WorldWideScience

Sample records for radiometric calibration procedure

  1. Radiometric Calibration of Osmi Imagery Using Solar Calibration

    Directory of Open Access Journals (Sweden)

    Dong-Han Lee

    2000-12-01

    Full Text Available 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.

  2. The Pelindaba facility for calibrating radiometric field instruments

    International Nuclear Information System (INIS)

    Corner, B.; Toens, P.D.; Van As, D.; Vleggaar, C.M.; Richards, D.J.

    1979-04-01

    The tremendous upsurge in uranium exploration activity, experienced in recent years, has made the need for the standardisation and calibration of radiometric field instruments apparent. In order to fulfill this need, construction of a calibration facility at the National Nuclear Research Centre, Pelindaba, was commenced in 1972 and has since been extended according the the requirements of the mining industry. The facility currently comprises 11 surface standard sources suitable for the calibration, in terms of radio-element concentration, of portable scintillometers and spectrometers, and single uranium and thorium model-borehole sources which make possible the accurate calibration of borehole logging instruments both for gross-count and spectrometric surveys. Portable potassium, uranium and thorium sources are also available for the purposes of establishing airborne-spectrometer stripping ratios. The relevant physico-chemical properties of the standards are presented in this report and calibration procedures and data reduction techniques recommended. Examples are given of in situ measurements, both on surface and down-the-hole, which show that the derived calibration constants yield radiometric grades which are, on average, accurate to within 5% of the true radio-element concentrations. A secondary facility comprising single borehole- and surface-uranium sources has also been constructed in Beaufort West in the southern Karoo [af

  3. Geometric Calibration and Radiometric Correction of LiDAR Data and Their Impact on the Quality of Derived Products

    Directory of Open Access Journals (Sweden)

    Wai-Yeung Yan

    2011-09-01

    Full Text Available 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.

  4. RADIOMETRIC CALIBRATION OF AIRBORNE LASER SCANNING DATA

    OpenAIRE

    Pilarska Magdalena

    2016-01-01

    Airborne laser scanning (ALS) is widely used passive remote sensing technique. The radiometric calibration of ALS data is presented in this article. This process is a necessary element in data processing since it eliminates the influence of the external factors on the obtained values of radiometric features such as range and incidence angle. The datasets were captured with three different laser scanners; since each of these operates at a different wavelength (532, 106 4 and 1550 nm) th...

  5. RADIOMETRIC CALIBRATION OF MARS HiRISE HIGH RESOLUTION IMAGERY BASED ON FPGA

    Directory of Open Access Journals (Sweden)

    Y. Hou

    2016-06-01

    Full Text Available 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.

  6. Geometric Calibration and Radiometric Correction of the Maia Multispectral Camera

    Science.gov (United States)

    Nocerino, E.; Dubbini, M.; Menna, F.; Remondino, F.; Gattelli, M.; Covi, D.

    2017-10-01

    Multispectral imaging is a widely used remote sensing technique, whose applications range from agriculture to environmental monitoring, from food quality check to cultural heritage diagnostic. A variety of multispectral imaging sensors are available on the market, many of them designed to be mounted on different platform, especially small drones. This work focuses on the geometric and radiometric characterization of a brand-new, lightweight, low-cost multispectral camera, called MAIA. The MAIA camera is equipped with nine sensors, allowing for the acquisition of images in the visible and near infrared parts of the electromagnetic spectrum. Two versions are available, characterised by different set of band-pass filters, inspired by the sensors mounted on the WorlView-2 and Sentinel2 satellites, respectively. The camera details and the developed procedures for the geometric calibrations and radiometric correction are presented in the paper.

  7. A design of an on-orbit radiometric calibration device for high dynamic range infrared remote sensors

    Science.gov (United States)

    Sheng, Yicheng; Jin, Weiqi; Dun, Xiong; Zhou, Feng; Xiao, Si

    2017-10-01

    With the demand of quantitative remote sensing technology growing, high reliability as well as high accuracy radiometric calibration technology, especially the on-orbit radiometric calibration device has become an essential orientation in term of quantitative remote sensing technology. In recent years, global launches of remote sensing satellites are equipped with innovative on-orbit radiometric calibration devices. In order to meet the requirements of covering a very wide dynamic range and no-shielding radiometric calibration system, we designed a projection-type radiometric calibration device for high dynamic range sensors based on the Schmidt telescope system. In this internal radiometric calibration device, we select the EF-8530 light source as the calibration blackbody. EF-8530 is a high emittance Nichrome (Ni-Cr) reference source. It can operate in steady or pulsed state mode at a peak temperature of 973K. The irradiance from the source was projected to the IRFPA. The irradiance needs to ensure that the IRFPA can obtain different amplitude of the uniform irradiance through the narrow IR passbands and cover the very wide dynamic range. Combining the internal on-orbit radiometric calibration device with the specially designed adaptive radiometric calibration algorithms, an on-orbit dynamic non-uniformity correction can be accomplished without blocking the optical beam from outside the telescope. The design optimizes optics, source design, and power supply electronics for irradiance accuracy and uniformity. The internal on-orbit radiometric calibration device not only satisfies a series of indexes such as stability, accuracy, large dynamic range and uniformity of irradiance, but also has the advantages of short heating and cooling time, small volume, lightweight, low power consumption and many other features. It can realize the fast and efficient relative radiometric calibration without shielding the field of view. The device can applied to the design and

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

    Science.gov (United States)

    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

    2016-03-02

    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.

  9. A review of recent developments in radiometric calibration facilities

    International Nuclear Information System (INIS)

    Corner, B.

    1984-01-01

    Two new developments concerning radiometric calibration facilities are described in this presentation. The first is the result of the international programme for the monitoring and cross-reference of existing calibration facilities, sponsored by the International Atomic Energy Agency. The second development that is discussed concerns the accuracy of the stripping ratios derived at Pelindaba and has important implications for in situ assaying

  10. Vicarious absolute radiometric calibration of GF-2 PMS2 sensor using permanent artificial targets in China

    Science.gov (United States)

    Liu, Yaokai; Li, Chuanrong; Ma, Lingling; Wang, Ning; Qian, Yonggang; Tang, Lingli

    2016-10-01

    GF-2, launched on August 19 2014, is one of the high-resolution land resource observing satellite of the China GF series satellites plan. The radiometric performance evaluation of the onboard optical pan and multispectral (PMS2) sensor of GF-2 satellite is very important for the further application of the data. And, the vicarious absolute radiometric calibration approach is one of the most useful way to monitor the radiometric performance of the onboard optical sensors. In this study, the traditional reflectance-based method is used to vicarious radiometrically calibrate the onboard PMS2 sensor of GF-2 satellite using three black, gray and white reflected permanent artificial targets located in the AOE Baotou site in China. Vicarious field calibration campaign were carried out in the AOE-Baotou calibration site on 22 April 2016. And, the absolute radiometric calibration coefficients were determined with in situ measured atmospheric parameters and surface reflectance of the permanent artificial calibration targets. The predicted TOA radiance of a selected desert area with our determined calibrated coefficients were compared with the official distributed calibration coefficients. Comparison results show a good consistent and the mean relative difference of the multispectral channels is less than 5%. Uncertainty analysis was also carried out and a total uncertainty with 3.87% is determined of the TOA radiance.

  11. Laboratory-Based BRDF Calibration of Radiometric Tarps

    Science.gov (United States)

    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.

  12. English/Russian terminology on radiometric calibration of space-borne optoelectronic sensors

    Science.gov (United States)

    Privalsky, V.; Zakharenkov, V.; Humpherys, T.; Sapritsky, V.; Datla, R.

    The efficient use of data acquired through exo-atmospheric observations of the Earth within the framework of existing and newly planned programs requires a unique understanding of respective terms and definitions. Yet, the last large-scale document on the subject - The International Electrotechnical Vocabulary - had been published 18 years ago. This lack of a proper document, which would reflect the changes that had occurred in the area since that time, is especially detrimental to the developing international efforts aimed at global observations of the Earth from space such as the Global Earth Observations Program proposed by the U.S.A. at the 2003 WMO Congress. To cover this gap at least partially, a bi-lingual explanatory dictionary of terms and definitions in the area of radiometric calibration of space-borne IR sensors is developed. The objectives are to produce a uniform terminology for the global space-borne observations of the Earth, establish a unique understanding of terms and definitions by the radiometric communities, including a correspondence between the Russian and American terms and definitions, and to develop a formal English/Russian reference dictionary for use by scientists and engineers involved in radiometric observations of the Earth from space. The dictionary includes close to 400 items covering basic concepts of geometric, wave and corpuscular optics, remote sensing technologies, and ground-based calibration as well as more detailed treatment of terms and definitions in the areas of radiometric quantities, symbols and units, optical phenomena and optical properties of objects and media, and radiometric systems and their properties. The dictionary contains six chapters: Basic Concepts, Quantities, Symbols, and Units, Optical phenomena, Optical characteristics of surfaces and media, Components of Radiometric Systems, Characteristics of radiometric system components, plus English/Russian and Russian/Inglish indices.

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

    Science.gov (United States)

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

    2015-11-06

    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.

  14. Radiometric calibration of digital cameras using neural networks

    Science.gov (United States)

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

    2017-08-01

    Digital cameras are used in a large variety of scientific and industrial applications. For most applications, the acquired data should represent the real light intensity per pixel as accurately as possible. However, digital cameras are subject to physical, electronic and optical effects that lead to errors and noise in the raw image. Temperature- dependent dark current, read noise, optical vignetting or different sensitivities of individual pixels are examples of such effects. The purpose of radiometric calibration is to improve the quality of the resulting images by reducing the influence of the various types of errors on the measured data and thus improving the quality of the overall application. In this context, we present a specialized neural network architecture for radiometric calibration of digital cameras. Neural networks are used to learn a temperature- and exposure-dependent mapping from observed gray-scale values to true light intensities for each pixel. In contrast to classical at-fielding, neural networks have the potential to model nonlinear mappings which allows for accurately capturing the temperature dependence of the dark current and for modeling cameras with nonlinear sensitivities. Both scenarios are highly relevant in industrial applications. The experimental comparison of our network approach to classical at-fielding shows a consistently higher reconstruction quality, also for linear cameras. In addition, the calibration is faster than previous machine learning approaches based on Gaussian processes.

  15. A COMPARISON OF LIDAR REFLECTANCE AND RADIOMETRICALLY CALIBRATED HYPERSPECTRAL IMAGERY

    Directory of Open Access Journals (Sweden)

    A. Roncat

    2016-06-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    Science.gov (United States)

    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

  18. Calibrated infrared ground/air radiometric spectrometer

    Science.gov (United States)

    Silk, J. K.; Schildkraut, Elliot Robert; Bauldree, Russell S.; Goodrich, Shawn M.

    1996-06-01

    The calibrated infrared ground/air radiometric spectrometer (CIGARS) is a new high performance, multi-purpose, multi- platform Fourier transform spectrometer (FPS) sensor. It covers the waveband from 0.2 to 12 micrometer, has spectral resolution as fine as 0.3 cm-1, and records over 100 spectra per second. Two CIGARS units are being used for observations of target signatures in the air or on the ground from fixed or moving platforms, including high performance jet aircraft. In this paper we describe the characteristics and capabilities of the CIGARS sensor, which uses four interchangeable detector modules (Si, InGaAs, InSb, and HgCdTe) and two optics modules, with internal calibration. The data recording electronics support observations of transient events, even without precise information on the timing of the event. We present test and calibration data on the sensitivity, spectral resolution, stability, and spectral rate of CIGARS, and examples of in- flight observations of real targets. We also discuss plans for adapting CIGARS for imaging spectroscopy observations, with simultaneous spectral and spatial data, by replacing the existing detectors with a focal plane array (FPA).

  19. Radiometric Cross-Calibration of GF-4 in Multispectral Bands

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    Aixia Yang

    2017-03-01

    Full Text Available The GaoFen-4 (GF-4, launched at the end of December 2015, is China’s first high-resolution geostationary optical satellite. A panchromatic and multispectral sensor (PMS is onboard the GF-4 satellite. Unfortunately, the GF-4 has no onboard calibration assembly, so on-orbit radiometric calibration is required. Like the charge-coupled device (CCD onboard HuanJing-1 (HJ or the wide field of view sensor (WFV onboard GaoFen-1 (GF-1, GF-4 also has a wide field of view, which provides challenges for cross-calibration with narrow field of view sensors, like the Landsat series. A new technique has been developed and used to calibrate HJ-1/CCD and GF-1/WFV, which is verified viable. The technique has three key steps: (1 calculate the surface using the bi-directional reflectance distribution function (BRDF characterization of a site, taking advantage of its uniform surface material and natural topographic variation using Landsat Enhanced Thematic Mapper Plus (ETM+/Operational Land Imager (OLI imagery and digital elevation model (DEM products; (2 calculate the radiance at the top-of-the atmosphere (TOA with the simulated surface reflectance using the atmosphere radiant transfer model; and (3 fit the calibration coefficients with the TOA radiance and corresponding Digital Number (DN values of the image. This study attempts to demonstrate the technique is also feasible to calibrate GF-4 multispectral bands. After fitting the calibration coefficients using the technique, extensive validation is conducted by cross-validation using the image pairs of GF-4/PMS and Landsat-8/OLI with similar transit times and close view zenith. The validation result indicates a higher accuracy and frequency than that given by the China Centre for Resources Satellite Data and Application (CRESDA using vicarious calibration. The study shows that the new technique is also quite feasible for GF-4 multispectral bands as a routine long-term procedure.

  20. THE FUTURE SPACEBORNE HYPERSPECTRAL IMAGER ENMAP: ITS IN-FLIGHT RADIOMETRIC AND GEOMETRIC CALIBRATION CONCEPT

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    M. Schneider

    2012-07-01

    Full Text Available 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

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

    Science.gov (United States)

    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. Absolute radiometric calibration of Landsat using a pseudo invariant calibration site

    Science.gov (United States)

    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.

  3. Radiometric calibration of the in-flight blackbody calibration system of the GLORIA interferometer

    Directory of Open Access Journals (Sweden)

    C. Monte

    2014-01-01

    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.

  4. Air Kerma above environmental radiometric calibration facility for field equipment

    International Nuclear Information System (INIS)

    Conti, C.C.; Sachett, I.A.; Bertelli, L.; Lopes, R.T.

    2000-01-01

    The use of gamma ray spectrometers broadened the aims of gamma ray surveys, stead of measuring only the gross radiation, as was done with the GM tubes, it is now possible to be used for uranium exploration, geological mapping as an aid to the exploration of non radioactive ores like gold and tin, radiation background measurements to identify hot spots for radiation hazard evaluation and environmental monitoring of fallout from radiological and nuclear accidents. It became necessary to carefully and precisely calibrate the field equipment to be used to get all the information from such uses. There is an environmental radiometric calibration facility for field equipment, consisting of eight radioactive concrete sources, at the Institute of Radioprotection and Dosimetry - IRD (CNEN/Brazil). These sources are cylindrical with 3 m diameter, 0.5 m thick and weigh about 7.5 tons each. The amount and type of the radioactive material, 238 U and 232 Th and 40 K ores in secular radioactive equilibrium, added to the concrete to simulate rock outcrops, varies in order to obtain different gamma fields, varying in both energy and intensity. These different radiation fields were measured with a HPGe portable detector, specifically calibrated for spectrum stripping, and the air kerma energy distribution was determined for each concrete source and compared with the total air kerma calculated from the nuclide concentration and by others radiometric methods. (author)

  5. Spectrally and Radiometrically Stable Wide-Band on Board Calibration Source for In-Flight Data Validation in Imaging Spectroscopy Applications

    Science.gov (United States)

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

    2011-01-01

    The quality of the quantitative spectral data collected by an imaging spectrometer instrument is critically dependent upon the accuracy of the spectral and radiometric calibration of the system. In order for the collected spectra to be scientifically useful, the calibration of the instrument must be precisely known not only prior to but during data collection. Thus, in addition to a rigorous in-lab calibration procedure, the airborne instruments designed and built by the NASA/JPL Imaging Spectroscopy Group incorporate an on board calibrator (OBC) system with the instrument to provide auxiliary in-use system calibration data. The output of the OBC source illuminates a target panel on the backside of the foreoptics shutter both before and after data collection. The OBC and in-lab calibration data sets are then used to validate and post-process the collected spectral image data. The resulting accuracy of the spectrometer output data is therefore integrally dependent upon the stability of the OBC source. In this paper we describe the design and application of the latest iteration of this novel device developed at NASA/JPL which integrates a halogen-cycle source with a precisely designed fiber coupling system and a fiber-based intensity monitoring feedback loop. The OBC source in this Airborne Testbed Spectrometer was run over a period of 15 hours while both the radiometric and spectral stabilities of the output were measured and demonstrated stability to within 1% of nominal.

  6. A Study on Relative Radiometric Calibration without Calibration Field for YG-25

    Directory of Open Access Journals (Sweden)

    ZHANG Guo

    2017-08-01

    Full Text Available YG-25 is the first agility optical remote sensing satellite of China to acquire the sub-meter imagery of the earth. The side slither calibration technique is an on-orbit maneuver that has been used to flat-field image data acquired over the uniform calibration field. However, imaging to the single uniform calibration field cannot afford to calibrate the full dynamic response range of the sensor and reduces the efficiency. The paper proposes a new relative radiometric calibration method that a 90-degree yaw maneuver is performed over any non-uniform features of the Earth for YG-25. Meanwhile, we use an enhanced side slither image horizontal correction method based on line segment detector(LSDalgorithm to solve the side slither image over-shifted problem.The shifted results are compared with other horizontal correction method. The histogram match algorithm is used to calculate the relative gains of all detectors. The correctness and validity of the proposed method are validated by using the YG-25 on-board side slither data. The results prove that the mean streaking metrics of relative correction images of YG-25 is better 0.07%, the noticeable striping artifact and residual noise are removed, the calibration accuracy of side slither technique based on non-uniform features is superior to life image statistics of sensor's life span.

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

    Science.gov (United States)

    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.

  8. Radiometric and spectral calibrations of the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) using principle component analysis

    Science.gov (United States)

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

    2008-10-01

    The ultimate remote sensing benefits of the high resolution Infrared radiance spectrometers will be realized with their geostationary satellite implementation in the form of imaging spectrometers. This will enable dynamic features of the atmosphere's thermodynamic fields and pollutant and greenhouse gas constituents to be observed for revolutionary improvements in weather forecasts and more accurate air quality and climate predictions. As an important step toward realizing this application objective, the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) Engineering Demonstration Unit (EDU) was successfully developed under the NASA New Millennium Program, 2000-2006. The GIFTS-EDU instrument employs three focal plane arrays (FPAs), which gather measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The raw GIFTS interferogram measurements are radiometrically and spectrally calibrated to produce radiance spectra, which are further processed to obtain atmospheric profiles via retrieval algorithms. The radiometric calibration is achieved using internal blackbody calibration references at ambient (260 K) and hot (286 K) temperatures. The absolute radiometric performance of the instrument is affected by several factors including the FPA off-axis effect, detector/readout electronics induced nonlinearity distortions, and fore-optics offsets. The GIFTS-EDU, being the very first imaging spectrometer to use ultra-high speed electronics to readout its large area format focal plane array detectors, operating at wavelengths as large as 15 microns, possessed non-linearity's not easily removable in the initial calibration process. In this paper, we introduce a refined calibration technique that utilizes Principle Component (PC) analysis to compensate for instrument distortions and artifacts remaining after the initial radiometric calibration process, thus, further enhance the absolute calibration accuracy. This method is

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

    Directory of Open Access Journals (Sweden)

    Alireza G. Kashani

    2015-11-01

    Full Text Available 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.

  10. Temporal dynamics of sand dune bidirectional reflectance characteristics for absolute radiometric calibration of optical remote sensing data

    Science.gov (United States)

    Coburn, Craig A.; Logie, Gordon S. J.

    2018-01-01

    Attempts to use pseudoinvariant calibration sites (PICS) for establishing absolute radiometric calibration of Earth observation (EO) satellites requires high-quality information about the nature of the bidirectional reflectance distribution function (BRDF) of the surfaces used for these calibrations. Past studies have shown that the PICS method is useful for evaluating the trend of sensors over time or for the intercalibration of sensors. The PICS method was not considered until recently for deriving absolute radiometric calibration. This paper presents BRDF data collected by a high-performance portable goniometer system to develop a temporal BRDF model for the Algodones Dunes in California. By sampling the BRDF of the sand surface at similar solar zenith angles to those normally encountered by EO satellites, additional information on the changing nature of the surface can improve models used to provide absolute radiometric correction. The results demonstrated that the BRDF of a reasonably simple sand surface was complex with changes in anisotropy taking place in response to changing solar zenith angles. For the majority of observation and illumination angles, the spectral reflectance anisotropy observed varied between 1% and 5% in patterns that repeat around solar noon.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    1988-10-01

    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.

  13. SENSOR CORRECTION AND RADIOMETRIC CALIBRATION OF A 6-BAND MULTISPECTRAL IMAGING SENSOR FOR UAV REMOTE SENSING

    Directory of Open Access Journals (Sweden)

    J. Kelcey

    2012-07-01

    Full Text Available 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.

  14. Solar Tower Experiments for Radiometric Calibration and Validation of Infrared Imaging Assets and Analysis Tools for Entry Aero-Heating Measurements

    Science.gov (United States)

    Splinter, Scott C.; Daryabeigi, Kamran; Horvath, Thomas J.; Mercer, David C.; Ghanbari, Cheryl M.; Ross, Martin N.; Tietjen, Alan; Schwartz, Richard J.

    2008-01-01

    The NASA Engineering and Safety Center sponsored Hypersonic Thermodynamic Infrared Measurements assessment team has a task to perform radiometric calibration and validation of land-based and airborne infrared imaging assets and tools for remote thermographic imaging. The IR assets and tools will be used for thermographic imaging of the Space Shuttle Orbiter during entry aero-heating to provide flight boundary layer transition thermography data that could be utilized for calibration and validation of empirical and theoretical aero-heating tools. A series of tests at the Sandia National Laboratories National Solar Thermal Test Facility were designed for this task where reflected solar radiation from a field of heliostats was used to heat a 4 foot by 4 foot test panel consisting of LI 900 ceramic tiles located on top of the 200 foot tall Solar Tower. The test panel provided an Orbiter-like entry temperature for the purposes of radiometric calibration and validation. The Solar Tower provided an ideal test bed for this series of radiometric calibration and validation tests because it had the potential to rapidly heat the large test panel to spatially uniform and non-uniform elevated temperatures. Also, the unsheltered-open-air environment of the Solar Tower was conducive to obtaining unobstructed radiometric data by land-based and airborne IR imaging assets. Various thermocouples installed on the test panel and an infrared imager located in close proximity to the test panel were used to obtain surface temperature measurements for evaluation and calibration of the radiometric data from the infrared imaging assets. The overall test environment, test article, test approach, and typical test results are discussed.

  15. Uncertainty Evaluations of the CRCS In-orbit Field Radiometric Calibration Methods for Thermal Infrared Channels of FENGYUN Meteorological Satellites

    Science.gov (United States)

    Zhang, Y.; Rong, Z.; Min, M.; Hao, X.; Yang, H.

    2017-12-01

    Meteorological satellites have become an irreplaceable weather and ocean-observing tool in China. These satellites are used to monitor natural disasters and improve the efficiency of many sectors of Chinese national economy. It is impossible to ignore the space-derived data in the fields of meteorology, hydrology, and agriculture, as well as disaster monitoring in China, a large agricultural country. For this reason, China is making a sustained effort to build and enhance its meteorological observing system and application system. The first Chinese polar-orbiting weather satellite was launched in 1988. Since then China has launched 14 meteorological satellites, 7 of which are sun synchronous and 7 of which are geostationary satellites; China will continue its two types of meteorological satellite programs. In order to achieve the in-orbit absolute radiometric calibration of the operational meteorological satellites' thermal infrared channels, China radiometric calibration sites (CRCS) established a set of in-orbit field absolute radiometric calibration methods (FCM) for thermal infrared channels (TIR) and the uncertainty of this method was evaluated and analyzed based on TERRA/AQUA MODIS observations. Comparisons between the MODIS at pupil brightness temperatures (BTs) and the simulated BTs at the top of atmosphere using radiative transfer model (RTM) based on field measurements showed that the accuracy of the current in-orbit field absolute radiometric calibration methods was better than 1.00K (@300K, K=1) in thermal infrared channels. Therefore, the current CRCS field calibration method for TIR channels applied to Chinese metrological satellites was with favorable calibration accuracy: for 10.5-11.5µm channel was better than 0.75K (@300K, K=1) and for 11.5-12.5µm channel was better than 0.85K (@300K, K=1).

  16. The Importance of Post-Launch, On-Orbit Absolute Radiometric Calibration for Remote Sensing Applications

    Science.gov (United States)

    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

  17. Vicarious Radiometric Calibration of a Multispectral Camera on Board an Unmanned Aerial System

    Directory of Open Access Journals (Sweden)

    Susana Del Pozo

    2014-02-01

    Full Text Available Combinations of unmanned aerial platforms and multispectral sensors are considered low-cost tools for detailed spatial and temporal studies addressing spectral signatures, opening a broad range of applications in remote sensing. Thus, a key step in this process is knowledge of multi-spectral sensor calibration parameters in order to identify the physical variables collected by the sensor. This paper discusses the radiometric calibration process by means of a vicarious method applied to a high-spatial resolution unmanned flight using low-cost artificial and natural covers as control and check surfaces, respectively.

  18. Exploring a Black Body Source as an Absolute Radiometric Calibration Standard and Comparison with a NIST Traced Lamp Standard

    Science.gov (United States)

    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

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

    International Nuclear Information System (INIS)

    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 μm. The configuration of the LANL RCS. Two blackbody sources have been designed to cover the spectral range from about 3-15 μm, 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

  20. Design and use of concrete pads for the calibration of radiometric survey instrumentation

    International Nuclear Information System (INIS)

    Loevborg, L.

    1984-10-01

    A gamma-ray spectrometer for use in geological exploration possesses four stripping ratios and three window sensitivities which must be determined to make the instrumentation applicable for field assay or airborne measurement of potassium, uranium, and thorium contents in the ground. Survey organizations in many parts of the world perform the instrument calibration using large pads of concrete which simulate a plane ground of known radioelement concentration. Calibration and monitoring trials with twelve facilities in ten countries prove that moisture absorption, radon exhalation, and particle-size effects can offset a radiometric grade assigned to concrete whose aggregate contains an embedded radioactive mineral. These and other calibration problems are discussed from a combined theoretical and practical viewpoint

  1. Radiometric determination in situ of the face grades in Witwatersrand gold and uranium mines

    International Nuclear Information System (INIS)

    Smit, C.J.B.

    1985-01-01

    A prototype collimated radiometric face scanner was tested in the Harmony Gold Mine. The results obtained during the pilot study indicate that in situ radiometric uranium assays are statistically indistinguishable from those obtained conventionally from channel chip samples. In addition, the study demonstrated that reasonably reliable gold estimates can be deduced from the radiometric measurements, by use of the ratio of gold to uranium within a mine. The instrumentation, calibration procedures, and background determination are described briefly

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Absolute Radiometric Calibration of the GÖKTÜRK-2 Satellite Sensor Using Tuz GÖLÜ (landnet Site) from Ndvi Perspective

    Science.gov (United States)

    Sakarya, Ufuk; Hakkı Demirhan, İsmail; Seda Deveci, Hüsne; Teke, Mustafa; Demirkesen, Can; Küpçü, Ramazan; Feray Öztoprak, A.; Efendioğlu, Mehmet; Fehmi Şimşek, F.; Berke, Erdinç; Zübeyde Gürbüz, Sevgi

    2016-06-01

    TÜBİTAK UZAY has conducted a research study on the use of space-based satellite resources for several aspects of agriculture. Especially, there are two precision agriculture related projects: HASSAS (Widespread application of sustainable precision agriculture practices in Southeastern Anatolia Project Region (GAP) Project) and AKTAR (Smart Agriculture Feasibility Project). The HASSAS project aims to study development of precision agriculture practice in GAP region. Multi-spectral satellite imagery and aerial hyperspectral data along with ground measurements was collected to analyze data in an information system. AKTAR aims to develop models for irrigation, fertilization and spectral signatures of crops in Inner Anatolia. By the end of the project precision agriculture practices to control irrigation, fertilization, pesticide and estimation of crop yield will be developed. Analyzing the phenology of crops using NDVI is critical for the projects. For this reason, absolute radiometric calibration of the Red and NIR bands in space-based satellite sensors is an important issue. The Göktürk-2 satellite is an earth observation satellite which was designed and built in Turkey and was launched in 2012. The Göktürk-2 satellite sensor has a resolution 2.5 meters in panchromatic and 5 meters in R/G/B/NIR bands. The absolute radiometric calibration of the Göktürk-2 satellite sensor was performed via the ground-based measurements - spectra-radiometer, sun photometer, and meteorological station- in Tuz Gölü cal/val site in 2015. In this paper, the first ground-based absolute radiometric calibration results of the Göktürk-2 satellite sensor using Tuz Gölü is demonstrated. The absolute radiometric calibration results of this paper are compared with the published cross-calibration results of the Göktürk-2 satellite sensor utilizing Landsat 8 imagery. According to the experimental comparison results, the Göktürk-2 satellite sensor coefficients for red and NIR bands

  4. ABSOLUTE RADIOMETRIC CALIBRATION OF THE GÖKTÜRK-2 SATELLITE SENSOR USING TUZ GÖLÜ (LANDNET SITE FROM NDVI PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    U. Sakarya

    2016-06-01

    Full Text Available TÜBİTAK UZAY has conducted a research study on the use of space-based satellite resources for several aspects of agriculture. Especially, there are two precision agriculture related projects: HASSAS (Widespread application of sustainable precision agriculture practices in Southeastern Anatolia Project Region (GAP Project and AKTAR (Smart Agriculture Feasibility Project. The HASSAS project aims to study development of precision agriculture practice in GAP region. Multi-spectral satellite imagery and aerial hyperspectral data along with ground measurements was collected to analyze data in an information system. AKTAR aims to develop models for irrigation, fertilization and spectral signatures of crops in Inner Anatolia. By the end of the project precision agriculture practices to control irrigation, fertilization, pesticide and estimation of crop yield will be developed. Analyzing the phenology of crops using NDVI is critical for the projects. For this reason, absolute radiometric calibration of the Red and NIR bands in space-based satellite sensors is an important issue. The Göktürk-2 satellite is an earth observation satellite which was designed and built in Turkey and was launched in 2012. The Göktürk-2 satellite sensor has a resolution 2.5 meters in panchromatic and 5 meters in R/G/B/NIR bands. The absolute radiometric calibration of the Göktürk-2 satellite sensor was performed via the ground-based measurements - spectra-radiometer, sun photometer, and meteorological station- in Tuz Gölü cal/val site in 2015. In this paper, the first ground-based absolute radiometric calibration results of the Göktürk-2 satellite sensor using Tuz Gölü is demonstrated. The absolute radiometric calibration results of this paper are compared with the published cross-calibration results of the Göktürk-2 satellite sensor utilizing Landsat 8 imagery. According to the experimental comparison results, the Göktürk-2 satellite sensor coefficients for

  5. Providing radiometric traceability for the calibration home base of DLR by PTB

    Energy Technology Data Exchange (ETDEWEB)

    Taubert, D. R.; Hollandt, J.; Sperfeld, P.; Pape, S.; Hoepe, A.; Hauer, K.-O. [Physikalisch-Technische Bundesanstalt, Braunschweig und Berlin, 10587 Berlin (Germany); Gege, P.; Schwarzmaier, T.; Lenhard, K.; Baumgartner, A. [Deutsches Zentrum fuer Luft- und Raumfahrt, Institut fuer Methodik der Fernerkundung, 82234 Oberpfaffenhofen (Germany)

    2013-05-10

    A dedicated calibration technique was applied for the calibration of the spectral radiance transfer standard (RASTA) of the German Aerospace Center (DLR) at the Physikalisch-Technische Bundesanstalt (PTB), consisting of two independent but complementing calibration procedures to provide redundancy and smallest possible calibration uncertainties. Procedure I included two calibration steps: In a first step the optical radiation source of RASTA, an FEL lamp, was calibrated in terms of its spectral irradiance E{sub {lambda}}({lambda}) in the wavelength range from 350 nm to 2400 nm using the PTB Spectral Irradiance Calibration Equipment (SPICE), while in a second step the spectral radiance factor {beta}{sub 0 Degree-Sign :45 Degree-Sign }({lambda}) of the RASTA reflection standard was calibrated in a 0 Degree-Sign :45 Degree-Sign -viewing geometry in the wavelength range from 350 nm to 1700 nm at the robot-based gonioreflectometer facility of PTB. The achieved relative standard uncertainties (k= 1) range from 0.6 % to 3.2 % and 0.1 % to 0.6 % respectively. Procedure II was completely independent from procedure I and allowed to cover the entire spectral range of RASTA from 350 nm to 2500 nm. In the second procedure, the 0 Degree-Sign :45 Degree-Sign -viewing geometry spectral radiance L{sub {lambda},0 Degree-Sign :45 Degree-Sign }({lambda}) of RASTA was directly calibrated at the Spectral Radiance Comparator Facility (SRCF) of PTB. The relative uncertainties for this calibration procedure range from 0.8 % in the visible up to 7.5 % at 2500 nm (k= 1). In the overlapping spectral range of both calibration procedures the calculated spectral radiance L{sub {lambda},0 Degree-Sign :45 Degree-Sign ,calc}({lambda}) from procedure I is in good agreement with the direct measurement of procedure II, i.e. well within the combined expanded uncertainties (k= 2) of both procedures.

  6. RapidEye constellation relative radiometric accuracy measurement using lunar images

    Science.gov (United States)

    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. Level 0 to 1 processing of the imaging Fourier transform spectrometer GLORIA: generation of radiometrically and spectrally calibrated spectra

    Directory of Open Access Journals (Sweden)

    A. Kleinert

    2014-12-01

    Full Text Available The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA is an imaging Fourier transform spectrometer that is capable of operating on various high-altitude research aircraft. It measures the atmospheric emission in the thermal infrared spectral region in limb and nadir geometry. GLORIA consists of a classical Michelson interferometer combined with an infrared camera. The infrared detector has a usable area of 128 × 128 pixels, measuring up to 16 384 interferograms simultaneously. Imaging Fourier transform spectrometers impose a number of challenges with respect to instrument calibration and algorithm development. The optical setup with extremely high optical throughput requires the development of new methods and algorithms for spectral and radiometric calibration. Due to the vast amount of data there is a high demand for scientifically intelligent optimisation of the data processing. This paper outlines the characterisation and processing steps required for the generation of radiometrically and spectrally calibrated spectra. Methods for performance optimisation of the processing algorithm are presented. The performance of the data processing and the quality of the calibrated spectra are demonstrated for measurements collected during the first deployments of GLORIA on aircraft.

  8. Radiometric characterization of Landsat Collection 1 products

    Science.gov (United States)

    Micijevic, Esad; Haque, Md. Obaidul; Mishra, Nischal

    2017-09-01

    Landsat data in the U.S. Geological Survey (USGS) archive are being reprocessed to generate a tiered collection of consistently geolocated and radiometrically calibrated products that are suitable for time series analyses. With the implementation of the collection management, no major updates will be made to calibration of the Landsat sensors within a collection. Only calibration parameters needed to maintain the established calibration trends without an effect on derived environmental records will be regularly updated, while all other changes will be deferred to a new collection. This first collection, Collection 1, incorporates various radiometric calibration updates to all Landsat sensors including absolute and relative gains for Landsat 8 Operational Land Imager (OLI), stray light correction for Landsat 8 Thermal Infrared Sensor (TIRS), absolute gains for Landsat 4 and 5 Thematic Mappers (TM), recalibration of Landsat 1-5 Multispectral Scanners (MSS) to ensure radiometric consistency among different formats of archived MSS data, and a transfer of Landsat 8 OLI reflectance based calibration to all previous Landsat sensors. While all OLI/TIRS, ETM+ and majority of TM data have already been reprocessed to Collection 1, a completion of MSS and remaining TM data reprocessing is expected by the end of this year. It is important to note that, although still available for download from the USGS web pages, the products generated using the Pre-Collection processing do not benefit from the latest radiometric calibration updates. In this paper, we are assessing radiometry of solar reflective bands in Landsat Collection 1 products through analysis of trends in on-board calibrator and pseudo invariant site (PICS) responses.

  9. RADIOMETRIC BLOCK ADJUSMENT AND DIGITAL RADIOMETRIC MODEL GENERATION

    Directory of Open Access Journals (Sweden)

    A. Pros

    2013-05-01

    Full Text Available In this paper we present a radiometric block adjustment method that is related to geometric block adjustment and to the concept of a terrain Digital Radiometric Model (DRM as a complement to the terrain digital elevation and surface models. A DRM, in our concept, is a function that for each ground point returns a reflectance value and a Bidirectional Reflectance Distribution Function (BRDF. In a similar way to the terrain geometric reconstruction procedure, given an image block of some terrain area, we split the DRM generation in two phases: radiometric block adjustment and DRM generation. In the paper we concentrate on the radiometric block adjustment step, but we also describe a preliminary DRM generator. In the block adjustment step, after a radiometric pre-calibraton step, local atmosphere radiative transfer parameters, and ground reflectances and BRDFs at the radiometric tie points are estimated. This radiometric block adjustment is based on atmospheric radiative transfer (ART models, pre-selected BRDF models and radiometric ground control points. The proposed concept is implemented and applied in an experimental campaign, and the obtained results are presented. The DRM and orthophoto mosaics are generated showing no radiometric differences at the seam lines.

  10. The development and application of quantitative methods for the determination of in-situ radiometric uranium grade on the Witwatersrand gold and uranium mines

    International Nuclear Information System (INIS)

    Symons, G.

    1985-12-01

    A detailed investigation of background radiation levels near the reef zone in the uranium section of the Western Areas Mine was conducted using a collimated radiometric face scanner. This study demonstrated that these radiation levels can be high; 25% or more of the counts measured when sampling a reef face may originate from a background source, especially from uranium ore rubble on the footwall close to the reef face. A method using a 20mm frontal shield was devised to obtain an accurate background correction. Three calibration schemes, the Area method, the Gamlog method, and the Deconvolution method were implemented for the production of accurate in-situ radiometric uranium grades. This involved the construction of a step-response calibration pad at Pelindaba together with the establisment of appropriate software and underground radiometric sampling procedures. Radiometric grades generated by these calibration procedures from 60 channel sections were on average 10% below those procured from conventional chip sampling. A correlation between gold and uranium grades was also evident. Crushed rock samples were collected to investigate the thorium problem and are still undergoing analysis at the time of writing. Refinements in the design of the collimated face scanner are also described

  11. Characterization of the Sonoran desert as a radiometric calibration target for Earth observing sensors

    Science.gov (United States)

    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.

  12. Validation of a densimeter calibration procedure for a secondary calibration laboratory

    International Nuclear Information System (INIS)

    Alpizar Herrera, Juan Carlos

    2014-01-01

    A survey was conducted to quantify the need for calibration of a density measurement instrument at the research units at the Sede Rodrigo Facio of the Universidad de Costa Rica. A calibration procedure was documented for the instrument that presented the highest demand in the survey by the calibration service. A study of INTE-ISO/IEC 17025: 2005 and specifically in section 5.4 of this standard was done, to document the procedure for calibrating densimeters. Densimeter calibration procedures and standards were sought from different national and international sources. The method of hydrostatic weighing or Cuckow method was the basis of the defined procedure. Documenting the calibration procedure and creating other documents was performed for data acquisition log, intermediate calculation log and calibration certificate copy. A veracity test was performed using as reference laboratory a laboratory of calibration secondary national as part of the validation process of the documented procedure. The results of the E_n statistic of 0.41; 0.34 and 0.46 for the calibration points 90%, 50% and 10% were obtained for the densimeter scale respectively. A reproducibility analysis of the method was performed with satisfactory results. Different suppliers were contacted to estimate the economic costs of the equipment and materials, needed to develop the documented method of densimeter calibration. The acquisition of an analytical balance was recommended, instead of a precision scale, in order to improve the results obtained with the documented method [es

  13. Experiences with radiometric solid matter determination in the WOLPRYLA-65 fibre production

    International Nuclear Information System (INIS)

    Butz, M.; Traeber, K.

    1977-01-01

    Proceeding from the technology of WOLPRYLA-65 fibre fabrication the applicability of radiometric density measurements for acrylonitrile determination in a dimethylformamide bath has been studied. The measuring equipment and measuring positions are described and further details, such as calibration procedures, measuring accuracy, benefit of continuous and contactless measurements, maintenance efforts, and radiation protection measures are outlined

  14. PLEIADES-HR INNOVATIVE TECHNIQUES FOR RADIOMETRIC IMAGE QUALITY COMMISSIONING

    Directory of Open Access Journals (Sweden)

    G. Blanchet

    2012-07-01

    Full Text Available 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.

  15. Compact radiometric microwave calibrator

    International Nuclear Information System (INIS)

    Fixsen, D. J.; Wollack, E. J.; Kogut, A.; Limon, M.; Mirel, P.; Singal, J.; Fixsen, S. M.

    2006-01-01

    The calibration methods for the ARCADE II instrument are described and the accuracy estimated. The Steelcast coated aluminum cones which comprise the calibrator have a low reflection while maintaining 94% of the absorber volume within 5 mK of the base temperature (modeled). The calibrator demonstrates an absorber with the active part less than one wavelength thick and only marginally larger than the mouth of the largest horn and yet black (less than -40 dB or 0.01% reflection) over five octaves in frequency

  16. Calibration procedure of Hukseflux SR25 to Establish the Diffuse Reference for the Outdoor Broadband Radiometer Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Reda, Ibrahim M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Andreas, Afshin M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-01

    Accurate pyranometer calibrations, traceable to internationally recognized standards, are critical for solar irradiance measurements. One calibration method is the component summation method, where the pyranometers are calibrated outdoors under clear sky conditions, and the reference global solar irradiance is calculated as the sum of two reference components, the diffuse horizontal and subtended beam solar irradiances. The beam component is measured with pyrheliometers traceable to the World Radiometric Reference, while there is no internationally recognized reference for the diffuse component. In the absence of such a reference, we present a method to consistently calibrate pyranometers for measuring the diffuse component. The method is based on using a modified shade/unshade method and a pyranometer with less than 0.5 W/m2 thermal offset. The calibration result shows that the responsivity of Hukseflux SR25 pyranometer equals 10.98 uV/(W/m2) with +/-0.86 percent uncertainty.

  17. Method for radiometric calibration of an endoscope's camera and light source

    Science.gov (United States)

    Rai, Lav; Higgins, William E.

    2008-03-01

    An endoscope is a commonly used instrument for performing minimally invasive visual examination of the tissues inside the body. A physician uses the endoscopic video images to identify tissue abnormalities. The images, however, are highly dependent on the optical properties of the endoscope and its orientation and location with respect to the tissue structure. The analysis of endoscopic video images is, therefore, purely subjective. Studies suggest that the fusion of endoscopic video images (providing color and texture information) with virtual endoscopic views (providing structural information) can be useful for assessing various pathologies for several applications: (1) surgical simulation, training, and pedagogy; (2) the creation of a database for pathologies; and (3) the building of patient-specific models. Such fusion requires both geometric and radiometric alignment of endoscopic video images in the texture space. Inconsistent estimates of texture/color of the tissue surface result in seams when multiple endoscopic video images are combined together. This paper (1) identifies the endoscope-dependent variables to be calibrated for objective and consistent estimation of surface texture/color and (2) presents an integrated set of methods to measure them. Results show that the calibration method can be successfully used to estimate objective color/texture values for simple planar scenes, whereas uncalibrated endoscopes performed very poorly for the same tests.

  18. Monitoring of plutonium contaminated solid waste streams. Chapter II: principles and theory of radiometric assay

    International Nuclear Information System (INIS)

    Birkhoff, G.; Bondar, L.; Notea, A.; Segal, Y.

    1977-01-01

    The interpretation of a count rate distribution obtained from radiometric assay of a given waste items population in terms of source strength distribution is discussed. A model for the evaluation of errors, arising from non uniform source density distribution (Pu) within the item volume and heterogeneity of matrix materials, is presented. Points concerning calibration procedures and representativity of reference materials are dealt with. Qualification procedures for possible monitoring systems are outlined on the basis of comparison with reference systems. The latter are composed of reference monitors based on high resolution gamma spectrometry and passive and active neutron techniques. The importance of information upon the elemental composition and density distribution of matrix materials for the interpretation of radiometric assay of solid wastes is stressed

  19. Radiometric Cross-Calibration of the Chilean Satellite FASat-C Using RapidEye and EO-1 Hyperion Data and a Simultaneous Nadir Overpass Approach

    Directory of Open Access Journals (Sweden)

    Carolina Barrientos

    2016-07-01

    Full Text Available The absolute radiometric calibration of a satellite sensor is the critical factor that ensures the usefulness of the acquired data for quantitative applications on remote sensing. This work presents the results of the first cross-calibration of the sensor on board the Sistema Satelital de Observación de la Tierra (SSOT Chilean satellite or Air Force Satellite FASat-C. RapidEye-MSI was chosen as the reference sensor, and a simultaneous Nadir Overpass Approach (SNO was applied. The biases caused by differences in the spectral responses of both instruments were compensated through an adjustment factor derived from EO-1 Hyperion data. Through this method, the variations affecting the radiometric response of New AstroSat Optical Modular Instrument (NAOMI-1, have been corrected based on collections over the Frenchman Flat calibration site. The results of a preliminary evaluation of the pre-flight and updated coefficients have shown a significant improvement in the accuracy of at-sensor radiances and TOA reflectances: an average agreement of 2.63% (RMSE was achieved for the multispectral bands of both instruments. This research will provide a basis for the continuity of calibration and validation tasks of future Chilean space missions.

  20. PTB’s radiometric scales for UV and VUV source calibration based on synchrotron radiation

    Science.gov (United States)

    Klein, Roman; Kroth, Simone; Paustian, Wolfgang; Richter, Mathias; Thornagel, Reiner

    2018-06-01

    The radiant intensity of synchrotron radiation can be accurately calculated with classical electrodynamics. This primary realization of the spectral radiant intensity has been used by PTB at several electron storage rings which have been optimized to be operated as primary source standards for the calibration of transfer sources in the spectral range of UV and VUV for almost 30 years. The transfer sources are compared to the primary source standard by means of suitable wavelength-dispersive transfer stations. The spectral range covered by deuterium lamps, which represent transfer sources that are easy to handle, is of particular relevance in practice. Here, we report on developments in the realization and preservation of the radiometric scales for spectral radiant intensity and spectral radiance in the wavelength region from 116 nm to 400 nm, based on a set of deuterium reference lamps, over the last few decades. An inside view and recommendations on the operation of the D2 lamps used for the realization of the radiometric scale are presented. The data has been recently compiled to illustrate the chronological behaviour at various wavelengths. Moreover, an overview of the internal and external validation measurements and intercomparisons is given.

  1. The stars: an absolute radiometric reference for the on-orbit calibration of PLEIADES-HR satellites

    Science.gov (United States)

    Meygret, Aimé; Blanchet, Gwendoline; Mounier, Flore; Buil, Christian

    2017-09-01

    The accurate on-orbit radiometric calibration of optical sensors has become a challenge for space agencies who gather their effort through international working groups such as CEOS/WGCV or GSICS with the objective to insure the consistency of space measurements and to reach an absolute accuracy compatible with more and more demanding scientific needs. Different targets are traditionally used for calibration depending on the sensor or spacecraft specificities: from on-board calibration systems to ground targets, they all take advantage of our capacity to characterize and model them. But achieving the in-flight stability of a diffuser panel is always a challenge while the calibration over ground targets is often limited by their BDRF characterization and the atmosphere variability. Thanks to their agility, some satellites have the capability to view extra-terrestrial targets such as the moon or stars. The moon is widely used for calibration and its albedo is known through ROLO (RObotic Lunar Observatory) USGS model but with a poor absolute accuracy limiting its use to sensor drift monitoring or cross-calibration. Although the spectral irradiance of some stars is known with a very high accuracy, it was not really shown that they could provide an absolute reference for remote sensors calibration. This paper shows that high resolution optical sensors can be calibrated with a high absolute accuracy using stars. The agile-body PLEIADES 1A satellite is used for this demonstration. The star based calibration principle is described and the results are provided for different stars, each one being acquired several times. These results are compared to the official calibration provided by ground targets and the main error contributors are discussed.

  2. Wide Band and Wide Azimuth Beam Effect on High-resolution Synthetic Aperture Radar Radiometric Calibration

    Directory of Open Access Journals (Sweden)

    Hong Jun

    2015-06-01

    Full Text Available Passive corner reflectors and active transponders are often used as man-made reference targets in Synthetic Aperture Radar (SAR radiometric calibration, With the emergence of new radar systems and the increasing demand for greater accuracy, wide-band and wide-beam radars challenge the hypothesis that the Radar Cross Section (RCS of reference targets is constant. In this study, the FEKO electromagnetic simulation software is used to obtain the change curve of the target RCS as a function of frequency and aspect angle while incorporating high-resolution point-target SAR simulation, and quantitatively analyzing the effect of the modulation effect on SAR images. The simulation results suggest that the abovementioned factors affect the SAR calibration by more than 0.2 dB within a fractional bandwidth greater than 10% or azimuth beam width of more than 20°, which must be corrected in the data processing.

  3. Evaluation of relative radiometric correction techniques on Landsat 8 OLI sensor data

    Science.gov (United States)

    Novelli, Antonio; Caradonna, Grazia; Tarantino, Eufemia

    2016-08-01

    The quality of information derived from processed remotely sensed data may depend upon many factors, mostly related to the extent data acquisition is influenced by atmospheric conditions, topographic effects, sun angle and so on. The goal of radiometric corrections is to reduce such effects in order enhance the performance of change detection analysis. There are two approaches to radiometric correction: absolute and relative calibrations. Due to the large amount of free data products available, absolute radiometric calibration techniques may be time consuming and financially expensive because of the necessary inputs for absolute calibration models (often these data are not available and can be difficult to obtain). The relative approach to radiometric correction, known as relative radiometric normalization, is preferred with some research topics because no in situ ancillary data, at the time of satellite overpasses, are required. In this study we evaluated three well known relative radiometric correction techniques using two Landsat 8 - OLI scenes over a subset area of the Apulia Region (southern Italy): the IR-MAD (Iteratively Reweighted Multivariate Alteration Detection), the HM (Histogram Matching) and the DOS (Dark Object Subtraction). IR-MAD results were statistically assessed within a territory with an extremely heterogeneous landscape and all computations performed in a Matlab environment. The panchromatic and thermal bands were excluded from the comparisons.

  4. Radiometric diagnosis of Mycobacterium tuberculosis

    International Nuclear Information System (INIS)

    Laszlo, A.

    1986-01-01

    The results of this study confirm that rapid radiometric diagnostic tests such as the NAP selective inhibition test for the M. tuberculosis complex followed by the radiometric drug susceptibility tests are extremely reliable and compare favourably with conventional methodologies. This study also shows that referred cultures growing on solid medium can be processed by radiometric procedures without prior subculture. This circumstance by itself shortens the time needed for reporting. (Auth.)

  5. Effect of MODIS Terra Radiometric Calibration Improvements on Collection 6 Deep Blue Aerosol Products: Validation and Terra/Aqua Consistency

    Science.gov (United States)

    Sayer, A. M.; Hsu, N. C.; Bettenhausen, C.; Jeong, M.-J.; Meister, G.

    2015-01-01

    The Deep Blue (DB) algorithm's primary data product is midvisible aerosol optical depth (AOD). DB applied to Moderate Resolution Imaging Spectroradiometer (MODIS) measurements provides a data record since early 2000 for MODIS Terra and mid-2002 for MODIS Aqua. In the previous data version (Collection 5, C5), DB production from Terra was halted in 2007 due to sensor degradation; the new Collection 6 (C6) has both improved science algorithms and sensor radiometric calibration. This includes additional calibration corrections developed by the Ocean Biology Processing Group to address MODIS Terra's gain, polarization sensitivity, and detector response versus scan angle, meaning DB can now be applied to the whole Terra record. Through validation with Aerosol Robotic Network (AERONET) data, it is shown that the C6 DB Terra AOD quality is stable throughout the mission to date. Compared to the C5 calibration, in recent years the RMS error compared to AERONET is smaller by approximately 0.04 over bright (e.g., desert) and approximately 0.01-0.02 over darker (e.g., vegetated) land surfaces, and the fraction of points in agreement with AERONET within expected retrieval uncertainty higher by approximately 10% and approximately 5%, respectively. Comparisons to the Aqua C6 time series reveal a high level of correspondence between the two MODIS DB data records, with a small positive (Terra-Aqua) average AOD offset <0.01. The analysis demonstrates both the efficacy of the new radiometric calibration efforts and that the C6 MODIS Terra DB AOD data remain stable (to better than 0.01 AOD) throughout the mission to date, suitable for quantitative scientific analyses.

  6. Process system of radiometric and magnetometric aerial information

    International Nuclear Information System (INIS)

    Bazua Rueda, L.F.

    1985-01-01

    The author has been working first in the National Institute of Nuclear Energy (Mexico) and then in URAMEX (Uranio Mexicano) since 1975 to 1983, integrated to radiometric and magnetometric aerial prospecting projects in computerized processing of information aspects. During this period the author participated in the work out of computing systems, information processing and mathematical procedures definition for the geophysical reduction of the calibration equipment data. With cumulated experience, in this thesis are presented aspects concerning to management and operation of computerized processing of information systems. Operation handbooks of the majority of modules are presented. Program lists are not included. (Author)

  7. Optimization of procedure for calibration with radiometer/photometer

    International Nuclear Information System (INIS)

    Detilly, Isabelle

    2009-01-01

    A test procedure for the radiometer/photometer calibrations mark International Light at the Laboratorio de Fotometria y Tecnologia Laser (LAFTA) de la Escuela de Ingenieria Electrica de la Universidad de Costa Rica is established. Two photometric banks are used as experimental set and two calibrations were performed of the International Light. A basic procedure established in the laboratory, is used for calibration from measurements of illuminance and luminous intensity. Some dependent variations of photometric banks used in the calibration process, the programming of the radiometer/photometer and the applied methodology showed the results. The procedure for calibration with radiometer/photometer can be improved by optimizing the programming process of the measurement instrument and possible errors can be minimized by using the recommended procedure. (author) [es

  8. The Impact of Indoor and Outdoor Radiometer Calibration on Solar Measurements: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Habte, Aron; Sengupta, Manajit; Andreas, Afshin; Reda, Ibrahim; Robinson, Justin

    2016-07-01

    Accurate solar radiation data sets are critical to reducing the expenses associated with mitigating performance risk for solar energy conversion systems, and they help utility planners and grid system operators understand the impacts of solar resource variability. The accuracy of solar radiation measured by radiometers depends on the instrument performance specification, installation method, calibration procedure, measurement conditions, maintenance practices, location, and environmental conditions. This study addresses the effect of calibration methodologies and the resulting calibration responsivities provided by radiometric calibration service providers such as the National Renewable Energy Laboratory (NREL) and manufacturers of radiometers. Some of these radiometers are calibrated indoors, and some are calibrated outdoors. To establish or understand the differences in calibration methodology, we processed and analyzed field-measured data from these radiometers. This study investigates calibration responsivities provided by NREL's broadband outdoor radiometer calibration (BORCAL) and a few prominent manufacturers. The reference radiometer calibrations are traceable to the World Radiometric Reference. These different methods of calibration demonstrated 1% to 2% differences in solar irradiance measurement. Analyzing these values will ultimately assist in determining the uncertainties of the radiometer data and will assist in developing consensus on a standard for calibration.

  9. Radiometric analyzer

    International Nuclear Information System (INIS)

    Arima, S.; Oda, M.; Miyashita, K.; Takada, M.

    1977-01-01

    A radiometric analyzer for measuring the characteristic values of a sample by radiation includes a humer of radiation measuring subsystems having different ratios of sensitivities to the elements of the sample and linearizing circuits having inverse function characteristics of calibration functions which correspond to the radiation measuring subsystems. A weighing adder operates a desirable linear combination of the outputs of the linearizing circuits. Operators for operating between two or more different linear combinations are included

  10. Calibration and Measurement Uncertainty Estimation of Radiometric Data: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Habte, A.; Sengupta, M.; Reda, I.; Andreas, A.; Konings, J.

    2014-11-01

    Evaluating the performance of photovoltaic cells, modules, and arrays that form large solar deployments relies on accurate measurements of the available solar resource. Therefore, determining the accuracy of these solar radiation measurements provides a better understanding of investment risks. This paper provides guidelines and recommended procedures for estimating the uncertainty in calibrations and measurements by radiometers using methods that follow the International Bureau of Weights and Measures Guide to the Expression of Uncertainty (GUM). Standardized analysis based on these procedures ensures that the uncertainty quoted is well documented.

  11. THE EUROSDR PROJECT "RADIOMETRIC ASPECTS OF DIGITAL PHOTOGRAMMETRIC IMAGES" – RESULTS OF THE EMPIRICAL PHASE

    Directory of Open Access Journals (Sweden)

    E. Honkavaara

    2012-09-01

    Full Text Available 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.

  12. The construction of a radiometric calibration facility at Lanseria Airport, Republic of South Africa

    International Nuclear Information System (INIS)

    Corner, B.; Smit, C.J.B.

    1983-08-01

    The construction of standard sources suitable for the calibration of airborne and truck-mounted gamma-spectrometer systems is described. Four sources were built, three of which were doped with preselected quantities of uranium, thorium or potassium. A fourth source was left barren so as to provide a measure of the background radiation in the area. The sources are 8 m in diameter, 0,35 m thick and are recessed into the disused northern portion of runway 17 at Lanseria Airport, north of Johannesburg. Adopted concentrations of the major radioelements in the sources are: 6,10 % k 2 O in the potasssium source, 67,0 ppm U 3 O 8 in the uranium source (radiometric), 158 ppm ThO 2 in the thorium source

  13. Advanced Calibration Source for Planetary and Earth Observing Imaging

    Data.gov (United States)

    National Aeronautics and Space Administration — Planetary and Earth imaging requires radiometrically calibrated and stable imaging sensors.  Radiometric calibration enables the ability to remove or mitigate...

  14. MER 1 MARS NAVCAM 3 RADIOMETRIC RDR SCI V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains radiometrically calibrated MER-1 Navcam data. The calibration has removed bias, dark current, and flatfield effects from the raw Navcam data,...

  15. ASD FieldSpec Calibration Setup and Techniques

    Science.gov (United States)

    Olive, Dan

    2001-01-01

    This paper describes the Analytical Spectral Devices (ASD) Fieldspec Calibration Setup and Techniques. The topics include: 1) ASD Fieldspec FR Spectroradiometer; 2) Components of Calibration; 3) Equipment list; 4) Spectral Setup; 5) Spectral Calibration; 6) Radiometric and Linearity Setup; 7) Radiometric setup; 8) Datadets Required; 9) Data files; and 10) Field of View Measurement. This paper is in viewgraph form.

  16. Research on orbit prediction for solar-based calibration proper satellite

    Science.gov (United States)

    Chen, Xuan; Qi, Wenwen; Xu, Peng

    2018-03-01

    Utilizing the mathematical model of the orbit mechanics, the orbit prediction is to forecast the space target's orbit information of a certain time based on the orbit of the initial moment. The proper satellite radiometric calibration and calibration orbit prediction process are introduced briefly. On the basis of the research of the calibration space position design method and the radiative transfer model, an orbit prediction method for proper satellite radiometric calibration is proposed to select the appropriate calibration arc for the remote sensor and to predict the orbit information of the proper satellite and the remote sensor. By analyzing the orbit constraint of the proper satellite calibration, the GF-1solar synchronous orbit is chose as the proper satellite orbit in order to simulate the calibration visible durance for different satellites to be calibrated. The results of simulation and analysis provide the basis for the improvement of the radiometric calibration accuracy of the satellite remote sensor, which lays the foundation for the high precision and high frequency radiometric calibration.

  17. The absolute calibration of KOMPSAT-3 and 3A high spatial resolution satellites using radiometric tarps and MFRSR measurments

    Science.gov (United States)

    Yeom, J. M.

