Science.gov

Sample records for five-hour radiometric serum

  1. Development of a five-hour radiometric serum antibacterial assay for gram-positive cocci

    SciTech Connect

    Beckwith, D.G.; Guidon, P.T. Jr.

    1981-03-01

    A preliminary report on a 5-hr radiometric serum antibacterial assay (ABA) for Gram-positive cocci is presented. The method agreed within +- one twofold dilution with static ABA endpoints in 24/26 (92%) of the assays and with cidal ABA end-points in 23/26 (88%) of the assays performed.

  2. TES radiometric assessment

    NASA Technical Reports Server (NTRS)

    Worden, H.; Sarkissian, E.; Bowman, K.; Fisher, B.; Rider, D.; Aumann, H. H.; Apolinski, M.; Debaca, R. C.; Gluck, S.; Madatyan, M.; McDuffie, J.; Tremblay, D.; Shephard, M.; Cady-Pereira, K.; Tobin, D.; Revercomb, H.

    2005-01-01

    TES is an infrared Fourier transform spectrometer on board the EOS-Aura spacecraft launched July 15, 2004. Improvements to the radiometric calibration and consequent assessment of radiometric accuracy have been on-going since launch.

  3. Radiometric assays for glycerol, glucose, and glycogen.

    PubMed

    Bradley, D C; Kaslow, H R

    1989-07-01

    We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus (1971, J. Biol. Chem. 246, 3885-3894) for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with [32P]ATP and glycerokinase, residual [32P]ATP is hydrolyzed by heating in acid, and free [32P]phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays. PMID:2817333

  4. Radiometric assays for glycerol, glucose, and glycogen

    SciTech Connect

    Bradley, D.C.; Kaslow, H.R. )

    1989-07-01

    We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with (32P)ATP and glycerokinase, residual (32P)ATP is hydrolyzed by heating in acid, and free (32P)phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays.

  5. NASA IKONOS Radiometric Characterization

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Frisbee, Troy; Zanoni, Vicki; Blonski, Slawek; Daehler, Erik; Grant, Brennan; Holekamp, Kara; Ryan, Robert; Sellers, Richard; Smith, Charles

    2002-01-01

    The objective of this program: Perform radiometric vicarious calibrations of IKQNOS imagery and compare with Space Imaging calibration coefficients The approach taken: utilize multiple well-characterized sites which are widely used by the NASA science community for radiometric characterization of airborne and spaceborne sensors; and to Perform independent characterizations with independent teams. Each team has slightly different measurement techniques and data processing methods.

  6. Radiometric correction procedure study

    NASA Technical Reports Server (NTRS)

    Colby, C.; Sands, R.; Murphrey, S.

    1978-01-01

    A comparison of MSS radiometric processing techniques identified as a preferred radiometric processing technique a procedure which equalizes the mean and standard deviation of detector-specific histograms of uncalibrated scene data. Evaluation of MSS calibration data demonstrated that the relationship between detector responses is essentially linear over the range of intensities typically observed in MSS data, and that the calibration wedge data possess a high degree of temporal stability. An analysis of the preferred radiometric processing technique showed that it could be incorporated into the MDP-MSS system without a major redesign of the system, and with minimal impact on system throughput.

  7. Microwave radiometric systems.

    NASA Technical Reports Server (NTRS)

    Barath, F. T.

    1972-01-01

    Microwave radiometers measure thermal electromagnetic radiation at frequencies ranging over the entire radio spectrum, from audio to infrared. The temperatures of black-body radiators can be measured with sensitivities better than 0.01 K, and with absolute accuracies better than 0.5 K. Radiometric systems have been built with as many as 400 independent spectral channels. Frequency resolutions range from hertz to gigahertz; and integration times range from microseconds to hours. Radiometric systems have operated reliably on the ground, and in balloons, aircraft, and spacecraft, including the 1962 Mariner 2 planetary probe to Venus.

  8. Photovoltaics radiometric issues and needs

    SciTech Connect

    Myers, D.R.

    1995-11-01

    This paper presents a summary of issues discussed at the photovoltaic radiometric measurements workshop. Topics included radiometric measurements guides, the need for well-defined goals, documentation, calibration checks, accreditation of testing laboratories and methods, the need for less expensive radiometric instrumentation, data correlations, and quality assurance.

  9. Small satellite radiometric measurements

    SciTech Connect

    Weber, P.G.

    1991-01-01

    A critical need for the Mission to Planet Earth is to provide continuous, well-calibrated radiometric data for the radiation budget. This paper describes a new, compact, flexible radiometer which will provide both spectrally integrated data and data in selected spectral bands. The radiometer design is suitable for use on small satellites, aircraft, or remotely piloted vehicles (RPVs). 12 refs., 2 figs.

  10. Radiometric Dating Does Work!

    ERIC Educational Resources Information Center

    Dalrymple, G. Brent

    2000-01-01

    Discusses the accuracy of dating methods and creationist arguments that radiometric dating does not work. Explains the Manson meteorite impact and the Pierre shale, the ages of meteorites, the K-T tektites, and dating the Mount Vesuvius eruption. (Author/YDS)

  11. Simplified Vicarious Radiometric Calibration

    NASA Technical Reports Server (NTRS)

    Stanley, Thomas; Ryan, Robert; Holekamp, Kara; Pagnutti, Mary

    2010-01-01

    A measurement-based radiance estimation approach for vicarious radiometric calibration of spaceborne multispectral remote sensing systems has been developed. This simplified process eliminates the use of radiative transfer codes and reduces the number of atmospheric assumptions required to perform sensor calibrations. Like prior approaches, the simplified method involves the collection of ground truth data coincident with the overpass of the remote sensing system being calibrated, but this approach differs from the prior techniques in both the nature of the data collected and the manner in which the data are processed. In traditional vicarious radiometric calibration, ground truth data are gathered using ground-viewing spectroradiometers and one or more sun photometer( s), among other instruments, located at a ground target area. The measured data from the ground-based instruments are used in radiative transfer models to estimate the top-of-atmosphere (TOA) target radiances at the time of satellite overpass. These TOA radiances are compared with the satellite sensor readings to radiometrically calibrate the sensor. Traditional vicarious radiometric calibration methods require that an atmospheric model be defined such that the ground-based observations of solar transmission and diffuse-to-global ratios are in close agreement with the radiative transfer code estimation of these parameters. This process is labor-intensive and complex, and can be prone to errors. The errors can be compounded because of approximations in the model and inaccurate assumptions about the radiative coupling between the atmosphere and the terrain. The errors can increase the uncertainty of the TOA radiance estimates used to perform the radiometric calibration. In comparison, the simplified approach does not use atmospheric radiative transfer models and involves fewer assumptions concerning the radiative transfer properties of the atmosphere. This new technique uses two neighboring uniform

  12. Radiometric sounding system

    SciTech Connect

    Whiteman, C.D.; Anderson, G.A.; Alzheimer, J.M.; Shaw, W.J.

    1995-04-01

    Vertical profiles of solar and terrestrial radiative fluxes are key research needs for global climate change research. These fluxes are expected to change as radiatively active trace gases are emitted to the earth`s atmosphere as a consequence of energy production and industrial and other human activities. Models suggest that changes in the concentration of such gases will lead to radiative flux divergences that will produce global warming of the earth`s atmosphere. Direct measurements of the vertical variation of solar and terrestrial radiative fluxes that lead to these flux divergences have been largely unavailable because of the expense of making such measurements from airplanes. These measurements are needed to improve existing atmospheric radiative transfer models, especially under the cloudy conditions where the models have not been adequately tested. A tethered-balloon-borne Radiometric Sounding System has been developed at Pacific Northwest Laboratory to provide an inexpensive means of making routine vertical soundings of radiative fluxes in the earth`s atmospheric boundary layer to altitudes up to 1500 m above ground level. Such vertical soundings would supplement measurements being made from aircraft and towers. The key technical challenge in the design of the Radiometric Sounding System is to develop a means of keeping the radiometers horizontal while the balloon ascends and descends in a turbulent atmospheric environment. This problem has been addressed by stabilizing a triangular radiometer-carrying platform that is carried on the tetherline of a balloon sounding system. The platform, carried 30 m or more below the balloon to reduce the balloon`s effect on the radiometric measurements, is leveled by two automatic control loops that activate motors, gears and pulleys when the platform is off-level. The sensitivity of the automatic control loops to oscillatory motions of various frequencies and amplitudes can be adjusted using filters.

  13. [Laser-based radiometric calibration].

    PubMed

    Li, Zhi-gang; Zheng, Yu-quan

    2014-12-01

    Increasingly higher demands are put forward to spectral radiometric calibration accuracy and the development of new tunable laser based spectral radiometric calibration technology is promoted, along with the development of studies of terrestrial remote sensing, aeronautical and astronautical remote sensing, plasma physics, quantitative spectroscopy, etc. Internationally a number of national metrology scientific research institutes have built tunable laser based spectral radiometric calibration facilities in succession, which are traceable to cryogenic radiometers and have low uncertainties for spectral responsivity calibration and characterization of detectors and remote sensing instruments in the UK, the USA, Germany, etc. Among them, the facility for spectral irradiance and radiance responsivity calibrations using uniform sources (SIRCCUS) at the National Institute of Standards and Technology (NIST) in the USA and the Tunable Lasers in Photometry (TULIP) facility at the Physikalisch-Technische Bundesanstalt (PTB) in Germany have more representatives. Compared with lamp-monochromator systems, laser based spectral radiometric calibrations have many advantages, such as narrow spectral bandwidth, high wavelength accuracy, low calibration uncertainty and so on for radiometric calibration applications. In this paper, the development of laser-based spectral radiometric calibration and structures and performances of laser-based radiometric calibration facilities represented by the National Physical Laboratory (NPL) in the UK, NIST and PTB are presented, technical advantages of laser-based spectral radiometric calibration are analyzed, and applications of this technology are further discussed. Laser-based spectral radiometric calibration facilities can be widely used in important system-level radiometric calibration measurements with high accuracy, including radiance temperature, radiance and irradiance calibrations for space remote sensing instruments, and promote the

  14. Uncooled radiometric camera performance

    NASA Astrophysics Data System (ADS)

    Meyer, Bill; Hoelter, T.

    1998-07-01

    Thermal imaging equipment utilizing microbolometer detectors operating at room temperature has found widespread acceptance in both military and commercial applications. Uncooled camera products are becoming effective solutions to applications currently using traditional, photonic infrared sensors. The reduced power consumption and decreased mechanical complexity offered by uncooled cameras have realized highly reliable, low-cost, hand-held instruments. Initially these instruments displayed only relative temperature differences which limited their usefulness in applications such as Thermography. Radiometrically calibrated microbolometer instruments are now available. The ExplorIR Thermography camera leverages the technology developed for Raytheon Systems Company's first production microbolometer imaging camera, the Sentinel. The ExplorIR camera has a demonstrated temperature measurement accuracy of 4 degrees Celsius or 4% of the measured value (whichever is greater) over scene temperatures ranges of minus 20 degrees Celsius to 300 degrees Celsius (minus 20 degrees Celsius to 900 degrees Celsius for extended range models) and camera environmental temperatures of minus 10 degrees Celsius to 40 degrees Celsius. Direct temperature measurement with high resolution video imaging creates some unique challenges when using uncooled detectors. A temperature controlled, field-of-view limiting aperture (cold shield) is not typically included in the small volume dewars used for uncooled detector packages. The lack of a field-of-view shield allows a significant amount of extraneous radiation from the dewar walls and lens body to affect the sensor operation. In addition, the transmission of the Germanium lens elements is a function of ambient temperature. The ExplorIR camera design compensates for these environmental effects while maintaining the accuracy and dynamic range required by today's predictive maintenance and condition monitoring markets.

  15. Statistical synthesis of multiantenna ultrawideband radiometric complexes

    NASA Astrophysics Data System (ADS)

    Volosyuk, V. K.; Kravchenko, V. F.; Pavlikov, V. V.; Pustovoit, V. I.

    2016-04-01

    An optimum signal processing algorithm of radiometric imaging has been synthesized for the first time using multiantenna ultrawideband (UWB) radiometric complexes (RMCs). Radiometric images (RMI) are interpreted physically as intensity depending on the angular coordinates or the spectral radio brightness averaged in the operation frequency band. In accordance with the synthesized algorithm, a structural scheme of ultrawideband radiometric complexes has been developed. An analytical expression for the ambiguity function of radiometric complexes has been obtained. The ambiguity function is modeled in the case of processing narrowband and ultrawideband radiometric signals. As follows from the analysis of the results, new elements of the theory of optimum processing of UWB radiometric signals with the involvement of multielement antenna systems are an important tool in creating highly accurate, biologically and ecologically safe complexes for studying various media and objects.

  16. Radiometric method for the rapid detection of Leptospira organisms

    SciTech Connect

    Manca, N.; Verardi, R.; Colombrita, D.; Ravizzola, G.; Savoldi, E.; Turano, A.

    1986-02-01

    A rapid and sensitive radiometric method for detection of Leptospira interrogans serovar pomona and Leptospira interrogans serovar copenhageni is described. Stuart's medium and Middlebrook TB (12A) medium supplemented with bovine serum albumin, catalase, and casein hydrolysate and labeled with /sup 14/C-fatty acids were used. The radioactivity was measured in a BACTEC 460. With this system, Leptospira organisms were detected in human blood in 2 to 5 days, a notably shorter time period than that required for the majority of detection techniques.

  17. Small satellite radiometric measurement system

    SciTech Connect

    Weber, P.G.

    1992-01-01

    A critical need for the US Global Change Research Program is to provide continuous, well-calibrated radiometric data for the earth`s radiation budget. This paper describes a new, compact, relatively light-weight, adaptable radiometer which will provide both spectrally integrated measurements and data in selected spectral bands. The radiometer design is suitable for use on small satellites, aircraft, or remotely piloted aircraft (RPAs). An example of the implementation of this radiometer on a small satellite is given. Significant benefits derive from simultaneous measurements of specific narrow (in wavelength) spectral features; such data may be obtained by combining LARI with a compact spectrometer on the same platform. Well-chosen satellite orbits allow one to use data from other satellites (e.g. DMSP) to enhance the data product, or to provide superior coverage of specific locations. 23 refs.

  18. Microwave radiometric observations of snowpacks

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.; Stiles, W. H.

    1980-01-01

    Models for the microwave emission from snowpacks were generated on the basis of radiometric observations made at 10.7 GHz, 37 HGz, and 94 GHz at a test site near Steamboat Springs, Colorado. In addition to conducting measurements on an approximately daily basis over a six week observation period, measurements were made over several diurnal cycles during which the change in snow wetness was tracked by the microwave radiometers. Also, the variation in emissivity with snow water equivalent was examined, as was the sensitivity to changes in snow surface geometry. The microwave emissivity was observed to (1) decrease exponentially with snow water equivalent and (2) increase with snow wetness. Thus, the emission behavior is the reverse of the backscattering behavior observed by the radar. By fitting the models to the measured data, the variation of the optical depth with snow wetness was estimated.

  19. Survey of emissivity measurement by radiometric methods.

    PubMed

    Honner, M; Honnerová, P

    2015-02-01

    A survey of the state of the art in the field of spectral directional emissivity measurements by using radiometric methods is presented. Individual quantity types such as spectral, band, or total emissivity are defined. Principles of emissivity measurement by various methods (direct and indirect, and calorimetric and radiometric) are discussed. The paper is focused on direct radiometric methods. An overview of experimental setups is provided, including the design of individual parts such as the applied reference sources of radiation, systems of sample clamping and heating, detection systems, methods for the determination of surface temperature, and procedures for emissivity evaluation. PMID:25967774

  20. Radiometric surveys in underground environment

    NASA Astrophysics Data System (ADS)

    Bochiolo, Massimo; Chiozzi, Paolo; Verdoya, Massimo; Pasquale, Vincenzo

    2010-05-01

    Due to their ability to travel through the air for several metres, gamma-rays emitted from natural radioactive elements can be successfully used in surveys carried out both with airborne and ground equipments. Besides the concentration of the radio-elements contained in rocks and soils and the intrinsic characteristics of the gamma-ray detector, the detected count rate depends on the solid angle around the spectrometer. On a flat outcrop, ground spectrometry detects the radiation ideally produced by a cylindrical mass of rock of about two metres in diameter and thickness of about half a meter. Under these geometrical conditions, the natural radioactivity can be easily evaluated. With operating conditions different from the standard ones, such as at the edge of an escarpment, the count rate halves because of the missing material, whereas in the vicinity of a rock wall the count rate will increase. In underground environment, the recorded count rate may even double and the in situ assessment of the concentration of radio-elements may be rather difficult, even if the ratios between the different radio-elements may not be affected. We tested the applicability of gamma-ray spectrometry for rapid assessment of the potential hazard levels related to radon and radiation dose rate in underground environment. A mine shaft, located in a zone of uranium enrichment in Liguria (Italy), has been investigated. A preliminary ground radiometric survey was carried out to define the extent of the ore deposit. Then, the radiometric investigation was focussed on the mine shaft. Due to rock mass above the shaft vault, the background gamma radiation can be considered of negligible influence on measurements. In underground surveys, besides deviations from a flat geometry, factors controlling radon exhalation, emanation and stagnation, such as fractures, water leakage and the presence of ventilation, should be carefully examined. We attempted to evaluate these control factors and collected

  1. Azimuthal radiometric temperature measurements of wheat canopies

    NASA Technical Reports Server (NTRS)

    Kimes, D. S.

    1981-01-01

    The effects of azimuthal view angle on the radiometric temperature of wheat canopies at various stages of development are investigated. Measurements of plant height, total leaf area index, green leaf area index and Feeks growth stage together with infrared radiometric temperature measurements at 12 azimuth intervals with respect to solar azimuth and at different solar zenith angles were obtained for four wheat canopies at various heights. Results reveal a difference on the order of 2 C between the temperatures measured at azimuths of 0 and 180 deg under calm wind conditions, which is attributed to the time-dependent transfer of heat between canopy component surfaces. The azimuthal dependence must thus be taken into account in the determination of radiometric temperatures.

  2. AIRS radiometric calibration validation for climate research

    NASA Technical Reports Server (NTRS)

    Aumann, Hartmut H.; Pagano, Thomas S.; Elliott, Denis; Gaiser, Steve; Gregorich, Dave; Broberg, Steve

    2005-01-01

    Climate research using data from satellite based radiometers makes extreme demands on the traceability and stability of the radiometric calibration. The selection of a cooled grating array spectrometer for the Atmospheric Infrared Sounder, AIRS, is key, but does not ensured that AIRS data will be of climate quality. Additional design features, plus additional pre-launch testing, and extensive on-orbit calibration subsystem monitoring beyond what would suffice for application of the data to weather forecasting were required to ensure the radiometric data quality required for climate research. Validation that climate data quality are being generated makes use of the sea surface skin temperatures (SST and (obs-calc).

  3. Based on Narcissus of radiometric calibration technology

    NASA Astrophysics Data System (ADS)

    Jin, Libing; Tang, Shaofan; Liu, Jianfeng; Peng, Honggang

    2015-08-01

    Thermal radiation is an inherent property of all objects. Generally, it is believed that the body, which temperature is above absolute zero, can keep generating infrared radiation. Infrared remote sensing, using of satellite-borne or airborne sensors, collects infrared information to identify the surface feature and inversion of surface parameters, temperature, etc. In order to get more accurately feature information, quantitative measurement is required. Infrared radiometric calibration is one of the key technologies of quantitative infrared remote sensing. Most high-resolution thermal imaging systems are cooling. For the infrared optical system which is having a cooled detector, there are some special phenomenons. Since the temperature of the detector's photosensitive surface is generally low, which is very different from system temperature, it is a very strong cold radiation source. Narcissus refers to the case that the cooled detector can "see" its own reflecting image, which may affect the image quality of infrared system seriously. But for radiometric calibration of satellite-borne infrared camera, it can sometimes take advantage of the narcissus instead of cold cryogenic radiometric calibration. In this paper, the use of narcissus to carry out radiometric calibration is summarized, and simulation results show the feasibility.

  4. Kernel MAD Algorithm for Relative Radiometric Normalization

    NASA Astrophysics Data System (ADS)

    Bai, Yang; Tang, Ping; Hu, Changmiao

    2016-06-01

    The multivariate alteration detection (MAD) algorithm is commonly used in relative radiometric normalization. This algorithm is based on linear canonical correlation analysis (CCA) which can analyze only linear relationships among bands. Therefore, we first introduce a new version of MAD in this study based on the established method known as kernel canonical correlation analysis (KCCA). The proposed method effectively extracts the non-linear and complex relationships among variables. We then conduct relative radiometric normalization experiments on both the linear CCA and KCCA version of the MAD algorithm with the use of Landsat-8 data of Beijing, China, and Gaofen-1(GF-1) data derived from South China. Finally, we analyze the difference between the two methods. Results show that the KCCA-based MAD can be satisfactorily applied to relative radiometric normalization, this algorithm can well describe the nonlinear relationship between multi-temporal images. This work is the first attempt to apply a KCCA-based MAD algorithm to relative radiometric normalization.

  5. Radiometric considerations for ocean color remote sensors

    NASA Technical Reports Server (NTRS)

    Gordon, Howard R.

    1990-01-01

    A methodology for determination of the effects of radiometric noise on the performance of ocean color sensors is developed and applied to the Coastal Zone Color Scanner on Nimbus 7 and the Moderate Resolution Imaging Spectrometer planned for the Earth Observing System.

  6. Radiometric Characterization of IKONOS Multispectral Imagery

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Ryan, Robert E.; Kelly, Michelle; Holekamp, Kara; Zanoni, Vicki; Thome, Kurtis; Schiller, Stephen

    2002-01-01

    A radiometric characterization of Space Imaging's IKONOS 4-m multispectral imagery has been performed by a NASA funded team from the John C. Stennis Space Center (SSC), the University of Arizona Remote Sensing Group (UARSG), and South Dakota State University (SDSU). Both intrinsic radiometry and the effects of Space Imaging processing on radiometry were investigated. Relative radiometry was examined with uniform Antarctic and Saharan sites. Absolute radiometric calibration was performed using reflectance-based vicarious calibration methods on several uniform sites imaged by IKONOS, coincident with ground-based surface and atmospheric measurements. Ground-based data and the IKONOS spectral response function served as input to radiative transfer codes to generate a Top-of-Atmosphere radiance estimate. Calibration coefficients derived from each vicarious calibration were combined to generate an IKONOS radiometric gain coefficient for each multispectral band assuming a linear response over the full dynamic range of the instrument. These calibration coefficients were made available to Space Imaging, which subsequently adopted them by updating its initial set of calibration coefficients. IKONOS imagery procured through the NASA Scientific Data Purchase program is processed with or without a Modulation Transfer Function Compensation kernel. The radiometric effects of this kernel on various scene types was also investigated. All imagery characterized was procured through the NASA Scientific Data Purchase program.

  7. Radiometric surface temperature components for row crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature is a boundary condition often used in assessing soil moisture status and energy exchange from the soil-vegetation-atmosphere interface. For row crops having incomplete canopy cover, the radiometric surface temperature is a composite of sunlit and shaded vegetation and substr...

  8. Radiometric terrain correction of SPOT5 image

    NASA Astrophysics Data System (ADS)

    Feng, Xiuli; Zhang, Feng; Wang, Ke

    2007-06-01

    Remote sensing SPOT5 images have been widely applied to the surveying of agriculture and forest resources and to the monitoring of ecology environment of mountain areas. However, the accuracy of land-cover classification of mountain areas is often influenced by the topographical shadow effect. Radiometric terrain correction is important for this kind of application. In this study, a radiometric terrain correction model which based on the rationale of moment matching was made in ERDAS IMAGINE by using the Spatial Modeler Language. Lanxi city in China as the study area, a SPOT5 multispectral image with the spatial resolution of 10 m of that mountain area was corrected by the model. Furthermore, in order to present the advantage of this new model in radiometric terrain correction of remote sensing SPOT5 image, the traditional C correction approach was also applied to the same area to see its difference with the result of the radiometric terrain correction model. The results show that the C correction approach keeps the overall statistical characteristics of spectral bands. The mean and the standard deviation value of the corrected image are the same as original ones. However, the standard deviation value became smaller by using the radiometric terrain correction model and the mean value changed accordingly. The reason of these changes is that before the correction, the histogram of the original image is represented as the 'plus-skewness distribution' due to the relief-caused shade effect, after the correction of the model, the histogram of the image is represented as the normal distribution and the shade effect of the relief has been removed. But as for the result of the traditional C approach, the skewness of the histogram remains the same after the correction. Besides, some portions of the mountain area have been over-corrected. So in my study area, the C correction approach can't remove the shade effect of the relief ideally. The results show that the radiometric

  9. A radiometric Bode's Law: Predictions for Uranus

    NASA Technical Reports Server (NTRS)

    Desch, M. D.; Kaiser, M. L.

    1984-01-01

    The magnetospheres of three planets, Earth, Jupiter, and Saturn, are known to be sources of intense, nonthermal radio bursts. The emissions from these sources undergo pronounced long term intensity fluctuations that are caused by the solar wind interaction with the magnetosphere of each planet. Determinations by spacecraft of the low frequency radio spectra and radiation beam geometry now permit a reliable assessment of the overall efficiency of the solar wind in stimulating these emissions. Earlier estimates of how magnetospheric radio output scales with the solar wind energy input must be revised greatly, with the result that, while the efficiency is much lower than previously thought, it is remarkably uniform from planet to planet. The formulation of a radiometric Bode's Law from which a planet's magnetic moment is estimated from its radio emission output is presented. Applying the radiometric scaling law to Uranus, the low-frequency radio power is likely to be measured by the Voyager 2 spacecraft as it approaches this planet.

  10. The Candela and Photometric and Radiometric Measurements

    PubMed Central

    Parr, Albert C.

    2001-01-01

    The national measurement system for photometric and radiometric quantities is presently based upon techniques that make these quantities traceable to a high-accuracy cryogenic radiometer. The redefinition of the candela in 1979 provided the opportunity for national measurement laboratories to base their photometric measurements on optical detector technology rather than on the emission from high-temperature blackbody optical sources. The ensuing technical developments of the past 20 years, including the significant improvements in cryogenic radiometer performance, have provided the opportunity to place the fundamental maintenance of photometric quantities upon absolute detector based technology as was allowed by the 1979 redefinition. Additionally, the development of improved photodetectors has had a significant impact on the methodology in most of the radiometric measurement areas. This paper will review the status of the NIST implementation of the technical changes mandated by the 1979 redefinition of the candela and its effect upon the maintenance and dissemination of optical radiation measurements. PMID:27500020

  11. Climate Change and Sounder Radiometric Stability

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Aumann, Hartmut H.; Manning, Evan

    2009-01-01

    Satellite instrument radiometric stability is critical for climate studies. The Atmospheric Infrared Sounder (AIRS) radiances are of sufficient stability and accuracy to serve as a climate data record as evidenced by comparisons with the global network of buoys. In this paper we examine the sensitivity of derived geophysical products to potential instrument radiometric stability issues due to diurnal, orbital and seasonal variations. Our method is to perturb the AIRS radiances and examine the impact to retrieved parameters. Results show that instability in retrieved temperature products will be on the same order of the brightness temperature error in the radiances and follow the same time dependences. AIRS excellent stability makes it ideal for examining impacts of instabilities of future systems on geophysical parameter performance.

  12. Infrared radiometric technique in temperature measurement

    NASA Technical Reports Server (NTRS)

    Glazer, S.; Madding, R.

    1988-01-01

    One class of commercially available imaging infrared radiometers using cooled detectors is sensitive to radiation over the 3 to 12 micron wavelength band. Spectral filters can tailor instrument sensitivity to specific regions where the target exhibits optimum radiance. The broadband spectral response coupled with real time two-dimensional imaging and emittance/background temperature corrections make the instruments useful for remote measurement of surface temperatures from -20 C to +1500 C. Commonly used radiometric techniques and assumptions are discussed, and performance specifications for a typical modern commercial instrument are presented. The potential usefulness of an imaging infrared radiometer in space laboratories is highlighted through examples of research, nondestructive evaluation, safety, and routine maintenance applications. Future improvements in instrument design and application of the radiometric technique are discussed.

  13. Geometric and Radiometric Evaluation of Rasat Images

    NASA Astrophysics Data System (ADS)

    Cam, Ali; Topan, Hüseyin; Oruç, Murat; Özendi, Mustafa; Bayık, Çağlar

    2016-06-01

    RASAT, the second remote sensing satellite of Turkey, was designed and assembled, and also is being operated by TÜBİTAK Uzay (Space) Technologies Research Institute (Ankara). RASAT images in various levels are available free-of-charge via Gezgin portal for Turkish citizens. In this paper, the images in panchromatic (7.5 m GSD) and RGB (15 m GSD) bands in various levels were investigated with respect to its geometric and radiometric characteristics. The first geometric analysis is the estimation of the effective GSD as less than 1 pixel for radiometrically processed level (L1R) of both panchromatic and RGB images. Secondly, 2D georeferencing accuracy is estimated by various non-physical transformation models (similarity, 2D affine, polynomial, affine projection, projective, DLT and GCP based RFM) reaching sub-pixel accuracy using minimum 39 and maximum 52 GCPs. The radiometric characteristics are also investigated for 8 bits, estimating SNR between 21.8-42.2, and noise 0.0-3.5 for panchromatic and MS images for L1R when the sea is masked to obtain the results for land areas. The analysis show that RASAT images satisfies requirements for various applications. The research is carried out in Zonguldak test site which is mountainous and partly covered by dense forest and urban areas.

  14. Revised landsat-5 thematic mapper radiometric calibration

    USGS Publications Warehouse

    Chander, G.; Markham, B.L.; Barsi, J.A.

    2007-01-01

    Effective April 2, 2007, the radiometric calibration of Landsat-5 (L5) Thematic Mapper (TM) data that are processed and distributed by the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) will be updated. The lifetime gain model that was implemented on May 5, 2003, for the reflective bands (1-5, 7) will be replaced by a new lifetime radiometric-calibration curve that is derived from the instrument's response to pseudoinvariant desert sites and from cross calibration with the Landsat-7 (L7) Enhanced TM Plus (ETM+). Although this calibration update applies to all archived and future L5 TM data, the principal improvements in the calibration are for the data acquired during the first eight years of the mission (1984-1991), where the changes in the instrument-gain values are as much as 15%. The radiometric scaling coefficients for bands 1 and 2 for approximately the first eight years of the mission have also been changed. Users will need to apply these new coefficients to convert the calibrated data product digital numbers to radiance. The scaling coefficients for the other bands have not changed. ?? 2007 IEEE.

  15. INTRABAND RADIOMETRIC PERFORMANCE OF THE LANDSAT 4 THEMATIC MAPPER.

    USGS Publications Warehouse

    Kieffer, Hugh H.; Eliason, Eric M.; Chavez, Pat S., Jr.

    1985-01-01

    This preliminary report examines those radiometric characteristics of the Landsat 4 Thematic Mapper (TM) that can be established without absolute calibration of spectral data. Analysis is based largely on radiometrically raw (B type) data of three daytime and two nighttime scenes; in most scenes, a set of 512 lines were examined on an individual-detector basis. Subscenes selected for uniform-radiance were used to characterize subtle radiometric differences and noise problems.

  16. Radiometric instrumentation and measurements guide for photovoltaic performance testing

    SciTech Connect

    Myers, D.

    1997-04-01

    The Photovoltaic Module and Systems Performance and Engineering Project at the National Renewable Energy Laboratory performs indoor and outdoor standardization, testing, and monitoring of the performance of a wide range of photovoltaic (PV) energy conversion devices and systems. The PV Radiometric Measurements and Evaluation Team (PVSRME) within that project is responsible for measurement and characterization of natural and artificial optical radiation which stimulates the PV effect. The PV manufacturing and research and development community often approaches project members for technical information and guidance. A great area of interest is radiometric instrumentation, measurement techniques, and data analysis applied to understanding and improving PV cell, module, and system performance. At the Photovoltaic Radiometric Measurements Workshop conducted by the PVSRME team in July 1995, the need to communicate knowledge of solar and optical radiometric measurements and instrumentation, gained as a result of NREL`s long-term experiences, was identified as an activity that would promote improved measurement processes and measurement quality in the PV research and manufacturing community. The purpose of this document is to address the practical and engineering need to understand optical and solar radiometric instrument performance, selection, calibration, installation, and maintenance applicable to indoor and outdoor radiometric measurements for PV calibration, performance, and testing applications. An introductory section addresses radiometric concepts and definitions. Next, concepts essential to spectral radiometric measurements are discussed. Broadband radiometric instrumentation and measurement concepts are then discussed. Each type of measurement serves as an important component of the PV cell, module, and system performance measurement and characterization process.

  17. Penile Replantation After Five Hours of Warm Ischemia.

    PubMed

    Facio, Fernando N; Spessoto, Luis C; Arruda, Pedro; Paiva, Cristiano S; Arruda, José G; Facio, Maria F

    2015-05-01

    Although a rare occurrence, this event may occur as a result of self-mutilation among individuals with psychiatric disturbances or due to work-related accidents, iatrogenic injuries or the actions of individuals motivated by jealously, rage and feelings of betrayal. In western societies, most penile amputations are the result of self-aggression during a psychotic episode, the treatment of victims involves resuscitation, stabilization and immediate psychiatric support. The amputated tissue must be preserved under hypothermic conditions. Micro-surgery is currently the most widely employed method for penile replantation. This paper describes a successful case of penile replantation following 5 hours of warm ischemia. PMID:26793508

  18. Optical Imaging and Radiometric Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Ha, Kong Q.; Fitzmaurice, Michael W.; Moiser, Gary E.; Howard, Joseph M.; Le, Chi M.

    2010-01-01

    OPTOOL software is a general-purpose optical systems analysis tool that was developed to offer a solution to problems associated with computational programs written for the James Webb Space Telescope optical system. It integrates existing routines into coherent processes, and provides a structure with reusable capabilities that allow additional processes to be quickly developed and integrated. It has an extensive graphical user interface, which makes the tool more intuitive and friendly. OPTOOL is implemented using MATLAB with a Fourier optics-based approach for point spread function (PSF) calculations. It features parametric and Monte Carlo simulation capabilities, and uses a direct integration calculation to permit high spatial sampling of the PSF. Exit pupil optical path difference (OPD) maps can be generated using combinations of Zernike polynomials or shaped power spectral densities. The graphical user interface allows rapid creation of arbitrary pupil geometries, and entry of all other modeling parameters to support basic imaging and radiometric analyses. OPTOOL provides the capability to generate wavefront-error (WFE) maps for arbitrary grid sizes. These maps are 2D arrays containing digital sampled versions of functions ranging from Zernike polynomials to combination of sinusoidal wave functions in 2D, to functions generated from a spatial frequency power spectral distribution (PSD). It also can generate optical transfer functions (OTFs), which are incorporated into the PSF calculation. The user can specify radiometrics for the target and sky background, and key performance parameters for the instrument s focal plane array (FPA). This radiometric and detector model setup is fairly extensive, and includes parameters such as zodiacal background, thermal emission noise, read noise, and dark current. The setup also includes target spectral energy distribution as a function of wavelength for polychromatic sources, detector pixel size, and the FPA s charge

  19. Absolute Radiometric Calibration of KOMPSAT-3A

    NASA Astrophysics Data System (ADS)

    Ahn, H. Y.; Shin, D. Y.; Kim, J. S.; Seo, D. C.; Choi, C. U.

    2016-06-01

    This paper presents a vicarious radiometric calibration of the Korea Multi-Purpose Satellite-3A (KOMPSAT-3A) performed by the Korea Aerospace Research Institute (KARI) and the Pukyong National University Remote Sensing Group (PKNU RSG) in 2015.The primary stages of this study are summarized as follows: (1) A field campaign to determine radiometric calibrated target fields was undertaken in Mongolia and South Korea. Surface reflectance data obtained in the campaign were input to a radiative transfer code that predicted at-sensor radiance. Through this process, equations and parameters were derived for the KOMPSAT-3A sensor to enable the conversion of calibrated DN to physical units, such as at-sensor radiance or TOA reflectance. (2) To validate the absolute calibration coefficients for the KOMPSAT-3A sensor, we performed a radiometric validation with a comparison of KOMPSAT-3A and Landsat-8 TOA reflectance using one of the six PICS (Libya 4). Correlations between top-of-atmosphere (TOA) radiances and the spectral band responses of the KOMPSAT-3A sensors at the Zuunmod, Mongolia and Goheung, South Korea sites were significant for multispectral bands. The average difference in TOA reflectance between KOMPSAT-3A and Landsat-8 image over the Libya 4, Libya site in the red-green-blue (RGB) region was under 3%, whereas in the NIR band, the TOA reflectance of KOMPSAT-3A was lower than the that of Landsat-8 due to the difference in the band passes of two sensors. The KOMPSAT-3Aensor includes a band pass near 940 nm that can be strongly absorbed by water vapor and therefore displayed low reflectance. Toovercome this, we need to undertake a detailed analysis using rescale methods, such as the spectral bandwidth adjustment factor.

  20. An extended area blackbody for radiometric calibration

    NASA Astrophysics Data System (ADS)

    LaVeigne, Joe; Franks, Greg; Singer, Jake; Arenas, D. J.; McHugh, Steve

    2013-06-01

    SBIR is developing an enhanced blackbody for improved radiometric testing. The main feature of the blackbody is an improved coating with higher emissivity than the standard coating used. Comparative measurements of the standard and improved coatings are reported, including reflectance. The coatings were also tested with infrared imagers and a broadband emissivity estimate derived from the imagery data. In addition, a control algorithm for constant slew rate has been implemented, primarily for use in minimum resolvable temperature measurements. The system was tested over a range of slew rates from 0.05 K/min to 10 K/min and its performance reported.

  1. Radiometric stability of Phase 3 WISP arrays

    NASA Astrophysics Data System (ADS)

    Flynn, David S.; Marlow, Steven A.; Bergin, Thomas P.; Murrer, Robert Lee

    2000-07-01

    Phase 3 WISP arrays and BRITE arrays are currently being used extensively in many projection systems in many different facilities. These arrays have not been annealed at the factory, and previous tests with the arrays have revealed instabilities in the radiometric output when the arrays are driven at higher voltages. In some applications, the instabilities can be avoided by operating the arrays at lower voltages. In many KHILS applications, it is desirable to drive the arrays with the highest possible voltages to simulate hot missile targets. In one KHILS application (the KHILS VAcuum Cold Chamber, KVACC), the arrays are cooled to near cryogenic temperatures and then driven to high voltages. At lower substrate temperatures, the characteristic responses of the emitters change. Thus, it is important that the response and the stability of the radiometric output of the arrays be well understood for various substrate temperatures, and that the arrays either be annealed or operated below the voltage where the emitters begin to anneal. KHILS has investigated annealing procedures in the past, but there was concern that the annealing procedures themselves -- driving the arrays at high voltages for long times -- would damage the arrays. In order to understand the performance of the arrays better, and to reduce risks associated with driving the arrays at high voltages and operating the arrays at low substrate temperatures, a systematic measurement program was initiated. The radiometric output of new Phase 3 WISP arrays was accurately measured as a function of voltage and time. Arrays designated for testing were driven to the higher voltages and the radiometric output was measured for as long as two hours. Curves indicative of the annealing were observed, and it was determined that the maximum stable output without annealing was about 500 K (MWIR apparent temperature). Blocks of emitters were annealed and tested again. It was determined that stable output of as much as 680 K

  2. A Multichannel Wide FOV Infrared Radiometric System

    NASA Astrophysics Data System (ADS)

    Jacobson, S.; Lissak, Z.; Yoav, Y.; Komet, Y.; Davidson, R.

    1990-01-01

    A radiometric system which consists of five IR radiometers with a mutual data acquisition system is described. The system was designed, developed and built at IAI to conduct simultaneous IR signature measurements of a high intensity source at different aspect angles. The requirement to provide a wide FOV radiometric capability led to a technical solution based on the combination of refractive and reflective optics. Each radiometer is equipped with a ZnSe lens, elliptical mirror, mechanical chopper and a thermoelectrically cooled PbSe detector. The chopper is positioned before the entrance aperture and its blades serve as an ambient temperature reference Black Body. The reference temperature is monitored by a temperature transducer. The optical layout of the radiometers and relevant ray tracing examples are demonstrated. The radiometer sensitivity and field of view response data are presented. The data acquisition as well as software capabilities are described. The system is remotely operated. Data on source intensity, at different aspect angles, may be obtained immediately after the test.

  3. A multichannel wide FOV infrared radiometric system

    NASA Astrophysics Data System (ADS)

    Jacobson, S.; Lissak, Z.; Yoav, Y.; Komet, Y.; Davidson, R.

    1989-07-01

    A radiometric system which consists of five IR radiometers with a mutual data acquisition system is described. The system was designed, developed and built at IAI to conduct simultaneous IR signature measurements of a high intensity source at different aspect angles. The requirement to provide a wide FOV radiometric capability led to a technical solution based on the combination of refractive and reflective optics. Each radiometer is equipped with a ZnSe lens, elliptical mirror, mechanical chopper and a thermoelectrically cooled PbSe detector. The chopper is positioned before the entrance aperture and its blades serve as an ambient temperature reference Black Body. The reference temperature is monitored by a temperature transducer. The optical layout of the radiometers and relevant ray tracing examples are demonstrated. The radiometer sensitivity and field of view response data are presented. The data acquisition as well as software capabilities are described. The system is remotely operated. Data on source intensity, at different aspect angles, may be obtained immediately after the test.

  4. Radiometric Quality Evaluation of INSAT-3D Imager Data

    NASA Astrophysics Data System (ADS)

    Prakash, S.; Jindal, D.; Badal, N.; Kartikeyan, B.; Gopala Krishna, B.

    2014-11-01

    INSAT-3D is an advanced meteorological satellite of ISRO which acquires imagery in optical and infra-red (IR) channels for study of weather dynamics in Indian sub-continent region. In this paper, methodology of radiometric quality evaluation for Level-1 products of Imager, one of the payloads onboard INSAT-3D, is described. Firstly, overall visual quality of scene in terms of dynamic range, edge sharpness or modulation transfer function (MTF), presence of striping and other image artefacts is computed. Uniform targets in Desert and Sea region are identified for which detailed radiometric performance evaluation for IR channels is carried out. Mean brightness temperature (BT) of targets is computed and validated with independently generated radiometric references. Further, diurnal/seasonal trends in target BT values and radiometric uncertainty or sensor noise are studied. Results of radiometric quality evaluation over duration of eight months (January to August 2014) and comparison of radiometric consistency pre/post yaw flip of satellite are presented. Radiometric Analysis indicates that INSAT-3D images have high contrast (MTF > 0.2) and low striping effects. A bias of <4K is observed in the brightness temperature values of TIR-1 channel measured during January-August 2014 indicating consistent radiometric calibration. Diurnal and seasonal analysis shows that Noise equivalent differential temperature (NEdT) for IR channels is consistent and well within specifications.

  5. Validation of Landsat 7 ETM+ band 6 radiometric performance

    NASA Technical Reports Server (NTRS)

    Palluconi, Frank; Hook, Simon; Abtahi, Ali; Alley, Ron

    2005-01-01

    Since shortly after launch the radiometric performance of band 6 of the ETM+ instrument on Landsat 7 has been evaluated using vicarious calbiration techniques for both land and water targets. This evaluation indicates the radiometric performance of band 6 has been both highly stable and accurate.

  6. Digital correction of geometric and radiometric errors in ERTS data.

    NASA Technical Reports Server (NTRS)

    Bakis, R.; Wesley, M. A.; Will, P. M.

    1971-01-01

    The sensor systems of the ERTS-A satellite are discussed and sources of geometric and radiometric errors in the received images are identified. Digital algorithms are presented for detection of reseau and ground control points, for rapid implementation of geometric corrections, and for radiometric correction of errors caused by shading, image motion, modulation transfer function, and quantum and systematic noise.

  7. Relative radiometric calibration of LANDSAT TM reflective bands

    NASA Technical Reports Server (NTRS)

    Barker, J. L.

    1984-01-01

    A common scientific methodology and terminology is outlined for characterizing the radiometry of both TM sensors. The magnitude of the most significant sources of radiometric variability are discussed and methods are recommended for achieving the exceptional potential inherent in the radiometric precision and accuracy of the TM sensors.

  8. Visible/infrared radiometric calibration station

    SciTech Connect

    Byrd, D.A.; Maier, W.B. II; Bender, S.C.; Holland, R.F.; Michaud, F.D.; Luettgen, A.L.; Christensen, R.W.; O`Brian, T.R.

    1994-07-01

    We have begun construction of a visible/infrared radiometric calibration station that will allow for absolute calibration of optical and IR remote sensing instruments with clear apertures less than 16 inches in diameter in a vacuum environment. The calibration station broadband sources will be calibrated at the National Institute of Standards and Technology (NIST) and allow for traceable absolute radiometric calibration to within {plus_minus}3% in the visible and near IR (0.4--2.5 {mu}m), and less than {plus_minus}1% in the infrared, up to 12 {mu}m. Capabilities for placing diffraction limited images or for sensor full-field flooding will exist. The facility will also include the calibration of polarization and spectral effects, spatial resolution, field of view performance, and wavefront characterization. The configuration of the vacuum calibration station consists of an off-axis 21 inch, f/3.2, parabolic collimator with a scanning fold flat in collimated space. The sources are placed, via mechanisms to be described, at the focal plane of the off-axis parabola. Vacuum system pressure will be in the 10{sup {minus}6} Torr range. The broadband white-light source is a custom design by LANL with guidance from Labsphere Inc. The continuous operating radiance of the integrating sphere will be from 0.0--0.006 W/cm{sup 2}/Sr/{mu}m (upper level quoted for {approximately}500 nm wavelength). The blackbody source is also custom designed at LANL with guidance from NIST. The blackbody temperature will be controllable between 250--350{degrees}K. Both of the above sources have 4.1 inch apertures with estimated radiometric instability at less than 1%. The designs of each of these units will be described. The monochromator and interferometer light sources are outside the vacuum, but all optical relay and beam shaping optics are enclosed within the vacuum calibration station. These sources are described, as well as the methodology for alignment and characterization.

  9. Third comparison of the World Radiometric Reference and the SI radiometric scale

    NASA Astrophysics Data System (ADS)

    Finsterle, W.; Blattner, P.; Moebus, S.; Rüedi, I.; Wehrli, C.; White, M.; Schmutz, W.

    2008-08-01

    Ten years after the last comparison of the World Radiometric Reference (WRR) to the Système International (SI) radiometric scale and in respect of the recent introduction of a quality management system for the maintenance and dissemination of WRR, the need for a third comparison became apparent. In this third comparison, the two scales are related through two separate radiometers representing WRR and two independent realizations of SI by cryogenic radiometers at the Bundesamt für Metrologie (METAS) in Wabern, Switzerland, and at the National Physical Laboratory in Teddington, UK. The final results have confirmed the previously stated agreement between WRR and SI scales to better than 0.03% ± 0.14%.

  10. The Joint African Radiometric Propagation Measurement Programme

    NASA Astrophysics Data System (ADS)

    Arbesser-Rastburg, B.; Zaks, C.; Rogers, D. V.; McCarthy, D. K.; Allnutt, J. E.

    1990-06-01

    This paper summarizes the principal aspects of a major cooperative radiowave propagation experiment that was designed to collect data for improving rain attenuation prediction models for tropical Africa. A pressing need for such data had previously been identified by Resolution 79 of the CCIR. In a unique joint arrangement with three African governments, Intelsat, Comsat, the U.S. Agency for International Development, the U.S. National Telecommunications and Information Administration and the U.S. Telecommunications Training Institute (USTTI) collaborated in setting up a Ku-band radiometric measurement campaign in Cameroon, Kenya and Nigeria. A brief historical overview is given, together with the major technical parameters of the sites and the equipment installed there. The anticipated characteristics of the three locations are outlined with regard to meteorological and propagation conditions, and some preliminary indications of the results are presented based on an inspection of the early event data.

  11. Radiometric consistency assessment of hyperspectral infrared sounders

    NASA Astrophysics Data System (ADS)

    Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

    2015-07-01

    The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark datasets for both inter-calibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and -B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through one year of simultaneous nadir overpass (SNO) observations to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the longwave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both Polar and Tropical SNOs. The combined global SNO datasets indicate that, the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 comparison spectral regions and they range from 0.15 to 0.21 K in the remaining 4 spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

  12. Radiometric consistency assessment of hyperspectral infrared sounders

    NASA Astrophysics Data System (ADS)

    Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

    2015-11-01

    The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark data sets for both intercalibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and MetOp-B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through simultaneous nadir overpass (SNO) observations in 2013, to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the long-wave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both polar and tropical SNOs. The combined global SNO data sets indicate that the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 spectral regions and they range from 0.15 to 0.21 K in the remaining four spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

  13. Laboratory Measurement of Bidirectional Reflectance of Radiometric Tarps

    NASA Technical Reports Server (NTRS)

    Knowlton, Kelly

    2006-01-01

    Objectives: a) To determine the magnitude of radiometric tarp BRDF; b) To determine whether an ASD FieldSpec Pro spectroradiometer can be used to perform the experiment. Radiometric tarps with nominal reflectance values of 52%, 35%, and 3.5%, deployed for IKONOS. QuickBird, and OrbView-3 overpasses Ground-based spectroradiometric measurements of tarp and Spectralon@ panel taken during overpass using ASD FieldSpec Pro spectroradiometer, and tarp reflectance calculated. Reflectance data used in atmospheric radiative transfer model (MODTRAN) to predict satellite at-sensor radiance for radiometric calibration. Reflectance data also used to validate atmospheric correction of high-spatial-resolution multispectral image products

  14. Intraband radiometric performance of the Landsat Thematic Mappers.

    USGS Publications Warehouse

    Kieffer, H.H.; Cook, D.A.; Eliason, E.M.; Eliason, P.T.

    1985-01-01

    Radiometric characteristics have been examined of the Landsat-4 and Landsat-5 Thematic Mappers (TMs) that can be established without absolute calibration of spectral data. This analysis is based on radiometrically and geometrically raw (B-type) data of both uniform (flat-field) and high-contrast scenes. Subscenes selected for uniform radiance were used to characterized subtle radiometric differences and noise problems. Although the general performance of the Thematic Mappers is excellent, various anomalies that have a magnitude of a few digital levels (DN) or less are quantified. -from Authors

  15. Radiometric cloud imaging with an uncooled microbolometer thermal infrared camera.

    PubMed

    Shaw, Joseph; Nugent, Paul; Pust, Nathan; Thurairajah, Brentha; Mizutani, Kohei

    2005-07-25

    An uncooled microbolometer-array thermal infrared camera has been incorporated into a remote sensing system for radiometric sky imaging. The radiometric calibration is validated and improved through direct comparison with spectrally integrated data from the Atmospheric Emitted Radiance Interferometer (AERI). With the improved calibration, the Infrared Cloud Imager (ICI) system routinely obtains sky images with radiometric uncertainty less than 0.5 W/(m(2 )sr) for extended deployments in challenging field environments. We demonstrate the infrared cloud imaging technique with still and time-lapse imagery of clear and cloudy skies, including stratus, cirrus, and wave clouds. PMID:19498585

  16. Radiometric detection of yeasts in blood cultures of cancer patients

    SciTech Connect

    Hopfer, R.L.; Orengo, A.; Chesnut, S.; Wenglar, M.

    1980-09-01

    During a 12-month period, 19,457 blood cultures were collected. Yeasts were isolated from 193 cultures derived from 76 cancer patients. Candida albicans or Candida tropicalis accounted for 79% of isolates. Of the three methods compared, the radiometric method required 2.9 days to become positive, blind subculture required 2.6 days, and Gram stains required 1 day. However, the radiometric method was clearly superior in detecting positive cultures, since 73% of all cultures were first detected radiometrically, 22% were detected by subculture, and only 5% were detected by Gram stain. Although 93% of the isolates were detected by aerobic culture, five (7%) isolates were obtained only from anaerobic cultures. Seven days of incubation appear to be sufficient for the radiometric detection of yeasts.

  17. Laboratory radiometric calibration for the convex grating imaging spectrometer

    NASA Astrophysics Data System (ADS)

    Zhou, Jiankang; Chen, Xinhua; Chen, Yuheng; Ji, Yiqun; Shen, Weimin

    2014-09-01

    The radiometric calibration of imaging spectrometer plays an import role for scientific application of spectral data. The radiometric calibration accuracy is influenced by many factors, such as the stability and uniformity of light source, the transfer precision of radiation standard and so on. But the deviation from the linear response mode and the polarization effect of the imaging spectrometer are always neglected. In this paper, the linear radiometric calibration model is constructed and the radiometric linear response capacity is test by adjusting electric gain, exposure time and radiance level. The linear polarizer and the sine function fitting algorithm are utilized to measure polarization effect. The integrating sphere calibration system is constructed in our Lab and its spectral radiance is calibrated by a well-characterized and extremely stable NIST traceable transfer spectroradiometer. Our manufactured convex grating imaging spectrometer is relative and absolute calibrated based on the integrating sphere calibration system. The relative radiometric calibration data is used to remove or reduce the radiometric response non-uniformity every pixel of imaging spectrometer while the absolute radiometric calibration is used to construct the relationship between the physical radiant of the scene and the digital number of the image. The calibration coefficients are acquired at ten radiance levels. The diffraction noise in the images can be corrected by the calibration coefficients and the uniform radiance image can be got. The calibration result shows that our manufactured imaging spectrometer with convex grating has 3.0% degree of polarization and the uncertainties of the relative and absolute radiometric calibrations are 2.4% and 5.6% respectively.

  18. Radiometric ash monitor with iron compensation

    SciTech Connect

    Bachmann, C.; Erken, M.; Fauth, G.; Kern, H.

    1996-12-31

    The recent development of special devices for the measurement of the coal preparation product`s quality makes it possible to design feed forward and feed back quality control systems. For the determination of the ash content in coal very reliable radiometric measuring devices using the dual energy transmission method are available and well tested since several years. While the devices of the fire generation, where the probes were mounted in the center of the belt, determine the composition of only a part of the material, multi channel systems were developed and installed in preparation plants of different German and foreign mines. These analyzers work with three to five pairs of detectors which are placed across the belt to overcome representativity problems at inhomogeneously loaded belts. Another attempt to overcome those problems is the measurement behind an automatic sampler in a bypass. Dual energy ash meters are well developed and available from different companies round the world. Different examples show that some applications give excellent results while other applications show only poor accuracies due to variations in the composition. A new development using radiation with lower energies to determine important ingredients of coal shows an improvement of the ash measurement. Installed behind a sampler, the system offers a representative measurement which is less dependent on variations of the composition. First results will be presented.

  19. A radiometric assay for HIV-1 protease

    SciTech Connect

    Hyland, L.J.; Dayton, B.D.; Moore, M.L.; Shu, A.Y.; Heys, J.R.; Meek, T.D. )

    1990-08-01

    A rapid, high-throughput radiometric assay for HIV-1 protease has been developed using ion-exchange chromatography performed in 96-well filtration plates. The assay monitors the activity of the HIV-1 protease on the radiolabeled form of a heptapeptide substrate, (tyrosyl-3,5-3H)Ac-Ser-Gln-Asn-Tyr-Pro-Val-Val-NH2, which is based on the p17-p24 cleavage site found in the viral polyprotein substrate Pr55gag. Specific cleavage of this uncharged heptapeptide substrate by HIV-1 protease releases the anionic product (tyrosyl-3,5-3H)Ac-Ser-Gln-Asn-Tyr, which is retained upon minicolumns of the anion-exchange resin AG1-X8. Protease activity is determined from the recovery of this radiolabeled product following elution with formic acid. This facile and highly sensitive assay may be utilized for steady-state kinetic analysis of the protease, for measurements of enzyme activity during its purification, and as a routine assay for the evaluation of protease inhibitors from natural product or synthetic sources.

  20. Radiometric Meteorology: radon progeny as tracers

    NASA Astrophysics Data System (ADS)

    Greenfield, Mark; Iwata, Atsushi; Ito, Nahoko; Kubo, Kenya; Komura, Kazu; Ishizaki, Miho

    2008-10-01

    In-situ measurement of atmospheric γ radiation from radon progeny determine rain and snow rates to better accuracy than standard rain gauges and gives a handle on how droplets are formed. The measured γ ray rates (GRR) have been shown to be proportional to a power of radiometric precipitation rates (RPR)^α, α giving a handle on the extent to which radon progeny are surface adsorbed or volume absorbed.ootnotetextM. B. Greenfield et al., J. Appl. Phys. 93, (2003) pp 5733-5741. More recently time dependent ratios of GRR from ^214Pb and ^214Bi, concentrated from collected rainwater, have been used to determine the elapsed time since activity from RPR, adhered to rain droplets, was removed from secular equilibrium. Ion exchange resins precipitate out the ^214Pb and ^214Bi ions, which are then filtered from 10s of liters of rainwater or snowmelt. A portable Ge detector is used to integrate the resulting activity over 5-10 min intervals. The measured evolution of these two activities from secular equilibrium to transient equilibrium has meteorological applications enabling both the determination of average elapsed times between the formation of raindrops and the time they reach the ground, as well as an estimate of the initial activity at the source of droplet formation.

  1. Lessons Learned from the AIRS Pre-Flight Radiometric Calibration

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Aumann, Hartmut H.; Weiler, Margie

    2013-01-01

    The Atmospheric Infrared Sounder (AIRS) instrument flies on the NASA Aqua satellite and measures the upwelling hyperspectral earth radiance in the spectral range of 3.7-15.4 micron with a nominal ground resolution at nadir of 13.5 km. The AIRS spectra are achieved using a temperature controlled grating spectrometer and HgCdTe infrared linear arrays providing 2378 channels with a nominal spectral resolution of approximately 1200. The AIRS pre-flight tests that impact the radiometric calibration include a full system radiometric response (linearity), polarization response, and response vs scan angle (RVS). We re-derive the AIRS instrument radiometric calibration coefficients from the pre-flight polarization measurements, the response vs scan (RVS) angle tests as well as the linearity tests, and a recent lunar roll test that allowed the AIRS to view the moon. The data and method for deriving the coefficients is discussed in detail and the resulting values compared amongst the different tests. Finally, we examine the residual errors in the reconstruction of the external calibrator blackbody radiances and the efficacy of a new radiometric uncertainty model. Results show the radiometric calibration of AIRS to be excellent and the radiometric uncertainty model does a reasonable job of characterizing the errors.

  2. Radiometric calibration of the EO-1 Advanced Land Imager

    NASA Astrophysics Data System (ADS)

    Mendenhall, Jeffrey A.; Lencioni, Donald E.; Parker, Alexander C.

    1999-09-01

    The radiometric calibration of the Earth Observation 1 Advanced Land Imager (EO-1 ALI) was completed in the Spring of 1999 at Lincoln Laboratory. This calibration was conducted with the ALI as a fully assembled instrument in a thermal vacuum chamber at operation temperatures. The ALI was calibrated radiometrically at the system level from 0 to > 100 percent Earth-equivalent albedo using a combination of internal and external halogen and Xenon lamps attached to a large integrating sphere. Absolute radiometric calibration was achieved by measuring the output of the integrating sphere at each radiance level prior to ALI illumination using a NIST-traceable spectroradiometer. Additional radiometric characterization of this instrument was obtained from data collected using a collimator designed for the spectral calibration of the ALI. In this paper we review the techniques employed during radiometric calibration and present the measured gain, linearity, offset, signal-to- noise ratio and polarization sensitivity of each pixel. The testing result of a novel, in-flight solar calibration technique are also discussed. Finally, the results from a Lincoln Laboratory/Goddard Space Flight Center Landsat transfer radiometric study are presented.

  3. Radiometric Characteristics of Cassini RADAR Imagery

    NASA Astrophysics Data System (ADS)

    Stiles, B. W.; Gim, Y.; Hamilton, G. A.; Johnson, W. T.; Shimada, J. G.; West, R. D.

    2004-12-01

    The Cassini RADAR instrument on-board the Cassini Orbiter is currently being employed to obtain SAR imagery of the surface of Saturn's largest moon, Titan. The viewing geometry of Cassini RADAR is different from most imaging radars because the Cassini Orbiter flies by Titan rather than entering into orbit about it. This unusual viewing geometry leads to variable noise characteristics throughout the SAR swath. Due to large changes in range to target and number of looks, noise characteristics and effective resolution vary widely throughout the swath. A good understanding of these parameters is important in order to draw scientific conclusions from the SAR images. Changes in noise bias could be misinterpreted as changes in reflectivity from the surface. Changes in resolution or noise variance could be misinterpreted as changes in the heterogeneity of the surface. The purpose of this paper is to quantify noise variance, bias, and effective radiometric resolution throughout the SAR swath in order to aid scientists in interpreting the data. Of the three parameters, the easiest to model is noise bias which increases with the range to the target. Noise variance is more complicated. The thermal noise (SNR) contribution to the overall variance increases with range, but the fading (speckle) noise contribution varies inversely with number of looks and thus with range. Effective resolution becomes coarser as range increases, but cross track and along track resolution vary differently. Along track resolution varies continuously, but cross track resolution has a discontinuity at 1600 km altitude, due to a change in commanded bandwidth. This paper presents the equations governing the noise characteristics and effective resolution as well as providing pseudo-color images of each quantity in SAR image coordinates for the October 2004 Cassini RADAR observation of Titan. This work was performed at the Jet Propulsion Laboratory, California Institute of Technology under contract with

  4. Assessment of VIIRS radiometric performance using vicarious calibration sites

    NASA Astrophysics Data System (ADS)

    Uprety, Sirish; Cao, Changyong; Blonski, Slawomir; Wang, Wenhui

    2014-09-01

    Radiometric performance of satellite instruments needs to be regularly monitored to determine if there is any drift in the instrument response over time despite the calibration with the best effort. If a drift occurs, it needs to be characterized in order to keep the radiometric accuracy and stability well within the specification. Instrument gain change over time can be validated independently using many techniques such as using stable earth targets (desert, ocean, snow sites etc), inter-comparison with other well calibrated radiometers (using SNO, SNO-x), deep convective clouds (DCC), lunar observations or other methods. This study focus on using vicarious calibration sites for the assessment of radiometric performance of Suomi National Polar-Orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) reflective solar bands. The calibration stability is primarily analyzed by developing the top-of-atmosphere (TOA) reflectance time series over these sites. In addition, the radiometric bias relative to AQUA MODIS is estimated over these calibration sites and analyzed. The radiometric bias is quantified in terms of observed and spectral bias. The spectral characterization and bias analysis will be performed using hyperspectral measurements and radiative transfer models such as MODTRAN.

  5. Fundus image change analysis: geometric and radiometric normalization

    NASA Astrophysics Data System (ADS)

    Shin, David S.; Kaiser, Richard S.; Lee, Michael S.; Berger, Jeffrey W.

    1999-06-01

    Image change analysis will potentiate fundus feature quantitation in natural history and intervention studies for major blinding diseases such as age-related macular degeneration and diabetic retinopathy. Geometric and radiometric normalization of fundus images acquired at two points in time are required for accurate change detection, but existing methods are unsatisfactory for change analysis. We have developed and explored algorithms for correction of image misalignment (geometric) and inter- and intra-image brightness variation (radiometric) in order to facilitate highly accurate change detection. Thirty-five millimeter color fundus photographs were digitized at 500 to 1000 dpi. Custom-developed registration algorithms correcting for translation only; translation and rotation; translation, rotation, and scale; and polynomial based image-warping algorithms allowed for exploration of registration accuracy required for change detection. Registration accuracy beyond that offered by rigid body transformation is required for accurate change detection. Radiometric correction required shade-correction and normalization of inter-image statistical parameters. Precise geometric and radiometric normalization allows for highly accurate change detection. To our knowledge, these results are the first demonstration of the combination of geometric and radiometric normalization offering sufficient accuracy to allow for accurate fundus image change detection potentiating longitudinal study of retinal disease.

  6. Radiometric Study of Soil Profiles in the Infrared Band

    NASA Astrophysics Data System (ADS)

    Ponomareva, T. V.; Ponomarev, E. I.

    2016-02-01

    The applicability of radiometric survey of soil profiles in the infrared range for the analysis of soil physical properties was studied. Radiometric data were obtained for different dates of the growing season for a number of soil profiles. The specificity of temperature profiles of texture-differentiated soils (Luvisols and Retisols) as related to weather conditions of the growing season was examined. The correlation analysis showed a close relationship between the air and surface soil temperatures and between the radiometric and thermodynamic soil temperatures in the upper 10 cm. In the studied profiles, the gradient of radiometric temperatures reached 0.5-0.8°C/cm in the humus horizons and sharply decreased at the depth of more than 15-20 cm. The gradient analysis of radiometric images made it possible to outline the boundaries of soil horizons. For the texture-differentiated soils, the most distinct boundaries were established between the gray-humus AY horizon and the underlying eluvial EL horizon in podzolic soils and between the AY horizon and the underlying humus-eluvial AEL horizon in gray soils.

  7. Deep Space Network Radiometric Remote Sensing Program

    NASA Technical Reports Server (NTRS)

    Walter, Steven J.

    1994-01-01

    Planetary spacecraft are viewed through a troposphere that absorbs and delays radio signals propagating through it. Tropospheric water, in the form of vapor, cloud liquid, and precipitation, emits radio noise which limits satellite telemetry communication link performance. Even at X-band, rain storms have severely affected several satellite experiments including a planetary encounter. The problem will worsen with DSN implementation of Ka-band because communication link budgets will be dominated by tropospheric conditions. Troposphere-induced propagation delays currently limit VLBI accuracy and are significant sources of error for Doppler tracking. Additionally, the success of radio science programs such as satellite gravity wave experiments and atmospheric occultation experiments depends on minimizing the effect of water vapor-induced propagation delays. In order to overcome limitations imposed by the troposphere, the Deep Space Network has supported a program of radiometric remote sensing. Currently, water vapor radiometers (WVRs) and microwave temperature profilers (MTPs) support many aspects of the Deep Space Network operations and research and development programs. Their capability to sense atmospheric water, microwave sky brightness, and atmospheric temperature is critical to development of Ka-band telemetry systems, communication link models, VLBI, satellite gravity wave experiments, and radio science missions. During 1993, WVRs provided data for propagation model development, supported planetary missions, and demonstrated advanced tracking capability. Collection of atmospheric statistics is necessary to model and predict performance of Ka-band telemetry links, antenna arrays, and radio science experiments. Since the spectrum of weather variations has power at very long time scales, atmospheric measurements have been requested for periods ranging from one year to a decade at each DSN site. The resulting database would provide reliable statistics on daily

  8. In-flight Absolute Radiometric Calibration of the Thematic Mapper

    NASA Technical Reports Server (NTRS)

    Castle, K. R.; Holm, R. G.; Kastner, C. J.; Palmer, J. M.; Slater, P. N.; Dinguirard, M.; Ezra, C. E.; Jackson, D.; Savage, R. K.

    1984-01-01

    The Thematic Mapper (TM) multispectral scanner system was placed into Earth orbit on July 16, 1982, as part of NASA's LANDSAT 4 payload. To determine temporal changes of the absolute radiometric calibration of the entire system in flight, spectroradiometric measurements of the ground and the atmosphere are made simultaneously with TM image acquisitions over the White Sands, New Mexico area. By entering the measured values into an atmospheric radiative transfer program, the radiance levels at the entrance pupil of the TM in four of the TM spectral bands are determined. These levels are compared to the output digital counts from the detectors that sampled the radiometrically measured ground area, thus providing an absolute radiometric calibration of the entire TM system utilizing those detectors. By reference to an adjacent, larger uniform area, the calibration is extended to all 16 detectors in each of the three bands.

  9. In-flight absolute radiometric calibration of the thematic mapper

    NASA Technical Reports Server (NTRS)

    Castle, K. R.; Holm, R. G.; Kastner, C. J.; Palmer, J. M.; Slater, P. N.; Dinguirard, M.; Ezra, C. E.; Jackson, R. D.; Savage, R. K.

    1984-01-01

    In order to determine temporal changes of the absolute radiometric calibration of the entire TM system in flight spectroradiometric measurements of the ground and the atmosphere were made simultaneously with TM image collections over the White Sands, New Mexico area. By entering the measured values in an atmospheric radiative transfer program, the radiance levels in four of the spectral bands of the TM were determined, band 1:0.45 to 0.52 micrometers, band 2:0.53 to 0.61 micrometers band 3:0.62 to 0.70 micrometers and 4:0.78 to 0.91 micrometers. These levels were compared to the output digital counts from the detectors that sampled the radiometrically measured ground area, thus providing an absolute radiometric calibration of the entire TM system utilizing those detectors.

  10. In-flight absolute radiometric calibration of the Thematic Mapper

    NASA Technical Reports Server (NTRS)

    Castle, K. R.; Holm, R. G.; Kastner, C. J.; Palmer, J. M.; Slater, P. N.; Dinguirard, M.; Ezra, C. E.; Jackson, R. D.; Savage, R. K.

    1984-01-01

    In order to determine temporal changes of the absolute radiometric calibration of the entire TM system in flight spectroradiometric measurements of the ground and the atmosphere were made simultaneously with TM image collections over the White Sands, NM area. By entering the measured values in an atmospheric radiative transfer program, the radiance levels in four of the spectral bands of the TM were determined, band 1: 0.45 to 0.52 micrometers, band 2: 0.53 to 0.61 micrometers, band 3: 0.62 to 0.70 micrometers, and 4: 0.78 to 0.91 micrometers. These levels were compared to the output digital counts from the detectors that sampled the radiometrically measured ground area, thus providing an absolute radiometric calibration of the entire TM system utilizing those detectors. Previously announced in STAR as N84-15633

  11. Landsat-5 TM reflective-band absolute radiometric calibration

    USGS Publications Warehouse

    Chander, G.; Helder, D.L.; Markham, B.L.; Dewald, J.D.; Kaita, E.; Thome, K.J.; Micijevic, E.; Ruggles, T.A.

    2004-01-01

    The Landsat-5 Thematic Mapper (TM) sensor provides the longest running continuous dataset of moderate spatial resolution remote sensing imagery, dating back to its launch in March 1984. Historically, the radiometric calibration procedure for this imagery used the instrument's response to the Internal Calibrator (IC) on a scene-by-scene basis to determine the gain and offset of each detector. Due to observed degradations in the IC, a new procedure was implemented for U.S.-processed data in May 2003. This new calibration procedure is based on a lifetime radiometric calibration model for the instrument's reflective bands (1-5 and 7) and is derived, in part, from the IC response without the related degradation effects and is tied to the cross calibration with the Landsat-7 Enhanced Thematic Mapper Plus. Reflective-band absolute radiometric accuracy of the instrument tends to be on the order of 7% to 10%, based on a variety of calibration methods.

  12. The two faces of Iapetus. [photometric and radiometric albedo observations

    NASA Technical Reports Server (NTRS)

    Morrison, D.; Jones, T. J.; Cruikshank, D. P.; Murphy, R. E.

    1975-01-01

    Radiometric and photometric observations of Iapetus are described, and a model is developed for the albedo distribution consistent with the visual light curves, color variations, and radiometric flux curve. The 20-micron infrared observations show that the radiometric variation differs by about 180 deg in phase from the visual light curve and has a peak-to-peak amplitude of about a factor of two, while the linear phase coefficient of the light curve varies, as the satellite rotates, from 0.028 to 0.068 mag/deg. Determination of the albedo distribution is described, and it is found to be characterized by a dark area covering most of the leading hemisphere, a bright trailing hemisphere, and a bright south polar cap. The radius is approximated as 800 to 850 km, and the mean geometric albedos for the light and dark faces are estimated as 0.35 and 0.07, respectively.

  13. Radiometric correction of SAR images of varying terrain heights

    NASA Technical Reports Server (NTRS)

    Freeman, A.; Moghaddam, M.; Zink, M.; Zebker, H.

    1992-01-01

    The advantages and disadvantages of three different approaches to solving the problem of the radiometric correction of synthetic aperture radar (SAR) images of varying terrain heights are presented. The first approach involves registration of a digital elevation model (DEM) of the terrain to the image, determination of the local elevation and incidence angles, and appropriate radiometric correction. The second approach uses a DEM generated from interferometric SAR data to derive the elevation and incidence angle maps. In the third approach, a monopulse technique is employed to determine the elevation angle only. The relative errors in radiometric correction between these approaches are assessed. Calibration errors are estimated using corner reflectors deployed within some of the scenes imaged by the Jet Propulsion Laboratory airborne SAR (JPL AIRSAR).

  14. Spectral, spatial and radiometric factors in cover type discrimination

    NASA Technical Reports Server (NTRS)

    Alexander, D.; Buis, J.; Acevedo, W.; Wrigley, R.

