo and South Pole stations, both of which are typically near the equatorward edge of the polar cap under quiet to moderate levels of activity. Automated nightly observations began in March (McMurdo) and April (South Pole) of 2016. The instruments record Doppler spectra of the thermospheric oxygen 558 nm green line and 630 nm red line emissions. They view the sky down to around 70 degrees zenith angle, with this field being divided in software into 115 sub-regions, each of which gives an independent measure of Doppler temperature and line-of-sight wind. Typical integration times are one to several minutes. Here we will present an overview of the results obtained during this first season, including both climatological averages and examples of data from individual days. The overall behavior is generally as expected, with winds blowing approximately antisunward at all local times. However substantial local perturbations about this mean flow occur frequently, and are seen to be collocated with regions of strong ion convection observed by the SuperDARN radar network, and with regions of bright aurora, as observed by the Fabry-Perot instruments themselves, and by the SSUSI instruments aboard the DMSP F16 to F18 satellites. F-region neutral temperatures recorded on most days are spatially uniform and slowly varying in time. However very significant spatial and temporal temperature variations are observed during times of geomagnetic disturbance. Wave activity is also very a very common feature of the observed wind fields. These results are morphologically quite different to the behavior seen by similar instruments located in the northern hemisphere auroral zone. Reasons for

  9. Initial tests of a prototype MRI-compatible PET imager

    NASA Astrophysics Data System (ADS)

    Raylman, Raymond R.; Majewski, Stan; Lemieux, Susan; Velan, S. Sendhil; Kross, Brain; Popov, Vladimir; Smith, Mark F.; Weisenberger, Andrew G.; Wojcik, Randy

    2006-12-01

    Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI, will allow the correlation of form with function. Our group (a collaboration of West Virginia University and Jefferson Lab) is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode with an active FOV of 5×5×4 cm 3. Each MRI-PET detector module consists of an array of LSO detector elements (2.5×2.5×15 mm 3) coupled through a long fiber optic light guide to a single Hamamatsu flat panel PSPMT. The fiber optic light guide is made of a glued assembly of 2 mm diameter acrylic fibers with a total length of 2.5 m. The use of a light guides allows the PSPMTs to be positioned outside the bore of the 3 T General Electric MRI scanner used in the tests. Photon attenuation in the light guides resulted in an energy resolution of ˜60% FWHM, interaction of the magnetic field with PSPMT further reduced energy resolution to ˜85% FWHM. Despite this effect, excellent multi-plane PET and MRI images of a simple disk phantom were acquired simultaneously. Future work includes improved light guides, optimized magnetic shielding for the PSPMTs, construction of specialized coils to permit high-resolution MRI imaging, and use of the system to perform simultaneous PET and MRI or MR-spectroscopy .

  10. Characteristics of puffing activity revealed by ground-based, thermal infrared imaging: the example of Stromboli Volcano (Italy)

    NASA Astrophysics Data System (ADS)

    Gaudin, Damien; Taddeucci, Jacopo; Scarlato, Piergiorgio; Harris, Andrew; Bombrun, Maxime; Del Bello, Elisabetta; Ricci, Tullio

    2017-03-01

    Puffing, i.e., the frequent (1 s ca.) release of small (0.1-10 m3), over-pressurized pockets of magmatic gases, is a typical feature of open-conduit basaltic volcanoes worldwide. Despite its non-trivial contribution to the degassing budget of these volcanoes and its recognized role in volcano monitoring, detection and metering tools for puffing are still limited. Taking advantage of the recent developments in high-speed thermal infrared imaging, we developed a specific processing algorithm to detect the emission of individual puffs and measure their duration, size, volume, and apparent temperature at the vent. As a test case, we applied our method at Stromboli Volcano (Italy), studying "snapshots" of 1 min collected in the years 2012, 2013, and 2014 at several vents. In all 3 years, puffing occurred simultaneously at three or more vents with variable features. At the scale of the single vent, a direct relationship links puff temperature and radius, suggesting that the apparent temperature is mostly a function of puff thickness, while the real gas temperature is constant for all puffs. Once released in the atmosphere, puffs dissipate in less than 20 m. On a broader scale, puffing activity is highly variable from vent to vent and year to year, with a link between average frequency, temperature, and volume from 136 puffs per minute, 600 K above ambient temperature, 0.1 m3, and the occasional ejection of pyroclasts to 20 puffs per minute, 3 K above ambient, 20 m3, and no pyroclasts. Frequent, small, hot puffs occur at random intervals, while as the frequency decreases and size increases, an increasingly longer minimum interval between puffs, up to 0.5 s, appears. These less frequent and smaller puffs also display a positive correlation between puff volume and the delay from the previous puff. Our results suggest an important role of shallow bubble coalescence in controlling puffing activity. The smaller and more frequent puffing at "hotter" vents is in agreement with

  11. A model for rotation and shape of Asteroid 9969 Braille from ground-based observations and images obtained during the deep space 1 (DS1) flyby

    USGS Publications Warehouse

    Oberst, J.; Mottola, S.; Di, Martino M.; Hicks, M.; Buratti, B.; Soderblom, L.; Thomas, N.

    2001-01-01

    Image data from the DS1 encounter with Asteroid 9969 Braille and data from a coordinated ground-based photometric observing campaign are combined to study the physical properties of this small Mars crosser. From telescope data the object's brightness was found to vary by up to 0.5 mag from night to night, with the most probable synodic rotational period being 226.4 ?? 1.3 h (9.4 days) and a mean lightcurve magnitude R(1, ?? = 24??) = 17.04 ?? 0.10. During the flyby of the spacecraft, two frame images from a range of approximately 13,500 km and phase angle 82.4??, which impose strong constraints on size, shape, and albedo of the object, were obtained. Using telescope and flyby data in combination, the asteroid is estimated to have a size of 2.1 ?? 1 ?? 1 km3 and shown to have photometric properties similar to the asteroid 4 Vesta, notably a comparably high albedo. The high albedo supports the notion (L. Soderblom et al. 1999, Bull. Am. Astron. Soc. 31,) that Braille is of the V or Q taxonomic type. ?? 2001 Academic Press.

  12. Ground based infrared astronomy

    NASA Technical Reports Server (NTRS)

    Jennings, D. E.

    1988-01-01

    Infrared spectroscopic instrumentation has been developed for ground-based measurements of astrophysical objects in the intermediate infrared. A conventional Michelson interferometer is limited for astronomical applications in the intermediate infrared by quantum noise fluctuations in the radiation form the source and/or background incident on the detector, and the multiplex advantage is no longer available. One feasible approach to recovering the multiplex advantage is post-dispersion. The infrared signal after passing through telescope and interferometer, is dispersed by a low resolution grating spectrometer onto an array of detectors. The feasibility of the post-dispersion system has been demonstrated with observations of astrophysical objects in the 5 and 10 micrometer atmospheric windows from ground-based telescopes. During FY87/88 the post-disperser was used at the Kitt Peak 4-meter telescope and McMath telescope with facility Fourier transform spectrometers. Jupiter, Saturn, Mars, and Venus were observed. On Jupiter, the resolution at 12 micrometer was 0.01/cm, considerably higher than had been acheived previously. The spectrum contains Jovian ethane and acetylene emission. Construction was begun on the large cryogenic grating spectrometer.

  13. The Infrared Imaging Spectrograph (IRIS) for TMT: prototyping of cryogenic compatible stage for the imager

    NASA Astrophysics Data System (ADS)

    Uraguchi, Fumihiro; Obuchi, Yoshiyuki; Ikenoue, Bungo; Saito, Sakae; Suzuki, Ryuji; Hayano, Yutaka

    2016-08-01

    The IRIS Imager requires opt-mechanical stages which are operable under vacuum and cryogenic environment. Also the stage for the IRIS Imager is required to survive for 10 years without maintenance. To achieve the development goal, we decided prototyping of a two axis stage with 80 mm clear aperture. The prototype was designed as a double-deck stage, upper rotary stage and lower linear stage. Most of components are selected to take advantage of heritage from existing astronomical instruments. In contrast, mechanical components with lubricants such as bearings, linear motion guides and ball screws were modified to survive cryogenic environment. The performance proving test was carried out to evaluate errors such as wobbling, rotary and linear positioning error. Also durability test under anticipated load condition has been conducted. In this article, we report the detail of mechanical design, fabrication, performance and durability of the prototype.

  14. Digital image capture and rapid prototyping of the maxillofacial defect.

    PubMed

    Sabol, Jennifer V; Grant, Gerald T; Liacouras, Peter; Rouse, Stephen

    2011-06-01

    In order to restore an extraoral maxillofacial defect, a moulage impression is commonly made with traditional impression materials. This technique has some disadvantages, including distortion of the site due to the weight of the impression material, changes in tissue location with modifications of the patient position, and the length of time and discomfort for the patient due to the impression procedure and materials used. The use of the commercially available 3dMDface™ System creates 3D images of soft tissues to form an anatomically accurate 3D surface image. Rapid prototyping converts the virtual designs from the 3dMDface™ System into a physical model by converting the data to a ZPrint (ZPR) CAD format file and a stereolithography (STL) file. The data, in conjunction with a Zprinter(®) 450 or a Stereolithography Apparatus (SLA), can be used to fabricate a model for prosthesis fabrication, without the disadvantages of the standard moulage technique. This article reviews this technique and how it can be applied to maxillofacial prosthetics. © 2011 by The American College of Prosthodontists.

  15. The prototype imaging motional Stark effect diagnostic for ASDEX upgrade.

    PubMed

    Ford, O P; Howard, J; Wolf, R C

    2015-09-01

    This paper presents the development and testing of the prototype Imaging Motional Stark-Effect (IMSE) diagnostic, designed for ASDEX upgrade. A detailed description of the core hardware, theory of operation, and application to complex MSE spectra are presented and analytical evaluation methods suitable for the required accuracy are developed. The diagnostic is tested with a MSE-like polarised spectrum to assess the accuracy of different modulation modes suggested in previous works. Each is found to have small systematic errors due to non-ideal effects of the components, which must be carefully examined. In particular, the effect of intrinsic contrast that results from imperfect parallelism of the birefringent plates is found to have a strong effect. Methods to mitigate and correct for this are discussed. With the necessary corrections and calibrations, the accuracy of polarisation orientation is shown to be within ±0.2°. The effect of finite ellipticity is examined and the possibility to measure this to an accuracy of ±2.0° is demonstrated. The system is shown to be insensitive to broadband polarised background light, temperature variations, and critically to variations in the details of the MSE spectrum.

  16. The Expanding Nebular Remnant of the Recurrent Nova RS Ophiuchi (2006). II. Modeling of Combined Hubble Space Telescope Imaging and Ground-based Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ribeiro, V. A. R. M.; Bode, M. F.; Darnley, M. J.; Harman, D. J.; Newsam, A. M.; O'Brien, T. J.; Bohigas, J.; Echevarría, J. M.; Bond, H. E.; Chavushyan, V. H.; Costero, R.; Coziol, R.; Evans, A.; Eyres, S. P. S.; León-Tavares, J.; Richer, M. G.; Tovmassian, G.; Starrfield, S.; Zharikov, S. V.

    2009-10-01

    We report Hubble Space Telescope (HST) imaging, obtained 155 and 449 days after the 2006 outburst of the recurrent nova RS Ophiuchi, together with ground-based spectroscopic observations, obtained from the Observatorio Astronómico Nacional en San Pedro Mártir, Baja California, México and at the Observatorio Astrofísico Guillermo Haro, at Cananea, Sonora, México. The observations at the first epoch were used as inputs to model the geometry and kinematic structure of the evolving RS Oph nebular remnant. We find that the modeled remnant comprises two distinct co-aligned bipolar components; a low-velocity, high-density innermost (hour glass) region and a more extended, high-velocity (dumbbell) structure. This overall structure is in agreement with that deduced from radio observations and optical interferometry at earlier epochs. We find that the asymmetry observed in the west lobe is an instrumental effect caused by the profile of the HST filter and hence demonstrate that this lobe is approaching the observer. We then conclude that the system has an inclination to the line of sight of 39+1°-10. This is in agreement with the inclination of the binary orbit and lends support to the proposal that this morphology is due to the interaction of the outburst ejecta with either an accretion disk around the central white dwarf and/or a pre-existing red giant wind that is significantly denser in the equatorial regions of the binary than at the poles. The second epoch HST observation was also modeled. However, as no spectra were taken at this epoch, it is more difficult to constrain any model. Nevertheless, we demonstrate that between the two HST epochs the outer dumbbell structure seems to have expanded linearly. For the central (hour glass) region, there may be evidence of deceleration, but it is harder to draw firm conclusions in this case.

  17. Ground-based photo monitoring

    Treesearch

    Frederick C. Hall

    2000-01-01

    Ground-based photo monitoring is repeat photography using ground-based cameras to document change in vegetation or soil. Assume those installing the photo location will not be the ones re-photographing it. This requires a protocol that includes: (1) a map to locate the monitoring area, (2) another map diagramming the photographic layout, (3) type and make of film such...

  18. Prototyping a Global Soft X-Ray Imaging Instrument for Heliophysics, Planetary Science, and Astrophysics Science

    NASA Technical Reports Server (NTRS)

    Collier, M. R.; Porter, F. S.; Sibeck, D. G.; Carter, J. A.; Chiao, M. P.; Chornay, D. J.; Cravens, T.; Galeazzi, M.; Keller, J. W.; Koutroumpa, D.; hide

    2012-01-01

    We describe current progress in the development of a prototype wide field-of-view soft X-ray imager that employs Lobstereye optics and targets heliophysics, planetary, and astrophysics science. The prototype will provide proof-of-concept for a future flight instrument capable of imaging the entire dayside magnetosheath from outside the magnetosphere. Such an instrument was proposed for the ESA AXIOM mission.

  19. Prototyping a Global Soft X-ray Imaging Instrument for Heliophysics, Planetary Science, and Astrophysics Science

    NASA Technical Reports Server (NTRS)

    Collier, Michael R.; Porter, F. Scott; Sibeck, David G.; Carter, Jenny A.; Chiao, Meng P.; Chornay, Dennis J.; Cravens, Thomas; Galeazzi, Massimiliano; Keller, John W.; Koutroumpa, Dimitra; Kuntz, Kip; Read, Any M.; Robertson, Ina P.; Sembay, Steve; Snowden, Steven; Thomas, Nick

    2012-01-01

    We describe current progress in the development of a prototype wide field-of-view soft X-ray imager that employs Lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The prototype will provide proof-of-concept for a future flight instrument capable of imaging the entire dayside magnetosheath from outside the magnetosphere. Such an instrument was proposed for the FSA AXIOM mission

  20. Modeling the imaging performance of prototype organic x-ray imagers

    SciTech Connect

    Blakesley, J. C.; Speller, R.

    2008-01-15

    A unified Monte Carlo and cascaded systems model for the simulation of active-matrix flat-panel imagers is presented. With few input parameters, the model simulated the imaging performance of previously measured flat-panel imagers with reasonable accuracy. The model is used to predict the properties of conceptual flat-panel imagers based on organic semiconductors on plastic substrates. The model suggests that significant improvements in resolution and detective quantum efficiency could be achieved by operating such a detector in a back-side illuminated configuration, or by employing two imaging arrays arranged face-to-face. The effect of semiconductor properties on the conceptual imagers is investigated. According to the model, a photodiode quantum efficiency of 25% and dark current of less than 100 pA mm{sup -2} would be satisfactory for a prototype imager, while a competitive imager would require a photodiode quantum efficiency of 40-50% with a dark current of less than 10 pA mm{sup -2} to be quantum limited over the radiographic exposure range.

  1. The COROT ground-based archive and access system

    NASA Astrophysics Data System (ADS)

    Solano, E.; González-Riestra, R.; Catala, C.; Baglin, A.

    2002-01-01

    A prototype of the COROT ground-based archive and access system is presented here. The system has been developed at LAEFF and it is based on the experience gained at Laboratorio de Astrofisica Espacial y Fisica Fundamental (LAEFF) with the INES (IUE Newly Extracted System) Archive.

  2. Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations

    NASA Astrophysics Data System (ADS)

    Franco, B.; Hendrick, F.; Van Roozendael, M.; Müller, J.-F.; Stavrakou, T.; Marais, E. A.; Bovy, B.; Bader, W.; Fayt, C.; Hermans, C.; Lejeune, B.; Pinardi, G.; Servais, C.; Mahieu, E.

    2014-10-01

    As a ubiquitous product of the oxidation of many Volatile Organic Compounds (VOCs), formaldehyde (HCHO) plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. In this study, HCHO profiles have been successfully retrieved from ground-based Fourier Transform Infrared (FTIR) solar spectra and UV-Visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) scans recorded during the July 2010-December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.). Analysis of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art Chemical Transport Models (CTMs), GEOS-Chem and IMAGESv2, have been compared to FTIR total columns and MAX-DOAS 3.6-8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTMs outputs as intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval above the Jungfraujoch station.

  3. A phantom study to characterize the imaging quality of a phase-contrast tomosynthesis prototype

    NASA Astrophysics Data System (ADS)

    Wu, Di; Ghani, Muhammad U.; Miao, Hui; Li, Yuhua; Chen, Wei R.; Wu, Xizeng; Liu, Hong

    2013-02-01

    This research is aimed at studying the advantages of an x-ray phase-contrast tomosynthesis prototype by using phantoms. A prototype system is assembled with a micro-focus x-ray source, a rotating stage and a computed radiography detector mounted on an optical rail. A custom designed bubble wrap phantom is used in experiments. Angular projection images are acquired from -20° to +20° with 2° interval. The in-plane slices are reconstructed. The feature area on the phantom is observed. The prototype system provides an intrinsic way to investigate the potential and imaging quality of a phase-contrast tomosynthesis imaging method. As the result, phase-contrast tomosynthesis imaging method is demonstrated for its advantages in avoiding structure noise and overlapping issues by comparing the results acquired by computed radiography and phase-contrast radiography.

  4. Convex optimization problem prototyping for image reconstruction in computed tomography with the Chambolle-Pock algorithm.

    PubMed

    Sidky, Emil Y; Jørgensen, Jakob H; Pan, Xiaochuan

    2012-05-21

    The primal-dual optimization algorithm developed in Chambolle and Pock (CP) (2011 J. Math. Imag. Vis. 40 1-26) is applied to various convex optimization problems of interest in computed tomography (CT) image reconstruction. This algorithm allows for rapid prototyping of optimization problems for the purpose of designing iterative image reconstruction algorithms for CT. The primal-dual algorithm is briefly summarized in this paper, and its potential for prototyping is demonstrated by explicitly deriving CP algorithm instances for many optimization problems relevant to CT. An example application modeling breast CT with low-intensity x-ray illumination is presented.

  5. Atmospheric Correction Prototype Algorithm for High Spatial Resolution Multispectral Earth Observing Imaging Systems

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary

    2006-01-01

    This viewgraph presentation reviews the creation of a prototype algorithm for atmospheric correction using high spatial resolution earth observing imaging systems. The objective of the work was to evaluate accuracy of a prototype algorithm that uses satellite-derived atmospheric products to generate scene reflectance maps for high spatial resolution (HSR) systems. This presentation focused on preliminary results of only the satellite-based atmospheric correction algorithm.

  6. Prototypical near-infrared projection system - A potential training system for image intensifier devices

    NASA Astrophysics Data System (ADS)

    Intano, Gabriel P.; Pedroni, Gena M.; Rusche, Gerald

    1989-03-01

    A prototype near-IR projection system has been developed for possible use as a supplemental night vision goggle training aid. The system uses a near-IR cathode ray tube, projection lens, and an optical cut-off filter to project daytime video in the 830-1000 nm range. The prototype system and its image intensifier devices are described. Results from training effectiveness research are presented and used to proposed possible modifications to the system.

  7. A Compton camera prototype for prompt gamma medical imaging

    NASA Astrophysics Data System (ADS)

    Thirolf, P. G.; Aldawood, S.; Böhmer, M.; Bortfeldt, J.; Castelhano, I.; Dedes, G.; Fiedler, F.; Gernhäuser, R.; Golnik, C.; Helmbrecht, S.; Hueso-González, F.; Kolff, H. v. d.; Kormoll, T.; Lang, C.; Liprandi, S.; Lutter, R.; Marinšek, T.; Maier, L.; Pausch, G.; Petzoldt, J.; Römer, K.; Schaart, D.; Parodi, K.

    2016-05-01

    Compton camera prototype for a position-sensitive detection of prompt γ rays from proton-induced nuclear reactions is being developed in Garching. The detector system allows to track the Comptonscattered electrons. The camera consists of a monolithic LaBr3:Ce scintillation absorber crystal, read out by a multi-anode PMT, preceded by a stacked array of 6 double-sided silicon strip detectors acting as scatterers. The LaBr3:Ce crystal has been characterized with radioactive sources. Online commissioning measurements were performed with a pulsed deuteron beam at the Garching Tandem accelerator and with a clinical proton beam at the OncoRay facility in Dresden. The determination of the interaction point of the photons in the monolithic crystal was investigated.

  8. CT imaging with a mobile C-arm prototype

    NASA Astrophysics Data System (ADS)

    Cheryauka, Arvi; Tubbs, David; Langille, Vinton; Kalya, Prabhanjana; Smith, Brady; Cherone, Rocco

    2008-03-01

    Mobile X-ray imagery is an omnipresent tool in conventional musculoskeletal and soft tissue applications. The next generation of mobile C-arm systems can provide clinicians of minimally-invasive surgery and pain management procedures with both real-time high-resolution fluoroscopy and intra-operative CT imaging modalities. In this study, we research two C-arm CT experimental system configurations and evaluate their imaging capabilities. In a non-destructive evaluation configuration, the X-ray Tube - Detector assembly is stationary while an imaging object is placed on a rotating table. In a medical imaging configuration, the C-arm gantry moves around the patient and the table. In our research setting, we connect the participating devices through a Mobile X-Ray Imaging Environment known as MOXIE. MOXIE is a set of software applications for internal research at GE Healthcare - Surgery and used to examine imaging performance of experimental systems. Anthropomorphic phantom volume renderings and orthogonal slices of reconstructed images are obtained and displayed. The experimental C-arm CT results show CT-like image quality that may be suitable for interventional procedures, real-time data management, and, therefore, have great potential for effective use on the clinical floor.

  9. Microwave Breast Imaging System Prototype with Integrated Numerical Characterization

    PubMed Central

    Haynes, Mark; Stang, John; Moghaddam, Mahta

    2012-01-01

    The increasing number of experimental microwave breast imaging systems and the need to properly model them have motivated our development of an integrated numerical characterization technique. We use Ansoft HFSS and a formalism we developed previously to numerically characterize an S-parameter- based breast imaging system and link it to an inverse scattering algorithm. We show successful reconstructions of simple test objects using synthetic and experimental data. We demonstrate the sensitivity of image reconstructions to knowledge of the background dielectric properties and show the limits of the current model. PMID:22481906

  10. Lung imaging fluorescence endoscope: development and experimental prototype

    NASA Astrophysics Data System (ADS)

    Palcic, Branko; Lam, Stephen; MacAulay, Calum E.; Hung, Jaclyn; Jaggi, Bruno; Radjinia, Massud; Pon, Alfred; Profio, A. E.

    1991-06-01

    A lung imaging fluorescence endoscope has been developed which can be used for detection and localization of early lung cancer. We exploited tissue autofluorescence alone or in combination with fluorescent tumor localizing drugs to create pseudo images which can clearly delineate the diseased sites from the surrounding normal tissues. With this technique it is possible to detect early lung cancer as well as pre-cancerous lesions of one to two millimeters in diameter and only a few cell layers thick.

  11. Ground-based photographic monitoring.

    Treesearch

    Frederick C. Hall

    2001-01-01

    Land management professionals (foresters, wildlife biologists, range managers, and land managers such as ranchers and forest land owners) often have need to evaluate their management activities. Photographic monitoring is a fast, simple, and effective way to determine if changes made to an area have been successful. Ground-based photo monitoring means using photographs...

  12. Musculoskeletal imaging with a prototype photon-counting detector.

    PubMed

    Gruber, M; Homolka, P; Chmeissani, M; Uffmann, M; Pretterklieber, M; Kainberger, F

    2012-01-01

    To test a digital imaging X-ray device based on the direct capture of X-ray photons with pixel detectors, which are coupled with photon-counting readout electronics. The chip consists of a matrix of 256 × 256 pixels with a pixel pitch of 55 μm. A monolithic image of 11.2 cm × 7 cm was obtained by the consecutive displacement approach. Images of embalmed anatomical specimens of eight human hands were obtained at four different dose levels (skin dose 2.4, 6, 12, 25 μGy) with the new detector, as well as with a flat-panel detector. The overall rating scores for the evaluated anatomical regions ranged from 5.23 at the lowest dose level, 6.32 at approximately 6 μGy, 6.70 at 12 μGy, to 6.99 at the highest dose level with the photon-counting system. The corresponding rating scores for the flat-panel detector were 3.84, 5.39, 6.64, and 7.34. When images obtained at the same dose were compared, the new system outperformed the conventional DR system at the two lowest dose levels. At the higher dose levels, there were no significant differences between the two systems. The photon-counting detector has great potential to obtain musculoskeletal images of excellent quality at very low dose levels.

  13. Convex optimization problem prototyping for image reconstruction in computed tomography with the Chambolle-Pock algorithm

    PubMed Central

    Sidky, Emil Y.; Jørgensen, Jakob H.; Pan, Xiaochuan

    2012-01-01

    The primal-dual optimization algorithm developed in Chambolle and Pock (CP), 2011 is applied to various convex optimization problems of interest in computed tomography (CT) image reconstruction. This algorithm allows for rapid prototyping of optimization problems for the purpose of designing iterative image reconstruction algorithms for CT. The primal-dual algorithm is briefly summarized in the article, and its potential for prototyping is demonstrated by explicitly deriving CP algorithm instances for many optimization problems relevant to CT. An example application modeling breast CT with low-intensity X-ray illumination is presented. PMID:22538474

  14. Prototypes for Content-Based Image Retrieval in Clinical Practice

    PubMed Central

    Depeursinge, Adrien; Fischer, Benedikt; Müller, Henning; Deserno, Thomas M

    2011-01-01

    Content-based image retrieval (CBIR) has been proposed as key technology for computer-aided diagnostics (CAD). This paper reviews the state of the art and future challenges in CBIR for CAD applied to clinical practice. We define applicability to clinical practice by having recently demonstrated the CBIR system on one of the CAD demonstration workshops held at international conferences, such as SPIE Medical Imaging, CARS, SIIM, RSNA, and IEEE ISBI. From 2009 to 2011, the programs of CADdemo@CARS and the CAD Demonstration Workshop at SPIE Medical Imaging were sought for the key word “retrieval” in the title. The systems identified were analyzed and compared according to the hierarchy of gaps for CBIR systems. In total, 70 software demonstrations were analyzed. 5 systems were identified meeting the criterions. The fields of application are (i) bone age assessment, (ii) bone fractures, (iii) interstitial lung diseases, and (iv) mammography. Bridging the particular gaps of semantics, feature extraction, feature structure, and evaluation have been addressed most frequently. In specific application domains, CBIR technology is available for clinical practice. While system development has mainly focused on bridging content and feature gaps, performance and usability have become increasingly important. The evaluation must be based on a larger set of reference data, and workflow integration must be achieved before CBIR-CAD is really established in clinical practice. PMID:21892374

  15. Prototypes for content-based image retrieval in clinical practice.

    PubMed

    Depeursinge, Adrien; Fischer, Benedikt; Müller, Henning; Deserno, Thomas M

    2011-01-01

    Content-based image retrieval (CBIR) has been proposed as key technology for computer-aided diagnostics (CAD). This paper reviews the state of the art and future challenges in CBIR for CAD applied to clinical practice.We define applicability to clinical practice by having recently demonstrated the CBIR system on one of the CAD demonstration workshops held at international conferences, such as SPIE Medical Imaging, CARS, SIIM, RSNA, and IEEE ISBI. From 2009 to 2011, the programs of CADdemo@CARS and the CAD Demonstration Workshop at SPIE Medical Imaging were sought for the key word "retrieval" in the title. The systems identified were analyzed and compared according to the hierarchy of gaps for CBIR systems.In total, 70 software demonstrations were analyzed. 5 systems were identified meeting the criterions. The fields of application are (i) bone age assessment, (ii) bone fractures, (iii) interstitial lung diseases, and (iv) mammography. Bridging the particular gaps of semantics, feature extraction, feature structure, and evaluation have been addressed most frequently.In specific application domains, CBIR technology is available for clinical practice. While system development has mainly focused on bridging content and feature gaps, performance and usability have become increasingly important. The evaluation must be based on a larger set of reference data, and workflow integration must be achieved before CBIR-CAD is really established in clinical practice.

  16. Development of a universal medical X-ray imaging phantom prototype.

    PubMed

    Groenewald, Annemari; Groenewald, Willem A

    2016-11-08

    Diagnostic X-ray imaging depends on the maintenance of image quality that allows for proper diagnosis of medical conditions. Maintenance of image quality requires quality assurance programs on the various X-ray modalities, which consist of pro-jection radiography (including mobile X-ray units), fluoroscopy, mammography, and computed tomography (CT) scanning. Currently a variety of modality-specific phantoms are used to perform quality assurance (QA) tests. These phantoms are not only expensive, but suitably trained personnel are needed to successfully use them and interpret the results. The question arose as to whether a single universal phantom could be designed and applied to all of the X-ray imaging modalities. A universal phantom would reduce initial procurement cost, possibly reduce the time spent on QA procedures and simplify training of staff on the single device. The aim of the study was to design and manufacture a prototype of a universal phantom, suitable for image quality assurance in general X-rays, fluoroscopy, mammography, and CT scanning. The universal phantom should be easy to use and would enable automatic data analysis, pass/fail reporting, and corrective action recommendation. In addition, a universal phantom would especially be of value in low-income countries where finances and human resources are limited. The design process included a thorough investigation of commercially available phantoms. Image quality parameters necessary for image quality assurance in the different X-ray imaging modalities were determined. Based on information obtained from the above-mentioned investigations, a prototype of a universal phantom was developed, keeping ease of use and reduced cost in mind. A variety of possible phantom housing and insert materials were investigated, considering physical properties, machinability, and cost. A three-dimensional computer model of the first phantom prototype was used to manufacture the prototype housing and inserts. Some of the

  17. Ground based silicon zoning program

    NASA Technical Reports Server (NTRS)

    Kern, E. L.

    1981-01-01

    The preparation of building flight hardware and carrying out experiments in space was investigated. The ground based investigation phase A/B of the experimental float zoning of silicon is outlined. The overall program goals, leading to recommending experiments to be done in phase C/D are spelled out. Thermophysical properties which must be accurately known to compare thermophysical models to experimental zoning of silicon are listed.

  18. Ground based materials science experiments

    NASA Technical Reports Server (NTRS)

    Meyer, M. B.; Johnston, J. C.; Glasgow, T. K.

    1988-01-01

    The facilities at the Microgravity Materials Science Laboratory (MMSL) at the Lewis Research Center, created to offer immediate and low-cost access to ground-based testing facilities for industrial, academic, and government researchers, are described. The equipment in the MMSL falls into three categories: (1) devices which emulate some aspect of low gravitational forces, (2) specialized capabilities for 1-g development and refinement of microgravity experiments, and (3) functional duplicates of flight hardware. Equipment diagrams are included.

  19. Ground based materials science experiments

    NASA Technical Reports Server (NTRS)

    Meyer, M. B.; Johnston, J. C.; Glasgow, T. K.

    1988-01-01

    The facilities at the Microgravity Materials Science Laboratory (MMSL) at the Lewis Research Center, created to offer immediate and low-cost access to ground-based testing facilities for industrial, academic, and government researchers, are described. The equipment in the MMSL falls into three categories: (1) devices which emulate some aspect of low gravitational forces, (2) specialized capabilities for 1-g development and refinement of microgravity experiments, and (3) functional duplicates of flight hardware. Equipment diagrams are included.

  20. Development of a universal medical X-ray imaging phantom prototype.

    PubMed

    Groenewald, Annemari; Groenewald, Willem A

    2016-11-01

    Diagnostic X-ray imaging depends on the maintenance of image quality that allows for proper diagnosis of medical conditions. Maintenance of image quality requires quality assurance programs on the various X-ray modalities, which consist of projection radiography (including mobile X-ray units), fluoroscopy, mammography, and computed tomography (CT) scanning. Currently a variety of modality-specific phantoms are used to perform quality assurance (QA) tests. These phantoms are not only expensive, but suitably trained personnel are needed to successfully use them and interpret the results. The question arose as to whether a single universal phantom could be designed and applied to all of the X-ray imaging modalities. A universal phantom would reduce initial procurement cost, possibly reduce the time spent on QA procedures and simplify training of staff on the single device. The aim of the study was to design and manufacture a prototype of a universal phantom, suitable for image quality assurance in general X-rays, fluoroscopy, mammography, and CT scanning. The universal phantom should be easy to use and would enable automatic data analysis, pass/fail reporting, and corrective action recommendation. In addition, a universal phantom would especially be of value in low-income countries where finances and human resources are limited. The design process included a thorough investigation of commercially available phantoms. Image quality parameters necessary for image quality assurance in the different X-ray imaging modalities were determined. Based on information obtained from the above-mentioned investigations, a prototype of a universal phantom was developed, keeping ease of use and reduced cost in mind. A variety of possible phantom housing and insert materials were investigated, considering physical properties, machinability, and cost. A three-dimensional computer model of the first phantom prototype was used to manufacture the prototype housing and inserts. Some of the

  1. A prototype of radiation imaging detector using silicon strip sensors

    NASA Astrophysics Data System (ADS)

    Ryu, S.; Hyun, H. J.; Kah, D. H.; Kang, H. D.; Kim, H. J.; Kim, Kyeryung; Kim, Y. I.; Park, H.; Son, D. H.

    2008-06-01

    The aim of this work is to evaluate the performance of a strip sensor with a single photon counting data acquisition system based on VA1 readout chips to study the feasibility of a silicon microstrip detector for medical application. The sensor is an AC-coupled single-sided microstrip sensor and the active area of the sensor is 32.0 mm×32.0 mm with a thickness of 380 μm. The sensor has 64 readout strips with a pitch of 500 μm. The sensor was biased at 45 V and the experiment was performed at room temperature. Two silicon strip sensors were mounted perpendicularly one another to get two-dimensional position information with a 5 mm space gap. Two low noise analog ASICs, VA1 chips, were used for signal readout of the strip sensor. The assembly of sensors and readout electronics was housed in an Al light-tight box. A CsI(Tl) scintillation crystal and a 2-in. photomultiplier tube were used to trigger signal events. The data acquisition system was based on a 64 MHz FADC and control softwares for the PC-Linux platform. Imaging tests were performed by using a lead phantom with a 90Sr radioactive source and a 45 MeV proton beam at Korea Institute of Radiological and Medical Science in Seoul, respectively. Results of the S/ N ratio measurement and phantom images are presented.

  2. Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner

    PubMed Central

    Kakinuma, Ryutaro; Moriyama, Noriyuki; Muramatsu, Yukio; Gomi, Shiho; Suzuki, Masahiro; Nagasawa, Hirobumi; Kusumoto, Masahiko; Aso, Tomohiko; Muramatsu, Yoshihisa; Tsuchida, Takaaki; Tsuta, Koji; Maeshima, Akiko Miyagi; Tochigi, Naobumi; Watanabe, Shun-ichi; Sugihara, Naoki; Tsukagoshi, Shinsuke; Saito, Yasuo; Kazama, Masahiro; Ashizawa, Kazuto; Awai, Kazuo; Honda, Osamu; Ishikawa, Hiroyuki; Koizumi, Naoya; Komoto, Daisuke; Moriya, Hiroshi; Oda, Seitaro; Oshiro, Yasuji; Yanagawa, Masahiro; Tomiyama, Noriyuki; Asamura, Hisao

    2015-01-01

    Purpose The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. Materials and Methods This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm x 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm x 16 or 0.5 mm x 64 detector-row CT scanner operating at 150 mAs. Images from both scanners were reconstructed at 0.1-mm intervals; the slice thickness was 0.25 mm for the U-HRCT scanner and 0.5 mm for the C-HRCT scanners. For both scanners, the display field of view was 80 mm. The image noise of each scanner was evaluated using a phantom. U-HRCT and C-HRCT images of 53 images selected from 37 lung nodules were then observed and graded using a 5-point score by 10 board-certified thoracic radiologists. The images were presented to the observers randomly and in a blinded manner. Results The image noise for U-HRCT (100.87 ± 0.51 Hounsfield units [HU]) was greater than that for C-HRCT (40.41 ± 0.52 HU; P < .0001). The image quality of U-HRCT was graded as superior to that of C-HRCT (P < .0001) for all of the following parameters that were examined: margins of subsolid and solid nodules, edges of solid components and pulmonary vessels in subsolid nodules, air bronchograms, pleural indentations, margins of pulmonary vessels, edges of bronchi, and interlobar fissures. Conclusion Despite a larger image noise, the prototype U-HRCT scanner had a significantly better image quality than the C-HRCT scanners. PMID:26352144

  3. Preliminary Performance of CdZnTe Imaging Detector Prototypes

    NASA Technical Reports Server (NTRS)

    Ramsey, B.; Sharma, D. P.; Meisner, J.; Gostilo, V.; Ivanov, V.; Loupilov, A.; Sokolov, A.; Sipila, H.

    1999-01-01

    The promise of good energy and spatial resolution coupled with high efficiency and near-room-temperature operation has fuelled a large International effort to develop Cadmium-Zinc-Telluride (CdZnTe) for the hard-x-ray region. We present here preliminary results from our development of small-pixel imaging arrays fabricated on 5x5x1-mm and 5x5x2-mm spectroscopy and discriminator-grade material. Each array has 16 (4x4) 0.65-mm gold readout pads on a 0.75-mm pitch, with each pad connected to a discrete preamplifier via a pulse-welded gold wire. Each array is mounted on a 3-stage Peltier cooler and housed in an ion-pump-evacuated housing which also contains a hybrid micro-assembly for the 16 channels of electronics. We have investigated the energy resolution and approximate photopeak efficiency for each pixel at several energies and have used an ultra-fine beam x-ray generator to probe the performance at the pixel boundaries. Both arrays gave similar results, and at an optimum temperature of -20 C we achieved between 2 and 3% FWHM energy resolution at 60 keV and around 15% at 5.9 keV. We found that all the charge was contained within 1 pixel until very close to the pixels edge, where it would start to be shared with its neighbor. Even between pixels, all the charge would be appropriately shared with no apparently loss of efficiency or resolution. Full details of these measurements will be presented, together with their implications for future imaging-spectroscopy applications.

  4. Preliminary Performance of CdZnTe Imaging Detector Prototypes

    NASA Technical Reports Server (NTRS)

    Ramsey, B.; Sharma, D. P.; Meisner, J.; Gostilo, V.; Ivanov, V.; Loupilov, A.; Sokolov, A.; Sipila, H.

    1999-01-01

    The promise of good energy and spatial resolution coupled with high efficiency and near-room-temperature operation has fuelled a large International effort to develop Cadmium-Zinc-Telluride (CdZnTe) for the hard-x-ray region. We present here preliminary results from our development of small-pixel imaging arrays fabricated on 5x5x1-mm and 5x5x2-mm spectroscopy and discriminator-grade material. Each array has 16 (4x4) 0.65-mm gold readout pads on a 0.75-mm pitch, with each pad connected to a discrete preamplifier via a pulse-welded gold wire. Each array is mounted on a 3-stage Peltier cooler and housed in an ion-pump-evacuated housing which also contains a hybrid micro-assembly for the 16 channels of electronics. We have investigated the energy resolution and approximate photopeak efficiency for each pixel at several energies and have used an ultra-fine beam x-ray generator to probe the performance at the pixel boundaries. Both arrays gave similar results, and at an optimum temperature of -20 C we achieved between 2 and 3% FWHM energy resolution at 60 keV and around 15% at 5.9 keV. We found that all the charge was contained within 1 pixel until very close to the pixels edge, where it would start to be shared with its neighbor. Even between pixels, all the charge would be appropriately shared with no apparently loss of efficiency or resolution. Full details of these measurements will be presented, together with their implications for future imaging-spectroscopy applications.

  5. First Images of a Three-Layer Compton Telescope Prototype for Treatment Monitoring in Hadron Therapy.

    PubMed

    Llosá, Gabriela; Trovato, Marco; Barrio, John; Etxebeste, Ane; Muñoz, Enrique; Lacasta, Carlos; Oliver, Josep F; Rafecas, Magdalena; Solaz, Carles; Solevi, Paola

    2016-01-01

    A Compton telescope for dose monitoring in hadron therapy is under development at IFIC. The system consists of three layers of LaBr3 crystals coupled to silicon photomultiplier arrays. (22)Na sources have been successfully imaged reconstructing the data with an ML-EM code. Calibration and temperature stabilization are necessary for the prototype operation at low coincidence rates. A spatial resolution of 7.8 mm FWHM has been obtained in the first imaging tests.

  6. First Images of a Three-Layer Compton Telescope Prototype for Treatment Monitoring in Hadron Therapy

    PubMed Central

    Llosá, Gabriela; Trovato, Marco; Barrio, John; Etxebeste, Ane; Muñoz, Enrique; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Solaz, Carles; Solevi, Paola

    2016-01-01

    A Compton telescope for dose monitoring in hadron therapy is under development at IFIC. The system consists of three layers of LaBr3 crystals coupled to silicon photomultiplier arrays. 22Na sources have been successfully imaged reconstructing the data with an ML-EM code. Calibration and temperature stabilization are necessary for the prototype operation at low coincidence rates. A spatial resolution of 7.8 mm FWHM has been obtained in the first imaging tests. PMID:26870693

  7. Study on spectrograph for ionosphere: a broadband imaging instrument prototype for far-ultraviolet

    NASA Astrophysics Data System (ADS)

    Yu, Lei; Wang, Shu-rong; Lin, Guan-yu

    2011-08-01

    Current research on space-based exploration for the ionosphere needs more advanced technologies. Because the spectral signals in the ionosphere distributing basically in the farultraviolet waveband are very weak. Usual spectrometer structures and detectors such as CCD can't receive enough information. Based on this principle of atmospheric sounding, the imaging spectrometer prototype for ionosphere detection application was designed to solve the problem. This prototype consists of the telescope and the imaging spectrometer. The simple structure and small number of mirrors can help higher transmission efficiency be achieved and weak signals detection be implemented. The telescope is an off-axis parabolic mirror and the spectrometer is a modified Czerny-Turner spectral imaging system. Modified Czerny-Turner spectrometer contains a spherical mirror, a fixed plane grating and a toroidal mirror. By adjusting the incident angle to the collimating mirror and using toroidal mirror, coma and astigmatism were corrected well. We also optimize distances between the grating to the focusing mirror and the focusing mirror to the image plane to improve disadvantages of traditional Czerny-Turner structure. Designed results demonstrate that aberrations are substantially corrected, and high image quality can be obtained in broad waveband. The photon counting Wedge-Strip-Anode detector with micro-channel planes as the receiving plane is accepted for the instrument prototype. The other photon counting 2-D detector responding well for weak light such as Cross-Delay line detector and MAMA detector can also be used for detection. The calibration and performances testing system is made of a vacuum system, a deuterium lamp, a monochrometer and the instrument prototype. Results obtained from the experiment show that the spectral resolution is 2.4 nm and the spatial resolution is 80 μm. The other calibration experiments are running. The technology of the spectrometer prototype is important

  8. Prototype system for proton beam range measurement based on gamma electron vertex imaging

    NASA Astrophysics Data System (ADS)

    Lee, Han Rim; Kim, Sung Hun; Park, Jong Hoon; Jung, Won Gyun; Lim, Hansang; Kim, Chan Hyeong

    2017-06-01

    In proton therapy, for both therapeutic effectiveness and patient safety, it is very important to accurately measure the proton dose distribution, especially the range of the proton beam. For this purpose, recently we proposed a new imaging method named gamma electron vertex imaging (GEVI), in which the prompt gammas emitting from the nuclear reactions of the proton beam in the patient are converted to electrons, and then the converted electrons are tracked to determine the vertices of the prompt gammas, thereby producing a 2D image of the vertices. In the present study, we developed a prototype GEVI system, including dedicated signal processing and data acquisition systems, which consists of a beryllium plate (= electron converter) to convert the prompt gammas to electrons, two double-sided silicon strip detectors (= hodoscopes) to determine the trajectories of those converted electrons, and a plastic scintillation detector (= calorimeter) to measure their kinetic energies. The system uses triple coincidence logic and multiple energy windows to select only the events from prompt gammas. The detectors of the prototype GEVI system were evaluated for electronic noise level, energy resolution, and time resolution. Finally, the imaging capability of the GEVI system was tested by imaging a 90Sr beta source, a 60Co gamma source, and a 45-MeV proton beam in a PMMA phantom. The overall results of the present study generally show that the prototype GEVI system can image the vertices of the prompt gammas produced by the proton nuclear interactions.

  9. First MR images obtained during megavoltage photon irradiation from a prototype integrated linac-MR system.

    PubMed

    Fallone, B G; Murray, B; Rathee, S; Stanescu, T; Steciw, S; Vidakovic, S; Blosser, E; Tymofichuk, D

    2009-06-01

    The authors report the first magnetic resonance (MR) images produced by their prototype MR system integrated with a radiation therapy source. The prototype consists of a 6 MV linac mounted onto the open end of a biplanar 0.2 T permanent MR system which has 27.9 cm pole-to-pole opening with flat gradients (40 mT/m) running under a TMX NRC console. The distance from the magnet isocenter to the linac target is 80 cm. The authors' design has resolved the mutual interferences between the two devices such that the MR magnetic field does not interfere with the trajectory of the electron in the linac waveguide, and the radiofrequency (RF) signals from each system do not interfere with the operation of the other system. Magnetic and RF shielding calculations were performed and confirmed with appropriate measurements. The prototype is currently on a fixed gantry; however, in the very near future, the linac and MR magnet will rotate in unison such that the linac is always aimed through the opening in the biplanar magnet. MR imaging was found to be fully operational during linac irradiation and proven by imaging a phantom with conventional gradient echo sequences. Except for small changes in SNR, MR images produced during irradiation were visually and quantitatively very similar to those taken with the linac turned off. This prototype system provides proof of concept that the design has decreased the mutual interferences sufficiently to allow the development of real-time MR-guided radiotherapy. Low field-strength systems (0.2-0.5 T) have been used clinically as diagnostic tools. The task of the linac-MR system is, however, to provide MR guidance to the radiotherapy beam. Therefore, the 0.2 T field strength would provide adequate image quality for this purpose and, with the addition of fast imaging techniques, has the potential to provide 4D soft-tissue visualization not presently available in image-guided radiotherapy systems. The authors' initial design incorporates a

  10. Image Analysis via Fuzzy-Reasoning Approach: Prototype Applications at NASA

    NASA Technical Reports Server (NTRS)

    Dominguez, Jesus A.; Klinko, Steven J.

    2004-01-01

    A set of imaging techniques based on Fuzzy Reasoning (FR) approach was built for NASA at Kennedy Space Center (KSC) to perform complex real-time visual-related safety prototype tasks, such as detection and tracking of moving Foreign Objects Debris (FOD) during the NASA Space Shuttle liftoff and visual anomaly detection on slidewires used in the emergency egress system for Space Shuttle at the launch pad. The system has also proved its prospective in enhancing X-ray images used to screen hard-covered items leading to a better visualization. The system capability was used as well during the imaging analysis of the Space Shuttle Columbia accident. These FR-based imaging techniques include novel proprietary adaptive image segmentation, image edge extraction, and image enhancement. Probabilistic Neural Network (PNN) scheme available from NeuroShell(TM) Classifier and optimized via Genetic Algorithm (GA) was also used along with this set of novel imaging techniques to add powerful learning and image classification capabilities. Prototype applications built using these techniques have received NASA Space Awards, including a Board Action Award, and are currently being filed for patents by NASA; they are being offered for commercialization through the Research Triangle Institute (RTI), an internationally recognized corporation in scientific research and technology development. Companies from different fields, including security, medical, text digitalization, and aerospace, are currently in the process of licensing these technologies from NASA.

  11. Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) for WFIRST/AFTA

    NASA Technical Reports Server (NTRS)

    Gong, Qian; McElwain, Michael; Greeley, Bradford; Grammer, Bryan; Marx, Catherine; Memarsadeghi, Nargess; Hilton, George; Perrin, Marshall; Sayson, Llop; Domingo, Jorge; hide

    2015-01-01

    Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) is a prototype lenslet array based integral field spectrometer (IFS) designed for high contrast imaging of extrasolar planets. PISCES will be used to advance the technology readiness of the high contrast IFS baselined on the Wide-Field InfraRed Survey TelescopeAstrophysics Focused Telescope Assets (WFIRSTAFTA) coronagraph instrument. PISCES will be integrated into the high contrast imaging testbed (HCIT) at the Jet Propulsion Laboratory and will work with both the Hybrid Lyot Coronagraph (HLC) and the Shaped Pupil Coronagraph (SPC). We will present the PISCES optical design, including the similarities and differences of lenslet based IFSs to normal spectrometers, the trade-off between a refractive design and reflective design, as well as the compatibility to upgrade from the current 1k x 1k detector array to 4k x 4k detector array. The optical analysis, alignment plan, and mechanical design of the instrument will be discussed.

  12. Using EO-1 Hyperion Images to Prototype Environmental Products for Hyspiri

    NASA Technical Reports Server (NTRS)

    Middleton, Elizabeth M.; Campbell, Petya K. E.; Ungar, Stephen G.; Ong, Lawrence; Zhang, Qingyuan; Huemmrich, K. Fred; Mandl, Daniel J.; Frye, Stuart W.

    2011-01-01

    In November 2010, the Earth Observing One (EO-1) Satellite Mission will successfully complete a decade of Earth imaging by its two unique instruments, the Hyperion and the Advanced Land Imager (ALI). Both instruments are serving as prototypes for new orbital sensors, and the EO-1 is a heritage platform for the upcoming German mission, EnMAP. We provide an overview of the mission's lifetime. We briefly describe calibration & validation activities and overview the technical and scientific accomplishments of this mission. Some examples of the Mission Science Office (MSO) products are provided, as is an example of a image collected for disaster monitoring.

  13. Using EO-1 Hyperion Images to Prototype Environmental Products for Hyspiri

    NASA Technical Reports Server (NTRS)

    Middleton, Elizabeth M.; Campbell, Petya K. E.; Ungar, Stephen G.; Ong, Lawrence; Zhang, Qingyuan; Huemmrich, K. Fred; Mandl, Daniel J.; Frye, Stuart W.

    2011-01-01

    In November 2010, the Earth Observing One (EO-1) Satellite Mission will successfully complete a decade of Earth imaging by its two unique instruments, the Hyperion and the Advanced Land Imager (ALI). Both instruments are serving as prototypes for new orbital sensors, and the EO-1 is a heritage platform for the upcoming German mission, EnMAP. We provide an overview of the mission's lifetime. We briefly describe calibration & validation activities and overview the technical and scientific accomplishments of this mission. Some examples of the Mission Science Office (MSO) products are provided, as is an example of a image collected for disaster monitoring.

  14. Ground-based IRCM testing

    NASA Astrophysics Data System (ADS)

    Greer, Derek; Owen, Mark

    2010-04-01

    Recent advances in the ability to perform comprehensive ground based Infrared Countermeasure (IRCM) testing have the capability to fill the Test and Evaluation (T&E) gaps for existing and future weapons system acquisition. IRCM testing has historically been dominated and in a manner limited by expensive live fire testing requirements. While live fire testing is a vital part of IRCM T&E, next generation technological developments now enable closed-loop, ground-based IRCM testing to provide valuable complementary test data at a much lower cost. The high cost and limited assets that have prevented live fire and flight testing from providing a thorough hardware based data set required for previous T&E analysis is no longer an issue. In the past, traditional physics based digital system model (DSM) analysis has been utilized to augment the IRCM data sets to make them statistically significant. While DSM is a useful tool in the development of IRCM systems, the newly developed installed system testing utilizing a hardware-in-the-loop construct provides for an enhanced level of fidelity and assurance that the systems will meet the warfighter's needs. The goal of the newly developed test technologies is to develop a statistical significant data set utilizing hardware-in-the-loop at a significantly lower cost than historical methods.