    2017-12-01

    Recently developed Korea Multi-Purpose Satellite-3A (KOMPSAT-3A), which is a continuation of the KOMPSAT-1, 2 and 3 earth observation satellite (EOS) programs from the Korea Aerospace Research Institute (KARI) was launched on March, 25 2015 on a Dnepr-1 launch vehicle from the Jasny Dombarovsky site in Russia. After launched, KARI performed in-orbit-test (IOT) including radiometric calibration for 6 months from 14 Apr. to 4 Sep. 2015. KOMPSAT-3A is equipped with two distinctive sensors; one is a high resolution multispectral optical sensor, namely the Advances Earth Image Sensor System-A (AEISS-A) and the other is the Scanner Infrared Imaging System (SIIS). In this study, we focused on the radiometric calibration of AEISS-A. The multispectral wavelengths of AEISS-A are covering three visible regions: blue (450 - 520 nm), green (520 - 600 nm), red (630 - 690 nm), one near infrared (760 - 900 nm) with a 2.0 m spatial resolution at nadir, whereas the panchromatic imagery (450 - 900 nm) has a 0.5 m resolution. Those are the same spectral response functions were same with KOMPSAT-3 multispectral and panchromatic bands but the spatial resolutions are improved. The main mission of KOMPSAT-3A is to develop for Geographical Information System (GIS) applications in environmental, agriculture, and oceanographic sciences, as well as natural hazard monitoring.

  18. Radiometric analyzer with plural radiation sources and detectors

    International Nuclear Information System (INIS)

    Arima, S.; Oda, M.; Miyashita, K.; Takada, M.

    1977-01-01

    A radiometric analyzer for measuring characteristics of a material by radiation comprises a plurality of systems in which each consists of a radiation source and a radiation detector which are the same in number as the number of elements of the molecule of the material and a linear calibration circuit having inverse response characteristics (calibration curve) of the respective systems of detectors, whereby the measurement is carried out by four fundamental rules by operation of the mutual outputs of said detector system obtained through said linear calibration circuit. One typical embodiment is a radiometric analyzer for hydrocarbons which measures the density of heavy oil, the sulfur content and the calorific value by three detector systems which include a γ-ray source (E/sub γ/ greater than 50 keV), a soft x-ray source (Ex approximately 20 keV), and a neutron ray source. 2 claims, 6 figures

  19. Radiometric inter-sensor cross-calibration uncertainty using a traceable high accuracy reference hyperspectral imager

    Science.gov (United States)

    Gorroño, Javier; Banks, Andrew C.; Fox, Nigel P.; Underwood, Craig

    2017-08-01

    Optical earth observation (EO) satellite sensors generally suffer from drifts and biases relative to their pre-launch calibration, caused by launch and/or time in the space environment. This places a severe limitation on the fundamental reliability and accuracy that can be assigned to satellite derived information, and is particularly critical for long time base studies for climate change and enabling interoperability and Analysis Ready Data. The proposed TRUTHS (Traceable Radiometry Underpinning Terrestrial and Helio-Studies) mission is explicitly designed to address this issue through re-calibrating itself directly to a primary standard of the international system of units (SI) in-orbit and then through the extension of this SI-traceability to other sensors through in-flight cross-calibration using a selection of Committee on Earth Observation Satellites (CEOS) recommended test sites. Where the characteristics of the sensor under test allows, this will result in a significant improvement in accuracy. This paper describes a set of tools, algorithms and methodologies that have been developed and used in order to estimate the radiometric uncertainty achievable for an indicative target sensor through in-flight cross-calibration using a well-calibrated hyperspectral SI-traceable reference sensor with observational characteristics such as TRUTHS. In this study, Multi-Spectral Imager (MSI) of Sentinel-2 and Landsat-8 Operational Land Imager (OLI) is evaluated as an example, however the analysis is readily translatable to larger-footprint sensors such as Sentinel-3 Ocean and Land Colour Instrument (OLCI) and Visible Infrared Imaging Radiometer Suite (VIIRS). This study considers the criticality of the instrumental and observational characteristics on pixel level reflectance factors, within a defined spatial region of interest (ROI) within the target site. It quantifies the main uncertainty contributors in the spectral, spatial, and temporal domains. The resultant tool

  20. Improvement of gamma calibration procedures with commercial management software

    International Nuclear Information System (INIS)

    Lucena, Rodrigo F.; Potiens, Maria da Penha A.; Santos, Gelson P.; Vivolo, Vitor

    2007-01-01

    In this work, the gamma calibration procedure of the Instruments Calibration Laboratory (LCI) of the IPEN-CNEN-SP was improved with the use of the commercial management software Autolab TM from Automa Company. That software was adapted for our specific use in the calibration procedures. The evaluation of the uncertainties in gamma calibration protocol was improved by the LCI staff and yet the all worksheets and final calibration report lay-out was developed in commercial software like Excell TM and Word TM from Microsft TM . (author)

  1. Laboratory-based bidirectional reflectance distribution functions of radiometric tarps

    International Nuclear Information System (INIS)

    Georgiev, Georgi T.; Butler, James J.

    2008-01-01

    Laboratory-based bidirectional reflectance distribution functions (BRDFs) of radiometric tarp samples used in the vicarious calibration of Earth remote sensing satellite instruments are presented in this paper. The results illustrate the BRDF dependence on the orientation of the tarps' weft and warp threads. The study was performed using the GSFC scatterometer at incident zenith angles of 0 deg., 10 deg., and 30 deg.; scatter zenith angles from 0 deg. to 60 deg.; and scatter azimuth angles of 0 deg., 45 deg., 90 deg., 135 deg., and 180 deg.. The wavelengths were 485 nm, 550 nm, 633 nm, and 800 nm. The tarp's weft and warp dependence on BRDF is well defined at all measurement geometries and wavelengths. The BRDF difference can be as high as 8% at 0 deg. incident angle and 12% at 30 deg. 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 are reported. The backward scatter is well pronounced for the white samples. The black sample has well-pronounced forward scatter. The provided BRDF characterization of radiometric tarps is an excellent reference for anyone interested in using tarps for radiometric calibrations. The results are NIST traceable

  2. Laboratory-based bidirectional reflectance distribution functions of radiometric tarps.

    Science.gov (United States)

    Georgiev, Georgi T; Butler, James J

    2008-06-20

    Laboratory-based bidirectional reflectance distribution functions (BRDFs) of radiometric tarp samples used in the vicarious calibration of Earth remote sensing satellite instruments are presented in this paper. The results illustrate the BRDF dependence on the orientation of the tarps' weft and warp threads. The study was performed using the GSFC scatterometer at incident zenith angles of 0 degrees, 10 degrees, and 30 degrees; scatter zenith angles from 0 degrees to 60 degrees; and scatter azimuth angles of 0 degrees, 45 degrees, 90 degrees, 135 degrees, and 180 degrees. The wavelengths were 485 nm, 550 nm, 633 nm, and 800 nm. The tarp's weft and warp dependence on BRDF is well defined at all measurement geometries and wavelengths. The BRDF difference can be as high as 8% at 0 degrees incident angle and 12% at 30 degrees 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 are reported. The backward scatter is well pronounced for the white samples. The black sample has well-pronounced forward scatter. The provided BRDF characterization of radiometric tarps is an excellent reference for anyone interested in using tarps for radiometric calibrations. The results are NIST traceable.

  3. The Calibration Home Base for Imaging Spectrometers

    Directory of Open Access Journals (Sweden)

    Johannes Felix Simon Brachmann

    2016-08-01

    Full Text Available The Calibration Home Base (CHB is an optical laboratory designed for the calibration of imaging spectrometers for the VNIR/SWIR wavelength range. Radiometric, spectral and geometric calibration as well as the characterization of sensor signal dependency on polarization are realized in a precise and highly automated fashion. This allows to carry out a wide range of time consuming measurements in an ecient way. The implementation of ISO 9001 standards in all procedures ensures a traceable quality of results. Spectral measurements in the wavelength range 380–1000 nm are performed to a wavelength uncertainty of +- 0.1 nm, while an uncertainty of +-0.2 nm is reached in the wavelength range 1000 – 2500 nm. Geometric measurements are performed at increments of 1.7 µrad across track and 7.6 µrad along track. Radiometric measurements reach an absolute uncertainty of +-3% (k=1. Sensor artifacts, such as caused by stray light will be characterizable and correctable in the near future. For now, the CHB is suitable for the characterization of pushbroom sensors, spectrometers and cameras. However, it is planned to extend the CHBs capabilities in the near future such that snapshot hyperspectral imagers can be characterized as well. The calibration services of the CHB are open to third party customers from research institutes as well as industry.

  4. Effects of Landsat 5 Thematic Mapper and Landsat 7 Enhanced Thematic Mapper plus radiometric and geometric calibrations and corrections on landscape characterization

    Science.gov (United States)

    Vogelmann, James E.; Helder, Dennis; Morfitt, Ron; Choate, Michael J.; Merchant, James W.; Bulley, Henry

    2001-01-01

    The Thematic Mapper (TM) instruments onboard Landsats 4 and 5 provide high-quality imagery appropriate for many different applications, including land cover mapping, landscape ecology, and change detection. Precise calibration was considered to be critical to the success of the Landsat 7 mission and, thus, issues of calibration were given high priority during the development of the Enhanced Thematic Mapper Plus (ETM+). Data sets from the Landsat 5 TM are not routinely corrected for a number of radiometric and geometric artifacts, including memory effect, gain/bias, and interfocal plane misalignment. In the current investigation, the effects of correcting vs. not correcting these factors were investigated for several applications. Gain/bias calibrations were found to have a greater impact on most applications than did memory effect calibrations. Correcting interfocal plane offsets was found to have a moderate effect on applications. On June 2, 1999, Landsats 5 and 7 data were acquired nearly simultaneously over a study site in the Niobrara, NE area. Field radiometer data acquired at that site were used to facilitate crosscalibrations of Landsats 5 and 7 data. Current findings and results from previous investigations indicate that the internal calibrator of Landsat 5 TM tracked instrument gain well until 1988. After this, the internal calibrator diverged from the data derived from vicarious calibrations. Results from this study also indicate very good agreement between prelaunch measurements and vicarious calibration data for all Landsat 7 reflective bands except Band 4. Values are within about 3.5% of each other, except for Band 4, which differs by 10%. Coefficient of variation (CV) values derived from selected targets in the imagery were also analyzed. The Niobrara Landsat 7 imagery was found to have lower CV values than Landsat 5 data, implying that lower levels of noise characterize Landsat 7 data than current Landsat 5 data. It was also found that following

  5. Empirical Radiometric Normalization of Road Points from Terrestrial Mobile Lidar System

    Directory of Open Access Journals (Sweden)

    Tee-Ann Teo

    2015-05-01

    Full Text Available Lidar data provide both geometric and radiometric information. Radiometric information is influenced by sensor and target factors and should be calibrated to obtain consistent energy responses. The radiometric correction of airborne lidar system (ALS converts the amplitude into a backscatter cross-section with physical meaning value by applying a model-driven approach. The radiometric correction of terrestrial mobile lidar system (MLS is a challenging task because it does not completely follow the inverse square range function at near-range. This study proposed a radiometric normalization workflow for MLS using a data-driven approach. The scope of this study is to normalize amplitude of road points for road surface classification, assuming that road points from different scanners or strips should have similar responses in overlapped areas. The normalization parameters for range effect were obtained from crossroads. The experiment showed that the amplitude difference between scanners and strips decreased after radiometric normalization and improved the accuracy of road surface classification.

  6. Initial Radiometric Characteristics of KOMPSAT-3A Multispectral Imagery Using the 6S Radiative Transfer Model, Well-Known Radiometric Tarps, and MFRSR Measurements

    Directory of Open Access Journals (Sweden)

    Jong-Min Yeom

    2017-02-01

    Full Text Available On-orbit radiometric characterization of the multispectral (MS imagery of the Korea Aerospace Research Institute (KARI’s Korea Multi-Purpose Satellite-3A (KOMPSAT-3A, which was launched on 25 March 2015, was conducted to provide quantitative radiometric information about KOMPSAT-3A. During the in-orbit test (IOT, vicarious radiometric calibration of KOMPSAT-3A was performed using the Second Simulation of a Satellite Signal in the Solar Spectrum (6S radiative transfer model. The characteristics of radiometric tarps, the atmospheric optical depth from multi-filter rotating shadowband radiometer (MFRSR measurements, and sun–sensor–geometry were carefully considered, in order to calculate the exact top of atmosphere (TOA radiance received by KOMPSAT-3A MS bands. In addition, the bidirectional reflectance distribution function (BRDF behaviors of the radiometric tarps were measured in the laboratory with a two-dimensional hyperspectral gonioradiometer, to compensate for the geometry discrepancy between the satellite and the ASD FieldSpec® 3 spectroradiometer. The match-up datasets between the TOA radiance and the digital number (DN from KOMPSAT-3A were used to determine DN-to-radiance conversion factors, based on linear least squares fitting for two field campaigns. The final results showed that the R2 values between the observed and simulated radiances for the blue, green, red, and near-infrared (NIR bands, are greater than 0.998. An approximate error budget analysis for the vicarious calibration of KOMPSAT-3A showed an error of less than 6.8%. When applying the laboratory-based BRDF correction to the case of higher viewing zenith angle geometry, the gain ratio was improved, particularly for the blue (1.3% and green (1.2% bands, which exhibit high sensitivity to the BRDF of radiometric tarps during the backward-scattering phase. The calculated gain ratio between the first and second campaigns showed a less than 5% discrepancy, indicating that

  7. Airborne radiometric: Data evaluation and calibration

    International Nuclear Information System (INIS)

    Wendt, I.; Sengpiel, K.P.; Lenz, H.

    1984-01-01

    The airborne geophysical system of the BGR (German Geological Survey) consists of a helicopter equipped with an electromagnetic system with two transmittors and two receivers, a proton resonance magnetometer and a 16 L NaJ-crystal with four channel recording. All these data together with navigation data and flight altitude above ground are recorded each second on a nine track magnetic tape for further data evaluation. Different corrections have to be applied to the rough data such as: smoothing by means of a digital filter to reduce statistical noise, altitude correction, Compton-correction, and drift correction (cross-profile evaluation). Then the corrected measuring data are combined with the navigation data in order to be able to produce iso-line maps. The final results are presented as: line plots for U, Th, and K (and EM-data and magnetometer data); actual flight line plots; iso-line maps for U, Th, and K; iso-line maps for conductivity; depth of conducting layer; and magnetometry maps. The procedures of correction and evaluation of the above mentioned data as well as the calibration of the NaJ-detector in terms of ppm U, Th, and %K are dicussed in the paper. (author)

  8. Results from the radiometric validation of Sentinel-3 optical sensors using natural targets

    Science.gov (United States)

    Fougnie, Bertrand; Desjardins, Camille; Besson, Bruno; Bruniquel, Véronique; Meskini, Naceur; Nieke, Jens; Bouvet, Marc

    2016-09-01

    The recently launched SENTINEL-3 mission measures sea surface topography, sea/land surface temperature, and ocean/land surface colour with high accuracy. The mission provides data continuity with the ENVISAT mission through acquisitions by multiple sensing instruments. Two of them, OLCI (Ocean and Land Colour Imager) and SLSTR (Sea and Land Surface Temperature Radiometer) are optical sensors designed to provide continuity with Envisat's MERIS and AATSR instruments. During the commissioning, in-orbit calibration and validation activities are conducted. Instruments are in-flight calibrated and characterized primarily using on-board devices which include diffusers and black body. Afterward, vicarious calibration methods are used in order to validate the OLCI and SLSTR radiometry for the reflective bands. The calibration can be checked over dedicated natural targets such as Rayleigh scattering, sunglint, desert sites, Antarctica, and tentatively deep convective clouds. Tools have been developed and/or adapted (S3ETRAC, MUSCLE) to extract and process Sentinel-3 data. Based on these matchups, it is possible to provide an accurate checking of many radiometric aspects such as the absolute and interband calibrations, the trending correction, the calibration consistency within the field-of-view, and more generally this will provide an evaluation of the radiometric consistency for various type of targets. Another important aspect will be the checking of cross-calibration between many other instruments such as MERIS and AATSR (bridge between ENVISAT and Sentinel-3), MODIS (bridge to the GSICS radiometric standard), as well as Sentinel-2 (bridge between Sentinel missions). The early results, based on the available OLCI and SLSTR data, will be presented and discussed.

  9. Procedures for calibration of brachytherapy sources

    International Nuclear Information System (INIS)

    Alfonso Laguardia, R.; Alonso Samper, J.L.; Morales Lopez, J.L.; Saez Nunez, D.G.

    1997-01-01

    Brachytherapy source strength verification is a responsibility of the user of these source, in fact of the Medical Physicists in charge of this issue in a Radiotherapy Service. The calibration procedures in the users conditions are shown. Specifics methods for source strength determination are recommended, both for High Dose Rate (HDR) sources with Remote Afterloading equipment and for Low Dose Rate sources. The The results of the calibration of HDR Remote After loaders are indicated

  10. Radiometric Cross-Calibration of GAOFEN-1 Wfv Cameras with LANDSAT-8 Oli and Modis Sensors Based on Radiation and Geometry Matching

    Science.gov (United States)

    Li, J.; Wu, Z.; Wei, X.; Zhang, Y.; Feng, F.; Guo, F.

    2018-04-01

    Cross-calibration has the advantages of high precision, low resource requirements and simple implementation. It has been widely used in recent years. The four wide-field-of-view (WFV) cameras on-board Gaofen-1 satellite provide high spatial resolution and wide combined coverage (4 × 200 km) without onboard calibration. In this paper, the four-band radiometric cross-calibration coefficients of WFV1 camera were obtained based on radiation and geometry matching taking Landsat 8 OLI (Operational Land Imager) sensor as reference. Scale Invariant Feature Transform (SIFT) feature detection method and distance and included angle weighting method were introduced to correct misregistration of WFV-OLI image pair. The radiative transfer model was used to eliminate difference between OLI sensor and WFV1 camera through the spectral match factor (SMF). The near-infrared band of WFV1 camera encompasses water vapor absorption bands, thus a Look Up Table (LUT) for SMF varies from water vapor amount is established to estimate the water vapor effects. The surface synchronization experiment was designed to verify the reliability of the cross-calibration coefficients, which seem to perform better than the official coefficients claimed by the China Centre for Resources Satellite Data and Application (CCRSDA).

  11. Instrument Calibration and Certification Procedure

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R. Wesley [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-05-31

    The Amptec 640SL-2 is a 4-wire Kelvin failsafe resistance meter, designed to reliably use very low-test currents for its resistance measurements. The 640SL-1 is a 2-wire version, designed to support customers using the Reynolds Industries type 311 connector. For both versions, a passive (analog) dual function DC Milliameter/Voltmeter allows the user to verify the actual 640SL output current level and the open circuit voltage on the test leads. This procedure includes tests of essential performance parameters. Any malfunction noticed during calibration, whether specifically tested for or not, shall be corrected before calibration continues or is completed.

  12. Primary calibrations of radionuclide solutions and sources for the EML quality assessment program

    Energy Technology Data Exchange (ETDEWEB)

    Fisenne, I.M. [Dept. of Energy, New York, NY (United States)

    1993-12-31

    The quality assurance procedures established for the operation of the U.S. Department of Energy`s Environmental Measurements Laboratory (DOE-EML`s) Quality Assessment Program (QAP) are essentially the same as those that are in effect for any EML program involving radiometric measurements. All these programs have at their core the use of radionuclide standards for their instrument calibration. This paper focuses on EML`s approach to the acquisition, calibration and application of a wide range of radionuclide sources that are required to meet its programmatic needs.

  13. LANL MTI calibration team experience

    Science.gov (United States)

    Bender, Steven C.; Atkins, William H.; Clodius, William B.; Little, Cynthia K.; Christensen, R. Wynn

    2004-01-01

    The Multispectral Thermal Imager (MTI) was designed as an imaging radiometer with absolute calibration requirements established by Department of Energy (DOE) mission goals. Particular emphasis was given to water surface temperature retrieval using two mid wave and three long wave infrared spectral bands, the fundamental requirement was a surface temperature determination of 1K at the 68% confidence level. For the ten solar reflective bands a one-sigma radiometric performance goal of 3% was established. In order to address these technical challenges a calibration facility was constructed containing newly designed sources that were calibrated at NIST. Additionally, the design of the payload and its onboard calibration system supported post launch maintenance and update of the ground calibration. The on-orbit calibration philosophy also included vicarious techniques using ocean buoys, playas and other instrumented sites; these became increasingly important subsequent to an electrical failure which disabled the onboard calibration system. This paper offers various relevant lessons learned in the eight-year process of reducing to practice the calibration capability required by the scientific mission. The discussion presented will include observations pertinent to operational and procedural issues as well as hardware experiences; the validity of some of the initial assumptions will also be explored.

  14. Radiometric survey in mammography: problems and challenges; Levantamento radiometrico em mamografia: problemas e desafios

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, M.V.T.; Navarro, V.C.C.; Garcia, I.F.M.; Ferreira, M.J.; Macedo, E.M., E-mail: navarro@ifba.edu.br [Instituto Federal da Bahia (LABPROSAUD/IFBA), Salvador, BA (Brazil). Laboratorio de Produtos para a Saude

    2015-07-01

    In addition to being mandatory, the radiometric survey is a necessity, especially in the Brazilian reality with the construction of smaller and smaller rooms. However, calibration conditions, the instrumentation and its use, can produce underestimated factors. Measures made at Labprosaud/IFBA, with five different instruments and the ISO N 25 radiation quality, show the possibility of the values presented in the radiometric surveys are underestimated by up to 10 times. The results indicate the need for meters to be calibrated in ISO N qualities, in mammography energy range, in integrated dose mode and exposure times shorter or equal to 1 s. (author)

  15. Broadband radiometric LED measurements

    Science.gov (United States)

    Eppeldauer, G. P.; Cooksey, C. C.; Yoon, H. W.; Hanssen, L. M.; Podobedov, V. B.; Vest, R. E.; Arp, U.; Miller, C. C.

    2016-09-01

    At present, broadband radiometric LED measurements with uniform and low-uncertainty results are not available. Currently, either complicated and expensive spectral radiometric measurements or broadband photometric LED measurements are used. The broadband photometric measurements are based on the CIE standardized V(λ) function, which cannot be used in the UV range and leads to large errors when blue or red LEDs are measured in its wings, where the realization is always poor. Reference irradiance meters with spectrally constant response and high-intensity LED irradiance sources were developed here to implement the previously suggested broadband radiometric LED measurement procedure [1, 2]. Using a detector with spectrally constant response, the broadband radiometric quantities of any LEDs or LED groups can be simply measured with low uncertainty without using any source standard. The spectral flatness of filtered-Si detectors and low-noise pyroelectric radiometers are compared. Examples are given for integrated irradiance measurement of UV and blue LED sources using the here introduced reference (standard) pyroelectric irradiance meters. For validation, the broadband measured integrated irradiance of several LED-365 sources were compared with the spectrally determined integrated irradiance derived from an FEL spectral irradiance lamp-standard. Integrated responsivity transfer from the reference irradiance meter to transfer standard and field UV irradiance meters is discussed.

  16. Urease testing of mycobacteria with BACTEC radiometric instrumentation

    International Nuclear Information System (INIS)

    Damato, J.J.; Collins, M.T.; McClatchy, J.K.

    1982-01-01

    A total of 140 mycobacterial isolates from patients treated at Fitzsimons Army Medical Center or the National Jewish Hospital and Research Center and from animal specimens submitted to the National Veterinary Services Laboratory were tested by using a urease procedure modified for use with a BACTEC model 301. Mycobacterial suspensions were prepared by using Middlebrook 7H10 Tween broth. Of the 98 mycobacteria isolates which were urease positive utilizing standard methodology, all were positive using the radiometric procedures. Similarly, all 42 urease-negative isolates were also negative employing the new methodology. Although maximum radiometric readings were observed at 48 h, all positive strains were readily identified 24 h after inoculation without sacrificing either test sensitivity or specificity. Thus, urease testing of mycobacteria, using the modified BACTEC radiometric methodology, was as sensitive, as specific, and more rapid than conventional methods

  17. Calibration Lessons Learned from Hyperion Experience

    Science.gov (United States)

    Casement, S.; Ho, K.; Sandor-Leahy, S.; Biggar, S.; Czapla-Myers, J.; McCorkel, J.; Thome, K.

    2009-12-01

    The use of hyperspectral imagers to provide climate-quality data sets, such as those expected from the solar reflective sensor on the Climate Absolute Radiance and Refractivity Observatory (CLARREO), requires stringent radiometric calibration requirements. These stringent requirements have been nearly met with broadband radiometers such as CERES, but high resolution spectrometers pose additional challenges. A review of the calibration processes for past space-based HSIs provide guidance on the calibration processes that will be needed for future sensors. In November 2000, the Earth Observer-1 (EO-1) platform was launched onboard a Boeing Delta II launch vehicle. The primary purpose of the EO-1 mission was to provide a technological testbed for spaceborne components. The platform has three sensors onboard, of which, the hyperspectral imager (HSI) Hyperion, is discussed here. The Hyperion sensor at the time had no comparable sensor in earth orbit, being the first grating-based, hyperspectral, civilian sensor in earth orbit. Ground and on-orbit calibration procedures including all cross-calibration activities have achieved an estimated instrument absolute radiometric error of 2.9% in the Visible channel (0.4 - 1.0 microns) and 3.4% in the shortwave infrared (SWIR, 0.9 - 2.5 microns) channel (EO-1/Hyperion Early Orbit Checkout Report Part II On-Orbit Performance Verification and Calibration). This paper describes the key components of the Hyperion calibration process that are applicable to future HSI missions. The pre-launch methods relied on then newly-developed, detector-based methods. Subsequent vicarious methods including cross-calibration with other sensors and the reflectance-based method showed significant differences from the prelaunch calibration. Such a difference demonstrated the importance of the vicarious methods as well as pointing to areas for improvement in the prelaunch methods. We also identify areas where lessons learned from Hyperion regarding

  18. Assessing Radiometric Stability of the 17-Plus-Year TRMM Microwave Imager 1B11 Version-8 (GPM05 Brightness Temperature Product

    Directory of Open Access Journals (Sweden)

    Ruiyao Chen

    2017-12-01

    Full Text Available The NASA Tropical Rainfall Measuring Mission (TRMM Microwave Imager (TMI has produced a 17-plus-year time-series of calibrated microwave radiances that have remarkable value for investigating the effects of the Earth’s climate change over the tropics. Recently, the Global Precipitation Measurement (GPM Inter-Satellite Radiometric Calibration (XCAL Working Group have performed various calibration and corrections that yielded the legacy TMI 1B11 Version 8 (also called GPM05 brightness temperature product, which will be released in late 2017 by the NASA Precipitation Processing System. Since TMI served as the radiometric transfer standard for the TRMM constellation microwave radiometer sensors, it is important to document its accuracy. In this paper, the various improvements applied to TMI 1B11 V8 are summarized, and the radiometric calibration stability is evaluated by comparisons with a radiative transfer model and by XCAL evaluations with the Global Precipitation Measuring Microwave Imager during their 13-month overlap period. Evaluation methods will be described and results will be presented, which demonstrate that TMI has achieved a radiometric stability level of a few deciKelvin over almost two decades.

  19. Statistical design of mass spectrometry calibration procedures

    International Nuclear Information System (INIS)

    Bayne, C.K.

    1996-11-01

    The main objective of this task was to agree on calibration procedures to estimate the system parameters (i.e., dead-time correction, ion-counting conversion efficiency, and detector efficiency factors) for SAL's new Finnigan MAT-262 mass spectrometer. SAL will use this mass spectrometer in a clean-laboratory which was opened in December 1995 to measure uranium and plutonium isotopes on environmental samples. The Finnigan MAT-262 mass spectrometer has a multi-detector system with seven Faraday cup detectors and one ion- counter for the measurement of very small signals (e.g. 10 -17 Ampere range). ORNL has made preliminary estimates of the system parameters based on SAL's experimental data measured in late 1994 when the Finnigan instrument was relatively new. SAL generated additional data in 1995 to verify the calibration procedures for estimating the dead-time correction factor, the ion-counting conversion factor and the Faraday cup detector efficiency factors. The system parameters estimated on the present data will have to be reestablished when the Finnigan MAT-262 is moved-to the new clean- laboratory. Different methods will be used to analyzed environmental samples than the current measurement methods being used. For example, the environmental samples will be electroplated on a single filament rather than using the current two filament system. An outline of the calibration standard operating procedure (SOP) is included

  20. Calibration of passive remote observing optical and microwave instrumentation; Proceedings of the Meeting, Orlando, FL, Apr. 3-5, 1991

    Science.gov (United States)

    Guenther, Bruce W.

    Various papers on the calibration of passive remote observing optical and microwave instrumentation are presented. Individual topics addressed include: on-board calibration device for a wide field-of-view instrument, calibration for the medium-resolution imaging spectrometer, cryogenic radiometers and intensity-stabilized lasers for EOS radiometric calibrations, radiometric stability of the Shuttle-borne solar backscatter ultraviolet spectrometer, ratioing radiometer for use with a solar diffuser, requirements of a solar diffuser and measurements of some candidate materials, reflectance stability analysis of Spectralon diffuse calibration panels, stray light effects on calibrations using a solar diffuser, radiometric calibration of SPOT 23 HRVs, surface and aerosol models for use in radiative transfer codes. Also addressed are: calibrated intercepts for solar radiometers used in remote sensor calibration, radiometric calibration of an airborne multispectral scanner, in-flight calibration of a helicopter-mounted Daedalus multispectral scanner, technique for improving the calibration of large-area sphere sources, remote colorimetry and its applications, spatial sampling errors for a satellite-borne scanning radiometer, calibration of EOS multispectral imaging sensors and solar irradiance variability. (For individual items see A93-23576 to A93-23603)

  1. U.S. Department of Energy Office of Legacy Management Calibration Facilities - 12103

    Energy Technology Data Exchange (ETDEWEB)

    Barr, Deborah [U.S. Department of Energy Office of Legacy Management, Grand Junction, Colorado (United States); Traub, David; Widdop, Michael [S.M. Stoller Corporation, Grand Junction, Colorado (United States)

    2012-07-01

    This paper describes radiometric calibration facilities located in Grand Junction, Colorado, and at three secondary calibration sites. These facilities are available to the public for the calibration of radiometric field instrumentation for in-situ measurements of radium (uranium), thorium, and potassium. Both borehole and hand-held instruments may be calibrated at the facilities. Aircraft or vehicle mounted systems for large area surveys may be calibrated at the Grand Junction Regional Airport facility. These calibration models are recognized internationally as stable, well-characterized radiation sources for calibration. Calibration models built in other countries are referenced to the DOE models, which are also widely used as a standard for calibration within the U.S. Calibration models are used to calibrate radiation detectors used in uranium exploration, remediation, and homeland security. (authors)

  2. Procedure and device for the radiometric determination of the quantity, quality and foreign substances in moved bulk materials

    International Nuclear Information System (INIS)

    Krone, C.; Jentsch, G.; Berger, J.

    1987-01-01

    This invention has to do with a procedure and device for the simultaneous radiometric determination of quantity, quality and foreign substances in moved bulk materials in particular lignite at one measuring point. The section of the bulk material discharge is transmitted by nuclides for soft and hard gamma radiation in pairs. The pulse rates are registered in pairs by means of detectors and evaluated in real-time operation

  3. A single model procedure for tank calibration function estimation

    International Nuclear Information System (INIS)

    York, J.C.; Liebetrau, A.M.

    1995-01-01

    Reliable tank calibrations are a vital component of any measurement control and accountability program for bulk materials in a nuclear reprocessing facility. Tank volume calibration functions used in nuclear materials safeguards and accountability programs are typically constructed from several segments, each of which is estimated independently. Ideally, the segments correspond to structural features in the tank. In this paper the authors use an extension of the Thomas-Liebetrau model to estimate the entire calibration function in a single step. This procedure automatically takes significant run-to-run differences into account and yields an estimate of the entire calibration function in one operation. As with other procedures, the first step is to define suitable calibration segments. Next, a polynomial of low degree is specified for each segment. In contrast with the conventional practice of constructing a separate model for each segment, this information is used to set up the design matrix for a single model that encompasses all of the calibration data. Estimation of the model parameters is then done using conventional statistical methods. The method described here has several advantages over traditional methods. First, modeled run-to-run differences can be taken into account automatically at the estimation step. Second, no interpolation is required between successive segments. Third, variance estimates are based on all the data, rather than that from a single segment, with the result that discontinuities in confidence intervals at segment boundaries are eliminated. Fourth, the restrictive assumption of the Thomas-Liebetrau method, that the measured volumes be the same for all runs, is not required. Finally, the proposed methods are readily implemented using standard statistical procedures and widely-used software packages

  4. CALIBRATION PROCEDURES ON OBLIQUE CAMERA SETUPS

    Directory of Open Access Journals (Sweden)

    G. Kemper

    2016-06-01

    Full Text Available Beside the creation of virtual animated 3D City models, analysis for homeland security and city planning, the accurately determination of geometric features out of oblique imagery is an important task today. Due to the huge number of single images the reduction of control points force to make use of direct referencing devices. This causes a precise camera-calibration and additional adjustment procedures. This paper aims to show the workflow of the various calibration steps and will present examples of the calibration flight with the final 3D City model. In difference to most other software, the oblique cameras are used not as co-registered sensors in relation to the nadir one, all camera images enter the AT process as single pre-oriented data. This enables a better post calibration in order to detect variations in the single camera calibration and other mechanical effects. The shown sensor (Oblique Imager is based o 5 Phase One cameras were the nadir one has 80 MPIX equipped with a 50 mm lens while the oblique ones capture images with 50 MPix using 80 mm lenses. The cameras are mounted robust inside a housing to protect this against physical and thermal deformations. The sensor head hosts also an IMU which is connected to a POS AV GNSS Receiver. The sensor is stabilized by a gyro-mount which creates floating Antenna –IMU lever arms. They had to be registered together with the Raw GNSS-IMU Data. The camera calibration procedure was performed based on a special calibration flight with 351 shoots of all 5 cameras and registered the GPS/IMU data. This specific mission was designed in two different altitudes with additional cross lines on each flying heights. The five images from each exposure positions have no overlaps but in the block there are many overlaps resulting in up to 200 measurements per points. On each photo there were in average 110 well distributed measured points which is a satisfying number for the camera calibration. In a first

  5. Transponder-aided joint calibration and synchronization compensation for distributed radar systems.

    Science.gov (United States)

    Wang, Wen-Qin

    2015-01-01

    High-precision radiometric calibration and synchronization compensation must be provided for distributed radar system due to separate transmitters and receivers. This paper proposes a transponder-aided joint radiometric calibration, motion compensation and synchronization for distributed radar remote sensing. As the transponder signal can be separated from the normal radar returns, it is used to calibrate the distributed radar for radiometry. Meanwhile, the distributed radar motion compensation and synchronization compensation algorithms are presented by utilizing the transponder signals. This method requires no hardware modifications to both the normal radar transmitter and receiver and no change to the operating pulse repetition frequency (PRF). The distributed radar radiometric calibration and synchronization compensation require only one transponder, but the motion compensation requires six transponders because there are six independent variables in the distributed radar geometry. Furthermore, a maximum likelihood method is used to estimate the transponder signal parameters. The proposed methods are verified by simulation results.

  6. Data acquisition and processing - helicopter radiometric survey, Krageroe, 1998

    CERN Document Server

    Beard, L P

    2000-01-01

    On 07 October 1998 a helicopter radiometric survey was flown in the vicinity of Krageroe municipality. The purpose of the survey was to provide radiometric information to help assess radon hazard from radioactive rocks in the area. A total of 60 line-kilometres of radiometric data were acquired in a single flight, covering an area of approximately 3 square km with a 50-m line spacing. The data were collected by Geological Survey of Norway (NGU) personnel and processed at NGU. Radiometric data were reduced using the three-channel procedure recommended by the International Atomic Energy Association. All data were gridded using square cells with 30-m sides and geophysical maps were produced at a scale of 1:5000. This report covers aspects of data acquisition and processing (Author)

  7. Data acquisition and processing - helicopter radiometric survey, Krageroe, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Beard, Les P.; Mogaard, John Olav

    2000-07-01

    On 07 October 1998 a helicopter radiometric survey was flown in the vicinity of Krageroe municipality. The purpose of the survey was to provide radiometric information to help assess radon hazard from radioactive rocks in the area. A total of 60 line-kilometres of radiometric data were acquired in a single flight, covering an area of approximately 3 square km with a 50-m line spacing. The data were collected by Geological Survey of Norway (NGU) personnel and processed at NGU. Radiometric data were reduced using the three-channel procedure recommended by the International Atomic Energy Association. All data were gridded using square cells with 30-m sides and geophysical maps were produced at a scale of 1:5000. This report covers aspects of data acquisition and processing (Author)

  8. Calibration procedure for Slocum glider deployed optical instruments.

    Science.gov (United States)

    Cetinić, Ivona; Toro-Farmer, Gerardo; Ragan, Matthew; Oberg, Carl; Jones, Burton H

    2009-08-31

    Recent developments in the field of the autonomous underwater vehicles allow the wide usage of these platforms as part of scientific experiments, monitoring campaigns and more. The vehicles are often equipped with sensors measuring temperature, conductivity, chlorophyll a fluorescence (Chl a), colored dissolved organic matter (CDOM) fluorescence, phycoerithrin (PE) fluorescence and spectral volume scattering function at 117 degrees, providing users with high resolution, real time data. However, calibration of these instruments can be problematic. Most in situ calibrations are performed by deploying complementary instrument packages or water samplers in the proximity of the glider. Laboratory calibrations of the mounted sensors are difficult due to the placement of the instruments within the body of the vehicle. For the laboratory calibrations of the Slocum glider instruments we developed a small calibration chamber where we can perform precise calibrations of the optical instruments aboard our glider, as well as sensors from other deployment platforms. These procedures enable us to obtain pre- and post-deployment calibrations for optical fluorescence instruments, which may differ due to the biofouling and other physical damage that can occur during long-term glider deployments. We found that biofouling caused significant changes in the calibration scaling factors of fluorescent sensors, suggesting the need for consistent and repetitive calibrations for gliders as proposed in this paper.

  9. On-ground calibration of the BEPICOLOMBO/SIMBIO-SYS at instrument level

    Science.gov (United States)

    Rodriguez-Ferreira, J.; Poulet, F.; Eng, P.; Longval, Y.; Dassas, K.; Arondel, A.; Langevin, Y.; Capaccioni, F.; Filacchione, G.; Palumbo, P.; Cremonese, G.; Dami, M.

    2012-04-01

    The Mercury Planetary Orbiter/BepiColombo carries an integrated suite of instruments, the Spectrometer and Imagers for MPO BepiColombo-Integrated Observatory SYStem (SIMBIO-SYS). SIMBIO-SYS has 3 channels: a stereo imaging system (STC), a high-resolution imager (HRIC) and a visible-near-infrared imaging spectrometer (VIHI). SIMBIO-SYS will scan the surface of Mercury with these three channels and determine the physical, morphological and compositional properties of the entire planet. Before integration on the S/C, an on-ground calibration at the channels and at the instrument levels will be performed so as to describe the instrumental responses as a function of various parameters that might evolve while the instruments will be operating [1]. The Institut d'Astrophysique Spatiale (IAS) is responsible for the on-ground instrument calibration at the instrument level. During the 4 weeks of calibration campaign planned for June 2012, the instrument will be maintained in a mechanical and thermal environment simulating the space conditions. Four Optical stimuli (QTH lamp, Integrating Sphere, BlackBody with variable temperature from 50 to 1200°C and Monochromator), are placed over an optical bench to illuminate the four channels so as to make the radiometric calibration, straylight monitoring, as well as spectral proofing based on laboratory mineral samples. The instrument will be mounted on a hexapod placed inside a thermal vacuum chamber during the calibration campaign. The hexapod will move the channels within the well-characterized incoming beam. We will present the key activities of the preparation of this calibration: the derivation of the instrument radiometric model, the implementation of the optical, mechanical and software interfaces of the calibration assembly, the characterization of the optical bench and the definition of the calibration procedures.

  10. Mathematical calibration procedure of a capacitive sensor-based indexed metrology platform

    International Nuclear Information System (INIS)

    Brau-Avila, A; Valenzuela-Galvan, M; Herrera-Jimenez, V M; Santolaria, J; Aguilar, J J; Acero, R

    2017-01-01

    The demand for faster and more reliable measuring tasks for the control and quality assurance of modern production systems has created new challenges for the field of coordinate metrology. Thus, the search for new solutions in coordinate metrology systems and the need for the development of existing ones still persists. One example of such a system is the portable coordinate measuring machine (PCMM), the use of which in industry has considerably increased in recent years, mostly due to its flexibility for accomplishing in-line measuring tasks as well as its reduced cost and operational advantages compared to traditional coordinate measuring machines. Nevertheless, PCMMs have a significant drawback derived from the techniques applied in the verification and optimization procedures of their kinematic parameters. These techniques are based on the capture of data with the measuring instrument from a calibrated gauge object, fixed successively in various positions so that most of the instrument measuring volume is covered, which results in time-consuming, tedious and expensive verification and optimization procedures. In this work the mathematical calibration procedure of a capacitive sensor-based indexed metrology platform (IMP) is presented. This calibration procedure is based on the readings and geometric features of six capacitive sensors and their targets with nanometer resolution. The final goal of the IMP calibration procedure is to optimize the geometric features of the capacitive sensors and their targets in order to use the optimized data in the verification procedures of PCMMs. (paper)

  11. Mathematical calibration procedure of a capacitive sensor-based indexed metrology platform

    Science.gov (United States)

    Brau-Avila, A.; Santolaria, J.; Acero, R.; Valenzuela-Galvan, M.; Herrera-Jimenez, V. M.; Aguilar, J. J.

    2017-03-01

    The demand for faster and more reliable measuring tasks for the control and quality assurance of modern production systems has created new challenges for the field of coordinate metrology. Thus, the search for new solutions in coordinate metrology systems and the need for the development of existing ones still persists. One example of such a system is the portable coordinate measuring machine (PCMM), the use of which in industry has considerably increased in recent years, mostly due to its flexibility for accomplishing in-line measuring tasks as well as its reduced cost and operational advantages compared to traditional coordinate measuring machines. Nevertheless, PCMMs have a significant drawback derived from the techniques applied in the verification and optimization procedures of their kinematic parameters. These techniques are based on the capture of data with the measuring instrument from a calibrated gauge object, fixed successively in various positions so that most of the instrument measuring volume is covered, which results in time-consuming, tedious and expensive verification and optimization procedures. In this work the mathematical calibration procedure of a capacitive sensor-based indexed metrology platform (IMP) is presented. This calibration procedure is based on the readings and geometric features of six capacitive sensors and their targets with nanometer resolution. The final goal of the IMP calibration procedure is to optimize the geometric features of the capacitive sensors and their targets in order to use the optimized data in the verification procedures of PCMMs.

  12. Calibration procedure and wavelength correction for neutron depolarization experiments

    International Nuclear Information System (INIS)

    Roest, W.; Rekveldt, M.T.

    1992-01-01

    The neutron polarimeter, for which an extended calibration procedure is described here, enables one to investigate magnetic properties of materials. Such an investigation is carried out by offering a polarized neutron beam in the x-, y- and z-direction successively and, after transmission through the sample, by analysing the polarization in all three directions. The result is a 3x3 depolarization matrix. After the polarizer, the neutron beam has a polarization along the z-direction. Two coil systems creating a magnetic field in the yz-plane perpendicular to the beam direction provide the possibility to direct the polarization in the x-, y- and z-direction by means of Larmor precession of the polarization in these fields. New research areas, where small depolarization effects together with considerable polarization rotation are measured, have caused a need for more accuracy in, and better knowledge of the calibration of the polarimeter. The calibration procedure use up to now and the improvements made on it are described. (orig.)

  13. Detection and recovery of mycobacteria by a radiometric procedure

    International Nuclear Information System (INIS)

    Takahashi, H.; Foster, V.

    1983-01-01

    During a 6-month period, 5,375 clinical specimens were cultured on Middlebrook-Cohn 7H10 medium, on Lowenstein-Jensen medium, and in Middlebrook 7H12 medium containing [ 14 C]palmitic acid. More mycobacteria were recovered when all three media were used than when either the conventional method with 7H10 agar and Lowenstein-Jensen slants or the radiometric method with 7H12 broth was used alone

  14. Optimized procedure for calibration and verification multileaf collimator from Elekta Synergy accelerator

    International Nuclear Information System (INIS)

    Castel Millan, A.; Perellezo Mazon, A.; Fernandez Ibiza, J.; Arnalte Olloquequi, M.; Armengol Martinez, S.; Rodriguez Rey, A.; Guedea Edo, F.

    2011-01-01

    The objective of this work is to design an optimized procedure for calibration and verification of a multileaf collimator used so as to allow the EPID and the image plate in a complementary way, using different processing systems. With this procedure we have two equivalent alternative as the same parameters obtained for the calibration of multileaf Elekta Synergy accelerator.

  15. Computational integration of the phases and procedures of calibration processes for radioprotection

    International Nuclear Information System (INIS)

    Santos, Gleice R. dos; Thiago, Bibiana dos S.; Rocha, Felicia D.G.; Santos, Gelson P. dos; Potiens, Maria da Penha A.; Vivolo, Vitor

    2011-01-01

    This work proceed the computational integration of the processes phases by using only a single computational software, from the entrance of the instrument at the Instrument Calibration Laboratory (LCI-IPEN) to the conclusion of calibration procedures. So, the initial information such as trade mark, model, manufacturer, owner, and the calibration records are digitized once until the calibration certificate emission

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

    Science.gov (United States)

    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.

  17. The Impact of Indoor and Outdoor Radiometer Calibration on Solar Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Habte, Aron; Sengupta, Manajit; Andreas, Afshin; Reda, Ibrahim; Robinson, Justin

    2016-06-02

    This study addresses the effect of calibration methodologies on calibration responsivities and the resulting impact on radiometric measurements. The calibration responsivities used in this study are provided by NREL's broadband outdoor radiometer calibration (BORCAL) and a few prominent manufacturers. The BORCAL method provides outdoor calibration responsivity of pyranometers and pyrheliometers at a 45 degree solar zenith angle and responsivity as a function of solar zenith angle determined by clear-sky comparisons to reference irradiance. The BORCAL method also employs a thermal offset correction to the calibration responsivity of single-black thermopile detectors used in pyranometers. Indoor calibrations of radiometers by their manufacturers are performed using a stable artificial light source in a side-by-side comparison of the test radiometer under calibration to a reference radiometer of the same type. These different methods of calibration demonstrated 1percent to 2 percent differences in solar irradiance measurement. Analyzing these values will ultimately enable a reduction in radiometric measurement uncertainties and assist in developing consensus on a standard for calibration.

  18. Development of absolute radiometric response functions for HyPlant & G-LiHT using SIRCUS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to provide absolute radiometric and cross-calibrated spectral characterizations for G-LiHT and HyPlant.  The objectives are: (i) to...

  19. Radiometric titration of diethanolamine with 65ZnSO4 and determination of mono and diethanolamines in a mixture by a radiometric method

    International Nuclear Information System (INIS)

    Varadan, R.; Sriman Narayanan, S.; Rao, V.R.S.

    1984-01-01

    Radiometric titration of diethanolamine with 65 ZnSO 4 is reported. Determination of individual amounts of mono- and diethanolamines in a mixture is described. The procedure is simple, rapid and accurate. (author)

  20. Calibration and verification of surface contamination meters --- Procedures and techniques

    International Nuclear Information System (INIS)

    Schuler, C; Butterweck, G.; Wernli, C.; Bochud, F.; Valley, J.-F.

    2007-03-01

    A standardised measurement procedure for surface contamination meters (SCM) is presented. The procedure aims at rendering surface contamination measurements to be simply and safely interpretable. Essential for the approach is the introduction and common use of the radionuclide specific quantity 'guideline value' specified in the Swiss Radiation Protection Ordinance as unit for the measurement of surface activity. The according radionuclide specific 'guideline value count rate' can be summarized as verification reference value for a group of radionuclides ('basis guideline value count rate'). The concept can be generalized for SCM of the same type or for SCM of different types using he same principle of detection. A SCM multi source calibration technique is applied for the determination of the instrument efficiency. Four different electron radiation energy regions, four different photon radiation energy regions and an alpha radiation energy region are represented by a set of calibration sources built according to ISO standard 8769-2. A guideline value count rate representing the activity per unit area of a surface contamination of one guideline value can be calculated for any radionuclide using instrument efficiency, radionuclide decay data, contamination source efficiency, guideline value averaging area (100 cm 2 ), and radionuclide specific guideline value. n this way, instrument responses for the evaluation of surface contaminations are obtained for radionuclides without available calibration sources as well as for short-Iived radionuclides, for which the continuous replacement of certified calibration sources can lead to unreasonable costs. SCM verification is based on surface emission rates of reference sources with an active area of 100 cm 2 . The verification for a given list of radionuclides is based on the radionuclide specific quantity guideline value count rate. Guideline value count rates for groups of radionuclides can be represented within the maximum

  1. Reduction procedures for accurate analysis of MSX surveillance experiment data

    Science.gov (United States)

    Gaposchkin, E. Mike; Lane, Mark T.; Abbot, Rick I.

    1994-01-01

    Technical challenges of the Midcourse Space Experiment (MSX) science instruments require careful characterization and calibration of these sensors for analysis of surveillance experiment data. Procedures for reduction of Resident Space Object (RSO) detections will be presented which include refinement and calibration of the metric and radiometric (and photometric) data and calculation of a precise MSX ephemeris. Examples will be given which support the reduction, and these are taken from ground-test data similar in characteristics to the MSX sensors and from the IRAS satellite RSO detections. Examples to demonstrate the calculation of a precise ephemeris will be provided from satellites in similar orbits which are equipped with S-band transponders.

  2. Brookhaven National Laboratory meteorological services instrument calibration plan and procedures

    Energy Technology Data Exchange (ETDEWEB)

    Heiser, John [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2013-02-16

    This document describes the Meteorological Services (Met Services) Calibration and Maintenance Schedule and Procedures, The purpose is to establish the frequency and mechanism for the calibration and maintenance of the network of meteorological instrumentation operated by Met Services. The goal is to maintain the network in a manner that will result in accurate, precise and reliable readings from the instrumentation.

  3. Using genetic algorithm and TOPSIS for Xinanjiang model calibration with a single procedure

    Science.gov (United States)

    Cheng, Chun-Tian; Zhao, Ming-Yan; Chau, K. W.; Wu, Xin-Yu

    2006-01-01

    Genetic Algorithm (GA) is globally oriented in searching and thus useful in optimizing multiobjective problems, especially where the objective functions are ill-defined. Conceptual rainfall-runoff models that aim at predicting streamflow from the knowledge of precipitation over a catchment have become a basic tool for flood forecasting. The parameter calibration of a conceptual model usually involves the multiple criteria for judging the performances of observed data. However, it is often difficult to derive all objective functions for the parameter calibration problem of a conceptual model. Thus, a new method to the multiple criteria parameter calibration problem, which combines GA with TOPSIS (technique for order performance by similarity to ideal solution) for Xinanjiang model, is presented. This study is an immediate further development of authors' previous research (Cheng, C.T., Ou, C.P., Chau, K.W., 2002. Combining a fuzzy optimal model with a genetic algorithm to solve multi-objective rainfall-runoff model calibration. Journal of Hydrology, 268, 72-86), whose obvious disadvantages are to split the whole procedure into two parts and to become difficult to integrally grasp the best behaviors of model during the calibration procedure. The current method integrates the two parts of Xinanjiang rainfall-runoff model calibration together, simplifying the procedures of model calibration and validation and easily demonstrated the intrinsic phenomenon of observed data in integrity. Comparison of results with two-step procedure shows that the current methodology gives similar results to the previous method, is also feasible and robust, but simpler and easier to apply in practice.

  4. Use of Radiometric Survey Data for Environmental Study: The Case of Northern Sumatera

    International Nuclear Information System (INIS)

    Tjokrokardono, S; Ramadanus; Sustarman, H

    1998-01-01

    The convertion of old radiometric data obtained from former uranium exploration activities in northem sumatra into radiation exposure has been evaluated. The objective of the study is to find an alternative way for cheaper and faster compilation of radiation exposure database for environmental study purposes. The old radiometric data measure from the outcrops has been plotted 1;250.000, 1;100.000, and 1;50.000 map scales. The data are translated into 1;1000.000 map scale before they are converted into 1;1000.000 radiation exposure rate map using a graphic method. The radiation exposure rate in northem sumatera falls between 25 R/hour to 40 R/hour. The benefit offered using this method is that it provides a cheaper and faster production of radiation exposure rate map from old radiometric map. However, the problems arising from such a production is that the radiometric data provide unhomogeneous data distributions and densities among the area. As a conclusion it is recommended to recollect some of the data at designated area using well calibrated SPP2NF and gamma ray spectrometer instruments

  5. JPSS-1 VIIRS Pre-Launch Radiometric Performance

    Science.gov (United States)

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

    2015-01-01

    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 kilometers) cross-track scanning radiometer with spatial resolutions of 370 and 740 meters 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 microns to 12.01 microns]. 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.

  6. Supervised Vicarious Calibration (SVC of Multi-Source Hyperspectral Remote-Sensing Data

    Directory of Open Access Journals (Sweden)

    Anna Brook

    2015-05-01

    Full Text Available Introduced in 2011, the supervised vicarious calibration (SVC approach is a promising approach to radiometric calibration and atmospheric correction of airborne hyperspectral (HRS data. This paper presents a comprehensive study by which the SVC method has been systematically examined and a complete protocol for its practical execution has been established—along with possible limitations encountered during the campaign. The technique was applied to multi-sourced HRS data in order to: (1 verify the at-sensor radiometric calibration and (2 obtain radiometric and atmospheric correction coefficients. Spanning two select study sites along the southeast coast of France, data were collected simultaneously by three airborne sensors (AisaDUAL, AHS and CASI-1500i aboard two aircrafts (CASA of National Institute for Aerospace Technology INTA ES and DORNIER 228 of NERC-ARSF Centre UK. The SVC ground calibration site was assembled along sand dunes near Montpellier and the thematic data were acquired from other areas in the south of France (Salon-de-Provence, Marseille, Avignon and Montpellier on 28 October 2010 between 12:00 and 16:00 UTC. The results of this study confirm that the SVC method enables reliable inspection and, if necessary, in-situ fine radiometric recalibration of airborne hyperspectral data. Independent of sensor or platform quality, the SVC approach allows users to improve at-sensor data to obtain more accurate physical units and subsequently improved reflectance information. Flight direction was found to be important, whereas the flight altitude posed very low impact. The numerous rules and major outcomes of this experiment enable a new standard of atmospherically corrected data based on better radiometric output. Future research should examine the potential of SVC to be applied to super-and-hyperspectral data obtained from on-orbit sensors.

  7. Reduction of Radiometric Miscalibration—Applications to Pushbroom Sensors

    Directory of Open Access Journals (Sweden)

    Sigrid Roessner

    2011-06-01

    Full Text Available 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.

  8. Reduction of Radiometric Miscalibration—Applications to Pushbroom Sensors

    Science.gov (United States)

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

    International Nuclear Information System (INIS)

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

    1981-01-01

    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

  10. Nuclear fuel technology - Tank calibration and volume determination for nuclear materials accountancy - Part 1: Procedural overview

    International Nuclear Information System (INIS)

    2007-01-01

    Accurate determinations of volume are a fundamental component of any measurement-based system of control and accountability in a facility that processes or stores nuclear materials in liquid form. Volume determinations are typically made with the aid of a calibration or volume measurement equation that relates the response of the tank's measurement system to some independent measure of tank volume. The ultimate purpose of the calibration exercise is to estimate the tank's volume measurement equation (the inverse of the calibration equation), which relates tank volume to measurement system response. The steps carried out to acquire data for estimating the tank's calibration or volume measurement equation are collectively described as the process of tank calibration. This part of ISO 18213 describes procedures for tank calibration and volume determination for nuclear process tanks equipped with pressure-measurement systems for determining liquid content. Specifically, overall guidance is provided for planning a calibration exercise undertaken to obtain the data required for the measurement equation to estimate a tank's volume. The key steps in the procedure are also presented for subsequently using the estimated volume-measurement equation to determine tank liquid volumes. The procedures presented apply specifically to tanks equipped with bubbler probe systems for measuring liquid content. Moreover, these procedures produce reliable results only for clear (i.e. without suspended solids), homogeneous liquids that are at both thermal and static equilibrium. The paper elaborates on scope, physical principles involved, the calibration model, equipment required, a typical tank calibration procedure, calibration planning and pre-calibration activities, and volume determination. A bibliography is provided

  11. Radiometric titration of diethanolamine with /sup 65/ZnSO/sub 4/ and determination of mono and diethanolamines in a mixture by a radiometric method

    Energy Technology Data Exchange (ETDEWEB)

    Varadan, R.; Sriman Narayanan, S.; Rao, V.R.S. (Indian Inst. of Tech., Madras. Dept. of Chemistry)

    1984-08-16

    Radiometric titration of diethanolamine with /sup 65/ZnSO/sub 4/ is reported. Determination of individual amounts of mono- and diethanolamines in a mixture is described. The procedure is simple, rapid and accurate.

  12. Standard Test Method for Calibration of Non-Concentrator Photovoltaic Secondary Reference Cells

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers calibration and characterization of secondary terrestrial photovoltaic reference cells to a desired reference spectral irradiance distribution. The recommended physical requirements for these reference cells are described in Specification E1040. Reference cells are principally used in the determination of the electrical performance of a photovoltaic device. 1.2 Secondary reference cells are calibrated indoors using simulated sunlight or outdoors in natural sunlight by reference to a primary reference cell previously calibrated to the same desired reference spectral irradiance distribution. 1.3 Secondary reference cells calibrated according to this test method will have the same radiometric traceability as the of the primary reference cell used for the calibration. Therefore, if the primary reference cell is traceable to the World Radiometric Reference (WRR, see Test Method E816), the resulting secondary reference cell will also be traceable to the WRR. 1.4 This test method appli...

  13. Normalization and calibration of geostationary satellite radiances for the International Satellite Cloud Climatology Project

    Science.gov (United States)

    Desormeaux, Yves; Rossow, William B.; Brest, Christopher L.; Campbell, G. G.

    1993-01-01

    Procedures are described for normalizing the radiometric calibration of image radiances obtained from geostationary weather satellites that contributed data to the International Satellite Cloud Climatology Project. The key step is comparison of coincident and collocated measurements made by each satellite and the concurrent AVHRR on the 'afternoon' NOAA polar-orbiting weather satellite at the same viewing geometry. The results of this comparison allow transfer of the AVHRR absolute calibration, which has been established over the whole series, to the radiometers on the geostationary satellites. Results are given for Meteosat-2, 3, and 4, for GOES-5, 6, and 7, for GMS-2, 3, and 4 and for Insat-1B. The relative stability of the calibrations of these radiance data is estimated to be within +/- 3 percent; the uncertainty of the absolute calibrations is estimated to be less than 10 percent. The remaining uncertainties are at least two times smaller than for the original radiance data.

  14. Assessment and Correction of on-Orbit Radiometric Calibration for FY-3 VIRR Thermal Infrared Channels

    Directory of Open Access Journals (Sweden)

    Na Xu

    2014-03-01

    Full Text Available FengYun-3 (FY-3 Visible Infrared Radiometer (VIRR, along with its predecessor, Multispectral Visible Infrared Scanning Radiometer (MVISR, onboard FY-1C&D have had continuous global observation more than 14 years. This data record is valuable for weather prediction, climate monitoring, and environment research. Data quality is vital for satellite data assimilations in Numerical Weather Prediction (NWP and quantitative remote sensing applications. In this paper, the accuracies of radiometric calibration for VIRR onboard FY-3A and FY-3B, in thermal infrared (TIR channels, are evaluated using the Low Earth Orbit (LEO-LEO simultaneous nadir overpass intercalibration method. Hyperspectral and high-quality observations from Infrared Atmosphere Sounding Instrument (IASI onboard METOP-A are used as reference. The biases of VIRR measurements with respect to IASI over one-and-a-half years indicate that the TIR calibration accuracy of FY-3B VIRR is better than that of FY-3A VIRR. The brightness temperature (BT measured by FY-3A/VIRR is cooler than that measured by IASI with monthly mean biases ranging from −2 K to −1 K for channel 4 and −1 K to 0.2 K for channel 5. Measurements from FY-3B/VIRR are more consistent with that from IASI, and the annual mean biases are 0.84 ± 0.16 K and −0.66 ± 0.18 K for channels 4 and 5, respectively. The BT biases of FY-3A/VIRR show scene temperature-dependence and seasonal variation, which are not found from FY-3B/VIRR BT biases. The temperature-dependent biases are shown to be attributed to the nonlinearity of detectors. New nonlinear correction coefficients of FY-3A/VIRR TIR channels are reevaluated using various collocation samples. Verification results indicate that the use of the new nonlinear correction can greatly correct the scene temperature-dependent and systematic biases.

  15. RADIOMETRIC NORMALIZATION OF LARGE AIRBORNE IMAGE DATA SETS ACQUIRED BY DIFFERENT SENSOR TYPES

    Directory of Open Access Journals (Sweden)

    S. Gehrke

    2016-06-01

    Full Text Available 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

  16. Processing data collected from radiometric experiments by multivariate technique

    International Nuclear Information System (INIS)

    Urbanski, P.; Kowalska, E.; Machaj, B.; Jakowiuk, A.