    1983-01-01

    The influence of spatial, spectral, and radiometric resolutions on the utilization of Thematic Mapper (TM) and Multispectral Scanner (MSS) data is assessed quantitatively using a 2 x 2 x 2 factorial design experiment. Eight possible factor combinations were examined for agricultural, urban, forestry, range, and water types of land covers for three levels of information. Spectral bandwidths were configured to simulate all four Landsat MSS channels and Landsat TM channels 1, 2, 3, 4, and 7. By means of bar charts and tables it is shown that the 8-bit radiometric and 75-meter spatial resolutions provide a higher overall accuracy than the 6-bit radiometric and 25-meter spatial resolutions. Spectrally, the difference between the four MSS channels and five TM channel configurations is noted to be insignificant.

  15. On-orbit radiometric calibration of Earth-observing sensors using the Radiometric Calibration Test Site (RadCaTS)

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, Jeffrey S.; Leisso, Nathan P.; Anderson, Nikolaus J.; Biggar, Stuart F.

    2012-06-01

    Vicarious techniques are used to provide supplemental radiometric calibration data for sensors with onboard calibration systems, and are increasingly important for sensors without onboard calibration systems. The Radiometric Calibration Test Site (RadCaTS) is located at Railroad Valley, Nevada. It is a facility that was developed with the goal of increasing the amount of ground-based radiometric calibration data that are collected annually while maintaining the current level of radiometric accuracy produced by traditional manned field campaigns. RadCaTS is based on the reflectance-based approach, and currently consists of a Cimel sun photometer to measure the atmosphere, a weather station to monitor meteorological conditions, and ground-viewing radiometers (GVRs) that are used the determine the surface reflectance throughout the 1 × 1-km area. The data from these instruments are used in MODTRAN5 to determine the at-sensor spectral radiance at the time of overpass. This work describes the RadCaTS concept, the instruments used to obtain the data, and the processing method used to determine the surface reflectance and top-of-atmosphere spectral radiance. A discussion on the design and calibration of three new eight-channel GVRs is introduced, and the surface reflectance retrievals are compared to in situ measurements. Radiometric calibration results determined using RadCaTS are compared to Landsat 7 ETM+, MODIS, and MISR.

  16. Hybridization behavior of mixed DNA/alkylthiol monolayers on gold: characterization by surface plasmon resonance and 32P radiometric assay.

    PubMed

    Gong, Ping; Lee, Chi-Ying; Gamble, Lara J; Castner, David G; Grainger, David W

    2006-05-15

    Nucleic acid assay from a complex biological milieu is attractive but currently difficult and far from routine. In this study, DNA hybridization from serum dilutions into mixed DNA/mercaptoundecanol (MCU) adlayers on gold was monitored by surface plasmon resonance (SPR). Immobilized DNA probe and hybridized target densities on these surfaces were quantified using 32P-radiometric assays as a function of MCU diluent exposure. SPR surface capture results correlated with radiometric analysis for hybridization performance, demonstrating a maximum DNA hybridization on DNA/MCU mixed adlayers. The maximum target surface capture produced by MCU addition to the DNA probe layer correlates with structural and conformational data on identical mixed DNA/MCU adlayers on gold derived from XPS, NEXAFS, and fluorescence intensity measurements reported in a related study (Lee, C.-Y.; Gong, P.; Harbers, G. M.; Grainger, D. W.; Castner, D. G.; Gamble, L. J. Anal. Chem. 2006, 78, 3316-3325.). MCU addition into the DNA adlayer on gold also improved surface resistance to both nonspecific DNA and serum protein adsorption. Target DNA hybridization from serum dilutions was monitored with SPR on the optimally mixed DNA/MCU adlayers. Both hybridization kinetics and efficiency were strongly affected by nonspecific protein adsorption from a complex milieu even at a minimal serum concentration (e.g., 1%). No target hybridization was detected in SPR assays from serum concentrations above 30%, indicating nonspecific protein adsorption interference of DNA capture and hybridization from complex milieu. Removal of nonsignal proteins from nucleic acid targets prior to assay represents a significant issue for direct sample-to-assay nucleic acid diagnostics from food, blood, tissue, PCR mixtures, and many other biologically complex sample formats. PMID:16689533

  17. JACIE Radiometric Assessment of QuickBird Multispectral Imagery

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Carver, David; Holekamp, Kara; Knowlton, Kelly; Ryan, Robert; Zanoni, Vicki; Thome, Kurtis; Aaron, David

    2004-01-01

    Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities can place confidence in the imagery they use and can fully understand its properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other systems. To address this calibration need, the NASA Stennis Space Center (SSC) Earth Science Applications (ESA) directorate,through the Joint Agency for Commercial Imagery Evaluation (JACIE) framework, established a commercial imaging satellite radiometric calibration team consisting of two groups: 1) NASA SSC ESA, supported by South Dakota State University, and 2) the University of Arizona Remote Sensing Group. The two groups determined the absolute radiometric calibration coefficients of the Digital Globe 4-band, 2.4-m QuickBird multispectral product covering the visible through near-infrared spectral region. For a 2-year period beginning in 2002, both groups employed some variant of a reflectance-based vicarious calibration approach, which required ground-based measurements coincident with QuickBird image acquisitions and radiative transfer calculations. The groups chose several study sites throughout the United States that covered nearly the entire dynamic range of the QuickBird sensor. QuickBird at-sensor radiance values were compared with those estimated by the two independent groups to determine the QuickBird sensor's radiometric accuracy. Approximately 20 at-sensor radiance estimates were vicariously determined each year. The estimates were combined to provide a high-precision radiometric gain calibration coefficient. The results of this evaluation provide the user community with an independent assessment of the QuickBird sensor's absolute calibration and stability over the 2-year period. While the techniques and method described reflect those developed at the NASA SSC, the results of both JACIE team groups are

  18. Calibration of the radiometric asteroid scale using occultation diameters

    NASA Technical Reports Server (NTRS)

    Telesco, C. M.; Brunk, W. E.; Brown, R. H.; Morrison, D.

    1982-01-01

    The paper describes a new approach to the calibration of the radiometric asteroid scale, which relies on recent accurate occultation measurements of the diameters of 2 Pallas (Wasserman et al., 1979) and 3 Juno (Millis et al., 1981), and the Voyager diameter of J4 Callisto, as well as IR photometry of these objects obtained with the NASA 3-m Infrared Telescope Facility. It is shown that this calibration is internally consistent to better than 5%, and probably has an absolute accuracy of + or - 5%. It is noted that a revision of the TRIAD radiometric diameters downward is required to bring them into agreement with the new calibration.

  19. Sentinel-3 OLCI Radiometric and Spectral Performance Activities

    NASA Astrophysics Data System (ADS)

    Bourg, L.; Blanot, L.; Lamquin, N.; Bruniquel, V.; Meskini, N.; Nieke, J.; Bouvet, M.; Fougnie, B.

    2015-12-01

    The paper presents the activities to be undertaken by ACRI-ST under ESA/ESTEC coordination for the assessment of OLCI Radiometric and Spectral Performances during the SENTINEL-3 Commissioning Phase. As an introduction, it briefly describes the instrument concept and available on-board calibration hardware, the context and main objective of the work. Insisting on the fact that radiometric calibration of OLCI is based on in-flight measurements, as was for MERIS, it then describes the methodology and tools to be used during Commissioning. Finally, as in-flight based radiometry implies the need for independent validation, it describes the corresponding methods and tools.

  20. Prelaunch absolute radiometric calibration of LANDSAT-4 protoflight Thematic Mapper

    NASA Technical Reports Server (NTRS)

    Barker, J. L.; Ball, D. L.; Leung, K. C.; Walker, J. A.

    1984-01-01

    Results are summarized and analyzed from several prelaunch tests with a 122 cm integrating sphere used as part of the absolute radiometric calibration experiments for the protoflight TM sensor carried on the LANDSAT-4 satellite. The calibration procedure is presented and the radiometric sensitivity of the TM is assessed. The internal calibrator and dynamic range after calibration are considered. Tables show dynamic range after ground processing, spectral radiance to digital number and digital number to spectral radiance values for TM bands 1, 2, 3, 4, 5, 7 and for channel 4 of band 6.

  1. Research radiometric calibration quantitative transfer methods between internal and external

    NASA Astrophysics Data System (ADS)

    Guo, Ju Guang; Ma, Yong hui; Zhang, Guang; Yang, Zhi hui

    2015-10-01

    This paper puts forward a method by realizing the internal and external radiation calibration transfer for infrared radiation characteristics quantitative measuring system. Through technological innovation and innovation application to establish a theoretical model of the corresponding radiated transfer method. This method can be well in engineering application for technology conversion process of radiometric calibration that with relatively simple and effective calibration in the half light path radiation instead of complex difficult whole optical path radiometric calibration. At the same time, it also will provide the basis of effective support to further carry out the target radiated characteristics quantitative measurement and application for ground type infrared radiated quantitative measuring system.

  2. Serum sickness

    MedlinePlus

    ... passive immunization. It gives you immediate, but temporary, protection while your body develops an active immune response against the toxin or germ. During serum sickness, the immune system falsely identifies a protein in antiserum as a ...

  3. Pleiades-Hr Innovative Techniques for Radiometric Image Quality Commissioning

    NASA Astrophysics Data System (ADS)

    Blanchet, G.; Lebeque, L.; Fourest, S.; Latry, C.; Porez-Nadal, F.; Lacherade, S.; Thiebaut, C.

    2012-07-01

    The first Pleiades-HR satellite, part of a constellation of two, has been launched on December 17, 2011. This satellite produces high resolution optical images. In order to achieve good image quality, Pleiades-HR should first undergo an important 6 month commissioning phase period. This phase consists in calibrating and assessing the radiometric and geometric image quality to offer the best images to end users. This new satellite has benefited from technology improvements in various fields which make it stand out from other Earth observation satellites. In particular, its best-in-class agility performance enables new calibration and assessment techniques. This paper is dedicated to presenting these innovative techniques that have been tested for the first time for the Pleiades- HR radiometric commissioning. Radiometric activities concern compression, absolute calibration, detector normalization, and refocusing operations, MTF (Modulation Transfer Function) assessment, signal-to-noise ratio (SNR) estimation, and tuning of the ground processing parameters. The radiometric performances of each activity are summarized in this paper.

  4. Radiometric Calibration of Osmi Imagery Using Solar Calibration

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Han; Kim, Yong-Seung

    2000-12-01

    OSMI (Ocean Scanning Multi-Spectral Imager) raw image data (Level 0) were acquired and radiometrically corrected. We have applied two methods, using solar & dark calibration data from OSMI sensor and comparing with the SeaWiFS data, to the radiometric correction of OSMI raw image data. First, we could get the values of the gain and the offset for each pixel and each band from comparing the solar & dark calibration data with the solar input radiance values, calculated from the transmittance, BRDF (Bidirectional Reflectance Distribution Function) and the solar incidence angle (¥â,¥è) of OSMI sensor. Applying this calibration data to OSMI raw image data, we got the two odd results, the lower value of the radiometric corrected image data than the expected value, and the Venetian Blind Effect in the radiometric corrected image data. Second, we could get the reasonable results from comparing OSMI raw image data with the SeaWiFS data, and get a new problem of OSMI sensor.

  5. A preliminary study of a very large space radiometric antenna

    NASA Technical Reports Server (NTRS)

    Agrawal, P. K.

    1979-01-01

    An approach used to compute the size of a special radiometric reflector antenna is presented. Operating at 1 GHz, this reflector is required to produce 200 simultaneous contiguous beams, each with a 3 dB footprint of 1 km from an assumed satellite height of 650 km. The overall beam efficiency for each beam is required to be more than 90%.

  6. A Review of LIDAR Radiometric Processing: From Ad Hoc Intensity Correction to Rigorous Radiometric Calibration

    PubMed Central

    Kashani, Alireza G.; Olsen, Michael J.; Parrish, Christopher E.; Wilson, Nicholas

    2015-01-01

    In addition to precise 3D coordinates, most light detection and ranging (LIDAR) systems also record “intensity”, loosely defined as the strength of the backscattered echo for each measured point. To date, LIDAR intensity data have proven beneficial in a wide range of applications because they are related to surface parameters, such as reflectance. While numerous procedures have been introduced in the scientific literature, and even commercial software, to enhance the utility of intensity data through a variety of “normalization”, “correction”, or “calibration” techniques, the current situation is complicated by a lack of standardization, as well as confusing, inconsistent use of terminology. In this paper, we first provide an overview of basic principles of LIDAR intensity measurements and applications utilizing intensity information from terrestrial, airborne topographic, and airborne bathymetric LIDAR. Next, we review effective parameters on intensity measurements, basic theory, and current intensity processing methods. We define terminology adopted from the most commonly-used conventions based on a review of current literature. Finally, we identify topics in need of further research. Ultimately, the presented information helps lay the foundation for future standards and specifications for LIDAR radiometric calibration. PMID:26561813

  7. A Review of LIDAR Radiometric Processing: From Ad Hoc Intensity Correction to Rigorous Radiometric Calibration.

    PubMed

    Kashani, Alireza G; Olsen, Michael J; Parrish, Christopher E; Wilson, Nicholas

    2015-01-01

    In addition to precise 3D coordinates, most light detection and ranging (LIDAR) systems also record "intensity", loosely defined as the strength of the backscattered echo for each measured point. To date, LIDAR intensity data have proven beneficial in a wide range of applications because they are related to surface parameters, such as reflectance. While numerous procedures have been introduced in the scientific literature, and even commercial software, to enhance the utility of intensity data through a variety of "normalization", "correction", or "calibration" techniques, the current situation is complicated by a lack of standardization, as well as confusing, inconsistent use of terminology. In this paper, we first provide an overview of basic principles of LIDAR intensity measurements and applications utilizing intensity information from terrestrial, airborne topographic, and airborne bathymetric LIDAR. Next, we review effective parameters on intensity measurements, basic theory, and current intensity processing methods. We define terminology adopted from the most commonly-used conventions based on a review of current literature. Finally, we identify topics in need of further research. Ultimately, the presented information helps lay the foundation for future standards and specifications for LIDAR radiometric calibration. PMID:26561813

  8. Radiometric Calibration of Earth-Observing Sensors Using the Radiometric Calibration Test Site (RadCaTS)

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, J.; Anderson, N. J.; Thome, K. J.; Biggar, S. F.

    2014-12-01

    The Remote Sensing Group (RSG) of the College of Optical Sciences at the University of Arizona uses the reflectance-based approach to perform the absolute radiometric calibration of such sensors as Landsat 5 TM, Landsat 7 ETM+, Landsat 8 OLI, Terra and Aqua MODIS, ASTER, RapidEye, and others. The reflectance-based approach requires that personnel be present at a test site during the sensor overpass, so the Radiometric Calibration Test Site (RadCaTS) was developed in order to capture data during every possible overpass, which assists in the temporal trending of the radiometric calibration of earth-observing sensors. The number of earth-observing sensors is rapidly increasing in recent years, and RadCaTS provides the ability to radiometrically calibrate them without the requirement of frequent field campaigns. The 2013 launch of Landsat 8 provides a unique opportunity for RadCaTS in that it is being used to supplement the in situ measurements by RSG ground personnel, and it will be used throughout the lifetime of the Landsat 8 mission. This allows more data to be collected throughout the year, and it also allows the accuracy and uncertainty of RadCaTS to be analyzed. The current top-of-atmosphere (TOA) spectral radiance uncertainty of the reflectance-based approach is ~2.6% in the mid-visible region of the spectrum, and current work indicates that the uncertainty of RadCaTS in TOA spectral radiance is ~3-4%. This work presents the radiometric calibration results of RadCaTS for a variety of sensors such as Landsat 7 ETM+, Landsat 8 OLI, Terra and Aqua MODIS, MISR, ASTER, and Suomi NPP VIIRS.

  9. The 90 GHz radiometric imaging. [for terrain analysis

    NASA Technical Reports Server (NTRS)

    King, H. E.; White, J. D.; Wilson, W. J.; Mori, T. T.; Hollinger, J. P.; Troy, B. E.; Kenney, J. E.; Mcgoogan, J. T.

    1976-01-01

    A 90-GHz (3 mm wavelength) radiometer with a noise output fluctuation of 0.22 K (RMS), with a scanning antenna beam mirror, and the data processing system are described. Real-time radiometric imaging of terrain and man-made objects are shown. Flying at an altitude of 1500 ft a radiometer antenna with a 2 degrees halfpower beamwidth can distinguish landforms, waterways, roads, runways, bridges, ships at sea and their wakes, aircraft on runways, and athletic fields. A flight taken at an altitude of 3000 ft with approximately 2000 ft of clouds below the radiometer demonstrates the ability to distinguish bridges, rivers, marshland and other landforms even though the clouds are optically opaque. The radiometric images of a few representative scenes along with photographs of the corresponding scenes are presented to demonstrate the resolution of the imager system.

  10. Radiometric and Spatial Characterization of High-Spatial Resolution Sensors

    NASA Technical Reports Server (NTRS)

    Thome, Kurtis; Zanoni, Vicki (Technical Monitor)

    2002-01-01

    The development and improvement of commercial hyperspatial sensors in recent years has increased the breadth of information that can be retrieved from spaceborne and airborne imagery. NASA, through it's Scientific Data Purchases, has successfully provided such data sets to its user community. A key element to the usefulness of these data are an understanding of the radiometric and spatial response quality of the imagery. This proposal seeks funding to examine the absolute radiometric calibration of the Ikonos sensor operated by Space Imaging and the recently-launched Quickbird sensor from DigitalGlobe. In addition, we propose to evaluate the spatial response of the two sensors. The proposed methods rely on well-understood, ground-based targets that have been used by the University of Arizona for more than a decade.

  11. Radiometric calibration procedures for a wideband infrared scene projector (WISP)

    NASA Astrophysics Data System (ADS)

    Flynn, David S.; Marlow, Steven A.; Bergin, Thomas P.; Kircher, James R.

    1999-07-01

    The Wideband Infrared Scene Projector (WISP) has been undergoing development for the Kinetic-Kill Vehicle Hardware-in-the-Loop Simulator facility at Eglin AFB, Florida. In order to perform realistic tests of an infrared seeker, the radiometric output of the WISP system must produce the same response in the seeker as the real scene. In order to ensure this radiometric realism, calibration procedures must be established and followed. This paper describes calibration procedures that have been used in recent tests. The procedures require knowledge of the camera spectral response in the seeker under test. The camera is set up to operate over the desired range of observable radiances. The camera is then nonuniformity corrected (NUCed) and calibrated with an extended blackbody. The camera drift rates are characterized, and as necessary, the camera is reNUCed and recalibrated. The camera is then set up to observe the WISP system, and calibration measurements are made of the camera/WISP system.

  12. Development and calibration of UV/VUV radiometric sources

    NASA Technical Reports Server (NTRS)

    Bridges, J. M.

    1993-01-01

    A program exists at NIST to calibrate radiometric sources for the spectral range from 118-350 nm. These include deuterium lamps, hollow-cathode lamps, RF-excited dimer lamps, and wall-stabilized argon arcs. Sources have been calibrated for and used by researchers in solar physics, astrophysics, atmospheric physics (ozone measurements), magnetically controlled fusion, and photobiology. The argon arcs were developed in our laboratory, and provide intense sources of both radiance and irradiance. Calibrations are performed relative to two primary sources, a wall-stabilized hydrogen arc and a 12,000 K black-body line arc, both developed in our laboratory. Also we recently have begun periodic calibrations on the NIST storage ring, SURF II, to insure consistency between our respective radiometric bases. Various sources have been calibrated for space' applications, including several which are flyable. Also, some development and testing of radiometers for semiconductor lithography were recently carried out with an intense argon arc source.

  13. Characterization of radiometric calibration of LANDSAT-4 TM reflective bands

    NASA Technical Reports Server (NTRS)

    Barker, J. L.; Abrams, R. B.; Ball, D. L.; Leung, K. C.

    1984-01-01

    Prelaunch and postlaunch internal calibrator, image, and background data is to characterize the radiometric performance of the LANDSAT-4 TM and to recommend improved procedures for radiometric calibration. All but two channels (band 2, channel 4; band 5, channel 3) behave normally. Gain changes relative to a postlaunch reference for channels within a band vary within 0.5 percent as a group. Instrument gain for channels in the cold focal plane oscillates. Noise in background and image data ranges from 0.5 to 1.7 counts. Average differences in forward and reverse image data indicate a need for separate calibration processing of forward and reverse scans. Precision is improved by increasing the pulse integration width from 31 to 41 minor frames, depending on the band.

  14. The OLI Radiometric Scale Realization Round Robin Measurement Campaign

    NASA Technical Reports Server (NTRS)

    Cutlip, Hansford; Cole,Jerold; Johnson, B. Carol; Maxwell, Stephen; Markham, Brian; Ong, Lawrence; Hom, Milton; Biggar, Stuart

    2011-01-01

    A round robin radiometric scale realization was performed at the Ball Aerospace Radiometric Calibration Laboratory in January/February 2011 in support of the Operational Land Imager (OLI) Program. Participants included Ball Aerospace, NIST, NASA Goddard Space Flight Center, and the University of Arizona. The eight day campaign included multiple observations of three integrating sphere sources by nine radiometers. The objective of the campaign was to validate the radiance calibration uncertainty ascribed to the integrating sphere used to calibrate the OLI instrument. The instrument level calibration source uncertainty was validated by quatnifying: (1) the long term stability of the NIST calibrated radiance artifact, (2) the responsivity scale of the Ball Aerospace transfer radiometer and (3) the operational characteristics of the large integrating sphere.

  15. Radiometric Compensation and Calibration for Radarsat ScanSAR

    NASA Technical Reports Server (NTRS)

    Jin, Michael Y.

    1993-01-01

    Due to lack of a standard for modeling the radar echo signal in terms of signal unit and coordinates as well as lack of a standard in designing the gain factors in each stage of a processor, absolute radiometric calibration of a SAR system is usually performed by treating the sensor and processor as one inseparable unit. This often makes the calibration procedure complicated and requiring the involvement of both radar system engineers and processor engineers in the whole process. This paper introduces a standard for modeling the radar echo signal and a standard in designing the gain factor of a ScanSAR processor. In this paper, the radar equation is derived based on the amount of energy instead of the power received from a backscatterer. These efforts lead to simple and easy-to-understand equations for radiometric compensation and calibration.

  16. Detection of coliform organisms in drinking water by radiometric method.

    PubMed

    Khurshid, S J; Bibi, S

    1991-07-01

    The radiometric method has been used for detection of coliform bacteria in water. The method is based on measuring the released metabolic 14CO2 from 14C-lactose in growth media containing coliform organisms incubated at 37 degrees C under continuous shaking. This rapid and sensitive radiometric method permits the detection of even single coliform organisms within 6 hours of incubation. Using this automated method, a total of 102 samples (in duplicate) collected from different areas in and around Rawalpindi and Islamabad were assessed for coliform bacteria. Of these 102 samples, 50 were tap water samples, 40 from wells and 6 each were from Rawal and Simly dams. About 47% and 67% tap water samples, while 62% and 74% well water samples were found unsatisfactory from around Islamabad and Rawalpindi areas, respectively. About 83% and 66% water samples from Rawal dam and Simly dam respectively were found to be unsatisfactory. PMID:1920760

  17. Metrological support for climatic time series of satellite radiometric data

    NASA Astrophysics Data System (ADS)

    Sapritsky, Victor I.; Burdakin, Andrey A.; Khlevnoy, Boris B.; Morozova, Svetlana P.; Ogarev, Sergey A.; Panfilov, Alexander S.; Krutikov, Vladimir N.; Bingham, Gail E.; Humpherys, Thomas; Tansock, Joseph J.; Thurgood, Alan V.; Privalsky, Victor E.

    2009-02-01

    A necessary condition for accumulating fundamental climate data records is the use of observation instruments whose stability and accuracy are sufficiently high for climate monitoring purposes; the number of instruments and their distribution in space should be sufficient for measurements with no spatial or temporal gaps. The continuous acquirement of data over time intervals of several decades can only be possible under the condition of simultaneous application of instruments produced by different manufacturers and installed on different platforms belonging to one or several countries. The design of standard sources for pre-flight calibrations and in-flight monitoring of instruments has to meet the most stringent requirements for the accuracy of absolute radiometric measurements and stability of all instruments. This means that the radiometric scales should be stable, accurate, and uniform. Current technologies cannot ensure the high requirements for stability and compatibility of radiometric scales: 0.1% per decade within the 0.3 - 3 μm band and 0.01 K per decade within the 3 - 25 μm band. It is suggested that these tasks can be aided through the use of the pure metals or eutectic alloy phase transition phenomenon that always occur under the same temperature. Such devices can be used for pre-flight calibrations and for on-board monitoring of the stability of radiometric instruments. Results of previous studies of blackbody models based upon the phase transition phenomenon are quite promising. A study of the phase transition of some materials in small cells was conducted for future application in onboard monitoring devices and its results are positive and allow us to begin preparations for similar experiments in space.

  18. LANDSAT-4 multispectral scanner (MSS) subsystem radiometric characterization

    NASA Technical Reports Server (NTRS)

    Alford, W. (Editor); Barker, J. (Editor); Clark, B. P.; Dasgupta, R.

    1983-01-01

    The multispectral band scanner (mass) and its spectral characteristics are described and methods are given for relating video digital levels on computer compatible tapes to radiance into the sensor. Topics covered include prelaunch calibration procedures and postlaunch radiometric processng. Examples of current data resident on the MSS image processing system are included. The MSS on LANDSAT 4 is compared with the scanners on earlier LANDSAT satellites.

  19. Changes in the Radiometric Sensitivity of SeaWiFS

    NASA Technical Reports Server (NTRS)

    McClain, Charles R.; Barnes, Robert A.; Eplee, Robert E., Jr.; Patt, Frederick S.

    1998-01-01

    We report on the lunar and solar measurements used to determine the changes in the radiometric sensitivity of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Radiometric sensitivity is defined as the output from the instrument (or from one of the instrument bands) per unit spectral radiance at the instrument's input aperture. Knowledge of the long-term repeatability of the SeaWiFS measurements is crucial to maintaining the quality of the ocean scenes derived from measurements by the instrument. For SeaWiFS bands 1 through 6 (412 nm through 670 rim), the change in radiometric sensitivity is less than 0.2% for the period from November 1997 through November 1998. For band 7 (765 nm), the change is about 1.5%, and for band 8 (865 nm) about 5%. The rates of change of bands 7 and 8, which were linear with time for the first eight months of lunar measurements, are now slowing. The scatter in the data points about the trend lines in this analysis is less than 0.3% for all eight SeaWiFS bands. These results are based on monthly measurements of the moon. Daily solar measurements using an onboard diffuser show that the radiometric sensitivities of the SeaWiFS bands have changed smoothly during the time intervals between lunar measurements. Since SeaWiFS measurements have continued past November 1998, the results presented here are considered as a snapshot of the instrument performance as of that date.

  20. Sentinel-2 radiometric image quality commissioning: first results

    NASA Astrophysics Data System (ADS)

    Lachérade, S.; Lonjou, V.; Farges, M.; Gamet, P.; Marcq, S.; Raynaud, J.-L.; Trémas, T.

    2015-10-01

    In partnership with the European Commission and in the frame of the Copernicus program, the European Space Agency (ESA) is developing the Sentinel-2 optical imaging mission devoted to the operational monitoring of land and coastal areas. The Sentinel-2 mission is based on a satellites constellation deployed in polar sun-synchronous orbit. Sentinel-2 offers a unique combination of global coverage with a wide field of view (290km), a high revisit (5 days with two satellites), a high spatial resolution (10m, 20m and 60m) and multi-spectral imagery (13 spectral bands in visible and shortwave infrared domains). The first satellite, Sentinel-2A, has been launched in June 2015. The Sentinel-2A Commissioning Phase starts immediately after the Launch and Early Orbit Phase and continues until the In-Orbit Commissioning Review which is planned three months after the launch. The Centre National d'Etudes Spatiales (CNES) supports ESA/ESTEC to insure the Calibration/Validation commissioning phase during the first three months in flight. This paper provides first an overview of the Sentinel-2 system and a description of the products delivered by the ground segment associated to the main radiometric specifications to achieve. Then the paper focuses on the preliminary radiometric results obtained during the in-flight commissioning phase. The radiometric methods and calibration sites used in the CNES image quality center to reach the specifications of the sensor are described. A status of the Sentinel-2A radiometric performances at the end of the first three months after the launch is presented. We will particularly address in this paper the results in term of absolute calibration, pixel to pixel relative sensitivity and MTF estimation.

  1. High speed radiometric measurements of IED detonation fireballs

    NASA Astrophysics Data System (ADS)

    Spidell, Matthew T.; Gordon, J. Motos; Pitz, Jeremey; Gross, Kevin C.; Perram, Glen P.

    2010-04-01

    Continuum emission is predominant in fireball spectral phenomena and in some demonstrated cases, fine detail in the temporal evolution of infrared spectral emissions can be used to estimate size and chemical composition of the device. Recent work indicates that a few narrow radiometric bands may reveal forensic information needed for the explosive discrimination and classification problem, representing an essential step in moving from "laboratory" measurements to a rugged, fieldable system. To explore phenomena not observable in previous experiments, a high speed (10μs resolution) radiometer with four channels spanning the infrared spectrum observed the detonation of nine home made explosive (HME) devices in the < 100lb class. Radiometric measurements indicate that the detonation fireball is well approximated as a single temperature blackbody at early time (0 < t <~ 3ms). The effective radius obtained from absolute intensity indicates fireball growth at supersonic velocity during this time. Peak fireball temperatures during this initial detonation range between 3000.3500K. The initial temperature decay with time (t <~ 10ms) can be described by a simple phenomenological model based on radiative cooling. After this rapid decay, temperature exhibits a small, steady increase with time (10 <~ t <~ 50ms) and peaking somewhere between 1000.1500K-likely the result of post-detonation combustion-before subsequent cooling back to ambient conditions . Radius derived from radiometric measurements can be described well (R2 > 0.98) using blast model functional forms, suggesting that energy release could be estimated from single-pixel radiometric detectors. Comparison of radiometer-derived fireball size with FLIR infrared imagery indicate the Planckian intensity size estimates are about a factor of two smaller than the physical extent of the fireball.

  2. BOREAS TE-18, 60-m, Radiometrically Rectified Landsat TM Imagery

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Knapp, David

    2000-01-01

    The BOREAS TE-18 team used a radiometric rectification process to produce standardized DN values for a series of Landsat TM images of the BOREAS SSA and NSA in order to compare images that were collected under different atmospheric conditions. The images for each study area were referenced to an image that had very clear atmospheric qualities. The reference image for the SSA was collected on 02-Sep-1994, while the reference image for the NSA was collected on 2 1 Jun-1995. The 23 rectified images cover the period of 07-Jul-1985 to 18-Sep-1994 in the SSA and 22-Jun-1984 to 09-Jun-1994 in the NSA. Each of the reference scenes had coincident atmospheric optical thickness measurements made by RSS-11. The radiometric rectification process is described in more detail by Hall et al. (1991). The original Landsat TM data were received from CCRS for use in the BOREAS project. Due to the nature of the radiometric rectification process and copyright issues, the full-resolution (30-m) images may not be publicly distributed. However, this spatially degraded 60-m resolution version of the images may be openly distributed and is available on the BOREAS CD-ROM series. After the radiometric rectification processing, the original data were degraded to a 60-m pixel size from the original 30-m pixel size by averaging the data over a 2- by 2-pixel window. The data are stored in binary image-format files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Activity Archive Center (DAAC).

  3. Airborne UV and visible spectrometer for DOAS and radiometric measurements

    NASA Astrophysics Data System (ADS)

    Petritoli, Andrea; Giovanelli, Giorgio; Bonafe, U.; Bortoli, Daniele; Kostadinov, Ivan; Ravegnani, Fabrizio

    1999-10-01

    A UV/Vis spectrometer (named GASCOD) for Differentiated Optical Absorption Spectroscopy (DOAS) has been developed at ISAO Institute and deployed for ground based measurements of stratospheric trace gases for several years at mid-latitudes and the Antarctic region. An airborne version, called GASCOD/A has been installed on board a M55-Geophysica airplane, a stratospheric research platform, capable of flying at an altitude of up to 20 Km. After a test campaign in Italy, the GASCOD/A performed successfully during the Airborne Polar Experiment in the winter 95/96. More recently, the instrument was upgraded to achieve higher sensitivity and reliability. Two additional radiometric channels were added. The input optics can turn in order to collect solar radiation from five different channels: one for detection of the zenith scattered radiation through the roof window (for DOAS measurement), two for direct and diffused radiation through two lateral windows and two for radiometric measurements through two 2(pi) optical heads mounted on the upper and bottom part of the aircraft and linked to the instrument by means of optical guides. The radiometric channels give us the possibility of calculating the photodissociation rate coefficients (J-values) of photochemical reactions involving ozone and nitrogen dioxides. The mechanical and optical layout of the instrument are presented and discussed, as well as laboratory tests and preliminary results obtained during flights onboard the M55- Geophysica.

  4. A Preliminary Analysis of LANDSAT-4 Thematic Mapper Radiometric Performance

    NASA Technical Reports Server (NTRS)

    Justice, C.; Fusco, L.; Mehl, W.

    1985-01-01

    The NASA raw (BT) product, the radiometrically corrected (AT) product, and the radiometrically and geometrically corrected (PT) product of a TM scene were analyzed examine the frequency distribution of the digital data; the statistical correlation between the bands; and the variability between the detectors within a band. The analyses were performed on a series of image subsets from the full scence. Results are presented from one 1024 c 1024 pixel subset of Realfoot Lake, Tennessee which displayed a representative range of ground conditions and cover types occurring within the full frame image. From this cursory examination of one of the first seven channel TM data sets, it would appear that the radiometric performance of the system is most satisfactory and largely meets pre-launch specifications. Problems were noted with Band 5 Detector 3 and Band 2 Detector 4. Differences were observed between forward and reverse scan detector responses both for the BT and AT products. No systematic variations were observed between odd and even detectors.

  5. Preliminary radiometric calibration assessment of ALOS AVNIR-2

    USGS Publications Warehouse

    Bouvet, M.; Goryl, P.; Chander, G.; Santer, R.; Saunier, S.

    2008-01-01

    This paper summarizes the activities carried out in the frame of the data quality activities of the Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) sensor onboard the Advanced Land Observing Satellite (ALOS). Assessment of the radiometric calibration of the AVNIR-2 multi-spectral imager is achieved via three intercomparisons to currently flying sensors over the Libyan desert, during the first year of operation. AU three methodologies indicate a slight underestimation of AVNIR-2 in band 1 by 4 to 7% with respect to other sensors radiometric scale. Band 2 does not show any obvious bias. Results for band 3 are affected by saturation due to inappropriate gain setting. Two methodologies indicate no significant bias in band 4. Preliminary results indicate possible degradations of the AVNIR-2 channels, which, when modeled as an exponentially decreasing functions, have time constants of respectively 13.2 %.year-1, 8.8%.year-1 and 0.1%.year-1 in band 1, 2 and 4 (with respect to the radiometric scale of the MEdium Resolution Imaging Spectrometer, MERIS). Longer time series of AVNIR-2 data are needed to draw final conclusions. ?? 2007 IEEE.

  6. Laboratory-Based BRDF Calibration of Radiometric Tarps

    NASA Technical Reports Server (NTRS)

    Georgiev, Georgi T.; Butler, James J.

    2007-01-01

    The current study provides the remote sensing community with important high accuracy laboratory-based BRDF calibration of radiometric tarps. The results illustrate the dependence of tarps' weft and warp threads orientation on BRDF. The study was done at incident angles of 0deg, 10deg, and 30deg; scatter zenith angles from 0deg to 60deg, and scatter azimuth angles of 0deg, 45deg, 90deg, 135deg, and 180deg. The wavelengths were 485nm, 550nm, 633nm and 800nm. The dependence is well defined at all measurement geometries and wavelengths. It can be as high as 8% at 0deg incident angle and 2% at 30deg incident angle. The fitted BRDF data show a very small discrepancy from the measured ones. New data on the forward and backscatter properties of radiometric tarps is reported. The backward scatter is well pronounced for the white samples. The black sample has well pronounced forward scatter. The BRDF characterization of radiometric tarps can be successfully extended to other structured surface fabric samples. The results are NIST traceable.

  7. Results of magnetic HGI and radiometric surveys in W. Canada

    SciTech Connect

    LeSchack, L.A.

    1997-05-19

    This article presents four case histories in which ground-based magnetic horizontal gradient intensity (HGI) and radiometric surveys were used in Western Canada for cost-effective geochemical exploration for hydrocarbons. The authors has developed these two surface exploration techniques from published studies and adapted them for use on the prairies the past 7 years. These surveys are used in conjunction with the usual geologic and seismic studies for: (1) evaluating prospects and land; (2) verifying seismic anomalies and inexpensively locating areas for conducting expensive 3D seismic surveys. Occasionally, as in two of the case histories discussed, these surveys were used successfully as stand-alone exploration methods where seismic exploration is not effective. The HGI and radiometric surveys measure, by geophysical methods, those effects associated with geochemical alterations due to vertical microseepage of hydrocarbons. The total cost, including permitting, data acquisition, data processing, and interpretation of the combination HGI and radiometric surveys is about 15% the total cost of a 3D seismic survey. Because of this, the author finds them an attractive and rapid survey adjunct to traditional exploration. They substantially reduce finding costs and significantly raise the probability of financial success.

  8. Radiometric packaging of uncooled microbolometer FPA arrays for space applications

    NASA Astrophysics Data System (ADS)

    García-Blanco, S.; Cote, P.; Leclerc, M.; Blanchard, N.; Desroches, Y.; Caron, J.-S.; Ngo Phong, L.; Chateauneuf, F.; Pope, T.

    2009-02-01

    INO has extensive experience in the design and fabrication of focal plane arrays (FPAs) of uncooled microbolometers. In particular, the FPA of 512×3 microbolometers, developed in collaboration with the Canadian Space Agency (CSA), has been selected for use in the NIRST (New Infrared Sensor Technology) radiometer of the SAC-D Aquarius mission. The FPA has been designed for pushbroom scanning of the Earth to provide radiometric data in the mid- and long-wave infrared for the monitoring of fires as well as thermal mapping of ocean temperature. Uncooled microbolometer detectors are suited for space applications due to their low power consumption while still exhibiting adequate performance. Furthermore, the spectral range of their response could be tuned from the mid- to the far-infrared to meet different mission requirements. In order to ensure that the detector receives only the thermal contribution from the desired target and to minimize radiometric error due to variation of the temperature of the surrounding during the measurements, a radiometric package is required. In a radiometric package the detector environment is thermally stabilized by means of a temperature controlled radiation shield. The radiation shield should also be designed to prevent stray radiation from reaching the detector. Under the Space Technology Development Program of the CSA, INO has designed, assembled and tested a radiometric package in order to characterize its performance and compatibility with the space environment. The operating spectral band is defined by the spectral characteristics of a bandpass filter placed in front of the FPA. For typical space missions, the package must pass standard environmental tests without degradation of its performance (thermal cycling from -55 to +85 °C according to MIL-STD-810, random acceleration up to 14 G RMS from 20-2000 Hz and shock up to 75 G). In order to ensure reliability in those conditions while maintaining optimum performance, an adequate

  9. Radiometric calibration of the Landsat MSS sensor series

    USGS Publications Warehouse

    Helder, Dennis L.; Karki, Sadhana; Bhatt, Rajendra; Micijevik, Esad; Aaron, David; Jasinski, Benjamin

    2012-01-01

    Multispectral remote sensing of the Earth using Landsat sensors was ushered on July 23, 1972, with the launch of Landsat-1. Following that success, four more Landsat satellites were launched, and each of these carried the Multispectral Scanner System (MSS). These five sensors provided the only consistent multispectral space-based imagery of the Earth's surface from 1972 to 1982. This work focuses on developing both a consistent and absolute radiometric calibration of this sensor system. Cross-calibration of the MSS was performed through the use of pseudoinvariant calibration sites (PICSs). Since these sites have been shown to be stable for long periods of time, changes in MSS observations of these sites were attributed to changes in the sensors themselves. In addition, simultaneous data collections were available for some MSS sensor pairs, and these were also used for cross-calibration. Results indicated substantial differences existed between instruments, up to 16%, and these were reduced to 5% or less across all MSS sensors and bands. Lastly, this paper takes the calibration through the final step and places the MSS sensors on an absolute radiometric scale. The methodology used to achieve this was based on simultaneous data collections by the Landsat-5 MSS and Thematic Mapper (TM) instruments. Through analysis of image data from a PICS location and through compensating for the spectral differences between the two instruments, the Landsat-5 MSS sensor was placed on an absolute radiometric scale based on the Landsat-5 TM sensor. Uncertainties associated with this calibration are considered to be less than 5%.

  10. Site characterization for calibration of radiometric sensors using vicarious method

    NASA Astrophysics Data System (ADS)

    Parihar, Shailesh; Rathore, L. S.; Mohapatra, M.; Sharma, A. K.; Mitra, A. K.; Bhatla, R.; Singh, R. S.; Desai, Yogdeep; Srivastava, Shailendra S.

    2016-05-01

    Radiometric performances of earth observation satellite/sensors vary from ground pre-launch calibration campaign to post launch period extended to lifetime of the satellite due to launching vibrations. Therefore calibration is carried out worldwide through various methods throughout satellite lifetime. In India Indian Space Research Organization (ISRO) calibrates the sensor of Resourcesat-2 satellite by vicarious method. One of these vicarious calibration methods is the reflectance-based approach that is applied in this study for radiometric calibration of sensors on-board Resouresat-2 satellite. The results of ground-based measurement of atmospheric conditions and surface reflectance are made at Bap, Rajasthan Calibration/Validation (Cal/Val) site. Cal/Val observations at site were carried out with hyper-spectral Spectroradiometer covering spectral range of 350nm- 2500nm for radiometric characterization of the site. The Sunphotometer/Ozonometer for measuring the atmospheric parameters has also been used. The calibrated radiance is converted to absolute at-sensor spectral reflectance and Top-Of-Atmosphere (TOA) radiance. TOA radiance was computed using radiative transfer model `Second simulation of the satellite signal in the solar spectrum' (6S), which can accurately simulate the problems introduced by the presence of the atmosphere along the path from Sun to target (surface) to Sensor. The methodology for band averaged reflectance retrieval and spectral reflectance fitting process are described. Then the spectral reflectance and atmospheric parameters are put into 6S code to predict TOA radiance which compare with Resourcesat-2 radiance. Spectral signature and its reflectance ratio indicate the uniformity of the site. Thus the study proves that the selected site is suitable for vicarious calibration of sensor of Resourcesat-2. Further the study demonstrates the procedure for similar exercise for site selection for Cal/Val analysis of other satellite over India

  11. BOREAS TE-18, 30-m, Radiometrically Rectified Landsat TM Imagery

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Knapp, David

    2000-01-01

    The BOREAS TE-18 team used a radiometric rectification process to produce standardized DN values for a series of Landsat TM images of the BOREAS SSA and NSA in order to compare images that were collected under different atmospheric conditions. The images for each study area were referenced to an image that had very clear atmospheric qualities. The reference image for the SSA was collected on 02-Sep-1994, while the reference image for the NSA was collected on 21-Jun-1995. the 23 rectified images cover the period of 07-Jul-1985 to 18 Sep-1994 in the SSA and from 22-Jun-1984 to 09-Jun-1994 in the NSA. Each of the reference scenes had coincident atmospheric optical thickness measurements made by RSS-11. The radiometric rectification process is described in more detail by Hall et al. (199 1). The original Landsat TM data were received from CCRS for use in the BOREAS project. The data are stored in binary image-format files. Due to the nature of the radiometric rectification process and copyright issues, these full-resolution images may not be publicly distributed. However, a spatially degraded 60-m resolution version of the images is available on the BOREAS CD-ROM series. See Sections 15 and 16 for information about how to possibly acquire the full resolution data. Information about the full-resolution images is provided in an inventory listing on the CD-ROMs. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Activity Archive Center (DAAC).

  12. Radiometric calibration of digital cameras using Gaussian processes

    NASA Astrophysics Data System (ADS)

    Schall, Martin; Grunwald, Michael; Umlauf, Georg; Franz, Matthias O.

    2015-05-01

    Digital cameras are subject to physical, electronic and optic effects that result in errors and noise in the image. These effects include for example a temperature dependent dark current, read noise, optical vignetting or different sensitivities of individual pixels. The task of a radiometric calibration is to reduce these errors in the image and thus improve the quality of the overall application. In this work we present an algorithm for radiometric calibration based on Gaussian processes. Gaussian processes are a regression method widely used in machine learning that is particularly useful in our context. Then Gaussian process regression is used to learn a temperature and exposure time dependent mapping from observed gray-scale values to true light intensities for each pixel. Regression models based on the characteristics of single pixels suffer from excessively high runtime and thus are unsuitable for many practical applications. In contrast, a single regression model for an entire image with high spatial resolution leads to a low quality radiometric calibration, which also limits its practical use. The proposed algorithm is predicated on a partitioning of the pixels such that each pixel partition can be represented by one single regression model without quality loss. Partitioning is done by extracting features from the characteristic of each pixel and using them for lexicographic sorting. Splitting the sorted data into partitions with equal size yields the final partitions, each of which is represented by the partition centers. An individual Gaussian process regression and model selection is done for each partition. Calibration is performed by interpolating the gray-scale value of each pixel with the regression model of the respective partition. The experimental comparison of the proposed approach to classical flat field calibration shows a consistently higher reconstruction quality for the same overall number of calibration frames.

  13. Cropland measurement using Thematic Mapper data and radiometric model

    NASA Technical Reports Server (NTRS)

    Lyon, John G.; Khuwaiter, I. H. S.

    1989-01-01

    To halt erosion and desertification, it is necessary to quantify resources that are affected. Necessary information includes inventory of croplands and desert areas as they change over time. Several studies indicate the value of remote sensor data as input to inventories. In this study, the radiometric modeling of spectral characteristics of soil and vegetation provides the theoretical basis for the remote sensing approach. Use of Landsat Thematic Mapper images allows measurement of croplands in Saudi Arabia, demonstrating the capability of the approach. The inventory techniques and remote sensing approach presented are potentially useful in developing countries.

  14. In-flight absolute radiometric calibration of the thematic mapper

    NASA Technical Reports Server (NTRS)

    Castle, K. R.; Holm, R. G.; Kastner, C. J.; Palmer, J. M.; Slater, P. N.; Dinguirard, M.; Ezra, C. E.; Jackson, R. D.; Savage, R. K.

    1983-01-01

    The TM multispectral scanner system was calibrated in an absolute manner before launch. To determine the temporal changes of the absolute radiometric calibration of the entire system, spectroradiometric measurements of the ground and the atmosphere were made simultaneously with TM collections over White Sands, New Mexico. By entering the measured values in an atmospheric radiative transfer program, the radiance levels of the in four of the spectral bands of the TM were determined. Tables show values for the reflectance of snow at White Sands measured by a modular 8 channel radiometer, and values for exoatmospheric irradiance within the TM passbands, calculated for the Earth-Sun distance using a solar radiometer.

  15. Radiometric calibration to consider in quantitative clinical fluorescence imaging measurements

    NASA Astrophysics Data System (ADS)

    Litorja, M.; Urbas, A.; Zong, Y.

    2015-03-01

    The fluorescent light detected by a clinical imager is assumed to be proportional only to the amount of fluorescent substance present in the sample and the level of excitation. Unfortunately, there are many factors that can add or subtract to the light signal directly attributable to the desired fluorescence emission, especially with fluorescence from inside the body imaged remotely. The quantification of fluorescence emission is feasible by calibrating the imager using international system of units (SI)-traceable physical and material calibration artifacts such that the detector's digital numbers (DN) can be converted to radiometric units. Here we discuss three calibration methods for quantitative clinical fluorescence imaging systems.

  16. Spectrally and Radiometrically Stable, Wideband, Onboard Calibration Source

    NASA Technical Reports Server (NTRS)

    Coles, James B.; Richardson, Brandon S.; Eastwood, Michael L.; Sarture, Charles M.; Quetin, Gregory R.; Porter, Michael D.; Green, Robert O.; Nolte, Scott H.; Hernandez, Marco A.; Knoll, Linley A.

    2013-01-01

    The Onboard Calibration (OBC) source incorporates a medical/scientific-grade halogen source with a precisely designed fiber coupling system, and a fiber-based intensity-monitoring feedback loop that results in radiometric and spectral stabilities to within less than 0.3 percent over a 15-hour period. The airborne imaging spectrometer systems developed at the Jet Propulsion Laboratory incorporate OBC sources to provide auxiliary in-use system calibration data. The use of the OBC source will provide a significant increase in the quantitative accuracy, reliability, and resulting utility of the spectral data collected from current and future imaging spectrometer instruments.

  17. A radiometric interpretive legend for Landsat digital thematic maps

    USGS Publications Warehouse

    Robinove, Charles J.

    1977-01-01

    A legend is suggested for use with computer-generated thematic maps made from Landsat digital data that designates some of the radiometric characteristics of each thematic map unit as well as the described terrain attributes of each map unit. The relationship between spectral band and radiance for each map unit is shown by a two-dimensional polygon with the four Landsat multispectral scanner bands plotted on the ordinate and radiance levels on the abscissa. The resulting shape is colored to correspond with the map unit color, thus facilitating the recognition and understanding of the computer-generated map units.

  18. Radiometric calibration of Landsat Thematic Mapper multispectral images

    USGS Publications Warehouse

    Chavez, P.S., Jr.

    1989-01-01

    A main problem encountered in radiometric calibration of satellite image data is correcting for atmospheric effects. Without this correction, an image digital number (DN) cannot be converted to a surface reflectance value. In this paper the accuracy of a calibration procedure, which includes a correction for atmospheric scattering, is tested. Two simple methods, a stand-alone and an in situ sky radiance measurement technique, were used to derive the HAZE DN values for each of the six reflectance Thematic Mapper (TM) bands. The DNs of two Landsat TM images of Phoenix, Arizona were converted to surface reflectances. -from Author

  19. Calibration method for radiometric and wavelength calibration of a spectrometer

    NASA Astrophysics Data System (ADS)

    Granger, Edward M.

    1998-12-01

    A new calibration target or Certified Reference Material (CRM) has been designed that uses violet, orange, green and cyan dyes ont cotton paper. This paper type was chosen because it has a relatively flat spectral response from 400 nm to 700 nm and good keeping properties. These specific dyes were chosen because the difference signal between the orange, cyan, green and purple dyes have certain characteristics that then a low the calibration of an instrument. The ratio between the difference readings is a direct function of the center wavelength of a given spectral band. Therefore, the radiometric and spectral calibration can be determined simultaneously from the physical properties of the reference materials.

  20. Earth Observing-1 Advanced Land Imager: Radiometric Response Calibration

    NASA Technical Reports Server (NTRS)

    Mendenhall, J. A.; Lencioni, D. E.; Evans, J. B.

    2000-01-01

    The Advanced Land Imager (ALI) is one of three instruments to be flown on the first Earth Observing mission (EO-1) under NASA's New Millennium Program (NMP). ALI contains a number of innovative features, including a wide field of view optical design, compact multispectral focal plane arrays, non-cryogenic HgCdTe detectors for the short wave infrared bands, and silicon carbide optics. This document outlines the techniques adopted during ground calibration of the radiometric response of the Advanced Land Imager. Results from system level measurements of the instrument response, signal-to-noise ratio, saturation radiance, and dynamic range for all detectors of every spectral band are also presented.

  1. A review of some radiometric calibration problems and methods

    NASA Technical Reports Server (NTRS)

    Slater, P. N.

    1984-01-01

    The in-flight radiometric calibration instrumentation and procedures of the Landsat Thematic Mapper and the high-resolution visible-range instruments of SPOT are illustrated with drawings and diagrams, characterized, and compared. Problems encountered in the laboratory calibration process, minimizing the temporal instability of the systems, identifying anomalies in the electronics in flight, and rechecking the calibration are examined, and it is pointed out that the stability of the calibration systems is less than that of the instruments themselves. The use of carefully measured ground-site data and atmospheric parameters in combination with radiative-transfer models for periodic calibration is recommended.

  2. Regression models for vegetation radar-backscattering and radiometric emission

    NASA Technical Reports Server (NTRS)

    Eom, H. J.

    1986-01-01

    Simple regression estimation of radar backscatter and radiometric emission from vegetative terrain is proposed, based on the exact radiative transfer models. A vegetative canopy is modeled as a Rayleigh scattering layer above an irregular Kirchhoff surface. The rms errors between the exact and the estimated ones are found to be less than 5 percent for emission, and 1 dB for the backscattering case, in most practical uses. The proposed formulas are useful in quickly estimating backscattering and emission from the vegetative terrain.

  3. Radiometric and Geometric Accuracy Analysis of Rasat Pan Imagery

    NASA Astrophysics Data System (ADS)

    Kocaman, S.; Yalcin, I.; Guler, M.

    2016-06-01

    RASAT is the second Turkish Earth Observation satellite which was launched in 2011. It operates with pushbroom principle and acquires panchromatic and MS images with 7.5 m and 15 m resolutions, respectively. The swath width of the sensor is 30 km. The main aim of this study is to analyse the radiometric and geometric quality of RASAT images. A systematic validation approach for the RASAT imagery and its products is being applied. RASAT image pair acquired over Kesan city in Edirne province of Turkey are used for the investigations. The raw RASAT data (L0) are processed by Turkish Space Agency (TUBITAK-UZAY) to produce higher level image products. The image products include radiometrically processed (L1), georeferenced (L2) and orthorectified (L3) data, as well as pansharpened images. The image quality assessments include visual inspections, noise, MTF and histogram analyses. The geometric accuracy assessment results are only preliminary and the assessment is performed using the raw images. The geometric accuracy potential is investigated using 3D ground control points extracted from road intersections, which were measured manually in stereo from aerial images with 20 cm resolution and accuracy. The initial results of the study, which were performed using one RASAT panchromatic image pair, are presented in this paper.

  4. Radiometric Characterization of Hyperspectral Imagers using Multispectral Sensors

    NASA Technical Reports Server (NTRS)

    McCorkel, Joel; Kurt, Thome; Leisso, Nathan; Anderson, Nikolaus; Czapla-Myers, Jeff

    2009-01-01

    The Remote Sensing Group (RSG) at the University of Arizona has a long history of using ground-based test sites for the calibration of airborne and satellite based sensors. Often, ground-truth measurements at these test sites are not always successful due to weather and funding availability. Therefore, RSG has also automated ground instrument approaches and cross-calibration methods to verify the radiometric calibration of a sensor. The goal in the cross-calibration method is to transfer the calibration of a well-known sensor to that of a different sensor, This work studies the feasibility of determining the radiometric calibration of a hyperspectral imager using multispectral a imagery. The work relies on the Moderate Resolution Imaging Spectroradiometer (M0DIS) as a reference for the hyperspectral sensor Hyperion. Test sites used for comparisons are Railroad Valley in Nevada and a portion of the Libyan Desert in North Africa. Hyperion bands are compared to MODIS by band averaging Hyperion's high spectral resolution data with the relative spectral response of M0DlS. The results compare cross-calibration scenarios that differ in image acquisition coincidence, test site used for the calibration, and reference sensor. Cross-calibration results are presented that show agreement between the use of coincident and non-coincident image pairs within 2% in most brands as well as similar agreement between results that employ the different MODIS sensors as a reference.

  5. A Preliminary Analysis of LANDSAT-4 Thematic Mapper Radiometric Performance

    NASA Technical Reports Server (NTRS)

    Justice, C.; Fusco, L.; Mehl, W.

    1984-01-01

    Analysis was performed to characterize the radiometry of three Thematic Mapper (TM) digital products of a scene of Arkansas. The three digital products examined were the NASA raw (BT) product, the radiometrically corrected (AT) product and the radiometrically and geometrically corrected (PT) product. The frequency distribution of the digital data; the statistical correlation between the bands; and the variability between the detectors within a band were examined on a series of image subsets from the full scene. The results are presented from one 1024 x 1024 pixel subset of Realfoot Lake, Tennessee which displayed a representative range of ground conditions and cover types occurring within the full frame image. Bands 1, 2 and 5 of the sample area are presented. The subsets were extracted from the three digital data products to cover the same geographic area. This analysis provides the first step towards a full appraisal of the TM radiometry being performed as part of the ESA/CEC contribution to the NASA/LIDQA program.

  6. Microwave radiometric signatures of temperature anomalies in tissue

    NASA Astrophysics Data System (ADS)

    Kelly, Patrick; Sobers, Tamara; St. Peter, Benjamin; Siqueira, Paul; Capraro, Geoffrey

    2012-03-01

    Because of its ability to measure the temperature-dependent power of electromagnetic radiation emitted from tissue down to several centimeters beneath the skin, microwave radiometry has long been of interest as a means for identifying the internal tissue temperature anomalies that arise from abnormalities in physiological parameters such as metabolic and blood perfusion rates. However, the inherent lack of specificity and resolution in microwave radiometer measurements has limited the clinical usefulness of the technique. The idea underlying this work is to make use of information (assumed to be available from some other modality) about the tissue configuration in the volume of interest to study and improve the accuracy of anomaly detection and estimation from radiometric data. In particular, knowledge of the specific anatomy and the properties of the overall measurement system enable determination of the signatures of localized physiological abnormalities in the radiometry data. These signatures are used to investigate the accuracy with which the location of an anomaly can be determined from radiometric measurements. Algorithms based on matches to entries in a signature dictionary are developed for anomaly detection and estimation. The accuracy of anomaly identification is improved when the coupling of power from the body to the sensor is optimized. We describe the design of a radiometer waveguide having dielectric properties appropriate for biomedical applications.

  7. a Comparison of LIDAR Reflectance and Radiometrically Calibrated Hyperspectral Imagery

    NASA Astrophysics Data System (ADS)

    Roncat, A.; Briese, C.; Pfeifer, N.

    2016-06-01

    In order to retrieve results comparable under different flight parameters and among different flight campaigns, passive remote sensing data such as hyperspectral imagery need to undergo a radiometric calibration. While this calibration, aiming at the derivation of physically meaningful surface attributes such as a reflectance value, is quite cumbersome for passively sensed data and relies on a number of external parameters, the situation is by far less complicated for active remote sensing techniques such as lidar. This fact motivates the investigation of the suitability of full-waveform lidar as a "single-wavelength reflectometer" to support radiometric calibration of hyperspectral imagery. In this paper, this suitability was investigated by means of an airborne hyperspectral imagery campaign and an airborne lidar campaign recorded over the same area. Criteria are given to assess diffuse reflectance behaviour; the distribution of reflectance derived by the two techniques were found comparable in four test areas where these criteria were met. This is a promising result especially in the context of current developments of multi-spectral lidar systems.

  8. Reduction of radiometric miscalibration--applications to pushbroom sensors.

    PubMed

    Rogass, Christian; Spengler, Daniel; Bochow, Mathias; Segl, Karl; Lausch, Angela; Doktor, Daniel; Roessner, Sigrid; Behling, Robert; Wetzel, Hans-Ulrich; Kaufmann, Hermann

    2011-01-01

    The analysis of hyperspectral images is an important task in Remote Sensing. Foregoing radiometric calibration results in the assignment of incident electromagnetic radiation to digital numbers and reduces the striping caused by slightly different responses of the pixel detectors. However, due to uncertainties in the calibration some striping remains. This publication presents a new reduction framework that efficiently reduces linear and nonlinear miscalibrations by an image-driven, radiometric recalibration and rescaling. The proposed framework-Reduction Of Miscalibration Effects (ROME)-considering spectral and spatial probability distributions, is constrained by specific minimisation and maximisation principles and incorporates image processing techniques such as Minkowski metrics and convolution. To objectively evaluate the performance of the new approach, the technique was applied to a variety of commonly used image examples and to one simulated and miscalibrated EnMAP (Environmental Mapping and Analysis Program) scene. Other examples consist of miscalibrated AISA/Eagle VNIR (Visible and Near Infrared) and Hawk SWIR (Short Wave Infrared) scenes of rural areas of the region Fichtwald in Germany and Hyperion scenes of the Jalal-Abad district in Southern Kyrgyzstan. Recovery rates of approximately 97% for linear and approximately 94% for nonlinear miscalibrated data were achieved, clearly demonstrating the benefits of the new approach and its potential for broad applicability to miscalibrated pushbroom sensor data. PMID:22163960

  9. In-flight radiometric calibration of AVIRIS in 1994

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Conel, James E.; Helmlinger, Mark; Vandenbosch, Jeannette; Hajek, Pavel

    1995-01-01

    The AVIRIS sensor must be calibrated at the time it measures spectra from the ER-2 airborne platform in order to achieve research and application objectives that are both quantitative and physically based. However, the operational environment inside the Q-bay of the ER-2 at 20 km altitude differs from that in the AVIRIS laboratory with respect to temperature, pressure, vibration, and high-frequency electromagnetic fields. Experiments at surface calibration targets are used in each flight season to confirm the accuracy of AVIRIS in-flight radiometric calibrations. For these experiments, the MODTRAN radiative transfer code is constrained by using in situ measurements to independently predict the upwelling spectral radiance arriving at AVIRIS for a specific calibration target. AVIRIS calibration is validated in flight by comparing the MODTRAN-predicted radiance to the laboratory-calibrated radiance measured by the AVIRIS sensor for the same time over the calibration target. We present radiometric calibration results for the AVIRIS in-flight calibration experiment held at the beginning of the 1994 flight season.

  10. Principal Component Noise Filtering for NAST-I Radiometric Calibration

    NASA Technical Reports Server (NTRS)

    Tian, Jialin; Smith, William L., Sr.

    2011-01-01

    The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed- Interferometer (NAST-I) instrument is a high-resolution scanning interferometer that measures emitted thermal radiation between 3.3 and 18 microns. The NAST-I radiometric calibration is achieved using internal blackbody calibration references at ambient and hot temperatures. In this paper, we introduce a refined calibration technique that utilizes a principal component (PC) noise filter to compensate for instrument distortions and artifacts, therefore, further improve the absolute radiometric calibration accuracy. To test the procedure and estimate the PC filter noise performance, we form dependent and independent test samples using odd and even sets of blackbody spectra. To determine the optimal number of eigenvectors, the PC filter algorithm is applied to both dependent and independent blackbody spectra with a varying number of eigenvectors. The optimal number of PCs is selected so that the total root-mean-square (RMS) error is minimized. To estimate the filter noise performance, we examine four different scenarios: apply PC filtering to both dependent and independent datasets, apply PC filtering to dependent calibration data only, apply PC filtering to independent data only, and no PC filters. The independent blackbody radiances are predicted for each case and comparisons are made. The results show significant reduction in noise in the final calibrated radiances with the implementation of the PC filtering algorithm.

  11. Reduction of Radiometric Miscalibration—Applications to Pushbroom Sensors

    PubMed Central

    Rogaß, Christian; Spengler, Daniel; Bochow, Mathias; Segl, Karl; Lausch, Angela; Doktor, Daniel; Roessner, Sigrid; Behling, Robert; Wetzel, Hans-Ulrich; Kaufmann, Hermann

    2011-01-01

    The analysis of hyperspectral images is an important task in Remote Sensing. Foregoing radiometric calibration results in the assignment of incident electromagnetic radiation to digital numbers and reduces the striping caused by slightly different responses of the pixel detectors. However, due to uncertainties in the calibration some striping remains. This publication presents a new reduction framework that efficiently reduces linear and nonlinear miscalibrations by an image-driven, radiometric recalibration and rescaling. The proposed framework—Reduction Of Miscalibration Effects (ROME)—considering spectral and spatial probability distributions, is constrained by specific minimisation and maximisation principles and incorporates image processing techniques such as Minkowski metrics and convolution. To objectively evaluate the performance of the new approach, the technique was applied to a variety of commonly used image examples and to one simulated and miscalibrated EnMAP (Environmental Mapping and Analysis Program) scene. Other examples consist of miscalibrated AISA/Eagle VNIR (Visible and Near Infrared) and Hawk SWIR (Short Wave Infrared) scenes of rural areas of the region Fichtwald in Germany and Hyperion scenes of the Jalal-Abad district in Southern Kyrgyzstan. Recovery rates of approximately 97% for linear and approximately 94% for nonlinear miscalibrated data were achieved, clearly demonstrating the benefits of the new approach and its potential for broad applicability to miscalibrated pushbroom sensor data. PMID:22163960

  12. Radiometric calibration of Landsat Thematic Mapper Thermal Band

    NASA Technical Reports Server (NTRS)

    Wukelic, G. E.; Gibbons, D. E.; Martucci, L. M.; Foote, H. P.

    1989-01-01

    Radiometric calibration of satellite-acquired data is essential for quantitative scientific studies, as well as for a variety of image-processing applications. This paper describes a multiyear, on-orbit radiometric calibration of the Landsat Thematic Mapper (TM) Band 6 conducted at DOE's Pacific Northwest Laboratory. Numerous Landsat TM scenes acquired and analyzed included day and night coverages at several geographical locations over several seasons. Concurrent with Landsat overpasses, thermal field and local meteorological (surface and radiosonde) measurements were collected. At-satellite (uncorrected) radiances and temperatures for water and nonwater land cover were compared to ground truth (GT) measurements after making adjustments for atmospheric (using LOWTRAN), mixed-pixel, and emissivity effects. Results indicate that, for both water and nonwater features, TM Band 6 average corrected temperature determinations using local radiosonde data to adjust for atmospheric effects, and using appropriate emissivities, are within 1.0 C of GT temperature values. Temperatures of water pixels derived from uncorrected TM Band 6 data varied roughly between 1 and 3 C of ground truth values for water temperatures ranging between 4 and 24 C. Moreover, corrections using nonlocal and noncoincident radiosonde data resulted in errors as large as 12 C. Corrections using the U.S. Standard Atmosphere gave temperature values within 1 to 2 C of GT. The average uncertainty for field instruments was + or - 0.2 C; average uncertainty for Landsat TM corrected temperature determinations was + or - 0.4 C.

  13. Investigation of radiometric properties of the LANDSAT-4 multispectral scanner

    NASA Technical Reports Server (NTRS)

    Malila, W. A. (Principal Investigator); Rice, D. P.

    1983-01-01

    The radiometric data quality of the LANDSAT 4 multispectral scanner (MSS) was examined using several LANDSAT 4 frames. It was found that LANDSAT 4 MSS produces high-quality data of the caliber experienced with previous LANDSATS. For example, the detector equalization procedure worked well, leaving a residual banding effect of about 0.3 digital counts RMS, close to the theoretical minimum value of quantization error. Nevertheless, artifacts of the data were found, two of which were not experienced in previous MSS data. A low-level coherent noise effect was observed in all bands, with a magnitude of about 0.5 digital counts and a frequency of approximately 28 KHz (representing a wavelength of about 3.6 pixels); a substantial increase in processing complexity would be required to reduce this artifact in the data. Also, a substantial scan-length variation (of up to six pixels) was noted in MSS data when the TM sensor was operating; the LANDSAT 4 correction algorithms being applied routinely by the EROS Data Center to produce a p-type data should remove most of this variation. Between-satellite calibrations were examined in paired LANDSAT 3 and LANDSAT 4 MSS data sets, which were closely matched in acquisition time and place. Radiometric comparisons showed that all bands were highly linear in digital counts, and a well-determined linear transformation between the MSS's was established.

  14. On the observability of Mars entry navigation using radiometric measurements

    NASA Astrophysics Data System (ADS)

    Yu, Zhengshi; Cui, Pingyuan; Zhu, Shengying

    2014-10-01

    A thorough observability analysis of the Mars entry navigation using radiometric measurements from ground based beacons is performed. This analysis involves the evaluation of the Fisher information matrix which is derived from the maximum likelihood estimation. A series of navigation cases with multiple beacons are investigated, and both range and range-rate measurements are considered. The determinant of Fisher information matrix is used to quantify the observability of navigation system, while the trace of Fisher information matrix is used to determine the lower-bound of estimation errors. For one and two beacon cases, the navigation system is unobservable. However, the eigenvectors of Fisher information matrix give the observable and unobservable component. When three or more beacon measurements are employed, the states of entry vehicle become observable. Some valuable analytic conclusions on the relationship between the geometric configuration of beacons and observability are obtained consequently. Finally, simulation results from two navigation examples indicate that our effort is useful for understanding and assessing the observability of the Mars entry navigation using radiometric measurements.

  15. Radiometric versus geometric, linear, and nonlinear vignetting coefficient.

    PubMed

    Duma, Virgil-Florin

    2009-11-10

    We analyze the vignetting phenomenon both for optical systems with objects placed at finite distances and for systems with objects at infinity. Four of the possible definitions of the vignetting coefficient k, only two of them existing in the literature, are discussed. We propose two new definitions, i.e., a nonlinear geometric coefficient that is, in part, an analytical model of the vignetting characterization using optical software and a radiometric vignetting coefficient. The object space of each type of optical systems is studied first, defining its characteristic light circles and cones. Several simplifying assumptions are made for each of the two cases considered to derive analytical equations of the vignetting coefficient and thus to determine the best definition to be used. A geometric vignetting coefficient with two expressions, a linear classical and easy-to-use one and a nonlinear, that we propose for both types of systems is obtained. This nonlinear geometric vignetting coefficient proves to be more adequate in modeling the phenomenon, but it does not entirely fit the physical reality. We finally demonstrate that the radiometric vignetting coefficient we define and derive as a view factor for both types of optical systems is the most appropriate one. The half vignetting level, necessary in most optical design procedures to obtain a satisfactory illumination level in the image plane, is also discussed. PMID:19904336

  16. Radiometric characterization of hyperspectral imagers using multispectral sensors

    NASA Astrophysics Data System (ADS)

    McCorkel, Joel; Thome, Kurt; Leisso, Nathan; Anderson, Nikolaus; Czapla-Myers, Jeff

    2009-08-01

    The Remote Sensing Group (RSG) at the University of Arizona has a long history of using ground-based test sites for the calibration of airborne and satellite based sensors. Often, ground-truth measurements at these tests sites are not always successful due to weather and funding availability. Therefore, RSG has also employed automated ground instrument approaches and cross-calibration methods to verify the radiometric calibration of a sensor. The goal in the cross-calibration method is to transfer the calibration of a well-known sensor to that of a different sensor. This work studies the feasibility of determining the radiometric calibration of a hyperspectral imager using multispectral imagery. The work relies on the Moderate Resolution Imaging Spectroradiometer (MODIS) as a reference for the hyperspectral sensor Hyperion. Test sites used for comparisons are Railroad Valley in Nevada and a portion of the Libyan Desert in North Africa. Hyperion bands are compared to MODIS by band averaging Hyperion's high spectral resolution data with the relative spectral response of MODIS. The results compare cross-calibration scenarios that differ in image acquisition coincidence, test site used for the calibration, and reference sensor. Cross-calibration results are presented that show agreement between the use of coincident and non-coincident image pairs within 2% in most bands as well as similar agreement between results that employ the different MODIS sensors as a reference.

  17. Radiometric infrared focal plane array imaging system for thermographic applications

    NASA Technical Reports Server (NTRS)

    Esposito, B. J.; Mccafferty, N.; Brown, R.; Tower, J. R.; Kosonocky, W. F.

    1992-01-01

    This document describes research performed under the Radiometric Infrared Focal Plane Array Imaging System for Thermographic Applications contract. This research investigated the feasibility of using platinum silicide (PtSi) Schottky-barrier infrared focal plane arrays (IR FPAs) for NASA Langley's specific radiometric thermal imaging requirements. The initial goal of this design was to develop a high spatial resolution radiometer with an NETD of 1 percent of the temperature reading over the range of 0 to 250 C. The proposed camera design developed during this study and described in this report provides: (1) high spatial resolution (full-TV resolution); (2) high thermal dynamic range (0 to 250 C); (3) the ability to image rapid, large thermal transients utilizing electronic exposure control (commandable dynamic range of 2,500,000:1 with exposure control latency of 33 ms); (4) high uniformity (0.5 percent nonuniformity after correction); and (5) high thermal resolution (0.1 C at 25 C background and 0.5 C at 250 C background).

  18. Radiometric tests on wet and dry antenna reflector surface panels

    NASA Technical Reports Server (NTRS)

    Otoshi, T. Y.; Franco, M. M.

    1990-01-01

    The results of X-band noise temperature tests on two types of antenna surface panels are presented. The first type tested was a solid antenna panel, while the second type was a perforated panel with 3/16-in.-diameter holes. Measurements were made at 8.45 GHz using an X-band radiometric system. Included in this article are measured noise temperature contributions from: (1) thermal diffusive white paint on solid and perforated panels, and (2) water sprayed on both painted and unpainted perforated panels. Experiments on perforated panels were restricted to the 3/16-in.-diameter hole panels formerly used on Deep Space Network 64-m antennas. Rigorous calibration equations, applicable to a variety of antenna panel and dichroic plate test configurations, are presented. It was demonstrated that an accurate, stable radiometric measurement system of the type used for the results of this research makes it possible to obtain information that would be much more difficult to obtain using other techniques.

  19. Calculated sensitivities of several optical radiometric indices for vegetation canopies

    NASA Technical Reports Server (NTRS)

    Shultis, J. K.