  15. Validation and understanding of Moderate Resolution Imaging Spectroradiometer aerosol products (C5) using ground-based measurements from the handheld Sun photometer network in China

    Treesearch

    Zhanqing Li; Feng Niu; Kwon-Ho Lee; Jinyuan Xin; Wei Min Hao; Bryce L. Nordgren; Yuesi Wang; Pucai Wang

    2007-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) currently provides the most extensive aerosol retrievals on a global basis, but validation is limited to a small number of ground stations. This study presents a comprehensive evaluation of Collection 4 and 5 MODIS aerosol products using ground measurements from the Chinese Sun Hazemeter Network (CSHNET). The...

  16. Design of a prototype tri-electrode ion-chamber for megavoltage X-ray imaging

    NASA Astrophysics Data System (ADS)

    Samant, Sanjiv S.; Gopal, Arun; Jain, Jinesh; Xia, Junyi; DiBianca, Frank A.

    2007-04-01

    High-energy (megavoltage) X-ray imaging is widely used in industry (e.g., aerospace, construction, material sciences) as well as in health care (radiation therapy). One of the fundamental problems with megavoltage imaging is poor contrast and spatial resolution in the detected images due to the dominance of Compton scattering at megavoltage X-ray energies. Therefore, although megavoltage X-rays can be used to image highly attenuating objects that cannot be imaged at kilovoltage energies, the former does not provide the high image quality that is associated with the latter. A high contrast and spatial resolution detector for high-energy X-ray fields called the kinestatic charge detector (KCD) is presented here. The KCD is a tri-electrode ion-chamber based on highly pressurized noble gas. The KCD operates in conjunction with a strip-collimated X-ray beam (for high scatter rejection) to scan across the imaging field. Its thick detector design and unique operating principle provides enhanced charge signal integration for high quality imaging (quantum efficiency ˜50%) despite the unfavorable implications of high-energy X-ray interactions on image quality. The proposed design for a large-field prototype KCD includes a cylindrical pressure chamber along with 576 signal-collecting electrodes capable of resolving at 2 mm -1. The collecting electrodes are routed out of the chamber through the flat end-cap, thereby optimizing the mechanical strength of the chamber. This article highlights the simplified design of the chamber using minimal components for simple assembly. In addition, fundamental imaging measurements and estimates of ion recombination that were performed on a proof-of-principle test chamber are presented. The imaging performance of the prototype KCD was found to be an order-of-magnitude greater than commercial phosphor screen based flat-panel systems, demonstrating the potential for high-quality megavoltage imaging for a variety of industrial applications.

  17. CIMIDx: Prototype for a Cloud-Based System to Support Intelligent Medical Image Diagnosis With Efficiency.

    PubMed

    Bhavani, Selvaraj Rani; Senthilkumar, Jagatheesan; Chilambuchelvan, Arul Gnanaprakasam; Manjula, Dhanabalachandran; Krishnamoorthy, Ramasamy; Kannan, Arputharaj

    2015-03-27

    The Internet has greatly enhanced health care, helping patients stay up-to-date on medical issues and general knowledge. Many cancer patients use the Internet for cancer diagnosis and related information. Recently, cloud computing has emerged as a new way of delivering health services but currently, there is no generic and fully automated cloud-based self-management intervention for breast cancer patients, as practical guidelines are lacking. We investigated the prevalence and predictors of cloud use for medical diagnosis among women with breast cancer to gain insight into meaningful usage parameters to evaluate the use of generic, fully automated cloud-based self-intervention, by assessing how breast cancer survivors use a generic self-management model. The goal of this study was implemented and evaluated with a new prototype called "CIMIDx", based on representative association rules that support the diagnosis of medical images (mammograms). The proposed Cloud-Based System Support Intelligent Medical Image Diagnosis (CIMIDx) prototype includes two modules. The first is the design and development of the CIMIDx training and test cloud services. Deployed in the cloud, the prototype can be used for diagnosis and screening mammography by assessing the cancers detected, tumor sizes, histology, and stage of classification accuracy. To analyze the prototype's classification accuracy, we conducted an experiment with data provided by clients. Second, by monitoring cloud server requests, the CIMIDx usage statistics were recorded for the cloud-based self-intervention groups. We conducted an evaluation of the CIMIDx cloud service usage, in which browsing functionalities were evaluated from the end-user's perspective. We performed several experiments to validate the CIMIDx prototype for breast health issues. The first set of experiments evaluated the diagnostic performance of the CIMIDx framework. We collected medical information from 150 breast cancer survivors from hospitals

  18. First Results in the Development of a Compton Probe Prototype for Prostate Imaging

    NASA Astrophysics Data System (ADS)

    Llosá, G.

    2004-07-01

    Compton imaging offers the possibility to improve significantly prostate imaging. Current radiotracer techniques, such as PET, SPECT or planar scintigraphy, suffer from photon attenuation in the tissue, poor resolution or low efficiency. The development of a Compton probe employing silicon as scatter detector makes possible to obtain a considerable benefit over present instrumentation. Electronic collimation overcomes the resolution-efficiency tradeoff imposed by mechanical collimators, and due to its near field operation, both high resolution and high counting efficiency can be achieved. Silicon pad sensors and low noise electronics are being optimized for this application. A Compton probe prototype has been developed, proving its viability and enabling further steps towards the construction of a clinical prototype.

  19. Thermal surveillance of Cascade Range volcanoes using ERTS-1 multispectral scanner, aircraft imaging systems, and ground-based data communication platforms

    NASA Technical Reports Server (NTRS)

    Friedman, J. D.; Frank, D. G.; Preble, D.; Painter, J. E.

    1973-01-01

    A combination of infrared images depicting areas of thermal emission and ground calibration points have proved to be particularly useful in plotting time-dependent changes in surface temperatures and radiance and in delimiting areas of predominantly convective heat flow to the earth's surface in the Cascade Range and on Surtsey Volcano, Iceland. In an integrated experiment group using ERTS-1 multispectral scanner (MSS) and aircraft infrared imaging systems in conjunction with multiple thermistor arrays, volcano surface temperatures are relayed daily to Washington via data communication platform (DCP) transmitters and ERTS-1. ERTS-1 MSS imagery has revealed curvilinear structures at Lassen, the full extent of which have not been previously mapped. Interestingly, the major surface thermal manifestations at Lassen are aligned along these structures, particularly in the Warner Valley.

  20. Coordinated airglow observations between IMAP/VISI and a ground-based all-sky imager on concentric gravity wave in the mesopause

    NASA Astrophysics Data System (ADS)

    Perwitasari, S.; Sakanoi, T.; Yamazaki, A.; Otsuka, Y.; Hozumi, Y.; Akiya, Y.; Saito, A.; Shiokawa, K.; Kawamura, S.

    2015-11-01

    We present a study of concentric gravity waves (CGWs) event from the coordinated observation between Ionosphere, Mesosphere, upper Atmosphere, and Plasmasphere mapping (IMAP)/Visible and near-Infrared Spectral Imager (VISI), all-sky camera at Rikubetsu, Multi-functional Transport Satellite (MTSAT), Tropical Rainfall Measuring Mission, and MF radar at Wakkanai combined with Modern-Era Retrospective Analysis for Research and Application data. IMAP/VISI is the first space-based imager that capable of imaging the airglow in the mesosphere and lower thermosphere region in the nadir-looking direction. Therefore, it has a unique ability to observe a great extend of CGWs propagation. Arc-like shaped, part of CGWs pattern was observed around the mesopause (~95 km) in the O2 762 nm airglow emission obtained by IMAP/VISI at 1204 UT on 18 October 2012. Similar patterns were also observed by the all-sky imager at Rikubetsu (43.5°N, 143.8°E) in OI 557.7 nm and OH band airglow emissions from ~1100 to 1200 UT. Horizontal wavelengths of the observed small-scale gravity waves are ~50 km (OH band and OI 557.7 nm) and ~67 km (O2 762 nm). The source is suggested to be a deep convective activity over Honshu Island which likely was an enhanced convective activity related to a typhoon in the south of Japan. The data showed that the CGWs could propagate up to ~1400-1500 km horizontally from the source to the mesopause but not farther away. Using atmospheric temperature profiles obtained by Thermospheric Ionosphere Mesosphere Energetics Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry, we conclude that this long-distance propagation of the waves could be caused by thermal duct in the middle atmosphere. The arc-like shaped instead of full circle pattern points out that the wind filtering effect is significant for the particular direction of wave propagation.

  1. Design and Imaging of Ground-Based Multiple-Input Multiple-Output Synthetic Aperture Radar (MIMO SAR) with Non-Collinear Arrays.

    PubMed

    Hu, Cheng; Wang, Jingyang; Tian, Weiming; Zeng, Tao; Wang, Rui

    2017-03-15

    Multiple-Input Multiple-Output (MIMO) radar provides much more flexibility than the traditional radar thanks to its ability to realize far more observation channels than the actual number of transmit and receive (T/R) elements. In designing the MIMO imaging radar arrays, the commonly used virtual array theory generally assumes that all elements are on the same line. However, due to the physical size of the antennas and coupling effect between T/R elements, a certain height difference between T/R arrays is essential, which will result in the defocusing of edge points of the scene. On the other hand, the virtual array theory implies far-field approximation. Therefore, with a MIMO array designed by this theory, there will exist inevitable high grating lobes in the imaging results of near-field edge points of the scene. To tackle these problems, this paper derives the relationship between target's point spread function (PSF) and pattern of T/R arrays, by which the design criterion is presented for near-field imaging MIMO arrays. Firstly, the proper height between T/R arrays is designed to focus the near-field edge points well. Secondly, the far-field array is modified to suppress the grating lobes in the near-field area. Finally, the validity of the proposed methods is verified by two simulations and an experiment.

  2. Design and Imaging of Ground-Based Multiple-Input Multiple-Output Synthetic Aperture Radar (MIMO SAR) with Non-Collinear Arrays

    PubMed Central

    Hu, Cheng; Wang, Jingyang; Tian, Weiming; Zeng, Tao; Wang, Rui

    2017-01-01

    Multiple-Input Multiple-Output (MIMO) radar provides much more flexibility than the traditional radar thanks to its ability to realize far more observation channels than the actual number of transmit and receive (T/R) elements. In designing the MIMO imaging radar arrays, the commonly used virtual array theory generally assumes that all elements are on the same line. However, due to the physical size of the antennas and coupling effect between T/R elements, a certain height difference between T/R arrays is essential, which will result in the defocusing of edge points of the scene. On the other hand, the virtual array theory implies far-field approximation. Therefore, with a MIMO array designed by this theory, there will exist inevitable high grating lobes in the imaging results of near-field edge points of the scene. To tackle these problems, this paper derives the relationship between target’s point spread function (PSF) and pattern of T/R arrays, by which the design criterion is presented for near-field imaging MIMO arrays. Firstly, the proper height between T/R arrays is designed to focus the near-field edge points well. Secondly, the far-field array is modified to suppress the grating lobes in the near-field area. Finally, the validity of the proposed methods is verified by two simulations and an experiment. PMID:28294996

  3. Development of prototype shielded cervical intracavitary brachytherapy applicators compatible with CT and MR imaging

    SciTech Connect

    Price, Michael J.; Jackson, Edward F.; Gifford, Kent A.; Eifel, Patricia J.; Mourtada, Firas

    2009-12-15

    Purpose: Intracavitary brachytherapy (ICBT) is an integral part of the treatment regimen for cervical cancer and, generally, outcome in terms of local disease control and complications is a function of dose to the disease bed and critical structures, respectively. Therefore, it is paramount to accurately determine the dose given via ICBT to the tumor bed as well as critical structures. This is greatly facilitated through the use of advanced three-dimensional imaging modalities, such as CT and MR, to delineate critical and target structures with an ICBT applicator inserted in vivo. These methods are not possible when using a shielded applicator due to the image artifacts generated by interovoid shielding. The authors present two prototype shielded ICBT applicators that can be utilized for artifact-free CT image acquisition. They also investigate the MR amenability and dosimetry of a novel tungsten-alloy shielding material to extend the functionality of these devices. Methods: To accomplish artifact-free CT image acquisition, a ''step-and-shoot'' (S and S) methodology was utilized, which exploits the prototype applicators movable interovoid shielding. Both prototypes were placed in imaging phantoms that positioned the applicators in clinically applicable orientations. CT image sets were acquired of the prototype applicators as well as a shielded Fletcher-Williamson (sFW) ovoid. Artifacts present in each CT image set were qualitatively compared for each prototype applicator following the S and S methodology and the sFW. To test the novel tungsten-alloy shielding material's MR amenability, they constructed a phantom applicator that mimics the basic components of an ICBT ovoid. This phantom applicator positions the MR-compatible shields in orientations equivalent to the sFW bladder and rectal shields. MR images were acquired within a gadopentetate dimeglumine-doped water tank using standard pulse sequences and examined for artifacts. In addition, Monte Carlo simulations

  4. Development of prototype shielded cervical intracavitary brachytherapy applicators compatible with CT and MR imaging.

    PubMed

    Price, Michael J; Jackson, Edward F; Gifford, Kent A; Eifel, Patricia J; Mourtada, Firas

    2009-12-01

    Intracavitary brachytherapy (ICBT) is an integral part of the treatment regimen for cervical cancer and, generally, outcome in terms of local disease control and complications is a function of dose to the disease bed and critical structures, respectively. Therefore, it is paramount to accurately determine the dose given via ICBT to the tumor bed as well as critical structures. This is greatly facilitated through the use of advanced three-dimensional imaging modalities, such as CT and MR, to delineate critical and target structures with an ICBT applicator inserted in vivo. These methods are not possible when using a shielded applicator due to the image artifacts generated by interovoid shielding. The authors present two prototype shielded ICBT applicators that can be utilized for artifact-free CT image acquisition. They also investigate the MR amenability and dosimetry of a novel tungsten-alloy shielding material to extend the functionality of these devices. To accomplish artifact-free CT image acquisition, a "step-and-shoot" (S&S) methodology was utilized, which exploits the prototype applicators movable interovoid shielding. Both prototypes were placed in imaging phantoms that positioned the applicators in clinically applicable orientations. CT image sets were acquired of the prototype applicators as well as a shielded Fletcher-Williamson (sFW) ovoid. Artifacts present in each CT image set were qualitatively compared for each prototype applicator following the S&S methodology and the sFW. To test the novel tungsten-alloy shielding material's MR amenability, they constructed a phantom applicator that mimics the basic components of an ICBT ovoid. This phantom applicator positions the MR-compatible shields in orientations equivalent to the sFW bladder and rectal shields. MR images were acquired within a gadopentetate dimeglumine-doped water tank using standard pulse sequences and examined for artifacts. In addition, Monte Carlo simulations were performed to match the

  5. Analysis of the 2006 block-and-ash flow deposits of Merapi Volcano, Java, Indonesia, using high-spatial resolution IKONOS images and complementary ground based observations

    NASA Astrophysics Data System (ADS)

    Thouret, Jean-Claude; Gupta, Avijit; Liew, Soo Chin; Lube, Gert; Cronin, Shane J.; Surono, Dr

    2010-05-01

    On 16 June 2006 an overpass of IKONOS coincided with the emplacement of an active block-and-ash flow fed by a lava dome collapse event at Merapi Volcano (Java, Indonesia). This was the first satellite image recorded for a moving pyroclastic flow. The very high-spatial resolution data displayed the extent and impact of the pyroclastic deposits emplaced during and prior to, the day of image acquisition. This allowed a number of features associated with high-hazard block-and-ash flows emplaced in narrow, deep gorges to be mapped, interpreted and understood. The block-and-ash flow and surge deposits recognized in the Ikonos images include: (1) several channel-confined flow lobes and tongues in the box-shaped valley; (2) thin ash-cloud surge deposit and knocked-down trees in constricted areas on both slopes of the gorge; (3) fan-like over bank deposits on the Gendol-Tlogo interfluves from which flows were re-routed in the Tlogo secondary valley; (4) massive over bank lobes on the right bank from which flows devastated the village of Kaliadem 0.5 km from the main channel, a small part of this flow being re-channeled in the Opak secondary valley. The high-resolution IKONOS images also helped us to identify geomorphic obstacles that enabled flows to ramp and spill out from the sinuous channel, a process called flow avulsion. Importantly, the avulsion redirected flows to unexpected areas away from the main channel. In the case of Merapi we see that the presence of valley fill by previous deposits, bends and man-made dams influence the otherwise valley-guided course of the flows. Sadly, Sabo dams (built to ameliorate the effect of high sediment load streams) can actually cause block-and-ash flows to jump out of their containing channel and advance into sensitive areas. Very-high-spatial resolution satellite images are very useful for mapping and interpreting the distribution of freshly erupted volcanic deposits. IKONOS-type images with 1-m resolution provide opportunities to

  6. CIMIDx: Prototype for a Cloud-Based System to Support Intelligent Medical Image Diagnosis With Efficiency

    PubMed Central

    2015-01-01

    Background The Internet has greatly enhanced health care, helping patients stay up-to-date on medical issues and general knowledge. Many cancer patients use the Internet for cancer diagnosis and related information. Recently, cloud computing has emerged as a new way of delivering health services but currently, there is no generic and fully automated cloud-based self-management intervention for breast cancer patients, as practical guidelines are lacking. Objective We investigated the prevalence and predictors of cloud use for medical diagnosis among women with breast cancer to gain insight into meaningful usage parameters to evaluate the use of generic, fully automated cloud-based self-intervention, by assessing how breast cancer survivors use a generic self-management model. The goal of this study was implemented and evaluated with a new prototype called “CIMIDx”, based on representative association rules that support the diagnosis of medical images (mammograms). Methods The proposed Cloud-Based System Support Intelligent Medical Image Diagnosis (CIMIDx) prototype includes two modules. The first is the design and development of the CIMIDx training and test cloud services. Deployed in the cloud, the prototype can be used for diagnosis and screening mammography by assessing the cancers detected, tumor sizes, histology, and stage of classification accuracy. To analyze the prototype’s classification accuracy, we conducted an experiment with data provided by clients. Second, by monitoring cloud server requests, the CIMIDx usage statistics were recorded for the cloud-based self-intervention groups. We conducted an evaluation of the CIMIDx cloud service usage, in which browsing functionalities were evaluated from the end-user’s perspective. Results We performed several experiments to validate the CIMIDx prototype for breast health issues. The first set of experiments evaluated the diagnostic performance of the CIMIDx framework. We collected medical information

  7. Novel Applications of Rapid Prototyping in Gamma-ray and X-ray Imaging

    PubMed Central

    Miller, Brian W.; Moore, Jared W.; Gehm, Michael E.; Furenlid, Lars R.; Barrett, Harrison H.

    2010-01-01

    Advances in 3D rapid-prototyping printers, 3D modeling software, and casting techniques allow for the fabrication of cost-effective, custom components in gamma-ray and x-ray imaging systems. Applications extend to new fabrication methods for custom collimators, pinholes, calibration and resolution phantoms, mounting and shielding components, and imaging apertures. Details of the fabrication process for these components are presented, specifically the 3D printing process, cold casting with a tungsten epoxy, and lost-wax casting in platinum. PMID:22984341

  8. Study of a prototype high quantum efficiency thick scintillation crystal video-electronic portal imaging device.

    PubMed

    Samant, Sanjiv S; Gopal, Arun

    2006-08-01

    Image quality in portal imaging suffers significantly from the loss in contrast and spatial resolution that results from the excessive Compton scatter associated with megavoltage x rays. In addition, portal image quality is further reduced due to the poor quantum efficiency (QE) of current electronic portal imaging devices (EPIDs). Commercial video-camera-based EPIDs or VEPIDs that utilize a thin phosphor screen in conjunction with a metal buildup plate to convert the incident x rays to light suffer from reduced light production due to low QE (<2% for Eastman Kodak Lanex Fast-B). Flat-panel EPIDs that utilize the same luminescent screen along with an a-Si:H photodiode array provide improved image quality compared to VEPIDs, but they are expensive and can be susceptible to radiation damage to the peripheral electronics. In this article, we present a prototype VEPID system for high quality portal imaging at sub-monitor-unit (subMU) exposures based on a thick scintillation crystal (TSC) that acts as a high QE luminescent screen. The prototype TSC system utilizes a 12 mm thick transparent CsI(Tl) (thallium-activated cesium iodide) scintillator for QE=0.24, resulting in significantly higher light production compared to commercial phosphor screens. The 25 X 25 cm2 CsI(Tl) screen is coupled to a high spatial and contrast resolution Video-Optics plumbicon-tube camera system (1240 X 1024 pixels, 250 microm pixel width at isocenter, 12-bit ADC). As a proof-of-principle prototype, the TSC system with user-controlled camera target integration was adapted for use in an existing clinical gantry (Siemens BEAMVIEW(PLUS)) with the capability for online intratreatment fluoroscopy. Measurements of modulation transfer function (MTF) were conducted to characterize the TSC spatial resolution. The measured MTF along with measurements of the TSC noise power spectrum (NPS) were used to determine the system detective quantum efficiency (DQE). A theoretical expression of DQE(0) was developed

  9. Quality evaluation of pickling cucumbers using hyperspectral reflectance and transmittance imaging – Part 1. Development of a prototype

    USDA-ARS?s Scientific Manuscript database

    This paper reports on the development of a hyperspectral imaging prototype for real-time evaluation of external and internal quality of pickling cucumbers. The prototype consisted of a two-lane round belt conveyor, two illumination sources (one for reflectance and one for transmittance), and a line-...

  10. Near InfraRed Imaging Spectrograph (NIRIS) for ground-based mesospheric OH(6-2) and O2(0-1) intensity and temperature measurements

    NASA Astrophysics Data System (ADS)

    Singh, Ravindra P.; Pallamraju, Duggirala

    2017-08-01

    This paper describes the development of a new Near InfraRed Imaging Spectrograph (NIRIS) which is capable of simultaneous measurements of OH(6-2) Meinel and O2(0-1) atmospheric band nightglow emission intensities. In this spectrographic technique, rotational line ratios are obtained to derive temperatures corresponding to the emission altitudes of 87 and 94 km. NIRIS has been commissioned for continuous operation from optical aeronomy observatory, Gurushikhar, Mount Abu (24.6°N, 72.8°E) since January 2013. NIRIS uses a diffraction grating of 1200 lines mm^{-1} and 1024× 1024 pixels thermoelectrically cooled CCD camera and has a large field-of-view (FOV) of 80° along the slit orientation. The data analysis methodology adopted for the derivation of mesospheric temperatures is also described in detail. The observed NIRIS temperatures show good correspondence with satellite (SABER) derived temperatures and exhibit both tidal and gravity waves (GW) like features. From the time taken for phase propagation in the emission intensities between these two altitudes, vertical phase speed of gravity waves, cz, is calculated and along with the coherent GW time period `τ ', the vertical wavelength, λ z, is obtained. Using large FOV observations from NIRIS, the meridional wavelengths, λ y, are also calculated. We have used one year of data to study the possible cause(s) for the occurrences of mesospheric temperature inversions (MTIs). From the statistics obtained for 234 nights, it appears that in situ chemical heating is mainly responsible for the observed MTIs than the vertical propagation of the waves. Thus, this paper describes a novel near infrared imaging spectrograph, its working principle, data analysis method for deriving OH and O2 emission intensities and the corresponding rotational temperatures at these altitudes, derivation of gravity wave parameters (τ , cz, λ z, and λ y), and results on the statistical study of MTIs that exist in the earth's mesospheric

  11. The 3D scanner prototype utilize object profile imaging using line laser and octave software

    NASA Astrophysics Data System (ADS)

    Nurdini, Mugi; Manunggal, Trikarsa Tirtadwipa; Samsi, Agus

    2016-11-01

    Three-dimensional scanner or 3D Scanner is a device to reconstruct the real object into digital form on a computer. 3D Scanner is a technology that is being developed, especially in developed countries, where the current 3D Scanner devices is the advanced version with a very expensive prices. This study is basically a simple prototype of 3D Scanner with a very low investment costs. 3D Scanner prototype device consists of a webcam, a rotating desk system controlled by a stepper motor and Arduino UNO, and a line laser. Objects that limit the research is the object with same radius from its center point (object pivot). Scanning is performed by using object profile imaging by line laser which is then captured by the camera and processed by a computer (image processing) using Octave software. On each image acquisition, the scanned object on a rotating desk rotated by a certain degree, so for one full turn multiple images of a number of existing side are finally obtained. Then, the profile of the entire images is extracted in order to obtain digital object dimension. Digital dimension is calibrated by length standard, called gage block. Overall dimensions are then digitally reconstructed into a three-dimensional object. Validation of the scanned object reconstruction of the original object dimensions expressed as a percentage error. Based on the results of data validation, horizontal dimension error is about 5% to 23% and vertical dimension error is about +/- 3%.

  12. The mass of planet GJ 676A b from ground-based astrometry. A planetary system with two mature gas giants suitable for direct imaging

    NASA Astrophysics Data System (ADS)

    Sahlmann, J.; Lazorenko, P. F.; Ségransan, D.; Astudillo-Defru, N.; Bonfils, X.; Delfosse, X.; Forveille, T.; Hagelberg, J.; Lo Curto, G.; Pepe, F.; Queloz, D.; Udry, S.; Zimmerman, N. T.

    2016-11-01

    The star GJ 676A is an M0 dwarf hosting both gas-giant and super-Earth-type planets that were discovered with radial-velocity measurements. Using FORS2/VLT, we obtained position measurements of the star in the plane of the sky that tightly constrain its astrometric reflex motion caused by the super-Jupiter planet "b" in a 1052-day orbit. This allows us to determine the mass of this planet to be , which is 40% higher than the minimum mass inferred from the radial-velocity orbit. Using new HARPS radial-velocity measurements, we improve upon the orbital parameters of the inner low-mass planets "d" and "e" and we determine the orbital period of the outer giant planet "c" to be Pc = 7340 days under the assumption of a circular orbit. The preliminary minimum mass of planet "c" is Mcsini = 6.8 MJ with an upper limit of 39 MJ that we set using NACO/VLT high-contrast imaging. We also determine precise parallaxes and relative proper motions for both GJ 676A and its wide M3 companion GJ 676B. Although the system is probably quite mature, the masses and projected separations ( 0.̋1-0.̋4) of planets "b" and "c" make them promising targets for direct imaging with future instruments in space and on extremely large telescopes. In particular, we estimate that GJ 676A b and GJ 676A c are promising targets for directly detecting their reflected light with the WFIRST space mission. Our study demonstrates the synergy of radial-velocity and astrometric surveys that is necessary to identify the best targets for such a mission. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes 385.C-0416 (A,B), 086.C-0515(A), 089.C-0115(D,E), 072.C-0488(E), 180.C-0886(A), 183.C-0437(A), 085.C-0019(A), 091.C-0034(A), 095.C-0551(A), 096.C-0460(A).Full Table A.2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/595/A77

  13. Ground-based imaging spectroscopy of Venus: variability of HDO and SO2 between 2012 and 2017 and analysis of the thermal structure

    NASA Astrophysics Data System (ADS)

    Encrenaz, Therese; Greathouse, Thomas; Richter, Matthew; DeWitt, Curtis; Widemann, Thomas; Bezard, Bruno; Fouchet, Thierry; Atreya, Sushil; Sagawa, Hideo

    2017-04-01

    We have continued our monitoring of the lower mesosphere of Venus using high-resolution imaging spectroscopy, using the Texas Echelon Cross Echelle Spectrograph (TEXES) at the Infrared Telescope Facility (IRTF) at Maunakea Observatory (Hawaii). New observations have been performed in January 2016, December 2016, and (weather permitting) January 2017. We have mapped the abundances of SO2 and H2O (through HDO) over the H2SO4 cloud (at 7 μm) and within this cloud (at 19 μm) to study the short-term and long-term variability of the two species. HDO variations in time and space are moderate, while SO2 exhibits strong variations over the disk and on a timescale of a few hours (Encrenaz et al. AA 595, A74, 2016). The study of strong and weak CO2 lines, at 7 and 19 μm, also allows us to retrieve information on the thermal structure as a function of latitude and local hour. We will present an overview of our results on the variability of SO2 and HDO between 2012 and early 2017, and an analysis of the thermal structure at morning and evening terminators.

  14. Stream Discharge Measurement Using A Large-Scale Particle Image Velocimetry Prototype

    NASA Astrophysics Data System (ADS)

    Harpold, A. A.; Mostaghimi, S.

    2004-12-01

    Good water management is founded on accurate open-channel flow measurements. New technology for measuring discharge in streams and rivers has been pursued due to concerns about safety, accuracy, and costs of traditional methods. Large-Scale Particle Image Velocimetry (LSPIV) is an emerging technology for measuring discharge in streams and rivers. LSPIV is a system capable of measuring velocity fields by collecting and analyzing recorded images of the flow field. The LSPIV system tracks the movement of `tracers' through successive images using statistical correspondence. Cross-correlation algorithms divide the image into small interrogation areas; each producing one displacement vector. The surface velocity field can be used to estimate discharge based on the channel bathymetry. Use of LSPIV for flow measurements in low-order streams has several advantages. LSPIV is not as labor intensive and does not present the safety concerns of the conventional methods during high flow events. Another promise for LSPIV is remote monitoring applications, which could also reduce labor and data management costs. The scheme used in this study for the development of LSPIV follows a logical progression: assimilate current knowledge, develop methods and acquire equipment, conduct laboratory and field experiments for `proof-of-concept', and refine the methods to decrease costs and increase usability. A laboratory prototype was developed and tested in a flume, with good results. The experiment evaluated the LSPIV prototype and a Marsh-McBirney flow meter against the flume manometer. Several conclusions were made from the statistical analysis. The Froude number affects the accuracy of the Marsh-McBirney flow meter and the LSPIV prototype. Therefore, future applications may wish to use an adaptive method to determine input parameters based on flow conditions. The LSPIV prototype produced poor flow measurements at camera angles above a 30 degree oblique angle. Therefore, field applications

  15. GROUND-BASED Paα NARROW-BAND IMAGING OF LOCAL LUMINOUS INFRARED GALAXIES. I. STAR FORMATION RATES AND SURFACE DENSITIES

    SciTech Connect

    Tateuchi, Ken; Konishi, Masahiro; Motohara, Kentaro; Takahashi, Hidenori; Kato, Natsuko Mitani; Kitagawa, Yutaro; Todo, Soya; Toshikawa, Koji; Sako, Shigeyuki; Uchimoto, Yuka K.; Ohsawa, Ryou; Asano, Kentaro; Kamizuka, Takafumi; Nakamura, Tomohiko; Okada, Kazushi; Ita, Yoshifusa; Komugi, Shinya; Koshida, Shintaro; Manabe, Sho; Nakashima, Asami; and others

    2015-03-15

    Luminous infrared galaxies (LIRGs) are enshrouded by a large amount of dust produced by their active star formation, and it is difficult to measure their activity in optical wavelengths. We have carried out Paα narrow-band imaging observations of 38 nearby star forming galaxies including 33 LIRGs listed in the IRAS Revised Bright Galaxy Sample catalog with the Atacama Near InfraRed camera on the University of Tokyo Atacama Observatory (TAO) 1.0 m telescope (miniTAO). Star formation rates (SFRs) estimated from the Paα fluxes, corrected for dust extinction using the Balmer decrement method (typically A{sub V} ∼ 4.3 mag), show a good correlation with those from the bolometric infrared luminosity of the IRAS data within a scatter of 0.27 dex. This suggests that the correction of dust extinction for the Paα flux is sufficient in our sample. We measure the physical sizes and surface densities of infrared luminosities (Σ{sub L(IR)}) and the SFR (Σ{sub SFR}) of star forming regions for individual galaxies, and we find that most of the galaxies follow a sequence of local ultra-luminous or luminous infrared galaxies (U/LIRGs) on the L(IR)-Σ{sub L(IR)} and SFR-Σ{sub SFR} plane. We confirm that a transition of the sequence from normal galaxies to U/LIRGs is seen at L(IR) = 8 × 10{sup 10} L {sub ☉}. Also, we find that there is a large scatter in physical size, different from normal galaxies or ULIRGs. Considering the fact that most U/LIRGs are merging or interacting galaxies, this scatter may be caused by strong external factors or differences in their merging stages.

  16. Characterization of a prototype tabletop x-ray CT breast imaging system

    NASA Astrophysics Data System (ADS)

    O'Connor, J. Michael; Glick, Stephen J.; Gong, Xing; Didier, Clay; Mah'd, Mufeed

    2007-03-01

    Planar X-ray mammography is the standard medical imaging modality for the early detection of breast cancer. Based on advancements in digital flat-panel detector technology, dedicated x-ray computed tomography (CT) mammography is a modality under investigation that offers the potential for improved breast tumor imaging. We have implemented a prototype half cone-beam CT breast imaging system that utilizes an indirect flat-panel detector. This prototype can be used to explore and evaluate the effect of varying acquisition and reconstruction parameters on image quality. This report describes our system and characterizes the performance of the system through the analysis of Modulation Transfer Function (MTF) and Noise Power Spectrum (NPS). All CT reconstructions were made using Feldkamp's filtered backprojection algorithm. The 3D MTF was determined by the analysis of the plane spread function (PlSF) derived from the surface spread function (SSF) of reconstructed 6.3mm spheres. 3D NPS characterization was performed through the analysis of a 3D volume extracted from zero-mean CT noise of air reconstructions. The effect of varying locations on MTF and the effect of different Butterworth filter cutoff frequencies on NPS are reported. Finally, we present CT images of mastectomy excised breast tissue. Breast specimen images were acquired on our CTMS using an x-ray technique similar to the one used during performance characterization. Specimen images demonstrate the inherent CT capability to reduce the masking effect of anatomical noise. Both the quantitative system characterization and the breast specimen images continue to reinforce the hope that dedicated flat-panel detector, x-ray cone-beam CT will eventually provide enhanced breast cancer detection capability.

  17. Imaging the Algol triple system with the Navy Prototype Optical Interferometer

    NASA Astrophysics Data System (ADS)

    Zavala, Robert T.; Hummel, C. A.; Boboltz, D. A.; Ojha, R.; Shaffer, D. B.; Tycner, C.; Richards, M. T.; Hutter, D. J.

    2010-01-01

    With the Navy Prototype Optical Interferometer, the close binary pair in the triple system Algol was spatially resolved. We will present multi-epoch aperture synthesis images with milli-arcsecond resolution of the Algol triple system. The NPOI observed the Algol system at wavelengths between 5500 to 8500 Å with a resolution of approximately 25 Å. We will discuss the orbital solution, simultaneous observations with the VLBA and optical light-ratio results. The Navy Prototype Optical Interferometer is a joint project of the Naval Research Laboratory and the US Naval Observatory, in cooperation with Lowell Observatory, and is funded by the Office of Naval Research and the Oceanographer of the Navy. R.T.Z. is thankful for the support of a Fizeau Exchange Visitor Program grant from the European Interferometry Initiative which supported this work. This work was partially supported by National Science Foundation grant AST-0908440 to M.T.R.

  18. Knowledge-based visual image processing IDE model for algorithm and system rapid prototyping

    NASA Astrophysics Data System (ADS)

    Zhang, Biyin; Chen, Wei; Wang, Yuanbin

    2009-10-01

    A novel intelligent model for Image Processing (IP) research integrated development environment (IDE) is presented for rapid converting conceptual model of IP algorithm into computational model and program implementation. Considering psychology of IP and computer programming, this model presents a cycle model of IP research process and establishes an improved expert system prototype. Visualization approaches are introduced into visualizing three phases of IP development. An intelligent methodology is applied to reuse algorithms, graphical user interfaces (GUI) and data visualizing tools. Thus, researchers are allowed to fix more attention only on their own interest algorithm models. Experimental results show that the development based the new model enhances rapid algorithm prototype modeling with great efficiency and speed.

  19. Imaging of small children with a prototype for photon counting tomosynthesis

    NASA Astrophysics Data System (ADS)

    del Risco Norrlid, Lilián; Fredenberg, Erik; Hemmendorff, Magnus; Jackowski, Christian; Danielsson, Mats

    2009-02-01

    We present data on a first prototype for photon counting tomosynthesis imaging of small children, which we call photoncounting tomosynthesis (PCT). A photon counting detector can completely eliminate electronic noise, which makes it ideal for tomosynthesis because of the low dose in each projection. Another advantage is that the detector allows for energy sensitivity in later versions, which will further lower the radiation dose. In-plane resolution is high and has been measured to be 5 lp/mm, at least 4 times better than in CT, while the depth resolution was significantly lower than typical CT resolution. The image SNR decreased from 30 to 10 for a detail of 10 mm depth in increasing thickness of PMMA from 10 to 80 mm. The air kerma measured for PCT was 5.2 mGy, which leads to an organ dose to the brain of approximately 0.7 mGy. This dose is 96 % lower than a typical CT dose. PCT can be appealing for pediatric imaging since young children have an increased sensitivity to radiation induced cancers. We have acquired post mortem images of a newborn with the new device and with a state-of-the-art CT and compared the diagnostic information and dose levels of the two modalities. The results are promising but more work is needed to provide input to a next generation prototype that would be suitable for clinical trials.

  20. A prototype instrument for single pinhole small animal adaptive SPECT imaging

    PubMed Central

    Freed, Melanie; Kupinski, Matthew A.; Furenlid, Lars R.; Wilson, Donald W.; Barrett, Harrison H.

    2008-01-01

    The authors have designed and constructed a small-animal adaptive SPECT imaging system as a prototype for quantifying the potential benefit of adaptive SPECT imaging over the traditional fixed geometry approach. The optical design of the system is based on filling the detector with the region of interest for each viewing angle, maximizing the sensitivity, and optimizing the resolution in the projection images. Additional feedback rules for determining the optimal geometry of the system can be easily added to the existing control software. Preliminary data have been taken of a phantom with a small, hot, offset lesion in a flat background in both adaptive and fixed geometry modes. Comparison of the predicted system behavior with the actual system behavior is presented, along with recommendations for system improvements. PMID:18561667

  1. A prototype of mammography CADx scheme integrated to imaging quality evaluation techniques

    NASA Astrophysics Data System (ADS)

    Schiabel, Homero; Matheus, Bruno R. N.; Angelo, Michele F.; Patrocínio, Ana Claudia; Ventura, Liliane

    2011-03-01

    As all women over the age of 40 are recommended to perform mammographic exams every two years, the demands on radiologists to evaluate mammographic images in short periods of time has increased considerably. As a tool to improve quality and accelerate analysis CADe/Dx (computer-aided detection/diagnosis) schemes have been investigated, but very few complete CADe/Dx schemes have been developed and most are restricted to detection and not diagnosis. The existent ones usually are associated to specific mammographic equipment (usually DR), which makes them very expensive. So this paper describes a prototype of a complete mammography CADx scheme developed by our research group integrated to an imaging quality evaluation process. The basic structure consists of pre-processing modules based on image acquisition and digitization procedures (FFDM, CR or film + scanner), a segmentation tool to detect clustered microcalcifications and suspect masses and a classification scheme, which evaluates as the presence of microcalcifications clusters as well as possible malignant masses based on their contour. The aim is to provide enough information not only on the detected structures but also a pre-report with a BI-RADS classification. At this time the system is still lacking an interface integrating all the modules. Despite this, it is functional as a prototype for clinical practice testing, with results comparable to others reported in literature.

  2. The Java Image Science Toolkit (JIST) for rapid prototyping and publishing of neuroimaging software.

    PubMed

    Lucas, Blake C; Bogovic, John A; Carass, Aaron; Bazin, Pierre-Louis; Prince, Jerry L; Pham, Dzung L; Landman, Bennett A

    2010-03-01

    Non-invasive neuroimaging techniques enable extraordinarily sensitive and specific in vivo study of the structure, functional response and connectivity of biological mechanisms. With these advanced methods comes a heavy reliance on computer-based processing, analysis and interpretation. While the neuroimaging community has produced many excellent academic and commercial tool packages, new tools are often required to interpret new modalities and paradigms. Developing custom tools and ensuring interoperability with existing tools is a significant hurdle. To address these limitations, we present a new framework for algorithm development that implicitly ensures tool interoperability, generates graphical user interfaces, provides advanced batch processing tools, and, most importantly, requires minimal additional programming or computational overhead. Java-based rapid prototyping with this system is an efficient and practical approach to evaluate new algorithms since the proposed system ensures that rapidly constructed prototypes are actually fully-functional processing modules with support for multiple GUI's, a broad range of file formats, and distributed computation. Herein, we demonstrate MRI image processing with the proposed system for cortical surface extraction in large cross-sectional cohorts, provide a system for fully automated diffusion tensor image analysis, and illustrate how the system can be used as a simulation framework for the development of a new image analysis method. The system is released as open source under the Lesser GNU Public License (LGPL) through the Neuroimaging Informatics Tools and Resources Clearinghouse (NITRC).

  3. Studies of a prototype linear stationary x-ray source for tomosynthesis imaging

    NASA Astrophysics Data System (ADS)

    Schwoebel, P. R.; Boone, John M.; Shao, Joe

    2014-05-01

    A prototype linear x-ray source to implement stationary source-stationary detector tomosynthesis (TS) imaging has been studied. Potential applications include human breast and small animal imaging. The source is comprised of ten x-ray source elements each consisting of a field emission cathode, electrostatic lens, and target. The electrostatic lens and target are common to all elements. The source elements form x-ray focal spots with minimum diameters of 0.3-0.4 mm at electron beam currents of up to 40 mA with a beam voltage of 40 kV. The x-ray flux versus time was quantified from each source. X-ray bremsstrahlung spectra from tungsten targets were produced using electron beam energies from 35 to 50 keV. The half-value layer was measured to be 0.8, 0.9, and 1.0 mm, respectively, for the 35, 40, and 45 kV tube potentials using the tungsten target. The suppression of voltage breakdown events, particularly during source operation, and the use of a modified form of the standard cold-cathode geometry, enhanced source reliability. The prototype linear source was used to collect tomographic data sets of a mouse phantom using digital TS reconstruction methods and demonstrated a slice-sensitivity profile with a full-width-half-maximum of 1.3 mm. Lastly, preliminary studies of tomographic imaging of flow through the mouse phantom were performed.

  4. The Java Image Science Toolkit (JIST) for Rapid Prototyping and Publishing of Neuroimaging Software

    PubMed Central

    Lucas, Blake C.; Bogovic, John A.; Carass, Aaron; Bazin, Pierre-Louis; Prince, Jerry L.; Pham, Dzung

    2010-01-01

    Non-invasive neuroimaging techniques enable extraordinarily sensitive and specific in vivo study of the structure, functional response and connectivity of biological mechanisms. With these advanced methods comes a heavy reliance on computer-based processing, analysis and interpretation. While the neuroimaging community has produced many excellent academic and commercial tool packages, new tools are often required to interpret new modalities and paradigms. Developing custom tools and ensuring interoperability with existing tools is a significant hurdle. To address these limitations, we present a new framework for algorithm development that implicitly ensures tool interoperability, generates graphical user interfaces, provides advanced batch processing tools, and, most importantly, requires minimal additional programming or computational overhead. Java-based rapid prototyping with this system is an efficient and practical approach to evaluate new algorithms since the proposed system ensures that rapidly constructed prototypes are actually fully-functional processing modules with support for multiple GUI's, a broad range of file formats, and distributed computation. Herein, we demonstrate MRI image processing with the proposed system for cortical surface extraction in large cross-sectional cohorts, provide a system for fully automated diffusion tensor image analysis, and illustrate how the system can be used as a simulation framework for the development of a new image analysis method. The system is released as open source under the Lesser GNU Public License (LGPL) through the Neuroimaging Informatics Tools and Resources Clearinghouse (NITRC). PMID:20077162

  5. X-ray tube-based diffraction enhanced imaging prototype images of full-thickness breast specimens: reader study evaluation

    NASA Astrophysics Data System (ADS)

    Faulconer, L. S.; Parham, C.; Connor, D. J.; Koomen, M.; Kuzmiak, C.; Pavic, D.; Livasy, C. A.; Kim, E.; Zeng, D.; Cole, E. B.; Zhong, Z.; Pisano, E. D.

    2009-02-01

    Conventional mammographic image contrast is derived from x-ray absorption, resulting in breast structure visualization due to density gradients that attenuate radiation without distinction between transmitted and scattered or refracted x-rays. This leads to image blurring and contrast reduction, hindering the early detection of small or otherwise occult cancers. Diffraction enhanced imaging (DEI) allows for dramatically increased contrast with decreased radiation dose compared to conventional mammographic imaging due to monochromatic x-rays, its unique refraction-based contrast mechanism and excellent scatter rejection. However, a lingering drawback to the clinical translation of DEI has been the requirement for synchrotron radiation. Our laboratory developed a DEI prototype (DEI-PR) utilizing a readily available Tungsten xray tube source and traditional DEI crystal optics, providing soft tissue images at 60keV. To demonstrate the clinical utility of our DEI-PR, we acquired images of full-thickness human breast tissue specimens on synchrotron-based DEI, DEI-PR and digital mammography systems. A reader study was designed to allow unbiased assessment of system performance when analyzing three systems with dissimilar imaging parameters and requiring analysis of images unfamiliar to radiologists. A panel of expert radiologists evaluated lesion feature visibility and histopathology correlation after receiving training on the interpretation of refraction contrast mammographic images. Preliminary data analysis suggests that our DEI system performed roughly equivalently with the traditional DEI system, demonstrating a significant step toward clinical translation of this modality for breast cancer applications.

  6. Multi-anode microchannel arrays. [for use in ground-based and spaceborne telescopes

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.; Mount, G. H.; Bybee, R. L.

    1979-01-01

    The Multi-Anode Microchannel Arrays (MAMA's) are a family of photoelectric, photon-counting array detectors being developed for use in instruments on both ground-based and space-borne telescopes. These detectors combine high sensitivity and photometric stability with a high-resolution imaging capability. MAMA detectors can be operated in a windowless configuration at extreme-ultraviolet and soft X-ray wavelengths or in a sealed configuration at ultraviolet and visible wavelengths. Prototype MAMA detectors with up to 512 x 512 pixels are now being tested in the laboratory and telescope operation of a simple (10 x 10)-pixel visible-light detector has been initiated. The construction and modes-of-operation of the MAMA detectors are briefly described and performance data are presented.

  7. Ground-based imaging spectroscopy of Mars

    NASA Astrophysics Data System (ADS)

    Bailey, Jeremy; Chamberlain, Sarah; Walter, Malcolm; Crisp, David

    2004-03-01

    We describe here the preliminary results of observations obtained during the very favourable opposition of August 2003 using the UIST instrument on the United Kingdom Infrared Telescpe (UKIRT) on Mauna Kea, Hawaii. Infrared spectral scans of the disk were obtained at a range of near-IR wavelengths and resolving powers. The observations cover wavelengths, which include absorption features due to a range of potential surface minerals, H2O and CO2 ice, and atmospheric gases including CO2 and a number of trace gases. Such observations can be used to search for evidence of the past presence fo surface water, and to measure atmospheric properties.

  8. Highlights from Ground-Based O/IR Interferometers

    NASA Astrophysics Data System (ADS)

    Armstrong, J. Thomas; Creech-Eakman, M. J.; Akeson, R. L.; Bakker, E. J.; Hutter, D. J.; McAlister, H. A.; ten Brummelaar, T.; Townes, C. H.

    2009-01-01

    Ground-based optical/infrared long-baseline interferometry has continued to extend its capabilities in the U.S., where several existing facilites demonstrate its capabilites in a broad range of scientific applications. This poster presents brief overviews of the CHARA Array and the Infrared Spatial Interferometer (ISI) on Mt. Wilson, CA; the Palomar Testbed Interferometer (PTI) on Mt. Palomar, CA; the Navy Prototype Optical Interferometer (NPOI) located on Anderson Mesa near Flagstaff, AZ; and the Keck Interferometer (KI) on Mauna Kea, HI; as well as the Magdalena Ridge Observatory Interferometer (MROI) now under construction at the highest elevation of the Magdalena Mountains of New Mexico. The poster also includes pointers to a small fraction of the scientific results from U.S. interferometers. Recent scientific highlights range from stellar atmospheres (precise diameters, including G/K dwarfs; limb darkening; Cepheid pulsations) to circumstellar material (water detected in a protoplanetary disk; debris disks; Be star disks; warped circumbinary disks; dust shells) to orbits and stellar masses in double, triple, and quadruple systems, to images of stellar surfaces (rapid rotators such Altair), to name a few. While the great majority of results to date have focused on stellar astrophysics, the MROI strives to have sensitivity sufficient to access a number of AGN. Research with these independently operated facilities is sponsored by the California Institute of Technology and the Jet Propulsion Laboratory for PTI; the Oceanographer of the Navy and the Office of Naval Research for NPOI; the National Aeronautics and Space Administration for KI; the National Science Foundation and Georgia State University for the CHARA Array; and the Office of Naval Research, the National Science Foundation, and the Gordon and Betty Moore Foundation for ISI. Funding for MROI is administered through the Office of Naval Research.

  9. Science Highlights from Ground-Based O/IR Interferometers

    NASA Astrophysics Data System (ADS)

    McAlister, Harold A.; Akeson, R.; Armstrong, T.; Bakker, E.; Boden, A.; ten Brummelaar, T.; Creech-Eakman, M.; Hutter, D.

    2007-05-01

    Ground-based optical/infrared long-baseline interferometry has come of age in the U.S. where several existing or planned facilities have produced remarkable scientific results demonstrating the power of the technique within a broad range of scientific applications. This paper presents brief overviews of the following facilities: the Palomar Testbed Interferometer (PTI) on Mt. Palomar, CA; the Navy Prototype Optical Interferometer (NPOI) located on Anderson Mesa near Flagstaff, AZ; the Keck Interferometer (KI) on Mauna Kea, HI; and the CHARA Array on Mt. Wilson, CA. Also described is the Magdalena Ridge Observatory Interferometer (MROI) to be built at the highest elevation of the Magdalena Mountains of New Mexico. Example scientific highlights to date include: The first measurement of stellar rotational oblateness (Altair), the detection of Cepheid pulsations, and ultra-precise astrometry of binaries with PTI; the first six-telescope images (the triple system eta Virginis) and constraints on disk parameters of Be stars with NPOI; resolving the nucleus of NGC 4151 and probing the inner disk regions of YSOs with KI; and, the first direct detection of gravity darkening in single stars (Regulus), calibration of the Baade-Wesselink method for Cepheids, and the first direct measurement of the diameter of an exoplanet (the transit system HD 189733) using the CHARA Array. While the great majority of results to date have focused on stellar astrophysics, the MROI strives to have sensitivity sufficient to access a number of AGN. Research with these independently operated facilities is sponsored by the California Institute of Technology and the Jet Propulsion Laboratory for PTI; the U.S. Naval Observatory and the Naval Research Laboratory for NPOI; the National Aeronautics and Space Administration for KI; and, the National Science Foundation and Georgia State University for the CHARA Array. Funding for MROI is administered through the Office of Naval Research.

  10. Quantitative assessment of biophotonic imaging system performance with phantoms fabricated by rapid prototyping

    NASA Astrophysics Data System (ADS)

    Wang, Jianting; Coburn, James; Woolsey, Nicholas; Liang, Chia-Pin; Ramella-Roman, Jessica; Chen, Yu; Pfefer, Joshua

    2014-03-01

    In biophotonic imaging, turbid phantoms that are low-cost, biologically-relevant, and durable are desired for standardized performance assessment. Such phantoms often contain inclusions of varying depths and sizes in order to quantify key image quality characteristics such as penetration depth, sensitivity and contrast detectability. The emerging technique of rapid prototyping with three-dimensional (3D) printers provides a potentially revolutionary way to fabricate these structures. Towards this goal, we have characterized the optical properties and morphology of phantoms fabricated by two 3D printing approaches: thermosoftening and photopolymerization. Material optical properties were measured by spectrophotometry while the morphology of phantoms incorporating 0.2-1.0 mm diameter channels was studied by μCT, optical coherence tomography (OCT) and optical microscopy. A near-infrared absorbing dye and nanorods at several concentrations were injected into channels to evaluate detectability with a near-infrared hyperspectral reflectance imaging (HRI) system (650-1100 nm). Phantoms exhibited biologically-relevant scattering and low absorption across visible and near-infrared wavelengths. Although limitations in resolution were noted, channels with diameters of 0.4 mm or more could be reliably fabricated. The most significant problem noted was the porosity of phantoms generated with the thermosoftening-based printer. The aforementioned three imaging methods provided a valuable mix of insights into phantom morphology and may also be useful for detailed structural inspection of medical devices fabricated by rapid prototyping, such as customized implants. Overall, our findings indicate that 3D printing has significant potential as a method for fabricating well-characterized, standard phantoms for medical imaging modalities such as HRI.

  11. New prototype neuronavigation system based on preoperative imaging and intraoperative freehand ultrasound: system description and validation.