    2005-01-01

    Multivariate techniques applied for processing data collected from radiometric experiments can provide more efficient extraction of the information contained in the spectra. Several techniques are considered: (i) multivariate calibration using Partial Least Square Regression and Artificial Neural Network, (ii) standardization of the spectra, (iii) smoothing of collected spectra were autocorrelation function and bootstrap were used for the assessment of the processed data, (iv) image processing using Principal Component Analysis. Application of these techniques is illustrated on examples of some industrial applications. (author)

  17. Method for improving the use of PASCO brand spectrophotometer using DataStudio program applied to radiometric surveys for LAFTLA

    International Nuclear Information System (INIS)

    Bolanos Rodriguez, Gary

    2008-01-01

    Escuela de Ingenieria Electrica at the Universidad de Costa Rica has developed a procedure for the improved use of a PASCO brand Spectrophotometer of the Laboratorio de Fotonica y Tecnologia Laser Aplicada. The program has used DataStudio for the application in radiometric surveys in LAFTLA. Important conclusions have been obtained by the assembly of optical experiments, software and data collection and analysis, such as the behavior of a emitting source radiation known as black body and its relation to the temperature, wavelength and intensity of light. The user guide has been detailed exposing calibrations of the sensors, the definition of constants needed for obtaining parameters and assembly and commissioning of the equipment. (author) [es

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

    International Nuclear Information System (INIS)

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

    1981-01-01

    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

  19. High-precision reflectivity measurements: improvements in the calibration procedure

    Science.gov (United States)

    Jupe, Marco; Grossmann, Florian; Starke, Kai; Ristau, Detlev

    2003-05-01

    The development of high quality optical components is heavily depending on precise characterization procedures. The reflectance and transmittance of laser components are the most important parameters for advanced laser applications. In the industrial fabrication of optical coatings, quality management is generally insured by spectral photometric methods according to ISO/DIS 15386 on a medium level of accuracy. Especially for high reflecting mirrors, a severe discrepancy in the determination of the absolute reflectivity can be found for spectral photometric procedures. In the first part of the CHOCLAB project, a method for measuring reflectance and transmittance with an enhanced precision was developed, which is described in ISO/WD 13697. In the second part of the CHOCLAB project, the evaluation and optimization for the presented method is scheduled. Within this framework international Round-Robin experiment is currently in progress. During this Round-Robin experiment, distinct deviations could be observed between the results of high precision measurement facilities of different partners. Based on the extended experiments, the inhomogeneity of the sample reflectivity was identified as one important origin for the deviation. Consequently, this inhomogeneity is also influencing the calibration procedure. Therefore, a method was developed that allows the calibration of the chopper blade using always the same position on the reference mirror. During the investigations, the homogeneity of several samples was characterized by a surface mapping procedure for 1064 nm. The measurement facility was extended to the additional wavelength 532 nm and a similar set-up was assembled at 10.6 μm. The high precision reflectivity procedure at the mentioned wavelengths is demonstrated for exemplary measurements.

  20. Calibration and correction procedures for cosmic-ray neutron soil moisture probes located across Australia

    Science.gov (United States)

    Hawdon, Aaron; McJannet, David; Wallace, Jim

    2014-06-01

    The cosmic-ray probe (CRP) provides continuous estimates of soil moisture over an area of ˜30 ha by counting fast neutrons produced from cosmic rays which are predominantly moderated by water molecules in the soil. This paper describes the setup, measurement correction procedures, and field calibration of CRPs at nine locations across Australia with contrasting soil type, climate, and land cover. These probes form the inaugural Australian CRP network, which is known as CosmOz. CRP measurements require neutron count rates to be corrected for effects of atmospheric pressure, water vapor pressure changes, and variations in incoming neutron intensity. We assess the magnitude and importance of these corrections and present standardized approaches for network-wide analysis. In particular, we present a new approach to correct for incoming neutron intensity variations and test its performance against existing procedures used in other studies. Our field calibration results indicate that a generalized calibration function for relating neutron counts to soil moisture is suitable for all soil types, with the possible exception of very sandy soils with low water content. Using multiple calibration data sets, we demonstrate that the generalized calibration function only applies after accounting for persistent sources of hydrogen in the soil profile. Finally, we demonstrate that by following standardized correction procedures and scaling neutron counting rates of all CRPs to a single reference location, differences in calibrations between sites are related to site biomass. This observation provides a means for estimating biomass at a given location or for deriving coefficients for the calibration function in the absence of field calibration data.

  1. Metrological reliability of the calibration procedure in terms of air kerma using the ionization chamber NE2575

    International Nuclear Information System (INIS)

    Guimaraes, Margarete Cristina; Silva, Teogenes Augusto da; Rosado, Paulo H.G.

    2016-01-01

    Metrology laboratories are expected to provide X radiation beams that were established by international standardization organizations to perform calibration and testing of dosimeters. Reliable and traceable standard dosimeters should be used in the calibration procedure. The aim of this work was to study the reliability of the NE 2575 ionization chamber used as standard dosimeter for the air kerma calibration procedure adopted in the CDTN Calibration Laboratory. (author)

  2. Radiometric calibration of a polarization-sensitive sensor

    International Nuclear Information System (INIS)

    Ahmad, S.P.; Markham, B.L.

    1992-01-01

    The radiometric accuracy of a sensor is adversely affected by scene polarization if its optical system is sensitive to polarization. Tests performed on the reflective bands of the NS001 Thematic Mapper simulator, an aircraft multispectral scanner, show that it is very sensitive to the polarization state of the incoming radiations. For 100 percent linearly polarized light, errors in the measured intensity vary from -40 to +40 percent, depending on the scan angle and spectral band. To estimate polarization-induced errors in the intensity measured at aircraft level, the intensity and polarization of the atmospheric radiances were simulated using a realistic earth-atmosphere radiative transfer model. For the polarization of atmospheric radiances in the solar meridian plane over a vegetated target, intensity errors may range from -10 to + 10 percent. The polarization-induced errors are highest in the shortest NS001 spectral band (0.450-0.525 microns) because of large atmospheric polarizations contributed by Rayleigh particles and small diluting effects caused by the small contributions of weakly polarized radiations coming from aerosols and the surface. Depending on the illumination and view angles, the errors in derived surface reflectance due to the radiance errors can be very large. In particular, for large off-nadir view angles in the forward scattered direction when the sun is low, the relative errors in the derived surface reflectance can be as large as 4 to 5 times the relative error in the radiances. Polarization sensitivity errors cannot be neglected for the shorter wavelengths when the surface reflectance contribution to atmospheric radiances is very small. 40 refs

  3. FTIR Calibration Methods and Issues

    Science.gov (United States)

    Perron, Gaetan

    Over the past 10 years, several space-borne FTIR missions were launched for atmospheric research, environmental monitoring and meteorology. One can think of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) launched by the European Space Agency, the Atmospheric Chemistry Experiment (ACE) launched by the Canadian Space Agency, the Tropospheric Emission Spectrometer (TES) launched by NASA and the Infrared Atmospheric Sounding Interferometer (IASI) launched by Eumetsat in Europe. Others are near to be launched, namely the Cross-track Infrared Sounder (CrIS) from the Integrated Program Of- fice in the United States and the Thermal And Near infrared Sensor for carbon Observation (TANSO) from the Japan Aerospace Exploration Agency. Moreover, several missions under definition foresee the use of this technology as sensor, e.g. Meteosat Third Generation (MTG), Eumetsat Polar System (EPS) and the Premier mission, one of the six candidates of the next ESA Earth Explorer Core Mission. In order to produce good quality products, calibration is essential. Calibrated data is the output of three main sub-systems that are tightly coupled: the instrument, the calibration targets and the level 1B processor. Calibration requirements must be carefully defined and propagated to each sub-system. Often, they are carried out by different parties which add to the complexity. Under budget and schedule pressure, some aspects are sometimes neglected and jeopardized final quality. For space-borne FTIR, level 1B outputs are spectra that are radiometrically, spectrally calibrated and geolocated. Radiometric calibration means to assign an intensity value in units to the y-axis. Spectral calibration means to assign to the x-axis the proper frequency value in units. Finally, geolocated means to assign a target position over the earth geoid i.e. longitude, latitude and altitude. This paper will present calibration methods and issues related to space-borne FTIR missions, e.g. two

  4. Neutron activation procedures used for the calibration of a nitrogen-16 reactor power monitor

    International Nuclear Information System (INIS)

    Jester, W.A.; Daubenspeck, T.

    2000-01-01

    Personnel from the Pennsylvania State University's Breazeale Nuclear Reactor assisted NRC (Nuclear Research Corporation) personnel in calibrating a new MSL/ 16 N Nitrogen-16 Monitor. Neutron flux calibration procedures utilized and the results obtained for the production of a nitrogen-16 source of known activity for a BGO detector calibration are described. (author)

  5. Assessment of the Short-Term Radiometric Stability between Terra MODIS and Landsat 7 ETM+ Sensors

    Science.gov (United States)

    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

  6. The Chandra Source Catalog 2.0: Calibrations

    Science.gov (United States)

    Graessle, Dale E.; Evans, Ian N.; Rots, Arnold H.; Allen, Christopher E.; Anderson, Craig S.; Budynkiewicz, Jamie A.; Burke, Douglas; Chen, Judy C.; Civano, Francesca Maria; D'Abrusco, Raffaele; Doe, Stephen M.; Evans, Janet D.; Fabbiano, Giuseppina; Gibbs, Danny G., II; Glotfelty, Kenny J.; Grier, John D.; Hain, Roger; Hall, Diane M.; Harbo, Peter N.; Houck, John C.; Lauer, Jennifer L.; Laurino, Omar; Lee, Nicholas P.; Martínez-Galarza, Juan Rafael; McCollough, Michael L.; McDowell, Jonathan C.; Miller, Joseph; McLaughlin, Warren; Morgan, Douglas L.; Mossman, Amy E.; Nguyen, Dan T.; Nichols, Joy S.; Nowak, Michael A.; Paxson, Charles; Plummer, David A.; Primini, Francis Anthony; Siemiginowska, Aneta; Sundheim, Beth A.; Tibbetts, Michael; Van Stone, David W.; Zografou, Panagoula

    2018-01-01

    Among the many enhancements implemented for the release of Chandra Source Catalog (CSC) 2.0 are improvements in the processing calibration database (CalDB). We have included a thorough overhaul of the CalDB software used in the processing. The software system upgrade, called "CalDB version 4," allows for a more rational and consistent specification of flight configurations and calibration boundary conditions. Numerous improvements in the specific calibrations applied have also been added. Chandra's radiometric and detector response calibrations vary considerably with time, detector operating temperature, and position on the detector. The CalDB has been enhanced to provide the best calibrations possible to each observation over the fifteen-year period included in CSC 2.0. Calibration updates include an improved ACIS contamination model, as well as updated time-varying gain (i.e., photon energy) and quantum efficiency maps for ACIS and HRC-I. Additionally, improved corrections for the ACIS quantum efficiency losses due to CCD charge transfer inefficiency (CTI) have been added for each of the ten ACIS detectors. These CTI corrections are now time and temperature-dependent, allowing ACIS to maintain a 0.3% energy calibration accuracy over the 0.5-7.0 keV range for any ACIS source in the catalog. Radiometric calibration (effective area) accuracy is estimated at ~4% over that range. We include a few examples where improvements in the Chandra CalDB allow for improved data reduction and modeling for the new CSC.This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.

  7. A multivariate calibration procedure for the tensammetric determination of detergents

    NARCIS (Netherlands)

    Bos, M.

    1989-01-01

    A multivariate calibration procedure based on singular value decomposition (SVD) and the Ho-Kashyap algorithm is used for the tensammetric determination of the cationic detergents Hyamine 1622, benzalkonium chloride (BACl), N-cetyl-N,N,N-trimethylammonium bromide (CTABr) and mixtures of CTABr and

  8. Early Assessment of VIIRS On-Orbit Calibration and Support Activities

    Science.gov (United States)

    Xiong, Xiaoxiong; Chiang, Kwofu; McIntire, Jeffrey; Oudrari, Hassan; Wu, Aisheng; Schwaller, Mathew; Butler, James

    2012-01-01

    The Suomi National Polar-orbiting Partnership (S-NPP) satellite, formally the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP), provides a bridge between current and future low-Earth orbiting weather and environmental observation satellite systems. The NASA s NPP VIIRS Characterization Support Team (VCST) is designed to assess the long term geometric and radiometric performance of the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument onboard the S-NPP spacecraft and to support NPP Science Team Principal Investigators (PI) for their independent evaluation of VIIRS Environmental Data Records (EDRs). This paper provides an overview of Suomi NPP VIIRS on-orbit calibration activities and examples of sensor initial on-orbit performance. It focuses on the radiometric calibration support activities and capabilities provided by the NASA VCST.

  9. Two calibration procedures for a gyroscope-free inertial measurement system based on a double-pendulum apparatus

    Science.gov (United States)

    Cappa, P.; Patanè, F.; Rossi, S.

    2008-05-01

    This paper presents a novel calibration algorithm to be used with a gyro-free inertial measurement unit (GF-IMU) based on the use of linear accelerometers (AC). The analytical approach can be implemented in two calibration procedures. The first procedure (P-I) is articulated in the conduction of a static trial, to compute the sensitivity and the direction of the sensing axis of each AC, followed by a dynamic trial, to determine the AC locations. By contrast, the latter procedure (P-II) consists in the calculation of the previously indicated calibration parameters by means of a dynamic trial only. The feasibility of the two calibration procedures has been investigated by testing two GF-IMUs, equipped with ten and six bi-axial linear ACs, with an ad hoc instrumented double-pendulum apparatus. P-I and P-II were compared to a calibration procedure used as a reference (P-REF), which incorporates the AC positions measured with an optoelectronic system. The experimental results we present in this paper demonstrate that (i) P-I is able to determine the calibration parameters of the AC array with a higher accuracy than P-II; (ii) consequently, the errors associated with translational (a0 - g) and rotational (\\dot{\\bm \\omega }) acceleration components for the two GF-IMUs are significantly greater using P-II than P-I and (iii) the errors in (a0 - g) and \\dot{\\bm \\omega } obtained with P-I are comparable with the ones obtainable by using P-REF. Thus, the proposed novel algorithm used in P-I, in conjunction with the double-pendulum apparatus, can be globally considered a viable tool in GF-IMU calibration.

  10. Virtual and remote experiments for radiometric and photometric measurements

    International Nuclear Information System (INIS)

    Thoms, L-J; Girwidz, R

    2017-01-01

    The analysis of spectra is fundamental to our modern understanding of wave optics and colour perception. Since spectrometers are expensive, and accurate calibration is necessary to achieve high quality spectra, we developed a remote lab on optical spectrometry. With this tool, students can carry out real experiments over the Internet. In this article the pros and cons of remote labs, the physical background of optical spectrometry, and the development and use of a radiometric remote lab for higher education are discussed. The remote lab is freely accessible to everyone at http://virtualremotelab.net. (paper)

  11. Virtual and remote experiments for radiometric and photometric measurements

    Science.gov (United States)

    Thoms, L.-J.; Girwidz, R.

    2017-09-01

    The analysis of spectra is fundamental to our modern understanding of wave optics and colour perception. Since spectrometers are expensive, and accurate calibration is necessary to achieve high quality spectra, we developed a remote lab on optical spectrometry. With this tool, students can carry out real experiments over the Internet. In this article the pros and cons of remote labs, the physical background of optical spectrometry, and the development and use of a radiometric remote lab for higher education are discussed. The remote lab is freely accessible to everyone at http://virtualremotelab.net.

  12. The calibration procedures in the Studsvik standardized personnel dosimetry system

    International Nuclear Information System (INIS)

    Widell, C.O.

    1978-01-01

    Every large nuclear installation in Sweden reads its own personnel TLDs. In order to supervise this decentralized reading of dose meters, the TLD readers are connected by telephone lines to a central computer for dose registration. This computer is used both for registering the personnel doses and for checking the TLD readers. This checking is performed by the use of pre-irradiated calibration dose meters which are always used when a batch of personnel dose meters are read. The pre-irradiated dose meters are either irradiated using 137 Cs to various doses up to 100mSv(10000mrem) or using a 90 Sr source in a reference dose irradiator to a dose equal to 3mSv(300mrem) from a 137 Cs source. The results from the reading of the pre-irradiated dose meters are processed by the computer and a calibration factor is calculated. The calibration factor is automatically used to calculate the doses to the personnel TLD's. However, if the calibration factor deviates by more than 10% from the previously used factor, this fact is shown to the operator - who then has to decide what calibration factor is going to be used. This calibration and supervisory procedure together with the safety interlocks in the TLD readers has resulted in a very reliable and accurate dosimetry system. (author)

  13. Initial tank calibration at NUCEF critical facility. 1. Measurement procedure and its result

    International Nuclear Information System (INIS)

    Yanagisawa, Hiroshi; Mineo, Hideaki; Tonoike, Kotaro; Takeshita, Isao; Hoshi, Katsuya; Hagiwara, Hiroyuki.

    1994-07-01

    Initial tank calibrations were carried out prior to hot operation of critical facilities in NUCEF: Nuclear Fuel Cycle Safety Engineering Research Facility, for the purpose of the nuclear material accountancy and control for the facility. Raw calibration data were collected from single run per one tank by measuring differential pressure with dip-tube systems, weight of calibration liquid (demineralized water) poured into the tank, temperature in the tank and so on, without operation of tank ventilation system. Volume and level data were obtained by applying density and buoyancy corrections to the raw data. As a result, the evaluated measurement errors of volume and level were small enough, e.g. within 0.2 lit. and 1.0 mm, respectively, for Pu accountancy tanks. This paper summarizes the above-mentioned measurement procedures, collected data, data correction procedures and evaluated measurement errors. (author)

  14. Effects of pressurization procedures on calibration results for precise pressure transducers

    International Nuclear Information System (INIS)

    Kajikawa, Hiroaki; Kobata, Tokihiko

    2010-01-01

    The output of electromechanical pressure gauges depends on not only the currently applied pressure, but also the pressurization history. Thus, the calibration results of gauges are affected by the pressurization procedure. In this paper, among several important factors influencing the results, we report the effects of the interval between the calibration cycles and the effects of the preliminary pressurizations. In order to quantitatively evaluate these effects, we developed a fully automated system that uses a pressure balance to calibrate pressure gauges. Subsequently, gauges containing quartz Bourdon-type pressure transducers were calibrated in a stepwise manner for pressures between 10 MPa and 100 MPa. The typical standard deviation of the data over three cycles was reduced to a few parts per million (ppm). The interval between the calibration cycles, which ranges from zero to more than 12 h, exerts a strong influence on the results in the process of increasing the pressure, where at 10 MPa the maximum difference between the results was approximately 40 ppm. The preliminary pressurization immediately before the calibration cycle reduces the effects of the interval on the results in certain cases. However, in turn, the influence of the waiting time between the preliminary pressurization and the main calibration cycle becomes strong. In the present paper, we outline several possible measures for obtaining calibration results with high reproducibility

  15. The radiometric performances of the Planetary Fourier Spectrometer for Mars exploration

    Science.gov (United States)

    Palomba, E.; Colangeli, L.; Formisano, V.; Piccioni, G.; Cafaro, N.; Moroz, V.

    1999-04-01

    The Planetary Fourier Spectrometer (PFS) is a Fourier transform interferometer, operating in the range 1.2-45 μm. The instrument, previously included in the payload of the failed mission Mars ‧96, is proposed for the future space mission Mars Express, under study by ESA. The present paper is aimed at presenting the radiometric performances of PFS. The two channels (LW and SW) forming PFS were analysed and characterised in terms of sensitivity and noise equivalent brightness. To cover the wide spectral range of PFS, different blackbodies were used for calibration. The built-in blackbodies, needed for the in-flight calibrations, were also characterised. The results show that the LW channel is comparable with IRIS Mariner 9 in terms of noise equivalent brightness. The SW channel performances, while satisfactorily, could be improved by lowering the sensor operative temperature. A simple model of the Mars radiance is used in order to calculate the signal-to-noise ratio on the spectra in typical observation conditions. The computed signal-to-noise ratio for the LW channel varies between 430 and 40, while for the SW channel it ranges from 150 to 30. The radiometric analyses confirm that PFS performances are compliant with the design requirements of the instrument. PFS is fully validated for future remote exploration of the atmosphere and the surface of Mars.

  16. The simple procedure for the fluxgate magnetometers calibration

    Science.gov (United States)

    Marusenkov, Andriy

    2014-05-01

    The fluxgate magnetometers are widely used in geophysics investigations including the geomagnetic field monitoring at the global network of geomagnetic observatories as well as for electromagnetic sounding of the Earth's crust conductivity. For solving these tasks the magnetometers have to be calibrated with an appropriate level of accuracy. As a particular case, the ways to satisfy the recent requirements to the scaling and orientation errors of 1-second INTERNAGNET magnetometers are considered in the work. The goal of the present study was to choose a simple and reliable calibration method for estimation of scale factors and angular errors of the three-axis magnetometers in the field. There are a large number of the scalar calibration methods, which use a free rotation of the sensor in the calibration field followed by complicated data processing procedures for numerical solution of the high-order equations set. The chosen approach also exploits the Earth's magnetic field as a calibrating signal, but, in contrast to other methods, the sensor has to be oriented in some particular positions in respect to the total field vector, instead of the sensor free rotation. This allows to use very simple and straightforward linear computation formulas and, as a result, to achieve more reliable estimations of the calibrated parameters. The estimation of the scale factors is performed by the sequential aligning of each component of the sensor in two positions: parallel and anti-parallel to the Earth's magnetic field vector. The estimation of non-orthogonality angles between each pair of components is performed after sequential aligning of the components at the angles +/- 45 and +/- 135 degrees of arc in respect to the total field vector. Due to such four positions approach the estimations of the non-orthogonality angles are invariant to the zero offsets and non-linearity of transfer functions of the components. The experimental justifying of the proposed method by means of the

  17. Validation of the in-flight calibration procedures for the MICROSCOPE space mission

    Science.gov (United States)

    Hardy, Émilie; Levy, Agnès; Rodrigues, Manuel; Touboul, Pierre; Métris, Gilles

    2013-11-01

    The MICROSCOPE space mission aims to test the Equivalence Principle with an accuracy of 10-15. The drag-free micro-satellite will orbit around the Earth and embark a differential electrostatic accelerometer including two cylindrical test masses submitted to the same gravitational field and made of different materials. The experience consists in testing the equality of the electrostatic acceleration applied to the masses to maintain them relatively motionless. The accuracy of the measurements exploited for the test of the Equivalence Principle is limited by our a priori knowledge of several physical parameters of the instrument. These parameters are partially estimated on-ground, but with an insufficient accuracy, and an in-orbit calibration is therefore required to correct the measurements. The calibration procedures have been defined and their analytical performances have been evaluated. In addition, a simulator software including the dynamics model of the instrument, the satellite drag-free system and the perturbing environment has been developed to numerically validate the analytical results. After an overall presentation of the MICROSCOPE mission, this paper will describe the calibration procedures and focus on the simulator. Such an in-flight calibration is mandatory for similar space missions taking advantage of a drag-free system.

  18. Merging airborne and carborne radiometric data for surveying the Deir Az-Zor area, Syria

    International Nuclear Information System (INIS)

    Jubeli, Y.M.; Aissa, M.; Al-Hent, R.

    1997-01-01

    To complete the radiometric map of Syria, and to estimate the natural background radiation levels for environmental monitoring, a carborne survey was undertaken over the Deir Az-Zor area. This area was not covered by a previous airborne survey, except for peripheral regions in the south and west. To complete the radiometric map, results of the carborne and airborne surveys had to be merged. This paper presents the merging procedure which was used after normalizing the two data sets to match each other. No anomalies suitable for radioelement exploration were found. However, the overall radiometric maps resulting from the present work were consistent with the maps of the areas covered by the airborne survey. (author)

  19. SIR-C/X-SAR data calibration and ground truth campaign over the NASA-CB1 test-site

    International Nuclear Information System (INIS)

    Notarnicola, C.; Posa, F.; Refice, A.; Sergi, R.; Smacchia, P.; Casarano, D.; De Carolis, G.; Mattia, F.; Schena, V.D.

    2001-01-01

    During the Space Shuttle Endeavour mission in October 1994, a remote-sensing campaign was carried out with the objectives of both radiometric and polarimetric calibration and ground truth data acquisition of bare soils. This paper presents the results obtained in the experiment. Polarimetric cross-talk and channel imbalance values, as well as radiometric calibration parameters, have been found to be within the science requirements for SAR images. Regarding ground truth measurements, a wide spread in the height rms values and correlation lengths has been observed, which was motivated a critical revisiting of surface parameters descriptors

  20. Invited Article: Deep Impact instrument calibration.

    Science.gov (United States)

    Klaasen, Kenneth P; A'Hearn, Michael F; Baca, Michael; Delamere, Alan; Desnoyer, Mark; Farnham, Tony; Groussin, Olivier; Hampton, Donald; Ipatov, Sergei; Li, Jianyang; Lisse, Carey; Mastrodemos, Nickolaos; McLaughlin, Stephanie; Sunshine, Jessica; Thomas, Peter; Wellnitz, Dennis

    2008-09-01

    Calibration of NASA's Deep Impact spacecraft instruments allows reliable scientific interpretation of the images and spectra returned from comet Tempel 1. Calibrations of the four onboard remote sensing imaging instruments have been performed in the areas of geometric calibration, spatial resolution, spectral resolution, and radiometric response. Error sources such as noise (random, coherent, encoding, data compression), detector readout artifacts, scattered light, and radiation interactions have been quantified. The point spread functions (PSFs) of the medium resolution instrument and its twin impactor targeting sensor are near the theoretical minimum [ approximately 1.7 pixels full width at half maximum (FWHM)]. However, the high resolution instrument camera was found to be out of focus with a PSF FWHM of approximately 9 pixels. The charge coupled device (CCD) read noise is approximately 1 DN. Electrical cross-talk between the CCD detector quadrants is correctable to <2 DN. The IR spectrometer response nonlinearity is correctable to approximately 1%. Spectrometer read noise is approximately 2 DN. The variation in zero-exposure signal level with time and spectrometer temperature is not fully characterized; currently corrections are good to approximately 10 DN at best. Wavelength mapping onto the detector is known within 1 pixel; spectral lines have a FWHM of approximately 2 pixels. About 1% of the IR detector pixels behave badly and remain uncalibrated. The spectrometer exhibits a faint ghost image from reflection off a beamsplitter. Instrument absolute radiometric calibration accuracies were determined generally to <10% using star imaging. Flat-field calibration reduces pixel-to-pixel response differences to approximately 0.5% for the cameras and <2% for the spectrometer. A standard calibration image processing pipeline is used to produce archival image files for analysis by researchers.

  1. Invited Article: Deep Impact instrument calibration

    International Nuclear Information System (INIS)

    Klaasen, Kenneth P.; Mastrodemos, Nickolaos; A'Hearn, Michael F.; Farnham, Tony; Groussin, Olivier; Ipatov, Sergei; Li Jianyang; McLaughlin, Stephanie; Sunshine, Jessica; Wellnitz, Dennis; Baca, Michael; Delamere, Alan; Desnoyer, Mark; Thomas, Peter; Hampton, Donald; Lisse, Carey

    2008-01-01

    Calibration of NASA's Deep Impact spacecraft instruments allows reliable scientific interpretation of the images and spectra returned from comet Tempel 1. Calibrations of the four onboard remote sensing imaging instruments have been performed in the areas of geometric calibration, spatial resolution, spectral resolution, and radiometric response. Error sources such as noise (random, coherent, encoding, data compression), detector readout artifacts, scattered light, and radiation interactions have been quantified. The point spread functions (PSFs) of the medium resolution instrument and its twin impactor targeting sensor are near the theoretical minimum [∼1.7 pixels full width at half maximum (FWHM)]. However, the high resolution instrument camera was found to be out of focus with a PSF FWHM of ∼9 pixels. The charge coupled device (CCD) read noise is ∼1 DN. Electrical cross-talk between the CCD detector quadrants is correctable to <2 DN. The IR spectrometer response nonlinearity is correctable to ∼1%. Spectrometer read noise is ∼2 DN. The variation in zero-exposure signal level with time and spectrometer temperature is not fully characterized; currently corrections are good to ∼10 DN at best. Wavelength mapping onto the detector is known within 1 pixel; spectral lines have a FWHM of ∼2 pixels. About 1% of the IR detector pixels behave badly and remain uncalibrated. The spectrometer exhibits a faint ghost image from reflection off a beamsplitter. Instrument absolute radiometric calibration accuracies were determined generally to <10% using star imaging. Flat-field calibration reduces pixel-to-pixel response differences to ∼0.5% for the cameras and <2% for the spectrometer. A standard calibration image processing pipeline is used to produce archival image files for analysis by researchers.

  2. Generalized Calibration of the Polarimetric Albedo Scale of Asteroids

    Science.gov (United States)

    Lupishko, D. F.

    2018-03-01

    Six different calibrations of the polarimetric albedo scale of asteroids have been published so far. Each of them contains its particular random and systematic errors and yields its values of geometric albedo. On the one hand, this complicates their analysis and comparison; on the other hand, it becomes more and more difficult to decide which of the proposed calibrations should be used. Moreover, in recent years, new databases on the albedo of asteroids obtained from the radiometric surveys of the sky with the orbital space facilities (the InfraRed Astronomical Satellite (IRAS), the Japanese astronomical satellite AKARI (which means "light"), the Wide-field Infrared Survey Explorer (WISE), and the Near-Earth Object Wide-field Survey Explorer (NEOWISE)) have appeared; and the database on the diameters and albedos of asteroids obtained from their occultations of stars has substantially increased. Here, we critically review the currently available calibrations and propose a new generalized calibration derived from the interrelations between the slope h and the albedo and between P min and the albedo. This calibration is based on all of the available series of the asteroid albedos and the most complete data on the polarization parameters of asteroids. The generalized calibration yields the values of the polarimetric albedo of asteroids in the system unified with the radiometric albedos and the albedos obtained from occultations of stars by asteroids. This, in turn, removes the difficulties in their comparison, joint analysis, etc.

  3. Radiometric installations for automatic control of industrial processes and some possibilities of the specialized computers application

    International Nuclear Information System (INIS)

    Kuzino, S.; Shandru, P.

    1979-01-01

    It is noted that application of radioisotope devices in circuits for automation of some industrial processes permits to obtain the on-line information about some parameters of these processes. This information being passed to a computer, controlling the process, permits to obtain and maintain some optimum technological perameters of this process. Some elements of the automation stem projecting are given from the poin of wiev of the radiometric devices tuning, calibration of the radiometric devices with the purpose to get a digital answer in the on-line regime with the preset accuracy and thrustworthyness levels for supplying them to the controlling computer; determination of the system's reaction on the base of the preset statistical criteria; development, on the base of the data obtained from the computer, of an algorithm for the functional checking of radiometric devices' characteristics, - stability and reproductibility of readings in the operation regime as well as determination of the value threshold of an answer, depending on the measured parameter [ru

  4. CALIPSO lidar calibration at 532 nm: version 4 nighttime algorithm

    Science.gov (United States)

    Kar, Jayanta; Vaughan, Mark A.; Lee, Kam-Pui; Tackett, Jason L.; Avery, Melody A.; Garnier, Anne; Getzewich, Brian J.; Hunt, William H.; Josset, Damien; Liu, Zhaoyan; Lucker, Patricia L.; Magill, Brian; Omar, Ali H.; Pelon, Jacques; Rogers, Raymond R.; Toth, Travis D.; Trepte, Charles R.; Vernier, Jean-Paul; Winker, David M.; Young, Stuart A.

    2018-03-01

    Data products from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) were recently updated following the implementation of new (version 4) calibration algorithms for all of the Level 1 attenuated backscatter measurements. In this work we present the motivation for and the implementation of the version 4 nighttime 532 nm parallel channel calibration. The nighttime 532 nm calibration is the most fundamental calibration of CALIOP data, since all of CALIOP's other radiometric calibration procedures - i.e., the 532 nm daytime calibration and the 1064 nm calibrations during both nighttime and daytime - depend either directly or indirectly on the 532 nm nighttime calibration. The accuracy of the 532 nm nighttime calibration has been significantly improved by raising the molecular normalization altitude from 30-34 km to the upper possible signal acquisition range of 36-39 km to substantially reduce stratospheric aerosol contamination. Due to the greatly reduced molecular number density and consequently reduced signal-to-noise ratio (SNR) at these higher altitudes, the signal is now averaged over a larger number of samples using data from multiple adjacent granules. Additionally, an enhanced strategy for filtering the radiation-induced noise from high-energy particles was adopted. Further, the meteorological model used in the earlier versions has been replaced by the improved Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2), model. An aerosol scattering ratio of 1.01 ± 0.01 is now explicitly used for the calibration altitude. These modifications lead to globally revised calibration coefficients which are, on average, 2-3 % lower than in previous data releases. Further, the new calibration procedure is shown to eliminate biases at high altitudes that were present in earlier versions and consequently leads to an improved representation of

  5. Transportable high sensitivity small sample radiometric calorimeter

    International Nuclear Information System (INIS)

    Wetzel, J.R.; Biddle, R.S.; Cordova, B.S.; Sampson, T.E.; Dye, H.R.; McDow, J.G.

    1998-01-01

    A new small-sample, high-sensitivity transportable radiometric calorimeter, which can be operated in different modes, contains an electrical calibration method, and can be used to develop secondary standards, will be described in this presentation. The data taken from preliminary tests will be presented to indicate the precision and accuracy of the instrument. The calorimeter and temperature-controlled bath, at present, require only a 30-in. by 20-in. tabletop area. The calorimeter is operated from a laptop computer system using unique measurement module capable of monitoring all necessary calorimeter signals. The calorimeter can be operated in the normal calorimeter equilibration mode, as a comparison instrument, using twin chambers and an external electrical calibration method. The sample chamber is 0.75 in (1.9 cm) in diameter by 2.5 in. (6.35 cm) long. This size will accommodate most 238 Pu heat standards manufactured in the past. The power range runs from 0.001 W to <20 W. The high end is only limited by sample size

  6. Establishment of a procedure to calculate the measurement uncertainties in radiation survey meters calibration

    International Nuclear Information System (INIS)

    Manzoli, J.E.; Potiens, M.P.A.

    2000-01-01

    The Calibration Laboratory of Sao Paulo calibrates more than one thousand gamma ray survey meters a year; beside other kinds of radiotherapy, radiodiagnostic and radiation protection instruments. It has a standard (600 cm 3 ) cylinder ionization chamber (Nuclear Enterprises Ltd. model 2511/3) traceable to the Brazilian Secondary Standard Dosimetry Laboratory (SSDL) whose instruments are traceable to the BIPM. Annually the beam dosimetry is performed using this chamber and the results are used as the true values for calibration purposes. The uncertainties present in every direct or indirect measurement during the calibration procedure must be evaluated for purposes of laboratory quality control. All calculation steps in the propagation of errors are presented in this work staging from the ionization chamber charge measured with the standard instrument. Such a propagation was made in space and time, considering even the environmental quantities uncertainties. The propagation was necessary in space, because the ionization chamber measurements were performed at only one space position. The time propagation was essential due to the fact that the activity is a peculiar physical quantity which changes with time according to precise relations for a specific radionuclide. The clear indication of every measurement uncertainty is always important to quantify the quality of this measurement. Nowadays the achievement of calibration laboratory quality systems requires the expression of all uncertainties and the procedure used to evaluate it. An example of this procedure in the case of the calibration of a typical portable radiation survey meter is presented. The direct exposure rate instrument measurement was compared with the true value given by the standard instrument properly propagated and all quantities used have their uncertainties shown. (author)

  7. Technical Note: Procedure for the calibration and validation of kilo-voltage cone-beam CT models

    Energy Technology Data Exchange (ETDEWEB)

    Vilches-Freixas, Gloria; Létang, Jean Michel; Rit, Simon, E-mail: simon.rit@creatis.insa-lyon.fr [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1206, INSA-Lyon, Université Lyon 1, Centre Léon Bérard, Lyon 69373 Cedex 08 (France); Brousmiche, Sébastien [Ion Beam Application, Louvain-la-Neuve 1348 (Belgium); Romero, Edward; Vila Oliva, Marc [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1206, INSA-Lyon, Université Lyon 1, Centre Léon Bérard, Lyon 69373 Cedex 08, France and Ion Beam Application, Louvain-la-Neuve 1348 (Belgium); Kellner, Daniel; Deutschmann, Heinz; Keuschnigg, Peter; Steininger, Philipp [Institute for Research and Development on Advanced Radiation Technologies, Paracelsus Medical University, Salzburg 5020 (Austria)

    2016-09-15

    Purpose: The aim of this work is to propose a general and simple procedure for the calibration and validation of kilo-voltage cone-beam CT (kV CBCT) models against experimental data. Methods: The calibration and validation of the CT model is a two-step procedure: the source model then the detector model. The source is described by the direction dependent photon energy spectrum at each voltage while the detector is described by the pixel intensity value as a function of the direction and the energy of incident photons. The measurements for the source consist of a series of dose measurements in air performed at each voltage with varying filter thicknesses and materials in front of the x-ray tube. The measurements for the detector are acquisitions of projection images using the same filters and several tube voltages. The proposed procedure has been applied to calibrate and assess the accuracy of simple models of the source and the detector of three commercial kV CBCT units. If the CBCT system models had been calibrated differently, the current procedure would have been exclusively used to validate the models. Several high-purity attenuation filters of aluminum, copper, and silver combined with a dosimeter which is sensitive to the range of voltages of interest were used. A sensitivity analysis of the model has also been conducted for each parameter of the source and the detector models. Results: Average deviations between experimental and theoretical dose values are below 1.5% after calibration for the three x-ray sources. The predicted energy deposited in the detector agrees with experimental data within 4% for all imaging systems. Conclusions: The authors developed and applied an experimental procedure to calibrate and validate any model of the source and the detector of a CBCT unit. The present protocol has been successfully applied to three x-ray imaging systems. The minimum requirements in terms of material and equipment would make its implementation suitable in

  8. Radiometric enrichment of nonradioactive ores

    International Nuclear Information System (INIS)

    Mokrousov, V.A.; Lileev, V.A.

    1979-01-01

    Considered are the methods of mineral enrichment based on the use of the radioation of various types. The physical essence of enrichment processes is presented, their classification is given. Described are the ore properties influencing the efficiency of radiometric enrichment, methods of the properties study and estimation of ore enrichment. New possibilities opened by radiometric enrichment in the technology of primary processing of mineral raw materials are elucidated. A considerable attention is paid to the main and auxiliary equipment for radiometric enrichment. The foundations of the safety engineering are presented in a brief form. Presented are also results of investigations and practical works in the field of enrichment of ores of non-ferrous, ferrous and non-metallic minerals with the help of radiometric methods

  9. Radiometric Performance of the TerraSAR-X Mission over More Than Ten Years of Operation

    Directory of Open Access Journals (Sweden)

    Marco Schwerdt

    2018-05-01

    Full Text Available The TerraSAR-X mission, based on two satellites, has produced SAR data products of high quality for a number of scientific and commercial applications for more than ten years. To guarantee the stability and the reliability of these highly accurate SAR data products, both systems were first accurately calibrated during their respective commissioning phases and have been permanently monitored since then. Based on a short description of the methods applied, this paper focuses on the radiometric performance including the gain and phase properties of the transmit/receiver modules, the antenna pattern checked by evaluating scenes acquired over uniformly distributed targets and the radiometric stability derived from permanently deployed point targets. The outcome demonstrates the remarkable performance of both systems since their respective launch.

  10. Traceable calibration of photovoltaic reference cells using natural sunlight

    Science.gov (United States)

    Müllejans, H.; Zaaiman, W.; Pavanello, D.; Dunlop, E. D.

    2018-02-01

    At the European Solar Test Installation (ESTI) photovoltaic (PV) reference cells are calibrated traceably to SI units via the World Radiometric Reference (WRR) using natural sunlight. The Direct Sunlight Method (DSM) is described in detail and the latest measurement results and an updated uncertainty budget are reported. These PV reference cells then provide a practical means for measuring the irradiance of natural or simulated sunlight during the calibration of other PV devices.

  11. Determination of degree of compacting and of moisture content by radiometric probes

    International Nuclear Information System (INIS)

    Martinec, J.; Paul, P.

    1977-01-01

    A survey is given of radiometric probes used for measuring bulk density and moisture content. Surface probes are used in depths of up to 20 cm with an accuracy of 10%, drive-in probes are used to depths of up to 50 cm with a 4% error, depth probes are used for measuring in depths of 30 to 50 cm with an accuracy of roughly 5% and bulk density in depths of 10 to 150 cm may be measured with an accuracy of 2% using a lysimeter. Changes in the bulk density and soil moisture of the subsoil of an airport runway were studied radiometrically in dependence on time and depth. The dependence is represented graphically. The results of radiometric measurements were compared with the conventional method using a lysimeter probe; the comparison showed that the results were lower by about 7% for the moisture content and higher by about 8% for the bulk density. Radiometric measurements for determining bulk density and soil moisture are advantageous in that they allow the measurement of a great number of sites without any major disturbance of the measured material and results are available immediately on measurement. The economic effect is significant in a large number of measurements carried out on a surface having the same chemical composition and similar grain size which does not necessitate calibration of the instruments to be made more than once a week. The NZK-201 probe by Tesla does not provide sufficiently accurate information on the moisture and density of the earths probed

  12. Contributed Review: Absolute spectral radiance calibration of fiber-optic shock-temperature pyrometers using a coiled-coil irradiance standard lamp

    Energy Technology Data Exchange (ETDEWEB)

    Fat’yanov, O. V., E-mail: fatyan1@gps.caltech.edu; Asimow, P. D., E-mail: asimow@gps.caltech.edu [Division of Geological and Planetary Sciences 252-21, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-10-15

    We describe an accurate and precise calibration procedure for multichannel optical pyrometers such as the 6-channel, 3-ns temporal resolution instrument used in the Caltech experimental geophysics laboratory. We begin with a review of calibration sources for shock temperatures in the 3000-30 000 K range. High-power, coiled tungsten halogen standards of spectral irradiance appear to be the only practical alternative to NIST-traceable tungsten ribbon lamps, which are no longer available with large enough calibrated area. However, non-uniform radiance complicates the use of such coiled lamps for reliable and reproducible calibration of pyrometers that employ imaging or relay optics. Careful analysis of documented methods of shock pyrometer calibration to coiled irradiance standard lamps shows that only one technique, not directly applicable in our case, is free of major radiometric errors. We provide a detailed description of the modified Caltech pyrometer instrument and a procedure for its absolute spectral radiance calibration, accurate to ±5%. We employ a designated central area of a 0.7× demagnified image of a coiled-coil tungsten halogen lamp filament, cross-calibrated against a NIST-traceable tungsten ribbon lamp. We give the results of the cross-calibration along with descriptions of the optical arrangement, data acquisition, and processing. We describe a procedure to characterize the difference between the static and dynamic response of amplified photodetectors, allowing time-dependent photodiode correction factors for spectral radiance histories from shock experiments. We validate correct operation of the modified Caltech pyrometer with actual shock temperature experiments on single-crystal NaCl and MgO and obtain very good agreement with the literature data for these substances. We conclude with a summary of the most essential requirements for error-free calibration of a fiber-optic shock-temperature pyrometer using a high-power coiled tungsten halogen

  13. Calibration procedures of the Tore-Supra infrared endoscopes

    Science.gov (United States)

    Desgranges, C.; Jouve, M.; Balorin, C.; Reichle, R.; Firdaouss, M.; Lipa, M.; Chantant, M.; Gardarein, J. L.; Saille, A.; Loarer, T.

    2018-01-01

    Five endoscopes equipped with infrared cameras working in the medium infrared range (3-5 μm) are installed on the controlled thermonuclear fusion research device Tore-Supra. These endoscopes aim at monitoring the plasma facing components surface temperature to prevent their overheating. Signals delivered by infrared cameras through endoscopes are analysed and used on the one hand through a real time feedback control loop acting on the heating systems of the plasma to decrease plasma facing components surface temperatures when necessary, on the other hand for physics studies such as determination of the incoming heat flux . To ensure these two roles a very accurate knowledge of the absolute surface temperatures is mandatory. Consequently the infrared endoscopes must be calibrated through a very careful procedure. This means determining their transmission coefficients which is a delicate operation. Methods to calibrate infrared endoscopes during the shutdown period of the Tore-Supra machine will be presented. As they do not allow determining the possible transmittances evolution during operation an in-situ method is presented. It permits the validation of the calibration performed in laboratory as well as the monitoring of their evolution during machine operation. This is possible by the use of the endoscope shutter and a dedicated plasma scenario developed to heat it. Possible improvements of this method are briefly evoked.

  14. Accurate antenna reflector loss measurements for radiometer calibration budget

    DEFF Research Database (Denmark)

    Skou, Niels

    1996-01-01

    Antenna reflector losses may play an important role in the calibration budget for a microwave radiometer. If the losses are small they are difficult to measure by traditional means. However, they can be assessed directly by radiometric means using the sky brightness temperature as incident...

  15. HYDICE postflight data processing

    Science.gov (United States)

    Aldrich, William S.; Kappus, Mary E.; Resmini, Ronald G.; Mitchell, Peter A.

    1996-06-01

    The hyperspectral digital imagery collection experiment (HYDICE) sensor records instrument counts for scene data, in-flight spectral and radiometric calibration sequences, and dark current levels onto an AMPEX DCRsi data tape. Following flight, the HYDICE ground data processing subsystem (GDPS) transforms selected scene data from digital numbers (DN) to calibrated radiance levels at the sensor aperture. This processing includes: dark current correction, spectral and radiometric calibration, conversion to radiance, and replacement of bad detector elements. A description of the algorithms for post-flight data processing is presented. A brief analysis of the original radiometric calibration procedure is given, along with a description of the development of the modified procedure currently used. Example data collected during the 1995 flight season, but uncorrected and processed, are shown to demonstrate the removal of apparent sensor artifacts (e.g., non-uniformities in detector response over the array) as a result of this transformation.

  16. Comprehensive Calibration and Validation Site for Information Remote Sensing

    Science.gov (United States)

    Li, C. R.; Tang, L. L.; Ma, L. L.; Zhou, Y. S.; Gao, C. X.; Wang, N.; Li, X. H.; Wang, X. H.; Zhu, X. H.

    2015-04-01

    As a naturally part of information technology, Remote Sensing (RS) is strongly required to provide very precise and accurate information product to serve industry, academy and the public at this information economic era. To meet the needs of high quality RS product, building a fully functional and advanced calibration system, including measuring instruments, measuring approaches and target site become extremely important. Supported by MOST of China via national plan, great progress has been made to construct a comprehensive calibration and validation (Cal&Val) site, which integrates most functions of RS sensor aviation testing, EO satellite on-orbit caration and performance assessment and RS product validation at this site located in Baotou, 600km west of Beijing. The site is equipped with various artificial standard targets, including portable and permanent targets, which supports for long-term calibration and validation. A number of fine-designed ground measuring instruments and airborne standard sensors are developed for realizing high-accuracy stepwise validation, an approach in avoiding or reducing uncertainties caused from nonsynchronized measurement. As part of contribution to worldwide Cal&Val study coordinated by CEOS-WGCV, Baotou site is offering its support to Radiometric Calibration Network of Automated Instruments (RadCalNet), with an aim of providing demonstrated global standard automated radiometric calibration service in cooperation with ESA, NASA, CNES and NPL. Furthermore, several Cal&Val campaigns have been performed during the past years to calibrate and validate the spaceborne/airborne optical and SAR sensors, and the results of some typical demonstration are discussed in this study.

  17. Rapid procedure to calibrate EC-10 and EC-20 capacitance sensors ...

    African Journals Online (AJOL)

    A rapid calibration procedure for EC-10 and EC-20 sensors is introduced to promote the commercial use of these sensors for hydroponic irrigation management in coir. The method is comprised of taking one sensor reading, by a sensor installed under hydroponic crop production conditions, and one gravimetric sample, ...

  18. Primary calibration of TXRF in comparison with the standard droplet procedure

    International Nuclear Information System (INIS)

    Dobler, M.; Reus, U.; Knoth, J.; Schwenke, H.

    2000-01-01

    For the determination of contamination on wafer surfaces with total reflection x-ray fluorescence spectrometry (TXRF) normally external 1 ng Ni droplet standards were used for calibration. This method is based on several assumptions about the properties of the standard droplet which are strongly affected by the preparation of the samples. In this paper a study is resented which compares the external droplet method with a calibration procedure using the fundamental physical background of total reflection x-ray fluorescence spectrometry and the properties of Ni bulk material. The particular features of the two methods will be discussed and the obtained results compared to each other. It is demonstrated in this study that the calibration with Ni bulk material is a primary method which offers several advantages compared to the calibration based on droplet standards. These advantages are unique and enable a more reliable and reproducible quantification of contamination on wafer surfaces. This is caused by the fact that the method is standardless and only based on fundamental parameters and natural constants. It is also demonstrated that effects which could be caused by especial features of the measured samples (particle or film, e.g.) or by the degradation of the calibration sample could be excluded. (author)

  19. Offline calibration procedure of the CMS Drift Tube detectors

    International Nuclear Information System (INIS)

    Abbiendi, G; Battilana, C; Cavallo, F R; Giunta, M; Guiducci, L; Amapane, N; Bolognesi, S; Cerminara, G; Bellan, R; Biallass, P; Frangenheim, J; Biasotto, M; Tazon, A Calderon; Cepeda, M; Cruz, B De La; Pardos, C Diez; Bedoya, C Fernandez; Iglesias, M C Fouz; Menendez, J Fernandez; Gresele, A

    2009-01-01

    The barrel region of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider is instrumented with Drift Tube (DT) detectors. This paper describes in full details the calibration of the DT hit reconstruction algorithm. After inter-channel synchronization has been verified through the appropriate hardware procedure, the time pedestals are extracted directly from the distribution of the recorded times. Further corrections for time-of-flight and time of signal propagation are applied as soon as the three-dimensional hit position within the DT chamber is known. The different effects of the time pedestal miscalibration on the two main hit reconstruction algorithms are shown. The drift velocity calibration algorithm is based on the meantimer technique. Different meantimer relations for different track angles and patterns of hit cells are used. This algorithm can also be used to determine the uncertainty on the reconstructed hit position.

  20. Impacts of the Angular Dependence of the Solar Diffuser BRDF Degradation Factor on the SNPP VIIRS Reflective Solar Band On-Orbit Radiometric Calibration

    Science.gov (United States)

    Lei, Ning; Xiong, Xiaoxiong

    2016-01-01

    Using an onboard sunlit solar diffuser (SD) as the primary radiance source, the visible infrared imaging radiometer suite (VIIRS) on the Suomi National Polar-orbiting Partnership satellite regularly performs radiometric calibration of its reflective solar bands (RSBs). The SD bidirectional reflectance distribution function (BRDF) value decreases over time. A numerical degradation factor is used to quantify the degradation and is determined by an onboard SD stability monitor (SDSM), which observes the sun and the sunlit SD at almost the same time. We had shown previously that the BRDF degradation factor was angle-dependent. Consequently, due to that the SDSM and the RSB view the SD at very different angles relative to both the solar and the SD surface normal vectors, directly applying the BRDF degradation factor determined by the SDSM to the VIIRS RSB calibration can result in large systematic errors. We develop a phenomenological model to calculate the BRDF degradation factor for the RSB SD view from the degradation factor for the SDSM SD view. Using the yearly undulations observed in the VIIRS detector gains for the M1-M4 bands calculated with the SD BRDF degradation factor for the SDSM SD view and the difference between the VIIRS detector gains calculated from the SD and the lunar observations, we obtain the model parameter values and thus establish the relation between the BRDF degradation factors for the RSB and the SDSM SD view directions.

  1. Measurement of small antenna reflector losses for radiometer calibration budget

    DEFF Research Database (Denmark)

    Skou, Niels

    1997-01-01

    Antenna reflector losses play an important role in the calibration budget for a microwave radiometer. If the losses are small, they are difficult to measure by traditional means. However, they can be assessed directly by radiometric means using the sky brightness temperature as incident radiation...

  2. IAEA workshop/seminar on calibration procedures in dosimetry, Quito, 6-24 October 1986

    International Nuclear Information System (INIS)

    1987-01-01

    The International Atomic Energy Agency in co-operation with the Ecuadorian Atomic Energy Commission organized a workshop and seminar on calibration procedures in dosimetry at the SSDL Quito, 6 to 24 October 1986. All calibration laboratories in the Latin American region were invited to participate. The purpose of the workshop were calibration exercises with therapy-level and protection-level secondary standards at various calibration qualities, discussions on progress made in the different SSDLs in the region and delivering lectures on pertinent subjects. A total of 15 Secondary Standards (10 therapy-level and 5 protection-level) were brought along by the participants and 35 calibration comparisons were performed with those having a valid calibration factor. Thirty-three determinations of calibration factors were performed for secondary standards not having had a calibration before. Twelve different calibration qualities were available (Cobalt-60 and X-rays) and Agency's Secondary Standards traceable to BIPM were the reference standards. The participants were divided into two working groups, each one week and each group into two sub-groups. Both irradiation bunkers were used simultaneously. The one houses the teletherapy Cobalt-60 unit and the protection-level Cobalt-60 irradiator, the other one the constant potential X-ray machine with maximum generating potential of 320 KV and suitable for both therapy-level as well as protection-level calibrations. Due to the heavy workload and limited time available some nightshifts were required to accomplish the requested calibration comparisons

  3. Calibration in atomic spectrometry: A tutorial review dealing with quality criteria, weighting procedures and possible curvatures

    International Nuclear Information System (INIS)

    Mermet, Jean-Michel

    2010-01-01

    Calibration is required to obtain analyte concentrations in atomic spectrometry. To take full benefit of it, the adequacy of the coefficient of determination r 2 is discussed, and its use is compared with the uncertainty due to the prediction bands of the regression. Also discussed from a tutorial point of view are the influence of the weighting procedure and of different weighting factors, and the comparison between linear and quadratic regression to cope with curvatures. They are illustrated with examples based on the use of ICP-AES with nebulization and laser ablation, and of LIBS. Use of a calibration graph over several orders of magnitude may be problematic as well as the use of a quadratic regression to cope with possible curvatures. Instrument softwares that allow reprocessing of the calibration by selecting standards around the expected analyte concentration are convenient for optimizing the calibration procedure.

  4. Sterility test by radiometric technique

    International Nuclear Information System (INIS)

    Faruq, Muhammad

    1980-01-01

    Sterility test of pharmaceuticals can be carried out by the application of pharmacopoeia and radiometric technique. In Indonesia the application of pharmacopoeia technique is carried out through liquid germination for aerobacteria and for fungus and yeast. Radiometric technique is applied to autotrop and heterotrop bacteria. (SMN)

  5. New age radiometric ore sorting - the elegant solution

    International Nuclear Information System (INIS)

    Gordon, H.P.; Heuer, T.

    2000-01-01

    Radiometric ore sorting technology and application are described in two parts. Part I reviews the history of radiometric sorting in the minerals industry and describes the latest developments in radiometric sorting technology. Part II describes the history, feasibility study and approach used in the application of the new technology at Rossing Uranium Limited. There has been little progress in the field of radiometric sorting since the late 1970s. This has changed with the development of a high capacity radiometric sorter designed to operate on low-grade ore in the +75mm / -300mm size fraction. This has been designed specifically for an application at Rossing. Rossing has a long history in radiometric sorting dating back to 1968 when initial tests were conducted on the Rossing prospect. Past feasibility studies concluded that radiometric sorting would not conclusively reduce the unit cost of production unless sorting was used to increase production levels. The current feasibility study shows that the application of new radiometric sorter technology makes sorting viable without increasing production, and significantly more attractive with increased production. A pilot approach to confirm sorter performance is described. (author)

  6. The use of radiometric-logging techniques to determine uranium grade in certain mineralised Karoo boreholes

    International Nuclear Information System (INIS)

    Corner, B.; De Beer, G.P.

    1976-05-01

    During the period September-October 1975, 22 mineralised boreholes in nine different Karoo uranium occurrences were logged radiometrically with the aim of determining to what accuracy the actual uranium grade could be predicted from the gamma logs. The true uranium grades of the mineralised zones logged were known from existing chemical analyses. The results showed that the uranium grades could be predicted to an accuracy of better than 10% through the use of gamma-logging equipment calibrated at Pelindaba, provided that the ore was in equilibrium and that little or no thorium was present. Disequilibrium is, however, prevalent in the Karoo, and in the holes logged it occurred by depletion of uranium relative to its gamma-emitting daughter products. Such effects were mostly confined to the zone above the water table, and it is concluded that for Karoo-type occurrences, the high radiometric background levels observed over extended distances in some boreholes were indicative of radon-gas buildup, and hence of disequilibrium. It is further concluded that radiometric borehole logging can largely replace chemical analyses in the determination of uranium grade for ore-reserve calculations, although chemical checks for disequilibrium would always be necessary [af

  7. Direct Reflectance Measurements from Drones: Sensor Absolute Radiometric Calibration and System Tests for Forest Reflectance Characterization

    Science.gov (United States)

    Hakala, Teemu; Scott, Barry; Theocharous, Theo; Näsi, Roope; Suomalainen, Juha; Greenwell, Claire; Fox, Nigel

    2018-01-01

    Drone-based remote sensing has evolved rapidly in recent years. Miniaturized hyperspectral imaging sensors are becoming more common as they provide more abundant information of the object compared to traditional cameras. Reflectance is a physically defined object property and therefore often preferred output of the remote sensing data capture to be used in the further processes. Absolute calibration of the sensor provides a possibility for physical modelling of the imaging process and enables efficient procedures for reflectance correction. Our objective is to develop a method for direct reflectance measurements for drone-based remote sensing. It is based on an imaging spectrometer and irradiance spectrometer. This approach is highly attractive for many practical applications as it does not require in situ reflectance panels for converting the sensor radiance to ground reflectance factors. We performed SI-traceable spectral and radiance calibration of a tuneable Fabry-Pérot Interferometer -based (FPI) hyperspectral camera at the National Physical Laboratory NPL (Teddington, UK). The camera represents novel technology by collecting 2D format hyperspectral image cubes using time sequential spectral scanning principle. The radiance accuracy of different channels varied between ±4% when evaluated using independent test data, and linearity of the camera response was on average 0.9994. The spectral response calibration showed side peaks on several channels that were due to the multiple orders of interference of the FPI. The drone-based direct reflectance measurement system showed promising results with imagery collected over Wytham Forest (Oxford, UK). PMID:29751560

  8. Direct Reflectance Measurements from Drones: Sensor Absolute Radiometric Calibration and System Tests for Forest Reflectance Characterization.

    Science.gov (United States)

    Hakala, Teemu; Markelin, Lauri; Honkavaara, Eija; Scott, Barry; Theocharous, Theo; Nevalainen, Olli; Näsi, Roope; Suomalainen, Juha; Viljanen, Niko; Greenwell, Claire; Fox, Nigel

    2018-05-03

    Drone-based remote sensing has evolved rapidly in recent years. Miniaturized hyperspectral imaging sensors are becoming more common as they provide more abundant information of the object compared to traditional cameras. Reflectance is a physically defined object property and therefore often preferred output of the remote sensing data capture to be used in the further processes. Absolute calibration of the sensor provides a possibility for physical modelling of the imaging process and enables efficient procedures for reflectance correction. Our objective is to develop a method for direct reflectance measurements for drone-based remote sensing. It is based on an imaging spectrometer and irradiance spectrometer. This approach is highly attractive for many practical applications as it does not require in situ reflectance panels for converting the sensor radiance to ground reflectance factors. We performed SI-traceable spectral and radiance calibration of a tuneable Fabry-Pérot Interferometer -based (FPI) hyperspectral camera at the National Physical Laboratory NPL (Teddington, UK). The camera represents novel technology by collecting 2D format hyperspectral image cubes using time sequential spectral scanning principle. The radiance accuracy of different channels varied between ±4% when evaluated using independent test data, and linearity of the camera response was on average 0.9994. The spectral response calibration showed side peaks on several channels that were due to the multiple orders of interference of the FPI. The drone-based direct reflectance measurement system showed promising results with imagery collected over Wytham Forest (Oxford, UK).

  9. Comparison of the Thermal Response of Two Calorimetric Cells Dedicated to Nuclear Heating Measurements during Calibration

    International Nuclear Information System (INIS)

    Brun, J.; Reynard, C.; De-Vita, C.; Carette, M.; Muraglia, M.; Lyoussi, A.; Fourmentel, D.; Guimbal, P.; Villard, J-F.

