Journal articles: 'Detector radiometry'

1

Anhalt, Klaus, and Graham Machin. "Thermodynamic temperature by primary radiometry." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, no. 2064 (March 28, 2016): 20150041. http://dx.doi.org/10.1098/rsta.2015.0041.

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Above the freezing temperature of silver (1234.93 K), the International Temperature Scale of 1990 (ITS-90) gives a temperature, T 90 , in terms of a defining fixed-point blackbody and Planck's law of thermal radiation in ratio form. Alternatively, by using Planck's law directly, thermodynamic temperature can be determined by applying radiation detectors calibrated in absolute terms for their spectral responsivity. With the advent of high-quality semiconductor photodiodes and the development of high-accuracy cryogenic radiometers during the last two decades radiometric detector standards with very small uncertainties in the range of 0.01–0.02% have been developed for direct, absolute radiation thermometry with uncertainties comparable to those for the realization of the ITS-90. This article gives an overview of a number of design variants of different types of radiometer used for primary radiometry and describes their calibration. Furthermore, details and requirements regarding the experimental procedure for obtaining low uncertainty thermodynamic temperatures with these radiometers are presented, noting that such radiometers can also be used at temperatures well below the silver point. Finally, typical results obtained by these methods are reviewed.

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Sanders-Reed, John N. "Radiometry using a platinum silicide detector." Optical Engineering 36, no. 1 (January 1, 1997): 235. http://dx.doi.org/10.1117/1.601166.

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Scholze, Frank, Heike Henneken, Peter Kuschnerus,, Hans Rabus, Mathias Richter, and Gerhard Ulm. "High-accuracy detector calibration in the 3–1500 eV spectral range at the PTB radiometry laboratory." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 866–68. http://dx.doi.org/10.1107/s0909049597014076.

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State-of-the-art detector calibration in the UV/VUV and soft X-ray spectral ranges at the Physikalisch-Technische Bundesanstalt (PTB) is based on the primary detector standard SYRES, a cryogenic electrical substitution radiometer capable of measuring radiant power of a few µW. At the PTB radiometry laboratory at the synchrotron radiation facility BESSY, two dedicated beamlines are operated, providing monochromatic radiation of high spectral purity, high radiant power and tunable photon energy in the 3–1500 eV range. The spectral responsivity of detectors, e.g. photodiodes, can be measured with a relative uncertainty of about 1% by direct comparison with SYRES, as will be demonstrated for PtSi/Si and GaAsP/Au Schottky and silicon n-on-p photodiodes. The calibration of photon-counting detectors traceable to SYRES can by accomplished by exploiting the unique capability to scale the spectral photon flux over several orders of magnitude by changing the stored electron current. Calibrations of CCDs and photomultipliers are presented as examples.

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Blitzstein, William, Richard J. Mitchell, and Bruce D. Holenstein. "Estimation of detector response in optical astronomical radiometry." Applied Optics 26, no. 11 (June 1, 1987): 2055. http://dx.doi.org/10.1364/ao.26.002055.

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Rabus, H., F. Scholze, R. Thornagel, and G. Ulm. "Detector calibration at the PTB radiometry laboratory at BESSY." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 377, no. 2-3 (August 1996): 209–16. http://dx.doi.org/10.1016/0168-9002(96)00214-8.

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Ruf, C. S., S. M. Gross, and S. Misra. "RFI detection and mitigation for microwave radiometry with an agile digital detector." IEEE Transactions on Geoscience and Remote Sensing 44, no. 3 (March 2006): 694–706. http://dx.doi.org/10.1109/tgrs.2005.861411.

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Dhoska, Klodian, Helmuth Hofer, Marco López, Toomas Kübarsepp, and Stefan Kück. "Alignment position method for SPAD detector calibration and homogeneity." International Journal of Scientific Reports 1, no. 7 (November 29, 2015): 271. http://dx.doi.org/10.18203/issn.2454-2156.intjscirep20151253.