    1991-01-01

    The present study employs a radiative transfer model for a vegetation canopy to compute several quantities used in remote sensing applications and to determine the sensitivity of these radiometric quantities to several of the important problem parameters. Attention is given to the ratio of near IR to visible reflected intensities in the nadir direction, the ratio of the fraction of incident energy reflected in the near IR to that in the visible, the normalized difference between the near IR and visible nadir-reflected intensities, and the visible intensity transmitted in a given downward direction. A realistic radiative transfer model is proposed for calculating these radiometric quantities. With these models, the sensitivity of the reflected and transmitted quantities to various canopy and illumination conditions are then determined. The sensitivity of the calculated quantities are presented as a function of the leaf area index of the canopy, and, for the reflected quantities, also as a function of the fraction of visible light absorbed in the canopy.

  20. Radiometric measurement of differential metabolism of fatty acid by mycobacteria

    SciTech Connect

    Camargo, E.E.; Kertcher, J.A.; Larson, S.M.; Tepper, B.S.; Wagner, H.N. Jr.

    1982-06-01

    An assay system has been developed based on automated radiometric quantification of /sup 14/CO2 produced through oxidation of (1-/sup 14/C) fatty acids by mycobacteria. Two stains of M. tuberculosis (H37Rv and Erdman) and one of M. bovis (BCG) in 7H9 medium (ADC) with 1.0 microCi of one of the fatty acids (butyric, hexanoic, octanoic, decanoic, lauric, myristic, palmitic, stearic, oleic, linoleic and linolenic) were studied. Results previously published on M. lepraemurium (Hawaiian) were also included for comparison. Both strains of M. tuberculosis had maximum /sup 14/CO2 production from hexanoic acid. Oxidation of butyric and avid oxidation of lauric acids were also found with the H37Rv strain but not with Erdman. In contrast, /sup 14/CO2 production by M. bovis was greatest from lauric and somewhat less from decanoic acid. M. lepraemurium showed increasing oxidation rates from myristic, decanoic and lauric acids. Assimilation studies of M. tuberculosis H37Rv confirmed that most of the oxidized substrates were converted into by-products with no change in those from which no oxidation was found. These data suggest that the radiometric measurement of differential fatty acid metabolism may provide a basis of strain identification of the genus Mycobacterium.

  1. Branching Ratios for The Radiometric Calibration of EUNIS-2012

    NASA Technical Reports Server (NTRS)

    Daw, Adrian N.; Bhatia, A. K.; Rabin, Douglas M.

    2012-01-01

    The Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) sounding rocket instrument is a two-channel imaging spectrograph that observes the solar corona and transition region with high spectral resolution and a rapid cadence made possible by unprecedented sensitivity. The upcoming flight will incorporate a new wavelength channel covering the range 524-630 Angstroms, the previously-flown 300-370 Angstroms channel, and the first flight demonstration of cooled active pixel sensor (APS) arrays. The new 524-630 Angstrom channel incorporates a Toroidal Varied Line Space (TVLS) grating coated with B4C/Ir, providing broad spectral coverage and a wide temperature range of 0.025 to 10 MK. Absolute radiometric calibration of the two channels is being performed using a hollow cathode discharge lamp and NIST-calibrated AXUV-100G photodiode. Laboratory observations of He I 584 Angstroms and He II 304 Angstroms provide absolute radiometric calibrations of the two channels at those two respective wavelengths by using the AXUV photodiode as a transfer standard. The spectral responsivity is being determined by observing line pairs with a common upper state in the spectra of Ne I-III and Ar II-III. Calculations of A-values for the observed branching ratios are in progress.

  2. Evaluating Radiometric Measurements Using a Fixed 45 Degrees Responsivity and Zenith Angle Dependent Responsivities (Poster)

    SciTech Connect

    Dooraghi, M.; Habte, A.; Reda, I.; Sengupta, M.; Gotseff, P.; Andreas, A.; Anderberg, M.

    2014-03-01

    This poster seeks to demonstrate the importance and application of an existing but unused approach that ultimately reduces the uncertainty of radiometric measurements. Current radiometric data is based on a single responsivity value that introduces significant uncertainty to the data, however, through using responsivity as a function of solar zenith angle, the uncertainty could be decreased by 50%.

  3. Galileo SSI/Gaspra Radiometrically Calibrated Images V1.0

    NASA Astrophysics Data System (ADS)

    Domingue, D. L.

    2015-05-01

    This data set includes Galileo Orbiter SSI radiometrically calibrated images of the asteroid 951 Gaspra, created using ISIS software and assuming nadir pointing. This is an original delivery of radiometrically calibrated files, not an update to existing files. All images archived include the the asteroid within the image frame. Calibration was performed in 2013-2014.

  4. Application of radiometric surface temperature for surface energy balance estimation: John Monteith's contributions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over 25 years ago, Huband and Monteith paper’s investigating the radiative surface temperature and the surface energy balance of a wheat canopy, highlighted the key issues in computing fluxes with radiometric surface temperature. These included the relationship between radiometric and aerodynamic s...

  5. The Landsat Data Continuity Mission Operational Land Imager (OLI) Radiometric Calibration

    NASA Technical Reports Server (NTRS)

    Markham, Brian L.; Dabney, Philip W.; Murphy-Morris, Jeanine E.; Knight, Edward J.; Kvaran, Geir; Barsi, Julia A.

    2010-01-01

    The Operational Land Imager (OLI) on the Landsat Data Continuity Mission (LDCM) has a comprehensive radiometric characterization and calibration program beginning with the instrument design, and extending through integration and test, on-orbit operations and science data processing. Key instrument design features for radiometric calibration include dual solar diffusers and multi-lamped on-board calibrators. The radiometric calibration transfer procedure from NIST standards has multiple checks on the radiometric scale throughout the process and uses a heliostat as part of the transfer to orbit of the radiometric calibration. On-orbit lunar imaging will be used to track the instruments stability and side slither maneuvers will be used in addition to the solar diffuser to flat field across the thousands of detectors per band. A Calibration Validation Team is continuously involved in the process from design to operations. This team uses an Image Assessment System (IAS), part of the ground system to characterize and calibrate the on-orbit data.

  6. An overview of in-orbit radiometric calibration of typical satellite sensors

    NASA Astrophysics Data System (ADS)

    Zhou, G. Q.; Li, C. Y.; Yue, T.; Jiang, L. J.; Liu, N.; Sun, Y.; Li, M. Y.

    2015-06-01

    This paper reviews the development of in-orbit radiometric calibration methods in the past 40 years. It summarizes the development of in-orbit radiometric calibration technology of typical satellite sensors in the visible/near-infrared bands and the thermal infrared band. Focuses on the visible/near-infrared bands radiometric calibration method including: Lamp calibration and solar radiationbased calibration. Summarizes the calibration technology of Landsat series satellite sensors including MSS, TM, ETM+, OLI, TIRS; SPOT series satellite sensors including HRV, HRS. In addition to the above sensors, there are also summarizing ALI which was equipped on EO-1, IRMSS which was equipped on CBERS series satellite. Comparing the in-orbit radiometric calibration technology of different periods but the same type satellite sensors analyzes the similarities and differences of calibration technology. Meanwhile summarizes the in-orbit radiometric calibration technology in the same periods but different country satellite sensors advantages and disadvantages of calibration technology.

  7. Radiometric resolution for monitoring vegetation: How many bits are needed?

    NASA Technical Reports Server (NTRS)

    Tucker, C. J.

    1979-01-01

    The significance of the various number of radiometric quantizing levels required for satellite monitoring of vegetation resources was evaluated by using in situ collected spectral reflectance data, an atmospheric radiative transfer simulation model, and a satellite sensor simulation model. Reflectance data were converted to radiance data; passed through a model atmosphere to an altitude of 706 km; and subsequently quantized at 16, 32, 64, 128, 256, and 512 digital count levels for Thematic Mapper bands TM3(0.63 - 0.69 microns) and TM4(0.76 - 0.90 microns). The simulated digital count data were regressed against the in situ biological data to quantify the relationship between quantizing levels.

  8. Laboratory Measurement of Bidirectional Reflectance of Radiometric Tarps

    NASA Technical Reports Server (NTRS)

    Knowlton, Kelly

    2004-01-01

    This experiment measured the reflectance of tarps with ground instruments in order to check radiometric calibration, validate atmospheric correction, and predict at-sensor radiance for satellite instruments. The procedure of this experiment is as follows: 1) Assemble laboratory apparatus to duplicate ground reference measurement geometry and satellite measurement geometry; 2) Measure spectral radiance with Optronics OL 750 double monochromator/spectroradiometer; 3) Measure radiance of NIST-calibrated Spectralon panel irradiated by collimated light at incidence angle of calibrated reflectance (20 deg, 30 deg, 40 deg, or 50 deg), viewing normal to panel surface; 4) Measure radiance of Spectralon panel irradiated at incidence angle equal to solar zenith angle at time of overpass; 5) Calculate reflectance of Spectralon panel irradiated at solar zenith angle, viewing normal to panel surface (ground geometry).

  9. Active radiometric calorimeter for absolute calibration of radioactive sources

    NASA Astrophysics Data System (ADS)

    Stump, K. E.; DeWerd, L. A.; Rudman, D. A.; Schima, S. A.

    2005-03-01

    This report describes the design and initial noise floor measurements of a radiometric calorimeter designed to measure therapeutic medical radioactive sources. The instrument demonstrates a noise floor of approximately 2 nW. This low noise floor is achieved by using high temperature superconducting (HTS) transition edge sensor (TES) thermometers in a temperature-control feedback loop. This feedback loop will be used to provide absolute source calibrations based upon the electrical substitution method. Other unique features of the calorimeter are (a) its ability to change sources for calibration without disrupting the vacuum of the instrument, and (b) the ability to measure the emitted power of a source in addition to the total contained source power.

  10. Development of a portable ambient temperature radiometric assaying instrument

    SciTech Connect

    Lavietes, A.D.; McQuaid, J.H.; Ruhter, W.D.

    1994-10-01

    There is a strong need for portable radiometric instrumentation that can accurately confirm the presence of nuclear materials and allow isotopic analysis of radionuclides in the field. To fulfill this need we are developing a hand-held, non-cryogenic, low-power gamma- and x-ray measurement and analysis instrument that can both search and then accurately verify the presence of nuclear materials. We report on the use of cadmium zinc telluride detectors, signal processing electronics, and the new field-portable instrument based on the MicroNOMAD Multichannel Analyzer from EG&G ORTBC. We also describe the isotopic analysis that allows uranium enrichment measurements to be made accurately in the field.

  11. Advanced radiometric millimeter-wave scene simulation: ARMSS

    NASA Astrophysics Data System (ADS)

    Hauss, Bruce I.; Agravante, Hiroshi H.; Chaiken, Steven

    1997-06-01

    In order to predict the performance of a passive millimeter wave sensor under a variety of weather, terrain and sensor operational conditions, TRW has developed the Advanced Radiometric Millimeter-Wave Scene Simulation (ARMSS) code. This code provides a comprehensive, end-to-end scene simulation capability based on rigorous, `first-principle' physics models of the passive millimeter wave phenomenology and sensor characteristics. The ARMSS code has been extensively benchmarked against both data in the literature and a wide array of millimeter-wave-field-imaging data. The code has been used in support of numerous passive millimeter wave technology programs for interpreting millimeter wave data, establishing scene signatures, performing mission analyses, and developing system requirements for the design of millimeter wave sensor systems. In this paper, we will present details of the ARMSS code and describe its current use in defining system requirements for the passive millimeter wave camera being developed under the Passive Millimeter Wave Camera Consortium led by TRW.

  12. New Sentinel-2 radiometric validation approaches (SEOM program)

    NASA Astrophysics Data System (ADS)

    Bruniquel, Véronique; Lamquin, Nicolas; Ferron, Stéphane; Govaerts, Yves; Woolliams, Emma; Dilo, Arta; Gascon, Ferran

    2016-04-01

    SEOM is an ESA program element whose one of the objectives aims at launching state-of-the-art studies for the scientific exploitation of operational missions. In the frame of this program, ESA awarded ACRI-ST and its partners Rayference and National Physical Laboratory (NPL) early 2016 for a R&D study on the development and intercomparison of algorithms for validating the Sentinel-2 radiometric L1 data products beyond the baseline algorithms used operationally in the frame of the S2 Mission Performance Centre. In this context, several algorithms have been proposed and are currently in development: The first one is based on the exploitation of Deep Convective Cloud (DCC) observations over ocean. This method allows an inter-band radiometry validation from the blue to the NIR (typically from B1 to B8a) from a reference band already validated for example with the well-known Rayleigh method. Due to their physical properties, DCCs appear from the remote sensing point of view to have bright and cold tops and they can be used as invariant targets to monitor the radiometric response degradation of reflective solar bands. The DCC approach is statistical i.e. the method shall be applied on a large number of measurements to derive reliable statistics and decrease the impact of the perturbing contributors. The second radiometric validation method is based on the exploitation of matchups combining both concomitant in-situ measurements and Sentinel-2 observations. The in-situ measurements which are used here correspond to measurements acquired in the frame of the RadCalNet networks. The validation is performed for the Sentinel-2 bands similar to the bands of the instruments equipping the validation site. The measurements from the Cimel CE 318 12-filters BRDF Sun Photometer installed recently in the Gobabeb site near the Namib desert are used for this method. A comprehensive verification of the calibration requires an analysis of MSI radiances over the full dynamic range

  13. Airborne Millimeter-Wave Radiometric Observations of Cirrus Clouds

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Racette, P.

    1997-01-01

    This paper reports the first radiometric measurements of cirrus clouds in the frequency range of 89-325 GHz from a high-altitude aircraft flight. The measurements are conducted with a Millimeter-wave Imaging Radiometer (MIR) on board the NASA ER-2 aircraft over a region in northern Oklahoma. Aboard the same aircraft are a cloud lidar system and a multichannel radiometer operating at the visible and infrared wavelengths. The instrument ensemble is well suited for identifying cirrus clouds. It is shown that the depressions in brightness temperatures associated with a few intense cirrus clouds occur at all frequency channels of the MIR. Estimates of total ice water path of the cirrus clouds are derived from comparisons of radiative transfer calculations and observed brightness depressions.

  14. ASTER VNIR and SWIR Radiometric Calibration and Atmospheric Correction

    NASA Astrophysics Data System (ADS)

    Arai, Kohei; Thome, Kurtis; Iwasaki, Akira; Biggar, Stuart

    As described in the previous chapter, ASTER relies on three separate subsystems to cover the full spectral range from the visible and near infrared (VNIR), short-wave infrared (SWIR), to the thermal infrared (TIR). Establishing the accuracy of data from all three subsystems requires both sensor-related calibration and atmospheric correction. The dominance of reflected solar energy in the VNIR and SWIR, and emitted terrestrial radiation in the TIR allows separate treatment of the two spectral regions. TIR calibration and correction are covered in a separate chapter. This chapter has two main goals: (1) to allow the user to understand ASTER's radiometric calibration and atmospheric correction processes that enable conversion of VNIR and SWIR digital numbers (DN) to at-sensor reflectance and spectral radiance, and (2) to provide a succinct analysis of the SWIR crosstalk problem and its solutions.

  15. Determination of precipitation profiles from airborne passive microwave radiometric measurements

    NASA Technical Reports Server (NTRS)

    Kummerow, Christian; Hakkarinen, Ida M.; Pierce, Harold F.; Weinman, James A.

    1991-01-01

    This study presents the first quantitative retrievals of vertical profiles of precipitation derived from multispectral passive microwave radiometry. Measurements of microwave brightness temperature (Tb) obtained by a NASA high-altitude research aircraft are related to profiles of rainfall rate through a multichannel piecewise-linear statistical regression procedure. Statistics for Tb are obtained from a set of cloud radiative models representing a wide variety of convective, stratiform, and anvil structures. The retrieval scheme itself determines which cloud model best fits the observed meteorological conditions. Retrieved rainfall rate profiles are converted to equivalent radar reflectivity for comparison with observed reflectivities from a ground-based research radar. Results for two case studies, a stratiform rain situation and an intense convective thunderstorm, show that the radiometrically derived profiles capture the major features of the observed vertical structure of hydrometer density.

  16. Radiometric Ages of Martian Meteorites compared to Martian Surfaces Ages

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Shih, C.-Y.

    1999-01-01

    The surprisingly young Rb-Sr age of the Shergotty meteorite contributed to early suggestions that it might be of martian origin. their redox state and oxygen isotopic compositions linked the shergottites to the clino-pyroxenite nakhlites and the dunite Chassigny, causing them to be grouped as SNC meteorites. These characteristics, but especially the similarity of the elemental and isotopic compositions of gases trapped in shergottites to those of the martian atmosphere, have caused the martian origin of the SNC and related meteorites to be widely accepted. Although the young ages were one of the early hints of a martian origin for the SNC meteorites, their interpretation has remained somewhat ambiguous. We will review the radiometric ages of the martian meteorites and attempt to place them into the context of martian surface ages.

  17. [In-flight absolute radiometric calibration of UAV multispectral sensor].

    PubMed

    Chen, Wei; Yan, Lei; Gou, Zhi-Yang; Zhao, Hong-Ying; Liu, Da-Ping; Duan, Yi-Ni

    2012-12-01

    Based on the data of the scientific experiment in Urad Front Banner for UAV Remote Sensing Load Calibration Field project, with the help of 6 hyperspectral radiometric targets with good Lambertian property, the wide-view multispectral camera in UAV was calibrated adopting reflectance-based method. The result reveals that for green, red and infrared channel, whose images were successfully captured, the linear correlation coefficients between the DN and radiance are all larger than 99%. In final analysis, the comprehensive error is no more than 6%. The calibration results demonstrate that the hyperspectral targets equipped by the calibration field are well suitable for air-borne multispectral load in-flight calibration. The calibration result is reliable and could be used in the retrieval of geophysical parameters. PMID:23427528

  18. Calculation of atmospheric loss from microwave radiometric noise temperature measurements

    NASA Technical Reports Server (NTRS)

    Stelzried, C.; Slobin, S. D.

    1981-01-01

    Microwave propagation loss in the atmosphere can be inferred from microwave radiometric noise temperature measurements. The relevant equations are given and a derivation and calculation is made assuming various physical models. Comparison is made with the commonly used lumped element atmospheric model (isothermal and uniform loss) and the model with linear temperature and exponential loss distributions. The results are useful for estimating the integral inversion differences due to the model selection. This indicates that the commonly used lumped element atmospheric model is a very good approximation with judicious choice of the effective physical temperature. For the worst case comparison, the lumped element model agrees with the variable parameter model within 0.2 dB up to a propagation loss of 3 dB.

  19. Radiometric calibration and SNR calculation of a SWIR imaging telescope

    SciTech Connect

    Yilmaz, Ozgur; Turk, Fethi; Selimoglu, Ozgur

    2012-09-06

    Radiometric calibration of an imaging telescope is usually made using a uniform illumination sphere in a laboratory. In this study, we used the open-sky images taken during bright day conditions to calibrate our telescope. We found a dark signal offset value and a linear response coefficient value for each pixel by using three different algorithms. Then we applied these coefficients to the taken images, and considerably lowered the image non-uniformity. Calibration can be repeated during the operation of telescope with an object that has better uniformity than open-sky. Also SNR (Signal to Noise Ratio) of each pixel was calculated from the open-sky images using the temporal mean and standard deviations. It is found that SNR is greater than 80 for all pixels even at low light levels.

  20. Mixing geometric and radiometric features for change classification

    NASA Astrophysics Data System (ADS)

    Fournier, Alexandre; Descombes, Xavier; Zerubia, Josiane

    2008-02-01

    Most basic change detection algorithms use a pixel-based approach. Whereas such approach is quite well defined for monitoring important area changes (such as urban growth monitoring) in low resolution images, an object based approach seems more relevant when the change detection is specifically aimed toward targets (such as small buildings and vehicles). In this paper, we present an approach that mixes radiometric and geometric features to qualify the changed zones. The goal is to establish bounds (appearance, disappearance, substitution ...) between the detected changes and the underlying objects. We proceed by first clustering the change map (containing each pixel bitemporal radiosity) in different classes using the entropy-kmeans algorithm. Assuming that most man-made objects have a polygonal shape, a polygonal approximation algorithm is then used in order to characterize the resulting zone shapes. Hence allowing us to refine the primary rough classification, by integrating the polygon orientations in the state space. Tests are currently conducted on Quickbird data.

  1. Experimental study of radiometric forces with comparison to computational results

    NASA Astrophysics Data System (ADS)

    Selden, Nathaniel P.

    A study of the radiometric forces on heated plates has been conducted both experimentally and computationally. The experiments were carried out at USC in two vacuum chambers up to a maximum pressure of 6 Pa for various carrier gases. The computations were performed with both the DSMC and ES-BGK methods for a 2-D gas flow over a comparable range of pressures. It is shown that the radiometric devices provide maximum force at a Knudsen number approximating 0.1. Of the various gases tested, helium provides the largest peak force. Qualitatively, the experimental data and computational results are similar. A lack of experimental data on gas-surface accommodation and flow three-dimensionality yields up to a 40% difference in the magnitude of the measured and computed forces, but it is shown that this discrepancy can be used to predict accommodation values. Comparison of four geometric configurations has shown that the effect of the area is significant at pressures up to where the force is maximum. It is also demonstrated that the size of the chamber in which the radiometer resides is of primary importance, where the chamber dimensions are inversely related to the generated force. Finally, simulation of multi-vane configurations have shown that the optimal spacing of vanes can be tailored for specific uses; for maximum force production a tight spacing should be used, while maximum efficiency requires spacing on the order of a vane dimension. While the results so far are encouraging, they are far from complete. Further improvements would include: a new experimental setup to reduce uncertainty with highly accurate temperature control and measurement, an in situ way to prepare the surface as well as measure its cleanliness, and an in depth iterative computational study observing the impact of multiple radiometer vanes at numerous seperations.

  2. IRCM spectral signature measurements instrumentation featuring enhanced radiometric accuracy

    NASA Astrophysics Data System (ADS)

    Lantagne, Stéphane; Prel, Florent; Moreau, Louis; Roy, Claude; Willers, Cornelius J.

    2015-10-01

    Hyperspectral Infrared (IR) signature measurements are performed in military applications including aircraft- and -naval vessel stealth characterization, detection/lock-on ranges, and flares efficiency characterization. Numerous military applications require high precision measurement of infrared signature characterization. For instance, Infrared Countermeasure (IRCM) systems and Infrared Counter-Countermeasure (IRCCM) system are continuously evolving. Infrared flares defeated IR guided seekers, IR flares became defeated by intelligent IR guided seekers and Jammers defeated the intelligent IR guided seekers [7]. A precise knowledge of the target infrared signature phenomenology is crucial for the development and improvement of countermeasure and counter-countermeasure systems and so precise quantification of the infrared energy emitted from the targets requires accurate spectral signature measurements. Errors in infrared characterization measurements can lead to weakness in the safety of the countermeasure system and errors in the determination of detection/lock-on range of an aircraft. The infrared signatures are analyzed, modeled, and simulated to provide a good understanding of the signature phenomenology to improve the IRCM and IRCCM technologies efficiency [7,8,9]. There is a growing need for infrared spectral signature measurement technology in order to further improve and validate infrared-based models and simulations. The addition of imagery to Spectroradiometers is improving the measurement capability of complex targets and scenes because all elements in the scene can now be measured simultaneously. However, the limited dynamic range of the Focal Plane Array (FPA) sensors used in these instruments confines the ranges of measurable radiance intensities. This ultimately affects the radiometric accuracy of these complex signatures. We will describe and demonstrate how the ABB hyperspectral imaging spectroradiometer features enhanced the radiometric accuracy

  3. JPSS-1 VIIRS pre-launch radiometric performance

    NASA Astrophysics Data System (ADS)

    Oudrari, Hassan; McIntire, Jeff; Xiong, Xiaoxiong; Butler, James; Efremova, Boryana; Ji, Qiang; Lee, Shihyan; Schwarting, Tom

    2015-09-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) on-board the first Joint Polar Satellite System (JPSS) completed its sensor level testing on December 2014. The JPSS-1 (J1) mission is scheduled to launch in December 2016, and will be very similar to the Suomi-National Polar-orbiting Partnership (SNPP) mission. VIIRS instrument was designed to provide measurements of the globe twice daily. It is a wide-swath (3,040 km) cross-track scanning radiometer with spatial resolutions of 370 and 740 m at nadir for imaging and moderate bands, respectively. It covers the wavelength spectrum from reflective to long-wave infrared through 22 spectral bands [0.412 μm to 12.01 μm]. VIIRS observations are used to generate 22 environmental data products (EDRs). This paper will briefly describe J1 VIIRS characterization and calibration performance and methodologies executed during the pre-launch testing phases by the independent government team, to generate the at-launch baseline radiometric performance, and the metrics needed to populate the sensor data record (SDR) Look-Up-Tables (LUTs). This paper will also provide an assessment of the sensor pre-launch radiometric performance, such as the sensor signal to noise ratios (SNRs), dynamic range, reflective and emissive bands calibration performance, polarization sensitivity, bands spectral performance, response-vs-scan (RVS), near field and stray light responses. A set of performance metrics generated during the pre-launch testing program will be compared to the SNPP VIIRS pre-launch performance.

  4. Ground-based vicarious radiometric calibration of Terra MODIS

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, J.; Thome, K.

    2009-12-01

    Accurate radiometric calibration is required by Earth-observing systems to ensure that the derived data products are of the highest quality. Preflight calibration is used as a baseline to understand the system before it is launched on orbit, while post-launch calibration is used to understand changes that may have occurred due to the nature of launching an instrument into space. On-orbit radiometric calibration ensures that changes in the system, including any onboard calibration sources, can be monitored. The Remote Sensing Group at the University of Arizona has been directly involved in the ground-based vicarious calibration of both Terra and Aqua MODIS since their respective launches in 1999 and 2002. RSG personnel are present at a test site during sensor overpass, and surface reflectance and atmospheric attenuation measurements are used as inputs to a radiative transfer code to determine the top-of-atmosphere radiance for the sensor under test. In the case of Terra MODIS, a 1-km2 site at Railroad Valley, Nevada, is used as a test site. This work presents results obtained using the reflectance-based approach at RSG’s Railroad Valley test site. Results from 10 years of in situ data collection at Railroad Valley show a percent difference in the seven land spectral channels between RSG and Terra MODIS ranging from 1.6 % in channel 6 (1632 nm), to 5.1% in channel 4 (553 nm). The average percent difference for Terra MODIS’s seven land channels and RSG is 3.5%. The uncertainty is within the 3-5% predicted for ground-based vicarious calibration.

  5. Analysis and modeling of radiometric error caused by imaging blur in optical remote sensing systems

    NASA Astrophysics Data System (ADS)

    Xie, Xufen; Zhang, Yuncui; Wang, Hongyuan; Zhang, Wei

    2016-07-01

    Imaging blur changes the digital output values of imaging systems. It leads to radiometric errors when the system is used for measurement. In this paper, we focus on the radiometric error due to imaging blur in remote sensing imaging systems. First, in accordance with the radiometric response calibration of imaging systems, we provide a theoretical analysis on the evaluation standard of radiometric errors caused by imaging blur. Then, we build a radiometric error model for imaging blur based on the natural stochastic fractal characteristics of remote sensing images. Finally, we verify the model by simulations and physical defocus experiments. The simulation results show that the modeling estimation result approaches to the simulation computation. The maximum difference of relative MSE (Mean Squared Error) between simulation computation and modeling estimation can achieve 1.6%. The physical experimental results show that the maximum difference of relative MSE between experimental results and modeling estimation is only 1.29% under experimental conditions. Simulations and experiments demonstrate that the proposed model is correct, which can be used to estimate the radiometric error caused by imaging blur in remote sensing images. This research is of great importance for radiometric measurement system evaluation and application.

  6. RapidEye constellation relative radiometric accuracy measurement using lunar images

    NASA Astrophysics Data System (ADS)

    Steyn, Joe; Tyc, George; Beckett, Keith; Hashida, Yoshi

    2009-09-01

    The RapidEye constellation includes five identical satellites in Low Earth Orbit (LEO). Each satellite has a 5-band (blue, green, red, red-edge and near infrared (NIR)) multispectral imager at 6.5m GSD. A three-axes attitude control system allows pointing the imager of each satellite at the Moon during lunations. It is therefore possible to image the Moon from near identical viewing geometry within a span of 80 minutes with each one of the imagers. Comparing the radiometrically corrected images obtained from each band and each satellite allows a near instantaneous relative radiometric accuracy measurement and determination of relative gain changes between the five imagers. A more traditional terrestrial vicarious radiometric calibration program has also been completed by MDA on RapidEye. The two components of this program provide for spatial radiometric calibration ensuring that detector-to-detector response remains flat, while a temporal radiometric calibration approach has accumulated images of specific dry dessert calibration sites. These images are used to measure the constellation relative radiometric response and make on-ground gain and offset adjustments in order to maintain the relative accuracy of the constellation within +/-2.5%. A quantitative comparison between the gain changes measured by the lunar method and the terrestrial temporal radiometric calibration method is performed and will be presented.

  7. Radiometric Normalization of Large Airborne Image Data Sets Acquired by Different Sensor Types

    NASA Astrophysics Data System (ADS)

    Gehrke, S.; Beshah, B. T.

    2016-06-01

    Generating seamless mosaics of aerial images is a particularly challenging task when the mosaic comprises a large number of im-ages, collected over longer periods of time and with different sensors under varying imaging conditions. Such large mosaics typically consist of very heterogeneous image data, both spatially (different terrain types and atmosphere) and temporally (unstable atmo-spheric properties and even changes in land coverage). We present a new radiometric normalization or, respectively, radiometric aerial triangulation approach that takes advantage of our knowledge about each sensor's properties. The current implementation supports medium and large format airborne imaging sensors of the Leica Geosystems family, namely the ADS line-scanner as well as DMC and RCD frame sensors. A hierarchical modelling - with parameters for the overall mosaic, the sensor type, different flight sessions, strips and individual images - allows for adaptation to each sensor's geometric and radiometric properties. Additional parameters at different hierarchy levels can compensate radiome-tric differences of various origins to compensate for shortcomings of the preceding radiometric sensor calibration as well as BRDF and atmospheric corrections. The final, relative normalization is based on radiometric tie points in overlapping images, absolute radiometric control points and image statistics. It is computed in a global least squares adjustment for the entire mosaic by altering each image's histogram using a location-dependent mathematical model. This model involves contrast and brightness corrections at radiometric fix points with bilinear interpolation for corrections in-between. The distribution of the radiometry fixes is adaptive to each image and generally increases with image size, hence enabling optimal local adaptation even for very long image strips as typi-cally captured by a line-scanner sensor. The normalization approach is implemented in HxMap software. It has been

  8. Radiometric Calibration Assessment of Commercial High Spatial Resolution Multispectral Image Products

    NASA Technical Reports Server (NTRS)

    Holekamp, Kara; Aaron, David; Thome, Kurtis

    2006-01-01

    Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities can better understand their properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other systems. To address this calibration need, satellite at-sensor radiance values were compared to those estimated by each independent team member to determine the sensor's radiometric accuracy. The combined results of this evaluation provide the user community with an independent assessment of these commercially available high spatial resolution sensors' absolute calibration values.

  9. Improved Radiometric Based Method for Suppressing Impulse Noise from Corrupted Images

    NASA Astrophysics Data System (ADS)

    Wu, Changcheng; Zhao, Chunyu; Chen, Dayue

    A novel filter is introduced in this paper to improve the ability of radiometric based method on suppressing impulse noise. Firstly, a new method is introduced to design the impulsive weight by measuring how impulsive a pixel is. Then, the impulsive weight is combined with the radiometric weight to obtain the evaluated values on each pixel in the whole corrupted image. The impulsive weight is mainly designed to suppress the impulse noise, while the radiometric weight is mainly designed to protect the noise-free pixel. Extensive experiments demonstrate that the proposed algorithm can perform much better than other filters in terms of the quantitative and qualitative aspects.

  10. Landsat-7 ETM+ radiometric stability and absolute calibration

    USGS Publications Warehouse

    Markham, B.L.; Barker, J.L.; Barsi, J.A.; Kaita, E.; Thome, K.J.; Helder, D.L.; Palluconi, Frank Don; Schott, J.R.; Scaramuzza, P.

    2002-01-01

    Launched in April 1999, the Landsat-7 ETM+ instrument is in its fourth year of operation. The quality of the acquired calibrated imagery continues to be high, especially with respect to its three most important radiometric performance parameters: reflective band instrument stability to better than ??1%, reflective band absolute calibration to better than ??5%, and thermal band absolute calibration to better than ??0.6 K. The ETM+ instrument has been the most stable of any of the Landsat instruments, in both the reflective and thermal channels. To date, the best on-board calibration source for the reflective bands has been the Full Aperture Solar Calibrator, which has indicated changes of at most -1.8% to -2.0% (95% C.I.) change per year in the ETM+ gain (band 4). However, this change is believed to be caused by changes in the solar diffuser panel, as opposed to a change in the instrument's gain. This belief is based partially on ground observations, which bound the changes in gain in band 4 at -0.7% to +1.5%. Also, ETM+ stability is indicated by the monitoring of desert targets. These image-based results for four Saharan and Arabian sites, for a collection of 35 scenes over the three years since launch, bound the gain change at -0.7% to +0.5% in band 4. Thermal calibration from ground observations revealed an offset error of +0.31 W/m 2 sr um soon after launch. This offset was corrected within the U. S. ground processing system at EROS Data Center on 21-Dec-00, and since then, the band 6 on-board calibration has indicated changes of at most +0.02% to +0.04% (95% C.I.) per year. The latest ground observations have detected no remaining offset error with an RMS error of ??0.6 K. The stability and absolute calibration of the Landsat-7 ETM+ sensor make it an ideal candidate to be used as a reference source for radiometric cross-calibrating to other land remote sensing satellite systems.

  11. The Landsat Data Continuity Mission Operational Land Imager: Radiometric Performance

    NASA Technical Reports Server (NTRS)

    Markham, Brian; Dabney, Philip; Pedelty, Jeffrey

    2011-01-01

    The Operational Land Imager (OLI) is one of two instruments to fly on the Landsat Data Continuity Mission (LDCM), which is scheduled to launch in December 2012 to become the 8th in the series of Landsat satellites. The OLI images in the solar reflective part of the spectrum, with bands similar to bands 1-5, 7 and the panchromatic band on the Landsat-7 ETM+ instrument. In addition, it has a 20 nm bandpass spectral band at 443 nm for coastal and aerosol studies and a 30 nm band at 1375 nm to aid in cirrus cloud detection. Like ETM+, spatial resolution is 30 m in the all but the panchromatic band, which is 15 meters. OLI is a pushbroom radiometer with approximately 6000 detectors per 30 meter band as opposed to the 16 detectors per band on the whiskbroom ETM+. Data are quantized to 12 bits on OLI as opposed to 8 bits on ETM+ to take advantage of the improved signal to noise ratio provided by the pushbroom design. The saturation radiances are higher on OLI than ETM+ to effectively eliminate saturation issues over bright Earth targets. OLI includes dual solar diffusers for on-orbit absolute and relative (detector to detector) radiometric calibration. Additionally, OLI has 3 sets of on-board lamps that illuminate the OLI focal plane through the full optical system, providing additional checks on the OLI's response[l]. OLI has been designed and built by Ball Aerospace & Technology Corp. (BATC) and is currently undergoing testing and calibration in preparation for delivery in Spring 2011. Final pre-launch performance results should be available in time for presentation at the conference. Preliminary results will be presented below. These results are based on the performance of the Engineering Development Unit (EDU) that was radiometrically tested at the integrated instrument level in 2010 and assembly level measurements made on the flight unit. Signal-to-Noise (SNR) performance: One of the advantages of a pushbroom system is the increased dwell time of the detectors

  12. Radiometric-microbiologic assay fo vitamin B-6: analysis of plasma samples

    SciTech Connect

    Guilarte, T.R.; McIntyre, P.A.

    1981-11-01

    A radiometric microbiologic assay for the analysis of vitamin B-6 in plasma was developed. The method is based on the measurement of 14CO2 generated from the metabolism of DL-l-14C-valine (L-l-14C-valine) by Kloeckera brevis. The assay is specific for the biologically active forms of the vitamin, that is, pyridoxine, pyridoxal and pyridoxamine, and their respective phosphorylated forms. The biologically inert vitamin B-6 metabolite (4-pyridoxic acid) did not generate a response at concentrations tested. The radiometric technique was shown to be sensitive to the 1 nanogram level. Reproducibility and recovery studies gave good results. Fifteen plasma samples were assayed using the radiometric and turbidimetric techniques. The correlation coefficient was r . 0.98. Turbid material or precipitated debris did not interfere with the radiometric microbiologic assay, thus allowing for simplification of assay procedure.

  13. Susceptibility testing of filamentous fungi to amphotericin B by a rapid radiometric method

    SciTech Connect

    Merz, W.G.; Fay, D.; Thumar, B.; Dixon, D.

    1984-01-01

    A rapid, radiometric method was developed to determine the susceptibility of filamentous fungi to amphotericin B. The rapid, radiometric method depended on measurement of the inhibition of /sup 24/CO/sub 2/ production in the presence of amphotericin B. Thirty isolates of filamentous fungi were tested by the rapid, radiometric method and a reference agar dilution method. There was 93% agreement between the two methods when an 80% or greater decrease in CO/sub 2/ production was used to calculate the minimal inhibitory concentration with the rapid, radiometric method. Minimal inhibitory concentrations, based on 80% decrease of CO/sub 2/ production, were achieved within 24 h of incubation with all of the fungi tested.

  14. Flight Technology Improvement. [spaceborne optical radiometric instruments, attitude control, and electromechanical and power subsystems

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Shortcomings in spaceborne instrumentation technology are analyzed and recommendations are given for corrections and technology development. The technologies discussed are optical radiometric instruments and calibration, attitude control and determination, and electromechanical and power subsystems.

  15. Intra-annual NDVI validation of the Landsat 5 TM radiometric calibration

    USGS Publications Warehouse

    Chander, G.; Groeneveld, D.P.

    2009-01-01

    Multispectral data from the Landsat 5 (L5) Thematic Mapper (TM) sensor provide the backbone of the extensive archive of moderate-resolution Earth imagery. Even after more than 24 years of service, the L5 TM is still operational. Given the longevity of the satellite, the detectors have aged and the sensor's radiometric characteristics have changed since launch. The calibration procedures and parameters in the National Land Archive Production System (NLAPS) have also changed with time. Revised radiometric calibrations in 2003 and 2007 have improved the radiometric accuracy of recently processed data. This letter uses the Normalized Difference Vegetation Index (NDVI) as a metric to evaluate the radiometric calibration. The calibration change has improved absolute calibration accuracy, consistency over time, and consistency with Landsat 7 (L7) Enhanced Thematic radiometry and will provide the basis for continued long-term studies of the Earth's land surfaces.

  16. Radiometric absolute noise-temperature measurement system features improved accuracy and calibration ease

    NASA Technical Reports Server (NTRS)

    Brown, W.; Ewen, H.; Haroules, G.

    1970-01-01

    Radiometric receiver system, which measures noise temperatures in degrees Kelvin, does not require cryogenic noise sources for routine operation. It eliminates radiometer calibration errors associated with RF attenuation measurements. Calibrated noise source is required only for laboratory adjustment and calibration.

  17. Advanced radiometric complex for detection of radioactive release from Siberian chemical combine

    NASA Astrophysics Data System (ADS)

    Kolotkov, Gennady A.; Penin, Sergei T.

    2015-11-01

    The paper states limited availability of the use of the automated radiation situation monitoring system and proposes radiometric complex as more reliable system in the case of an accidental release of the Siberian Chemical Enterprises.

  18. Experimental Research on Passive Millimeter Wave Radiometric Stealth Technology of Metal Objects

    NASA Astrophysics Data System (ADS)

    Zhang, Guangfeng; Lou, Guowei; Li, Xingguo

    2012-12-01

    Working all day and all weather, a passive millimeter wave radiometer (PMMW) can be widely used in civil and military affairs. It can get some specific information about the material characteristics different from radar and infrared detectors. On basis of the radiometric operating range equation, the radiation cross section and stealth effect of metal objects are presented for the PMMW near-sensing application. The measurement experiments of metal solid models adopts 3 mm band Dicke radiometer with the outdoor calibration system. The sky temperature and other different surface metal objects are also measured as the contrastive experiments. The results show the radiometric temperature contrasts of solid models have remarkable difference in the bare and coated conditions, and the radiometric operating range can decrease to 60.8 %. In addition, the PMMW stealth methods through different surface treatment respectively reduce the radiometric antenna temperature contrast in some degree.

  19. Study of Spectral/Radiometric Characteristics of the Thematic Mapper for Land Use Applications

    NASA Technical Reports Server (NTRS)

    Malila, W. A. (Principal Investigator); Metzler, M. D. (Principal Investigator)

    1985-01-01

    An investigation conducted in support of the LANDSAT 4/5 Image Data Quality Analysis (LIDQA) Program is discussed. Results of engineering analyses of radiometric, spatial, spectral, and geometric properties of the Thematic Mapper systems are summarized; major emphasis is placed on the radiometric analysis. Details of the analyses are presented in appendices, which contain three of the eight technical papers produced during this investigation; these three, together, describe the major activities and results of the investigation.

  20. Phoretic and Radiometric Force Measurements on Microparticles in Microgravity Conditions

    NASA Technical Reports Server (NTRS)

    Davis, E. James

    1996-01-01

    Thermophoretic, diffusiophoretic and radiometric forces on microparticles are being measured over a wide range of gas phase and particle conditions using electrodynamic levitation of single particles to simulate microgravity conditions. The thermophoretic force, which arises when a particle exists in a gas having a temperature gradient, is measured by levitating an electrically charged particle between heated and cooled plates mounted in a vacuum chamber. The diffusiophoretic force arising from a concentration gradient in the gas phase is measured in a similar manner except that the heat exchangers are coated with liquids to establish a vapor concentration gradient. These phoretic forces and the radiation pressure force acting on a particle are measured directly in terms of the change in the dc field required to levitate the particle with and without the force applied. The apparatus developed for the research and the experimental techniques are discussed, and results obtained by thermophoresis experiments are presented. The determination of the momentum and energy accommodation coefficients associated with molecular collisions between gases molecules and particles and the measurement of the interaction between electromagnetic radiation and small particles are of particular interest.

  1. JPSS-1 VIIRS pre-launch radiometric performance

    NASA Astrophysics Data System (ADS)

    Oudrari, Hassan; McIntire, Jeff; Xiong, Xiaoxiong; Butler, James; Ji, Qiang; Schwarting, Tom; Zeng, Jinan

    2016-05-01

    The first Joint Polar Satellite System (JPSS-1 or J1) mission is scheduled to launch in January 2017, and will be very similar to the Suomi-National Polar-orbiting Partnership (SNPP) mission. The Visible Infrared Imaging Radiometer Suite (VIIRS) on board the J1 spacecraft completed its sensor level performance testing in December 2014. VIIRS instrument is expected to provide valuable information about the Earth environment and properties on a daily basis, using a wide-swath (3,040 km) cross-track scanning radiometer. The design covers the wavelength spectrum from reflective to long-wave infrared through 22 spectral bands, from 0.412 μm to 12.01 μm, and has spatial resolutions of 370 m and 740 m at nadir for imaging and moderate bands, respectively. This paper will provide an overview of pre-launch J1 VIIRS performance testing and methodologies, describing the at-launch baseline radiometric performance as well as the metrics needed to calibrate the instrument once on orbit. Key sensor performance metrics include the sensor signal to noise ratios (SNRs), dynamic range, reflective and emissive bands calibration performance, polarization sensitivity, bands spectral performance, response-vs-scan (RVS), near field response, and stray light rejection. A set of performance metrics generated during the pre-launch testing program will be compared to the sensor requirements and to SNPP VIIRS pre-launch performance.

  2. Radiometric STFT Analysis of PDV recordings and detectivity limit

    NASA Astrophysics Data System (ADS)

    Bozier, Olivier; Prudhomme, Gabriel; Mercier, Patrick; Berthe, Laurent

    2015-06-01

    Photonic Doppler Velocimetry is a plug-and-play and versatile diagnostic used in dynamic physic experiments to measure velocities. When signals are analyzed using a Short-Time Fourier Transform, multiple velocities can be distinguished: by example, the velocities of moving particle-cloud appear on spectrograms. In order to estimate the back-scattering fluxes of target, we propose an original approach ``PDV Radiometric analysis'' resulting in an expression of time-velocity spectrograms coded in power units. Experiments involving micron-sized particles raise the issue of detection limit; particle-size limit is very difficult to evaluate. From the quantification of noise sources, we derivate an estimation of the spectrogram noise leading to a detectivity limit. It may be compared to back-scattering and collected power from a particle, which is increasing with its size. At least, some results from laser-shock accelerated particles using two different PDV systems are compared: it may show the improvement of sensitivity.

  3. A hyperspectral imager for high radiometric accuracy Earth climate studies

    NASA Astrophysics Data System (ADS)

    Espejo, Joey; Drake, Ginger; Heuerman, Karl; Kopp, Greg; Lieber, Alex; Smith, Paul; Vermeer, Bill

    2011-10-01

    We demonstrate a visible and near-infrared prototype pushbroom hyperspectral imager for Earth climate studies that is capable of using direct solar viewing for on-orbit cross calibration and degradation tracking. Direct calibration to solar spectral irradiances allow the Earth-viewing instrument to achieve required climate-driven absolute radiometric accuracies of <0.2% (1σ). A solar calibration requires viewing scenes having radiances 105 higher than typical Earth scenes. To facilitate this calibration, the instrument features an attenuation system that uses an optimized combination of different precision aperture sizes, neutral density filters, and variable integration timing for Earth and solar viewing. The optical system consists of a three-mirror anastigmat telescope and an Offner spectrometer. The as-built system has a 12.2° cross track field of view with 3 arcmin spatial resolution and covers a 350-1050 nm spectral range with 10 nm resolution. A polarization compensated configuration using the Offner in an out of plane alignment is demonstrated as a viable approach to minimizing polarization sensitivity. The mechanical design takes advantage of relaxed tolerances in the optical design by using rigid, non-adjustable diamond-turned tabs for optical mount locating surfaces. We show that this approach achieves the required optical performance. A prototype spaceflight unit is also demonstrated to prove the applicability of these solar cross calibration methods to on-orbit environments. This unit is evaluated for optical performance prior to and after GEVS shake, thermal vacuum, and lifecycle tests.

  4. History of Solar Radiometry and the World Radiometric Reference

    NASA Astrophysics Data System (ADS)

    Fröhlich, C.

    1991-01-01

    The history of solar radiometry since the first pyrheliometer of Pouillet is presented. After the invention of the Ångström and the Smithsonian pyrheliometers around the turn of this century two different "scales" were in use. Comparisons with absolute cavity radiometers developed in America and Europe have been performed since about 1910 which show remarkably accurate measurements in terms of the SI units. However, these results have never been accepted and several rules have been established to reference radiation measurements in the meteorological community and to remedy the unsatisfactory fact of having different "scales". Unfortunately none of these rules led to a reference close to the SI units of irradiance, confusing the issue even more. With the advent of modern absolute radiometers in the late 1960s the situation improved and led to the definition of the World Radiometric Reference in use by the meteorological community since 1981. This reference has an estimated accuracy of 0,3% and guarantees the worldwide homogeneity of radiation measurements within 0,1% precision.

  5. Laser photothermal radiometric instrument for industrial steel hardness inspection

    NASA Astrophysics Data System (ADS)

    Guo, X.; Sivagurunathan, K.; Pawlak, M.; Garcia, J.; Mandelis, A.; Giunta, S.; Milletari, S.; Bawa, S.

    2010-03-01

    To meet the industrial demand for on-line steel hardness inspection and quality control, a non-contact, non-destructive laser photothermal radiometric instrument (HD-PTR) was developed. The instrument is equipped with a non-liquid-nitrogen-cooled HgCdZnTe (MCZT) detector, a National Instruments data acquisition card with a Dynamic System Analysis (DSA) module, and control software. A series of industrial steel samples which included automotive screws and aircraft gears (flat or curvilinear) were examined. The effective hardness case depths of these samples ranged from 0.21 mm to 1.78 mm. The results demonstrated that three measurement parameters (metrics) can be extracted when using a fast swept-sine photothermal method. These parameters include the phase minimum (or peak) frequency, fmin, the half width, W, and the area, S. It was found that they are complementary for evaluating widely different ranges of hardness case depths. fminis most suitable for large case depths, and W and S for shallower case depths.

  6. Understanding Satellite Characterization Knowledge Gained from Radiometric Data

    NASA Astrophysics Data System (ADS)

    Harms, A.; Hamada, K.; Wetterer, C.; Luu, K.; Sabol, C.; Alfriend, K.

    2011-09-01

    This paper presents a framework for determining satellite characterization knowledge, in the form of estimated parameter uncertainties, from radiometric observation type, quantity, quality, and in combinations. The approach combines complex forward modeling capability with an Unscented Kalman Filter (UKF) to map observation uncertainties into satellite characterization parameter space. These parameters can include size, shape, orientation, material properties, etc., and the observations can include broadband or narrowband spectral radiometry, spatially resolved or non-resolved imagery, and passive or active optical data. In order to demonstrate the effectiveness of the technique, the example of using photometric light curve observations to estimate the orientation of a cube is presented. This example is chosen since the orientation uncertainty can be analytically traced from basic radiometry equations and compared to the results of the UKF. The uncertainties can also be tested through Monte Carlo analysis in which simulations are performed 10 times in order to compare observed estimation error sample statistics to the uncertainty predicted by the UKF. There are many optical sensors available and proposed to provide satellite characterization information. Understanding the information content in these data, which this approach provides, allows users to predict the amount and type of data required to obtain desired satellite characterization knowledge as well as provides direction for high pay-off future sensor development efforts.

  7. Early detection of RFI in SMOS radiometric measurements

    NASA Astrophysics Data System (ADS)

    Anterrieu, Eric

    2011-10-01

    The SMOS mission is a European Space Agency (ESA) project aimed at global monitoring of surface Soil Moisture and Ocean Salinity from radiometric L-band observations. The single payload of the mission is MIRAS, the very first Microwave Imaging Radiometer using Aperture Synthesis ever launched into space. This work is concerned with the contamination of the data collected by MIRAS by radio frequency interferences (RFI) which degrade the performance of the mission. RFI events are evidenced and it is explained why well-known standard RFI detection methods cannot be used. Accounting for specificities of MIRAS, an early detection method tailored to SMOS measurements is presented and illustrated with data acquired with the reference radiometers during the first year of the mission. The aim of this method is not to localize nor to quantify the RFI sources but only to detect, to quantify and possibly to mitigate the corresponding RFI effects in the signals measured by these radiometers. This is done as soon as possible in the processing pipeline so that the propagation of such undesirable effects is known and under control from measurements to final products.

  8. Advanced radiometric and interferometric milimeter-wave scene simulations

    NASA Technical Reports Server (NTRS)

    Hauss, B. I.; Moffa, P. J.; Steele, W. G.; Agravante, H.; Davidheiser, R.; Samec, T.; Young, S. K.

    1993-01-01

    Smart munitions and weapons utilize various imaging sensors (including passive IR, active and passive millimeter-wave, and visible wavebands) to detect/identify targets at short standoff ranges and in varied terrain backgrounds. In order to design and evaluate these sensors under a variety of conditions, a high-fidelity scene simulation capability is necessary. Such a capability for passive millimeter-wave scene simulation exists at TRW. TRW's Advanced Radiometric Millimeter-Wave Scene Simulation (ARMSS) code is a rigorous, benchmarked, end-to-end passive millimeter-wave scene simulation code for interpreting millimeter-wave data, establishing scene signatures and evaluating sensor performance. In passive millimeter-wave imaging, resolution is limited due to wavelength and aperture size. Where high resolution is required, the utility of passive millimeter-wave imaging is confined to short ranges. Recent developments in interferometry have made possible high resolution applications on military platforms. Interferometry or synthetic aperture radiometry allows the creation of a high resolution image with a sparsely filled aperture. Borrowing from research work in radio astronomy, we have developed and tested at TRW scene reconstruction algorithms that allow the recovery of the scene from a relatively small number of spatial frequency components. In this paper, the TRW modeling capability is described and numerical results are presented.

  9. Advanced radiometric and interferometric milimeter-wave scene simulations

    NASA Astrophysics Data System (ADS)

    Hauss, B. I.; Moffa, P. J.; Steele, W. G.; Agravante, H.; Davidheiser, R.; Samec, T.; Young, S. K.

    1993-12-01

    Smart munitions and weapons utilize various imaging sensors (including passive IR, active and passive millimeter-wave, and visible wavebands) to detect/identify targets at short standoff ranges and in varied terrain backgrounds. In order to design and evaluate these sensors under a variety of conditions, a high-fidelity scene simulation capability is necessary. Such a capability for passive millimeter-wave scene simulation exists at TRW. TRW's Advanced Radiometric Millimeter-Wave Scene Simulation (ARMSS) code is a rigorous, benchmarked, end-to-end passive millimeter-wave scene simulation code for interpreting millimeter-wave data, establishing scene signatures and evaluating sensor performance. In passive millimeter-wave imaging, resolution is limited due to wavelength and aperture size. Where high resolution is required, the utility of passive millimeter-wave imaging is confined to short ranges. Recent developments in interferometry have made possible high resolution applications on military platforms. Interferometry or synthetic aperture radiometry allows the creation of a high resolution image with a sparsely filled aperture. Borrowing from research work in radio astronomy, we have developed and tested at TRW scene reconstruction algorithms that allow the recovery of the scene from a relatively small number of spatial frequency components. In this paper, the TRW modeling capability is described and numerical results are presented.

  10. Robust Multiscale Stereo Matching from Fundus Images with Radiometric Differences

    PubMed Central

    Tang, Li; Garvin, Mona K.; Lee, Kyungmoo; Alward, Wallace L.M.; Kwon, Young H.; Abràmoff, Michael D.

    2013-01-01

    A robust multiscale stereo matching algorithm is proposed to find reliable correspondences between low contrast and weakly textured retinal image pairs with radiometric differences. Existing algorithms designed to deal with piecewise planar surfaces with distinct features and Lambertian reflectance do not apply in applications such as 3D reconstruction of medical images including stereo retinal images. In this paper, robust pixel feature vectors are formulated to extract discriminative features in the presence of noise in scale space, through which the response of low-frequency mechanisms alter and interact with the response of high-frequency mechanisms. The deep structures of the scene are represented with the evolution of disparity estimates in scale space, which distributes the matching ambiguity along the scale dimension to obtain globally coherent reconstructions. The performance is verified both qualitatively by face validity and quantitatively on our collection of stereo fundus image sets with ground truth, which have been made publicly available as an extension of standard test images for performance evaluation. PMID:21464502

  11. Radiometric sensitivity contrast metrics for hyperspectral remote sensors

    NASA Astrophysics Data System (ADS)

    Silny, John F.; Zellinger, Lou

    2014-09-01

    This paper discusses the calculation, interpretation, and implications of various radiometric sensitivity metrics for Earth-observing hyperspectral imaging (HSI) sensors. The most commonly used sensor performance metric is signal-to-noise ratio (SNR), from which additional noise equivalent quantities can be computed, including: noise equivalent spectral radiance (NESR), noise equivalent delta reflectance (NEΔρ), noise equivalent delta emittance (NEΔƐ), and noise equivalent delta temperature (NEΔT). For hyperspectral sensors, these metrics are typically calculated from an at-aperture radiance (typically generated by MODTRAN) that includes both target radiance and non-target (atmosphere and background) radiance. Unfortunately, these calculations treat the entire at-aperture radiance as the desired signal, even when the target radiance is only a fraction of the total (such as when sensing through a long or optically dense atmospheric path). To overcome this limitation, an augmented set of metrics based on contrast signal-to-noise ratio (CNSR) is developed, including their noise equivalent counterparts (CNESR, CNEΔρ, CNEΔƐ, and CNEΔT). These contrast metrics better quantify sensor performance in an operational environment that includes remote sensing through the atmosphere.

  12. Radiometric oil well assay for glucokinase in microscopic structures

    SciTech Connect

    Bedoya, F.J.; Meglasson, M.D.; Wilson, J.M.; Matschinsky, F.M.

    1985-02-01

    Glucokinase plays a pivotal role in hepatic glucose metabolism and serves as the glucose sensor in pancreatic islet beta-cells. Biochemical studies of this enzyme are complicated by the cellular heterogeneity of the liver and the pancreas and because the presence of hexokinases seriously interferes with currently available analytical procedures. A radiometric assay was designed to deal with these problems. It is based on the liberation of /sup 3/H/sub 2/O from D-(2-/sup 3/H(N))glucose 6-phosphate, the product of the glucokinase reaction, using exogenous phosphoglucose isomerase. Interference by hexokinases was largely eliminated by using glucose 6-phosphate as inhibitor and the sensitivity of the assay was greatly increased by using small volumes with the oil well procedure. The assay was sufficiently sensitive to detect about 1 pg of glucokinase. It thus allowed the application of quantitative histochemical procedures to the study of intralobular hepatic glucokinase profiles and the pancreatic beta-cell glucose sensor. The quantitative histochemical procedures were sufficiently sensitive and reliable for measuring important kinetic constants of glucokinase in microscopic samples of tissue.

  13. NERO: General concept of a NEO radiometric observatory

    NASA Astrophysics Data System (ADS)

    Cellino, A.; Somma, R.; Tommasi, L.; Paolinetti, R.; Muinonen, K.; Virtanen, J.; Tedesco, E. F.

    NERO (Near-Earth Objects Radiometric Observatory) is one of the six studies for possible missions dedicated to near-Earth objects, that were funded by the ESA in 2002-2003. NERO is a further development of previous studies already submitted to ESA (Sysiphos,Spaceguard-1). The general concept is that a small satellite equipped with both a CCD for visible wavelengths and an array for thermal IR measurements around 10 microns would be an ideal platform for simultaneously obtaining two of the major objectives of current NEO science, namely the physical characterization of the objects and the discovery of NEOs which are difficult to detect because they have orbits entirely or partly interior to the Earth's orbit. The NERO study included a comprehensive analysis of the advantages and drawbacks of different orbital options for the satellite (including L2 of Earth and L2 of Venus) and a preliminary simulation of the effectiveness in deriving reliable orbits of the newly detected objects. The main results of this study, including also a preliminary design of the payload (optics, detectors, cooling system, etc.) are briefly summarized.

  14. Investigation of Aerodynamic and Aerodynamic and Radiometric Land Surface Temperatures

    NASA Technical Reports Server (NTRS)

    Crago, Richard D.; Friedl, Mark; Kustas, William; Wang, Ye-Qiao

    2003-01-01

    The overall goal of the project was to reconcile the difference between T(sub s,r) and T(sub aero), while maintaining consistency within models and with theory and data. The project involved collaboration between researchers at Bucknell University, Boston University, University of mode Island, and the USDNARS Hydrology Laboratory. This report focuses on the work done at Bucknell, which used an analytical continuous-source flux model developed by Crago (1998), based on work by Brutsaert and Sugita (1996) to generate fluxes at all levels of the canopy. Named ALARM [Analytical Land- Atmosphere-Radiometer Model] by Suleiman and Crago (2002), the model assumes the foliage has an exponential vertical temperature profile. The same profile is felt by the within-canopy turbulence and 'seen" by a radiometer viewing the surface from any zenith view angle. ALARM converts radiometric surface temperatures taken from any view angle into a clearly-defined version of Taero called the equivalent isothermal surface temperature T(sub s,j), and then calculates the sensible heat flux H using Monin-Obukhov similarity theory. This allows remotely sensed Ts,r measurements to be used to produce high quality sensible and latent heat flux estimates, or to validate or update the surface temperature produced by SVATs in climate or mesoscale models.

  15. Design, manufacture, and calibration of infrared radiometric blackbody sources

    SciTech Connect

    Byrd, D.A.; Michaud, F.D.; Bender, S.C.

    1996-04-01

    A Radiometric Calibration Station (RCS) is being assembled at the Los Alamos National Laboratories (LANL) which will allow for calibration of sensors with detector arrays having spectral capability from about 0.4-15 {mu}m. The configuration of the LANL RCS. Two blackbody sources have been designed to cover the spectral range from about 3-15 {mu}m, operating at temperatures ranging from about 180-350 K within a vacuum environment. The sources are designed to present a uniform spectral radiance over a large area to the sensor unit under test. The thermal uniformity requirement of the blackbody cavities has been one of the key factors of the design, requiring less than 50 mK variation over the entire blackbody surface to attain effective emissivity values of about 0.999. Once the two units are built and verified to the level of about 100 mK at LANL, they will be sent to the National Institute of Standards and Technology (NIST), where at least a factor of two improvement will be calibrated into the blackbody control system. The physical size of these assemblies will require modifications of the existing NIST Low Background Infrared (LBIR) Facility. LANL has constructed a bolt-on addition to the LBIR facility that will allow calibration of our large aperture sources. Methodology for attaining the two blackbody sources at calibrated levels of performance equivalent to present state of the art will be explained in the following.

  16. A multi-channel radiometric profiler of temperature, humidity and cloud liquid.

    SciTech Connect

    Ware, R.; Carpenter, R.; Guldner, J.; Liljegren, J.; Nehrkorn, T.; Solheim, F.; Vandenberghe, F.; Environmental Research; Radiometrics Corp.; Univ. Corp. for Atmospheric Research; Weather Decision Technologies Inc.; Atmospheric and Environmental Research Inc.; National Center for Atmospheric Research

    2003-07-31

    A microwave radiometer is described that provides continuous thermodynamic (temperature, water vapor, and moisture) soundings during clear and cloudy conditions. The radiometric profiler observes radiation intensity at 12 microwave frequencies, along with zenith infrared and surface meteorological measurements. Historical radiosonde and neural network or regression methods are used for profile retrieval. We compare radiometric, radiosonde, and forecast soundings and evaluate the accuracy of radiometric temperature and water vapor soundings on the basis of statistical comparison with radiosonde soundings. We find that radiometric soundings are equivalent in accuracy to radiosonde soundings when used in numerical weather forecasting. A case study is described that demonstrates improved fog forecasting on the basis of variational assimilation of radiometric soundings. The accuracy of radiometric cloud liquid soundings is evaluated by comparison with cloud liquid sensors carried by radiosondes. Accurate high-resolution three-dimensional water vapor and wind analysis is described on the basis of assimilation of simulated thermodynamic and wind soundings along with GPS slant delays. Examples of mobile thermodynamic and wind profilers are shown. Thermodynamic profiling, particularly when combined with wind profiling and slant GPS, provides continuous atmospheric soundings for improved weather and dispersion forecasting.

  17. Five-hour diagnosis of dermatophyte nail infections with specific detection of Trichophyton rubrum.

    PubMed

    Brillowska-Dabrowska, Anna; Saunte, Ditte Marie; Arendrup, Maiken Cavling

    2007-04-01

    A rapid two-step DNA extraction method and a multiplex PCR for the detection of dermatophytes in general and Trichophyton rubrum specifically were developed and evaluated with DNA extracted from pure cultures and from clinically diseased nails. DNA from the following dermatophytes was used: Epidermophyton floccosum, Microsporum audouinii, Microsporum canis, Microsporum gypseum, Microsporum nanum, Trichophyton mentagrophytes, Trichophyton rubrum, Trichophyton schoenleinii, Trichophyton soudanense, Trichophyton terrestre, Trichophyton tonsurans, Trichophyton verrucosum, and Trichophyton violaceum. Human DNA and DNA from the following nondermatophyte fungi were included as controls: Alternaria, Aspergillus niger, Candida albicans, Candida glabrata, Candida krusei, Malassezia furfur, Saccharomyces cerevisiae, and Scopulariopsis brevicaulis. A total of 118 nail samples received for routine microscopy and culture for dermatophytes were subsequently tested by the two PCRs separately and in a multiplex format. Using DNA extracted from pure cultures and the pan-dermatophyte PCR, the T. rubrum-specific PCR sequentially and in a multiplex format correctly detected all dermatophytes and additionally correctly identified T. rubrum. Comparison of the traditional diagnostic evaluation (microscopy and culture) of nail samples with PCR on DNA directly extracted from the nails showed excellent agreement between PCR and microscopy, but the number of samples with dermatophyte species identification was increased considerably from 22.9% to 41.5%, mainly due to the identification of T. rubrum by PCR in microscopy-positive but culture-negative samples. In conclusion, this 5-hour diagnostic test was shown to increase not only the speed but also the sensitivity of investigation for nail dermatophytosis. PMID:17267633

  18. Physiological adjustments of young men to five-hour desert walks.

    PubMed

    Dill, D B; Soholt, L F; Oddershede, I B

    1976-02-01

    Seven young men undertook a desert walk of 30 km at a rate of 100 m/min. Six finished; the seventh stopped after 24 km. Each satisfied his thirst with cool tap water each hour. Periodic observations included metabolic rate, blood pressure, heart rate, rectal and skin temperature, body weight, and volume of water drunk. Hand sweat was collected each hour and body sweat residues on the skin were collected at the end of the walk. Subjective reports revealed portents of breakdown: aching muscles, painful joints, hot or blistered feet, hunger, and boredom. Cardiovascular adjustment and temperature regulation maintained tolerable conditions. The volumes of water evaporated by the 5-h walkers were about the same. Wet bulb temperatures were below 25 degrees C; all sweat evaporated and was available for temperature regulation. The volume of water drawn from body reserves was closely correlated with concentration of chloride in body sweat; the volume of water that satisfied thirst maintained osmotic pressure. PMID:1249002

  19. Evaluation of three gentamicin serum assay techniques

    SciTech Connect

    Matzke, G.R.; Gwizdala, C.; Wery, J.; Ferry, D.; Starnes, R.

    1982-01-01

    This investigation was designed to compare the enzyme-modified immunoassay (Syva--EMIT) with a radioimmunoassay (New England Nuclear--RIA) and the radiometric assay (Johnston--BACTEC) to determine the optimal assay for use in our aminoglycoside dosing service. The serum concentration determinations obtained via the three assay methods were analyzed by linear regression analysis. Significant positive correlations were noted between the three assay techniques (p less than 0.005) during both sample collection phases. The coefficients of determination for EMIT vs BACTEC and RIA vs BACTEC were 0.73 and 0.83 during phase 1, respectively, and 0.65 and 0.68 during phase 2, respectively. The slope of the regression lines also varied markedly during the two phases; 0.49 and 0.42 for EMIT and for RIA vs BACTEC, respectively, during phase 1 compound with 1.12 and 0.77, respectively, during phase 2. The differences noted in these relationships during phase 1 and 2 may be related to the alteration of the pH of the control sera utilized in the BACTEC assay. In contrast, RIA vs EMIT regression analysis indicated that existence of a highly significant relationship (p less than 0.0005 and r2 . 0.90). The EMIT technique was the easiest and most accurate for determination of serum gentamicin concentrations, whereas the BACTEC method was judged unacceptable for clinical use.

  20. Serum herpes simplex antibodies

    MedlinePlus

    ... gov/ency/article/003352.htm Serum herpes simplex antibodies To use the sharing features on this page, please enable JavaScript. Serum herpes simplex antibodies is a blood test that looks for antibodies ...

  1. Serum free hemoglobin test

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003677.htm Serum free hemoglobin test To use the sharing features on this page, please enable JavaScript. Serum free hemoglobin is a blood test that measures the ...

  2. Radiometric Calibration of the Earth Observing System's Imaging Sensors

    NASA Technical Reports Server (NTRS)

    Slater, Philip N. (Principal Investigator)

    1997-01-01

    The work on the grant was mainly directed towards developing new, accurate, redundant methods for the in-flight, absolute radiometric calibration of satellite multispectral imaging systems and refining the accuracy of methods already in use. Initially the work was in preparation for the calibration of MODIS and HIRIS (before the development of that sensor was canceled), with the realization it would be applicable to most imaging multi- or hyper-spectral sensors provided their spatial or spectral resolutions were not too coarse. The work on the grant involved three different ground-based, in-flight calibration methods reflectance-based radiance-based and diffuse-to-global irradiance ratio used with the reflectance-based method. This continuing research had the dual advantage of: (1) developing several independent methods to create the redundancy that is essential for the identification and hopefully the elimination of systematic errors; and (2) refining the measurement techniques and algorithms that can be used not only for improving calibration accuracy but also for the reverse process of retrieving ground reflectances from calibrated remote-sensing data. The grant also provided the support necessary for us to embark on other projects such as the ratioing radiometer approach to on-board calibration (this has been further developed by SBRS as the 'solar diffuser stability monitor' and is incorporated into the most important on-board calibration system for MODIS)- another example of the work, which was a spin-off from the grant funding, was a study of solar diffuser materials. Journal citations, titles and abstracts of publications authored by faculty, staff, and students are also attached.

  3. Reintroducing radiometric surface temperature into the Penman-Monteith formulation

    NASA Astrophysics Data System (ADS)

    Mallick, Kaniska; Boegh, Eva; Trebs, Ivonne; Alfieri, Joseph G.; Kustas, William P.; Prueger, John H.; Niyogi, Dev; Das, Narendra; Drewry, Darren T.; Hoffmann, Lucien; Jarvis, Andrew J.

    2015-08-01

    Here we demonstrate a novel method to physically integrate radiometric surface temperature (TR) into the Penman-Monteith (PM) formulation for estimating the terrestrial sensible and latent heat fluxes (H and λE) in the framework of a modified Surface Temperature Initiated Closure (STIC). It combines TR data with standard energy balance closure models for deriving a hybrid scheme that does not require parameterization of the surface (or stomatal) and aerodynamic conductances (gS and gB). STIC is formed by the simultaneous solution of four state equations and it uses TR as an additional data source for retrieving the "near surface" moisture availability (M) and the Priestley-Taylor coefficient (α). The performance of STIC is tested using high-temporal resolution TR observations collected from different international surface energy flux experiments in conjunction with corresponding net radiation (RN), ground heat flux (G), air temperature (TA), and relative humidity (RH) measurements. A comparison of the STIC outputs with the eddy covariance measurements of λE and H revealed RMSDs of 7-16% and 40-74% in half-hourly λE and H estimates. These statistics were 5-13% and 10-44% in daily λE and H. The errors and uncertainties in both surface fluxes are comparable to the models that typically use land surface parameterizations for determining the unobserved components (gS and gB) of the surface energy balance models. However, the scheme is simpler, has the capabilities for generating spatially explicit surface energy fluxes and independent of submodels for boundary layer developments. This article was corrected on 27 AUG 2015. See the end of the full text for details.

  4. Radiometric Calibration Techniques for Signal-of-Opportunity Reflectometers

    NASA Technical Reports Server (NTRS)

    Piepmeier, Jeffrey R.; Shah, Rashmi; Deshpande, Manohar; Johnson, Carey

    2014-01-01

    Bi-static reflection measurements utilizing global navigation satellite service (GNSS) or other signals of opportunity (SoOp) can be used to sense ocean and terrestrial surface properties. End-to-end calibration of GNSS-R has been performed using well-characterized reflection surface (e.g., water), direct path antenna, and receiver gain characterization. We propose an augmented approach using on-board receiver electronics for radiometric calibration of SoOp reflectometers utilizing direct and reflected signal receiving antennas. The method calibrates receiver and correlator gains and offsets utilizing a reference switch and common noise source. On-board electronic calibration sources, such as reference switches, noise diodes and loop-back circuits, have shown great utility in stabilizing total power and correlation microwave radiometer and scatterometer receiver electronics in L-band spaceborne instruments. Application to SoOp instruments is likely to bring several benefits. For example, application to provide short and long time scale calibration stability of the direct path channel, especially in low signal-to-noise ratio configurations, is directly analogous to the microwave radiometer problem. The direct path channel is analogous to the loopback path in a scatterometer to provide a reference of the transmitted power, although the receiver is independent from the reflected path channel. Thus, a common noise source can be used to measure the gain ratio of the two paths. Using these techniques long-term (days to weeks) calibration stability of spaceborne L-band scatterometer and radiometer has been achieved better than 0.1. Similar long-term stability would likely be needed for a spaceborne reflectometer mission to measure terrestrial properties such as soil moisture.

  5. Landsat-7 EMT+ On-Orbit Radiometric Calibration

    NASA Technical Reports Server (NTRS)

    Markham, Brian L.; Barker, J. L.; Kaita, E.; Seiferth, J.; Morfitt, Ron

    1999-01-01

    Landsat-7 was launched on April 15, 1999 and completed its on orbit initialization and verification period on June 28, 1999. The ETM+ payload is similar to the TM sensors on previous Landsat satellites and incorporates two new devices to improve its absolute radiometric calibration. The Full Aperture Solar Calibrator (FASC) is a deployable diffuser panel. This device has been deployed 9 times to date, with a normal deployment schedule of once per month. The initial analysis of the FASC data has given absolute calibration results within 5% of the prelaunch integrating sphere calibrations and a range of variation of 2% between dates. The Partial Aperture Solar Calibrator (PASC), is a set of auxiliary optics that allows the ETM+ to view the sun through a reduced aperture. Data have normally been acquired on a daily basis with the PASC. Initial results with the PASC were encouraging, despite some unexpected saturation in the shortest wavelength band. The response of the ETM+ short wavelength (silicon) bands to the PASC increased initially and has begun to decrease in some of these bands. The longer wavelength (InSb) bands have shown up to 30% oscillations that vary between detectors within the band. Studies are ongoing to better characterize the response to the PASC. The ETM+ also incorporates an internal calibrator (IC), a shutter that oscillates in front of the focal plane that directs light from the internal calibrator lamps to the focal plane. The responses to this device are also varying, though differently than the PASC results. Both the IC and PASC results are attributable to the calibration devices as opposed to the ETM+ itself.