    PubMed

    Mercier, Laurence; Del Maestro, Rolando F; Petrecca, Kevin; Kochanowska, Anna; Drouin, Simon; Yan, Charles X B; Janke, Andrew L; Chen, Sean Jy-Shyang; Collins, D Louis

    2011-07-01

    The aim of this report is to present IBIS (Interactive Brain Imaging System) NeuroNav, a new prototype neuronavigation system that has been developed in our research laboratory over the past decade that uses tracked intraoperative ultrasound to address surgical navigation issues related to brain shift. The unique feature of the system is its ability, when needed, to improve the initial patient-to-preoperative image alignment based on the intraoperative ultrasound data. Parts of IBIS Neuronav source code are now publicly available on-line. Four aspects of the system are characterized in this paper: the ultrasound probe calibration, the temporal calibration, the patient-to-image registration and the MRI-ultrasound registration. In order to characterize its real clinical precision and accuracy, the system was tested in a series of adult brain tumor cases. Three metrics were computed to evaluate the precision and accuracy of the ultrasound calibration. 1) Reproducibility: 1.77 mm and 1.65 mm for the bottom corners of the ultrasound image, 2) point reconstruction precision 0.62-0.90 mm: and 3) point reconstruction accuracy: 0.49-0.74 mm. The temporal calibration error was estimated to be 0.82 ms. The mean fiducial registration error (FRE) of the homologous-point-based patient-to-MRI registration for our clinical data is 4.9 ± 1.1 mm. After the skin landmark-based registration, the mean misalignment between the ultrasound and MR images in the tumor region is 6.1 ± 3.4 mm. The components and functionality of a new prototype system are described and its precision and accuracy evaluated. It was found to have an accuracy similar to other comparable systems in the literature.

  12. A case series of rapid prototyping and intraoperative imaging in orbital reconstruction.

    PubMed

    Lim, Christopher G T; Campbell, Duncan I; Cook, Nicholas; Erasmus, Jason

    2015-06-01

    In Christchurch Hospital, rapid prototyping (RP) and intraoperative imaging are the standard of care in orbital trauma and has been used since February 2013. RP allows the fabrication of an anatomical model to visualize complex anatomical structures which is dimensionally accurate and cost effective. This assists diagnosis, planning, and preoperative implant adaptation for orbital reconstruction. Intraoperative imaging involves a computed tomography scan during surgery to evaluate surgical implants and restored anatomy and allows the clinician to correct errors in implant positioning that may occur during the same procedure. This article aims to demonstrate the potential clinical and cost saving benefits when both these technologies are used in orbital reconstruction which minimize the need for revision surgery.

  13. A Case Series of Rapid Prototyping and Intraoperative Imaging in Orbital Reconstruction

    PubMed Central

    Lim, Christopher G.T.; Campbell, Duncan I.; Cook, Nicholas; Erasmus, Jason

    2014-01-01

    In Christchurch Hospital, rapid prototyping (RP) and intraoperative imaging are the standard of care in orbital trauma and has been used since February 2013. RP allows the fabrication of an anatomical model to visualize complex anatomical structures which is dimensionally accurate and cost effective. This assists diagnosis, planning, and preoperative implant adaptation for orbital reconstruction. Intraoperative imaging involves a computed tomography scan during surgery to evaluate surgical implants and restored anatomy and allows the clinician to correct errors in implant positioning that may occur during the same procedure. This article aims to demonstrate the potential clinical and cost saving benefits when both these technologies are used in orbital reconstruction which minimize the need for revision surgery. PMID:26000080

  14. MuSICa at GRIS: a prototype image slicer for EST at GREGOR

    NASA Astrophysics Data System (ADS)

    Calcines, A.; Collados, M.; López, R. L.

    2013-05-01

    This communication presents a prototype image slicer for the 4-m European Solar Telescope (EST) designed for the spectrograph of the 1.5-m GREGOR solar telescope (GRIS). The design of this integral field unit has been called MuSICa (Multi-Slit Image slicer based on collimator-Camera). It is a telecentric system developed specifically for the integral field, high resolution spectrograph of EST and presents multi-slit capability, reorganizing a bidimensional field of view of 80 arcsec^{2} into 8 slits, each one of them with 200 arcsec length × 0.05 arcsec width. It minimizes the number of optical components needed to fulfil this multi-slit capability, three arrays of mirrors: slicer, collimator and camera mirror arrays (the first one flat and the other two spherical). The symmetry of the layout makes it possible to overlap the pupil images associated to each part of the sliced entrance field of view. A mask with only one circular aperture is placed at the pupil position. This symmetric characteristic offers some advantages: facilitates the manufacturing process, the alignment and reduces the costs. In addition, it is compatible with two modes of operation: spectroscopic and spectro-polarimetric, offering a great versatility. The optical quality of the system is diffraction-limited. The prototype will improve the performances of GRIS at GREGOR and is part of the feasibility study of the integral field unit for the spectrographs of EST. Although MuSICa has been designed as a solar image slicer, its concept can also be applied to night-time astronomical instruments (Collados et al. 2010, Proc. SPIE, Vol. 7733, 77330H; Collados et al. 2012, AN, 333, 901; Calcines et al. 2010, Proc. SPIE, Vol. 7735, 77351X)

  15. Prototype client/server application for biomedical text/image retrieval on the Internet

    NASA Astrophysics Data System (ADS)

    Long, L. Rodney; Berman, Lewis E.; Thoma, George R.

    1996-03-01

    At the Lister Hill National Center for Biomedical Communications, a research and development division of the National Library of Medicine (NLM), a prototype image database retrieval system has been built. This medical information retrieval system (MIRS) is a client/server application which provides Internet access to biomedical databases, including both text search/retrieval and retrieval/display of medical images associated with the text records. The MIRS graphical user interface (GUI) allows a user to formulate queries by simple, intuitive interactions with screen buttons, list boxes, and edit boxes; these interactions create structured query language (SQL) queries, which are submitted to a database manager running at NLM. The result of a MIRS query is a display showing both scrollable text records and scrollable images returned for all of the 'hits' of the query. MIRS is designed as an information-delivery vehicle intended to provide access to multiple collections of medical text and image data. The database used for initial MIRS evaluation consists of national survey data collected by the National Center for Health Statistics, including 17,000 spinal x-ray images. This survey, conducted on a sample of 27,801 persons, collected demographic, socioeconomic, and medical information, including both interview results and results acquired by direct examination by physician.

  16. Description of a prototype emission-transmission computed tomography imaging system

    NASA Technical Reports Server (NTRS)

    Lang, T. F.; Hasegawa, B. H.; Liew, S. C.; Brown, J. K.; Blankespoor, S. C.; Reilly, S. M.; Gingold, E. L.; Cann, C. E.

    1992-01-01

    We have developed a prototype imaging system that can perform simultaneous x-ray transmission CT and SPECT phantom studies. This system employs a 23-element high-purity-germanium detector array. The detector array is coupled to a collimator with septa angled toward the focal spot of an x-ray tube. During image acquisition, the x-ray fan beam and the detector array move synchronously along an arc pivoted at the x-ray source. Multiple projections are obtained by rotating the object, which is mounted at the center of rotation of the system. The detector array and electronics can count up to 10(6) cps/element with sufficient energy-resolution to discriminate between x-rays at 100-120 kVp and gamma rays from 99mTc. We have used this device to acquire x-ray CT and SPECT images of a three-dimensional Hoffman brain phantom. The emission and transmission images may be superimposed in order to localize the emission image on the transmission map.

  17. Description of a prototype emission-transmission computed tomography imaging system

    NASA Technical Reports Server (NTRS)

    Lang, T. F.; Hasegawa, B. H.; Liew, S. C.; Brown, J. K.; Blankespoor, S. C.; Reilly, S. M.; Gingold, E. L.; Cann, C. E.

    1992-01-01

    We have developed a prototype imaging system that can perform simultaneous x-ray transmission CT and SPECT phantom studies. This system employs a 23-element high-purity-germanium detector array. The detector array is coupled to a collimator with septa angled toward the focal spot of an x-ray tube. During image acquisition, the x-ray fan beam and the detector array move synchronously along an arc pivoted at the x-ray source. Multiple projections are obtained by rotating the object, which is mounted at the center of rotation of the system. The detector array and electronics can count up to 10(6) cps/element with sufficient energy-resolution to discriminate between x-rays at 100-120 kVp and gamma rays from 99mTc. We have used this device to acquire x-ray CT and SPECT images of a three-dimensional Hoffman brain phantom. The emission and transmission images may be superimposed in order to localize the emission image on the transmission map.

  18. A single-imager, single-lens video camera prototype for 3D imaging

    NASA Astrophysics Data System (ADS)

    Christopher, Lauren A.; Li, Weixu

    2012-03-01

    A new method for capturing 3D video from a single imager and lens is introduced. The benefit of this method is that it does not have the calibration and alignment issues associated with binocular 3D video cameras. It also does not require special ranging transmitters and sensors. Because it is a single lens/imager system, it is also less expensive than either the binocular or ranging cameras. Our system outputs a 2D image and associated depth image using the combination of microfluidic lens and Depth from Defocus (DfD) algorithm. The lens is capable of changing the focus to obtain two images at the normal video frame rate. The Depth from Defocus algorithm uses the in focus and out of focus images to infer depth. We performed our experiments on synthetic and on the real aperture CMOS imager with a microfluidic lens. On synthetic images, we found an improvement in mean squared error compared to the literature on a limited test set. On camera images, our research showed that DfD combined with edge detection and segmentation provided subjective improvements in the resulting depth images.

  19. Mirror-image anterior crown fabrication with computer-aided design and rapid prototyping technology: a clinical report.

    PubMed

    Cho, Seok-Hwan; Chang, Won-Gun

    2013-02-01

    This clinical report describes the fabrication of a maxillary central incisor single crown with rapid prototyping (RP) technology. A patient with a recently replaced metal ceramic crown had discomfort due to the nonanatomic lingual contour of the crown. With computer-aided design (CAD) software and rapid prototyping (RP) technology, the shape of the contralateral central incisor was duplicated and reproduced to make a mirror-image for a new crown. The prosthodontic planning and treatment approach are discussed.

  20. The STACEE Ground-Based Gamma-ray Observatory

    NASA Astrophysics Data System (ADS)

    Ragan, Ken

    2002-04-01

    The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is a ground-based instrument designed to study astrophysical sources of gamma rays in the energy range from 50 to 500 GeV using an array of heliostat mirrors at the National Solar Thermal Test Facility in New Mexico. The mirrors collect Cherenkov light generated by gamma-ray air showers and concentrate it onto cameras composed of photomultiplier tubes. The STACEE instrument is now complete, and uses a total of 64 heliostats. Prototype instruments, using smaller numbers of heliostats, have previously detected gamma emission from both the Crab Nebula and the Active Galactic Nucleus Mrk421. The complete instrument has a lower threshold -- approximately 50 GeV -- than those prototypes due to superior triggering and electronics, including flash ADCs for every channel.We will discuss the performance of the complete instrument in its first full season of operation, and present preliminary results of selected observations.

  1. Studies of a prototype linear stationary X-ray source for tomosynthesis imaging

    PubMed Central

    Schwoebel, P R; Boone, John M.; Shao, Joe

    2014-01-01

    A prototype linear X-ray source to implement stationary source – stationary detector tomosynthesis imaging has been studied. Potential applications include human breast and small animal imaging. The source is comprised of ten X-ray source elements each consisting of a field emission cathode, electrostatic lens, and target. The electrostatic lens and target are common to all elements. The source elements form X-ray focal spots with minimum diameters of 0.3 to 0.4 mm at electron beam currents of up to 40 mA with a beam voltage of 40 kV. The X-ray flux versus time was quantified from each source. X-ray bremsstrahlung spectra from tungsten targets were produced using electron beam energies from 35 to 50 keV. The half-value layer was measured to be 0.8 mm, 0.9 mm, and 1.0 mm, respectively, for the 35 kV, 40 kV, and 45 kV tube potentials using the tungsten target. The suppression of voltage breakdown events, particularly during source operation, and the use of a modified form of the standard cold-cathode geometry, enhanced source reliability. The prototype linear source was used to collect tomographic data sets of a mouse phantom using digital tomosynthesis reconstruction methods and demonstrated a slice-sensitivity profile with a full-width-half-maximum of 1.3 mm. Lastly, preliminary studies of tomographic imaging of flow through the mouse phantom were performed. PMID:24743496

  2. Studies of a prototype linear stationary x-ray source for tomosynthesis imaging.

    PubMed

    Schwoebel, P R; Boone, John M; Shao, Joe

    2014-05-21

    A prototype linear x-ray source to implement stationary source-stationary detector tomosynthesis (TS) imaging has been studied. Potential applications include human breast and small animal imaging. The source is comprised of ten x-ray source elements each consisting of a field emission cathode, electrostatic lens, and target. The electrostatic lens and target are common to all elements. The source elements form x-ray focal spots with minimum diameters of 0.3-0.4 mm at electron beam currents of up to 40 mA with a beam voltage of 40 kV. The x-ray flux versus time was quantified from each source. X-ray bremsstrahlung spectra from tungsten targets were produced using electron beam energies from 35 to 50 keV. The half-value layer was measured to be 0.8, 0.9, and 1.0 mm, respectively, for the 35, 40, and 45 kV tube potentials using the tungsten target. The suppression of voltage breakdown events, particularly during source operation, and the use of a modified form of the standard cold-cathode geometry, enhanced source reliability. The prototype linear source was used to collect tomographic data sets of a mouse phantom using digital TS reconstruction methods and demonstrated a slice-sensitivity profile with a full-width-half-maximum of 1.3 mm. Lastly, preliminary studies of tomographic imaging of flow through the mouse phantom were performed.

  3. Technical note: rapid prototyping of 3D grid arrays for image guided therapy quality assurance.

    PubMed

    Kittle, David; Holshouser, Barbara; Slater, James M; Guenther, Bob D; Pitsianis, Nikos P; Pearlstein, Robert D

    2008-12-01

    Three dimensional grid phantoms offer a number of advantages for measuring imaging related spatial inaccuracies for image guided surgery and radiotherapy. The authors examined the use of rapid prototyping technology for directly fabricating 3D grid phantoms from CAD drawings. We tested three different fabrication process materials, photopolymer jet with acrylic resin (PJ/AR), selective laser sintering with polyamide (SLS/P), and fused deposition modeling with acrylonitrile butadiene styrene (FDM/ABS). The test objects consisted of rectangular arrays of control points formed by the intersections of posts and struts (2 mm rectangular cross section) and spaced 8 mm apart in the x, y, and z directions. The PJ/AR phantom expanded after immersion in water which resulted in permanent warping of the structure. The surface of the FDM/ABS grid exhibited a regular pattern of depressions and ridges from the extrusion process. SLS/P showed the best combination of build accuracy, surface finish, and stability. Based on these findings, a grid phantom for assessing machine-dependent and frame-induced MR spatial distortions was fabricated to be used for quality assurance in stereotactic neurosurgical and radiotherapy procedures. The spatial uniformity of the SLS/P grid control point array was determined by CT imaging (0.6 x 0.6 x 0.625 mm3 resolution) and found suitable for the application, with over 97.5% of the control points located within 0.3 mm of the position specified in CAD drawing and none of the points off by more than 0.4 mm. Rapid prototyping is a flexible and cost effective alternative for development of customized grid phantoms for medical physics quality assurance.

  4. Technical Note: Rapid prototyping of 3D grid arrays for image guided therapy quality assurance

    SciTech Connect

    Kittle, David; Holshouser, Barbara; Slater, James M.; Guenther, Bob D.; Pitsianis, Nikos P.; Pearlstein, Robert D.

    2008-12-15

    Three dimensional grid phantoms offer a number of advantages for measuring imaging related spatial inaccuracies for image guided surgery and radiotherapy. The authors examined the use of rapid prototyping technology for directly fabricating 3D grid phantoms from CAD drawings. We tested three different fabrication process materials, photopolymer jet with acrylic resin (PJ/AR), selective laser sintering with polyamide (SLS/P), and fused deposition modeling with acrylonitrile butadiene styrene (FDM/ABS). The test objects consisted of rectangular arrays of control points formed by the intersections of posts and struts (2 mm rectangular cross section) and spaced 8 mm apart in the x, y, and z directions. The PJ/AR phantom expanded after immersion in water which resulted in permanent warping of the structure. The surface of the FDM/ABS grid exhibited a regular pattern of depressions and ridges from the extrusion process. SLS/P showed the best combination of build accuracy, surface finish, and stability. Based on these findings, a grid phantom for assessing machine-dependent and frame-induced MR spatial distortions was fabricated to be used for quality assurance in stereotactic neurosurgical and radiotherapy procedures. The spatial uniformity of the SLS/P grid control point array was determined by CT imaging (0.6x0.6x0.625 mm{sup 3} resolution) and found suitable for the application, with over 97.5% of the control points located within 0.3 mm of the position specified in CAD drawing and none of the points off by more than 0.4 mm. Rapid prototyping is a flexible and cost effective alternative for development of customized grid phantoms for medical physics quality assurance.

  5. Monitoring the Sky with the Prototype All-Sky Imager on the LWA1

    NASA Astrophysics Data System (ADS)

    Obenberger, K. S.; Taylor, G. B.; Hartman, J. M.; Clarke, T. E.; Dowell, J.; Dubois, A.; Dubois, D.; Henning, P. A.; Lazio, J.; Michalak, S.; Schinzel, F. K.

    2015-03-01

    We present a description of the Prototype All-Sky Imager (PASI), a backend correlator and imager of the first station of the Long Wavelength Array (LWA1). PASI cross-correlates a live stream of 260 dual-polarization dipole antennas of the LWA1, creates all-sky images, and uploads them to the LWA-TV website in near real time. PASI has recorded over 13,000hr of all-sky images at frequencies between 10 and 88MHz creating opportunities for new research and discoveries. We also report rate density and pulse energy density limits on transients at 38, 52, and 74MHz, for pulse widths of 5s. We limit transients at those frequencies with pulse energy densities of >2.7×10-23, >1.1×10-23, and >2.8×10-23Jm-2Hz-1 to have rate densities <1.2×10-4, <5.6×10-4, and <7.2×10-4 year-1deg-2.

  6. Rapid Prototyping of Hyperspectral Image Analysis Algorithms for Improved Invasive Species Decision Support Tools

    NASA Astrophysics Data System (ADS)

    Bruce, L. M.; Ball, J. E.; Evangilista, P.; Stohlgren, T. J.

    2006-12-01

    Nonnative invasive species adversely impact ecosystems, causing loss of native plant diversity, species extinction, and impairment of wildlife habitats. As a result, over the past decade federal and state agencies and nongovernmental organizations have begun to work more closely together to address the management of invasive species. In 2005, approximately 500M dollars was budgeted by U.S. Federal Agencies for the management of invasive species. Despite extensive expenditures, most of the methods used to detect and quantify the distribution of these invaders are ad hoc, at best. Likewise, decisions on the type of management techniques to be used or evaluation of the success of these methods are typically non-systematic. More efficient methods to detect or predict the occurrence of these species, as well as the incorporation of this knowledge into decision support systems, are greatly needed. In this project, rapid prototyping capabilities (RPC) are utilized for an invasive species application. More precisely, our recently developed analysis techniques for hyperspectral imagery are being prototyped for inclusion in the national Invasive Species Forecasting System (ISFS). The current ecological forecasting tools in ISFS will be compared to our hyperspectral-based invasives prediction algorithms to determine if/how the newer algorithms enhance the performance of ISFS. The PIs have researched the use of remotely sensed multispectral and hyperspectral reflectance data for the detection of invasive vegetative species. As a result, the PI has designed, implemented, and benchmarked various target detection systems that utilize remotely sensed data. These systems have been designed to make decisions based on a variety of remotely sensed data, including high spectral/spatial resolution hyperspectral signatures (1000's of spectral bands, such as those measured using ASD handheld devices), moderate spectral/spatial resolution hyperspectral images (100's of spectral bands, such

  7. 3D imaging acquisition, modeling, and prototyping for facial defects reconstruction

    NASA Astrophysics Data System (ADS)

    Sansoni, Giovanna; Trebeschi, Marco; Cavagnini, Gianluca; Gastaldi, Giorgio

    2009-01-01

    A novel approach that combines optical three-dimensional imaging, reverse engineering (RE) and rapid prototyping (RP) for mold production in the prosthetic reconstruction of facial prostheses is presented. A commercial laser-stripe digitizer is used to perform the multiview acquisition of the patient's face; the point clouds are aligned and merged in order to obtain a polygonal model, which is then edited to sculpture the virtual prothesis. Two physical models of both the deformed face and the 'repaired' face are obtained: they differ only in the defect zone. Depending on the material used for the actual prosthesis, the two prototypes can be used either to directly cast the final prosthesis or to fabricate the positive wax pattern. Two case studies are presented, referring to prostetic reconstructions of an eye and of a nose. The results demonstrate the advantages over conventional techniques as well as the improvements with respect to known automated manufacturing techniques in the mold construction. The proposed method results into decreased patient's disconfort, reduced dependence on the anaplasthologist skill, increased repeatability and efficiency of the whole process.

  8. Quantitative myocardial perfusion imaging in a porcine ischemia model using a prototype spectral detector CT system.

    PubMed

    Fahmi, Rachid; Eck, Brendan L; Levi, Jacob; Fares, Anas; Dhanantwari, Amar; Vembar, Mani; Bezerra, Hiram G; Wilson, David L

    2016-03-21

    We optimized and evaluated dynamic myocardial CT perfusion (CTP) imaging on a prototype spectral detector CT (SDCT) scanner. Simultaneous acquisition of energy sensitive projections on the SDCT system enabled projection-based material decomposition, which typically performs better than image-based decomposition required by some other system designs. In addition to virtual monoenergetic, or keV images, the SDCT provided conventional (kVp) images, allowing us to compare and contrast results. Physical phantom measurements demonstrated linearity of keV images, a requirement for quantitative perfusion. Comparisons of kVp to keV images demonstrated very significant reductions in tell-tale beam hardening (BH) artifacts in both phantom and pig images. In phantom images, consideration of iodine contrast to noise ratio and small residual BH artifacts suggested optimum processing at 70 keV. The processing pipeline for dynamic CTP measurements included 4D image registration, spatio-temporal noise filtering, and model-independent singular value decomposition deconvolution, automatically regularized using the L-curve criterion. In normal pig CTP, 70 keV perfusion estimates were homogeneous throughout the myocardium. At 120 kVp, flow was reduced by more than 20% on the BH-hypo-enhanced myocardium, a range that might falsely indicate actionable ischemia, considering the 0.8 threshold for actionable FFR. With partial occlusion of the left anterior descending (LAD) artery (FFR < 0.8), perfusion defects at 70 keV were correctly identified in the LAD territory. At 120 kVp, BH affected the size and flow in the ischemic area; e.g. with FFR ≈ 0.65, the anterior-to-lateral flow ratio was 0.29 ± 0.01, over-estimating stenosis severity as compared to 0.42 ± 0.01 (p < 0.05) at 70 keV. On the non-ischemic inferior wall (not a LAD territory), the flow ratio was 0.50 ± 0.04 falsely indicating an actionable ischemic condition in a healthy territory. This ratio was 1.00 ± 0.08 at 70 ke

  9. Quantitative myocardial perfusion imaging in a porcine ischemia model using a prototype spectral detector CT system

    NASA Astrophysics Data System (ADS)

    Fahmi, Rachid; Eck, Brendan L.; Levi, Jacob; Fares, Anas; Dhanantwari, Amar; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    We optimized and evaluated dynamic myocardial CT perfusion (CTP) imaging on a prototype spectral detector CT (SDCT) scanner. Simultaneous acquisition of energy sensitive projections on the SDCT system enabled projection-based material decomposition, which typically performs better than image-based decomposition required by some other system designs. In addition to virtual monoenergetic, or keV images, the SDCT provided conventional (kVp) images, allowing us to compare and contrast results. Physical phantom measurements demonstrated linearity of keV images, a requirement for quantitative perfusion. Comparisons of kVp to keV images demonstrated very significant reductions in tell-tale beam hardening (BH) artifacts in both phantom and pig images. In phantom images, consideration of iodine contrast to noise ratio and small residual BH artifacts suggested optimum processing at 70 keV. The processing pipeline for dynamic CTP measurements included 4D image registration, spatio-temporal noise filtering, and model-independent singular value decomposition deconvolution, automatically regularized using the L-curve criterion. In normal pig CTP, 70 keV perfusion estimates were homogeneous throughout the myocardium. At 120 kVp, flow was reduced by more than 20% on the BH-hypo-enhanced myocardium, a range that might falsely indicate actionable ischemia, considering the 0.8 threshold for actionable FFR. With partial occlusion of the left anterior descending (LAD) artery (FFR  <  0.8), perfusion defects at 70 keV were correctly identified in the LAD territory. At 120 kVp, BH affected the size and flow in the ischemic area; e.g. with FFR ≈ 0.65, the anterior-to-lateral flow ratio was 0.29  ±  0.01, over-estimating stenosis severity as compared to 0.42  ±  0.01 (p  <  0.05) at 70 keV. On the non-ischemic inferior wall (not a LAD territory), the flow ratio was 0.50  ±  0.04 falsely indicating an actionable ischemic condition in a healthy

  10. Challenges and Rewards in Ground-Based Observing

    NASA Astrophysics Data System (ADS)

    Reardon, Kevin P.

    2016-05-01

    DKIST will be largest ground-based project in solar physics, and will offer access and data to the whole community. In pursuit of exciting science, many users may have their first encounters with high-resolution, ground-based solar observations. New facilities, space or ground-based, all bring particular signatures in their data. While tools or processed datasets might serve to minimize such non-solar signatures, it is nonetheless important for users to understand the impacts on observation planning, the nature of the corrections applied, and any residual effects on their data.In this talk I will review some of the instrumental and atmospheric signatures that are important for ground-based observing, in particular in planning for the potential capabilities of the DKIST Data Center. These techniques include image warping, local PSF deconvolution, atmospheric dispersion correction, and scattered light removal. I will present examples of data sets afflicted by such problems as well as some of the algorithms used in characterizing and removing these contributions. This will demonstrate how even with the challenges of observing through a turbulent atmosphere, it is possible to achieve dramatic scientific results.

  11. Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) for WFIRST/AFTA

    NASA Technical Reports Server (NTRS)

    Gong, Qian; Mcelwain, Michael; Greeley, Bradford; Grammer, Bryan; Marx, Catherine; Memarsadeghi, Nargess; Stapelfeldt, Karl; Hilton, George; Sayson, Jorge Llop; Perrin, Marshall; hide

    2015-01-01

    Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) is a lenslet array based integral field spectrometer (IFS) designed for high contrast imaging of extrasolar planets. PISCES will be used to advance the technology readiness of the high contrast IFS baselined on the Wide-Field InfraRed Survey Telescope/Astrophysics Focused Telescope Assets (WFIRST/AFTA) coronagraph instrument. PISCES will be integrated into the high contrast imaging testbed (HCIT) at the Jet Propulsion Laboratory and will work with both the Hybrid Lyot Coronagraph (HLC) and the Shaped Pupil Coronagraph (SPC) cofigurations. We discuss why the lenslet array based IFS is selected for PISCES. We present the PISCES optical design, including the similarities and differences of lenslet based IFSs to normal spectrometers, the trade-off between a refractive design and reflective design, as well as the specific function of our pinhole mask on the back surface of the lenslet array to further suppress star light introduced speckles. The optical analysis, alignment plan, and mechanical design of the instrument will be discussed.

  12. Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) for WFIRST-AFTA

    NASA Technical Reports Server (NTRS)

    Gong, Qian; Mcelwain, Michael; Greeley, Bradford; Grammer, Bryan; Marx, Catherine; Memarsadeghi, Nargess; Stapelfeldt, Karl; Hilton, George; Sayson, Jorge Llop; Perrin, Marshall; hide

    2015-01-01

    Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) is a lenslet array based integral field spectrometer (IFS) designed for high contrast imaging of extrasolar planets. PISCES will be used to advance the technology readiness of the high contrast IFS baselined on the Wide-Field InfraRed Survey Telescope/Astrophysics Focused Telescope Assets (WFIRST-AFTA) coronagraph instrument. PISCES will be integrated into the high contrast imaging testbed (HCIT) at the Jet Propulsion Laboratory (JPL) and will work with both the Hybrid Lyot Coronagraph (HLC) and the Shaped Pupil Coronagraph (SPC) configurations. We discuss why the lenslet array based IFS was selected for PISCES. We present the PISCES optical design, including the similarities and differences of lenslet based IFSs to normal spectrometers, the trade-off between a refractive design and reflective design, as well as the specific function of our pinhole mask on the back surface of the lenslet array to reduce the diffraction from the edge of the lenslets. The optical analysis, alignment plan, and mechanical design of the instrument will be discussed.

  13. MuSICa image slicer prototype at 1.5-m GREGOR solar telescope

    NASA Astrophysics Data System (ADS)

    Calcines, A.; López, R. L.; Collados, M.; Vega Reyes, N.

    2014-07-01

    Integral Field Spectroscopy is an innovative technique that is being implemented in the state-of-the-art instruments of the largest night-time telescopes, however, it is still a novelty for solar instrumentation. A new concept of image slicer, called MuSICa (Multi-Slit Image slicer based on collimator-Camera), has been designed for the integral field spectrograph of the 4-m European Solar Telescope. This communication presents an image slicer prototype of MuSICa for GRIS, the spectrograph of the 1.5-m GREGOR solar telescope located at the Observatory of El Teide. MuSICa at GRIS reorganizes a 2-D field of view of 24.5 arcsec into a slit of 0.367 arcsec width by 66.76 arcsec length distributed horizontally. It will operate together with the TIP-II polarimeter to offer high resolution integral field spectropolarimetry. It will also have a bidimensional field of view scanning system to cover a field of view up to 1 by 1 arcmin.

  14. Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) for WFIRST-AFTA

    NASA Technical Reports Server (NTRS)

    Gong, Qian; Mcelwain, Michael; Greeley, Bradford; Grammer, Bryan; Marx, Catherine; Memarsadeghi, Nargess; Stapelfeldt, Karl; Hilton, George; Sayson, Jorge Llop; Perrin, Marshall; Demers, Richard; Tang, Hong; Kern, Brian; Ferdosi, Janan

    2015-01-01

    Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) is a lenslet array based integral field spectrometer (IFS) designed for high contrast imaging of extrasolar planets. PISCES will be used to advance the technology readiness of the high contrast IFS baselined on the Wide-Field InfraRed Survey Telescope/Astrophysics Focused Telescope Assets (WFIRST-AFTA) coronagraph instrument. PISCES will be integrated into the high contrast imaging testbed (HCIT) at the Jet Propulsion Laboratory (JPL) and will work with both the Hybrid Lyot Coronagraph (HLC) and the Shaped Pupil Coronagraph (SPC) configurations. We discuss why the lenslet array based IFS was selected for PISCES. We present the PISCES optical design, including the similarities and differences of lenslet based IFSs to normal spectrometers, the trade-off between a refractive design and reflective design, as well as the specific function of our pinhole mask on the back surface of the lenslet array to reduce the diffraction from the edge of the lenslets. The optical analysis, alignment plan, and mechanical design of the instrument will be discussed.

  15. Monitoring the Low Frequency Sky with the LWA1 and the Prototype All-Sky Imager

    NASA Astrophysics Data System (ADS)

    Obenberger, Kenneth Steven; LWA Collaboration

    2015-01-01

    We present findings from the Prototype All-Sky Imager (PASI), a backend correlator of the first station of the Long Wavelength Array (LWA1). PASI cross-correlates a live stream of all 260 dual-polarization dipole antennas of the LWA1, creates all-sky images, and uploads them to the LWA-TV website in near real-time. PASI has recorded over 14,000 hours of all-sky images at frequencies between 10 and 88 MHz. These data have resulted in the discovery of radio emission from large meteors (Fireballs), and has been used to set improved limits on slow transients at 38, 52, and 74 MHz. PASI is also being used to characterize how the ionosphere affects low frequency transient astronomy. Construction of the LWA has been supported by the Office of Naval Research under Contract N00014-07-C-0147. Support for operations and continuing development of the LWA1 is provided by the National Science Foundation under grants AST-1139963 and AST-1139974 of the University Radio Observatory program.

  16. Network image data bank prototype: the RSI project (Resume de Sortie Images)

    NASA Astrophysics Data System (ADS)

    Abouchi, Nacer; Jourlin, Michel; Bohbot, Oriana; Faurie, Catherine; Grisel, Richard

    1995-02-01

    The Hospital Edouard Herriot in Lyon and 3M company, associated with the Electronic Department of Physics Chimics and Electronic Engineering School (CPE), decided in 1993 to begin a study on a project of image network. This project is composed of many practical applications to be checked one by one. The purpose of this paper is to discuss the context, which is kind of small picture archiving and communication system (PACS), to explain the methodology which has been used related to hardware and software implementation, and to give examples of the first results obtained. One of the main interests of the results is the possibility to obtain on the same support, 3M laser imager, a film including images from different modalities and abstract summing up the patient stay in the hospital. The framework used is built around Omnis7 and C++ language on a PC computer.

  17. Field flatteners fabricated with a rapid prototyper for K-edge subtraction imaging of small animals

    NASA Astrophysics Data System (ADS)

    Zhu, Ying; Zhang, Honglin; Bewer, Brian; Florin Gh. Popescu, Bogdan; Nichol, Helen; Chapman, Dean

    2008-04-01

    One of the difficulties in X-ray imaging is the need to record a wide dynamic range of intensities on the detector. For example, some rays may miss the object being imaged entirely while others may suffer many orders of magnitude attenuation in passing through. In K-edge subtraction (KES) [E. Rubenstein, et al., Trans. Am. Clin. Climatol. Assoc. 97 (1985) 27.] imaging subtle differences in transmission through an object about the absorption edge of an element are used to create an image of the projected density of that element. This is done by a logarithmic subtraction of images acquired with energies above and below the absorption edge. For KES, the detector must register this transmitted intensity range in a linear manner for the subtraction method to be successful. The range of intensities which may strike the detector has inspired the concept of a field flattener. A field flattener is a device placed in the beam path that attenuates the input monochromatic beam to equalize X-ray absorption due to differences in the density of soft and hard tissues of an object before it passes through the object and thus achieves a flattened image. This removes the need for a wide dynamic range linear detector and allows detectors with modest performance to be used successfully in KES applications. The field flattener improves the S/ N ratio since X-ray exposures can be increased up to detector saturation. However, a field flattener removes anatomical information from each raw image (above or below K-edge) that may provide useful landmarks. Using rapid prototyping technology, two sets of field flatteners were fabricated and used in a KES experiment. This paper describes the procedure to design and fabricate field flatteners based on animal images from X-ray computed tomography (CT). Analysis of experimental data and KES images of a rat head with and without the field flattener are also presented. The results show a promising improvement of S/ N ratio using a field flattener

  18. Unbiased Review of Digital Diagnostic Images in Practice: Informatics Prototype and Pilot Study

    PubMed Central

    Fotenos, Anthony F.; Safdar, Nabile M.; Nagy, Paul G.; Mezrich, Reuben; Lewin, Jonathan S.

    2013-01-01

    Rationale and Objectives Clinical and contextual information associated with images may influence how radiologists draw diagnostic inferences, highlighting the need to control multiple sources of bias in the methodological design of investigations involving radiological interpretation. In the past, manual control methods to mask review films presented in practice have been used to reduce potential interpretive bias associated with differences between viewing images for patient care versus reviewing images for purposes of research, education, and quality improvement. These manual precedents from the film era raise the question whether similar methods to reduce bias can be implemented in the modern digital environment. Materials and Methods We built prototype “CreateAPatient” information technology for masking review case presentations within our institution’s production Radiology Information and Picture Archiving and Reporting Systems (RIS and PACS). To test whether CreateAPatient could be used to mask review images presented in practice, six board-certified radiologists participated in a pilot study. During pilot testing, seven digital chest radiographs, known to contain lung nodules and associated with fictitious patient identifiers, were mixed into the routine workload of the participating radiologists while they covered general evening call shifts. We tested whether it was possible to mask the presentation of these review cases, both by probing the interpreting radiologists to report detection and by conducting a forced-choice experiment on a separate cohort of 20 radiologists and information technology professionals. Results None of the participating radiologists reported awareness of review activity, and forced-choice detection was less than predicted at chance, suggesting radiologists were effectively blinded. In addition, we identified no evidence of review reports unsafely propagating beyond their intended scope or otherwise interfering with patient

  19. Introduction: Photons and Ground-Based

    NASA Technical Reports Server (NTRS)

    Spann, James; Moore, Thomas

    2017-01-01

    A Conference on Measurement Techniques for Solar and Space Physics was held on 20-24 April 2015 in Boulder, Colorado, at the National Center for Atmospheric Research Center Green Campus. The present volume collects together the conference papers for photons and ground-based categories. This gathering of over 200 scientists and instrumentalists was born out of the desire to collect in one place the latest experiment and instrument technologies required for advancement of scientific knowledge in the disciplines of solar and space physics. The two goals for this conference and the subsequent publication of its content are (a) to describe measurement techniques and technology development needed to advance high priority science in the fields of solar and space physics; and (b) to provide a survey or reference of techniques for in situ measurement and remote sensing of space plasmas. Towards this end, our goal has always been inspired by the two 1998 Geophysical Monographs (Nos. 102 and 103) entitled, "Measurement Techniques in Space Plasmas" (particles and fields) [Pfaff et al., 1998a, 1998b], which have served as a reference and resource for advanced students, engineers, and scientists who wish to learn the fundamentals of measurement techniques and technology in this field. Those monographs were the product of an American Geophysical Union Chapman Conference that took place in Santa Fe, NM, in 1995: "Measurement Techniques in Space Plasmas-What Works, What Doesn't." Two decades later, we believe that it is appropriate to revisit this subject, in light of recent advances in technology, research platforms, and analysis techniques. Moreover, we now include direct measurements of neutral gases in the upper atmosphere, optical imaging techniques, and remote observations in space and on the ground. Accordingly, the workshop was organized among four areas of measurement techniques: particles, fields, photons, and ground-based. This two-set volume is largely composed of the

  20. A prototype small CdTe gamma camera for radioguided surgery and other imaging applications.

    PubMed

    Tsuchimochi, Makoto; Sakahara, Harumi; Hayama, Kazuhide; Funaki, Minoru; Ohno, Ryoichi; Shirahata, Takashi; Orskaug, Terje; Maehlum, Gunnar; Yoshioka, Koki; Nygard, Einar

    2003-12-01

    Gamma probes have been used for sentinel lymph node biopsy in melanoma and breast cancer. However, these probes can provide only radioactivity counts and variable pitch audio output based on the intensity of the detected radioactivity. We have developed a small semiconductor gamma camera (SSGC) that allows visualisation of the size, shape and location of the target tissues. This study is designed to characterise the performance of the SSGC for radioguided surgery of metastatic lesions and for other imaging applications amenable to the smaller format of this prototype imaging system. The detector head had 32 cadmium telluride semiconductor arrays with a total of 1,024 pixels, and with application-specific integrated circuits (ASICs) and a tungsten collimator. The entire assembly was encased in a lead housing measuring 152 mmx166 mmx65 mm. The effective visual field was 44.8 mmx44.8 mm. The energy resolution and imaging aspects were tested. Two spherical 5-mm- and 15-mm-diameter technetium-99m radioactive sources that had activities of 0.15 MBq and 100 MBq, respectively, were used to simulate a sentinel lymph node and an injection site. The relative detectability of these foci by the new detector and a conventional scintillation camera was studied. The prototype was also examined in a variety of clinical applications. Energy resolution [full-width at half-maximum (FWHM)] for a single element at the centre of the field of view was 4.2% at 140 keV (99mTc), and the mean energy resolution of the CdTe detector arrays was approximately 7.8%. The spatial resolution, represented by FWHM, had a mean value of 1.56 +/- 0.05 mm. Simulated node foci could be visualised clearly by the SSGC using a 15-s acquisition time. In preliminary clinical tests, the SSGC successfully imaged diseases in a variety of tissues, including salivary and thyroid glands, temporomandibular joints and sentinel lymph nodes. The SSGC has significant potential for diagnosing diseases and facilitating

  1. Multichannel optical aperture synthesis imaging of zeta1 URSAE majoris with the Navy prototype optical interferometer.

    NASA Astrophysics Data System (ADS)

    Benson, J. A.; Hutter, D. J.; Elias, N. M., II; Bowers, P. F.; Johnston, K. J.; Hajian, A. R.; Armstrong, J. T.; Mozurkewich, D.; Pauls, T. A.; Rickard, L. J.; Hummel, C. A.; White, N. M.; Black, D.; Denison, C. S.

    1997-09-01

    We have used the Navy Prototype Optical Interferometer (NPOI) to obtain the first multi-channel optical aperture synthesis images of a star. We observed the spectroscopic binary zeta (1) Ursae Majoris at 6 to 10 milliarcseconds separation during seven nights, using three interferometric baselines and 19 spectral channels (lambda lambda520 - 850 nm) of the NPOI. After editing, a typical 90 sec scan yielded fringe visibilities at 50 spatial frequencies and closure phases at 15 wavelengths. Three to five scans were obtained each night. The separations and position angles are in good agreement with the visual orbit obtained with the Mark III interferometer (Hummel et al.markcite{hum1} 1995 [AJ, 110, 376]) but show small systematic difference that can be used to improve the orbit. The closure phase data provide a sensitive measure of the magnitude difference between the components. These results demonstrate the power of broad-band interferometric observations for fast imaging and the utility of vacuum delay lines for simultaneous observations over a wide band. These observations are the first to produce simultaneous visibilities and closure phases with a separate-aperture optical interferometer, and the second to produce closure phase images, following the results from COAST reported by Baldwin et al.markcite{bal} (1996 [A&A, 306, L13]). The angular resolution here is the highest ever achieved at visual wavelengths, exceeding by an order of magnitude the best thus far achieved by any single-aperture optical telescope. We generated complex visibilities and closure phases (the data types commonly used in radio interferometry) from the optical data and used standard radio interferometry techniques to produce these images. However, the fundamental observables of optical interferometry, the squared visibility amplitude and the closure phase, require the development of new analysis techniques.

  2. A high resolution prototype small-animal PET scanner dedicated to mouse brain imaging

    PubMed Central

    Yang, Yongfeng; Bec, Julien; Zhou, Jian; Zhang, Mengxi; Judenhofer, Martin S; Bai, Xiaowei; Di, Kun; Wu, Yibao; Rodriguez, Mercedes; Dokhale, Purushottam; Shah, Kanai S.; Farrell, Richard; Qi, Jinyi; Cherry, Simon R.

    2017-01-01

    A prototype small-animal PET scanner was developed based on depth-encoding detectors using dual-ended readout of very small scintillator elements to produce high and uniform spatial resolution suitable for imaging the mouse brain. Methods The scanner consists of 16 tapered dual-ended readout detectors arranged in a ring of diameter 61 mm. The axial field of view is 7 mm and the transaxial field of view is 30 mm. The scintillator arrays consist of 14×14 lutetium oxyorthosilicate (LSO) elements, with a crystal size of 0.43×0.43 mm2 at the front end and 0.80×0.43 mm2 at the back end, and the crystal elements are 13 mm long. The arrays are read out by 8×8 mm2 and a 13×8 mm2 position-sensitive avalanche photodiodes (PSAPDs) placed at opposite ends of the array. Standard nuclear instrumentation module (NIM) electronics and a custom designed multiplexer are used for signal processing. Results The detector performance was measured and all except the very edge crystals could be clearly resolved. The average detector intrinsic spatial resolution in the axial direction was 0.61 mm. A depth of interaction resolution of 1.7 mm was achieved. The sensitivity of the scanner at center of the field of view was 1.02% for a lower energy threshold of 150 keV and 0.68% for a lower energy threshold of 250 keV. The spatial resolution within a field of view that can accommodate the entire mouse brain was ~0.6 mm using a 3D Maximum Likelihood-Expectation Maximization (ML-EM) reconstruction algorithm. Images of a micro hot-rod phantom showed that rods with diameter down to 0.5 mm could be resolved. First in vivo studies were obtained using 18F-fluoride and confirmed that 0.6 mm resolution can be achieved in the mouse head in vivo. Brain imaging studies with 18F-fluorodeoxyglucose were also acquired. Conclusion A prototype PET scanner achieving a spatial resolution approaching the physical limits for a small-bore PET scanner set by positron range and acolinearity was developed. Future

  3. Performance confirmation of the Belle II imaging Time Of Propogation (iTOP) prototype counter

    SciTech Connect

    Schwartz, Alan; Liu, Yang; Belhorn, Matt; Browder, Thomas; Varner, Gary; Andrew, Matt; Rosen, Marc; Barrett, Matthew; Nishimura, Kurtis; Anderson, Eric Iijima, Toru; /Nagoya U. /PNL, Richland

    2011-10-17

    modest image expansion volume and more highly pixelated image plane improve the theoretical detector performance, since timing alone is limited by chromatic dispersion of the Cherenkov photons. This imaging-TOP (or iTOP) counter is the basis of Belle II barrel PID upgrade. However, a number of critical performance parameters must be demonstrated prior to releasing this prototype design for production manufacture.

  4. Development of a prototype infrared imaging bolometer for NSTX-U

    NASA Astrophysics Data System (ADS)

    van Eden, G. G.; Delgado-Aparicio, L. F.; Gray, T. K.; Jaworski, M. A.; Morgan, T. W.; Peterson, B. J.; Reinke, M. L.; Sano, R.; Mukai, K.; Differ/Pppl Collaboration; Nifs/Pppl Collaboration

    2015-11-01

    Measurements of the radiated power in fusion reactors are of high importance for studying detachment and the overall power balance. A prototype Infrared Video Bolometer (IRVB) is being developed for NSTX-U complementing resistive bolometer and AXUV diode diagnostics. The IRVB has proven to be a powerful tool on LHD and JT-60U for its 2D imaging quality and reactor environment compatibility. For NSTX-U, a poloidal view of the lower center stack and lower divertor are envisaged for the 2016 run campaign. The IRVB concept images radiation from the plasma onto a 2.5 μm thick 9 x 7 cm2 calibrated Pt foil and monitors its temperature evolution using an IR camera (SB focal plane, 2-12 μm, 128x128 pixels, 1.6 kHz). The power incident on the foil is calculated by solving the 2D +time heat diffusion equation. Benchtop characterization is presented, demonstrating a sensitivity of approximately 20 mK and a noise equivalent power density of 71.5 μW cm-2 for 4x20 bolometer super-pixels and a 50 Hz time response. The hardware design, optimization of camera and detector settings as well as first results of both synthetic and experimental origin are discussed.

  5. The High Energy Telescope on EXIST: The First Prototype of Advanced Imaging CZT Detectors

    NASA Astrophysics Data System (ADS)

    Hong, JaeSub; Allen, B.; Grindlay, J.; Barthelmy, S.; Gehrels, N.; Skinner, G.; Finger, M.; Jernigan, G.; EXIST Team

    2009-12-01

    The High Energy Telescope (HET) on EXIST is a coded-aperture telescope using a large array of CZT detectors and hybrid tungsten mask. The HET will locate high red-shift Gamma-Ray Bursts (GRBs) and other rare elusive transients quickly (<10 sec) and accurately (<20") for rapid (<1-2 min) follow-up onboard optical/IR imaging and spectroscopy. The HET will also survey the highly variable transient hard X-ray sky on unprecedented time scales, scanning nearly the entire sky in every two orbits (3 hour). A key challenge of the HET is to develop a large array (4.5m2) of fine pixel imaging CZT detectors. We report the recent progress in the first prototype CZT detector module (16x16 cm2). We plan to test two of such modules in a near space environment through our balloon experiment - ProtoEXIST1. The first flight is scheduled in Fall 2009. ProtoEXIST1 is the first in a series of increasingly sophisticated detector development programs to fulfill the technology requirement for the HET on EXIST.

  6. The VO and Ground-Based Data

    NASA Astrophysics Data System (ADS)

    Huchra, John

    The era of extremely large public databases in astronomy is upon us. such databases are opening the field to new research and new researchers. However it is important to be sure the resources are available to properly archive ground-based astronomical data and include the necessary quality checks and calibrations. A Virtual Observatory without proper archives will have limited usefulness. This also implies that with limited resources not all data can or should be archived. NASA already has a very good handle on US space-based astronomical data. Agencies and organizations that operate astronomical facilities particularly ground based observatories need to plan and budget for these activities now. We should not underestimate the effort required to produce high quality data products that will be useful for the broader community. Currently the best way to ""fill"" archives is with data ftom surveys. That will continue to be the case for most ground based observatories.

  7. High Resolution Energetic X-ray Imager (HREXI) for a Prototype 12U CubeSat

    NASA Astrophysics Data System (ADS)

    Hong, JaeSub; Allen, Branden; Grindlay, Jonathan E.; Barthelmy, Scott Douglas; Harrison, Fiona

    2017-08-01

    Our High Resolution Energetic X-ray Imager (HREXI) program is developing an Engineering Model (EM) for a 12U CubeSat wide-field hard X-ray (3-200 keV) coded-aperture imaging telescope. HREXI employs an array of CdZnTe (CZT) detectors (each 2 x 2 x 0.3 cm) with a fine-pixellated Tungsten coded aperture mask. The detector assembly utilizes the new technology of Through-Silicon-Vias (TSVs) to control and readout signals from the ASIC bonded to each CZT. TSVs eliminate the need for conventional wire-bonds for electric connections between the ASIC and back end electronics, greatly lowering the assembly complexity and cost, and thus enabling close-tiling of HREXI detectors in a small form factor with comfortable margins. For HREXI EM, we have successfully implemented TSVs on NuSTAR ASICs, which can cover an energy range of 3-200 keV with a FWHM spectral resolution of 1-2 keV. The 12U CubeSat HREXI EM prototype with 64 CZT detectors would image 0.5 sr of sky with FWHM field of view with 11 arcmin resolution for the current generation of the TSV-ASIC and a 20 cm mask - detector plane separation. A flight test of this 12U-HREXI will be proposed after full development and environmental testing to enable a future proposed array of SmallSat-HREXI telescopes with ~2 arcmin resolution for simultaneous full-sky studies of high redshift GRBs and a wide range of transients in the post-Swift era. (This work is supported by NASA grant NNX17AE62G)

  8. Ground-based gravitational-wave observatories

    NASA Astrophysics Data System (ADS)

    Giaime, Joseph

    2017-01-01

    After decades of development and recent upgrades, a network of ground-based interferometric gravitational-wave detectors has begun regular operation. Last year LIGO's two detectors ran for ca. 4 months, observing waves emitted during the inspiral and coalescence of pairs of black holes hundreds of megaparsec from Earth. The results from LIGO's first observational run will be described, as will plans and expectations for a larger network to include Virgo in Europe and other ground-based detectors in the coming years.

  9. Image quality of a prototype direct conversion detector for digital mammography

    NASA Astrophysics Data System (ADS)

    Mainprize, James G.; Ford, Nancy L.; Yin, Shi; Tumer, Tumay O.; Yaffe, Martin J.

    1999-05-01

    prototype to use a photoconductor with higher density and atomic number to improve quantum interaction efficiency and reduce geometric constraints on image quality.

  10. A study of artefacts in simultaneous PET and MR imaging using a prototype MR compatible PET scanner.

    PubMed

    Slates, R B; Farahani, K; Shao, Y; Marsden, P K; Taylor, J; Summers, P E; Williams, S; Beech, J; Cherry, S R

    1999-08-01

    We have assessed the possibility of artefacts that can arise in attempting to perform simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) using a small prototype MR compatible PET scanner (McPET). In these experiments, we examine MR images for any major artefacts or loss in image quality due to inhomogeneities in the magnetic field, radiofrequency interference or susceptibility effects caused by operation of the PET system inside the MR scanner. In addition, possible artefacts in the PET images caused by the static and time-varying magnetic fields or radiofrequency interference from the MR system were investigated. Biological tissue and a T2-weighted spin echo sequence were used to examine susceptibility artefacts due to components of the McPET scanner (scintillator, optical fibres) situated in the MR field of view. A range of commonly used MR pulse sequences was studied while acquiring PET data to look for possible artefacts in either the PET or MR images. Other than a small loss in signal-to-noise using gradient echo sequences, there was no significant interaction between the two imaging systems. Simultaneous PET and MR imaging of simple phantoms was also carried out in different MR systems with field strengths ranging from 0.2 to 4.7 T. The results of these studies demonstrate that it is possible to acquire PET and MR images simultaneously, without any significant artefacts or loss in image quality, using our prototype MR compatible PET scanner.