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Background: Over the last decade have seen a drastically increase of interest in the Single photon avalanche diode (SPAD) detectors applications at many variety of quantum experiments where the detection efficiency at single-photon level is required. The calibration of such detectors involves predominantly the determination of the detection efficiency.Methods: The present study was carried out at Department of Photometry and Applied Radiometry, Physikalisch-Technische Bundesanstalt (PTB), National Metrology Institute of Germany. This work is focused in a reproducible and close-to-ideal alignment position method of the SPAD detectors to the incident beam for achieving low measurement uncertainty.Results: A dominantly Gaussian profile is obtained when the diameter of the detector is smaller than the beam diameter, whereas in case then the detector is larger than the beam, a dominantly rectangular scan is obtained. The optimal position (X/Y/Z) for setting the SPAD detector correspond to Xcenter = 235.11 mm, Ycenter = 6.28 mm and Zposition = 14.6 mm. Homogeneity of the detection efficiency depends on the beam size and evaluated regions.Conclusions: The experimental set-up and experimental results needed for optimization of the SPAD detector position were described. This analysis gives important information in how to carry out the optimization of the detector position for the calibration of the SPAD and analysis of quantum detection homogeneity.

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Eyal, Ophir. "Infrared radiometry using silver halide fibers and a cooled photonic detector." Optical Engineering 33, no. 2 (February 1, 1994): 502. http://dx.doi.org/10.1117/12.153196.

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Houtz, Derek, Reza Naderpour, and Mike Schwank. "Portable L-Band Radiometer (PoLRa): Design and Characterization." Remote Sensing 12, no. 17 (August 27, 2020): 2780. http://dx.doi.org/10.3390/rs12172780.

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A low-mass and low-volume dual-polarization L-band radiometer is introduced that has applications for ground-based remote sensing or unmanned aerial vehicle (UAV)-based mapping. With prominent use aboard the ESA Soil Moisture and Ocean Salinity (SMOS) and NASA Soil Moisture Active Passive (SMAP) satellites, L-band radiometry can be used to retrieve environmental parameters, including soil moisture, sea surface salinity, snow liquid water content, snow density, vegetation optical depth, etc. The design and testing of the air-gapped patch array antenna is introduced and is shown to provide a 3-dB full power beamwidth of 37°. We present the radio-frequency (RF) front end design, which uses direct detection architecture and a square-law power detector. Calibration is performed using two internal references, including a matched resistive source (RS) at ambient temperature and an active cold source (ACS). The radio-frequency (RF) front end does not require temperature stabilization, due to characterization of the ACS noise temperature by sky measurements. The ACS characterization procedure is presented. The noise equivalent delta (Δ) temperature (NEΔT) of the radiometer is ~0.14 K at 1 s integration time. The total antenna temperature uncertainty ranges from 0.6 to 1.5 K.

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Gottwald, Alexander, Udo Kroth, Mathias Richter, Hendrik Schöppe, and Gerhard Ulm. "Ultraviolet and vacuum-ultraviolet detector-based radiometry at the Metrology Light Source." Measurement Science and Technology 21, no. 12 (October 22, 2010): 125101. http://dx.doi.org/10.1088/0957-0233/21/12/125101.

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Zhang, Peng, Naimeng Lu, Chuanrong Li, Lei Ding, Xiaobing Zheng, Xuejun Zhang, Xiuqing Hu, et al. "Development of the Chinese Space-Based Radiometric Benchmark Mission LIBRA." Remote Sensing 12, no. 14 (July 8, 2020): 2179. http://dx.doi.org/10.3390/rs12142179.