  6. Wafer-level radiometric performance testing of uncooled microbolometer arrays

    NASA Astrophysics Data System (ADS)

    Dufour, Denis G.; Topart, Patrice; Tremblay, Bruno; Julien, Christian; Martin, Louis; Vachon, Carl

    2014-03-01

    A turn-key semi-automated test system was constructed to perform on-wafer testing of microbolometer arrays. The system allows for testing of several performance characteristics of ROIC-fabricated microbolometer arrays including NETD, SiTF, ROIC functionality, noise and matrix operability, both before and after microbolometer fabrication. The system accepts wafers up to 8 inches in diameter and performs automated wafer die mapping using a microscope camera. Once wafer mapping is completed, a custom-designed quick insertion 8-12 μm AR-coated Germanium viewport is placed and the chamber is pumped down to below 10-5 Torr, allowing for the evaluation of package-level focal plane array (FPA) performance. The probe card is electrically connected to an INO IRXCAM camera core, a versatile system that can be adapted to many types of ROICs using custom-built interface printed circuit boards (PCBs). We currently have the capability for testing 384x288, 35 μm pixel size and 160x120, 52 μm pixel size FPAs. For accurate NETD measurements, the system is designed to provide an F/1 view of two rail-mounted blackbodies seen through the Germanium window by the die under test. A master control computer automates the alignment of the probe card to the dies, the positioning of the blackbodies, FPA image frame acquisition using IRXCAM, as well as data analysis and storage. Radiometric measurement precision has been validated by packaging dies measured by the automated probing system and re-measuring the SiTF and Noise using INO's pre-existing benchtop system.

  7. Experimental methods of indoor millimeter-wave radiometric imaging for personnel concealed contraband detection

    NASA Astrophysics Data System (ADS)

    Hu, Taiyang; Xiao, Zelong; Li, Hao; Lv, Rongchuan; Lu, Xuan

    2014-11-01

    The increasingly emerging terrorism attacks and violence crimes around the world have posed severe threats to public security, so carrying out relevant research on advanced experimental methods of personnel concealed contraband detection is crucial and meaningful. All of the advantages of imaging covertly, avoidance of interference with other systems, intrinsic property of being safe to persons under screening , and the superior ability of imaging through natural or manmade obscurants, have significantly combined to enable millimeter-wave (MMW) radiometric imaging to offer great potential in personnel concealed contraband detection. Based upon the current research status of MMW radiometric imaging and urgent demands of personnel security screening, this paper mainly focuses on the experimental methods of indoor MMW radiometric imaging. The reverse radiation noise resulting from super-heterodyne receivers seriously affects the image experiments carried out at short range, so both the generation mechanism and reducing methods of this noise are investigated. Then, the benefit of sky illumination no longer exists for the indoor radiometric imaging, and this leads to the decrease in radiometric temperature contrast between target and background. In order to enhance the radiometric temperature contrast for improving indoor imaging performance, the noise illumination technique is adopted in the indoor imaging scenario. In addition, the speed and accuracy of concealed contraband detection from acquired MMW radiometric images are usually restricted to the deficiencies in traditional artificial interpretation by security inspectors, thus an automatic recognition and location algorithm by integrating improved Fuzzy C-means clustering with moment invariants is put forward. A series of original results are also presented to demonstrate the significance and validity of these methods.

  8. Improved Thermal-Vacuum Compatible Flat Plate Radiometric Souce for System-Level Testing of Optical Sensors

    NASA Technical Reports Server (NTRS)

    Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.

    2015-01-01

    This work describes the development of an improved vacuum compatible flat plate radiometric source used for characterizing and calibrating remote optical sensors, in situ, throughout their testing period. The original flat plate radiometric source was developed for use by the VIIRS instrument during the NPOESS Preparatory Project (NPP). Following this effort, the FPI has had significant upgrades in order to improve both the radiometric throughput and uniformity. Results of the VIIRS testing with the reconfigured FPI are reported and discussed.

  9. Radiometric calibration and noise estimation of acousto-optic tunable filter hyperspectral imaging systems.

    PubMed

    Katrašnik, Jaka; Pernuš, Franjo; Likar, Boštjan

    2013-05-20

    The accuracy of the radiometric response of acousto-optic tunable filter (AOTF) hyperspectral imaging systems is crucial for obtaining reliable measurements. It is therefore important to know the radiometric response and noise characteristics of the hyperspectral imaging system used. A radiometric model of an AOTF hyperspectral imaging system composed of an imaging sensor radiometric model (CCD, CMOS, and sCMOS) and an AOTF light transmission model is proposed. Using the radiometric model, a method for obtaining the fixed pattern noise (FPN) of the imaging system by displacing and imaging an illuminated reference target is developed. Methods for estimating the temporal noise of the imaging system, using the photon transfer method, and for correcting FPN are also presented. Noise estimation and image restoration methods were tested on an AOTF hyperspectral imaging system. The results indicate that the developed methods can accurately calculate temporal and FPN, and can effectively correct the acquired images. After correction, the signal-to-noise ratio of the acquired images was shown to increase by 26%. PMID:23736239

  10. The Eurosdr Project "RADIOMETRIC Aspects of Digital Photogrammetric IMAGES" - Results of the Empirical Phase

    NASA Astrophysics Data System (ADS)

    Honkavaara, E.; Arbiol, R.; Markelin, L.; Martínez, L.; Bovet, S.; Bredif, M.; Chandelier, L.; Heikkinen, V.; Korpela, I.; Lelegard, L.; Pérez, F.; Schläpfer, D.; Tokola, T.

    2011-09-01

    This article presents the empirical research carried out in the context of the multi-site EuroSDR project "Radiometric aspects of digital photogrammetric images" and provides highlights of the results. The investigations have considered the vicarious radiometric and spatial resolution validation and calibration of the sensor system, radiometric processing of the image blocks either by performing relative radiometric block equalization or into absolutely reflectance calibrated products, and finally aspects of practical applications on NDVI layer generation and tree species classification. The data sets were provided by Leica Geosystems ADS40 and Intergraph DMC and the participants represented stakeholders in National Mapping Authorities, software development and research. The investigations proved the stability and quality of evaluated imaging systems with respect to radiometry and optical system. The first new-generation methods for reflectance calibration and equalization of photogrammetric image block data provided promising accuracy and were also functional from the productivity and usability points of view. The reflectance calibration methods provided up to 5% accuracy without any ground reference. Application oriented results indicated that automatic interpretation methods will benefit from the optimal use of radiometrically accurate multi-view photogrammetric imagery.

  11. (abstract) Deep Space Network Radiometric Remote Sensing Program

    NASA Technical Reports Server (NTRS)

    Walter, Steven J.

    1994-01-01

    Planetary spacecraft are viewed through a troposphere that absorbs and delays radio signals propagating through it. Tropospheric water, in the form of vapor, cloud liquid,and precipitation , emits radio noise which limits satellite telemetry communication link performance. Even at X-band, rain storms have severely affected several satellite experiments including a planetary encounter. The problem will worsen with DSN implementation of Ka-band becausecommunication link budgets will be dominated by tropospheric conditions. Troposphere-induced propagation delays currently limit VLBI accuracy and are significant sources of error for Doppler tracking. Additionally, the success of radio science programs such as satellite gravity wave experiments and atmospheric occultation experiments depends on minimizing the effect of watervapor-induced prop agation delays. In order to overcome limitations imposed by the troposphere, the Deep Space Network has supported a program of radiometric remote sensing. Currently, water vapor radiometers (WVRs) and microwave temperature profilers (MTPs) support many aspects of the Deep Space Network operations and research and development programs. Their capability to sense atmospheric water, microwave sky brightness, and atmospheric temperature is critical to development of Ka-band telemetry systems, communication link models, VLBI, satellite gravity waveexperiments, and r adio science missions. During 1993, WVRs provided data for propagation mode development, supp orted planetary missions, and demonstrated advanced tracking capability. Collection of atmospheric statistics is necessary to model and predict performance of Ka-band telemetry links, antenna arrays, and radio science experiments. Since the spectrum of weather variations has power at very long time scales, atmospheric measurements have been requested for periods ranging from one year to a decade at each DSN site. The resulting database would provide reliable statistics on daily

  12. Geometric and radiometric characterization of LANDSAT-D thematic mapper and multispectral scanner data

    NASA Technical Reports Server (NTRS)

    Kieffer, H. H. (Principal Investigator)

    1983-01-01

    A geometrically raw image of Washington, D.C. was acquired and radiometrically corrected. The data show little of the detector stripping common in earlier MSS images. The radiometrically corrected data have uniform means and standard deviations for the detectors in each band; however, the data for different detectors utilize a different pattern of DN levels, resulting in ubiquitous stripping of 1 DN amplitude. Band-to-band registration was assessed using color composites and small area correlation techniques. The spectral equivalency of the first four bands of the thematic mapper with the four bands of the MSS is being examined. Geometric analysis of the Washington, D.C. scene have started and a generalized routine for examining the contents of the label files and nonvideo data files was implemented. Several discrepancies from the documentation are described. Night scenes and daytime ocean scenes required for radiometric purposes were identified and the data ordered.

  13. Artifact correction and absolute radiometric calibration techniques employed in the Landsat 7 image assessment system

    USGS Publications Warehouse

    Boncyk, Wayne C.; Markham, Brian L.; Barker, John L.; Helder, Dennis

    1996-01-01

    The Landsat-7 Image Assessment System (IAS), part of the Landsat-7 Ground System, will calibrate and evaluate the radiometric and geometric performance of the Enhanced Thematic Mapper Plus (ETM +) instrument. The IAS incorporates new instrument radiometric artifact correction and absolute radiometric calibration techniques which overcome some limitations to calibration accuracy inherent in historical calibration methods. Knowledge of ETM + instrument characteristics gleaned from analysis of archival Thematic Mapper in-flight data and from ETM + prelaunch tests allow the determination and quantification of the sources of instrument artifacts. This a priori knowledge will be utilized in IAS algorithms designed to minimize the effects of the noise sources before calibration, in both ETM + image and calibration data.

  14. Absolute radiometric calibration of Als intensity data: effects on accuracy and target classification.

    PubMed

    Kaasalainen, Sanna; Pyysalo, Ulla; Krooks, Anssi; Vain, Ants; Kukko, Antero; Hyyppä, Juha; Kaasalainen, Mikko

    2011-01-01

    Radiometric calibration of airborne laser scanning (ALS) intensity data aims at retrieving a value related to the target scattering properties, which is independent on the instrument or flight parameters. The aim of a calibration procedure is also to be able to compare results from different flights and instruments, but practical applications are sparsely available, and the performance of calibration methods for this purpose needs to be further assessed. We have studied the radiometric calibration with data from three separate flights and two different instruments using external calibration targets. We find that the intensity data from different flights and instruments can be compared to each other only after a radiometric calibration process using separate calibration targets carefully selected for each flight. The calibration is also necessary for target classification purposes, such as separating vegetation from sand using intensity data from different flights. The classification results are meaningful only for calibrated intensity data. PMID:22346660

  15. Radiometric calibration and processing procedure for reflective bands on LANDSAT-4 protoflight Thematic Mapper

    NASA Technical Reports Server (NTRS)

    Barker, J. L.; Abrams, R. B.; Ball, D. L.; Leung, K. C.

    1984-01-01

    The radiometric subsystem of NASA's LANDSAT-4 Thematic Mapper (TM) sensor is described. Special emphasis is placed on the internal calibrator (IC) pulse shapes and timing cycle. The procedures for the absolute radiometric calibration of the TM channels with a 122-centimeter integrating sphere and the transfer of radiometric calibration from the channels to the IC are reviewed. The use of the IC to calibrate TM data in the ground processing system consists of pulse integration, pulse averaging, IC state identification, linear regression analysis, and histogram equalization. An overview of the SCROUNGE-era (before August 1983) method is presented. Procedural differences between SCROUNGE and the TIPS-era (after July 1983) and the implications of these differences are discussed.

  16. Radiometric Calibration of Mars HiRISE High Resolution Imagery Based on Fpga

    NASA Astrophysics Data System (ADS)

    Hou, Yifan; Geng, Xun; Xing, Shuai; Tang, Yonghe; Xu, Qing

    2016-06-01

    Due to the large data amount of HiRISE imagery, traditional radiometric calibration method is not able to meet the fast processing requirements. To solve this problem, a radiometric calibration system of HiRISE imagery based on field program gate array (FPGA) is designed. The montage gap between two channels caused by gray inconsistency is removed through histogram matching. The calibration system is composed of FPGA and DSP, which makes full use of the parallel processing ability of FPGA and fast computation as well as flexible control characteristic of DSP. Experimental results show that the designed system consumes less hardware resources and the real-time processing ability of radiometric calibration of HiRISE imagery is improved.

  17. Preparation of a new autonomous instrumented radiometric calibration site: Gobabeb, Namib Desert

    NASA Astrophysics Data System (ADS)

    Greenwell, Claire; Bialek, Agnieszka; Marks, Amelia; Woolliams, Emma; Berthelot, Béatrice; Meygret, Aimé; Marcq, Sébastien; Bouvet, Marc; Fox, Nigel

    2015-10-01

    A new permanently instrumented radiometric calibration site for high/medium resolution imaging satellite sensors is currently under development, focussing on the visible and near infra-red parts of the spectrum. The site will become a European contribution to the Committee on Earth Observation Satellites (CEOS) initiative RadCalNet (Radiometric Calibration Network). The exact location of the permanent monitoring instrumentation will be defined following the initial site characterisation. The new ESA/CNES RadCalNet site will have a robust uncertainty budget and its data fully SI traceable through detailed characterisation and calibration by NPL of the instruments and artefacts to be used on the site. This includes a CIMEL sun photometer (the permanent instrumentation) an ASD FieldSpec spectroradiometer, Gonio Radiometric Spectrometer System (GRASS), and reference reflectance standards.

  18. Absolute Radiometric Calibration of ALS Intensity Data: Effects on Accuracy and Target Classification

    PubMed Central

    Kaasalainen, Sanna; Pyysalo, Ulla; Krooks, Anssi; Vain, Ants; Kukko, Antero; Hyyppä, Juha; Kaasalainen, Mikko

    2011-01-01

    Radiometric calibration of airborne laser scanning (ALS) intensity data aims at retrieving a value related to the target scattering properties, which is independent on the instrument or flight parameters. The aim of a calibration procedure is also to be able to compare results from different flights and instruments, but practical applications are sparsely available, and the performance of calibration methods for this purpose needs to be further assessed. We have studied the radiometric calibration with data from three separate flights and two different instruments using external calibration targets. We find that the intensity data from different flights and instruments can be compared to each other only after a radiometric calibration process using separate calibration targets carefully selected for each flight. The calibration is also necessary for target classification purposes, such as separating vegetation from sand using intensity data from different flights. The classification results are meaningful only for calibrated intensity data. PMID:22346660

  19. NASA IKONOS Multispectral Radiometric Calibration and 3-Year Temporal Stability Assessment

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Carver, David; Holekamp, Kara; Ryan, Robert; Zanoni, Vicki; Thome, Kurtis; Schiller, Stephen; Aaran, David

    2003-01-01

    Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities can place confidence in the imagery they use and can fully understand its properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other system. In addition, the user community has little or no insight into the design and operation of commercial sensors or into the methods involved in generating commercial products. To address this calibration need, the NASA Stennis Space Center (SSC) Earth Science Applications (ESA) Directorate established a commercial satellite imaging radiometric calibration team consisting of three independent groups: NASA, SSC,ESA, the University of Arizona Remote Sensing Group, and South Dacota State University. Each group determined the absolute radiometric calibration coefficients of the Space Imaging IKONOS 4-band, 4 m multispectral product covering the visible through near-infrared spectral region. For a three year period beginning in 2000, each team employed some variant of a reflectance-based vicarious calibration approach, requiring ground-based measurements coincident with IKONOS image acquisitions and radiative transfer calculations. Several study sites throughout the United States were employed that covered nearly the entire dynamic range of the IKONOS sensor. IKONOS at-sensor radiance values were compared to those estimated by each independent group to determine the IKONOS sensor's radiometric accuracy and stability. Over 10 individual vicariously determined at-sensor radiance estimates were used each year. When combined, these estimates provided a high-precision radiometric gain calibration coefficient. No significant calibration offset was observed. The results of this evaluation provide the scientific community with an independent assessment of the IKONOS sensor's absolute calibration and temporal stability over the 3

  20. Enhanced radiometric detection of Mycobacterium paratuberculosis by using filter-concentrated bovine fecal specimens.

    PubMed Central

    Collins, M T; Kenefick, K B; Sockett, D C; Lambrecht, R S; McDonald, J; Jorgensen, J B

    1990-01-01

    A commercial radiometric medium, BACTEC 12B, was modified by addition of mycobactin, egg yolk suspension, and antibiotics (vancomycin, amphotericin B, and nalidixic acid). Decontaminated bovine fecal specimens were filter concentrated by using 3-microns-pore-size, 13-mm-diameter polycarbonate filters, and the entire filter was placed into the radiometric broth. Comparison of the radiometric technique with conventional methods on 603 cattle from 9 Mycobacterium paratuberculosis-infected herds found that of 75 positive specimens, the radiometric technique detected 92% while conventional methods detected 60% (P less than 0.0005). Only 3.9% of radiometric cultures were contaminated. To measure the effect of filter concentration of specimens on the detection rate, 5 cattle with minimal and 5 with moderate ileum histopathology were sampled weekly for 3 weeks. M. paratuberculosis was detected in 33.3% of nonfiltered specimens and 76.7% of filtered specimens (P less than 0.005). Detection rates were directly correlated with the severity of disease, and the advantage of specimen concentration was greatest on fecal specimens from cattle with low-grade infections. Detection times were also correlated with infection severity: 13.4 +/- 5.9 days with smear-positive specimens, 27.9 +/- 8.7 days with feces from cows with typical subclinical infections, and 38.7 +/- 3.8 days with fecal specimens from cows with low-grade infections. Use of a cocktail of vancomycin, amphotericin B, and nalidixic acid for selective suppression of nonmycobacterial contaminants was better than the commercial product PANTA (Becton Dickinson Microbiologic Systems, Towson, Md.) only when specimens contained very low numbers of M. paratuberculosis. Radiometric culture of filter-concentrated specimens generally doubled the number of positive fecal specimens detected over conventional methods, making it a useful tool for diagnosis and control of bovine paratuberculosis. PMID:2254428

  1. Fourth World Radiometric Reference to SI radiometric scale comparison and implications for on-orbit measurements of the total solar irradiance

    NASA Astrophysics Data System (ADS)

    Fehlmann, A.; Kopp, G.; Schmutz, W.; Winkler, R.; Finsterle, W.; Fox, N.

    2012-04-01

    We report the fourth World Radiometric Reference (WRR)-to-SI comparison. At the National Physical Laboratory we compared three transfer pyrheliometer instruments in power mode with the SI radiometric scale. Compared with the three previous comparisons, we improved the experiment by operating the transfer instruments in vacuum. At the Total solar irradiance Radiometer Facility (TRF) located at the Laboratory for Atmospheric and Space Physics (LASP) in Boulder, we repeated the power comparison of one of the transfer instruments. The TRF also allowed the comparison and characterization of this instrument in irradiance mode. Using the WRR comparisons performed in Davos, we find that the WRR is 0.34% higher than the SI scale. Comparing irradiance mode calibrations with power mode calibrations reveals that previous estimates of stray light of PMO6-type radiometers were very low. The instrument calibrated at TRF was integrated in the space experiment PREMOS on the French satellite PICARD and carries the first vacuum irradiance calibration to space.

  2. Evaluation of the radiometric quality of the TM data using clustering and multispectral distance measures

    NASA Technical Reports Server (NTRS)

    Bartolucci, L. A.; Dean, M. E.; Anuta, P. E.

    1983-01-01

    Radiometrically and geometrically corrected TM data from three different geographic locations were examined. Histograms were inspected for each band to determine the dynamic range of the data, the shape of the distributions, and to verify whether empty bins were introduced by the radiometric correction process. The effect of geometric correction on the radiometry of the resampled pixels was determined. The information content between TM and MSS data sets were compared and the TM data were used to map the thermal effluent discharge into a river ecosystem from a nuclear thermal power plant, and application only possible previously only possible through the acquisition of thermal infrared scanner data from aircraft altitudes.

  3. Overview of current technology in MMW radiometric sensors for law enforcement applications

    NASA Astrophysics Data System (ADS)

    Ferris, David D., Jr.; Currie, Nicholas C.

    2000-07-01

    This paper discusses the current state-of-the-art in millimeter-wave radiometric imagers being developed for law enforcement use within the United States. The most prevalent application at present is the detection of concealed weapons (guns, knives, etc.) with a secondary application involving the detection of drugs and explosives. Three main topics will be addressed: the phenomenology of concealed weapon detection at millimeter wavelengths, the promise and short comings of first generation radiometric imagers, and the characteristics of second generation systems currently under development.

  4. An algorithm for the radiometric and atmospheric correction of AVHRR data in the solar reflective channels

    NASA Astrophysics Data System (ADS)

    Teillet, P. M.

    1992-09-01

    Radiometric and atmospheric corrections are formulated with a view to computing vegetation indices such as the Normalized Difference Vegetation Index (NDVI) from surface reflectances rather than the digital signal levels recorded at the sensor. In particular, look-up table (LUT) results from an atmospheric radiative transfer code are used to save time and avoid the complexities of running and maintaining such a code in a production environment. The data flow for radiometric image correction is very similar to commonly used geometric correction data flows. The role of terrain elevation in the atmospheric correction process is discussed and the effect of topography on NDVI is highlighted.

  5. Comparison of diverse methods for the correction of atmospheric effects on LANDSAT and SKYLAB images. [radiometric correction in Brazil

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (Principal Investigator); Camara, G.; Dias, L. A. V.; Mascarenhas, N. D. D.; Desouza, R. C. M.; Pereira, A. E. C.

    1982-01-01

    Earth's atmosphere reduces a sensors ability in currently discriminating targets. Using radiometric correction to reduce the atmospheric effects may improve considerably the performance of an automatic image interpreter. Several methods for radiometric correction from the open literature are compared leading to the development of an atmospheric correction system.

  6. Airborne lidar and radiometric observations of PBL- and low clouds

    NASA Technical Reports Server (NTRS)

    Flamant, P. H.; Valentin, R.; Pelon, J.

    1992-01-01

    lidar and narrowbeam IR radiometer is conducted to study the scale integration problem. A good agreement within less than 100 m relies on spatial uniformity and an optically thick layer. In the presence of holes, a discrepancy is observed. This is illustrated in figure 2, displaying as a function of time (1) the lidar signals; (2) the target temperature (either clouds or sea surface) retreived from a narrowbeam IR radiometer, 17 C is the sea surface temperature on that day; and (3) the visible flux, linked to cloud albedo, measured by a pyranometer. In preparation of ASTEX, down- and up-looking measurements where conducted on stratocumulus clouds over the Atlantic Ocean near Quimper in Brittany. Depending on the flight pattern orientation with respect to the wind, the top and bottom cloud morphologies are different. Preliminary results are given on cloud morphology, cloud top PDFs, optical porosity, fractional cloudiness, and comparison of lidar and radiometric measurements.

  7. Radiometric performance assessment of Suomi NPP VIIRS SWIR Band (2.25 μm)

    NASA Astrophysics Data System (ADS)

    Uprety, Sirish; Cao, Changyong

    2015-09-01

    Suomi NPP VIIRS SWIR band M11 (2.25 μm) has larger radiometric uncertainty compared to the rest of the reflective solar bands. This is due to a number of reasons including prelaunch calibration uncertainties. One of the most commonly used technique to verify the radiometric stability and accuracy of VIIRS is by intercomparing it with other well calibrated radiometers such as MODIS. However one of the limitations of using MODIS is that VIIRS band M11 RSR doesn't overlap with MODIS bands at all. Thus the accuracy of intercomparison relies completely on how well the spectral differences are analyzed over the given target. Since desert sites have higher reflectance and more flat spectra, this study uses desert sites to analyze M11 radiometric performance. In order to better match the RSR between instruments, we have chosen Landsat 8 OLI SWIR band 2 (2.20 μm) to perform intercomparison. This is mainly because OLI SWIR band 2 fully covers the VIIRS band M11 even though OLI has much wider RSR compared to VIIRS. The study suggests that there exists large radiometric inconsistency between VIIRS M11 and OLI, on the order of 5%. The impact due to spectral differences is estimated and accounted for using EO-1 Hyperion observations and MODTRAN.

  8. Texture analysis of radiometric signatures of new sea ice forming in Arctic leads

    NASA Technical Reports Server (NTRS)

    Eppler, Duane T.; Farmer, L. Dennis

    1991-01-01

    Analysis of 33.6-GHz, high-resolution, passive microwave images suggests that new sea ice accumulating in open leads is characterized by a unique textural signature which can be used to discriminate new ice forming in this environment from adjacent surfaces of similar radiometric temperature. Ten training areas were selected from the data set, three of which consisted entirely of first-year ice, four entirely of multilayer ice, and three of new ice in open leads in the process of freezing. A simple gradient operator was used to characterize the radiometric texture in each training region in terms of the degree to which radiometric gradients are oriented. New ice in leads has a sufficiently high proportion of well-oriented features to distinguish it uniquely from first-year ice and multiyear ice. The predominance of well-oriented features probably reflects physical processes by which new ice accumulates in open leads. Banded structures, which are evident in aerial photographs of new ice, apparently give rise to the radiometric signature observed, in which the trend of brightness temperature gradients is aligned parallel to lead trends. First-year ice and multiyear ice, which have been subjected to a more random growth and process history, lack this banded structure and therefore are characterized by signatures in which well-aligned elements are less dominant.

  9. Spectral and radiometric calibration of the Airborne Visible/Infrared Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Vane, Gregg; Chrien, Thomas G.; Miller, Edward A.; Reimer, John H.

    1987-01-01

    The laboratory spectral and radiometric calibration of the AVIRIS science data collected since 1987 is described. The instrumentation and procedures used in the calibration are discussed and the accuracy achieved in the laboratory as determined by measurement and calculation is compared with the requirements. Instrument performance factors affecting radiometry are described. The paper concludes with a discussion of future plans.

  10. Lifetime radiometric calibration of HJ-1A/B CCD sensor using Dunhuang Gobi site

    NASA Astrophysics Data System (ADS)

    Han, Qijin; Zhang, Xuewen; Liu, Li; Wang, Aichun

    2014-11-01

    Dunhuang Gobi site, a pseudo-invariant ground target, has been extensively used to calibrate the remote sensing instruments because of its high spatial and spectral uniformity and good temporal stability. Four Charge Coupled Device (CCD) sensors onboard HUANGJING-A/B (HJ-1A/B) satellites have been running 5-years since launched in 2008, and provided important remote sensing data for land surface reflectance retrieval, bio/geophysical variables estimation and environment pollution /disaster monitoring. The radiometric performance of HJ-1A/B CCD may change after launched because of many factors, thus, we have carried out many ground measurement campaigns at a pseudo-invariant test site-Dunhuang gobi to perform radiometric calibration of these sensors. This article describes the characteristics of Dunhuang gobi site and lifetime radiometric calibration monitoring results obtained for four CCD sensors. The results indicate that the long-term changes in calibration coefficients trending exceeding the dark-noise changes are primarily due to the drifts in the CCD radiometric responsivity, and the degradations of HJ-1A/B CCD are from -2.3%/year to -9.5%/year.

  11. ESTIMATING SUBPIXEL SURFACE TEMPERATURES AND ENERGY FLUXES FROM THE VEGETATION INDEX-RADIOMETRIC TEMPERATURE RELATIONSHIP

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Routine (i.e., daily to weekly) monitoring of surface energy fluxes, particularly evapotranspiration (ET), using satellite observations of radiometric surface temperature has not been feasible at high pixel resolution because of the low frequency in satellite coverage over the region of interest (i...

  12. MODIS Cloud Optical Property Retrieval Uncertainties Derived from Pixel-Level VNIR/SWIR Radiometric Uncertainties

    NASA Technical Reports Server (NTRS)

    Platnick, S.; Wind, G.; Xiong, X.

    2011-01-01

    Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals of optical thickness and effective particle radius for liquid water and ice phase clouds employ a well-known VNIR/ SWIR solar reflectance technique. For this type of algorithm, we evaluate the quantitative uncertainty in simultaneous retrievals of these two cloud parameters to pixel-level radiometric calibration estimates and other fundamental (and tractable) error sources.

  13. Adjustments to the MODIS Terra Radiometric Calibration and Polarization Sensitivity in the 2010 Reprocessing

    NASA Technical Reports Server (NTRS)

    Meister, Gerhard; Franz, Bryan A.

    2011-01-01

    The Moderate-Resolution Imaging Spectroradiometer (MODIS) on NASA s Earth Observing System (EOS) satellite Terra provides global coverage of top-of-atmosphere (TOA) radiances that have been successfully used for terrestrial and atmospheric research. The MODIS Terra ocean color products, however, have been compromised by an inadequate radiometric calibration at the short wavelengths. The Ocean Biology Processing Group (OBPG) at NASA has derived radiometric corrections using ocean color products from the SeaWiFS sensor as truth fields. In the R2010.0 reprocessing, these corrections have been applied to the whole mission life span of 10 years. This paper presents the corrections to the radiometric gains and to the instrument polarization sensitivity, demonstrates the improvement to the Terra ocean color products, and discusses issues that need further investigation. Although the global averages of MODIS Terra ocean color products are now in excellent agreement with those of SeaWiFS and MODIS Aqua, and image quality has been significantly improved, the large corrections applied to the radiometric calibration and polarization sensitivity require additional caution when using the data.

  14. MODIS Cloud Optical Property Retrieval Uncertainties Derived from Pixel-Level Radiometric Error Estimates

    NASA Technical Reports Server (NTRS)

    Platnick, Steven; Wind, Galina; Xiong, Xiaoxiong

    2011-01-01

    MODIS retrievals of cloud optical thickness and effective particle radius employ a well-known VNIR/SWIR solar reflectance technique. For this type of algorithm, we evaluate the uncertainty in simultaneous retrievals of these two parameters to pixel-level (scene-dependent) radiometric error estimates as well as other tractable error sources.

  15. Initial Radiometric Calibration of the AWiFS Using Vicarious Calibration Techniques

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary

    2007-01-01

    The NASA team of University of Arizona, South Dakota State University, and NASA SSC produce consistent results. The AWiFS calibration coefficients agree reasonably well with the NASA team estimate. The NASA team will continue to assess AWiFS radiometric accuracy.

  16. Landsat-8 Operational Land Imager (OLI) radiometric performance on-orbit

    USGS Publications Warehouse

    Morfitt, Ron; Barsi, Julia A.; Levy, Raviv; Markham, Brian L.; Micijevic, Esad; Ong, Lawrence; Scaramuzza, Pat; Vanderwerff, Kelly

    2015-01-01

    Expectations of the Operational Land Imager (OLI) radiometric performance onboard Landsat-8 have been met or exceeded. The calibration activities that occurred prior to launch provided calibration parameters that enabled ground processing to produce imagery that met most requirements when data were transmitted to the ground. Since launch, calibration updates have improved the image quality even more, so that all requirements are met. These updates range from detector gain coefficients to reduce striping and banding to alignment parameters to improve the geometric accuracy. This paper concentrates on the on-orbit radiometric performance of the OLI, excepting the radiometric calibration performance. Topics discussed in this paper include: signal-to-noise ratios that are an order of magnitude higher than previous Landsat missions; radiometric uniformity that shows little residual banding and striping, and continues to improve; a dynamic range that limits saturation to extremely high radiance levels; extremely stable detectors; slight nonlinearity that is corrected in ground processing; detectors that are stable and 100% operable; and few image artifacts.

  17. Investigation of Pre- and Post-Flight Radiometric Calibration Uncertainties from Surface Based Measurements

    SciTech Connect

    Heath, D.F.; Wei, Z.Y.; Ahman, Z.

    1997-06-01

    A new technique has been developed for inferring column ozone amounts and aerosol optical depths from zenith sky observations. A new radiometric calibration technique for large aperture remote sensing instruments observing the earth through space has been validated which subsequently increased the accuracy of remote sensing measurements of ozone and vertical profiles using measurements of back-scattered ultraviolet solar radiation.

  18. Radiometric modelling of a space optical instrument: an example of application to PHEBUS

    NASA Astrophysics Data System (ADS)

    Corso, Alain J.; Zuppella, Paola; Mariscal, Jean Francois; Rouanet, Nicolas; Quémerais, Eric; Nardello, Marco; Nicolosi, Piergiorgio; Tessarolo, Enrico; Bacco, Davide; Gerlin, Francesca; Zuccon, Sara; Pelizzo, Maria G.

    2015-05-01

    Probing of Hermean Exosphere By Ultraviolet Spectroscopy (PHEBUS) is a dual channels spectrometer working in the Extreme UltraViolet (EUV) and Far UltraViolet (FUV) range. It will be on board of ESA BepiColombo cornerstone mission and it will be devoted to investigate the composition, the dynamic, the formation and the feeding mechanisms of Mercury's exosphere system. A consistent interpretation of the observational data collected by PHEBUS requires a deeply knowledge of its radiometric behavior. The Mueller's matrix formalism can be adopted to derive an accurate radiometric model able to takes into account also the polarization state of the source observed by PHEBUS. Moreover, this theoretical model can be further verified and refined during an experimental ground calibration campaign. In this work we present the radiometric model derived for PHEBUS spectrometer together with some results obtained during the Flight Model (FM) ground calibration which is still ongoing. In particular, the obtained results employing this approach show that this is a complete and versatile method to perform the radiometric calibration of a generic space instrument.

  19. Serum bactericidal test.

    PubMed Central

    Stratton, C W

    1988-01-01

    The serum bactericidal test represents one of the few in vitro tests performed in the clinical microbiology laboratory that combines the interaction of the pathogen, the antimicrobial agent, and the patient. Although the use of such a test antedates the antimicrobial era, its performance, results, and interpretation have been subject to question and controversy. Much of the confusion concerning the serum bactericidal test can be avoided by an understanding of the various factors which influence bactericidal testing. In addition, the methodologic aspects of the serum bactericidal test have recently been addressed and should place this test on firmer ground. New information on the clinical utility of this test is becoming available; additional data are needed to establish more clearly the usefulness of the serum bactericidal test in specific infections. Such clinical trials from multiple centers will enable firmer recommendations for the future use of the serum bactericidal test. PMID:3060242

  20. Enhanced radiometric detection of Mycobacterium paratuberculosis by using filter-concentrated bovine fecal specimens

    SciTech Connect

    Collins, M.T.; Kenefick, K.B.; Sockett, D.C.; Lambrecht, R.S.; McDonald, J.; Jorgensen, J.B. )

    1990-11-01

    A commercial radiometric medium, BACTEC 12B, was modified by addition of mycobactin, egg yolk suspension, and antibiotics (vancomycin, amphotericin B, and nalidixic acid). Decontaminated bovine fecal specimens were filter concentrated by using 3-microns-pore-size, 13-mm-diameter polycarbonate filters, and the entire filter was placed into the radiometric broth. Comparison of the radiometric technique with conventional methods on 603 cattle from 9 Mycobacterium paratuberculosis-infected herds found that of 75 positive specimens, the radiometric technique detected 92% while conventional methods detected 60% (P less than 0.0005). Only 3.9% of radiometric cultures were contaminated. To measure the effect of filter concentration of specimens on the detection rate, 5 cattle with minimal and 5 with moderate ileum histopathology were sampled weekly for 3 weeks. M. paratuberculosis was detected in 33.3% of nonfiltered specimens and 76.7% of filtered specimens (P less than 0.005). Detection rates were directly correlated with the severity of disease, and the advantage of specimen concentration was greatest on fecal specimens from cattle with low-grade infections. Detection times were also correlated with infection severity: 13.4 +/- 5.9 days with smear-positive specimens, 27.9 +/- 8.7 days with feces from cows with typical subclinical infections, and 38.7 +/- 3.8 days with fecal specimens from cows with low-grade infections. Use of a cocktail of vancomycin, amphotericin B, and nalidixic acid for selective suppression of nonmycobacterial contaminants was better than the commercial product PANTA (Becton Dickinson Microbiologic Systems, Towson, Md.) only when specimens contained very low numbers of M. paratuberculosis.

  1. Dynamic noise corrected hyperspectral radiometric calibration in the SWIR range using a supercontinuum laser

    NASA Astrophysics Data System (ADS)

    Keresztes, Janos C.; Aernouts, Ben; Koshel, R. J.; Saeys, Wouter

    2015-09-01

    As line scanning short wave infrared (SWIR) hyperspectral imaging (HSI) is a growing field in the food industry, it is important to select efficient illumination designs to image contaminants with high contrast and low noise. Illumination systems can efficiently be compared and optimized through the use of ray tracing simulations. However, these simulations provide illumination patterns in absolute radiometric units while HSI systems typically provide relative measurements. To bridge this gap, a supercontinuum laser and monochromator setup was used in this study to calibrate a SWIR HSI imager in spectral radiometric units. For the radiometric calibration, an integrating sphere (IS) was illuminated with the monochromatic laser light, while both a high sensitivity photodiode and the hyperspectral camera were positioned at different ports of the IS to measure the diffuse light synchronously. For each spectral band, the radiance observed by the imager corresponding to a line was detected using image analysis, while the remainder of the image was used to sample the noise of the sensor. Laser power fluctuations were monitored using a power meter coupled with a thermal sensor, allowing for their correction. As these measurements were time consuming, while InGaAs based sensors are very sensitive to thermal drift, the dark current was sampled frequently to avoid noise time drifts. This approach allowed correcting for 6% of temporal noise fluctuations. A per-pixel linear radiometric model was fitted with an R2 of 0:94+/-0:3 and used to transfer the measured light distribution of a halogen spot with and without a diffuser into absolute radiometric units. This allowed comparing measurements with the results of ray tracing.

  2. Analyzing Spectral Characteristics of Shadow Area from ADS-40 High Radiometric Resolution Aerial Images

    NASA Astrophysics Data System (ADS)

    Hsieh, Yi-Ta; Wu, Shou-Tsung; Chen, Chaur-Tzuhn; Chen, Jan-Chang

    2016-06-01

    The shadows in optical remote sensing images are regarded as image nuisances in numerous applications. The classification and interpretation of shadow area in a remote sensing image are a challenge, because of the reduction or total loss of spectral information in those areas. In recent years, airborne multispectral aerial image devices have been developed 12-bit or higher radiometric resolution data, including Leica ADS-40, Intergraph DMC. The increased radiometric resolution of digital imagery provides more radiometric details of potential use in classification or interpretation of land cover of shadow areas. Therefore, the objectives of this study are to analyze the spectral properties of the land cover in the shadow areas by ADS-40 high radiometric resolution aerial images, and to investigate the spectral and vegetation index differences between the various shadow and non-shadow land covers. According to research findings of spectral analysis of ADS-40 image: (i) The DN values in shadow area are much lower than in nonshadow area; (ii) DN values received from shadowed areas that will also be affected by different land cover, and it shows the possibility of land cover property retrieval as in nonshadow area; (iii) The DN values received from shadowed regions decrease in the visible band from short to long wavelengths due to scattering; (iv) The shadow area NIR of vegetation category also shows a strong reflection; (v) Generally, vegetation indexes (NDVI) still have utility to classify the vegetation and non-vegetation in shadow area. The spectral data of high radiometric resolution images (ADS-40) is potential for the extract land cover information of shadow areas.

  3. Rapid radiometric methods to detect and differentiate Mycobacterium tuberculosis/M. bovis from other mycobacterial species

    SciTech Connect

    Siddiqi, S.H.; Hwangbo, C.C.; Silcox, V.; Good, R.C.; Snider, D.E. Jr.; Middlebrook, G.

    1984-10-01

    Rapid methods for the differentiation of Mycobacterium tuberculosis/M. bovis (TB complex) from other mycobacteria (MOTT bacilli) were developed and evaluated in a three-phase study. In the first phase, techniques for identification of Mycobacterium species were developed by using radiometric technology and BACTEC Middlebrook 7H12 liquid medium. Based on /sup 14/CO/sub 2/ evolution, characteristic growth patterns were established for 13 commonly encountered mycobacterial species. Mycobacteria belonging to the TB complex were differentiated from other mycobacteria by cellular morphology and rate of /sup 14/CO/sub 2/ evolution. For further differentiation, radiometric tests for niacin production and inhibition by Q-nitro-alpha-acetyl amino-beta-hydroxy-propiophenone (NAP) were developed. In the second phase, 100 coded specimens on Lowenstein-Jensen medium were identified as members of the TB complex, MOTT bacilli, bacteria other than mycobacteria, or ''no viable organisms'' within 3 to 12 (average 6.4) days of receipt from the Centers for Disease Control. Isolation and identification of mycobacteria from 20 simulated sputum specimens were carried out in phase III. Out of 20 sputum specimens, 16 contained culturable mycobacteria, and all of the positives were detected by the BACTEC method in an average of 7.3 days. The positive mycobacterial cultures were isolated and identified as TB complex or MOTT bacilli in an average of 12.8 days. The radiometric NAP test was found to be highly sensitive and specific for a rapid identification of TB complex, whereas the radiometric niacin test was found to have some inherent problems. Radiometric BACTEC and conventional methodologies were in complete agreement in Phase II as well as in Phase III.

  4. Using the Dunhuang test site to monitor the radiometric stability of the ZY-3 multispectral sensor

    NASA Astrophysics Data System (ADS)

    Zhang, Xuewen; Han, Qijin; Liu, Li

    2014-11-01

    The ZY-3 satellite plays an important role in agriculture, forestry, water conservancy, ecological environment, and so on since its successfully running. In order to achieve continuity, stability and reliability of the remote sensing data, and improve quantitative application level of the ZY-3 satellite data, an accurate sensor radiometric calibration is essential. Because ZY-3 satellite doesn't have onboard calibration system, in-fight filed absolute radiometric calibration as a means to effective monitor the radiometric stability.This paper uses multi-day, multi-field at the Dunhuang test site to calibrate the ZY-3 multispectral sensor. The experiment obtained a synchronization measurement data on the August 18, 23 and 28, respectively. The two of ground surface were selected for measuring reflectance, which middling reflectance field (20%) and high reflectance field (40%). At the time of the ZY-3 overpass on the site, synchronous measure surface reflectance of ground targets, atmospheric optical characteristics parameters, such as atmospheric aerosol optical depth, atmospheric columnar water vapor content. Then use the radiative transfer model to estimate the top of atmosphere (TOA) radiance for MSS band. Radiometric calibration coefficient of MSS band was estimated by comparing the TOA radiance with average digital number of the MSS image. Based on multi-day, multi-field, and the real-time measurement at the Dunhuang site, radiometric calibration for ZY-3 MSS was successfully performed using reflectance-based method and calibration coefficients for MSS bands were obtained as well. According to contrast between in-fight calibration and the prelaunch, it was shown that the response of MSS changed at some extent after launch, especially band 1 and band 4. As a result, it was quite essential to update calibration coefficient timely and periodically in order to monitor the change of ZY-3 MSS better and to improve the quantitative application of MSS data as well.

  5. A linear approach for radiometric calibration of full-waveform Lidar data

    NASA Astrophysics Data System (ADS)

    Roncat, Andreas; Pfeifer, Norbert; Briese, Christian

    2012-11-01

    During the past decade, small-footprint full-waveform lidar systems have become increasingly available, especially airborne. The primary output of these systems is high-resolution topographic information in the form of three-dimensional point clouds over large areas. Recording the temporal profile of the transmitted laser pulse and of its echoes enables to detect more echoes per pulse than in the case of discrete-return lidar systems, resulting in a higher point density over complex terrain. Furthermore, full-waveform instruments also allow for retrieving radiometric information of the scanned surfaces, commonly as an amplitude value and an echo width stored together with the 3D coordinates of the single points. However, the radiometric information needs to be calibrated in order to merge datasets acquired at different altitudes and/or with different instruments, so that the radiometric information becomes an object property independent of the flight mission and instrument parameters. State-of-the-art radiometric calibration techniques for full-waveform lidar data are based on Gaussian Decomposition to overcome the ill-posedness of the inherent inversion problem, i.e. deconvolution. However, these approaches make strong assumptions on the temporal profile of the transmitted laser pulse and the physical properties of the scanned surfaces, represented by the differential backscatter cross-section. In this paper, we present a novel approach for radiometric calibration using uniform B-splines. This kind of functions allows for linear inversion without constraining the temporal shape of the modeled signals. The theoretical derivation is illustrated by examples recorded with a Riegl LMS-Q560 and an Optech ALTM 3100 system, respectively.

  6. Serum free hemoglobin test

    MedlinePlus

    Blood hemoglobin; Serum hemoglobin ... Hemoglobin (Hb) is the main component of red blood cells. It is a protein that carries oxygen. ... people may contain up to 5 mg/dL hemoglobin. Normal value ranges may vary slightly among different ...

  7. Serum globulin electrophoresis

    MedlinePlus

    ... may indicate: Acute infection Bone marrow cancer called multiple myeloma Chronic inflammatory disease (for example, rheumatoid arthritis and ... test Hemoglobin Hyperimmunization Immunoelectrophoresis - ... electrophoresis - serum Rheumatoid arthritis Systemic lupus erythematosus ...

  8. Applicability of the product isolation and the radiometric aromatase assays for the measurement of low levels of aromatase: lack of aromatase activity in the human endometrium.

    PubMed

    Prefontaine, M; Shih, C; Pan, C C; Bhavnani, B R

    1990-12-01

    The purpose of this investigation was to assess the applicability of two well established procedures: (i) the product isolation assay and (ii) the radiometric 3H2O assay for the determination of very low levels of aromatase activity. The methods were validated and used to assess the capacity of normal and neoplastic human endometrium to synthesize oestrogens from androgens. Using the product isolation assay, various specimens (n = 27) of normal and neoplastic endometrium were incubated with [1,2,6,7-3H]testosterone either by a standard incubation procedure or by a superfusion technique. Following the incubation, carrier oestrone and oestradiol or [14C]oestrone and [14C]oestradiol were added, and the oestrogens were isolated and purified by paper chromatography and high-performance liquid chromatography. The radiochemical purity of oestrone and oestradiol was checked by the isotope dilution technique. In all samples, the 3H associated with oestrone and oestradiol failed to recrystallize as oestrone and oestradiol. No radioactivity was detectable in the oestrone and oestradiol crystals after acetylation. Similarly, 16 endometrial samples were tested for aromatase activity by the 3H2O release assay using [1 beta-3H]androstenedione as substrate. The results indicate that 3H2O was indeed released during these incubations, but this activity could not be inhibited by the aromatase inhibitor 4-hydroxyandrostenedione, by excess substrate or by heat inactivation of the tissue. Furthermore, the release of 3H2O from [1 beta-3H]androstenedione under the incubation conditions used (Dulbecco's modified Eagle's medium or RPMI-1640 containing fetal bovine serum and NADPH) also occurred in the absence of any tissue. This activity was not inhibited by 4-hydroxyandrostenedione nor by excess substrate. The results demonstrate that the human endometrium does not contain detectable levels of aromatase activity and that the radiometric assay can give rise to false-positive results if used

  9. Improved Thermal-Vacuum Compatible Flat Plate Radiometric Source For System-Level Testing Of Optical Sensors

    NASA Technical Reports Server (NTRS)

    Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.

    2016-01-01

    In this work, we describe an improved thermal-vacuum compatible flat plate radiometric source which has been developed and utilized for the characterization and calibration of remote optical sensors. This source is unique in that it can be used in situ, in both ambient and thermal-vacuum environments, allowing it to follow the sensor throughout its testing cycle. The performance of the original flat plate radiometric source was presented at the 2009 SPIE1. Following the original efforts, design upgrades were incorporated into the source to improve both radiometric throughput and uniformity. The pre-thermal-vacuum (pre-TVAC) testing results of a spacecraft-level optical sensor with the improved flat plate illumination source, both in ambient and vacuum environments, are presented. We also briefly discuss potential FPI configuration changes in order to improve its radiometric performance.

  10. Improving Ocean Color Data Products using a Purely Empirical Approach: Reducing the Requirement for Radiometric Calibration Accuracy

    NASA Technical Reports Server (NTRS)

    Gregg, Watson

    2008-01-01

    Radiometric calibration is the foundation upon which ocean color remote sensing is built. Quality derived geophysical products, such as chlorophyll, are assumed to be critically dependent upon the quality of the radiometric calibration. Unfortunately, the goals of radiometric calibration are not typically met in global and large-scale regional analyses, and are especially deficient in coastal regions. The consequences of the uncertainty in calibration are very large in terms of global and regional ocean chlorophyll estimates. In fact, stability in global chlorophyll requires calibration uncertainty much greater than the goals, and outside of modern capabilities. Using a purely empirical approach, we show that stable and consistent global chlorophyll values can be achieved over very wide ranges of uncertainty. Furthermore, the approach yields statistically improved comparisons with in situ data, suggesting improved quality. The results suggest that accuracy requirements for radiometric calibration cab be reduced if alternative empirical approaches are used.

  11. An information theory characterization of radar images and a new definition for radiometric resolution

    NASA Technical Reports Server (NTRS)

    Frost, V. S.; Shanmugan, K. S.; Holtzman, J. C.

    1982-01-01

    The noise properties of the radar image formation process are used in the present modeling of a communication channel in which the desired target properties are the information transmitted, and the final image represents the received signal. The average information rate over this communication channel is calculated together with appropriate bounds and approximations, and is found to be small on a per-sample basis. As a result, many samples must be averaged to allow for the discrimination, or classification, of several levels of target reflectivity. These information rate properties are consistent with known results concerning target detection and image quality in speckle, and the rate is applicable to the definition of radar image radiometric resolution. Radiometric resolution is functionally related to the degree of noncoherent averaging performed by the sensor.

  12. Errors in radiometric remote sensing of sea-surface temperature and salinity

    NASA Technical Reports Server (NTRS)

    Britt, C. L., Jr.

    1984-01-01

    Techniques for remote measurement of sea-surface physical temperature and salinity using radiometric measurements from aircraft or satellite are reviewed. Studies have been conducted to determine the sensitivity of the errors in surface temperature and salinity to errors in the measured brightness temperatures using combinations of UHF, L, S, and C-band measurements. These investigations were made using values of conductivity, static dielectric constant, and relaxation time derived from the regression equations of Klein and Swift (1977). Results of the error sensitivity study are presented in the form of error contour plots which permit the calculation of errors in the estimation of the physical parameters for given errors in the raw radiometric measurements.

  13. Bandwidth and spectral stray light effects in the NASA GSFC Radiometric Calibration Facility primary transfer radiometer

    NASA Astrophysics Data System (ADS)

    Barnes, Robert A.; Cooper, John W.; Marketon, John E.; Brown, Steven W.; Johnson, B. Carol; Butler, James J.

    2006-08-01

    As part of an effort to reduce uncertainties in the radiometric calibrations of integrating sphere sources and standard lamp irradiance sources, the Goddard Space Flight Center (GSFC) Radiometric Calibration Facility's (RCF) primary radiometer was characterized at the NIST facility for Spectral Irradiance and Radiance Calibrations with Uniform Sources (SIRCUS). Based on those measurements, a nominal slit scattering function was developed for the radiometer. This allowed calculations of band averaged spectral radiances and irradiances for the radiometer's measurements of sphere and standard lamp sources, respectively. From these calculations the effects of bandwidth and spectral stray light were isolated for measurements in the blue spectral region. These effects, which depend on the spectral distribution of the source being measured, can be as large as 8% for measurements at 400 nm. The characterization results and a correction algorithm for these effects are presented here.

  14. A liquid-helium-cooled absolute reference cold load for long-wavelength radiometric calibration

    NASA Technical Reports Server (NTRS)

    Bensadoun, Marc; Witebsky, Chris; Smoot, George; De Amici, Giovanni; Kogut, AL; Levin, Steve

    1992-01-01

    Design, radiometric and thermal performance, and operation of a large diameter (78 cm) liquid-helium-cooled blackbody absolute reference cold load (CL) for the calibration of microwave radiometers is described. CL provides an absolute calibration near the liquid-helium (LHe) boiling point, with total uncertainty in the radiometric temperature of less than 30 mK over the 2.5-23 cm wavelength operating range. CL was used at several wavelengths at the South Pole, Antarctica and the White Mountain Research Center, California. Results show that, for the instruments operated at 20-, 12-, 7.9-, and 4.0 cm wavelength at the South Pole, the total corrections to the LHe boiling-point temperature (about 3.8 K) were 48 +/-23, 18 +/-10, 10 +/-18, and 15 +/-mK.

  15. Improved ground calibration results from Southwest Research Institute Ultraviolet Radiometric Calibration Facility (UV-RCF)

    NASA Astrophysics Data System (ADS)

    Davis, Michael W.; Greathouse, Thomas K.; Gladstone, G. Randall; Retherford, Kurt D.; Slater, David C.; Stern, S. Alan; Versteeg, Maarten H.

    2014-07-01

    Four compact planetary ultraviolet spectrographs have been built by Southwest Research Institute and successfully operated on different planetary missions. These spectrographs underwent a series of ground radiometric calibrations before delivery to their respective spacecraft. In three of the four cases, the in-flight measured sensitivity was approximately 50% lower than the ground measurement. Recent tests in the Southwest Research Institute Ultraviolet Radiometric Calibration Facility (UV-RCF) explain the discrepancy between ground and flight results. Revised ground calibration results are presented for the Rosetta-Alice, New Horizons-Alice, the Lunar Reconnaissance Orbiter Lyman- Alpha Mapping Project, and Juno-Ultraviolet Spectrograph (UVS) and are then compared to the original ground and flight calibrations. The improved understanding of the calibration system reported here will result in improved ground calibration of the upcoming Jupiter Icy Moons Explorer (JUICE)-UVS.

  16. Mississippi exploration field trials using microbial, radiometrics, free soil gas, and other techniques

    SciTech Connect

    Moody, J.S.; Brown, L.R.; Thieling, S.C.

    1995-12-31

    The Mississippi Office of Geology has conducted field trials using the surface exploration techniques of geomicrobial, radiometrics, and free soil gas. The objective of these trials is to determine if Mississippi oil and gas fields have surface hydrocarbon expression resulting from vertical microseepage migration. Six fields have been surveyed ranging in depth from 3,330 ft to 18,500 ft. The fields differ in trapping styles and hydrocarbon type. The results so far indicate that these fields do have a surface expression and that geomicrobial analysis as well as radiometrics and free soil gas can detect hydrocarbon microseepage from pressurized reservoirs. All three exploration techniques located the reservoirs independent of depth, hydrocarbon type, or trapping style.

  17. Radiometric calibration of frame transfer CCD camera with uniform source system

    NASA Astrophysics Data System (ADS)

    Zhou, Jiankang; Shi, Rongbao; Chen, Yuheng; Zhou, Yuying; Shen, Weimin

    2010-08-01

    This paper presents a radiometric calibration method based on visibility function and uniform source system. The uniform system is mainly comprised of an integrating sphere and a monitoring silicon detector. The current of the silicon detector with a visibility function filter corresponds to the luminance at the exit port of integrating sphere through standard luminance meter transfer. The radiance at the camera entrance pupil is calculated for different solar zenith angles and Earth surface albedos by the MODTRAN atmospheric code. To simplify the calibration process, the radiance at its entrance pupil is integrated by visibility function. The shift smear of the frame transfer CCD is removed by the radiometric calibration and the amending ratio factor is introduced in the retrieving methods. The imaging experiment verifies the reliability of the calibration method and retrieves good quality image.

  18. Radiometric performance results of the New Horizons' ALICE UV imaging spectrograph

    NASA Astrophysics Data System (ADS)

    Slater, David C.; Davis, Michael W.; Olkin, Catherine B.; Scherrer, John; Stern, S. Alan

    2005-09-01

    We describe the radiometric performance and calibration results of the New Horizons' ALICE flight model. This ALICE is a lightweight (4.4 kg), low-power (4.4 W), ultraviolet spectrograph based on the ALICE instrument now in flight aboard the European Space Agency's Rosetta spacecraft. Its primary job will be to detect a variety of important atomic and molecular species in Pluto's atmosphere, and to determine their relative abundances so that a complete picture of Pluto's atmospheric composition can be determined for the first time. ALICE will also be used to search for an atmosphere around Pluto's moon, Charon, as well as the Kuiper Belt Objects (KBOs) New Horizons hopes to fly by after Pluto-Charon. Detailed radiometric performance results of the ALICE flight model are presented and discussed.

  19. Radiometric responsivity determination for Feature Identification and Location Experiment (FILE) flown on space shuttle mission

    NASA Technical Reports Server (NTRS)

    Wilson, R. G.; Davis, R. E.; Wright, R. E., Jr.; Sivertson, W. E., Jr.; Bullock, G. F.

    1986-01-01

    A procedure was developed to obtain the radiometric (radiance) responsivity of the Feature Identification and Local Experiment (FILE) instrument in preparation for its flight on Space Shuttle Mission 41-G (November 1984). This instrument was designed to obtain Earth feature radiance data in spectral bands centered at 0.65 and 0.85 microns, along with corroborative color and color-infrared photographs, and to collect data to evaluate a technique for in-orbit autonomous classification of the Earth's primary features. The calibration process incorporated both solar radiance measurements and radiative transfer model predictions in estimating expected radiance inputs to the FILE on the Shuttle. The measured data are compared with the model predictions, and the differences observed are discussed. Application of the calibration procedure to the FILE over an 18-month period indicated a constant responsivity characteristic. This report documents the calibration procedure and the associated radiometric measurements and predictions that were part of the instrument preparation for flight.

  20. Extreme Ultraviolet Variability Experiment (EVE) Multiple EUV Grating Spectrographs (MEGS): Radiometric Calibrations and Results

    NASA Technical Reports Server (NTRS)

    Hock, R. A.; Woods, T. N.; Crotser, D.; Eparvier, F. G.; Woodraska, D. L.; Chamberlin, P. C.; Woods, E. C.

    2010-01-01

    The NASA Solar Dynamics Observatory (SDO), scheduled for launch in early 2010, incorporates a suite of instruments including the Extreme Ultraviolet Variability Experiment (EVE). EVE has multiple instruments including the Multiple Extreme ultraviolet Grating Spectrographs (MEGS) A, B, and P instruments, the Solar Aspect Monitor (SAM), and the Extreme ultraviolet SpectroPhotometer (ESP). The radiometric calibration of EVE, necessary to convert the instrument counts to physical units, was performed at the National Institute of Standards and Technology (NIST) Synchrotron Ultraviolet Radiation Facility (SURF III) located in Gaithersburg, Maryland. This paper presents the results and derived accuracy of this radiometric calibration for the MEGS A, B, P, and SAM instruments, while the calibration of the ESP instrument is addressed by Didkovsky et al. . In addition, solar measurements that were taken on 14 April 2008, during the NASA 36.240 sounding-rocket flight, are shown for the prototype EVE instruments.

  1. Determination of cloud ice water content and geometrical thickness using microwave and infrared radiometric measurements

    NASA Technical Reports Server (NTRS)

    Wu, Man-Li C.

    1987-01-01

    Cloud ice water content and cloud geometrical thickness have been determined using a combination of near-infrared, thermal infrared and thermal microwave radiometric measurements. The radiometric measurements are from a Multispectral Cloud Radiometer, which has seven channels ranging from visible to thermal infrared, and an Advanced Microwave Moisture Sounder, which has four channels ranging from 90 to 183 GHz. Studies indicate that the microwave brightness temperatures depend not only on the amount of ice water content but also on the vertical distribution of ice water content. Studies also show that the low brightness temperature at 92 GHz for large ice water content is due to cloud reflection which reflects most of the irradiance incident at the cloud base downward. Therefore the 92 GHz channel detects a low brightness temperature at the cloud top.

  2. Results of a thermoluminescence radiometric survey in Takala area of China's Tarim basin

    SciTech Connect

    Siegel, F.R. ); Vaz, J.E. ); Su, J. )

    1993-01-11

    This paper reports on a thermoluminescence dosimeter (TLD) radiometric study of the near-surface radiation flux which was done as an adjunct to oil exploration research in the Takala area, Tarim basin, western China. About 80 sq km of the basin were evaluated using lithium fluoride (LiF) TLDs buried at about 0.5 m; Rn and [Delta]C (anomalous carbonate) measurements were made in this region as well. Small target areas were defined in the region by low value TL radiometric signals. Comparative measurements of Rn and [Delta]C were not as effective as TL in defining small areas for follow-up seismic work or in revealing the structural trends. The structural nature of the area was mimicked by the near-surface radiometries distribution pattern determined by TLDs and suggested the possibility of fault-influenced traps in the subsurface.

  3. Initial on-orbit radiometric calibration of the Suomi NPP VIIRS reflective solar bands

    NASA Astrophysics Data System (ADS)

    Lei, Ning; Wang, Zhipeng; Fulbright, Jon; Lee, Shihyan; McIntire, Jeff; Chiang, Kwofu; Xiong, Xiaoxiong

    2012-09-01

    The on-orbit radiometric response calibration of the VISible/Near InfraRed (VISNIR) and the Short-Wave InfraRed (SWIR) bands of the Visible/Infrared Imager/Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership (NPP) satellite is carried out through a Solar Diffuser (SD). The transmittance of the SD screen and the SD's Bidirectional Reflectance Distribution Function (BRDF) are measured before launch and tabulated, allowing the VIIRS sensor aperture spectral radiance to be accurately determined. The radiometric response of a detector is described by a quadratic polynomial of the detector's digital number (dn). The coefficients were determined before launch. Once on orbit, the coefficients are assumed to change by a common factor: the F-factor. The radiance scattered from the SD allows the determination of the F-factor. In this Proceeding, we describe the methodology and the associated algorithms in the determination of the F-factors and discuss the results.

  4. Radiometric calibration and atmospheric correction of satellite and aircraft data for FIFE

    NASA Technical Reports Server (NTRS)

    Goetz, Scott J.; Markham, Brian L.; Newcomer, Jeffery A.

    1992-01-01

    The satellite and aircraft radiometric calibration and atmospheric correction work carried out as part of the first International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) are summarized. A large volume (120 Gbytes) of radiometric data were acquired and derived from a number of different instruments on a variety of platforms. The same basic procedure was applied to each instrument: derive the most recent calibration coefficients for converting sensor counts to reflective spectral radiances; correct the radiances for earth-sun distance variations and incident solar spectral irradiance within the bandpass of each respective instrument channel at the top of the atmosphere; characterize the atmosphere for aerosols and absorbing gases; and derive apparent surface reflectance by correcting the exoatmospheric values for atmospheric attenuation. The same basic approach was used for surface temperature derivation. The results of this processing were verified by surface measurements, and corroborated by sensor intercomparisons.

  5. Radiometric--microbiologic assay of vitamin B-6: application to food analysis

    SciTech Connect

    Guilarte, T.R.; Shane, B.; McIntyre, P.A.

    1981-11-01

    A radiometric microbiologic assay for vitamin B-6 was applied to food analysis. The method was shown to be specific, reproducible and simpler than the standard turbidimetric microbiologic technique. The analysis of seven commercially available breakfast cereals was compared to a high performance liquid chromatography method. Three out of the seven cereals agreed when assayed with both methods (P greater than 0.1). Four cereals, however, differed in value considerably (P less than 0.05). Further studies are required to determine whether these differences were due to different extraction procedures used. The study showed that the new radiometric-microbiologic method can be used to measure total vitamin B-6 or, combined with a column separation procedure, to analyze for specific forms of the vitamin.

  6. Effects of point-spread function on calibration and radiometric accuracy of CCD camera.

    PubMed

    Du, Hong; Voss, Kenneth J

    2004-01-20

    The point-spread function (PSF) of a camera can seriously affect the accuracy of radiometric calibration and measurement. We found that the PSF can produce a 3.7% difference between the apparent measured radiance of two plaques of different sizes with the same illumination. This difference can be removed by deconvolution with the measured PSF. To determine the PSF, many images of a collimated beam from a He-Ne laser are averaged. Since our optical system is focused at infinity, it should focus this source to a single pixel. Although the measured PSF is very sharp, dropping 4 and 6 orders of magnitude and 8 and 100 pixels away from the point source, respectively, we show that the effect of the PSF as far as 100 pixels away cannot be ignored without introducing an appreciable error to the calibration. We believe that the PSF should be taken into account in all optical systems to obtain accurate radiometric measurements. PMID:14765928

  7. Determination of in vitro susceptibility of Mycobacterium tuberculosis to cephalosporins by radiometric and conventional methods

    SciTech Connect

    Heifets, L.B.; Iseman, M.D.; Cook, J.L.; Lindholm-Levy, P.J.; Drupa, I.

    1985-01-01

    Among eight cephalosporins and cephamycins tested in preliminary in vitro screening against Mycobacterium tuberculosis, the most promising for further study was found to be ceforanide, followed by ceftizoxime, cephapirin, and cefotaxime. Moxalactam, cefoxitin, cefamandole, and cephalothin were found to be not active enough against M. tuberculosis to be considered for further in vitro studies. The antibacterial activity of various ceforanide concentrations was investigated by three methods: (i) the dynamics of radiometric readings (growth index) in 7H12 broth; (ii) the number of CFU in the same medium; and (iii) the proportion method on 7H11 agar plates. There was a good correlation among the results obtained with these methods. The MIC for most strains ranged from 6.0 to 25.0 micrograms/ml. The BACTEC radiometric method is a reliable, rapid, and convenient method for preliminary screening and determination of the level of antibacterial activity of drugs not commonly used against M. tuberculosis.

  8. Reduction of Striping Noise in Overlapping LIDAR Intensity Data by Radiometric Normalization

    NASA Astrophysics Data System (ADS)

    Yan, Wai Yeung; Shaker, Ahmed

    2016-06-01

    To serve seamless mapping, airborne LiDAR data are usually collected with multiple parallel strips with one or two cross strip(s). Nevertheless, the overlapping regions of LiDAR data strips are usually found with unbalanced intensity values, resulting in the appearance of stripping noise. Despite that physical intensity correction methods are recently proposed, some of the system and environmental parameters are assumed as constant or not disclosed, leading to such an intensity discrepancy. This paper presents a new normalization technique to adjust the radiometric misalignment found in the overlapping LiDAR data strips. The normalization technique is built upon a second-order polynomial function fitted on the joint histogram plot, which is generated with a set of pairwise closest data points identified within the overlapping region. The method was tested on Teledyne Optech's Gemini dataset (at 1064 nm wavelength), where the LiDAR intensity data were first radiometrically corrected based on the radar (range) equation. Five land cover features were selected to evaluate the coefficient of variation (cv) of the intensity values before and after implementing the proposed method. Reduction of cv was found by 19% to 59% in the Gemini dataset, where the striping noise was significantly reduced in the radiometrically corrected and normalized intensity data. The Gemini dataset was also used to conduct land cover classification, and the overall accuracy yielded a notable improvement of 9% to 18%. As a result, LiDAR intensity data should be pre-processed with radiometric correction and normalization prior to any data manipulation.

  9. The absolute radiometric calibration of the advanced very high resolution radiometer

    NASA Technical Reports Server (NTRS)

    Slater, P. N.; Teillet, P. M.; Ding, Y.

    1988-01-01

    The need for independent, redundant absolute radiometric calibration methods is discussed with reference to the Thematic Mapper. Uncertainty requirements for absolute calibration of between 0.5 and 4 percent are defined based on the accuracy of reflectance retrievals at an agricultural site. It is shown that even very approximate atmospheric corrections can reduce the error in reflectance retrieval to 0.02 over the reflectance range 0 to 0.4.

  10. Photothermal radiometric time-domain inspection of solid specimen by moving line heat source

    NASA Astrophysics Data System (ADS)

    Hoshimiya, T.; Suzuki, M.; Takatsu, T.; Doi, N.; Endoh, H.

    2010-03-01

    The time-domain response of the temperature of solid specimen surface illuminated by a linearly-focused laser beam scanning over a solid specimen surface was theoretically formulated. The waveform is composed of surface diffusion and reflection components, both of which are represented by incomplete Gamma functions. Experimental results show photothermal radiometric signal increase caused by the reflection of heat flow at the internal defect boundary and agreed with calculated data qualitatively.

  11. Radiometric Characterization of the IKONOS, QuickBird, and OrbView-3 Sensors

    NASA Technical Reports Server (NTRS)

    Holekamp, Kara

    2007-01-01

    The NASA team of University of Arizona, South Dakota State University, and NASA SSC produce consistent results. The OrbView calibration coefficients do not appear to agree well with the NASA team estimate (approx. 20% difference). Discussions with GeoEye (TradeMark) (formerly ORBIMAGE(Registered TradeMark)) personnel are ongoing to update the calibration coefficients. The NASA team will continue to assess OrbView radiometric accuracy.

  12. Impact of the cameras radiometric resolution on the accuracy of determining spectral reflectance coefficients

    NASA Astrophysics Data System (ADS)

    Orych, A.; Walczykowski, P.; Jenerowicz, A.; Zdunek, Z.

    2014-11-01

    Nowadays remote sensing plays a very important role in many different study fields, i.e. environmental studies, hydrology, mineralogy, ecosystem studies, etc. One of the key areas of remote sensing applications is water quality monitoring. Understanding and monitoring of the water quality parameters and detecting different water contaminants is an important issue in water management and protection of whole environment and especially the water ecosystem. There are many remote sensing methods to monitor water quality and detect water pollutants. One of the most widely used method for substance detection with remote sensing techniques is based on usage of spectral reflectance coefficients. They are usually acquired using discrete methods such as spectrometric measurements. These however can be very time consuming, therefore image-based methods are used more and more often. In order to work out the proper methodology of obtaining spectral reflectance coefficients from hyperspectral and multispectral images, it is necessary to verify the impact of cameras radiometric resolution on the accuracy of determination of them. This paper presents laboratory experiments that were conducted using two monochromatic XEVA video sensors (400-1700 nm spectral data registration) with two different radiometric resolutions (12 and 14 bits). In view of determining spectral characteristics from images, the research team used set of interferometric filters. All data collected with multispectral digital video cameras were compared with spectral reflectance coefficients obtained with spectroradiometer. The objective of this research is to find the impact of cameras radiometric resolution on reflectance values in chosen wavelength. The main topic of this study is the analysis of accuracy of spectral coefficients from sensors with different radiometric resolution. By comparing values collected from images acquired with XEVA sensors and with the curves obtained with spectroradiometer it

  13. Radiometric calibration of DMSP-OLS sensor using VIIRS day/night band

    NASA Astrophysics Data System (ADS)

    Shao, Xi; Cao, Changyong; Zhang, Bin; Qiu, Shi; Elvidge, Christopher; Von Hendy, Michael

    2014-11-01

    Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) has been collecting global night light imaging data for more than 40 years. With the launch of Suomi-NPP satellite in 2011, the Day/Night Band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) represents a major advancement in night time imaging capabilities because it surpasses DMSP-OLS in having broader radiometric measurement range, more accurate radiometric calibration, finer spatial resolution, and better geometric quality. DMSP-OLS sensor does not have on-board calibration and data is recorded as digital number (DN). Therefore, VIIRS-DNB provides opportunities to perform quantitative radiometric calibration of DMSP-OLS sensor. In this paper, vicarious radiometric calibration of DMSP-OLS at night under lunar illumination is performed. Events were selected when satellite flies above Dome C in Antarctic at night and the moon illuminates the site with lunar phase being more than quarter moon. Additional event selection criteria to limit solar and lunar zenith angle range have been applied to ensure no influence of stray light effects and adequate lunar illumination. The data from DMSP-OLS and VIIRS-DNB were analyzed to derive the characteristic radiance or DN for the region of interest. The scaling coefficient for converting DMSP-OLS DN values into radiance is determined to optimally merge the observation of DMSP-OLS into VIIRS-DNB radiance data as a function of lunar phases. Calibrating the nighttime light data collected by the DMSP-OLS sensors into radiance unit can enable applications of using both sensor data and advance the applications of night time imagery data.

  14. A New Automatic System for Angular Measurement and Calibration in Radiometric Instruments

    PubMed Central

    Marquez, Jose Manuel Andujar; Bohórquez, Miguel Ángel Martínez; Garcia, Jonathan Medina; Nieto, Francisco Jose Aguilar

    2010-01-01

    This paper puts forward the design, construction and testing of a new automatic system for angular-response measurement and calibration in radiometric instruments. Its main characteristics include precision, speed, resolution, noise immunity, easy programming and operation. The developed system calculates the cosine error of the radiometer under test by means of a virtual instrument, from the measures it takes and through a mathematical procedure, thus allowing correcting the radiometer with the aim of preventing cosine error in its measurements. PMID:22319320

  15. A procedure for radiometric recalibration of Landsat 5 TM reflective-band data

    USGS Publications Warehouse

    Chander, G.; Haque, M.O.; Micijevic, E.; Barsi, J.A.