  11. First coincidences in pre-clinical Compton camera prototype for medical imaging

    NASA Astrophysics Data System (ADS)

    Studen, A.; Burdette, D.; Chesi, E.; Cindro, V.; Clinthorne, N. H.; Dulinski, W.; Fuster, J.; Han, L.; Kagan, H.; Lacasta, C.; Llosá, G.; Marques, A. C.; Malakhov, N.; Meier, D.; Mikuž, M.; Park, S. J.; Roe, S.; Rogers, W. L.; Steinberg, J.; Weilhammer, P.; Wilderman, S. J.; Zhang, L.; Žontar, D.

    2004-09-01

    Compton collimated imaging may improve the detection of gamma rays emitted by radioisotopes used in single photon emission computed tomography (SPECT). We present a crude prototype consisting of a single 500μm thick, 256 pad silicon detector with pad size of 1.4×1.4mm2, combined with a 15×15×1cm3 NaI scintillator crystal coupled to a set of 20 photo multipliers. Emphasis is placed on the performance of the silicon detector and the associated read-out electronics, which has so far proved to be the most challenging part of the set-up. Results were obtained using the VATAGP3, 128 channel low-noise self-triggering ASIC as the silicon detector's front-end. The noise distribution (σ) of the spectroscopic outputs gave an equivalent noise charge (ENC) with a mean value of <σ>=137e with a spread of 10e, corresponding to an energy resolution of 1.15keV FWHM for the scattered electron energy. Threshold settings above 8.2keV were required for stable operation of the trigger. Coincident Compton scatter events in both modules were observed for photons emitted by 57Co source with principal gamma ray energies of 122 and 136keV.

  12. Prototype AEGIS: A Pixel-Array Readout Circuit for Gamma-Ray Imaging

    PubMed Central

    Barber, H. Bradford; Augustine, F. L.; Furenlid, L.; Ingram, C. M.; Grim, G. P.

    2015-01-01

    Semiconductor detector arrays made of CdTe/CdZnTe are expected to be the main components of future high-performance, clinical nuclear medicine imaging systems. Such systems will require small pixel-pitch and much larger numbers of pixels than are available in current semiconductor-detector cameras. We describe the motivation for developing a new readout integrated circuit, AEGIS, for use in hybrid semiconductor detector arrays, that may help spur the development of future cameras. A basic design for AEGIS is presented together with results of an HSPICE™ simulation of the performance of its unit cell. AEGIS will have a shaper-amplifier unit cell and neighbor pixel readout. Other features include the use of a single input power line with other biases generated on-board, a control register that allows digital control of all thresholds and chip configurations and an output approach that is compatible with list-mode data acquisition. An 8×8 prototype version of AEGIS is currently under development; the full AEGIS will be a 64×64 array with 300 μm pitch. PMID:26345126

  13. An interval prototype classifier based on a parameterized distance applied to breast thermographic images.

    PubMed

    Araújo, Marcus C; Souza, Renata M C R; Lima, Rita C F; Filho, Telmo M Silva

    2016-09-15

    Breast cancer is one of the leading causes of death in women. Because of this, thermographic images have received a refocus for diagnosing this cancer type. This work proposes an innovative approach to classify breast abnormalities (malignant, benignant and cyst), employing interval temperature data in order to detect breast cancer. The learning step takes into account the internal variation of the intervals when describing breast abnormalities and uses a way to map these intervals into a space where they can be more easily separated. The method builds class prototypes, and the allocation step is based on a parameterized Mahalanobis distance for interval-valued data. The proposed classifier is applied to a breast thermography dataset from Brazil with 50 patients. We investigate two different scenarios for parameter configuration. The first scenario focuses on the overall misclassification rate and achieves 16 % misclassification rate and 93 % sensitivity to the malignant class. The second scenario maximizes the sensitivity to the malignant class, achieving 100 % sensitivity to this specific class, along with 20 % overall misclassification rate. We compare the performances of our approach and of many methods taken from the literature of interval data classification for the breast thermography task. Results show that our method outperforms competing algorithms.

  14. Section summary: Ground-based field measurements

    Treesearch

    Nophea Sasaki

    2013-01-01

    Although deforestation has been the main focus of international debate in REDD+, forest degradation could emit even more carbon emissions because forest degradation can take place in any accessible forest. Accounting for emission factors requires the use of stockchange or gain-loss approach depending on the forests in questions. Ground based field measurements are a...

  15. Introduction: Photons and ground-based

    NASA Astrophysics Data System (ADS)

    Spann, James; Moore, Thomas

    2017-02-01

    A Conference on Measurement Techniques for Solar and Space Physics was held on 20-24 April 2015 in Boulder, Colorado, at the National Center for Atmospheric Research Center Green Campus. The present volume collects together the conference papers for photons and ground-based categories.

  16. Dietary Assessment on a Mobile Phone Using Image Processing and Pattern Recognition Techniques: Algorithm Design and System Prototyping.

    PubMed

    Probst, Yasmine; Nguyen, Duc Thanh; Tran, Minh Khoi; Li, Wanqing

    2015-07-27

    Dietary assessment, while traditionally based on pen-and-paper, is rapidly moving towards automatic approaches. This study describes an Australian automatic food record method and its prototype for dietary assessment via the use of a mobile phone and techniques of image processing and pattern recognition. Common visual features including scale invariant feature transformation (SIFT), local binary patterns (LBP), and colour are used for describing food images. The popular bag-of-words (BoW) model is employed for recognizing the images taken by a mobile phone for dietary assessment. Technical details are provided together with discussions on the issues and future work.

  17. Dietary Assessment on a Mobile Phone Using Image Processing and Pattern Recognition Techniques: Algorithm Design and System Prototyping

    PubMed Central

    Probst, Yasmine; Nguyen, Duc Thanh; Tran, Minh Khoi; Li, Wanqing

    2015-01-01

    Dietary assessment, while traditionally based on pen-and-paper, is rapidly moving towards automatic approaches. This study describes an Australian automatic food record method and its prototype for dietary assessment via the use of a mobile phone and techniques of image processing and pattern recognition. Common visual features including scale invariant feature transformation (SIFT), local binary patterns (LBP), and colour are used for describing food images. The popular bag-of-words (BoW) model is employed for recognizing the images taken by a mobile phone for dietary assessment. Technical details are provided together with discussions on the issues and future work. PMID:26225994

  18. Silicon carbide optics for space and ground based astronomical telescopes

    NASA Astrophysics Data System (ADS)

    Robichaud, Joseph; Sampath, Deepak; Wainer, Chris; Schwartz, Jay; Peton, Craig; Mix, Steve; Heller, Court

    2012-09-01

    Silicon Carbide (SiC) optical materials are being applied widely for both space based and ground based optical telescopes. The material provides a superior weight to stiffness ratio, which is an important metric for the design and fabrication of lightweight space telescopes. The material also has superior thermal properties with a low coefficient of thermal expansion, and a high thermal conductivity. The thermal properties advantages are important for both space based and ground based systems, which typically need to operate under stressing thermal conditions. The paper will review L-3 Integrated Optical Systems - SSG’s (L-3 SSG) work in developing SiC optics and SiC optical systems for astronomical observing systems. L-3 SSG has been fielding SiC optical components and systems for over 25 years. Space systems described will emphasize the recently launched Long Range Reconnaissance Imager (LORRI) developed for JHU-APL and NASA-GSFC. Review of ground based applications of SiC will include supporting L-3 IOS-Brashear’s current contract to provide the 0.65 meter diameter, aspheric SiC secondary mirror for the Advanced Technology Solar Telescope (ATST).

  19. Results from comparing THEMIS satellite and ground based observations.

    NASA Astrophysics Data System (ADS)

    Mende, Stephen; Frey, Harald; Donovan, Eric; Jackel, Brian; Angelopoulos, V.

    The NASA Time History of Events and Macroscale Interactions during Substorms (THEMIS) project is intended to investigate the major controversy in substorm science, the uncertainty whether the instability leading to the substorm is initiated near the Earth or in the more distant >20 Re magnetic tail. THEMIS will use the timing of the occurrence of substorm signatures at five satellites and at ground based all-sky imagers and magnetometers to infer the propagation direction. The array of stations consists of 20 all-sky imagers and 30 plus magnetometers deployed in the North American continent from Alaska to Labrador. Each ground based observatory contains a white light imager taking auroral images at a 3 second repetition rate and a magnetometer that records the 3 axis variation of the magnetic field at 2 Hz frequency. During the winter of 2007-08 the THEMIS satellites achieved their intended strategic locations to monitor substorms. For example in the time period between 06 and 09 UT on the 2nd of February 2008 several substorms occurred while the THEMIS satellites P1, P2, P3, P4, and P5 were located in the tail of the magnetosphere at approximately 29.6, 18.5, 11, 11 and 8Re downtail distance (GSM) respectively. The weather was relatively clear permitting the recording of the auroral features while the particle and field measurements were taken. In this paper we will discuss the preliminary results drawn from the data taken during substorms that occur during THEMIS conjunctions.

  20. Starshade Prototype

    NASA Image and Video Library

    2016-08-09

    This image shows the bare bones of the first prototype starshade by NASA's Jet Propulsion Laboratory, Pasadena, California. The prototype was shown in technology partner Astro Aerospace/Northrup Grumman's facility in Santa Barbara, California in 2013. In order for the petals of the starshade to diffract starlight away from the camera of a space telescope, they must be deployed with accuracy once the starshade reaches space. The four petals pictured in the image are being measured for this positional accuracy with a laser. As shown by this 66-foot (20-meter) model, starshades can come in many shapes and sizes. This design shows petals that are more extreme in shape which properly diffracts starlight for smaller telescopes. http://photojournal.jpl.nasa.gov/catalog/PIA20903

  1. SU-C-209-05: Monte Carlo Model of a Prototype Backscatter X-Ray (BSX) Imager for Projective and Selective Object-Plane Imaging

    SciTech Connect

    Rolison, L; Samant, S; Baciak, J; Jordan, K

    2016-06-15

    Purpose: To develop a Monte Carlo N-Particle (MCNP) model for the validation of a prototype backscatter x-ray (BSX) imager, and optimization of BSX technology for medical applications, including selective object-plane imaging. Methods: BSX is an emerging technology that represents an alternative to conventional computed tomography (CT) and projective digital radiography (DR). It employs detectors located on the same side as the incident x-ray source, making use of backscatter and avoiding ring geometry to enclose the imaging object. Current BSX imagers suffer from low spatial resolution. A MCNP model was designed to replicate a BSX prototype used for flaw detection in industrial materials. This prototype consisted of a 1.5mm diameter 60kVp pencil beam surrounded by a ring of four 5.0cm diameter NaI scintillation detectors. The imaging phantom consisted of a 2.9cm thick aluminum plate with five 0.6cm diameter holes drilled halfway. The experimental image was created using a raster scanning motion (in 1.5mm increments). Results: A qualitative comparison between the physical and simulated images showed very good agreement with 1.5mm spatial resolution in plane perpendicular to incident x-ray beam. The MCNP model developed the concept of radiography by selective plane detection (RSPD) for BSX, whereby specific object planes can be imaged by varying kVp. 10keV increments in mean x-ray energy yielded 4mm thick slice resolution in the phantom. Image resolution in the MCNP model can be further increased by increasing the number of detectors, and decreasing raster step size. Conclusion: MCNP modelling was used to validate a prototype BSX imager and introduce the RSPD concept, allowing for selective object-plane imaging. There was very good visual agreement between the experimental and MCNP imaging. Beyond optimizing system parameters for the existing prototype, new geometries can be investigated for volumetric image acquisition in medical applications. This material is

  2. Prototype of annotation tools for microscopic digital images on Android devices

    NASA Astrophysics Data System (ADS)

    Muhimmah, I.; Nugraha, D. DC

    2016-01-01

    Reading a slide under a microscope manually is very complicated. An expert may spend 3-4 hours to read a single slide. Moreover, the intra- and inter-observer variability is known to be high. This prototype was developed to simplify the slide-reading process on Android devices in order to accelerate the reading process and generate more accurate information.The prototype allows users to annotate the boundaries of an object. Moreover, the proposed prototype has successfully reconstructed multiple object boundaries into simple closed curves from a limited amount of user input.Thecoordinates of the annotated objects are stored in a text file (*.txt) that can be usedfor further analysis.The prototype's performance with respect to time and memory usage are included.

  3. Ground-based observations of exoplanet atmospheres

    NASA Astrophysics Data System (ADS)

    de Mooij, Ernst Johan Walter

    2011-11-01

    This thesis focuses on the properties of exoplanet atmospheres. The results for ground-based near-infrared secondary eclipse observations of three different exoplanets, TrES-3b, HAT-P-1b and WASP-33b, are presented which have been obtained with ground-based telescopes as part of the GROUSE project. In addition to secondary eclipse observations, the broadband transmission spectrum of the super-Earth GJ1214b is also presented. The transmission spectrum for this low-density planet indicates that it probably has a low-metallicity, hydrogen dominated atmosphere. Finally the results for an ensemble study of the thermal emission properties of hot Jupiters is presented, including the average spectrum for these planets separated based on the level of incident radiation and the activity of their host-stars.

  4. MSFC Skylab ground-based astronomy program

    NASA Technical Reports Server (NTRS)

    Duncan, B. J.

    1974-01-01

    The Skylab Ground-Based Astronomy Program (SGAP) was conducted to enhance the data base of solar physics obtained during the Apollo Telescope Mount (ATM) mission flown in conjunction with the Skylab orbital station. Leading solar physicists from various observatories obtained data from the ground at the same time that orbital data were being acquired by ATM. The acquisition of corollary solar data from the ground simultaneously with the ATM orbital observations helped to provide a broader basis for understanding solar physics by increasing spectral coverage and by the use of additional sophisticated instruments of various types. This report briefly describes the individual tasks and the associated instrumentation selected for this ground-based program and contains as appendices, the final reports from the Principal Investigators.

  5. Space and Ground-Based Infrastructures

    NASA Astrophysics Data System (ADS)

    Weems, Jon; Zell, Martin

    This chapter deals first with the main characteristics of the space environment, outside and inside a spacecraft. Then the space and space-related (ground-based) infrastructures are described. The most important infrastructure is the International Space Station, which holds many European facilities (for instance the European Columbus Laboratory). Some of them, such as the Columbus External Payload Facility, are located outside the ISS to benefit from external space conditions. There is only one other example of orbital platforms, the Russian Foton/Bion Recoverable Orbital Capsule. In contrast, non-orbital weightless research platforms, although limited in experimental time, are more numerous: sounding rockets, parabolic flight aircraft, drop towers and high-altitude balloons. In addition to these facilities, there are a number of ground-based facilities and space simulators, for both life sciences (for instance: bed rest, clinostats) and physical sciences (for instance: magnetic compensation of gravity). Hypergravity can also be provided by human and non-human centrifuges.

  6. Test of a conceptual prototype of the total internal reflection Cherenkov imaging detector (DIRC) with cosmic muons

    SciTech Connect

    Aston, D.; Kawahara, H.; McShurley, D.; Muller, D.; Oxoby, G.; Hearty, C.; Kadyk, J.; Lynch, G.; Lu, A.

    1994-12-01

    The DIRC is a totally internally reflecting Cherenkov imaging detector proposed for particle identification at the asymmetric e{sup +}e{sup {minus}} B factories. First test results from a conceptual prototype using cosmic muons are reported. The photo-electron yield and the single Cherenkov photon resolution at various track dip angles and positions along the radiator bar have been measured. The results are consistent with estimates and Monte-Carlo simulations.

  7. Ground based spectroscopy of hot Jupiters

    NASA Astrophysics Data System (ADS)

    Waldmann, Ingo

    2010-05-01

    It has been shown in recent years with great success that spectroscopy of exoplanetary atmospheres is feasible using space based observatories such as the HST and Spitzer. However, with the end of the Spitzer cold-phase, space based observations in the near to mid infra-red are limited, which will remain true until the the onset of the JWST. The importance of developing methods of ground based spectroscopic analysis of known hot Jupiters is therefore apparent. In the past, various groups have attempted exoplanetary spectroscopy using ground based facilities and various techniques. Here I will present results using a novel spectral retrieval method for near to mid infra-red emission and transmission spectra of exoplanetary atmospheres taken from the ground and discuss the feasibility of future ground-based spectroscopy in a broader context. My recently commenced PhD project is under the supervision of Giovanna Tinetti (University College London) and in collaboration with J. P. Beaulieu (Institut d'Astrophysique de Paris), Mark Swain and Pieter Deroo (Jet Propulsion Laboratory, Caltech).

  8. Portfolio: a prototype workstation for development and evaluation of tools for analysis and management of digital portal images.

    PubMed

    Boxwala, A A; Chaney, E L; Fritsch, D S; Friedman, C P; Rosenman, J G

    1998-09-01

    The purpose of this investigation was to design and implement a prototype physician workstation, called PortFolio, as a platform for developing and evaluating, by means of controlled observer studies, user interfaces and interactive tools for analyzing and managing digital portal images. The first observer study was designed to measure physician acceptance of workstation technology, as an alternative to a view box, for inspection and analysis of portal images for detection of treatment setup errors. The observer study was conducted in a controlled experimental setting to evaluate physician acceptance of the prototype workstation technology exemplified by PortFolio. PortFolio incorporates a windows user interface, a compact kit of carefully selected image analysis tools, and an object-oriented data base infrastructure. The kit evaluated in the observer study included tools for contrast enhancement, registration, and multimodal image visualization. Acceptance was measured in the context of performing portal image analysis in a structured protocol designed to simulate clinical practice. The acceptability and usage patterns were measured from semistructured questionnaires and logs of user interactions. Radiation oncologists, the subjects for this study, perceived the tools in PortFolio to be acceptable clinical aids. Concerns were expressed regarding user efficiency, particularly with respect to the image registration tools. The results of our observer study indicate that workstation technology is acceptable to radiation oncologists as an alternative to a view box for clinical detection of setup errors from digital portal images. Improvements in implementation, including more tools and a greater degree of automation in the image analysis tasks, are needed to make PortFolio more clinically practical.

  9. Ground-Based Telescope Parametric Cost Model

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Rowell, Ginger Holmes

    2004-01-01

    A parametric cost model for ground-based telescopes is developed using multi-variable statistical analysis, The model includes both engineering and performance parameters. While diameter continues to be the dominant cost driver, other significant factors include primary mirror radius of curvature and diffraction limited wavelength. The model includes an explicit factor for primary mirror segmentation and/or duplication (i.e.. multi-telescope phased-array systems). Additionally, single variable models based on aperture diameter are derived. This analysis indicates that recent mirror technology advances have indeed reduced the historical telescope cost curve.

  10. Petascale Computing for Ground-Based Solar Physics with the DKIST Data Center

    NASA Astrophysics Data System (ADS)

    Berukoff, Steven J.; Hays, Tony; Reardon, Kevin P.; Spiess, DJ; Watson, Fraser; Wiant, Scott

    2016-05-01

    When construction is complete in 2019, the Daniel K. Inouye Solar Telescope will be the most-capable large aperture, high-resolution, multi-instrument solar physics facility in the world. The telescope is designed as a four-meter off-axis Gregorian, with a rotating Coude laboratory designed to simultaneously house and support five first-light imaging and spectropolarimetric instruments. At current design, the facility and its instruments will generate data volumes of 3 PB per year, and produce 107-109 metadata elements.The DKIST Data Center is being designed to store, curate, and process this flood of information, while providing association of science data and metadata to its acquisition and processing provenance. The Data Center will produce quality-controlled calibrated data sets, and make them available freely and openly through modern search interfaces and APIs. Documented software and algorithms will also be made available through community repositories like Github for further collaboration and improvement.We discuss the current design and approach of the DKIST Data Center, describing the development cycle, early technology analysis and prototyping, and the roadmap ahead. We discuss our iterative development approach, the underappreciated challenges of calibrating ground-based solar data, the crucial integration of the Data Center within the larger Operations lifecycle, and how software and hardware support, intelligently deployed, will enable high-caliber solar physics research and community growth for the DKIST's 40-year lifespan.

  11. Prototype vein contrast enhancer

    NASA Astrophysics Data System (ADS)

    Zeman, Herbert D.; Lovhoiden, Gunnar; Vrancken, Carlos

    2004-07-01

    A proof-of-principle prototype Vein Contrast Enhancer (VCE) has been designed and constructed. The VCE is an instrument that makes vein access easier by capturing an infrared image of peripheral veins, enhancing the vein-contrast using software image processing, and projecting the enhanced vein-image back onto the skin using a modified commercial projector. The prototype uses software alignment to achieve alignment accuracy between the captured infrared image and the projected visible image of better than 0.06 mm. Figure 1 shows the prototype demonstrated in our laboratory.

  12. Design and prototype of radar sensor with Vivaldi linear array for through-wall radar imaging: an experimental study

    NASA Astrophysics Data System (ADS)

    Yılmaz, Betül; Özdemir, Caner

    2016-10-01

    We present a radar sensor that was designed to detect and image moving objects/targets on the other side of a wall. The radar sensor was composed of a linear array of Vivaldi antenna elements, an radio frequency (RF) switch, a microcontroller unit, and an RF transceiver. For the linear array, a total of eight antenna elements were used as sensors in synthetic aperture radar (SAR) configuration in the cross-range axis to improve the resolution in this dimension. Design steps of Vivaldi antenna elements and the entire linear array were presented. After the design, the prototyping procedure and the details of the radar sensor were given. Through-the-wall radar (TWR) imaging experiments were performed for stationary and moving targets using the assembled sensor. The resultant TWR images after these experiments were presented. During the image formation, a back-projection type image focusing algorithm was implemented and applied to increase the signal-to-noise ratio of the raw images. The constructed radar images demonstrated that our radar sensor could successfully detect and image both stationary and moving targets on the other side of the wall.

  13. Archiving data from ground-based telescopes

    NASA Technical Reports Server (NTRS)

    Albrecht, M. A.

    1992-01-01

    The scientific throughput of a particular observing facility has been demonstrated to be multiplied with the operation of a data archive and its corresponding retrieval system. A requisite to achieve such an exploitation is a well structured observations catalog, i.e. a catalog that includes all information necessary to reduce and analyze the data even many years after its acquisition. At the same time, an information system is required that allow users to browse through the catalog at different levels of detail, adapting the amount of information presented to the actual needs of the user. Archiving data acquired with ground-based telescopes is particularly difficult because of the relative short life-time of instruments and detectors in comparison to the expected life-time of the archive. This feature differentiates ground-based originated archives radically from its spaceborne counterparts. The organization of the observations catalog becomes highly dependent on the capability of the archive to deal with new instrumental configurations. We introduce in this paper, the concept of a catalog database as opposed to the static catalog design currently in use in many archiving facilities, as a method to deal with this problem. We also present a brief review of activities currently in progress in this area.

  14. Augmenting WFIRST Microlensing with a Ground-Based Telescope Network

    NASA Astrophysics Data System (ADS)

    Zhu, Wei; Gould, Andrew

    2016-06-01

    Augmenting the Wide Field Infrared Survey Telescope (WFIRST) microlensing campaigns with intensive observations from a ground-based network of wide-field survey telescopes would have several major advantages. First, it would enable full two-dimensional (2-D) vector microlens parallax measurements for a substantial fraction of low-mass lenses as well as planetary and binary events that show caustic crossing features. For a significant fraction of the free-floating planet (FFP) events and all caustic-crossing planetary/binary events, these 2-D parallax measurements directly lead to complete solutions (mass, distance, transverse velocity) of the lens object (or lens system). For even more events, the complementary ground-based observations will yield 1-D parallax measurements. Together with the 1-D parallaxes from WFIRST alone, they can probe the entire mass range M > M_Earth. For luminous lenses, such 1-D parallax measurements can be promoted to complete solutions (mass, distance, transverse velocity) by high-resolution imaging. This would provide crucial information not only about the hosts of planets and other lenses, but also enable a much more precise Galactic model. Other benefits of such a survey include improved understanding of binaries (particularly with low mass primaries), and sensitivity to distant ice-giant and gas-giant companions of WFIRST lenses that cannot be detected by WFIRST itself due to its restricted observing windows. Existing ground-based microlensing surveys can be employed if WFIRST is pointed at lower-extinction fields than is currently envisaged. This would come at some cost to the event rate. Therefore the benefits of improved characterization of lenses must be weighed against these costs.

  15. Frequency domain and full waveform time domain inversion of ground based magnetometer, electrometer and incoherent scattering radar arrays to image strongly heterogenous 3-D Earth structure, ionospheric structure, and to predict the intensity of GICs in the power grid

    NASA Astrophysics Data System (ADS)

    Schultz, A.; Imamura, N.; Bonner, L. R., IV; Cosgrove, R. B.

    2016-12-01

    Ground-based magnetometer and electrometer arrays provide the means to probe the structure of the Earth's interior, the interactions of space weather with the ionosphere, and to anticipate the intensity of geomagnetically induced currents (GICs) in power grids. We present a local-to-continental scale view of a heterogeneous 3-D crust and mantle as determined from magnetotelluric (MT) observations across arrays of ground-based electric and magnetic field sensors. MT impedance tensors describe the relationship between electric and magnetic fields at a given site, thus implicitly they contain all known information on the 3-D electrical resistivity structure beneath and surrounding that site. By using multivariate transfer functions to project real-time magnetic observatory network data to areas surrounding electric power grids, and by projecting those magnetic fields through MT impedance tensors, the projected magnetic field can be transformed into predictions of electric fields along the path of the transmission lines, an essential element of predicting the intensity of GICs in the grid. Finally, we explore GICs, i.e. Earth-ionosphere coupling directly in the time-domain. We consider the fully coupled EM system, where we allow for a non-stationary ionospheric source field of arbitrary complexity above a 3-D Earth. We solve the simultaneous inverse problem for 3-D Earth conductivity and source field structure directly in the time domain. In the present work, we apply this method to magnetotelluric data obtained from a synchronously operating array of 25 MT stations that collected continuous MT waveform data in the interior of Alaska during the autumn and winter of 2015 under the footprint of the Poker Flat (Alaska) Incoherent Scattering Radar (PFISR). PFISR data yield functionals of the ionospheric electric field and ionospheric conductivity that constrain the MT source field. We show that in this region conventional robust MT processing methods struggle to produce

  16. In vivo testing of a prototype system providing simultaneous white light and near infrared autofluorescence image acquisition for detection of bladder cancer.

    PubMed

    Jacobson, Michael C; deVere White, Ralph; Demos, Stavros G

    2012-03-01

    A prototype instrument developed to provide simultaneously ordinary visual endoscopy together with near infrared (NIR) autofluorescence imaging via parallel image acquisition is demonstrated. The two images are recorded concurrently and the instrument interfaces with any ordinary endoscope. Preliminary results of a pilot study focused on imaging of bladder tumors in vivo using this instrumentation are presented. The experimental results demonstrate the capabilities of this instrumentation design, imaging methodology, and define the current limitation for further development of the system.

  17. Study of Trade Wind Clouds Using Ground Based Stereo Cameras

    NASA Astrophysics Data System (ADS)

    Porter, J.

    2010-12-01

    We employ ground based stereo cameras to derive the three dimensional position of trade wind clouds features. The process employs both traditional and novel methods. The stereo cameras are calibrated for orientation using the sun as a geo-reference point at several times throughout the day. Spatial correlation is used to detect similar cloud features in both camera images and a simultaneous-differential equation is solved to get the best cloud position for the given rays from the cameras to the cloud feature. Once the positions of the clouds are known in three-dimensional space, then it is also possible to derive upper level wind speed and direction by tracking the position of clouds in space and time. The vector winds can be obtained at many locations and heights in a cone region over the surface site. The accuracy of the measurement depends on the camera separation with a trade-off occurring at different camera separations and cloud ranges. The system design and performance will be discussed along with field observations. This approach provides a new way to study clouds for climate change efforts. It also provides an inexpensive way to measure upper level wind fields in cloudy regions. Ground based stereo cameras are used to derive cloud position in space a time.

  18. Mirror-Imaged Rapid Prototype Skull Model and Pre-Molded Synthetic Scaffold to Achieve Optimal Orbital Cavity Reconstruction.

    PubMed

    Park, Sung Woo; Choi, Jong Woo; Koh, Kyung S; Oh, Tae Suk

    2015-08-01

    Reconstruction of traumatic orbital wall defects has evolved to restore the original complex anatomy with the rapidly growing use of computer-aided design and prototyping. This study evaluated a mirror-imaged rapid prototype skull model and a pre-molded synthetic scaffold for traumatic orbital wall reconstruction. A single-center retrospective review was performed of patients who underwent orbital wall reconstruction after trauma from 2012 to 2014. Patients were included by admission through the emergency department after facial trauma or by a tertiary referral for post-traumatic orbital deformity. Three-dimensional (3D) computed tomogram-based mirror-imaged reconstruction images of the orbit and an individually manufactured rapid prototype skull model by a 3D printing technique were obtained for each case. Synthetic scaffolds were anatomically pre-molded using the skull model as guide and inserted at the individual orbital defect. Postoperative complications were assessed and 3D volumetric measurements of the orbital cavity were performed. Paired samples t test was used for statistical analysis. One hundred four patients with immediate orbital defect reconstructions and 23 post-traumatic orbital deformity reconstructions were included in this study. All reconstructions were successful without immediate postoperative complications, although there were 10 cases with mild enophthalmos and 2 cases with persistent diplopia. Reoperations were performed for 2 cases of persistent diplopia and secondary touchup procedures were performed to contour soft tissue in 4 cases. Postoperative volumetric measurement of the orbital cavity showed nonsignificant volume differences between the damaged orbit and the reconstructed orbit (21.35 ± 1.93 vs 20.93 ± 2.07 cm(2); P = .98). This protocol was extended to severe cases in which more than 40% of the orbital frame was lost and combined with extensive soft tissue defects. Traumatic orbital reconstruction can be optimized and

  19. SSPI - Space Service Provider Infrastructure: Image Information Mining and Management Prototype for a Distributed Environment

    NASA Astrophysics Data System (ADS)

    Candela, L.; Ruggieri, G.; Giancaspro, A.

    2004-09-01

    In the sphere of "Multi-Mission Ground Segment" Italian Space Agency project, some innovative technologies such as CORBA[1], Z39.50[2], XML[3], Java[4], Java server Pages[4] and C++ has been experimented. The SSPI system (Space Service Provider Infrastructure) is the prototype of a distributed environment aimed to facilitate the access to Earth Observation (EO) data. SSPI allows to ingests, archive, consolidate, visualize and evaluate these data. Hence, SSPI is not just a database of or a data repository, but an application that by means of a set of protocols, standards and specifications provides a unified access to multi-mission EO data.

  20. Interactive image-guided surgery system with high-performance computing capabilities on low-cost workstations: a prototype.

    PubMed

    Roldan, P; Barcia-Salorio, J L; Talamantes, F; Alcañiz, M; Grau, V; Monserrat, C; Juan, C

    1999-01-01

    We present a new frameless stereotatic system prototype that has been initially validated in functional neurosurgery operations and that makes use of an optical position tracker for image-guided neurosurgery. Several devices for tracking different surgical instruments have been designed and manufactured. These devices include an array of infrared light-emitting diodes that are tracked by three charge-coupled device cameras. The system presents several new approaches for surgery planning. For high-quality 3D images of the patient's anatomy, we have developed a parallel version of a volume-rendering algorithm, thus enabling real-time 3D anatomy manipulation on low-cost PC workstations. In order to test the accuracy of the system, the localization of the target by means of a stereotatic frame has been compared with frameless techniques, obtaining a difference of about 1 +/- 1 mm. Copyright 2000 S. Karger AG, Basel

  1. The accuracy of solid model and rapid prototype of prostheses in comparison to the digital CT image data

    NASA Astrophysics Data System (ADS)

    Suwandi, Agri; Kiswanto, Gandjar; Kusumaningsih, Widjajalaksmi; Soemardi, Tresna P.

    2017-02-01

    Prostheses are a derivative of biomedical products that have important things, which are: a design, size and bio compatible material. To produce optimum prostheses, safe and comfortable use, it would require design a model that fits the size of the patient's anatomy. In this paper describes the accuracy of solid model and rapid prototype of prostheses in comparison to the digital CT image data. Where the main parameters used as the reference measurement is digital CT image data. The data were analyzed using a statistical method to get the standard deviation of the comparison parameters of the data obtained, so that it can be known how the accuracy of the measurement results of each data.

  2. A system for rapid prototyping of hearts with congenital malformations based on the medical imaging interaction toolkit (MITK)

    NASA Astrophysics Data System (ADS)

    Wolf, Ivo; Böttger, Thomas; Rietdorf, Urte; Maleike, Daniel; Greil, Gerald; Sieverding, Ludger; Miller, Stephan; Mottl-Link, Sibylle; Meinzer, Hans-Peter

    2006-03-01

    Precise knowledge of the individual cardiac anatomy is essential for diagnosis and treatment of congenital heart disease. Complex malformations of the heart can best be comprehended not from images but from anatomic specimens. Physical models can be created from data using rapid prototyping techniques, e.g., lasersintering or 3D-printing. We have developed a system for obtaining data that show the relevant cardiac anatomy from high-resolution CT/MR images and are suitable for rapid prototyping. The challenge is to preserve all relevant details unaltered in the produced models. The main anatomical structures of interest are the four heart cavities (atria, ventricles), the valves and the septum separating the cavities, and the great vessels. These can be shown either by reproducing the morphology itself or by producing a model of the blood-pool, thus creating a negative of the morphology. Algorithmically the key issue is segmentation. Practically, possibilities allowing the cardiologist or cardiac surgeon to interactively check and correct the segmentation are even more important due to the complex, irregular anatomy and imaging artefacts. The paper presents the algorithmic and interactive processing steps implemented in the system, which is based on the open-source Medical Imaging Interaction Toolkit (MITK, www.mitk.org). It is shown how the principles used in MITK enable to assemble the system from modules (functionalities) developed independently from each other. The system allows to produce models of the heart (and other anatomic structures) of individual patients as well as to reproduce unique specimens from pathology collections for teaching purposes.

  3. Airborne prototype instrument suite test flight of a low-light high-dynamic range imager and visible spectrometer

    NASA Astrophysics Data System (ADS)

    Kuester, Michele A.; Lasnik, James K.; Ramond, Tanya; Lin, Tony; Johnson, Brian; Kaptchen, Paul; Good, William

    2007-09-01

    The Airborne Sensors Initiative (ASI) at Ball Aerospace and Technologies Corp. (BATC) specializes in airborne demonstration of internally-developed instrument concepts and innovative remote sensing technologies. In December 2006, ASI flew an environmental remote sensing suite consisting of the Low Light Imager (LLI) and Prototype Airborne Visible Imaging Spectrometer (PAVIS), both of which are operated using a pushbroom approach. LLI is designed for nighttime or high dynamic range imaging. It is capable of yielding 10 7 dynamic range and offers quality images amid illumination extending from a 1/ 4 moon to full sunlight and with autonomous operation. PAVIS is an imaging spectrometer based on the Dyson design and exhibits a 200 nm spectral bandwidth tunable within 400 - 850 nm. Developed internally to demonstrate promising remote sensing capabilities, these small, low-mass and low-power instruments are prepared for aircraft flight and are currently being used in the field to acquire scientific data. The LLI/PAVIS instrument suite has been utilized to collect airborne urban and rural imagery, as well as spectral information about the Great Salt Lake area, western Colorado, and ancient lava flows in southern Idaho. Highlights of the instrument design and ensuing data from previous flights are presented herein.

  4. Deployment of a Prototype Plant GFP Imager at the Arthur Clarke Mars Greenhouse of the Haughton Mars Project

    PubMed Central

    Paul, Anna-Lisa; Bamsey, Matthew; Berinstain, Alain; Braham, Stephen; Neron, Philip; Murdoch, Trevor; Graham, Thomas; Ferl, Robert J.

    2008-01-01

    The use of engineered plants as biosensors has made elegant strides in the past decades, providing keen insights into the health of plants in general and particularly in the nature and cellular location of stress responses. However, most of the analytical procedures involve laboratory examination of the biosensor plants. With the advent of the green fluorescence protein (GFP) as a biosensor molecule, it became at least theoretically possible for analyses of gene expression to occur telemetrically, with the gene expression information of the plant delivered to the investigator over large distances simply as properly processed fluorescence images. Spaceflight and other extraterrestrial environments provide unique challenges to plant life, challenges that often require changes at the gene expression level to accommodate adaptation and survival. Having previously deployed transgenic plant biosensors to evaluate responses to orbital spaceflight, we wished to develop the plants and especially the imaging devices required to conduct such experiments robotically, without operator intervention, within extraterrestrial environments. This requires the development of an autonomous and remotely operated plant GFP imaging system and concomitant development of the communications infrastructure to manage dataflow from the imaging device. Here we report the results of deploying a prototype GFP imaging system within the Arthur Clarke Mars Greenhouse (ACMG) an autonomously operated greenhouse located within the Haughton Mars Project in the Canadian High Arctic. Results both demonstrate the applicability of the fundamental GFP biosensor technology and highlight the difficulties in collecting and managing telemetric data from challenging deployment environments. PMID:27879848

  5. Deployment of a Prototype Plant GFP Imager at the Arthur Clarke Mars Greenhouse of the Haughton Mars Project.

    PubMed

    Paul, Anna-Lisa; Bamsey, Matthew; Berinstain, Alain; Braham, Stephen; Neron, Philip; Murdoch, Trevor; Graham, Thomas; Ferl, Robert J

    2008-04-18

    The use of engineered plants as biosensors has made elegant strides in the past decades, providing keen insights into the health of plants in general and particularly in the nature and cellular location of stress responses. However, most of the analytical procedures involve laboratory examination of the biosensor plants. With the advent of the green fluorescence protein (GFP) as a biosensor molecule, it became at least theoretically possible for analyses of gene expression to occur telemetrically, with the gene expression information of the plant delivered to the investigator over large distances simply as properly processed fluorescence images. Spaceflight and other extraterrestrial environments provide unique challenges to plant life, challenges that often require changes at the gene expression level to accommodate adaptation and survival. Having previously deployed transgenic plant biosensors to evaluate responses to orbital spaceflight, we wished to develop the plants and especially the imaging devices required to conduct such experiments robotically, without operator intervention, within extraterrestrial environments. This requires the development of an autonomous and remotely operated plant GFP imaging system and concomitant development of the communications infrastructure to manage dataflow from the imaging device. Here we report the results of deploying a prototype GFP imaging system within the Arthur Clarke Mars Greenhouse (ACMG) an autonomously operated greenhouse located within the Haughton Mars Project in the Canadian High Arctic. Results both demonstrate the applicability of the fundamental GFP biosensor technology and highlight the difficulties in collecting and managing telemetric data from challenging deployment environments.

  6. Prototype study on a miniaturized dual-modality imaging system for photoacoustic microscopy and confocal fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Chen, Sung-Liang; Xie, Zhixing; Guo, L. Jay; Wang, Xueding

    2014-03-01

    It is beneficial to study tumor angiogenesis and microenvironments by imaging the microvasculature and cells at the same time. Photoacoustic microscopy (PAM) is capable of sensitive three-dimensional mapping of microvasculature, while fluorescence microscopy may be applied to assessment of tissue pathology. In this work, a fiber-optic based PAM and confocal fluorescence microscopy (CFM) dual-modality imaging system was designed and built, serving as a prototype of a miniaturized dual-modality imaging probe for endoscopic applications. As for the design, we employed miniature components, including a microelectromechanical systems (MEMS) scanner, a miniature objective lens, and a small size optical microring resonator as an acoustic detector. The system resolutions were calibrated as 8.8 μm in the lateral directions for both PAM and CFM, and 19 μm and 53 μm in the axial direction for PAM and CFM, respectively. Images of the animal bladders ex vivo were demonstrated to show the ability of the system in imaging not only microvasculature but also cellular structure.

  7. Automatically designing an image processing pipeline for a five-band camera prototype using the local, linear, learned (L3) method

    NASA Astrophysics Data System (ADS)

    Tian, Qiyuan; Blasinski, Henryk; Lansel, Steven; Jiang, Haomiao; Fukunishi, Munenori; Farrell, Joyce E.; Wandell, Brian A.

    2015-02-01

    The development of an image processing pipeline for each new camera design can be time-consuming. To speed camera development, we developed a method named L3 (Local, Linear, Learned) that automatically creates an image processing pipeline for any design. In this paper, we describe how we used the L3 method to design and implement an image processing pipeline for a prototype camera with five color channels. The process includes calibrating and simulating the prototype, learning local linear transforms and accelerating the pipeline using graphics processing units (GPUs).

  8. Aluminium Mirrors: An Alternative for Ground Based Cherenkov Telescopes

    NASA Astrophysics Data System (ADS)

    Aye, K.-M.; Chadwick, P. M.; Hadjichristidis, C. N.; Latham, I. J.; Le Gallou, R.; McComb, T. J. L.; McKenny, J. M.; Orford, K. J.; Osborne, J. L.; Noutsos, A.; Rayner, S. M.

    2003-07-01

    We present a novel alternative to the use of glass mirrors on ground based Cherenkov telescopes. Glass mirrors, whilst having excellent imaging characteristics, can become a limiting factor in the design of such telescopes, due to their weight and expense. We produce mirrors using an innovative vacuum forming process (global patent applied for), using only aluminium materials. The result is a mirror weighing and costing a fraction of that of a glass mirror. The method of production is described together with preliminary results of the shape conformity and repro ducibility. The properties of the reflective surface are outlined, including robustness and specular reflectivity. This is shown to be superior to its glass equivalent particularly at wavelengths relevant to Cherenkov radiation.

  9. Quantitative analysis of contrast to noise ratio using a phase contrast x-ray imaging prototype

    NASA Astrophysics Data System (ADS)

    Ghani, Muhammad U.; Wu, Di; Li, Yuhua; Kang, Minhua; Chen, Wei R.; Wu, Xizeng; Liu, Hong

    2013-02-01

    The purpose of this study was to determine the Contrast to Noise Ratio (CNR) of the x-ray images taken with the phase contrast imaging mode and compare them with the CNR of the images taken under the conventional mode. For each mode, three images were taken under three exposure conditions of 100 kVp (2.8mAs), 120 kVp (1.9mAs) and 140kVp (1.42mAs). A 1.61cm thick contrast detail phantom was used as an imaging object. For phase contrast, the source to image detector distance (SID) was 182.88 cm and the source to object (SOD) distance was 73.15 cm. The SOD was the same as SID in the conventional imaging mode. A computed radiography (CR) plate was used as a detector and the output CR images were converted to linear form in relation with the incident x-ray exposure. To calculate CNR, an image processing software was used to determine the mean pixel value and the standard deviation of the pixels in the region of interest (ROI) and in the nearby background around ROI. At any given exposure condition investigated in this study, the CNR values for the phase contrast images were better as compared to the corresponding conventional mode images. The superior image quality in terms of CNR is contributed by the phase-shifts resulted contrast, as well as the reduced scatters due to the air gap between the object and the detector.

  10. Prototype imaging protocols for monitoring the efficacy of iodine-131 ablation in differentiated thyroid cancer.

    PubMed

    Kobayashi, Masato; Wakabayashi, Hiroshi; Kojima, Hironori; Konishi, Takahiro; Okuda, Koichi; Yoneyama, Hiroto; Kayano, Daiki; Tobisaka, Minoru; Tsushima, Hiroyuki; Onoguchi, Masahisa; Kawai, Keiichi; Kinuya, Seigo

    2013-01-01

    Whole-body and single photon emission tomography (SPET) images during sodium iodide-131 (Na131I) ablation are useful to confirm the efficacy of ablation using 131I imaging. However, there have been no attempts to improve the quality of 131I imaging. We therefore investigated imaging protocols for 131I imaging in differentiated thyroid cancer (DTC). Phantoms containing 131I were used to simulate extra-thyroid beds and thyroid beds. To simulate extra-thyroid beds, a phantom containing 0.19, 0.37, 0.74 or 1.85 MBq was placed in the acquisition center. To simulate the thyroid beds, four phantoms were applied as normal thyroid tissue, and four phantoms containing 0.19, 0.37, 0.74 and 1.85 MBq were arranged around normal thyroid tissue as a cancer. Whole-body imaging was performed at different table speeds, and SPET data acquired with various pixel sizes were reconstructed using a filtered backed projection (FBP) and ordered-subsets expectation maximization with 3-dimensional (OSEM-3D) algorithm. We measured full width at half maximum (FWHM) and % coefficient of variation (%CV). Patients were then examined based on the results of phantom studies. In extrathyroid beds, slower table speed in whole-body imaging improved %CV, but had little effect on FWHM. For SPET imaging OSEM-3D produced high-resolution and low-noise images, and FWHM and %CV improved with smaller pixel size, as compared with FBP. In the thyroid beds, only the 1.85 MBq phantom could be confirmed on whole-body imaging. Images by SPET had high FWHM and low %CV when the smaller pixel size and OSEM-3D were applied. Accumulation of ≤1.85 MBq was detected with a smaller pixel size of ≤4.8 mm and OSEM-3D. For Na131I ablation imaging, slower scan speed is suitable for whole-body imaging and smaller pixel size and OSEM-3D is appropriate for SPET imaging. In conclusion, we confirmed Na131I accumulation in thyroid beds using slower scan speed (≤15 cm/min) on whole-body imaging, and then accurate identification

  11. SCIENTIFIC EFFICIENCY OF GROUND-BASED TELESCOPES

    SciTech Connect

    Abt, Helmut A.

    2012-10-01

    I scanned the six major astronomical journals of 2008 for all 1589 papers that are based on new data obtained from ground-based optical/IR telescopes worldwide. Then I collected data on numbers of papers, citations to them in 3+ years, the most-cited papers, and annual operating costs. These data are assigned to four groups by telescope aperture. For instance, while the papers from telescopes with an aperture >7 m average 1.29 more citations than those with an aperture of 2 to <4 m, this represents a small return for a factor of four difference in operating costs. Among the 17 papers that have received {>=}100 citations in 3+ years, only half come from the large (>7 m) telescopes. I wonder why the large telescopes do so relatively poorly and suggest possible reasons. I also found that papers based on archival data, such as the Sloan Digital Sky Survey, produce 10.6% as many papers and 20.6% as many citations as those based on new data. Also, the 577.2 papers based on radio data produced 36.3% as many papers and 33.6% as many citations as the 1589 papers based on optical/IR telescopes.

  12. Ground based research in microgravity materials processing

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Rathz, Tom

    1994-01-01

    The core activities performed during this time period have been concerned with tracking the TEMPEST experiments on the shuttle with drops of Zr, Ni, and Nb alloys. In particular a lot of Zr drops are being made to better define the recalescence characteristics of that system so that accurate comparisons of the drop tube results with Tempest can be made. A new liner, with minimal reflectivity characteristics, has been inserted into the drop tube in order to improve the recalescence measurements of the falling drops. The first installation to make the geometric measurements to ensure a proper fit has been made. The stovepipe sections are currently in the shop at MSFC being painted with low reflectivity black paint. Work has also continued on setting up the MEL apparatus obtained from Oak Ridge in the down stairs laboratory at the Drop Tube Facilities. Some ground-based experiments on the same metals as are being processed on TEMPEST are planned for the MEL. The flight schedules for the KC-135 experiments are still to be determined in the near future.

  13. Progress in ground-based optical telescopes

    NASA Astrophysics Data System (ADS)

    Énard, Daniel; Maréchal, André; Espiard, Jean

    1996-05-01

    For several decades, the 5 metre Palomar telescope has set a practical limit to the size of ground-based optical telescopes only exceeded by the Russian 6 metre telescope. Using new technologies to produce either large monolithic mirrors or large mosaic of smaller elements, astronomers in Europe, the United States and Japan are developing a new generation of telescopes. Not only are these new telescopes much bigger in size, offering considerably more collecting power, but they also provide a much better angular resolution. To achieve this they rely heavily on computer control techniques and advanced modelling. Even more progress in angular resolution is expected when modern techniques such as adaptive optics and interferometry, which are being implemented on most of the new telescopes, are fully operational. This article evaluates the impact of new technologies on the development of large optical telescopes, in particular on the realization of their optics. The key mirror technologies are reviewed and a particular project, the ESO VLT is reviewed in some more detail as an illustration.

  14. Ground Based Studies of the Outer Planets

    NASA Technical Reports Server (NTRS)

    Trafton, Laurence M.

    2005-01-01

    This report covers progress to date under this grant on our continuing program to conduct ground based studies of the outer solar system planets and satellites, with emphasis on spectroscopy and atmospheric phenomena. The research continues under our new PAST grant, NNG04G131G beginning 5/1/2004. The original period of performance of the subject grant was 3/1/2001 to 2/28/2004, but was extended one year at no cost. Although there is some overlap in the scientific projects conducted during the extended year with those of the new grant, this report is confined to the portion of the work funded under NAG5-10435. The primary goals for this grant period were a comparative study of outer planet thermospheres/ionospheres near solar maximum, extended to the mid-IR, and the investigation of molecular dimers in outer solar system atmospheres. This project supports NASA's planned space missions, Jupiter Polar Orbiter, outer Planet Microprobes, and the recent Cassini flyby of Jupiter. It also supports the OSS strategic plan themes, The Exploration of the Solar System and The Sun-Earth Connection/ Understanding comparative planetary space environments.

  15. Scientific Efficiency of Ground-based Telescopes

    NASA Astrophysics Data System (ADS)

    Abt, Helmut A.

    2012-10-01

    I scanned the six major astronomical journals of 2008 for all 1589 papers that are based on new data obtained from ground-based optical/IR telescopes worldwide. Then I collected data on numbers of papers, citations to them in 3+ years, the most-cited papers, and annual operating costs. These data are assigned to four groups by telescope aperture. For instance, while the papers from telescopes with an aperture >7 m average 1.29 more citations than those with an aperture of 2 to <4 m, this represents a small return for a factor of four difference in operating costs. Among the 17 papers that have received >=100 citations in 3+ years, only half come from the large (>7 m) telescopes. I wonder why the large telescopes do so relatively poorly and suggest possible reasons. I also found that papers based on archival data, such as the Sloan Digital Sky Survey, produce 10.6% as many papers and 20.6% as many citations as those based on new data. Also, the 577.2 papers based on radio data produced 36.3% as many papers and 33.6% as many citations as the 1589 papers based on optical/IR telescopes.

  16. Images and test results of MOSAD all-digital 640 x 480 MWIR prototype camera

    NASA Astrophysics Data System (ADS)

    Mandl, William J.; Shen, Chyau N.; Martin, Phillip

    2000-11-01

    A large format prototype infrared camera based on the MOSAD (Multiplexed OverSample A/D converter) concept was developed and demonstrated. Each pixel readout buffer is composed of a two integrator one bit modulator that converts the accumulating photon induced charge to a digital value. This camera is designed around a 640 X 480 pixel focal plane array with an A/D converter at each pixel. The focal plane is a CMOS design readout hybridized to a MWIR (3 - 5 micron) N on P Mercury Cadmium Telluride detector array with pixels placed on 27 micron centers. Amain developed and tested the readout, camera and electronics. Rockwell Science Center provided the detectors which they hybridized to the Amain readout.

  17. An illustrated heuristic prototype facilitates scientific inventive problem solving: A functional magnetic resonance imaging study.

    PubMed

    Tong, Dandan; Li, Wenfu; Tang, Chaoying; Yang, Wenjing; Tian, Yan; Zhang, Lei; Zhang, Meng; Qiu, Jiang; Liu, Yijun; Zhang, Qinglin

    2015-07-01

    Many scientific inventions (SI) throughout history were inspired by heuristic prototypes (HPs). For instance, an event or piece of knowledge similar to displaced water from a tub inspired Archimedes' principle. However, the neural mechanisms underlying this insightful problem solving are not very clear. Thus, the present study explored the neural correlates used to solve SI problems facilitated by HPs. Each HP had two versions: a literal description with an illustration (LDI) and a literal description with no illustration (LDNI). Thirty-two participants were divided randomly into these two groups. Blood oxygenation level-dependent fMRI contrasts between LDI and LDNI groups were measured. Greater activity in the right middle occipital gyrus (RMOG, BA19), right precentral gyrus (RPCG, BA4), and left middle frontal gyrus (LMFG, BA46) were found within the LDI group as compared to the LDNI group. We discuss these results in terms cognitive functions within these regions related to problem solving and memory retrieval.

  18. Performance of the moving voxel image reconstruction (MVIR) method in the fixed site detection system (FSDS) prototype

    SciTech Connect

    Estep, Robert J.