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Climate observations and their applications require measurements with high stability and low uncertainty in order to detect and assess climate variability and trends. The difficulty with space-based observations is that it is generally not possible to trace them to standard calibration references when in orbit. In order to overcome this problem, it has been proposed to deploy space-based radiometric reference systems which intercalibrate measurements from multiple satellite platforms. Such reference systems have been strongly recommended by international expert teams. This paper describes the Chinese Space-based Radiometric Benchmark (CSRB) project which has been under development since 2014. The goal of CSRB is to launch a reference-type satellite named LIBRA in around 2025. We present the roadmap for CSRB as well as requirements and specifications for LIBRA. Key technologies of the system include miniature phase-change cells providing fixed-temperature points, a cryogenic absolute radiometer, and a spontaneous parametric down-conversion detector. LIBRA will offer measurements with SI traceability for the outgoing radiation from the Earth and the incoming radiation from the Sun with high spectral resolution. The system will be realized with four payloads, i.e., the Infrared Spectrometer (IRS), the Earth-Moon Imaging Spectrometer (EMIS), the Total Solar Irradiance (TSI), and the Solar spectral Irradiance Traceable to Quantum benchmark (SITQ). An on-orbit mode for radiometric calibration traceability and a balloon-based demonstration system for LIBRA are introduced as well in the last part of this paper. As a complementary project to the Climate Absolute Radiance and Refractivity Observatory (CLARREO) and the Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS), LIBRA is expected to join the Earth observation satellite constellation and intends to contribute to space-based climate studies via publicly available data.

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Fröhlich, C., and W. Finsterle. "VIRGO Radiometry and Total Solar Irradiance 1996–2000 Revised." Symposium - International Astronomical Union 203 (2001): 105–10. http://dx.doi.org/10.1017/s0074180900218871.

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The long-term changes of the VIRGO radiometers have been re-analyzed in detail in order to resolve the puzzle of the early increase of the total solar irradiance (TSI) as observed by VIRGO. The exposure dependent changes can be described by a model which is based on a combination of an early increase of the sensitivity and a degradation with time which is modulated by the dose of solar UV radiation each detector receives. After correcting for the exposure-dependent behaviour both operational radiometers show an increase of their sensitivity which depends only on the time they are switched-on. After removing this increase the VIRGO TSI remains more or less constant during the minimum period of solar activity and reaches the solar maximum at levels comparable to the ones of former maxima.

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Hoefle, M., A. Penirschke, O. Cojocari, T. Decoopman, M. Trier, P. Piironen, M. G. Périchaud, and R. Jakoby. "89 GHz zero‐bias Schottky detector for direct detection radiometry in European satellite programme MetOp‐SG." Electronics Letters 50, no. 8 (April 2014): 606–8. http://dx.doi.org/10.1049/el.2014.0222.

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14

Smith, David, Samuel E. Hunt, Mireya Etxaluze, Dan Peters, Tim Nightingale, Jonathan Mittaz, Emma R. Woolliams, and Edward Polehampton. "Traceability of the Sentinel-3 SLSTR Level-1 Infrared Radiometric Processing." Remote Sensing 13, no. 3 (January 22, 2021): 374. http://dx.doi.org/10.3390/rs13030374.

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Providing uncertainties in satellite datasets used for Earth observation can be a daunting prospect because of the many processing stages and input data required to convert raw detector counts to calibrated radiances. The Sea and Land Surface Temperature Radiometer (SLSTR) was designed to provide measurements of the Earth’s surface for operational and climate applications. In this paper the authors describe the traceability chain and derivation of uncertainty estimates for the thermal infrared channel radiometry. Starting from the instrument model, the contributing input quantities are identified to build up an uncertainty effects tree. The characterisation of each input effect is described, and uncertainty estimates provided which are used to derive the combined uncertainties as a function of scene temperature. The SLSTR Level-1 data products provide uncertainty estimates for fully random effects (noise) and systematic effects that can be mapped for each image pixel, examples of which are shown.

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15

Majaron, B., M. Milanič, B. Choi, and J. S. Nelson. "Selecting optimal detector for temperature profiling in human skin using pulsed photothermal radiometry." Journal de Physique IV (Proceedings) 125 (June 2005): 737–39. http://dx.doi.org/10.1051/jp4:2005125169.