    2010-01-01

    From the Landsat program's inception in 1972 to the present, the Earth science user community has been benefiting from a historical record of remotely sensed data. The multispectral data from the Landsat 5 (L5) Thematic Mapper (TM) sensor provide the backbone for this extensive archive. Historically, the radiometric calibration procedure for the L5 TM imagery used the detectors' response to the internal calibrator (IC) on a scene-by-scene basis to determine the gain and offset for each detector. The IC system degraded with time, causing radiometric calibration errors up to 20%. In May 2003, the L5 TM data processed and distributed by the U.S. Geological Survey (USGS) Earth Resources Observation and Science Center through the National Landsat Archive Production System (NLAPS) were updated to use a lifetime lookup-table (LUT) gain model to radiometrically calibrate TM data instead of using scene-specific IC gains. Further modification of the gain model was performed in 2007. The L5 TM data processed using IC prior to the calibration update do not benefit from the recent calibration revisions. A procedure has been developed to give users the ability to recalibrate their existing level-1 products. The best recalibration results are obtained if the work-order report that was included in the original standard data product delivery is available. However, if users do not have the original work-order report, the IC trends can be used for recalibration. The IC trends were generated using the radiometric gain trends recorded in the NLAPS database. This paper provides the details of the recalibration procedure for the following: 1) data processed using IC where users have the work-order file; 2) data processed using IC where users do not have the work-order file; 3) data processed using prelaunch calibration parameters; and 4) data processed using the previous version of the LUT (e.g., LUT03) that was released before April 2, 2007.

  16. Prime candidate earth targets for the post-launch radiometric calibration of space-based optical imaging instruments

    USGS Publications Warehouse

    Teillet, P.M.; Barsi, J.A.; Chander, G.; Thome, K.J.

    2007-01-01

    This paper provides a comprehensive list of prime candidate terrestrial targets for consideration as benchmark sites for the post-launch radiometric calibration of space-based instruments. The key characteristics of suitable sites are outlined primarily with respect to selection criteria, spatial uniformity, and temporal stability. The establishment and utilization of such benchmark sites is considered an important element of the radiometric traceability of satellite image data products for use in the accurate monitoring of environmental change.

  17. Radiometric Calibration of a Dual-Wavelength, Full-Waveform Terrestrial Lidar.

    PubMed

    Li, Zhan; Jupp, David L B; Strahler, Alan H; Schaaf, Crystal B; Howe, Glenn; Hewawasam, Kuravi; Douglas, Ewan S; Chakrabarti, Supriya; Cook, Timothy A; Paynter, Ian; Saenz, Edward J; Schaefer, Michael

    2016-01-01

    Radiometric calibration of the Dual-Wavelength Echidna(®) Lidar (DWEL), a full-waveform terrestrial laser scanner with two simultaneously-pulsing infrared lasers at 1064 nm and 1548 nm, provides accurate dual-wavelength apparent reflectance (ρ(app)), a physically-defined value that is related to the radiative and structural characteristics of scanned targets and independent of range and instrument optics and electronics. The errors of ρ(app) are 8.1% for 1064 nm and 6.4% for 1548 nm. A sensitivity analysis shows that ρ(app) error is dominated by range errors at near ranges, but by lidar intensity errors at far ranges. Our semi-empirical model for radiometric calibration combines a generalized logistic function to explicitly model telescopic effects due to defocusing of return signals at near range with a negative exponential function to model the fall-off of return intensity with range. Accurate values of ρ(app) from the radiometric calibration improve the quantification of vegetation structure, facilitate the comparison and coupling of lidar datasets from different instruments, campaigns or wavelengths and advance the utilization of bi- and multi-spectral information added to 3D scans by novel spectral lidars. PMID:26950126

  18. Designing an in-flight airborne calibration site using experience from vicarious radiometric satellite calibration

    NASA Astrophysics Data System (ADS)

    Livens, Stefan; Debruyn, Walter; Sterckx, Sindy; Reusen, Ils

    2011-11-01

    Laboratory calibration of electro-optical sensors is preferably complemented by regular in-flight verification. This checks whether the lab calibration parameters remain valid or recalibration is necessary. In-flight verification can be achieved by vicarious calibration using in-flight measurements of calibration targets. We intend to identify and design a set of suitable radiometric calibration targets. For this, we borrow from expertise gained with the PROBA-V satellite calibration system, which uses multiple vicarious methods relying on diverse natural on-ground targets. Besides reflectance based calibration using ground measurements, the PROBA-V calibration methods are unproven for use in airborne calibration. The selected targets should be suitable for the calibration of both multispectral and hyperspectral imagers. We start from general requirements for radiometric targets and investigate their applicability to airborne calibration. From this we identify two possible sets of natural calibration sites in Belgium. One set, located in the Campine region, contains small water bodies and sandy lakesides. Another set is located in the Westhoek region near the Belgian coast. It offers better suitable water bodies, as well as sandy areas, grass fields and dark targets. Airborne calibration lends itself to the use of smaller artifical targets. We propose to complement the natural targets with a portable target consisting of agricultural nets with different densities. The definition of sets of calibration targets, both natural and artificial can facilitate the investigation of the usability of vicarious targets and method for inflight radiometric verification.

  19. Radiometric 81Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica.

    PubMed

    Buizert, Christo; Baggenstos, Daniel; Jiang, Wei; Purtschert, Roland; Petrenko, Vasilii V; Lu, Zheng-Tian; Müller, Peter; Kuhl, Tanner; Lee, James; Severinghaus, Jeffrey P; Brook, Edward J

    2014-05-13

    We present successful (81)Kr-Kr radiometric dating of ancient polar ice. Krypton was extracted from the air bubbles in four ∼350-kg polar ice samples from Taylor Glacier in the McMurdo Dry Valleys, Antarctica, and dated using Atom Trap Trace Analysis (ATTA). The (81)Kr radiometric ages agree with independent age estimates obtained from stratigraphic dating techniques with a mean absolute age offset of 6 ± 2.5 ka. Our experimental methods and sampling strategy are validated by (i) (85)Kr and (39)Ar analyses that show the samples to be free of modern air contamination and (ii) air content measurements that show the ice did not experience gas loss. We estimate the error in the (81)Kr ages due to past geomagnetic variability to be below 3 ka. We show that ice from the previous interglacial period (Marine Isotope Stage 5e, 130-115 ka before present) can be found in abundance near the surface of Taylor Glacier. Our study paves the way for reliable radiometric dating of ancient ice in blue ice areas and margin sites where large samples are available, greatly enhancing their scientific value as archives of old ice and meteorites. At present, ATTA (81)Kr analysis requires a 40-80-kg ice sample; as sample requirements continue to decrease, (81)Kr dating of ice cores is a future possibility. PMID:24753606

  20. Radiometric Calibration of the AWiFS Using Vicarious Calibration Techniques

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Holekamp, Kara

    2007-01-01

    A radiometric calibration assessment of the AWiFS (Advanced Wide Field Sensor) on the Indian Remote Sensing Resourcesat-1 satellite was performed by the NASA Applied Research & Technology Project Office (formerly the Applied Sciences Directorate) at the John C. Stennis Space Center. A reflectance-based vicarious calibration approach, requiring ground-based measurements coincident with satellite acquisitions and radiative transfer calculations, was used to estimate at-sensor radiance. The AWiFS is a 4-band, multispectral, moderate-resolution (60 m) imaging sensor that operates in the visible through short-wave infrared spectrum and is currently being considered as a Landsat-like alternative. Several study sites near the Stennis Space Center that attempted to span the dynamic range of the sensor were employed. Satellite at-sensor radiance values were compared to those estimated to determine the sensor's radiometric accuracy. The results of this evaluation provide the user community with an independent assessment of the radiometric accuracy of AWiFS image products, which are commercially available through GeoEye. These results are an extension of an independent assessment made by the University of Arizona Remote Sensing Group, the South Dakota State University Satellite Calibration Group & Image Processing Lab, and the NASA Applied Sciences Directorate at the John C. Stennis Space Center the previous year.

  1. Simultaneous observations of aerosols, clouds, and radiometric fluxes using light-weight autonomous UAVs

    NASA Astrophysics Data System (ADS)

    Roberts, G.; Ramanathan, V.; Corrigan, C.; Ramana, M.; Nguyen, H.

    2006-12-01

    The Maldives Air Campaign (MAC) demonstrated a novel application of stacked autonomous unmanned aerial vehicles (AUAVs) for atmospheric science research; see abstract by Ramanathan et al. in this session. Simultaneous observations from three AUAVs of aerosols, clouds and radiometric fluxes provide insight into aerosol-cloud interactions and subsequent effects on cloud radiative properties. Ground-based measurements of cloud condensation nuclei (CCN) also quantify the cloud-nucleating ability of the boundary layer aerosols. During the experiment, long-range transport of aerosols from the Arabian Peninsula and India was observed and its impact of cloud physical and radiometric properties has been detected. To accomplish this campaign, aerosol, cloud, radiometric instruments, and an integrated data acquisition system have been miniaturized with a total payload weight and power less than 5 kg and 50 W, respectively. The AUAV payloads are mission-specific and outfitted to perform a defined set of measurements depending on the scientific goals. These measurements include aerosol concentration, aerosol size distribution, aerosol absorption, cloud drop concentration and size distribution, solar radiation fluxes (visible and broadband), atmospheric turbulence, temperature, pressure, and relative humidity. The data collected during the MAC campaign has been validated using standard calibration routines in conjunction with comparisons to ground- based instruments in both laboratory and in situ (in aircraft) settings. All instruments have been thoroughly tested and calibrated prior to deployment.

  2. Radiometric 81Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica

    PubMed Central

    Buizert, Christo; Baggenstos, Daniel; Jiang, Wei; Purtschert, Roland; Petrenko, Vasilii V.; Lu, Zheng-Tian; Müller, Peter; Kuhl, Tanner; Lee, James; Severinghaus, Jeffrey P.; Brook, Edward J.

    2014-01-01

    We present successful 81Kr-Kr radiometric dating of ancient polar ice. Krypton was extracted from the air bubbles in four ∼350-kg polar ice samples from Taylor Glacier in the McMurdo Dry Valleys, Antarctica, and dated using Atom Trap Trace Analysis (ATTA). The 81Kr radiometric ages agree with independent age estimates obtained from stratigraphic dating techniques with a mean absolute age offset of 6 ± 2.5 ka. Our experimental methods and sampling strategy are validated by (i) 85Kr and 39Ar analyses that show the samples to be free of modern air contamination and (ii) air content measurements that show the ice did not experience gas loss. We estimate the error in the 81Kr ages due to past geomagnetic variability to be below 3 ka. We show that ice from the previous interglacial period (Marine Isotope Stage 5e, 130–115 ka before present) can be found in abundance near the surface of Taylor Glacier. Our study paves the way for reliable radiometric dating of ancient ice in blue ice areas and margin sites where large samples are available, greatly enhancing their scientific value as archives of old ice and meteorites. At present, ATTA 81Kr analysis requires a 40–80-kg ice sample; as sample requirements continue to decrease, 81Kr dating of ice cores is a future possibility. PMID:24753606

  3. Relative Radiometric Normalization and Atmospheric Correction of a SPOT 5 Time Series

    PubMed Central

    Hajj, Mahmoud El; Bégué, Agnès; Lafrance, Bruno; Hagolle, Olivier; Dedieu, Gérard; Rumeau, Matthieu

    2008-01-01

    Multi-temporal images acquired at high spatial and temporal resolution are an important tool for detecting change and analyzing trends, especially in agricultural applications. However, to insure a reliable use of this kind of data, a rigorous radiometric normalization step is required. Normalization can be addressed by performing an atmospheric correction of each image in the time series. The main problem is the difficulty of obtaining an atmospheric characterization at a given acquisition date. In this paper, we investigate whether relative radiometric normalization can substitute for atmospheric correction. We develop an automatic method for relative radiometric normalization based on calculating linear regressions between unnormalized and reference images. Regressions are obtained using the reflectances of automatically selected invariant targets. We compare this method with an atmospheric correction method that uses the 6S model. The performances of both methods are compared using 18 images from of a SPOT 5 time series acquired over Reunion Island. Results obtained for a set of manually selected invariant targets show excellent agreement between the two methods in all spectral bands: values of the coefficient of determination (r2 exceed 0.960, and bias magnitude values are less than 2.65. There is also a strong correlation between normalized NDVI values of sugarcane fields (r2 = 0.959). Despite a relative error of 12.66% between values, very comparable NDVI patterns are observed.

  4. Radiometric Calibration of a Dual-Wavelength, Full-Waveform Terrestrial Lidar

    PubMed Central

    Li, Zhan; Jupp, David L. B.; Strahler, Alan H.; Schaaf, Crystal B.; Howe, Glenn; Hewawasam, Kuravi; Douglas, Ewan S.; Chakrabarti, Supriya; Cook, Timothy A.; Paynter, Ian; Saenz, Edward J.; Schaefer, Michael

    2016-01-01

    Radiometric calibration of the Dual-Wavelength Echidna® Lidar (DWEL), a full-waveform terrestrial laser scanner with two simultaneously-pulsing infrared lasers at 1064 nm and 1548 nm, provides accurate dual-wavelength apparent reflectance (ρapp), a physically-defined value that is related to the radiative and structural characteristics of scanned targets and independent of range and instrument optics and electronics. The errors of ρapp are 8.1% for 1064 nm and 6.4% for 1548 nm. A sensitivity analysis shows that ρapp error is dominated by range errors at near ranges, but by lidar intensity errors at far ranges. Our semi-empirical model for radiometric calibration combines a generalized logistic function to explicitly model telescopic effects due to defocusing of return signals at near range with a negative exponential function to model the fall-off of return intensity with range. Accurate values of ρapp from the radiometric calibration improve the quantification of vegetation structure, facilitate the comparison and coupling of lidar datasets from different instruments, campaigns or wavelengths and advance the utilization of bi- and multi-spectral information added to 3D scans by novel spectral lidars. PMID:26950126

  5. Radiometric calibration of Advanced Land Imager using reflectance-based results between 2001 and 2005

    NASA Astrophysics Data System (ADS)

    McCorkel, J.; Thome, K.; Biggar, S.; Kuester, M.

    2006-08-01

    The Landsat series of sensors have supplied the remote sensing community with a continuous data set dating to the early 1970s. An important aspect of retaining the continuity of these data is that a Landsat follow-on as well as current Landsat instruments must be understood radiometrically throughout their mission. The Advanced Land Imager (ALI), for example, was developed as a prototype for the next generation of Landsat Instruments, and as such there was a significant effort to understand its radiometric characteristics as well as how it compares with previous Landsat sensors. The Remote Sensing Group at the University of Arizona has been part of this effort since the late 2000 launch of ALI through the use of the reflectance-based method of vicarious calibration. The reflectance-based approach consists of ground-based measurements of atmospheric conditions and surface reflectance at the time of satellite overpass to predict the at-sensor radiance seen by the sensor under study. The work compares results from the reflectance-based approach obtained from well-characterized test sites such as Railroad Valley Playa in Nevada and Ivanpah Playa in California as applied to ALI, Landsat-5 TM, and Landsat-7 EMT+. The results from the comparison use a total of 14 ALI dates spanning in time from 2001 to late 2005 and show that ALI agrees with the current radiometric results from TM and ETM+ to within 5%.

  6. Calibrating Late Quaternary terrestrial climate signals: radiometrically dated pollen evidence from the southern Sierra Nevada, USA

    USGS Publications Warehouse

    Litwin, Ronald J.; Smoot, Joseph P.; Durika, Nancy J.; Smith, George I.

    1999-01-01

    We constructed a radiometrically calibrated proxy record of Late Pleistocene and Holocene climate change exceeding 230,000 yr duration, using pollen profiles from two cores taken through age-equivalent dry lakes - one core having greater age control (via 230Th alpha mass-spectrometry) and the other having greater stratigraphic completeness. The better dated of these two serial pollen records (Searles Lake) served as a reference section for improving the effective radiometric age control in a nearby and more complete pollen record (Owens Lake) because they: (1) are situated ~90 km apart in the same drainage system (on, and immediately leeward of, the eastern flank of the Sierra Nevada), and (2) preserved strikingly similar pollen profiles and concordant sequences of sedimentological changes. Pollen assemblages from both lakes are well preserved and diverse, and document serial changes in Late Pleistocene and Holocene plant zone distribution and composition in the westernmost Great Basin; they consist of taxa now inhabiting montane forest, woodland, steppe, and desert-scrub environments. The studied core intervals are interpreted here to be the terrestrial equivalent of marine δ18O stages 1 through 9; these pollen profiles now appear to be among the best radiometrically dated Late Pleistocene records of terrestrial climate change known.

  7. Trending of Suomi-NPP VIIRS radiometric performance with lunar band ratio

    NASA Astrophysics Data System (ADS)

    Shao, Xi; Choi, Taeyoung; Cao, Changyong; Blonski, Slawomir; Wang, Wenhui; Ban, Yan

    2014-11-01

    Radiometric stability of the lunar surface and its smooth reflectance spectrum makes the moon an ideal target for calibrating satellite-based hyper/multi-band visible imagers, as demonstrated in several lunar calibration studies of satellite radiometers. Most of the lunar calibrations rely on using lunar irradiance models to calibrate satellite radiometers, which require the lunar irradiance model to be highly accurate. In this paper, we use Lunar Band Ratio (LBR) to trend satellite radiometer performance so that the usage of lunar irradiance model is not required. The LBR method is applied to monitor long term radiometric performance of VIIRS (Visible Infrared Imaging Radiometer Suite) onboard Suomi-NPP. VIIRS observes moon at nearly the same lunar phase angle through Earth view during scheduled spacecraft maneuver. Total lunar digital number are calculated for each VIIRS reflective solar bands (RSBs) from lunar observations and one of the most stable bands of VIIRS such as M4 band is chosen as the reference band for calculating the band ratio. LBRs are compared with the degradation factors derived from VIIRS operational radiometric calibration of RSBs using onboard solar diffuser. The LBR analysis reveals that M6 and M7 degrade the fastest and agree well with the trending independently determined from onboard solar diffuser. For stable bands such as M3-M4 of VIIRS, the variation range of band ratios of M2/M4 and M3/M4 are all within 0.6%, indicating the LBR can be used to reveal the sub percent band to band stability. For M11 band of VIIRS, there have been large uncertainties in verifying its radiometric performance using vicarious ground targets. LBR of M11 provides an independent and useful radiometric stability monitoring tool for verifying the relative stability of M11 band. The LBR analysis also shows that band-to-band variability in the spectrally similar band pairs such as I2 vs. M7 and I3 vs. M10 of VIIRS are consistent within 0.2%. It is demonstrated

  8. [VMTBB-Based Spectral Radiometric Calibration of NIR Fiber Coupled Spectrometer].

    PubMed

    Zheng, Feng; Liu, Li-ying; Liu, Xiao-xi; Li, Ye; Shi, Xiao-guang; Zhang, Guo-yu; Huan, Ke-wei

    2015-09-01

    The medium temperature black body (MTBB) is conventional high precision equipment used as spectral radiometric scale in infrared spectral region. However, in near-infrared (NIR) spectral region, there are few papers about spectral radiometric calibration by using MTBB, that is because NIR spectral region is the borderland of its effective spectral region. The main research of this paper is spectral radiometric calibration method by using MTBB in NIR spectral region. Accordingly, this paper is devoted mostly to a discussion of how the calibration precision could be affected by selecting different structural parameters of calibration model. The purpose of this paper is to present the results of research and provide technical reference for improving the traceability in NIR spectral radiometric calibration. In this paper, a NIR fiber coupled spectrometer, whose wavelength range covers from 950 to 1700 nm, has been calibrated by a MTBB with adjustable temperature range from 50 to 1050 °C. Concentrating on calibration process, two key points have been discussed. For one thing, the geometric factors of radiation transfer model of the calibration systems have been compared between traditional structure and fiber direct-coupled structure. Because the fiber direct-coupled model is simple and effective, it has been selected instead of traditional model based on the radiation transfer between two coaxial discs. So, it is an advantaged radiation transfer model for radiometric calibration of fiber coupled spectrometer. For another thing, the relation between calibration accuracy and structural parameters of calibration model has been analyzed intensively. The root cause is scale feature of attribute of calibration data itself, which is the nonlinear structure in scales of spectral data. So, the high precision calibration needs nonlinear calibration model, and the uniform sampling for scale feature is also very important. Selecting sample is an inevitable problem when the

  9. Serum susceptibility of bovine pasteurellas.

    PubMed Central

    Blau, K A; Ward, A C; Prieur, D J; Corbeil, L B

    1987-01-01

    In this study, the serum sensitivity of 23 P. haemolytica isolates and 18 P. multocida isolates was determined by incubating dilutions of bacteria with equal volumes of fresh or heat-inactivated bovine serum for one, two, or three hours. Clinical isolates of both Pasteurella species were resistant to serum, whereas isolates from asymptomatic cattle varied in serum susceptibility. The classical pathway of complement appeared to be the principal means of complement mediated killing as detected by incubation in the presence or absence of EGTA-MgCl2. Lyzozyme and iron saturation of serum did not greatly affect serum susceptibility with either of the Pasteurella species. PMID:3300919

  10. The multi-temporal comparisons from high resolution KOMPSAT-2 image with dehaze and radiometric normalization methods

    NASA Astrophysics Data System (ADS)

    Yeom, J.; Kim, H.; Kim, Y.; Kim, J.

    2011-12-01

    The KOrea MultiPurpose SAtellite-2 (KOMPSAT-2) satellite developed by Korea Aerospace Research Institute (KARI) was launched on July 28, 2006 in northern Russia and has continued successful operations for almost 4 years past the initial mission. KOMPSAT-2 has been providing 1-m resolution of panchromatic images and 4-m resolution multi spectral images all over the world. In the case optical satellites, haze is considered as an unwanted obstacle when estimating surface information. Usually, it is masked with subjective threshold method to reduce contaminated area which may give wrong information to user. In this study, haze transformation is applied for determining haze area and inferring surface digital number of KOMPSAT-2 under haze condition. When comparing differently observed images, radiometric normalized is the essential process to interpret variations of surface phenomena, especially in land surface change detection. There are mainly two kinds of methods to correct the different radiometric values. One is the absolute radiometric normalization intending for trying to estimate the actual surface reflectance, and another is relative radiometric normalization, which is linearly rectifying the observed image at the specific time to the others at different time for common radiometric scale. In this study, relative radiometric normalization method is used for correcting differences among images caused by inconsistent observation condition. When normalizing multi-date images, BRDF (Bidirectional Reflectance Distribution Function) also considered for reducing anisotropy effects caused by relative solar-sensor-target geometry. Processed surface reflectance based on dehazing and radiometric normalization show better results when comparing multi-date images than original reflectance images.

  11. Influence of Lossy Compressed DEM on Radiometric Correction for Land Cover Classification of Remote Sensing Images

    NASA Astrophysics Data System (ADS)

    Moré, G.; Pesquer, L.; Blanes, I.; Serra-Sagristà, J.; Pons, X.

    2012-12-01

    World coverage Digital Elevation Models (DEM) have progressively increased their spatial resolution (e.g., ETOPO, SRTM, or Aster GDEM) and, consequently, their storage requirements. On the other hand, lossy data compression facilitates accessing, sharing and transmitting large spatial datasets in environments with limited storage. However, since lossy compression modifies the original information, rigorous studies are needed to understand its effects and consequences. The present work analyzes the influence of DEM quality -modified by lossy compression-, on the radiometric correction of remote sensing imagery, and the eventual propagation of the uncertainty in the resulting land cover classification. Radiometric correction is usually composed of two parts: atmospheric correction and topographical correction. For topographical correction, DEM provides the altimetry information that allows modeling the incidence radiation on terrain surface (cast shadows, self shadows, etc). To quantify the effects of the DEM lossy compression on the radiometric correction, we use radiometrically corrected images for classification purposes, and compare the accuracy of two standard coding techniques for a wide range of compression ratios. The DEM has been obtained by resampling the DEM v.2 of Catalonia (ICC), originally having 15 m resolution, to the Landsat TM resolution. The Aster DEM has been used to fill the gaps beyond the administrative limits of Catalonia. The DEM has been lossy compressed with two coding standards at compression ratios 5:1, 10:1, 20:1, 100:1 and 200:1. The employed coding standards have been JPEG2000 and CCSDS-IDC; the former is an international ISO/ITU-T standard for almost any type of images, while the latter is a recommendation of the CCSDS consortium for mono-component remote sensing images. Both techniques are wavelet-based followed by an entropy-coding stage. Also, for large compression ratios, both techniques need a post processing for correctly

  12. Multi-point radiometric calibration method based on complex spectrum of Fourier transform spectrometer

    NASA Astrophysics Data System (ADS)

    He, Qian; Wang, Guangping; Wu, Jingli; Li, Junwei

    2014-11-01

    As the impact of the instrument internal error, external interference and other factors, the interferogram measured by Fourier transform spectrometer is asymmetric, result in the complex outcome after Fourier transform. Currently, most radiometric calibration method used for Fourier transform spectrometer is usually based on real spectrums, which is converted from the above complex spectrum by calculating magnitude value or make the phase correction first. Proceed from error sources and mechanisms of the Fourier transform spectrometer, we propose a multi-point radiometric calibration method based on complex spectral data to improve the processing efficiency and accuracy, which is obtained by the original interferogram via Fourier transform. We solving the instrument response function include linear gain and offset by complex spectrum above to calculate complex spectral radiance. Compared with the traditional method based on real spectrum, the present efficient method does not limited to real spectrum and the phase correction is not required. In this paper, we use BOMEM's MR304 Fourier transform infrared spectrometer and the DCN1000N3 blackbody made by HGH Infrared Systems to carry out the radiation calibration experiment in laboratory. The results show that, the amplitude of complex radiance spectrum obtained by this method has a high consistency with the theoretical value, while the extra imaginary spectrum is similar with the difference between results and theoretical value in absolute value and trends. It proved that, this multi-point radiometric calibration method by using the amplitude of complex spectral data is highly reliable; meanwhile, the imaginary spectrum can reflect the calibration error very well and offer a new technical approach for accuracy evaluation research.

  13. OCRA radiometric cloud fractions for GOME-2 on MetOp-A/B

    NASA Astrophysics Data System (ADS)

    Lutz, R.; Loyola, D.; Gimeno García, S.; Romahn, F.

    2015-12-01

    This paper describes an approach for cloud parameter retrieval (radiometric cloud fraction estimation) using the polarization measurements of the Global Ozone Monitoring Experiment-2 (GOME-2) on-board the MetOp-A/B satellites. The core component of the Optical Cloud Recognition Algorithm (OCRA) is the calculation of monthly cloud-free reflectances for a global grid (resolution of 0.2° in longitude and 0.2° in latitude) and to derive radiometric cloud fractions. These cloud fractions will serve as a priori information for the retrieval of cloud top height (CTH), cloud top pressure (CTP), cloud top albedo (CTA) and cloud optical thickness (COT) with the Retrieval Of Cloud Information using Neural Networks (ROCINN) algorithm. This approach is already being implemented operationally for the GOME/ERS-2 and SCIAMACHY/ENVISAT sensors and here we present version 3.0 of the OCRA algorithm applied to the GOME-2 sensors. Based on more than six years of GOME-2A data (February 2007-June 2013), reflectances are calculated for ≈ 35 000 orbits. For each measurement a degradation correction as well as a viewing angle dependent and latitude dependent correction is applied. In addition, an empirical correction scheme is introduced in order to remove the effect of oceanic sun glint. A comparison of the GOME-2A/B OCRA cloud fractions with co-located AVHRR geometrical cloud fractions shows a general good agreement with a mean difference of -0.15±0.20. From operational point of view, an advantage of the OCRA algorithm is its extremely fast computational time and its straightforward transferability to similar sensors like OMI (Ozone Monitoring Instrument), TROPOMI (TROPOspheric Monitoring Instrument) on Sentinel 5 Precursor, as well as Sentinel 4 and Sentinel 5. In conclusion, it is shown that a robust, accurate and fast radiometric cloud fraction estimation for GOME-2 can be achieved with OCRA by using the polarization measurement devices (PMDs).

  14. Radiometric uncertainty per pixel for the Sentinel-2 L1C products

    NASA Astrophysics Data System (ADS)

    Gorroño, Javier; Gascon, Ferran; Fox, Nigel P.

    2015-10-01

    In the framework of the European Union Copernicus programme, the European Space Agency (ESA) has launched the Sentinel-2 (S2) Earth Observation (EO) mission which provides optical high spatial resolution imagery. Here is presented a tool, S2-RUT, (Sentinel-2 Radiometric Uncertainty Tool) allowing estimation of the radiometric uncertainties associated to each pixel using as input the top-of-atmosphere (TOA) reflectance images provided by ESA. The Sentinel-2 radiometric analysis focuses on the review of the pre- and post-launch characterisations in order to specify the uncertainty contributors at a pixel level and allow changes to be proposed in the uncertainty contributors where necessary. The identified uncertainty contributors are combined using a metrological Guide to Expression of Uncertainty in Measurement' (GUM) model that is validated by comparing the results to a multivariate Monte Carlo Method (MCM). Specific contributors of the TOA reflectance are initially characterised and its future integration in the tool is discussed. The software implementation of the S2-RUT tool relies on the flexibility of the JPEG2000 standard using partial decoding. Auxiliary information for the uncertainty calculation is extracted from the metadata and quality masks integrated in the L1C product. In addition, using the detector footprint mask it is possible to account for parameters dependent on the neighbouring pixels and/or detector module. The L1C uncertainty is coded using 1 byte with an extra optional byte for complementary information. The resulting images and the metadata are directly appended to the original L1C product.

  15. A novel solution for car traffic control based on radiometric microwave devices

    NASA Astrophysics Data System (ADS)

    Soldovieri, Francesco; Denisov, Alexander; Speziale, Victor

    2014-05-01

    The significant problem of traffic in big cities, connected with huge and building up quantity of automobile cars, demands for novel strategies, based on nonconventional solutions, in order to improve system traffic control, especially at crossroads. As well known, the usual solution is based on the time relay, which requires the installation of a fixed traffic interval (signal light switching) at a crossroad; this solution is low cost, but does not account for the actual traffic conditions. Therefore, in the recent years, attention is towards to new designs, where the monitoring of the and control of traffic is carried out by using various methods including, optical, the infrared, magnetic, radar tracking, acoustical ones. In this work, we discuss the deployment of high sensitivity radiometric systems and radiometers(sensor) in the microwave range [1, 2]. In fact, the radiometer as "sensor" can provide an always updated information about the car traffic in any weather condition and in absence or low visibility conditions. In fact, the radiometric sensor detects the cars thanks to the different behavior of the car roofs which reflect the cold sky whereas the road asphalt is visible as warm object (at around outside temperature). [1] A. G. Denisov, V. P. Gorishnyak, S. E. Kuzmin et al., "Some experiments concerning resolution of 32 sensors passive 8mm wave imaging system," in Proceedings of the International Symposium on Space Terahertz Technology (ISSTT '09), Charlottesville, Va, USA, April 2009. [2] F. Soldovieri, A. Natale, V. Gorishnyak, A. Pavluchenko, A. Denisov, and L. Chen, "Radiometric Imaging for Monitoring and Surveillance Issues," International Journal of Antennas and Propagation, vol. 2013, Article ID 272561, 8 pages, 2013. doi:10.1155/2013/272561.

  16. Pre-flight radiometric and spectral calibration of Resourcesat-2A-LISS3* payload

    NASA Astrophysics Data System (ADS)

    Seth, Harish; Detroja, M. P.; Padmanabhan, Deepa; Raj, Vedant; Kumar, Anil; Sarkar, S. S.

    2016-05-01

    Resourcesat-2A is a follow-on mission of Resourcesat-2, belongs to Indian Remote Sensing Program. It is expected to be launched in 2016 and is dedicated mainly to agricultural applications. One of the payloads, LISS3* is a medium resolution (23.5 m) sensor having four multispectral bands from 450 to 1650 nm. These spectral bands are named as B2 (550 nm), B3 (650 nm), B4 (815 nm) and B5 (1625 nm) respectively covering Visible, Near Infrared (NIR) and Short Wave Infrared (SWIR) regions. In order to provide quality data to the user community for long term scientific applications pre-flight ground calibration is carried out. This paper describes pre-flight spectral and radiometric calibration of LISS3* payload and its performance evaluation. Since it is a continuity mission to Resourcesat-2, which was launched in April 2011 so for generating long-term data record and correlation with previous observations, its parameters are compared with Resourcesat-2 LISS3* payload. The main spectral parameters like central wavelength, and pass band is determined using system level spectral response and compared for both the mission and differences are outlined. The next important exercise is pre-flight radiometric calibration, which was carried out in laboratory using a standard integrating sphere traceable to NIST standards. This paper highlights the technique adopted during pre-flight calibration of the radiometric response and performance assessment of all 4 bands of LISS3* in terms of major electro-optical parameters like Signal to Noise Ratio (SNR), Saturation Radiance (SR) etc. The observed SR shows that the sensor can measure spectral radiance from Earth up to 100% albedo.

  17. Radiometric trend of lunar calibration compared with vicarious calibration for GOSAT

    NASA Astrophysics Data System (ADS)

    Shiomi, K.; Kawakami, S.; Kuze, A.; Suto, H.; Hashiguchi, T.; Kataoka, F.; Higuchi, R.; Bruegge, C. J.; Schwandner, F. M.; Chapsky, L.

    2014-12-01

    GOSAT observes a nearly full moon for the on-orbit radiometric calibration of the FTS SWIR bands and the CAI. Lunar calibrations are operated in April/May for investigation of continuous annual radiometric trends and in June/July, corresponding to the annual Railroad Valley Cal/Val campaign. JAXA's Greenhouse Gases Observing Satellite (GOSAT) is since 2009 in polar orbit to monitor greenhouse gases such as CO2 and CH4 from space. GOSAT consists of a Fourier Transform Spectrometer (TANSO-FTS) and a Cloud and Aerosol Imager (TANSO-CAI). The FTS has 3 polarized SWIR narrow bands and a TIR wide band. The FTS observes globally with gridded points of 10 km FOV using discrete pointing. The CAI carries 4 radiometers in the UV to SWIR with high spatial resolution of 0.5-1.5 km and a wide swath of 1000 km. Since the 3rd year, lunar calibration has been planned to observe at a phase angle around 7 degrees from normal incidence. This choice avoids the reflectance opposition surge in order to target the nearly-unchanged and brightest reflectance as a function of phase angle. The Railroad Valley vicarious calibration campaign is conducted by measuring the surface reflectance and atmospheric parameters coincident with a dedicated GOSAT target observation, to derive top-of-the-atmosphere radiance. The nadir surface reflectance is collected in 500x500 m areas corresponding to the CAI resolution. The off-nadir reflectance is measured simultaneously with BRDF values, for correction. We will summarize the radiometric study of the GOSAT lunar calibration compared with the vicarious calibration. In-flight coincident calibration activities will continue with GOSAT and OCO-2.

  18. Three Years of Atmospheric Infrared Sounder Radiometric Calibration Validation using Sea Surface Temperatures

    NASA Technical Reports Server (NTRS)

    Aumann, H. H.; Broberg, Steve; Elliott, Denis; Gaiser, Steve; Gregorich, Dave

    2006-01-01

    This paper evaluates the absolute accuracy and stability of the radiometric calibration of the Atmospheric Infrared Sounder (AIRS) by analyzing the difference between the brightness temperatures measured at 2616 cm(exp -1) and those calculated at the top of the atmosphere (TOA), using the Real-Time Global Sea Surface Temperature (RTGSST) for cloud-free night tropical oceans between +/- 30 degrees latitude. The TOA correction is based on radiative transfer. The analysis of the first 3 years of AIRS radiances verifies the absolute calibration at 2616 cm(exp -1) to better than 200 mK, with better than 16 mK/yr stability. The AIRS radiometric calibration uses an internal full aperture wedge blackbody with the National Institute of Standards and Technology (NIST) traceable prelaunch calibration coefficients. The calibration coefficients have been unchanged since launch. The analysis uses very tight cloud filtering, which selects about 7000 cloud-free tropical ocean spectra per day, about 0.5% of the data. The absolute accuracy and stability of the radiometry demonstrated at 2616 cm(sup -1) are direct consequences of the implementation of AIRS as a thermally controlled, cooled grating-array spectrometer and meticulous attention to details. Comparable radiometric performance is inferred from the AIRS design for all 2378 channels. AIRS performance sets the benchmark for what can be achieved with a state-of-the-art hyperspectral radiometer from polar orbit and what is expected from future hyperspectral sounders. AIRS was launched into a 705 km altitude polar orbit on NASA's Earth Observation System (EOS) Aqua spacecraft on 4 May 2002. AIRS covers the 3.7-15.4 micron region of the thermal infrared spectrum with a spectral resolution of nu/Delta nu = 1200 and has returned 3.7 million spectra of the upwelling radiance each day since the start of routine data gathering in September 2002.

  19. L5 TM radiometric recalibration procedure using the internal calibration trends from the NLAPS trending database

    USGS Publications Warehouse

    Chander, G.; Haque, Md. O.; Micijevic, E.; Barsi, J.A.

    2008-01-01

    From the Landsat program's inception in 1972 to the present, the earth science user community has benefited from a historical record of remotely sensed data. The multispectral data from the Landsat 5 (L5) Thematic Mapper (TM) sensor provide the backbone for this extensive archive. Historically, the radiometric calibration procedure for this imagery used the instrument's response to the Internal Calibrator (IC) on a scene-by-scene basis to determine the gain and offset for each detector. The IC system degraded with time causing radiometric calibration errors up to 20 percent. In May 2003 the National Landsat Archive Production System (NLAPS) was updated to use a gain model rather than the scene acquisition specific IC gains to calibrate TM data processed in the United States. Further modification of the gain model was performed in 2007. L5 TM data that were processed using IC prior to the calibration update do not benefit from the recent calibration revisions. A procedure has been developed to give users the ability to recalibrate their existing Level-1 products. The best recalibration results are obtained if the work order report that was originally included in the standard data product delivery is available. However, many users may not have the original work order report. In such cases, the IC gain look-up table that was generated using the radiometric gain trends recorded in the NLAPS database can be used for recalibration. This paper discusses the procedure to recalibrate L5 TM data when the work order report originally used in processing is not available. A companion paper discusses the generation of the NLAPS IC gain and bias look-up tables required to perform the recalibration.

  20. Radiometrically Terrain Corrected ALOS PALSAR Data Available from the Alaska Satellite Facility

    NASA Astrophysics Data System (ADS)

    Logan, T. A.; Nicoll, J.; Laurencelle, J.; Hogenson, K.; Gens, R.; Buechler, B.; Barton, B.; Shreve, W.; Stern, T.; Drew, L.; Guritz, R.

    2014-12-01

    The Alaska Satellite Facility Distributed Active Archive Data Center (ASF DAAC) now offers a suite of geometrically and radiometrically terrain corrected data products derived from ALOS PALSAR, processed using the Gamma Remote Sensing software package. Radiometric terrain correction (RTC) addresses two aspects of the effects of side-looking geometry of SAR imagery. First, the geometric distortions are corrected using the best digital elevation model available for a given region. Second, the radiometry is adjusted in the affected foreshortening and layover regions using the pixel-area integration approach for radiometric normalization. The RTC process provides improved backscatter estimates that can be used as input for applications such as the monitoring of deforestation, land-cover classification, and delineation of wet snow covered areas. RTC products are distributed at two resolutions. RT1 products with a pixel size of 12.5 m are generated from high-resolution and mid-resolution digital elevation models (DEMs). RT2 products are generated at a 30 m level for all available DEMs. Layover and shadow masks as well as incidence angle maps are available for both product resolutions. Products cover landmasses generally from 60 degrees northern latitude to 59 degrees southern latitude. An exception to the rule is the inclusion of all of North America. Excluded landmasses are Greenland, Iceland, Antarctica, and northern Eurasia. Since scientists are generally interested in quantitative measurements that are referenced to the ground, products are distributed in σ0 power. All RTC products are geocoded to the Universal Transverse Mercator (UTM) projection, provided in GIS ready GeoTIFF format and downloadable from the ASF DAAC.

  1. Whitecap lifetime stages from infrared imagery with implications for microwave radiometric measurements of whitecap fraction

    NASA Astrophysics Data System (ADS)

    Potter, Henry; Smith, Geoffrey B.; Snow, Charlotte M.; Dowgiallo, David J.; Bobak, Justin P.; Anguelova, Magdalena D.

    2015-11-01

    Quantifying active and residual whitecap fractions separately can improve parameterizations of air-sea fluxes associated with breaking waves. We use data from a multi-instrumental field campaign on Floating Instrument Platform (FLIP) to simultaneously capture the signatures of active and residual whitecaps at visible, infrared (IR), and microwave wavelengths using, respectively, video camera, mid-IR camera, and a radiometer at 10 GHz. We present results from processing and analyzing IR images and correlating this information with radiometric time series of brightness temperature at horizontal and vertical polarizations TBH and TBV. The results provide evidence that breaking crests and decaying foam appear in mid-IR as bright and dark pixels clearly distinguishing active from residual whitecaps. We quantify the durations of whitecap lifetime stages from the IR images and identify their corresponding signatures in TB time series. Results show that TBH and TBV vary in phase during the active and in antiphase during the residual whitecap stages. A methodology to distinguish active and residual whitecaps in radiometric time series without a priori IR information has been developed and verified with corresponding IR and video images. The method uses the degree of polarization P (the ratio between the sum and difference of TBV and TBH) to capture whitecaps as prominent spikes. The maximum and zero-crossing of the first derivative of P serve to identify the presence of active whitecaps, while the minimum of dP marks the transition from active to residual whitecap stage. The findings have implications for radiometric measurements of active and total whitecap fractions.

  2. The absolute radiometric calibration of Terra imaging sensors: MODIS, MISR, and ASTER

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, Jeffrey; Thome, Kurtis; Anderson, Nikolaus; Biggar, Stuart

    2014-10-01

    The Terra spacecraft contains five Earth-observation instruments, three of which are multispectral imaging sensors that complement each other in spectral and spatial coverage. The Moderate Resolution Imaging Spectroradiometer (MODIS) has 36 channels ranging from 0.4-14.4 μm, with spatial resolutions of 250, 500, and 1000 m. The Multi-angle Imaging SpectroRadiometer (MISR) uses individual imaging sensors to view the earth at nine discreet angles. Each radiometer has four channels in the visible and near infrared (VNIR), and the nadir-viewing camera has a spatial resolution of 275 m. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) was designed with fourteen bands ranging from 0.5-11.6 μm. It is the high-resolution sensor on Terra, with a spatial resolution of 15 m in the VNIR, and 30 m in the shortwave infrared (SWIR). This work describes the vicarious techniques used to perform the absolute radiometric calibration of MODIS, MISR, and ASTER in the solar-reflective region (0.4-2.5 μm). It includes the reflectance-based approach, which uses ground-based personnel to make in situ measurements during the time of overpass. It also includes more recent results that were obtained using the University of Arizona's automated Radiometric Calibration Test Site (RadCaTS) at Railroad Valley, Nevada. In addition to the absolute radiometric calibration of Terra sensors, RadCaTS is used to perform the cross comparison of MODIS, MISR, and ASTER with Landsat 7 ETM+ and Landsat 8 OLI.

  3. FPGA-based data processing module design of on-board radiometric calibration in visible/near infrared bands

    NASA Astrophysics Data System (ADS)

    Zhou, Guoqing; Li, Chenyang; Yue, Tao; Liu, Na; Jiang, Linjun; Sun, Yue; Li, Mingyan

    2015-12-01

    FPGA technology has long been applied to on-board radiometric calibration data processing however the integration of FPGA program is not good enough. For example, some sensors compressed remote sensing images and transferred to ground station to calculate the calibration coefficients. It will affect the timeliness of on-board radiometric calibration. This paper designs an integrated flow chart of on-board radiometric calibration. Building FPGA-based radiometric calibration data processing modules uses system generator. Thesis focuses on analyzing the calculation accuracy of FPGA-based two-point method and verifies the feasibility of this method. Calibration data was acquired by hardware platform which was built using integrating sphere, CMOS camera (canon 60d), ASD spectrometers and light filter (center wavelength: 690nm, bandwidth: 45nm). The platform can simulate single-band on-board radiometric calibration data acquisition in visible/near infrared band. Making an experiment of calibration coefficients calculation uses obtained data and FPGA modules. Experimental results show that: the camera linearity is above 99% meeting the experimental requirement. Compares with MATLAB the calculation accuracy of two-point method by FPGA are as follows: the error of gain value is 0.0053%; the error of offset value is 0.00038719%. Those results meet experimental accuracy requirement.

  4. PHASS99: A software program for retrieving and decoding the radiometric ages of igneous rocks from the international database IGBADAT

    NASA Astrophysics Data System (ADS)

    Al-Mishwat, Ali T.

    2016-05-01

    PHASS99 is a FORTRAN program designed to retrieve and decode radiometric and other physical age information of igneous rocks contained in the international database IGBADAT (Igneous Base Data File). In the database, ages are stored in a proprietary format using mnemonic representations. The program can handle up to 99 ages in an igneous rock specimen and caters to forty radiometric age systems. The radiometric age alphanumeric strings assigned to each specimen description in the database consist of four components: the numeric age and its exponential modifier, a four-character mnemonic method identification, a two-character mnemonic name of analysed material, and the reference number in the rock group bibliography vector. For each specimen, the program searches for radiometric age strings, extracts them, parses them, decodes the different age components, and converts them to high-level English equivalents. IGBADAT and similarly-structured files are used for input. The output includes three files: a flat raw ASCII text file containing retrieved radiometric age information, a generic spreadsheet-compatible file for data import to spreadsheets, and an error file. PHASS99 builds on the old program TSTPHA (Test Physical Age) decoder program and expands greatly its capabilities. PHASS99 is simple, user friendly, fast, efficient, and does not require users to have knowledge of programing.

  5. Study of spectral/radiometric characteristics of the Thematic Mapper for land use applications

    NASA Technical Reports Server (NTRS)

    Malila, W. A. (Principal Investigator); Metzler, M. D.

    1984-01-01

    Progress during the Environmental Research Institute of Michigan-ERIM's and 5 image data quality assessment program for the thematic mapper is described. Analyses of LANDSAT 5 TM radiometric characteristics were performed. Effects which had earlier been found in LANDSAT 4 TM data were found to be present in LANDSAT 5 data as well, including: (1) scan direction related signal droop; (2) scan correlated level shifts; and (3) low frequency coherent noise. Coincident LANDSAT 4 and 5 raw TM data were analyzed, and band by band relationships between the two sensors were derived. Earlier efforts which developed an information theoretic measure of multispectral information content were continued, comparing TM and MSS information content.

  6. Variations in in-flight absolute radiometric calibration. [satellite remote sensors

    NASA Technical Reports Server (NTRS)

    Slater, Philip N.

    1986-01-01

    Variations in the in-flight absolute radiometric calibration of the Coastal Zone Color Scanner and the Thematic Mapper (TM) are reviewed. At short wavelengths, the sensors show a gradual reduction in response, while in the mid-IR the TM shows oscillatory variations. One set of measurements made at White Sands, New Mexico shows anomalous results in TM bands 2 and 4. The results of a reflectance-based and a radiance-based calibration method at White Sands are described. An analysis of the radiance-based method shows the value of such measurements from helicopter altitudes for calibration.

  7. Evaluation of spatial, radiometric and spectral Thematic Mapper performance for coastal studies

    NASA Technical Reports Server (NTRS)

    Klemas, V.; Ackleson, S. G.; Hardisky, M. A.

    1985-01-01

    On 31 March 1983, the University of Delaware's Center for Remote Sensing initiated a study to evaluate the spatial, radiometric and spectral performance of the LANDSAT Thematic Mapper for coastal and estuarine studies. The investigation was supported by Contract NAS5-27580 from the NASA Goddard Space Flight Center. The research was divided into three major subprojects: (1) a comparison of LANDSAT TM to MSS imagery for detecting submerged aquatic vegetation in Chesapeake Bay; (2) remote sensing of submerged aquatic vegetation - a radiative transfer approach; and (3) remote sensing of coastal wetland biomass using Thematic Mapper wavebands.

  8. In-progress Absolute Radiometric Inflight Calibration of the LANDSAT-4 Sensors. [New Mexico

    NASA Technical Reports Server (NTRS)

    Castle, K. R.; Dinguirard, M.; Ezra, C. E.; Holm, R. G.; Jackson, R. D.; Kastner, C. J.; Palmer, J. M.; Savage, R.; Slater, P. N.

    1985-01-01

    Using selected instrumented areas at White Sands Missile Range, New Mexico as reference, radiometric calibration is to be effected on the sensors of LANDSAT 4, particularly the thematic mapper. Optical measurements made during a TM overpass are discussed. The radiances of selected large ground areas are measured in the spectral bandpasses of the TM; the total optical thickness of the atmosphere is measured in nine narrow spectral intervals. Ground truth in the form of reflectances collected for the alkalai flat region of gypsum and for the snow at White Sands is described.

  9. A Kalman Approach to Lunar Surface Navigation using Radiometric and Inertial Measurements

    NASA Technical Reports Server (NTRS)

    Chelmins, David T.; Welch, Bryan W.; Sands, O. Scott; Nguyen, Binh V.

    2009-01-01

    Future lunar missions supporting the NASA Vision for Space Exploration will rely on a surface navigation system to determine astronaut position, guide exploration, and return safely to the lunar habitat. In this report, we investigate one potential architecture for surface navigation, using an extended Kalman filter to integrate radiometric and inertial measurements. We present a possible infrastructure to support this technique, and we examine an approach to simulating navigational accuracy based on several different system configurations. The results show that position error can be reduced to 1 m after 5 min of processing, given two satellites, one surface communication terminal, and knowledge of the starting position to within 100 m.

  10. Radiometric traverse along the Yukon River from Fort Yukon to Ruby, Alaska, 1949

    USGS Publications Warehouse

    White, Max G.; Stevens, John M.; Matzko, John J.

    1956-01-01

    In 1949, a radiometric traverse was made of rocks exposed along the banks of and near the Yukon River about Fort Yukon to Ruby, Alaska. Granitic rocks of Tertiary age and of Devonian or Carboniferous age and sandstone beds of Cretaceous age gave the highest readings obtained in the field. Other rock types examined were greenstone of Devonian or Carboniferous age and metamorphic rocks of Devonian and pre-Devonian age, sedimentary rocks, and liginite of Tertiary age, and alluvial deposits of Quaternary age. The most radioactive sample, from Melozitna River canyon, contained only 0.017 percent equivalent uranium.

  11. Radiometric assay of ghrelin hydrolase activity and 3H-ghrelin distribution into mouse tissues.

    PubMed

    Chen, Vicky Ping; Gao, Yang; Geng, Liyi; Brimijoin, Stephen

    2015-12-15

    A high-throughput radiometric assay was developed to characterize enzymatic hydrolysis of ghrelin and to track the peptide's fate in vivo. The assay is based on solvent partitioning of [(3)H]-octanoic acid liberated from [(3)H]-octanoyl ghrelin during enzymatic hydrolysis. This simple and cost-effective method facilitates kinetic analysis of ghrelin hydrolase activity of native and mutated butyrylcholinesterases or carboxylesterases from multiple species. In addition, the assay's high sensitivity facilitates ready evaluation of ghrelin's pharmacokinetics and tissue distribution in mice after i.v. bolus administration of radiolabeled peptide. PMID:26514871

  12. PRELIMINARY EVALUATION OF LANDSAT-4 THEMATIC MAPPER DATA FOR THEIR GEOMETRIC AND RADIOMETRIC ACCURACIES.

    USGS Publications Warehouse

    Podwysoki, M.H.; Falcone, N.; Bender, L.U.; Jones, O.D.

    1985-01-01

    This report describes results of some preliminary analyses of Landsat-4 Thematic Mapper data for the NASA Landsat Image Quality Analysis program. The work is being done under interagency agreement S-12407-C between the U. S. Geological Survey and NASA-Goddard Space Flight Center. Landsat-4 TM scenes for Washington, D. C. Macon, Georgia (40050-15333, September 4, 1982) and Cape Canaveral, Florida have been examined to determine their geometric and radiometric accuracy. In addition, parts of these scenes are also being analyzed to determine the ability to identify specific rock types with the added near-infrared TM bands.

  13. Earth Return Navigation Analysis for Manned Spacecraft Using Optical and Radiometric Measurements

    NASA Technical Reports Server (NTRS)

    Abrahamson, Matthew J.; Ely, Todd A.

    2010-01-01

    Future manned space missions will travel beyond low Earth orbit with more stringent navigation requirements and fewer navigation resources than used for the Apollo Program of the 1960s. A study has been performed to assess radiometric and optical tracking capabilities necessary to meet nominal and contingency Earth entry flight path angle requirements. Results indicate that 3 tracking stations will be insufficient for meeting nominal entry requirements, while the performance of a 6 station architecture is dependent on the entry geometry. Optical tracking results indicate that a narrow-angle camera is required for satisfying contingency Earth return requirements.

  14. High speed lookup table approach to radiometric calibration of multispectral image data

    NASA Technical Reports Server (NTRS)

    Kelly, W. L., IV; Meredith, B. D.; Howle, W. M.

    1980-01-01

    A concept for performing radiometric correction of multispectral image data onboard a spacecraft at very high data rates is presented and demonstrated. This concept utilized a lookup table approach, implemented in hardware, to convert the raw sensor data into the desired corrected output data. The digital lookup table memory was interfaced to a microprocessor to allow the data correction function to be completely programmable. Sensor data was processed with this approach at rates equal to the access time of the lookup table memory. This concept offers flexible high speed data processing for a wide range of applications and will benefit from the continuing improvements in performance of digital memories.

  15. Algorithms for Relative Radiometric Correction in Earth Observing Systems Resource-P and Canopus-V

    NASA Astrophysics Data System (ADS)

    Zenin, V. A.; Eremeev, V. V.; Kuznetcov, A. E.

    2016-06-01

    The present paper has considered two algorithms of the relative radiometric correction of information obtained from a multimatrix imagery instrument of the spacecraft "Resource-P" and frame imagery systems of the spacecraft "Canopus-V". The first algorithm is intended for elimination of vertical stripes on the image that are caused by difference in transfer characteristics of CCD matrices and CCD detectors. Correction coefficients are determined on the basis of analysis of images that are homogeneous by brightness. The second algorithm ensures an acquisition of microframes homogeneous by brightness from which seamless images of the Earth surface are synthesized. Examples of practical usage of the developed algorithms are mentioned.

  16. The effect of spatial, spectral and radiometric factors on classification accuracy using thematic mapper data

    NASA Technical Reports Server (NTRS)

    Wrigley, R. C.; Acevedo, W.; Alexander, D.; Buis, J.; Card, D.

    1984-01-01

    An experiment of a factorial design was conducted to test the effects on classification accuracy of land cover types due to the improved spatial, spectral and radiometric characteristics of the Thematic Mapper (TM) in comparison to the Multispectral Scanner (MSS). High altitude aircraft scanner data from the Airborne Thematic Mapper instrument was acquired over central California in August, 1983 and used to simulate Thematic Mapper data as well as all combinations of the three characteristics for eight data sets in all. Results for the training sites (field center pixels) showed better classification accuracies for MSS spatial resolution, TM spectral bands and TM radiometry in order of importance.

  17. Study on spectral/radiometric characteristics of the Thematic Mapper for land use applications

    NASA Technical Reports Server (NTRS)

    Malila, W. A. (Principal Investigator); Metzler, M. D.

    1984-01-01

    Progress under the LANDSAT-4 and 5 Image Data Quality Assessment program for the Thematic Mapper is described. An initial screening of LANDSAT-5 data is performed. Tools are developed to allow access to TIPS-format data. Analysis of scan direction related signal droop is resumed with detailed analysis of nighttime data. A new mathematical model is developed to describe the effect. Coherent noise of a lower frequency than previously reported is discovered and analyzed. Coincident LANDSAT-4 TM and MSS data are analyzed to improve understanding of radiometric relationships between similar wavebands in the two sensors.

  18. Titan Density Reconstruction Using Radiometric and Cassini Attitude Control Flight Data

    NASA Technical Reports Server (NTRS)

    Andrade, Luis G., Jr.; Burk, Thomas A.

    2015-01-01

    This paper compares three different methods of Titan atmospheric density reconstruction for the Titan 87 Cassini flyby. T87 was a unique flyby that provided independent Doppler radiometric measurements on the ground throughout the flyby including at Titan closest approach. At the same time, the onboard accelerometer provided an independent estimate of atmospheric drag force and density during the flyby. These results are compared with the normal method of reconstructing atmospheric density using thruster on-time and angular momentum accumulation. Differences between the estimates are analyzed and a possible explanation for the differences is evaluated.

  19. Direct Radiometric Observations of the Water Vapor Greenhouse Effect Over the Equatorial Pacific Ocean

    PubMed

    Valero; Collins; Pilewskie; Bucholtz; Flatau

    1997-03-21

    Airborne radiometric measurements were used to determine tropospheric profiles of the clear sky greenhouse effect. At sea surface temperatures (SSTs) larger than 300 kelvin, the clear sky water vapor greenhouse effect was found to increase with SST at a rate of 13 to 15 watts per square meter per kelvin. Satellite measurements of infrared radiances and SSTs indicate that almost 52 percent of the tropical oceans between 20°N and 20°S are affected during all seasons. Current general circulation models suggest that the increase in the clear sky water vapor greenhouse effect with SST may have climatic effects on a planetary scale. PMID:9065397

  20. Analysis of radiometric signal in sedimentating suspension flow in open channel

    NASA Astrophysics Data System (ADS)

    Zych, Marcin; Hanus, Robert; Petryka, Leszek; Świsulski, Dariusz; Doktor, Marek; Mastej, Wojciech

    2015-05-01

    The article discusses issues related to the estimation of the sedimentating solid particles average flow velocity in an open channel using radiometric methods. Due to the composition of the compound, which formed water and diatomite, received data have a very weak signal to noise ratio. In the process analysis the known determining of the solid phase transportation time delay the classical cross-correlation function is the most reliable method. The use of advanced frequency analysis based on mutual spectral density function and wavelet transform of recorded signals allows a reduction of the noise contribution.

  1. The Future Spaceborne Hyperspectral Imager Enmap: its In-Flight Radiometric and Geometric Calibration Concept

    NASA Astrophysics Data System (ADS)

    Schneider, M.; Müller, R.; Krawzcyk, H.; Bachmann, M.; Storch, T.; Mogulsky, V.; Hofer, S.

    2012-07-01

    The German Aerospace Center DLR - namely the Earth Observation Center EOC and the German Space Operations Center GSOC - is responsible for the establishment of the ground segment of the future German hyperspectral satellite mission EnMAP (Environmental Mapping and Analysis Program). The Earth Observation Center has long lasting experiences with air- and spaceborne acquisition, processing, and analysis of hyperspectral image data. In the first part of this paper, an overview of the radiometric in-flight calibration concept including dark value measurements, deep space measurements, internal lamps measurements and sun measurements is presented. Complemented by pre-launch calibration and characterization these analyses will deliver a detailed and quantitative assessment of possible changes of spectral and radiometric characteristics of the hyperspectral instrument, e.g. due to degradation of single elements. A geometric accuracy of 100 m, which will be improved to 30 m with respect to a used reference image, if it exists, will be achieved by ground processing. Therfore, and for the required co-registration accuracy between SWIR and VNIR channels, additional to the radiometric calibration, also a geometric calibration is necessary. In the second part of this paper, the concept of the geometric calibration is presented in detail. The geometric processing of EnMAP scenes will be based on laboratory calibration results. During repeated passes over selected calibration areas images will be acquired. The update of geometric camera model parameters will be done by an adjustment using ground control points, which will be extracted by automatic image matching. In the adjustment, the improvements of the attitude angles (boresight angles), the improvements of the interior orientation (view vector) and the improvements of the position data are estimated. In this paper, the improvement of the boresight angles is presented in detail as an example. The other values and combinations

  2. China radiometric calibration sites ground-based automatic observing systems for CAL/VAL

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Li, Xin; Rong, Zhiguo; Zhang, Lijun; Hu, Xiuqing; Ba, Xiutian

    2015-10-01

    A brand-new field observing station has been built up in the China radiometric calibration sites (CRCS) of Dunhuang Gobi for CAL/VAL, include house, observing field, power supply, tower crane, et al. Many automatic observation instruments designed and manufactured by Anhui Institute of Optics and Fine Mechanical Chinese Academy of Sciences were deployed in CRCS Dunhuang Site and introduced deeply in this paper. Followed with the finishing of the basic constructions of the field observing station, it will be an open field test and exchange platform for sharing of test data, research and infrastructure, promote exchanges and cooperation between the relevant disciplines and units.

  3. The Human Serum Metabolome

    PubMed Central

    Psychogios, Nikolaos; Hau, David D.; Peng, Jun; Guo, An Chi; Mandal, Rupasri; Bouatra, Souhaila; Sinelnikov, Igor; Krishnamurthy, Ramanarayan; Eisner, Roman; Gautam, Bijaya; Young, Nelson; Xia, Jianguo; Knox, Craig; Dong, Edison; Huang, Paul; Hollander, Zsuzsanna; Pedersen, Theresa L.; Smith, Steven R.; Bamforth, Fiona; Greiner, Russ; McManus, Bruce; Newman, John W.; Goodfriend, Theodore; Wishart, David S.

    2011-01-01

    Continuing improvements in analytical technology along with an increased interest in performing comprehensive, quantitative metabolic profiling, is leading to increased interest pressures within the metabolomics community to develop centralized metabolite reference resources for certain clinically important biofluids, such as cerebrospinal fluid, urine and blood. As part of an ongoing effort to systematically characterize the human metabolome through the Human Metabolome Project, we have undertaken the task of characterizing the human serum metabolome. In doing so, we have combined targeted and non-targeted NMR, GC-MS and LC-MS methods with computer-aided literature mining to identify and quantify a comprehensive, if not absolutely complete, set of metabolites commonly detected and quantified (with today's technology) in the human serum metabolome. Our use of multiple metabolomics platforms and technologies allowed us to substantially enhance the level of metabolome coverage while critically assessing the relative strengths and weaknesses of these platforms or technologies. Tables containing the complete set of 4229 confirmed and highly probable human serum compounds, their concentrations, related literature references and links to their known disease associations are freely available at http://www.serummetabolome.ca. PMID:21359215

  4. The First SIMBIOS Radiometric Intercomparison (SIMRIC-1), April-September 2001

    NASA Technical Reports Server (NTRS)

    Meister, Gerhard; Abel, Peter; McClain, Charles; Barnes, Robert; Fargion, Giulietta; Cooper, John; Davis, Curtiss; Korwan, Daniel; Godin, Mike; Maffione, Robert

    2002-01-01

    This report describes the first SIMBIOS (Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies) Radiometric Intercomparison (SIMRIC-1). The purpose of the SIMRIC-1 is to ensure a common radiometric scale of the calibration facilities that are engaged in calibrating in situ radiometers used for ocean color related research and to document the calibration procedures and protocols. SIMBIOS staff visited the seven participating laboratories for at least two days each. The SeaWiFS Transfer Radiometer SXR-II measured the calibration radiances produced in the laboratories. The measured radiances were compared with the radiances expected by the laboratories. Typically, the measured radiances were higher than the expected radiances by 0 to 2%. This level of agreement is satisfactory. Several issues were identified, where the calibration protocols need to be improved, especially the reflectance calibration of the reference plaques and the distance correction when using the irradiance standards at distances greater than the 50 cm. The responsivity of the SXR-II changed between 0.3% (channel 6) and 1.6% (channel 2) from December 2000 to December 2001. Monitoring the SXR-II with a portable light source showed a linear drift of the calibration, except for channel 1, where a 2% drop occurred in summer.

  5. Radiometric, SEM and XRD investigation of the Chituc black sands, southern Danube Delta, Romania.

    PubMed

    Margineanu, R M; Blebea-Apostu, Ana-Maria; Celarel, Aurelia; Gomoiu, Claudia-Mariana; Costea, C; Dumitras, Delia; Ion, Adriana; Duliu, O G

    2014-12-01

    The black sand of the Chituc marine sand bank, northern of the city of Navodari (Romania), presents anomalous high radioactivity. Field measurements recorded in some places dose rate up to 200 nSv/h, significantly overpassing the average value of 44 ± 20 nSv/h along the entire Southern sector of Romanian Black Sea shore. Gamma ray spectrometry performed on both Slanic-Prahova Underground Low Background Laboratory and Geological Institute of Romania Radiometric Facilities showed with clarity the dominance of (228)Ac radioisotope in the 50 microns fraction together with the (226)Ra and traces of (40)K. No significant amount of anthropogenic (137)Cs was identified. Based on radiometric as well as on SEM-EDAX and XRD determinations we come to the conclusion that the evidenced radioactivity could be attributed to both uranium and thorium series in the zircon and monazite fractions and to a lesser extent to potassium in the feldspars. PMID:25181034

  6. [In-flight absolute radiometric calibration of UAV hyperspectral camera and its validation analysis].

    PubMed

    Gou, Zhi-yang; Yan, Lei; Chen, Wei; Jing, Xin; Yin, Zhong-yi; Duan, Yi-ni

    2012-02-01

    With the data in Urad Front Banner, Inner Mongolia on November 14th, 2010, hyper-spectral camera on UAV was calibrated adopting reflectance-based method. During the in-flight absolute radiometric calibration, 6 hyper-spectral radiometric gray-scale targets were arranged in the validation field. These targets' reflectances are 4.5%, 20%, 30%, 40%, 50% and 60% separately. To validate the calibration result, four extra hyper-spectral targets with sharp-edge spectrum were arranged to simulate the reflection and absorption peaks in natural objectives. With these peaks, the apparent radiance calculated by radiation transfer model and that calculated through calibration coefficients are much different. The result shows that in the first 15 bands (blue bands), errors are somewhat huge due to the noises of equipment. In the rest bands with quite even spectrum, the errors are small, most of which are less than 10%. For those bands with sharp changes in spectral curves, the errors are quite considerable, varying from 10% to 25%. PMID:22512184

  7. Thermal Infrared Radiometric Calibration of the Entire Landsat 4, 5, and 7 Archive (1982-2010)

    NASA Technical Reports Server (NTRS)

    Schott, John R.; Hook, Simon J.; Barsi, Julia A.; Markham, Brian L.; Miller, Jonathan; Padula, Francis P.; Raqueno, Nina G.

    2012-01-01

    Landsat's continuing record of the thermal state of the earth's surface represents the only long term (1982 to the present) global record with spatial scales appropriate for human scale studies (i.e., tens of meters). Temperature drives many of the physical and biological processes that impact the global and local environment. As our knowledge of, and interest in, the role of temperature on these processes have grown, the value of Landsat data to monitor trends and process has also grown. The value of the Landsat thermal data archive will continue to grow as we develop more effective ways to study the long term processes and trends affecting the planet. However, in order to take proper advantage of the thermal data, we need to be able to convert the data to surface temperatures. A critical step in this process is to have the entire archive completely and consistently calibrated into absolute radiance so that it can be atmospherically compensated to surface leaving radiance and then to surface radiometric temperature. This paper addresses the methods and procedures that have been used to perform the radiometric calibration of the earliest sizable thermal data set in the archive (Landsat 4 data). The completion of this effort along with the updated calibration of the earlier (1985 1999) Landsat 5 data, also reported here, concludes a comprehensive calibration of the Landsat thermal archive of data from 1982 to the present

  8. Extreme Ultraviolet Variability Experiment (EVE) Multiple EUV Grating Spectrographs (MEGS): Radiometric Calibrations and Results

    NASA Astrophysics Data System (ADS)

    Hock, R. A.; Chamberlin, P. C.; Woods, T. N.; Crotser, D.; Eparvier, F. G.; Woodraska, D. L.; Woods, E. C.

    2012-01-01

    The NASA Solar Dynamics Observatory (SDO), scheduled for launch in early 2010, incorporates a suite of instruments including the Extreme Ultraviolet Variability Experiment (EVE). EVE has multiple instruments including the Multiple Extreme ultraviolet Grating Spectrographs (MEGS) A, B, and P instruments, the Solar Aspect Monitor (SAM), and the Extreme ultraviolet SpectroPhotometer (ESP). The radiometric calibration of EVE, necessary to convert the instrument counts to physical units, was performed at the National Institute of Standards and Technology (NIST) Synchrotron Ultraviolet Radiation Facility (SURF III) located in Gaithersburg, Maryland. This paper presents the results and derived accuracy of this radiometric calibration for the MEGS A, B, P, and SAM instruments, while the calibration of the ESP instrument is addressed by Didkovsky et al. ( Solar Phys., 2010, doi:10.1007/s11207-009-9485-8). In addition, solar measurements that were taken on 14 April 2008, during the NASA 36.240 sounding-rocket flight, are shown for the prototype EVE instruments.

  9. The moon as a radiometric reference source for on-orbit sensor stability calibration

    USGS Publications Warehouse

    Stone, T.C.

    2009-01-01

    The wealth of data generated by the world's Earth-observing satellites, now spanning decades, allows the construction of long-term climate records. A key consideration for detecting climate trends is precise quantification of temporal changes in sensor calibration on-orbit. For radiometer instruments in the solar reflectance wavelength range (near-UV to shortwave-IR), the Moon can be viewed as a solar diffuser with exceptional stability properties. A model for the lunar spectral irradiance that predicts the geometric variations in the Moon's brightness with ???1% precision has been developed at the U.S. Geological Survey in Flagstaff, AZ. Lunar model results corresponding to a series of Moon observations taken by an instrument can be used to stabilize sensor calibration with sub-percent per year precision, as demonstrated by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). The inherent stability of the Moon and the operational model to utilize the lunar irradiance quantity provide the Moon as a reference source for monitoring radiometric calibration in orbit. This represents an important capability for detecting terrestrial climate change from space-based radiometric measurements.

  10. Assessment of the short-term radiometric stability between Terra MODIS and Landsat 7 ETM+ sensors

    USGS Publications Warehouse

    Choi, Taeyoung; Xiong, Xiaoxiong; Chander, Gyanesh; Angal, A.

    2009-01-01

    Short-term radiometric stability was evaluated using continuous ETM+ scenes within a single orbit (contact period) and the corresponding MODIS scenes for the four matching solar reflective visible and near-infrared (VNIR) band pairs between the two sensors. The near-simultaneous earth observations were limited by the smaller swath size of ETM+ (183 km) compared to MODIS (2330 km). Two sets of continuous granules for Terra MODIS and Landsat 7 ETM+ were selected and mosaicked based on pixel geolocation information for noncloudy pixels over the African continent. The matching pixel pairs were resampled from a fine to a coarse pixel resolution, and the at-sensor spectral radiance values for a wide dynamic range of the sensors were compared and analyzed, covering various surface types. The following study focuses on radiometric stability analysis from the VNIR band-pairs of ETM+ and MODIS. The Libya-4 desert target was included in the path of this continuous orbit, which served as a verification point between the short-term and the long-term trending results from previous studies. MODTRAN at-sensor spectral radiance simulation is included for a representative desert surface type to evaluate the consistency of the results.

  11. Re-evaluation of pulsed photothermal radiometric profiling in samples with spectrally varied infrared absorption coefficient.

    PubMed

    Majaron, Boris; Milanic, Matija

    2007-02-21

    Spectral variation of the sample absorption coefficient in mid-infrared (muIR) demands caution in photothermal radiometric measurements, because a constant muIR is regularly assumed in inverse analysis of the acquired signals. Adverse effects of such approximation were recently demonstrated in numerical simulations of pulsed photothermal radiometric (PPTR) temperature profiling in soft biological tissues, utilizing a general-purpose optimization code in the reconstruction process. We present here an original reconstruction code, which combines a conjugate gradient minimization algorithm with non-negativity constraint to the sought temperature vector. For the same test examples as in the former report (hyper-Gaussian temperature profiles, InSb detector with 3-5 microm acquisition band, signal-to-noise ratio SNR=300) we obtain markedly improved reconstruction results, both when using a constant value mueff and when the spectral variation muIR(lambda) is accounted for in the analysis. By comparing the results, we find that the former approach introduces observable artefacts, especially in the superficial part of the profile (z<100 microm). However, the artefacts are much less severe than previously reported and are almost absent in the case of a deeper, single-lobed test profile. We demonstrate that the observed artefacts do not result from sub-optimal selection of mueff, and that they vary with specific realizations of white noise added to the simulated signals. The same holds also for a two-lobed test profile. PMID:17264372

  12. Real-Time EDL Navigation Performance Using Spacecraft to Spacecraft Radiometric Data

    NASA Technical Reports Server (NTRS)

    Burkhart, P. Daniel; Ely, Todd; Duncan, Courtney; Lightsey, Glenn; Campbell, Todd; Mogensen, Andy

    2006-01-01

    A two-year task sponsored by NASA's Mars Technology Program's Advanced Entry, Descent and Landing (EDL) work area includes investigation of improvements to EDL navigation by processing spacecraft-to-spacecraft radiometric data. Spacecraft-to-spacecraft navigation will take advantage of the UHF link between two spacecraft (i.e. to an orbiter from an approaching lander for EDL telemetry relay) to build radiometric data, specifically the velocity between the two spacecraft along the radio beam, that are processed to determine position and velocity in real time. The improved onboard state knowledge provided by spacecraft-to-spacecraft navigation will improve the performance of entry guidance by providing a more accurate state estimate and ultimately reduce the landed position error. A previous paper documented the progress of the first year of this task, including the spacecraft definitions, selection and documentation of the required algorithms and analysis results used to define the algorithm set. The final year of this task is reported here. Topics include modifications to the previously selected algorithm set for implementation, and performance of the implemented algorithms in a stand-alone filter, on an emulator of the target processor and finally on a breadboard processing unit.