    2013-06-01

    Nuclear heating is a key parameter which contributes to the thermal design and the quality of in-pile experiments performed in Material Testing Reactors (MTRs) for the study of nuclear materials and fuels under irradiation. Nuclear heating is typically measured in MTRs by radiometric calorimeters. However this kind of sensor has to be suited and improved in perspective of the new experimental conditions inside the channels of Jules Horowitz Reactor (JHR). In this paper, we study the responses of two non adiabatic differential calorimeter cells having the same geometric design, but different dimensions. These experimental works are carried out during a preliminary out-of-pile calibration operating procedure of these sensors which consists in simulating the sample heating by Joule effect. The influence of the imposed electrical power and of the forced cooling flow is determined on the sensor calibration curves. A more sensitive sensor leads to a quadratic calibration curve. This behavior difference of the two calorimetric configurations is explained by means of temperature and heat flux measurements performed with a new instrumented jacket. (authors)

  10. Preliminary Assessment of Suomi-NPP VIIRS On-orbit Radiometric Performance

    Science.gov (United States)

    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.

  11. Off-line radiometric analysis of Planck-LFI data

    Energy Technology Data Exchange (ETDEWEB)

    Tomasi, M; Mennella, A; Bersanelli, M [Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Galeotta, S; Maris, M [LFI-DPC INAF-OATs, Via Tiepolo 11, 34131 Trieste (Italy); Lowe, S R [Jodrell Bank Centre for Astrophysics, The University of Manchester, Manchester, M13 9PL (United Kingdom); Mendes, L [Planck Science Office, European Space Agency, ESAC, P.O. box 78, 28691 Villanueva de la Canada, Madrid (Spain); Leonardi, R; Meinhold, P [Department of Physics, University of California, Santa Barbara, CA 93106-9530 (United States); Villa, F; Sandri, M; Cuttaia, F; Terenzi, L; Valenziano, L; Butler, R C [INAF-IASF Bologna, Via Gobetti, 101, 40129, Bologna (Italy); Cappellini, B [INAF-IASF Milano, Via E. Bassini 15, 20133 Milano (Italy); Gregorio, A [Department of Physics, University of Trieste, Via Valerio, 2 Trieste I-34127 (Italy); Salmon, M J [Departamento de IngenierIa de Comunicaciones, Universidad de Cantabria, Avenida de los Castros s/n. 39005 Santander (Spain); Binko, P [ISDC Data Centre for Astrophysics, University of Geneva, ch. d' Ecogia 16, 1290 Versoix (Switzerland); D' Arcangelo, O, E-mail: tomasi@lambrate.inaf.i [IFP-CNR, Via Cozzi 53, Milano (Italy)

    2009-12-15

    The Planck Low Frequency Instrument (LFI) is an array of 22 pseudo-correlation radiometers on-board the Planck satellite to measure temperature and polarization anisotropies in the Cosmic Microwave Background (CMB) in three frequency bands (30, 44 and 70 GHz). To calibrate and verify the performances of the LFI, a software suite named LIFE has been developed. Its aims are to provide a common platform to use for analyzing the results of the tests performed on the single components of the instrument (RCAs, Radiometric Chain Assemblies) and on the integrated Radiometric Array Assembly (RAA). Moreover, its analysis tools are designed to be used during the flight as well to produce periodic reports on the status of the instrument. The LIFE suite has been developed using a multi-layered, cross-platform approach. It implements a number of analysis modules written in RSI IDL, each accessing the data through a portable and heavily optimized library of functions written in C and C++. One of the most important features of LIFE is its ability to run the same data analysis codes both using ground test data and real flight data as input. The LIFE software suite has been successfully used during the RCA/RAA tests and the Planck Integrated System Tests. Moreover, the software has also passed the verification for its in-flight use during the System Operations Verification Tests, held in October 2008.

  12. Off-line radiometric analysis of Planck-LFI data

    International Nuclear Information System (INIS)

    Tomasi, M; Mennella, A; Bersanelli, M; Galeotta, S; Maris, M; Lowe, S R; Mendes, L; Leonardi, R; Meinhold, P; Villa, F; Sandri, M; Cuttaia, F; Terenzi, L; Valenziano, L; Butler, R C; Cappellini, B; Gregorio, A; Salmon, M J; Binko, P; D'Arcangelo, O

    2009-01-01

    The Planck Low Frequency Instrument (LFI) is an array of 22 pseudo-correlation radiometers on-board the Planck satellite to measure temperature and polarization anisotropies in the Cosmic Microwave Background (CMB) in three frequency bands (30, 44 and 70 GHz). To calibrate and verify the performances of the LFI, a software suite named LIFE has been developed. Its aims are to provide a common platform to use for analyzing the results of the tests performed on the single components of the instrument (RCAs, Radiometric Chain Assemblies) and on the integrated Radiometric Array Assembly (RAA). Moreover, its analysis tools are designed to be used during the flight as well to produce periodic reports on the status of the instrument. The LIFE suite has been developed using a multi-layered, cross-platform approach. It implements a number of analysis modules written in RSI IDL, each accessing the data through a portable and heavily optimized library of functions written in C and C++. One of the most important features of LIFE is its ability to run the same data analysis codes both using ground test data and real flight data as input. The LIFE software suite has been successfully used during the RCA/RAA tests and the Planck Integrated System Tests. Moreover, the software has also passed the verification for its in-flight use during the System Operations Verification Tests, held in October 2008.

  13. The pre-flight calibration setup of the instrument SIMBIO-SYS onboard the mission BepiColombo

    Science.gov (United States)

    Poulet, F.; Rodriguez-Ferreira, J.; Arondel, A.; Dassas, K.; Eng, P.; Lami, P.; Langevin, Y.; Longval, Y.; Pradel, P.; Dami, M.

    2015-11-01

    BepiColombo, an European Space Agency (ESA) mission being conducted in cooperation with the Japan space agency, will explore Mercury with a set of eleven instruments onboard the spacecraft Mercury Planetary Orbiter (MPO). Among them, SIMBIO-SYS (Spectrometers and Imagers for MPO BepiColombo Integrated Observatory SYStem) is a complex instrument that will provide images and spectra in the 400-2000 nm wavelength range of the entire surface of Mercury. Pre-flight calibration of the SYMBIO-SYS instrument is mandatory for reliable scientific interpretation of images and spectra returned from the planet Mercury. This paper presents the calibration device designed and implemented for the specific requirements of this instrument. It mainly consists of a thermal vacuum chamber simulating the space environment, an optical bench collecting calibration sources and optical elements that simulate the conditions of Mercury observations, mechanical interfaces used for positioning the three channels inside the vacuum chamber, thermal interfaces to explore the operating temperatures, computer interfaces that allow to communicate with both the instrument and the calibration elements and synchronize the calibrations sequences with the status of the calibration device. As the major goal is the characterization of the radiometric performances of the three channels of SIMBIO-SYS, radiometric performances of the test setup evaluated by simulations and measurements are emphasized.

  14. Evaluation of Two Absolute Radiometric Normalization Algorithms for Pre-processing of Landsat Imagery

    Institute of Scientific and Technical Information of China (English)

    Xu Hanqiu

    2006-01-01

    In order to evaluate radiometric normalization techniques, two image normalization algorithms for absolute radiometric correction of Landsat imagery were quantitatively compared in this paper, which are the Illumination Correction Model proposed by Markham and Irish and the Illumination and Atmospheric Correction Model developed by the Remote Sensing and GIS Laboratory of the Utah State University. Relative noise, correlation coefficient and slope value were used as the criteria for the evaluation and comparison, which were derived from pseudo-invariant features identified from multitemtween the normalized multitemporal images were significantly reduced when the seasons of multitemporal images were different. However, there was no significant difference between the normalized and unnormalized images with a similar seasonal condition. Furthermore, the correction results of two algorithms are similar when the images are relatively clear with a uniform atmospheric condition. Therefore, the radiometric normalization procedures should be carried out if the multitemporal images have a significant seasonal difference.

  15. The Geostationary Lightning Mapper: Its Performance and Calibration

    Science.gov (United States)

    Christian, H. J., Jr.

    2015-12-01

    The Geostationary Lightning Mapper (GLM) has been developed to be an operational instrument on the GOES-R series of spacecraft. The GLM is a unique instrument, unlike other meteorological instruments, both in how it operates and in the information content that it provides. Instrumentally, it is an event detector, rather than an imager. While processing almost a billion pixels per second with 14 bits of resolution, the event detection process reduces the required telemetry bandwidth by almost 105, thus keeping the telemetry requirements modest and enabling efficient ground processing that leads to rapid data distribution to operational users. The GLM was designed to detect about 90 percent of the total lightning flashes within its almost hemispherical field of view. Based on laboratory calibration, we expect the on-orbit detection efficiency to be closer to 85%, making it the highest performing, large area coverage total lightning detector. It has a number of unique design features that will enable it have near uniform special resolution over most of its field of view and to operate with minimal impact on performance during solar eclipses. The GLM has no dedicated on-orbit calibration system, thus the ground-based calibration provides the bases for the predicted radiometric performance. A number of problems were encountered during the calibration of Flight Model 1. The issues arouse from GLM design features including its wide field of view, fast lens, the narrow-band interference filters located in both object and collimated space and the fact that the GLM is inherently a event detector yet the calibration procedures required both calibration of images and events. The GLM calibration techniques were based on those developed for the Lightning Imaging Sensor calibration, but there are enough differences between the sensors that the initial GLM calibration suggested that it is significantly more sensitive than its design parameters. The calibration discrepancies have

  16. Classification of high-resolution multi-swath hyperspectral data using Landsat 8 surface reflectance data as a calibration target and a novel histogram based unsupervised classification technique to determine natural classes from biophysically relevant fit parameters

    Science.gov (United States)

    McCann, C.; Repasky, K. S.; Morin, M.; Lawrence, R. L.; Powell, S. L.

    2016-12-01

    Compact, cost-effective, flight-based hyperspectral imaging systems can provide scientifically relevant data over large areas for a variety of applications such as ecosystem studies, precision agriculture, and land management. To fully realize this capability, unsupervised classification techniques based on radiometrically-calibrated data that cluster based on biophysical similarity rather than simply spectral similarity are needed. An automated technique to produce high-resolution, large-area, radiometrically-calibrated hyperspectral data sets based on the Landsat surface reflectance data product as a calibration target was developed and applied to three subsequent years of data covering approximately 1850 hectares. The radiometrically-calibrated data allows inter-comparison of the temporal series. Advantages of the radiometric calibration technique include the need for minimal site access, no ancillary instrumentation, and automated processing. Fitting the reflectance spectra of each pixel using a set of biophysically relevant basis functions reduces the data from 80 spectral bands to 9 parameters providing noise reduction and data compression. Examination of histograms of these parameters allows for determination of natural splitting into biophysical similar clusters. This method creates clusters that are similar in terms of biophysical parameters, not simply spectral proximity. Furthermore, this method can be applied to other data sets, such as urban scenes, by developing other physically meaningful basis functions. The ability to use hyperspectral imaging for a variety of important applications requires the development of data processing techniques that can be automated. The radiometric-calibration combined with the histogram based unsupervised classification technique presented here provide one potential avenue for managing big-data associated with hyperspectral imaging.

  17. Broadband Radiometric LED Measurements

    OpenAIRE

    Eppeldauer, G. P.; Cooksey, C. C.; Yoon, H. W.; Hanssen, L. M.; Podobedov, V. B.; Vest, R. E.; Arp, U.; Miller, C. C.

    2016-01-01

    At present, broadband radiometric measurements of LEDs with uniform and low-uncertainty results are not available. Currently, either complicated and expensive spectral radiometric measurements or broadband photometric LED measurements are used. The broadband photometric measurements are based on the CIE standardized V(��) function, which cannot be used in the UV range and leads to large errors when blue or red LEDs are measured in its wings, where the realization is always poor. Reference irr...

  18. Radiometric assays for glycerol, glucose, and glycogen

    International Nuclear Information System (INIS)

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

    1989-01-01

    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

  19. Solid laboratory calibration of a nonimaging spectroradiometer.

    Science.gov (United States)

    Schaepman, M E; Dangel, S

    2000-07-20

    Field-based nonimaging spectroradiometers are often used in vicarious calibration experiments for airborne or spaceborne imaging spectrometers. The calibration uncertainties associated with these ground measurements contribute substantially to the overall modeling error in radiance- or reflectance-based vicarious calibration experiments. Because of limitations in the radiometric stability of compact field spectroradiometers, vicarious calibration experiments are based primarily on reflectance measurements rather than on radiance measurements. To characterize the overall uncertainty of radiance-based approaches and assess the sources of uncertainty, we carried out a full laboratory calibration. This laboratory calibration of a nonimaging spectroradiometer is based on a measurement plan targeted at achieving a calibration. The individual calibration steps include characterization of the signal-to-noise ratio, the noise equivalent signal, the dark current, the wavelength calibration, the spectral sampling interval, the nonlinearity, directional and positional effects, the spectral scattering, the field of view, the polarization, the size-of-source effects, and the temperature dependence of a particular instrument. The traceability of the radiance calibration is established to a secondary National Institute of Standards and Technology calibration standard by use of a 95% confidence interval and results in an uncertainty of less than ?7.1% for all spectroradiometer bands.

  20. Calibration of circular aperture area using vision probe at inmetro

    Directory of Open Access Journals (Sweden)

    Costa Pedro Bastos

    2016-01-01

    Full Text Available Circular aperture areas are standards of high importance for the realization of photometric and radiometric measurements, where the accuracy of these measures is related to the accuracy of the circular aperture area calibrations. In order to attend the requirement for traceability was developed in Brazilian metrology institute, a methodology for circular aperture area measurement as requirements from the radiometric and photometric measurements. In the developed methodology apertures are measured by non-contact measurement through images of the aperture edges captured by a camera. These images are processed using computer vision techniques and then the values of the circular aperture area are determined.

  1. SCIAMACHY Level 1 data: calibration concept and in-flight calibration

    Science.gov (United States)

    Lichtenberg, G.; Kleipool, Q.; Krijger, J. M.; van Soest, G.; van Hees, R.; Tilstra, L. G.; Acarreta, J. R.; Aben, I.; Ahlers, B.; Bovensmann, H.; Chance, K.; Gloudemans, A. M. S.; Hoogeveen, R. W. M.; Jongma, R. T. N.; Noël, S.; Piters, A.; Schrijver, H.; Schrijvers, C.; Sioris, C. E.; Skupin, J.; Slijkhuis, S.; Stammes, P.; Wuttke, M.

    2006-11-01

    The calibration of SCIAMACHY was thoroughly checked since the instrument was launched on-board ENVISAT in February 2002. While SCIAMACHY's functional performance is excellent since launch, a number of technical difficulties have appeared, that required adjustments to the calibration. The problems can be separated into three types: (1) Those caused by the instrument and/or platform environment. Among these are the high water content in the satellite structure and/or MLI layer. This results in the deposition of ice on the detectors in channels 7 and 8 which seriously affects the retrievals in the IR, mostly because of the continuous change of the slit function caused by scattering of the light through the ice layer. Additionally a light leak in channel 7 severely hampers any retrieval from this channel. (2) Problems due to errors in the on-ground calibration and/or data processing affecting for example the radiometric calibration. A new approach based on a mixture of on-ground and in-flight data is shortly described here. (3) Problems caused by principal limitations of the calibration concept, e.g. the possible appearance of spectral structures after the polarisation correction due to unavoidable errors in the determination of atmospheric polarisation. In this paper we give a complete overview of the calibration and problems that still have to be solved. We will also give an indication of the effect of calibration problems on retrievals where possible. Since the operational processing chain is currently being updated and no newly processed data are available at this point in time, for some calibration issues only a rough estimate of the effect on Level 2 products can be given. However, it is the intention of this paper to serve as a future reference for detailed studies into specific calibration issues.

  2. Online Resource for Earth-Observing Satellite Sensor Calibration

    Science.gov (United States)

    McCorkel, J.; Czapla-Myers, J.; Thome, K.; Wenny, B.

    2015-01-01

    The Radiometric Calibration Test Site (RadCaTS) at Railroad Valley Playa, Nevada is being developed by the University of Arizona to enable improved accuracy and consistency for airborne and satellite sensor calibration. Primary instrumentation at the site consists of ground-viewing radiometers, a sun photometer, and a meteorological station. Measurements made by these instruments are used to calculate surface reflectance, atmospheric properties and a prediction for top-of-atmosphere reflectance and radiance. This work will leverage research for RadCaTS, and describe the requirements for an online database, associated data formats and quality control, and processing levels.

  3. A procedure to validate and correct the {sup 13}C chemical shift calibration of RNA datasets

    Energy Technology Data Exchange (ETDEWEB)

    Aeschbacher, Thomas; Schubert, Mario, E-mail: schubert@mol.biol.ethz.ch; Allain, Frederic H.-T., E-mail: allain@mol.biol.ethz.ch [ETH Zuerich, Institute for Molecular Biology and Biophysics (Switzerland)

    2012-02-15

    Chemical shifts reflect the structural environment of a certain nucleus and can be used to extract structural and dynamic information. Proper calibration is indispensable to extract such information from chemical shifts. Whereas a variety of procedures exist to verify the chemical shift calibration for proteins, no such procedure is available for RNAs to date. We present here a procedure to analyze and correct the calibration of {sup 13}C NMR data of RNAs. Our procedure uses five {sup 13}C chemical shifts as a reference, each of them found in a narrow shift range in most datasets deposited in the Biological Magnetic Resonance Bank. In 49 datasets we could evaluate the {sup 13}C calibration and detect errors or inconsistencies in RNA {sup 13}C chemical shifts based on these chemical shift reference values. More than half of the datasets (27 out of those 49) were found to be improperly referenced or contained inconsistencies. This large inconsistency rate possibly explains that no clear structure-{sup 13}C chemical shift relationship has emerged for RNA so far. We were able to recalibrate or correct 17 datasets resulting in 39 usable {sup 13}C datasets. 6 new datasets from our lab were used to verify our method increasing the database to 45 usable datasets. We can now search for structure-chemical shift relationships with this improved list of {sup 13}C chemical shift data. This is demonstrated by a clear relationship between ribose {sup 13}C shifts and the sugar pucker, which can be used to predict a C2 Prime - or C3 Prime -endo conformation of the ribose with high accuracy. The improved quality of the chemical shift data allows statistical analysis with the potential to facilitate assignment procedures, and the extraction of restraints for structure calculations of RNA.

  4. pH sensor calibration procedure

    OpenAIRE

    Artero Delgado, Carola; Nogueras Cervera, Marc; Manuel Lázaro, Antonio; Prat Tasias, Jordi; Prat Farran, Joana d'Arc

    2013-01-01

    This paper describes the calibration of pH sensor located at the OBSEA marine Observatory. This instrument is based on an industrial pH electrode that is connected to a CTD instrument (Conductivity, Temperature, and Depth ). The calibration of the pH sensor has been done using a high precision spectrophotometer pH meter from Institute of Marine Sciences (ICM), and in this way it has been obtained a numerical function for the p H sensor propor...

  5. Procedure for the Selection and Validation of a Calibration Model I-Description and Application.

    Science.gov (United States)

    Desharnais, Brigitte; Camirand-Lemyre, Félix; Mireault, Pascal; Skinner, Cameron D

    2017-05-01

    Calibration model selection is required for all quantitative methods in toxicology and more broadly in bioanalysis. This typically involves selecting the equation order (quadratic or linear) and weighting factor correctly modelizing the data. A mis-selection of the calibration model will generate lower quality control (QC) accuracy, with an error up to 154%. Unfortunately, simple tools to perform this selection and tests to validate the resulting model are lacking. We present a stepwise, analyst-independent scheme for selection and validation of calibration models. The success rate of this scheme is on average 40% higher than a traditional "fit and check the QCs accuracy" method of selecting the calibration model. Moreover, the process was completely automated through a script (available in Supplemental Data 3) running in RStudio (free, open-source software). The need for weighting was assessed through an F-test using the variances of the upper limit of quantification and lower limit of quantification replicate measurements. When weighting was required, the choice between 1/x and 1/x2 was determined by calculating which option generated the smallest spread of weighted normalized variances. Finally, model order was selected through a partial F-test. The chosen calibration model was validated through Cramer-von Mises or Kolmogorov-Smirnov normality testing of the standardized residuals. Performance of the different tests was assessed using 50 simulated data sets per possible calibration model (e.g., linear-no weight, quadratic-no weight, linear-1/x, etc.). This first of two papers describes the tests, procedures and outcomes of the developed procedure using real LC-MS-MS results for the quantification of cocaine and naltrexone. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. CALIPSO lidar calibration at 532 nm: version 4 nighttime algorithm

    Directory of Open Access Journals (Sweden)

    J. Kar

    2018-03-01

    Full Text Available Data products from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP on board Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO were recently updated following the implementation of new (version 4 calibration algorithms for all of the Level 1 attenuated backscatter measurements. In this work we present the motivation for and the implementation of the version 4 nighttime 532 nm parallel channel calibration. The nighttime 532 nm calibration is the most fundamental calibration of CALIOP data, since all of CALIOP's other radiometric calibration procedures – i.e., the 532 nm daytime calibration and the 1064 nm calibrations during both nighttime and daytime – depend either directly or indirectly on the 532 nm nighttime calibration. The accuracy of the 532 nm nighttime calibration has been significantly improved by raising the molecular normalization altitude from 30–34 km to the upper possible signal acquisition range of 36–39 km to substantially reduce stratospheric aerosol contamination. Due to the greatly reduced molecular number density and consequently reduced signal-to-noise ratio (SNR at these higher altitudes, the signal is now averaged over a larger number of samples using data from multiple adjacent granules. Additionally, an enhanced strategy for filtering the radiation-induced noise from high-energy particles was adopted. Further, the meteorological model used in the earlier versions has been replaced by the improved Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2, model. An aerosol scattering ratio of 1.01 ± 0.01 is now explicitly used for the calibration altitude. These modifications lead to globally revised calibration coefficients which are, on average, 2–3 % lower than in previous data releases. Further, the new calibration procedure is shown to eliminate biases at high altitudes that were present in earlier versions and

  7. Automated gamma spectrometry and data analysis on radiometric neutron dosimeters

    International Nuclear Information System (INIS)

    Matsumoto, W.Y.

    1983-01-01

    An automated gamma-ray spectrometry system was designed and implemented by the Westinghouse Hanford Company at the Hanford Engineering Development Laboratory (HEDL) to analyze radiometric neutron dosimeters. Unattended, automatic, 24 hour/day, 7 day/week operation with online data analysis and mainframe-computer compatible magnetic tape output are system features. The system was used to analyze most of the 4000-plus radiometric monitors (RM's) from extensive reactor characterization tests during startup and initial operation of th Fast Flux Test Facility (FFTF). The FFTF, operated by HEDL for the Department of Energy, incorporates a 400 MW(th) sodium-cooled fast reactor. Aumomated system hardware consists of a high purity germanium detector, a computerized multichannel analyzer data acquisition system (Nuclear Data, Inc. Model 6620) with two dual 2.5 Mbyte magnetic disk drives plus two 10.5 inch reel magnetic tape units for mass storage of programs/data and an automated Sample Changer-Positioner (ASC-P) run with a programmable controller. The ASC-P has a 200 sample capacity and 12 calibrated counting (analysis) positions ranging from 6 inches (15 cm) to more than 20 feet (6.1 m) from the detector. The system software was programmed in Fortran at HEDL, except for the Nuclear Data, Inc. Peak Search and Analysis Program and Disk Operating System (MIDAS+)

  8. Radiometric weighing devices. Part 1 and 2

    International Nuclear Information System (INIS)

    Glaeser, M.

    1985-01-01

    Proceeding from the physical and mathematical fundamentals and from the types of radiometric weighing devices presently available, the radiation protection problems arising from the application of radiometric gages in industry and agriculture are discussed. Nuclear weighing devices have been found to be effective from economic point of view but in some cases gravimetric conveyor weighers are indispensable. Information and guidance is given especially for users of radiometric weighing devices. 91 refs., 69 figs., and 8 tabs

  9. Laboratory panel and radiometer calibration

    CSIR Research Space (South Africa)

    Deadman, AJ

    2011-07-01

    Full Text Available stream_source_info Griffith1_2011.pdf.txt stream_content_type text/plain stream_size 16659 Content-Encoding ISO-8859-1 stream_name Griffith1_2011.pdf.txt Content-Type text/plain; charset=ISO-8859-1 LABORATORY PANEL... of Land surface imaging through a ground reference standard test site?, on http://qa4eo.org/documentation.html, 2009. [2] K. J. Thome, D. L. Helder, D. Aaron, and J. D. Dewald, ?Landsat-5 TM and Landsat-7 ETM+ Absolute Radiometric Calibration Using...

  10. Calibration and Validation of the National Ecological Observatory Network's Airborne Imaging Spectrometers

    Science.gov (United States)

    Leisso, N.

    2015-12-01

    The National Ecological Observatory Network (NEON) is being constructed by the National Science Foundation and is slated for completion in 2017. NEON is designed to collect data to improve the understanding of changes in observed ecosystems. The observatory will produce data products on a variety of spatial and temporal scales collected from individual sites strategically located across the U.S. including Alaska, Hawaii, and Puerto Rico. Data sources include standardized terrestrial, instrumental, and aquatic observation systems in addition to three airborne remote sensing observation systems installed into leased Twin Otter aircraft. The Airborne Observation Platforms (AOP) are designed to collect 3-band aerial imagery, waveform and discrete LiDAR, and high-fidelity imaging spectroscopy data over the NEON sites annually at or near peak-greenness. The NEON Imaging Spectrometer (NIS) is a Visible and Shortwave Infrared (VSWIR) sensor designed by NASA JPL for ecological applications. Spectroscopic data is collected at 5-nm intervals across the solar-reflective spectral region (380-nm to 2500-nm) in a 34-degree FOV swath. A key uncertainty driver to the derived remote sensing NEON data products is the calibration of the imaging spectrometers. In addition, the calibration and accuracy of the higher-level data product algorithms is essential to the overall NEON mission to detect changes in the collected ecosystems over the 30-year expected lifetime. The typical calibration workflow of the NIS consists of the characterizing the focal plane, spectral calibration, and radiometric calibration. Laboratory spectral calibration is based on well-defined emission lines in conjunction with a scanning monochromator to define the individual spectral response functions. The radiometric calibration is NIST traceable and transferred to the NIS with an integrating sphere calibrated through the use of transfer radiometers. The laboratory calibration is monitored and maintained through

  11. Radon in air calibration procedure: A primary method

    International Nuclear Information System (INIS)

    Lucas, H.F.; Markun, F.

    1988-01-01

    A procedure has been developed for preparing 3- to 9-iota volumes of air under natural conditions with a known concentration of /sup 222/Rn to be used for calibrating radon systems. Air is passed into a plastic bag through a standard /sup 226/Ra solution (prepared by the U.S. National Bureau of Standards) contained in an emanation flask. This plastic bag retains /sup 222/Rn with little loss into or through the bag walls. The mean ratios of the /sup 222/Rn in the air at 2 and 7 days after filling to that immediately after filling were -.992 +- 0.006 and 0.969 +- 0.008, which suggests a rate of radon loss into the bag of 0.4 +- 0.1%/day

  12. Exploring the Feasibility cold-FET Calibration Standards to Improve Radiometric Measurements

    Data.gov (United States)

    National Aeronautics and Space Administration — This work seeks to further the development of the cold-FET calibration technology designed f next generation multi-band microwave instruments for space-based remote...

  13. A versatile calibration procedure for portable coded aperture gamma cameras and RGB-D sensors

    Science.gov (United States)

    Paradiso, V.; Crivellaro, A.; Amgarou, K.; de Lanaute, N. Blanc; Fua, P.; Liénard, E.

    2018-04-01

    The present paper proposes a versatile procedure for the geometrical calibration of coded aperture gamma cameras and RGB-D depth sensors, using only one radioactive point source and a simple experimental set-up. Calibration data is then used for accurately aligning radiation images retrieved by means of the γ-camera with the respective depth images computed with the RGB-D sensor. The system resulting from such a combination is thus able to retrieve, automatically, the distance of radioactive hotspots by means of pixel-wise mapping between gamma and depth images. This procedure is of great interest for a wide number of applications, ranging from precise automatic estimation of the shape and distance of radioactive objects to Augmented Reality systems. Incidentally, the corresponding results validated the choice of a perspective design model for a coded aperture γ-camera.

  14. Radiometric dating

    International Nuclear Information System (INIS)

    Das, N.R.

    2017-01-01

    Since the discovery of natural radioactivity in uranium, in the last decade of the nineteenth century, the nuclear property of radioactive decay of radionuclides at immutable rates has been effectively utilized in dating of varieties of naturally occurring geological matrices and the organisms which constantly replenish their "1"4C supply through respiration when alive on earth. During the period, applications of radiometric dating techniques have been extensively diversified and have enabled the geologists to indicate the absolute time scales of geological formations and the evolution of the solar system, the earth, meteorites, lunar rocks, etc. and the archaeologists to record the facts of history of several important events like dinosaur era, Iceman, the Shroud in Turin and many other ancient artefacts. In the development of dating methods, varieties of naturally occurring radio-isotopic systems with favorable half-lives ranging from about 10 years to over 100 billion years have been used as radiometric clocks. (author)

  15. Design and realization of an active SAR calibrator for TerraSAR-X

    Science.gov (United States)

    Dummer, Georg; Lenz, Rainer; Lutz, Benjamin; Kühl, Markus; Müller-Glaser, Klaus D.; Wiesbeck, Werner

    2005-10-01

    TerraSAR-X is a new earth observing satellite which will be launched in spring 2006. It carries a high resolution X-band SAR sensor. For high image data quality, accurate ground calibration targets are necessary. This paper describes a novel system concept for an active and highly integrated, digitally controlled SAR system calibrator. A total of 16 active transponder and receiver systems and 17 receiver only systems will be fabricated for a calibration campaign. The calibration units serve for absolute radiometric calibration of the SAR image data. Additionally, they are equipped with an extra receiver path for two dimensional satellite antenna pattern recognition. The calibrator is controlled by a dedicated digital Electronic Control Unit (ECU). The different voltages needed by the calibrator and the ECU are provided by the third main unit called Power Management Unit (PMU).

  16. A general procedure for thermomechanical calibration of nano/micro-mechanical resonators

    International Nuclear Information System (INIS)

    Hauer, B.D.; Doolin, C.; Beach, K.S.D.; Davis, J.P.

    2013-01-01

    We describe a general procedure to calibrate the detection of a nano/micro-mechanical resonator’s displacement as it undergoes thermal Brownian motion. A brief introduction to the equations of motion for such a resonator is presented, followed by a detailed derivation of the corresponding power spectral density (PSD) function, which is identical in all situations aside from a system-dependent effective mass value. The effective masses for a number of different resonator geometries are determined using both finite element method (FEM) modeling and analytical calculations. -- Highlights: •Model micro- and nanomechanical resonators displaced by their own thermal motion. •Review the theoretical framework for describing thermomechanical systems. •Present a recipe for measurement calibration on devices of arbitrary shape. •Point out and correct inconsistencies in the existing literature. •Provide an authoritative guide and reference for practitioners in this area

  17. A general procedure for thermomechanical calibration of nano/micro-mechanical resonators

    Energy Technology Data Exchange (ETDEWEB)

    Hauer, B.D., E-mail: bhauer@ualberta.ca; Doolin, C.; Beach, K.S.D., E-mail: kbeach@ualberta.ca; Davis, J.P., E-mail: jdavis@ualberta.ca

    2013-12-15

    We describe a general procedure to calibrate the detection of a nano/micro-mechanical resonator’s displacement as it undergoes thermal Brownian motion. A brief introduction to the equations of motion for such a resonator is presented, followed by a detailed derivation of the corresponding power spectral density (PSD) function, which is identical in all situations aside from a system-dependent effective mass value. The effective masses for a number of different resonator geometries are determined using both finite element method (FEM) modeling and analytical calculations. -- Highlights: •Model micro- and nanomechanical resonators displaced by their own thermal motion. •Review the theoretical framework for describing thermomechanical systems. •Present a recipe for measurement calibration on devices of arbitrary shape. •Point out and correct inconsistencies in the existing literature. •Provide an authoritative guide and reference for practitioners in this area.

  18. Experimental procedures for the calibration of scintillation cells used in the determination of radon gas concentrations

    International Nuclear Information System (INIS)

    Grenier, M; Bigu, J.

    1982-02-01

    Experimental and analytical procedures are described for the calibration of scintillation cells used for the determination of radon gas concentration. In-house designed and built scintillation cells, used routinely in the monitoring of radon gas in uranium mine underground environments and in the laboratory, were calibrated. The cells had a volume of approximately 158 cm 3 and an α-counting efficiency ranging from 50% to 64%. Calibration factors for the cells were determined. Values ranged approximately from 0.177 cpm/pCiL -1 (4.77 cpm/BqL -1 ) to 0.224 cpm/pCiL -1 (6.05 cpm/BqL -1 ). The calibration facilities at the Elliot Lake Laboratory are briefly described

  19. Study of the use of a Phoswich detector for aerial radiometric surveys

    International Nuclear Information System (INIS)

    Schneid, E.J.; Lagin, L.J.

    1981-09-01

    Large volume, actively shielded Phoswich detector configurations were investigated for application in airborne radiometric survey systems in order to increase the sensitivity to ground-level potassium, uranium, and thorium compared to conventional NaI detectors of similar sizes. One Phoswich configuration was fabricated and flight tested. The flight measurements with the Phoswich detector and a conventional NaI detector utilized the Bendix Field Engineering Corporation - US Department of Energy/Grand Junction Office Walker Field Aerial Radiometric Survey Calibration Facility, the DOE dynamic test range, and a region in the southwest portion of the Lubbock, Texas, Quadrangle. The tests demonstrated that the Phoswich detector can function in an operational environment and does provide greater sensitivity to ground-level potassium, uranium, and thorium concentration than the conventional NaI detector. The multicrystal configuration for the Phoswich detector provided the capability to simultaneously measure the atmospheric radon background without the need of heavy lead shields. The flight tests indicated that the Phoswich detector has directional discrimination capability not available with conventional NaI detector systems. This directional capability can be used to distinguish the location, relative to the aircraft, of localized strong sources of radiation

  20. Radiometric Evaluation of SNPP VIIRS Band M11 via Sub-Kilometer Intercomparison with Aqua MODIS Band 7 over Snowy Scenes

    Directory of Open Access Journals (Sweden)

    Mike Chu

    2018-03-01

    Full Text Available A refined intersensor comparison study is carried out to evaluate the radiometric stability of the 2257 nm channel (M11 of the first Visible Infrared Imaging Radiometer Suite (VIIRS aboard the Suomi National Polar-orbiting Partnership (SNPP satellite. This study is initiated as part of the examination into the performance of key shortwave infrared (SWIR bands for SNPP VIIRS ocean color data processing and applications, with Band M11 playing key role over turbid and inland waters. The evaluation utilizes simultaneous nadir overpasses (SNOs to compare SNPP VIIRS Band M11 against Band 7 of the MODerate-resolution Imaging Spectroradiometer (MODIS in the Aqua satellite over concurrently observed scenes. The standard result of the radiance comparison is a seemingly uncontrolled and inconsistent time series unsuitable for further analyses, in great contrast to other matching band-pairs whose radiometric comparisons are typically stable around 1.0 within 1% variation. The mismatching relative spectral response (RSR between the two respective bands, with SNPP VIIRS M11 at 2225 to 2275 nm and Aqua MODIS B7 at 2125 to 2175 nm, is demonstrated to be the cause of the large variation because of the different dependence of the spectral responses of the two bands over identical scenes. A consistent radiometric comparison time series, however, can be extracted from SNO events that occur over snowy surfaces. A customized selection and analysis procedure successfully identifies the snowy scenes within the SNO events and builds a stable comparison time series. Particularly instrumental for the success of the comparison is the use of the half-kilometer spatial resolution data of Aqua MODIS B7 that significantly enhances the statistics. The final refined time series of Aqua MODIS B7 radiance over the SNPP VIIRS M11 radiance is stable at around 0.39 within 2.5% showing no evidence of drift. The radiometric ratio near 0.39 suggests the strong presence of medium

  1. JPSS-1 VIIRS Pre-Launch Radiometric Performance

    Science.gov (United States)

    Oudrari, Hassan; Mcintire, Jeffrey; Xiong, Xiaoxiong; Butler, James; Ji, Qiang; Schwarting, Tom; Zeng, Jinan

    2015-01-01

    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 m to 12.01 m, 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. A Consistent EPIC Visible Channel Calibration Using VIIRS and MODIS as a Reference.

    Science.gov (United States)

    Haney, C.; Doelling, D. R.; Minnis, P.; Bhatt, R.; Scarino, B. R.; Gopalan, A.

    2017-12-01

    The Earth Polychromatic Imaging Camera (EPIC) aboard the Deep Space Climate Observatory (DSCOVR) satellite constantly images the sunlit disk of Earth from the Lagrange-1 (L1) point in 10 spectral channels spanning the UV, VIS, and NIR spectrums. Recently, the DSCOVR EPIC team has publicly released version 2 dataset, which has implemented improved navigation, stray-light correction, and flat-fielding of the CCD array. The EPIC 2-year data record must be well-calibrated for consistent cloud, aerosol, trace gas, land use and other retrievals. Because EPIC lacks onboard calibrators, the observations made by EPIC channels must be calibrated vicariously using the coincident measurements from radiometrically stable instruments that have onboard calibration systems. MODIS and VIIRS are best-suited instruments for this task as they contain similar spectral bands that are well-calibrated onboard using solar diffusers and lunar tracking. We have previously calibrated the EPIC version 1 dataset by using EPIC and VIIRS angularly matched radiance pairs over both all-sky ocean and deep convective clouds (DCC). We noted that the EPIC image required navigations adjustments, and that the EPIC stray-light correction provided an offset term closer to zero based on the linear regression of the EPIC and VIIRS ray-matched radiance pairs. We will evaluate the EPIC version 2 navigation and stray-light improvements using the same techniques. In addition, we will monitor the EPIC channel calibration over the two years for any temporal degradation or anomalous behavior. These two calibration methods will be further validated using desert and DCC invariant Earth targets. The radiometric characterization of the selected invariant targets is performed using multiple years of MODIS and VIIRS measurements. Results of these studies will be shown at the conference.

  3. Calibration and intercomparison methods of dose calibrators used in nuclear medicine facilities

    International Nuclear Information System (INIS)

    Costa, Alessandro Martins da

    1999-01-01

    Dose calibrators are used in most of the nuclear medicine facilities to determine the amount of radioactivity administered to a patient in a particular investigation or therapeutic procedure. It is therefore of vital importance that the equipment used presents good performance and is regular;y calibrated at a authorized laboratory. This occurs of adequate quality assurance procedures are carried out. Such quality control tests should be performed daily, other biannually or yearly, testing, for example, its accuracy and precision, the reproducibility and response linearity. In this work a commercial dose calibrator was calibrated with solution of radionuclides used in nuclear medicine. Simple instrument tests, such as response linearity and the response variation of the source volume increase at a constant source activity concentration, were performed. This instrument can now be used as a working standard for calibration of other dose calibrators/ An intercomparison procedure was proposed as a method of quality control of dose calibrators used in nuclear medicine facilities. (author)

  4. MODIS Aqua Optical Throughput Degradation Impact on Relative Spectral Response and Calibration on Ocean Color Products

    Science.gov (United States)

    Lee, Shihyan; Meister, Gerhard

    2017-01-01

    Since Moderate Resolution Imaging Spectroradiometer Aqua's launch in 2002, the radiometric system gains of the reflective solar bands have been degrading, indicating changes in the systems optical throughput. To estimate the optical throughput degradation, the electronic gain changes were estimated and removed from the measured system gain. The derived optical throughput degradation shows a rate that is much faster in the shorter wavelengths than the longer wavelengths. The wavelength-dependent optical throughput degradation modulated the relative spectral response (RSR) of the bands. In addition, the optical degradation is also scan angle-dependent due to large changes in response versus the scan angle over time. We estimated the modulated RSR as a function of time and scan angles and its impacts on sensor radiometric calibration for the ocean science. Our results show that the calibration bias could be up to 1.8 % for band 8 (412 nm) due to its larger out-of-band response. For the other ocean bands, the calibration biases are much smaller with magnitudes at least one order smaller.

  5. Radiometric analysis of the longwave infrared channel of the Thematic Mapper on LANDSAT 4 and 5

    Science.gov (United States)

    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.

  6. Intercomparison of calibration procedures of high dose rate 192 Ir sources in Brazil and a proposal of a new methodology

    International Nuclear Information System (INIS)

    Marechal, M.H.; Almeida, C.E. de

    1998-01-01

    The objective of this paper is to report the results of an intercomparison of the calibration procedures for 192 Ir sources presently in use in Brazil and to proposal a calibration procedure to derive the N k for a Farmer type ionization chamber for 192 Ir energy by interpolating from a 60 Co gamma-rays and 250 kV x-rays calibration factors. the intercomparison results were all within ± 3.0 % except one case where 4.6 % was observed and latter identified as a problem with N-k value for X-rays. The method proposed by the present work make possible the improvement of the metrological coherence among the calibration laboratories and their users once the N k values could then provided by any of the members of SSDL network. (Author)

  7. KERNEL MAD ALGORITHM FOR RELATIVE RADIOMETRIC NORMALIZATION

    Directory of Open Access Journals (Sweden)

    Y. Bai

    2016-06-01

    Full Text Available 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.

  8. Experimental comparison between total calibration factors and components calibration factors of reference dosemeters used in secondary standard laboratory dosemeters

    International Nuclear Information System (INIS)

    Silva, T.A. da.

    1981-06-01

    A quantitative comparison of component calibration factors with the corresponding overall calibration factor was used to evaluate the adopted component calibration procedure in regard to parasitic elements. Judgement of significance is based upon the experimental uncertainty of a well established procedure for determination of the overall calibration factor. The experimental results obtained for different ionization chambers and different electrometers demonstrate that for one type of electrometer the parasitic elements have no influence on its sensitivity considering the experimental uncertainty of the calibration procedures. In this case the adopted procedure for determination of component calibration factors is considered to be equivalent to the procedure of determination of the overall calibration factor and thus might be used as a strong quality control measure in routine calibration. (Author) [pt

  9. Procedures for calibration of clinical dosemeters of radiotherapy with gamma radiation Co-60 in the IPEN-CNEN, Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Damatto, Willian B.; Santos, Gelson P.; Potiens, Maria da Penha A.; Vivolo, Vitor

    2009-01-01

    The periodic calibration of clinic dosimeters is a very important task, because those measurement systems performing the control quality of the radioactive source and for that assure the control quality of the patient dose estimative. This paper shows the calibration procedures and routine improved in the calibration laboratory of IPEN/CNEN-SP to be applied to the clinic dosimeters following international and national recommendations and yet the spend care that the clients should have with the utilization of that measurement systems for control quality of the radiotherapy procedures, for reduce the dose received for patient, and workers, and for increase the confidence level of the measurements.(author)

  10. A recommendation for revised dose calibrator measurement procedures for 89Zr and 124I.

    Directory of Open Access Journals (Sweden)

    Bradley J Beattie

    Full Text Available Because of their chemical properties and multiday half lives, iodine-124 and zirconium-89 are being used in a growing number of PET imaging studies. Some aspects of their quantitation, however, still need attention. For (89Zr the PET images should, in principle, be as quantitatively accurate as similarly reconstructed 18F measurements. We found, however, that images of a 20 cm well calibration phantom containing (89Zr underestimated the activity by approximately 10% relative to a dose calibrator measurement (Capintec CRC-15R using a published calibration setting number of 465. PET images of (124I, in contrast, are complicated by the contribution of decays in cascade that add spurious coincident events to the PET data. When these cascade coincidences are properly accounted for, quantitatively accurate images should be possible. We found, however, that even with this correction we still encountered what appeared to be a large variability in the accuracy of the PET images when compared to dose calibrator measurements made using the calibration setting number, 570, recommended by Capintec. We derive new calibration setting numbers for (89Zr and (124I based on their 511 keV photon peaks as measured on an HPGe detector. The peaks were calibrated relative to an 18F standard, the activity level of which was precisely measured in a dose calibrator under well-defined measurement conditions. When measuring (89Zr on a Capintec CRC-15R we propose the use of calibration setting number 517. And for (124I, we recommend the use of a copper filter surrounding the sample and the use of calibration setting number 494. The new dose calibrator measurement procedures we propose will result in more consistent and accurate radioactivity measurements of (89Zr and (124I. These and other positron emitting radionuclides can be accurately calibrated relative to 18F based on measurements of their 511 keV peaks and knowledge of their relative positron abundances.

  11. Calibration

    International Nuclear Information System (INIS)

    Greacen, E.L.; Correll, R.L.; Cunningham, R.B.; Johns, G.G.; Nicolls, K.D.

    1981-01-01

    Procedures common to different methods of calibration of neutron moisture meters are outlined and laboratory and field calibration methods compared. Gross errors which arise from faulty calibration techniques are described. The count rate can be affected by the dry bulk density of the soil, the volumetric content of constitutional hydrogen and other chemical components of the soil and soil solution. Calibration is further complicated by the fact that the neutron meter responds more strongly to the soil properties close to the detector and source. The differences in slope of calibration curves for different soils can be as much as 40%

  12. A novel method for destriping of OCM-2 data and radiometric performance analysis for improved ocean color data products

    Science.gov (United States)

    Singh, Rakesh Kumar; Shanmugam, Palanisamy

    2018-06-01

    Despite the capability of Ocean Color Monitor aboard Oceansat-2 satellite to provide frequent, high-spatial resolution, visible and near-infrared images for scientific research on coastal zones and climate data records over the global ocean, the generation of science quality ocean color products from OCM-2 data has been hampered by serious vertical striping artifacts and poor calibration of detectors. These along-track stripes are the results of variations in the relative response of the individual detectors of the OCM-2 CCD array. The random unsystematic stripes and bandings on the scene edges affect both visual interpretation and radiometric integrity of remotely sensed data, contribute to confusion in the aerosol correction process, and multiply and propagate into higher level ocean color products generated by atmospheric correction and bio-optical algorithms. Despite a number of destriping algorithms reported in the literature, complete removal of stripes without residual effects and signal distortion in both low- and high-level products is still challenging. Here, a new operational algorithm has been developed that employs an inverted gaussian function to estimate error fraction parameters, which are uncorrelated and vary in spatial, spectral and temporal domains. The algorithm is tested on a large number of OCM-2 scenes from Arabian Sea and Bay of Bengal waters contaminated with severe stripes. The destriping effectiveness of this approach is then evaluated by means of various qualitative and quantitative analyses, and by comparison with the results of the previously reported method. Clearly, the present method is more effective in terms of removing the stripe noise while preserving the radiometric integrity of the destriped OCM-2 data. Furthermore, a preliminary time-dependent calibration of the OCM-2 sensor is performed with several match-up in-situ data to evaluate its radiometric performance for ocean color applications. OCM-2 derived water

  13. Radiometric, geometric, and image quality assessment of ALOS AVNIR-2 and PRISM sensors

    Science.gov (United States)

    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.

  14. Relative efficiency calibration between two silicon drift detectors performed with a monochromatized X-ray generator over the 0.1-1.5 keV range

    Science.gov (United States)

    Hubert, S.; Boubault, F.

    2018-03-01

    In this article, we present the first X-ray calibration performed over the 0.1-1.5 keV spectral range by means of a soft X-ray Manson source and the monochromator SYMPAX. This monochromator, based on a classical Rowland geometry, presents the novelty to be able to board simultaneously two detectors and move them under vacuum in front of the exit slit of the monochromatizing stage. This provides the great advantage to perform radiometric measurements of the monochromatic X-ray photon flux with one reference detector while calibrating another X-ray detector. To achieve this, at least one secondary standard must be operated with SYMPAX. This paper presents thereby an efficiency transfer experiment between a secondary standard silicon drift detector (SDD), previously calibrated on BESSY II synchrotron Facility, and another one ("unknown" SDD), devoted to be used permanently with SYMPAX. The associated calibration process is described as well as corresponding results. Comparison with calibrated measurements performed at the Physikalisch-Technische Bundesanstalt (PTB) Radiometric Laboratory shows a very good agreement between the secondary standard and the unknown SDD.

  15. Retrieval of effective cloud field parameters from radiometric data

    Science.gov (United States)

    Paulescu, Marius; Badescu, Viorel; Brabec, Marek

    2017-06-01

    Clouds play a key role in establishing the Earth's climate. Real cloud fields are very different and very complex in both morphological and microphysical senses. Consequently, the numerical description of the cloud field is a critical task for accurate climate modeling. This study explores the feasibility of retrieving the effective cloud field parameters (namely the cloud aspect ratio and cloud factor) from systematic radiometric measurements at high frequency (measurement is taken every 15 s). Two different procedures are proposed, evaluated, and discussed with respect to both physical and numerical restrictions. None of the procedures is classified as best; therefore, the specific advantages and weaknesses are discussed. It is shown that the relationship between the cloud shade and point cloudiness computed using the estimated cloud field parameters recovers the typical relationship derived from measurements.

  16. Airborne gamma-ray spectrometer and magnetometer survey: Forsyth quadrangle, Round Up quadrangle, Hardin quadrangle (Montana), Sheridan quadrangle, (Wyoming). Final report

    International Nuclear Information System (INIS)

    1981-01-01

    An airborne combined radiometric and magnetic survey was performed for the Department of Energy (DOE) over the area covered by the Forsyth, Hardin, and Sheridan, and Roundup, 1:250,000 National Topographic Map Series (NTMS), quadrangle maps. The survey was part of DOE's National Uranium Resource Evaluation (NURE) program. Data were collected by a helicopter equipped with a gamma-ray spectrometer with a large crystal volume, and with a high sensitivity proton precession magnetometer. The radiometric system was calibrated at the Walker Field Calibration Pads and the Lake Mead Dynamic Test Range. Data quality was ensured during the survey by daily test flights and equipment checks. Radiometric data were corrected for live time, aircraft and equipment background, cosmic background, atmospheric radon, Compton scatter, and altitude dependence. The corrected data were statistically evaluated, plotted, and contoured to produce anomaly maps based on the radiometric response of individual geological units. The anomalies were interpreted and an interpretation map produced. Volume I contains a description of the systems used in the survey, a discussion of the calibration of the systems, the data collection procedures, the data processing procedures, the data presentation, the interpretation rationale, and the interpretation methodology. A separate Volume II for each quadrangle contains the data displays and the interpretation results

  17. Airborne gamma-ray spectrometer and magnetometer survey: Peoria, Decater, Belleville Quadrangles, (IL). Final report

    International Nuclear Information System (INIS)

    1981-01-01

    An airborne combined radiometric and magnetic survey was performed for the Department of Energy (DOE) over the area covered by the Peoria, Decatur, and Belleville, 1:250,000 National Topographic Map Series (NTMS), quadrangle maps. The survey was part of DOE's National Uranium Resource Evaluation (NURE) program. Data were collected by a helicopter equipped with a gamma-ray spectrometer with a large crystal volume, and with a high sensitivity proton procession magnetometer. The radiometric system was calibrated at the Walker Field Calibration pads and the Lake Mead Dynamic Test Range. Data quality was ensured during the survey by daily test flights and equipment checks. Radiometric data were corrected for live time, aircraft and equipment background, cosmic background, atmospheric radon, Compton scatter, and altitude dependence. The corrected data were statistically evaluated, plotted, and contoured to produce anomaly maps based on the radiometric response of individual geological units. The anomalies were interpreted and an interpretation map produced. Volume I contains a description of the systems used in the survey, a discussion of the calibration of the systems, the data collection procedures, the data processing procedures, the data presentation, the interpretation rationale, and the interpretation methodology. A separate Volume II for each quadrangle contains the data displays and the interpretation results

  18. Radiometric probe design for the measurement of heat flux within a solid rocket motor nozzle

    Science.gov (United States)

    Goldey, Charles L.; Laughlin, William T.; Popper, Leslie A.

    1996-11-01

    Improvements to solid rocket motor (SRM) nozzle designs and material performance is based on the ability to instrument motors during test firings to understand the internal combustion processes and the response of nozzle components to the severe heating environment. Measuring the desired parameters is very difficult because the environment inside of an SRM is extremely severe. Instrumentation can be quickly destroyed if exposed to the internal rocket motor environment. An optical method is under development to quantify the heating of the internal nozzle surface. A radiometric probe designed for measuring the thermal response and material surface recession within a nozzle while simultaneously confining the combustion products has been devised and demonstrated. As part of the probe design, optical fibers lead to calibrated detectors that measure the interior nozzle thermal response. This two color radiometric measurement can be used for a direct determination of the total heat flux impinging on interior nozzle surfaces. This measurement has been demonstrated using a high power CO2 laser to simulate SRM nozzle heating conditions on carbon phenolic and graphite phenolic materials.

  19. RADIOMETRIC TECHNIQUES IN HEAVY MINERAL EXPLORATION AND EXPLOITATION

    NARCIS (Netherlands)

    DEMEIJER, RJ; TANCZOS, IC; STAPEL, C

    1994-01-01

    In recent years the Environmental Research Group of the KVI has been developing a number of radiometric techniques that may be employed in mineral sand exploration. These techniques involve: radiometric fingerprinting for assessing sand provenances and mineralogical composition; thermoluminescence

  20. Multiple-Objective Stepwise Calibration Using Luca

    Science.gov (United States)

    Hay, Lauren E.; Umemoto, Makiko

    2007-01-01

    This report documents Luca (Let us calibrate), a multiple-objective, stepwise, automated procedure for hydrologic model calibration and the associated graphical user interface (GUI). Luca is a wizard-style user-friendly GUI that provides an easy systematic way of building and executing a calibration procedure. The calibration procedure uses the Shuffled Complex Evolution global search algorithm to calibrate any model compiled with the U.S. Geological Survey's Modular Modeling System. This process assures that intermediate and final states of the model are simulated consistently with measured values.

  1. Radiometric and geometric assessment of data from the RapidEye constellation of satellites

    Science.gov (United States)

    Chander, Gyanesh; Haque, Md. Obaidul; Sampath, Aparajithan; Brunn, A.; Trosset, G.; Hoffmann, D.; Roloff, S.; Thiele, M.; Anderson, C.

    2013-01-01

    To monitor land surface processes over a wide range of temporal and spatial scales, it is critical to have coordinated observations of the Earth's surface using imagery acquired from multiple spaceborne imaging sensors. The RapidEye (RE) satellite constellation acquires high-resolution satellite images covering the entire globe within a very short period of time by sensors identical in construction and cross-calibrated to each other. To evaluate the RE high-resolution Multi-spectral Imager (MSI) sensor capabilities, a cross-comparison between the RE constellation of sensors was performed first using image statistics based on large common areas observed over pseudo-invariant calibration sites (PICS) by the sensors and, second, by comparing the on-orbit radiometric calibration temporal trending over a large number of calibration sites. For any spectral band, the individual responses measured by the five satellites of the RE constellation were found to differ B2B) alignment of the image data sets. The position accuracy was assessed by comparing the RE imagery against high-resolution aerial imagery, while the B2B characterization was performed by registering each band against every other band to ensure that the proper band alignment is provided for an image product. The B2B results indicate that the internal alignments of these five RE bands are in agreement, with bands typically registered to within 0.25 pixels of each other or better.

  2. Procedure for calibrating the Technicon Colorimeter I.

    Science.gov (United States)

    Black, J C; Furman, W B

    1975-05-01

    We describe a rapid method for calibrating the Technicon AutoAnalyzer colorimeter I. Test solutions of bromphenol blue are recommended for the calibration, in preference to solutions of potassium dichromate, based on considerations of the instrument's working range and of the stray light characteristics of the associated filters.

  3. State of the art and trends of radiometric methods for measuring the mass per unit area

    International Nuclear Information System (INIS)

    Bernhardt, R.

    1984-01-01

    The determination of the mass per unit area by means of transmission or backscattering methods is one of the traditional radioisotope applications. Microelectronics have essentially contributed to the noticeable progress achieved in the development of radiometric instruments for mass per unit area measurements. The use of microcomputers led to both a reliable solution of the main problem of processing the measured data - the correlation of the mass per unit area value with the detector signal under nonlinear calibration conditions - and a considerable increase in the efficiency of the measuring equipment

  4. SPRT Calibration Uncertainties and Internal Quality Control at a Commercial SPRT Calibration Facility

    Science.gov (United States)

    Wiandt, T. J.

    2008-06-01

    The Hart Scientific Division of the Fluke Corporation operates two accredited standard platinum resistance thermometer (SPRT) calibration facilities, one at the Hart Scientific factory in Utah, USA, and the other at a service facility in Norwich, UK. The US facility is accredited through National Voluntary Laboratory Accreditation Program (NVLAP), and the UK facility is accredited through UKAS. Both provide SPRT calibrations using similar equipment and procedures, and at similar levels of uncertainty. These uncertainties are among the lowest available commercially. To achieve and maintain low uncertainties, it is required that the calibration procedures be thorough and optimized. However, to minimize customer downtime, it is also important that the instruments be calibrated in a timely manner and returned to the customer. Consequently, subjecting the instrument to repeated calibrations or extensive repeated measurements is not a viable approach. Additionally, these laboratories provide SPRT calibration services involving a wide variety of SPRT designs. These designs behave differently, yet predictably, when subjected to calibration measurements. To this end, an evaluation strategy involving both statistical process control and internal consistency measures is utilized to provide confidence in both the instrument calibration and the calibration process. This article describes the calibration facilities, procedure, uncertainty analysis, and internal quality assurance measures employed in the calibration of SPRTs. Data will be reviewed and generalities will be presented. Finally, challenges and considerations for future improvements will be discussed.

  5. A large-scale radiometric micro-quantitative complement fixation test for serum antibody titration

    International Nuclear Information System (INIS)

    Bengali, Z.H.; Levine, P.H.; Das, S.R.

    1980-01-01

    A micro-quantitative complement fixation (CF) procedure based on 51 Cr release is described. The method employs 50% hemolysis as end point and the alternation equation to calculate the amount of complement involved in the hemolytic reaction. Compared to the conventional CF tests, the radiometric procedure described here is very precise and consistently reproducible. Also, since only 3 4-fold dilutions of sera are used for the titration of antibodies over a wide range of concentrations, the test is very concise and is economical to perform. Its format is amenable to automation and computerization. This radioimetric CF procedure is thus most useful for large-scale immunological research and epidemiological surveilance studies. (Auth.)

  6. Tasmanian tin and tungsten granites - their radiometric characteristics

    International Nuclear Information System (INIS)

    Yeates, A.N.

    1982-01-01

    A radiometric survey of Tasmanian granites has shown, with one exception, that tin and tungsten-bearing granites have high radioactivity, largely owing to increased uranium. Many have a high uranium/thorium ratio as well. Radiometric measurements can also delineate different granite types within composite bodies

  7. Evaluation of rapid radiometric method for drug susceptibility testing of Mycobacterium tuberculosis

    International Nuclear Information System (INIS)

    Siddiqi, S.H.; Libonati, J.P.; Middlebrook, G.

    1981-01-01

    A total of 106 isolates of Mycobacterium tuberculosis were tested for drug susceptibility by the conventional 7H11 plate method and by a new rapid radiometric method using special 7H12 liquid medium with 14 C-labeled substrate. Results obtained by the two methods were compared for rapidity, sensitivity, and specificity of the new test method. There was 98% overall agreement between the results obtained by the two methods. Of a total of 424 drug tests, only 8 drug results did not agree, mostly in the case of streptomycin. This new procedure was found to be rapid, with 87% of the tests results reportable within 4 days and 98% reportable within 5 days as compared to the usual 3 weeks required with the conventional indirect susceptibility test method. The results of this preliminary study indicate that the rapid radiometric method seems to have the potential for routine laboratory use and merits further investigations

  8. Training course on radiometric prospecting techniques

    International Nuclear Information System (INIS)

    1979-01-01

    A training course on radiometric prospecting techniques was presented by the Atomic Energy Board in collaboration with the South African Geophysical Association and the Geological Society of South Africa. Various aspects related to uranium prospecting were discussed e.g. the uranium supply and demand position, the basic physics of radioactivity, uranium geochemistry, mineralogy and mobility, the instrumentation and techniques used in uranium exploration, for example, borehole logging, radon emanometry and airborne radiometric surveys and also data processing and interpretation methods

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

    Science.gov (United States)

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

    2008-12-01

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

  10. Determination of molybdenite leaching degree by x-ray radiometric analysis

    International Nuclear Information System (INIS)

    Bibinov, S.A.; Gladyshev, V.P.; Yarmolik, A.S.; Kim, A.Ch.; Sokur, N.P.