    2012-05-31

    We have developed a dynamic image reconstruction method called MVIR (Moving Voxel Image Reconstruction) for lane detection in multilane portal monitor systems. MVIR was evaluated for use in the Fixed Site Detection System, a prototype three-lane portal monitor system for EZ-pass toll plazas. As a baseline, we compared MVIR with a static image reconstruction method in analyzing the same real and simulated data sets. Performance was judged by the distributions of image intensities for source and no-source vehicles over many trials as a function of source strength. We found that MVIR produced significantly better results in all cases. The performance difference was greatest at low count rates, where source/no-source distributions were well separated with the MVIR method, allowing reliable source vehicle identification with a low probability of false positive identifications. Static reconstruction of the same data produced overlapping distributions that made source vehicle identification unreliable. The performance of the static method was acceptable at high count rates. Both algorithms reliably identified two strong sources passing through at nearly the same time.

  19. Evaluation of a prototype 3D ultrasound system for multimodality imaging of cervical nodes for adaptive radiation therapy

    NASA Astrophysics Data System (ADS)

    Fraser, Danielle; Fava, Palma; Cury, Fabio; Vuong, Te; Falco, Tony; Verhaegen, Frank

    2007-03-01

    Sonography has good topographic accuracy for superficial lymph node assessment in patients with head and neck cancers. It is therefore an ideal non-invasive tool for precise inter-fraction volumetric analysis of enlarged cervical nodes. In addition, when registered with computed tomography (CT) images, ultrasound information may improve target volume delineation and facilitate image-guided adaptive radiation therapy. A feasibility study was developed to evaluate the use of a prototype ultrasound system capable of three dimensional visualization and multi-modality image fusion for cervical node geometry. A ceiling-mounted optical tracking camera recorded the position and orientation of a transducer in order to synchronize the transducer's position with respect to the room's coordinate system. Tracking systems were installed in both the CT-simulator and radiation therapy treatment rooms. Serial images were collected at the time of treatment planning and at subsequent treatment fractions. Volume reconstruction was performed by generating surfaces around contours. The quality of the spatial reconstruction and semi-automatic segmentation was highly dependent on the system's ability to track the transducer throughout each scan procedure. The ultrasound information provided enhanced soft tissue contrast and facilitated node delineation. Manual segmentation was the preferred method to contour structures due to their sonographic topography.

  20. Medical Image Communication System: Plan, Management And Initial Experience In Prototype At The University Of North Carolina

    NASA Astrophysics Data System (ADS)

    Staab, E. V.; Anderson, D. J.; Chaney, E. L.; Delany, D. J.; DiBianca, F. A.; Guilford, W. B.; Jaques, P. F.; Johnston, R. E.; McCartney, W. H.; Pizer, S. M.; Scatliff, J. H.; Thompson, B. G.; Washburn, D. B.

    1982-01-01

    The revolution in data handling associated with digital systems has excited the medical world into considering replacing existing methods. The integration of digital with analogue video systems into a complete electronic communications network holds tremendous promise. One area where these changes will have significant impact is in medical imaging. The potential of more and better information being,obtained from current studies, more rapid access to studies, intercomparison of images from different modalities, savings in space and equipment, reduced procedure time, improved communication in a distributed department, remote image consultation, and timely data base for management are only some of the advantages that can accrue from proper use of electronic systems. In the hospital, the traditional radiology department is becoming a medical imaging de-partment. To effect a change from the ubiquitous silver halide film base system into a more electronic department will necessitate much experimentation. At the University of North Carolina we are attempting to involve the entire department in these endeavors as well as others such as biomedical engineering, computer science and traditional clinical areas. To facilitate this, a management system has been developed and is being used. The system, our architectural draft of a future department and the initial problems and questions which have arisen from implementing a prototype system will be the subject of this report.

  1. Development of high quantum efficiency, flat panel, thick detectors for megavoltage x-ray imaging: an experimental study of a single-pixel prototype.

    PubMed

    Mei, X; Pang, G

    2005-11-01

    Our overall goal is to develop a new generation of electronic portal imaging devices (EPIDs) with a quantum efficiency (QE) more than an order of magnitude higher and a spatial resolution equivalent to that of EPIDs currently used for portal imaging. A novel design of such a high QE flat-panel based EPID was introduced recently and its feasibility was investigated theoretically [see Pang and Rowlands, Med. Phys. 31, 3004 (2004)]. In this work, we constructed a prototype single-pixel detector based on the novel design. Some fundamental imaging properties including the QE, spatial resolution, and sensitivity of the prototype detector were measured with a 6 MV beam. It has been shown that the experimental results agree well with theoretical predictions and further development based on the novel design including the construction of a prototype area detector is warranted.

  2. Rapid prototyping of multichannel microfluidic devices for single-molecule DNA curtain imaging.

    PubMed

    Robison, Aaron D; Finkelstein, Ilya J

    2014-05-06

    Single-molecule imaging and manipulation of biochemical reactions continues to reveal numerous biological insights. To facilitate these studies, we have developed and implemented a high-throughput approach to organize and image hundreds of individual DNA molecules at aligned diffusion barriers. Nonetheless, obtaining statistically relevant data sets under a variety of reaction conditions remains challenging. Here, we present a method for integrating high-throughput single-molecule "DNA curtain" imaging with poly(dimethylsiloxane) (PDMS)-based microfluidics. Our benchtop fabrication method can be accomplished in minutes with common tools found in all molecular biology laboratories. We demonstrate the utility of this approach by simultaneous imaging of two independent biochemical reaction conditions in a laminar flow device. In addition, five different reaction conditions can be observed concurrently in a passive linear gradient generator. Combining rapid microfluidic fabrication with high-throughput DNA curtains greatly expands our capability to interrogate complex biological reactions.

  3. A Fieldable-Prototype Large-Area Gamma-ray Imager for Orphan Source Search

    SciTech Connect

    Ziock, Klaus-Peter; Fabris, Lorenzo; Carr, Dennis; Collins, Jeff; Cunningham, Mark F; Habte Ghebretatios, Frezghi; Karnowski, Thomas Paul; Marchant, William

    2008-01-01

    We have constructed a unique instrument for use in the search for orphan sources. The system uses gamma-ray imaging to "see through" the natural background variations that effectively limit the search range of normal devices to ~10 m. The imager is mounted in a 4.9- m-long trailer and can be towed by a large personal vehicle. Source locations are determined both in range and along the direction of travel as the vehicle moves. A fully inertial platform coupled to a Global Positioning System receiver is used to map the gamma-ray images onto overhead geospatial imagery. The resulting images provide precise source locations, allowing rapid follow-up work. The instrument simultaneously searches both sides of the street to a distance of 50 m (100-m swath) for milliCurieclass sources with near-perfect performance.

  4. Multichannel Optical Aperture Synthesis Imaging of zeta1 URSAE Majoris with the Navy Prototype Optical Interferometer

    DTIC Science & Technology

    1997-09-01

    Optical Interferometer (NPOI) to obtain the first multichannel optical aperture synthesis images of a star . We observed the spectroscopic binary ~1...interferom- etry had the potential of measuring the exceedingly small angular diameters of stars (Michelson & Pease 1921). Mich- elson also realized that...could be used to image stellar surfaces. The use of interfer- ometry to measure orbits of binary stars also began early in this century (Anderson

  5. Radiologist Evaluation of an X-ray Tube Based Diffraction Enhanced Imaging Prototype Using Full Thickness Breast Specimens.

    SciTech Connect

    Faulconer, L.; Zhong, Z.; Parham, C.; Connor, D. M.; , Kim, E.; Zeng, D.; Livasy, C.; Cole, E.; Kuzmiak, C.; Koomen, M.; Pavic, D.; Pisano, E.

    2009-05-21

    Conventional mammographic image contrast is derived from x-ray absorption, resulting in breast structure visualization due to density gradients that attenuate radiation without distinction between transmitted, scattered, or refracted x-rays. Diffraction-enhanced imaging (DEI) allows for increased contrast with decreased radiation dose compared to conventional mammographic imaging because of monochromatic x-rays, its unique refraction-based contrast mechanism, and excellent scatter rejection. However, a lingering drawback to the clinical translation of DEI has been the requirement for synchrotron radiation. The authors laboratory developed a DEI prototype (DEI-PR) using a readily available tungsten x-ray tube source and traditional DEI crystal optics, providing soft tissue images at 60 keV. Images of full-thickness human breast tissue specimens were acquired on synchrotron-based DEI (DEI-SR), DEI-PR, and digital mammographic systems. A panel of expert radiologists evaluated lesion feature visibility and correlation with pathology after receiving training on the interpretation of refraction contrast mammographic images. For mammographic features (mass, calcification), no significant differences were detected between the DEI-SR and DEI-PR systems. Benign lesions were perceived as better seen by radiologists using the DEI-SR system than the DEI-PR system at the [111] reflectivity, with generalizations limited by small sample size. No significant differences between DEI-SR and DEI-PR were detected for any other lesion type (atypical, cancer) at either crystal reflectivity. Thus, except for benign lesion characterizations, the DEI-PR system's performance was roughly equivalent to that of the traditional DEI system, demonstrating a significant step toward clinical translation of this modality for breast cancer applications.

  6. Carbon-fiber-reinforced polymer variable-curvature mirror used for optical zoom imaging: prototype design and experimental demonstration

    NASA Astrophysics Data System (ADS)

    Zhao, Hui; Fan, Xuewu; Pang, Zhihai; Ren, Guorui; Wang, Wei; Xie, Yongjie; Ma, Zhen; Du, Yunfei; Su, Yu; Wei, Jingxuan

    2015-02-01

    In recent years, optical zoom imaging without moving elements has received much attention. The key to realizing this technique lies in the design of the variable-curvature mirror (VCM). To obtain enough optical magnification, the VCM should be able to change its radius of curvature over a wide range. In other words, the VCM must be able to provide a large sagittal variation, which requires the mirror material to be robust during curvature variation, require little force to deform, and have high ultimate strength. Carbon-fiber-reinforced polymer (CFRP) satisfies all these requirements and is suitable for fabricating such a VCM. Therefore, in this research, a CFRP prototype VCM has been designed, fabricated, and tested. With a diameter of 100 mm, a thickness of 2 mm, and an initial radius of curvature of 1740 mm, this VCM can provide a maximum 23-μm sagittal variation and a minimum and maximum radius of curvature of 1705 and 1760 mm.

  7. Usability and eHealth Literacy Evaluation of a Mobile Health Application Prototype to Track Diagnostic Imaging Examinations.

    PubMed

    Griffith, Janessa; Monkman, Helen

    2017-01-01

    In the absence of a pan-Canadian electronic health record, unnecessary duplicate diagnostic imaging (DI) examinations are sometimes ordered when a physician is not aware of prior DI or prior DI is not available. Research suggests that physicians may ask their patient to recall their DI history; however, patient recall of DI can be unreliable. As a potential solution, a patient-facing mobile health application (app) prototype was developed for users to record their DI. The app was designed to be usable and inclusive to users of all health literacy levels. The aim of this paper is to demonstrate how eHealth literacy and usability heuristics can be used during the design phases of app development.

  8. Monitoring Surface Deformation using Polarimetric Ground Based Interferometric Radar

    NASA Astrophysics Data System (ADS)

    Legarsky, J. J.; Gomez, F.; Rosenblad, B.; Loehr, E.; Cherukumilli, S.; Deng, H.; Held, B.; Jenkins, W.

    2012-12-01

    Surface deformation monitoring using ground based interferometric radar (GBIR) measurements may be desirable for a number of applications in the earth sciences. The University of Missouri (MU) research team has ongoing efforts to use the MU GBIR for monitoring surface deformation at a number of sites. Measurements have been collected at sites requiring access by various transportation means such as using off-road vehicle, hiking, and helicopter. Once on site, initial setup takes about 10 minutes. After setup, an image may be acquired by azimuth scan about every 20 seconds. The highly portable system lends itself to rapid deployment in remote environments and repeat survey sites. The MU GBIR's high portability and fast imaging capabilities allow rapid surveying and long-term surveying potential of surface deformation. Imagery may be formed in near real time for initial quick looks. After data collection, imagery data may be further enhanced by radiometric calibration, polarimetric calibration, and time-series analysis. Imaging may be acquired at the electromagnetic spectral bands of C-band and Ku-band. Prior demonstration of millimeter and better sensitivity to deformation over the course of a day of data collects has been performed using the MU GBIR. In addition, the MU GBIR can be removed and re-positioned at the same point with geodetic-grade precision for repeat surveys. Study results and additional development progress will be presented. This project is sponsored by a grant from the National Science Foundation.

  9. Tests of a Compton imaging prototype in a monoenergetic 4.44 MeV photon field—a benchmark setup for prompt gamma-ray imaging devices

    NASA Astrophysics Data System (ADS)

    Golnik, C.; Bemmerer, D.; Enghardt, W.; Fiedler, F.; Hueso-González, F.; Pausch, G.; Römer, K.; Rohling, H.; Schöne, S.; Wagner, L.; Kormoll, T.

    2016-06-01

    The finite range of a proton beam in tissue opens new vistas for the delivery of a highly conformal dose distribution in radiotherapy. However, the actual particle range, and therefore the accurate dose deposition, is sensitive to the tissue composition in the proton path. Range uncertainties, resulting from limited knowledge of this tissue composition or positioning errors, are accounted for in the form of safety margins. Thus, the unverified particle range constrains the principle benefit of proton therapy. Detecting prompt γ-rays, a side product of proton-tissue interaction, aims at an on-line and non-invasive monitoring of the particle range, and therefore towards exploiting the potential of proton therapy. Compton imaging of the spatial prompt γ-ray emission is a promising measurement approach. Prompt γ-rays exhibit emission energies of several MeV. Hence, common radioactive sources cannot provide the energy range a prompt γ-ray imaging device must be designed for. In this work a benchmark measurement-setup for the production of a localized, monoenergetic 4.44 MeV γ-ray source is introduced. At the Tandetron accelerator at the HZDR, the proton-capture resonance reaction 15N(p,α γ4.439)12C is utilized. This reaction provides the same nuclear de-excitation (and γ-ray emission) occurrent as an intense prompt γ-ray line in proton therapy. The emission yield is quantitatively described. A two-stage Compton imaging device, dedicated for prompt γ-ray imaging, is tested at the setup exemplarily. Besides successful imaging tests, the detection efficiency of the prototype at 4.44 MeV is derived from the measured data. Combining this efficiency with the emission yield for prompt γ-rays, the number of valid Compton events, induced by γ-rays in the energy region around 4.44 MeV, is estimated for the prototype being implemented in a therapeutic treatment scenario. As a consequence, the detection efficiency turns out to be a key parameter for prompt

  10. Projection x-ray imaging with photon energy weighting: experimental evaluation with a prototype detector.

    PubMed

    Shikhaliev, Polad M

    2009-08-21

    The signal-to-noise ratio (SNR) in x-ray imaging can be increased using a photon counting detector which could allow for rejecting electronics noise and for weighting x-ray photons according to their energies. This approach, however, was not feasible for a long time because photon counting x-ray detectors with very high count rates, good energy resolution and a large number of small pixels were required. These problems have been addressed with the advent of new detector materials, fast readout electronics and powerful computers. In this work, we report on the experimental evaluation of projection x-ray imaging with a photon counting cadmium-zinc-telluride (CZT) detector with energy resolving capabilities. The detector included two rows of pixels with 128 pixels per row with 0.9 x 0.9 mm(2) pixel size, and a 2 Mcount pixel(-1) s(-1) count rate. The x-ray tube operated at 120 kVp tube voltage with 2 mm Al-equivalent inherent filtration. The x-ray spectrum was split into five regions, and five independent x-ray images were acquired at a time. These five quasi-monochromatic x-ray images were used for x-ray energy weighting and material decomposition. A tissue-equivalent phantom was used including contrast elements simulating adipose, calcifications, iodine and air. X-ray energy weighting improved the SNR of calcifications and iodine by a factor of 1.32 and 1.36, respectively, as compared to charge integrating. Material decomposition was performed by dual energy subtraction. The low- and high-energy images were generated in the energy ranges of 25-60 keV and 60-120 keV, respectively, by combining five monochromatic image data into two. X-ray energy weighting was applied to low- and high-energy images prior to subtraction, and this improved the SNR of calcifications and iodine in dual energy subtracted images by a factor of 1.34 and 1.25, respectively, as compared to charge integrating. The detector energy resolution, spatial resolution, linearity, count rate, noise and

  11. Projection x-ray imaging with photon energy weighting: experimental evaluation with a prototype detector

    NASA Astrophysics Data System (ADS)

    Shikhaliev, Polad M.

    2009-08-01

    The signal-to-noise ratio (SNR) in x-ray imaging can be increased using a photon counting detector which could allow for rejecting electronics noise and for weighting x-ray photons according to their energies. This approach, however, was not feasible for a long time because photon counting x-ray detectors with very high count rates, good energy resolution and a large number of small pixels were required. These problems have been addressed with the advent of new detector materials, fast readout electronics and powerful computers. In this work, we report on the experimental evaluation of projection x-ray imaging with a photon counting cadmium-zinc-telluride (CZT) detector with energy resolving capabilities. The detector included two rows of pixels with 128 pixels per row with 0.9 × 0.9 mm2 pixel size, and a 2 Mcount pixel-1 s-1 count rate. The x-ray tube operated at 120 kVp tube voltage with 2 mm Al-equivalent inherent filtration. The x-ray spectrum was split into five regions, and five independent x-ray images were acquired at a time. These five quasi-monochromatic x-ray images were used for x-ray energy weighting and material decomposition. A tissue-equivalent phantom was used including contrast elements simulating adipose, calcifications, iodine and air. X-ray energy weighting improved the SNR of calcifications and iodine by a factor of 1.32 and 1.36, respectively, as compared to charge integrating. Material decomposition was performed by dual energy subtraction. The low- and high-energy images were generated in the energy ranges of 25-60 keV and 60-120 keV, respectively, by combining five monochromatic image data into two. X-ray energy weighting was applied to low- and high-energy images prior to subtraction, and this improved the SNR of calcifications and iodine in dual energy subtracted images by a factor of 1.34 and 1.25, respectively, as compared to charge integrating. The detector energy resolution, spatial resolution, linearity, count rate, noise and image

  12. Improved OCT imaging of lung tissue using a prototype for total liquid ventilation

    NASA Astrophysics Data System (ADS)

    Schnabel, Christian; Meissner, Sven; Koch, Edmund

    2011-06-01

    Optical coherence tomography (OCT) is used for imaging subpleural alveoli in animal models to gain information about dynamic and morphological changes of lung tissue during mechanical ventilation. The quality of OCT images can be increased if the refraction index inside the alveoli is matched to the one of tissue via liquid-filling. Thereby, scattering loss can be decreased and higher penetration depth and tissue contrast can be achieved. Until now, images of liquid-filled lungs were acquired in isolated and fixated lungs only, so that an in vivo measurement situation is not present. To use the advantages of liquid-filling for in vivo imaging of small rodent lungs, it was necessary to develop a liquid ventilator. Perfluorodecalin, a perfluorocarbon, was selected as breathing fluid because of its refraction index being similar to the one of water and the high transport capacity for carbon dioxide and oxygen. The setup is characterized by two independent syringe pumps to insert and withdraw the fluid into and from the lung and a custom-made control program for volume- or pressure-controlled ventilation modes. The presented results demonstrate the liquid-filling verified by optical coherence tomography and intravital microscopy (IVM) and the advantages of liquid-filling to OCT imaging of subpleural alveoli.

  13. A prototype manipulator for magnetic resonance-guided interventions inside standard cylindrical magnetic resonance imaging scanners.

    PubMed

    Tsekos, Nikolaos V; Ozcan, Alpay; Christoforou, Eftychios

    2005-11-01

    The aim of this work is to develop a remotely controlled manipulator to perform minimally invasive diagnostic and therapeutic interventions in the abdominal and thoracic cavities, with real-time magnetic resonance imaging (MRI) guidance inside clinical cylindrical MR scanners. The manipulator is composed of a three degree of freedom Cartesian motion system, which resides outside the gantry of the scanner, and serves as the holder and global positioner of a three degree of freedom arm which extends inside the gantry of the scanner At its distal end, the arm's end-effector can carry an interventional tool such as a biopsy needle, which can be advanced to a desired depth by means of a seventh degree of freedom. These seven degrees of freedom, provided by the entire assembly, offer extended manipulability to the device and a wide envelope of operation to the user, who can select a trajectory suitable for the procedure. The device is constructed of nonmagnetic and nonconductive fiberglass, and carbon fiber composite materials, to minimize artifacts and distortion on the MR images as well as eliminate effects on its operation from the high magnetic field and the fast switching magnetic field gradients used in MR imaging. A user interface was developed for man-in-the-loop control of the device using real-time MR images. The user interface fuses all sensor signals (MR and manipulator information) in a visualization, planning, and control command environment. Path planning is performed with graphical tools for setting the trajectory of insertion of the interventional tool using multislice and/or three dimensional MR images which are refreshed in real time. The device control is performed with an embedded computer which runs real-time control software. The manipulator compatibility with the MR environment and image-guided operation was tested on a 1.5 T MR scanner.

  14. A rapid prototyping methodology to implement and optimize image processing algorithms for FPGAs

    NASA Astrophysics Data System (ADS)

    Akil, Mohamed; Niang, Pierre; Grandpierre, Thierry

    2006-02-01

    In this article we present the local operations in image processing based upon spatial 2D discrete convolution. We study different implementation of such local operations. We also present the principles and the design flow of the AAA methodology and its associated CAD software tool for integrated circuit (SynDEx-IC). In this methodology, the algorithm is modeled by Conditioned (if - then - else) and Factorized (Loop) Data Dependence Graph and the optimized implementation is obtained by graph transformations. The AAA/SynDEx-IC is used to specify and to optimize the some digital image filters on FPGA XC2100 board.

  15. Determination of the detective quantum efficiency of a prototype, megavoltage indirect detection, active matrix flat-panel imager.

    PubMed

    El-Mohri, Y; Jee, K W; Antonuk, L E; Maolinbay, M; Zhao, Q

    2001-12-01

    After years of aggressive development, active matrix flat-panel imagers (AMFPIs) have recently become commercially available for radiotherapy imaging. In this paper we report on a comprehensive evaluation of the signal and noise performance of a large-area prototype AMFPI specifically developed for this application. The imager is based on an array of 512 x 512 pixels incorporating amorphous silicon photodiodes and thin-film transistors offering a 26 x 26 cm2 active area at a pixel pitch of 508 microm. This indirect detection array was coupled to various x-ray converters consisting of a commercial phosphor screen (Lanex Fast B, Lanex Regular, or Lanex Fine) and a 1 mm thick copper plate. Performance of the imager in terms of measured sensitivity, modulation transfer function (MTF), noise power spectra (NPS), and detective quantum efficiency (DQE) is reported at beam energies of 6 and 15 MV and at doses of 1 and 2 monitor units (MU). In addition, calculations of system performance (NPS, DQE) based on cascaded-system formalism were reported and compared to empirical results. In these calculations, the Swank factor and spatial energy distributions of secondary electrons within the converter were modeled by means of EGS4 Monte Carlo simulations. Measured MTFs of the system show a weak dependence on screen type (i.e., thickness), which is partially due to the spreading of secondary radiation. Measured DQE was found to be independent of dose for the Fast B screen, implying that the imager is input-quantum-limited at 1 MU, even at an extended source-to-detector distance of 200 cm. The maximum DQE obtained is around 1%--a limit imposed by the low detection efficiency of the converter. For thinner phosphor screens, the DQE is lower due to their lower detection efficiencies. Finally, for the Fast B screen, good agreement between calculated and measured DQE was observed.

  16. GIFTS EDU Ground-based Measurement Experiment

    NASA Technical Reports Server (NTRS)

    Zhou, Daniel K.; Smith, W. L., Sr.; Zollinger, L. J.; Huppi, R. J.; Reisse, R. A.; Larar, A. M.; Liu, X.; Tansock, J. J., Jr.; Jensen, S. M.; Revercomb, H. E.; hide

    2007-01-01

    Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) Engineering Demonstration Unit (EDU) is an imaging infrared spectrometer designed for atmospheric soundings. The EDU groundbased measurement experiment was held in Logan, Utah during September 2006 to demonstrate its extensive capabilities for geosynchronous and other applications.

  17. Science Highlights and Future Plans of Ground-based Optical/infrared Interferometry

    NASA Astrophysics Data System (ADS)

    Akeson, Rachel L.; Armstrong, J. T.; Creech-Eakman, M.; Hinz, P.; Hutter, D.; McAlister, H.; Ragland, S.; Ridgway, S.; ten Brummelaar, T.; Townes, C.; Wizinowich, P.

    2009-05-01

    Ground-based optical/infrared long-baseline interferometry continues to extend its capabilities in the U.S., where several existing facilities demonstrate its unique capabilities in a broad range of scientific applications. This poster presents brief overviews of the CHARA Array and the Infrared Spatial Interferometer (ISI) on Mt. Wilson, CA; the Navy Prototype Optical Interferometer (NPOI) on Anderson Mesa near Flagstaff, AZ; and the Keck Interferometer (KI) on Mauna Kea, HI; as well as under-construction facilities; the Magdalena Ridge Observatory Interferometer (MROI) in the Magdalena Mountains of New Mexico and the Large Binocular Telescope Interferometer (LBTI) on Mt. Graham, Arizona. Also included are pointers to a sample of the scientific results from U.S. interferometers and to data archives. Recent scientific highlights range from stellar atmospheres (precise diameters, including G/K dwarfs; limb darkening; Cepheid pulsations) to circumstellar material (water detected in a protoplanetary disk; debris disks; Be star disks; warped circumbinary disks; dust shells) to orbits and stellar masses in double, triple, and quadruple systems, to images of stellar surfaces. While the great majority of results to date have focused on stellar astrophysics, the MROI strives to have sensitivity sufficient to access a statistical sample of AGN. We have recently formed a consortium and are proposing to open all our facilities to the broader astronomical community via an opportunity called MOISAIC (Milliarcsecond Optical/Infrared Science: Access to Interferometry for the Community). Research with these independently operated facilities is sponsored by the Oceanographer of the Navy and the Office of Naval Research for NPOI; the National Aeronautics and Space Administration for KI and LBTI; the National Science Foundation and Georgia State University for the CHARA Array; and the Office of Naval Research, the National Science Foundation, and the Gordon and Betty Moore Foundation

  18. Image Analysis via Soft Computing: Prototype Applications at NASA KSC and Product Commercialization

    NASA Technical Reports Server (NTRS)

    Dominguez, Jesus A.; Klinko, Steve

    2011-01-01

    This slide presentation reviews the use of "soft computing" which differs from "hard computing" in that it is more tolerant of imprecision, partial truth, uncertainty, and approximation and its use in image analysis. Soft computing provides flexible information processing to handle real life ambiguous situations and achieve tractability, robustness low solution cost, and a closer resemblance to human decision making. Several systems are or have been developed: Fuzzy Reasoning Edge Detection (FRED), Fuzzy Reasoning Adaptive Thresholding (FRAT), Image enhancement techniques, and visual/pattern recognition. These systems are compared with examples that show the effectiveness of each. NASA applications that are reviewed are: Real-Time (RT) Anomaly Detection, Real-Time (RT) Moving Debris Detection and the Columbia Investigation. The RT anomaly detection reviewed the case of a damaged cable for the emergency egress system. The use of these techniques is further illustrated in the Columbia investigation with the location and detection of Foam debris. There are several applications in commercial usage: image enhancement, human screening and privacy protection, visual inspection, 3D heart visualization, tumor detections and x ray image enhancement.

  19. VISDTA: A video imaging system for detection, tracking, and assessment: Prototype development and concept demonstration

    SciTech Connect

    Pritchard, D.A.

    1987-05-01

    It has been demonstrated that thermal imagers are an effective surveillance and assessment tool for security applications because: (1) they work day or night due to their sensitivity to thermal signatures; (2) penetrability through fog, rain, dust, etc., is better than human eyes; (3) short or long range operation is possible with various optics; and (4) they are strictly passive devices providing visible imagery which is readily interpreted by the operator with little training. Unfortunately, most thermal imagers also require the setup of a tripod, connection of batteries, cables, display, etc. When this is accomplished, the operator must manually move the camera back and forth searching for signs of aggressor activity. VISDTA is designed to provide automatic panning, and in a sense, ''watch'' the imagery in place of the operator. The idea behind the development of VISDTA is to provide a small, portable, rugged system to automatically scan areas and detect targets by computer processing of images. It would use a thermal imager and possibly an intensified day/night TV camera, a pan/ tilt mount, and a computer for system control. If mounted on a dedicated vehicle or on a tower, VISDTA will perform video motion detection functions on incoming video imagery, and automatically scan predefined patterns in search of abnormal conditions which may indicate attempted intrusions into the field-of-regard. In that respect, VISDTA is capable of improving the ability of security forces to maintain security of a given area of interest by augmenting present techniques and reducing operator fatigue.

  20. Uses and Values of Prototypic Visual Images in High School Mathematics.

    ERIC Educational Resources Information Center

    Presmeg, Norma C.

    Imagery use in high school mathematics classrooms was studied. A visual image was defined as a mental scheme depicting visual or spatial information, but this definition was not spelled out to teachers or students, in order to learn what they meant by the concept. Subjects were 13 high school teachers and 54 of their students interviewed over 3…

  1. COINSTAC: A Privacy Enabled Model and Prototype for Leveraging and Processing Decentralized Brain Imaging Data

    PubMed Central

    Plis, Sergey M.; Sarwate, Anand D.; Wood, Dylan; Dieringer, Christopher; Landis, Drew; Reed, Cory; Panta, Sandeep R.; Turner, Jessica A.; Shoemaker, Jody M.; Carter, Kim W.; Thompson, Paul; Hutchison, Kent; Calhoun, Vince D.

    2016-01-01

    The field of neuroimaging has embraced the need for sharing and collaboration. Data sharing mandates from public funding agencies and major journal publishers have spurred the development of data repositories and neuroinformatics consortia. However, efficient and effective data sharing still faces several hurdles. For example, open data sharing is on the rise but is not suitable for sensitive data that are not easily shared, such as genetics. Current approaches can be cumbersome (such as negotiating multiple data sharing agreements). There are also significant data transfer, organization and computational challenges. Centralized repositories only partially address the issues. We propose a dynamic, decentralized platform for large scale analyses called the Collaborative Informatics and Neuroimaging Suite Toolkit for Anonymous Computation (COINSTAC). The COINSTAC solution can include data missing from central repositories, allows pooling of both open and “closed” repositories by developing privacy-preserving versions of widely-used algorithms, and incorporates the tools within an easy-to-use platform enabling distributed computation. We present an initial prototype system which we demonstrate on two multi-site data sets, without aggregating the data. In addition, by iterating across sites, the COINSTAC model enables meta-analytic solutions to converge to “pooled-data” solutions (i.e., as if the entire data were in hand). More advanced approaches such as feature generation, matrix factorization models, and preprocessing can be incorporated into such a model. In sum, COINSTAC enables access to the many currently unavailable data sets, a user friendly privacy enabled interface for decentralized analysis, and a powerful solution that complements existing data sharing solutions. PMID:27594820

  2. Simultaneous acquisition of magnetic resonance spectroscopy (MRS) data and positron emission tomography (PET) images with a prototype MR-compatible, small animal PET imager

    NASA Astrophysics Data System (ADS)

    Raylman, Raymond R.; Majewski, Stan; Velan, S. Sendhil; Lemieux, Susan; Kross, Brian; Popov, Vladimir; Smith, Mark F.; Weisenberger, Andrew G.

    2007-06-01

    Multi-modality imaging (such as PET-CT) is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET, fused with anatomical images created by MRI, allow the correlation of form with function. Perhaps more exciting than the combination of anatomical MRI with PET, is the melding of PET with MR spectroscopy (MRS). Thus, two aspects of physiology could be combined in novel ways to produce new insights into the physiology of normal and pathological processes. Our team is developing a system to acquire MRI images and MRS spectra, and PET images contemporaneously. The prototype MR-compatible PET system consists of two opposed detector heads (appropriate in size for small animal imaging), operating in coincidence mode with an active field-of-view of ˜14 cm in diameter. Each detector consists of an array of LSO detector elements coupled through a 2-m long fiber optic light guide to a single position-sensitive photomultiplier tube. The use of light guides allows these magnetic field-sensitive elements of the PET imager to be positioned outside the strong magnetic field of our 3T MRI scanner. The PET scanner imager was integrated with a 12-cm diameter, 12-leg custom, birdcage coil. Simultaneous MRS spectra and PET images were successfully acquired from a multi-modality phantom consisting of a sphere filled with 17 brain relevant substances and a positron-emitting radionuclide. There were no significant changes in MRI or PET scanner performance when both were present in the MRI magnet bore. This successful initial test demonstrates the potential for using such a multi-modality to obtain complementary MRS and PET data.

  3. Enhancements to and Characterization of the Very Early Time Electromagnetic (VETEM) Prototype Instrument and Applications to Shallow Subsurface Imaging at Sites in the DOE Complex - Final Report

    SciTech Connect

    Wright, D.L.; Chew, W.C.

    2000-12-01

    Field tests and deployments of VETEM is a flexible and highly effective new system for electromagnetic imaging that offers significant new 3D electromagnetic imaging capabilities in the shallow subsurface. Important new numerical modeling techniques have been produced, which are applicable to electromagnetic subsurface imaging, and suggest further research and development. In addition, this research has also produced a flexible, fast, and fully functional prototype VETEM system that has produced some remarkable subsurface images, has bridged the gap between pure research and applications, and is now available for use at DOE sites that have shallow subsurface imaging needs.

  4. Effect of recombination in a high quantum efficiency prototype ionization-chamber-based electronic portal imaging device.

    PubMed

    Gopal, A; Samant, S S

    2007-08-01

    The quantum efficiency (QE) of an imaging detector can be increased by utilizing a thick, high-density detection medium to increase the number of quantum interactions. However, image quality is more accurately described by the detection quantum efficiency (DQE). If a significant fraction of the increase in the number of detected quanta from a thick, dense detector were to result in useful imaging signal, this represents a favorable case where enhanced QE leads to increased DQE. However, for ionization-type detectors, one factor that limits DQE is the recombination between ion pairs that acts as a secondary quantum sink due to which enhancement in QE may not result in higher DQE depending on the extent of the signal loss from recombination. Therefore, an analysis of signal loss mechanisms or quantum sinks in an imaging system is essential for validating the overall benefit of high QE detectors. In this paper, a study of ion recombination as a secondary quantum sink is presented for a high QE prototype ion-chamber-based electronic portal imaging device (EPID): the kinestatic charge detector (KCD). The KCD utilizes a high pressure noble gas (krypton or xenon at 100 atm) and an arbitrarily large detector thickness (of the order of centimeters), resulting in a high QE imager. Compared with commercial amorphous silicon flat panel imagers that provide DQE(0) approximately 0.01, the KCD has much higher DQE. Studies indicated that DQE(0) = 0.20 for 6.1 cm thick, 100 atm (rho = 3.4 g/cm3) xenon chamber, and DQE(0)=0.34 for a 9.1 cm thick chamber. A series of experiments was devised and conducted to determine the signal loss due to recombination for a KCD chamber. The measurements indicated a fractional recombination loss of about 14% for a krypton chamber and about 18% for a xenon chamber under standard operating conditions (100 atm chamber pressure and 1275 V/cm electric field intensity). A theoretical treatment of the effect of recombination on imaging signal

  5. Prototype development of a Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR)

    NASA Technical Reports Server (NTRS)

    Kangaslahti, Pekka; Tanner, Alan; Wilson, William; Dinardo, Steve; Lambrigsten, Bjorn

    2005-01-01

    Weather prediction and hurricane tracking would greatly benefit of a continuous imaging capability of a hemisphere at millimeter wave frequencies. We are developing a synthetic thinned aperture radiometer (STAR) prototype operating from 50 to 56 GHz as a ground-based testbed to demonstrate the technologies needed to do full earth disk atmospheric temperature soundings from Geostationary orbit with very high spatial resolution. The prototype consists of a Y-array of 24 MMIC receivers that are compact units implemented with low noise InP MMIC LNAs, second harmonic I-Q mixers, low power IF amplifiers and include internal digital bias control with serial line communication to enable low cost testing and system integration. Furthermore, this prototype STAR includes independent LO and noise calibration signal phase switching circuitry for each arm of the Y-array to verify the operation and calibration of the system.

  6. Prototype of Partial Cutting Tool of Geological Map Images Distributed by Geological Web Map Service

    NASA Astrophysics Data System (ADS)

    Nonogaki, S.; Nemoto, T.

    2014-12-01

    Geological maps and topographical maps play an important role in disaster assessment, resource management, and environmental preservation. These map information have been distributed in accordance with Web services standards such as Web Map Service (WMS) and Web Map Tile Service (WMTS) recently. In this study, a partial cutting tool of geological map images distributed by geological WMTS was implemented with Free and Open Source Software. The tool mainly consists of two functions: display function and cutting function. The former function was implemented using OpenLayers. The latter function was implemented using Geospatial Data Abstraction Library (GDAL). All other small functions were implemented by PHP and Python. As a result, this tool allows not only displaying WMTS layer on web browser but also generating a geological map image of intended area and zoom level. At this moment, available WTMS layers are limited to the ones distributed by WMTS for the Seamless Digital Geological Map of Japan. The geological map image can be saved as GeoTIFF format and WebGL format. GeoTIFF is one of the georeferenced raster formats that is available in many kinds of Geographical Information System. WebGL is useful for confirming a relationship between geology and geography in 3D. In conclusion, the partial cutting tool developed in this study would contribute to create better conditions for promoting utilization of geological information. Future work is to increase the number of available WMTS layers and the types of output file format.

  7. Imaging characteristics of distance-driven method in a prototype cone-beam computed tomography (CBCT)

    NASA Astrophysics Data System (ADS)

    Choi, Sunghoon; Kim, Ye-seul; Lee, Haenghwa; Lee, Donghoon; Seo, Chang-Woo; Kim, Hee-Joung

    2016-03-01

    Cone-beam computed tomography (CBCT) has widely been used and studied in both medical imaging and radiation therapy. The aim of this study was to evaluate our newly developed CBCT system by implementing a distance-driven system modeling technique in order to produce excellent and accurate cross-sectional images. For the purpose of comparing the performance of the distance-driven methods, we also performed pixel-driven and ray-driven techniques when conducting forward- and back-projection schemes. We conducted the Feldkamp-Davis-Kress (FDK) algorithm and simultaneous algebraic reconstruction technique (SART) to retrieve a volumetric information of scanned chest phantom. The results indicated that contrast-to-noise (CNR) of the reconstructed images by using FDK and SART showed 8.02 and 15.78 for distance-driven, whereas 4.02 and 5.16 for pixel-driven scheme and 7.81 and 13.01 for ray-driven scheme, respectively. This could demonstrate that distance-driven method described more closely the chest phantom compared to pixel- and ray-driven. However, both elapsed time for modeling a system matrix and reconstruction time took longer time when performing the distance-driven scheme. Therefore, future works will be directed toward reducing computational time to acceptable limits for real applications.

  8. Gaussian total variation blind restoration of ground-based space object imagery

    NASA Astrophysics Data System (ADS)

    Guo, Shiping; Zhang, Rongzhi; Xu, Rong; Liu, Changhai; Li, Jisheng

    2016-11-01

    We focus on the restoration of ground-based space object adaptive optics (AO) images distorted by atmospheric turbulence. A total variation (TV) blind AO images restoration method taking advantage of low-order Gaussian derivative operators is presented. Unlike previous definition of the TV regularization term, we propose to define the TV prior by the Gaussian gradient operators instead of the general finite-difference gradient operators. Specifically, in each iterative step of alternating minimization when solving the TV blind deconvolution problem, the first-order Gaussian derivative operator (i.e. gradient magnitude of Gaussian) is used to construct the total variation norm of object image, and the secondorder Gaussian derivative operator (i.e. Laplacian of Gaussian) is used to spatially adjust the regularization parameter. Comparative simulation experiments show that this simple improvement is much practicable for ground-based space object images and can provide more robust performance on both restoration accuracy and convergence property.

  9. Movable Ground Based Recovery System for Reuseable Space Flight Hardware

    NASA Technical Reports Server (NTRS)

    Sarver, George L. (Inventor)

    2013-01-01

    A reusable space flight launch system is configured to eliminate complex descent and landing systems from the space flight hardware and move them to maneuverable ground based systems. Precision landing of the reusable space flight hardware is enabled using a simple, light weight aerodynamic device on board the flight hardware such as a parachute, and one or more translating ground based vehicles such as a hovercraft that include active speed, orientation and directional control. The ground based vehicle maneuvers itself into position beneath the descending flight hardware, matching its speed and direction and captures the flight hardware. The ground based vehicle will contain propulsion, command and GN&C functionality as well as space flight hardware landing cushioning and retaining hardware. The ground based vehicle propulsion system enables longitudinal and transverse maneuverability independent of its physical heading.

  10. Quantitative imaging of the microbubble concentrations by using an in-line phase contrast tomosynthesis prototype: a preliminary phantom study

    NASA Astrophysics Data System (ADS)

    Wu, Di; Ghani, Muhammad U.; Wong, Molly D.; Li, Yuhua; Yang, Kai; Chen, Wei R.; Zheng, Bin; Liu, Hong

    2016-03-01

    The purpose of this study is to demonstrate the feasibility of using a high-energy in-line phase contrast tomosynthesis system to quantitatively imaging microbubbles in a tissue simulating phantom under a limited radiation dose. The imaging system used in the investigation was a bench top in-line phase contrast tomosynthesis prototype operated under 120 kVp tube voltage and 0.5 mA tube current. A prime beam filter made of 2.3 mm Cu, 0.8 mm Pb and 1.0 mm Al was employed to obtain as large as possible portion of x-ray photon energy higher than 60 keV. The tissue simulating phantom was built by three acrylic slabs and a wax slab to mimic a 40 mm thick compressed breast. There were two tiny-sized structures with average 1 mm depth engraved on the two different layers. The microbubble suspensions with different concentrations were injected into those tiny structures. The inline phase contrast angular projections acquired were used to reconstruct the in-plane slices of the tiny structures on different layers. The CNRs vs microbubble concentrations were investigated. As the result, the microbubble suspensions were clearly visible, showing higher CNR when compared with the areas with no microbubble. Furthermore, a monotonously increasing relation between CNRs and microbubble concentrations was observed after calculating the area CNR of the phase contrast tomosynthesis slices.

  11. LOW-FREQUENCY IMAGING OF FIELDS AT HIGH GALACTIC LATITUDE WITH THE MURCHISON WIDEFIELD ARRAY 32 ELEMENT PROTOTYPE

    SciTech Connect

    Williams, Christopher L.; Hewitt, Jacqueline N.; Levine, Alan M.; De Oliveira-Costa, Angelica; Hernquist, Lars L.; Bernardi, Gianni; Bowman, Judd D.; Briggs, Frank H.; Gaensler, B. M.; Mitchell, Daniel A.; Subrahmanyan, Ravi; Sadler, Elaine M.; Morales, Miguel F.; Sethi, Shiv K.; Arcus, Wayne; Crosse, Brian W.; Barnes, David G.; Bunton, John D.; Cappallo, Roger C.; Corey, Brian E.; and others

    2012-08-10

    The Murchison Widefield Array (MWA) is a new low-frequency, wide-field-of-view radio interferometer under development at the Murchison Radio-astronomy Observatory in Western Australia. We have used a 32 element MWA prototype interferometer (MWA-32T) to observe two 50 Degree-Sign diameter fields in the southern sky, covering a total of {approx}2700 deg{sup 2}, in order to evaluate the performance of the MWA-32T, to develop techniques for epoch of reionization experiments, and to make measurements of astronomical foregrounds. We developed a calibration and imaging pipeline for the MWA-32T, and used it to produce {approx}15' angular resolution maps of the two fields in the 110-200 MHz band. We perform a blind source extraction using these confusion-limited images, and detect 655 sources at high significance with an additional 871 lower significance source candidates. We compare these sources with existing low-frequency radio surveys in order to assess the MWA-32T system performance, wide-field analysis algorithms, and catalog quality. Our source catalog is found to agree well with existing low-frequency surveys in these regions of the sky and with statistical distributions of point sources derived from Northern Hemisphere surveys; it represents one of the deepest surveys to date of this sky field in the 110-200 MHz band.

  12. Customized vaginal vault brachytherapy with computed tomography imaging-derived applicator prototyping.

    PubMed

    Wiebe, Ericka; Easton, Harry; Thomas, Gillian; Barbera, Lisa; D'Alimonte, Laura; Ravi, Ananth

    2015-01-01

    A novel customized vaginal brachytherapy mould technique has been developed for clinical use. This image-guided technique provides a brachytherapy applicator solution for irregular vaginal vault configuration and/or a wide vaginal apex relative to the vaginal introitus that would be sub-optimally treated with standard cylinders. The customized vaginal applicator is generated by the following process: CT images are obtained with contrast-soaked vaginal packing in situ to highlight unique anatomical detail. A 3-dimensional digital model is developed from the images and subsequently converted into a custom applicator with the use of stereolithography, which is an additive manufacturing technique whereby layers 50-100 μm thick of resin are deposited and polymerized using a laser to create intricate 3-dimensional objects. The density of the applicator and the dose delivered using the custom applicator were both measured to ensure accurate dosimetry. The CT-based densities of a clinical vaginal cylinder and the cylinder generated using stereolithography were 1.29 ± 0.06 g/cm(3) vs 1.28 ± 0.01 g/cm(3), respectively. The mean measured dose from a representative stereolithographed applicator normalized to dose measured for a single plastic catheter was 99.8 ± 4.2%. In patient dosimetric results indicate improved coverage of the lateral aspect of vaginal vault with the custom cylinder relative to the standard cylinder; 700 cGy vs 328 cGy, respectively, at a representative lateral vaginal dose point, while simultaneously achieving relatively narrow dose distribution in the anterior/posterior direction. Stereolithographic applicator production was available within a clinically acceptable timeframe, and its clinical feasibility and utility has been demonstrated. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  13. Ground-Based Localization of Mars Rovers

    NASA Technical Reports Server (NTRS)

    Trebi-Ollennu, Ashitey

    2006-01-01

    The document discusses a procedure for localizing the Mars rovers in site frame, a locally defined reference frame on the Martian surface. MER onboard position within a site frame is estimated onboard and is based on wheel odometry. Odometry estimation of rover position is only reliable over relatively short distances assuming no wheel slip, sinkage, etc. As the rover traverses, its onboard estimate of position in the current site frame accumulates errors and will need to be corrected on occasions via relocalization on the ground (mission operations). The procedure provides a systematic process for ground operators to localize the rover. The method focuses on analysis of acquired images used to declare a site frame and images acquired post-drive. Target selection is performed using two main steps. In the first step, the user identifies features of interest from the images used to declare the current site. Each of the selected target s position in site frame is recorded. In the second step, post-traverse measurements of the selected features positions are recorded again, this time in rover frame, using images acquired post-traverse. In the third step, we transform the post-traverse target s positions to local level frame. In the fourth step, we compute the delta differences in the pre- and post-traverse target s position. In the fifth step, we analyze the delta differences with techniques that compute their statistics to determine the rover s position in the site frame.

  14. Decadal Challenges in Ground-Based Observations for Solar and Space Physics (Invited)

    NASA Astrophysics Data System (ADS)

    Robinson, R. M.

    2013-12-01

    Ground-based observations of the sun and near-Earth space have long provided the fundamental information needed to achieve a better understanding of the coupled Sun-Earth system and the processes responsible for solar activity and its effects on Earth's magnetosphere, ionosphere, and atmosphere. Observations based on both active and passive radio wave and optical techniques provide measurements throughout Earth's atmosphere, geospace, the heliosphere, and the Sun. Although the number of observing instruments, the capabilities of the instruments, and the variety of ground-based assets continue to open new frontiers and enable scientific discoveries, gaps still exist, not only in terms of the spatial coverage of the measurements, but also in the properties of the system that are observed and the cadence and frequency of the observations. Fortunately, new technologies have provided the tools by which these challenges can be overcome. This is an opportune time to develop an integrated strategy for development, deployment, operation, and data analysis of ground-based assets. These include, for example, advanced networking technologies, crowd-sourced data acquisition, and multi-use observational platforms. Ground-based observations can also be optimized through the development of smart sensors, that operate at low power and are easily deployable, reconfigurable, and remotely operable. Furthermore, the data from ground-based observations will be collected, archived, and disseminated in ways that will enable effective and productive data mining, image and pattern recognition, cross-correlation among diverse data sets, and broadly-based collaborative research. These capabilities are especially important as we attempt to understand the system aspects of the solar-terrestrial environment. The next decade will undoubtedly see new understanding and discoveries resulting from improved and expanded ground-based instruments, as well as in their strategic deployment and operation.

  15. Fluorescence Imaging and Streamline Visualization of Hypersonic Flow over Rapid Prototype Wind-Tunnel Models

    NASA Technical Reports Server (NTRS)

    Danehy, Paul M.; Alderfer, David W.; Inman, Jennifer A.; Berger, Karen T.; Buck, Gregory M.; Schwartz, Richard J.

    2008-01-01

    Reentry models for use in hypersonic wind tunnel tests were fabricated using a stereolithography apparatus. These models were produced in one day or less, which is a significant time savings compared to the manufacture of ceramic or metal models. The models were tested in the NASA Langley Research Center 31-Inch Mach 10 Air Tunnel. Only a few of the models survived repeated tests in the tunnel, and several failure modes of the models were identified. Planar laser-induced fluorescence (PLIF) of nitric oxide (NO) was used to visualize the flowfields in the wakes of these models. Pure NO was either seeded through tubes plumbed into the model or via a tube attached to the strut holding the model, which provided localized addition of NO into the model s wake through a porous metal cylinder attached to the end of the tube. Models included several 2- inch diameter Inflatable Reentry Vehicle Experiment (IRVE) models and 5-inch diameter Crew Exploration Vehicle (CEV) models. Various model configurations and NO seeding methods were used, including a new streamwise visualization method based on PLIF. Virtual Diagnostics Interface (ViDI) technology, developed at NASA Langley Research Center, was used to visualize the data sets in post processing. The use of calibration "dotcards" was investigated to correct for camera perspective and lens distortions in the PLIF images.

  16. Adaptive Optics for Ground-based Hypertelescopes

    NASA Astrophysics Data System (ADS)

    Labeyrie, Antoine; Borkowski, Virginie; Martinache, Franz; Arnold, Luc; Dejonghe, Julien; Riaud, Pierre; Lardière, Olivier; Gillet, Sophie

    Hypertelescopes, which may be considered as "exploded" versions of an OWL or other ELT, can in principle reach aperture sizes exceeding 1-10 kilometers. They utilize a multi-aperture diluted array and produce direct images through a densified exit pupil. Variants with a flat (the hypertelescope version of the Optical Very Large Array) or spherical (Arecibo-like CARLINA concept) site are studied. Adaptive optics is a major requirement for obtaining direct snapshot images at high resolution. Ways of adapting the Shack-Hartmann and curvature sensing methods for diluted apertures have been proposed. We explore the feasibility of applying 3D Fourier transforms to the dispersed images for extracting the path difference and phase information. With a spherical site, the numerous stars observable simultaneously at large angles can presumably help in the way of atmospheric tomography. Similar optics, equipped with a coronagraph, is proposed to NASA for the Terrestrial Planet Finder. The 3D Fourier transform algorithm also appears applicable in this case for fringe acquisition and π/100 phasing.

  17. Jovian thundercloud research with ground-based telescope and spacecraft

    NASA Astrophysics Data System (ADS)

    Takahashi, Yukihiro; Nakajima, Kensuke; Takeuchi, Satoru; Sugiyama, Ko-Ichiro; Sato, Mitsuteru; Fukuhara, Tetsuya; Sato, Soga; Yair, Yoav; Aplin, Karen; Fischer, Georg

    2010-05-01

    The latest observational and theoretical studies suggest that thunderstorms, i.e., strong moist convective clouds in Jupiter's atmosphere are very important not only as an essential ingredient of meteorology of Jupiter, which determines the large scale structures such as belt/zone and big ovals, but also as a potentially very useful tool for probing the water abundance of the deep atmosphere, which is crucial to constrain the behavior of volatiles in early solar system. Here we suggest a very simple high-speed imaging unit onboard Jovian orbiter, Optical Lightning Detector, OLD, optimized for detecting optical emissions from lightning discharge in Jupiter. OLD consists of radiation-tolerant CMOS sensors and two H Balmer Alpha line (656.3nm) filters. In normal sampling mode the frame intervals is 29ms with a full frame format of 512x512 pixels and in high-speed sampling mode the interval could be reduced down to 0.1ms by concentrating a limited area of 30x30 pixels. Weight, size and power consumption are about 1kg, 16x7x5.5 cm (sensor) and 16x12x4 cm (circuit), and 4W, respectively, though they can be reduced according to the spacecraft resources. Also we plan to investigate the optical flashes using a ground-based middle-sized telescope, which will be built by Hokkaido University, with narrow-band high speed imaging unit. Observational strategy with such optical lightning detectors and spectral imagers, which enable us to estimate the horizontal motion and altitude of clouds, will be introduced.