  13. A multi-frequency radiometric measurement of soil moisture content over bare and vegetated fields

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Schmugge, T. J.; Mcmurtrey, J. E., III; Gould, W. I.; Glazar, W. S.; Fuchs, J. E. (Principal Investigator)

    1981-01-01

    A USDA Beltsville Agricultural Research Center site was used for an experiment in which soil moisture remote sensing over bare, grass, and alfalfa fields was conducted over a three-month period using 0.6 GHz, 1.4 GHz, and 10.6 GHz Dicke-type microwave radiometers mounted on mobile towers. Ground truth soil moisture content and ambient air and sil temperatures were obtained concurrently with the radiometric measurements. Biomass of the vegetation cover was sampled about once a week. Soil density for each of the three fields was measured several times during the course of the experiment. Results of the radiometric masurements confirm the frequency dependence of moisture sensing sensitivity reduction reported earlier. Observations over the bare, wet field show that the measured brightness temperature is lowest at 5.0 GHz and highest of 0.6 GHz frequency, a result contrary to expectation based on the estimated dielectric permittivity of soil water mixtures and current radiative transfer model in that frequency range.

  14. Simulations of three-dimensional radiometric imaging of extended sources in a security screening portal

    NASA Astrophysics Data System (ADS)

    Salmon, Neil A.; Bowring, Nick

    2015-10-01

    This paper investigates by simulation the use of the three-dimensional aperture synthesis imaging technique to image three-dimensional extended sources. Software was written to access the three-dimensional information from computer graphics models in the formats of *.dxf and *.3ds and use these to generate synthetic cross-correlations, as if they would have been generated by an aperture synthesis antenna/receiver array measuring the radiometric emission from the three-dimensional object. A three-dimensional (near-field) aperture synthesis imaging algorithm generates [1] a voxel image of the three-dimensional object. Images created from a sphere indicate faithful reproduction about a single phase centre when the radius of the sphere is less than the Fresnel scale. However, for larger spheres, definition in the threedimensional imagery suffers and a phenomenon, referred to in this paper as Fresnel noise, appears in the image. Images of objects larger than the Fresnel scale can be created by having multiple smaller images, each having a size approximately of the Fresnel scale and centred on separate phase centres. Using the software to generate threedimensional imagery of a person, to demonstrate capabilities for portal security screening, indicates the technique works to first order. Improvements are needed in the software to improve the spatial sampling of the radiometric fields from the three-dimensional objects and implement a volumetric image mosaicking technique to remove the Fresnel noise.

  15. Analysis of aerosol properties derived from sun photometer and lidar over Dunhuang radiometric calibration site

    NASA Astrophysics Data System (ADS)

    Chen, Lin; Jing, Yingying; Zhang, Peng; Hu, Xiuqing

    2016-05-01

    Duhuang site has been selected as China Radiation Calibration Site (CRCS) for Remote Sensing Satellite Sensors since 1996. With the economic development of Dunhuang city, the ambient of the radiation calibration field has changed in recent years. Taking into account the key role of aerosol in radiometric calibration, it is essential to investigate the aerosol optical properties over Dunhuang radiometric calibration site. In this paper, the CIMEL sun photometer (CE-318) and Mie-scattering Lidar are simultaneously used to measure aerosol optical properties in Dunhuang site. Data from aerosol-bands of sun photometer are used in a Langley method to determine spectral optical depths of aerosol. And Lidar is utilized to obtain information of vertical profile and integrated aerosol optical depths at different heights. The results showed that the aerosol optical depth at 500 nm wavelength during the in-situ measurement campaigns varied from 0.1 to 0.3 in Dunhuang site. And the observation results also indicated that high aerosol concentration layer mostly located at the height of about 2~4 km. These results implies that the aerosol concentration of atmosphere in Dunhuang was relatively small and suitable for in-flight calibration for remote sensing satellite sensors.

  16. Radiometric calibration method for large aperture infrared system with broad dynamic range.

    PubMed

    Sun, Zhiyuan; Chang, Songtao; Zhu, Wei

    2015-05-20

    Infrared radiometric measurements can acquire important data for missile defense systems. When observation is carried out by ground-based infrared systems, a missile is characterized by long distance, small size, and large variation of radiance. Therefore, the infrared systems should be manufactured with a larger aperture to enhance detection ability and calibrated at a broader dynamic range to extend measurable radiance. Nevertheless, the frequently used calibration methods demand an extended-area blackbody with broad dynamic range or a huge collimator for filling the system's field stop, which would greatly increase manufacturing costs and difficulties. To overcome this restriction, a calibration method based on amendment of inner and outer calibration is proposed. First, the principles and procedures of this method are introduced. Then, a shifting strategy of infrared systems for measuring targets with large fluctuations of infrared radiance is put forward. Finally, several experiments are performed on a shortwave infrared system with Φ400  mm aperture. The results indicate that the proposed method cannot only ensure accuracy of calibration but have the advantage of low cost, low power, and high motility. Hence, it is an effective radiometric calibration method in the outfield. PMID:26192499

  17. Use of Radiometrically Calibrated Flat-Plate Calibrators in Calibration of Radiation Thermometers

    NASA Astrophysics Data System (ADS)

    Cárdenas-García, D.; Méndez-Lango, E.

    2015-08-01

    Most commonly used, low-temperature, infrared thermometers have large fields of view sizes that make them difficult to be calibrated with narrow aperture blackbodies. Flat-plate calibrators with large emitting surfaces have been proposed for calibrating these infrared thermometers. Because the emissivity of the flat plate is not unity, its radiance temperature is wavelength dependent. For calibration, the wavelength pass band of the device under test should match that of the reference infrared thermometer. If the device under test and reference radiometer have different pass bands, then it is possible to calculate the corresponding correction if the emissivity of the flat plate is known. For example, a correction of at is required when calibrating a infrared thermometer with a "" radiometrically calibrated flat-plate calibrator. A method is described for using a radiometrically calibrated flat-plate calibrator that covers both cases of match and mismatch working wavelength ranges of a reference infrared thermometer and infrared thermometers to be calibrated with the flat-plate calibrator. Also, an application example is included in this paper.

  18. A preliminary evaluation of LANDSAT-4 thematic mapper data for their geometric and radiometric accuracies

    NASA Technical Reports Server (NTRS)

    Podwysocki, M. H.; Bender, L. U.; Falcone, N.; Jones, O. D.

    1983-01-01

    Some LANDSAT thematic mapper data collected over the eastern United States were analyzed for their whole scene geometric accuracy, band to band registration and radiometric accuracy. Band ratio images were created for a part of one scene in order to assess the capability of mapping geologic units with contrasting spectral properties. Systematic errors were found in the geometric accuracy of whole scenes, part of which were attributable to the film writing device used to record the images to film. Band to band registration showed that bands 1 through 4 were registered to within one pixel. Likewise, bands 5 and 7 also were registered to within one pixel. However, bands 5 and 7 were misregistered with bands 1 through 4 by 1 to 2 pixels. Band 6 was misregistered by 4 pixels to bands 1 through 4. Radiometric analysis indicated two kinds of banding, a modulo-16 stripping and an alternate light dark group of 16 scanlines. A color ratio composite image consisting of TM band ratios 3/4, 5/2, and 5/7 showed limonitic clay rich soils, limonitic clay poor soils, and nonlimonitic materials as distinctly different colors on the image.

  19. Development of radiometric system models for performance comparison of proposed instruments

    NASA Astrophysics Data System (ADS)

    Pavri, Betina E.; Bearman, Gregory H.; Margolis, Jack S.; Moynihan, Philip I.; Liu, Karen Y.

    1999-01-01

    Radiometric models have been used to optimize instrument design or evaluate impacts of changes to the design during integration and test. Tradeoffs such as spectral and spatial resolution, telescope and spectrometer temperature, aperture, f/No., integration time, optics and filter transmissions, and so forth can be quickly changed to evaluate changes to the signal/noise ratio or other performance metrics. An alternative use of such models is to identify promising instrument proposals for further study. A series of models were constructed to evaluate general instrument designs as an illustration of this process. These models included two grating spectrometers and a spatially modulated interferometer. All were given a common set of radiometric inputs and telescope optical prescription. Result of the modeling illustrate the performance differences between instrument types, although signal/noise predictions should be evaluated along with other parameters such as manufacturability, precision of calibration, and so forth. Such modeling allows instrument developers to demonstrate to potential customers improvements in their instruments, and the advantages of their product over other instruments for a specific application. If a common set of inputs is used for the different instrument models, this technique gives customers one metric with which to evaluate the disparate proposals.

  20. A Comprehensive Paleomagnetic Study on Radiometrically Dated Late Cretaceous Lava Flows from Jalisco Block (Western Mexico)

    NASA Astrophysics Data System (ADS)

    Rosas-Elguera, J.; Cervantes, M. A.; Gogichaishvili, A.; Morales, J.

    2014-12-01

    Western and central Mexico is segmented by several regional structural systems that bound crustal blocs. Paleomagnetic data from the western and eastern Trans Mexican Volcanic Belt as well as from adjacent terrains are still scarce which limits analyses of the both local and regional-scale tectonic evolution. A combined radiometric and paleomagnetic survey performed on late Cretaceous lava flows demonstrate that vertical-axis rotations characterize the paleotectonic evolution of western-central Mexico. The characteristic paleomagnetic directions determined in this study may be considered of primary (thermoremanent) origin. Multicomponent demagnetization plots were observed in some cases. In general, the polarity obtained for the flows studied is consistent with their stratigraphic position and with the radiometric age determination. The mean inclination is in reasonably good agreement with the expected inclination for the Late Creataceous, as derived from reference poles given by Besse and Courtillot (2002) for the North American craton. The declination, however, is quite different from that expected, which suggests a possible counterclockwise tectonic rotation of at least 12º. Aceptable palointensity determinations were obtained for only eleven individual samples from two basaltic lava flows. The mean virtual dipole moment (VDM) obtained in this study is 4.2 ± 1.2 _ 1022 A m2, which is almost half than the present geomagnetic field strength.

  1. Initial On-Orbit Radiometric Calibration of the Suomi NPP VIIRS Reflective Solar Bands

    NASA Technical Reports Server (NTRS)

    Lei, Ning; Wang, Zhipeng; Fulbright, Jon; Lee, Shihyan; McIntire, Jeff; Chiang, Vincent; Xiong, Jack

    2012-01-01

    The on-orbit radiometric response calibration of the VISible/Near InfraRed (VISNIR) and the Short-Wave InfraRed (SWIR) bands of the Visible/Infrared Imager/Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership (NPP) satellite is carried out through a Solar Diffuser (SD). The transmittance of the SD screen and the SD's Bidirectional Reflectance Distribution Function (BRDF) are measured before launch and tabulated, allowing the VIIRS sensor aperture spectral radiance to be accurately determined. The radiometric response of a detector is described by a quadratic polynomial of the detector?s digital number (dn). The coefficients were determined before launch. Once on orbit, the coefficients are assumed to change by a common factor: the F-factor. The radiance scattered from the SD allows the determination of the F-factor. In this Proceeding, we describe the methodology and the associated algorithms in the determination of the F-factors and discuss the results.

  2. On-orbit radiometric performance characterization of S-NPP VIIRS reflective solar bands

    NASA Astrophysics Data System (ADS)

    Uprety, Sirish; Blonski, Slawomir; Cao, Changyong

    2016-05-01

    It has been nearly four years that the S-NPP was launched. In an effort to improve the VIIRS calibration, VIIRS has undergone a number of major look up table updates during this period. RSB bands such as M1 through M3 suggested higher solar diffuser degradation rate. Similarly, for higher wavelengths, even though the solar diffuser degradation is much smaller and even negligible for SWIR bands, bands such as M7 suffer from major degradation due to RTA throughput degradation. Even though the solar diffuser and mirror degradation is well characterized, the data quality needs to be independently validated to ensure that data are well within the specification. We have used on-orbit calibration/validation techniques such as extended SNOs to estimate the bias of these bands and quantify the radiometric performance since launch. Assuming MODIS as a standard reference, intercomparison was performed to analyze the VIIRS radiometric performance. It was observed that some of the VIIRS bands such as M5 and M7 suggest bias on the order of 1.5% or more for most of the time period since early launch. VIIRS bias trends keep changing over time which can be mainly correlated to calibration updates and instrument anomalies. Results on VIIRS on-orbit calibration performance and its bias since early launch will be presented during meeting to help users better understand the data quality and its impacts on broader scientific research and applications.

  3. Thermal Return Reflection Method for Resolving Emissivity and Temperature in Radiometric Measurements

    SciTech Connect

    Woskov, Paul P.; Sundaram, S. K.

    2002-11-15

    A radiometric method for resolving the emissivity, e, and temperature, T, in thermal emission measurements is presented. Thermal radiation from a viewed source is split by a beamsplitter between a radiometer and a mirror aligned to return a part of the thermal radiation back to the source. The ratio of the thermal signal with and without a return reflection provides a measurement of the emissivity without need of any other probing sources. The analytical expressions that establish this relationship are derived taking into account waveguide/optic losses and sources between the radiometer and viewed sample. The method is then applied to thermal measurements of several refractory materials at temperatures up to 1150 ?C. A 137 GHz radiometer is used to measure the emissivity and temperature of an alumina brick, an Inconel 690 plate, and two grades of silicon carbide. Reasonable temperature agreement is achieved with an independent thermocouple measurement. However, when the emissivity approaches zero, as in the case of the Inconel plate, radiometric temperature determinations are inaccurate, though an emissivity near zero is correctly measured. This method is expected to be of considerable value to non-contact thermal analysis applications of materials.

  4. Radiometric Survey in Western Afghanistan: A Website for Distribution of Data

    USGS Publications Warehouse

    Sweeney, Ronald E.; Kucks, Robert P.; Hill, Patricia L.; Finn, Carol A.

    2007-01-01

    Radiometric (uranium content, thorium content, potassium content, and gamma-ray intensity) and related data were digitized from radiometric and survey route location maps of western Afghanistan published in 1976. The uranium content data were digitized along contour lines from 33 maps in a series entitled 'Map of Uranium (Radium) Contents of Afghanistan (Western Area),' compiled by V. N. Kirsanov and R. S. Dershimanov. The thorium content data were digitized along contour lines from 33 maps in a series entitled 'Map of Thorium Contents of Afghanistan (Western Area),' compiled by V. N. Kirsanov and R. S. Dershimanov. The potassium content data were digitized along contour lines from 33 maps in a series entitled 'Map of Potassium Contents of Afghanistan (Western Area),' compiled by V. N. Kirsanov and R. S. Dershimanov. The gamma-ray intensity data were digitized along contour lines from 33 maps in a series entitled 'Map of Gamma-Field of Afghanistan (Western Area),' compiled by V. N. Kirsanov and R. S. Dershimanov. The survey route location data were digitized along flight-lines located on 33 maps in a series entitled 'Survey Routes Location and Contours of Flight Equal Altitudes. Western Area of Afghanistan,' compiled by Z. A. Alpatova, V. G. Kurnosov, and F. A. Grebneva.

  5. Sensor Correction and Radiometric Calibration of a 6-BAND Multispectral Imaging Sensor for Uav Remote Sensing

    NASA Astrophysics Data System (ADS)

    Kelcey, J.; Lucieer, A.

    2012-07-01

    The increased availability of unmanned aerial vehicles (UAVs) has resulted in their frequent adoption for a growing range of remote sensing tasks which include precision agriculture, vegetation surveying and fine-scale topographic mapping. The development and utilisation of UAV platforms requires broad technical skills covering the three major facets of remote sensing: data acquisition, data post-processing, and image analysis. In this study, UAV image data acquired by a miniature 6-band multispectral imaging sensor was corrected and calibrated using practical image-based data post-processing techniques. Data correction techniques included dark offset subtraction to reduce sensor noise, flat-field derived per-pixel look-up-tables to correct vignetting, and implementation of the Brown- Conrady model to correct lens distortion. Radiometric calibration was conducted with an image-based empirical line model using pseudo-invariant features (PIFs). Sensor corrections and radiometric calibration improve the quality of the data, aiding quantitative analysis and generating consistency with other calibrated datasets.

  6. Radiometric calibration of ocean color satellite sensors using AERONET-OC data.

    PubMed

    Hlaing, Soe; Gilerson, Alexander; Foster, Robert; Wang, Menghua; Arnone, Robert; Ahmed, Sam

    2014-09-22

    Radiometric vicarious calibration of ocean color (OC) satellite sensors is carried out through the full sunlight path radiative transfer (RT) simulations of the coupled ocean-atmosphere system based on the aerosol and water-leaving radiance data from AERONET-OC sites for the visible and near-infrared (NIR) bands. Quantitative evaluation of the potential of such approach for achieving the radiometric accuracies of OC satellite sensors is made by means of direct comparisons between simulated and satellite measured top of atmosphere (TOA) radiances. Very high correlations (R ≥ 0.96 for all visible channels) are achieved for the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor when this approach is applied with the data from the LISCO and WaveCIS AERONET-OC sites. Vicarious calibration gain factors derived with this approach are highly consistent, with comparisons between the two sites exhibiting around 0.5% discrepancy in the blue and green parts of the spectrum, while their average temporal variability is also within 0.28% - 1.23% permitting the approach to be used, at this stage, for verification of sensor calibration performance. PMID:25321808

  7. An Empirical Approach to Ocean Color Data: Reducing Bias and the Need for Post-Launch Radiometric Re-Calibration

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.; Casey, Nancy W.; O'Reilly, John E.; Esaias, Wayne E.

    2009-01-01

    A new empirical approach is developed for ocean color remote sensing. Called the Empirical Satellite Radiance-In situ Data (ESRID) algorithm, the approach uses relationships between satellite water-leaving radiances and in situ data after full processing, i.e., at Level-3, to improve estimates of surface variables while relaxing requirements on post-launch radiometric re-calibration. The approach is evaluated using SeaWiFS chlorophyll, which is the longest time series of the most widely used ocean color geophysical product. The results suggest that ESRID 1) drastically reduces the bias of ocean chlorophyll, most impressively in coastal regions, 2) modestly improves the uncertainty, and 3) reduces the sensitivity of global annual median chlorophyll to changes in radiometric re-calibration. Simulated calibration errors of 1% or less produce small changes in global median chlorophyll (less than 2.7%). In contrast, the standard NASA algorithm set is highly sensitive to radiometric calibration: similar 1% calibration errors produce changes in global median chlorophyll up to nearly 25%. We show that 0.1% radiometric calibration error (about 1% in water-leaving radiance) is needed to prevent radiometric calibration errors from changing global annual median chlorophyll more than the maximum interannual variability observed in the SeaWiFS 9-year record (+/- 3%), using the standard method. This is much more stringent than the goal for SeaWiFS of 5% uncertainty for water leaving radiance. The results suggest ocean color programs might consider less emphasis of expensive efforts to improve post-launch radiometric re-calibration in favor of increased efforts to characterize in situ observations of ocean surface geophysical products. Although the results here are focused on chlorophyll, in principle the approach described by ESRID can be applied to any surface variable potentially observable by visible remote sensing.

  8. Structure of Serum Albumin

    NASA Technical Reports Server (NTRS)

    Carter, Daniel C.; Ho, Joseph X.

    1994-01-01

    Because of its availability, low cost, stability, and unusual ligand-binding properties, serum albumin has been one of the mst extensively studied and applied proteins in biochemistry. However, as a protein, albumin is far from typical, and the widespread interest in and application of albumin have not been balanced by an understanding of its molecular structure. Indeed, for more than 30 years structural information was surmised based solely on techniques such as hydrodynamics, low-angle X-ray scattering, and predictive methods.

  9. OCRA radiometric cloud fractions for GOME-2 on MetOp-A/B

    NASA Astrophysics Data System (ADS)

    Lutz, Ronny; Loyola, Diego; Gimeno García, Sebastián; Romahn, Fabian

    2016-05-01

    This paper describes an approach for cloud parameter retrieval (radiometric cloud-fraction estimation) using the polarization measurements of the Global Ozone Monitoring Experiment-2 (GOME-2) onboard the MetOp-A/B satellites. The core component of the Optical Cloud Recognition Algorithm (OCRA) is the calculation of monthly cloud-free reflectances for a global grid (resolution of 0.2° in longitude and 0.2° in latitude) to derive radiometric cloud fractions. These cloud fractions will serve as a priori information for the retrieval of cloud-top height (CTH), cloud-top pressure (CTP), cloud-top albedo (CTA) and cloud optical thickness (COT) with the Retrieval Of Cloud Information using Neural Networks (ROCINN) algorithm. This approach is already being implemented operationally for the GOME/ERS-2 and SCIAMACHY/ENVISAT sensors and here we present version 3.0 of the OCRA algorithm applied to the GOME-2 sensors. Based on more than five years of GOME-2A data (April 2008 to June 2013), reflectances are calculated for ≈ 35 000 orbits. For each measurement a degradation correction as well as a viewing-angle-dependent and latitude-dependent correction is applied. In addition, an empirical correction scheme is introduced in order to remove the effect of oceanic sun glint. A comparison of the GOME-2A/B OCRA cloud fractions with colocated AVHRR (Advanced Very High Resolution Radiometer) geometrical cloud fractions shows a general good agreement with a mean difference of -0.15 ± 0.20. From an operational point of view, an advantage of the OCRA algorithm is its very fast computational time and its straightforward transferability to similar sensors like OMI (Ozone Monitoring Instrument), TROPOMI (TROPOspheric Monitoring Instrument) on Sentinel 5 Precursor, as well as Sentinel 4 and Sentinel 5. In conclusion, it is shown that a robust, accurate and fast radiometric cloud-fraction estimation for GOME-2 can be achieved with OCRA using polarization measurement devices (PMDs).

  10. A Traceable Ground to On-Orbit Radiometric Calibration System for the Solar Reflective Wavelength Region

    NASA Technical Reports Server (NTRS)

    Heath, Donald F.; Georgiev, Georgi

    2012-01-01

    This paper describes the combination of a Mie scattering spectral BSDF and BTDF albedo standard whose calibration is traceable to the NIST SIRCUS Facility or the NIST STARR II Facility. The Space-based Calibration Transfer Spectroradiometer (SCATS) sensor uses a simple, invariant optical configuration and dedicated narrow band spectral channel modules to provide very accurate, polarization-insensitive, stable measurements of earth albedo and lunar disk albedo. Optical degradation effects on calibration stability are eliminated through use of a common optical system for observations of the Sun, Earth, and Moon. The measurements from space would be traceable to SI units through preflight calibrations of radiance and irradiance at NIST's SIRCUS facility and the invariant optical system used in the sensor. Simultaneous measurements are made in multiple spectral channels covering the solar reflective wavelength range of 300 nm to 2.4 microns. The large dynamic range of signals is handled by use of single-element, highly-linear detectors, stable discrete electronic components, and a non imaging optical configuration. Up to 19 spectral modules can be mounted on a single-axis drive to give direct pointing at the Earth and at least once per orbit view of the Sun and Moon. By observing the Sun on every orbit, the most stringent stability requirements of the system are limited to short time periods. The invariant optical system for both radiance and irradiance measurements also give excellent transfer to-orbit SI traceability. Emerging instrumental requirements for remotely sensing tropospheric trace species have led to a rethinking by some of the paradigm for Systeme International d'Unites (SI) traceability of the spectral irradiance and radiance radiometric calibrations to spectral albedo (sr(exp -1)) which is not a SI unit. In the solar reflective wavelength region the spectral albedo calibrations are tied often to either the spectral albedo of a solar diffuser or the Moon

  11. Local-scale flood mapping on vegetated floodplains from radiometrically calibrated airborne LiDAR data

    NASA Astrophysics Data System (ADS)

    Malinowski, Radosław; Höfle, Bernhard; Koenig, Kristina; Groom, Geoff; Schwanghart, Wolfgang; Heckrath, Goswin

    2016-09-01

    Knowledge about the magnitude of localised flooding of riverine areas is crucial for appropriate land management and administration at regional and local levels. However, detection and delineation of localised flooding with remote sensing techniques are often hampered on floodplains by the presence of herbaceous vegetation. To address this problem, this study presents the application of full-waveform airborne laser scanning (ALS) data for detection of floodwater extent. In general, water surfaces are characterised by low values of backscattered energy due to water absorption of the infrared laser shots, but the exact strength of the recorded laser pulse depends on the area covered by the targets located within a laser pulse footprint area. To account for this we analysed the physical quantity of radiometrically calibrated ALS data, the backscattering coefficient, in relation to water and vegetation coverage within a single laser footprint. The results showed that the backscatter was negatively correlated to water coverage, and that of the three distinguished classes of water coverage (low, medium, and high) only the class with the largest extent of water cover (>70%) had relatively distinct characteristics that can be used for classification of water surfaces. Following the laser footprint analysis, three classifiers, namely AdaBoost with Decision Tree, Naïve Bayes and Random Forest, were utilised to classify laser points into flooded and non-flooded classes and to derive the map of flooding extent. The performance of the classifiers is highly dependent on the set of laser points features used. Best performance was achieved by combining radiometric and geometric laser point features. The accuracy of flooding maps based solely on radiometric features resulted in overall accuracies of up to 70% and was limited due to the overlap of the backscattering coefficient values between water and other land cover classes. Our point-based classification methods assure a high

  12. Miniaturized aerosol, cloud and radiometric payloads for small unmanned aerial vehicles

    NASA Astrophysics Data System (ADS)

    Roberts, G.; Corrigan, C.; Ramana, M.; Ramanathan, V.

    2007-12-01

    Miniaturized aerosol, cloud and radiometric payloads were developed to advance atmospheric observations using small autonomous unmanned aerial vehicles (AUAVs). The observing system consisted of three vertically- stacked AUAVs to allow simultaneous sampling of the earth's atmosphere - offering new insights to radiation budgets and aerosol-cloud interactions. To accomplish this campaign, aerosol, cloud, radiometric instruments, and an integrated data acquisition system have been miniaturized with a total payload weight less than 4 kg and power less than 30 W. Due to size and weight limitations of the lightweight AUAV platform, the payloads are mission-specific and outfitted to perform a defined set of measurements depending on the scientific goals. These measurements include aerosol concentration, aerosol size distribution, aerosol absorption, cloud drop concentration and size distribution, solar radiation fluxes (visible and broadband), temperature, pressure, and relative humidity. The data integrity has been validated using standard calibration routines in conjunction with ground-based and laboratory instruments, as well as inter-aircraft comparisons. The instrument suite includes commercially-available instruments that have been repackaged or redesigned to minimize weight and volume and improve their performance. Several instruments have been completely redesigned including an aerosol inlet, absorption photometer based on an aethelometer and cloud condensation nucleus (CCN) counter. Re-engineering of the absorption photometer's optics and electronics improved its performance at three wavelengths. The CCN instrument has been reduced to less than 2kg (compared to 28 kg) without compromising performance utilizing theory and model simulations to optimize design and define operating limits. A shrouded aerosol inlet was specifically designed for the AUAVs to minimize sample biases in aerosol number and size distributions. The radiometric sensors perform well during

  13. Microwave and Millimeter-Wave Radiometric Studies of Temperature, Water Vapor and Clouds

    SciTech Connect

    Westwater, Edgeworth

    2011-05-06

    The importance of accurate measurements of column amounts of water vapor and cloud liquid has been well documented by scientists within the Atmospheric Radiation Measurement (ARM) Program. At the North Slope of Alaska (NSA), both microwave radiometers (MWR) and the MWRProfiler (MWRP), been used operationally by ARM for passive retrievals of the quantities: Precipitable Water Vapor (PWV) and Liquid Water Path (LWP). However, it has been convincingly shown that these instruments are inadequate to measure low amounts of PWV and LWP. In the case of water vapor, this is especially important during the Arctic winter, when PWV is frequently less than 2 mm. For low amounts of LWP (< 50 g/m{sup 2}), the MWR and MWRP retrievals have an accuracy that is also not acceptable. To address some of these needs, in March-April 2004, NOAA and ARM conducted the NSA Arctic Winter Radiometric Experiment - Water Vapor Intensive Operational Period at the ARM NSA/Adjacent Arctic Ocean (NSA/AAO) site. After this experiment, the radiometer group at NOAA moved to the Center for Environmental Technology (CET) of the Department of Electrical and Computer Engineering of the University of Colorado at Boulder. During this 2004 experiment, a total of 220 radiosondes were launched, and radiometric data from 22.235 to 380 GHz were obtained. Primary instruments included the ARM MWR and MWRP, a Global Positioning System (GPS), as well as the CET Ground-based Scanning Radiometer (GSR). We have analyzed data from these instruments to answer several questions of importance to ARM, including: (a) techniques for improved water vapor measurements; (b) improved calibration techniques during cloudy conditions; (c) the spectral response of radiometers to a variety of conditions: clear, liquid, ice, and mixed phase clouds; and (d) forward modeling of microwave and millimeter wave brightness temperatures from 22 to 380 GHz. Many of these results have been published in the open literature. During the third year of

  14. The Importance of Post-Launch, On-Orbit Absolute Radiometric Calibration for Remote Sensing Applications

    NASA Astrophysics Data System (ADS)

    Kuester, M. A.

    2015-12-01

    Remote sensing is a powerful tool for monitoring changes on the surface of the Earth at a local or global scale. The use of data sets from different sensors across many platforms, or even a single sensor over time, can bring a wealth of information when exploring anthropogenic changes to the environment. For example, variations in crop yield and health for a specific region can be detected by observing changes in the spectral signature of the particular species under study. However, changes in the atmosphere, sun illumination and viewing geometries during image capture can result in inconsistent image data, hindering automated information extraction. Additionally, an incorrect spectral radiometric calibration will lead to false or misleading results. It is therefore critical that the data being used are normalized and calibrated on a regular basis to ensure that physically derived variables are as close to truth as is possible. Although most earth observing sensors are well-calibrated in a laboratory prior to launch, a change in the radiometric response of the system is inevitable due to thermal, mechanical or electrical effects caused during the rigors of launch or by the space environment itself. Outgassing and exposure to ultra-violet radiation will also have an effect on the sensor's filter responses. Pre-launch lamps and other laboratory calibration systems can also fall short in representing the actual output of the Sun. A presentation of the differences in the results of some example cases (e.g. geology, agriculture) derived for science variables using pre- and post-launch calibration will be presented using DigitalGlobe's WorldView-3 super spectral sensor, with bands in the visible and near infrared, as well as in the shortwave infrared. Important defects caused by an incomplete (i.e. pre-launch only) calibration will be discussed using validation data where available. In addition, the benefits of using a well-validated surface reflectance product will be

  15. Mapping of local-scale flooding on vegetated floodplains from radiometrically calibrated airborne laser scanning data

    NASA Astrophysics Data System (ADS)

    Malinowski, Radosław; Höfle, Bernhard; König, Kristina; Groom, Geoffrey; Schwanghart, Wolfgang; Heckrath, Goswin

    2014-05-01

    The agricultural use of riverine lowlands is often dependent on complex hydrological regimes including localized flooding. Knowledge about spatio-temporal inundation patterns enables a better understanding of the state of agricultural areas in lowlands and provides valuable and objective information on land suitability for land use administration and environmental planning. Data from Airborne Laser Scanning (ALS), also referred to as LiDAR, have become one of the most important sources of elevation data during the last two decades. Recently, geometric and radiometric attributes of ALS have also been explored for analysing the extent of water surfaces. Thus, the main objective of this work is to develop a method for mapping the spatial extent of floodplain inundation by means of remote sensing data. Our study focusses on analysing floodwaters partly covered by some vegetation, which is a major challenge in flood mapping. We hypothesize that ALS data due to its high sampling density and high rate of canopy penetration can effectively be used for floodwater detection in such areas. This research utilizes full-waveform ALS data with an average point density of 20 points/m2 obtained for an area of ca. 8 km2 of the Nørreå River valley in Jutland, Denmark. The study area is characterised by the presence of improved or semi-improved grasslands (meadows and pasture), few arable fields, irregularly scattered group of trees and bushes, and an extensive ditch network. Our approach is based on an inspection of properties of single laser points with regard to water vs. vegetation coverage within the laser footprint, which is compared with very detailed field reference data. Exploratory analysis and classification of ALS data were preceded by radiometric calibration of point cloud data, utilizing in situ measurements of reference targets reflectance. The resulting calibration derivatives provide very stable estimates of surface characteristics and are used as the main input in

  16. Synergistic application of geometric and radiometric features of LiDAR data for urban land cover mapping.

    PubMed

    Qin, Yuchu; Li, Shihua; Vu, Tuong-Thuy; Niu, Zheng; Ban, Yifang

    2015-06-01

    Urban land cover map is essential for urban planning, environmental studies and management. This paper aims to demonstrate the potential of geometric and radiometric features derived from LiDAR waveform and point cloud data in urban land cover mapping with both parametric and non-parametric classification algorithms. Small footprint LiDAR waveform data acquired by RIEGL LMS-Q560 in Zhangye city, China is used in this study. A LiDAR processing chain is applied to perform waveform decomposition, range determination and radiometric characterization. With the synergic utilization of geometric and radiometric features derived from LiDAR data, urban land cover classification is then conducted using the Maximum Likelihood Classification (MLC), Support Vector Machines (SVM) and random forest algorithms. The results suggest that the random forest classifier achieved the most accurate result with overall classification accuracy of 91.82% and the kappa coefficient of 0.88. The overall accuracies of MLC and SVM are 84.02, and 88.48, respectively. The study suggest that the synergic utilization of geometric and radiometric features derived from LiDAR data can be efficiently used for urban land cover mapping, the non-parametric random forest classifier is a promising approach for the various features with different physical meanings. PMID:26072748

  17. The Relationship between Balancing Reactions and Reaction Lifetimes: A Consideration of the Potassium-Argon Radiometric Method for Dating Minerals

    ERIC Educational Resources Information Center

    Howard, William A.

    2005-01-01

    A detailed examination of a commonly accepted practice in geology offers an example of how to stimulate critical thinking, teaches students how to read reactions, and challenges students to formulate better experiments for determining mineral ages more accurately. A demonstration of a Potassium-Argon radiometric method for dating minerals is…

  18. Landsat: radiometric and topographic correction of satellite imagery (R package)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most Geographic Information System software includes routines for atmospheric and topograhic correction of satellite imagery such as that taken by Landsat. Radiometric correction is an active area of research, and new, improved methods are rarely if ever available for testing and application. The R...

  19. Geometric Calibration and Radiometric Correction of LiDAR Data and Their Impact on the Quality of Derived Products

    PubMed Central

    Habib, Ayman F.; Kersting, Ana P.; Shaker, Ahmed; Yan, Wai-Yeung

    2011-01-01

    LiDAR (Light Detection And Ranging) systems are capable of providing 3D positional and spectral information (in the utilized spectrum range) of the mapped surface. Due to systematic errors in the system parameters and measurements, LiDAR systems require geometric calibration and radiometric correction of the intensity data in order to maximize the benefit from the collected positional and spectral information. This paper presents a practical approach for the geometric calibration of LiDAR systems and radiometric correction of collected intensity data while investigating their impact on the quality of the derived products. The proposed approach includes the use of a quasi-rigorous geometric calibration and the radar equation for the radiometric correction of intensity data. The proposed quasi-rigorous calibration procedure requires time-tagged point cloud and trajectory position data, which are available to most of the data users. The paper presents a methodology for evaluating the impact of the geometric calibration on the relative and absolute accuracy of the LiDAR point cloud. Furthermore, the impact of the geometric calibration and radiometric correction on land cover classification accuracy is investigated. The feasibility of the proposed methods and their impact on the derived products are demonstrated through experimental results using real data. PMID:22164121

  20. Geometric calibration and radiometric correction of LiDAR data and their impact on the quality of derived products.

    PubMed

    Habib, Ayman F; Kersting, Ana P; Shaker, Ahmed; Yan, Wai-Yeung

    2011-01-01

    LiDAR (Light Detection And Ranging) systems are capable of providing 3D positional and spectral information (in the utilized spectrum range) of the mapped surface. Due to systematic errors in the system parameters and measurements, LiDAR systems require geometric calibration and radiometric correction of the intensity data in order to maximize the benefit from the collected positional and spectral information. This paper presents a practical approach for the geometric calibration of LiDAR systems and radiometric correction of collected intensity data while investigating their impact on the quality of the derived products. The proposed approach includes the use of a quasi-rigorous geometric calibration and the radar equation for the radiometric correction of intensity data. The proposed quasi-rigorous calibration procedure requires time-tagged point cloud and trajectory position data, which are available to most of the data users. The paper presents a methodology for evaluating the impact of the geometric calibration on the relative and absolute accuracy of the LiDAR point cloud. Furthermore, the impact of the geometric calibration and radiometric correction on land cover classification accuracy is investigated. The feasibility of the proposed methods and their impact on the derived products are demonstrated through experimental results using real data. PMID:22164121

  1. Modelling Surface Energy Fluxes over Maize using a Two-Source Patch Model and Radiometric Soil and Canopy Temperature Observations.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Models estimating surface energy fluxes over partial canopy cover with thermal remote sensing must account for significant differences between the radiometric temperatures and turbulent exchange rates associated with the soil and canopy components of the thermal pixel scene. Recent progress in separ...

  2. In-flight calibration of the spectral and radiometric characteristics of AVIRIS in 1991

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Conel, James E.; Bruegge, Carol J.; Margolis, Jack S.; Carrere, Veronique; Vane, Gregg; Hoover, Gordon

    1992-01-01

    On 7 Mar. 1991, an in-flight calibration experiment was held at the Ivanpah Playa in southeastern California for the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) imaging spectrometer. Five AVIRIS overflights were acquired of a calibration target designated on the Ivanpah Playa surface. At the time of the overflights, the reflectance of the calibration target was measured with a field spectrometer. In addition, the atmospheric optical depths and water vapor abundance were measured from a radiometer station adjacent to the calibration target. These in-situ measurements were used to constrain the MODTRAN radiative transfer code to model the upwelling spectral radiance incident to the sensor aperture during the overflights. Analyses of this modeled radiance in conjunction with the laboratory-calibrated radiance were used to determine the spectral and radiometric calibration of AVIRIS while in flight.

  3. Classification of passive microwave signatures of sea ice based on radiometric textures - preliminary results

    SciTech Connect

    Cooper, R.A.; Full, W.E.; Eppler, D.T.

    1996-11-01

    The purpose of this study is to classify sea ice quantitatively using passive microwave signatures. In order to define key characteristics of each of the major sea ice type or feature, it is necessary to capitalize on different radiometric signatures that each produces and assign numeric values to them. The relationship of adjacent pixels at nadir position were analyzed using co-occurrence matrices. Portions of this extremely large data set were submitted to multivariate algorithms, specifically to non-constant sum linear unmixing methods, which identified the key variables, number of ice-types and features, and distinct characteristics which defined them. For the section of the Greenland ice-pack investigated, four major ice-types/features were identified. These were related to age of ice and fracture history. The variables that carried the majority of the information were co-occurrence measures of energy, entropy, and maximum probability, and average pixel intensity. 32 refs., 2 figs.

  4. High-precision radiometric tracking for planetary approach and encounter in the inner solar system

    NASA Technical Reports Server (NTRS)

    Christensen, C. S.; Thurman, S. W.; Davidson, J. M.; Finger, M. H.; Folkner, W. M.

    1989-01-01

    The benefits of improved radiometric tracking data have been studied for planetary approach within the inner Solar System using the Mars Rover Sample Return trajectory as a model. It was found that the benefit of improved data to approach and encounter navigation was highly dependent on the a priori uncertainties assumed for several non-estimated parameters, including those for frame-tie, Earth orientation, troposphere delay, and station locations. With these errors at their current levels, navigational performance was found to be insensitive to enhancements in data accuracy. However, when expected improvements in these errors are modeled, performance with current-accuracy data significantly improves, with substantial further improvements possible with enhancements in data accuracy.

  5. [Radiometric assessment of wrist angle values, linear parameters of the forearm and wrist ratios].

    PubMed

    Baczkowski, Bogusław; Mechlińska-Baczkowska, Janina; Lorczyński, Adam

    2006-01-01

    With the device of our own invention suitable for static X-ray examination of the wrist 12 radiographic parameters were evaluated. 100 radiograms regarded normal were analyzed, obtained as a comparative in unilateral wrist trauma patients group. Age of the patients ranged from 18 to 60 years. No comparative studies in regard to sex were performed. Obtained data were statistically analyzed. Subsequent values of the radiometric parameters were obtained: scaphoid-lunate angle (SL) 48.61 degrees, radio-lunate angle (RL): -0.83 degrees, palmar inclination of the distal radius metaphysis (RI): 25.96. The most significant linear parameters measured: ulnar length 0.18 mm, ulnar transposition (UT): 0.339 mm. PMID:17131729

  6. Radiometric calibration of an airborne multispectral scanner. [of Thematic Mapper Simulator

    NASA Technical Reports Server (NTRS)

    Markham, Brian L.; Ahmad, Suraiya P.; Jackson, Ray D.; Moran, M. S.; Biggar, Stuart F.; Gellman, David I.; Slater, Philip N.

    1991-01-01

    The absolute radiometric calibration of the NS001 Thematic Mapper Simulator reflective channels was examined based on laboratory tests and in-flight comparisons to ground measurements. The NS001 data are calibrated in-flight by reference to the NS001 internal integrating sphere source. This source's power supply or monitoring circuitry exhibited greater instability in-flight during 1988-1989 than in the laboratory. Extrapolating laboratory behavior to in-flight data resulted in 7-20 percent radiance errors relative to ground measurements and atmospheric modeling. Assuming constancy in the source's output between laboraotry and in-flight resulted in generally smaller errors. Upgrades to the source's power supply and monitoring circuitry in 1990 improved its in-flight stability, though in-flight ground reflectance based calibration tests have not yet been performed.

  7. Pilot study of the application of Tellus airborne radiometric and soil geochemical data for radon mapping.

    PubMed

    Appleton, J D; Miles, J C H; Green, B M R; Larmour, R

    2008-10-01

    The scope for using Tellus Project airborne gamma-ray spectrometer and soil geochemical data to predict the probability of houses in Northern Ireland having high indoor radon concentrations is evaluated, in a pilot study in the southeast of the province, by comparing these data statistically with in-house radon measurements. There is generally good agreement between radon maps modelled from the airborne radiometric and soil geochemical data using multivariate linear regression analysis and conventional radon maps which depend solely on geological and indoor radon data. The radon maps based on the Tellus Project data identify some additional areas where the radon risk appears to be relatively high compared with the conventional radon maps. One of the ways of validating radon maps modelled on the Tellus Project data will be to carry out additional indoor measurements in these areas. PMID:18562054

  8. In-progress absolute radiometric inflight calibration of the LANDSAT-4 sensors

    NASA Technical Reports Server (NTRS)

    Castle, K.; Dinguirard, M.; Ezra, C. E.; Holm, R. G.; Jackson, R. J.; Kastner, C. J.; Palmer, J. M.; Savage, R.; Slater, P. N.

    1983-01-01

    An approach is described for providing periodic inflight absolute radiometric calibrations of the LANDSAT-4 sensors by reference to selected, instrumented ground areas. Results of some early ground measurements and computer simulations are presented. Selection of a suitable ground reference site, accurate measurement of the spectral reflectance of the selected area, determination of atmospheric characteristics during the morning of the sensor overpass, reduction of the measured data and their use in an appropriate atmospheric radiative transfer program, and comparison of the radiance level data with the digital counts of for the images of the selected areas are discussed. Preliminary measurements of gypsum are being made as an aid in defining the characteristics of field equipment to be constructed and calibrated for use over the White Sands Missile Range.

  9. Evaluating Radiometric Sensitivity of LandSat 8 Over Coastal-Inland Waters

    NASA Technical Reports Server (NTRS)

    Pahlevan, Nima; Wei, Jian-Wei; Shaaf, Crystal B.; Schott, John R.

    2014-01-01

    The operational Land Imager (OLI) aboard Landsat 8 was launched in February 2013 to continue the Landsat's mission of monitoring earth resources at relatively high spatial resolution. Compared to Landsat heritage sensors, OLI has an additional 443-nm band (termed coastal/aerosol (CA) band), which extends its potential for mapping/monitoring water quality in coastal/inland waters. In addition, OLI's pushbroom design allows for longer integration time and, as a result, higher signal-to-noise ratio (SNR). Using a series of radiative transfer simulations, we provide insights into the radiometric sensitivity of OLI when studying coastal/inland waters. This will address how the changes in water constituents manifest at top-of-atmosphere (TOA) and whether the changes are resolvable at TOA (focal plane) relative to OLI's overall noise.

  10. Novel Hyperspectral Sun Photometer for Satellite Remote Sensing Data Radiometric Calibration and Atmospheric Aerosol Studies

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary; Ryan, Robert E.; Holekamp, Kara; Harrington, Gary; Frisbie, Troy

    2006-01-01

    A simple and cost-effective, hyperspectral sun photometer for radiometric vicarious remote sensing system calibration, air quality monitoring, and potentially in-situ planetary climatological studies, was developed. The device was constructed solely from off the shelf components and was designed to be easily deployable for support of short-term verification and validation data collects. This sun photometer not only provides the same data products as existing multi-band sun photometers, this device requires a simpler setup, less data acquisition time and allows for a more direct calibration approach. Fielding this instrument has also enabled Stennis Space Center (SSC) Applied Sciences Directorate personnel to cross calibrate existing sun photometers. This innovative research will position SSC personnel to perform air quality assessments in support of the NASA Applied Sciences Program's National Applications program element as well as to develop techniques to evaluate aerosols in a Martian or other planetary atmosphere.

  11. Effective infrared absorption coefficient for photothermal radiometric measurements in biological tissues.

    PubMed

    Majaron, Boris; Milanic, Matija

    2008-01-01

    Although photothermal radiometric (PTR) measurements commonly employ broad-band signal acquisition to increase the signal-to-noise ratio, all reported studies apply a fixed infrared (IR) absorption coefficient to simplify the involved signal analysis. In samples with large spectral variation of micro(lambda) in mid-IR, which includes most biological tissues, the selection of the effective IR absorption coefficient value (micro(eff)) can strongly affect the accuracy of the result. We present a novel analytical approach for the determination of optimal micro(eff) from spectral properties of the sample and radiation detector. In extensive numerical simulations of pulsed PTR temperature profiling in human skin using three common IR radiation detectors and several acquisition spectral bands, we demonstrate that our approach produces viable values micro(eff). Two previously used analytical estimations perform much worse in the same comparison. PMID:18182701

  12. The effects of the Arctic haze as determined from airborne radiometric measurements during AGASP II

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.; Ackerman, Thomas P.; Gore, Warren J. Y.

    1989-01-01

    The effect of the Arctic-haze aerosol on the parameters of solar radiation was investigated using airborne radiometric measurements of radiation parameters during the second Arctic Gas and Aerosol Sampling Project. Simultaneously with absorption measurements, optical depths and total, direct, and scattered radiation fields were determined. The experimentally determined parameters were used to define an aerosol model, which was then used to calculate atmospheric heating rate profiles. It was found that, besides the increased absorption (30 to 40 percent) and scattering of radiation by the atmosphere, Arctic haze reduces the surface absorption of solar energy by 6 to 10 percent, and the effective planetary albedo over ice surfaces by 3 to 6 percent.

  13. Observations of the moon by the global ozone monitoring experiment: radiometric calibration and lunar albedo.

    PubMed

    Dobber, M R; Goede, A P; Burrows, J P

    1998-11-20

    The Global Ozone Monitoring Experiment (GOME) is a new instrument, which was launched aboard the second European Remoting Sensing satellite ESA-ERS2 in 1995. For its long-term radiometric and spectral calibration the GOME observes the sun and less frequently the moon on a regular basis. These measurements of the lunar radiance and solar irradiance have been used in a study to determine, for the first time to the authors' knowledge, the geometric lunar albedo from 240 to 800 nm at high spectral resolution from space. For a waning moon there is good agreement with ground-based measurements in the visible region and with recent space-based measurements in the ultraviolet region. In addition, the use of these measurements for the characterization of in-orbit degradation of instruments operating in this spectral region has been adequately demonstrated. PMID:18301626

  14. Characterization of a diffraction grating as a simulant of a selective frequency antenna for radiometric applications

    NASA Astrophysics Data System (ADS)

    Pizzillo, Thomas J.

    1994-01-01

    This report details the study of a blazed diffraction grating as a simulant of a selective frequency antenna for radiometric applications. Specifically, the ability to direct and sweep a beam of millimeter wave (MMW) energy is explored as a potential means of munitions guidance. A grating was designed and built to direct incident energy into the negative first-order peak of the associated diffraction spectrum. A change of 1 GHz in the incident energy frequency is shown to produce a beam displacement of 0.30, a polarization dependence is shown to exist for energy in orders other than zero, and a limited scaling of the optical theory of diffraction to MMW energies is demonstrated to be feasible.

  15. Statistical synthesis of radiometric imaging formation in scanning radiometers with signal weight processing by Kravchenko windows

    NASA Astrophysics Data System (ADS)

    Volosyuk, V. K.; Kravchenko, V. F.; Pavlikov, V. V.; Pustovoit, V. I.

    2014-05-01

    Statistical optimization of the radiometric images (RMIs) algorithms formation in scanning radiometers with weight correction of the antenna amplitude-phase distribution and synchronous sliding strobing of the received noise-like signal by a function describing the antenna pattern corrected by temporal Kravchenko windows is performed for the first time. The ambiguity function (AF) of the scanning radiometer, which determines the RMI quality, is found. It is established that the AF shape substantially depends on the amplitude field distribution (AFD) in the antenna. It is shown that the use of the AFD in the antenna in the form of weight functions (classic and Kravchenko) makes it possible to correct the AF shape and to increase the RMI quality. A simulation of the RMI formation algorithm is performed. It follows from the analysis of simulation data that the use of the weight Kravchenko functions provides higher accuracy of the RMI restoration compared with classic weight functions.

  16. Antiquity of man in America indicated by radiometric dates on the Yuha burial site

    USGS Publications Warehouse

    Bischoff, J.L.; Merriam, R.; Childers, W.M.; Protsch, R.

    1976-01-01

    MUCH evidence suggests that man was present in the Western Hemisphere before 12,000 yr ago, but the case has remained less than conclusive 1. In some situations, the geological age of the site is reasonably well established but the association or nature of the artefacts is questionable2,3. In other cases, museum specimens of human bones dated by radiocarbon analysis of collagen lack desirable information concerning site location, geology, and stratigraphy even though the accuracy of their absolute ages seems valid4-6. We report here the results of radiometric dates of the Yuha burial site from Imperial County, California, for which the geology and stratigraphy have been documented and reported in detail7. ?? 1976 Nature Publishing Group.

  17. A Radiometric All-Sky Infrared Camera (RASICAM) for DES/CTIO

    SciTech Connect

    Lewis, Peter M.; Rogers, Howard; Schindler, Rafe H.; /SLAC

    2010-08-25

    A novel radiometric all-sky infrared camera [RASICAM] has been constructed to allow automated real-time quantitative assessment of night sky conditions for the Dark Energy Camera [DECam] located on the Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile. The camera is optimized to detect the position, motion and optical depth of thin, high (8-10km) cirrus clouds and contrails by measuring their apparent temperature above the night sky background. The camera system utilizes a novel wide-field equiresolution catadioptic mirror system that provides sky coverage of 2{pi} azimuth and 14-90{sup o} from zenith. Several new technological and design innovations allow the RASICAM system to provide unprecedented cloud detection and IR-based photometricity quantification. The design of the RASICAM system is presented.

  18. Electronic transport characterization of silicon wafers by spatially resolved steady-state photocarrier radiometric imaging

    SciTech Connect

    Wang, Qian; Li, Bincheng

    2015-09-28

    Spatially resolved steady-state photocarrier radiometric (PCR) imaging technique is developed to characterize the electronic transport properties of silicon wafers. Based on a nonlinear PCR theory, simulations are performed to investigate the effects of electronic transport parameters (the carrier lifetime, the carrier diffusion coefficient, and the front surface recombination velocity) on the steady-state PCR intensity profiles. The electronic transport parameters of an n-type silicon wafer are simultaneously determined by fitting the measured steady-state PCR intensity profiles to the three-dimensional nonlinear PCR model. The determined transport parameters are in good agreement with the results obtained by the conventional modulated PCR technique with multiple pump beam radii.

  19. Optimization of the design parameters for a wide-band radiometric system

    NASA Technical Reports Server (NTRS)

    Agrawal, P. K.

    1978-01-01

    The optimun design parameters for a swept frequency wide-band radiometric antenna system for spacecraft applications are studied. Wide band antenna systems are needed to observe layered surfaces which are frequency sensitive and require multiple measurements for interpretation. The lowest frequency band of interest is between 1.4 to 2.8 Ghz. Starting with a given size reflector fed in the offset mode by a corrugated horn located at the focus of the parabola, the primary performance indexes; e.g., half power beamwidth, cross polarization level, and overall beam efficiency were calculated over a wide frequency range (two to one) for different physical horn dimensions and for different values of f/D ratio. These data are used to find the best design under given restriction of reflector size and blockage.

  20. Prediction of radio frequency power generation of Neptune's magnetosphere from generalized radiometric Bode's law

    NASA Technical Reports Server (NTRS)

    Million, M. A.; Goertz, C. K.

    1988-01-01

    Magnetospheric radio frequency emission power has been shown to vary as a function of both solar wind and planetary values such as magnetic field by Kaiser and Desch (1984). Planetary magnetic fields have been shown to scale with planetary variables such as density and angular momentum by numerous researchers. This paper combines two magnetic scaling laws with the radiometric law to yield 'Bode's'-type laws governing planetary radio emissions. Further analysis allows the reduction of variables to planetary mass and orbital distance. These generalized laws are then used to predict the power otuput of Neptune to be about 1.6 x 10 to the 7th W; with the intensity peaking at about 3 MHz.

  1. A Liquid-Helium-Cooled Absolute Reference Cold Load forLong-Wavelength Radiometric Calibration

    SciTech Connect

    Bensadoun, M.; Witebsky, C.; Smoot, George F.; De Amici,Giovanni; Kogut, A.; Levin, S.

    1990-05-01

    We describe a large (78-cm) diameter liquid-helium-cooled black-body absolute reference cold load for the calibration of microwave radiometers. The load provides an absolute calibration near the liquid helium (LHe) boiling point, accurate to better than 30 mK for wavelengths from 2.5 to 25 cm (12-1.2 GHz). The emission (from non-LHe temperature parts of the cold load) and reflection are small and well determined. Total corrections to the LHe boiling point temperature are {le} 50 mK over the operating range. This cold load has been used at several wavelengths at the South Pole and at the White Mountain Research Station. In operation, the average LHe loss rate was {le} 4.4 l/hr. Design considerations, radiometric and thermal performance and operational aspects are discussed. A comparison with other LHe-cooled reference loads including the predecessor of this cold load is given.

  2. Application and sensitivity investigation of Fourier transforms for microwave radiometric inversions

    NASA Technical Reports Server (NTRS)

    Holmes, J. J.; Balanis, C. A.

    1974-01-01

    Existing microwave radiometer technology now provides a suitable method for remote determination of the ocean surface's absolute brightness temperature. To extract the brightness temperature of the water from the antenna temperature equation, an unstable Fredholm integral equation of the first kind was solved. Fast Fourier Transform techniques were used to invert the integral after it is placed into a cross-correlation form. Application and verification of the methods to a two-dimensional modeling of a laboratory wave tank system were included. The instability of the Fredholm equation was then demonstrated and a restoration procedure was included which smooths the resulting oscillations. With the recent availability and advances of Fast Fourier Transform techniques, the method presented becomes very attractive in the evaluation of large quantities of data. Actual radiometric measurements of sea water are inverted using the restoration method, incorporating the advantages of the Fast Fourier Transform algorithm for computations.

  3. Radiometric and geometric analysis of hyperspectral imagery acquired from an unmanned aerial vehicle

    SciTech Connect

    Hruska, Ryan; Mitchell, Jessica; Anderson, Matthew; Glenn, Nancy F.

    2012-09-17

    During the summer of 2010, an Unmanned Aerial Vehicle (UAV) hyperspectral in-flight calibration and characterization experiment of the Resonon PIKA II imaging spectrometer was conducted at the U.S. Department of Energy’s Idaho National Laboratory (INL) UAV Research Park. The purpose of the experiment was to validate the radiometric calibration of the spectrometer and determine the georegistration accuracy achievable from the on-board global positioning system (GPS) and inertial navigation sensors (INS) under operational conditions. In order for low-cost hyperspectral systems to compete with larger systems flown on manned aircraft, they must be able to collect data suitable for quantitative scientific analysis. The results of the in-flight calibration experiment indicate an absolute average agreement of 96.3%, 93.7% and 85.7% for calibration tarps of 56%, 24%, and 2.5% reflectivity, respectively. The achieved planimetric accuracy was 4.6 meters (based on RMSE).

  4. Retrievals of Column Water Vapor Using Millimeter-Wave Radiometric Measurements

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Racette, P.; Triesky, M. E.; Manning, W.; Hildebrand, Peter H. (Technical Monitor)

    2001-01-01

    Water vapor is one of the most important atmospheric constituents that has a critical impact on cloud formation (ice or liquid). It is also a source that needs to be accounted for in remote measurements of surface parameters. In the high-latitude regions, e.g., Antarctica, monitoring of the state of water vapor and its transport into and out of these regions is important towards our understanding the state of balance of ice sheets and its effect on the global sea level. The technique of retrieving low amount of column water vapor using the millimeter-wave radiometric measurements, as presented in this paper, will be very useful for these regions, especially during winter times when the atmosphere is relatively dry.

  5. Motion of an array of plates in a rarefied gas caused by radiometric force.

    PubMed

    Taguchi, Satoshi; Aoki, Kazuo

    2015-06-01

    In a rarefied gas in an infinitely long channel between two parallel plates, an array of infinitely many plates, arranged longitudinally with uniform interval, is placed along the channel. The array is assumed to be freely movable along the channel. If one side of each plate is heated, the radiometric force acts on it, and the array starts moving toward the cold sides of the plates. The final steady motion of the array, as well as the corresponding behavior of the gas, is investigated numerically on the basis of kinetic theory using the ellipsoidal statistical model of the Boltzmann equation. As the solution method, a finite-difference method, with a method of characteristics incorporated, that is able to capture the discontinuity in the velocity distribution function is employed. As the result, the local flow field near the edges of the plates and the terminal velocity of the array are obtained accurately for relatively small Knudsen numbers. PMID:26172792

  6. Landsat radiometric cross-calibration: extended analysis of tandem image data sets

    NASA Astrophysics Data System (ADS)

    Teillet, P. M.; Markham, Brian L.; Irish, Richard R.

    2005-10-01

    The paper presents the results of an extended analysis of image data sets acquired during the tandem-orbit configuration in 1999 for the purposes of radiometric cross-calibration of the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) and Landsat-5 Thematic Mapper (TM) sensors. Earlier work focused on the tandem pair for the Railroad Valley Playa, Nevada (RVPN) site to tie down the Landsat-5 TM calibration based on the more accurate Landsat-7 ETM+ calibration. This paper describes new results based on as many as eight tandem image pairs. The additional tandem images are of vegetated areas for which little or no ground reference data were available. Increasing the number of tandem pairs yielded results for the Landsat 5 TM gain coefficients within approximately +/- 1 % of the RVPN-based results in spectral bands 1, 2, 3 and 7, and within -2 % and -4 % of the RVPN-based results for spectral bands 4 and 5, respectively.

  7. Automated network at Railroad Valley, Nevada, for providing radiometric calibrations of OCO2

    NASA Astrophysics Data System (ADS)

    Bruegge, C. J.

    2011-12-01

    Traditional vicarious calibration experiments are used to provide radiometric calibrations for visible/ near-infrared sensors. Here a field team makes measurements of surface reflectance and atmospheric parameters co-incident with the flyby of an on-orbit sensor. These experiments are labor-intensive, and are often delayed waiting for clear-sky conditions. In June 2011 an automated test site was established at Railroad Valley, Nevada. Surface and atmospheric data from the test site are now downloaded automatically, and allow on-going calibrations for all overpass opportunities. This poster will describe the facility, and discuss early results in comparing top-of-atmosphere radiances to AVIRIS, MODIS, and GOSAT sensors.

  8. Radiometric Quality of the MODIS Bands at 667 and 678nm

    NASA Technical Reports Server (NTRS)

    Meister, Gerhard; Franz, Bryan A.

    2010-01-01

    The MODIS instruments on Terra and Aqua were designed to allow the measurement of chlorophyll fluorescence effects over ocean. The retrieval algorithm is based on the difference between the water-leaving radiances at 667nm and 678nm. The water-leaving radiances at these wavelengths are usually very low relative to the top- of-atmosphere radiances. The high radiometric accuracy needed to retrieve the small fluorescence signal lead to a dual gain design for the 667 and 678nm bands. This paper discusses the benefits obtained from this design choice and provides justification for the use of only one set of gains for global processing of ocean color products. Noise characteristics of the two bands and their related products are compared to other products of bands from 412nm to 2130nm. The impact of polarization on the two bands is discussed. In addition, the impact of stray light on the two bands is compared to other MODIS bands.

  9. Radiometric Quality of the MODIS Bands at 667 and 678nm

    NASA Technical Reports Server (NTRS)

    Meister, Gerhard; Franz, Bryan A.

    2011-01-01

    The MODIS instruments on Terra and Aqua were designed to allow the measurement of chlorophyll fluorescence effects over ocean. The retrieval algorithm is based on the difference between the water-leaving radiances at 667nm and 678nm. The water-leaving radiances at these wavelengths are usually very low relative to the top-of-atmosphere radiances. The high radiometric accuracy needed to retrieve the small fluorescence signal lead to a dual gain design for the 667 and 678nm bands. This paper discusses the benefits obtained from this design choice and provides justification for the use of only one set of gains for global processing of ocean color products. Noise characteristics of the two bands and their related products are compared to other products of bands from 412nm to 2130nm. The impact of polarization on the two bands is discussed. In addition, the impact of stray light on the two bands is compared to other MODIS bands.

  10. Investigation of LANDSAT follow-on thematic mapper spatial, radiometric and spectral resolution

    NASA Technical Reports Server (NTRS)

    Nalepka, R. F. (Principal Investigator); Morgenstern, J. P.; Kent, E. R.; Erickson, J. D.

    1976-01-01

    The author has identified the following significant results. Fine resolution M7 multispectral scanner data collected during the Corn Blight Watch Experiment in 1971 served as the basis for this study. Different locations and times of year were studied. Definite improvement using 30-40 meter spatial resolution over present LANDSAT 1 resolution and over 50-60 meter resolution was observed, using crop area mensuration as the measure. Simulation studies carried out to extrapolate the empirical results to a range of field size distributions confirmed this effect, showing the improvement to be most pronounced for field sizes of 1-4 hectares. Radiometric sensitivity study showed significant degradation of crop classification accuracy immediately upon relaxation from the nominally specified values of 0.5% noise equivalent reflectance. This was especially the case for data which were spectrally similar such as that collected early in the growing season and also when attempting to accomplish crop stress detection.

  11. Prediction of radio frequency power generation of Neptune's magnetosphere from generalized radiometric Bode's law

    NASA Astrophysics Data System (ADS)

    Millon, M. A.; Goertz, C. K.

    1988-01-01

    Magnetospheric radio frequency emission power has been shown to vary as a function of both solar wind and planetary values such as magnetic field by Kaiser and Desch. Planetary magnetic fields have been shown to scale with planetary variables such as density and angular momentum by numerous researchers. This paper combines two magnetic scaling laws (Busse's and Curtis Ness') with the radiometric law to yield "Bode's"-type laws governing planetary radio emission. Further analysis allows the reduction of variables to planetary mass and orbital distance. These generalized laws are then used to predict the power output of Neptune to be about 1.6×107W; with the intensity peaking at about 3 MHz.

  12. Infrared radiometric measurements of lunar disk temperatures during lunar eclipse on 15th June 2011

    NASA Astrophysics Data System (ADS)

    Maghrabi, A. H.

    2016-09-01

    Radiometric measurements of the total lunar eclipse on 15th June 2011 were carried out at the KACST observatory (lat. 21.25 N; long. 49.30 E), Jeddah, Saudi Arabia, using a locally designed, constructed and calibrated infrared detector. The basic detector is a Heimann TPS 534 thermopile with a 3° field of view and operating at wavelengths between 8 μm and 14 μm. The total phase of this eclipse lasted about 100 min, making it one of the darkest eclipses this century. The lunar temperature curve of this eclipse was obtained and showed comparable behavior with previously established infrared observations. We found that the lunar surface temperature decreased by about 147 K and 220 K during the partial and total eclipse phases, respectively, in comparison with the lunar temperature before the eclipse.

  13. Radiometric, geometric, and image quality assessment of ALOS AVNIR-2 and PRISM sensors

    USGS Publications Warehouse

    Saunier, S.; Goryl, P.; Chander, G.; Santer, R.; Bouvet, M.; Collet, B.; Mambimba, A.; Kocaman, Aksakal S.

    2010-01-01

    The Advanced Land Observing Satellite (ALOS) was launched on January 24, 2006, by a Japan Aerospace Exploration Agency (JAXA) H-IIA launcher. It carries three remote-sensing sensors: 1) the Advanced Visible and Near-Infrared Radiometer type 2 (AVNIR-2); 2) the Panchromatic Remote-Sensing Instrument for Stereo Mapping (PRISM); and 3) the Phased-Array type L-band Synthetic Aperture Radar (PALSAR). Within the framework of ALOS Data European Node, as part of the European Space Agency (ESA), the European Space Research Institute worked alongside JAXA to provide contributions to the ALOS commissioning phase plan. This paper summarizes the strategy that was adopted by ESA to define and implement a data verification plan for missions operated by external agencies; these missions are classified by the ESA as third-party missions. The ESA was supported in the design and execution of this plan by GAEL Consultant. The verification of ALOS optical data from PRISM and AVNIR-2 sensors was initiated 4 months after satellite launch, and a team of principal investigators assembled to provide technical expertise. This paper includes a description of the verification plan and summarizes the methodologies that were used for radiometric, geometric, and image quality assessment. The successful completion of the commissioning phase has led to the sensors being declared fit for operations. The consolidated measurements indicate that the radiometric calibration of the AVNIR-2 sensor is stable and agrees with the Landsat-7 Enhanced Thematic Mapper Plus and the Envisat MEdium-Resolution Imaging Spectrometer calibration. The geometrical accuracy of PRISM and AVNIR-2 products improved significantly and remains under control. The PRISM modulation transfer function is monitored for improved characterization. ?? 2006 IEEE.

  14. PLEIADES-HR 1A&1B image quality commissioning: innovative radiometric calibration methods and results

    NASA Astrophysics Data System (ADS)

    Martin, Vincent; Blanchet, Gwendoline; Kubik, Philippe; Lacherade, Sophie; Latry, Christophe; Lebegue, Laurent; Lenoir, Florie; Porez-Nadal, Florence

    2013-09-01

    PLEIADES is an earth observing system conducted by the French National Space Agency, CNES. It consists of two satellites launched on December 2011 (PHR-1A) and December 2012 (PHR-1B), both designed to provide optical pushbroom imagery on five spectral bands to civilian and defense users, with ground sample distance up to 70 cm. During inflight image quality commissioning, radiometric activities included inter-detector normalization coefficients computation, refocusing operations, MTF assessment and estimation of signal to noise ratios. This paper presents inflight results for both satellites. It focuses on several innovative methods that were implemented, taking advantage of the satellite platform great agility. These methods are based on processing images obtained through dedicated exotic guidance. In particular, slow-motion steering enables an efficient estimation of the instrumental noise model, since during acquisition each detector has been viewing a stable ground target along different time samples. Conversely, rotated retina guidance is used to guarantee that all different elementary detectors have successively viewed the same set of landscape samples during acquisition. Non-uniformity of detector sensitivities can then be characterized, and on-board coefficients used prior to compression can be calibrated in order to prevent vertical striping effects on operational images. Defocus control and Point Spread Function estimation can be easily obtained through processing acquisitions of stars associated to various spectral characteristics, for different adjustments of the refocusing system. All these methods allow an accurate estimation of radiometric performance on the whole range of specified spectral radiances, while drastically reducing the number of required acquisitions on natural targets.

  15. The Rosetta UV imaging spectrometer ALICE: First light optical and radiometric performance results

    NASA Astrophysics Data System (ADS)

    Slater, D. C.; Stern, S. A.; A'Hearn, M. F.; Bertaux, J. L.; Feldman, P. D.; Festou, M. C.

    2000-10-01

    We describe the design, scientific objectives, and "first-light" radiometric testing results of the Rosetta/ALICE instrument. ALICE is a lightweight (2.7 kg), low-power (4 W), and low-cost imaging spectrometer optimized for cometary ultraviolet spectroscopy. ALICE, which is funded by NASA (with hardware contributions from CNES, France), will fly on the ESA Rosetta Orbiter to characterize the cometary nucleus, coma, and nucleus/coma coupling of the target comet 46P/Wirtanen. It will obtain spatially-resolved, far-UV spectra of Wirtanen's nucleus and coma in the 700-2050 Å passband with a spectral resolution of 5-10 Å for extended sources that fill the entrance slit's field- of-view. ALICE is also the UV spectrometer model for the PERSI remote sensing suite proposed for the Pluto Kuiper Express (PKE) mission. ALICE uses modern technology to achieve its low mass and low power design specifications. It employs an off-axis telescope feeding a 0.15-m normal incidence Rowland circle spectrograph with a concave (toroidal) holographic reflection grating. The imaging microchannel plate (MCP) detector utilizes dual solar-blind opaque photocathodes of KBr and CsI deposited on a cylindrically-curved (7.5-cm radius) MCP Z-stack, and a matching 2-D cylindrically-curved double delay-line readout array with a 1024 x 32 pixel array format. This array format provides a point source response that is twice that originally proposed (Δ λ 3 Å). Three data taking modes are possible: (i) histogram image mode for 2-D images, (ii) pixel list mode with periodic time hacks for temporal studies, and (iii) count rate mode for broadband photometric studies. Optical and radiometric sensitivity performance results based on subsystem tests of the flight optics, detector, and preliminary integrated system level tests of the integrated ALICE flight model are presented and discussed.