    1984-01-01

    A express chemical X-ray radiometric method for determination of leaching degree and analysis of molybdenite products is developed. The method comprises chemical preparation and the following X-ray radiometric determination of molyb bdenum. Total duration of the analysis is 1-1.5 h. The best reproductivity is btained at X-ray radiometric analysis as compared with the chemical one

  11. Radiometric titration of thallium(III) with EDTA

    International Nuclear Information System (INIS)

    Rao, V.R.S.; Pulla Rao, Ch.; Tataiah, G.

    1978-01-01

    Radioactive solutions containing very small amounts of thallium(III) can be determined by radiometric titration using ammonia as hydrolysing agent. Aqueous solution of thallium(I) (both inactive and radioactive) is treated with bromine water till the appearance of the brown colour of bromine, and the solution is warmed to 80 deg C to expel the excess bromine. By this procedure all thallium(I) is quantitatively oxidised to thallium(III). An aqueous solution of ammonia is added to precipitate thallium(III) as thallic oxide. It is then filtered, washed with water to free it from bromide and then dissolved in 2N HCl and the solution is then standardised. 2 ml of this solution is transferred to a 20 ml volumetric flask, 1 ml of radioactive thallium(III) solution to be standardised is added as well as incremental amounts of EDTA solution and mixed thoroughly. Uncomplexed thallium(III) is then precipitated by the addition of an ammonia solution and diluted to 20 ml. Required amount of this mixture is centrifuged. The beta activity of the supernatant aliquot is measured using a GM counter. Quantitative determination of Tl(III) in the range of 1-10 μM can be carried out. The interference of cations such as Au(III), iron(III), Ga(III) can be eliminated by pretreatment of the Tl(III) solution before carrying out radiometric titration. The results obtained are reproducible and accurate to +-3%. (T.I.)

  12. The calibration of portable and airborne gamma-ray spectrometers - theory, problems, and facilities

    International Nuclear Information System (INIS)

    Loevborg, L.

    1984-10-01

    A gamma-ray spectrometer for use in geological exploration possesses four stripping ratios and three window sensitivities which must be determined to make the instrumentation applicable for field assay or airborne measurement of potassium, uranium, and thorium contents in the ground. Survey organizations in many parts of the world perform the instrument calibration using large pads of concrete which simulate a plane ground of known radioelement concentration. Calibration and monitoring trials with twelve facilities in ten countries prove that moisture absorption, radon exhalation, and particle-size effects can offset a radiometric grade assigned to concrete whose aggregate contains an embedded radioactive mineral. These and other calibration problems are discussed from a combined theoretical and practical viewpoint. (author)

  13. UNDERFLIGHT CALIBRATION OF SOHO/CDS AND HINODE/EIS WITH EUNIS-07

    Energy Technology Data Exchange (ETDEWEB)

    Wang Tongjiang; Brosius, Jeffrey W. [Institute for Astrophysics and Computational Sciences (IACS) in the Department of Physics, Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064 (United States); Thomas, Roger J.; Rabin, Douglas M.; Davila, Joseph M. [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States); Young, Peter R. [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Del Zanna, Giulio, E-mail: tongjiang.wang@nasa.gov [DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)

    2011-12-01

    Flights of Goddard Space Flight Center's Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) sounding rocket in 2006 and 2007 provided updated radiometric calibrations for Solar and Heliospheric Observatory/Coronal Diagnostic Spectrometer (SOHO/CDS) and Hinode/Extreme Ultraviolet Imaging Spectrometer (Hinode/EIS). EUNIS carried two independent imaging spectrographs covering wavebands of 300-370 A in first order and 170-205 A in second order. After each flight, end-to-end radiometric calibrations of the rocket payload were carried out in the same facility used for pre-launch calibrations of CDS and EIS. During the 2007 flight, EUNIS, SOHO/CDS, and Hinode/EIS observed the same solar locations, allowing the EUNIS calibrations to be directly applied to both CDS and EIS. The measured CDS NIS 1 line intensities calibrated with the standard (version 4) responsivities with the standard long-term corrections are found to be too low by a factor of 1.5 due to the decrease in responsivity. The EIS calibration update is performed in two ways. One uses the direct calibration transfer of the calibrated EUNIS-07 short wavelength (SW) channel. The other uses the insensitive line pairs, in which one member was observed by the EUNIS-07 long wavelength (LW) channel and the other by EIS in either the LW or SW waveband. Measurements from both methods are in good agreement, and confirm (within the measurement uncertainties) the EIS responsivity measured directly before the instrument's launch. The measurements also suggest that the EIS responsivity decreased by a factor of about 1.2 after the first year of operation (although the size of the measurement uncertainties is comparable to this decrease). The shape of the EIS SW response curve obtained by EUNIS-07 is consistent with the one measured in laboratory prior to launch. The absolute value of the quiet-Sun He II 304 A intensity measured by EUNIS-07 is consistent with the radiance measured by CDS NIS in quiet regions

  14. Calibration and control modules for gamma-ray borehole loggers

    International Nuclear Information System (INIS)

    1983-01-01

    A calibration pad for quantitative evaluation of gamma-ray logs, developed and constructed by CNEA is described. The facility is composed of a set of mineralized modules with which it is intended to reproduce the natural variable conditions found in boreholes drilled for uranium mineral exploration, such as the ore concentration, rock's density and porosity, water content, etc. The facility is able to operate under different radiometric models, as follow: 1) gross-count gamma-ray models; 2) gamma-spectrometer models; 3) neutronic-fission models, and 4) models for determination of magnetic susceptibility, density, neutron-neutron, etc. The gathered information allows the adequate quantitative radiometric evaluation of the ore bodies crossed by exploration holes, and also allows the correlation of gamma-ray logs obtained by different logger-equipments. The paper includes the description of the project development and the standards established for the facility's operation. (M.E.L.) [es

  15. Summary of KOMPSAT-5 Calibration and Validation

    Science.gov (United States)

    Yang, D.; Jeong, H.; Lee, S.; Kim, B.

    2013-12-01

    including pointing, relative and absolute calibration as well as geolocation accuracy determination. The absolute calibration will be accomplished by determining absolute radiometric accuracy using already deployed trihedral corner reflectors on calibration and validation sites located southeast from Ulaanbaatar, Mongolia. To establish a measure for the assess the final image products, geolocation accuracies of image products with different imaging modes will be determined by using deployed point targets and available Digital Terrain Model (DTM), and on different image processing levels. In summary, this paper will present calibration and validation activities performed during the LEOP and IOT of KOMPSAT-5. The methodology and procedure of calibration and validation will be explained as well as its results. Based on the results, the applications of SAR image products on geophysical processes will be also discussed.

  16. A single model procedure for estimating tank calibration equations

    International Nuclear Information System (INIS)

    Liebetrau, A.M.

    1997-10-01

    A fundamental component of any accountability system for nuclear materials is a tank calibration equation that relates the height of liquid in a tank to its volume. Tank volume calibration equations are typically determined from pairs of height and volume measurements taken in a series of calibration runs. After raw calibration data are standardized to a fixed set of reference conditions, the calibration equation is typically fit by dividing the data into several segments--corresponding to regions in the tank--and independently fitting the data for each segment. The estimates obtained for individual segments must then be combined to obtain an estimate of the entire calibration function. This process is tedious and time-consuming. Moreover, uncertainty estimates may be misleading because it is difficult to properly model run-to-run variability and between-segment correlation. In this paper, the authors describe a model whose parameters can be estimated simultaneously for all segments of the calibration data, thereby eliminating the need for segment-by-segment estimation. The essence of the proposed model is to define a suitable polynomial to fit to each segment and then extend its definition to the domain of the entire calibration function, so that it (the entire calibration function) can be expressed as the sum of these extended polynomials. The model provides defensible estimates of between-run variability and yields a proper treatment of between-segment correlations. A portable software package, called TANCS, has been developed to facilitate the acquisition, standardization, and analysis of tank calibration data. The TANCS package was used for the calculations in an example presented to illustrate the unified modeling approach described in this paper. With TANCS, a trial calibration function can be estimated and evaluated in a matter of minutes

  17. Ultra-portable field transfer radiometer for vicarious calibration of earth imaging sensors

    Science.gov (United States)

    Thome, Kurtis; Wenny, Brian; Anderson, Nikolaus; McCorkel, Joel; Czapla-Myers, Jeffrey; Biggar, Stuart

    2018-06-01

    A small portable transfer radiometer has been developed as part of an effort to ensure the quality of upwelling radiance from test sites used for vicarious calibration in the solar reflective. The test sites are used to predict top-of-atmosphere reflectance relying on ground-based measurements of the atmosphere and surface. The portable transfer radiometer is designed for one-person operation for on-site field calibration of instrumentation used to determine ground-leaving radiance. The current work describes the detector- and source-based radiometric calibration of the transfer radiometer highlighting the expected accuracy and SI-traceability. The results indicate differences between the detector-based and source-based results greater than the combined uncertainties of the approaches. Results from recent field deployments of the transfer radiometer using a solar radiation based calibration agree with the source-based laboratory calibration within the combined uncertainties of the methods. The detector-based results show a significant difference to the solar-based calibration. The source-based calibration is used as the basis for a radiance-based calibration of the Landsat-8 Operational Land Imager that agrees with the OLI calibration to within the uncertainties of the methods.

  18. Cross calibration of the Landsat-7 ETM+ and EO-1 ALI sensor

    Science.gov (United States)

    Chander, G.; Meyer, D.J.; Helder, D.L.

    2004-01-01

    As part of the Earth Observer 1 (EO-1) Mission, the Advanced Land Imager (ALI) demonstrates a potential technological direction for Landsat Data Continuity Missions. To evaluate ALI's capabilities in this role, a cross-calibration methodology has been developed using image pairs from the Landsat-7 (L7) Enhanced Thematic Mapper Plus (ETM+) and EO-1 (ALI) to verify the radiometric calibration of ALI with respect to the well-calibrated L7 ETM+ sensor. Results have been obtained using two different approaches. The first approach involves calibration of nearly simultaneous surface observations based on image statistics from areas observed simultaneously by the two sensors. The second approach uses vicarious calibration techniques to compare the predicted top-of-atmosphere radiance derived from ground reference data collected during the overpass to the measured radiance obtained from the sensor. The results indicate that the relative sensor chip assemblies gains agree with the ETM+ visible and near-infrared bands to within 2% and the shortwave infrared bands to within 4%.

  19. Measurement of particle emission in automobil exhaust - application of continuous radiometric aerosol measurement to the emission of diesel engines

    International Nuclear Information System (INIS)

    Krasenbrink, A.; Georgi, B.

    1989-01-01

    The well-known method of measuring continuously dust by β-absorption is transferred to the problem of particle emission in automobile exhaust. With two similar dust-monitors FH62 having different sampling air flow rates and two low-pressure impactors the reliability of radiometric mass determination was verified. First static experiments with diesel soot showed the necessity of a dilution system, a new mass calibration with regard to the changed β-absorptivity and a quicker calculation of concentration for realtime measurements. (orig.) [de

  20. Evaluation of element migration from food plastic packagings into simulated solutions using radiometric method

    International Nuclear Information System (INIS)

    Soares, Eufemia Paez; Saiki, Mitiko; Wiebeck, Helio

    2005-01-01

    In the present study a radiometric method was established to determine the migration of elements from food plastic packagings to a simulated acetic acid solution. This radiometric method consisted of irradiating plastic samples with neutrons at IEA-R1 nuclear reactor for a period of 16 hours under a neutron flux of 10 12 n cm -2 s -1 and, then to expose them to the element migration into a simulated solution. The radioactivity of the activated elements transferred to the solutions was measured to evaluate the migration. The experimental conditions were: time of exposure of 10 days at 40 deg C and 3% acetic acid solution was used as simulated solution, according to the procedure established by the National Agency of Sanitary Monitoring (ANVISA). The migration study was applied for plastic samples from soft drink and juice packagings. The results obtained indicated the migration of elements Co, Cr and Sb. The advantage of this methodology was no need to analyse the blank of simulantes, as well as the use of high purity simulated solutions. Besides, the method allows to evaluate the migration of the elements into the food content instead of simulated solution. The detention limits indicated high sensitivity of the radiometric method. (author)

  1. Calibration procedure for a potato crop growth model using information from across Europe

    DEFF Research Database (Denmark)

    Heidmann, Tove; Tofteng, Charlotte; Abrahamsen, Per

    2008-01-01

    for adaptation of the Daisy model to new potato varieties or for the improvement of the existing parameter set. The procedure is then, as a starting point, to focus the calibration process on the recommended list of parameters to change. We demonstrate this approach by showing the procedure for recalibrating...... three varieties using all relevant data from the sites. We believe these new parameterisations to be more robust, because they indirectly were based on information from the six different sites. We claim that this procedure combines both local and specific modeller expertise in a way that results in more......In the FertOrgaNic EU project, 3 years of field experiments with drip irrigation and fertigation were carried out at six different sites across Europe, involving seven different varieties of potato. The Daisy model, which simulates plant growth together with water and nitrogen dynamics, was used...

  2. Radiometric well logging instruments

    International Nuclear Information System (INIS)

    Davydov, A.V.

    1975-01-01

    The technical properties of well instruments for radioactive logging used in the radiometric logging complexes PKS-1000-1 (''Sond-1'') and PRKS-2 (''Vitok-2'') are described. The main features of the electric circuit of the measuring channels are given

  3. Calibration procedures of area monitors in terms of the Ambient Dose Equivalent H*(10), for gamma, x-ray radiation fields

    International Nuclear Information System (INIS)

    Dieguez Davila, L.E.

    1998-01-01

    In the present thesis procedures for calibrating portable survey meters in terms of the new ICRU quantities H*(10) ambient dose equivalent are discussed. Also the remendations of International Comission on Radiation Protection in their report ICRP 60 that inludes the operational magnitudes that the International Comission of Radiation Units proposed for calibrating area monitors

  4. The radiometric industries of the countries of the European Community

    International Nuclear Information System (INIS)

    Roeper, Burkhardt

    1975-01-01

    The economic development of the radiometric industries in the EEC and the USA since 1960 is studied on the basis of sales statistics. The study covers the supply and the use of radioisotopes, the application of radiometric techniques, the scope and the development of the foreign trade as well as the structure of the firms concerned. The future need for radiometric apparatus is estimated as regards radiation protection, laboratories, industry, nuclear power plants and medicine

  5. Single-source gamma radiation procedures for improved calibration and measurements in porous media

    International Nuclear Information System (INIS)

    Oostrom, M.; Hofstee, C.; Dane, H.; Lenhard, R.J.

    1998-01-01

    When dual-energy gamma radiation systems are employed for measurements in porous media, count rates from both sources are often used to compute parameter values. However, for several applications, the count rates of just one source are insufficient. These applications include the determination of volumetric liquid content values in two-liquid systems and salt concentration values in water-saturated porous media. Single-energy gamma radiation procedures for three applications are described in this paper. Through an error analysis, single-source procedures are shown to reduce the probable error in the determinations considerably. Example calculations and simple column experiments were conducted for each application to compare the performance of the new single-source and standard dual-source methods. In all cases, the single-source methods provided more reliable data than the traditional dual-source methods. In addition, a single-source calibration procedure is proposed to determine incident count rates indirectly. This procedure, which requires packing under saturated conditions, can be used in all single- and dual-source applications and yields accurate porosity and dry bulk density values

  6. Experiences of a secondary laboratory of dosimetric calibration from the radiation protection and hygiene center CPHR in its first year of work and the procedures for quality assessment used in the calibration and quality control service

    International Nuclear Information System (INIS)

    Morales, J.A.; Campa, R.; Jova Sed, L.

    1996-01-01

    Experiences of a secondary laboratory of dosimetric calibration from the Radiation Protection and Hygiene Center (CPHR) in first year of work and the procedures for quality assessment used in the calibration and quality control service of radiotherapeutic equipment. For the yield calibration of the calibrated sources an ionometric method was used using ionizing chambers coupled to electrometers. Those determination were based on dosimetric American Association of Physicists in Medicine (AAPM)

  7. Rotary mode system initial instrument calibration

    International Nuclear Information System (INIS)

    Johns, B.R.

    1994-01-01

    The attached report contains the vendor calibration procedures used for the initial instrument calibration of the rotary core sampling equipment. The procedures are from approved vendor information files

  8. Radiometric report for a blast furnace tracing with radioactive isotopes

    International Nuclear Information System (INIS)

    Tanase, G.; Tanase, M.

    1995-01-01

    One of the methods to monitor refractory wall of blast furnace is its tracing with radioactive isotopes. The tracer isotope can be detected by two ways: the external dosimetric measurement at the armour of the blast furnace and/or the radiometric measurement of the iron sample charge by charge. Any change in radiometric situation of tracer radioisotope is recorded in a radiometric report. This paper presents an original concept of radiometric report based upon PARADOX and CORELDRAW soft kits. Their advantage are: quick and easy changes, easy recording of current radioactivity of tracer isotope, short history of changes, visual mapping of the tracer isotope and others. In this way we monitored 6 blast furnaces and more than 180 radioactive sources

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

    International Nuclear Information System (INIS)

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

    1980-01-01

    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

  10. Radioactive concrete sources at IRD/CNEN, Brazil, for calibration of uranium exploration and environmental field instruments

    International Nuclear Information System (INIS)

    Barreto, P.M.C.; Campos, C.A.; Malheiros, T.M.M.; Locborg, L.

    1988-01-01

    A radiometric calibration system consisting of eight radioactive concrete sources was constructed at the Institute of Radiation Protection and Dosimetry (IRD) of the Brazilian Nuclear Energy Commission (CNEN). These sources, stimulating rock outcrops, are available to geophysicists interested in uranium explotation and scientists working with natural radioactivity in environmental research. The sources are of cylindrical shape with 3m diameter and 0.5m thickness weighing approximately 7.5 tonnes each. They are disposed in a circle having in its centre a 4m diameter water pond for cosmi-ray and instrument noise corrections. Uranium, thorium and potassium ores were added to the concrete under such conditions as to achieve perfect homogenization. One hundred and four samples were collected and analysed by eight laboratories. In addition, in-situ radiometric grade determination were performed with calibrated instruments resulting a total of 2.100 determinations of U, Th and K, from which the reference values were assigned to each source. With this system, it is possible to calculate sensitivity constants and stripping ratios for portable gamma-ray spectrometers. It also provides excellent means for the calibration of radiation detectors used in environmental monitoring, in which humidity, temperature and omni-directional gamma flux, similar to the natural environmental, are simulated. (author) [pt

  11. Improving the Ar I and II branching ratio calibration method: Monte Carlo simulations of effects from photon scattering/reflecting in hollow cathodes

    Science.gov (United States)

    Lawler, J. E.; Den Hartog, E. A.

    2018-03-01

    The Ar I and II branching ratio calibration method is discussed with the goal of improving the technique. This method of establishing a relative radiometric calibration is important in ongoing research to improve atomic transition probabilities for quantitative spectroscopy in astrophysics and other fields. Specific suggestions are presented along with Monte Carlo simulations of wavelength dependent effects from scattering/reflecting of photons in a hollow cathode.

  12. Energy calibration issues in nuclear resonant vibrational spectroscopy: observing small spectral shifts and making fast calibrations.

    Science.gov (United States)

    Wang, Hongxin; Yoda, Yoshitaka; Dong, Weibing; Huang, Songping D

    2013-09-01

    The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4 keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) an in situ calibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3 meV energy shift between the 100%-(57)Fe-enriched [Fe4S4Cl4](=) and 10%-(57)Fe and 90%-(54)Fe labeled [Fe4S4Cl4](=) has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3-4 h to about 30 min. Although the quick-switching calibration is not in situ, it is suitable for normal NRVS measurements.

  13. Application of microcomputer to X-ray radiometric ore separation

    International Nuclear Information System (INIS)

    Neverov, A.D.; Aleksandrov, P.S.; Kotler, N.I.

    1988-01-01

    The practical use of microcomputers as universal means for converting information for solving applied problems of X-ray radiometric ore separation method is considered. Laboratory tests of two metals - tungsten and tin manifested high efficiency of the developed system. X-ray radiometric separator software is developed

  14. GOES-R Advanced Baseline Imager: spectral response functions and radiometric biases with the NPP Visible Infrared Imaging Radiometer Suite evaluated for desert calibration sites.

    Science.gov (United States)

    Pearlman, Aaron; Pogorzala, David; Cao, Changyong

    2013-11-01

    The Advanced Baseline Imager (ABI), which will be launched in late 2015 on the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellite R-series satellite, will be evaluated in terms of its data quality postlaunch through comparisons with other satellite sensors such as the recently launched Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership satellite. The ABI has completed much of its prelaunch characterization and its developers have generated and released its channel spectral response functions (response versus wavelength). Using these responses and constraining a radiative transfer model with ground reflectance, aerosol, and water vapor measurements, we simulate observed top of atmosphere (TOA) reflectances for analogous visible and near infrared channels of the VIIRS and ABI sensors at the Sonoran Desert and White Sands National Monument sites and calculate the radiometric biases and their uncertainties. We also calculate sensor TOA reflectances using aircraft hyperspectral data from the Airborne Visible/Infrared Imaging Spectrometer to validate the uncertainties in several of the ABI and VIIRS channels and discuss the potential for validating the others. Once on-orbit, calibration scientists can use these biases to ensure ABI data quality and consistency to support the numerical weather prediction community and other data users. They can also use the results for ABI or VIIRS anomaly detection and resolution.

  15. Calibration of triaxial fluxgate gradiometer

    International Nuclear Information System (INIS)

    Vcelak, Jan

    2006-01-01

    The description of simple and fast calibration procedures used for double-probe triaxial fluxgate gradiometer is provided in this paper. The calibration procedure consists of three basic steps. In the first step both probes are calibrated independently in order to reach constant total field reading in every position. Both probes are numerically aligned in the second step in order that the gradient reading is zero in homogenous magnetic field. The third step consists of periodic drift calibration during measurement. The results and detailed description of each calibration step are presented and discussed in the paper. The gradiometer is finally verified during the detection of the metal object in the measuring grid

  16. Radiometric Correction of Close-Range Spectral Image Blocks Captured Using an Unmanned Aerial Vehicle with a Radiometric Block Adjustment

    Directory of Open Access Journals (Sweden)

    Eija Honkavaara

    2018-02-01

    Full Text Available Unmanned airborne vehicles (UAV equipped with novel, miniaturized, 2D frame format hyper- and multispectral cameras make it possible to conduct remote sensing measurements cost-efficiently, with greater accuracy and detail. In the mapping process, the area of interest is covered by multiple, overlapping, small-format 2D images, which provide redundant information about the object. Radiometric correction of spectral image data is important for eliminating any external disturbance from the captured data. Corrections should include sensor, atmosphere and view/illumination geometry (bidirectional reflectance distribution function—BRDF related disturbances. An additional complication is that UAV remote sensing campaigns are often carried out under difficult conditions, with varying illumination conditions and cloudiness. We have developed a global optimization approach for the radiometric correction of UAV image blocks, a radiometric block adjustment. The objective of this study was to implement and assess a combined adjustment approach, including comprehensive consideration of weighting of various observations. An empirical study was carried out using imagery captured using a hyperspectral 2D frame format camera of winter wheat crops. The dataset included four separate flights captured during a 2.5 h time period under sunny weather conditions. As outputs, we calculated orthophoto mosaics using the most nadir images and sampled multiple-view hyperspectral spectra for vegetation sample points utilizing multiple images in the dataset. The method provided an automated tool for radiometric correction, compensating for efficiently radiometric disturbances in the images. The global homogeneity factor improved from 12–16% to 4–6% with the corrections, and a reduction in disturbances could be observed in the spectra of the object points sampled from multiple overlapping images. Residuals in the grey and white reflectance panels were less than 5% of the

  17. Calibrated Full-Waveform Airborne Laser Scanning for 3D Object Segmentation

    Directory of Open Access Journals (Sweden)

    Fanar M. Abed

    2014-05-01

    Full Text Available Segmentation of urban features is considered a major research challenge in the fields of photogrammetry and remote sensing. However, the dense datasets now readily available through airborne laser scanning (ALS offer increased potential for 3D object segmentation. Such potential is further augmented by the availability of full-waveform (FWF ALS data. FWF ALS has demonstrated enhanced performance in segmentation and classification through the additional physical observables which can be provided alongside standard geometric information. However, use of FWF information is not recommended without prior radiometric calibration, taking into account all parameters affecting the backscatter energy. This paper reports the implementation of a radiometric calibration workflow for FWF ALS data, and demonstrates how the resultant FWF information can be used to improve segmentation of an urban area. The developed segmentation algorithm presents a novel approach which uses the calibrated backscatter cross-section as a weighting function to estimate the segmentation similarity measure. The normal vector and the local Euclidian distance are used as criteria to segment the point clouds through a region growing approach. The paper demonstrates the potential to enhance 3D object segmentation in urban areas by integrating the FWF physical backscattered energy alongside geometric information. The method is demonstrated through application to an interest area sampled from a relatively dense FWF ALS dataset. The results are assessed through comparison to those delivered from utilising only geometric information. Validation against a manual segmentation demonstrates a successful automatic implementation, achieving a segmentation accuracy of 82%, and out-performs a purely geometric approach.

  18. ORNL calibrations facility

    International Nuclear Information System (INIS)

    Berger, C.D.; Gupton, E.D.; Lane, B.H.; Miller, J.H.; Nichols, S.W.

    1982-08-01

    The ORNL Calibrations Facility is operated by the Instrumentation Group of the Industrial Safety and Applied Health Physics Division. Its primary purpose is to maintain radiation calibration standards for calibration of ORNL health physics instruments and personnel dosimeters. This report includes a discussion of the radioactive sources and ancillary equipment in use and a step-by-step procedure for calibration of those survey instruments and personnel dosimeters in routine use at ORNL

  19. Airborne gamma-ray spectrometer and magnetometer survey: Lund quadrangle, Ely quadrangle, Nevada. Volume I. Final report

    International Nuclear Information System (INIS)

    1980-01-01

    An airborne combined radiometric and magnetic survey was performed for the Department of Energy (DOE) over the area covered by the Ely and Lund 1:250,000 National Topographic Map Series (NTMS quadrangle maps). The survey was part of DOE's National Uranium Resource Evaluation (NURE) Aerial Radiometric Reconnaissance program. Data were collected by a helicopter equipped with a gamma-ray spectrometer having a large crystal volume, and a high sensitivity proton precession magnetometer. The radiometric system was calibrated at the Walker Field Calibration pads and the Lake Mead Dynamic Test range. Data quality was ensured during the survey by daily test flights and equipment checks. Radiometric data were corrected for live time, aircraft and equipment background, cosmic background, atmospheric radon, Compton scatter, and altitude dependence. The corrected data were statistically evaluated, plotted, and contoured to produce anomaly maps based on the radiometric response of individual geological units. The maps were interpreted and an anomaly interpretation map produced. Volume I contains a description of the systems used in the survey, a discussion of the calibration of the systems, the data processing procedures, the data display format, the interpretation rationale, and interpretation methodology. Volume II contains the data displays for a quadrangle and the interpretation results

  20. Calibration procedure for thermoluminescent dosemeters in water absorbed doses for Iridium-192 high dose rate sources

    International Nuclear Information System (INIS)

    Reyes Cac, Franky Eduardo

    2004-10-01

    Thermoluminescent dosimeters are used in brachytherapy services quality assurance programs, with the aim of guaranteeing the correct radiation dose supplied to cancer patients, as well as with the purpose of evaluating new clinical procedures. This work describes a methodology for thermoluminescent dosimeters calibration in terms of absorbed dose to water for 192 Ir high dose rate sources. The reference dose used is measured with an ionization chamber previously calibrated for 192 Ir energy quality, applying the methodology proposed by Toelli. This methodology aims to standardizing the procedure, in a similar form to that used for external radiotherapy. The work evolves the adaptation of the TRS-277 Code of the International Atomic Energy Agency, for small and big cavities, through the introduction for non-uniform experimental factor, for the absorbed dose in the neighborhood of small brachytherapy sources. In order to simulate a water medium around the source during the experimental work, an acrylic phantom was used. It guarantees the reproducibility of the ionization chamber and the thermoluminescent dosimeter's location in relation to the radiation source. The values obtained with the ionization chamber and the thermoluminescent dosimeters, exposed to a 192 Ir high dose rate source, were compared and correction factors for different source-detector distances were determined for the thermoluminescent dosimeters. A numeric function was generated relating the correction factors and the source-detector distance. These correction factors are in fact the thermoluminescent dosimeter calibration factors for the 192 Ir source considered. As a possible application of this calibration methodology for thermoluminescent dosimeters, a practical range of source-detector distances is proposed for quality control of 192 Ir high dose rate sources. (author)

  1. Synthetic samples as imitators of elements composition for calibration in nuclear-physical methods of analysis

    International Nuclear Information System (INIS)

    Lakhov, V.M.; Gerling, V.Eh.; Il'ina, L.K.; Trojnina, G.G.; Galisheva, Eh.P.

    1987-01-01

    The papers on the problems of developing and application of synthetic standard samples (SS), imitating the substance and material (rocks, ores) element composition aimed at calibration, testing and certification of the equipment as well as check on the results of neutron-activation, X-ray spectral, X-ray radiometric, X-ray fluorescence and other nuclear-physical methods of analysis, are reviewed. It is shown that choice of SS preparation method is defined by peculiarities of analysis method for which calibration SS is designed. Experience in application of SS imitators of element composition in interlaboratory comparisons testifies to potential application of synthetic SS for calibration in different methods of analysis including, nuclear-physical ones

  2. Calibrating nacelle lidars

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, M.

    2013-01-15

    Nacelle mounted, forward looking wind lidars are beginning to be used to provide reference wind speed measurements for the power performance testing of wind turbines. In such applications, a formal calibration procedure with a corresponding uncertainty assessment will be necessary. This report presents four concepts for performing such a nacelle lidar calibration. Of the four methods, two are found to be immediately relevant and are pursued in some detail. The first of these is a line of sight calibration method in which both lines of sight (for a two beam lidar) are individually calibrated by accurately aligning the beam to pass close to a reference wind speed sensor. A testing procedure is presented, reporting requirements outlined and the uncertainty of the method analysed. It is seen that the main limitation of the line of sight calibration method is the time required to obtain a representative distribution of radial wind speeds. An alternative method is to place the nacelle lidar on the ground and incline the beams upwards to bisect a mast equipped with reference instrumentation at a known height and range. This method will be easier and faster to implement and execute but the beam inclination introduces extra uncertainties. A procedure for conducting such a calibration is presented and initial indications of the uncertainties given. A discussion of the merits and weaknesses of the two methods is given together with some proposals for the next important steps to be taken in this work. (Author)

  3. Observatory Magnetometer In-Situ Calibration

    Directory of Open Access Journals (Sweden)

    A Marusenkov

    2011-07-01

    Full Text Available An experimental validation of the in-situ calibration procedure, which allows estimating parameters of observatory magnetometers (scale factors, sensor misalignment without its operation interruption, is presented. In order to control the validity of the procedure, the records provided by two magnetometers calibrated independently in a coil system have been processed. The in-situ estimations of the parameters are in very good agreement with the values provided by the coil system calibration.

  4. Calibration Of Partial-Pressure-Of-Oxygen Sensors

    Science.gov (United States)

    Yount, David W.; Heronimus, Kevin

    1995-01-01

    Report and analysis of, and discussion of improvements in, procedure for calibrating partial-pressure-of-oxygen sensors to satisfy Spacelab calibration requirements released. Sensors exhibit fast drift, which results in short calibration period not suitable for Spacelab. By assessing complete process of determining total drift range available, calibration procedure modified to eliminate errors and still satisfy requirements without compromising integrity of system.

  5. A Novel Nonintrusive Method to Resolve the Thermal Dome Effect of Pyranometers: Radiometric Calibration and Implications

    Science.gov (United States)

    Ji. Q.; Tsay, S.-C.; Lau, K. M.; Hansell, R. A.; Butler, J. J.; Cooper, J. W.

    2011-01-01

    Traditionally the calibration equation for pyranometers assumes that the measured solar irradiance is solely proportional to the thermopile s output voltage; therefore, only a single calibration factor is derived. This causes additional measurement uncertainties because it does not capture sufficient information to correctly account for a pyranometer s thermal effect. In our updated calibration equation, temperatures from the pyranometer's dome and case are incorporated to describe the instrument's thermal behavior, and a new set of calibration constants are determined, thereby reducing measurement uncertainties. In this paper, we demonstrate why a pyranometer's uncertainty using the traditional calibration equation is always larger than a few percent, but with the new approach can become much less than 1% after the thermal issue is resolved. The highlighted calibration results are based on NIST traceable light sources under controlled laboratory conditions. The significance of the new approach lends itself to not only avoiding the uncertainty caused by a pyranometer's thermal effect but also the opportunity to better isolate and characterize other instrumental artifacts, such as angular response and nonlinearity of the thermopile, to further reduce additional uncertainties. We also discuss some of the implications, including an example of how the thermal issue can potentially impact climate studies by evaluating aerosol s direct radiative effect using field measurements with and without considering the pyranometer s thermal effect. The results of radiative transfer model simulation show that a pyranometer s thermal effect on solar irradiance measurements at the surface can be translated into a significant alteration of the calculated distribution of solar energy inside the column atmosphere.

  6. Panay carborne radiometric and geochemical surveys

    International Nuclear Information System (INIS)

    Santos, G. Jr.

    1981-09-01

    A carborne radiometric survey and stream sediments collection were conducted in Panay and Guimaras Islands. An area in Nabas, Aklan, situated in the northwestern tip of Panay (Buruanga Peninsula) which indicated 2 to 3 times above background radioactivity was delineated. Uranium content in the stream sediment samples collected from Buruanga Peninsula was generally higher than those obtained in other parts of the island. Radioactivity measurements and uranium content in stream sediments were found to be within background levels. It is recommended that follow-up radiometric and geochemical surveys be undertaken in Buruanga Peninsula and additional stream sediments samples be collected in Panay to achieve better sampling density and coverage. (author)

  7. Project of an integrated calibration laboratory of instruments at IPEN

    International Nuclear Information System (INIS)

    Barros, Gustavo Adolfo San Jose

    2009-01-01

    The Calibration Laboratory of Instruments of Instituto de Pesquisas Energeticas e Nucleares offers calibration services of radiation detectors used in radioprotection, diagnostic radiology and radiotherapy, for IPEN and for external facilities (public and private). One part of its facilities is located in the main building, along with other laboratories and study rooms, and another part in an isolated building called Bunker. For the optimization, modernization and specially the safety, the laboratories in the main building shall be transferred to an isolated place. In this work, a project of an integrated laboratory for calibration of instruments was developed, and it will be an expansion of the current Calibration Laboratory of Instruments of IPEN. Therefore, a series of radiometric monitoring of the chosen localization of the future laboratory was realized, and all staff needs (dimensions and disposition of the study rooms and laboratories) were defined. In this project, the laboratories with X ray equipment, alpha and beta radiation sources were located at an isolated part of the building, and the wall shielding was determined, depending on the use of each laboratory. (author)

  8. Investigations with a simplified method for radiometric determination of vitamin B12 in body fluids and feeding stuffs

    International Nuclear Information System (INIS)

    Menke, K.H.; Kohlberger, G.; Koenemund, A.

    1979-01-01

    A modified method for radiometrical determination of vitamin B 12 is described, which in difference to the known methods is based on measurement of free B 12 after absorption to albumin-coated charcoal instead of measurement of intrinsic factor B 12 -complex. The conditions for extraction from serum, milk, rumen-liquor and urine have been investigated and the effect of pH on IF-B 12 -binding in presence of these body fluids examined. Parallel microbiological determinations (O.m.- and L.1.-test) were in good correlation (r = 0,93-0,97) to radiometrically determined B 12 -contents in milk and rumen-liquor, but not to that in serum of dairy cows (r = 0,54-0,82). The analytical procedures are given in detail. (orig.) [de

  9. Calibration procedures for mammography dosemeters in Poland

    International Nuclear Information System (INIS)

    Gwiazdowska, B.; Ulkowski, P.; Tolwinski, J.; Bulski, W.

    2002-01-01

    Breast cancer is the most frequent tumour in women and the effectiveness of the treatment depends dramatically on the early detection of the disease. That is the reason why in Poland the mammography control examinations are strongly supported by the Centre of Oncology. In Poland there are over 400 mammography units which account for about 300,000 examinations per year. An investigation performed by the Medical Physics Department of the Centre of Oncology in Warsaw at about 100 mammography facilities proved that in most cases the doses absorbed by the patients could be reduced without decrease of image quality. This is one of the reasons why the Polish Secondary Standard Dosimetry Laboratory (SSDL) dealing mainly with calibration of radiotherapy dosemeters is extending its activities and therefore new facilities and equipment adapted for calibration of mammographic dosemeters have been installed. The mammography dosimetry calibration equipment is permanently installed in the same laboratory room where the radiotherapy dosemeters are calibrated. A base of a mammography unit no longer in clinical use, together with its movable system has been adapted to handle ionization chamber holders. An X-ray tube with a 50 kV high frequency generator was also installed. The tube, a Varian type OEG-50-2, (designed for laboratory applications) with molybdenum anode of an anode angle 23,7 deg. and with a large focus, effective size approximately 5 mm 2 , has an inherent filtration of 0,25 mm beryllium. It is installed in a housing with 2mm lead shielding; a cone shaped beam is formed by a system of three collimators

  10. Validation of an efficiency calibration procedure for a coaxial n-type and a well-type HPGe detector used for the measurement of environmental radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Morera-Gómez, Yasser, E-mail: ymore24@gamail.com [Centro de Estudios Ambientales de Cienfuegos, AP 5. Ciudad Nuclear, CP 59350 Cienfuegos (Cuba); Departamento de Química y Edafología, Universidad de Navarra, Irunlarrea No 1, Pamplona 31009, Navarra (Spain); Cartas-Aguila, Héctor A.; Alonso-Hernández, Carlos M.; Nuñez-Duartes, Carlos [Centro de Estudios Ambientales de Cienfuegos, AP 5. Ciudad Nuclear, CP 59350 Cienfuegos (Cuba)

    2016-05-11

    To obtain reliable measurements of the environmental radionuclide activity using HPGe (High Purity Germanium) detectors, the knowledge of the absolute peak efficiency is required. This work presents a practical procedure for efficiency calibration of a coaxial n-type and a well-type HPGe detector using experimental and Monte Carlo simulations methods. The method was performed in an energy range from 40 to 1460 keV and it can be used for both, solid and liquid environmental samples. The calibration was initially verified measuring several reference materials provided by the IAEA (International Atomic Energy Agency). Finally, through the participation in two Proficiency Tests organized by IAEA for the members of the ALMERA network (Analytical Laboratories for the Measurement of Environmental Radioactivity) the validity of the developed procedure was confirmed. The validation also showed that measurement of {sup 226}Ra should be conducted using coaxial n-type HPGe detector in order to minimize the true coincidence summing effect. - Highlights: • An efficiency calibration for a coaxial and a well-type HPGe detector was performed. • The calibration was made using experimental and Monte Carlo simulations methods. • The procedure was verified measuring several reference materials provided by IAEA. • Calibrations were validated through the participation in 2 ALMERA Proficiency Tests.

  11. Calibration of thermoluminiscent materials

    International Nuclear Information System (INIS)

    Bos, A.J.J.

    1989-07-01

    In this report the relation between exposure and absorbed radiation dose in various materials is represented, on the base of recent data. With the help of this a calibration procedure for thermoluminescent materials, adapted to the IRI radiation standard is still the exposure in rontgen. In switching to the air kerma standard the calibration procedure will have to be adapted. (author). 6 refs.; 4 tabs

  12. Statistical techniques applied to aerial radiometric surveys (STAARS): series introduction and the principal-components-analysis method

    International Nuclear Information System (INIS)

    Pirkle, F.L.

    1981-04-01

    STAARS is a new series which is being published to disseminate information concerning statistical procedures for interpreting aerial radiometric data. The application of a particular data interpretation technique to geologic understanding for delineating regions favorable to uranium deposition is the primary concern of STAARS. Statements concerning the utility of a technique on aerial reconnaissance data as well as detailed aerial survey data will be included

  13. Calibration Procedures in Mid Format Camera Setups

    Science.gov (United States)

    Pivnicka, F.; Kemper, G.; Geissler, S.

    2012-07-01

    A growing number of mid-format cameras are used for aerial surveying projects. To achieve a reliable and geometrically precise result also in the photogrammetric workflow, awareness on the sensitive parts is important. The use of direct referencing systems (GPS/IMU), the mounting on a stabilizing camera platform and the specific values of the mid format camera make a professional setup with various calibration and misalignment operations necessary. An important part is to have a proper camera calibration. Using aerial images over a well designed test field with 3D structures and/or different flight altitudes enable the determination of calibration values in Bingo software. It will be demonstrated how such a calibration can be performed. The direct referencing device must be mounted in a solid and reliable way to the camera. Beside the mechanical work especially in mounting the camera beside the IMU, 2 lever arms have to be measured in mm accuracy. Important are the lever arms from the GPS Antenna to the IMU's calibrated centre and also the lever arm from the IMU centre to the Camera projection centre. In fact, the measurement with a total station is not a difficult task but the definition of the right centres and the need for using rotation matrices can cause serious accuracy problems. The benefit of small and medium format cameras is that also smaller aircrafts can be used. Like that, a gyro bases stabilized platform is recommended. This causes, that the IMU must be mounted beside the camera on the stabilizer. The advantage is, that the IMU can be used to control the platform, the problematic thing is, that the IMU to GPS antenna lever arm is floating. In fact we have to deal with an additional data stream, the values of the movement of the stabiliser to correct the floating lever arm distances. If the post-processing of the GPS-IMU data by taking the floating levers into account, delivers an expected result, the lever arms between IMU and camera can be applied

  14. A simple radiometric in vitro assay for acetylcholinesterase inhibitors

    International Nuclear Information System (INIS)

    Guilarte, T.R.; Burns, H.D.; Dannals, R.F.; Wagner, H.N. Jr.

    1983-01-01

    A radiometric method for screening acetylcholinesterase inhibitors has been described. The method is based on the production of [ 14 C]carbon dioxide from the hydrolysis of acetylcholine. The inhibitory concentration at 50% (IC50) values for several known acetylcholinesterase inhibitors were in agreement with literature values. The new radiometric method is simple, inexpensive, and has the potential for automation

  15. Automation of radiometric testing

    International Nuclear Information System (INIS)

    Chekalin, A.S.; Temnik, A.K.; Butakova, G.E.; Goncharov, V.I.

    1983-01-01

    The main prerequisites for creation of automatic systems of radiometric testing as the means to increase the testing objectivity and quality have been considered, principles of their design being developed. The operating system is described for testing complex configuration products using RD-10R gamma flow detector as a sensor of initial information

  16. Report on International Spaceborne Imaging Spectroscopy Technical Committee Calibration and Validation Workshop, National Environment Research Council Field Spectroscopy Facility, University of Edinburgh

    Science.gov (United States)

    Ong, C,; Mueller, A.; Thome, K.; Bachmann, M.; Czapla-Myers, J.; Holzwarth, S.; Khalsa, S. J.; Maclellan, C.; Malthus, T.; Nightingale, J.; hide

    2016-01-01

    Calibration and validation are fundamental for obtaining quantitative information from Earth Observation (EO) sensor data. Recognising this and the impending launch of at least five sensors in the next five years, the International Spaceborne Imaging Spectroscopy Technical Committee instigated a calibration and validation initiative. A workshop was conducted recently as part of this initiative with the objective of establishing a good practice framework for radiometric and spectral calibration and validation in support of spaceborne imaging spectroscopy missions. This paper presents the outcomes and recommendations for future work arising from the workshop.

  17. Radiometric analysis performed by the Environment Monitoring Service from IPEN (Institute of Energy and Nuclear Research), Brazil, between 1988 and 1991

    International Nuclear Information System (INIS)

    Venturini, L.; Nisti, M.B.; Pecequilo, B.R.S.

    1993-03-01

    This report presents the radiometric analyses made by the Environmental Monitoring Service from the Institute of Energy and Nuclear Research (IPEN), Brazil, in the period 1988-1991. The experimental procedures, the products analysed and their respective quantities are described. (F.E.). 11 refs, 3 tabs

  18. Calibration-on-the-spot”: How to calibrate an EMCCD camera from its images

    DEFF Research Database (Denmark)

    Mortensen, Kim; Flyvbjerg, Henrik

    2016-01-01

    In order to count photons with a camera, the camera must be calibrated. Photon counting is necessary, e.g., to determine the precision of localization-based super-resolution microscopy. Here we present a protocol that calibrates an EMCCD camera from information contained in isolated, diffraction-......-limited spots in any image taken by the camera, thus making dedicated calibration procedures redundant by enabling calibration post festum, from images filed without calibration information....

  19. Photometric Calibration and Image Stitching for a Large Field of View Multi-Camera System

    Directory of Open Access Journals (Sweden)

    Yu Lu

    2016-04-01

    Full Text Available A new compact large field of view (FOV multi-camera system is introduced. The camera is based on seven tiny complementary metal-oxide-semiconductor sensor modules covering over 160° × 160° FOV. Although image stitching has been studied extensively, sensor and lens differences have not been considered in previous multi-camera devices. In this study, we have calibrated the photometric characteristics of the multi-camera device. Lenses were not mounted on the sensor in the process of radiometric response calibration to eliminate the influence of the focusing effect of uniform light from an integrating sphere. Linearity range of the radiometric response, non-linearity response characteristics, sensitivity, and dark current of the camera response function are presented. The R, G, and B channels have different responses for the same illuminance. Vignetting artifact patterns have been tested. The actual luminance of the object is retrieved by sensor calibration results, and is used to blend images to make panoramas reflect the objective luminance more objectively. This compensates for the limitation of stitching images that are more realistic only through the smoothing method. The dynamic range limitation of can be resolved by using multiple cameras that cover a large field of view instead of a single image sensor with a wide-angle lens. The dynamic range is expanded by 48-fold in this system. We can obtain seven images in one shot with this multi-camera system, at 13 frames per second.

  20. Calibration of nuclear medicine gamma counters

    International Nuclear Information System (INIS)

    Orlic, M.; Spasic-Jokic, V.; Jovanovic, M.; Vranjes, S. . E-mail address of corresponding author: morlic@vin.bg.ac.yu; Orlic, M.)

    2005-01-01

    In this paper the practical problem of nuclear medicine gamma counters calibration has been solved by using dose calibrators CRC-15R with standard error ±5%. The samples from technetium generators have been measured both by dose calibrators CRC-15R and gamma counter ICN Gamma 3.33 taking into account decay correction. Only the linear part of the curve has practical meaning. The advantage of this procedure satisfies the requirements from international standards: the calibration of sources used for medical exposure be traceable to a standard dosimetry laboratory and radiopharmaceuticals for nuclear medicine procedures be calibrated in terms of activity of the radiopharmaceutical to be administered. (author)

  1. Radiometric measurement techniques in metallurgy and foundry technology

    International Nuclear Information System (INIS)

    1990-01-01

    The contributions contain informations concerning the present state and development of radiometric measurement techniques in metallurgy and foundry technology as well as their application to the solution of various problems. The development of isotope techniques is briefly described. Major applications of radiometric equipment in industrial measurement are presented together with the use of isotopes to monitor processes of industrial production. This is followed by a short description of numerous laboratory-scale applications. Another contribution deals with fundamental problems and methods of moisture measurement by neutrons. A complex moisture/density measurement device the practical applicability of which has been tested is described here. Possibilities for clay determination in used-up moulding materials are discussed in a further contribution. The clay content can be determined by real-time radiometric density measurement so that the necessary moisture or addition of fresh sand can be controlled. (orig.) With 20 figs., 9 tabs., 178 refs [de

  2. Calibrating the neutron moisture meter: Precision and economy

    International Nuclear Information System (INIS)

    Akhter, J.; Waheed, R.A.; Hignett, C.T.; Greacen, E.L.

    2000-01-01

    Established laboratory and field calibration procedures for the neutron moisture meter are demonstrated on a uniform soil and alternative, low cost procedures on a duplex, less uniform soil. The effect of field variability on the calibration methodology is discussed with the aim of optimising calibration reliability at minimal cost. The difference between calibration for a soil material, or for a field (a range of soil materials) is considered. In particular, calibration for the estimation of water content change is shown to be a different problem from calibration for the estimation of water content in a variable field. Techniques aimed at detecting field variability problems during calibration are suggested, and methods for optimising the results for the intended use of the instrument are outlined. Pairing of calibration tubes, alternative methods of analysis of calibration data, and use of other information from the field to measure its variability, can improve the precision of calibration procedures to the point where minimal calibration effort, with careful analysis, can provide reliable results. (author)

  3. A novel single-step procedure for the calibration of the mounting parameters of a multi-camera terrestrial mobile mapping system

    Science.gov (United States)

    Habib, A.; Kersting, P.; Bang, K.; Rau, J.

    2011-12-01

    Mobile Mapping Systems (MMS) can be defined as moving platforms which integrates a set of imaging sensors and a position and orientation system (POS) for the collection of geo-spatial information. In order to fully explore the potential accuracy of such systems and guarantee accurate multi-sensor integration, a careful system calibration must be carried out. System calibration involves individual sensor calibration as well as the estimation of the inter-sensor geometric relationship. This paper tackles a specific component of the system calibration process of a multi-camera MMS - the estimation of the relative orientation parameters among the cameras, i.e., the inter-camera geometric relationship (lever-arm offsets and boresight angles among the cameras). For that purpose, a novel single step procedure, which is easy to implement and not computationally intensive, will be introduced. The proposed method is implemented in such a way that it can also be used for the estimation of the mounting parameters among the cameras and the IMU body frame, in case of directly georeferenced systems. The performance of the proposed method is evaluated through experimental results using simulated data. A comparative analysis between the proposed single-step and the two-step, which makes use of the traditional bundle adjustment procedure, is demonstrated.

  4. Vicarious Calibration of sUAS Microbolometer Temperature Imagery for Estimation of Radiometric Land Surface Temperature

    Directory of Open Access Journals (Sweden)

    Alfonso Torres-Rua

    2017-06-01

    /um for all sUAS flights. Differences in estimated temperatures between original thermal image and the vicarious calibration procedure reported here were estimated from −5 °C to 10 °C for early morning, and from 0 to 20 °C for Landsat overpass and mid-afternoon times.

  5. SPOTS Calibration Example

    Directory of Open Access Journals (Sweden)

    Patterson E.

    2010-06-01

    Full Text Available The results are presented using the procedure outlined by the Standardisation Project for Optical Techniques of Strain measurement to calibrate a digital image correlation system. The process involves comparing the experimental data obtained with the optical measurement system to the theoretical values for a specially designed specimen. The standard states the criteria which must be met in order to achieve successful calibration, in addition to quantifying the measurement uncertainty in the system. The system was evaluated at three different displacement load levels, generating strain ranges from 289 µstrain to 2110 µstrain. At the 289 µstrain range, the calibration uncertainty was found to be 14.1 µstrain, and at the 2110 µstrain range it was found to be 28.9 µstrain. This calibration procedure was performed without painting a speckle pattern on the surface of the metal. Instead, the specimen surface was prepared using different grades of grit paper to produce the desired texture.

  6. CALIBRATION PROCEDURES IN MID FORMAT CAMERA SETUPS

    Directory of Open Access Journals (Sweden)

    F. Pivnicka

    2012-07-01

    Full Text Available A growing number of mid-format cameras are used for aerial surveying projects. To achieve a reliable and geometrically precise result also in the photogrammetric workflow, awareness on the sensitive parts is important. The use of direct referencing systems (GPS/IMU, the mounting on a stabilizing camera platform and the specific values of the mid format camera make a professional setup with various calibration and misalignment operations necessary. An important part is to have a proper camera calibration. Using aerial images over a well designed test field with 3D structures and/or different flight altitudes enable the determination of calibration values in Bingo software. It will be demonstrated how such a calibration can be performed. The direct referencing device must be mounted in a solid and reliable way to the camera. Beside the mechanical work especially in mounting the camera beside the IMU, 2 lever arms have to be measured in mm accuracy. Important are the lever arms from the GPS Antenna to the IMU's calibrated centre and also the lever arm from the IMU centre to the Camera projection centre. In fact, the measurement with a total station is not a difficult task but the definition of the right centres and the need for using rotation matrices can cause serious accuracy problems. The benefit of small and medium format cameras is that also smaller aircrafts can be used. Like that, a gyro bases stabilized platform is recommended. This causes, that the IMU must be mounted beside the camera on the stabilizer. The advantage is, that the IMU can be used to control the platform, the problematic thing is, that the IMU to GPS antenna lever arm is floating. In fact we have to deal with an additional data stream, the values of the movement of the stabiliser to correct the floating lever arm distances. If the post-processing of the GPS-IMU data by taking the floating levers into account, delivers an expected result, the lever arms between IMU and

  7. Calibration of SeaWiFS after two years on orbit

    Science.gov (United States)

    Barnes, Robert A.; McClain, Charles R.

    1999-12-01

    The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) was launched on 1 August 1997, and the first Earth images were taken on 4 September 1997. Regular, daily measurements of the sun, via the onboard diffuser, started on 9 September 1997 and regular, monthly measurements of the moon on November 14, 1997. These lunar measurements, as first reported at EUROPTO'98, provide a highly sensitive method for determining the change in the radiometric sensitivity of SeaWiFS. The prelaunch radiometric calibration used by SeaWiFS was performed in the Spring of 1997 at the spacecraft manufacturer's facility. The calibration measurements were made by a team from the National Institute of Standards and Technology (NIST) and the SeaWiFS Project. The uncertainties in this calibration range from 2% to 3% for the eight SeaWiFS bands. In addition, a set of outdoor measurements of the sun were made at the instrument manufacturer's facility in November 1993, just before the delivery of SeaWiFS to the spacecraft manufacturer. These solar measurements, using the instrument's diffuser, were combined with a separate set of solar radiometer measurements to determine the transmittance of the atmosphere. At the start of on-orbit measurements by SeaWiFS, solar measurements were made again by the instrument. These two sets of measurements make up the transfer-to-orbit experiment. From the ground measurements, the outputs of the SeaWiFS bands on orbit were predicted. For each band, the output from the initial on-orbit measurements agree with the predicted values by 21/2% or less. The uncertainties for the transfer-to-orbit experiment are estimated to be approximately 3% to 4%. From 14 November 1997 to 29 June 1999, SeaWiFS has made 20 measurements of the moon. The analysis of lunar measurements presented here has minor modifications to that presented at EUROPTO'98. The trend lines from the current analysis have been extrapolated back from 14 November 1997 to 4 September 1997 to describe the changes

  8. A method to calibrate a solar pyranometer for measuring reference diffuse irradiance

    Energy Technology Data Exchange (ETDEWEB)

    Reda, I.; Stoffel, T.; Myers, D. [National Renewable Energy Laboratory, Golden, CO (United States)

    2003-02-01

    Accurate pyranometer calibrations, traceable to internationally recognized standards, are critical for solar irradiance measurements. One calibration method is the component summation, where the pyranometers are calibrated outdoors under clear sky conditions, and the reference global solar irradiance is calculated as the sum of two reference components, the diffuse and subtended beam solar irradiances. The beam component is measured with pyrheliometers traceable to the World Radiometric Reference, while there is no internationally recognized reference for the diffuse component. In the absence of such a reference, we present a method to consistently calibrate pyranometers for measuring the diffuse component with an estimated uncertainty of {+-} (3% of reading +1 W/m{sup 2}). The method is based on using a modified shade/unshade method, and pyranometers with less than 1 W/m{sup 2} thermal offset errors. We evaluated the consistency of our method by calibrating three pyranometers four times. Calibration results show that the responsivity change is within {+-} 0.52% for the three pyranometers. We also evaluated the effect of calibrating pyranometers unshaded, then using them shaded to measure diffuse irradiance. We calibrated three unshaded pyranometers using the component summation method. Their outdoor measurements of clear sky diffuse irradiance, from sunrise to sundown, showed that the three calibrated pyranometers can be used to measure the diffuse irradiance to within {+-} 1.4 W/m{sup 2} variation from the reference irradiance. (author)

  9. Complex optimization of radiometric control and measurement systems

    International Nuclear Information System (INIS)

    Onishchenko, A.M.

    1995-01-01

    Fundamentals of a new approach to increase in the accuracy of radiometric systems of control and measurements are presented in succession. Block diagram of the new concept of radiometric system optimization is provided. The approach involving radical increase in accuracy and envisages ascertaining of controlled parameter by the totality of two intelligence signals closely correlated with each other. The new concept makes use of system analysis as a unified one-piece object, permitting euristic synthesis of the system. 4 refs., 3 figs

  10. Linear Calibration – Is It so Simple?

    International Nuclear Information System (INIS)

    Arsova, Diana; Babanova, Sofia; Mandjukov, Petko

    2009-01-01

    Calibration procedure is an important part of instrumental analysis. Usually it is not the major uncertainty source in whole analytical procedure. However, improper calibration might cause a significant bias of the analytical results from the real (certified) value. Standard Gaussian linear regression is the most frequently used mathematical approach for estimation of calibration function parameters. In the present article are discussed some not quite popular, but highly recommended in certain cases methods for parameter estimation, such as: weighted regression, orthogonal regression, robust regression, bracketing calibration etc. Some useful approximations are also presented. Special attention is paid to the statistical criteria which to be used for selection of proper calibration model. Standard UV-VIS spectrometric procedure for determination of phosphates in water was used as a practical example. Several different approaches for estimation of the contribution of calibration to the general un-certainty of the analytical result are presented and compared

  11. Airborne gamma-ray spectrometer and magnetometer survey: Crescent Quadrangle, Burns Quadrangle, Canyon City Quadrangle, Bend Quadrangle, Salem Quadrangle (Oregon). Final report

    International Nuclear Information System (INIS)

    1981-01-01

    An airborne combining radiometric and magnetic survey was performed for the Department of Energy over the area covered by the Burns, Crescent, Canyon City, Bend, and Salem, Washington 1:250,000 National Topographic Map Series, 1 0 x 2 0 quadrangle maps. The survey was a part of DOE's National Aerial Radiometric Reconnaissance program, which is in turn a part of the National Uranium Resource Evaluation program. Data were collected by a helicopter equipped with a gamma-ray spectrometer having a large crystal volume, and a high sensitivity proton precession magnetometer. The radiometric system was calibrated at the Walker Field Calibration pads and the Lake Mead Dynamic Test range. Data quality was ensured throughout the survey by daily test flights and equipment checks. Radiometric data were corrected for live time, aircraft and equipment background, cosmic background, atmospheric radon, Compton scatter, and altitude dependence. The corrected data were statistically evaluated, plotted, and contoured to produce anomaly maps based on the radiometric response of individual geological units. These maps were interpreted and an anomaly interpretation map produced. Volume I contains a description of the systems used in the survey, a discussion of the calibration of the systems, the data processing procedures, the data display format, the interpretation rationale, and the interpretation methodology. A separate Volume II for each quadrangle contains the data displays and the interpretation results

  12. Airborne gamma-ray spectrometer and magnetometer survey. Volume I. Final report

    International Nuclear Information System (INIS)

    An airborne combined radiometric and magnetic survey was performed for the Department of Energy (DOE) over the area covered by the Mariposa, California and Nevada; Fresno, California; and Bakersfield, Caifornia 1:250,000 National Topographic Map Series (NTMS) 1 0 x 2 0 quadrangle maps. The survey was a part of DOE's National Aerial Radiometric Reconnaissance (ARR) program, which in turn is a part of the National Uranium Resource Evaluation (NURE) program. Data were collected by a helicopter equipped with a gamma-ray spectrometer having a large crystal volume, and a high sensitivity proton precession magnetometer. The radiometric system was calibrated at the Walker Field Calibration pads and the Lake Mead Dynamic Test range. Data quality was ensured throughout the survey by daily test flights and equipment checks. Radiometric data were corrected for live time, aircraft and equipment background, cosmic background, atmospheric radon, Compton scatter, and altitude dependence. The corrected data were statistically evaluated, plotted, and contoured to produce anomaly maps based on the radiometric response of individual geological units. These maps were interpreted and an anomaly interpretation map produced. Volume I contains a description of the systems used in the survey, a discussion of the calibration of the systems, the data processing procedures, the data display format, the interpretation rationale, and the interpretation methodology. A separate Volume II for each quadrangle contains the data displays and the interpretation results

  13. Mathematical Model and Calibration Procedure of a PSD Sensor Used in Local Positioning Systems.

    Science.gov (United States)

    Rodríguez-Navarro, David; Lázaro-Galilea, José Luis; Bravo-Muñoz, Ignacio; Gardel-Vicente, Alfredo; Domingo-Perez, Francisco; Tsirigotis, Georgios

    2016-09-15

    Here, we propose a mathematical model and a calibration procedure for a PSD (position sensitive device) sensor equipped with an optical system, to enable accurate measurement of the angle of arrival of one or more beams of light emitted by infrared (IR) transmitters located at distances of between 4 and 6 m. To achieve this objective, it was necessary to characterize the intrinsic parameters that model the system and obtain their values. This first approach was based on a pin-hole model, to which system nonlinearities were added, and this was used to model the points obtained with the nA currents provided by the PSD. In addition, we analyzed the main sources of error, including PSD sensor signal noise, gain factor imbalances and PSD sensor distortion. The results indicated that the proposed model and method provided satisfactory calibration and yielded precise parameter values, enabling accurate measurement of the angle of arrival with a low degree of error, as evidenced by the experimental results.