  18. Space- and Ground-based Coronal Spectro-Polarimetry

    NASA Astrophysics Data System (ADS)

    Fineschi, Silvano; Bemporad, Alessandro; Rybak, Jan; Capobianco, Gerardo

    This presentation gives an overview of the near-future perspectives of ultraviolet and visible-light spectro-polarimetric instrumentation for probing coronal magnetism from space-based and ground-based observatories. Spectro-polarimetric imaging of coronal emission-lines in the visible-light wavelength-band provides an important diagnostics tool of the coronal magnetism. The interpretation in terms of Hanle and Zeeman effect of the line-polarization in forbidden emission-lines yields information on the direction and strength of the coronal magnetic field. As study case, this presentation will describe the Torino Coronal Magnetograph (CorMag) for the spectro-polarimetric observation of the FeXIV, 530.3 nm, forbidden emission-line. CorMag - consisting of a Liquid Crystal (LC) Lyot filter and a LC linear polarimeter - has been recently installed on the Lomnicky Peak Observatory 20cm Zeiss coronagraph. The preliminary results from CorMag will be presented. The linear polarization by resonance scattering of coronal permitted line-emission in the ultraviolet (UV)can be modified by magnetic fields through the Hanle effect. Space-based UV spectro-polarimeters would provide an additional tool for the disgnostics of coronal magnetism. As a case study of space-borne UV spectro-polarimeters, this presentation will describe the future upgrade of the Sounding-rocket Coronagraphic Experiment (SCORE) to include the capability of imaging polarimetry of the HI Lyman-alpha, 121.6 nm. SCORE is a multi-wavelength imager for the emission-lines, HeII 30.4 nm and HI 121.6 nm, and visible-light broad-band emission of the polarized K-corona. SCORE has flown successfully in 2009. This presentation will describe how in future re-flights SCORE could observe the expected Hanle effect in corona with a HI Lyman-alpha polarimeter.

  19. Fiber bundle based endomicroscopy prototype with two collection channels for simultaneous coherent anti-Stokes Raman scattering and second harmonic generation imaging

    NASA Astrophysics Data System (ADS)

    Liu, Zhengfan; Satira, Zachary A.; Wang, Xi; Xu, Xiaoyun; Chen, Xu; Wong, Kelvin; Chen, Shufen; Xin, Jianguo; Wong, Stephen T. C.

    2014-02-01

    Label-free multiphoton imaging is promising for replacing biopsy and could offer new strategies for intraoperative or surgical applications. Coherent anti-Stokes Raman scattering (CARS) imaging could provide lipid-band contrast, and second harmonic generation (SHG) imaging is useful for imaging collagen, tendon and muscle fibers. A combination of these two imaging modalities could provide rich information and this combination has been studied by researchers to investigate diseases through microscopy imaging. The combination of these two imaging modalities in endomicroscopy imaging has been rarely investigated. In this research, a fiber bundle consisted of one excitation fiber and 18 collection fibers was developed in our endomicroscopy prototype. The 18 collection fibers were divided into two collection channels with 9 fibers in each channel. These two channels could be used together as one channel for effective signal collection or used separately for simplifying detection part of the system. Differences of collection pattern of these two channels were investigated. Collection difference of central excitation fiber and surrounding 18 fibers was also investigated, which reveals the potential ability of this system to measure forward to backward (F/B) ratio in SHG imaging. CARS imaging of mouse adipocyte and SHG imaging of mouse tail tendon were performed to demonstrate the CARS and SHG tissue imaging performance of this system. Simultaneous CARS and SHG imaging ability of this system was demonstrated by mouse tail imaging. This fiber bundle based endomicroscopy imaging prototype, offers a promising platform for constructing efficient fiber-based CARS and SHG multimodal endomicroscopes for label free intraoperative imaging applications.

  20. Investigation of the signal behavior at diagnostic energies of prototype, direct detection, active matrix, flat-panel imagers incorporating polycrystalline HgI2

    PubMed Central

    Du, Hong; El-Mohri, Youcef; Zhao, Qihua; Su, Zhong; Yamamoto, Jin; Wang, Yi

    2009-01-01

    Active matrix, flat-panel x-ray imagers based on a-Si:H thin film transistors offer many advantages and are widely utilized in medical imaging applications. Unfortunately, the detective quantum efficiency (DQE) of conventional flat-panel imagers incorporating scintillators or a-Se photoconductors is significantly limited by their relatively modest signal to noise ratio, particularly in applications involving low x-ray exposures or high spatial resolution. For this reason, polycrystalline HgI2 is of considerable interest by virtue of its low effective work function, high atomic number, and the possibility of large-area deposition. In this study, a detailed investigation of the properties of prototype, flat-panel arrays coated with two forms of this high-gain photoconductor are reported. Encouragingly, high x-ray sensitivity, low dark current, and spatial resolution close to the theoretical limits were observed from a number of prototypes. In addition, input-quantum-limited DQE performance was measured from one of the prototypes at relatively low exposures. However, high levels of charge trapping, lag, and polarization, as well as pixel-to-pixel variations in x-ray sensitivity are of concern. While the results of the current study are promising, further development will be required to realize prototypes exhibiting the characteristics necessary to allow practical implementation of this approach. PMID:18296765

  1. Studies of prototype DEPFET sensors for the wide field imager of Athena

    NASA Astrophysics Data System (ADS)

    Treberspurg, Wolfgang; Andritschke, Robert; Bähr, Alexander; Bianchi, Davide; Koch, Anna; Meidinger, Norbert; Müller-Seidlitz, Johannes; Ott, Sabine; Porro, Matteo

    2016-07-01

    The Wide Field Imager of the Athena telescope will combine an excellent spectroscopic performance and high count rate capability with a large field of view. For these purposes, its focal plane consists of two complementary detectors, using DEPFET active pixel sensors. One is the high count rate detector with a small field of view, which has to be operated with a readout speed of 80 μs per frame. In contrast, the large area detector will cover a large field of view and has to be read out with a frame rate <= 5 ms. Its sensitive area is covered by four identical active pixel arrays, consisting of 512 x 512 pixels, each. Since a column parallel readout will be used, 512 pixels are connected to one single channel of a readout ASIC. The readout will be accomplished by either sensing a voltage step on the source node or a change of the transistor drain current. The former so-called source follower mode requires long settling times - proportional to the load capacitances - but can cope with local inhomogeneities. Alternatively, the latter so-called drain current mode provides a fast readout - independent to the load capacitance - but implicates a higher sensitivity on local variations of the DEPFETs bias currents. Both modes are implemented in the VERITAS 2.1 readout ASIC and were studied with 64 x 64 pixels arrays. Drain current devices could be operated with significantly smaller settling times but suffer from a slightly increased noise at similar shaping times in comparison to the source follower ones. By using an optimized timing with dedicated settling and shaping times, the devices of both modes feature a comparable spectral performance.

  2. Ground deformation from ground-based SAR interferometry

    NASA Astrophysics Data System (ADS)

    Tarchi, Dario; Casagli, Nicola; Fortuny-Guasch, Joaquim; Guerri, Letizia; Antonello, Giuseppe; Leva, Davide

    An in-depth analysis of the last two images acquired by the ground-based interferometric synthetic aperture radar system installed on Stromboli before the 5 April 2003 explosion allowed us to detect the precursory signals of the explosion related to ground deformation. In particular, it was possible to estimate the exact time of the explosion through the time domain analysis of raw data from the radar acquisition. This was interrupted by a blackout that occurred a few seconds after the event. The explosion onset time corresponds to a clear change in the intensity of the backscattered energy, related to the dense volcanic plume emission from the Crater. In addiction, the use of a particular interferometric processing technique for the last two acquisitions, consisting of the selection of synthetic sub-apertures from the main ones and creating with these a sequence of interferograms with a higher temporal resolution, detected precursory deformations starting 2 min before the explosion. These observations indicate the occurrence of an elastic deformation of a centimeter amplitude that affected the volcanic edifice progressively from the Crater down to the Sciara del Fuoco depression.

  3. Simultaneous ground-based thermospheric wind measurements using Doppler asymmetric spatial heterodyne spectroscopy (DASH) and Fabry-Perot Interferometry

    NASA Astrophysics Data System (ADS)

    Englert, C. R.; Harlander, J. M.; Meriwether, J. W.; Brown, C. M.; Drob, D. P.; Emmert, J. T.; Castelaz, M.; Roesler, F. L.

    2011-12-01

    The concept of Doppler Asymmetric Spatial Heterodyne (DASH) instruments to measure upper atmospheric winds was initially published in 2006. The DASH approach is identical to the concept of Spatial Heterodyne Spectroscopy (SHS) except that one interferometer arm includes an additional fixed optical path offset, similar to the phase stepping Michelson technique which was used for the WINDII (Wind Imaging Interferometer) experiment. The advantages of DASH include having no moving parts, high sensitivity, and the ability to simultaneously observe multiple isolated emission lines, including a known light source for real time calibration. Since it was first proposed, the development of the DASH technique has progressed significantly. Major milestones include a proof of concept in the laboratory, the design, fabrication and test of a monolithic DASH interferometer for the thermospheric red line (O I 630nm), and initial ground based thermospheric wind measurements using this interferometer. To further increase the technical readiness level (TRL) of DASH for a future satellite instrument, we have conducted coordinated measurements with a DASH prototype and Fabry-Perot interferometer (FPI) from the Pisgah Astronomical Research Institute in North Carolina in the summer of 2011. We will present a comparison of the two experimental data sets and examine how they compare with the empirical horizontal wind model HWM-07.

  4. Probing Pluto's Atmosphere Using Ground-Based Stellar Occultations

    NASA Astrophysics Data System (ADS)

    Sicardy, Bruno; Rio de Janeiro Occultation Team, Granada Team, International Occultation and Timing Association, Royal Astronomical Society New Zealand Occultation Section, Lucky Star associated Teams

    2016-10-01

    Over the last three decades, some twenty stellar occultations by Pluto have been monitored from Earth. They occur when the dwarf planet blocks the light from a star for a few minutes as it moves on the sky. Such events led to the hint of a Pluto's atmosphere in 1985, that was fully confirmed during another occultation in 1988, but it was only in 2002 that a new occultation could be recorded. From then on, the dwarf planet started to move in front of the galactic center, which amplified by a large factor the number of events observable per year.Pluto occultations are essentially refractive events during which the stellar rays are bent by the tenuous atmosphere, causing a gradual dimming of the star. This provides the density, pressure and temperature profiles of the atmosphere from a few kilometers above the surface up to about 250 km altitude, corresponding respectively to pressure levels of about 10 and 0.1 μbar. Moreover, the extremely fine spatial resolution (a few km) obtained through this technique allows the detection of atmospheric gravity waves, and permits in principle the detection of hazes, if present.Several aspects make Pluto stellar occultations quite special: first, they are the only way to probe Pluto's atmosphere in detail, as the dwarf planet is far too small on the sky and the atmosphere is far too tenuous to be directly imaged from Earth. Second, they are an excellent example of participative science, as many amateurs have been able to record those events worldwide with valuable scientific returns, in collaboration with professional astronomers. Third, they reveal Pluto's climatic changes on decade-scales and constrain the various seasonal models currently explored.Finally, those observations are fully complementary to space exploration, in particular with the New Horizons (NH) mission. I will show how ground-based occultations helped to better calibrate some NH profiles, and conversely, how NH results provide some key boundary conditions

  5. Space transfer with ground-based laser/electric propulsion

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Stavnes, Mark; Oleson, Steve; Bozek, John

    1993-01-01

    A new method of providing power to space vehicles consists of using ground-based lasers to beam power to photovoltaic receivers in space. This can be used as a power source for electrically propelled orbital transfer vehicles.

  6. Challenges and Opportunities for Ground-based Helioseismic Observations

    NASA Astrophysics Data System (ADS)

    Chaplin, W. J.

    2013-12-01

    I summarize the current status of ground-based helioseismic observations, in particular the two operational networks GONG and BiSON. I then discuss requirements for continued and future ground-based observations based on key science drivers, finishing with a discussion of SPRING, a proposed future high-spatial-resolution network that would provide helioseismic data and a broad range of synoptic data products.

  7. Teen motherhood and pregnancy prototypes: the role of social context in changing young African American mothers' risk images and contraceptive expectations.

    PubMed

    Barr, Ashley B; Simons, Ronald L; Simons, Leslie Gordon; Gibbons, Frederick X; Gerrard, Meg

    2013-12-01

    Despite the declining rate of teen pregnancies in the United States, academic and public health experts have expressed concern over the still relatively high rate of rapid repeat pregnancies among adolescents, particularly among minority youth. Using a sample of over 300 African American female adolescents, the current study used insights from the prototype/willingness model of adolescent risk behavior to explore this risk. More specifically, it assessed the relationship between entry into unwed motherhood during mid-to-late adolescence and changes in prototypes of unmarried pregnant teens. Further, it explored the extent to which these changing prototypes accounted for young mothers' later contraceptive expectations. We tested the possibility that social images were affected not only by personal experience (the birth of a child) but also by the family and community context in which this experience took place. The findings show that the early entrance into teen motherhood was associated with a shift toward more favorable prototypes of unwed pregnant teens, but that this was only the case for young mothers in disadvantaged contexts. Given this, prototype changes helped to explain the link between teen motherhood and contraceptive expectations only for those in disadvantaged contexts. We discuss these findings in terms of their practical and theoretical implications.

  8. Uncertainties in Instantaneous Rainfall Rate Estimates: Satellite vs. Ground-Based Observations

    NASA Astrophysics Data System (ADS)

    Amitai, E.; Huffman, G. J.; Goodrich, D. C.

    2012-12-01

    High-resolution precipitation intensities are significant in many fields. For example, hydrological applications such as flood forecasting, runoff accommodation, erosion prediction, and urban hydrological studies depend on an accurate representation of the rainfall that does not infiltrate the soil, which is controlled by the rain intensities. Changes in the rain rate pdf over long periods are important for climate studies. Are our estimates accurate enough to detect such changes? While most evaluation studies are focusing on the accuracy of rainfall accumulation estimates, evaluation of instantaneous rainfall intensity estimates is relatively rare. Can a speceborne radar help in assessing ground-based radar estimates of precipitation intensities or is it the other way around? In this presentation we will provide some insight on the relative accuracy of instantaneous precipitation intensity fields from satellite and ground-based observations. We will examine satellite products such as those from the TRMM Precipitation Radar and those from several passive microwave imagers and sounders by comparing them with advanced high-resolution ground-based products taken at overpass time (snapshot comparisons). The ground based instantaneous rain rate fields are based on in situ measurements (i.e., the USDA/ARS Walnut Gulch dense rain gauge network), remote sensing observations (i.e., the NOAA/NSSL NMQ/Q2 radar-only national mosaic), and multi-sensor products (i.e., high-resolution gauge adjusted radar national mosaics, which we have developed by applying a gauge correction on the Q2 products).

  9. Enhancing Ground Based Telescope Performance with Image Processing

    DTIC Science & Technology

    2013-11-13

    of point source irradiance which improves photometry . 60 4.2 The SST Experimental Description As stated in the introduction, the purpose of...Space Telescope Science Institute, NASA, 2006. [52] R. Schödel, "Accurate photometry with adaptive optics in the presence of anisoplanatic effects

  10. Infrared ground-based astronomy with the Hughes 256 X 256 PtSi array

    NASA Technical Reports Server (NTRS)

    Fowler, A.; Joyce, R.; Gatley, I.; Gates, J.; Herring, J.

    1989-01-01

    It is shown that large format PtSi Schottky diode infrared arrays, the Hughes 256 X 256 hybrid Schottky array in particular, are competitive alternatives to the smaller format photovoltaic arrays for ground-based astronomy. The modest quantum efficiency of the PtSi compared to the photovoltaic devices is more than compensated for by the larger format. The use of hybrid technology yields effective fill factors of nearly 100 percent, and the low dark current, noise, excellent imaging characteristics, cost, and solid nitrogen operating temperature add to the effectiveness of this array for ground-based imaging. In addition to discussing the characteristics of this array, researchers present laboratory test data and astronomical results achieved at Kitt Peak.

  11. Low Dose High Energy X-ray In-Line Phase Sensitive Imaging Prototype: Investigation of Optimal Geometric Conditions and Design Parameters

    PubMed Central

    Ghani, Muhammad. U.; Yan, Aimin; Wong, Molly. D.; Li, Yuhua; Ren, Liqiang; Wu, Xizeng; Liu, Hong

    2016-01-01

    The objective of this study was to investigate the optimization of a high energy in-line phase sensitive x-ray imaging prototype under different geometric and operating conditions for mammography application. A phase retrieval algorithm based on phase attenuation duality (PAD) was applied to the phase contrast images acquired by the prototype. Imaging performance was investigated at four magnification values of 1.67, 2, 2.5 and 3 using an acrylic edge, an American College of Radiology (ACR) mammography phantom and contrast detail (CD) phantom with tube potentials of 100, 120 and 140 kVp. The ACR and CD images were acquired at the same mean glandular dose (MGD) of 1.29 mGy with a computed radiography (CR) detector of 43.75 µm pixel pitch at a fixed source to image distance (SID) of 170 cm. The x-ray tube focal spot size was kept constant as 7 µm while a 2.5 mm thick aluminum (Al) filter was used for beam hardening. The performance of phase contrast and phase retrieved images were compared with computer simulations based on the relative phase contrast factor (RPF) at high x-ray energies. The imaging results showed that the x-ray tube operated at 100 kVp under the magnification of 2.5 exhibits superior imaging performance which is in accordance to the computer simulations. As compared to the phase contrast images, the phase retrieved images of the ACR and CD phantoms demonstrated improved imaging contrast and target discrimination. We compared the CD phantom images acquired in conventional contact mode with and without the anti-scatter grid using the same prototype at 1.295 mGy and 2.59 mGy using 40 kVp, a 25 µm rhodium (Rh) filter. At the same radiation dose, the phase sensitive images provided improved detection capabilities for both the large and small discs, while compared to the double dose image acquired in conventional mode, the observer study also indicated that the phase sensitive images provided improved detection capabilities for the large discs. This

  12. Low dose high energy x-ray in-line phase sensitive imaging prototype: Investigation of optimal geometric conditions and design parameters.

    PubMed

    Ghani, Muhammad U; Yan, Aimin; Wong, Molly D; Li, Yuhua; Ren, Liqiang; Wu, Xizeng; Liu, Hong

    2015-01-01

    The objective of this study was to investigate the optimization of a high energy in-line phase sensitive x-ray imaging prototype under different geometric and operating conditions for mammography application. A phase retrieval algorithm based on phase attenuation duality (PAD) was applied to the phase contrast images acquired by the prototype. Imaging performance was investigated at four magnification values of 1.67, 2, 2.5 and 3 using an acrylic edge, an American College of Radiology (ACR) mammography phantom and contrast detail (CD) phantom with tube potentials of 100, 120 and 140 kVp. The ACR and CD images were acquired at the same mean glandular dose (MGD) of 1.29 mGy with a computed radiography (CR) detector of 43.75 μm pixel pitch at a fixed source to image distance (SID) of 170 cm. The x-ray tube focal spot size was kept constant as 7 μm while a 2.5 mm thick aluminum (Al) filter was used for beam hardening. The performance of phase contrast and phase retrieved images were compared with computer simulations based on the relative phase contrast factor (RPF) at high x-ray energies. The imaging results showed that the x-ray tube operated at 100 kVp under the magnification of 2.5 exhibits superior imaging performance which is in accordance to the computer simulations. As compared to the phase contrast images, the phase retrieved images of the ACR and CD phantoms demonstrated improved imaging contrast and target discrimination. We compared the CD phantom images acquired in conventional contact mode with and without the anti-scatter grid using the same prototype at 1.295 mGy and 2.59 mGy using 40 kVp, a 25 μm rhodium (Rh) filter. At the same radiation dose, the phase sensitive images provided improved detection capabilities for both the large and small discs, while compared to the double dose image acquired in conventional mode, the observer study also indicated that the phase sensitive images provided improved detection capabilities for the large discs. This

  13. From static to dynamic 1.5T MRI-linac prototype: impact of gantry position related magnetic field variation on image fidelity.

    PubMed

    Crijns, Sjoerd; Raaymakers, Bas

    2014-07-07

    Recently, the MRI-linac prototype at UMC Utrecht was upgraded with a ring-based gantry, where all linac components are mounted on a ring around the MR scanner. Although adaptations have been made to both linac and MR magnets in order to account for mutual magnetic interference, interference problems cannot be ruled out completely. Therefore, in this paper the impact of gantry position dependent magnetic field inhomogeneity variation on the geometrical accuracy of acquired MR images is quantified. Magnetic field maps were acquired in a large field of view for static gantry positions in shimmed and un-shimmed conditions. Reproducibility of the shim settings was assessed. From the fieldmaps, a minimum gradient strength needed to acquire images with geometric distortions of, at most, 1 mm was derived. Moreover, imaging during gantry rotation was performed for a range of imaging parameters and rotation speeds. From the measurements we conclude that images with good geometric fidelity can be obtained for all static gantry positions, provided that shimming is performed for each new gantry position. This indicates that the present prototype is suitable for static IMRT scenarios. Shim settings are highly reproducible, suggesting that shimming via look-up tables is feasible. Finally, imaging during gantry rotation may produce severely distorted images at present and is likely to require advanced compensation methods such as dynamic shimming or higher order reconstruction.

  14. Long term landslide monitoring with Ground Based SAR

    NASA Astrophysics Data System (ADS)

    Monserrat, Oriol; Crosetto, Michele; Luzi, Guido; Gili, Josep; Moya, Jose; Corominas, Jordi

    2014-05-01

    In the last decade, Ground-Based (GBSAR) has proven to be a reliable microwave Remote Sensing technique in several application fields, especially for unstable slopes monitoring. GBSAR can provide displacement measurements over few squared kilometres areas and with a very high spatial and temporal resolution. This work is focused on the use of GBSAR technique for long term landslide monitoring based on a particular data acquisition configuration, which is called discontinuous GBSAR (D-GBSAR). In the most commonly used GBSAR configuration, the radar is left installed in situ, acquiring data periodically, e.g. every few minutes. Deformations are estimated by processing sets of GBSAR images acquired during several weeks or months, without moving the system. By contrast, in the D-GBSAR the radar is installed and dismounted at each measurement campaign, revisiting a given site periodically. This configuration is useful to monitor slow deformation phenomena. In this work, two alternative ways for exploiting the D-GBSAR technique will be presented: the DInSAR technique and the Amplitude based Technique. The former is based on the exploitation of the phase component of the acquired SAR images and it allows providing millimetric precision on the deformation estimates. However, this technique presents several limitations like the reduction of measurable points with an increase in the period of observation, the ambiguous nature of the phase measurements, and the influence of the atmospheric phase component that can make it non applicable in some cases, specially when working in natural environments. The second approach, that is based on the use of the amplitude component of GB-SAR images combined with a image matching technique, will allow the estimation of the displacements over specific targets avoiding two of the limitations commented above: the phase unwrapping and atmosphere contribution but reducing the deformation measurement precision. Two successful examples of D

  15. New layer-based imaging and rapid prototyping techniques for computer-aided design and manufacture of custom dental restoration.

    PubMed

    Lee, M-Y; Chang, C-C; Ku, Y C

    2008-01-01

    Fixed dental restoration by conventional methods greatly relies on the skill and experience of the dental technician. The quality and accuracy of the final product depends mostly on the technician's subjective judgment. In addition, the traditional manual operation involves many complex procedures, and is a time-consuming and labour-intensive job. Most importantly, no quantitative design and manufacturing information is preserved for future retrieval. In this paper, a new device for scanning the dental profile and reconstructing 3D digital information of a dental model based on a layer-based imaging technique, called abrasive computer tomography (ACT) was designed in-house and proposed for the design of custom dental restoration. The fixed partial dental restoration was then produced by rapid prototyping (RP) and computer numerical control (CNC) machining methods based on the ACT scanned digital information. A force feedback sculptor (FreeForm system, Sensible Technologies, Inc., Cambridge MA, USA), which comprises 3D Touch technology, was applied to modify the morphology and design of the fixed dental restoration. In addition, a comparison of conventional manual operation and digital manufacture using both RP and CNC machining technologies for fixed dental restoration production is presented. Finally, a digital custom fixed restoration manufacturing protocol integrating proposed layer-based dental profile scanning, computer-aided design, 3D force feedback feature modification and advanced fixed restoration manufacturing techniques is illustrated. The proposed method provides solid evidence that computer-aided design and manufacturing technologies may become a new avenue for custom-made fixed restoration design, analysis, and production in the 21st century.

  16. Ground-based and spacecraft-based data sets: examples of synergy from recent missions

    NASA Astrophysics Data System (ADS)

    Buratti, Bonnie; Hicks, Michael; Bauer, James

    2015-08-01

    Missions to small bodies have returned a wealth of observations at high spatial resolution and new wavelengths. Nevertheless, spacecraft data is often deficient in many ways, lacking in temporal coverage, specific viewing geometries, context, spectral range, and calibrations. Several recent examples illustrate how modest ground-based “support” measurements for missions to small bodies have substantially enhanced the results from these missions. Triton, Neptune’s giant moon, was observed by Voyager 2 in 1989: high resolution images showed a sublimating polar cap and explosive plumes of volatiles. This instant in time was placed into context by subsequent ground-based and HST observations of the moon that showed continued volatile transport. Similarly, decades of ground-based observations leading up to the New Horizons fast flyby of Pluto monitored long-term changes in frosts on the dwarf planet’s surface. Another example of synergistic measurements for small-body missions is that of complementary solar phase angle coverage. Space-based missions seldom have small phase angle measurements; similarly, ground-based measurements are often lacking at large solar phase angles (except of course for NEOs). This complementary phase angle coverage enables accurate photometric modeling, including determination of the bolometric Bond albedo, which is a key parameter for thermal modeling. Another key use of ground-based observations is to check and refine spacecraft calibrations, at least at wavelengths that are visible from Earth. In some cases, complete calibration sets are provided by Earth-based observing programs, such as that of ROLO (RObotic Lunar Observatory) for the Moon. Finally, context and the “big picture” in both time and space are provided by telescopic views of spacecraft targets before, during, and after mission durations or critical events.The astronomical community should continue to support, and participate in, teams that make synergistic

  17. Greenbrier Prototype

    SciTech Connect

    2010-06-18

    This case study describes a prototype home that is the model home for the Homes at Greenbrier in Oakdale, Connecticut, and demonstrates the builder's concept of “attainable sustainable” of offering high performance homes at mid-market prices.

  18. Microgravity Investigation of Crew Reactions in 0-G (MICR0-G): Ground-Based Development Effort

    NASA Technical Reports Server (NTRS)

    Newman, Dava J.

    2002-01-01

    This report describes the technology development of an advanced load sensor ground-based prototype and details the preliminary tests in microgravity during parabolic flights. The research effort is entitled, the Microgravity Investigation and Crew Reactions in 0-G (MICR0-G), a ground-based research effort funded by the National Aeronautics and Space Administration (NASA). The MICR0-G project was a follow-on to the Enhanced Dynamic Load Sensors (EDLS) spaceflight experiment flown on the Russian Space Station Mir. The technology development of the advanced load sensor prototype has been carried out by the Massachusetts Institute of Technology (MIT), with collaboration from Politecnico di Milano University and the Italian Space Agency (ASI). The key hardware of the advanced sensor prototype is a set of two types of load sensors - a hand-hold and foot restraints - similar in appearance to the mobility aids found in the Space Shuttle orbiter to assist the crew in moving inside the spacecraft, but able to measure the applied forces and moments about the x-, y-, and z- axes. The aim of Chapter 1 is to give a brief overview of the report contents. The first section summarizes the previous research efforts on astronaut-induced loads in microgravity. The second section provides information on the MICR0-G research project and the technology development work conducted at MIT. Section 1.3 details the motivation for designing a new generation of load sensors and describes the main enhancements and contributions of the MICR0-G advanced load sensors system compared to the EDLS system. Finally, the last section presents the outline of the report.

  19. MAD-4-MITO, a multi array of detectors for ground-based mm/submm SZ observations

    NASA Astrophysics Data System (ADS)

    Lamagna, L.; de Petris, M.; Melchiorri, F.; Battistelli, E.; de Grazia, M.; Luzzi, G.; Orlando, A.; Savini, G.

    2002-05-01

    The last few years have seen a large development of mm technology and ultra-sensitive detectors devoted to microwave astronomy and astrophysics. The possibility to deal with large numbers of these detectors assembled into multi-pixel imaging systems has greatly improved the performance of microwave observations, even from ground-based stations, especially combining the power of multi-band detectors with their new imaging capabilities. Hereafter, we will present the development of a multi-pixel solution devoted to Sunyaev-Zel'dovich observations from ground-based telescopes, that is going to be operated from the Millimeter and Infrared Testagrigia Observatory. .

  20. Ground-based Measurements of Next Generation Spectroradiometric Standard Stars

    NASA Astrophysics Data System (ADS)

    McGraw, John T.

    2013-01-01

    Accurate, radiometric standards are essential to the future of ground- and space-based astronomy and astrophysics. While astronomers tend to think of “standard stars” as available calibration sources, progress at NIST to accurately calibrate inexpensive, easy to use photodiode detectors as spectroradiometric standards from 200 nm to 1800 nm allows referencing astronomical measurements to these devices. Direction-, time-, and wavelength-dependent transmission of Earth’s atmosphere is the single largest source of error for ground-based radiometric measurement of astronomical objects. Measurements and impacts of atmospheric extinction - scattering and absorption - on imaging radiometric and spectroradiometric measurements are described. The conclusion is that accurate real-time measurement of extinction in the column of atmosphere through which standard star observations are made, over the spectral region being observed and over the field of view of the telescope are required. New techniques to directly and simultaneously measure extinction in the column of atmosphere through which observations are made are required. Our direct extinction measurement solution employs three small facility-class instruments working in parallel: a lidar to measure rapidly time variable transmission at three wavelengths with uncertainty of 0.25% per airmass, a spectrophotometer to measure rapidly wavelength variable extinction with sub-1% precision per nanometer resolution element from 350 to 1050nm, and a wide-field camera to measure angularly variable extinction over the field of view. These instruments and their operation will be described. We assert that application of atmospheric metadata provided by this instrument suite corrects for a significant fraction of systematic errors currently limiting radiometric precision, and provides a major step towards measurements that are provably dominated by random noise.

  1. Multispectral mapping of the lunar surface using ground-based telescopes

    NASA Technical Reports Server (NTRS)

    Mccord, T. B.; Feierberg, M. A.; Pieters, C.

    1976-01-01

    Images of the lunar surface were obtained at several wavelengths using a silicon vidicon imaging system and ground-based telescopes. These images were recorded and processed in digital form so that quantitative information was preserved. The photometric precision of the images is shown to be better than 1%. Ratio images calculated by dividing images obtained at two wavelengths (0.40/0.56 and 0.95/0.56 microns) are presented for about 50% of the lunar frontside. Spatial resolution is about 2 km at the subearth point. A complex of distinct units is evident in the images. Earlier work with the reflectance spectrum of lunar materials indicates that, for the most part, these units are compositionally distinct.

  2. Ground Base Skylab Electron Beam Welds in Tantalum

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Comparison of ground-based (left) and Skylab (right) electron beam welds in pure tantalum (Ta) (10X magnification). Residual votices left behind in the ground-based sample after the electron beam passed were frozen into the grain structure. These occurred because of the rapid cooling rate at the high temperature. Although the thermal characteristics and electron beam travel speeds were comparable for the skylab sample, the residual vortices were erased in the grain structure. This may have been due to the fact that final grain size of the solidified material was smaller in the Skylab sample compared to the ground-based sample. The Skylab sample was processed in the M512 Materials Processing Facility (MPF) during Skylab SL-2 Mission. Principal Investigator was Richard Poorman.

  3. Software Prototyping

    PubMed Central

    Del Fiol, Guilherme; Hanseler, Haley; Crouch, Barbara Insley; Cummins, Mollie R.

    2016-01-01

    Summary Background Health information exchange (HIE) between Poison Control Centers (PCCs) and Emergency Departments (EDs) could improve care of poisoned patients. However, PCC information systems are not designed to facilitate HIE with EDs; therefore, we are developing specialized software to support HIE within the normal workflow of the PCC using user-centered design and rapid prototyping. Objective To describe the design of an HIE dashboard and the refinement of user requirements through rapid prototyping. Methods Using previously elicited user requirements, we designed low-fidelity sketches of designs on paper with iterative refinement. Next, we designed an interactive high-fidelity prototype and conducted scenario-based usability tests with end users. Users were asked to think aloud while accomplishing tasks related to a case vignette. After testing, the users provided feedback and evaluated the prototype using the System Usability Scale (SUS). Results Survey results from three users provided useful feedback that was then incorporated into the design. After achieving a stable design, we used the prototype itself as the specification for development of the actual software. Benefits of prototyping included having 1) subject-matter experts heavily involved with the design; 2) flexibility to make rapid changes, 3) the ability to minimize software development efforts early in the design stage; 4) rapid finalization of requirements; 5) early visualization of designs; 6) and a powerful vehicle for communication of the design to the programmers. Challenges included 1) time and effort to develop the prototypes and case scenarios; 2) no simulation of system performance; 3) not having all proposed functionality available in the final product; and 4) missing needed data elements in the PCC information system. PMID:27081404

  4. Prototypes of Lanthanide(III) Agents Responsive to Enzymatic Activities in Three Complementary Imaging Modalities: Visible/Near-Infrared Luminescence, PARACEST-, and T1-MRI.

    PubMed

    He, Jiefang; Bonnet, Célia S; Eliseeva, Svetlana V; Lacerda, Sara; Chauvin, Thomas; Retailleau, Pascal; Szeremeta, Frederic; Badet, Bernard; Petoud, Stéphane; Tóth, Éva; Durand, Philippe

    2016-03-09

    We report first prototypes of responsive lanthanide(III) complexes that can be monitored independently in three complementary imaging modalities. Through the appropriate choice of lanthanide(III) cations, the same reactive ligand can be used to form complexes providing detection by (i) visible (Tb(3+)) and near-infrared (Yb(3+)) luminescence, (ii) PARACEST- (Tb(3+), Yb(3+)), or (iii) T1-weighted (Gd(3+)) MRI. The use of lanthanide(III) ions of different natures for these imaging modalities induces only a minor change in the structure of complexes that are therefore expected to have a single biodistribution and cytotoxicity.

  5. Interactive dynamic three-dimensional scene for the ground-based three-dimensional display

    NASA Astrophysics Data System (ADS)

    Hou, Peining; Sang, Xinzhu; Guo, Nan; Chen, Duo; Yan, Binbin; Wang, Kuiru; Dou, Wenhua; Xiao, Liquan

    2016-10-01

    Three-dimensional (3D) displays provides valuable tools for many fields, such as scientific experiment, education, information transmission, medical imaging and physical simulation. Ground based 360° 3D display with dynamic and controllable scene can find some special applications, such as design and construction of buildings, aeronautics, military sand table and so on. It can be utilized to evaluate and visualize the dynamic scene of the battlefield, surgical operation and the 3D canvas of art. In order to achieve the ground based 3D display, the public focus plane should be parallel to the camera's imaging planes, and optical axes should be offset to the center of public focus plane in both vertical and horizontal directions. Virtual cameras are used to display 3D dynamic scene with Unity 3D engine. Parameters of virtual cameras for capturing scene are designed and analyzed, and locations of virtual cameras are determined by the observer's eye positions in the observing space world. An interactive dynamic 3D scene for ground based 360° 3D display is demonstrated, which provides high-immersion 3D visualization.

  6. Integrating ground-based EO data in satellite-based systems

    SciTech Connect

    Jennings, S.V.; Daugherty, P.; Yow, T.G.

    1997-02-01

    Earth observation (EO) and other forms of geo-referenced data are typically thought of as being ``satellite data.`` It is true that the majority of EO data are satellite oriented; thus, most on-line EO data systems are designed primarily for satellite image data. However, there is A small but significant minority of EO data that is not satellite image data; i.e., it is ground-based or terrestrial data Unfortunately, many on-line systems designed for satellite data do not take into account the somewhat different nature of associated ground-based data, Data queries that work most of the time but fail because the system has not taken into account less common data are not robust enough for today`s users. In order to avoid embarrassing problems, EO system designers must be aware of the nature of ground- based data. In this paper we describe some of our insights on this subject in the hope that the designers of other systems may learn from our experience.

  7. Ground-based laser radar measurements of satellite vibrations.

    PubMed

    Schultz, K I; Fisher, S

    1992-12-20

    Vibration signatures from the low-power atmospheric compensation (LACE) satellite are obtained by using the MIT Lincoln Laboratory Firepond coherent CO(2) laser radar facility located in Westford, Mass. The LACE satellite is equipped with IR germanium retroreflectors on deployable/retractable booms to enhance ground-based IR laser radar measurements of on-orbit boom vibrations. Analysis of pulsed cw laser radar measurements of the satellite during and subsequent to boom retraction indicates the presence of a complex time-varying model structure. The observed vibration spectra include vibration modes not previously predicted. These data represent the first observations of satellite vibration modes from a ground-based laser radar.

  8. Cloud-Base-Height Estimation from Paired Ground-Based Hemispherical Observations

    SciTech Connect

    Kassianov, Evgueni I.; Long, Charles N.; Christy, Jason E.

    2005-08-01

    The Total Sky Imager (TSI) and Hemispheric Sky Imager (HSI) each have a hemispherical field-of-view (FOV) and many TSIs are now deployed. Currently, these instruments have been used routinely to provide a time series of the fractional sky cover only. In this study, we examine the possible retrieval of cloud base height (CBH) from TSI surface observations. This paper presents a validation analysis of a new retrieval using both a model-output inverse problem and independent, ground-based Micropulse Lidar data. The obtained results suggest that, at least for single layer cloud fields, moderately accurate (within ~0.35 km) CBH retrieval is possible.

  9. Preliminary design document: Ground based testbed for avionics systems

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The design and interface requirements for an avionics Ground Based Test bed (GBT) to support Heavy Lift Cargo Vehicles (HLCV) is presented. It also contains data on the vehicle subsystem configurations that are to be supported during their early, pre-PDR developmental phases. Several emerging technologies are also identified for support. A Preliminary Specification Tree is also presented.

  10. GLAST and Ground-Based Gamma-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2008-01-01

    The launch of the Gamma-ray Large Area Space Telescope together with the advent of a new generation of ground-based gamma-ray detectors such as VERITAS, HESS, MAGIC and CANGAROO, will usher in a new era of high-energy gamma-ray astrophysics. GLAST and the ground based gamma-ray observatories will provide highly complementary capabilities for spectral, temporal and spatial studies of high energy gamma-ray sources. Joint observations will cover a huge energy range, from 20 MeV to over 20 TeV. The LAT will survey the entire sky every three hours, allowing it both to perform uniform, long-term monitoring of variable sources and to detect flaring sources promptly. Both functions complement the high-sensitivity pointed observations provided by ground-based detectors. Finally, the large field of view of GLAST will allow a study of gamma-ray emission on large angular scales and identify interesting regions of the sky for deeper studies at higher energies. In this poster, we will discuss the science returns that might result from joint GLAST/ground-based gamma-ray observations and illustrate them with detailed source simulations.

  11. GLAST and Ground-Based Gamma-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2008-01-01

    The launch of the Gamma-ray Large Area Space Telescope together with the advent of a new generation of ground-based gamma-ray detectors such as VERITAS, HESS, MAGIC and CANGAROO, will usher in a new era of high-energy gamma-ray astrophysics. GLAST and the ground based gamma-ray observatories will provide highly complementary capabilities for spectral, temporal and spatial studies of high energy gamma-ray sources. Joint observations will cover a huge energy range, from 20 MeV to over 20 TeV. The LAT will survey the entire sky every three hours, allowing it both to perform uniform, long-term monitoring of variable sources and to detect flaring sources promptly. Both functions complement the high-sensitivity pointed observations provided by ground-based detectors. Finally, the large field of view of GLAST will allow a study of gamma-ray emission on large angular scales and identify interesting regions of the sky for deeper studies at higher energies. In this poster, we will discuss the science returns that might result from joint GLAST/ground-based gamma-ray observations and illustrate them with detailed source simulations.

  12. Vigilant Eagle: ground-based countermeasure system against MANPADS

    NASA Astrophysics Data System (ADS)

    Vollin, Jeff

    2006-05-01

    Man-Portable Air Defense Systems, or MANPADS, have arisen as a major threat to commercial and military air traffic. While no MANPADS attacks have yet occurred within the United States, the risk posed by these weapons is undeniable. MANPADS were originally developed by the Soviet Union and the United States for tactical air defense, but since then these weapons have proliferated around the world. Two major approaches to countering these weapons have arisen: aircraft based and ground based. Aircraft-based systems typically use either flares or lasers to either confuse or blind the oncoming missile, thus driving it off target. These systems have been in use for many years on military aircraft and have been proven effective. However, when one considers the commercial air travel industry, the cost of providing a countermeasure system on every plane becomes prohibitive. A ground-based system by contrast protects every aircraft arriving or departing from an airport. By deploying a ground-based system at high-traffic and hub airports, a large percentage of the flying public can be protected affordably. Vigilant Eagle is such a ground based system which uses High Power Microwaves (HPM) to accomplish this mission.

  13. A ground-based experiment for CMBR anisotropy observations: MITO

    NASA Astrophysics Data System (ADS)

    De Petris, M.; Mainella, G.; Nerozzi, A.; de Bernardis, P.; Garavini, G.; Granata, S.; Guarini, G.; Masi, S.; Melchiorri, B.; Melchiorri, F.; Nobili, S.; Orlando, A.; Palummo, L.; Pisano, G.; Terracina, A.

    1999-07-01

    Ground-based observations at millimeter wavelengths are still competitive with space observatories if inevitable foreground contamination is considered at all stages of data acquisition and analysis. Technical solutions together with carefully chosen cosmological targets and observational strategies are the key points in the development of the MITO experiment.

  14. Modeling ground-based timber harvesting systems using computer simulation

    Treesearch

    Jingxin Wang; Chris B. LeDoux

    2001-01-01

    Modeling ground-based timber harvesting systems with an object-oriented methodology was investigated. Object-oriented modeling and design promote a better understanding of requirements, cleaner designs, and better maintainability of the harvesting simulation system. The model developed simulates chainsaw felling, drive-to-tree feller-buncher, swing-to-tree single-grip...

  15. Ground-Based Sensing System for Weed Mapping in Cotton

    USDA-ARS?s Scientific Manuscript database

    A ground-based weed mapping system was developed to measure weed intensity and distribution in a cotton field. The weed mapping system includes WeedSeeker® PhD600 sensor modules to indicate the presence of weeds between rows, a GPS receiver to provide spatial information, and a data acquisition and ...

  16. Synergy benefit in temperature, humiditiy and cloud property profiling by integrating ground based and satellite measurements

    NASA Astrophysics Data System (ADS)

    Ebell, K.; Orlandi, E.; Hünerbein, A.; Crewell, S.; Löhnert, U.

    2012-12-01

    Accurate, highly vertically resolved temperature, humidity and cloud property profiles are needed for many applications. They are essential for climate monitoring, a better process understanding and the subsequent improvement of parameterizations in numerical weather prediction and climate models. In order to provide such profiles with a high temporal resolution, multiple wavelength active and passive remote sensing techniques available at ground based observatories, e.g. the Atmospheric Radiation Measruement (ARM) Program and Cloudnet facilities, need to be exploited. In particular, the Integrated Profiling Technique (IPT, Löhnert et al., 2008) has been successfully applied to simultaneously derive profiles of temperature, humidity and liquid water by a Bayesian based retrieval using a combination of ground based microwave radiometer, cloud radar and a priori information. Within the project ICOS (Integrating Cloud Observations from Ground and Space - a Way to Combine Time and Space Information), we develop a flexible IPT, which allows for the combination of a variety of ground based measurements from cloud radar, microwave radiometer (MWR) and IR spectrometer as well as satellite based information from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) onboard of METEOSAT. As ground based observations are mainly sensitive to the lower parts of the troposphere, the satellite measurements provide complementary information and are thus expected to improve the estimates of the thermodynamic and cloud property profiles, i. e. hydrometeor content and effective radius, considerably. In addition to the SEVIRI IR measurements, which are provided with a high repetition time, information from polar orbiting satellites could be included. In paticular, the potential of the Advanced Microwave Sounding Unit-A (AMSU-A) and Microwave Sounding Unit (MHS) in the retrieval is investigated. In order to understand the improvement by integrating the measurements of the above

  17. Development of a prototype chest digital tomosynthesis (CDT) R/F system with fast image reconstruction using graphics processing unit (GPU) programming

    NASA Astrophysics Data System (ADS)

    Choi, Sunghoon; Lee, Seungwan; Lee, Haenghwa; Lee, Donghoon; Choi, Seungyeon; Shin, Jungwook; Seo, Chang-Woo; Kim, Hee-Joung

    2017-03-01

    Digital tomosynthesis offers the advantage of low radiation doses compared to conventional computed tomography (CT) by utilizing small numbers of projections ( 80) acquired over a limited angular range. It produces 3D volumetric data, although there are artifacts due to incomplete sampling. Based upon these characteristics, we developed a prototype digital tomosynthesis R/F system for applications in chest imaging. Our prototype chest digital tomosynthesis (CDT) R/F system contains an X-ray tube with high power R/F pulse generator, flat-panel detector, R/F table, electromechanical radiographic subsystems including a precise motor controller, and a reconstruction server. For image reconstruction, users select between analytic and iterative reconstruction methods. Our reconstructed images of Catphan700 and LUNGMAN phantoms clearly and rapidly described the internal structures of phantoms using graphics processing unit (GPU) programming. Contrast-to-noise ratio (CNR) values of the CTP682 module of Catphan700 were higher in images using a simultaneous algebraic reconstruction technique (SART) than in those using filtered back-projection (FBP) for all materials by factors of 2.60, 3.78, 5.50, 2.30, 3.70, and 2.52 for air, lung foam, low density polyethylene (LDPE), Delrin® (acetal homopolymer resin), bone 50% (hydroxyapatite), and Teflon, respectively. Total elapsed times for producing 3D volume were 2.92 s and 86.29 s on average for FBP and SART (20 iterations), respectively. The times required for reconstruction were clinically feasible. Moreover, the total radiation dose from our system (5.68 mGy) was lower than that of conventional chest CT scan. Consequently, our prototype tomosynthesis R/F system represents an important advance in digital tomosynthesis applications.

  18. A Comparison of Sunspot Photometric Indices From Ground-Based Data and MDI/SOHO

    NASA Astrophysics Data System (ADS)

    Chapman, G.; Monaco, R.

    2006-12-01

    Comparing ground-based and space-based sunspot photometric indices is useful in extending the time series for studying variatons in total solar irradiance (TSI). Photometric sunspot indices from CFDT2 images obtained at the San Fernando Observatory have been compared with those from images obtained by MDI/SOHO and the Mauna Loa PSPT. We find very high correlations between them (R greater than about 0.99 for most). However, sunspot darkness is overestimated using MDI images by between 10 to 20 %. A composite sunspot deficit created from red and blue SFO/CFDT2 images correlates well (R =.99, n=53) with deficits from PSPT red images. This work has been partially supported by grants from NASA (NAG5-12905) and the NSF (ATM-0533511).

  19. A Comparison of Sunspot Photometric Indices from Ground-Based Data and MDI/SOHO

    NASA Astrophysics Data System (ADS)

    Chapman, Gary A.; Monaco, R. J.

    2006-06-01

    Comparing ground-based and space-based sunspot photometric indices is useful in extending the time series for studying variations in total solar irradiance (TSI). Photometric sunspot indices from CFDT2 images obtained at the San Fernando Observatory have been compared with those from images obtained by MDI/SOHO and the Mauna Loa PSPT. We find very high correlations between them (R greater than about 0.99 for most). However, sunspot darkness is overestimated using MDI images by between 10 to 20%. A composite sunspot deficit created from red and blue SFO/CFDT2 images correlates well (R = 0.99, n=53) with deficits from PSPT red images. This work has been partly supported by grants from NASA (NAG5-12905) and the NSF (ATM-0533511).

  20. Initial Ground-based Thermospheric Wind Measurements Using Doppler Asymmetric Spatial Heterodyne Spectroscopy (DASH)

    NASA Astrophysics Data System (ADS)

    Englert, C. R.; Harlander, J.; Emmert, J. T.; Babcock, D. D.; Roesler, F. L.

    2010-12-01

    The Doppler Asymmetric Spatial Heterodyne (DASH) concept has recently been proposed to measure upper atmospheric winds. The DASH approach is identical to the concept of Spatial Heterodyne Spectroscopy (SHS) except that one interferometer arm exhibits an additional optical path offset, similar to the phase stepping Michelson technique which was used for the WINDII (Wind Imaging Interferometer) experiment. DASH therefore can be viewed as an optical remote sensing concept that is a hybrid of these two interferometric techniques. Its advantages include no moving parts, high sensitivity, and the ability to simultaneously observe a known light source for real time calibration. Both SHS and phase stepping Michelson instruments have already flown successfully on Earth orbiting satellites (SHIMMER on STPSat-1, WINDII on UARS) and DASH has been demonstrated successfully in the laboratory, which provides significant heritage for DASH. To further mitigate the risk of a future DASH satellite instrument, we built a brassboard DASH instrument, that is capable of measuring thermospheric winds from the ground, using the atomic oxygen red line emission OI(3P-1D) at λ=630nm. Such ground based Doppler shift measurements are routinely performed at many ground stations across the globe, typically using Fabry-Perot interferometers. A ground based DASH instrument gives us the opportunity to demonstrate thermospheric wind measurements using an atmospheric emission feature that is also suitable for space borne measurements. We will present the design of the Redline DASH Demonstration Instrument (REDDI) and the results of the initial ground based thermospheric wind observations. These successful ground based observations further increase the maturity of the DASH technique.

  1. A prototype of image-guided outcome analysis for prostate proton therapy patients based on DICOM-RT ePR

    NASA Astrophysics Data System (ADS)

    Le, Anh; Documet, Jorge; Sullivan, Ashley; Liu, Brent

    2009-02-01

    Last year, we presented the infrastructure for a medical imaging informatics DICOM-RT based ePR system for patients treated with Proton Therapy (PT). The ePR has functionality to integrate patients' imaging and informatics data and perform outcomes analysis with patient and physician profiling in order to provide clinical decision support and suggest courses of treatment. In this paper, we present the development of a prototype for the image-guided outcomes analysis for prostate cancer patient based on DICOM-RT ePR. This ePR system, using DICOM-RT and DICOM-ION objects as well as clinical and biological parameters, provides tools to evaluate treatment plans and assess the outcomes of the patient's treatment; hence, it promotes more successful treatment planning for new prostate cancer patients treated with proton therapy.

  2. Ground-based Space Weather Monitoring with LOFAR

    NASA Astrophysics Data System (ADS)

    Wise, Michael; van Haarlem, Michiel; Lawrence, Gareth; Reid, Simon; Bos, Andre; Rawlings, Steve; Salvini, Stef; Mitchell, Cathryn; Soleimani, Manuch; Amado, Sergio; Teresa, Vital

    As one of the first of a new generation of radio instruments, the International LOFAR Telescope (ILT) will provide a number of unique and novel capabilities for the astronomical community. These include remote configuration and operation, dynamic real-time processing and system response, and the ability to provide multiple simultaneous streams of data to a community whose scientific interests run the gamut from lighting in the atmospheres of distant planets to the origins of the universe itself. The LOFAR (LOw Frequency ARray) system is optimized for a frequency range from 30-240 MHz and consists of multiple antenna fields spread across Europe. In the Netherlands, a total 36 LOFAR stations are nearing completion with an initial 8 international stations currently being deployed in Germany, France, Sweden, and the UK. Digital beam-forming techniques make the LOFAR system agile and allow for rapid repointing of the telescope as well as the potential for multiple simultaneous observations. With its dense core array and long interferometric baselines, LOFAR has the potential to achieve unparalleled sensitivity and spatial resolution in the low frequency radio regime. LOFAR will also be one of the first radio observatories to feature automated processing pipelines to deliver fully calibrated science products to its user community. As we discuss in this presentation, the same capabilities that make LOFAR a powerful tool for radio astronomy also provide an excellent platform upon which to build a ground-based monitoring system for space weather events. For example, the ability to monitor Solar activity in near real-time is one of the key scientific capabilities being developed for LOFAR. With only a fraction of its total observing capacity, LOFAR will be able to provide continuous monitoring of the Solar spectrum over the entire 10-240 MHz band down to microsecond timescales. Autonomous routines will scan these incoming spectral data for evidence of Solar flares and be

  3. Bridging the gap between ground-based and space-based observations of the night airglow

    NASA Astrophysics Data System (ADS)

    Broadfoot, A. L.; Bellaire, Paul J.