  16. Monensin causes dose dependent inhibition of Mycobacterium avium subspecies paratuberculosis in radiometric culture

    PubMed Central

    Greenstein, Robert J; Su, Liya; Whitlock, Robert H; Brown, Sheldon T

    2009-01-01

    Background Mycobacterium avium subspecies paratuberculosis (MAP) causes a chronic wasting diarrheal disease in ruminants called Johne's disease, that is evocative of human inflammatory bowel disease (IBD). Agents used to treat IBD, called "anti-inflammatories", immuno-modulators" and "immuno-suppressants" inhibit MAP growth in culture. We concluded that, unknowingly, the medical profession has been treating MAP since sulfasalazine's introduction in 1942. Monensin, called a "Growth Enhancer" in cattle, ameliorates Johne's disease without a documented mechanism of action. We hypothesized that Monensin would inhibit MAP in culture. Methods Using the radiometric 14CO2 Bactec® system, that expresses mycobacterial growth in arbitrary growth index (GI) units, we studied the effect of Monensin on the growth kinetic of MAP isolated from humans with IBD ("Dominic", "Ben" & UCF-4) and cattle with Johne's disease (303 & ATCC 19698.) Results are expressed as percent inhibition of cumulative GI (%–ΔcGI). Results The positive control Clofazimine inhibits every strain tested. The negative controls Cycloheximide & Phthalimide, have no inhibition on any MAP strain. Monensin has dose dependent inhibition on every MAP strain tested. The most susceptible human isolate was UCF-4 (73% – ΔcGI at 1 μg/ml) and bovine isolate was 303 (73% – ΔcGI at 4 μg/ml.) Monensin additionally inhibits M. avium ATCC 25291 (87% – ΔcGI at 64 μg/ml) & BCG (92% – ΔcGI at 16 μg/ml). Discussion We show that in radiometric culture the "Growth Enhancer" Monensin causes dose dependent inhibition of mycobacteria including MAP. We posit that the "Growth Enhancer" effect of Monensin may, at least in part, be due to inhibition of MAP in clinical or sub-clinical Johne's disease. PMID:19338684

  17. Radiometric Cross-calibration of FORMOSAT-2 RSI with Landsat-8 OLI Image

    NASA Astrophysics Data System (ADS)

    Liao, Tun-Yu; Lin, Tang-Huang; Lin, Meng-Yue; Liu, Gin-Rong; Liu, Chian-Yi; Hsu, Kuo-Hsien; Chen, Nai-Yu; Wu, An-Ming

    2015-04-01

    FORMOSAT-2 satellite (FS-2) was launched in May, 2004. It is the first Earth observation satellite operated by the National Space Organization (NSPO) of Taiwan. The main payload housed in FS-2 is Remote Sensing Instrument (RSI) with high spatial resolution. Landsat-8 (L-8) is an American Earth observing satellite launched in February 2013 quite recently. The main sensor on L-8 is Operational Land Imager (OLI). For any optical sensors, ensuring the accurate radiance observing is the most important issue for the applications to the scientific researches and environmental monitoring. Since RSI is operated more than 10 years, the optical characters may be altered. Therefore, the goal in this research project is to examine radiometric coefficients of FS-2 RSI sensor by means of in-flight cross-calibration using L-8 OLI image as a reference. For FS-2 RSI sensor, OLI is not only a new and well calibrated sensor but also use the similar spectral bands and bandwidth which can provide a credible data for calibrating RSI. The desert areas are selected for the cross-calibration in this study, including Sahara desert in Africa and Sonoran desert in America. Those sites are usually used in other papers as a satellite sensor calibration site. The radiative transfer code, Second Simulation of a Satellite Signal in the Solar Spectrum (6S) is employed to drive land surface reflectance and the radiance RSI observed on the top of atmosphere. Eventually, the physical gains of RSI can be figured based on the relationship between observed radiance and the digital number. The results indicate that the changes of physical gains from the counter parts of pre-flight can reach in 10% in most spectral bands of RSI. Keywords: FORMOSAT-2 RSI, Landsat-8 OLI, In-flight radiometric calibration, Cross-calibration, Physical gain

  18. Orbit determination of the Lunar Reconnaissance Orbiter using laser ranging and radiometric tracking data

    NASA Astrophysics Data System (ADS)

    Löcher, Anno; Kusche, Jürgen

    2014-05-01

    The Lunar Reconnaissance Orbiter (LRO) launched in 2009 by the National Aeronautics and Space Administration (NASA) still orbits the Moon in a polar orbit at an altitude of 50 kilometers and below. Its main objective is the detailed exploration of the Moon's surface by means of the Lunar Orbiter Laser Altimeter (LOLA) and three high resolution cameras bundled in the Lunar Reconnaissance Orbiter Camera (LROC) unit. Referring these observations to a Moon-fixed reference frame requires the computation of highly accurate and consistent orbits. For this task only Earth-based observations are available, primarily radiometric tracking data from stations in the United States, Australia and Europe. In addition, LRO is prepared for one-way laser measurements from specially adapted sites. Currently, 10 laser stations participate more or less regularly in this experiment. For operational reasons, the official LRO orbits from NASA only include radiometric data so far. In this presentation, we investigate the benefit of the laser ranging data by feeding both types of observations in an integrated orbit determination process. All computations are performed by an in-house software development based on a dynamical approach improving orbit and force parameters in an iterative way. Special attention is paid to the determination of bias parameters, in particular of timing biases between radio and laser stations and the drift and aging of the LRO spacecraft clock. The solutions from the combined data set will be compared to radio- and laser-only orbits as well as to the NASA orbits. Further results will show how recent gravity field models from the GRAIL mission can improve the accuracy of the LRO orbits.

  19. Assessment of GOCI radiometric products using MERIS, MODIS and field measurements

    NASA Astrophysics Data System (ADS)

    Lamquin, Nicolas; Mazeran, Constant; Doxaran, David; Ryu, Joo-Hyung; Park, Young-Je

    2012-09-01

    The first Geostationary Ocean Color Imager (GOCI) launched by South Korea in June 2010 constitutes a major breakthrough in marine optics remote-sensing for its capabilities to observe the diurnal cycles of the ocean. The light signal recorded at eight wavelengths by the sensor allows, after correction for Solar illumination and atmospheric effects, the retrieval of coloured biogeochemical products such as the chlorophyll, suspended sediment and coloured dissolved organic matter concentrations every hour between 9:00 am and 4:00 pm local time around the Korean peninsula. However operational exploitation of the mission needs beforehand a sound validation of first the radiometric calibration, i.e. inspection of the top-of-atmosphere reflectance, and second atmospheric corrections for retrieval of the water-leaving reflectance at sea surface. This study constitutes a contribution to the quality assessment of the GOCI radiometric products generated by the Korea Ocean Satellite Center (KOSC) through comparison with concurrent data from the MODerate-resolution Imaging Spectroradiometer (MODIS, NASA) and MEdium Resolution Imaging Spectrometer (MERIS, ESA) sensors as well as in situ measurements. These comparisons are made with spatially and temporally collocated data. We focus on Rayleigh-corrected reflectance ( ρ RC ) and normalized remote-sensing marine reflectance (nRrs). Although GOCI compares reasonably well with MERIS and MODIS, what demonstrates the success of Ocean Colour in geostationary orbit, we show that the current GOCI atmospheric correction systematically masks out data over very turbid waters and needs further examination and correction for future release of the GOCI products.

  20. Field Measurement of Sand Dune Bidirectional Reflectance Characteristics for Absolute Radiometric Calibration of Optical Remote Sensing Data.

    NASA Astrophysics Data System (ADS)

    Coburn, C. A.; Logie, G.; Beaver, J.; Helder, D.

    2015-12-01

    The use of Pseudo Invariant Calibration Sites (PICS) for establishing the radiometric trending of optical remote sensing systems has a long history of successful implementation. Past studies have shown that the PICS method is useful for evaluating the trend of sensors over time or cross-calibration of sensors but was not considered until recently for deriving absolute calibration. Current interest in using this approach to establish absolute radiometric calibration stems from recent research that indicates that with empirically derived models of the surface properties and careful atmospheric characterisation Top of Atmosphere (TOA) reflectance values can be predicted and used for absolute sensor radiometric calibration. Critical to the continued development of this approach is the accurate characterization of the Bidirectional Reflectance Distribution Function (BRDF) of PICS sites. This paper presents the field data collected by a high-performance portable goniometer system in order to develop a BRDF model for the Algodones Dunes in California. These BRDF data are part of a larger study that is seeking to evaluate and quantify all aspects of this dune system (from regional effects to the micro scale optical properties of the sand) in order to provide an absolute radiometric calibration PICS. This paper presents the results of a dense temporal measurement sequence (several measurements per hour with high angular resolution), to yield detailed information on the nature of the surface reflectance properties. The BRDF data were collected covering typical view geometry of space borne sensors and will be used to close the loop on the calibration to create an absolute calibration target for optical satellite absolute radiometric calibration.

  1. Radiometric Measurement Comparisons Using Transfer Radiometers in Support of the Calibration of NASA's Earth Observing System (EOS) Sensors

    NASA Technical Reports Server (NTRS)

    Butler, James J.; Johnson, B. Carol; Brown, Steven W.; Yoon, Howard W.; Barnes, Robert A.; Markham, Brian L.; Biggar, Stuart F.; Zalewski, Edward F.; Spyak, Paul R.; Cooper, John W.; Sakuma, Fumihiro

    1999-01-01

    EOS satellite instruments operating in the visible through the shortwave infrared wavelength regions (from 0.4 micrometers to 2.5 micrometers) are calibrated prior to flight for radiance response using integrating spheres at a number of instrument builder facilities. The traceability of the radiance produced by these spheres with respect to international standards is the responsibility of the instrument builder, and different calibration techniques are employed by those builders. The National Aeronautics and Space Administration's (NASA's) Earth Observing System (EOS) Project Science Office, realizing the importance of preflight calibration and cross-calibration, has sponsored a number of radiometric measurement comparisons, the main purpose of which is to validate the radiometric scale assigned to the integrating spheres by the instrument builders. This paper describes the radiometric measurement comparisons, the use of stable transfer radiometers to perform the measurements, and the measurement approaches and protocols used to validate integrating sphere radiances. Stable transfer radiometers from the National Institute of Standards and Technology, the University of Arizona Optical Sciences Center Remote Sensing Group, NASA's Goddard Space Flight Center, and the National Research Laboratory of Metrology in Japan, have participated in these comparisons. The approaches used in the comparisons include the measurement of multiple integrating sphere lamp levels, repeat measurements of select lamp levels, the use of the stable radiometers as external sphere monitors, and the rapid reporting of measurement results. Results from several comparisons are presented. The absolute radiometric calibration standard uncertainties required by the EOS satellite instruments are typically in the +/- 3% to +/- 5% range. Preliminary results reported during eleven radiometric measurement comparisons held between February 1995 and May 1998 have shown the radiance of integrating spheres

  2. Assessment of the Short-Term Radiometric Stability between Terra MODIS and Landsat 7 ETM+ Sensors

    NASA Technical Reports Server (NTRS)

    Choi, Taeyoung; Xiong, Xiaxiong; Chander, G.; Angal, Amit

    2009-01-01

    The Landsat 7 (L7) Enhanced Thematic Mapper (ETM+) sensor was launched on April 15th, 1999 and has been in operation for over nine years. It has six reflective solar spectral bands located in the visible and shortwave infrared part of the electromagnetic spectrum (0.5 - 2.5 micron) at a spatial resolution of 30 m. The on-board calibrators are used to monitor the on-orbit sensor system changes. The ETM+ performs solar calibrations using on-board Full Aperture Solar Calibrator (FASC) and the Partial Aperture Solar Calibrator (PASC). The Internal Calibrator Lamp (IC) lamps, a blackbody and shutter optics constitute the on-orbit calibration mechanism for ETM+. On 31 May 2003, a malfunction of the scan-line corrector (SLC) mirror assembly resulted in the loss of approximately 22% of the normal scene area. The missing data affects most of the image with scan gaps varying in width from one pixel or less near the centre of the image to 14 pixels along the east and west edges of the image, creating a wedge-shaped pattern. However, the SLC failure has no impacts on the radiometric performance of the valid pixels. On December 18, 1999, the Moderate Resolution Imaging Spectroradiometer (MODIS) Proto-Flight Model (PFM) was launched on-board the NASA's EOS Terra spacecraft. Terra MODIS has 36 spectral bands with wavelengths ranging from 0.41 to 14.5 micron and collects data over a wide field of view angle (+/-55 deg) at three nadir spatial resolutions of 250 m, 500 in 1 km for bands 1 to 2, 3 to 7, and 8 to 36, respectively. It has 20 reflective solar bands (RSB) with spectral wavelengths from 0.41 to 2.1 micron. The RSB radiometric calibration is performed by using on-board solar diffuser (SD), solar diffuser stability monitor (SDSM), space-view (SV), and spectro-radiometric calibration assembly (SRCA). Through the SV port, periodic lunar observations are used to track radiometric response changes at different angles of incidence (AOI) of the scan mirror. As a part of the AM

  3. Assessment of the Short-Term Radiometric Stability between Terra MODIS and Landsat 7 ETM+ Sensors

    NASA Technical Reports Server (NTRS)

    Choi, Taeyoung; Xiong, Xiaxiong; Chander, G.; Angal, Amit

    2009-01-01

    The Landsat 7 (L7) Enhanced Thematic Mapper (ETM+) sensor was launched on April 15th, 1999 and has been in operation for over nine years. It has six reflective solar spectral bands located in the visible and shortwave infrared part of the electromagnetic spectrum (0.5 - 2.5 micron) at a spatial resolution of 30 m. The on-board calibrators are used to monitor the on-orbit sensor system changes. The ETM+ performs solar calibrations using on-board Full Aperture Solar Calibrator (FASC) and the Partial Aperture Solar Calibrator (PASC). The Internal Calibrator Lamp (IC) lamps, a blackbody and shutter optics constitute the on-orbit calibration mechanism for ETM+. On 31 May 2003, a malfunction of the scan-line corrector (SLC) mirror assembly resulted in the loss of approximately 22% of the normal scene area. The missing data affects most of the image with scan gaps varying in width from one pixel or less near the centre of the image to 14 pixels along the east and west edges of the image, creating a wedge-shaped pattern. However, the SLC failure has no impacts on the radiometric performance of the valid pixels. On December 18, 1999, the Moderate Resolution Imaging Spectroradiometer (MODIS) Proto-Flight Model (PFM) was launched on-board the NASA's EOS Terra spacecraft. Terra MODIS has 36 spectral bands with wavelengths ranging from 0.41 to 14.5 micron and collects data over a wide field of view angle (+/-55 deg) at three nadir spatial resolutions of 250 m, 500 in 1 km for bands 1 to 2, 3 to 7, and 8 to 36, respectively. It has 20 reflective solar bands (RSB) with spectral wavelengths from 0.41 to 2.1 micron. The RSB radiometric calibration is performed by using on-board solar diffuser (SD), solar diffuser stability monitor (SDSM), space-view (SV), and spectro-radiometric calibration assembly (SRCA). Through the SV port, periodic lunar observations are used to track radiometric response changes at different angles of incidence (AOI) of the scan mirror. As a part of the AM

  4. Superhydrophobic Effect on the Adsorption of Human Serum Albumin

    PubMed Central

    Leibner, Evan S.; Barnthip, Naris; Chen, Weinan; Baumrucker, Craig R.; Badding, John V.; Pishko, Michael; Vogler, Erwin A.

    2009-01-01

    Analytical protocol greatly influences measurement of human-serum albumin (HSA) adsorption to commercial expanded polytetrafluororethylene (ePTFE) exhibiting superhydrophobic wetting properties. Degassing of buffer solutions and evacuation of ePTFE adsorbent to remove trapped air immediately prior to contact with protein solutions are shown to be essential. Results obtained with ePTFE as a prototypical superhydrophobic test material suggest that vacuum degassing should be applied in the measurement of protein adsorption to any surface exhibiting superhydrophobicity. Solution depletion quantified using radiometry (I-125 labeled HSA) or electrophoresis yield different measures of adsorption, with nearly four-fold higher surface concentrations of unlabeled HSA measured by the electrophoresis method. This outcome is attributed to the influence of the radiolabel on HSA hydrophilicity which decreases radiolabeled-HSA affinity for a hydrophobic adsorbent in comparison to unlabeled HSA. These results indicate that radiometry underestimates the actual amount of protein adsorbed to a particular material. Removal of radiolabeled HSA adsorbed to ePTFE by 3X serial buffer rinses also shows that the remaining “bound fraction” was about 35% lower than the amount measured by radiometric depletion. This observation implies that measurement of protein bound after surface rinsing significantly underestimates the actual amount of protein concentrated by adsorption into the surface region of a protein-contacting material. PMID:19135420

  5. Comparison of dieldrin, lindane, and DDT extractions from serum, and gas-liquid chromatography using glass capillary columns.

    PubMed

    Franken, J J; Luyten, B J

    1976-11-01

    Rats were given an oral dose of 14C-labeled chlorinated pesticides to obtain serum containing p,p'-DDT, dieldrin, or lindane. Simple hexane and formic acid-hexane extraction methods, involving pretreatment of the serum with formic acid, were compared by radiometric and by paper chromatographic and gas chromatographic analysis. In vivo binding of chlorinated pesticides to constituents of the serum does not necessarily prohibit their isolation by simple hexane extractions, provided that the extraction is very vigorous and at least 5 min long. Stable emulsions were broken by cooling in liquid nitrogen or Dry Ice-acetone. The hexane extraction method described yields quantitative recovery of the pesticides studied, whereas the formic acid-hexane method is quantitative for p,p'-DDT, 93% for dieldrin, and 89% for lindane. Gas chromatographic comparison of both methods, using human serum, shows that the hexane method extracts 16% more beta-BHC, 7% more dieldrin and HCB, and 4% more p,p'-DDE from serum than does the formic acid-hexane method. The difference for p,p'-DDT is not significant. Gas chromatography with glass capillary columns and an all-glass solids injection system yielded detection limits as low as 15 fg. Data show that the use of an internal standard considerably improves the precision of quantitation. PMID:62748

  6. Measurement of acetol in serum.

    PubMed

    Casazza, J P; Fu, J L

    1985-08-01

    A method for the derivatization of acetol (1-hydroxyacetone) with 2,4-dinitrophenylhydrazine (DNPH) and for the measurement of the acetol dinitrophenylhydrazone derivative (acetol-DNPH) by high-performance liquid chromatography is presented. The chromatographic separation described here resulted in baseline resolution of the acetol-DNPH peak. Peak integration was proportional to serum acetol concentration over a 5- to 500-nmol/ml range. No other method for the determination of acetol in serum currently exists. Serum from rats in diabetic ketoacidosis was found to contain 11.2 +/- 1.1 nmol acetol/ml serum (N = 3). Serum from a 21-day-fasted human contained 16 nmol/ml acetol. Serum from rats maintained on drinking water containing 1% acetone (v:v) for 6 days contained 152 +/- 31 nmol/ml acetol (N = 5). The presence of acetol in serum under conditions where acetoacetate and acetone are chronically elevated suggests that acetoacetate may be converted to glucose through the conversion of acetone to acetol and L-1,2-propanediol. PMID:3933378

  7. Serum albumin: touchstone or totem?

    PubMed

    Margarson, M P; Soni, N

    1998-08-01

    A decrease in serum albumin concentrations is an almost inevitable finding in disease states, and is primarily mediated in the acute phase by alterations in vascular permeability and redistribution. This change is not disease specific but marked changes that persist are generally associated with a poorer prognosis. Critical appraisal of long-standing practices and the availability of alternative colloid solutions have led to a reduction in albumin replacement therapy, and a widespread tolerance of lower albumin concentrations in patients. The factors determining serum albumin concentrations, their measurement and the implications of hypoalbuminaemia are reviewed. The clinical value of serum albumin measurement is discussed. PMID:9797524

  8. Automatic and improved radiometric correction of Landsat imagery using reference values from MODIS surface reflectance images

    NASA Astrophysics Data System (ADS)

    Pons, X.; Pesquer, L.; Cristóbal, J.; González-Guerrero, O.

    2014-12-01

    Radiometric correction is a prerequisite for generating high-quality scientific data, making it possible to discriminate between product artefacts and real changes in Earth processes as well as accurately produce land cover maps and detect changes. This work contributes to the automatic generation of surface reflectance products for Landsat satellite series. Surface reflectances are generated by a new approach developed from a previous simplified radiometric (atmospheric + topographic) correction model. The proposed model keeps the core of the old model (incidence angles and cast-shadows through a digital elevation model [DEM], Earth-Sun distance, etc.) and adds new characteristics to enhance and automatize ground reflectance retrieval. The new model includes the following new features: (1) A fitting model based on reference values from pseudoinvariant areas that have been automatically extracted from existing reflectance products (Terra MODIS MOD09GA) that were selected also automatically by applying quality criteria that include a geostatistical pattern model. This guarantees the consistency of the internal and external series, making it unnecessary to provide extra atmospheric data for the acquisition date and time, dark objects or dense vegetation. (2) A spatial model for atmospheric optical depth that uses detailed DEM and MODTRAN simulations. (3) It is designed so that large time-series of images can be processed automatically to produce consistent Landsat surface reflectance time-series. (4) The approach can handle most images, acquired now or in the past, regardless of the processing system, with the exception of those with extremely high cloud coverage. The new methodology has been successfully applied to a series of near 300 images of the same area including MSS, TM and ETM+ imagery as well as to different formats and processing systems (LPGS and NLAPS from the USGS; CEOS from ESA) for different degrees of cloud coverage (up to 60%) and SLC

  9. A case study on bio-optical and radiometric quantities in northwest European shelf seas

    NASA Astrophysics Data System (ADS)

    Garaba, Shungu; Zielinski, Oliver

    2013-04-01

    Colour of seawater has become an integral tool in understanding surface marine ecosystems and processes. Additionally, operational oceanographic observatories are becoming more prominent these days while at the same time hyperspectral radiometric sensors are becoming increasingly affordable. This has driven a wide spread use of these hyperspectral sensors to measure reflectance above the water surface from stationary and mobile platforms alike. As enormous amounts of data are produced and favourably processed in real-time, effective quality control procedures become more than just supporting tools, but a crucial prerequisite for trustworthy and manageable information. Here, we use bio-geophysical and hyperspectral radiometric measurements from German Bight (GB), North Sea (NS), Inner Seas (ISS), Irish Sea (IS) and Celtic Sea (CS) to identify and establish relationships between colour producing agents (CPAs) and perceived colour of seawater. In order to obtain valid optical measurements, meteorological and sunglint contamination were mitigated using state-of-the-art quality control protocols. The remote sensing reflectance measured is transformed into discrete Forel-Ule numerical indices (FUI), 1 (indigo-blue, oligotrophic) to 21 (cola brown, hyper-eutrophic). We present a novel approach of estimating which of the three main CPAs of seawater control perceived colour of seawater. Our bio-optical models for estimating FUI for measured CPAs; chlorophyll (Chl-a), coloured dissolved organic material (CDOM) and suspended particulate material (SPM) had correlation coefficients, R² (GB = 0.98, NS = 0.23, ISS=0.99, IS=0.63, CS = 0.16). It was also observed that salinity can be estimated from coloured dissolved organic matter with good accuracy, R² (GB = 0.94, NS = 0.44, ISS=0.90, IS=0.85, CS = 0.51). We show that ocean colour products i.e. reflectance and perceived colour of seawater can be used to infer, with good accuracy, environmental parameters e.g. Chl-a, CDOM, SPM

  10. Radiometric Calibration of EUNIS-06 With Theoretical Predicted `Insensitive' Line Ratios

    NASA Astrophysics Data System (ADS)

    Wang, T.; Brosius, J. W.; Thomas, R. J.; Rabin, D. M.

    2007-12-01

    The Extreme-Ultraviolet Normal-Incidence Spectrograph (EUNIS) is a sounding-rocket payload that obtains imaged high-resolution spectra of solar active and quiet-Sun regions, providing information about the corona and upper transition region. EUNIS incorporates two independent, co-pointing imaging spectrographs, one covering EUV lines between 300 and 370 Å\\ seen in first order (the longwave [LW] channel), and a second covering lines between 170 and 205 Å\\ seen in second order (the shortwave [SW] channel). Shortly after the payload's initial successful flight on 2006 April 12, a complete end-to-end radiometric calibration of its LW bandpass was carried out at the Rutherford Appleton Laboratory in England. Here we develop and apply a technique for deriving the absolute radiometric calibration of its SW bandpass from these direct LW results by means of density- and temperature-insensitive line intensity ratios. The first step is to use the EUNIS LW calibration to get absolute intensities for EUV lines recorded from solar positions along its LW slit during the 2006 flight. Then co-registered SOHO/CDS images taken within minutes of the flight are used to transfer these absolute values to solar locations observed by the EUNIS SW slit, spatially offset by about 1 arcmin. Finally, theoretical `insensitive' line ratios obtained from CHIANTI allow us to determine absolute intensities of emission lines within the EUNIS SW bandpass from those observed in its LW channel. A total of 29 ratios composed of 11 LW and 15 SW emission lines from Fe~X - Fe~XIII yield an instrumental response curve that matches very well to a relative calibration which relied on combining measurements of individual optical components. The second EUNIS flight, now scheduled for 2007 October 30, will make coordinated observations and provide similar calibration updates for Hinode/EIS. We will also present some preliminary results from the new observations. EUNIS is supported by the NASA Heliophysics

  11. Parallel algorithms of relative radiometric correction for images of TH-1 satellite

    NASA Astrophysics Data System (ADS)

    Wang, Xiang; Zhang, Tingtao; Cheng, Jiasheng; Yang, Tao

    2014-05-01

    The first generation of transitive stereo-metric satellites in China, TH-1 Satellite, is able to gain stereo images of three-line-array with resolution of 5 meters, multispectral images of 10 meters, and panchromatic high resolution images of 2 meters. The procedure between level 0 and level 1A of high resolution images is so called relative radiometric correction (RRC for short). The processing algorithm of high resolution images, with large volumes of data, is complicated and time consuming. In order to bring up the processing speed, people in industry commonly apply parallel processing techniques based on CPU or GPU. This article firstly introduces the whole process and each step of the algorithm - that is in application - of RRC for high resolution images in level 0; secondly, the theory and characteristics of MPI (Message Passing Interface) and OpenMP (Open Multi-Processing) parallel programming techniques is briefly described, as well as the superiority for parallel technique in image processing field; thirdly, aiming at each step of the algorithm in application and based on MPI+OpenMP hybrid paradigm, the parallelizability and the strategies of parallelism for three processing steps: Radiometric Correction, Splicing Pieces of TDICCD (Time Delay Integration Charge-Coupled Device) and Gray Level Adjustment among pieces of TDICCD are deeply discussed, and furthermore, deducts the theoretical acceleration rates of each step and the one of whole procedure, according to the processing styles and independence of calculation; for the step Splicing Pieces of TDICCD, two different strategies of parallelism are proposed, which are to be chosen with consideration of hardware capabilities; finally, series of experiments are carried out to verify the parallel algorithms by applying 2-meter panchromatic high resolution images of TH-1 Satellite, and the experimental results are analyzed. Strictly on the basis of former parallel algorithms, the programs in the experiments

  12. Gravity, magnetic, and radiometric data for Newberry Volcano, Oregon, and vicinity

    USGS Publications Warehouse

    Wynn, Jeff

    2014-01-01

    Newberry Volcano in central Oregon is a 3,100-square-kilometer (1,200-square-mile) shield-shaped composite volcano, occupying a location east of the main north-south trend of the High Cascades volcanoes and forming a transition between the High Lava Plains subprovince of the Basin and Range Province to the east and the Cascade Range to the west. Magnetic, gravity, and radiometric data have been gathered and assessed for the region around the volcano. These data have widely varying quality and resolution, even within a given dataset, and these limitations are evaluated and described in this release. Publicly available gravity data in general are too sparse to permit detailed modeling except along a few roads with high-density coverage. Likewise, magnetic data are also unsuitable for all but very local modeling, primarily because available data consist of a patchwork of datasets with widely varying line-spacing. Gravity data show only the broadest correlation with mapped geology, whereas magnetic data show moderate correlation with features only in the vicinity of Newberry Caldera. At large scales, magnetic data correlate poorly with both geologic mapping and gravity data. These poor correlations are largely due to the different sensing depths of the two potential fields methods, which respond to physical properties deeper than the surficial geology. Magnetic data derive from rocks no deeper than the Curie-point isotherm depth (10 to 15 kilometers, km, maximum), whereas gravity data reflect density-contrasts to 100 to 150 km depths. Radiometric data from the National Uranium Resource Evaluation (NURE) surveys of the 1980s have perhaps the coarsest line-spacing of all (as much as 10 km between lines) and are extremely “noisy” for several reasons inherent to this kind of data. Despite its shallow-sensing character, only a few larger anomalies in the NURE data correlate well with geologic mapping. The purpose of this data series release is to collect and place the

  13. Making SAR Data Accessible - ASF's ALOS PALSAR Radiometric Terrain Correction Project

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; Arko, S. A.; Gens, R.

    2015-12-01

    While SAR data have proven valuable for a wide range of geophysical research questions, so far, largely only the SAR-educated science communities have been able to fully exploit the information content of internationally available SAR archives. The main issues that have been preventing a more widespread utilization of SAR are related to (1) the diversity and complexity of SAR data formats, (2) the complexity of the processing flows needed to extract geophysical information from SAR, (3) the lack of standardization and automation of these processing flows, and (4) the often ignored geocoding procedures, leaving the data in image coordinate space. In order to improve upon this situation, ASF's radiometric terrain-correction (RTC) project is generating uniformly formatted and easily accessible value-added products from the ASF Distributed Active Archive Center's (DAAC) five-year archive of JAXA's ALOS PALSAR sensor. Specifically, the project applies geometric and radiometric corrections to SAR data to allow for an easy and direct combination of obliquely acquired SAR data with remote sensing imagery acquired in nadir observation geometries. Finally, the value-added data is provided to the user in the broadly accepted Geotiff format, in order to support the easy integration of SAR data into GIS environments. The goal of ASF's RTC project is to make SAR data more accessible and more attractive to the broader SAR applications community, especially to those users that currently have limited SAR expertise. Production of RTC products commenced October 2014 and will conclude late in 2015. As of July 2015, processing of 71% of ASF's ALOS PALSAR archive was completed. Adding to the utility of this dataset are recent changes to the data access policy that allow the full-resolution RTC products to be provided to the public, without restriction. In this paper we will introduce the processing flow that was developed for the RTC project and summarize the calibration and validation

  14. Signature modelling and radiometric rendering equations in infrared scene simulation systems

    NASA Astrophysics Data System (ADS)

    Willers, Cornelius J.; Willers, Maria S.; Lapierre, Fabian

    2011-11-01

    The development and optimisation of modern infrared systems necessitates the use of simulation systems to create radiometrically realistic representations (e.g. images) of infrared scenes. Such simulation systems are used in signature prediction, the development of surveillance and missile sensors, signal/image processing algorithm development and aircraft self-protection countermeasure system development and evaluation. Even the most cursory investigation reveals a multitude of factors affecting the infrared signatures of realworld objects. Factors such as spectral emissivity, spatial/volumetric radiance distribution, specular reflection, reflected direct sunlight, reflected ambient light, atmospheric degradation and more, all affect the presentation of an object's instantaneous signature. The signature is furthermore dynamically varying as a result of internal and external influences on the object, resulting from the heat balance comprising insolation, internal heat sources, aerodynamic heating (airborne objects), conduction, convection and radiation. In order to accurately render the object's signature in a computer simulation, the rendering equations must therefore account for all the elements of the signature. In this overview paper, the signature models, rendering equations and application frameworks of three infrared simulation systems are reviewed and compared. The paper first considers the problem of infrared scene simulation in a framework for simulation validation. This approach provides concise definitions and a convenient context for considering signature models and subsequent computer implementation. The primary radiometric requirements for an infrared scene simulator are presented next. The signature models and rendering equations implemented in OSMOSIS (Belgian Royal Military Academy), DIRSIG (Rochester Institute of Technology) and OSSIM (CSIR & Denel Dynamics) are reviewed. In spite of these three simulation systems' different application focus

  15. Aerosol, cloud, and radiometric measurements with small autonomous unmanned aerial vehicles

    NASA Astrophysics Data System (ADS)

    Ramanathan, V.; Roberts, G.; Corrigan, C.; Ramana, M.; Nguyen, H.

    2005-12-01

    The AUAV (autonomous unmanned aerial vehicle) project is a part of the Atmospheric Brown Clouds project. It has been designed to allow for routine vertical profile measurements of aerosols and clouds using AUAVs above ground-based observatories in the Indo-Pacific Ocean region. The current scientific payloads consist of optical particle counters, condensation particle counters, cloud droplet probes, aethelometers, upward and downward facing pyranometers, and temperature-relative humidity sensors. Aerosol, cloud and radiometric instruments have been miniaturized with a total payload weight and power less than 5 kg and 50 W, respectively. Demonstration flights at the Yuma Proving Grounds, AZ show the potential for small AUAVs in atmospheric studies. The flights were performed on two aircraft, which flew autonomously up to 3000 m above sea level (asl) along programmed flight tracks. The aircraft flew in stacked formation for part of the flights. Once the aircraft were stacked (550 and 2100 m asl), the projected distances were less than 50 m - which translates to less than a 1.5 sec latency between the aircraft. Vertical profiles show a constant 8 K km-1 lapse rate and increasing relative humidity with altitude. At 2000 m asl (1600 m above ground level), an aerosol layer is evident in the total aerosol concentration profile (NCN = 2000 cm-3); relative humidity also increased by 10% in this layer. No such increase in 0.3 μm aerosol (NOPC) is visible at 2000 m asl, suggesting transport from an urban center. Back trajectories indicate air masses originated from south and west across central Baja California, Mexico. Aerosol concentrations are fairly constant at 1000 cm-3 throughout the profile indicating a well-mixed boundary layer. Spikes in aerosol concentrations are a result of sampling the aircrafts' exhaust. The vertical profiles show that spikes occurred at levels where the aircraft maintained level, repeating holding patterns. The cloud droplet probe was flown

  16. Review of Terra MODIS thermal emissive band L1B radiometric performance

    NASA Astrophysics Data System (ADS)

    Moeller, Chris; Menzel, W. P.; Quinn, Greg

    2014-09-01

    The MODerate-resolution Imaging Spectroradiometer (MODIS) on NASA's Earth Observing System Terra satellite, launched into orbit on 18 December 1999, will have a "first light" 15th anniversary on 24 February 2015. For nearly 15 years the MODIS instrument has provided radiances in all spectral bands. Though some detectors have fallen below SNR thresholds, the vast majority of spectral bands continue to provide high quality L1B measurements for use in L2 science algorithms supporting global climate research. Radiometric accuracy of the Terra MODIS thermal emissive bands (TEBs) in the C6 L1B product has been assessed using various approaches over the nearly 15 year Terra MODIS data record, including comparisons with instruments on the ground, in aircraft under-flights, and on other satellites. All of these approaches contribute to the understanding of the Terra MODIS radiometric L1B performance. Early in the lifetime of Terra, ground-based measurements and NASA ER-2 aircraft under-flights revealed that TEBs in the infrared window ("window" bands) are well calibrated and performing within accuracy specifications. The ER-2 under-flights also suggested that many atmospheric bands may be performing outside of specification, especially LWIR CO2 sensitive bands that are subject to optical crosstalk, although analysis uncertainties are larger for atmospheric bands. Beginning in 2007, MetOp-A IASI observations were used to evaluate Terra MODIS TEB performance through Simultaneous Nadir Overpass (SNO) comparisons. These inter-satellite comparisons largely affirm the early aircraft and ground-based evaluations, showing that all Terra MODIS window bands have small biases, minimal trending, and minor detector and mirror side striping over the 2007-2013 timeframe. Most atmospheric bands are performing satisfactorily near to specification; however, biases, striping and trending are large and significantly out of specification in the water vapor sensitive band 27 and ozone sensitive

  17. Evaluating AIRS Radiometric Error in Non-uniform Scenes using MODIS

    NASA Astrophysics Data System (ADS)

    Pagano, T. S.; Aumann, H. H.

    2014-12-01

    The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in 2378 channels ranging in wavelength from 3.7-15.4 um with spectral resolution of better than 1200, and spatial resolution of 13.5 km with global daily coverage. The AIRS was designed to measure temperature and water vapor profiles for improvement in weather forecast and improved parameterization of climate processes. Currently the AIRS Level 1B Radiance Products are assimilated by NWP centers worldwide and have shown considerable forecast improvement. AIRS L1 and L2 products are widely used for studying critical climate processes related to water vapor feedback, atmospheric transport and cloud properties. AIRS trace gas products include ozone profiles, carbon monoxide, and the first global maps of mid-tropospheric carbon dioxide. The AIRS radiances are calibrated using a uniform on-board blackbody and full aperture space view. For this reason, all radiometric measurements assume a uniform scene. As with most instruments, the AIRS 2D spatial response functions (tophat functions) are not flat for all channels, nor are they the same. When viewing a non-uniform scene, this causes a radiometric error that is scene dependent and cannot be removed without knowledge of the scene response. The magnitude of the error depends on the non-uniformity of the AIRS spatial response and the non-uniformity of the scene, but typically only affects about 1% of the data. In this effort we use data from the MODIS instrument to provide information on the scene uniformity that can be used to correct the AIRS data. Early results show we can match the AIRS and MODIS radiances to about 0.6K when we include the AIRS tophat functions in the normalization of the MODIS data (Elliott, Proc SPIE 6296, 2006). The method requires use of different infrared bands in MODIS depending on the channels of AIRS being corrected. Resulting improvement in noise and

  18. Sensitive detection of C-reactive protein in serum by immunoprecipitation-microchip capillary gel electrophoresis.

    PubMed

    Herwig, Ela; Marchetti-Deschmann, Martina; Wenz, Christian; Rüfer, Andreas; Redl, Heinz; Bahrami, Soheyl; Allmaier, Günter

    2015-06-01

    Sepsis represents a significant cause of mortality in intensive care units. Early diagnosis of sepsis is essential to increase the survival rate of patients. Among others, C-reactive protein (CRP) is commonly used as a sepsis marker. In this work we introduce immune precipitation combined with microchip capillary gel electrophoresis (IP-MCGE) for the detection and quantification of CRP in serum samples. First high-abundance proteins (HSA, IgG) are removed from serum samples using affinity spin cartridges, and then the remaining proteins are labeled with a fluorescence dye and incubated with an anti-CRP antibody, and the antigen/antibody complex is precipitated with protein G-coated magnetic beads. After precipitation the complex is eluted from the beads and loaded onto the MCGE system. CRP could be reliably detected and quantified, with a detection limit of 25 ng/μl in serum samples and 126 pg/μl in matrix-free samples. The overall sensitivity (LOQ = 75 ng/μl, R(2) = 0.9668) of the method is lower than that of some specially developed methods (e.g., immune radiometric assay) but is comparable to those of clinically accepted ELISA methods. The straightforward sample preparation (not prone to mistakes), reduced sample and reagent volumes (including the antibodies), and high throughput (10 samples/3 h) are advantages and therefore IP-MCGE bears potential for point-of-care diagnosis. PMID:25778394

  19. Correction to Method of Establishing the Absolute Radiometric Accuracy of Remote Sensing Systems While On-orbit Using Characterized Stellar Sources

    NASA Technical Reports Server (NTRS)

    Bowen, Howard S.; Cunningham, Douglas M.

    2007-01-01

    The contents include: 1) Brief history of related events; 2) Overview of original method used to establish absolute radiometric accuracy of remote sensing instruments using stellar sources; and 3) Considerations to improve the stellar calibration approach.

  20. Evaluation of the Radiometric Quality of the TM Data Using Clustering, Linear Transformations and Multispectral Distance Measures. [Illinois

    NASA Technical Reports Server (NTRS)

    Bartolucci, L. A.; Dean, M. E.; Anuta, P. E.

    1985-01-01

    The radiometric quality of LANDSAT 4 TM data for the classification and identification of Earth surface features was evaluated. Techniques employed in the evaluation included clustering, data compression (linear transformations), multispectral distance measures, and hierarchical classification methods. TM and MSS data for the Chicago, Illinois test site were studied. In order to determine the radiometric quality of the TM thermal data for temperature mapping of surface water, a test site was selected within the area covered by the TM scene (Scene ID: 40101-16025) gathered over Illinois. This site was chosen because it includes a surface water body with a large range of temperatures, i.e., a cooling pond for the Dresden nuclear power plant and the junction of two rivers.

  1. 225-GHz atmospheric opacity of the South Pole sky derived from continual radiometric measurements of the sky-brightness temperature.

    PubMed

    Chamberlin, R A; Bally, J

    1994-02-20

    We report measurements of the atmospheric opacity of the South Pole at 225 GHz for the period from day 3 to day 180 in 1992. These opacity data were derived from continual radiometric measurements of the sky-brightness temperature as a function of the zenith angle. These radiometric measurements were performed with a 225-GHz heterodyne atmospheric radiometer on loan from the National Radio Astronomy Observatory. This radiometer was previously used to characterize other candidate millimeter and submillimeter radio-telescope sites. We found that the atmospheric opacity was below 0.098 air mass(-1) 75% of the time from day 3 to day 70 in 1992, and below 0.055 air mass(-1) 75% of the time from day 70 to day 180 in 1992. Thus, our data demonstrate that the South Pole is an excellent site for performing millimeter-and submillimeter-wavelength radio astronomy. PMID:20862122

  2. Validation of the onboard radiometric calibration of the GOES I-M visible channel by reflectance-based vicarious methods

    NASA Astrophysics Data System (ADS)

    Leisso, Nathan P.; Thome, Kurtis J.; Czapla-Myers, Jeffrey S.

    2007-09-01

    The current generation of the Geostationary Operations Environmental Satellite (GOES) platform employs a total of 5 sensors to monitor and record atmospheric conditions used in predictions of upcoming weather events. Included in this package is a 5-band imager that, from the 36,000-km geosynchronous orbit inhabited by GOES platform, enables multiple fixed full-disc surface images of the earth during the course of a 24-hour day. There is currently no on-board radiometric calibration for the visible bands of the imager and radiometric calibration relies on vicarious approaches. The Remote Sensing Group (RSG) at the University of Arizona uses a vicarious approach that relies on ground-based measurements to determine the radiometric calibration for multiple sun-synchronous and airborne visible and near-infrared sensors. The current work extends the approach to the GOES I-M series of sensor. The paper presents the methods and results of the reflectance-based method applied to the 1-km visible channel of GOES-11using large North American high-desert test sites. Modifications to the RSG's methods to take into account the location of the test sites at large zenith angles within the full-disk GOES image. The work provides an opportunity to evaluate uncertainties of the spectral BRF of the test sites at large view angles and resulting importance to the accurate radiometric calibration of a sensor. In addition, the impact of increased path length caused by the large view angle is evaluated with an emphasis on the increased effect of the atmospheric characterization.

  3. Orbit Determination and Gravity Field Estimation of the Dawn spacecraft at Vesta Using Radiometric and Image Constraints with GEODYN Software

    NASA Astrophysics Data System (ADS)

    Centinello, F. J.; Zuber, M. T.; Mazarico, E.

    2013-12-01

    The Dawn spacecraft orbited the protoplanet Vesta from May 3, 2011 to July 25, 2012. Precise orbit determination was critical for the geophysical investigation, as well as the definition of the Vesta-fixed reference frame and the subsequent registration of datasets to the surface. GEODYN, the orbit determination and geodetic parameter estimation software of NASA Goddard Spaceflight Center, was used to compute the orbit of the Dawn spacecraft and estimate the gravity field of Vesta. GEODYN utilizes radiometric Doppler and range measurements, and was modified to process image data from Dawn's cameras. X-band radiometric measurements were acquired by the NASA Deep Space Network (DSN). The addition of the capability to process image constraints decreases position uncertainty in the along- and cross-orbit track directions because of their geometric strengths compared with radiometric measurements. This capability becomes critical for planetary missions such as Dawn due to the weak gravity environment, where non-conservative forces affect the orbit more than typical of orbits at larger planetary bodies. Radiometric measurements were fit to less than 0.1 mm/s and 5 m for Doppler and range during the Survey orbit phase (compared with measurement noise RMS of about 0.05 mm/s and 2 m for Doppler and range). Image constraint RMS was fit to less than 100 m (resolution is 5 - 150 m/pixel, depending on the spacecraft altitude). Orbits computed using GEODYN were used to estimate a 20th degree and order gravity field of Vesta. The quality of the orbit determination and estimated gravity field with and without image constraints was assessed through comparison with the spacecraft trajectory and gravity model provided by the Dawn Science Team.

  4. A definitive calibration record for the Landsat-5 thematic mapper anchored to the Landsat-7 radiometric scale

    USGS Publications Warehouse

    Teillet, P.M.; Helder, D.L.; Ruggles, T.A.; Landry, R.; Ahern, F.J.; Higgs, N.J.; Barsi, J.; Chander, G.; Markham, B.L.; Barker, J.L.; Thome, K.J.; Schott, J.R.; Palluconi, Frank Don

    2004-01-01

    A coordinated effort on the part of several agencies has led to the specification of a definitive radiometric calibration record for the Landsat-5 thematic mapper (TM) for its lifetime since launch in 1984. The time-dependent calibration record for Landsat-5 TM has been placed on the same radiometric scale as the Landsat-7 enhanced thematic mapper plus (ETM+). It has been implemented in the National Landsat Archive Production Systems (NLAPS) in use in North America. This paper documents the results of this collaborative effort and the specifications for the related calibration processing algorithms. The specifications include (i) anchoring of the Landsat-5 TM calibration record to the Landsat-7 ETM+ absolute radiometric calibration, (ii) new time-dependent calibration processing equations and procedures applicable to raw Landsat-5 TM data, and (iii) algorithms for recalibration computations applicable to some of the existing processed datasets in the North American context. The cross-calibration between Landsat-5 TM and Landsat-7 ETM+ was achieved using image pairs from the tandem-orbit configuration period that was programmed early in the Laridsat-7 mission. The time-dependent calibration for Landsat-5 TM is based on a detailed trend analysis of data from the on-board internal calibrator. The new lifetime radiometric calibration record for Landsat-5 will overcome problems with earlier product generation owing to inadequate maintenance and documentation of the calibration over time and will facilitate the quantitative examination of a continuous, near-global dataset at 30-m scale that spans almost two decades.

  5. The Global Earth Observation System of Systems (GEOSS) and metrological support for measuring radiometric properties of objects of observations

    NASA Astrophysics Data System (ADS)

    Krutikov, V. N.; Sapritsky, V. I.; Khlevnoy, B. B.; Lisiansky, B. E.; Morozova, S. P.; Ogarev, S. A.; Panfilov, A. S.; Sakharov, M. K.; Samoylov, M. L.; Bingham, G.; Humpherys, T.; Thurgood, A.; Privalsky, V. E.

    2006-04-01

    The international Global Earth Observation System of Systems is at its initial stage. We present some general information about the program and formulate the task of ensuring the uniformity of radiometric measurements to be conducted by all the participating national systems. Methods of solving the task are suggested on the basis of the wide application of standard sources that use phase transition of eutectic alloys and pure metals as well as with the help of improved ground calibration facilities.

  6. Serum Uric Acid in Smokers

    PubMed Central

    Hanna, Bassam E.; Hamed, Jamal M.; Touhala, Luma M.

    2008-01-01

    Objectives To demonstrate the possible effect of smoking on serum uric acid. Methods Subjects enrolled in study were divided into two groups; nonsmokers and smokers, each with 60 male volunteers of the same social class and dietary habit without history of alcohol consumption, diabetes mellitus, hyperuricemia and gout, renal, joint, lung or heart diseases. Fasting blood and random urine samples were obtained from both groups for measurement of uric acid and creatinine. Calculation of both urine uric acid/urine creatinine ratio and fraction excretion of uric acid were done. The results were statistically evaluated by standard statistical methods. Results No significant differences in the age, serum creatinine, spot urine uric acid/urine creatinine ratio and fraction excretion of uric acid between the two groups, serum uric acid was significantly lower in smokers. In smokers there was significant negative correlation of smoking status (average number of cigarette smoked/day, duration of smoking and cumulative amount of smoking) with serum uric acid. Conclusion After exclusion of other factors affecting uric acid level, the significant low serum uric acid level in smokers was attributed to reduce endogenous production as a result of chronic exposure to cigarette smoke that is a significant source of oxidative stress. As this reduction is proportionate with smoking status and predisposes to cardiovascular disease, it is, therefore, recommended for smokers to stop or reduce smoking and introduce serum uric acid estimation as routine test since its cheap and simple to reflect their antioxidant level. Keywords Smokers; Uric acid; CVD. PMID:22334840

  7. Effect of radiometric errors on accuracy of temperature-profile measurement by spectral scanning using absorption-emission pyrometry

    NASA Technical Reports Server (NTRS)

    Buchele, D. R.

    1972-01-01

    The spectral-scanning method may be used to determine the temperature profile of a jet- or rocket-engine exhaust stream by measurements of gas radiation and transmittance, at two or more wavelengths. A single, fixed line of sight is used, using immobile radiators outside of the gas stream, and there is no interference with the flow. At least two sets of measurements are made, each set consisting of the conventional three radiometric measurements of absorption-emission pyrometry, but each set is taken over a different spectral interval that gives different weight to the radiation from a different portion of the optical path. Thereby, discrimination is obtained with respect to location along the path. A given radiometric error causes an error in computed temperatures. The ratio between temperature error and radiometric error depends on profile shape, path length, temperature level, and strength of line absorption, and the absorption coefficient and its temperature dependency. These influence the choice of wavelengths, for any given gas. Conditions for minimum temperature error are derived. Numerical results are presented for a two-wavelength measurement on a family of profiles that may be expected in a practical case of hydrogen-oxygen combustion. Under favorable conditions, the fractional error in temperature approximates the fractional error in radiant-flux measurement.

  8. Vesicoureteral reflux in young children: a study of radiometric thermometry as detection modality using an ex vivo porcine model

    NASA Astrophysics Data System (ADS)

    Jacobsen, Svein; Klemetsen, Øystein; Birkelund, Yngve

    2012-09-01

    Microwave radiometry is evaluated for renal thermometry tailored to detect the pediatric condition of vesicoureteral urine reflux (VUR) from the bladder through the ureter into the kidney. Prior to a potential reflux event, the urine is heated within the bladder by an external body contacting a hyperthermia applicator to generate a fluidic contrast temperature relative to normal body temperature. A single band, miniaturized radiometer (operating at 3.5 GHz) is connected to an electromagnetic-interference-shielded and suction-coupled elliptical antenna to receive thermal radiation from an ex vivo porcine phantom model. Brightness (radiometric) and fiberoptic temperature data are recorded for varying urine phantom reflux volumes (20-40 mL) and contrast temperatures ranging from 2 to 10 °C within the kidney phantom. The kidney phantom itself is located at 40 mm depth (skin-to-kidney center distance) and surrounded by the porcine phantom. Radiometric step responses to injection of urine simulant by a syringe are shown to be highly correlated with in situ kidney temperatures measured by fiberoptic probes. Statistically, the performance of the VUR detecting scheme is evaluated by error probabilities of making a wrong decision. Laboratory testing of the radiometric system supports the feasibility of passive non-invasive kidney thermometry for the detection of VUR classified within the two highest grades

  9. Vesicoureteral reflux in young children: a study of radiometric thermometry as detection modality using an ex vivo porcine model.

    PubMed

    Jacobsen, Svein; Klemetsen, Øystein; Birkelund, Yngve

    2012-09-01

    Microwave radiometry is evaluated for renal thermometry tailored to detect the pediatric condition of vesicoureteral urine reflux (VUR) from the bladder through the ureter into the kidney. Prior to a potential reflux event, the urine is heated within the bladder by an external body contacting a hyperthermia applicator to generate a fluidic contrast temperature relative to normal body temperature. A single band, miniaturized radiometer (operating at 3.5 GHz) is connected to an electromagnetic-interference-shielded and suction-coupled elliptical antenna to receive thermal radiation from an ex vivo porcine phantom model. Brightness (radiometric) and fiberoptic temperature data are recorded for varying urine phantom reflux volumes (20-40 mL) and contrast temperatures ranging from 2 to 10 °C within the kidney phantom. The kidney phantom itself is located at 40 mm depth (skin-to-kidney center distance) and surrounded by the porcine phantom. Radiometric step responses to injection of urine simulant by a syringe are shown to be highly correlated with in situ kidney temperatures measured by fiberoptic probes. Statistically, the performance of the VUR detecting scheme is evaluated by error probabilities of making a wrong decision. Laboratory testing of the radiometric system supports the feasibility of passive non-invasive kidney thermometry for the detection of VUR classified within the two highest grades. PMID:22892477

  10. Retrieval of Total Precipitable Water over High-Latitude Regions Using Radiometric Measurements near 90 and 183 GHz.

    NASA Astrophysics Data System (ADS)

    Wang, J. R.; Boncyk, W. C.; Dod, L. R.; Sharma, A. K.

    1992-12-01

    Radiometric measurements at 90 GHz and three sideband frequencies near the peak water vapor absorption line of 183.3 GHz were made with Advanced Microwave Moisture Sounder (AMMS) aboard the NASA DC-8 aircraft during the Global Aerosol Backscatter Experiment (GLOBE) mission over the Pacific Ocean in November 1989. Some of the measurements over the high-latitude regions (>50°N or 50°S) were analyzed for the retrieval of total precipitable water less than 0.5 g cm2 both over land and ocean surfaces. The results show that total precipitable water from a relatively dry atmosphere could be estimated with high sensitivity from these radiometric measurements. The retrieved values over ocean surface show a decrease toward the polar region as expected. The retrieved total precipitable water over land correlates positively with the aircraft radar altitude. This positive correlation is expected because the aircraft radar altitude provides a measure of atmospheric water vapor burden above the surface. Retrieved high reflectivities over land surface at 90 GHz and 183 GHz are presumably related to snow cover on the ground. This suggests that radiometric measurements at these frequencies could be used to map snow at high-latitude regions.

  11. Radiometric Calibration of the AWiFS Sensor and a Cross-calibration Enhanced Vicarious Calibration Technique

    NASA Technical Reports Server (NTRS)

    Aaron, David

    2007-01-01

    Using vicarious calibration validation of moderate resolution sensors such as AWiFS is complicated by requiring more land area to ensure proper registration and sufficient pixel numbers. A trial AWiFS calibration was performed on a grass site that consisted of two dramatically different grass heights. Ground truth data was collected over relatively small areas representing only a few pixels. The radiometric gain results for each of these areas will be reported. To enhance this analysis, since a near coincidence high resolution image was collected, the high resolution data was effectively resized to produce pixels comparable to AWiFS and the atmospheric model was used to produce a top of canopy radiance map. Multiple uniform vegetated areas of several radiances were then identified and subsequently propagated to the top of atmosphere viewpoint of the moderate resolution (AWiFS) satellite. The radiometric gain was then calculated based on the vendor high resolution satellite gains (for the 3 bands with comparable wavelengths). Band-to-band conversion was performed assuming a hyperspectral reflectance based on the standard vegetated site. The initial comparison produces AWiFS radiometric gain values that agree to better than 10% of the values measured using the standard vicarious gain technique.

  12. Reflectance-based radiometric calibration of multispectral Earth-observation sensors using an automated test site at Railroad Valley, Nevada

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, J.; Leisso, N. P.

    2011-12-01

    Ground-based vicarious radiometric calibration is used as an independent source to monitor the temporal changes in Earth-observing sensors. The Remote Sensing Group at the University of Arizona uses the reflectance-based approach, which requires in-situ measurements of surface reflectance and atmospheric properties during a sensor overpass. The group has expanded its capabilities by developing the Radiometric Calibration Test Site (RadCaTS), which operates in the absence of ground personnel at Railroad Valley, Nevada. It is comprised of ground-viewing radiometers, which are used to determine the surface reflectance, and a Cimel Sun photometer, which is used to make atmospheric measurements. The radiative transfer code MODTRAN5 is used to determine the top-of-atmosphere spectral radiance for a given overpass. This work presents radiometric calibration results for MODIS, MISR, ASTER, and Landsat 7 ETM+, which were obtained using RadCaTS. The automated results are also compared to those obtained using in-situ techniques.

  13. Radiometric calibration of GOSAT TANSO-FTS SWIR bands: comparison of vicarious to on-orbit results

    NASA Astrophysics Data System (ADS)

    Taylor, T. E.; O'Dell, C.; O'Brien, D. M.; Kataoka, F.; Kuze, A.; Bruegge, C.

    2012-12-01

    The Thermal And Near-infrared Sensor for carbon Observation - Fourier Transform Spectrometer (TANSO-FTS) aboard the Greenhouse gases Observing SATellite (GOSAT) has been providing global, space-based measurements of solar reflected radiances since early 2009. Several operational or semi-operational algorithms exist to invert the measured radiances, producing column-averaged carbon dioxide (CO2) dry air mole fraction (XCO2). The resulting XCO2 are used as inputs to flux inversion models to determine sources and sinks of CO2. An accurate radiometric calibration of the TANSO-FTS short wave infrared (SWIR) channels is required in order to yield results with high accuracy. In this work we summarize the latest estimation of ground-based vicarious calibration coefficients (VCC) from four separate field campaigns conducted at the Railroad Valley playa in June of 2009-2012. We then provide a comparison of the time-dependent VCC with the results from the radiometric calibration performed using on-orbit solar observations. While both approaches indicate some radiometric degradation in the SWIR bands, with the strongest decay in the Oxygen-A band, the magnitude of the changes disagree.

  14. Atmospheric measurement analysis for the Radiometric Calibration Test Site (RadCaTS)

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, Jeffrey

    2015-09-01

    The Radiometric Calibration Test Site (RadCaTS) was developed by the University of Arizona in the early 2000s to collect ground-based data in support of the calibration and validation of Earth-observing sensors. It uses the reflectance-based approach, which requires measurements of the atmosphere and surface reflectance. The measurements are used in MODTRAN to determine the at-sensor radiance for a given time and date. In the traditional reflectance-based approach, on-site personnel use an automated solar radiometer (ASR) to measure the atmospheric attenuation, but in the case of RadCaTS, an AERONET Cimel sun photometer is used to make atmospheric measurements. This work presents a comparison between the Cimel-derived atmospheric characteristics such as aerosol optical depth, the Angstrom exponent, and the columnar water vapor, to those derived using a traditional solar radiometer. The top-of-atmosphere radiance derived using the Cimel and ASR measurements are compared using Landsat 8 OLI bands as a test case for the period 2012-2014 to determine if any biases exist between the two methodologies.

  15. Multispectral scanner flight model (F-1) radiometric calibration and alignment handbook

    NASA Technical Reports Server (NTRS)

    1981-01-01

    This handbook on the calibration of the MSS-D flight model (F-1) provides both the relevant data and a summary description of how the data were obtained for the system radiometric calibration, system relative spectral response, and the filter response characteristics for all 24 channels of the four band MSS-D F-1 scanner. The calibration test procedure and resulting test data required to establish the reference light levels of the MSS-D internal calibration system are discussed. The final set of data ("nominal" calibration wedges for all 24 channels) for the internal calibration system is given. The system relative spectral response measurements for all 24 channels of MSS-D F-1 are included. These data are the spectral response of the complete scanner, which are the composite of the spectral responses of the scan mirror primary and secondary telescope mirrors, fiber optics, optical filters, and detectors. Unit level test data on the measurements of the individual channel optical transmission filters are provided. Measured performance is compared to specification values.

  16. Radiometric analysis of the longwave infrared channel of the Thematic Mapper on LANDSAT 4 and 5

    NASA Technical Reports Server (NTRS)

    Schott, John R.; Volchok, William J.; Biegel, Joseph D.

    1986-01-01

    The first objective was to evaluate the postlaunch radiometric calibration of the LANDSAT Thematic Mapper (TM) band 6 data. The second objective was to determine to what extent surface temperatures could be computed from the TM and 6 data using atmospheric propagation models. To accomplish this, ground truth data were compared to a single TM-4 band 6 data set. This comparison indicated satisfactory agreement over a narrow temperature range. The atmospheric propagation model (modified LOWTRAN 5A) was used to predict surface temperature values based on the radiance at the spacecraft. The aircraft data were calibrated using a multi-altitude profile calibration technique which had been extensively tested in previous studies. This aircraft calibration permitted measurement of surface temperatures based on the radiance reaching the aircraft. When these temperature values are evaluated, an error in the satellite's ability to predict surface temperatures can be estimated. This study indicated that by carefully accounting for various sensor calibration and atmospheric propagation effects, and expected error (1 standard deviation) in surface temperature would be 0.9 K. This assumes no error in surface emissivity and no sampling error due to target location. These results indicate that the satellite calibration is within nominal limits to within this study's ability to measure error.

  17. Revisiting the NEAR mission with radiometric, altimetric and image tracking data

    NASA Astrophysics Data System (ADS)

    Mazarico, Erwan; Neumann, Gregory; Rowlands, David; Barnouin, Olivier

    2014-05-01

    The NEAR mission to asteroid 433 Eros in 2000-2001 was the first extended survey of an asteroid. In orbit around Eros for about one year, NEAR acquired a wealth of global and high-resolution data about this Near-Earth Asteroid. The primary geodetic dataset is the radiometric tracking data collected by the NASA Deep Space Network, which have been used to reconstruct the orbits of multiple planetary orbiter missions and determine the gravity field of their target body. However, given the small size of Eros compared to terrestrial bodies, the gravitational environment is relatively weak, and the constraints from Doppler data are not as strong. Altimetric data from the NLR instrument, in the form of altimetric crossovers, were used by the NLR team to support the radio data. Image-based constraints, such as landmark data, were used by the navigation team to provide out-of-plane orbital information. Here, we process the three types of measurements simultaneously. We use the altimetric data not as crossovers, but as direct shot-to-shot distance constraints. We implemented in our GEODYN software both the landmark data type and a constraint on the geometry of image pairs which does not rely on prior accurate knowledge of surface point locations. We present results from this analysis, in terms of spacecraft orbits, gravity field and orientation solution, and shape of 433 Eros.

  18. Utility of Assimilating Surface Radiometric Temperature Observations for Evaporative Fraction and Heat Transfer Coefficient Retrieval

    NASA Astrophysics Data System (ADS)

    Crow, Wade T.; Kustas, William P.

    2005-04-01

    Recent advances in land data assimilation have yielded variational smoother techniques designed to solve the surface energy balance based on remote observations of surface radiometric temperature. These approaches have a number of potential advantages over existing diagnostic models, including the ability to make energy flux predictions between observation times and reduced requirements for ancillary parameter estimation. Here, the performance of a recently developed variational smoother approach is examined in detail over a range of vegetative and hydrological conditions in the southern U.S.A. during the middle part of the growing season. Smoother results are compared with flux tower observations and energy balance predictions obtained from the two-source energy balance model (TSM). The variational approach demonstrates promise for flux retrievals at dry and lightly vegetated sites. However, results suggest that the simultaneous retrieval of both evaporative fraction and turbulent transfer coefficients by the variational approach will be difficult for wet and/or heavily vegetated land surfaces. Additional land surface information (e.g. leaf area index ( L AI) or the rough specification of evaporative fraction bounds) will be required to ensure robust predictions under such conditions. The single-source nature of the variational approach also hampers the physical interpretation of turbulent transfer coefficient retrievals. Intercomparisons between energy flux predictions from the variational approach and the purely diagnostic TSM demonstrate that the relative accuracy of each approach is contingent on surface conditions and the accuracy with which L AI values required by the TSM can be estimated.

  19. Radiometric ratio characterization for low-to-mid CPV modules operating in variable irradiance conditions

    NASA Astrophysics Data System (ADS)

    Vorndran, Shelby; Russo, Juan; Zhang, Deming; Gordon, Michael; Kostuk, Raymond

    2012-10-01

    In this work, a concentrating photovoltaic (CPV) design methodology is proposed which aims to maximize system efficiency for a given irradiance condition. In this technique, the acceptance angle of the system is radiometrically matched to the angular spread of the site's average irradiance conditions using a simple geometric ratio. The optical efficiency of CPV systems from flat-plate to high-concentration is plotted at all irradiance conditions. Concentrator systems are measured outdoors in various irradiance conditions to test the methodology. This modeling technique is valuable at the design stage to determine the ideal level of concentration for a CPV module. It requires only two inputs: the acceptance angle profile of the system and the site's average direct and diffuse irradiance fractions. Acceptance angle can be determined by raytracing or testing a fabricated prototype in the lab with a solar simulator. The average irradiance conditions can be found in the Typical Metrological Year (TMY3) database. Additionally, the information gained from this technique can be used to determine tracking tolerance, quantify power loss during an isolated weather event, and do more sophisticated analysis such as I-V curve simulation.

  20. On-ground characterization of Rosetta/VIRTIS-M. II. Spatial and radiometric calibrations

    SciTech Connect

    Filacchione, G.; Ammannito, E.; Coradini, A.; Capaccioni, F.; Piccioni, G.; De Sanctis, M. C.; Dami, M.; Barbis, A.

    2006-10-15

    After having considered the spectral and geometrical performances of the Rosetta/VIRTIS-M experiment, we complete here the analysis by evaluating quantitatively the flat-field and radiometric responses. The purpose of this work is to retrieve the flat-field matrix necessary to homogenize the focal plane response. Moreover, the most important result is the determination of the instrument transfer function that allows to convert digital numbers in physical units of spectral radiance (W m{sup -2} {mu}m{sup -1} sterad{sup -1}). The strategy adopted to organize measurement sequence, a basic description of the on-ground experimental setups and the analysis of the collected data, is included in this article. An analysis of the instrumental stability has been performed as well by examining how the internal calibration data are affected by environmental conditions. These data allow to evaluate the cumulative effects of thermal and vibrational stresses on the instrumental performances: up to now we have verified that this effect is negligible. Finally the basic calibration pipeline used to calibrate in-flight data with on-ground parameters is fully described.

  1. Planned radiometrically calibrated and geometrically corrected products of lunar high-resolution Terrain Camera on SELENE

    NASA Astrophysics Data System (ADS)

    Haruyama, J.; Ohtake, M.; Matsunaga, T.; Morota, T.; Yokota, Y.; Honda, C.; Hirata, N.; Demura, H.; Iwasaki, A.; Nakamura, R.; Kodama, S.; LISM Working Group

    2008-07-01

    Surface relief maps have a significant role in the investigation of the solid planets. A 10 m resolution stereoscopic push-broom imager called the Terrain Camera (TC) will be installed on the Selenological and Engineering Explorer (SELENE), a Japanese lunar polar orbiter to be launched in 2007, to acquire lunar global topographic data from which lunar relief maps will be produced. Appropriate radiometric calibration and geometric correction (RGC) processing is required to construct reliable surface maps. An RGC processing system has already been installed in the SELENE Operation and Analysis Center (SOAC) of the Japanese Aerospace Exploration Agency (JAXA). The main tasks of the RGC processing system for TC data are dark-level correction, flat-field correction, photometric calibration, conversion of radiance to reflectance, and map projection. The several TC RGC-processed products in a scene size are superimposed, mosaicked, and stored in the SELENE level-2 database (L2DB) system as a relief map product. Relief maps of the entire Moon are scheduled for completion 1 year after the end of the SELENE nominal mission. Since a global 10 m resolution lunar relief map has never been produced before, the maps from the TC data will be valuable for lunar sciences and future exploration.

  2. Vegetation canopy optical and structural variability based on radiometric and laser analysis

    NASA Astrophysics Data System (ADS)

    Dim, Jules R.; Kajiwara, Koji; Honda, Yoshiaki

    2007-10-01

    For a comprehensive vegetation monitoring and/or management, a good understanding of the distribution of the solar radiation energy among components of this vegetation is needed. The energy received by the vegetation is measured by spectroradiometers either at satellite elevations or near the ground (in situ measurements). In this study, in situ, radiometric data and laser scanning techniques are combined, in order to evaluate the contribution of the vegetation structure to the variability of canopy reflectance. Advanced processing laser techniques are not only an efficient tool for the generation of physical models but also give information about the vertical structure of canopies (height, shape, density) and their horizontal extension. To conduct this study, airborne multispectral radiation data and, laser pulse returns are recorded from a low flying helicopter above the vegetation of a boreal forest. These measurements are used to derive canopy optical and structural variables. The impact of the canopy 2-dimensional structural variability on the distribution of the solar radiation reflected by plants of this area is discussed. The results obtained show that the laser technology can be used for the selection of the most appropriate configuration of radiation measurements, and optimization of canopy physical characteristics, in future airborne missions.

  3. Radiometric analysis of samples of domestic fish species and radiological implications.

    PubMed

    Tahir, S N A; Alaamer, A S; Ayub, M; Khan, M Z

    2010-05-01

    Radiometric analysis of samples of commonly sold fish species in Pakistan were carried out for the measurement of concentrations of naturally occurring and artificial radionuclides. For this purpose, a high resolution Ge detector was employed. Mean concentrations of (226)Ra, (228)Ra, and (40)K in fish samples were 1.3 +/- 0.3, 1.0 +/- 0.2, and 90 +/- 15 Bq kg, respectively, whereas concentration of (137)Cs was not detected. The annual effective dose due to ingestion of these radionuclides through fish diet was evaluated to be 2.3 microSv y(-1). This value of effective dose is found much below the average radiation dose of 0.29 mSv y(-1) received per capita worldwide through ingestion of natural radionuclides during the consumption of food assessed by the United Nations Scientific Committee on the Effects of Atomic Radiation. It is concluded that fish supplies in the markets from the domestic fish farms are free from radiological risks. These results may contribute to the national and regional data regarding radioactivity levels in domestic fish species. PMID:20386204

  4. Radiometric Cross-calibration of KOMPSAT-3A with Landsat-8

    NASA Astrophysics Data System (ADS)

    Shin, D. Y.; Ahn, H. Y.; Lee, S. G.; Choi, C. U.; Kim, J. S.

    2016-06-01

    In this study, Cross calibration was conducted at the Libya 4 PICS site on 2015 using Landsat-8 and KOMPSAT-3A. Ideally a cross calibration should be calculated for each individual scene pair because on any given date the TOA spectral profile is influenced by sun and satellite view geometry and the atmospheric conditions. However, using the near-simultaneous images minimizes this effect because the sensors are viewing the same atmosphere. For the cross calibration, the calibration coefficient was calculated by comparing the at sensor spectral radiance for the same location calculated using the Landsat-8 calibration parameters in metadata and the DN of KOMPSAT-3A for the regions of interest (ROI). Cross calibration can be conducted because the satellite sensors used for overpass have a similar bandwidth. However, not all satellites have the same color filter transmittance and sensor reactivity, even though the purpose is to observe the visible bands. Therefore, the differences in the RSR should be corrected. For the cross-calibration, a calibration coefficient was calculated using the TOA radiance and KOMPSAT-3 DN of the Landsat-8 OLI overpassed at the Libya 4 Site, As a result, the accuracy of the calibration coefficient at the site was assumed to be ± 1.0%. In terms of the results, the radiometric calibration coefficients suggested here are thought to be useful for maintaining the optical quality of the KOMPSAT-3A.

  5. Characterization of the Sonoran desert as a radiometric calibration target for Earth observing sensors

    USGS Publications Warehouse

    Angal, Amit; Chander, Gyanesh; Xiong, Xiaoxiong; Choi, Tae-young; Wu, Aisheng

    2011-01-01

    To provide highly accurate quantitative measurements of the Earth's surface, a comprehensive calibration and validation of the satellite sensors is required. The NASA Moderate Resolution Imaging Spectroradiometer (MODIS) Characterization Support Team, in collaboration with United States Geological Survey, Earth Resources Observation and Science Center, has previously demonstrated the use of African desert sites to monitor the long-term calibration stability of Terra MODIS and Landsat 7 (L7) Enhanced Thematic Mapper plus (ETM+). The current study focuses on evaluating the suitability of the Sonoran Desert test site for post-launch long-term radiometric calibration as well as cross-calibration purposes. Due to the lack of historical and on-going in situ ground measurements, the Sonoran Desert is not usually used for absolute calibration. An in-depth evaluation (spatial, temporal, and spectral stability) of this site using well calibrated L7 ETM+ measurements and local climatology data has been performed. The Sonoran Desert site produced spatial variability of about 3 to 5% in the reflective solar regions, and the temporal variations of the site after correction for view-geometry impacts were generally around 3%. The results demonstrate that, barring the impacts due to occasional precipitation, the Sonoran Desert site can be effectively used for cross-calibration and long-term stability monitoring of satellite sensors, thus, providing a good test site in the western hemisphere.

  6. Application of gamma-ray spectrometry in a NORM industry for its radiometrical characterization

    NASA Astrophysics Data System (ADS)

    Mantero, J.; Gázquez, M. J.; Hurtado, S.; Bolívar, J. P.; García-Tenorio, R.

    2015-11-01

    Industrial activities involving Naturally Occurring Radioactive Materials (NORM) are found among the most important industrial sectors worldwide as oil/gas facilities, metal production, phosphate Industry, zircon treatment, etc. being really significant the radioactive characterization of the materials involved in their production processes in order to assess the potential radiological risk for workers or natural environment. High resolution gamma spectrometry is a versatile non-destructive radiometric technique that makes simultaneous determination of several radionuclides possible with little sample preparation. However NORM samples cover a wide variety of densities and composition, as opposed to the standards used in gamma efficiency calibration, which are either water-based solutions or standard/reference sources of similar composition. For that reason self-absorption correction effects (especially in the low energy range) must be considered individually in every sample. In this work an experimental and a semi-empirical methodology of self-absorption correction were applied to NORM samples, and the obtained results compared critically, in order to establish the best practice in relation to the circumstances of an individual laboratory. This methodology was applied in samples coming from a TiO2 factory (NORM industry) located in the south-west of Spain where activity concentration of several radionuclides from the Uranium and Thorium series through the production process was measured. These results will be shown in this work.

  7. The absolute radiometric calibration of the advanced very high resolution radiometer

    NASA Technical Reports Server (NTRS)

    Slater, P. N.; Teillet, P. M.; Mao, Y.

    1987-01-01

    The early results of an absolute radiometric calibration of the NOAA-9 AVHRR sensor indicate significant degradations in the response of bands 1 and 2 compared to prelaunch values. The results are currently in the process of being verified and it may be that refinements of the methodology will be in order as additional data sets are analyzed. The LANDSAT TM calibration used in this approach is known to be very precise and the Herman radiative transfer code, supplemented by the 5-S code for gaseous transmission, is reliable as well. The extent to which other steps in the analysis procedure give rise to uncertainties in the results is currently under investigation. Particular attention is being given to the geometric matching of the AVHRR and TM imagery, as well as to the spectral redistribution procedure. By taking advantage of a reasonably precise calibration of TM imagery acquired on the same day as the AVHRR data at White Sands, a promising approach to the in-orbit calibration of AVHRR sensors is being developed. Current efforts involve primarily the examination of additional test cases and the investigation of possible simplifications in the procedure through judicious use of atmospheric models.