  14. Intercomparison and calibration of dose calibrators used in nuclear medicine facilities

    CERN Document Server

    Costa, A M D

    2003-01-01

    The aim of this work was to establish a working standard for intercomparison and calibration of dose calibrators used in most of nuclear medicine facilities for the determination of the activity of radionuclides administered to patients in specific examinations or therapeutic procedures. A commercial dose calibrator, a set of standard radioactive sources, and syringes, vials and ampoules with radionuclide solutions used in nuclear medicine were utilized in this work. The commercial dose calibrator was calibrated for radionuclide solutions used in nuclear medicine. Simple instrument tests, such as linearity response and variation response with the source volume at a constant source activity concentration were performed. This instrument may be used as a reference system for intercomparison and calibration of other activity meters, as a method of quality control of dose calibrators utilized in nuclear medicine facilities.

  15. A Novel Non-Intrusive Method to Resolve the Thermal-Dome-Effect of Pyranometers: Radiometric Calibration and Implications

    Science.gov (United States)

    Ji, Qiang; Tsay, Si-Chee; Lau, K. M.; Hansell, R. A.; Butler, J. J.; Cooper, J. W.

    2011-01-01

    Traditionally the calibration equation for pyranometers assumes that the measured solar irradiance is solely proportional to the thermopile's output voltage; therefore only a single calibration factor is derived. This causes additional measurement uncertainties because it does not capture sufficient information to correctly account for a pyranometer's thermal effect. In our updated calibration equation, temperatures from the pyranometer's dome and case are incorporated to describe the instrument's thermal behavior, and a new set of calibration constants are determined, thereby reducing measurement uncertainties. In this paper, we demonstrate why a pyranometer's uncertainty using the traditional calibration equation is always larger than a-few-percent, but with the new approach can become much less than 1% after the thermal issue is resolved. The highlighted calibration results are based on NIST-traceable light sources under controlled laboratory conditions. The significance of the new approach lends itself to not only avoiding the uncertainty caused by a pyranometer's thermal effect but also the opportunity to better isolate and characterize other instrumental artifacts, such as angular response and non-linearity of the thermopile, to further reduce additional uncertainties. We also discuss some of the implications, including an example of how the thermal issue can potentially impact climate studies by evaluating aerosol's direct-radiative effect using field measurements with and without considering the pyranometer's thermal effect. The results of radiative transfer model simulation show that a pyranometer's thermal effect on solar irradiance measurements at the surface can be translated into a significant alteration of the calculated distribution of solar energy inside the column atmosphere.

  16. Map of natural gamma radiation in Spain: radiometric characterization of different types of surfaces

    International Nuclear Information System (INIS)

    Suarez Mahou, E.; Fernandez Amigot, J.A.; Botas Medina, J.

    1997-01-01

    The gamma radioactivity flowing from ground and rocks is due to the presence in these of uranium, thorium and potassium-40. The method of radiometric characterization depends on the purpose of the undertaking. Radiometric characterization can be realized on big surfaces (tens or hundreds of square kilometres studied on a national scale), medium size surfaces (50 to 1000 square kilometres, for example, in epidemiological or biological studies in areas with a determined radiometric background) small surfaces of less than 50 square kilometres (industrial sites, pre-operational studies, etc.). This article considers aspects of radiometric characterization on surfaces of interest and describes the contribution of the MARNA (Natural Provisional Radiation Map of Spain) Project selection and radiometric characterization

  17. Exposure-rate calibration using large-area calibration pads

    International Nuclear Information System (INIS)

    Novak, E.F.

    1988-09-01

    The US Department of Energy (DOE) Office of Remedial Action and Waste Technology established the Technical Measurements Center (TMC) at the DOE Grand Junction Projects Office (GJPO) in Grand Junction, Colorado, to standardize, calibrate, and compare measurements made in support of DOE remedial action programs. A set of large-area, radioelement-enriched concrete pads was constructed by the DOE in 1978 at the Walker Field Airport in Grand Junction for use as calibration standards for airborne gamma-ray spectrometer systems. The use of these pads was investigated by the TMC as potential calibration standards for portable scintillometers employed in measuring gamma-ray exposure rates at Uranium Mill Tailings Remedial Action (UMTRA) project sites. Data acquired on the pads using a pressurized ionization chamber (PIC) and three scintillometers are presented as an illustration of an instrumental calibration. Conclusions and recommended calibration procedures are discussed, based on the results of these data

  18. Another look at volume self-calibration: calibration and self-calibration within a pinhole model of Scheimpflug cameras

    International Nuclear Information System (INIS)

    Cornic, Philippe; Le Besnerais, Guy; Champagnat, Frédéric; Illoul, Cédric; Cheminet, Adam; Le Sant, Yves; Leclaire, Benjamin

    2016-01-01

    We address calibration and self-calibration of tomographic PIV experiments within a pinhole model of cameras. A complete and explicit pinhole model of a camera equipped with a 2-tilt angles Scheimpflug adapter is presented. It is then used in a calibration procedure based on a freely moving calibration plate. While the resulting calibrations are accurate enough for Tomo-PIV, we confirm, through a simple experiment, that they are not stable in time, and illustrate how the pinhole framework can be used to provide a quantitative evaluation of geometrical drifts in the setup. We propose an original self-calibration method based on global optimization of the extrinsic parameters of the pinhole model. These methods are successfully applied to the tomographic PIV of an air jet experiment. An unexpected by-product of our work is to show that volume self-calibration induces a change in the world frame coordinates. Provided the calibration drift is small, as generally observed in PIV, the bias on the estimated velocity field is negligible but the absolute location cannot be accurately recovered using standard calibration data. (paper)

  19. Radiometric study of creep in ingot rolling

    International Nuclear Information System (INIS)

    Kubicek, P.; Zamyslovsky, Z.; Uherek, J.

    The radiometric study of creep during ingot rolling performed in the rolling mill of the Vitkovice Iron and Steel Works and the first results are described. Selected sites in 3 to 8 ton ingots were labelled with 2 to 3.7x10 5 Bq of 60 Co and after rolling into blocks, the transposition of the labelled sites of the ingots was investigated. The results indicate creep during rolling, local extension in certain sites under study and help to determine the inevitable bottom crop incurred in the forming. Finally, the requirements put on the radiometric apparatus for the next stages of technological research are presented. (author)

  20. Lidar to lidar calibration phase 2

    DEFF Research Database (Denmark)

    Yordanova, Ginka; Courtney, Michael

    This report presents the results from phase 2 of a lidar to lidar (L2L) calibration procedure. Phase two of the project included two measurement campaigns conducted at given sites. The purpose was to find out if the lidar-to-lidar calibration procedure can be conducted with similar results...

  1. 40 CFR 90.424 - Dilute sampling procedures-CVS calibration.

    Science.gov (United States)

    2010-07-01

    ... calibration. 90.424 Section 90.424 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... “true” value) for the CVS calibration. (Note: In no case should an upstream screen or other restriction... Parameter Symbol Units Sensor-readout tolerances Barometric pressure (corrected) PB kPa ±.340 kPa. Ambient...

  2. Field radiometric methods of prospecting and exploration for uranium ores

    International Nuclear Information System (INIS)

    Gorbushina, L.V.; Savenko, E.I.; Serdyukova, A.S.

    1978-01-01

    The textbook includes two main chapters which describe gamma- and emanation field radiometric methods. The textbook is intended for geology and geophysics students having training practice in field radiometric methods and is additional to the course of lectures. The textbook can be used in the''Radiometry'' course which is studied in appropriate geological and technical colleges

  3. Mechanics of log calibration

    International Nuclear Information System (INIS)

    Waller, W.C.; Cram, M.E.; Hall, J.E.

    1975-01-01

    For any measurement to have meaning, it must be related to generally accepted standard units by a valid and specified system of comparison. To calibrate well-logging tools, sensing systems are designed which produce consistent and repeatable indications over the range for which the tool was intended. The basics of calibration theory, procedures, and calibration record presentations are reviewed. Calibrations for induction, electrical, radioactivity, and sonic logging tools will be discussed. The authors' intent is to provide an understanding of the sources of errors, of the way errors are minimized in the calibration process, and of the significance of changes in recorded calibration data

  4. Itinerant radiometric laboratory (IRL-76)

    International Nuclear Information System (INIS)

    Dolgirev, E.I.; Domaratskij, V.P.; Kostikov, Yu.I.

    1978-01-01

    A mobile radiometric laboratory for routine radiation monitoring of the environment, personnel, and population is described. As compared to the previous models, this one incorporates a number of new features and is more informative and versatile. The design and main technical and operating characteristics of the laboratory are detailed

  5. The use of radiometric ore sorting on South African gold mines

    International Nuclear Information System (INIS)

    Boehme, R.C.; Freer, J.S.

    1982-01-01

    This paper refers to the radiometric sorting tests reported during the 7th CMMI Congress, and then describes the photometric and radiometric sorter installations in operation and under construction in South Africa at present. As radiometric sorting of gold ores uses the radiation from the uranium content as a tracer, it is essential that the sortability of the ore should be reliably determined before sorting is adopted. The method of obtaining the important ore characteristics is described, with examples. The possible increase in gold production from a hypothetical plant as a result of sorting is shown

  6. Radiometric determination of monoethanolamine with 65ZnSo4

    International Nuclear Information System (INIS)

    Varadan, R.; Sriman Narayanan, S.; Rao, V.R.S.

    1984-01-01

    Determination of milligram amounts of monoethanolamine (MEA) with zinc(II) by radiometric titration is described. When MEA is added to a zinc(II) solution containing sulphate ions at 25 degC, a white solid complex is formed. The formation of this complex is employed for the radiometric determination of MEA with 65 Zn. The amount of MEA is directly proportional to the activity of the complex formed. The method is simple, rapid and accurate. (author)

  7. Test of an albedo neutron dosimetry system: TLD calibration and readout procedure, neutron calibration, dosimetry properties, routine application

    International Nuclear Information System (INIS)

    Piesch, E.; Burgkhardt, B.

    1988-03-01

    The two-component albedo dosemeter in use consists of an universal boron-loaded plastic encapsulation, the beta and albedo neutron windows of which are adopted to the corresponding TLD system of the manufacturers Alnor, Harshaw, Panasonic and Vinten. Beside the TLD detectors the capsule may contain also track etch detectors. Within a BMU project the system was investigated by four governmental measurement services in the FRG with respect to its qualification for personnel monitoring with emphasis in the readout and calibration procedures for the TLD system, the evaluation technique for the estimation of the photon and neutron dose equivalent in routine monitoring and the calibration of the personnel dosemeter in stray neutron fields. The test has shown the readiness of the system to act in the application areas of nuclear power reactors and linacs behind heavy shieldings, in the fuel element cycle, use of fissile materials, criticality, use of radionuclide sources, high energy particle accelerators. The uncertainty due to energy dependence was found to be within a factor of 2 for a single application area. In the case of irradiations from the front half space the dose equivalent H'(10) is indicated sufficiently independent of the direction of the radiation incidence. After completion of the test the albedo dosemeter became the official neutron personnel dosemeter in the FRG. It allows the separate estimation of the dose equivalent of hard beta radiation, photon radiation and neutrons. (orig./HP) [de

  8. Ash content of lignites - radiometric analysis

    International Nuclear Information System (INIS)

    Leonhardt, J.; Thuemmel, H.W.

    1986-01-01

    The quality of lignites is governed by the ash content varying in dependence upon the geologic conditions. Setup and function of the radiometric devices being used for ash content analysis in the GDR are briefly described

  9. Nitrous oxide emissions from cropland: a procedure for calibrating the DayCent biogeochemical model using inverse modelling

    Science.gov (United States)

    Rafique, Rashad; Fienen, Michael N.; Parkin, Timothy B.; Anex, Robert P.

    2013-01-01

    DayCent is a biogeochemical model of intermediate complexity widely used to simulate greenhouse gases (GHG), soil organic carbon and nutrients in crop, grassland, forest and savannah ecosystems. Although this model has been applied to a wide range of ecosystems, it is still typically parameterized through a traditional “trial and error” approach and has not been calibrated using statistical inverse modelling (i.e. algorithmic parameter estimation). The aim of this study is to establish and demonstrate a procedure for calibration of DayCent to improve estimation of GHG emissions. We coupled DayCent with the parameter estimation (PEST) software for inverse modelling. The PEST software can be used for calibration through regularized inversion as well as model sensitivity and uncertainty analysis. The DayCent model was analysed and calibrated using N2O flux data collected over 2 years at the Iowa State University Agronomy and Agricultural Engineering Research Farms, Boone, IA. Crop year 2003 data were used for model calibration and 2004 data were used for validation. The optimization of DayCent model parameters using PEST significantly reduced model residuals relative to the default DayCent parameter values. Parameter estimation improved the model performance by reducing the sum of weighted squared residual difference between measured and modelled outputs by up to 67 %. For the calibration period, simulation with the default model parameter values underestimated mean daily N2O flux by 98 %. After parameter estimation, the model underestimated the mean daily fluxes by 35 %. During the validation period, the calibrated model reduced sum of weighted squared residuals by 20 % relative to the default simulation. Sensitivity analysis performed provides important insights into the model structure providing guidance for model improvement.

  10. A study of elemental migration from poly(ethylene terephthalate) of food packagings to simulated solutions by radiometric method

    International Nuclear Information System (INIS)

    Soares, Eufemia Paez; Saki, Mitiko; Silva, Leonardo G.A.

    2007-01-01

    Brazilian plastic production for food packagings, in recent years, has grown in the same proportion as food consumption. Considering that the plastic manufacturing involves catalytic processes and the use of additives, when the foods are in direct contact with these materials, the components present in plastics may migrate to the food. The Brazilian Health Surveillance Agency (ANVISA) has established boundary-values of migrants as well as procedures to evaluate migration of elements and substances from plastic packaging to food. In this study elemental composition of poly (ethylene terephthalate) - PET - packaging and results of elemental migration were obtained. Instrumental Neutron Activation Analysis (INAA) was used to determine elemental concentrations in PET packagings and the radiometric method was applied for elemental migration determination. This radiometric method consisted of irradiating the PET samples with neutrons, followed by migration exposition and radioactivity measurement in food-simulated solution. Experimental conditions used for migration were 10 days exposure period at 40 deg C. Migration was evaluated for soft drink, juice and water PET packaging. The analytical results indicated that PET packagings contain Co and Sb and those elements are transferred to the simulated solutions. However, these migration results were lower than the maximum tolerance values established by ANVISA. The migration detection limits also indicated high sensitivity of the radiometric method. (author)

  11. Reconstructing the calibrated strain signal in the Advanced LIGO detectors

    Science.gov (United States)

    Viets, A. D.; Wade, M.; Urban, A. L.; Kandhasamy, S.; Betzwieser, J.; Brown, Duncan A.; Burguet-Castell, J.; Cahillane, C.; Goetz, E.; Izumi, K.; Karki, S.; Kissel, J. S.; Mendell, G.; Savage, R. L.; Siemens, X.; Tuyenbayev, D.; Weinstein, A. J.

    2018-05-01

    Advanced LIGO’s raw detector output needs to be calibrated to compute dimensionless strain h(t) . Calibrated strain data is produced in the time domain using both a low-latency, online procedure and a high-latency, offline procedure. The low-latency h(t) data stream is produced in two stages, the first of which is performed on the same computers that operate the detector’s feedback control system. This stage, referred to as the front-end calibration, uses infinite impulse response (IIR) filtering and performs all operations at a 16 384 Hz digital sampling rate. Due to several limitations, this procedure currently introduces certain systematic errors in the calibrated strain data, motivating the second stage of the low-latency procedure, known as the low-latency gstlal calibration pipeline. The gstlal calibration pipeline uses finite impulse response (FIR) filtering to apply corrections to the output of the front-end calibration. It applies time-dependent correction factors to the sensing and actuation components of the calibrated strain to reduce systematic errors. The gstlal calibration pipeline is also used in high latency to recalibrate the data, which is necessary due mainly to online dropouts in the calibrated data and identified improvements to the calibration models or filters.

  12. Permanently calibrated interpolating time counter

    International Nuclear Information System (INIS)

    Jachna, Z; Szplet, R; Kwiatkowski, P; Różyc, K

    2015-01-01

    We propose a new architecture of an integrated time interval counter that provides its permanent calibration in the background. Time interval measurement and the calibration procedure are based on the use of a two-stage interpolation method and parallel processing of measurement and calibration data. The parallel processing is achieved by a doubling of two-stage interpolators in measurement channels of the counter, and by an appropriate extension of control logic. Such modification allows the updating of transfer characteristics of interpolators without the need to break a theoretically infinite measurement session. We describe the principle of permanent calibration, its implementation and influence on the quality of the counter. The precision of the presented counter is kept at a constant level (below 20 ps) despite significant changes in the ambient temperature (from −10 to 60 °C), which can cause a sevenfold decrease in the precision of the counter with a traditional calibration procedure. (paper)

  13. Line fiducial material and thickness considerations for ultrasound calibration

    Science.gov (United States)

    Ameri, Golafsoun; McLeod, A. J.; Baxter, John S. H.; Chen, Elvis C. S.; Peters, Terry M.

    2015-03-01

    Ultrasound calibration is a necessary procedure in many image-guided interventions, relating the position of tools and anatomical structures in the ultrasound image to a common coordinate system. This is a necessary component of augmented reality environments in image-guided interventions as it allows for a 3D visualization where other surgical tools outside the imaging plane can be found. Accuracy of ultrasound calibration fundamentally affects the total accuracy of this interventional guidance system. Many ultrasound calibration procedures have been proposed based on a variety of phantom materials and geometries. These differences lead to differences in representation of the phantom on the ultrasound image which subsequently affect the ability to accurately and automatically segment the phantom. For example, taut wires are commonly used as line fiducials in ultrasound calibration. However, at large depths or oblique angles, the fiducials appear blurred and smeared in ultrasound images making it hard to localize their cross-section with the ultrasound image plane. Intuitively, larger diameter phantoms with lower echogenicity are more accurately segmented in ultrasound images in comparison to highly reflective thin phantoms. In this work, an evaluation of a variety of calibration phantoms with different geometrical and material properties for the phantomless calibration procedure was performed. The phantoms used in this study include braided wire, plastic straws, and polyvinyl alcohol cryogel tubes with different diameters. Conventional B-mode and synthetic aperture images of the phantoms at different positions were obtained. The phantoms were automatically segmented from the ultrasound images using an ellipse fitting algorithm, the centroid of which is subsequently used as a fiducial for calibration. Calibration accuracy was evaluated for these procedures based on the leave-one-out target registration error. It was shown that larger diameter phantoms with lower

  14. Testing of X-ray radiometric enrichnment of polymetallic ores

    International Nuclear Information System (INIS)

    Eliseev, N.I.; Panova, N.I.; Kirbitova, N.V.; Shramm, E.O.; Efremov, Yu.G.

    1987-01-01

    Testing of X-ray radiometric method of sorting of polymetallic ores using the developed X-ray radiometric device was conducted. It was shown that introduction of preliminary concentration at the factory made the method of fragment separation to be the perspective one, enabling to elevate the factory production with respect to commercial ore and reduce the cost of ore processing. In the case of preliminary concentration, conducted at the mine, it is advisable to perform ore sorting in the flow formed to monolayer

  15. Archimedean Spiral Antenna Calibration Procedures to Increase the Downrange Resolution of a SFCW Radar

    Directory of Open Access Journals (Sweden)

    Ioan Nicolaescu

    2008-01-01

    Full Text Available This paper deals with the calibration procedures of an Archimedean spiral antenna used for a stepped frequency continuous wave radar (SFCW, which works from 400 MHz to 4845 MHz. Two procedures are investigated, one based on an error-term flow graph for the frequency signal and the second based on a reference metallic plate located at a certain distance from the ground in order to identify the phase dispersion given by the antenna. In the second case, the received signal is passed in time domain by applying an ifft, the multiple reflections are removed and the phase variation due to the time propagation is subtracted. After phase correction, the time domain response as well as the side lobes level is decreased. The antenna system made up of two Archimedean spirals is employed by SFCW radar that operates with a frequency step of 35 MHz.

  16. Novel Real-time Calibration and Alignment Procedure for LHCb Run II

    CERN Multimedia

    Prouve, Claire

    2016-01-01

    In order to achieve optimal detector performance the LHCb experiment has introduced a novel real-time detector alignment and calibration strategy for Run II of the LHC. For the alignment tasks, data is collected and processed at the beginning of each fill while the calibrations are performed for each run. This real time alignment and calibration allows the same constants being used in both the online and offline reconstruction, thus improving the correlation between triggered and offline selected events. Additionally the newly computed alignment and calibration constants can be instantly used in the trigger, making it more efficient. The online alignment and calibration of the RICH detectors also enable the use of hadronic particle identification in the trigger. The computing time constraints are met through the use of a new dedicated framework using the multi-core farm infrastructure for the LHCb trigger. An overview of all alignment and calibration tasks is presented and their performance is shown.

  17. Modeling response variation for radiometric calorimeters

    International Nuclear Information System (INIS)

    Mayer, R.L. II.

    1986-01-01

    Radiometric calorimeters are widely used in the DOE complex for accountability measurements of plutonium and tritium. Proper characterization of response variation for these instruments is, therefore, vital for accurate assessment of measurement control as well as for propagation of error calculations. This is not difficult for instruments used to measure items within a narrow range of power values; however, when a single instrument is used to measure items over a wide range of power values, improper estimates of uncertainty can result since traditional error models for radiometric calorimeters assume that uncertainty is not a function of sample power. This paper describes methods which can be used to accurately estimate random response variation for calorimeters used to measure items over a wide range of sample powers. The model is applicable to the two most common modes of calorimeter operation: heater replacement and servo control. 5 refs., 4 figs., 1 tab

  18. GEOMETRIC AND RADIOMETRIC EVALUATION OF RASAT IMAGES

    Directory of Open Access Journals (Sweden)

    A. Cam

    2016-06-01

    Full Text Available 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.

  19. Preliminary Evaluation of GAOFEN-3 Polarimetric and Radiometric Accuracy by Corner Reflectors in Inner Mongolia

    Science.gov (United States)

    Shi, L.; Ding, X.; Li, P.; Yang, J.; Zhao, L.; Yang, L.; Chang, Y.; Yan, L.

    2018-04-01

    On August 10, 2016, China launched its first C-band full polarimetric radar satellite, named Gaofen-3 (GF-3), for urban and agriculture monitoring, landslide detection, ocean applications, etc. According to the design specification, GF-3 is expected to work at -35 dB crosstalk and 0.5 dB channel imbalance, with less than 10 degree error. The absolute radiometric bias is expected to be less than 1.5 dB in a single scene and 2.0 dB when operating for a long time. To complete the calibration and evaluation, the Institute of Electronics, Chinese Academy Sciences (IECAS) built a test site at Inner Mongolia, and deployed active reflectors (ARs) and trihedral corner reflectors (CRs) to solve and evaluate the hardware distortion. To the best of the authors' knowledge, the product accuracy of GF-3 has not been comprehensively evaluated in any open publication. The remote sensing community urgently requires a detailed report about the product accuracy and stability, before any subsequent application. From June to August of 2017, IECAS begun its second round ground campaign and deployed 10 CRs to evaluate product distortions. In this paper, we exploit Inner Mongolia CRs to investigate polarimetric and radiometric accuracy of QPSI I Stripmap. Although some CRs found fall into AR side lobe, the rest CRs enable us to preliminarily evaluate the accuracy of some special imaging beams. In the experimental part, the image of July 6, 2017 was checked by 5 trihedral CRs and the integration estimation method demonstrated the crosstalk varying from -42.65 to -32.74 dB, and the channel imbalance varying from -0.21 to 0.47 with phase error from -2.4 to 0.2 degree. Comparing with the theoretical radar cross-section of 1.235 m trihedral CR, i.e. 35 dB, the radiometric error varies about 0.20 ± 0.29 dB in HH channel and 0.40 ± 0.20 dB in VV channel.

  20. X-ray radiometric separation of low-grade tin ores

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, N.I.; Neverov, A.D.; Konovalov, V.M.; Mironov, I.I.; Zakharov, S.N.

    1984-10-01

    The investigations on evaluation of X-ray radiometric separation of off-grade tin ores of one of the deposits are carried out. The experiments have been performed at loboratory and pilot-commerical plants. /sup 241/Am has been used as a radiation source. In the course of facility commercial the ore has been separated by means of a device comprising a separator and gate separatin device. The results of X-ray radiometric separation have shown its high productive efficiency. Concentrates with higher tin content at high extraction from ores are obtained.

  1. X-ray radiometric separation of low-grade tin ores

    International Nuclear Information System (INIS)

    Kotler, N.I.; Neverov, A.D.; Konovalov, V.M.; Mironov, I.I.; Zakharov, S.N.

    1984-01-01

    The investigations on evaluation of X-ray radiometric separation of off-grade tin ores of one of the deposits are carried out. The experiments have been performed at loboratory and pilot-commerical plants. 241 Am has been used as a radiation source. In the course of facility commercial the ore has been separated by means of a device comprising a separator and gate separatin device. The results of X-ray radiometric separation have shown its high productive efficiency. Concentrates with higher tin content at high extraction from ores are obtained

  2. In-Flight Calibration of GF-1/WFV Visible Channels Using Rayleigh Scattering

    Directory of Open Access Journals (Sweden)

    Xingfeng Chen

    2017-05-01

    Full Text Available China is planning to launch more and more optical remote-sensing satellites with high spatial resolution and multistep gains. Field calibration, the current operational method of satellite in-flight radiometric calibration, still does not have enough capacity to meet these demands. Gaofen-1 (GF-1, as the first satellite of the Chinese High-resolution Earth Observation System, has been specially arranged to obtain 22 images over clean ocean areas using the Wide Field Viewing camera. Following this, Rayleigh scattering calibration was carried out for the visible channels with these images after the appropriate data processing steps. To guarantee a high calibration precision, uncertainty was analyzed in advance taking into account ozone, aerosol optical depth (AOD, seawater salinity, chlorophyll concentration, wind speed and solar zenith angle. AOD and wind speed were found to be the biggest error sources, which were also closely coupled to the solar zenith angle. Therefore, the best sample data for Rayleigh scattering calibration were selected at the following solar zenith angle of 19–22° and wind speed of 5–13 m/s to reduce the reflection contributed by the water surface. The total Rayleigh scattering calibration uncertainties of visible bands are 2.44% (blue, 3.86% (green, and 4.63% (red respectively. Compared with the recent field calibration results, the errors are −1.69% (blue, 1.83% (green, and −0.79% (red. Therefore, the Rayleigh scattering calibration can become an operational in-flight calibration method for the high spatial resolution satellites.

  3. Inverting radiometric measurements with a neural network

    Science.gov (United States)

    Measure, Edward M.; Yee, Young P.; Balding, Jeff M.; Watkins, Wendell R.

    1992-02-01

    A neural network scheme for retrieving remotely sensed vertical temperature profiles was applied to observed ground based radiometer measurements. The neural network used microwave radiance measurements and surface measurements of temperature and pressure as inputs. Because the microwave radiometer is capable of measuring 4 oxygen channels at 5 different elevation angles (9, 15, 25, 40, and 90 degs), 20 microwave measurements are potentially available. Because these measurements have considerable redundancy, a neural network was experimented with, accepting as inputs microwave measurements taken at 53.88 GHz, 40 deg; 57.45 GHz, 40 deg; and 57.45, 90 deg. The primary test site was located at White Sands Missile Range (WSMR), NM. Results are compared with measurements made simultaneously with balloon borne radiosonde instruments and with radiometric temperature retrievals made using more conventional retrieval algorithms. The neural network was trained using a Widrow-Hoff delta rule procedure. Functions of date to include season dependence in the retrieval process and functions of time to include diurnal effects were used as inputs to the neural network.

  4. The Radiometric Bode's law and Extrasolar Planets

    National Research Council Canada - National Science Library

    Lazio, T. J; Farrell, W. M; Dietrick, Jill; Greenlees, Elizabeth; Hogan, Emily; Jones, Christopher; Hennig, L. A

    2004-01-01

    We predict the radio flux densities of the extrasolar planets in the current census, making use of an empirical relation the radiometric Bode's law determined from the five "magnetic" planets in the solar system...

  5. Electromagnetic Calorimeter Calibration with $\\pi^{0}$

    CERN Multimedia

    Puig Navarro, A

    2009-01-01

    Several methods can be used in order to achieve precise calibration of the LHCb Electromagnetic Calorimeter (ECAL) once reasonable cell equalization has been reached. At low transverse energy, the standard calibration procedure is an iterative method based on the fit of the $\\gamma\\gamma$ invariant mass distribution for each cell of the decay $\\pi^{0}\\to\\gamma\\gamma$ with resolved photons. A new technique for generating the combinatorial background of such decays directly from data has been developed. Knowledge of the background could allow an alternative calibration method based on a event by event fit of the same $\\gamma\\gamma$ invariant mass distribution where contributions from groups of cells are considered in a single fit. The background generation procedure and this possible new calibration method are presented in this poster, in addition to an overview of the LHCb Calorimetry system and ECAL calibration techniques.

  6. TES Level 1 Algorithms: Interferogram Processing, Geolocation, Radiometric, and Spectral Calibration

    Science.gov (United States)

    Worden, Helen; Beer, Reinhard; Bowman, Kevin W.; Fisher, Brendan; Luo, Mingzhao; Rider, David; Sarkissian, Edwin; Tremblay, Denis; Zong, Jia

    2006-01-01

    The Tropospheric Emission Spectrometer (TES) on the Earth Observing System (EOS) Aura satellite measures the infrared radiance emitted by the Earth's surface and atmosphere using Fourier transform spectrometry. The measured interferograms are converted into geolocated, calibrated radiance spectra by the L1 (Level 1) processing, and are the inputs to L2 (Level 2) retrievals of atmospheric parameters, such as vertical profiles of trace gas abundance. We describe the algorithmic components of TES Level 1 processing, giving examples of the intermediate results and diagnostics that are necessary for creating TES L1 products. An assessment of noise-equivalent spectral radiance levels and current systematic errors is provided. As an initial validation of our spectral radiances, TES data are compared to the Atmospheric Infrared Sounder (AIRS) (on EOS Aqua), after accounting for spectral resolution differences by applying the AIRS spectral response function to the TES spectra. For the TES L1 nadir data products currently available, the agreement with AIRS is 1 K or better.

  7. Mercury Continuous Emmission Monitor Calibration

    Energy Technology Data Exchange (ETDEWEB)

    John Schabron; Eric Kalberer; Ryan Boysen; William Schuster; Joseph Rovani

    2009-03-12

    Mercury continuous emissions monitoring systems (CEMs) are being implemented in over 800 coal-fired power plant stacks throughput the U.S. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor calibrators/generators. These devices are used to calibrate mercury CEMs at power plant sites. The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005 and vacated by a Federal appeals court in early 2008 required that calibration be performed with NIST-traceable standards. Despite the vacature, mercury emissions regulations in the future will require NIST traceable calibration standards, and EPA does not want to interrupt the effort towards developing NIST traceability protocols. The traceability procedures will be defined by EPA. An initial draft traceability protocol was issued by EPA in May 2007 for comment. In August 2007, EPA issued a conceptual interim traceability protocol for elemental mercury calibrators. The protocol is based on the actual analysis of the output of each calibration unit at several concentration levels ranging initially from about 2-40 {micro}g/m{sup 3} elemental mercury, and in the future down to 0.2 {micro}g/m{sup 3}, and this analysis will be directly traceable to analyses by NIST. The EPA traceability protocol document is divided into two separate sections. The first deals with the qualification of calibrator models by the vendors for use in mercury CEM calibration. The second describes the procedure that the vendors must use to certify the calibrators that meet the qualification specifications. The NIST traceable certification is performance based, traceable to analysis using isotope dilution inductively coupled plasma

  8. QA experience at the University of Wisconsin accredited dosimetry calibration laboratory

    Energy Technology Data Exchange (ETDEWEB)

    DeWard, L.A.; Micka, J.A. [Univ. of Wisconsin, Madison, WI (United States)

    1993-12-31

    The University of Wisconsin Accredited Dosimetry Calibration Laboratory (UW ADCL) employs procedure manuals as part of its Quality Assurance (QA) program. One of these manuals covers the QA procedures and results for all of the UW ADCL measurement equipment. The QA procedures are divided into two main areas: QA for laboratory equipment and QA for external chambers sent for calibration. All internal laboratory equipment is checked and recalibrated on an annual basis, after establishing its consistency on a 6-month basis. QA for external instruments involves checking past calibration history as well as comparing to a range of calibration values for specific instrument models. Generally, the authors find that a chamber will have a variation of less than 0.5 % from previous Co-60 calibration factors, and falls within two standard deviations of previous calibrations. If x-ray calibrations are also performed, the energy response of the chamber is plotted and compared to previous instruments of the same model. These procedures give the authors confidence in the transfer of calibration values from National Institute of Standards and Technology (NIST).

  9. QA experience at the University of Wisconsin accredited dosimetry calibration laboratory

    International Nuclear Information System (INIS)

    DeWard, L.A.; Micka, J.A.

    1993-01-01

    The University of Wisconsin Accredited Dosimetry Calibration Laboratory (UW ADCL) employs procedure manuals as part of its Quality Assurance (QA) program. One of these manuals covers the QA procedures and results for all of the UW ADCL measurement equipment. The QA procedures are divided into two main areas: QA for laboratory equipment and QA for external chambers sent for calibration. All internal laboratory equipment is checked and recalibrated on an annual basis, after establishing its consistency on a 6-month basis. QA for external instruments involves checking past calibration history as well as comparing to a range of calibration values for specific instrument models. Generally, the authors find that a chamber will have a variation of less than 0.5 % from previous Co-60 calibration factors, and falls within two standard deviations of previous calibrations. If x-ray calibrations are also performed, the energy response of the chamber is plotted and compared to previous instruments of the same model. These procedures give the authors confidence in the transfer of calibration values from National Institute of Standards and Technology (NIST)

  10. Performance Assessment and Geometric Calibration of RESOURCESAT-2

    Science.gov (United States)

    Radhadevi, P. V.; Solanki, S. S.; Akilan, A.; Jyothi, M. V.; Nagasubramanian, V.

    2016-06-01

    Resourcesat-2 (RS-2) has successfully completed five years of operations in its orbit. This satellite has multi-resolution and multi-spectral capabilities in a single platform. A continuous and autonomous co-registration, geo-location and radiometric calibration of image data from different sensors with widely varying view angles and resolution was one of the challenges of RS-2 data processing. On-orbit geometric performance of RS-2 sensors has been widely assessed and calibrated during the initial phase operations. Since then, as an ongoing activity, various geometric performance data are being generated periodically. This is performed with sites of dense ground control points (GCPs). These parameters are correlated to the direct geo-location accuracy of the RS-2 sensors and are monitored and validated to maintain the performance. This paper brings out the geometric accuracy assessment, calibration and validation done for about 500 datasets of RS-2. The objectives of this study are to ensure the best absolute and relative location accuracy of different cameras, location performance with payload steering and co-registration of multiple bands. This is done using a viewing geometry model, given ephemeris and attitude data, precise camera geometry and datum transformation. In the model, the forward and reverse transformations between the coordinate systems associated with the focal plane, payload, body, orbit and ground are rigorously and explicitly defined. System level tests using comparisons to ground check points have validated the operational geo-location accuracy performance and the stability of the calibration parameters.

  11. Nuclear fuel technology - Tank calibration and volume determination for nuclear materials accountancy - Part 2: Data standardization for tank calibration

    International Nuclear Information System (INIS)

    2007-01-01

    Measurements of the volume and height of liquid in a process accountancy tank are often made in order to estimate or verify the tank's calibration or volume measurement equation. The calibration equation relates the response of the tank's measurement system to some independent measure of tank volume. The ultimate purpose of the calibration exercise is to estimate the tank's volume measurement equation (the inverse of the calibration equation), which relates tank volume to measurement system response. In this part of ISO 18213, it is assumed that the primary measurement-system response variable is liquid height and that the primary measure of liquid content is volume. This part of ISO 18213 presents procedures for standardizing a set of calibration data to a fixed set of reference conditions so as to minimize the effect of variations in ambient conditions that occur during the measurement process. The procedures presented herein apply generally to measurements of liquid height and volume obtained for the purpose of calibrating a tank (i.e. calibrating a tank's measurement system). When used in connection with other parts of ISO 18213, these procedures apply specifically to tanks equipped with bubbler probe systems for measuring liquid content. The standardization algorithms presented herein can be profitably applied when only estimates of ambient conditions, such as temperature, are available. However, the most reliable results are obtained when relevant ambient conditions are measured for each measurement of volume and liquid height in a set of calibration data. Information is provided on scope, physical principles, data required, calibration data, dimensional changes in the tank, multiple calibration runs and results on standardized calibration data. Four annexes inform about density of water, buoyancy corrections for mass determination, determination of tank heel volume and statistical method for aligning data from several calibration runs. A bibliography is

  12. Ultra-sensitive radionuclide spectrometry. Radiometrics and mass spectrometry synergy

    International Nuclear Information System (INIS)

    Povinec, P.P.

    2005-01-01

    Recent developments in radiometrics and mass spectrometry techniques for ultra-sensitive analysis of radionuclides in the marine environment are reviewed. In the radiometrics sector the dominant development has been the utilization of large HPGe detectors in underground laboratories with anti-cosmic or anti-Compton shielding for the analysis of short and medium-lived radionuclides in the environment. In the mass spectrometry sector, applications of inductively coupled plasma mass spectrometry (ICP-MS) and accelerator mass spectrometry (AMS) for the analysis of long-lived radionuclides in the environment are the most important recent achievements. The recent developments do not only considerably decrease the detection limits for several radionuclides (up to several orders of magnitude), but they also enable to decrease sample volumes so that sampling, e.g., of the water column can be much easier and more effective. A comparison of radiometrics and mass spectrometry results for the analysis of radionuclides in the marine environment shows a reasonable agreement - within quoted uncertainties, for wide range of activities and different sample matrices analyzed. (author)

  13. Procedures for the definitive calibration of radiotherapy equipment

    International Nuclear Information System (INIS)

    1993-01-01

    Recommendations from the Institute of Physical Sciences in Medicine are given for the definition calibration of external beam radiotherapy treatment machines and radiation dose measuring equipment used in radiotherapy. (UK)

  14. Standard Test Method for Calibration of Primary Non-Concentrator Terrestrial Photovoltaic Reference Cells Using a Tabular Spectrum

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method is intended to be used for calibration and characterization of primary terrestrial photovoltaic reference cells to a desired reference spectral irradiance distribution, such as Tables G173. The recommended physical requirements for these reference cells are described in Specification E1040. Reference cells are principally used in the determination of the electrical performance of photovoltaic devices. 1.2 Primary photovoltaic reference cells are calibrated in natural sunlight using the relative spectral response of the cell, the relative spectral distribution of the sunlight, and a tabulated reference spectral irradiance distribution. 1.3 This test method requires the use of a pyrheliometer that is calibrated according to Test Method E816, which requires the use of a pyrheliometer that is traceable to the World Radiometric Reference (WRR). Therefore, reference cells calibrated according to this test method are traceable to the WRR. 1.4 This test method is a technique that may be used ...

  15. Calibration guidelines for surface texture instruments - horizontal axis

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Shem, R. Krüger

    The present report is a documentation of the work carried out at DTU, on TASK 5.1: PROCEDURES FOR CALIBRATION IN X- AND Y- DIRECTION the project with contract SMT4-CT97-2176 with title: Calibration Standards for Surface Topography Measuring Systems down to Nanometric Scale. After a short introduc......The present report is a documentation of the work carried out at DTU, on TASK 5.1: PROCEDURES FOR CALIBRATION IN X- AND Y- DIRECTION the project with contract SMT4-CT97-2176 with title: Calibration Standards for Surface Topography Measuring Systems down to Nanometric Scale. After a short...

  16. Calibration and simulation of Heston model

    Directory of Open Access Journals (Sweden)

    Mrázek Milan

    2017-05-01

    Full Text Available We calibrate Heston stochastic volatility model to real market data using several optimization techniques. We compare both global and local optimizers for different weights showing remarkable differences even for data (DAX options from two consecutive days. We provide a novel calibration procedure that incorporates the usage of approximation formula and outperforms significantly other existing calibration methods.

  17. Multielemental X-ray radiometric analysis of ferromanganese concretions

    International Nuclear Information System (INIS)

    Metelev, A.Yu.; Grigor'ev, A.I.; Rakita, K.A.; Mamaenko, M.V.; Ivanenko, V.V.

    1994-01-01

    Ferromanganese concretions are promising mineral resources of the ocean. Most often, they are analyzed by atomic-absorption, spectra, X-ray spectral, neutron-activation, and X-ray radiometric methods. Note that X-ray radiometric analysis (XRRA) allows the sufficiently rapid determination of a great number of elements in ferromanganese concretions. The possibility of using XRRA with saturated and thin layers was shown; however, the data on the precision and accuracy of the technique was not given. The purpose of this study is to evaluate the basic performance characteristics of the multielemental X-ray radiometric analysis of ferromanganese concretions (Pacific Ocean). Determinations for K,Ca and Ti content were made using a 55 Fe source and for Mn, Fe, Ni, Cu, Zn, Pb, Sr, Y, Zr, Nb, and Mo contents by using a 109 Cd source. The precision and accuracy of the method was investigated by using reference concretions; it was found the confidence intervals overlap for all of the elements except Ca and Pb. The relative standard deviation was 1-5%, indicating the high precision of the method. The described technique is successfully used on research vessels of the Far East Division of the Russian Academy of Sciences and in South Pacific Ocean geological expeditions of PO open-quotes Dal'morgeologiyaclose quotes

  18. Optimized Spectrometers Characterization Procedure for Near Ground Support of ESA FLEX Observations: Part 1 Spectral Calibration and Characterisation

    Directory of Open Access Journals (Sweden)

    Laura Mihai

    2018-02-01

    Full Text Available The paper presents two procedures for the wavelength calibration, in the oxygen telluric absorption spectral bands (O2-A, λc = 687 nm and O2-B, λc = 760.6 nm, of field fixed-point spectrometers used for reflectance and Sun-induced fluorescence measurements. In the first case, Ne and Ar pen-type spectral lamps were employed, while the second approach is based on a double monochromator setup. The double monochromator system was characterized for the estimation of errors associated with different operating configurations. The proposed methods were applied to three Piccolo Doppio-type systems built around two QE Pros and one USB2 + H16355 Ocean Optics spectrometers. The wavelength calibration errors for all the calibrations performed on the three spectrometers are reported and potential methodological improvements discussed. The suggested calibration methods were validated, as the wavelength corrections obtained by both techniques for the QE Pro designed for fluorescence investigations were similar. However, it is recommended that a neon emission line source, as well as an argon or mercury-argon source be used to have a reference wavelength closer to the O2-B feature. The wavelength calibration can then be optimised as close to the O2-B and O2-A features as possible. The monochromator approach could also be used, but that instrument would need to be fully characterized prior to use, and although it may offer a more accurate calibration, as it could be tuned to emit light at the same wavelengths as the absorption features, it would be more time consuming as it is a scanning approach.

  19. Lidar to lidar calibration phase 1

    DEFF Research Database (Denmark)

    Yordanova, Ginka; Courtney, Michael

    This report presents a feasibility study of a lidar to lidar (L2L) calibration procedure. Phase one of the project was conducted at Høvsøre, Denmark. Two windcubes were placed next to the 116m met mast and different methods were applied to obtain the sensing height error of the lidars. The purpose...... is to find the most consistent method and use it in a potential lidar to lidar calibration procedure....

  20. Use of Naturally Available Reference Targets to Calibrate Airborne Laser Scanning Intensity Data

    Directory of Open Access Journals (Sweden)

    Paula Litkey

    2009-04-01

    Full Text Available We have studied the possibility of calibrating airborne laser scanning (ALS intensity data, using land targets typically available in urban areas. For this purpose, a test area around Espoonlahti Harbor, Espoo, Finland, for which a long time series of ALS campaigns is available, was selected. Different target samples (beach sand, concrete, asphalt, different types of gravel were collected and measured in the laboratory. Using tarps, which have certain backscattering properties, the natural samples were calibrated and studied, taking into account the atmospheric effect, incidence angle and flying height. Using data from different flights and altitudes, a time series for the natural samples was generated. Studying the stability of the samples, we could obtain information on the most ideal types of natural targets for ALS radiometric calibration. Using the selected natural samples as reference, the ALS points of typical land targets were calibrated again and examined. Results showed the need for more accurate ground reference data, before using natural samples in ALS intensity data calibration. Also, the NIR camera-based field system was used for collecting ground reference data. This system proved to be a good means for collecting in situ reference data, especially for targets with inhomogeneous surface reflection properties.

  1. Radiometric survey in sampling areas of Itataia mine ore and radiometric monitoring in Itataia project sites

    International Nuclear Information System (INIS)

    1982-07-01

    This radiometric survey was done by CDTN, in Itataia sites, on July/82 and it aimed fundamentally to evaluate local radiological conditions, as for aspect of occupational radiation protection. Besides of results obtained, this report has informations of general aspects that ought to serve as subsidies for elaboration of radiological protection program of local. (author) [pt

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

    Science.gov (United States)

    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.

  3. The perspectives of development of radiometric techniques for welded joints testing

    International Nuclear Information System (INIS)

    Troitskij, V.A.; Dovzhenko, V.N.

    1987-01-01

    The perspectives of development of radiometric techniques in non-destructive testing are presented. The problems of computer tomography, radiometric introscopy, electrorentgenography (xeroradiography) are reviewed. The aspects of application of low-silver detectors are also analysed. The studies on the problems mentioned above will be continued in order to eliminate expensive radiographic films and having in mind making the testing process faster. The design of individual dosemeters is also demonstrated. (author)

  4. Tropospheric and ionospheric media calibrations based on global navigation satellite system observation data

    Science.gov (United States)

    Feltens, Joachim; Bellei, Gabriele; Springer, Tim; Kints, Mark V.; Zandbergen, René; Budnik, Frank; Schönemann, Erik

    2018-06-01

    Context: Calibration of radiometric tracking data for effects in the Earth atmosphere is a crucial element in the field of deep-space orbit determination (OD). The troposphere can induce propagation delays in the order of several meters, the ionosphere up to the meter level for X-band signals and up to tens of meters, in extreme cases, for L-band ones. The use of media calibrations based on Global Navigation Satellite Systems (GNSS) measurement data can improve the accuracy of the radiometric observations modelling and, as a consequence, the quality of orbit determination solutions. Aims: ESOC Flight Dynamics employs ranging, Doppler and delta-DOR (Delta-Differential One-Way Ranging) data for the orbit determination of interplanetary spacecraft. Currently, the media calibrations for troposphere and ionosphere are either computed based on empirical models or, under mission specific agreements, provided by external parties such as the Jet Propulsion Laboratory (JPL) in Pasadena, California. In order to become independent from external models and sources, decision fell to establish a new in-house internal service to create these media calibrations based on GNSS measurements recorded at the ESA tracking sites and processed in-house by the ESOC Navigation Support Office with comparable accuracy and quality. Methods: For its concept, the new service was designed to be as much as possible depending on own data and resources and as less as possible depending on external models and data. Dedicated robust and simple algorithms, well suited for operational use, were worked out for that task. This paper describes the approach built up to realize this new in-house internal media calibration service. Results: Test results collected during three months of running the new media calibrations in quasi-operational mode indicate that GNSS-based tropospheric corrections can remove systematic signatures from the Doppler observations and biases from the range ones. For the ionosphere, a

  5. Modified and reverse radiometric flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Myint, U; Ba, H; Khin, M M; Aung, K; Thida, [Yangon Univ. (Myanmar). Dept. of Chemistry; Toelgyessy, J [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Environmental Science

    1994-06-01

    Determination of [sup 137]Cs and [sup 60]Co by using modified and reverse radiometric flow injection analysis is described. Two component RFIA was also realized using [sup 60]Co and [sup 137]Cs radionuclides. (author) 2 refs.; 5 figs.

  6. Skew redundant MEMS IMU calibration using a Kalman filter

    International Nuclear Information System (INIS)

    Jafari, M; Sahebjameyan, M; Moshiri, B; Najafabadi, T A

    2015-01-01

    In this paper, a novel calibration procedure for skew redundant inertial measurement units (SRIMUs) based on micro-electro mechanical systems (MEMS) is proposed. A general model of the SRIMU measurements is derived which contains the effects of bias, scale factor error and misalignments. For more accuracy, the effect of lever arms of the accelerometers to the center of the table are modeled and compensated in the calibration procedure. Two separate Kalman filters (KFs) are proposed to perform the estimation of error parameters for gyroscopes and accelerometers. The predictive error minimization (PEM) stochastic modeling method is used to simultaneously model the effect of bias instability and random walk noise on the calibration Kalman filters to diminish the biased estimations. The proposed procedure is simulated numerically and has expected experimental results. The calibration maneuvers are applied using a two-axis angle turntable in a way that the persistency of excitation (PE) condition for parameter estimation is met. For this purpose, a trapezoidal calibration profile is utilized to excite different deterministic error parameters of the accelerometers and a pulse profile is used for the gyroscopes. Furthermore, to evaluate the performance of the proposed KF calibration method, a conventional least squares (LS) calibration procedure is derived for the SRIMUs and the simulation and experimental results compare the functionality of the two proposed methods with each other. (paper)

  7. Efficient mass calibration of magnetic sector mass spectrometers

    International Nuclear Information System (INIS)

    Roddick, J.C.

    1996-01-01

    Magnetic sector mass spectrometers used for automatic acquisition of precise isotopic data are usually controlled with Hall probes and software that uses polynomial equations to define and calibrate the mass-field relations required for mass focusing. This procedure requires a number of reference masses and careful tuning to define and maintain an accurate mass calibration. A simplified equation is presented and applied to several different magnetically controlled mass spectrometers. The equation accounts for nonlinearity in typical Hall probe controlled mass-field relations, reduces calibration to a linear fitting procedure, and is sufficiently accurate to permit calibration over a mass range of 2 to 200 amu with only two defining masses. Procedures developed can quickly correct for normal drift in calibrations and compensate for drift during isotopic analysis over a limited mass range such as a single element. The equation is: Field A·Mass 1/2 + B·(Mass) p where A, B, and p are constants. The power value p has a characteristic value for a Hall probe/controller and is insensitive to changing conditions, thus reducing calibration to a linear regression to determine optimum A and B. (author). 1 ref., 1 tab., 6 figs

  8. Band-to-Band Misregistration of the Images of MODIS Onboard Calibrators and Its Impact on Calibration

    Science.gov (United States)

    Wang, Zhipeng; Xiong, Xiaoxiong

    2017-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard Terra and Aqua satellites are radiometrically calibrated on-orbit with a set of onboard calibrators (OBCs), including a solar diffuser, a blackbody, and a space view port through which the detectors can view the dark space. As a whisk-broom scanning spectroradiometer, thirty-six MODIS spectral bands are assembled in the along-scan direction on four focal plane assemblies (FPAs). These bands capture images of the same target sequentially with the motion of a scan mirror. Then the images are coregistered onboard by delaying the appropriate band-dependent amount of time, depending on the band locations on the FPA. While this coregistration mechanismis functioning well for the far-field remote targets such as earth view scenes or the moon, noticeable band-to-band misregistration in the along-scan direction has been observed for near field targets, particularly in OBCs. In this paper, the misregistration phenomenon is presented and analyzed. It is concluded that the root cause of the misregistration is that the rotating element of the instrument, the scan mirror, is displaced from the focus of the telescope primary mirror. The amount of the misregistrationis proportional to the band location on the FPA and is inversely proportional to the distance between the target and the scan mirror. The impact of this misregistration on the calibration of MODIS bands is discussed. In particular, the calculation of the detector gain coefficient m1of bands 8-16 (412 nm 870 nm) is improved by up to 1.5% for Aqua MODIS.

  9. Fermentation process tracking through enhanced spectral calibration modeling.

    Science.gov (United States)

    Triadaphillou, Sophia; Martin, Elaine; Montague, Gary; Norden, Alison; Jeffkins, Paul; Stimpson, Sarah

    2007-06-15

    The FDA process analytical technology (PAT) initiative will materialize in a significant increase in the number of installations of spectroscopic instrumentation. However, to attain the greatest benefit from the data generated, there is a need for calibration procedures that extract the maximum information content. For example, in fermentation processes, the interpretation of the resulting spectra is challenging as a consequence of the large number of wavelengths recorded, the underlying correlation structure that is evident between the wavelengths and the impact of the measurement environment. Approaches to the development of calibration models have been based on the application of partial least squares (PLS) either to the full spectral signature or to a subset of wavelengths. This paper presents a new approach to calibration modeling that combines a wavelength selection procedure, spectral window selection (SWS), where windows of wavelengths are automatically selected which are subsequently used as the basis of the calibration model. However, due to the non-uniqueness of the windows selected when the algorithm is executed repeatedly, multiple models are constructed and these are then combined using stacking thereby increasing the robustness of the final calibration model. The methodology is applied to data generated during the monitoring of broth concentrations in an industrial fermentation process from on-line near-infrared (NIR) and mid-infrared (MIR) spectrometers. It is shown that the proposed calibration modeling procedure outperforms traditional calibration procedures, as well as enabling the identification of the critical regions of the spectra with regard to the fermentation process.

  10. Multitemporal cross-calibration of the Terra MODIS and Landsat 7 ETM+ reflective solar bands

    Science.gov (United States)

    Angal, Amit; Xiong, Xiaoxiong; Wu, Aisheng; Chander, Gyanesh; Choi, Taeyoung

    2013-01-01

    In recent years, there has been a significant increase in the use of remotely sensed data to address global issues. With the open data policy, the data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Enhanced Thematic Mapper Plus (ETM+) sensors have become a critical component of numerous applications. These two sensors have been operational for more than a decade, providing a rich archive of multispectral imagery for analysis of mutitemporal remote sensing data. This paper focuses on evaluating the radiometric calibration agreement between MODIS and ETM+ using the near-simultaneous and cloud-free image pairs over an African pseudo-invariant calibration site, Libya 4. To account for the combined uncertainties in the top-of-atmosphere (TOA) reflectance due to surface and atmospheric bidirectional reflectance distribution function (BRDF), a semiempirical BRDF model was adopted to normalize the TOA reflectance to the same illumination and viewing geometry. In addition, the spectra from the Earth Observing-1 (EO-1) Hyperion were used to compute spectral corrections between the corresponding MODIS and ETM+ spectral bands. As EO-1 Hyperion scenes were not available for all MODIS and ETM+ data pairs, MODerate resolution atmospheric TRANsmission (MODTRAN) 5.0 simulations were also used to adjust for differences due to the presence or lack of absorption features in some of the bands. A MODIS split-window algorithm provides the atmospheric water vapor column abundance during the overpasses for the MODTRAN simulations. Additionally, the column atmospheric water vapor content during the overpass was retrieved using the MODIS precipitable water vapor product. After performing these adjustments, the radiometric cross-calibration of the two sensors was consistent to within 7%. Some drifts in the response of the bands are evident, with MODIS band 3 being the largest of about 6% over 10 years, a change that will be corrected in Collection 6 MODIS processing.

  11. Continuous Calibration Improvement in Solar Reflective Bands: Landsat 5 Through Landsat 8

    Science.gov (United States)

    Mishra, Nischal; Helder, Dennis; Barsi, Julia; Markham, Brian

    2016-01-01

    Launched in February 2013, the Operational Land Imager (OLI) on-board Landsat 8 continues to perform exceedingly well and provides high science quality data globally. Several design enhancements have been made in the OLI instrument relative to prior Landsat instruments: pushbroom imaging which provides substantially improved Signal-to-Noise Ratio (SNR), spectral bandpasses refinement to avoid atmospheric absorption features, 12 bit data resolution to provide a larger dynamic range that limits the saturation level, a set of well-designed onboard calibrators to monitor the stability of the sensor. Some of these changes such as refinements in spectral bandpasses compared to earlier Landsats and well-designed on-board calibrator have a direct impact on the improved radiometric calibration performance of the instrument from both the stability of the response and the ability to track the changes. The on-board calibrator lamps and diffusers indicate that the instrument drift is generally less than 0.1% per year across the bands. The refined bandpasses of the OLI indicate that temporal uncertainty of better than 0.5% is possible when the instrument is trended over vicarious targets such as Pseudo Invariant Calibration Sites (PICS), a level of precision that was never achieved with the earlier Landsat instruments. The stability measurements indicated by on-board calibrators and PICS agree much better compared to the earlier Landsats, which is very encouraging and bodes well for the future Landsat missions too.

  12. A methodology for calibration of hyperspectral and multispectral satellite data in coastal areas

    Science.gov (United States)

    Pennucci, Giuliana; Fargion, Giulietta; Alvarez, Alberto; Trees, Charles; Arnone, Robert

    2012-06-01

    The objective of this work is to determine the location(s) in any given oceanic area during different temporal periods where in situ sampling for Calibration/Validation (Cal/Val) provides the best capability to retrieve accurate radiometric and derived product data (lowest uncertainties). We present a method to merge satellite imagery with in situ measurements, to determine the best in situ sampling strategy suitable for satellite Cal/Val and to evaluate the present in situ locations through uncertainty indices. This analysis is required to determine if the present in situ sites are adequate for assessing uncertainty and where additional sites and ship programs should be located to improve Calibration/Validation (Cal/Val) procedures. Our methodology uses satellite acquisitions to build a covariance matrix encoding the spatial-temporal variability of the area of interest. The covariance matrix is used in a Bayesian framework to merge satellite and in situ data providing a product with lower uncertainty. The best in situ location for Cal/Val is then identified by using a design principle (A-optimum design) that looks for minimizing the estimated variance of the merged products. Satellite products investigated in this study include Ocean Color water leaving radiance, chlorophyll, and inherent and apparent optical properties (retrieved from MODIS and VIIRS). In situ measurements are obtained from systems operated on fixed deployment platforms (e.g., sites of the Ocean Color component of the AErosol RObotic NETwork- AERONET-OC), moorings (e.g, Marine Optical Buoy-MOBY), ships or autonomous vehicles (such as Autonomous Underwater Vehicles and/or Gliders).

  13. Radiometric and dosimetric characteristics of HgI2 detectors

    International Nuclear Information System (INIS)

    Zaletin, V.M.; Krivozubov, O.V.; Torlin, M.A.; Fomin, V.I.

    1988-01-01

    The characteristics of HgI 2 detectors in x-ray and gamma detection in applications to radiometric and dosimetric monitoring and as portable instruments for such purposes was considered. Blocks with mosaic and sandwich structures were prepared and tested against each other and, for comparative purposes, against CdTe detectors for relative sensitivities at various gamma-quanta energies. Sensitivity dependencies on gamma radiation energy were plotted for the detector materials and structures as were current dependencies on the dose rate of x rays. Results indicated that the mercury iodide detectors could be used in radiometric and dosimetric measurements at gamma quantum energies up to and in excess of 1000 KeV

  14. Calibration/Validation Error Budgets, Uncertainties, Traceability and Their Importance to Imaging Spectrometry

    Science.gov (United States)

    Thome, K.

    2016-01-01

    Knowledge of uncertainties and errors are essential for comparisons of remote sensing data across time, space, and spectral domains. Vicarious radiometric calibration is used to demonstrate the need for uncertainty knowledge and to provide an example error budget. The sample error budget serves as an example of the questions and issues that need to be addressed by the calibrationvalidation community as accuracy requirements for imaging spectroscopy data will continue to become more stringent in the future. Error budgets will also be critical to ensure consistency between the range of imaging spectrometers expected to be launched in the next five years.

  15. Discrepancy between growth of Coccidioides immitis in bacterial blood culture media and a radiometric growth index

    International Nuclear Information System (INIS)

    Ampel, N.M.; Wieden, M.A.

    1988-01-01

    Spherules of Coccidioides immitis grew readily after inoculation in vented trypticase soy broth, biphasic brain heart infusion media, and aerobic tryptic soy broth bottles used in a radiometric system (BACTEC). However, visible growth was not accompanied by a significant radiometric growth index. Growth of C. immitis can be visually detected in routine bacterial blood culture media while the radiometric growth index remains negative

  16. Evaluation of the Use of Dark and Bright Targets for the In-Flight Calibration of AVIRIS

    Science.gov (United States)

    Thome, K.; Parada, R.; Schiller, S.; Conel, J.; LaMarr, J.