    1999-08-01

    Data sets from most satellite experiments focus on global dynamics by integrating daily conditions over long periods, rather than local dynamics over short timescales. Reports from the ground-based 1993 airborne lidar and observations of the Hawaiian airglow/airborne noctilucent cloud campaigns (ALOHA/ANLC-93), with their high temporal and spatial resolution, have described the dynamic nature of the night airglow, or nightglow. Recognizing this dynamic activity, we note that space-based observations currently made from satellites will only poorly complement ground-based observations. Space-based observations that can be correlated to observations over a ground-based site are possible for only a few minutes per day. Ground-based observations can be complemented by space-based observations only by experiments operating in snapshot mode and using a high-performance instrumentation during the limited flight time over a ground station. The only space platform currently capable of supporting such experimentation is the space shuttle, or Space Transportation System (STS). In the future, appropriate payloads should be planned and deployed on the International Space Station to take advantage of its similar capabilities. The night airglow layer at the Earth's limb was monitored by the Arizona Airglow Experiment (GLO) from the space shuttle Endeavour throughout its 12-day STS 69 mission in September 1995. When the nightglow was observed from above, the O2 atmospheric band system was conspicuous. Patches of enhanced emission 2500-5000 km in lateral extent were observed. Intensity changes by a factor of 4 were common. Similar activity has been reported in data from the Upper Atmosphere Research Satellite (UARS) remote sensing experiments high-resolution Doppler imager (HRDI) and wind imaging inferometer (WINDII). The O2(0,0) band emission cannot be observed from the ground because the intervening O2 atmosphere overhead is optically thick to this emission. However, the O2

  4. The WASP and NGTS ground-based transit surveys

    NASA Astrophysics Data System (ADS)

    Wheatley, P. J.

    2015-10-01

    I will review the current status of ground-based exoplanet transit surveys, using the Wide Angle Search for Planets (WASP) and the Next Generation Transit Survey (NGTS) as specific examples. I will describe the methods employed by these surveys and show how planets from Neptune to Jupiter-size are detected and confirmed around bright stars. I will also give an overview of the remarkably wide range of exoplanet characterization that is made possible with large-telescope follow up of these bright transiting systems. This characterization includes bulk composition and spin-orbit alignment, as well as atmospheric properties such as thermal structure, composition and dynamics. Finally, I will outline how ground-based photometric studies of transiting planets will evolve with the advent of new space-based surveys such as TESS and PLATO.

  5. Ground-based Nuclear Detonation Detection (GNDD) Technology Roadmap

    SciTech Connect

    Casey, Leslie A.

    2014-01-13

    This GNDD Technology Roadmap is intended to provide guidance to potential researchers and help management define research priorities to achieve technology advancements for ground-based nuclear explosion monitoring science being pursued by the Ground-based Nuclear Detonation Detection (GNDD) Team within the Office of Nuclear Detonation Detection in the National Nuclear Security Administration (NNSA) of the U.S. Department of Energy (DOE). Four science-based elements were selected to encompass the entire scope of nuclear monitoring research and development (R&D) necessary to facilitate breakthrough scientific results, as well as deliver impactful products. Promising future R&D is delineated including dual use associated with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Important research themes as well as associated metrics are identified along with a progression of accomplishments, represented by a selected bibliography, that are precursors to major improvements to nuclear explosion monitoring.

  6. Rainfall Measurement with a Ground Based Dual Frequency Radar

    NASA Technical Reports Server (NTRS)

    Takahashi, Nobuhiro; Horie, Hiroaki; Meneghini, Robert

    1997-01-01

    Dual frequency methods are one of the most useful ways to estimate precise rainfall rates. However, there are some difficulties in applying this method to ground based radars because of the existence of a blind zone and possible error in the radar calibration. Because of these problems, supplemental observations such as rain gauges or satellite link estimates of path integrated attenuation (PIA) are needed. This study shows how to estimate rainfall rate with a ground based dual frequency radar with rain gauge and satellite link data. Applications of this method to stratiform rainfall is also shown. This method is compared with single wavelength method. Data were obtained from a dual frequency (10 GHz and 35 GHz) multiparameter radar radiometer built by the Communications Research Laboratory (CRL), Japan, and located at NASA/GSFC during the spring of 1997. Optical rain gauge (ORG) data and broadcasting satellite signal data near the radar t location were also utilized for the calculation.

  7. Rainfall Measurement with a Ground Based Dual Frequency Radar

    NASA Technical Reports Server (NTRS)

    Takahashi, Nobuhiro; Horie, Hiroaki; Meneghini, Robert

    1997-01-01

    Dual frequency methods are one of the most useful ways to estimate precise rainfall rates. However, there are some difficulties in applying this method to ground based radars because of the existence of a blind zone and possible error in the radar calibration. Because of these problems, supplemental observations such as rain gauges or satellite link estimates of path integrated attenuation (PIA) are needed. This study shows how to estimate rainfall rate with a ground based dual frequency radar with rain gauge and satellite link data. Applications of this method to stratiform rainfall is also shown. This method is compared with single wavelength method. Data were obtained from a dual frequency (10 GHz and 35 GHz) multiparameter radar radiometer built by the Communications Research Laboratory (CRL), Japan, and located at NASA/GSFC during the spring of 1997. Optical rain gauge (ORG) data and broadcasting satellite signal data near the radar t location were also utilized for the calculation.

  8. Coordinated Ground-Based and AIM Satellite Measurements of Mesospheric and Stratospheric Waves over South America

    NASA Astrophysics Data System (ADS)

    Taylor, M. J.; Zhao, Y.; Pautet, P. D.; Carstens, J. N.; Pugmire, J. R.; Smith, S. M.; Liu, A. Z.; Vargas, F.; Swenson, G. R.; Randall, C. E.; Bailey, S. M.; Russell, J. M., III

    2016-12-01

    To date, the primary research goals of the Aeronomy of Ice in the Mesosphere (AIM) satellite have focussed on investigating the occurrence, properties and dynamics of high-latitude Polar Mesospheric Clouds (PMC). With the evolution of the AIM orbit beta angle the opportunity now exists to make measurements outside the PMC region covering mid-low and equatorial latitudes. As part of the extended AIM mission science program, the AIM platform in conjunction with auxiliary ground-based measurements will be used to better understand upper atmospheric dynamics and vertical coupling due to gravity waves. Over the next 2 years AIM will take advantage of a new imaging capability of the on-board large-field CIPS UV imager to capture new data on the characteristics and spatial extents of stratospheric gravity waves near the 50 km level and their variation with latitude and season. In this study we report on initial coordinated ground-based measurements with the Andes Lidar Observatory (ALO) at Cerro Pachon, Chile ( 30°S) and nearby El Leoncito Observatory, Argentina, high in the Andes Mountains, where regular remote-sensing measurements are made using meteor radar, mesospheric airglow imagers, temperature mappers and an Na wind-temperature lidar (on a campaign basis). First coordinated measurements were made during the winter period in June 2016. AIM daytime overpasses have been analysed to search for and characterize extensive stratospheric wave events, as well as long-lived "Mountain Waves" over South America. Subsequent night-time ground-based measurements have been used to quantify wave characteristics in the mesopause region ( 80-100 km) to investigate vertical coupling. These measurements are continuing and it is planned to extend the new AIM stratospheric gravity wave data set for similar studies from a number of well-instrumented ground sites around the world.

  9. Ground-Based Calibration Of A Microwave Landing System

    NASA Technical Reports Server (NTRS)

    Kiriazes, John J.; Scott, Marshall M., Jr.; Willis, Alfred D.; Erdogan, Temel; Reyes, Rolando

    1996-01-01

    System of microwave instrumentation and data-processing equipment developed to enable ground-based calibration of microwave scanning-beam landing system (MSBLS) at distances of about 500 to 1,000 ft from MSBLS transmitting antenna. Ensures accuracy of MSBLS near touchdown point, without having to resort to expense and complex logistics of aircraft-based testing. Modified versions prove useful in calibrating aircraft instrument landing systems.

  10. The Validation of Ground Based Ozone Measurements over Korea.

    NASA Astrophysics Data System (ADS)

    Baek, K. H.; Kim, J. H.; Herman, J. R.; Haffner, D. P.; Kim, J.

    2015-12-01

    The Validation of Ground Based Ozone Measurements over KoreaKorea will launch GEMS instrument in 2018 onboard the Geostationary Korea Multi-Purpose Satellite to monitor tropospheric gas concentrations in both high temporal and spatial resolution. In order to utilize information from satellite, it is crucial to carry out validation of satellite data with respect to ground-based measurements because satellite retrievals suffer from large error. The purpose of this study is to examine the performance of total ozone measurements from Pandora, Brewer, and Dobson which will be used for validation of GEMS ozone product. Because single version of the satellite retrieval algorithm is used to process the entire data set for a given satellite instrument and satellite instrument characteristics are typically changing slowly, it is assumed that sudden jumps or large drifts in ground-satellite total ozone measurements difference for individual sites are commonly related to problems with ground-based measurements. Thereby, satellite measurements can be used to estimate the performance of the ground-based measurement network as well as to identify potential problems residing in individual station. As a reference of satellite ozone measurements, we have selected ozone data derived from OMI-TOMS V8.5 algorithm because it is a very robust algorithm that has well studied about various error sources such as the effects of aerosols and clouds, variation in shape of ozone profiles with season, latitude, and total ozone. For the future validation of GEMS measurements, Korea has planned to use Pandora measurement that has been started operating since 2012. However, Pandora measurements reported to have unusual high total column ozone in the presence of clouds from the comparison of Pandora with OMI total ozone during DISCOVERY-AQ campaign. In this study, we will analyze the Pandora measurements associated with cloud and introduce the statistical technique, Kalman Filter, to correct the

  11. Ground-based lidar for atmospheric boundary layer ozone measurements.

    PubMed

    Kuang, Shi; Newchurch, Michael J; Burris, John; Liu, Xiong

    2013-05-20

    Ground-based lidars are suitable for long-term ozone monitoring as a complement to satellite and ozonesonde measurements. However, current ground-based lidars are unable to consistently measure ozone below 500 m above ground level (AGL) due to both engineering issues and high retrieval sensitivity to various measurement errors. In this paper, we present our instrument design, retrieval techniques, and preliminary results that focus on the high-temporal profiling of ozone within the atmospheric boundary layer (ABL) achieved by the addition of an inexpensive and compact mini-receiver to the previous system. For the first time, to the best of our knowledge, the lowest, consistently achievable observation height has been extended down to 125 m AGL for a ground-based ozone lidar system. Both the analysis and preliminary measurements demonstrate that this lidar measures ozone with a precision generally better than ±10% at a temporal resolution of 10 min and a vertical resolution from 150 m at the bottom of the ABL to 550 m at the top. A measurement example from summertime shows that inhomogeneous ozone aloft was affected by both surface emissions and the evolution of ABL structures.

  12. Ground-Based Lidar for Atmospheric Boundary Layer Ozone Measurements

    NASA Technical Reports Server (NTRS)

    Kuang, Shi; Newchurch, Michael J.; Burris, John; Liu, Xiong

    2013-01-01

    Ground-based lidars are suitable for long-term ozone monitoring as a complement to satellite and ozonesonde measurements. However, current ground-based lidars are unable to consistently measure ozone below 500 m above ground level (AGL) due to both engineering issues and high retrieval sensitivity to various measurement errors. In this paper, we present our instrument design, retrieval techniques, and preliminary results that focus on the high-temporal profiling of ozone within the atmospheric boundary layer (ABL) achieved by the addition of an inexpensive and compact mini-receiver to the previous system. For the first time, to the best of our knowledge, the lowest, consistently achievable observation height has been extended down to 125 m AGL for a ground-based ozone lidar system. Both the analysis and preliminary measurements demonstrate that this lidar measures ozone with a precision generally better than 10% at a temporal resolution of 10 min and a vertical resolution from 150 m at the bottom of the ABL to 550 m at the top. A measurement example from summertime shows that inhomogeneous ozone aloft was affected by both surface emissions and the evolution of ABL structures.

  13. Ground-Based Correlates of Solar Irradiance Variation

    NASA Technical Reports Server (NTRS)

    Jones, Harrison P.

    2001-01-01

    Ground-based instruments cannot directly measure solar irradiance variability at the 0.1% level at which it occurs because of the earth's atmosphere. However, many forms of ground-based solar observations correlate well with solar irradiance variations, and this fact has been used to construct facular-sunspot models which can explain about 90% of the variance of total solar irradiance as observed by spacecraft radiometers. It is not yet clear whether remaining discrepancies are observational or require additional sources in the model. This paper is a selective review of the current status of the use of ground-based data to understand spacecraft observations of solar irradiance and to apply this understanding to periods before space-based measurements were available. New results from the extension of the histogram analysis of NASA/NSO spectromagnetograph observations (Jones et al., 2000, ApJ529, 1070) to the period from Nov. 1992 to Sep. 2000 are reported which confirm that strong mixed polarity magnetic regions (quiet network) are not significantly correlated with total solar irradiance and which show an unexplained linear trend in the residuals of a multiple regression.

  14. Concepts for on-board satellite image registration. Volume 2: IAS prototype performance evaluation standard definition. [NEEDS Information Adaptive System

    NASA Technical Reports Server (NTRS)

    Daluge, D. R.; Ruedger, W. H.

    1981-01-01

    Problems encountered in testing onboard signal processing hardware designed to achieve radiometric and geometric correction of satellite imaging data are considered. These include obtaining representative image and ancillary data for simulation and the transfer and storage of a large quantity of image data at very high speed. The high resolution, high speed preprocessing of LANDSAT-D imagery is considered.

  15. Rapid Prototyping

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Javelin, a Lone Peak Engineering Inc. Company has introduced the SteamRoller(TM) System as a commercial product. The system was designed by Javelin during a Phase II NASA funded small commercial product. The purpose of the invention was to allow automated-feed of flexible ceramic tapes to the Laminated Object Manufacturing rapid prototyping equipment. The ceramic material that Javelin was working with during the Phase II project is silicon nitride. This engineered ceramic material is of interest for space-based component.

  16. Electronic prototyping

    NASA Technical Reports Server (NTRS)

    Hopcroft, J.

    1987-01-01

    The potential benefits of automation in space are significant. The science base needed to support this automation not only will help control costs and reduce lead-time in the earth-based design and construction of space stations, but also will advance the nation's capability for computer design, simulation, testing, and debugging of sophisticated objects electronically. Progress in automation will require the ability to electronically represent, reason about, and manipulate objects. Discussed here is the development of representations, languages, editors, and model-driven simulation systems to support electronic prototyping. In particular, it identifies areas where basic research is needed before further progress can be made.

  17. Micro insert: a prototype full-ring PET device for improving the image resolution of a small-animal PET scanner.

    PubMed

    Wu, Heyu; Pal, Debashish; Song, Tae Yong; O'Sullivan, Joseph A; Tai, Yuan-Chuan

    2008-10-01

    A full-ring PET insert device should be able to enhance the image resolution of existing small-animal PET scanners. The device consists of 18 high-resolution PET detectors in a cylindric enclosure. Each detector contains a cerium-doped lutetium oxyorthosilicate array (12 x 12 crystals, 0.72 x 1.51 x 3.75 mm each) coupled to a position-sensitive photomultiplier tube via an optical fiber bundle made of 8 x 16 square multiclad fibers. Signals from the insert detectors are connected to the scanner through the electronics of the disabled first ring of detectors, which permits coincidence detection between the 2 systems. Energy resolution of a detector was measured using a (68)Ge point source, and a calibrated (68)Ge point source stepped across the axial field of view (FOV) provided the sensitivity profile of the system. A (22)Na point source imaged at different offsets from the center characterized the in-plane resolution of the insert system. Imaging was then performed with a Derenzo phantom filled with 19.5 MBq of (18)F-fluoride and imaged for 2 h; a 24.3-g mouse injected with 129.5 MBq of (18)F-fluoride and imaged in 5 bed positions at 3.5 h after injection; and a 22.8-g mouse injected with 14.3 MBq of (18)F-FDG and imaged for 2 h with electrocardiogram gating. The energy resolution of a typical detector module at 511 keV is 19.0% +/- 3.1%. The peak sensitivity of the system is approximately 2.67%. The image resolution of the system ranges from 1.0- to 1.8-mm full width at half maximum near the center of the FOV, depending on the type of coincidence events used for image reconstruction. Derenzo phantom and mouse bone images showed significant improvement in transaxial image resolution using the insert device. Mouse heart images demonstrated the gated imaging capability of the device. We have built a prototype full-ring insert device for a small-animal PET scanner to provide higher-resolution PET images within a reduced imaging FOV. Development of additional

  18. Utility of a prototype liposomal contrast agent for x-ray imaging of breast cancer: a proof of concept using micro-CT in small animals

    NASA Astrophysics Data System (ADS)

    Badea, C. T.; Samei, E.; Ghaghada, K.; Saunders, R.; Yuan, H.; Qi, Y.; Hedlund, L. W.; Mukundan, S.

    2008-03-01

    Imaging tumor angiogenesis in small animals is extremely challenging due to the size of the tumor vessels. Consequently, both dedicated small animal imaging systems and specialized intravascular contrast agents are required. The goal of this study was to investigate the use of a liposomal contrast agent for high-resolution micro-CT imaging of breast tumors in small animals. A liposomal blood pool agent encapsulating iodine with a concentration of 65.5 mg/ml was used with a Duke Center for In Vivo Microscopy (CIVM) prototype micro-computed tomography (micro-CT) system to image the R3230AC mammary carcinoma implanted in rats. The animals were injected with equivalent volume doses (0.02 ml/kg) of contrast agent. Micro-CT with the liposomal blood pool contrast agent ensured a signal difference between the blood and the muscle higher than 450 HU allowing the visualization of the tumors 3D vascular architecture in exquisite detail at 100-micron resolution. The micro-CT data correlated well with the histological examination of tumor tissue. We also studied the ability to detect vascular enhancement with limited angle based reconstruction, i.e. tomosynthesis. Tumor volumes and their regional vascular percentage were estimated. This imaging approach could be used to better understand tumor angiogenesis and be the basis for evaluating anti-angiogenic therapies.

  19. A prototype hand-held tri-modal instrument for in vivo ultrasound, photoacoustic, and fluorescence imaging.

    PubMed

    Kang, Jeeun; Chang, Jin Ho; Wilson, Brian C; Veilleux, Israel; Bai, Yanhui; DaCosta, Ralph; Kim, Kang; Ha, Seunghan; Lee, Jong Gun; Kim, Jeong Seok; Lee, Sang-Goo; Kim, Sun Mi; Lee, Hak Jong; Ahn, Young Bok; Han, Seunghee; Yoo, Yangmo; Song, Tai-Kyong

    2015-03-01

    Multi-modality imaging is beneficial for both preclinical and clinical applications as it enables complementary information from each modality to be obtained in a single procedure. In this paper, we report the design, fabrication, and testing of a novel tri-modal in vivo imaging system to exploit molecular/functional information from fluorescence (FL) and photoacoustic (PA) imaging as well as anatomical information from ultrasound (US) imaging. The same ultrasound transducer was used for both US and PA imaging, bringing the pulsed laser light into a compact probe by fiberoptic bundles. The FL subsystem is independent of the acoustic components but the front end that delivers and collects the light is physically integrated into the same probe. The tri-modal imaging system was implemented to provide each modality image in real time as well as co-registration of the images. The performance of the system was evaluated through phantom and in vivo animal experiments. The results demonstrate that combining the modalities does not significantly compromise the performance of each of the separate US, PA, and FL imaging techniques, while enabling multi-modality registration. The potential applications of this novel approach to multi-modality imaging range from preclinical research to clinical diagnosis, especially in detection/localization and surgical guidance of accessible solid tumors.

  20. A prototype hand-held tri-modal instrument for in vivo ultrasound, photoacoustic, and fluorescence imaging

    NASA Astrophysics Data System (ADS)

    Kang, Jeeun; Chang, Jin Ho; Wilson, Brian C.; Veilleux, Israel; Bai, Yanhui; DaCosta, Ralph; Kim, Kang; Ha, Seunghan; Lee, Jong Gun; Kim, Jeong Seok; Lee, Sang-Goo; Kim, Sun Mi; Lee, Hak Jong; Ahn, Young Bok; Han, Seunghee; Yoo, Yangmo; Song, Tai-Kyong

    2015-03-01

    Multi-modality imaging is beneficial for both preclinical and clinical applications as it enables complementary information from each modality to be obtained in a single procedure. In this paper, we report the design, fabrication, and testing of a novel tri-modal in vivo imaging system to exploit molecular/functional information from fluorescence (FL) and photoacoustic (PA) imaging as well as anatomical information from ultrasound (US) imaging. The same ultrasound transducer was used for both US and PA imaging, bringing the pulsed laser light into a compact probe by fiberoptic bundles. The FL subsystem is independent of the acoustic components but the front end that delivers and collects the light is physically integrated into the same probe. The tri-modal imaging system was implemented to provide each modality image in real time as well as co-registration of the images. The performance of the system was evaluated through phantom and in vivo animal experiments. The results demonstrate that combining the modalities does not significantly compromise the performance of each of the separate US, PA, and FL imaging techniques, while enabling multi-modality registration. The potential applications of this novel approach to multi-modality imaging range from preclinical research to clinical diagnosis, especially in detection/localization and surgical guidance of accessible solid tumors.

  1. Atmospheric turbulence and the resolution limits of large ground-based telescopes: Reply to comment

    SciTech Connect

    McKechnie, T.S.

    1993-11-01

    The highly resolved star images obtained with the 4-m Kitt Peak telescope have eluded explanation by conventional theory and yet are quite consistent with alternative predictions based on a smaller value of L{sub o}. Tatarskii and Zavorotny claim that conventional theory also can predict the images, but one notes that they do not actually give specific predictions to support their claim. Based on a mistaken assumption about the magnitude of rms wave-height variations, they conclude that there is no difference between a core and a bright speckle. Thus they may not recognize the enormous significance of cores to L{sub o} ground-based tracking and imaging at infrared wavelengths. 13 refs.

  2. Laser Doppler imaging of cutaneous blood flow through transparent face masks: a necessary preamble to computer-controlled rapid prototyping fabrication with submillimeter precision.

    PubMed

    Allely, Rebekah R; Van-Buendia, Lan B; Jeng, James C; White, Patricia; Wu, Jingshu; Niszczak, Jonathan; Jordan, Marion H

    2008-01-01

    A paradigm shift in management of postburn facial scarring is lurking "just beneath the waves" with the widespread availability of two recent technologies: precise three-dimensional scanning/digitizing of complex surfaces and computer-controlled rapid prototyping three-dimensional "printers". Laser Doppler imaging may be the sensible method to track the scar hyperemia that should form the basis of assessing progress and directing incremental changes in the digitized topographical face mask "prescription". The purpose of this study was to establish feasibility of detecting perfusion through transparent face masks using the Laser Doppler Imaging scanner. Laser Doppler images of perfusion were obtained at multiple facial regions on five uninjured staff members. Images were obtained without a mask, followed by images with a loose fitting mask with and without a silicone liner, and then with a tight fitting mask with and without a silicone liner. Right and left oblique images, in addition to the frontal images, were used to overcome unobtainable measurements at the extremes of face mask curvature. General linear model, mixed model, and t tests were used for data analysis. Three hundred seventy-five measurements were used for analysis, with a mean perfusion unit of 299 and pixel validity of 97%. The effect of face mask pressure with and without the silicone liner was readily quantified with significant changes in mean cutaneous blood flow (P < .5). High valid pixel rate laser Doppler imager flow data can be obtained through transparent face masks. Perfusion decreases with the application of pressure and with silicone. Every participant measured differently in perfusion units; however, consistent perfusion patterns in the face were observed.

  3. Ground-based observations of 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Snodgrass, C.

    2015-10-01

    I will described the campaign of observations from ground-based (and Earth orbiting) telescopes that supports the Rosetta mission. Rosetta gets closer to the nucleus than any previous mission, and returns wonderfully detailed measurements from the heart of the comet, but at the cost of not seeing the large scale coma and tails. The ground-based campaign fills in the missing part of the picture, studying the comet at #1000km resolution, and following how the overall activity of the comet varies. These data provide context information for Rosetta, so changes in the inner coma seen by the spacecraft can be correlated with the phenomena observable in comets. This not only helps to complete our understanding of the activity of 67P, but also allows us to compare it with other comets that are only observed from the ground, and in that way extend the results of the Rosetta mission to the wider population. The ground-based campaign includes observations with nearly all major facilities world-wide. In 2014 the majority of data came from the ESO VLT, as the comet was still relatively faint and in Southern skies, but as it returns to visibility from Earth in 2015 it will be considerably brighter, approaching its perihelion in August, and at Northern declinations. I will show results from the 2014 campaign, including visible wavelength photometry and spectroscopy, and the latest results from early 2015 observations. I will also describe the varied observations that will be included in the campaign post-perihelion, and how all of these results fit around what we are learning about 67P from Rosetta.

  4. Space and ground-based GNSS activities at NOAA

    NASA Astrophysics Data System (ADS)

    Cucurull, L.

    2016-12-01

    With the launch of the FORMOSAT-3/COSMIC satellites in April 2006, the availability of Global Navigation Satellite Systems (GNSS) Radio Occultation (RO) observations for operational Numerical Weather Prediction (NWP) applications began. GNSS RO profiles started being assimilated operationally in the major worldwide weather centers soon after. NOAA started assimilating RO data operationally in early 2007. After COSMIC, other missions carrying GNSS RO receivers became available for operational uses. The incorporation of RO observations into the operational assimilation systems was shown to improve global model forecast skill. Since its launch in 2006, the COSMIC constellation has been the mainstay of the global RO system. However, COSMIC is already past the end of its formal lifetime, and only three satellites are still operating. This has motivated NOAA to invest on the COSMIC-2 mission, a 12-satellite constellation, that will replace COSMIC. The first launch, in equatorial orbit, is planned for March 2017. In addition to the space-based component of the GNSS technique, NOAA is assimilating ground-based products into its operational regional models. Although most stations over CONUS provide estimates of Precipitable Water (PW), this is not the case outside the U.S., where the required auxiliary meteorological information is generally not available. Thus, in order to evaluate the impact of ground-based GNSS products on a global weather model, the assimilation of less derived products, such as zenith total delays, rather than PW, is necessary. The talk will include an update on current activities and future plans for the utilization of space and ground-based GNSS products at NOAA. In addition, an update on the COSMIC-2 mission will be discussed.

  5. The GROUnd-based Secondary Eclipse project - GROUSE

    NASA Astrophysics Data System (ADS)

    de Mooij, Ernst; de Kok, Remco; Nefs, Bas; Brogi, Matteo; Snellen, Ignas

    2011-11-01

    Secondary eclipse observations of exoplanets at near-infrared wavelengths are important to constrain the energy budgets of hot-Jupiters, since they probe the radiation from the planet's atmosphere at the peak of the spectral energy distribution. Since this wavelength range is accesible from the ground, we have started the GROUnd-based Secondary Eclipse (GROUSE) project. As part of the GROUSE project, we target a sample of hot-Jupiters at near-infrared and optical wavelengths. Planets include TrES-3b, HAT-P-1, WASP-18b and WASP-33b.

  6. Sky type discrimination using a ground-based sun photometer

    USGS Publications Warehouse

    DeFelice, Thomas P.; Wylie, Bruce K.

    2001-01-01

    A 2-year feasibility study was conducted at the USGS EROS Data Center, South Dakota (43.733°N, 96.6167°W) to assess whether a four-band, ground-based, sun photometer could be used to discriminate sky types. The results indicate that unique spectral signatures do exist between sunny skies (including clear and hazy skies) and cirrus, and cirrostratus, altocumulus or fair-weather cumulus, and thin stratocumulus or altostratus, and fog/fractostratus skies. There were insufficient data points to represent other cloud types at a statistically significant level.

  7. Research on target accuracy for ground-based lidar

    NASA Astrophysics Data System (ADS)

    Zhu, Ling; Shi, Ruoming

    2009-05-01

    In ground based Lidar system, the targets are used in the process of registration, georeferencing for point cloud, and also can be used as check points. Generally, the accuracy of capturing the flat target center is influenced by scanning range and scanning angle. In this research, the experiments are designed to extract accuracy index of the target center with 0-90°scan angles and 100-195 meter scan ranges using a Leica HDS3000 laser scanner. The data of the experiments are listed in detail and the related results are analyzed.

  8. High-resolution Ground-based European Solar Physics

    NASA Astrophysics Data System (ADS)

    Collados, M.

    2008-12-01

    This communication reviews some of the most challenging topics in high-resolution ground-based Solar Physics. The most powerful European facilities are described, together with their capabilities and skills gained in Europe using them. The reasons for a large-aperture solar telescope are outlined, based on present scientific needs, which have led to the joint project EST (European Solar Telescope), in which the most prestigious European Solar Physics research institutions participate. Some technical challenges of a such a large telescope are mentioned.

  9. Microgravity research in NASA ground-based facilities

    NASA Technical Reports Server (NTRS)

    Lekan, Jack

    1989-01-01

    An overview of reduced gravity research performed in NASA ground-based facilities sponsored by the Microgravity Science and Applications Program of the NASA Office of Space Science and Applications is presented. A brief description and summary of the operations and capabilities of each of these facilities along with an overview of the historical usage of them is included. The goals and program elements of the Microgravity Science and Applications programs are described and the specific programs that utilize the low gravity facilities are identified. Results from two particular investigations in combustion (flame spread over solid fuels) and fluid physics (gas-liquid flows at microgravity conditions) are presented.

  10. Flight- and Ground-Based Materials Science Programs at NASA

    NASA Technical Reports Server (NTRS)

    Gillies, Donald C.

    1999-01-01

    The Microgravity Research Division of NASA funds research programs in all branches of materials science including ceramics and glasses. A NASA Research Announcement (NRA)is currently planned with proposals due in March 1999. Proposals are accepted for both flight- definition and ground- based research projects with a main criterion being a strong justification for microgravity. A review of the program in its entirety will be given, with special emphasis on microgravity related ceramics research. The topics of current interest in the NRA will be discussed in terms of International Space Station research and NASA's Human Exploration and Development of Space (HEDS) initiative.

  11. Ground-based observations and AD HOC models

    NASA Astrophysics Data System (ADS)

    Ground based observations of B stars in the visible, the infrared, and the radio region are described along with the ad hoc models proposed to interpret them. It is shown that these observations refer essentially to the photosphere and to the regions of the outer atmosphere where the gas is cool and at low velocity. The characteristics of the variability of the continuous and line spectrum are examined in general and in the cases of individual stars. Finally, linear polarization in the B stars is discussed.

  12. Recent Improvements in AMSR2 Ground-Based RFI Filtering

    NASA Astrophysics Data System (ADS)

    Scott, J. P.; Gentemann, C. L.; Wentz, F. J.

    2015-12-01

    Passive satellite radiometer measurements in the microwave frequencies (6-89 GHz) are useful in providing geophysical retrievals of sea surface temperature (SST), atmospheric water vapor, wind speed, rain rate, and more. However, radio frequency interference (RFI) is one of the fastest growing sources of error in these retrievals. RFI can originate from broadcasting satellites, as well as from ground-based instrumentation that makes use of the microwave range. The microwave channel bandwidths used by passive satellite radiometers are often wider than the protected bands allocated for this type of remote sensing, a common practice in microwave radiometer design used to reduce the effect of instrument noise in the observed signal. However, broad channel bandwidths allow greater opportunity for RFI to affect these observations and retrievals. For ground-based RFI, a signal is broadcast directly into the atmosphere which may interfere with the radiometer - its antenna, cold mirror, hot load or the internal workings of the radiometer itself. It is relatively easy to identify and flag RFI from large sources, but more difficult to do so from small, sporadic sources. Ground-based RFI has high spatial and temporal variability, requiring constant, automated detection and removal to avoid spurious trends leaching into the geophysical retrievals. Ascension Island in the South Atlantic Ocean has been one of these notorious ground-based RFI sources, affecting many microwave radiometers, including the AMSR2 radiometer onboard JAXA's GCOM-W1 satellite. Ascension Island RFI mainly affects AMSR2's lower frequency channels (6.9, 7.3, and 10.65 GHz) over a broad spatial region in the South Atlantic Ocean, which makes it challenging to detect and flag this RFI using conventional channel and geophysical retrieval differencing techniques. The authors have developed a new method of using the radiometer's earth counts and hot counts, for the affected channels, to detect an Ascension Island

  13. Comparison of Satellite and Ground-based Measurements of Polar Mesospheric Clouds

    NASA Astrophysics Data System (ADS)

    Barker-Tvedtnes, J.; Taylor, M.; Deland, M.

    2008-12-01

    Polar Mesospheric Clouds (PMCs) are tenuous ice clouds that form near the cold (<150K) summer mesopause region (80-85 km). From the ground, these clouds are seen during twilight hours as Noctilucent or "night shining" Clouds (NLCs) and are typically seen from latitudes from 50° to 65°. Observations by the Solar Backscatter Ultraviolet (SBUV) instruments on the NOAA satellites have shown that the occurrence and brightness of NLCs have been increasing over the last several decades prompting speculation concerning their possible role in climate change. Recently the Aeronomy of Ice in the Mesosphere (AIM) satellite was launched (April 2007) and is the first satellite dedicated to the study of NLCs. In this presentation, we compare SBUV and AIM PMC observations with ground-based image data collected during two campaigns from Edmonton, Canada (June 30-July 17, 2007) and Delta Junction, Alaska (July 29- August 17, 2007). Four nights of data are presented where coincident measurements were obtained by AIM, SBUV and ground-based imagers. The results show good spatial or temporal agreement, but rarely both, and illustrate the importance of coordinated measurements for better understanding the geographic and local time variability of PMCs.

  14. Methane Emissions from Bangladesh: Bridging the Gap Between Ground-based and Space-borne Estimates

    NASA Astrophysics Data System (ADS)

    Peters, C.; Bennartz, R.; Hornberger, G. M.

    2015-12-01

    Gaining an understanding of methane (CH4) emission sources and atmospheric dispersion is an essential part of climate change research. Large-scale and global studies often rely on satellite observations of column CH4 mixing ratio whereas high-spatial resolution estimates rely on ground-based measurements. Extrapolation of ground-based measurements on, for example, rice paddies to broad region scales is highly uncertain because of spatio-temporal variability. We explore the use of ground-based river stage measurements and independent satellite observations of flooded area along with satellite measurements of CH4 mixing ratio to estimate the extent of methane emissions. Bangladesh, which comprises most of the Ganges Brahmaputra Meghna (GBM) delta, is a region of particular interest for studying spatio-temporal variation of methane emissions due to (1) broadscale rice cultivation and (2) seasonal flooding and atmospheric convection during the monsoon. Bangladesh and its deltaic landscape exhibit a broad range of environmental, economic, and social circumstances that are relevant to many nations in South and Southeast Asia. We explore the seasonal enhancement of CH4 in Bangladesh using passive remote sensing spectrometer CH4 products from the SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) and the Atmospheric Infrared Sounder (AIRS). The seasonal variation of CH4 is compared to independent estimates of seasonal flooding from water gauge stations and space-based passive microwave water-to-land fractions from the Tropical Rainfall Measuring Mission Microwave Imager (TRMM-TMI). Annual cycles in inundation (natural and anthropogenic) and atmospheric CH4 concentrations show highly correlated seasonal signals. NOAA's HYSPLIT model is used to determine atmospheric residence time of ground CH4 fluxes. Using the satellite observations, we can narrow the large uncertainty in extrapolation of ground-based CH4 emission estimates from rice paddies

  15. Research into a Single-aperture Light Field Camera System to Obtain Passive Ground-based 3D Imagery of LEO Objects

    NASA Astrophysics Data System (ADS)

    Bechis, K.; Pitruzzello, A.

    2014-09-01

    This presentation describes our ongoing research into using a ground-based light field camera to obtain passive, single-aperture 3D imagery of LEO objects. Light field cameras are an emerging and rapidly evolving technology for passive 3D imaging with a single optical sensor. The cameras use an array of lenslets placed in front of the camera focal plane, which provides angle of arrival information for light rays originating from across the target, allowing range to target and 3D image to be obtained from a single image using monocular optics. The technology, which has been commercially available for less than four years, has the potential to replace dual-sensor systems such as stereo cameras, dual radar-optical systems, and optical-LIDAR fused systems, thus reducing size, weight, cost, and complexity. We have developed a prototype system for passive ranging and 3D imaging using a commercial light field camera and custom light field image processing algorithms. Our light field camera system has been demonstrated for ground-target surveillance and threat detection applications, and this paper presents results of our research thus far into applying this technology to the 3D imaging of LEO objects. The prototype 3D imaging camera system developed by Northrop Grumman uses a Raytrix R5 C2GigE light field camera connected to a Windows computer with an nVidia graphics processing unit (GPU). The system has a frame rate of 30 Hz, and a software control interface allows for automated camera triggering and light field image acquisition to disk. Custom image processing software then performs the following steps: (1) image refocusing, (2) change detection, (3) range finding, and (4) 3D reconstruction. In Step (1), a series of 2D images are generated from each light field image; the 2D images can be refocused at up to 100 different depths. Currently, steps (1) through (3) are automated, while step (4) requires some user interaction. A key requirement for light field camera

  16. Automated cloud classification using a ground based infra-red camera and texture analysis techniques

    NASA Astrophysics Data System (ADS)

    Rumi, Emal; Kerr, David; Coupland, Jeremy M.; Sandford, Andrew P.; Brettle, Mike J.

    2013-10-01

    Clouds play an important role in influencing the dynamics of local and global weather and climate conditions. Continuous monitoring of clouds is vital for weather forecasting and for air-traffic control. Convective clouds such as Towering Cumulus (TCU) and Cumulonimbus clouds (CB) are associated with thunderstorms, turbulence and atmospheric instability. Human observers periodically report the presence of CB and TCU clouds during operational hours at airports and observatories; however such observations are expensive and time limited. Robust, automatic classification of cloud type using infrared ground-based instrumentation offers the advantage of continuous, real-time (24/7) data capture and the representation of cloud structure in the form of a thermal map, which can greatly help to characterise certain cloud formations. The work presented here utilised a ground based infrared (8-14 μm) imaging device mounted on a pan/tilt unit for capturing high spatial resolution sky images. These images were processed to extract 45 separate textural features using statistical and spatial frequency based analytical techniques. These features were used to train a weighted k-nearest neighbour (KNN) classifier in order to determine cloud type. Ground truth data were obtained by inspection of images captured simultaneously from a visible wavelength colour camera at the same installation, with approximately the same field of view as the infrared device. These images were classified by a trained cloud observer. Results from the KNN classifier gave an encouraging success rate. A Probability of Detection (POD) of up to 90% with a Probability of False Alarm (POFA) as low as 16% was achieved.

  17. Correlation of satellite lightning observations with ground-based lightning experiments in Florida, Texas and Oklahoma

    NASA Technical Reports Server (NTRS)

    Edgar, B. C.; Turman, B. N.

    1982-01-01

    Satellite observations of lightning were correlated with ground-based measurements of lightning from data bases obtained at three separate sites. The percentage of ground-based observations of lightning that would be seen by an orbiting satellite was determined.

  18. Light pollution simulations for planar ground-based light sources.

    PubMed

    Kocifaj, Miroslav

    2008-02-20

    The light pollution model is employed to analyze spatial behavior of luminance at the night sky under cloudless and overcast conditions. Enhanced light excess is particularly identified at cloudy skies, because the clouds efficiently contribute to the downward luminous flux. It is evident that size of ground-based light sources can play an important role in the case of overcast sky conditions. Nevertheless, the realistically sized light sources are rarely embedded into light pollution modeling, and rather they are replaced by simple point sources. We discuss the discrepancies between sky luminance distributions when at first the planar light sources are considered and at second the point-source approximation is accepted. The found differences are noticeable if the size of the light source, distance to the observer, and altitude of a cloudy layer are comparable one to the other. Compared with point-source approximation, an inclusion of the size factor into modeling the light sources leads to partial elimination of the steep changes of sky luminance (typical for point sources of light). The narrow and sharp light pillars normally presented on the sky illuminated by point light sources can disappear or fuse together when two or more nearby light sources are considered with their real sizes. Sky elements situated close to the horizon will glow efficiently if luminous flux originates from two-dimensional ground-based entities (such as cities or villages).

  19. Ground-based observation of near-Earth asteroids

    NASA Technical Reports Server (NTRS)

    Gaffey, Michael J.

    1992-01-01

    An increased ground-based observation program is an essential component of any serious attempt to assess the resource potential of near-Earth asteroids. A vigorous search and characterization program could lead to the discovery and description of about 400 to 500 near-Earth asteroids in the next 20 years. This program, in conjunction with meteorite studies, would provide the data base to ensure that the results of a small number of asteroid-rendezvous and sample-return missions could be extrapolated with confidence into a geological base map of the Aten, Apollo, and Amor asteroids. Ground-based spectral studies of nearly 30 members of the Aten/Apollo/Amor population provide good evidence that this class includes bodies composed of silicates, metal-silicates, and carbonaceous assemblages similar to those found in meteorites. The instruments that are being used or could be used to search for near-Earth asteroids are listed. Techniques useful in characterizing asteroids and the types of information obtainable using these techniques are listed.

  20. Examples of recent ground based L-band radiometer experiments

    NASA Astrophysics Data System (ADS)

    Schwank, Mike; Voelksch, I.; Maetzler, Ch.; Wigneron, Jean-Pierre; Kerr, Y. H.; Antolin, M. C.; Coll, A.; Millan-Scheiding, C.; Lopez-Baeza, Ernesto

    L-band (1 -2 GHz) microwave radiometry is a remote sensing technique to monitor soil mois-ture over land surfaces. The European Space Agency's (ESA) Soil Moisture and Ocean Salinity (SMOS) radiometer mission aims at providing global maps of soil moisture, with accuracy bet-ter than 0.04 m3 m-3 every 3 days, with a spatial resolution of approximately 40 km. Monitoring the large scale moisture dynamics at the boundary between the deep bulk soil and the atmo-sphere provides essential information both for terrestrial and atmospheric modellers. Perform-ing ground based radiometer campaigns before the mission launch, during the commissioning phase and during the operative SMOS mission is important for validating the satellite data and for the further improvement of the used radiative transfer models. This presentation starts with an outline of the basic concepts behind remote moisture retrieval from passive L-band radiation. Then the results from a selection of ground based microwave campaigns performed ü with the ELBARA radiometer and its successor models (JULBARA, ELBARAII) are pre-sented. Furthermore, some of the most important technical features, which were implemented in ELBARAII as the result of the experiences made with the forerunner, are outlined.

  1. MODELING ATMOSPHERIC EMISSION FOR CMB GROUND-BASED OBSERVATIONS

    SciTech Connect

    Errard, J.; Borrill, J.; Ade, P. A. R.; Akiba, Y.; Chinone, Y.; Arnold, K.; Atlas, M.; Barron, D.; Elleflot, T.; Baccigalupi, C.; Fabbian, G.; Boettger, D.; Chapman, S.; Cukierman, A.; Delabrouille, J.; Ducout, A.; Feeney, S.; Feng, C.; and others

    2015-08-10

    Atmosphere is one of the most important noise sources for ground-based cosmic microwave background (CMB) experiments. By increasing optical loading on the detectors, it amplifies their effective noise, while its fluctuations introduce spatial and temporal correlations between detected signals. We present a physically motivated 3D-model of the atmosphere total intensity emission in the millimeter and sub-millimeter wavelengths. We derive a new analytical estimate for the correlation between detectors time-ordered data as a function of the instrument and survey design, as well as several atmospheric parameters such as wind, relative humidity, temperature and turbulence characteristics. Using an original numerical computation, we examine the effect of each physical parameter on the correlations in the time series of a given experiment. We then use a parametric-likelihood approach to validate the modeling and estimate atmosphere parameters from the polarbear-i project first season data set. We derive a new 1.0% upper limit on the linear polarization fraction of atmospheric emission. We also compare our results to previous studies and weather station measurements. The proposed model can be used for realistic simulations of future ground-based CMB observations.

  2. Aerosol Remote Sensing from AERONET, the Ground-Based Satellite

    NASA Technical Reports Server (NTRS)

    Holben, Brent N.

    2012-01-01

    Atmospheric particles including mineral dust, biomass burning smoke, pollution from carbonaceous aerosols and sulfates, sea salt, impact air quality and climate. The Aerosol Robotic Network (AERONET) program, established in the early 1990s, is a federation of ground-based remote sensing aerosol networks of Sun/sky radiometers distributed around the world, which provides a long-term, continuous and readily accessible public domain database of aerosol optical (e.g., aerosol optical depth) and microphysical (e.g., aerosol volume size distribution) properties for aerosol characterization, validation of satellite retrievals, and synergism with Earth science databases. Climatological aerosol properties will be presented at key worldwide locations exhibiting discrete dominant aerosol types. Further, AERONET's temporary mesoscale network campaign (e.g., UAE2, TIGERZ, DRAGON-USA.) results that attempt to quantify spatial and temporal variability of aerosol properties, establish validation of ground-based aerosol retrievals using aircraft profile measurements, and measure aerosol properties on compatible spatial scales with satellite retrievals and aerosol transport models allowing for more robust validation will be discussed.

  3. Ground-based visual inspection for CTBT verification

    SciTech Connect

    Hawkins, W.; Wohletz, K.

    1997-11-01

    Ground-based visual inspection will play an essential role in On-Site Inspection (OSI) for Comprehensive Test Ban Treaty (CTBT) verification. Although seismic and remote sensing techniques are the best understood and most developed methods for detection of evasive testing of nuclear weapons, visual inspection will greatly augment the certainty and detail of understanding provided by these more traditional methods. Not only can ground-based visual inspection offer effective documentation in cases of suspected nuclear testing, but it also can provide accurate source location and testing media properties necessary for detailed analysis of seismic records. For testing in violation of the CTBT, an offending state may attempt to conceal the test, which most likely will be achieved by underground burial. While such concealment may not prevent seismic detection, evidence of test deployment, location, and yield can be disguised. In this light, if a suspicious event is detected by seismic or other remote methods, visual inspection of the event area is necessary to document any evidence that might support a claim of nuclear testing and provide data needed to further interpret seismic records and guide further investigations. However, the methods for visual inspection are not widely known nor appreciated, and experience is presently limited. Visual inspection can be achieved by simple, non-intrusive means, primarily geological in nature, and it is the purpose of this report to describe the considerations, procedures, and equipment required to field such an inspection. The inspections will be carried out by inspectors from members of the CTBT Organization.

  4. Statistical Studies of Ground-Based Optical Lightning Signatures

    NASA Astrophysics Data System (ADS)

    Hunt, C. R.; Nemzek, R. J.; Suszcynsky, D. M.

    2005-12-01

    Most extensive optical studies of lightning have been conducted from orbit, and the statistics of events collected from earth are relatively poorly documented. The time signatures of optical power measured in the presence of clouds are inevitably affected by scattering,which can distort the signatures by extending and delaying the amplitude profile in time. We have deployed two all-sky photodiode detectors, one in New Mexico and one in Oklahoma, which are gathering data alongside electric field change monitors as part of the LANL EDOTX Great Plains Array. Preliminary results show that the photodiode is sensitive to approximately 50% or more of RF events detected at ranges of up to 30 km, and still has some sensitivity at ranges in excess of 60 km (distances determined by the EDOTX field-change array). The shapes of events within this range were assessed, with focus on rise time, width, peak power, and their correlation to corresponding electric field signatures, and these are being compared with published on-orbit and ground-based data. Initial findings suggest a mean characteristic width (ratio of total detected optical energy to peak power) of 291 +/- 12 microseconds and a mean delay between the RF signal peak and optical peak of 121 +/- 17 microseconds. These values fall between prior ground-based measurements of direct return stroke emissions, and scattering-dominated on-orbit measurements. This work will promote better understanding of the correspondence between radio and optical measurements of lightning.

  5. Modeling Atmospheric Emission for CMB Ground-based Observations

    NASA Astrophysics Data System (ADS)

    Errard, J.; Ade, P. A. R.; Akiba, Y.; Arnold, K.; Atlas, M.; Baccigalupi, C.; Barron, D.; Boettger, D.; Borrill, J.; Chapman, S.; Chinone, Y.; Cukierman, A.; Delabrouille, J.; Dobbs, M.; Ducout, A.; Elleflot, T.; Fabbian, G.; Feng, C.; Feeney, S.; Gilbert, A.; Goeckner-Wald, N.; Halverson, N. W.; Hasegawa, M.; Hattori, K.; Hazumi, M.; Hill, C.; Holzapfel, W. L.; Hori, Y.; Inoue, Y.; Jaehnig, G. C.; Jaffe, A. H.; Jeong, O.; Katayama, N.; Kaufman, J.; Keating, B.; Kermish, Z.; Keskitalo, R.; Kisner, T.; Le Jeune, M.; Lee, A. T.; Leitch, E. M.; Leon, D.; Linder, E.; Matsuda, F.; Matsumura, T.; Miller, N. J.; Myers, M. J.; Navaroli, M.; Nishino, H.; Okamura, T.; Paar, H.; Peloton, J.; Poletti, D.; Puglisi, G.; Rebeiz, G.; Reichardt, C. L.; Richards, P. L.; Ross, C.; Rotermund, K. M.; Schenck, D. E.; Sherwin, B. D.; Siritanasak, P.; Smecher, G.; Stebor, N.; Steinbach, B.; Stompor, R.; Suzuki, A.; Tajima, O.; Takakura, S.; Tikhomirov, A.; Tomaru, T.; Whitehorn, N.; Wilson, B.; Yadav, A.; Zahn, O.

    2015-08-01

    Atmosphere is one of the most important noise sources for ground-based cosmic microwave background (CMB) experiments. By increasing optical loading on the detectors, it amplifies their effective noise, while its fluctuations introduce spatial and temporal correlations between detected signals. We present a physically motivated 3D-model of the atmosphere total intensity emission in the millimeter and sub-millimeter wavelengths. We derive a new analytical estimate for the correlation between detectors time-ordered data as a function of the instrument and survey design, as well as several atmospheric parameters such as wind, relative humidity, temperature and turbulence characteristics. Using an original numerical computation, we examine the effect of each physical parameter on the correlations in the time series of a given experiment. We then use a parametric-likelihood approach to validate the modeling and estimate atmosphere parameters from the polarbear-i project first season data set. We derive a new 1.0% upper limit on the linear polarization fraction of atmospheric emission. We also compare our results to previous studies and weather station measurements. The proposed model can be used for realistic simulations of future ground-based CMB observations.

  6. Airborne and Ground-Based Measurements Using a High-Performance Raman Lidar. Part 2; Ground Based

    NASA Technical Reports Server (NTRS)

    Whiteman, David N.; Cadirola, Martin; Venable, Demetrius; Connell, Rasheen; Rush, Kurt; Leblanc, Thierry; McDermid, Stuart

    2009-01-01

    The same RASL hardware as described in part I was installed in a ground-based mobile trailer and used in a water vapor lidar intercomparison campaign, hosted at Table Mountain, CA, under the auspices of the Network for the Detection of Atmospheric Composition Change (NDACC). The converted RASL hardware demonstrated high sensitivity to lower stratospheric water vapor indicating that profiling water vapor at those altitudes with sufficient accuracy to monitor climate change is possible. The measurements from Table Mountain also were used to explain the reason, and correct , for sub-optimal airborne aerosol extinction performance during the flight campaign.