  8. Radiometric calibration and stability of the Landsat-8 Operational Land Imager (OLI)

    NASA Astrophysics Data System (ADS)

    Markham, Brian L.; Barsi, Julia A.; Kaita, Edward; Ong, Lawrence; Morfitt, Ron A.; Haque, Md. O.

    2015-09-01

    Landsat-8 and its two Earth imaging sensors, the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) have been operating on-orbit for 2 1/2 years. The OLI radiometric calibration, which is monitored using on-board lamps, on-board solar diffusers, the moon and vicarious calibration techniques has been stable to within 1% over this period of time. The Coastal Aerosol band, band 1, shows the largest change at about 1% over the period; all other bands have shown no significant trend. OLI bands 1- 4 show small discontinuities in response (+0.1% to 0.2%) beginning about 7 months after launch and continuing for about 1 month associated with a power cycling of the instrument, though the origin of the recovery is unclear. To date these small changes have not been compensated for, but this will change with a reprocessing campaign that is currently scheduled for Fall 2015. The calibration parameter files (each typically covering a 3 month period) will be updated for these observed gain changes. A fitted response to an adjusted average of the lamps, solar and lunar results will represent the trend, sampled at the rate of one value per CPF.

  9. Remote sensing of row crop structure and component temperatures using directional radiometric temperatures and inversion techniques

    NASA Technical Reports Server (NTRS)

    Kimes, D. S.

    1983-01-01

    A physically based sensor response model of a row crop was used as the mathematical framework from which several inversion strategies were tested for extracting row structure information and component temperatures using a series of sensor view angles. The technique was evaluated on ground-based radiometric thermal infrared data of a cotton row crop that covered 48 percent of the ground in the vertical projection. The results showed that the accuracies of the predicted row heights and widths, vegetation temperatures, and soil temperatures of the cotton row crop were on the order of 5 cm, 1 deg, and 2 deg C, respectively. The inversion techniques can be applied to directional sensor data from aircraft platforms and even space platforms if the effects of atmospheric absorption and emission can be corrected. In theory, such inversion techniques can be applied to a wide variety of vegetation types and thus can have significant implications for remote sensing research and applications in disciplines that deal with incomplete vegetation canopies.

  10. Correlations between altimetric sea surface height and radiometric sea surface temperature in the South Atlantic

    NASA Astrophysics Data System (ADS)

    Jones, Matthew S.; Allen, Myles; Guymer, Trevor; Saunders, Mark

    1998-04-01

    In the last decade, satellite altimetric measurements of sea surface height (SSH) and infrared radiometric measurements of sea surface temperature (SST) have provided a wealth of information about ocean circulation and atmosphere-ocean interactions. SSH is a depth-integrated quantity dependent upon the temperature and salinity structure of the water column and on the depth independent barotropic contribution. SST from infrared radiometers is a surface parameter representing the temperature of the top few microns of the ocean surface. Hence any relationship between SST and SSH provides dynamical information about the coupling between the ocean surface and subsurface. It also offers a promise of new techniques such as interpolating SSH data using SST and of improved calculations of eddy kinetic energy. We use SST data from the along-track scanning radiometer on ERS-I and SSH data from the TOPEX/POSEIDON instrument to examine the relationship between SST and SSH anomalies within the South Atlantic region for 1993 and 1994. We find that positive (≈0.2-0.6) spatial cross correlations between SST and SSH anomalies at zero lag are present throughout the region at large scales (wavelengths >1000 km). Small-scale correlations, however, are high (≈0.7) only in areas associated with fronts and mesoscale variability. These small-scale correlations are seasonal, being strongest in winter and weakest in summer. We discuss the application of these correlations to various techniques requiring the synergistic use of SSH and SST data.

  11. Using AIRS and IASI Data to Evaluate Absolute Radiometric Accuracy and Stability for Climate Applications

    NASA Technical Reports Server (NTRS)

    Aumann, Hartmut H.; Pagano, Thomas S.

    2008-01-01

    The creation of multi-decadal data sets for climate research requires better than 100 mK absolute calibration accuracy for the full range of spectral temperatures encountered under global conditions. Validation that this accuracy is achieved by the operational hyperspectral sounders from polar orbit is facilitated by comparing data from two instruments. Extreme radiometric calibration stability is critical to allow a long time series of noisy, but presumably long-term accurate truth measurements to be used for the validation of absolute accuracy at the 100 mK level. We use the RTGSST in the tropical oceans as ground truth. The difference between the AIRS derived sst2616 and the RTGSST based on six years of data shows a systematic cold bias of about 250 mK, but better than 4 mK/year stability. The double difference between AIRS and the RTGSST and IASI and the RTGSST with less than one year of data already allows statements at the 100 mK absolute level. It shows a 60 mK difference between the AIRS and the IASI calibration at 2616 cm-(sup 1) and 300 K, with a statistically insignificant 20 mK shift in six months.

  12. Radiometric calibration of the in-flight blackbody calibration system of the GLORIA interferometer

    NASA Astrophysics Data System (ADS)

    Monte, C.; Gutschwager, B.; Adibekyan, A.; Kehrt, M.; Ebersoldt, A.; Olschewski, F.; Hollandt, J.

    2014-01-01

    GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) is an airborne, imaging, infrared Fourier transform spectrometer that applies the limb-imaging technique to perform trace gas and temperature measurements in the Earth's atmosphere with three-dimensional resolution. To ensure the traceability of these measurements to the International Temperature Scale and thereby to an absolute radiance scale, GLORIA carries an on-board calibration system. Basically, it consists of two identical large-area and high-emissivity infrared radiators, which can be continuously and independently operated at two adjustable temperatures in a range from -50 °C to 0 °C during flight. Here we describe the radiometric and thermometric characterization and calibration of the in-flight calibration system at the Reduced Background Calibration Facility of the Physikalisch-Technische Bundesanstalt. This was performed with a standard uncertainty of less than 110 mK. Extensive investigations of the system concerning its absolute radiation temperature and spectral radiance, its temperature homogeneity and its short- and long-term stability are discussed. The traceability chain of these measurements is presented.

  13. The absolute radiometric calibration of the advanced very high resolution radiometer

    NASA Technical Reports Server (NTRS)

    Slater, P. N.; Teillet, P. M.; Ding, Y.

    1988-01-01

    An increasing number of remote sensing investigations require radiometrically calibrated imagery from NOAA Advanced Very High Resolution Radiation (AVHRR) sensors. Although a prelaunch calibration is done for these sensors, there is no capability for monitoring any changes in the in-flight absolute calibration for the visible and near infrared spectral channels. Hence, the possibility of using the reflectance-based method developed at White Sands for in-orbit calibration of LANDSAT Thematic Mapper (TM) and SPOT Haute Resolution Visible (HVR) data to calibrate the AVHRR sensor was investigated. Three diffrent approaches were considered: Method 1 - ground and atmospheric measurements and reference to another calibrated satellite sensor; Method 2 - ground and atmospheric measurements with no reference to another sensor; and Method 3 - no ground and atmospheric measurements but reference to another satellite sensor. The purpose is to describe an investigation on the use of Method 2 to calibrate NOAA-9 AVHRR channels 1 and 2 with the help of ground and atmospheric measurements at Rogers (dry) Lake, Edwards Air Force Base (EAFB) in the Mojave desert of California.

  14. Radiometric calibration stability of the EO-1 advanced land imager: 5 years on-orbit

    USGS Publications Warehouse

    Markham, B.L.; Ong, L.; Barsi, J.A.; Mendenhall, J.A.; Lencioni, D.E.; Helder, D.L.; Hollaren, D.M.; Morfitt, R.

    2006-01-01

    The Advanced Land Imager (ALI) was developed as a prototype sensor for follow on missions to Landsat-7. It was launched in November 2000 on the Earth Observing One (EO-1) satellite as a nominal one-year technology demonstration mission. As of this writing, the sensor has continued to operate in excess of 5 years. Six of the ALl's nine multi-spectral (MS) bands and the panchromatic band have similar spectral coverage as those on the Landsat-7 ETM+. In addition to on-board lamps, which have been significantly more stable than the lamps on ETM+, the ALI has a solar diffuser and has imaged the moon monthly since launch. This combined calibration dataset allows understanding of the radiometric stability of the ALI system, its calibrators and some differentiation of the sources of the changes with time. The solar dataset is limited as the mechanism controlling the aperture to the solar diffuser failed approximately 18 months after launch. Results over 5 years indicate that: the shortest wavelength band (443 nm) has degraded in response about 2%; the 482 nm and 565 nm bands decreased in response about 1%; the 660 nm, 790 nm and 868 nm bands each degraded about 5%; the 1250 nm and 1650 nm bands did not change significantly and the 2215 nm band increased in response about 2%.

  15. On-orbit radiometric calibration over time and between spacecraft using the moon

    USGS Publications Warehouse

    Kieffer, H.H.; Stone, T.C.; Barnes, R.A.; Bender, S.; Eplee, R.E., Jr.; Mendenhall, J.; Ong, L.

    2002-01-01

    The Robotic Lunar Observatory (ROLO) project has developed a spectral irradiance model of the Moon that accounts for variations with lunar phase through the bright half of a month, lunar librations, and the location of an Earth-orbiting spacecraft. The methodology of comparing spacecraft observations of the Moon with this model has been developed to a set of standardized procedures so that comparisons can be readily made. In the cases where observations extend over several years (e.g., SeaWiFS), instrument response degradation has been determined with precision of about 0.1% per year. Because of the strong dependence of lunar irradiance on geometric angles, observations by two spacecraft cannot be directly compared unless acquired at the same time and location. Rather, the lunar irradiance based on each spacecraft instrument calibration can be compared with the lunar irradiance model. Even single observations by an instrument allow inter-comparison of its radiometric scale with other instruments participating in the lunar calibration program. Observations by SeaWiFS, ALI, Hyperion and MTI are compared here.

  16. Improved detection of tides at Europa with radiometric and optical tracking during flybys

    NASA Astrophysics Data System (ADS)

    Park, Ryan S.; Bills, Bruce; Buffington, Brent B.; Folkner, William M.; Konopliv, Alexander S.; Martin-Mur, Tomas J.; Mastrodemos, Nickolaos; McElrath, Timothy P.; Riedel, Joseph E.; Watkins, Michael M.

    2015-07-01

    Due to its eccentric orbit about Jupiter, Europa experiences periodic tidal deformation, which causes changes in its gravitational field and induces both radial and transverse displacements of the surface. The amplitude and phase of these tidal changes are diagnostic of internal structure, and can be measured with sufficient radiometric and optical tracking of a spacecraft during a series of flyby encounters with Europa. This paper presents results of the simulated accuracy for recovery of the tides of Europa through measuring the second-degree tidal Love numbers k2, h2, and l2. A reference trajectory, which consists of a total of 45 close flybys, was considered and a detailed covariance analysis was performed. The study was based on Earth-based Doppler tracking during ± 2 h of each periapsis passage and surface imaging data taken below 500 km altitude. The result shows that the formal uncertainty of the second-degree tidal Love numbers can be estimated to be σk2 = 0.01 , σh2 = 0.02 , and σl2 = 0.01 , which is sufficient to constrain the global ice thickness to about 10 km under reasonable assumptions. Moreover, the forced librations of Europa can be measured to 0.3″ accuracy, which can further constrain Europa's interior structure.

  17. Estimation of the cloud transmittance from radiometric measurements at the ground level

    SciTech Connect

    Costa, Dario; Mares, Oana

    2014-11-24

    The extinction of solar radiation due to the clouds is more significant than due to any other atmospheric constituent, but it is always difficult to be modeled because of the random distribution of clouds on the sky. Moreover, the transmittance of a layer of clouds is in a very complex relation with their type and depth. A method for estimating cloud transmittance was proposed in Paulescu et al. (Energ. Convers. Manage, 75 690–697, 2014). The approach is based on the hypothesis that the structure of the cloud covering the sun at a time moment does not change significantly in a short time interval (several minutes). Thus, the cloud transmittance can be calculated as the estimated coefficient of a simple linear regression for the computed versus measured solar irradiance in a time interval Δt. The aim of this paper is to optimize the length of the time interval Δt. Radiometric data measured on the Solar Platform of the West University of Timisoara during 2010 at a frequency of 1/15 seconds are used in this study.

  18. Dynamic tool to estimate the measurement error in radiometric IR cameras

    NASA Astrophysics Data System (ADS)

    Schoenbach, Bernd

    2001-03-01

    In various applications of Infrared (IR) Thermography there is need for measuring true surface temperatures. Modern radiometric IR cameras are equipped with sophisticated tools like internal temperature sensors or internal temperature references to provide stabilized temperature read-outs and can guarantee a specified accuracy. But these manufacturer's accuracy specifications are only valid for known objects and under controlled laboratory conditions. In field use there are external effects such as unknown object emissivity, reflections or absorption that can be compensated by means of mathematical models. These factors usually have a significant influence on the results thus making it difficult for the user to estimate the real accuracy of the measurement. This paper introduces a computer tool where the thermographic measurement situation has been implemented in an MS Excel spreadsheet file. The user can vary the measurement parameters in the spreadsheet very easily using graphic controls called sliders. In a mixed numeric and graphical presentation the user can get a feel for the influence of a certain parameter in a specific situation and the model provides a good estimate of the measurement accuracy under realistic conditions.

  19. Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band

    SciTech Connect

    Flittner, D.E.; Herman, B.M.; Thome, K.J.; Simpson, J.M.; Reagan, J.A. )

    1993-04-15

    A second-derivative smoothing technique, commonly used in inversion work, is applied to the problem of inferring total columnar ozone amounts and aerosol optical depths. The application is unique in that the unknowns (i.e., total columnar ozone and aerosol optical depth) may be solved for directly without employing standard inversion methods. It is shown, however, that by employing inversion constraints, better solutions are normally obtained. The current method requires radiometric measurements of total optical depth through the Chappuis ozone band. It assumes no a priori shape for the aerosol optical depth versus wavelength profile and makes no assumptions about the ozone amount. Thus, the method is quite versatile and able to deal with varying total ozone and various aerosol size distributions. The technique is applied first in simulation, then to 119 days of measurements taken in Tucson, Arizona, that are compared to TOMS values for the same dates. The technique is also applied to two measurements taken at Mauna Loa, Hawaii, for which Dobson ozone values are available in addition to the TOMS values, and the results agree to within 15%. It is also shown through simulations that additional information can be obtained from measurements outside the Chappuis band. This approach reduces the bias and spread of the estimates total ozone and is unique in that it uses measurements from both the Chappuis and Huggins absorption bands. 12 refs., 6 figs., 2 tabs.

  20. In-flight radiometric calibration of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

    NASA Technical Reports Server (NTRS)

    Conel, James E.; Green, Robert O.; Alley, Ronald E.; Bruegge, Carol J.; Carrere, Veronique; Margolis, Jack S.; Vane, Gregg; Chrien, Thomas G.; Slater, Philip N.; Biggard, Stuart F.

    1988-01-01

    A reflectance-based method was used to provide an analysis of the in-flight radiometric performance of AVIRIS. Field spectral reflectance measurements of the surface and extinction measurements of the atmosphere using solar radiation were used as input to atmospheric radiative transfer calculations. Five separate codes were used in the analysis. Four include multiple scattering, and the computed radiances from these for flight conditions were in good agreement. Code-generated radiances were compared with AVIRIS-predicted radiances based on two laboratory calibrations (pre- and post-season of flight) for a uniform highly reflecting natural dry lake target. For one spectrometer (C), the pre- and post-season calibration factors were found to give identical results, and to be in agreement with the atmospheric models that include multiple scattering. This positive result validates the field and laboratory calibration technique. Results for the other spectrometers (A, B and D) were widely at variance with the models no matter which calibration factors were used. Potential causes of these discrepancies are discussed.

  1. Bolometric kinetic inductance detector technology for sub-millimeter radiometric imaging

    NASA Astrophysics Data System (ADS)

    Hassel, Juha; Timofeev, Andrey V.; Vesterinen, Visa; Sipola, Hannu; Helistö, Panu; Aikio, Mika; Mäyrä, Aki; Grönberg, Leif; Luukanen, Arttu

    2015-10-01

    Radiometric sub-millimeter imaging is a candidate technology especially in security screening applications utilizing the property of radiation in the band of 0.2 - 1.0 THz to penetrate through dielectric substances such as clothing. The challenge of the passive technology is the fact that the irradiance corresponding to the blackbody radiation is very weak in this spectral band: about two orders of magnitude below that of the infrared band. Therefore the role of the detector technology is of ultimate importance to achieve sufficient sensitivity. In this paper we present results related to our technology relying on superconducting kinetic inductance detectors operating in a thermal (bolometric) mode. The detector technology is motivated by the fact that it is naturally suitable for scalable multiplexed readout systems, and operates with relatively simple cryogenics. We will review the basic concepts of the detectors, and provide experimental figures of merit. Furthermore, we will discuss the issues related to the scale-up of our detector technology into large 2D focal plane arrays.

  2. A Maximum Likelihood Approach to Determine Sensor Radiometric Response Coefficients for NPP VIIRS Reflective Solar Bands

    NASA Technical Reports Server (NTRS)

    Lei, Ning; Chiang, Kwo-Fu; Oudrari, Hassan; Xiong, Xiaoxiong

    2011-01-01

    Optical sensors aboard Earth orbiting satellites such as the next generation Visible/Infrared Imager/Radiometer Suite (VIIRS) assume that the sensors radiometric response in the Reflective Solar Bands (RSB) is described by a quadratic polynomial, in relating the aperture spectral radiance to the sensor Digital Number (DN) readout. For VIIRS Flight Unit 1, the coefficients are to be determined before launch by an attenuation method, although the linear coefficient will be further determined on-orbit through observing the Solar Diffuser. In determining the quadratic polynomial coefficients by the attenuation method, a Maximum Likelihood approach is applied in carrying out the least-squares procedure. Crucial to the Maximum Likelihood least-squares procedure is the computation of the weight. The weight not only has a contribution from the noise of the sensor s digital count, with an important contribution from digitization error, but also is affected heavily by the mathematical expression used to predict the value of the dependent variable, because both the independent and the dependent variables contain random noise. In addition, model errors have a major impact on the uncertainties of the coefficients. The Maximum Likelihood approach demonstrates the inadequacy of the attenuation method model with a quadratic polynomial for the retrieved spectral radiance. We show that using the inadequate model dramatically increases the uncertainties of the coefficients. We compute the coefficient values and their uncertainties, considering both measurement and model errors.

  3. Radiometric immunosorbent assay for the detection of anti-hormone-binding protein antibodies

    SciTech Connect

    Pierce, E.A.; Dame, M.C.; DeLuca, H.F.

    1986-02-15

    A radiometric immunosorbent assay (RISA) for the detection of monoclonal antibodies to hormone-binding proteins has been developed. The assay involves incubating hybridoma supernatants in microtiter wells that have been coated with goat anti-mouse IgG antibodies. Any mouse IgG in the test supernatant is thus specifically retained in the wells. Radioactive ligand-binding protein complexes are then incubated in the wells. The presence of anti-binding protein antibodies in the supernatant is indicated by specific retention of radioactive ligand-binding protein complexes in the wells. Crude antigen preparations, such as tissue homogenates, can be used to detect antibodies. The assay is capable of detecting antibody at concentrations 20 ng/ml (approx. 100 pM IgG). The RISA has been used successfully to screen for monoclonal antibodies to the intracellular receptor for 1,25-dihydroxyvitamin D/sub 3/ and should be useful for the detection of antibodies to ligand-binding proteins in general.

  4. Recent results from the Radiometric Calibration Test Site (RadCaTS) at Railroad Valley, Nevada

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, Jeffrey S.; Leisso, Nathan P.

    2010-09-01

    The Radiometric Calibration Test Site (RadCaTS) is an automated approach to ground-based vicarious calibration that does not require on-site personnel during the overpass of an airborne or spaceborne sensor. The concept originates as an attempt to increase the amount of ground-based data that are collected throughout the year. All-weather instruments are used to measure atmospheric and surface conditions. The data are used in an automated processing scheme to produce top-of-atmosphere spectral radiance, which are then compared to the sensor under test. RadCaTS has been located at Railroad Valley, Nevada, since 2004, but the concept is applicable to any site that is suitable for vicarious calibration. Railroad Valley was chosen to test the RadCaTS concept because it has been used by the Remote Sensing Group (RSG) for over 15 years and is well understood. This work describes the RadCaTS automated concept, and outlines the automated processing scheme that is used to determine the surface reflectance. A description of the instrumentation used to measure the surface reflectance and atmosphere is presented, followed by a discussion of their placement on the site, and also their calibration. Finally, the RadCaTS ground-based results are compared to those from Aqua and Terra MODIS in 2008, and Landsat 7 ETM+ in 2009.

  5. High-throughput radiometric CYP2C19 inhibition assay using tritiated (S)-mephenytoin.

    PubMed

    Di Marco, Annalise; Cellucci, Antonella; Chaudhary, Ashok; Fonsi, Massimiliano; Laufer, Ralph

    2007-10-01

    A rapid and sensitive radiometric assay for assessing the potential of drugs to inhibit cytochrome P450 (P450) 2C19 in human liver microsomes is described. The new assay, which does not require high-performance liquid chromatography (HPLC) separation or mass spectrometric detection, is based on the release of tritium as tritiated water that occurs upon CYP2C19-mediated 4'-hydroxylation of (S)-mephenytoin labeled with tritium in the 4' position. Because this reaction is subject to an NIH shift, tritium was also introduced into the 3'- and 5'-positions of the tracer to enhance formation of a tritiated water product. Tritiated water was separated from the substrate using 96-well solid-phase extraction plates. The reaction is NADPH-dependent and sensitive to CYP2C19 inhibitors. IC(50) values for 15 diverse drugs differed less than 2.5-fold from those determined by quantification of the unlabeled 4'-hydroxy-(S)-mephenytoin product, using HPLC coupled to mass spectrometric detection. All of the steps of the new assay, namely incubation, product separation, and radioactivity counting, are performed in a 96-well format and can be automated. This assay represents a non-HPLC, high-throughput version of the classic (S)-mephenytoin 4'-hydroxylation assay, which is the most widely used method to assess the potential for CYP2C19 inhibition of new chemical entities. PMID:17600081

  6. Radiometric compensation for cooperative distributed multi-projection system through 2-DOF distributed control.

    PubMed

    Tsukamoto, Jun; Iwai, Daisuke; Kashima, Kenji

    2015-11-01

    This paper proposes a novel radiometric compensation technique for cooperative projection system based-on distributed optimization. To achieve high scalability and robustness, we assume cooperative projection environments such that 1. each projector does not have information about other projectors as well as target images, 2. the camera does not have information about the projectors either, while having the target images, and 3. only a broadcast communication from the camera to the projectors is allowed to suppress the data transfer bandwidth. To this end, we first investigate a distributed optimization based feedback mechanism that is suitable for the required decentralized information processing environment. Next, we show that this mechanism works well for still image projection, however not necessary for moving images due to the lack of dynamic responsiveness. To overcome this issue, we propose to implement an additional feedforward mechanism. Such a 2 Degree Of Freedom (2-DOF) control structure is well-known in control engineering community as a typical method to enhance not only disturbance rejection but also reference tracking capability, simultaneously. We theoretically guarantee and experimentally demonstrate that this 2-DOF structure yields the moving image projection accuracy that is overwhelming the best achievable performance only by the distributed optimization mechanisms. PMID:26439824

  7. Image processing software for providing radiometric inputs to land surface climatology models

    NASA Technical Reports Server (NTRS)

    Newcomer, Jeffrey A.; Goetz, Scott J.; Strebel, Donald E.; Hall, Forrest G.

    1989-01-01

    During the First International Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), 80 gigabytes of image data were generated from a variety of satellite and airborne sensors in a multidisciplinary attempt to study energy and mass exchange between the land surface and the atmosphere. To make these data readily available to researchers with a range of image data handling experience and capabilities, unique image-processing software was designed to perform a variety of nonstandard image-processing manipulations and to derive a set of standard-format image products. The nonconventional features of the software include: (1) adding new layers of geographic coordinates, and solar and viewing conditions to existing data; (2) providing image polygon extraction and calibration of data to at-sensor radiances; and, (3) generating standard-format derived image products that can be easily incorporated into radiometric or climatology models. The derived image products consist of easily handled ASCII descriptor files, byte image data files, and additional per-pixel integer data files (e.g., geographic coordinates, and sun and viewing conditions). Details of the solutions to the image-processing problems, the conventions adopted for handling a variety of satellite and aircraft image data, and the applicability of the output products to quantitative modeling are presented. They should be of general interest to future experiment and data-handling design considerations.

  8. Radiometric analysis of raw materials and end products in the Turkish ceramics industry

    NASA Astrophysics Data System (ADS)

    Turhan, Ş.; Arıkan, İ. H.; Demirel, H.; Güngör, N.

    2011-05-01

    This study presents the findings of radiometric analysis carried out to determine the activity concentrations of natural radionuclides in raw materials (clay, kaolin, quartz, feldspar, dolomite, alumina, bauxite, zirconium minerals, red mud and frit) and end products (glazed ceramic wall and floor tiles) in the Turkish ceramics industry. Hundred forty-six samples were obtained from various manufacturers and suppliers throughout the country and analyzed using gamma-ray spectrometer with HPGe detectors. Radiological parameters such as radium equivalent activity, activity concentration index and alpha index were calculated to assess the radiological aspects of the use of the ceramic end products as decorative or covering materials in construction sector. Results obtained were examined in the light of the relevant national and international legislation and guidance and compared with the results of similar studies reported in different countries. The results suggest that the use of ceramic end product samples examined in the construction of dwellings, workplaces and industrial buildings in Turkey is unlikely to give rise to any significant radiation exposure to the occupants.

  9. NERO: General concept of a Near-Earth object Radiometric Observatory

    NASA Astrophysics Data System (ADS)

    Cellino, A.; Somma, R.; Tommasi, L.; Paolinetti, R.; Muinonen, K.; Virtanen, J.; Tedesco, E. F.; Delbò, M.

    Near-Earth objects Radiometric Observatory (NERO) is one of the six studies for possible missions dedicated to near-Earth objects, that were funded by the European Space Agency (ESA) in 2002 2003. It is a further development of some previous studies already submitted to ESA (Sysiphos, Spaceguard-1). The general concept is that a small satellite equipped with both a detector for visible wavelengths and an array for thermal IR measurements around 10 μm would be an ideal platform to obtain simultaneously two of the major objectives of current NEO science, namely the physical characterization of the objects and the discovery of those NEOs that are difficult to detect from the ground because their orbits are entirely or partly inside the Earth’s orbit. The NERO study includes a comprehensive analysis of the advantages and drawbacks of different orbital options for the satellite (including L2 of Earth and L2 of Venus) and a preliminary simulation of the effectiveness of orbit determination based on NERO observations of newly detected objects. The main results of this study, including also a preliminary sketch of the payload design (optics, detectors, cooling system, etc.) are briefly summarized.

  10. Performance and Results from a Space Borne, Uncooled Microbolometer Array Spectral Radiometric Imager

    NASA Technical Reports Server (NTRS)

    Spinhirne, James M; Scott, V. Stan; Lancaster, Redgie S.; Manizade, Kathrine; Palm, Steven P.

    2000-01-01

    The Infrared Spectral Imaging Radiometer experiment was flown on a space shuttle mission as a shuttle hitchhiker experiment in August of 1997. The goals of the experiment were to test uncooled array detectors for infrared spectral imaging from space and to apply for the first time retrieval from space of brightness temperatures of cloud, land and sea along with direct laser measurements of cloud top height. The instrument operates in 3 narrow and one broad spectral band, all between 7 and 13 microns in either stare or time-delay and integration mode. The nominal spatial resolution was 1/4 kilometer. Using onboard calibrations along with periodic views of deep space, radiometric calibration of imagery was carried out and performance analyzed. The noise equivalent temperature difference and absolute accuracy reported here varied with operating mode, spectral band and scene temperature but were within requirements. This paper provides a description of the instrument, its operating modes, the method of brightness temperature retrieval, the method of spectral registration and results from the flight.

  11. Radiometric and geometric analysis of hyperspectral imagery acquired from an unmanned aerial vehicle

    DOE PAGESBeta

    Hruska, Ryan; Mitchell, Jessica; Anderson, Matthew; Glenn, Nancy F.

    2012-09-17

    During the summer of 2010, an Unmanned Aerial Vehicle (UAV) hyperspectral in-flight calibration and characterization experiment of the Resonon PIKA II imaging spectrometer was conducted at the U.S. Department of Energy’s Idaho National Laboratory (INL) UAV Research Park. The purpose of the experiment was to validate the radiometric calibration of the spectrometer and determine the georegistration accuracy achievable from the on-board global positioning system (GPS) and inertial navigation sensors (INS) under operational conditions. In order for low-cost hyperspectral systems to compete with larger systems flown on manned aircraft, they must be able to collect data suitable for quantitative scientific analysis.more » The results of the in-flight calibration experiment indicate an absolute average agreement of 96.3%, 93.7% and 85.7% for calibration tarps of 56%, 24%, and 2.5% reflectivity, respectively. The achieved planimetric accuracy was 4.6 meters (based on RMSE).« less

  12. A simple and effective radiometric correction method to improve landscape change detection across sensors and across time

    USGS Publications Warehouse

    Chen, X.; Vierling, Lee; Deering, D.

    2005-01-01

    Satellite data offer unrivaled utility in monitoring and quantifying large scale land cover change over time. Radiometric consistency among collocated multi-temporal imagery is difficult to maintain, however, due to variations in sensor characteristics, atmospheric conditions, solar angle, and sensor view angle that can obscure surface change detection. To detect accurate landscape change using multi-temporal images, we developed a variation of the pseudoinvariant feature (PIF) normalization scheme: the temporally invariant cluster (TIC) method. Image data were acquired on June 9, 1990 (Landsat 4), June 20, 2000 (Landsat 7), and August 26, 2001 (Landsat 7) to analyze boreal forests near the Siberian city of Krasnoyarsk using the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and reduced simple ratio (RSR). The temporally invariant cluster (TIC) centers were identified via a point density map of collocated pixel VIs from the base image and the target image, and a normalization regression line was created to intersect all TIC centers. Target image VI values were then recalculated using the regression function so that these two images could be compared using the resulting common radiometric scale. We found that EVI was very indicative of vegetation structure because of its sensitivity to shadowing effects and could thus be used to separate conifer forests from deciduous forests and grass/crop lands. Conversely, because NDVI reduced the radiometric influence of shadow, it did not allow for distinctions among these vegetation types. After normalization, correlations of NDVI and EVI with forest leaf area index (LAI) field measurements combined for 2000 and 2001 were significantly improved; the r 2 values in these regressions rose from 0.49 to 0.69 and from 0.46 to 0.61, respectively. An EVI "cancellation effect" where EVI was positively related to understory greenness but negatively related to forest canopy coverage was evident across a

  13. Ground-based radiometric calibration of the Landsat 8 Operational Land Imager (OLI) using in situ techniques

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, J.

    2013-12-01

    Landsat 8 was successfully launched from Vandenberg Air Force Base in California on 11 February 2013, and was placed into the orbit previously occupied by Landsat 5. Landsat 8 is the latest platform in the 40-year history of the Landsat series of satellites, and it contains two instruments that operate in the solar-reflective and the thermal infrared regimes. The Operational Land Imager (OLI) is a pushbroom sensor that contains eight multispectral bands ranging from 400-2300 nm, and one panchromatic band. The spatial resolution of the multispectral bands is 30 m, which is similar to previous Landsat sensors, and the panchromatic band has a 15-m spatial resolution, which is also similar to previous Landsat sensors. The 12-bit radiometric resolution of OLI improves upon the 8-bit resolution of the Enhanced Thematic Mapper Plus (ETM+) onboard Landsat 7. An important requirement for the Landsat program is the long-term radiometric continuity of its sensors. Ground-based vicarious techniques have been used for over 20 years to determine the absolute radiometric calibration of sensors that encompass a wide variety of spectral and spatial characteristics. This work presents the early radiometric calibration results of Landsat 8 OLI that were obtained using the traditional reflectance-based approach. University of Arizona personnel used five sites in Arizona, California, and Nevada to collect ground-based data. In addition, a unique set of in situ data were collected in March 2013, when Landsat 7 and Landsat 8 were observing the same site within minutes of each other. The tandem overfly schedule occurred while Landsat 8 was shifting to the WRS-2 orbital grid, and lasted only a few days. The ground-based data also include results obtained using the University of Arizona's Radiometric Calibration Test Site (RadCaTS), which is an automated suite of instruments located at Railroad Valley, Nevada. The results presented in this work include a comparison to the L1T at

  14. Ten years of measured UV Index from the Spanish UVB Radiometric Network.

    PubMed

    Utrillas, M P; Marín, M J; Esteve, A R; Estellés, V; Gandía, S; Núnez, J A; Martínez-Lozano, J A

    2013-08-01

    An analysis is made of the UV Index (UVI) obtained from the ultraviolet erythemal solar radiation (UVER) data measured by the Spanish UVB Radiometric Network between the years 2000 and 2009. Previously, the daily UVI has been evaluated using two different criteria: (a) the value corresponding to solar noon; and (b) the daily maximum value. The mean percentage of agreement is 92% if we consider the cases for which the difference is zero or one UVI unit. These results are similar to those obtained in a previous work where only 2 years were analyzed. In all the stations the UVI reaches very high values (8-10) in spring-summer, and the very high and extreme (≥ 11) UVI values are more dependent on the continental effect than on the latitude effect. From the UVI values it is possible to classify the stations into four groups: Coastal stations, Continental stations (more than 200 km from the coast), Southern stations (Coastal stations but with similar values of UVI as the Continental ones due to their low latitude) and Canary Islands stations (1400 km southwest from the Iberian Peninsula thus lower latitude). The monthly mean maximum of UVI is reached in July due to the annual evolution of the total ozone column. This value corresponds, for a skin phototype II, to three times the minimal erythemal dose (MED) in an hour in a Coastal station, 3.5 MEDs in an hour measured in a Continental or Southern station and up five MEDs in an hour in the Izaña station (Canary Islands). The cumulative dose on a horizontal plane over an average year has been calculated for each station. More than 40% of the annual dose is received in summer, about 35% in spring, more than 11% in autumn and less than 10% in winter except for the stations in the Canary Islands where the difference between seasons is less significant. PMID:23685479

  15. Estimating land surface heat flux using radiometric surface temperature without the need for an extra resistance

    NASA Astrophysics Data System (ADS)

    Su, H.; Yang, Y.; Liu, S.

    2015-12-01

    Remotely-sensed land surface temperature (LST) is a key variable in energy balance and is widely used for estimating regional heat flux. However, the inequality between LST and aerodynamic surface temperature (Taero) poses a great challenge for regional heat flux estimation in one -source energy balance models. In this study, a one-source model for land (OSML) was proposed to estimate regional surface heat flux without a need for an empirical extra resistance. The proposed OSML employs both a conceptual VFC/LST trapezoid model and the electrical analogue formula of sensible heat flux (H) to estimate the radiometric-convective resistance (rae) by using a quartic equation. To evaluate the performance of OSML, the model was applied to the Soil Moisture-Atmosphere Coupling Experiment (SMACEX), using a remotely-sensed data set at a regional scale. Validated against tower observations, the root mean square deviation (RMSD) of H and latent heat flux (LE) from OSML was 47 W/m2 and 51 W/m2, which is comparable to other published studies. OSML and SEBS (Surface Energy Balance System) compared under the same available energy indicated that LE estimated by OSML is comparable to that derived from the SEBS model. In conducting further inter-comparisons of rae, the aerodynamic resistance derived from SEBS (ra_SEBS), and aerodynamic resistance (ra) derived from Brutsaert et al. (2005) in corn and soybean fields, we found that rae and ra_SEBS are comparable. Most importantly, our study indicates that the OSML method is applicable without having to acquire wind speed or to specify aerodynamic surface characteristics and that it is applicable to heterogeneous areas.

  16. Preliminary assessment of Suomi-NPP VIIRS on-orbit radiometric performance

    NASA Astrophysics Data System (ADS)

    Oudrari, Hassan; McIntire, Jeff; Moyer, David; Chiang, Kwofu; Xiong, Xiaoxiong; Butler, James

    2012-09-01

    The Visible-Infrared Imaging Radiometer Suite (VIIRS) is a key instrument on-board the Suomi National Polarorbiting Partnership (NPP) spacecraft that was launched on October 28th 2011. VIIRS was designed to provide moderate and imaging resolution of the planet Earth twice daily. It is a wide-swath (3,040 km) cross-track scanning radiometer with spatial resolutions of 375 m and 750 m at nadir for imaging and moderate bands, respectively. It has 22 spectral bands covering the spectrum between 0.4 μm and 12.5 μm, including 14 reflective solar bands (RSB), 7 thermal emissive bands (TEB), and 1 day-night band (DNB). VIIRS observations are used to generate 22 environmental data record (EDRs). This paper will briefly describe NPP VIIRS calibration strategies performed by the independent government team, for the initial on-orbit Intensive Calibration and Validation (ICV) activities. In addition, this paper will provide an early assessment of the sensor on-orbit radiometric performance, such as the sensor signal to noise ratios (SNRs), dual gain transition verification, dynamic range and linearity, reflective bands calibration based on the solar diffuser (SD) and solar diffuser stability monitor (SDSM), emissive bands calibration based on the on-board blackbody calibration (OBC), and cross-comparison with MODIS. A comprehensive set of performance metrics generated during the pre-launch testing program will be compared to VIIRS early on-orbit performance, and a plan for future cal/val activities and performance enhancements will be presented.

  17. 3D leaf water content mapping using terrestrial laser scanner backscatter intensity with radiometric correction

    NASA Astrophysics Data System (ADS)

    Zhu, Xi; Wang, Tiejun; Darvishzadeh, Roshanak; Skidmore, Andrew K.; Niemann, K. Olaf

    2015-12-01

    Leaf water content (LWC) plays an important role in agriculture and forestry management. It can be used to assess drought conditions and wildfire susceptibility. Terrestrial laser scanner (TLS) data have been widely used in forested environments for retrieving geometrically-based biophysical parameters. Recent studies have also shown the potential of using radiometric information (backscatter intensity) for estimating LWC. However, the usefulness of backscatter intensity data has been limited by leaf surface characteristics, and incidence angle effects. To explore the idea of using LiDAR intensity data to assess LWC we normalized (for both angular effects and leaf surface properties) shortwave infrared TLS data (1550 nm). A reflectance model describing both diffuse and specular reflectance was applied to remove strong specular backscatter intensity at a perpendicular angle. Leaves with different surface properties were collected from eight broadleaf plant species for modeling the relationship between LWC and backscatter intensity. Reference reflectors (Spectralon from Labsphere, Inc.) were used to build a look-up table to compensate for incidence angle effects. Results showed that before removing the specular influences, there was no significant correlation (R2 = 0.01, P > 0.05) between the backscatter intensity at a perpendicular angle and LWC. After the removal of the specular influences, a significant correlation emerged (R2 = 0.74, P < 0.05). The agreement between measured and TLS-derived LWC demonstrated a significant reduction of RMSE (root mean square error, from 0.008 to 0.003 g/cm2) after correcting for the incidence angle effect. We show that it is possible to use TLS to estimate LWC for selected broadleaved plants with an R2 of 0.76 (significance level α = 0.05) at leaf level. Further investigations of leaf surface and internal structure will likely result in improvements of 3D LWC mapping for studying physiology and ecology in vegetation.

  18. Study on method of radiometric calibration for precision measurement of micro size damage site

    NASA Astrophysics Data System (ADS)

    Yuan, Hao-yu; Peng, Zhi-tao; Wang, Wen-fang; Chen, Feng-dong; Tang, Jun; Feng, Bo; Liu, Guo-dong; Liu, Bing-guo

    2014-09-01

    Large aperture optical have high risk of damage when woke on high flux laser. For avoid lethal damages breakdown the expensive large aperture optical, replace the optical that damaged before damage site increase to can't repaired, we need precision measurement of optical surface damage sites size. The size of the optics which be detected is 400μm ×400μm, and the size of CCD array pixel is 4K×4K which we selected, so pixel resolution only 100μm of the Optical Damage Online Inspection system, it hard to measurement damage sites which size less than 100μm. This paper describes a method of radiometric calibration to measure online optical damage site that greater than 50μm by Optical Damage Online Inspection system. Numerical statement gray on CCD of different size damage sites by select a fixed variable of illumination intensity, shutter and numerical aperture of image-forming system. Fitting a curve with suitable function of gray and actual size, precision measure optical damage sites that greater than 50μm by the curve. Test results indicate that, the deviation less than 20% which measure size and actual size .This method settle problems of micro size damage site hard to measure online under the condition of long working distance and low optical resolution. At present, this method have used on Optical Damage Online Inspection system of high flux laser installation, it important significance for observation damage site size grown and accurately appraise the optical damage.

  19. Radiometric analysis of farmed fish (sea bass, gilthead bream, and rainbow trout) from Tenerife Island, Spain.

    PubMed

    Jalili, A; López-Pérez, M; Karlsson, L; Hernández, F; Rubio, C; Hernández-Armas, J; Hardisson, A

    2009-09-01

    This study analyzed the content of gamma-emitting radionuclides in fish farmed on the island of Tenerife (Canary Islands, Spain). The fish species included in this study were sea bass, gilthead bream, and rainbow trout. The first two species are produced in offshore enclosures, while the third is produced in a freshwater fish farm. All measurements were performed using two high-purity germanium gamma-ray detectors. The content of gamma-emitting radionuclides in the fodder used to feed the different species of farmed fish studied was also determined. The following nuclides were often detected in the analyzed samples: 137Cs, 40K, 235U, 228Ac, 214Bi, 208Tl, 212Pb, and 214Pb. As a complement to this analysis, 210Po concentrations in two fish samples were determined by alpha spectrometry. The nuclide presenting the highest concentration was, as expected, the naturally occurring 40K, with an average concentration of 0.13 +/- 0.01 Bq/g (wet weight) (Bq/gww) in gilthead bream and sea bass and 0.12 +/- 0.01 Bq/gww in rainbow trout. The 235U concentrations determined in the same fish species were 0.6 +/- 0.5, 0.8 +/- 0.7, and 1.6 +/- 1.0 mBq/gww, respectively. This nuclide is seldom reported in fish samples. The concentrations of 137Cs (the only artificial nuclide determined in this study) in gilthead bream and sea bass were 0.026 +/- 0.006 and 0.044 +/- 0.01 mBq/gww, respectively. In addition to the radiometric analysis, the contribution of the analyzed nuclides to the effective dose from the mean daily intake of the fish was calculated. The calculated contribution, in terms of dose per person, produced by intake of the analyzed fish was 0.8 microSv/year. This value does not represent a significant risk to the local population. PMID:19777898

  20. Preliminary Assessment of Suomi-NPP VIIRS On-orbit Radiometric Performance

    NASA Technical Reports Server (NTRS)

    Oudrari, Hassan; DeLuccia, Frank; McIntire, Jeff; Moyer, David; Chiang, Vincent; Xiong, Xiao-xiong; Butler, James

    2012-01-01

    The Visible-Infrared Imaging Radiometer Suite (VIIRS) is a key instrument on-board the Suomi National Polar-orbiting Partnership (NPP) spacecraft that was launched on October 28th 2011. VIIRS was designed to provide moderate and imaging resolution of most of the globe twice daily. It is a wide-swath (3,040 km) cross-track scanning radiometer with spatial resolutions of 370.and 740 m at nadir for imaging and moderate bands, respectively. It has 22 spectral bands covering the spectrum between 0.412 11m and 12.01 11m, including 14 reflective solar bands (RSB), 7 thermal emissive bands (TEB), and 1 day-night band (ON B). VIIRS observations are used to generate 22 environmental data products (EORs). This paper will briefly describe NPP VIIRS calibration strategies performed by the independent government team, for the initial on-orbit Intensive Calibration and Validation (ICV) activities. In addition, this paper will provide an early assessment of the sensor on-orbit radiometric performance, such as the sensor signal to noise ratios (SNRs), dual gain transition verification, dynamic range and linearity, reflective bands calibration based on the solar diffuser (SO) and solar diffuser stability monitor (SOSM), and emissive bands calibration based on the on-board blackbody calibration (OBC). A comprehensive set of performance metrics generated during the pre-launch testing program will be compared to VIIRS on-orbit early performance, and a plan for future cal/val activities and performance enhancements will be presented.

  1. Within-Scene Radiometric Correction Of LANDSAT Thematic Mapper (TM) Data In Canadian Production Systems

    NASA Astrophysics Data System (ADS)

    Murphy, Jennifer M.

    1986-11-01

    The Canada Centre for Remote Sensing (CCRS) has been using the scene-statistics approach, originally implemented in 19751 for destriping LANDSAT MSS data, for the routine correction of LANDSAT Thematic Mapper (TM) reflective band data. The 0.8% within-scene radiometric accuracy specified for Canadian production systems has been achieved for all but a small percentage of requested scenes2. A significant functionality of the processing methodology includes the correction for dark signal (DC) level shifts as a function of both detector and scan line number, by utilizing background reference level measurements available during the calibration period of each mirror scanning sequence. Additionally, forward and reverse mirror scans are treated independently. The effect of extended, bright targets such as snow, ice or clouds, is to cause a lowering of the background level by as much as 4 digital numbers (DN), with recovery times equivalent to approximately 2000 pixels. Hence, in the vicinity of the target itself, localized banding in phase with forward and reverse mirror sweeps is evident. A two-fold impact to the CCRS processing system occurs when the bright targets are at the edge of the scene, since the background reference level measured during the calibration period does not represent the offset for the imaging period of the sequence. The effects are, firstly, a more pronounced banding in those scan lines which image the bright target, and secondly, a forward/reverse banding superimposed over the entire scene, causing these scenes to fail the accuracy criterion. An automated procedure has therefore been adopted to detect when the forward/reverse banding would be outside specifications using the standard techniques. In such cases, forward and reverse mirror sweeps are then corrected with identical gain and offset correction parameters and the DC level shift corrections are applied.

  2. On-orbit performance of the Landsat-7 ETM+ radiometric calibrators

    USGS Publications Warehouse

    Markham, Brian L; Barker, J. L.; Kaita, E.; Seiferth, J.; Morfitt, Ron

    2003-01-01

    The Landsat-7 Enhanced Thematic Mapper Plus (ETM+) incorporates two new devices to improve its absolute radiometric calibration: a Full Aperture Solar Calibrator (FASC) and a Partial Aperture Solar Calibrator (PASC). The FASC is a diffuser panel, typically deployed once per month. Initial FASC absolute calibration results were within 5% of the pre-launch calibrations. Over time, the responses of the ETM+ to the FASC have varied with the location viewed on the panel, suggesting a localized degradation or contamination of the panel. On the best part of the panel, the trends in response range from m 1.4% y m 1 (band 4) to +0.6% y m 1 (band 7), with band 5 showing the least change at m 0.4% y m 1 . Changes in the panel reflectance due to UV exposure are believed to be the origin of these trends. The PASC is a set of auxiliary optics that allows the ETM+ to image the Sun through reduced apertures. PASC data have normally been acquired on a daily basis. Unlike the FASC, the PASC has exhibited significant anomalies. During the first six months of operation, responses to the PASC increased up to 60%, sending bands 2, 3 and 8 into saturation (band 1 was saturated at launch). The short-wave infrared (SWIR) band individual detectors have shown variations up to - 20% in response to the PASC. The variation is different for each detector. After the first six months, the responses to the PASC have become more stable, with much of the variation related to the within-scan position of the solar image. Overall results to date for all calibrators and comparisons with vicarious calibrations indicate that most of the response variations have been due to the calibrators themselves and suggest that the instrument has been stable with changes in response of less than 0.5% y m 1 .

  3. Landsat-7 ETM+: 12 years on-orbit reflective-band radiometric performance

    USGS Publications Warehouse

    Markham, B.L.; Haque, M.O.; Barsi, J.A.; Micijevic, E.; Helder, D.L.; Thome, K.J.; Aaron, D.; Czapla-Myers, J. S.

    2012-01-01

    The Landsat-7 ETM+ sensor has been operating on orbit for more than 12 years, and characterizations of its performance have been ongoing over this period. In general, the radiometric performance of the instrument has been remarkably stable: 1) noise performance has degraded by 2% or less overall, with a few detectors displaying step changes in noise of 2% or less; 2) coherent noise frequencies and magnitudes have generally been stable, though the within-scan amplitude variation of the 20 kHz noise in bands 1 and 8 disappeared with the failure of the scan line corrector and a new similar frequency noise (now about 18 kHz) has appeared in two detectors in band 5 and increased in magnitude with time; 3) bias stability has been better than 0.25 DN out of a normal value of 15 DN in high gain; 4) relative gains, the differences in response between the detectors in the band, have generally changed by 0.1% or less over the mission, with the exception of a few detectors with a step response change of 1% or less; and 5) gain stability averaged across all detectors in a band, which is related to the stability of the absolute calibration, has been more stable than the techniques used to measure it. Due to the inability to confirm changes in the gain (beyond a few detectors that have been corrected back to the band average), ETM+ reflective band data continues to be calibrated with the prelaunch measured gains. In the worst case, some bands may have changed as much as 2% in uncompensated absolute calibration over the 12 years.

  4. Updated radiometric calibration for the Landsat-5 thematic mapper reflective bands

    USGS Publications Warehouse

    Helder, D.L.; Markham, B.L.; Thome, K.J.; Barsi, J.A.; Chander, G.; Malla, R.

    2008-01-01

    The Landsat-5 Thematic Mapper (TM) has been the workhorse of the Landsat system. Launched in 1984, it continues collecting data through the time frame of this paper. Thus, it provides an invaluable link to the past history of the land features of the Earth's surface, and it becomes imperative to provide an accurate radiometric calibration of the reflective bands to the user community. Previous calibration has been based on information obtained from prelaunch, the onboard calibrator, vicarious calibration attempts, and cross-calibration with Landsat-7. Currently, additional data sources are available to improve this calibration. Specifically, improvements in vicarious calibration methods and development of the use of pseudoinvariant sites for trending provide two additional independent calibration sources. The use of these additional estimates has resulted in a consistent calibration approach that ties together all of the available calibration data sources. Results from this analysis indicate a simple exponential, or a constant model may be used for all bands throughout the lifetime of Landsat-5 TM. Where previously time constants for the exponential models were approximately one year, the updated model has significantly longer time constants in bands 1-3. In contrast, bands 4, 5, and 7 are shown to be best modeled by a constant. The models proposed in this paper indicate calibration knowledge of 5% or better early in life, decreasing to nearly 2% later in life. These models have been implemented at the U.S. Geological Survey Earth Resources Observation and Science (EROS) and are the default calibration used for all Landsat TM data now distributed through EROS. ?? 2008 IEEE.

  5. Absolute radiometric calibration of Landsat using a pseudo invariant calibration site

    USGS Publications Warehouse

    Helder, D.; Thome, K.J.; Mishra, N.; Chander, G.; Xiong, Xiaoxiong; Angal, A.; Choi, Tae-young

    2013-01-01

    Pseudo invariant calibration sites (PICS) have been used for on-orbit radiometric trending of optical satellite systems for more than 15 years. This approach to vicarious calibration has demonstrated a high degree of reliability and repeatability at the level of 1-3% depending on the site, spectral channel, and imaging geometries. A variety of sensors have used this approach for trending because it is broadly applicable and easy to implement. Models to describe the surface reflectance properties, as well as the intervening atmosphere have also been developed to improve the precision of the method. However, one limiting factor of using PICS is that an absolute calibration capability has not yet been fully developed. Because of this, PICS are primarily limited to providing only long term trending information for individual sensors or cross-calibration opportunities between two sensors. This paper builds an argument that PICS can be used more extensively for absolute calibration. To illustrate this, a simple empirical model is developed for the well-known Libya 4 PICS based on observations by Terra MODIS and EO-1 Hyperion. The model is validated by comparing model predicted top-of-atmosphere reflectance values to actual measurements made by the Landsat ETM+ sensor reflective bands. Following this, an outline is presented to develop a more comprehensive and accurate PICS absolute calibration model that can be Système international d'unités (SI) traceable. These initial concepts suggest that absolute calibration using PICS is possible on a broad scale and can lead to improved on-orbit calibration capabilities for optical satellite sensors.

  6. A comparison of four relative radiometric normalization (RRN) techniques for mosaicing H-res multi-temporal thermal infrared (TIR) flight-lines of a complex urban scene

    NASA Astrophysics Data System (ADS)

    Rahman, M. M.; Hay, G. J.; Couloigner, I.; Hemachandran, B.; Bailin, J.

    2015-08-01

    High-spatial and -radiometric resolution (H-res) thermal infrared (TIR) airborne imagery, such as the TABI-1800 (Thermal Airborne Broadband Imager) provide unique surface temperature information that can be used for urban heat loss mapping, heat island analysis, and landcover classifications. For mapping large urban areas at a high-spatial resolution (i.e., sub-meter), airborne thermal imagery needs to be acquired over a number of flight-lines and mosaiced together. However, due to radiometric variations between flight-lines the similar objects tend to have different temperature characteristics on the mosaicked image, resulting in reduced visual and radiometric agreement between the flight-lines composing the final mosaiced output. To reduce radiometric variability between airborne TIR flight-lines, with a view to produce a visually seamless TIR image mosaic, we evaluate four relative radiometric normalization techniques including: (i) Histogram Matching, (ii) Pseudo Invariant Feature (PIF) Based Linear Regression, (iii) PIF-Based Theil-Sen Regression, and (iv) No-Change Stratified Random Samples (NCSRS) Based Linear Regression. The techniques are evaluated on two adjacent TABI-1800 airborne flight-lines (each ∼30 km × 0.9 km) collected ∼25 min apart over a portion of The City of Calgary (with ∼30% overlap between them). The performances of these techniques are compared based on four criteria: (i) speed of computation, (ii) ability to automate, (iii) visual assessment, and (iv) statistical analysis. Results show that NCSRS-Based Linear Regression produces the best overall results closely followed by Histogram Matching. Specifically, these two radiometric normalization techniques: (i) increase the visual and statistical agreement between the tested TIR airborne flight-lines (NCSRS Based Linear Regression increases radiometric agreement between flight-lines by 53.3% and Histogram Matching by 52.4%), (ii) produce a visually seamless image mosaic, and (iii) can

  7. Mise en pratique for the definition of the candela and associated derived units for photometric and radiometric quantities in the International System of Units (SI)

    NASA Astrophysics Data System (ADS)

    Zwinkels, Joanne; Sperling, Armin; Goodman, Teresa; Campos Acosta, Joaquin; Ohno, Yoshi; Rastello, Maria Luisa; Stock, Michael; Woolliams, Emma

    2016-06-01

    The purpose of this mise en pratique, prepared by the Consultative Committee for Photometry and Radiometry (CCPR) of the International Committee for Weights and Measures (CIPM) and formally adopted by the CIPM, is to provide guidance on how the candela and related units used in photometry and radiometry can be realized in practice. The scope of the mise en pratique recognizes the fact that the two fields of photometry and radiometry and their units are closely related through the current definition of the SI base unit for the photometric quantity, luminous intensity: the candela. The previous version of the mise en pratique was applied only to the candela whereas this updated version covers the realization of the candela and other related units used for photometric and radiometric quantities. Recent advances in the generation and manipulation of individual photons show great promise of producing radiant fluxes with a well-established number of photons. Thus, this mise en pratique also includes information on the practical realization of units for photometric and radiometric quantities using photon-number-based techniques. In the following, for units used for photometric and radiometric quantities, the shorter term, photometric and radiometric units, is generally used. Section 1 describes the definition of the candela which introduces a close relationship between photometric and radiometric units. Sections 2 and 3 describe the practical realization of radiometric and photon-number-based units, respectively. Section 4.1 explains how, in general, photometric units are derived from radiometric units. Sections 4.2–4.5 deal with the particular geometric conditions for the specific photometric units. Section 5 deals very briefly with the topic of determination of measurement uncertainties in photometry.

  8. [Serum resistance of Escherichia coli in chronic pyelonephritis. 1. Serum resistance in the human serum pool].

    PubMed

    Falkenhagen, U; Handschuck, I; Ulisko, I N; Ratiner YuA; Nimmich, W; Zingler, G; Naumann, G

    1984-07-01

    123 patients of the kidney department of the Clinic for Inner Medicine of Rostock University suffering from chronic pyelonephritis were taken into microbiological observation for between one and four years. 170 E. coli strains were bred from 59 patients with significant bacteriuria in the course of the disease and their serum resistence was determined with pooled human serum using Taylor's method. 78.24% of the strains examined were serum-sensitive, 11.18% intermediate and 10.59% serum-resistent. All strains were O-, K- and H-typed. 57.06% were successfully O-typed and were distributed over 40 O-serogroups. 24.12% were not typable and 18.82% were rough colonies. 86.50% of the resistent and intermediate strains strains were O-typable, 13.50% could not be typed. The significance of E. coli antigens (O, K, H) and serum resistence for the maintenance of a chronic infection is discussed. PMID:6385542

  9. Piezoelectric microcantilever serum protein detector

    NASA Astrophysics Data System (ADS)

    Capobianco, Joseph A.

    The development of a serum protein detector will provide opportunities for better screening of at-risk cancer patients, tighter surveillance of disease recurrence and better monitoring of treatment. An integrated system that can process clinical samples for a number of different types of biomarkers would be a useful tool in the early detection of cancer. Also, screening biomarkers such as antibodies in serum would provide clinicians with information regarding the patient's response to treatment. Therefore, the goal of this study is to develop a sensor which can be used for rapid, all-electrical, real-time, label-fee, in-situ, specific quantification of cancer markers, e.g., human epidermal receptor 2 (Her2) or antibodies, in serum. To achieve this end, piezoelectric microcantilever sensors (PEMS) were constructed using an 8 mum thick lead magnesium niobate-lead titanate (PMN-PT) freestanding film as the piezoelectric layer. The desired limit of detection is on the order of pg/mL. In order to achieve this goal the higher frequency lateral extension modes were used. Also, as the driving and sensing of the PEMS is electrical, the PEMS must be insulated in a manner that allows it to function in aqueous solutions. The insulation layer must also be compatible with standardized bioconjugation techniques. Finally, detection of both cancer antigens and antibodies in serum was carried out, and the results were compared to a standard commercialized protocol. PEMS have demonstrated the capability of detecting Her2 at a concentration of 5 pg/mL in diluted human serum (1:40) in less than 1 hour. The approach can be easily translated into the clinical setting because the sensitivity is more than sufficient for monitoring prognosis of breast cancer patients. In addition to Her2 detection, antibodies in serum were assayed in order to demonstrate the feasibility of monitoring the immune response for antibody-dependent cellular cytotoxicity (ADCC) in patients on antibody therapies

  10. Design and optimization of an ultra-wideband and compact microwave antenna for radiometric monitoring of brain temperature

    PubMed Central

    Maccarini, Paolo F.; Salahi, Sara; Oliveira, Tiago R.; Pereira, Pedro J. S.; Limão-Vieira, Paulo; Snow, Brent W.; Reudink, Doug; Stauffer, Paul R.

    2014-01-01

    We present the modeling efforts on antenna design and frequency selection to monitor brain temperature during prolonged surgery using non-invasive microwave radiometry. A tapered log-spiral antenna design is chosen for its wideband characteristics that allow higher power collection from deep brain. Parametric analysis with HFSS is used to optimize antenna performance for deep brain temperature sensing. Radiometric antenna efficiency (η) is evaluated in terms of the ratio of power collected from brain to total power received by the antenna. Anatomical information extracted from several adult computed tomography (CT) scans is used to establish design parameters for constructing an accurate layered 3D tissue phantom. This head phantom includes separate brain and scalp regions, with tissue equivalent liquids circulating at independent temperatures on either side of an intact skull. The optimized frequency band is 1.1–1.6 GHz producing an average antenna efficiency of 50.3% from a 2 turn log-spiral antenna. The entire sensor package is contained in a lightweight and low profile 2.8 cm diameter by 1.5 cm high assembly that can be held in place over the skin with an electromagnetic interference (EMI) shielding adhesive patch. The calculated radiometric equivalent brain temperature tracks within 0.4°C of measured brain phantom temperature when the brain phantom is lowered 10°C and then returned to original temperature (37°C) over a 4.6-hour experiment. The numerical and experimental results demonstrate that the optimized 2.5 cm log-spiral antenna is well suited for the non-invasive radiometric sensing of deep brain temperature. PMID:24759979

  11. In-flight UV and polarized-VL radiometric calibrations of the solar orbiter/METIS imaging coronagraph

    NASA Astrophysics Data System (ADS)

    Focardi, M.; Capobianco, G.; Andretta, V.; Sasso, C.; Romoli, M.; Landini, F.; Fineschi, S.; Pancrazzi, M.; Bemporad, A.; Nicolini, G.; Pucci, S.; Uslenghi, M.; Naletto, G.; Nicolosi, P.; Spadaro, D.; Teriaca, L.; SchuÌhle, U. H.; Antonucci, E.

    2014-07-01

    METIS is an innovative inverted occulted solar coronagraph capable of obtaining for the first time simultaneous imaging of the full corona in linearly polarized visible-light (580-640 nm) and narrow-band (+/- 10 nm) ultraviolet H I Ly-α (121.6 nm). It has been selected to fly aboard the Solar Orbiter1 spacecraft, whose launch is foreseen in July 2017. Thanks to its own capabilities and exploiting the peculiar opportunities offered by the Solar Orbiter planned orbit, METIS will address some of the still open issues in understanding the physical processes in the corona and inner heliosphere. The Solar Orbiter Nominal Mission Phase (NMP) will be characterized by three scientific observing windows per orbit and METIS will perform at least one in-flight calibration per observing window. The two imaging channels of METIS will be calibrated on ground and periodically checked, verified and re-calibrated in-flight. In particular, radiometric calibration images will be needed to determine the absolute brightness of the solar corona. For UV radiometric calibration a set of targets is represented by continuum-emitting early type bright stars (e.g. A and B spectral types) whose photospheres produce a bright far-ultraviolet continuum spectrum stable over long timescales. These stars represent an important reference standard not only for METIS in-flight calibrations but also for other Solar Orbiter instruments and they will be crucial for instruments cross-calibrations as well. For VL radiometric calibration, a set of linearly polarized stars will be used. These targets shall have a minimum degree of linear polarization (DoLP > 5%) and a detectable magnitude, compatible with the instrument integration times constrained by the desired S/N ratio and the characteristics of the spacecraft orbit dynamics.

  12. Exploring a Black Body Source as an Absolute Radiometric Calibration Standard and Comparison with a NIST Traced Lamp Standard

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Chrien, Thomas; Sarture, Chuck

    2001-01-01

    Radiometric calibration of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) is required for the scientific research and application objectives pursued with the spectroscopic measurements. Specifically calibration is required for: inter-comparison of AVIRIS data measured at different locations and at different times; analysis of AVIRIS data with data measured by other instruments; and analysis of AVIRIS data in conjunction with computer models. The primary effect of radiometric calibration is conversion of AVIRIS instrument response values (digitized numbers, or DN) to units of absolute radiance. For example, a figure shows the instrument response spectrum measured by AVIRIS over a portion of Rogers Dry Lake, California, and another figure shows the same spectrum calibrated to radiance. Only the calibrated spectrum may be quantitatively analyzed for science research and application objectives. Since the initial development of the AVIRIS instrument-radiometric calibration has been based upon a 1000-W irradiance lamp with a calibration traced to the National Institute of Standards and Technology (NIST). There are several advantages to this irradiance-lamp calibration approach. First, the considerable effort of NIST backs up the calibration. Second, by changing the distance to the lamp, the output can closely span the radiance levels measured by AVIRIS. Third, this type of standard is widely used. Fourth, these calibrated lamps are comparatively inexpensive. Conversely, there are several disadvantages to this approach as well. First, the lamp is not a primary standard. Second, the lamp output characteristics may change in an unknown manner through time. Third, it is difficult to assess, constrain, or improve the calibration uncertainty delivered with the lamp. In an attempt to explore the effect and potentially address some of these disadvantages a set of analyses and measurements comparing an irradiance lamp with a black-body source have been completed

  13. Radiometric dating of Ochoan (Permian) evaporites, WIPP (Waste Isolation Pilot Plant) site, Delaware Basin, New Mexico, USA

    SciTech Connect

    Brookins, D.G.; Lambert, S.J.

    1986-01-01

    We have attempted radiometric dating of halide-sulfate salts and clay minerals from the Delaware Basin, New Mexico, USA, as part of geochemical study of the stability of the evaporite sequence at the WIPP (Waste Isolation Pilot Plant - a US DOE facilty) site. We undertook this dating to determine: (1) primary age of evaporite genesis or time(s) of recrystallization; (2) if previously undated evaporite minerals (leonite, polyhalite, kieserite) give useful data; and (3) if the detrital clay minerals have been radiometrically reset at any time following their incorporation into the evaporite medium. We have shown earlier that polyhalites can indeed be successfully dated by the K-Ar method, and once corrections are applied for admixed halide minerals, dates of 210-230 Ma for the Delaware Basin are obtained. Rb-Sr isochrons from early stage sylvites-polyhalites- anhydrites yield 220 +- 10 Ma, even when some sylvites yield lower K-Ar dates due to loss of *40-Ar. K-Ar dates on leonites and kieserities are also low due to *40-Ar loss, but their Rb-Sr dates are higher. Detrital clay minerals from the Delaware Basin collectively yield a highly scattered isochron (390 +- 77 Ma), but samples from a local area, such as the WIPP Site, give a much better age of 428 +- 7 Ma. These dates show that the interaction between the clay minerals and the evaporitic brines was insufficient to reset the clay minerals Rb-Sr systematics. In a related study, we note that a dike emplaced into the evaporite at 34 Ma had only very limited effect on the intruded rocks; contact phenomena were all within 2 m of the dike. All of our geochemical (radio-metric and trace element) studies of the WIPP site argue for preservation of the isotopic and chemical integrity of the major minerals for the past 200 Ma.

  14. Patch Antenna for Measuring the Internal Temperature of Biological Objects Using the Near-Field Microwave Radiometric Method

    NASA Astrophysics Data System (ADS)

    Ubaichin, A.; Bespalko, A.; Filatov, A.; Alexeev, E.; Zhuk, G.

    2016-01-01

    The near-field microwave antenna with central frequency of 2.23 GHz has been designed and manufactured to be used as a part of the medical microwave radiometric system. Experimental studies of the reflection coefficient in different parts of the human body were conducted using the developed antenna. The experimental studies were carried out in a group of volunteers with normal somatic growth. The results of the experiments were used to perform the analysis of the potential errors in the measurements obtained via the developed antenna.

  15. Decay of the El Chichon perturbation to the stratospheric aerosol layer - Multispectral ground-based radiometric observations

    NASA Astrophysics Data System (ADS)

    Pearson, E. W.; Lebaron, B. A.; Michalsky, J. J.

    1988-01-01

    A 9-yr time series of multispectral radiometric observations taken at Rattlesnake Mountain Observatory is analyzed to determine the long-term behavior of the El Chichon-induced perturbation to the stratospheric aerosol layer. A technique for determining the volcanic enhancement is described. Time series data for the volcanic enhancement in stratospheric optical depth at wavelengths of 1010, 785, 535, 486, and 428 nm are presented. The main features of the results, slight wavelength dependence and a seasonal oscillation superimposed on the expected exponential decay at all wavelengths, are discussed.

  16. Temperature measurements behind reflected shock waves in air. [radiometric measurement of gas temperature in self-absorbing gas flow

    NASA Technical Reports Server (NTRS)

    Bader, J. B.; Nerem, R. M.; Dann, J. B.; Culp, M. A.

    1972-01-01

    A radiometric method for the measurement of gas temperature in self-absorbing gases has been applied in the study of shock tube generated flows. This method involves making two absolute intensity measurements at identical wavelengths, but for two different pathlengths in the same gas sample. Experimental results are presented for reflected shock waves in air at conditions corresponding to incident shock velocities from 7 to 10 km/s and an initial driven tube pressure of 1 torr. These results indicate that, with this technique, temperature measurements with an accuracy of + or - 5 percent can be carried out. The results also suggest certain facility related problems.

  17. Apparatus description and data analysis of a radiometric technique for measurements of spectral and total normal emittance

    NASA Technical Reports Server (NTRS)

    Edwards, S. F.; Kantsios, A. G.; Voros, J. P.; Stewart, W. F.

    1975-01-01

    The development of a radiometric technique for determining the spectral and total normal emittance of materials heated to temperatures of 800, 1100, and 1300 K by direct comparison with National Bureau of Standards (NBS) reference specimens is discussed. Emittances are measured over the spectral range of 1 to 15 microns and are statistically compared with NBS reference specimens. Results are included for NBS reference specimens, Rene 41, alundum, zirconia, AISI type 321 stainless steel, nickel 201, and a space-shuttle reusable surface insulation.

  18. The Moon Mineralogy (M3) Imaging Spectrometer: Early Assessment of the Spectral, Radiometric, Spatial and Uniformity Properties

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Pieters, C. M.; Boardman, J.; Barr, D.; Bruce, C.; Bousman, J.; Chatterjee, A.; Eastwood, M.; Essandoh, V.; Geier, S.; Glavich, T.; Green, R.; Haemmerle, V.; Hyman, S.; Hovland, L.; Koch, T.; Lee, K.; Lundeen, S.; Motts, E.; Mouroulis, P.; Paulson, S.; Plourde, K.; Racho, C.; Robinson, D.; Rodriquez, J.

    2009-01-01

    The Moon Mineralogy Mapper's (M3) is a high uniformity and high signal-to-noise ratio NASA imaging spectrometer that is a guest instrument on the Indian Chandrayaan-1 Mission to the Moon. The laboratory measured spectral, radiometric, spatial, and uniformity characteristics of the M3 instrument are given. The M3 imaging spectrometer takes advantage of a suite of critical enabling capabilities to achieve its measurement requirement with a mass of 8 kg, power usage of 15 W, and volume of 25X18X12 cm. The M3 detector and spectrometer are cooled by a multi-stage passive cooler. This paper presents early M3 performance assessment results.

  19. The effect of osmotic stabilizers on the radiometric detection of osmotically sensitive populations of some gram-negative bacteria

    SciTech Connect

    Martinez, O.V.; Malinin, T.I.

    1982-02-01

    The effect of four osmotic stabilizers on the radiometric detection of osmotically sensitive populations of E. coli, S. typhimurium, and E. cloacae was studied. The addition of sucrose, sorbitol, glycerol, or ethylene glycoll to BACTEC 6B blood culture medium failed to improve the sensitivity of the system and produced an inhibitory effect on the level of 14CO2 released by organisms previously exposed to lysozyme and ECTA or to penicillin followed by the lysozyme treatment. The same effect was observed both in blood free media and simulated blood cultures. The addition of proline to sucrose-containing hypertonic media had no effect on growth index readings.

  20. Magnetostratigraphic and radiometric constraints on salt formation in the Qaidam Basin, NE Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wang, Jiuyi; Fang, Xiaomin; Appel, Erwin; Zhang, Weilin

    2013-10-01

    The Qaidam Basin is the largest Cenozoic intermontane basin within the northeast (NE) Tibetan Plateau. It contains large amounts of nonmarine evaporite deposits formed during the Pliocene-Quaternary. Even at present, extensive salt deposits dominated by halite and potash are formed by solar-driven concentration of brine water in the basin interior, making it the most important industrial base for potash exploitation in China. The formation of salt required an arid climatic, appropriate hydrological and tectonic setting through geologic times and will do so in the future. Studying the salt formation in the Qaidam Basin will enhance our understanding of processes driven by saline lake evolution, regional climate change, and tectonic movements, not only for the setting of the Tibetan Plateau. Reliable dating is crucial for assessing the time of salt formation in Qaidam Basin and the accumulation process, yet no comprehensive scientific studies have been reported on this important issue until now. In this paper, we critically review and compile magnetostratigraphic and radiometric studies of the salt-bearing strata within seven depressions of the basin. We find that the ages of salt formation are very different in these depressions: for the Dalangtan, Yiliping, Chahansilatu, and Kunteyi depressions, first salt deposits occurred at >3.90 ± 0.02 Ma, 2.88 ± 0.04 Ma, 2.24 ± 0.01 Ma and 1.18 ± 0.02 Ma, respectively. For the Mahai, Gasikule, and Qarhan, the ages of earliest salt formation are much younger i.e., 302 ± 56 ka, 608 ± 38 ka, and 54-24 ka, respectively. However, the result from Mahai has to be considered with caution. The variability of ages suggests an older salt-forming stage in the center of the western basin and a younger salt accumulation period along the basin margin. In a regional view, previous results from stratigraphy, sedimentology, geomorphology, and tectonic history allow us to conclude that the salt formation in the Qaidam Basin was probably