    1998-01-01

    During a field campaign at Lake Tahoe on June 22, 1995, calibrations of AVIRIS were attempted using both the reflectance-based and radiance-based methods. This experiment shows that the use of dark water targets to calibrate radiometric sensors can result in meaningful sensor characterization. In particular, the reflectance-based method shows promise towards meeting the desired 2-3% uncertainty levels for ocean color sensors since experimental agreement of better than 1.5% is found for the Lake Tahoe AVIRIS experiment. Similarly promising results were found from reflectance-based calibrations at Lunar Lake with large portions of the spectrum having less than a 5% difference between the reflectance-based predictions and the measured AVIRIS radiances. These results are still in the preliminary stage and it is likely that further study of this data set will lead to even better agreement. The results of the radiance-based calibration at Lake Tahoe are quite good at the shorter wavelengths where atmospheric scattering leads to larger signals and smaller effects of specularly reflected solar energy. The results also showed the sensitivity to radiometer pointing when using water targets for vicarious calibration.

  17. PERFORMANCE ASSESSMENT AND GEOMETRIC CALIBRATION OF RESOURCESAT-2

    Directory of Open Access Journals (Sweden)

    P. V. Radhadevi

    2016-06-01

    Full Text Available Resourcesat-2 (RS-2 has successfully completed five years of operations in its orbit. This satellite has multi-resolution and multi-spectral capabilities in a single platform. A continuous and autonomous co-registration, geo-location and radiometric calibration of image data from different sensors with widely varying view angles and resolution was one of the challenges of RS-2 data processing. On-orbit geometric performance of RS-2 sensors has been widely assessed and calibrated during the initial phase operations. Since then, as an ongoing activity, various geometric performance data are being generated periodically. This is performed with sites of dense ground control points (GCPs. These parameters are correlated to the direct geo-location accuracy of the RS-2 sensors and are monitored and validated to maintain the performance. This paper brings out the geometric accuracy assessment, calibration and validation done for about 500 datasets of RS-2. The objectives of this study are to ensure the best absolute and relative location accuracy of different cameras, location performance with payload steering and co-registration of multiple bands. This is done using a viewing geometry model, given ephemeris and attitude data, precise camera geometry and datum transformation. In the model, the forward and reverse transformations between the coordinate systems associated with the focal plane, payload, body, orbit and ground are rigorously and explicitly defined. System level tests using comparisons to ground check points have validated the operational geo-location accuracy performance and the stability of the calibration parameters.

  18. In-vessel calibration of the imaging diagnostics for the real-time protection of the JET ITER-like wall

    Energy Technology Data Exchange (ETDEWEB)

    Huber, V., E-mail: V.Huber@fz-juelich.de [Forschungszentrum Jülich GmbH, Supercomputing Centre, 52425 Jülich (Germany); Huber, A.; Mertens, Ph.; Sergienko, G. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung—Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich (Germany); Kinna, D.; Balboa, I.; Collins, S.; Conway, N.; Maggi, C. F.; Matthews, G. F.; Meigs, A. G.; Price, M.; Silburn, S.; Zastrow, K.-D. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Drewelow, P. [MPI für Plasmaphysik, Greifswald (Germany); Wynn, A. [York Plasma Institute, University of York, Heslington, York YO10 5DD (United Kingdom)

    2016-11-15

    The in situ absolute calibration of the JET real-time protection imaging system has been performed for the first time by means of radiometric light source placed inside the JET vessel and operated by remote handling. High accuracy of the calibration is confirmed by cross-validation of the near infrared (NIR) cameras against each other, with thermal IR cameras, and with the beryllium evaporator, which lead to successful protection of the JET first wall during the last campaign. The operation temperature ranges of NIR protection cameras for the materials used on JET are Be 650-1600 °C, W coating 600-1320 °C, and W 650-1500 °C.

  19. Radiometric determination of monoethanolamine with /sup 65/ZnSo/sub 4/

    Energy Technology Data Exchange (ETDEWEB)

    Varadan, R; Sriman Narayanan, S; Rao, V R.S. [Indian Inst. of Tech., Bombay. Dept. of Chemistry

    1984-05-07

    Determination of milligram amounts of monoethanolamine (MEA) with zinc(II) by radiometric titration is described. When MEA is added to a zinc(II) solution containing sulphate ions at 25 degC, a white solid complex is formed. The formation of this complex is employed for the radiometric determination of MEA with /sup 65/Zn. The amount of MEA is directly proportional to the activity of the complex formed. The method is simple, rapid and accurate. 8 refs.

  20. Radiometric and signal-to-noise ratio properties of multiplex dispersive spectrometry

    International Nuclear Information System (INIS)

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

    2010-01-01

    Recent theoretical investigations have shown important radiometric disadvantages of interferential multiplexing in Fourier transform spectrometry that apparently can be applied even to coded aperture spectrometers. We have reexamined the methods of noninterferential multiplexing in order to assess their signal-to-noise ratio (SNR) performance, relying on a theoretical modeling of the multiplexed signals. We are able to show that quite similar SNR and radiometric disadvantages affect multiplex dispersive spectrometry. The effect of noise on spectral estimations is discussed.

  1. Simulating SiD Calorimetry: Software Calibration Procedures and Jet Energy Resolution

    International Nuclear Information System (INIS)

    Cassell, R.

    2009-01-01

    Simulated calorimeter performance in the SiD detector is examined. The software calibration procedures are described, as well as the perfect pattern recognition PFA reconstruction. Performance of the SiD calorimeters is summarized with jet energy resolutions from calorimetry only, perfect pattern recognition and the SiD PFA algorithm. Presented at LCWS08(1). Our objective is to simulate the calorimeter performance of the SiD detector, with and without a Particle Flow Algorithm (PFA). Full Geant4 simulations using SLIC(2) and the SiD simplified detector geometry (SiD02) are used. In this geometry, the calorimeters are represented as layered cylinders. The EM calorimeter is Si/W, with 20 layers of 2.5mm W and 10 layers of 5mm W, segmented in 3.5 x 3.5mm 2 cells. The HAD calorimeter is RPC/Fe, with 40 layers of 20mm Fe and a digital readout, segmented in 10 x 10mm 2 cells. The barrel detectors are layered in radius, while the endcap detectors are layered in z(along the beam axis)

  2. Submicron beam X-ray diffraction of nanoheteroepitaxily grown GaN: Experimental challenges and calibration procedures

    Energy Technology Data Exchange (ETDEWEB)

    Bonanno, P.L., E-mail: PeterBonanno@gatech.ed [Georgia Institute of Technology/GTL, UMI 2958 Georgia Tech-CNRS, 57070 Metz (France); Gautier, S. [Laboratoire Materiaux Optiques, Photonique et Micro-Nano Systemes, UMR CNRS 7132, Universite de Metz et SUPELEC, 2 rue E. Belin, 57070 Metz (France); Sirenko, A.A. [Department of Physics, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Kazimirov, A. [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, New York 14853 (United States); Cai, Z.-H. [Advanced Photon Source, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Goh, W.H. [Georgia Institute of Technology/GTL, UMI 2958 Georgia Tech-CNRS, 57070 Metz (France); Martin, J. [Laboratoire Materiaux Optiques, Photonique et Micro-Nano Systemes, UMR CNRS 7132, Universite de Metz et SUPELEC, 2 rue E. Belin, 57070 Metz (France); Martinez, A. [Laboratoire de Photonique et de Nanostructures, UPR CNRS 20, Route de Nozay, 91460 Marcoussis (France); Moudakir, T. [Laboratoire Materiaux Optiques, Photonique et Micro-Nano Systemes, UMR CNRS 7132, Universite de Metz et SUPELEC, 2 rue E. Belin, 57070 Metz (France); Maloufi, N. [Laboratoire d' Etude des Textures et Application aux Materiaux, UMR CNRS 7078, Ile du Saulcy, 57045 Metz Cedex 1 (France); Assouar, M.B. [Laboratoire de Physique des Milieux Ionises et Applications, Nancy University, CNRS, BP 239, F-54506 Vandoeuvre-les-Nancy Cedex (France); Ramdane, A.; Gratiet, L. Le [Laboratoire de Photonique et de Nanostructures, UPR CNRS 20, Route de Nozay, 91460 Marcoussis (France); Ougazzaden, A. [Georgia Institute of Technology/GTL, UMI 2958 Georgia Tech-CNRS, 57070 Metz (France)

    2010-02-15

    Highly relaxed GaN nanodots and submicron ridges have been selectively grown in the NSAG regime using MOVPE on lattice mismatched 6H-SiC and AlN substrates. 2D real space and 3D reciprocal space mapping was performed with a CCD detector using 10.4 keV synchrotron X-ray radiation at the 2-ID-D micro-diffraction beamline at Advanced Photon Source (APS). Calibration procedures have been developed to overcome the unique challenges of analyzing NSAG structures grown on highly mismatched substrates. We studied crystallographic planar bending on the submicron scale and found its correlation with strain relaxation in the NSAG ridges.

  3. Data processing and in-flight calibration systems for OMI-EOS-Aura

    Science.gov (United States)

    van den Oord, G. H. J.; Dobber, M.; van de Vegte, J.; van der Neut, I.; Som de Cerff, W.; Rozemeijer, N. C.; Schenkelaars, V.; ter Linden, M.

    2006-08-01

    The OMI instrument that flies on the EOS Aura mission was launched in July 2004. OMI is a UV-VIS imaging spectrometer that measures in the 270 - 500 nm wavelength range. OMI provides daily global coverage with high spatial resolution. Every orbit of 100 minutes OMI generates about 0.5 GB of Level 0 data and 1.2 GB of Level 1 data. About half of the Level 1 data consists of in-flight calibration measurements. These data rates make it necessary to automate the process of in-flight calibration. For that purpose two facilities have been developed at KNMI in the Netherlands: the OMI Dutch Processing System (ODPS) and the Trend Monitoring and In-flight Calibration Facility (TMCF). A description of these systems is provided with emphasis on the use for radiometric, spectral and detector calibration and characterization. With the advance of detector technology and the need for higher spatial resolution, data rates will become even higher for future missions. To make effective use of automated systems like the TMCF, it is of paramount importance to integrate the instrument operations concept, the information contained in the Level 1 (meta-)data products and the inflight calibration software and system databases. In this way a robust but also flexible end-to-end system can be developed that serves the needs of the calibration staff, the scientific data users and the processing staff. The way this has been implemented for OMI may serve as an example of a cost-effective and user friendly solution for future missions. The basic system requirements for in-flight calibration are discussed and examples are given how these requirements have been implemented for OMI. Special attention is paid to the aspect of supporting the Level 0 - 1 processing with timely and accurate calibration constants.

  4. Efficient mass calibration of magnetic sector mass spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Roddick, J C

    1997-12-31

    Magnetic sector mass spectrometers used for automatic acquisition of precise isotopic data are usually controlled with Hall probes and software that uses polynomial equations to define and calibrate the mass-field relations required for mass focusing. This procedure requires a number of reference masses and careful tuning to define and maintain an accurate mass calibration. A simplified equation is presented and applied to several different magnetically controlled mass spectrometers. The equation accounts for nonlinearity in typical Hall probe controlled mass-field relations, reduces calibration to a linear fitting procedure, and is sufficiently accurate to permit calibration over a mass range of 2 to 200 amu with only two defining masses. Procedures developed can quickly correct for normal drift in calibrations and compensate for drift during isotopic analysis over a limited mass range such as a single element. The equation is: Field A{center_dot}Mass{sup 1/2} + B{center_dot}(Mass){sup p} where A, B, and p are constants. The power value p has a characteristic value for a Hall probe/controller and is insensitive to changing conditions, thus reducing calibration to a linear regression to determine optimum A and B. (author). 1 ref., 1 tab., 6 figs.

  5. Instrumentation calibration

    International Nuclear Information System (INIS)

    Mack, D.A.

    1976-08-01

    Procedures for the calibration of different types of laboratory equipment are described. Provisions for maintaining the integrity of reference and working standards traceable back to a national standard are discussed. Methods of validation and certification methods are included. An appendix lists available publications and services of national standardizing agencies

  6. Band-to-Band Misregistration of the Images of MODIS On-Board Calibrators and Its Impact to Calibration

    Science.gov (United States)

    Wang, Zhipeng; Xiong, Xiaoxiong

    2017-01-01

    The MODIS instruments aboard Terra and Aqua satellites are radiometrically calibrated on-orbit with a set of onboard calibrators (OBC) including a solar diffuser (SD), a blackbody (BB) and a space view (SV) port through which the detectors can view the dark space. As a whisk-broom scanning spectroradiometer, thirty-six MODIS spectral bands are assembled in the along-scan direction on four focal plane assemblies (FPA). These bands capture images of the same target sequentially with the motion of a scan mirror. Then the images are co-registered on board by delaying appropriate band dependent amount of time depending on the band locations on the FPA. While this co-registration mechanism is functioning well for the "far field" remote targets such as Earth view (EV) scenes or the Moon, noticeable band-to-band misregistration in the along-scan direction has been observed for near field targets, in particular the OBCs. In this paper, the misregistration phenomenon is presented and analyzed. It is concluded that the root cause of the misregistration is that the rotating element of the instrument, the scan mirror, is displaced from the focus of the telescope primary mirror. The amount of the misregistration is proportional to the band location on the FPA and is inversely proportional to the distance between the target and the scan mirror. The impact of this misregistration to the calibration of MODIS bands is discussed. In particular, the calculation of the detector gain coefficient m1 of bands 8-16 (412 nm 870 nm) is improved by up to 1.5% for Aqua MODIS.

  7. Radiometric measuring method for egg shells

    Energy Technology Data Exchange (ETDEWEB)

    Forberg, S; Svaerdstroem, K

    1973-02-01

    A description is given of a fast nondestructive radiometric method for registration of the thickness of egg shells of the tawny owl, hen, osprey, and Canada goose. Certain errors are discussed. Measurement of the thickness of egg shells (mineral content per cm/sup 2/) with an accuracy better than 1% is possible in less than one minute under field conditions. (auth)

  8. Standard operational radiation protection instructions for process instrumentation and control engineering applying radiometric equipment containing sealed sources

    International Nuclear Information System (INIS)

    1989-01-01

    According to article 16(3) of the Ordinance on the Implementation of Atomic Safety and Radiation Protection of 11 October 1984, operational radiation protection instructions have to be worked out for each type of nuclear energy application. Based on the valid legal provisions of the GDR and on experience and knowledge gained in practice, the most important operational instructions and procedures for the operation of radiometric equipment containing sealed sources were compiled. The example should enable the management to make the instructions directly applicable and, if necessary, to modify or supplement them

  9. An Investigation of a Novel Cross-Calibration Method of FY-3C/VIRR against NPP/VIIRS in the Dunhuang Test Site

    Directory of Open Access Journals (Sweden)

    Caixia Gao

    2016-01-01

    Full Text Available Radiometric cross-calibration of Earth observation sensors is an effective approach to evaluate instrument calibration performance, identify and diagnose calibration anomalies, and quantify the consistency of measurements from different sensors. In this study a novel cross-calibration method is proposed, taking into account the spectral and viewing angle differences adequately; the method is applied to the FY-3C/Visible Infrared Radiometer (VIRR, taking the Suomi National Polar-Orbiting Partnership (NPP/Visible Infrared Imaging Radiometer Suite (VIIRS as a reference. The results show that the relative difference between the two sets increases from January to May 2014, and becomes lower for the data on 24 July, 11 September, and 16 September, within approximately 10%. This phenomenon is caused by the updating of the calibration coefficients in the VIRR datasets with results from a vicarious method on June 2014. After performing an approximate estimation of the uncertainty, it is demonstrated that this calibration has a total uncertainty of 5.5%–6.0%, which is mainly from the uncertainty of the Bidirectional Reflectance Distribution Function model.

  10. Calibration of well-type ionization chambers

    International Nuclear Information System (INIS)

    Alves, C.F.E.; Leite, S.P.; Pires, E.J.; Magalhaes, L.A.G.; David, M.G.; Almeida, C.E. de

    2015-01-01

    This paper presents the methodology developed by the Laboratorio de Ciencias Radiologicas and presently in use for determining of the calibration coefficient for well-type chambers used in the dosimetry of 192 Ir high dose rate sources. Uncertainty analysis involving the calibration procedure are discussed. (author)

  11. Radiometric microbiologic assay for the biologically active forms of niacin

    International Nuclear Information System (INIS)

    Kertcher, J.A.; Guilarte, T.R.; Chen, M.F.; Rider, A.A.; McIntyre, P.A.

    1979-01-01

    A radiometric microbiologic assay has been developed for the determination of niacin in biologic fluids. Lactobacillus plantarum produced 14 CO 2 from L-[U- 14 C] malic acid in quantities proportional to the amount of niacin present. The assay is specific for the biologically active forms of niacin in humans. Thirty normal hemolysates were analyzed and the values ranged from 13.0 to 17.8 μg niacin/ml RBC (mean = 15.27 +- 1.33 s.d.). Good recovery and reproducibility studies were obtained with this assay. On thirty blood samples, correlation was excellent between the radiometric and the conventional turbidimetric assays

  12. Calibrations of a tritium extraction facility

    International Nuclear Information System (INIS)

    Bretscher, M.M.; Oliver, B.M.; Farrar, H. IV.

    1983-01-01

    A tritium extraction facility has been built for the purpose of measuring the absolute tritium concentration in neutron-irradiated lithium metal samples. Two independent calibration procedures have been used to determine what fraction, if any, of tritium is lost during the extraction process. The first procedure compares independently measured 4 He and 3 H concentrations from the 6 Li(n,α)T reaction. The second procedure compared measured 6 Li(n,α)T/ 197 Au (n,γ) 198 Au thermal neutron reaction rate ratios with those obtained from Monte Carlo calculations using well-known cross sections. Both calibration methods show that within experimental errors (approx. 1.5%) no tritium is lost during the extraction process

  13. SU-E-T-749: Thorough Calibration of MOSFET Dosimeters

    International Nuclear Information System (INIS)

    Plenkovich, D; Thomas, J

    2015-01-01

    Purpose: To improve the accuracy of the MOSFET calibration procedure by performing the measurement several times and calculating the average value of the calibration factor for various photon and electron energies. Methods: The output of three photon and six electron beams of Varian Trilogy linear accelerator SN 5878 was calibrated. Five reinforced standard sensitivity MOSFET dosimeters were placed in the calibration jig and connected to the Reader Module. As the backscatter material was used 7 cm of Virtual Water. The MOSFET dosimeters were covered with 1.5 cm thick bolus for the regular and SRS 6 MV beams, 3 cm bolus for 15 MV beam, 1.5 cm bolus for 6 MeV electron beam, and 2 cm bolus for the electron energies of 9, 12, 15, 18, and 22 MeV. The dosimeters were exposed to 100 MU, and the calibration factor was determined using the mobileMOSFET software. To improve the accuracy of calibration, this procedure was repeated ten times and the calibration factors were averaged. Results: As the number of calibrations was increasing the variability of calibration factors of different dosimeters was decreasing. After ten calibrations, the calibration factors for all five dosimeters were within 1% of one another for all energies, except 6 MV SRS photons and 6 MeV electrons, for which the variability was 2%. Conclusions: The described process results in calibration factors which are almost independent of modality or energy. Once calibrated, the dosimeters may be used for in-vivo dosimetry or for daily verification of the beam output. Measurement of the radiation dose under bolus and scatter to the eye are examples of frequent use of calibrated MOSFET dosimeters. The calibration factor determined for full build-up is used under these circumstances. To the best of our knowledge, such thorough procedure for calibrating MOSFET dosimeters has not been reported previously. Best Medical Canada provided MOSFET dosimeters for this project

  14. Calibration and intercomparison methods of dose calibrators used in nuclear medicine facilities; Metodos de calibracao e de intercomparacao de calibradores de dose utilizados em servicos de medicina nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Alessandro Martins da

    1999-07-01

    Dose calibrators are used in most of the nuclear medicine facilities to determine the amount of radioactivity administered to a patient in a particular investigation or therapeutic procedure. It is therefore of vital importance that the equipment used presents good performance and is regular;y calibrated at a authorized laboratory. This occurs of adequate quality assurance procedures are carried out. Such quality control tests should be performed daily, other biannually or yearly, testing, for example, its accuracy and precision, the reproducibility and response linearity. In this work a commercial dose calibrator was calibrated with solution of radionuclides used in nuclear medicine. Simple instrument tests, such as response linearity and the response variation of the source volume increase at a constant source activity concentration, were performed. This instrument can now be used as a working standard for calibration of other dose calibrators/ An intercomparison procedure was proposed as a method of quality control of dose calibrators used in nuclear medicine facilities. (author)

  15. Automated radioanalytical system incorporating microwave-assisted sample preparation, chemical separation, and online radiometric detection for the monitoring of total 99Tc in nuclear waste processing streams.

    Science.gov (United States)

    Egorov, Oleg B; O'Hara, Matthew J; Grate, Jay W

    2012-04-03

    An automated fluidic instrument is described that rapidly determines the total (99)Tc content of aged nuclear waste samples, where the matrix is chemically and radiologically complex and the existing speciation of the (99)Tc is variable. The monitor links microwave-assisted sample preparation with an automated anion exchange column separation and detection using a flow-through solid scintillator detector. The sample preparation steps acidify the sample, decompose organics, and convert all Tc species to the pertechnetate anion. The column-based anion exchange procedure separates the pertechnetate from the complex sample matrix, so that radiometric detection can provide accurate measurement of (99)Tc. We developed a preprogrammed spike addition procedure to automatically determine matrix-matched calibration. The overall measurement efficiency that is determined simultaneously provides a self-diagnostic parameter for the radiochemical separation and overall instrument function. Continuous, automated operation was demonstrated over the course of 54 h, which resulted in the analysis of 215 samples plus 54 hly spike-addition samples, with consistent overall measurement efficiency for the operation of the monitor. A sample can be processed and measured automatically in just 12.5 min with a detection limit of 23.5 Bq/mL of (99)Tc in low activity waste (0.495 mL sample volume), with better than 10% RSD precision at concentrations above the quantification limit. This rapid automated analysis method was developed to support nuclear waste processing operations planned for the Hanford nuclear site.

  16. SMAP RADAR Calibration and Validation

    Science.gov (United States)

    West, R. D.; Jaruwatanadilok, S.; Chaubel, M. J.; Spencer, M.; Chan, S. F.; Chen, C. W.; Fore, A.

    2015-12-01

    The Soil Moisture Active Passive (SMAP) mission launched on Jan 31, 2015. The mission employs L-band radar and radiometer measurements to estimate soil moisture with 4% volumetric accuracy at a resolution of 10 km, and freeze-thaw state at a resolution of 1-3 km. Immediately following launch, there was a three month instrument checkout period, followed by six months of level 1 (L1) calibration and validation. In this presentation, we will discuss the calibration and validation activities and results for the L1 radar data. Early SMAP radar data were used to check commanded timing parameters, and to work out issues in the low- and high-resolution radar processors. From April 3-13 the radar collected receive only mode data to conduct a survey of RFI sources. Analysis of the RFI environment led to a preferred operating frequency. The RFI survey data were also used to validate noise subtraction and scaling operations in the radar processors. Normal radar operations resumed on April 13. All radar data were examined closely for image quality and calibration issues which led to improvements in the radar data products for the beta release at the end of July. Radar data were used to determine and correct for small biases in the reported spacecraft attitude. Geo-location was validated against coastline positions and the known positions of corner reflectors. Residual errors at the time of the beta release are about 350 m. Intra-swath biases in the high-resolution backscatter images are reduced to less than 0.3 dB for all polarizations. Radiometric cross-calibration with Aquarius was performed using areas of the Amazon rain forest. Cross-calibration was also examined using ocean data from the low-resolution processor and comparing with the Aquarius wind model function. Using all a-priori calibration constants provided good results with co-polarized measurements matching to better than 1 dB, and cross-polarized measurements matching to about 1 dB in the beta release. During the

  17. Radiometric relations of a sugarcane crop

    International Nuclear Information System (INIS)

    Machado, E.C.; Pereira, A.R.; Camargo, M.B.P. de; Fahl, J.I.

    1985-01-01

    The radiometric relations of a sugarcane crop, cv. NA56-79, are studied during the period of maximum leaf area index. The coefficients of reflection, transmission and absorption of the incoming solar radiation were function of solar elevation and the waveband considered. The photosynthetically active radiation was always less reflected and transmitted but more absorved than the near infrared radiation. (M.A.C.) [pt

  18. 40 CFR 1065.315 - Pressure, temperature, and dewpoint calibration.

    Science.gov (United States)

    2010-07-01

    ...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calibrations and Verifications Measurement of Engine... temperature-equilibrated and temperature-monitored calibration salt solutions in containers that seal...

  19. Increased Automation in Stereo Camera Calibration Techniques

    Directory of Open Access Journals (Sweden)

    Brandi House

    2006-08-01

    Full Text Available Robotic vision has become a very popular field in recent years due to the numerous promising applications it may enhance. However, errors within the cameras and in their perception of their environment can cause applications in robotics to fail. To help correct these internal and external imperfections, stereo camera calibrations are performed. There are currently many accurate methods of camera calibration available; however, most or all of them are time consuming and labor intensive. This research seeks to automate the most labor intensive aspects of a popular calibration technique developed by Jean-Yves Bouguet. His process requires manual selection of the extreme corners of a checkerboard pattern. The modified process uses embedded LEDs in the checkerboard pattern to act as active fiducials. Images are captured of the checkerboard with the LEDs on and off in rapid succession. The difference of the two images automatically highlights the location of the four extreme corners, and these corner locations take the place of the manual selections. With this modification to the calibration routine, upwards of eighty mouse clicks are eliminated per stereo calibration. Preliminary test results indicate that accuracy is not substantially affected by the modified procedure. Improved automation to camera calibration procedures may finally penetrate the barriers to the use of calibration in practice.

  20. Detecting payload performance based on relative radiometric characteristic: case of the optical sensors

    Science.gov (United States)

    Han, Jie; Li, Shengyang; Zhang, Tao; Qin, Bangyong

    2016-10-01

    In this paper, we propose a novel algorithm for accurately estimating the degree of radiometric non-uniformity in remote sensing images. The algorithm was tested on high-quality images and heavily striping images, and quantitative analyses were conducted to evaluate the performance for each band by measuring the radiometric non-uniformity of the images. The results demonstrated that the proposed algorithm exhibits high accuracy and stability compared with traditional algorithms. The radiometric performance of TianGong-1 short-wave infrared images was calculated using this new method, and it was highly correlated with the solar angle, pitch angle and refrigerator thermal according to the Apriori algorithm. Based on these results, we have proposed a strategy for restricting increases in striping.

  1. Radiometric calipers for borehole logging

    International Nuclear Information System (INIS)

    Charbucinski, J.; Wylie, A.W.; Jarrett, R.G.

    1976-01-01

    Two versions of a radiometric-type caliper for measuring borehole diameter are described. One, based on the bow-spring principle, is suitable for percussion (exploration) drill holes. The other, which utilizes hemispherical wall contactors actuated by springs, is suitable for blast holes. Both utilize low-power radioactive sources and employ a scintillation detector to measure the 'inverse-square law' response of the device to changes in borehole radius. The performance of the device is examined and examples of its use are illustrated. (author)

  2. User-calibration of Mettler AT200 analytical balance

    International Nuclear Information System (INIS)

    Estill, J.

    1996-01-01

    The purpose of this technical implementing procedure (TIP) is to describe the calibration of the Mettler AT200 analytical balance or similar type balance (henceforth called the balance). This balance is used for activities of the Scientific Investigation Plan (SIP) ''Metal Barrier Selection and Testing'' (SIP-CM-01, WBS nr. 1.2.2.5.1). In particular, it will be used for Activity E-20-50, ''Long-Term Corrosion Studies.'' The balance will be used for weighing test specimens and reagent chemicals. However, it is not limited to these uses. The calibration procedures consist of activating the internal (self) calibration of the apparatus, and weighing and recording of traceable standards. The balance is equipped with self (internal) calibration and linearization capabilities. It has an internal (built in) set of weights which are used for self calibration. The standard weights are traceable to National Institute of Standards and Technology (NIST)

  3. Development of an in situ calibration technique for combustible gas detectors

    Science.gov (United States)

    Shumar, J. W.; Wynveen, R. A.; Lance, N., Jr.; Lantz, J. B.

    1977-01-01

    This paper describes the development of an in situ calibration procedure for combustible gas detectors (CGD). The CGD will be a necessary device for future space vehicles as many subsystems in the Environmental Control/Life Support System utilize or produce hydrogen (H2) gas. Existing calibration techniques are time-consuming and require support equipment such as an environmental chamber and calibration gas supply. The in situ calibration procedure involves utilization of a water vapor electrolysis cell for the automatic in situ generation of a H2/air calibration mixture within the flame arrestor of the CGD. The development effort concluded with the successful demonstration of in situ span calibrations of a CGD.

  4. Analysis of the radiometric survey during the Argonauta reactor operation

    International Nuclear Information System (INIS)

    Oliveira, Eara de S.L.; Cardozo, Katia K.M.; Silva, Joao Carlos P.; Santos, Joao Regis dos

    2013-01-01

    The Argonaut reactor at the Institute of Nuclear Engineering-IEN/CNEN, operates normally, the powers between 1.7 and 340 W on neutrongraphy procedures, production of radionuclides and experimental reactor physics lessons to postgraduate courses. The doses from neutrons and gamma radiation are measured when the reactor is critical, inside the reactor hall and surrounding regions. A study of the data obtained was performed to evaluate the daily need of this survey in the reactor hall. Taking into account the principle ALARA, which aims to optimize and minimize the dose received by the individual, we propose, in this work, through an analysis of the acquired data in occupational radiometric surveys, a reformulation of the area monitoring routine practiced by the team of radiological protection of the Institute of Nuclear Engineering - IEN/CNEN-RJ, whereas other monitoring routines regarding the radiological protection are also applied in the routine of the reactor. The operations under review occurred with the reactor operating 340 W power at intervals of 60, 120 and 180 minutes, in monitoring points in controlled areas, supervised and free. The results showed significant dose values in the output of the J-Channel 9 when the operation occurs with this open. With 180 minutes of operation, the measured values of dose rate were lower than the values at 60 min and 120 operations min. At the point in the supervised area, offsite to the reactor hall, situated in the direction of the J-Channel 9, the value reduces more than 14% in any operating time in relation to the dose rate measured at the point opposite the canal. There is a 50% reduction in the dose rates for operations with and J-9 closed. The results suggest a new frequency of radiometric survey whose mode of operation is maintained in similar conditions, since combined with other relevant practices of radiation protection

  5. Method of calibration for portable detectors of ionizing radiation

    International Nuclear Information System (INIS)

    Leal, Carlos; Carrizales, Lila; Guacaran, Douglas; Moreno, Ailed; Duran, Jose

    2008-01-01

    Full text: The LSCD is beginning a process of accreditation by the national authority of Venezuela (CENCAMER), so we felt the need to modify existing protocols calibration, suggested by the IAEA (Technical Reports Series No 133) to be adjusted in accordance with international standards of ISO 17025 EA-4/02 and Mexican standard NOM-021-NUCL-2002, adapting the calibration procedure of portable radiation detectors to those standards. The procedure used in the LSCD, conducts an intercomparison between measures between the standard reference and to calibrate the instrument, thus verifying the correct operation of the equipment and its usefulness to the individual or environmental radiation monitoring, not to exceed the limits primary for the public and occupationally Staff Exposed (POE), and propose a simple way to perform this calibration procedure and comply with the standard international and national standards, ensuring the proper functioning of the instruments calibrated. One of the calculations that has proven to be a useful tool in the verification of the conditions of operating the same, it is uncertainty, this procedure allows to characterize the response of individual detector, depending on the constraints specified by the manufacturer, to optimize the calibration is necessary to consider the multiple factors that can affect the measure and evaluate the response of the same, so it is vitally important estimating the typical uncertainty associated with the calibration technique employed, but this calculation is not trivial, depends on the type of detector found usually between 5% to 20%, both in uncertainty as the linearity, which are the parameters that are set to consider an instrument in good or bad condition. Typical are calibrated are: monitors air Geiger-Muller, Ionization cameras, detector of Neutron's, Proportional Counter, Personal dosimeters. (author)

  6. Radiometric microbiologic assay for the biologically active forms of niacin

    Energy Technology Data Exchange (ETDEWEB)

    Kertcher, J.A.; Guilarte, T.R.; Chen, M.F.; Rider, A.A.; McIntyre, P.A.

    1979-05-01

    A radiometric microbiologic assay has been developed for the determination of niacin in biologic fluids. Lactobacillus plantarum produced /sup 14/CO/sub 2/ from L-(U-/sup 14/C) malic acid in quantities proportional to the amount of niacin present. The assay is specific for the biologically active forms of niacin in humans. Thirty normal hemolysates were analyzed and the values ranged from 13.0 to 17.8 ..mu..g niacin/ml RBC (mean = 15.27 +- 1.33 s.d.). Good recovery and reproducibility studies were obtained with this assay. On thirty blood samples, correlation was excellent between the radiometric and the conventional turbidimetric assays.

  7. Chaos, Consternation and CALIPSO Calibration: New Strategies for Calibrating the CALIOP 1064 nm Channel

    Science.gov (United States)

    Vaughan, Mark; Garnier, Anne; Liu, Zhaoyan; Josset, Damien; Hu, Yongxiang; Lee, Kam-Pui; Hunt, William; Vernier, Jean-Paul; Rodier, Sharon; Pelon, Jaques; hide

    2012-01-01

    The very low signal-to-noise ratios of the 1064 nm CALIOP molecular backscatter signal make it effectively impossible to employ the "clear air" normalization technique typically used to calibrate elastic back-scatter lidars. The CALIPSO mission has thus chosen to cross-calibrate their 1064 nm measurements with respect to the 532 nm data using the two-wavelength backscatter from cirrus clouds. In this paper we discuss several known issues in the version 3 CALIOP 1064 nm calibration procedure, and describe the strategies that will be employed in the version 4 data release to surmount these problems.

  8. Multi-Sensor Calibration of Low-Cost Magnetic, Angular Rate and Gravity Systems

    Directory of Open Access Journals (Sweden)

    Markus Lüken

    2015-10-01

    Full Text Available We present a new calibration procedure for low-cost nine degrees-of-freedom (9DOF magnetic, angular rate and gravity (MARG sensor systems, which relies on a calibration cube, a reference table and a body sensor network (BSN. The 9DOF MARG sensor is part of our recently-developed “Integrated Posture and Activity Network by Medit Aachen” (IPANEMA BSN. The advantage of this new approach is the use of the calibration cube, which allows for easy integration of two sensor nodes of the IPANEMA BSN. One 9DOF MARG sensor node is thereby used for calibration; the second 9DOF MARG sensor node is used for reference measurements. A novel algorithm uses these measurements to further improve the performance of the calibration procedure by processing arbitrarily-executed motions. In addition, the calibration routine can be used in an alignment procedure to minimize errors in the orientation between the 9DOF MARG sensor system and a motion capture inertial reference system. A two-stage experimental study is conducted to underline the performance of our calibration procedure. In both stages of the proposed calibration procedure, the BSN data, as well as reference tracking data are recorded. In the first stage, the mean values of all sensor outputs are determined as the absolute measurement offset to minimize integration errors in the derived movement model of the corresponding body segment. The second stage deals with the dynamic characteristics of the measurement system where the dynamic deviation of the sensor output compared to a reference system is Sensors 2015, 15 25920 corrected. In practical validation experiments, this procedure showed promising results with a maximum RMS error of 3.89°.

  9. Multi-sensor calibration of low-cost magnetic, angular rate and gravity systems.

    Science.gov (United States)

    Lüken, Markus; Misgeld, Berno J E; Rüschen, Daniel; Leonhardt, Steffen

    2015-10-13

    We present a new calibration procedure for low-cost nine degrees-of-freedom (9DOF) magnetic, angular rate and gravity (MARG) sensor systems, which relies on a calibration cube, a reference table and a body sensor network (BSN). The 9DOF MARG sensor is part of our recently-developed "Integrated Posture and Activity Network by Medit Aachen" (IPANEMA) BSN. The advantage of this new approach is the use of the calibration cube, which allows for easy integration of two sensor nodes of the IPANEMA BSN. One 9DOF MARG sensor node is thereby used for calibration; the second 9DOF MARG sensor node is used for reference measurements. A novel algorithm uses these measurements to further improve the performance of the calibration procedure by processing arbitrarily-executed motions. In addition, the calibration routine can be used in an alignment procedure to minimize errors in the orientation between the 9DOF MARG sensor system and a motion capture inertial reference system. A two-stage experimental study is conducted to underline the performance of our calibration procedure. In both stages of the proposed calibration procedure, the BSN data, as well as reference tracking data are recorded. In the first stage, the mean values of all sensor outputs are determined as the absolute measurement offset to minimize integration errors in the derived movement model of the corresponding body segment. The second stage deals with the dynamic characteristics of the measurement system where the dynamic deviation of the sensor output compared to a reference system is Sensors 2015, 15 25920 corrected. In practical validation experiments, this procedure showed promising results with a maximum RMS error of 3.89°.

  10. Vibration transducer calibration techniques

    Science.gov (United States)

    Brinkley, D. J.

    1980-09-01

    Techniques for the calibration of vibration transducers used in the Aeronautical Quality Assurance Directorate of the British Ministry of Defence are presented. Following a review of the types of measurements necessary in the calibration of vibration transducers, the performance requirements of vibration transducers, which can be used to measure acceleration, velocity or vibration amplitude, are discussed, with particular attention given to the piezoelectric accelerometer. Techniques for the accurate measurement of sinusoidal vibration amplitude in reference-grade transducers are then considered, including the use of a position sensitive photocell and the use of a Michelson laser interferometer. Means of comparing the output of working-grade accelerometers with that of previously calibrated reference-grade devices are then outlined, with attention given to a method employing a capacitance bridge technique and a method to be used at temperatures between -50 and 200 C. Automatic calibration procedures developed to speed up the calibration process are outlined, and future possible extensions of system software are indicated.

  11. Calibration of areal surface topography measuring instruments

    Science.gov (United States)

    Seewig, J.; Eifler, M.

    2017-06-01

    The ISO standards which are related to the calibration of areal surface topography measuring instruments are the ISO 25178-6xx series which defines the relevant metrological characteristics for the calibration of different measuring principles and the ISO 25178-7xx series which defines the actual calibration procedures. As the field of areal measurement is however not yet fully standardized, there are still open questions to be addressed which are subject to current research. Based on this, selected research results of the authors in this area are presented. This includes the design and fabrication of areal material measures. For this topic, two examples are presented with the direct laser writing of a stepless material measure for the calibration of the height axis which is based on the Abbott- Curve and the manufacturing of a Siemens star for the determination of the lateral resolution limit. Based on these results, as well a new definition for the resolution criterion, the small scale fidelity, which is still under discussion, is presented. Additionally, a software solution for automated calibration procedures is outlined.

  12. ANALYSIS OF THE RADIOMETRIC RESPONSE OF ORANGE TREE CROWN IN HYPERSPECTRAL UAV IMAGES

    Directory of Open Access Journals (Sweden)

    N. N. Imai

    2017-10-01

    Full Text Available High spatial resolution remote sensing images acquired by drones are highly relevant data source in many applications. However, strong variations of radiometric values are difficult to correct in hyperspectral images. Honkavaara et al. (2013 presented a radiometric block adjustment method in which hyperspectral images taken from remotely piloted aerial systems – RPAS were processed both geometrically and radiometrically to produce a georeferenced mosaic in which the standard Reflectance Factor for the nadir is represented. The plants crowns in permanent cultivation show complex variations since the density of shadows and the irradiance of the surface vary due to the geometry of illumination and the geometry of the arrangement of branches and leaves. An evaluation of the radiometric quality of the mosaic of an orange plantation produced using images captured by a hyperspectral imager based on a tunable Fabry-Pérot interferometer and applying the radiometric block adjustment method, was performed. A high-resolution UAV based hyperspectral survey was carried out in an orange-producing farm located in Santa Cruz do Rio Pardo, state of São Paulo, Brazil. A set of 25 narrow spectral bands with 2.5 cm of GSD images were acquired. Trend analysis was applied to the values of a sample of transects extracted from plants appearing in the mosaic. The results of these trend analysis on the pixels distributed along transects on orange tree crown showed the reflectance factor presented a slightly trend, but the coefficients of the polynomials are very small, so the quality of mosaic is good enough for many applications.

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

    International Nuclear Information System (INIS)

    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

  14. METHOD OF RADIOMETRIC DISTORTION CORRECTION OF MULTISPECTRAL DATA FOR THE EARTH REMOTE SENSING

    Directory of Open Access Journals (Sweden)

    A. N. Grigoriev

    2015-07-01

    Full Text Available The paper deals with technologies of ground secondary processing of heterogeneous multispectral data. The factors of heterogeneous data include uneven illumination of objects on the Earth surface caused by different properties of the relief. A procedure for the image restoration of spectral channels by means of terrain distortion compensation is developed. The object matter of this paper is to improve the quality of the results during image restoration of areas with large and medium landforms. Methods. Researches are based on the elements of the digital image processing theory, statistical processing of the observation results and the theory of multi-dimensional arrays. Main Results. The author has introduced operations on multidimensional arrays: concatenation and elementwise division. Extended model description for input data about the area is given. The model contains all necessary data for image restoration. Correction method for multispectral data radiometric distortions of the Earth remote sensing has been developed. The method consists of two phases: construction of empirical dependences for spectral reflectance on the relief properties and restoration of spectral images according to semiempirical data. Practical Relevance. Research novelty lies in developme nt of the application theory of multidimensional arrays with respect to the processing of multispectral data, together with data on the topography and terrain objects. The results are usable for development of radiometric data correction tools. Processing is performed on the basis of a digital terrain model without carrying out ground works connected with research of the objects reflective properties.

  15. A Room-Temperature Pre-calibration Procedure for Gradiometer Sifting

    International Nuclear Information System (INIS)

    Zhang Shu-Lin; Liu Yang-Bo; Wang Yong-Liang; Kong Xiang-Yan; Xie Xiao-Ming; Liu Ming

    2011-01-01

    In order to detect extremely weak magnetic signals, superconducting quantum interference device (SQUID) gradiometers are widely used to suppress environmental noise. A hardware SQUID gradiometer consists of a niobium gradio-antenna and an SQUID, which are coupled via an input coil. Here gradiometer imbalance may greatly reduce its noise suppression performance. The gradiometer balance depends on the geometrical forms of the antenna wound by niobium wire. We describe a simple method based on Faraday's law for the pre-calibration of the gradiometer balance at room temperature, before the gradiometer is set up. The pre-calibrating results are compared with the measured balance of an SQUID gradiometer system. This method may be used for sifting hardware gradiometers for multi-channel systems. (cross-disciplinary physics and related areas of science and technology)

  16. Calibration issues of the TFTR multichannel neutron collimator

    International Nuclear Information System (INIS)

    Goeler, S. von; Johnson, L.C.; Bitter, M.; Efthimion, P.C.; Roquemore, A.L.

    1996-01-01

    The calibration procedures for the detectors in the Neutron Collimator are reviewed. The absolute calibration was performed for the NE451 detectors, in situ, by moving a DT neutron generator in the TFTR vacuum vessel across each sight line. This calibration was transferred to other detectors in the same channel. Four new sight lines have been installed at a different toroidal location, which view the plasma through the vacuum vessel port cover rather than through thinned windows. The new detectors are cross-calibrated to the NE451 detectors with a jog shot procedure, where the plasma is quickly shifted in major radius over a distance of 30 cm. The jog shot procedure shows that scattered neutrons account approximately for 30% of the signal of the new central channels. The neutron source strength from the collimator agrees within 10% with the source strength from global neutron monitors in the TFTR test cell. Detector non-linearity is discussed. Another special issue is the behavior of the detectors during T-puffs, where the DD/DT neutron ratio changes rapidly

  17. Optical Imaging and Radiometric Modeling and Simulation

    Science.gov (United States)

    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

  18. Cuban-Brazilian comparison of the calibration procedures for surface contamination monitors

    International Nuclear Information System (INIS)

    Salas, Gonzalo W.; Garcia, Jose A.T.; Ramos, Manoel M.O.

    2007-01-01

    The calibration laboratory of the CPHR, Centro de Proteccion e Higiene de las Radiaciones, is the only laboratory that performs calibrations of radiation protection instruments in Cuba. Recently they started a cooperation project with IAEA, code number CUB3002-01 with the task title 'Assuring and Demonstrating the safety of radioactive Waste Management'. Within the frame of this project they have a compromise to implement the calibration service for surface contamination monitors, for which they received instruments and sources. In 2006 the Laboratorio Nacional de Metrologia das Radiacoes Ionizantes (LNMRI) from the Instituto de Radioprotecao e Dosimetria, IRD/CNEN, was invited to perform a mission to CPHR in order to evaluate the level of implementation of the service trough the insertion of the service in the Quality Assurance System of their laboratory, and perform a comparison exercise to test the calibration method implemented. The results were evaluated by the methodology recommended in the ISO/IEC 43-1 standard. These results show that all values from both laboratories are comparable for most radionuclides except for Cl-36. The preliminary investigation about this situation is presented in the paper. (author)

  19. 40 CFR 92.122 - Smoke meter calibration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Smoke meter calibration. 92.122 Section 92.122 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... meter calibration. The smokemeter shall be checked according to the following procedure prior to each...

  20. Radiometric flow injection analysis with an ASIA (Ismatec) analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Myint, U; Win, N; San, K; Han, B; Myoe, K M [Yangon Univ. (Myanmar). Dept. of Chemistry; Toelgyessy, J [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Environmental Science

    1994-07-01

    Radiometric Flow Injection Analysis of a radioactive ([sup 131]I) sample is described. For analysis an ASIA (Ismatec) analyzer with a NaI(Tl) scintillation detector was used. (author) 5 refs.; 3 figs.

  1. Effects of line fiducial parameters and beamforming on ultrasound calibration.

    Science.gov (United States)

    Ameri, Golafsoun; Baxter, John S H; McLeod, A Jonathan; Peters, Terry M; Chen, Elvis C S

    2017-01-01

    Ultrasound (US)-guided interventions are often enhanced via integration with an augmented reality environment, a necessary component of which is US calibration. Calibration requires the segmentation of fiducials, i.e., a phantom, in US images. Fiducial localization error (FLE) can decrease US calibration accuracy, which fundamentally affects the total accuracy of the interventional guidance system. Here, we investigate the effects of US image reconstruction techniques as well as phantom material and geometry on US calibration. It was shown that the FLE was reduced by 29% with synthetic transmit aperture imaging compared with conventional B-mode imaging in a Z-bar calibration, resulting in a 10% reduction of calibration error. In addition, an evaluation of a variety of calibration phantoms with different geometrical and material properties was performed. The phantoms included braided wire, plastic straws, and polyvinyl alcohol cryogel tubes with different diameters. It was shown that these properties have a significant effect on calibration error, which is a variable based on US beamforming techniques. These results would have important implications for calibration procedures and their feasibility in the context of image-guided procedures.

  2. Calibrating a tensor magnetic gradiometer using spin data

    Science.gov (United States)

    Bracken, Robert E.; Smith, David V.; Brown, Philip J.

    2005-01-01

    Scalar magnetic data are often acquired to discern characteristics of geologic source materials and buried objects. It is evident that a great deal can be done with scalar data, but there are significant advantages to direct measurement of the magnetic gradient tensor in applications with nearby sources, such as unexploded ordnance (UXO). To explore these advantages, we adapted a prototype tensor magnetic gradiometer system (TMGS) and successfully implemented a data-reduction procedure. One of several critical reduction issues is the precise determination of a large group of calibration coefficients for the sensors and sensor array. To resolve these coefficients, we devised a spin calibration method, after similar methods of calibrating space-based magnetometers (Snare, 2001). The spin calibration procedure consists of three parts: (1) collecting data by slowly revolving the sensor array in the Earth?s magnetic field, (2) deriving a comprehensive set of coefficients from the spin data, and (3) applying the coefficients to the survey data. To show that the TMGS functions as a tensor gradiometer, we conducted an experimental survey that verified that the reduction procedure was effective (Bracken and Brown, in press). Therefore, because it was an integral part of the reduction, it can be concluded that the spin calibration was correctly formulated with acceptably small errors.

  3. Improved detection of Mycobacterium avium complex with the Bactec radiometric system

    International Nuclear Information System (INIS)

    Hoffner, S.E.

    1988-01-01

    A reconsideration of the laboratory methods used for primary isolation of mycobacteria other than Mycobacterium tuberculosis is needed due to the increasingly recognized importance of such mycobacterial infections in immunocompromised patients. One example of this is the severe opportunistic infections caused by Mycobacterium avium complex among AIDS patients. In this study, the Bactec radiometric system was compared to conventional culture on solid medium for the detection of M. avium complex in 3,612 selected clinical specimens, mainly of extrapulmonary origin. Of a total number of 63 M. avium complex isolates, the Bactec system detected 58 (92%), compared to 37 (59%) for conventional culture. A much more rapid detection was attained with radiometric technique than with conventional culture. The mean detection time for the cultures positive with both methods was 7.1 and 28.3 days, respectively. The Bactec radiometric system achieves a rapid and significantly more sensitive detection and seems to be an excellent complement to conventional culture in the laboratory diagnosis of infections with the M. avium complex

  4. Analysis of direct to diffuse partitioning of global solar irradiance at the radiometric station in Badajoz (Spain)

    Science.gov (United States)

    Sanchez, G.; Cancillo, M. L.; Serrano, A.

    2010-09-01

    This study is aimed at the analysis of the partitioning of global solar irradiance into its direct and diffuse components at the radiometric station in Badajoz (Spain). The detailed knowledge of the solar radiation field is of increasing interest in Southern Europe due to its use as renewable energy. In particular, the knowledge of the solar radiation partitioning into direct and diffuse radiation has become a major demand for the design and suitable orientation of solar panels in solar power plants. In this study the first measurements of solar diffuse irradiance performed in the radiometric station in Badajoz (Spain) are presented and analyzed in the framework of the partitioning of solar global radiation. Thus, solar global and diffuse irradiance were measured at one-minute basis from 23 November 2009 to 31 March 2010. Solar irradiances were measured by two Kipp&Zonen CMP11 pyranometers, using a Kipp&Zonen CM121 shadow ring for the measurements of solar diffuse irradiance. Diffuse measurements were corrected from the solid angle hidden by the ring and direct irradiance was calculated as the difference between global and diffuse measurements. Irradiance was obtained from the pyranomenters by applying calibration coefficients obtained in an inter-comparison campaign performed at INTA/El Arenosillo, in Huelva (Spain), last September 2009. There, calibration coefficients were calculated using as a reference a CMP11 pyranometer which had been previously calibrated by the Physikalisch-Meteorologisches Observatorium Davos/World Radiation Centre in Switzerland. In order to study the partitioning of the solar radiation, the global and diffuse irradiances have been analyzed for three typical different sky conditions: cloud-free, broken clouds and overcast. Particular days within the period of study have been selected by visual inspection. Along with the analysis of the global and diffuse irradiances themselves, ratios of these irradiances to the downward irradiance at the

  5. Calibration of hydrometers

    Science.gov (United States)

    Lorefice, Salvatore; Malengo, Andrea

    2006-10-01

    After a brief description of the different methods employed in periodic calibration of hydrometers used in most cases to measure the density of liquids in the range between 500 kg m-3 and 2000 kg m-3, particular emphasis is given to the multipoint procedure based on hydrostatic weighing, known as well as Cuckow's method. The features of the calibration apparatus and the procedure used at the INRiM (formerly IMGC-CNR) density laboratory have been considered to assess all relevant contributions involved in the calibration of different kinds of hydrometers. The uncertainty is strongly dependent on the kind of hydrometer; in particular, the results highlight the importance of the density of the reference buoyant liquid, the temperature of calibration and the skill of operator in the reading of the scale in the whole assessment of the uncertainty. It is also interesting to realize that for high-resolution hydrometers (division of 0.1 kg m-3), the uncertainty contribution of the density of the reference liquid is the main source of the total uncertainty, but its importance falls under about 50% for hydrometers with a division of 0.5 kg m-3 and becomes somewhat negligible for hydrometers with a division of 1 kg m-3, for which the reading uncertainty is the predominant part of the total uncertainty. At present the best INRiM result is obtained with commercially available hydrometers having a scale division of 0.1 kg m-3, for which the relative uncertainty is about 12 × 10-6.

  6. Prelaunch calibrations and on-orbit performance analysis of FY-2D SVISSR infrared channels

    Science.gov (United States)

    Zhang, Yong; Chen, Fuchun

    2014-10-01

    Meteorological satellites have become an irreplaceable weather and ocean-observing tool in China. These satellites are used to monitor natural disasters and improve the efficiency of many sectors of Chinese national economy. FY-2 series satellites are one of the key components of Chinese meteorological observing system and application system. In this paper, the operational satellite- FY-2D's infrared channels were focused and analyzed. The instruments' background was introduced briefly. The main payload SVISSR specifications were compared with its ancestral VISSR. The optical structure of the SVISSR was also expressed. FY-2D prelaunch calibrations methodology was introduced and the accuracies of the absolute radiometric calibration were analyzed. Some key optics on-orbit performance of FY-2D SVISSR were analyzed include onboard blackbody, cold FPA and detector noise level. All of these works show that FY- 2D's main payload SVISSR was in a healthy status.

  7. Radioactivity measurement of 18F in 16 ml vials for calibration of radionuclide calibrators

    International Nuclear Information System (INIS)

    Wurdiyanto, Gatot; Marsoem, Pujadi; Candra, Hermawan; Wijono, Paidi

    2012-01-01

    Fluorine-18 is obtained through the reaction 18 O(p, n) 18 F using a cyclotron that is situated in a hospital in Jakarta. Standardization of the 18 F solution is performed by gamma spectrometry using calibration sources of 152 Eu, 60 Co and 137 Cs that have traceability to the International System of units (SI). The activities in the 16 ml vials that were used for calibrating the radionuclide calibrators were between 1 and 2 GBq, with expanded uncertainties of 3.8%. The expanded uncertainty, at a coverage factor of k=2, on the derived calibration factor for the radionuclide calibrator was 6.6%. - Highlights: ► PTKMR–BATAN as a NMI of Indonesia is required to have procedures to calibrate the radionuclide calibrators. ► Standardizations were carried out on a solution of [ 18 F]FDG using gamma spectrometry. ► The volume of 18 F solutions used was 16 ml because this is the volume often used in hospitals. ► The Secondary Standard ionization chamber is a CRC-7BT Capintec radionuclide calibrator. ► A dial setting for 16 ml of [ 18 F]FDG solution in a vial is 443 for the Capintec dose calibrator.

  8. Application and sensitivity investigation of Fourier transforms for microwave radiometric inversions

    Science.gov (United States)

    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.

  9. Microsomal aryl hydrocarbon hydroxylase comparison of the direct, indirect and radiometric assays

    International Nuclear Information System (INIS)

    Denison, M.S.; Murray, M.; Wilkinson, C.F.

    1983-01-01

    The direct fluorometric assay of aryl hydrocarbon hydroxlyase has been compared to the more commonly used indirect fluorometric and radiometric assays. Although rat hepatic microsomal activities measured by the direct assay were consistently higher than those obtained by the other assays, the relative changes in activity following enzyme induction and/or inhibition were similar. The direct assay provides an accurate and rapid measure of aryl hydrocarbon hydroxylase activity and avoids several problems inherent in the indirect and radiometric assays. 2 tables

  10. Reliability-Based Code Calibration

    DEFF Research Database (Denmark)

    Faber, M.H.; Sørensen, John Dalsgaard

    2003-01-01

    The present paper addresses fundamental concepts of reliability based code calibration. First basic principles of structural reliability theory are introduced and it is shown how the results of FORM based reliability analysis may be related to partial safety factors and characteristic values....... Thereafter the code calibration problem is presented in its principal decision theoretical form and it is discussed how acceptable levels of failure probability (or target reliabilities) may be established. Furthermore suggested values for acceptable annual failure probabilities are given for ultimate...... and serviceability limit states. Finally the paper describes the Joint Committee on Structural Safety (JCSS) recommended procedure - CodeCal - for the practical implementation of reliability based code calibration of LRFD based design codes....

  11. Rapid radiometric method for detection of Salmonella in foods

    International Nuclear Information System (INIS)

    Stewart, B.J.; Eyles, M.J.; Murrell, W.G.

    1980-01-01

    A radiometric method for the detection of Salmonella in foods has been developed which is based on Salmonella poly H agglutinating serum preventing Salmonella from producing 14CO2 from [14C] dulcitol. The method will detect the presence or absence of Salmonella in a product within 30 h compared to 4 to 5 days by routine culture methods. The method has been evaluated against a routine culture method using 58 samples of food. The overall agreement was 91%. Five samples negative for Salmonella by the routine method were positive by the radiometric method. These may have been false positives. However, the routine method may have failed to detect Salmonella due to the presence of large numbers of lactose-fermenting bacteria which hindered isolation of Salmonella colonies on the selective agar plates

  12. Calibration Methods for Reliability-Based Design Codes

    DEFF Research Database (Denmark)

    Gayton, N.; Mohamed, A.; Sørensen, John Dalsgaard

    2004-01-01

    The calibration methods are applied to define the optimal code format according to some target safety levels. The calibration procedure can be seen as a specific optimization process where the control variables are the partial factors of the code. Different methods are available in the literature...

  13. Validating and comparing GNSS antenna calibrations

    Science.gov (United States)

    Kallio, Ulla; Koivula, Hannu; Lahtinen, Sonja; Nikkonen, Ville; Poutanen, Markku

    2018-03-01

    GNSS antennas have no fixed electrical reference point. The variation of the phase centre is modelled and tabulated in antenna calibration tables, which include the offset vector (PCO) and phase centre variation (PCV) for each frequency according to the elevations and azimuths of the incoming signal. Used together, PCV and PCO reduce the phase observations to the antenna reference point. The remaining biases, called the residual offsets, can be revealed by circulating and rotating the antennas on pillars. The residual offsets are estimated as additional parameters when combining the daily GNSS network solutions with full covariance matrix. We present a procedure for validating the antenna calibration tables. The dedicated test field, called Revolver, was constructed at Metsähovi. We used the procedure to validate the calibration tables of 17 antennas. Tables from the IGS and three different calibration institutions were used. The tests show that we were able to separate the residual offsets at the millimetre level. We also investigated the influence of the calibration tables from the different institutions on site coordinates by performing kinematic double-difference baseline processing of the data from one site with different antenna tables. We found small but significant differences between the tables.

  14. Cross-calibration of Medium Resolution Earth Observing Satellites by Using EO-1 Hyperion-derived Spectral Surface Reflectance from "Lunar Cal Sites"

    Science.gov (United States)

    Ungar, S.

    2017-12-01

    Over the past 3 years, the Earth Observing-one (EO-1) Hyperion imaging spectrometer was used to slowly scan the lunar surface at a rate which results in up to 32X oversampling to effectively increase the SNR. Several strategies, including comparison against the USGS RObotic Lunar Observatory (ROLO) mode,l are being employed to estimate the absolute and relative accuracy of the measurement set. There is an existing need to resolve discrepancies as high as 10% between ROLO and solar based calibration of current NASA EOS assets. Although the EO-1 mission was decommissioned at the end of March 2017, the development of a well-characterized exoatmospheric spectral radiometric database, for a range of lunar phase angles surrounding the fully illuminated moon, continues. Initial studies include a comprehensive analysis of the existing 17-year collection of more than 200 monthly lunar acquisitions. Specific lunar surface areas, such as a lunar mare, are being characterized as potential "lunar calibration sites" in terms of their radiometric stability in the presence of lunar nutation and libration. Site specific Hyperion-derived lunar spectral reflectance are being compared against spectrographic measurements made during the Apollo program. Techniques developed through this activity can be employed by future high-quality orbiting imaging spectrometers (such as HyspIRI and EnMap) to further refine calibration accuracies. These techniques will enable the consistent cross calibration of existing and future earth observing systems (spectral and multi-spectral) including those that do not have lunar viewing capability. When direct lunar viewing is not an option for an earth observing asset, orbiting imaging spectrometers can serve as transfer radiometers relating that asset's sensor response to lunar values through near contemporaneous observations of well characterized stable CEOS test sites. Analysis of this dataset will lead to the development of strategies to ensure more

  15. Radiometric Normalization of Temporal Images Combining Automatic Detection of Pseudo-Invariant Features from the Distance and Similarity Spectral Measures, Density Scatterplot Analysis, and Robust Regression

    Directory of Open Access Journals (Sweden)

    Ana Paula Ferreira de Carvalho

    2013-05-01

    Full Text Available Radiometric precision is difficult to maintain in orbital images due to several factors (atmospheric conditions, Earth-sun distance, detector calibration, illumination, and viewing angles. These unwanted effects must be removed for radiometric consistency among temporal images, leaving only land-leaving radiances, for optimum change detection. A variety of relative radiometric correction techniques were developed for the correction or rectification of images, of the same area, through use of reference targets whose reflectance do not change significantly with time, i.e., pseudo-invariant features (PIFs. This paper proposes a new technique for radiometric normalization, which uses three sequential methods for an accurate PIFs selection: spectral measures of temporal data (spectral distance and similarity, density scatter plot analysis (ridge method, and robust regression. The spectral measures used are the spectral angle (Spectral Angle Mapper, SAM, spectral correlation (Spectral Correlation Mapper, SCM, and Euclidean distance. The spectral measures between the spectra at times t1 and t2 and are calculated for each pixel. After classification using threshold values, it is possible to define points with the same spectral behavior, including PIFs. The distance and similarity measures are complementary and can be calculated together. The ridge method uses a density plot generated from images acquired on different dates for the selection of PIFs. In a density plot, the invariant pixels, together, form a high-density ridge, while variant pixels (clouds and land cover changes are spread, having low density, facilitating its exclusion. Finally, the selected PIFs are subjected to a robust regression (M-estimate between pairs of temporal bands for the detection and elimination of outliers, and to obtain the optimal linear equation for a given set of target points. The robust regression is insensitive to outliers, i.e., observation that appears to deviate

  16. High speed radiometric measurements of IED detonation fireballs

    Science.gov (United States)

    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 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.