  7. Comparison of the imaging physics performance of a prototype flat-panel detector with a 400-speed screen-film system

    NASA Astrophysics Data System (ADS)

    Huda, Walter; Ogden, Kent M.; Roskopf, Marsha L.; Rush, Charles

    2001-06-01

    The performance of a digital radiography system that included a prototype flat panel detector (StingRay) was compared with a 400 speed screen-film system. The flat panel detector consisted of a 500 micrometers thick CsI scintillator with an image matrix size of 3k2. The limiting spatial resolution of screen-film (approximately 4 line pairs/mm) was superior to that of the flat panel detector (approximately 2.5 line pairs/mm). The digital detector had an excellent linearity response (r2 equals 0.997), a dynamic range of 20,000:1, and saturated at a radiation exposure of 60 mR.

  8. Calibration of AIS Data Using Ground-based Spectral Reflectance Measurements

    NASA Technical Reports Server (NTRS)

    Conel, J. E.

    1985-01-01

    Present methods of correcting airborne imaging spectrometer (AIS) data for instrumental and atmospheric effects include the flat- or curved-field correction and a deviation-from-the-average adjustment performed on a line-by-line basis throughout the image. Both methods eliminate the atmospheric absorptions, but remove the possibility of studying the atmosphere for its own sake, or of using the atmospheric information present as a possible basis for theoretical modeling. The method discussed here relies on use of ground-based measurements of the surface spectral reflectance in comparison with scanner data to fix in a least-squares sense parameters in a simplified model of the atmosphere on a wavelength-by-wavelength basis. The model parameters (for optically thin conditions) are interpretable in terms of optical depth and scattering phase function, and thus, in principle, provide an approximate description of the atmosphere as a homogeneous body intervening between the sensor and the ground.

  9. Data Processing and Analysis Tools Based on Ground-Based Synthetic Aperture Radar Imagery

    NASA Astrophysics Data System (ADS)

    Crosetto, M.; Monserrat, O.; Luzi, G.; Devanthéry, N.; Cuevas-González, M.; Barra, A.

    2017-09-01

    The Ground-Based SAR (GBSAR) is a terrestrial remote sensing technique used to measure and monitor deformation. In this paper we describe two complementary approaches to derive deformation measurements using GBSAR data. The first approach is based on radar interferometry, while the second one exploits the GBSAR amplitude. In this paper we consider the so-called discontinuous GBSAR acquisition mode. The interferometric process is not always straightforward: it requires appropriate data processing and analysis tools. One of the main critical steps is phase unwrapping, which can critically affect the deformation measurements. In this paper we describe the procedure used at the CTTC to process and analyse discontinuous GBSAR data. In the second part of the paper we describe the approach based on GBSAR amplitude images and an image-matching method.

  10. Coordinated Airborne, Spaceborne, and Ground-Based Measurements of Massive, Thick Aerosol Layers During the Dry Season in Southern Africa

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Redemann, J.; Russell, P. B.; Hobbs, P. V.; Hlavka, D. L.; McGill, M. J.; Holben, B. N.; Welton, E. J.; Campbell, J.; Torres, O.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    During the dry-season airborne campaign of the Southern African Regional Science Initiative (SAFARI 2000), unique coordinated observations were made of massive, thick aerosol layers. These layers were often dominated by aerosols from biomass burning. We report on airborne Sunphotometer measurements of aerosol optical depth (lambda=354-1558 nm), columnar water vapor, and vertical profiles of aerosol extinction and water vapor density that were obtained aboard the University of Washington's Convair-580 research aircraft. We compare these with ground-based AERONET Sun/sky radiometer results, with ground based lidar data MPL-Net), and with measurements from a downward-pointing lidar aboard the high-flying NASA ER-2 aircraft. Finally, we show comparisons between aerosol optical depths from the Sunphotometer and those retrieved over land and over water using four spaceborne sensors (TOMS (Total Ozone Mapping Spectrometer), MODIS (Moderate Resolution Imaging Spectrometer), MISR (Multiangle Imaging Spectroradiometer) and ATSR-2 (Along Track Scanning Radiometer)).

  11. A framework for querying a database for structural information on 3D images of macromolecules: A web-based query-by-content prototype on the BioImage macromolecular server.

    PubMed

    de Alarcón, P A; Gupta, A; Carazo, J M

    1999-01-01

    Nowadays we are experiencing a remarkable growth in the number of databases that have become accessible over the Web. However, in a certain number of cases, for example, in the case of BioImage, this information is not of a textual nature, thus posing new challenges in the design of tools to handle these data. In this work, we concentrate on the development of new mechanisms aimed at "querying" these databases of complex data sets by their intrinsic content, rather than by their textual annotations only. We concentrate our efforts on a subset of BioImage containing 3D images (volumes) of biological macromolecules, implementing a first prototype of a "query-by-content" system. In the context of databases of complex data types the term query-by-content makes reference to those data modeling techniques in which user-defined functions aim at "understanding" (to some extent) the informational content of the data sets. In these systems the matching criteria introduced by the user are related to intrinsic features concerning the 3D images themselves, hence, complementing traditional queries by textual key words only. Efficient computational algorithms are required in order to "extract" structural information of the 3D images prior to storing them in the database. Also, easy-to-use interfaces should be implemented in order to obtain feedback from the expert. Our query-by-content prototype is used to construct a concrete query, making use of basic structural features, which are then evaluated over a set of three-dimensional images of biological macromolecules. This experimental implementation can be accessed via the Web at the BioImage server in Madrid, at http://www.bioimage.org/qbc/index.html.

  12. Optical design study and prototyping of a dual-field zoom lens imaging in the 1-5 micron infrared waveband

    NASA Astrophysics Data System (ADS)

    Reshidko, Dmitry; Reshidko, Pavel; Carmeli, Ran

    2015-09-01

    Optical systems can provide simultaneous imaging in several spectral bands and thus be much more useful. A new and current generation of focal plane arrays is allowing detection in more than one spectral region. The design of a refractive imaging lens for such detectors requires correcting chromatic aberrations over the wider range of wavelengths. However, the fewer available refracting materials, the material properties that change between the spectral bands, and the system transmission requirements make the design of such lenses particularly challenging. We present a dual-field zoom lens designed for a cooled detector sensing across short-wave infrared (SWIR) and midwave infrared (MWIR) spectral bands (continuous imaging for 1-5 μm). This zoom lens has a 75 mm focal length in the wide mode and a 250mm focal length in the narrow mode, and operates at f/4.7 in both discrete zoom positions. The lens is actively compensated to work in thermal environments from -20°C to +60°C. We discuss the optical design methodology, review the selection of materials and coatings for the optical elements, and analyze the transmission of the lens and optical performance. A prototype system has been manufactured and assembled. We validate our design with experimental data.

  13. Comparing satellite- to ground-based automated and manual cloud coverage observations - a case study

    NASA Astrophysics Data System (ADS)

    Werkmeister, A.; Lockhoff, M.; Schrempf, M.; Tohsing, K.; Liley, B.; Seckmeyer, G.

    2015-05-01

    In this case study we compare cloud fractional cover measured by radiometers on polar satellites (AVHRR) and on one geostationary satellite (SEVIRI) to ground-based manual (SYNOP) and automated observations by a cloud camera (Hemispherical Sky Imager, HSI). These observations took place in Hannover, Germany, and in Lauder, New Zealand, over time frames of 3 and 2 months, respectively. Daily mean comparisons between satellite derivations and the ground-based HSI found the deviation to be 6 ± 14% for AVHRR and 8 ± 16% for SEVIRI, which can be considered satisfactory. AVHRR's instantaneous differences are smaller (2 ± 22%) than instantaneous SEVIRI cloud fraction estimates (8 ± 29%) when compared to HSI due to resolution and scenery effect issues. All spaceborne observations show a very good skill in detecting completely overcast skies (cloud cover ≥ 6 oktas) with probabilities between 92 and 94% and false alarm rates between 21 and 29% for AVHRR and SEVIRI in Hannover, Germany. In the case of a clear sky (cloud cover lower than 3 oktas) we find good skill with detection probabilities between 72 and 76%. We find poor skill, however, whenever broken clouds occur (probability of detection is 32% for AVHRR and 12% for SEVIRI in Hannover, Germany). In order to better understand these discrepancies we analyze the influence of algorithm features on the satellite-based data. We find that the differences between SEVIRI and HSI cloud fractional cover (CFC) decrease (from a bias of 8 to almost 0%) with decreasing number of spatially averaged pixels and decreasing index which determines the cloud coverage in each "cloud-contaminated" pixel of the binary map. We conclude that window size and index need to be adjusted in order to improve instantaneous SEVIRI and AVHRR estimates. Due to its automated operation and its spatial, temporal and spectral resolution, we recommend as well that more automated ground-based instruments in the form of cloud cameras should be installed

  14. Status of the VERITAS ground based GeV/TeV Gamma-Ray Observatory

    NASA Astrophysics Data System (ADS)

    Kieda, D. B.; VERITAS Collaboration

    2004-08-01

    VERITAS is an array of 12-m diameter Imaging atmospheric Cerenkov telescopes for the study of GeV/TeV gamma radiation from astrophysical sources such as AGN, supernova remnants, and dark matter annihilation. The VERITAS telescope array will be located in Horseshoe Canyon on Kitt Peak, Arizona. VERITAS is scheduled to be completed by mid 2006. A prototype telescope has operated at the basecamp of the F.L. Whipple Observatory (Amado, Arizona) during the 2003-2004 season. This telescope was upgraded to full telescope status (with a full reflector area and fully instrumented camera)during the Summer/Fall 2004. We report on the status of the VERITAS observatory, including observations of the Crab Nebula and Mkn 421 by the prototype telescope during the past year. We provide estimates of the energy threshold and the sensitivity of the prototype in comparison to the existing Whipple 10 m telescope.

  15. Monte Carlo simulation of small OpenPET prototype with (11)C beam irradiation: effects of secondary particles on in-beam imaging.

    PubMed

    Hirano, Yoshiyuki; Yoshida, Eiji; Kinouchi, Shoko; Nishikido, Fumihiko; Inadma, Naoko; Murayama, Hideo; Yamaya, Taiga

    2014-04-07

    In-beam positron emission tomography (PET) can enable visualization of an irradiated field using positron emitters (β+ decay). In particle therapies, many kinds of secondary particles are produced by nuclear interactions, which affect PET imaging. Our purpose in this work was to evaluate effects of secondary particles on in-beam PET imaging using the Monte Carlo simulation code, Geant4, by reproducing an experiment with a small OpenPET prototype in which a PMMA phantom was irradiated by a (11)C beam. The number of incident particles to the detectors and their spectra, background coincidence for the PET scan, and reconstructed images were evaluated for three periods, spill-time (beam irradiation), pause-time (accelerating the particles) and beam-off time (duration after the final spill). For spill-time, we tested a background reduction technique in which coincidence events correlated with the accelerator radiofrequency were discarded (RF gated) that has been proposed in the literature. Also, background generation processes were identified. For spill-time, most background coincidences were caused by prompt gamma rays, and only 1.4% of the total coincidences generated β+ signals. Differently, for pause-time and beam-off time, more than 75% of the total coincidence events were signals. Using these coincidence events, we failed to reconstruct images during the spill-time, but we obtained successful reconstructions for the pause-time and beam-off time, which was consistent with the experimental results. From the simulation, we found that the absence of materials in the beam line and using the RF gated technique improved the signal-to-noise ratio for the spill-time. From an additional simulation with range shifter-less irradiation and the RF gated technique, we showed the feasibility of image reconstruction during the spill-time.

  16. Monte Carlo simulation of small OpenPET prototype with 11C beam irradiation: effects of secondary particles on in-beam imaging

    NASA Astrophysics Data System (ADS)

    Hirano, Yoshiyuki; Yoshida, Eiji; Kinouchi, Shoko; Nishikido, Fumihiko; Inadma, Naoko; Murayama, Hideo; Yamaya, Taiga

    2014-04-01

    In-beam positron emission tomography (PET) can enable visualization of an irradiated field using positron emitters (β+ decay). In particle therapies, many kinds of secondary particles are produced by nuclear interactions, which affect PET imaging. Our purpose in this work was to evaluate effects of secondary particles on in-beam PET imaging using the Monte Carlo simulation code, Geant4, by reproducing an experiment with a small OpenPET prototype in which a PMMA phantom was irradiated by a 11C beam. The number of incident particles to the detectors and their spectra, background coincidence for the PET scan, and reconstructed images were evaluated for three periods, spill-time (beam irradiation), pause-time (accelerating the particles) and beam-off time (duration after the final spill). For spill-time, we tested a background reduction technique in which coincidence events correlated with the accelerator radiofrequency were discarded (RF gated) that has been proposed in the literature. Also, background generation processes were identified. For spill-time, most background coincidences were caused by prompt gamma rays, and only 1.4% of the total coincidences generated β+ signals. Differently, for pause-time and beam-off time, more than 75% of the total coincidence events were signals. Using these coincidence events, we failed to reconstruct images during the spill-time, but we obtained successful reconstructions for the pause-time and beam-off time, which was consistent with the experimental results. From the simulation, we found that the absence of materials in the beam line and using the RF gated technique improved the signal-to-noise ratio for the spill-time. From an additional simulation with range shifter-less irradiation and the RF gated technique, we showed the feasibility of image reconstruction during the spill-time.

  17. Which future for electromagnetic Astronomy: Ground Based vs Space Borne Large Astrophysical Facilities

    NASA Astrophysics Data System (ADS)

    Ubertini, Pietro

    2015-08-01

    The combined use of large ground based facilities and large space observatories is playing a key role in the advance of astrophysics by providing access to the entire electromagnetic spectrum, allowing high sensitivity observations from the lower radio wavelength to the higher energy gamma rays.It is nowadays clear that a forward steps in the understanding of the Universe evolution and large scale structure formation is essential and only possible with the combined use of multiwavelength imaging and spectral high resolution instruments.The increasing size, complexity and cost of large ground and space observatories places a growing emphasis on international collaboration. If the present set of astronomical facilities is impressive and complete, with nicely complementary space and ground based telescopes, the scenario becomes worrisome and critical in the next two decades. In fact, only a few ‘Large’ main space missions are planned and there is a need to ensure proper ground facility coverage: the synergy Ground-Space is not escapable in the timeframe 2020-2030.The scope of this talk is to review the current astronomical instrumentation panorama also in view of the recent major national agencies and international bodies programmatic decisions.This Division B meeting give us a unique opportunity to review the current situation and discuss the future perspectives taking advantage of the large audience ensured by the IAU GA.

  18. Education and Public Outreach for MSFC's Ground-based Observations in Support of the HESSI Mission

    NASA Astrophysics Data System (ADS)

    Adams, M.; Hagyard, M. J.; Newton, E.

    1999-05-01

    A primary focus of NASA is the advancement of science and the communication of these advances to a number of audiences, both within the science research community and outside it. The upcoming High Energy Solar Spectroscopic Imager (HESSI) mission and the MSFC ground-based observing program, provide an excellent opportunity to communicate our knowledge of the Sun, its cycle of activity, the role of magnetic fields in that activity, and its effect on our planet. In addition to ground-based support of the HESSI mission, MSFC's Solar Observatory, located in North Alabama, will involve students and the local education community in its day-to-day operations, an experience which is more immediate, personal, and challenging than their everyday educational experience. Further, by taking advantage of the Internet, our program can reach beyond the immediate community. By joining with Fernbank Science Center in Atlanta, Georgia, we will leverage their almost 30 years' experience in science program delivery in diverse situations to a distance learning opportunity which can encompass the entire Southeast and beyond. This poster will outline our education and public outreach plans in support of the HESSI mission in which we will target middle and high school students and their teachers.

  19. Impact of focusing of Ground Based SAR data on the quality of interferometric SAR applications

    NASA Astrophysics Data System (ADS)

    Zonno, Mariantonietta; Mascolo, Luigi; Guccione, Pietro; Nico, Giovanni; Di Pasquale, Andrea

    2014-10-01

    A Ground-Based Synthetic Aperture Radar (GB-SAR) is nowadays employed in several applications. The processing of ground-based, space and airborne SAR data relies on the same physical principles. Nevertheless specific algorithms for the focusing of data acquired by GB-SAR system have been proposed in literature. In this work the impact of the main focusing methods on the interferometric phase dispersion and on the coherence has been studied by employing a real dataset obtained by carrying out an experiment. Several acquisitions of a scene with a corner reflector mounted on a micrometric screw have been made; before some acquisitions the micrometric screw has been displaced of few millimetres in the Line-of-Sight direction. The images have been first focused by using two different algorithms and correspondently, two different sets of interferograms have been generated. The mean and standard deviation of the phase values in correspondence of the corner reflector have been compared to those obtained by knowing the real displacement of the micrometric screw. The mean phase and its dispersion and the coherence values for each focusing algorithm have been quantified and both the precision and the accuracy of the interferometic phase measurements obtained by using the two different focusing methods have been assessed.

  20. Education and Public Outreach for MSFC's Ground-Based Observations in Support of the HESSI Mission

    NASA Technical Reports Server (NTRS)

    Adams, Mitzi L.; Hagyard, Mona J.; Newton, Elizabeth K.

    1999-01-01

    A primary focus of NASA is the advancement of science and the communication of these advances to a number of audiences, both within the science research community and outside it. The upcoming High Energy Solar Spectroscopic Imager (HESSI) mission and the MSFC ground-based observing program, provide an excellent opportunity to communicate our knowledge of the Sun, its cycle of activity, the role of magnetic fields in that activity, and its effect on our planet. In addition to ground-based support of the HESSI mission, MSFC's Solar Observatory, located in North Alabama, will involve students and the local education community in its day-to-day operations, an experience which is more immediate, personal, and challenging than their everyday educational experience. Further, by taking advantage of the Internet, our program can reach beyond the immediate community. By joining with Fernbank Science Center in Atlanta, Georgia, we will leverage their almost 30 years'experience in science program delivery in diverse situations to a distance learning opportunity which can encompass the entire Southeast and beyond. This poster will outline our education and public outreach plans in support of the HESSI mission in which we will target middle and high school students and their teachers.

  1. Development of PIAA Complex Mask Coronagraphs for large aperture ground-based telescopes

    NASA Astrophysics Data System (ADS)

    Newman, Kevin; Sirbu, Dan; Belikov, Ruslan; Guyon, Olivier

    2016-07-01

    The Phase Induced Amplitude Apodization Complex Mask Coronagraph (PIAACMC) is an architecture for directly observing extra-solar planets, and can achieve performance near the theoretical limits for any direct-detection instrument. The PIAACMC architecture includes aspheric PIAA optics, and a complex phase-shifting focal plane mask that provides a pi phase shift to a portion of the on-axis starlight. The phase-shifted starlight is forced to interfere destructively with the un-shifted starlight, causing the starlight to be eliminated, and allowing a region for high-contrast imaging near the star. The PIAACMC architecture can be designed for segmented and obscured apertures, so it is particularly well suited for ground-based observing with the next generation of large telescopes. There will be unique scientific opportunities for directly observing Earth-like planets around nearby low-mass stars. We will discuss design strategies for adapting PIAACMC for the next generation of large ground-based telescopes, and present progress on the development of the focal plane mask technology. We also present simulations of wave-front control with PIAACMC, and suggest directions to apply the coronagraph architecture to future telescopes.

  2. Education and Public Outreach for MSFC's Ground-Based Observations in Support of the HESSI Mission

    NASA Technical Reports Server (NTRS)

    Adams, Mitzi L.; Hagyard, Mona J.; Newton, Elizabeth K.

    1999-01-01

    A primary focus of NASA is the advancement of science and the communication of these advances to a number of audiences, both within the science research community and outside it. The upcoming High Energy Solar Spectroscopic Imager (HESSI) mission and the MSFC ground-based observing program, provide an excellent opportunity to communicate our knowledge of the Sun, its cycle of activity, the role of magnetic fields in that activity, and its effect on our planet. In addition to ground-based support of the HESSI mission, MSFC's Solar Observatory, located in North Alabama, will involve students and the local education community in its day-to-day operations, an experience which is more immediate, personal, and challenging than their everyday educational experience. Further, by taking advantage of the Internet, our program can reach beyond the immediate community. By joining with Fernbank Science Center in Atlanta, Georgia, we will leverage their almost 30 years'experience in science program delivery in diverse situations to a distance learning opportunity which can encompass the entire Southeast and beyond. This poster will outline our education and public outreach plans in support of the HESSI mission in which we will target middle and high school students and their teachers.

  3. Ground based detection of the plasmapause and the density of the plasmasphere

    NASA Astrophysics Data System (ADS)

    Heilig, Balázs; Darrouzet, Fabien; Friedel, Reinhard H.; Lichtenberger, János; Vellante, Massimo

    2014-05-01

    Although our knowledge on the plasmasphere dynamics has improved greatly thanks to some recent space missions (IMAGE, Cluster), continuous monitoring of the plasmapause position and plasma density remains unsolved. Ground based observation of geomagnetic field line resonances (FLRs) has the potential to achieve this goal. A meridional array of properly spaced magnetometers, such as EMMA (European quasi - Meridional Magnetometer Array, setup in frame of the PLASMON EU FP7 project), can provide dayside plasma density profiles. Compared to VLF whistlers, the other ground based source of plasmasphere density, FLRs have the advantage that they are often observed not only in the plasmasphere, but also outside it, in the plasmatrough, making them suitable for the detection of the plasmapause. The detection of FLRs is based on the amplitude and phase gradient observed between stations closely spaced in North-South direction. At normal conditions FLRs can be identified by a maximum in the cross phase spectra. Under special conditions, near the plasmapause the phase difference is reverted giving a minimum at the resonance frequency. This feature yields another possibility for the detection of the plasmapause. We present some events to demonstrate how the motion of the plasmapause can be monitored by means of EMMA. Results are compared to in-situ plasma density/plasmapause observations (WHISPER data onboard Cluster, EMFISIS data onboard Van Allen Probe) and some empirical models.

  4. Ten years of medical imaging standardization and prototypical implementation: the DICOM standard and the OFFIS DICOM toolkit (DCMTK)

    NASA Astrophysics Data System (ADS)

    Eichelberg, Marco; Riesmeier, Joerg; Wilkens, Thomas; Hewett, Andrew J.; Barth, Andreas; Jensch, Peter

    2004-04-01

    In 2003, the DICOM standard celebrated its 10th anniversary. Aside from the standard itself, also OFFIS" open source DICOM toolkit DCMTK, which has continuously followed the development of DICOM, turns 10 years old. On this occasion, this article looks back at the main standardization efforts in DICOM and illustrates related developments in DCMTK. Considering the development of the DICOM standard, it is possible to distinguish several phases of progress. Within the first phase at the beginning of the 1990s, basic network services for image transfer and retrieval were being introduced. The second phase, in the mid 1990s, was characterized by advances in the specification of a file format and of regulations for media interchange. In the later but partly parallel third phase, DICOM predominantly dealt with the problem of optimizing the workflow within imaging departments. As a result of the fact that it was now possible to exchange images between different systems, efforts concerning image display consistency followed in a fourth phase at the end of the 1990s. In the current fifth phase, security enhancements are being integrated into the standard. In another phase of progress, which took place over a relatively long time period concurrently to the other mentioned phases, DICOM Structured Reporting was developed.

  5. Ground-based passive FT-IR spectrometry

    NASA Astrophysics Data System (ADS)

    Knapp, Robert B.; Combs, Roger J.; Kroutil, Robert T.

    2002-02-01

    Absorbance and transmittance spectra were acquired with ground-based passive FT-IR spectrometry for industrial stack evaluations and open-air controlled vapor generation experiments. The industrial stack effluents of sulfur dioxide and nitrous oxide were detected from a coal-burning power plant and an acid plant, respectively, with both MWIR and LWIR passive sensors. The controlled open-air experiments relied on only a LWIR sensor. These experiments produced plumes of methanol and ethanol at three and four elevated plume temperatures, respectively. Various vapor concentration pathlength produces of both ethanol and methanol were generated and gravimetrically monitored in the range from 0 to 300 ppm-m. The associated absorbance values for these concentration pathlength products were found to obey Beer's Law for each elevate stack temperature of 125, 150, 175, and 200 degrees C.

  6. Modelling atmospheric turbulence effects on ground-based telescope systems

    SciTech Connect

    Bradford, L.W.; Flatte, S.M.; Max, C.E.

    1993-09-30

    Questions still exist concerning the appropriate model for turbulence- induced phase fluctuations seen in ground-based telescopes. Bester et al. used a particular observable (slope of the Allan variance) with an infrared interferometer in an attempt to distinguish models. The authors have calculated that observable for Kolmogorov and {open_quotes}random walk{close_quotes} models with a variety of outer scales and altitude-dependent turbulence and wind velocity. The authors have found that clear distinction between models requires good data on the vertical distribution of wind and turbulence. Furthermore, measurements at time separations of order 60 s are necessary to distinguish the {open_quotes}random walk{close_quotes} model from the Kolmogorov model.

  7. Responds of Bone Cells to Microgravity: Ground-Based Research

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Li, Jingbao; Xu, Huiyun; Yang, Pengfei; Xie, Li; Qian, Airong; Zhao, Yong; Shang, Peng

    2015-11-01

    Severe loss of bone occurs due to long-duration spaceflight. Mechanical loading stimulates bone formation, while bone degradation happens under mechanical unloading. Bone remodeling is a dynamic process in which bone formation and bone resorption are tightly coupled. Increased bone resorption and decreased bone formation caused by reduced mechanical loading, generally result in disrupted bone remodeling. Bone remodeling is orchestrated by multiple bone cells including osteoblast, osteocyte, osteoclast and mesenchymal stem cell. It is yet not clear that how these bone cells sense altered gravity, translate physical stimulus into biochemical signals, and then regulate themselves structurally and functionally. In this paper, studies elucidating the bioeffects of microgravity on bone cells (osteoblast, osteocyte, osteoclast, mesenchymal stem cell) using various platforms including spaceflight and ground-based simulated microgravity were summarized. Promising gravity-sensitive signaling pathways and protein molecules were proposed.

  8. Spatial-angular modeling of ground-based biaxial lidar

    NASA Astrophysics Data System (ADS)

    Agishev, Ravil R.

    1997-10-01

    Results of spatial-angular LIDAR modeling based on an efficiency criterion introduced are represented. Their analysis shows that a low spatial-angular efficiency of traditional VIS and NIR systems is a main cause of a low S/BR ratio at the photodetector input. It determines the considerable measurements errors and the following low accuracy of atmospheric optical parameters retrieval. As we have shown, the most effective protection against intensive sky background radiation for ground-based biaxial LIDAR's consist in forming of their angular field according to spatial-angular efficiency criterion G. Some effective approaches to high G-parameter value achievement to achieve the receiving system optimization are discussed.

  9. Unique cell culture systems for ground based research

    NASA Technical Reports Server (NTRS)

    Lewis, Marian L.

    1990-01-01

    The horizontally rotating fluid-filled, membrane oxygenated bioreactors developed at NASA Johnson for spacecraft applications provide a powerful tool for ground-based research. Three-dimensional aggregates formed by cells cultured on microcarrier beads are useful for study of cell-cell interactions and tissue development. By comparing electron micrographs of plant seedlings germinated during Shuttle flight 61-C and in an earth-based rotating bioreactor it is shown that some effects of microgravity are mimicked. Bioreactors used in the UAH Bioreactor Laboratory will make it possible to determine some of the effects of altered gravity at the cellular level. Bioreactors can be valuable for performing critical, preliminary-to-spaceflight experiments as well as medical investigations such as in vitro tumor cell growth and chemotherapeutic drug response; the enrichment of stem cells from bone marrow; and the effect of altered gravity on bone and muscle cell growth and function and immune response depression.

  10. Unique cell culture systems for ground based research

    NASA Technical Reports Server (NTRS)

    Lewis, Marian L.

    1990-01-01

    The horizontally rotating fluid-filled, membrane oxygenated bioreactors developed at NASA Johnson for spacecraft applications provide a powerful tool for ground-based research. Three-dimensional aggregates formed by cells cultured on microcarrier beads are useful for study of cell-cell interactions and tissue development. By comparing electron micrographs of plant seedlings germinated during Shuttle flight 61-C and in an earth-based rotating bioreactor it is shown that some effects of microgravity are mimicked. Bioreactors used in the UAH Bioreactor Laboratory will make it possible to determine some of the effects of altered gravity at the cellular level. Bioreactors can be valuable for performing critical, preliminary-to-spaceflight experiments as well as medical investigations such as in vitro tumor cell growth and chemotherapeutic drug response; the enrichment of stem cells from bone marrow; and the effect of altered gravity on bone and muscle cell growth and function and immune response depression.

  11. Ground-Based Experiments on Vibrational Thermal Convection

    NASA Technical Reports Server (NTRS)

    Schatz, Michael F.; Rogers, Jeffrey L.

    1999-01-01

    Ground-based experiments on g-jitter effects in fluid flow provide insight that complements both theoretical studies and space-based experiments on this problem. We report preliminary results for experiments on Rayleigh-Benard convection subjected to time-dependent accelerations on a shaker table. For sinusoidal modulation, two qualitatively different pattern forming mechanisms come into play: geometry induced wavenumber selection (as in the standard "no-shake" Rayleigh-Benard problem) and dispersion induced wavenumber selection due to parametric instability (as in the Faraday surface-wave problem). We discuss preliminary results on the competition and co-existence of patterns due to these different instability mechanisms. We also discuss the implications of this work on the general question of pattern formation in the presence of noise.

  12. Ground-based column abundance measurements of atmospheric hydroxyl

    NASA Astrophysics Data System (ADS)

    Burnett, Clyde R.

    1988-04-01

    The preliminary results of ground-based OH column abundance measurements from Truk, Federated States of Micronesia, are contained. These are the first OH column measurements from the tropics, and constitute a signficcant contribution to the OH data base. Comparisons of tropical OH behavior with the extensive mid-latitude observations serve as a critical test of the current understanding of the HO (sub x) photochemistry and its relationship to the other major chemical families. The quasi-biennial oscillation (QBO) in tropical stratospheric winds exerts a major influence on the Hadley cell vertical transport. Related QBOs in total O3 and in stratospheric H2O were identified, but QBO effects on other stratospheric species are still unknown. The solar tide in the tropics produces a diurnal surface pressure variation of 2 to 3 mb; its effect on OH photochemistry in the stratosphere may be significant.

  13. Ground-based column abundance measurements of atmospheric hydroxyl

    NASA Technical Reports Server (NTRS)

    Burnett, Clyde R.

    1988-01-01

    The preliminary results of ground-based OH column abundance measurements from Truk, Federated States of Micronesia, are contained. These are the first OH column measurements from the tropics, and constitute a signficcant contribution to the OH data base. Comparisons of tropical OH behavior with the extensive mid-latitude observations serve as a critical test of the current understanding of the HO (sub x) photochemistry and its relationship to the other major chemical families. The quasi-biennial oscillation (QBO) in tropical stratospheric winds exerts a major influence on the Hadley cell vertical transport. Related QBOs in total O3 and in stratospheric H2O were identified, but QBO effects on other stratospheric species are still unknown. The solar tide in the tropics produces a diurnal surface pressure variation of 2 to 3 mb; its effect on OH photochemistry in the stratosphere may be significant.

  14. Observational Selection Effects with Ground-based Gravitational Wave Detectors

    NASA Astrophysics Data System (ADS)

    Chen, Hsin-Yu; Essick, Reed; Vitale, Salvatore; Holz, Daniel; Katsavounidis, Erik

    2017-01-01

    Ground-based interferometers are not perfectly all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean and, as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources' right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO's observations and electromagnetic follow-up. These effects can inform electromagnetic follow-up activities and optimization, including the possibility of directing observations even before gravitational-wave events occur.

  15. A New Ground-Based, Hourly Global Lightning Climatology

    NASA Astrophysics Data System (ADS)

    Virts, K.; Wallace, J. M.; Hutchins, M. L.; Holzworth, R. H.

    2012-12-01

    The seasonally and diurnally-varying frequency of lightning flashes provides a measure of the frequency of occurrence of intense convection and, as such, is an important aspect of the Earth's climate. Using continuous observations from the ground-based World-Wide Lightning Location Network (WWLLN), it is possible to generate a global lightning climatology that captures seasonal variations and resolves the diurnal cycle. Hourly lightning animations illuminate the interplay between sea breezes, mountain-valley wind systems, and remotely forced gravity waves in touching off thunderstorms in a variety of geographical settings, such as the Maritime Continent, the central Andes, and equatorial Africa. Examination of intraseasonal variations in lightning over the Maritime Continent reveals the impact of shifts in the low-level wind field on the development and propagation of thunderstorms during the Madden-Julian Oscillation.

  16. Free electron lasers as ground based space weapons

    NASA Astrophysics Data System (ADS)

    Goldstein, Gary R.

    1988-12-01

    The free electron laser (FEL) is the most promising directed energy weapon in the SDI program. Its theoretical underpinnings, present achievements and future prospects are reviewed. The general requirements of a ground based laser system are derived and are seen to be quite expensive to implement as well as being far beyond current technical capabilities. Atmospheric propagation effects, particularly Stimulated Raman Scattering, will make the transmission of adequate powers dubious. A summary of existing and proposed FEL parameters shows that, at best, future facilities will be many orders of magnitude away from the required GigaWatt average output powers in the visible or near infrared region. Prospects for FEL midcourse or terminal phase weapons are equally problematic, given the simple countermeasures available to the offense. Use as an ASAT weapon is less technically demanding, but of limited applicability given the vulnerability of an extensive space based targeting system.

  17. Progress in the ULTRA 1-m ground-based telescope

    NASA Astrophysics Data System (ADS)

    Romeo, Robert C.; Martin, Robert N.; Twarog, Bruce; Anthony-Twarog, Barbara; Taghavi, Ray; Hale, Rick; Etzel, Paul; Fesen, Rob; Shawl, Steve

    2006-06-01

    We present the technical status of the Ultra Lightweight Telescope for Research in Astronomy (ULTRA) program. The program is a 3-year Major Research Instrumentation (MRI) program funded by NSF. The MRI is a collaborative effort involving Composite Mirror Applications, Inc. (CMA), University of Kansas, San Diego State University and Dartmouth College. Objectives are to demonstrate the feasibility of carbon fiber reinforced plastic (CFRP) composite mirror technology for ground-based optical telescopes. CMA is spearheading the development of surface replication techniques to produce the optics, fabricating the 1m glass mandrel, and constructing the optical tube assembly (OTA). Presented will be an overview and status of the 1-m mandrel fabrication, optics development, telescope design and CFRP telescope fabrication by CMA for the ULTRA Telescope.

  18. Aerial and Ground-Based Remote Sensing In Central America

    NASA Technical Reports Server (NTRS)

    Sheets, Payson; Sever, Thomas L.; Conyers, Larry

    2003-01-01

    Remote sensing of archaeological features is most successful when instrumentation and imagery are carefully selected bearing in mind the nature of the remains and the local context. Instruments need to be calibrated to local conditions, and extensive field verification studies are necessary. This is illustrated by remote sensing in two research programs in Central America: the Arena1 Research Program in Costa Rica and the Ceren Research Program in El Salvador. Satellite and aircraft remote sensing was successful in the former, while the Ceren site required the development of ground-based geophysical exploration techniques. In both cases, remote sensing contributed information that was not available by any other means, thus allowing new interpretations and a fuller understanding of ancient societies.

  19. Telerobotic manipulator developments for ground-based space research

    NASA Technical Reports Server (NTRS)

    Herndon, J. N.; Babcock, S. M.; Butler, P. L.; Costello, H. M.; Glassell, R. L.; Kress, Reid L.; Kuban, D. P.; Rowe, J. C.; Williams, D. M.; Meintel, A. J.

    1988-01-01

    New opportunities for the application of telerobotic systems to enhance human intelligence and dexterity in the hazardous environment of space are presented by the National Aeronautics and Space Administration (NASA) Space Station Program. Because of the need for significant increases in extravehicular activity and the potential increase in hazards associated with space programs, emphasis is being heightened on telerobotic systems research and development. The Automation Technology Branch at NASA Langley Research Center currently is sponsoring the Laboratory Telerobotic Manipulator (LTM) program at Oak Ridge National Laboratory to develop and demonstrate ground-based telerobotic manipulator system hardware for research and demonstrations aimed at future NASA applications. The LTM incorporates traction drives, modularity, redundant kinematics, and state-of-the-art hierarchical control techniques to form a basis for merging the diverse technological domains of robust, high-dexterity teleoperations and autonomous robotic operation into common hardware to further NASA's research.

  20. Martian Meteorological Measurements Using Ground-Based Telescopes

    NASA Astrophysics Data System (ADS)

    Simpson, A.; Bailey, J.; Walter, M.; Crisp, D.

    2005-12-01

    An important component of the continuing Mars research program is the accurate determination of atmospheric and meteorological parameters, and analysis of how these parameters vary spatially and temporally. Ground-based observations are particularly useful in this regard, as they allow simultaneous global coverage and use of high-resolution spectroscopy to complement orbital measurements. Aside from the perils of atmospheric turbulence (correctable to some degree using adaptive optics), infrared observations of planetary atmospheres face another challenge -- correcting for the presence of telluric spectral lines. Based on atmospheric simulations using the SMART radiative transfer modelling tool1, we present evidence that the current technique of mitigating the effect of Earth's atmosphere by observing a nearby star of known spectral type (the ``standard star" method) can generate significant errors. Indeed, our simulations of measurements of the Martian 2-micron carbon dioxide band at a resolving power of 1000 produced variation between ``standard reduced" spectra and original modelled spectra of up to 50%2. Furthermore, we outline our proposed computational technique of iterative reduction by progressing modelled parameters towards observed values (which negates the ``standard star" issue), to be validated on data obtained from IRTF/Gemini South observations in October/November 2005, and present results to date. 1Meadows, V.S., Crisp, D., 1996, Ground-based near-infrared observations of the Venus nightside: The thermal structure and water abundance near the surface, JGR 101:E2, 4595 2Bailey, J. A., Simpson, A. J., Crisp, D., 2005, Correcting Infrared Spectra for Atmospheric Absorption, in preparation

  1. Uncertainty analysis of atmospheric variations from ground-based observations

    NASA Astrophysics Data System (ADS)

    Chang, K. L.; Petropavlovskikh, I. V.

    2016-12-01

    In year 2016, total column ozone levels continue to be influenced by the remaining levels of the man-made ozone depleting substances in the atmosphere. Ozone recovery is a much more subtle process as compared to the ozone depletion of the 1980s. The quality of ozone observations is important for understanding and interpreting of the trends.The interannual ozone variability is driven by various natural and climate related forcing. The sampling limitations of the ground-based networks complicates analysis of the state of ozone recovery globally and locally. Therefore, the detection of the recovery rates needs to be addressed with understanding of the measurement uncertainties. Total column ozone variations estimated using Dobson ground-based stations have been challenged by data inhomogeneity in time and by the irregularity of the spatial distribution of stations, as well as by interruptions in observation records. Understanding and measuring the inherent uncertainty in long-terms ozone changes is crucial for the understanding of recovery of ozone layer and effects of climate change on ozone recovery. In this talk we estimate errors resulting from the spatial interpolation of ozone records and construct a long-term zonal means using stochastic partial differential equation (SPDE) framework, an extension of Chang, Gullias and Fioletov (2015). We further present the uncertainty analysis of long-term ozone changes. The generalized additive models (changes associated with well-known proxies) and stochastic volatility models (i.e. unexpected changes or interruptions of the record), including the integrated nested Laplace approximation (INLA) approach, will be used for analysis of ozone records. The connection between spatial nonstationarity (non-constant relation with space) and the statistical estimation of volatility uncertainty will be assessed. The robustness of the space-time prediction of total column ozone trends will be addressed.

  2. On Advanced Estimation Techniques for Exoplanet Detection and Characterization Using Ground-based Coronagraphs.

    PubMed

    Lawson, Peter R; Poyneer, Lisa; Barrett, Harrison; Frazin, Richard; Caucci, Luca; Devaney, Nicholas; Furenlid, Lars; Gładysz, Szymon; Guyon, Olivier; Krist, John; Maire, Jérôme; Marois, Christian; Mawet, Dimitri; Mouillet, David; Mugnier, Laurent; Pearson, Iain; Perrin, Marshall; Pueyo, Laurent; Savransky, Dmitry

    2012-07-01

    The direct imaging of planets around nearby stars is exceedingly difficult. Only about 14 exoplanets have been imaged to date that have masses less than 13 times that of Jupiter. The next generation of planet-finding coronagraphs, including VLT-SPHERE, the Gemini Planet Imager, Palomar P1640, and Subaru HiCIAO have predicted contrast performance of roughly a thousand times less than would be needed to detect Earth-like planets. In this paper we review the state of the art in exoplanet imaging, most notably the method of Locally Optimized Combination of Images (LOCI), and we investigate the potential of improving the detectability of faint exoplanets through the use of advanced statistical methods based on the concepts of the ideal observer and the Hotelling observer. We propose a formal comparison of techniques using a blind data challenge with an evaluation of performance using the Receiver Operating Characteristic (ROC) and Localization ROC (LROC) curves. We place particular emphasis on the understanding and modeling of realistic sources of measurement noise in ground-based AO-corrected coronagraphs. The work reported in this paper is the result of interactions between the co-authors during a week-long workshop on exoplanet imaging that was held in Squaw Valley, California, in March of 2012.

  3. On Advanced Estimation Techniques for Exoplanet Detection and Characterization Using Ground-based Coronagraphs

    PubMed Central

    Lawson, Peter R.; Poyneer, Lisa; Barrett, Harrison; Frazin, Richard; Caucci, Luca; Devaney, Nicholas; Furenlid, Lars; Gładysz, Szymon; Guyon, Olivier; Krist, John; Maire, Jérôme; Marois, Christian; Mawet, Dimitri; Mouillet, David; Mugnier, Laurent; Pearson, Iain; Perrin, Marshall; Pueyo, Laurent; Savransky, Dmitry

    2015-01-01

    The direct imaging of planets around nearby stars is exceedingly difficult. Only about 14 exoplanets have been imaged to date that have masses less than 13 times that of Jupiter. The next generation of planet-finding coronagraphs, including VLT-SPHERE, the Gemini Planet Imager, Palomar P1640, and Subaru HiCIAO have predicted contrast performance of roughly a thousand times less than would be needed to detect Earth-like planets. In this paper we review the state of the art in exoplanet imaging, most notably the method of Locally Optimized Combination of Images (LOCI), and we investigate the potential of improving the detectability of faint exoplanets through the use of advanced statistical methods based on the concepts of the ideal observer and the Hotelling observer. We propose a formal comparison of techniques using a blind data challenge with an evaluation of performance using the Receiver Operating Characteristic (ROC) and Localization ROC (LROC) curves. We place particular emphasis on the understanding and modeling of realistic sources of measurement noise in ground-based AO-corrected coronagraphs. The work reported in this paper is the result of interactions between the co-authors during a week-long workshop on exoplanet imaging that was held in Squaw Valley, California, in March of 2012. PMID:26347393

  4. On advanced estimation techniques for exoplanet detection and characterization using ground-based coronagraphs

    NASA Astrophysics Data System (ADS)

    Lawson, Peter R.; Poyneer, Lisa; Barrett, Harrison; Frazin, Richard; Caucci, Luca; Devaney, Nicholas; Furenlid, Lars; Gładysz, Szymon; Guyon, Olivier; Krist, John; Maire, Jérôme; Marois, Christian; Mawet, Dimitri; Mouillet, David; Mugnier, Laurent; Pearson, Iain; Perrin, Marshall; Pueyo, Laurent; Savransky, Dmitry

    2012-07-01

    The direct imaging of planets around nearby stars is exceedingly difficult. Only about 14 exoplanets have been imaged to date that have masses less than 13 times that of Jupiter. The next generation of planet-finding coronagraphs, including VLT-SPHERE, the Gemini Planet Imager, Palomar P1640, and Subaru HiCIAO have predicted contrast performance of roughly a thousand times less than would be needed to detect Earth-like planets. In this paper we review the state of the art in exoplanet imaging, most notably the method of Locally Optimized Combination of Images (LOCI), and we investigate the potential of improving the detectability of faint exoplanets through the use of advanced statistical methods based on the concepts of the ideal observer and the Hotelling observer. We propose a formal comparison of techniques using a blind data challenge with an evaluation of performance using the Receiver Operating Characteristic (ROC) and Localization ROC (LROC) curves. We place particular emphasis on the understanding and modeling of realistic sources of measurement noise in ground-based AO-corrected coronagraphs. The work reported in this paper is the result of interactions between the co-authors during a week-long workshop on exoplanet imaging that was held in Squaw Valley, California, in March of 2012.

  5. On Advanced Estimation Techniques for Exoplanet Detection and Characterization using Ground-Based Coronagraphs

    NASA Technical Reports Server (NTRS)

    Lawson, Peter R.; Frazin, Richard; Barrett, Harrison; Caucci, Luca; Devaney, Nicholas; Furenlid, Lars; Gladysz, Szymon; Guyon, Olivier; Krist, John; Maire, Jerome; Marois, Christian; Mawet, Dimitri; Mouillet, David; Mugnier, Laurent; Perrin, Marshall; Poyneer, Lisa; Pueyo, Laurent; Savransky, Dmitry; Soummer, Remi

    2012-01-01

    The direct imaging of planets around nearby stars is exceedingly difficult. Only about 14 exoplanets have been imaged to date that have masses less than 13 times that of Jupiter. The next generation of planet-finding coronagraphs, including VLT-SPHERE, the Gemini Planet Imager, Palomar P1640, and Subaru HiCIAO have predicted contrast performance of roughly a thousand times less than would be needed to detect Earth-like planets. In this paper we review the state of the art in exoplanet imaging, most notably the method of Locally Optimized Combination of Images (LOCI), and we investigate the potential of improving the detectability of faint exoplanets through the use of advanced statistical methods based on the concepts of the ideal observer and the Hotelling observer. We provide a formal comparison of techniques through a blind data challenge and evaluate performance using the Receiver Operating Characteristic (ROC) and Localization ROC (LROC) curves. We place particular emphasis on the understanding and modeling of realistic sources of measurement noise in ground-based AO-corrected coronagraphs. The work reported in this paper is the result of interactions between the co-authors during a week-long workshop on exoplanet imaging that was held in Squaw Valley, California, in March of 2012.

  6. On Advanced Estimation Techniques for Exoplanet Detection and Characterization using Ground-based Coronagraphs

    NASA Technical Reports Server (NTRS)

    Lawson, Peter; Frazin, Richard

    2012-01-01

    The direct imaging of planets around nearby stars is exceedingly difficult. Only about 14 exoplanets have been imaged to date that have masses less than 13 times that of Jupiter. The next generation of planet-finding coronagraphs, including VLT-SPHERE, the Gemini Planet Imager, Palomar P1640, and Subaru HiCIAO have predicted contrast performance of roughly a thousand times less than would be needed to detect Earth-like planets. In this paper we review the state of the art in exoplanet imaging, most notably the method of Locally Optimized Combination of Images (LOCI), and we investigate the potential of improving the detectability of faint exoplanets through the use of advanced statistical methods based on the concepts of the ideal observer and the Hotelling observer. We propose a formal comparison of techniques using a blind data challenge with an evaluation of performance using the Receiver Operating Characteristic (ROC) and Localization ROC (LROC) curves. We place particular emphasis on the understanding and modeling of realistic sources of measurement noise in ground-based AO-corrected coronagraphs. The work reported in this paper is the result of interactions between the co-authors during a week-long workshop on exoplanet imaging that was held in Squaw Valley, California, in March of 2012

  7. On the role of ground-based observations in substorm research: Can one recognize the beast from its foot prints?

    NASA Astrophysics Data System (ADS)

    Kauristie, K.

    2003-04-01

    The first coordinated efforts of ground-based auroral observations were carried out already during the International Geophysical Year (IGY) 1957-1958, during which all-sky camera pictures and magnetometer data were collected from several stations in the northern polar regions. This huge amount of data were later organized by Syun-Ichi Akasofu to describe the original auroral substorm concept, main parts of which belong also to the wider magnetospheric substorm schema which started to build up when satellite observations became available. Also the IGY concept is still living strong as versatile networks of ground-based instruments support the ambitious international satellite missions (like Cluster or ILWS) investigating the different solar-terrestrial coupling processes. Many magnetospheric substorm processes have their own specific ionospheric signatures. Consequently, ground-based observations are often used to provide the background context that helps the interpretation of the localized magnetospheric satellite observations. The possibility to analyse phenomena of very different scale sizes is a further advantage. With the modern high-resolution imagers auroral structures of less than kilometer-scale can be analysed. On the other hand, with the combination of the data of the global SuperDARN network and several magnetometer networks the entire polar cap convection and current pattern can be monitored. The development of various data analysis tools and assimilation methods has pushed the interpretation of ground-based data towards more quantitative analysis and resulted in several important findings. In the presentation we will discuss the benefits and pitfalls of ground-based observations, review the most important contributions to substorm research, and envisage some of the future challenges.

  8. Ground-Based Deep-Penetrating Radar Studies Along The US-ITASE Traverse

    NASA Astrophysics Data System (ADS)

    Jacobel, R. W.; Welch, B. C.; Bills, M. T.; Engle, T. J.

    2003-12-01

    In recent years airborne geophysical surveys have provided high-quality data over selected portions of the West Antarctic Ice Sheet (WAIS). Coupled with new information at visible and radar wavelengths from satellite sensors, these surveys have greatly enhanced our understanding of the dynamics of the WAIS. Until recently, ground-based radar studies have generally been limited to more localized areas and small-scale ice dynamics problems where they provide greater spatial resolution than airborne surveys, often with higher definition (S/N) of imaged features. During the past four years, the US-ITASE platform has provided an opportunity for ground-based deep radar profiling over several thousand kilometers of the WAIS and portions of the East Antarctic Ice Sheet, including more detailed studies of selected sites where ice cores have been drilled. These traverses have enabled us to produced high definition images of bedrock and internal stratigraphy on a continental scale, combining attributes of both airborne and ground-based surveys. We have developed a ruggedized impulse-based radar system to withstand the physical demands of a heavy vehicle traverse at speeds up to 15 Km/hr and also obtain data with high spatial resolution along-track and high definition of internal reflectors. Operating at a center frequency of 3 MHz this system utilizes a 14 bit A/D board at digitizing rates of 100 MHz and records stacked waveforms depicting bedrock and ice internal reflections approximately every 15 meters of surface travel. Surface coordinates are obtained from precision GPS measurements which together with the high data density enable us to migrate profile sections to correctly image steeply-dipping reflectors. We present here a sample of results from over 2000 km of profiles completed during the 2001-2003 field seasons, including routes from Byrd Station toward Siple Station and Byrd to South Pole. In addition to the bedrock record that identifies a number of new regions of

  9. SmartCard Prototype

    DTIC Science & Technology

    2009-09-01

    prototype. ............................................................................................. 7 Figure 6 Smart Card Prototype main window...a data explorer. Intervention costs Database with a single instance (i.e. one data set). User help framework Figure 6 Smart Card Prototype

  10. Extending a prototype knowledge and object based image analysis model to coarser spatial resolution imagery: an example from the Missouri River

    USGS Publications Warehouse

    Strong, Laurence L.

    2012-01-01

    A prototype knowledge- and object-based image analysis model was developed to inventory and map least tern and piping plover habitat on the Missouri River, USA. The model has been used to inventory the state of sandbars annually for 4 segments of the Missouri River since 2006 using QuickBird imagery. Interpretation of the state of sandbars is difficult when images for the segment are acquired at different river stages and different states of vegetation phenology and canopy cover. Concurrent QuickBird and RapidEye images were classified using the model and the spatial correspondence of classes in the land cover and sandbar maps were analysed for the spatial extent of the images and at nest locations for both bird species. Omission and commission errors were low for unvegetated land cover classes used for nesting by both bird species and for land cover types with continuous vegetation cover and water. Errors were larger for land cover classes characterized by a mixture of sand and vegetation. Sandbar classification decisions are made using information on land cover class proportions and disagreement between sandbar classes was resolved using fuzzy membership possibilities. Regression analysis of area for a paired sample of 47 sandbars indicated an average positive bias, 1.15 ha, for RapidEye that did not vary with sandbar size. RapidEye has potential to reduce temporal uncertainty about least tern and piping plover habitat but would not be suitable for mapping sandbar erosion, and characterization of sandbar shapes or vegetation patches at fine spatial resolution.

  11. Extending a prototype knowledge- and object-based image analysis model to coarser spatial resolution imagery: an example from the Missouri River

    USGS Publications Warehouse

    Strong, Laurence L.

    2012-01-01

    A prototype knowledge- and object-based image analysis model was developed to inventory and map least tern and piping plover habitat on the Missouri River, USA. The model has been used to inventory the state of sandbars annually for 4 se