  17. EPMT: a portable transfer standard for telemetry system pressure-transducer calibration

    International Nuclear Information System (INIS)

    Hasbrouck, R.T.

    1977-01-01

    The LLL developed electronic pressure meter (EPMT) is a portable static-pressure calibration instrument for use with the LLL telemetry transducer system at the Nevada Test Site (NTS). It is significantly more accurate and rugged than the bourdon-tube pressure gauge it replaces, and can be incorporated into a field-use, semi-automatic, pressure calibration system. The process by which a transducer is selected for EPMT use from the inventory of field-service-certified transducers and subjected to an extensive preconditioning and calibration procedure is described. By combining this unusual calibration procedure with a unique, statistically based data-reduction routine, the total uncertainty of the measuring process at each calibration point can be determined with high accuracy

  18. Remote sensing, airborne radiometric survey and aeromagnetic survey data processing and analysis

    International Nuclear Information System (INIS)

    Dong Xiuzhen; Liu Dechang; Ye Fawang; Xuan Yanxiu

    2009-01-01

    Taking remote sensing data, airborne radiometric data and aero magnetic survey data as an example, the authors elaborate about basic thinking of remote sensing data processing methods, spectral feature analysis and adopted processing methods, also explore the remote sensing data combining with the processing of airborne radiometric survey and aero magnetic survey data, and analyze geological significance of processed image. It is not only useful for geological environment research and uranium prospecting in the study area, but also reference to applications in another area. (authors)

  19. Validation of calibration procedures for freeform parts on CMMs

    DEFF Research Database (Denmark)

    Savio, Enrico; De Chiffre, Leonardo

    2003-01-01

    The paper describes the validation of a new method for establishment of traceability of freeform measurements on coordinate measuring machines currently being considered for development as a new ISO standard. The method deals with calibration by: i) repeated measurements of a given uncalibrated...

  20. Atmospheric and Radiometric Correction Algorithms for the Multitemporal Assessment of Grasslands Productivity

    Directory of Open Access Journals (Sweden)

    Jesús A. Prieto-Amparan

    2018-02-01

    Full Text Available A key step in the processing of satellite imagery is the radiometric correction of images to account for reflectance that water vapor, atmospheric dust, and other atmospheric elements add to the images, causing imprecisions in variables of interest estimated at the earth’s surface level. That issue is important when performing spatiotemporal analyses to determine ecosystems’ productivity. In this study, three correction methods were applied to satellite images for the period 2010–2014. These methods were Atmospheric Correction for Flat Terrain 2 (ATCOR2, Fast Line-of-Sight Atmospheric Analysis of Spectral Hypercubes (FLAASH, and Dark Object Substract 1 (DOS1. The images included 12 sub-scenes from the Landsat Thematic Mapper (TM and the Operational Land Imager (OLI sensors. The images corresponded to three Permanent Monitoring Sites (PMS of grasslands, ‘Teseachi’, ‘Eden’, and ‘El Sitio’, located in the state of Chihuahua, Mexico. After the corrections were applied to the images, they were evaluated in terms of their precision for biomass estimation. For that, biomass production was measured during the study period at the three PMS to calibrate production models developed with simple and multiple linear regression (SLR and MLR techniques. When the estimations were made with MLR, DOS1 obtained an R2 of 0.97 (p < 0.05 for 2012 and values greater than 0.70 (p < 0.05 during 2013–2014. The rest of the algorithms did not show significant results and DOS1, which is the simplest algorithm, resulted in the best biomass estimator. Thus, in the multitemporal analysis of grassland based on spectral information, it is not necessary to apply complex correction procedures. The maps of biomass production, elaborated from images corrected with DOS1, can be used as a reference point for the assessment of the grassland condition, as well as to determine the grazing capacity and thus the potential animal production in such ecosystems.

  1. Evaluation of uncertainties in the calibration of radiation survey meter

    International Nuclear Information System (INIS)

    Potiens, M.P.A.; Santos, G.P.

    2006-01-01

    In order to meet the requirements of ISO 17025, the quantification of the expanded uncertainties of experimental data in the calibration of survey meters must be carried out using well defined concepts, like those expressed in the 'ISO-Guide to the Expression of Uncertainty in Measurement'. The calibration procedure of gamma ray survey meters involves two values that have to get their uncertainties clearly known: measurements of the instrument under calibration and the conventional true values of a quantity. Considering the continuous improvement of the calibration methods and set-ups, it is necessary to evaluate periodically the involved uncertainties in the procedures. In this work it is shown how the measurement uncertainties of an individual calibration can be estimated and how it can be generalized to be valid for others radiation survey meters. (authors)

  2. Calibration of radon-222 detectors using closed circuit radium-226 sources

    International Nuclear Information System (INIS)

    Perna, Allan Felipe Nunes; Paschuk, Sergei Anatolyevich; Correa, Janine Nicolosi; Del Claro, Flavia

    2012-01-01

    This paper presents the results of the calibration of the Radon-222 detectors used by the Laboratories specializing in measuring natural radiation from this gas. The research was conducted in collaboration between UTFPR, CDTN/CNEN, UFRN and IRD/CNEN. During the calibration the detectors were exposed in isolated chambers with radioactive calibrated sources. The calibration procedure was supported with four instant radon monitors AlphaGUARD (SAPHYMO Co.) responsible for radon activity measurements in the experimental chamber. The calibration procedure resulted an equation that relates the number of tracks found in solid-state detector CR-39 (Track-Etch detector) with the concentration of radon in the atmosphere. Obtained results are compatible with previously performed calibration at the National Institute of Radiological Sciences (NIRS, Japan) using high activity levels of radon in air. Present results of calibration give the possibility to expand the calibration curve of CR-39 for medium and low activity levels of radon. (author)

  3. A superconducting wavelength shifter as primary radiometric source standard in the X-ray range

    Energy Technology Data Exchange (ETDEWEB)

    Klein, R. [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany)], E-mail: roman.klein@ptb.de; Brandt, G.; Cibik, L.; Gerlach, M.; Krumrey, M.; Mueller, P.; Ulm, G. [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany); Scheer, M. [BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany)

    2007-10-11

    For more than 20 years, the Physikalisch-Technische Bundesanstalt (PTB) has been using the calculable radiation of bending magnets from the BESSY I and BESSY II electron storage rings in the visible, UV, vacuum-UV (VUV) and X-ray spectral range for radiometry, especially for the calibration of radiation sources and energy-dispersive detectors. Due to its-compared to bending magnets-higher magnetic field, wavelength shifters (WLS) have the potential to extend the usable spectral range for these applications to higher photon energies. Thus, the characteristic energies of BESSY II bending magnet radiation and a 6 T WLS radiation are 2.5 and 11.5 keV, respectively. Within the scope of this work, the properties of the synchrotron radiation from the 6 T WLS have been investigated and compared to theoretical predictions for photon energies up to 150 keV. Good agreement within the experimental uncertainty of several percent was found. Further improvements for a future radiometric use of WLS radiation with low uncertainties will be discussed.

  4. A superconducting wavelength shifter as primary radiometric source standard in the X-ray range

    International Nuclear Information System (INIS)

    Klein, R.; Brandt, G.; Cibik, L.; Gerlach, M.; Krumrey, M.; Mueller, P.; Ulm, G.; Scheer, M.

    2007-01-01

    For more than 20 years, the Physikalisch-Technische Bundesanstalt (PTB) has been using the calculable radiation of bending magnets from the BESSY I and BESSY II electron storage rings in the visible, UV, vacuum-UV (VUV) and X-ray spectral range for radiometry, especially for the calibration of radiation sources and energy-dispersive detectors. Due to its-compared to bending magnets-higher magnetic field, wavelength shifters (WLS) have the potential to extend the usable spectral range for these applications to higher photon energies. Thus, the characteristic energies of BESSY II bending magnet radiation and a 6 T WLS radiation are 2.5 and 11.5 keV, respectively. Within the scope of this work, the properties of the synchrotron radiation from the 6 T WLS have been investigated and compared to theoretical predictions for photon energies up to 150 keV. Good agreement within the experimental uncertainty of several percent was found. Further improvements for a future radiometric use of WLS radiation with low uncertainties will be discussed

  5. A superconducting wavelength shifter as primary radiometric source standard in the X-ray range

    Science.gov (United States)

    Klein, R.; Brandt, G.; Cibik, L.; Gerlach, M.; Krumrey, M.; Müller, P.; Ulm, G.; Scheer, M.

    2007-10-01

    For more than 20 years, the Physikalisch-Technische Bundesanstalt (PTB) has been using the calculable radiation of bending magnets from the BESSY I and BESSY II electron storage rings in the visible, UV, vacuum-UV (VUV) and X-ray spectral range for radiometry, especially for the calibration of radiation sources and energy-dispersive detectors. Due to its—compared to bending magnets—higher magnetic field, wavelength shifters (WLS) have the potential to extend the usable spectral range for these applications to higher photon energies. Thus, the characteristic energies of BESSY II bending magnet radiation and a 6 T WLS radiation are 2.5 and 11.5 keV, respectively. Within the scope of this work, the properties of the synchrotron radiation from the 6 T WLS have been investigated and compared to theoretical predictions for photon energies up to 150 keV. Good agreement within the experimental uncertainty of several percent was found. Further improvements for a future radiometric use of WLS radiation with low uncertainties will be discussed.

  6. The ENEA calibration service for ionising radiations

    International Nuclear Information System (INIS)

    Monteventi, F.; Sermenghi, I.

    1999-01-01

    The report describes all the facilities available at the the service of the ENEA Calibration Service for Ionising Radiations at Bologna (Italy). It gives a detailed description of all equipments qualified for photon fields metrology including the secondary standards and the calibration procedures performed for radiation monitoring devices and dosemeters [it

  7. Helicopter-borne magnetic, electromagnetic and radiometric geophysical survey at Vanna, Karlsoey

    International Nuclear Information System (INIS)

    Rodionov, Alexei; Ofstad, Frode

    2012-01-01

    NGU conducted an airborne geophysical survey in Vanna area in June 2011 as a part of MINN project. This report describes and documents the acquisition, processing and visualization of recorded datasets. The geophysical survey results reported herein are 1336 line km. The modified Geotech Ltd. Hummingbird frequency domain system supplemented by optically pumped cesium magnetometer and 1024 channels RSX-5 spectrometer was used for data acquisition. The survey was flown with 200 m line spacing, line direction of 27 degrees NW and average speed 106 km/h. The average terrain clearance of the bird was 59 m. Collected data were processed in NGU using Geosoft Oasis Montaj software. Raw total magnetic field data were corrected for diurnal variation and levelled using standard micro levelling algorithm. EM data were filtered and levelled using both -automated and manual levelling procedure. Apparent resistivity was calculated from in-phase and quadrature data for four frequencies separately using a homogeneous half space model. Apparent resistivity dataset was filtered and levelled. Radiometric data were processed using standard procedures recommended by International Atomic Energy Association. All data were gridded with the cell size of 50 m and presented as a shaded relief maps at the scale of 1:50 000. (Author)

  8. Helicopter-borne magnetic, electromagnetic and radiometric geophysical survey at Vanna, Karlsoey

    Energy Technology Data Exchange (ETDEWEB)

    Rodionov, Alexei; Ofstad, Frode

    2012-07-01

    NGU conducted an airborne geophysical survey in Vanna area in June 2011 as a part of MINN project. This report describes and documents the acquisition, processing and visualization of recorded datasets. The geophysical survey results reported herein are 1336 line km. The modified Geotech Ltd. Hummingbird frequency domain system supplemented by optically pumped cesium magnetometer and 1024 channels RSX-5 spectrometer was used for data acquisition. The survey was flown with 200 m line spacing, line direction of 27 degrees NW and average speed 106 km/h. The average terrain clearance of the bird was 59 m. Collected data were processed in NGU using Geosoft Oasis Montaj software. Raw total magnetic field data were corrected for diurnal variation and levelled using standard micro levelling algorithm. EM data were filtered and levelled using both -automated and manual levelling procedure. Apparent resistivity was calculated from in-phase and quadrature data for four frequencies separately using a homogeneous half space model. Apparent resistivity dataset was filtered and levelled. Radiometric data were processed using standard procedures recommended by International Atomic Energy Association. All data were gridded with the cell size of 50 m and presented as a shaded relief maps at the scale of 1:50 000. (Author)

  9. Paleomagnetic, paleontologic and radiometric study of the Uquia Formation (Plio-Pleistocene) in Esquina Blanca (Jujuy)

    International Nuclear Information System (INIS)

    Walther, Ana M.; Orgeira, Maria J.; Vilas, Juan F.A.; Kelley, Shari; Jordan, Teresa

    1998-01-01

    A multidisciplinary study of the Uquia Formation has been performed. The results of the paleontologic, paleomagnetic, radiometric and stratigraphic analyses suggest that the superior levels of the formation are equivalent to the 'Marplatense Superior', while the basic ones should be considered older. Radiometric ages have been determined by fission tracks in zircons

  10. Sensor Calibration Design Based on D-Optimality Criterion

    Directory of Open Access Journals (Sweden)

    Hajiyev Chingiz

    2016-09-01

    Full Text Available In this study, a procedure for optimal selection of measurement points using the D-optimality criterion to find the best calibration curves of measurement sensors is proposed. The coefficients of calibration curve are evaluated by applying the classical Least Squares Method (LSM. As an example, the problem of optimal selection for standard pressure setters when calibrating a differential pressure sensor is solved. The values obtained from the D-optimum measurement points for calibration of the differential pressure sensor are compared with those from actual experiments. Comparison of the calibration errors corresponding to the D-optimal, A-optimal and Equidistant calibration curves is done.

  11. Deep Space Network Radiometric Remote Sensing Program

    Science.gov (United States)

    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

  12. Calibration of reference KAP-meters at SSDL and cross calibration of clinical KAP-meters

    International Nuclear Information System (INIS)

    Hetland, Per O.; Friberg, Eva G.; Oevreboe, Kirsti M.; Bjerke, Hans H.

    2009-01-01

    In the summer of 2007 the secondary standard dosimetry laboratory (SSDL) in Norway established a calibration service for reference air-kerma product meter (KAP-meter). The air-kerma area product, PKA, is a dosimetric quantity that can be directly related to the patient dose and used for risk assessment associated with different x-ray examinations. The calibration of reference KAP-meters at the SSDL gives important information on parameters influencing the calibration factor for different types of KAP-meters. The use of reference KAP-meters calibrated at the SSDL is an easy and reliable way to calibrate or verify the PKA indicated by the x-ray equipment out in the clinics. Material and methods. Twelve KAP-meters were calibrated at the SSDL by use of the substitution method at five diagnostic radiation qualities (RQRs). Results. The calibration factors varied from 0.94 to 1.18. The energy response of the individual KAP-meters varied by a total of 20% between the different RQRs and the typical chamber transmission factors ranged from 0.78 to 0.91. Discussion. It is important to use a calibrated reference KAP-meter and a harmonised calibration method in the PKA calibration in hospitals. The obtained uncertainty in the PKA readings is comparable with other calibration methods if the information in the calibration certificate is correct used, corrections are made and proper positioning of the KAP-chamber is performed. This will ensure a reliable estimate of the patient dose and a proper optimisation of conventional x-ray examinations and interventional procedures

  13. Calibration of the indicators of the product KERMa-AREA in radiodiagnostic equipment

    International Nuclear Information System (INIS)

    Ginjaume, M.; Jarvinen, H.; Turak, O.

    2013-01-01

    Currently the IAEA proposes two procedures for the calibration of the determination of the PKA systems integrated in the x-ray equipment. The traditional method is to measure air kerma at a certain distance from the focus through an ionization chamber reference and then the area of the field of radiation in that position. The alternative method is based on measuring directly the product kerma-area using equipment calibrated in this magnitude. In both cases the calibration procedure takes into account the position of the tube on the stretcher of the patient. The objective of this study was to compare the practical application of both calibration procedures as well as assess the accuracy of indication of the PKA in the consoles of the radiology equipment. (Author)

  14. kCCA Transformation-Based Radiometric Normalization of Multi-Temporal Satellite Images

    Directory of Open Access Journals (Sweden)

    Yang Bai

    2018-03-01

    Full Text Available Radiation normalization is an essential pre-processing step for generating high-quality satellite sequence images. However, most radiometric normalization methods are linear, and they cannot eliminate the regular nonlinear spectral differences. Here we introduce the well-established kernel canonical correlation analysis (kCCA into radiometric normalization for the first time to overcome this problem, which leads to a new kernel method. It can maximally reduce the image differences among multi-temporal images regardless of the imaging conditions and the reflectivity difference. It also perfectly eliminates the impact of nonlinear changes caused by seasonal variation of natural objects. Comparisons with the multivariate alteration detection (CCA-based normalization and the histogram matching, on Gaofen-1 (GF-1 data, indicate that the kCCA-based normalization can preserve more similarity and better correlation between an image-pair and effectively avoid the color error propagation. The proposed method not only builds the common scale or reference to make the radiometric consistency among GF-1 image sequences, but also highlights the interesting spectral changes while eliminates less interesting spectral changes. Our method enables the application of GF-1 data for change detection, land-use, land-cover change detection etc.

  15. Radiometric Correction of Multitemporal Hyperspectral Uas Image Mosaics of Seedling Stands

    Science.gov (United States)

    Markelin, L.; Honkavaara, E.; Näsi, R.; Viljanen, N.; Rosnell, T.; Hakala, T.; Vastaranta, M.; Koivisto, T.; Holopainen, M.

    2017-10-01

    Novel miniaturized multi- and hyperspectral imaging sensors on board of unmanned aerial vehicles have recently shown great potential in various environmental monitoring and measuring tasks such as precision agriculture and forest management. These systems can be used to collect dense 3D point clouds and spectral information over small areas such as single forest stands or sample plots. Accurate radiometric processing and atmospheric correction is required when data sets from different dates and sensors, collected in varying illumination conditions, are combined. Performance of novel radiometric block adjustment method, developed at Finnish Geospatial Research Institute, is evaluated with multitemporal hyperspectral data set of seedling stands collected during spring and summer 2016. Illumination conditions during campaigns varied from bright to overcast. We use two different methods to produce homogenous image mosaics and hyperspectral point clouds: image-wise relative correction and image-wise relative correction with BRDF. Radiometric datasets are converted to reflectance using reference panels and changes in reflectance spectra is analysed. Tested methods improved image mosaic homogeneity by 5 % to 25 %. Results show that the evaluated method can produce consistent reflectance mosaics and reflectance spectra shape between different areas and dates.

  16. RADIOMETRIC CORRECTION OF MULTITEMPORAL HYPERSPECTRAL UAS IMAGE MOSAICS OF SEEDLING STANDS

    Directory of Open Access Journals (Sweden)

    L. Markelin

    2017-10-01

    Full Text Available Novel miniaturized multi- and hyperspectral imaging sensors on board of unmanned aerial vehicles have recently shown great potential in various environmental monitoring and measuring tasks such as precision agriculture and forest management. These systems can be used to collect dense 3D point clouds and spectral information over small areas such as single forest stands or sample plots. Accurate radiometric processing and atmospheric correction is required when data sets from different dates and sensors, collected in varying illumination conditions, are combined. Performance of novel radiometric block adjustment method, developed at Finnish Geospatial Research Institute, is evaluated with multitemporal hyperspectral data set of seedling stands collected during spring and summer 2016. Illumination conditions during campaigns varied from bright to overcast. We use two different methods to produce homogenous image mosaics and hyperspectral point clouds: image-wise relative correction and image-wise relative correction with BRDF. Radiometric datasets are converted to reflectance using reference panels and changes in reflectance spectra is analysed. Tested methods improved image mosaic homogeneity by 5 % to 25 %. Results show that the evaluated method can produce consistent reflectance mosaics and reflectance spectra shape between different areas and dates.

  17. Development of a standard operating procedure for mammography equipment used in calibration of ionized chambers

    International Nuclear Information System (INIS)

    Rodrigues, Yklys Santos; Potiens, Maria da Penha Albuquerque

    2011-01-01

    Mammography is one widely used technique in the detection of breast cancer. In order to optimize the results achieving better images with lower dose rates, a quality assurance programme must be applied to the equipment. Some control tests use ionization chambers to measure air kerma and other quantities. These tests can only be reliable if the ionization chambers used on them are correctly calibrated. In the present work, it was developed a standard operating procedure (SOP) for quality control tests in a commercial mammography equipment installed in the Calibration Laboratory (LCI) at IPEN - Brazilian Institute for energy and nuclear research). Seven tests were performed in the equipment: Tube voltage and exposition time accuracy and reproducibility, linearity and reproducibility of Air kerma and Half Value Layer (HVL). Then, it was made a measurement of the air kerma in the mammography equipment, using a reference ionization chamber with traceability to a primary laboratory in Germany (Physikalisch-Technische Bundesanstalt - PTB), that was later compared with the air kerma measured in an industrial irradiator. This industrial X-ray generator was recently used in the implementation of X-radiation Standards beams, mammography level, following the Standard IEC 61267. The HVL values varied from 0.36 (25kV) to 0.41 mmA1 (35kV), and the measured air kerma rates were between 9.78 and 17.97 mGy/min. (author)

  18. 40 CFR 91.424 - Dilute sampling procedure-CVS calibration.

    Science.gov (United States)

    2010-07-01

    ... radius or American Society of Mechanical Engineers (ASME) flow nozzles are considered equivalent if..., kPa (inches fluid). (iv) A linear least squares fit is performed to generate the calibration... density of exhaust hydrocarbons. (5) The gravimetric mass is subtracted from the CVS measured mass and...

  19. Microwave and Millimeter-Wave Radiometric Studies of Temperature, Water Vapor and Clouds

    Energy Technology Data Exchange (ETDEWEB)

    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

  20. Radiometric dating by alpha spectrometry on uranium series nuclides

    NARCIS (Netherlands)

    Wijk, Albert van der

    1987-01-01

    De Engelse titel van dit proegschrift \\"Radiometric Dating by Alpha Spectometry on Uranium Series Nuclides\\" kan in het Nederlands wellicht het best worden weergegeven door \\"ouderdomsdbepalingen door stralingsmeting aan kernen uit de uraniumreeks met behulp van alfaspectometrie\\". In dit laatste

  1. Calibration of clinical dosemeters in the IAEA water phantom

    International Nuclear Information System (INIS)

    Caldas, L.V.E.; Albuquerque, M.P.P.

    1994-01-01

    The procedures recommended by the IAEA Code of Practice were applied at the Calibration Laboratory of Sao Paulo in order to provide in the future the clinical dosemeters users with absorbed dose to water calibration factors for Cobalt 60 radiation beams. In this work the clinical dosemeters were calibrated free in air and in water, and the results were compared, using conversion factors. The several tested clinical dosemeters of different manufacturers and models belong to the laboratory and to hospitals. For the measurements in water the IAEA cubic water phantom was used. The dosemeters were all calibrated free in air in terms of air kerma, and the calibration factors in terms of absorbed dose to water were obtained through conversion factors. the same dosemeters were also calibrated into the water phantom. Good agreement was found between the two methods, the differences were always less than 0.5%. The data obtained during this work show that when the dosemeters are used only in Cobalt 60 radiation and the users apply in the hospital routine work the IAEA Code of Practice, the calibration can be performed directly in the water phantom. This procedure provides the useful calibration factors in terms of absorbed dose to water

  2. Calibration of photon and beta ray sources used in brachytherapy. Guidelines on standardized procedures at Secondary Standards Dosimetry Laboratories

    International Nuclear Information System (INIS)

    2004-03-01

    It has generally been recognized that international harmonization in radiotherapy dosimetry is essential. Consequently, the IAEA has given much effort to this, for example by publishing a number of reports in the Technical Reports Series (TRS) for external beam dosimetry, most notably TRS-277 and more recently TRS-398. Both of these reports describe in detail the steps to be taken for absorbed dose determination in water and they are often referred to as 'dosimetry protocols'. Similar to TRS-277, it is expected that TRS-398 will be adopted or used as a model by a large number of countries as their national protocol. In 1996, the IAEA established a calibration service for low dose rate (LDR) 137 Cs brachytherapy sources, which is the most widely used source for treatment of gynecological cancer. To further enhance harmonization in brachytherapy dosimetry, the IAEA published in 1999 IAEA-TECDOC-1079 entitled 'Calibration of Brachytherapy Sources. Guidelines on Standardized Procedures for the Calibration of Brachytherapy Sources at Secondary Standard Dosimetry Laboratories (SSDLs) and Hospitals'. The report was well received and was distributed in a large number of copies to the members of the IAEA/WHO network of SSDLs and to medical physicists working with brachytherapy. The present report is an update of the aforementioned TECDOC. Whereas TECDOC-1079 described methods for calibrating brachytherapy sources with photon energies at or above those of 192 Ir, the current report has a wider scope in that it deals with standardization of calibration of all the most commonly used brachytherapy sources, including both photon and beta emitting sources. The latter sources have been in use for a few decades already, but their calibration methods have been unclear. Methods are also described for calibrating sources used in the rapidly growing field of cardiovascular angioplasty. In this application, irradiation of the vessel wall is done in an attempt to prevent restenosis after

  3. [Fundamental aspects for accrediting medical equipment calibration laboratories in Colombia].

    Science.gov (United States)

    Llamosa-Rincón, Luis E; López-Isaza, Giovanni A; Villarreal-Castro, Milton F

    2010-02-01

    Analysing the fundamental methodological aspects which should be considered when drawing up calibration procedure for electro-medical equipment, thereby permitting international standard-based accreditation of electro-medical metrology laboratories in Colombia. NTC-ISO-IEC 17025:2005 and GTC-51-based procedures for calibrating electro-medical equipment were implemented and then used as patterns. The mathematical model for determining the estimated uncertainty value when calibrating electro-medical equipment for accreditation by the Electrical Variable Metrology Laboratory's Electro-medical Equipment Calibration Area accredited in compliance with Superintendence of Industry and Commerce Resolution 25771 May 26th 2009 consists of two equations depending on the case; they are: E = (Ai + sigmaAi) - (Ar + sigmaAr + deltaAr1) and E = (Ai + sigmaAi) - (Ar + sigmaA + deltaAr1). The mathematical modelling implemented for measuring uncertainty in the Universidad Tecnológica de Pereira's Electrical Variable Metrology Laboratory (Electro-medical Equipment Calibration Area) will become a good guide for calibration initiated in other laboratories in Colombia and Latin-America.

  4. Radioactive standards and calibration methods for contamination monitoring instruments

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Makoto [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-06-01

    Contamination monitoring in the facilities for handling unsealed radioactive materials is one of the most important procedures for radiation protection as well as radiation dose monitoring. For implementation of the proper contamination monitoring, radiation measuring instruments should not only be suitable to the purpose of monitoring, but also be well calibrated for the objective qualities of measurement. In the calibration of contamination monitoring instruments, quality reference activities need to be used. They are supplied in different such as extended sources, radioactive solutions or radioactive gases. These reference activities must be traceable to the national standards or equivalent standards. On the other hand, the appropriate calibration methods must be applied for each type of contamination monitoring instruments. In this paper, the concepts of calibration for contamination monitoring instruments, reference sources, determination methods of reference quantities and practical calibration methods of contamination monitoring instruments, including the procedures carried out in Japan Atomic Energy Research Institute and some relevant experimental data. (G.K.)

  5. Non-uniformity calibration for MWIR polarization imagery obtained with integrated microgrid polarimeters

    Science.gov (United States)

    Liu, Hai-Zheng; Shi, Ze-Lin; Feng, Bin; Hui, Bin; Zhao, Yao-Hong

    2016-03-01

    Integrating microgrid polarimeters on focal plane array (FPA) of an infrared detector causes non-uniformity of polarization response. In order to reduce the effect of polarization non-uniformity, this paper constructs an experimental setup for capturing raw flat-field images and proposes a procedure for acquiring non-uniform calibration (NUC) matrix and calibrating raw polarization images. The proposed procedure takes the incident radiation as a polarization vector and offers a calibration matrix for each pixel. Both our matrix calibration and two-point calibration are applied to our mid-wavelength infrared (MWIR) polarization imaging system with integrated microgrid polarimeters. Compared with two point calibration, our matrix calibration reduces non-uniformity by 30 40% under condition of flat-field data test with polarization. The ourdoor scene observation experiment indicates that our calibration can effectively reduce polarization non-uniformity and improve the image quality of our MWIR polarization imaging system.

  6. Accurate and Simple Calibration of DLP Projector Systems

    DEFF Research Database (Denmark)

    Wilm, Jakob; Olesen, Oline Vinter; Larsen, Rasmus

    2014-01-01

    does not rely on an initial camera calibration, and so does not carry over the error into projector calibration. A radial interpolation scheme is used to convert features coordinates into projector space, thereby allowing for a very accurate procedure. This allows for highly accurate determination...

  7. Substoichiometric method in the simple radiometric analysis

    International Nuclear Information System (INIS)

    Ikeda, N.; Noguchi, K.

    1979-01-01

    The substoichiometric method is applied to simple radiometric analysis. Two methods - the standard reagent method and the standard sample method - are proposed. The validity of the principle of the methods is verified experimentally in the determination of silver by the precipitation method, or of zinc by the ion-exchange or solvent-extraction method. The proposed methods are simple and rapid compared with the conventional superstoichiometric method. (author)

  8. A study on the radiometric method for evaluating element migration from plastic packagings to its contents

    International Nuclear Information System (INIS)

    Soares, Eufemia Paez

    2008-01-01

    Over the past few years, problems related to food contamination by substances or elements that can be a risk to human health have became a concern, not only to government authorities, but to the general population as well. Within this context, plastic packaging can constitute a source of food contamination since plastic manufacturing processes involve the use of catalysts and different types of additives that may contain toxic elements. When food comes into contact with this packaging, components of the package may migrate to the food. In order to control the material used as food packaging, the National Health Surveillance Agency (ANVISA) in Brazil, has established boundary values of migrant substances and procedures to determine migration from plastic packagings to food. In this study the radiometric method was evaluated for element migration determination from plastic packaging to food simulating or to the food itself. This radiometric method consisted in irradiating plastic packaging samples with a thermal neutron flux from the IEA-R1 nuclear research reactor in order to produce radionuclides of elements present in the packagings. The irradiated plastic was then exposed to food simulant or food for element migration. Gamma ray spectrometry was used to measure radioactivity in the simulant or food in order to quantify the migration. The food simulating types and experimental conditions were established according to the ANVISA regulations. Element migration was studied for plastic packaging used for soft drinks, drinking water, milk, dairy products, juices and fatty foods. In the instrumental neutron activation analysis of these packagings the presence of As, Cd, Cr, Co and Sb II was verified. Results obtained from the migration experiments by the radiometric method indicated that Cd, Co, Cr and Sb present in these plastics migrated to the simulant or to the food. In some packagings, the migration of only some of these elements was observed. In these cases the

  9. Limulus test for pyrogens and radiometric sterility tests on radiopharmaceuticals. Part of a coordinated programme

    International Nuclear Information System (INIS)

    Gopal, N.G.S.

    1976-10-01

    Sterility testing of radiopharmaceuticals prepared at BARC were carried out using the radiometric technique (Radiometric detection of the metabolic product 14 Co 2 ). Batches of different radiopharmaceuticals were tested for pyrogen using the limulus lysate method and the results were compared with the rabbit method. The results of sterility test on 202 batches of 19 different radiopharmaceuticals show that the radiometric method can be used for sterility testing of radiopharmaceuticals labelled with 35 S, 51 Cr, 57 Co, 59 Fe, 82 Br, 86 Rb, sup(99m)Tc, sup(113m)In, 125 I and 169 Yb. The radiometric test proves to be more rapid than the conventional one for the sterility testing of such radiopharmaceuticals. Detection time is between 6-21 hours. In the case of 131 I-labelled radiopharmaceuticals and in the case of chlormerodrin-Hg-203, it was found an interference due to volatile species (sup(131m)Xe in the case of 131 I and some volatile mercury form in the case of chlormerodrin). In these cases it would be possible to carry out the radiometric sterility test after separation of the microorganisms from the radioactive material (by filtration). The limulus lysate method can be employed for control of various pyrogen-prone raw materials and radiopharmaceuticals. Such method is the only method at present available for detecting the low level pyrogen contamination in intrathecal injections. The limulus test is more rapid than the rabbit test

  10. The construction of a radiometric calibration facility at Lanseria Airport, Republic of South Africa

    International Nuclear Information System (INIS)

    Corner, B.; Smit, C.J.B.

    1982-10-01

    The construction of standard sources suitable for the calibration of airborne and truck-mounted gamma-spectrometer systems is described. Four sources were built, three of which were doped with preselected quantities of uranium, thorium or potassium. A fourth source was left barren so as to provide a measure of the background radiation in the area. The sources are 8 m in diameter, 0,35 m thick and are recessed into the disused northern portion of runway 17 at Lanseria Airport, north of Johannesburg. Adopted concentrations of the major radioelements in the sources are: 6,24 % K 2 O in the potassium source, 65,0 ppm U 3 O 8 in the uranium source and 150 ppm ThO 2 in the thorium source

  11. Experimental Validation of an Efficient Fan-Beam Calibration Procedure for k-Nearest Neighbor Position Estimation in Monolithic Scintillator Detectors

    Science.gov (United States)

    Borghi, Giacomo; Tabacchini, Valerio; Seifert, Stefan; Schaart, Dennis R.

    2015-02-01

    Monolithic scintillator detectors can achieve excellent spatial resolution and coincidence resolving time. However, their practical use for positron emission tomography (PET) and other applications in the medical imaging field is still limited due to drawbacks of the different methods used to estimate the position of interaction. Common statistical methods for example require the collection of an extensive dataset of reference events with a narrow pencil beam aimed at a fine grid of reference positions. Such procedures are time consuming and not straightforwardly implemented in systems composed of many detectors. Here, we experimentally demonstrate for the first time a new calibration procedure for k-nearest neighbor ( k-NN) position estimation that utilizes reference data acquired with a fan beam. The procedure is tested on two detectors consisting of 16 mm ×16 mm ×10 mm and 16 mm ×16 mm ×20 mm monolithic, Ca-codoped LSO:Ce crystals and digital photon counter (DPC) arrays. For both detectors, the spatial resolution and the bias obtained with the new method are found to be practically the same as those obtained with the previously used method based on pencil-beam irradiation, while the calibration time is reduced by a factor of 20. Specifically, a FWHM of 1.1 mm and a FWTM of 2.7 mm were obtained using the fan-beam method with the 10 mm crystal, whereas a FWHM of 1.5 mm and a FWTM of 6 mm were achieved with the 20 mm crystal. Using a fan beam made with a 4.5 MBq 22Na point-source and a tungsten slit collimator with 0.5 mm aperture, the total measurement time needed to acquire the reference dataset was 3 hours for the thinner crystal and 2 hours for the thicker one.

  12. Wind Tunnel Balance Calibration: Are 1,000,000 Data Points Enough?

    Science.gov (United States)

    Rhew, Ray D.; Parker, Peter A.

    2016-01-01

    Measurement systems are typically calibrated based on standard practices established by a metrology standards laboratory, for example the National Institute for Standards and Technology (NIST), or dictated by an organization's metrology manual. Therefore, the calibration is designed and executed according to an established procedure. However, for many aerodynamic research measurement systems a universally accepted standard, traceable approach does not exist. Therefore, a strategy for how to develop a calibration protocol is left to the developer or user to define based on experience and recommended practice in their respective industry. Wind tunnel balances are one such measurement system. Many different calibration systems, load schedules and procedures have been developed for balances with little consensus on a recommended approach. Especially lacking is guidance the number of calibration data points needed. Regrettably, the number of data points tends to be correlated with the perceived quality of the calibration. Often, the number of data points is associated with ones ability to generate the data rather than by a defined need in support of measurement objectives. Hence the title of the paper was conceived to challenge recent observations in the wind tunnel balance community that shows an ever increasing desire for more data points per calibration absent of guidance to determine when there are enough. This paper presents fundamental concepts and theory to aid in the development of calibration procedures for wind tunnel balances and provides a framework that is generally applicable to the characterization and calibration of other measurement systems. Questions that need to be answered are for example: What constitutes an adequate calibration? How much data are needed in the calibration? How good is the calibration? This paper will assist a practitioner in answering these questions by presenting an underlying theory on how to evaluate a calibration based on

  13. The study of new calibration features in the Harshaw TLD system

    International Nuclear Information System (INIS)

    Luo, L.Z.

    2005-01-01

    Full text: In the Harshaw TLD system, there are three key calibration procedures; the reader, the dosimeter and the algorithm. These procedures must be properly calibrated for the system to achieve the optimum results. For the conventional reader and dosimeter calibration, Harshaw recommends a pre-fade and a post-fade of 24 - 48 hours when calibrating the system. Harshaw also emphasizes that keeping the fade time consistent is important to maintain the quality of the system performance. In recent years, new calibration features have been introduced into the operating system. These new features are auto calibration, auto QC and auto blank, and they give the user the ability to set up the clear-expose-read performed automatically in a sequence for each dosimeter. This saves processing time and keeps the fade time the same. However, since the fade time is near zero, will it affect the TLD system calibration factors? What should the user expect? This paper presents a study of the effect of auto calibration / auto QC to the TLD operation. (author)

  14. ANALYZING SPECTRAL CHARACTERISTICS OF SHADOW AREA FROM ADS-40 HIGH RADIOMETRIC RESOLUTION AERIAL IMAGES

    Directory of Open Access Journals (Sweden)

    Y.-T. Hsieh

    2016-06-01

    Full Text Available 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.

  15. Mercury CEM Calibration

    Energy Technology Data Exchange (ETDEWEB)

    John Schabron; Joseph Rovani; Mark Sanderson

    2008-02-29

    Mercury continuous emissions monitoring systems (CEMS) are being implemented in over 800 coal-fired power plant stacks. The power industry desires to conduct at least a full year of monitoring before the formal monitoring and reporting requirement begins on January 1, 2009. It is important for the industry to have available reliable, turnkey equipment from CEM vendors. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor generators. The generators are used to calibrate mercury CEMs at power plant sites. The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005 requires that calibration be performed with NIST-traceable standards (Federal Register 2007). Traceability procedures will be defined by EPA. An initial draft traceability protocol was issued by EPA in May 2007 for comment. In August 2007, EPA issued an interim traceability protocol for elemental mercury generators (EPA 2007). The protocol is based on the actual analysis of the output of each calibration unit at several concentration levels ranging initially from about 2-40 {micro}g/m{sup 3} elemental mercury, and in the future down to 0.2 {micro}g/m{sup 3}, and this analysis will be directly traceable to analyses by NIST. The document is divided into two separate sections. The first deals with the qualification of generators by the vendors for use in mercury CEM calibration. The second describes the procedure that the vendors must use to certify the generator models that meet the qualification specifications. The NIST traceable certification is performance based, traceable to analysis using isotope dilution inductively coupled plasma/mass spectrometry performed by NIST in Gaithersburg, MD. The

  16. Calibration of ionization chambers used in LDR brachytherapy

    International Nuclear Information System (INIS)

    Alvarez, Oscar T.B.; Caldas, Linda V.E.

    2005-01-01

    In this work was developed a calibration procedure of well-type ionization chambers used for measurements of I-125, seed type. It was used as a standard an ionization chamber Capintec CRC-15BT, with calibration certificate of the University of Wisconsin. It were calibrated two well-type ionization chambers of Capintec CRC-15R model. A source of I-125 was used in clinical use (18.5 to 7.4 MBq). The results showed that with the application of calibration factors was possible to decrease read deviate from 16% to just 1.0%

  17. Project of an integrated calibration laboratory of instruments at IPEN; Projeto de um laboratorio integrado de calibracao de instrumentos no IPEN

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Gustavo Adolfo San Jose

    2009-07-01

    The Calibration Laboratory of Instruments of Instituto de Pesquisas Energeticas e Nucleares offers calibration services of radiation detectors used in radioprotection, diagnostic radiology and radiotherapy, for IPEN and for external facilities (public and private). One part of its facilities is located in the main building, along with other laboratories and study rooms, and another part in an isolated building called Bunker. For the optimization, modernization and specially the safety, the laboratories in the main building shall be transferred to an isolated place. In this work, a project of an integrated laboratory for calibration of instruments was developed, and it will be an expansion of the current Calibration Laboratory of Instruments of IPEN. Therefore, a series of radiometric monitoring of the chosen localization of the future laboratory was realized, and all staff needs (dimensions and disposition of the study rooms and laboratories) were defined. In this project, the laboratories with X ray equipment, alpha and beta radiation sources were located at an isolated part of the building, and the wall shielding was determined, depending on the use of each laboratory. (author)

  18. An analysis of new techniqes for radiometric correction of LANDSAT-4 Thematic Mapper images. [Terrebonne Bay, Louisiana and Grand Bahamas scenes

    Science.gov (United States)

    Kogut, J.; Larduinat, E.; Fitzgerald, M.

    1983-01-01

    The utility of methods for generating TM RLUTS which can improve the quality of the resultant images was investigated. The TM-CCT-ADDS tape was changed to account for a different collection window for the calibration data. Several scenes of Terrebonne Bay, Louisiana and the Grand Bahamas were analyzed to evaluate the radiometric corrections operationally applied to the image data and to investigate several techniques for reducing striping in the images. Printer plots for the TM shutter data were produced and detector statistics were compiled and plotted. These statistics included various combinations of the average shutter counts for each scan before and after DC restore for forward and reverse scans. Results show that striping is caused by the detectors becoming saturated when they view a bright cloud and depress the DC restore level.

  19. Balanced calibration of resonant piezoelectric RL shunts with quasi-static background flexibility correction

    DEFF Research Database (Denmark)

    Høgsberg, Jan Becker; Krenk, Steen

    2015-01-01

    Resonant RL shunt circuits constitute a robust approach to piezoelectric damping, where the performance with respect to damping of flexible structures requires a precise calibration of the corresponding circuit components. The balanced calibration procedure of the present paper is based on equal ...... that the procedure leads to equal modal damping and effective response reduction, even for rather indirect placement of the transducer, provided that the correction for background flexibility is included in the calibration procedure....

  20. Automation is an Effective Way to Improve Quality of Verification (Calibration) of Measuring Instruments

    Science.gov (United States)

    Golobokov, M.; Danilevich, S.

    2018-04-01

    In order to assess calibration reliability and automate such assessment, procedures for data collection and simulation study of thermal imager calibration procedure have been elaborated. The existing calibration techniques do not always provide high reliability. A new method for analyzing the existing calibration techniques and developing new efficient ones has been suggested and tested. A type of software has been studied that allows generating instrument calibration reports automatically, monitoring their proper configuration, processing measurement results and assessing instrument validity. The use of such software allows reducing man-hours spent on finalization of calibration data 2 to 5 times and eliminating a whole set of typical operator errors.

  1. Procedure for the determination of gap and base ground surface configurations beneath the bottom plate of storage tanks using neutron gauging inspection techniques : including radiation safety procedure and emergency procedure

    International Nuclear Information System (INIS)

    Jaafar Abdullah

    1993-01-01

    The procedure is intended for the neutron gauging inspection of gap between the bottom plate and the foundation of bulk storage tanks, which potentially exhibit uneven sinking of the bottom plate and the foundation. Its describes the requirements for the performance of neutron back scattered inspection techniques (or radiometric non-destructive evaluation techniques), using an isotopic neutron source associated with neutron detecting systems, to detect and size the gap between the bottom plate and the foundations as well as to quantify the presence of hydrogenous materials (e.g. oil or water) underneath the bottom plate. This procedure is not only outline the requirements for the neutron gauging inspection, but also describes the requirements which shall be taken into account in formulating the radiation safety and emergency procedures for the neutron gauging inspection works

  2. Calibration of radiation monitoring instruments

    International Nuclear Information System (INIS)

    1973-01-01

    Radiation protection is dependent on good radiation monitoring, and properly calibrated instruments are essential for this work. Simple procedures for periodically checking and recalibrating different kinds of radiation monitoring instruments are shown in this training film

  3. Calibration of radiation monitoring instruments

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1974-12-31

    Radiation protection is dependent on good radiation monitoring, and properly calibrated instruments are essential for this work. Simple procedures for periodically checking and recalibrating different kinds of radiation monitoring instruments are shown in this training film

  4. Radiometric analysis performed by the Environment Monitoring Service from IPEN (Institute of Energy and Nuclear Research), Brazil, between 1988 and 1991; Analises radiometricas realizadas pelo Servico de Monitoracao Ambiental do IPEN de 1988 a 1991

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, L; Nisti, M B; Pecequilo, B R.S.

    1993-03-01

    This report presents the radiometric analyses made by the Environmental Monitoring Service from the Institute of Energy and Nuclear Research (IPEN), Brazil, in the period 1988-1991. The experimental procedures, the products analysed and their respective quantities are described. (F.E.). 11 refs, 3 tabs.

  5. preliminary geological and radiometric studies of granitoids of zing

    African Journals Online (AJOL)

    DJFLEX

    laboratory of Geology Department, Federal University of. Technology, Yola where they were thin sectioned and petrographically studied using a high magnification polarising microscope. Canada balsam was used as the mounting medium. Radiometric survey was carried out using a McPhar model TC-33A portable gamma ...

  6. Study of a new radiometric sterility test in radiopharmaceuticals

    International Nuclear Information System (INIS)

    Sanchez P, A.R.

    1976-01-01

    A new radiometric method is studied for the determination of sterility. It is based on a culture marked with carbon-14 and the measurement by liquid scintillation of the radioactivity of the gaseous products released after a short period of incubation. The studied samples consisted in nonradioactive solutions and different radiopharmaceuticals, through a regulated current of nitrogen there is a transportation of gaseous and volatile products produced in each flask, which were received in a liquid scintillation vial. The experimental data permit to conclude that through the radiometric method the results can be obtained after 24 hours or less of incubation, instead of a period of several days which was necessary with the traditional process. Due to the sensitivity of the method it is possible to inoculate a minimum volume of sample, this is important in the case of the preparation of little parts for injection as it occurs generally with the pharmaceuticals. (author)

  7. Radiometric measurement independent of profile. Belt weighers

    International Nuclear Information System (INIS)

    Otto, J.

    1986-01-01

    Radiometric measuring techniques allow contactless determination of the material carried by belt conveyors. Data defining the material is obtained via attenuation of gamma rays passing through the material on the belt. The method applies the absorption law according to Lambert-Beer, which has to be corrected by a build-up factor because of the stray radiation induced by the Compton effect. The profile-dependent error observed with conventional radiometric belt weighers is caused by the non-linearity of the absorption law in connection with the simultaneous summation of the various partial rays in a detector. The scanning method allows separate evaluation of the partial rays' attenuation and thus yields the correct data of the material carried, regardless of the profile. The scanning method is applied on a finite number of scanning sections, and a residual error has to be taken into account. The stochastics of quantum emission and absorption leads to an error whose expectation value is to be taken into account in the scanning algorithm. As the conveyor belt is in motion during the process of measurements, only part of the material conveyed is irradiated. The resulting assessment error is investigated as a function of the autocorrelation function of the material on the belt. (orig./HP) [de

  8. Helicopter-borne magnetic, electromagnetic and radiometric geophysical survey in Mauken, Maalselv, Troms

    International Nuclear Information System (INIS)

    Rodionov, Alexei; Koziel, Janusz; Lynum, Rolf

    2012-01-01

    NGU conducted an airborne geophysical survey in Mauken area in June 2011 as a part of MINN project. This report describes and documents the acquisition, processing and visualization of recorded datasets. The geophysical survey results reported herein are 3680 line km. The modified Geotech Ltd. Hummingbird frequency domain system supplemented by optically pumped cesium magnetometer and 1024 channels RSX-5 spectrometer was used for data acquisition. The survey was flown with 200 m line spacing, line direction of 33 degrees NE and average speed 88km/h. The average terrain clearance of the bird was 45m. Collected data were processed in NGU using Geosoft Oasis Montaj software. Raw total magnetic field data were corrected for diurnal variation and levelled using standard micro levelling algorithm. EM data were filtered and levelled using both -automated and manual levelling procedure. Apparent resistivity was calculated from in-phase and quadrature data for each of the five frequencies separately using a homogeneous half space model. Apparent resistivity dataset was filtered and levelled. Radiometric data were processed using standard procedures recommended by International Atomic Energy Association. All data were gridded with the cell size of 50 m and presented as a shaded relief maps at the scale of 1:50 000. (Author)

  9. Helicopter-borne magnetic, electromagnetic and radiometric geophysical survey in Mauken, Maalselv, Troms

    Energy Technology Data Exchange (ETDEWEB)

    Rodionov, Alexei; Koziel, Janusz; Lynum, Rolf

    2012-07-01

    NGU conducted an airborne geophysical survey in Mauken area in June 2011 as a part of MINN project. This report describes and documents the acquisition, processing and visualization of recorded datasets. The geophysical survey results reported herein are 3680 line km. The modified Geotech Ltd. Hummingbird frequency domain system supplemented by optically pumped cesium magnetometer and 1024 channels RSX-5 spectrometer was used for data acquisition. The survey was flown with 200 m line spacing, line direction of 33 degrees NE and average speed 88km/h. The average terrain clearance of the bird was 45m. Collected data were processed in NGU using Geosoft Oasis Montaj software. Raw total magnetic field data were corrected for diurnal variation and levelled using standard micro levelling algorithm. EM data were filtered and levelled using both -automated and manual levelling procedure. Apparent resistivity was calculated from in-phase and quadrature data for each of the five frequencies separately using a homogeneous half space model. Apparent resistivity dataset was filtered and levelled. Radiometric data were processed using standard procedures recommended by International Atomic Energy Association. All data were gridded with the cell size of 50 m and presented as a shaded relief maps at the scale of 1:50 000. (Author)

  10. A first in-flight absolute calibration of the Chilean Earth Observation Satellite

    Science.gov (United States)

    Mattar, C.; Hernández, J.; Santamaría-Artigas, A.; Durán-Alarcón, C.; Olivera-Guerra, L.; Inzunza, M.; Tapia, D.; Escobar-lavín, E.

    2014-06-01

    This work describes the first in-flight absolute calibration of the "Sistema Satelital para la Observación de la Tierra" (SSOT or Fasat-C). It was performed on January 29th 2013 at Antumapu site located in the southern area of Santiago, Chile. A description of the procedure is presented which includes both ground measurement and atmospheric characterization. The Chilean satellite for Earth observation carries on board a "New AstroSat Optical Modular Instrument" (NAOMI) high-resolution pushbroom imager which provides a 1.45 m ground sampling distance in the panchromatic (0.455-0.744 μm) channel and a 5.8 m ground sampling distance for the green (0.455-0.52 μm), blue (0.528-0.588 μm), red (0.625-0.695 μm) and near-infrared (0.758-0.881 μm) channels from a 620 km orbit. Radiometric calibration was carried out in order to estimate the land leaving radiance and bidirectional reflectance at the top of the atmosphere. To correct the reflectance data for atmospheric effects, the Second Simulation of a Satellite Signal in the Solar Spectrum (6S) code was used. Aerosol Optical Depth (AOD), water vapor and ozone content were obtained from MOD04, MOD05 and MOD07 products respectively, which are derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) data. Statistical results such as BIAS, SIGMA and RMSE were calculated for the comparison between surface reflectance values and in situ measurements. Results show that the overall accuracy of the atmospherically corrected surface reflectance calculated from Fasat-C imagery can be estimated to around ±5%, with a R2 coefficient of 0.939 between atmospherically corrected reflectance values and in situ measurements. The atmospheric correction applied in this work by combining MODIS data and the 6S radiative transfer code could be used for further calibration of the Fasat-C images, although in situ atmospheric irradiance measurements are necessary to estimate reliable values of surface reflectance. Future

  11. The KLOE online calibration system

    International Nuclear Information System (INIS)

    Pasqualucci, E.; Alexander, G.; Aloisio, A.

    2001-01-01

    Based on all the features of the KLOE online software, the online calibration system performs current calibration quality checking in real time and starts automatically new calibration procedures when needed. A calibration manager process controls the system, implementing the interface to the online system, receiving information from the run control and translating its state transitions to a separate state machine. It acts as a 'calibration run controller' and performs failure recovery when requested by a set of process checkers. The core of the system is a multi-threaded OO histogram server that receives histogramming commands by remote processes and operates on local ROOT histograms. A client library and C, fortran and C++ application interface libraries allow the user to connect and define his own histogram or read histograms owned by others using an book-like interface. Several calibration processes running in parallel in a distributed, multiplatform environment can fill the same histograms, allowing fast external information check. A monitor thread allow remote browsing for visual inspection. Pre-filtered data are read in non-privileged spy mode from the data acquisition system via the Kloe Integrated Dataflow. The main characteristics of the system are presented

  12. The ATLAS Electromagnetic Calorimeter Calibration Workshop

    CERN Multimedia

    Hong Ma; Isabelle Wingerter

    The ATLAS Electromagnetic Calorimeter Calibration Workshop took place at LAPP-Annecy from the 1st to the 3rd of October; 45 people attended the workshop. A detailed program was setup before the workshop. The agenda was organised around very focused presentations where questions were raised to allow arguments to be exchanged and answers to be proposed. The main topics were: Electronics calibration Handling of problematic channels Cluster level corrections for electrons and photons Absolute energy scale Streams for calibration samples Calibration constants processing Learning from commissioning Forty-five people attended the workshop. The workshop was on the whole lively and fruitful. Based on years of experience with test beam analysis and Monte Carlo simulation, and the recent operation of the detector in the commissioning, the methods to calibrate the electromagnetic calorimeter are well known. Some of the procedures are being exercised in the commisssioning, which have demonstrated the c...

  13. Toward a standard line for use in multibeam echo sounder calibration

    Science.gov (United States)

    Weber, Thomas C.; Rice, Glen; Smith, Michael

    2018-06-01

    A procedure is suggested in which a relative calibration for the intensity output of a multibeam echo sounder (MBES) can be performed. This procedure identifies a common survey line (i.e., a standard line), over which acoustic backscatter from the seafloor is collected with multiple MBES systems or by the same system multiple times. A location on the standard line which exhibits temporal stability in its seafloor backscatter response is used to bring the intensity output of the multiple MBES systems to a common reference. This relative calibration procedure has utility for MBES users wishing to generate an aggregate seafloor backscatter mosaic using multiple systems, revisiting an area to detect changes in substrate type, and comparing substrate types in the same general area but with different systems or different system settings. The calibration procedure is demonstrated using three different MBES systems over 3 different years in New Castle, NH, USA.

  14. Marine X-band Weather Radar Data Calibration

    DEFF Research Database (Denmark)

    Thorndahl, Søren Liedtke; Rasmussen, Michael R.

    2012-01-01

    estimates. This paper presents some of the challenges in small marine X-band radar calibration by comparing three calibration procedures for assessing the relationship between radar and rain gauge data. Validation shows similar results for precipitation volumes but more diverse results on peak rain......Application of weather radar data in urban hydrology is evolving and radar data is now applied for both modelling, analysis, and real time control purposes. In these contexts, it is allimportant that the radar data is well calibrated and adjusted in order to obtain valid quantitative precipitation...

  15. Calibration of personal dosimeters: Quantities and terminology

    International Nuclear Information System (INIS)

    Aleinikov, V.E.

    1999-01-01

    The numerical results obtained in the interpretation of individual monitoring of external radiation depend not only on the accurate calibration of the radiation measurement instruments involved, but also on the definition of the quantities in term of which these instruments are calibrated The absence of uniformity in terminology not only makes it difficult to understand properly the scientific and technical literature but can also lead to incorrect interpretation of particular concepts and recommendations. In this paper, brief consideration is given to definition of radiation quantities and terminology used in calibration procedures. (author)

  16. Radiometric mass flow probes for belt weighers - the state of the art and possibilities of application

    International Nuclear Information System (INIS)

    Glaeser, M.

    1986-01-01

    The setup of radiometric belt weighers is described in principle and compared with conventional ones. Fields of application are mentioned and a list is given of equipment comercially available. The comparison shows that the radiometric systems are advantageous in general, but in special cases (measuring error lower than 1%, chemical composition varies several 10%) gravimetric systems are indispensable

  17. Evaluation of an ASM1 Model Calibration Precedure on a Municipal-Industrial Wastewater Treatment Plant

    DEFF Research Database (Denmark)

    Petersen, Britta; Gernaey, Krist; Henze, Mogens

    2002-01-01

    treatment plant. In the case that was studied it was important to have a detailed description of the process dynamics, since the model was to be used as the basis for optimisation scenarios in a later phase. Therefore, a complete model calibration procedure was applied including: (1) a description......The purpose of the calibrated model determines how to approach a model calibration, e.g. which information is needed and to which level of detail the model should be calibrated. A systematic model calibration procedure was therefore defined and evaluated for a municipal–industrial wastewater...

  18. Assessment of Aero-radiometric Data of Southern Anambra Basin ...

    African Journals Online (AJOL)

    High-resolution aero-radiometric data from three radio-elements (Uranium, Potassium and Thorium) were used and processed independently to investigate the Southern Anambra basin for the prospect of producing radiogenic heat. The rock types in the study area were outlined while processing the elements in each rock ...

  19. CALIPSO IIR Version 2 Level 1b calibrated radiances: analysis and reduction of residual biases in the Northern Hemisphere

    Science.gov (United States)

    Garnier, Anne; Trémas, Thierry; Pelon, Jacques; Lee, Kam-Pui; Nobileau, Delphine; Gross-Colzy, Lydwine; Pascal, Nicolas; Ferrage, Pascale; Scott, Noëlle A.

    2018-04-01

    Version 2 of the Level 1b calibrated radiances of the Imaging Infrared Radiometer (IIR) on board the Cloud-Aerosol Lidar and Infrared Satellite Observation (CALIPSO) satellite has been released recently. This new version incorporates corrections of small but systematic seasonal calibration biases previously revealed in Version 1 data products mostly north of 30° N. These biases - of different amplitudes in the three IIR channels 8.65 µm (IIR1), 10.6 µm (IIR2), and 12.05 µm (IIR3) - were made apparent by a striping effect in images of IIR inter-channel brightness temperature differences (BTDs) and through seasonal warm biases of nighttime IIR brightness temperatures in the 30-60° N latitude range. The latter were highlighted through observed and simulated comparisons with similar channels of the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Aqua spacecraft. To characterize the calibration biases affecting Version 1 data, a semi-empirical approach is developed, which is based on the in-depth analysis of the IIR internal calibration procedure in conjunction with observations such as statistical comparisons with similar MODIS/Aqua channels. Two types of calibration biases are revealed: an equalization bias affecting part of the individual IIR images and a global bias affecting the radiometric level of each image. These biases are observed only when the temperature of the instrument increases, and they are found to be functions of elapsed time since night-to-day transition, regardless of the season. Correction coefficients of Version 1 radiances could thus be defined and implemented in the Version 2 code. As a result, the striping effect seen in Version 1 is significantly attenuated in Version 2. Systematic discrepancies between nighttime and daytime IIR-MODIS BTDs in the 30-60° N latitude range in summer are reduced from 0.2 K in Version 1 to 0.1 K in Version 2 for IIR1-MODIS29. For IIR2-MODIS31 and IIR3-MODIS32, they are reduced from 0.4 K

  20. Measurements for the energy calibration of the TANSY neutron detectors

    International Nuclear Information System (INIS)

    Drozdowicz, K.; Hoek, M.; Aronsson, D.

    1990-05-01

    The report describes measurements performed for the energy calibration of the TANSY neutron detectors (two arrays of 16 detectors each one). The calibration procedure determines four calibration parameters for each detector. Results of the calibrati