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Jokela, Kari, Lasse Ylianttila, Reijo Visuri, Kirsti Leszczynski, Petri Kärhä, and Erkki Ikonen. "Intercomparison of lamp and detector-based UV-irradiance scales for solar UV radiometry." Journal of Geophysical Research: Atmospheres 105, no. D4 (February 1, 2000): 4821–27. http://dx.doi.org/10.1029/1999jd900398.

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Storch, T., H. P. Honold, K. Alonso, M. Pato, M. Mücke, P. Basili, S. Chabrillat, and S. Fischer. "STATUS OF THE IMAGING SPECTROSCOPY MISSION ENMAP WITH RADIOMETRIC CALIBRATION AND CORRECTION." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences V-1-2020 (August 3, 2020): 41–47. http://dx.doi.org/10.5194/isprs-annals-v-1-2020-41-2020.

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Abstract. The high-resolution imaging spectroscopy remote sensing mission EnMAP (Environmental Mapping and Analysis Program, enmap.org) covers the spectral range from 420 nm to 2450 nm with a spectral sampling distance varying between 4.8 nm and 12.0 nm comprising 262 spectral bands. We focus on the planned framework concerning radiometry. The expected signal-to-noise ratio at reference radiance level is 500:1 at 495 nm and 150:1 at 2200 nm. The radiometric resolution is 14 bits and an absolute radiometric accuracy of better than 5% is achieved. Radiometric calibration is based on Sun calibration measurements with a fullaperture diffusor for absolute calibration. In addition, relative calibration monitors the instrument during the complete mission lifetime based on an integrating sphere (on the satellite). The fully-automatic on-ground image processing chain considers the derived radiometric calibration coefficients in the radiometric correction which is followed by the orthorectification and atmospheric compensation. Each of the two 2-dimensional detector arrays of the prism-based pushbroom dual-spectrometer works in a dual-gain configuration to cover the complete dynamic range. EnMAP will acquire 30 km in the across-track direction with a ground sampling distance of 30 m and the across-track tilt capability of 30° will enable a target revisit time of less than 4 days. The launch is scheduled for 2021. The high-quality products will be freely available to international scientific users for measuring and analysing diagnostic parameters which describe vital processes on the Earth’s surface.

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Van Nieuwkerk, H. J., A. C. Veltkamp, H. A. Das, U. A. Th Brinkman, and R. W. Frei. "Characterization of a β-detector for on-line radiometry in high performance liquid chromatography." Journal of Radioanalytical and Nuclear Chemistry 100, no. 1 (July 1986): 165–76. http://dx.doi.org/10.1007/bf02036510.

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Cormack, Douglas, Neil Hurford, and David Tookey. "REMOTE SENSING TECHNIQUES FOR DETECTING OIL SLICKS AT SEA—A REVIEW OF WORK CARRIED OUT IN THE UNITED KINGDOM." International Oil Spill Conference Proceedings 1987, no. 1 (April 1, 1987): 95–100. http://dx.doi.org/10.7901/2169-3358-1987-1-95.

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ABSTRACT The U.K. Department of Transport has equipped a light aircraft with a remote sensing system. The capabilities of the sensors for detecting oil slicks have been evaluated and the aircraft is now being used to carry out surveillance patrols. A detailed evaluation has been carried out into the feasibility of using microwave radiometry to supply more detailed information about oil slick thickness. The results showed that such a detector should only be used in conjunction with existing IR and UV sensors.

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Salffner, K., T. Dönsberg, G. Porrovecchio, M. Smid, K. Nield, and S. Nevas. "Characterization of a room temperature predictable quantum efficient detector for applications in radiometry and photometry." Metrologia 55, no. 5 (July 27, 2018): 654–61. http://dx.doi.org/10.1088/1681-7575/aad19d.

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Sun, Lei, Wei Bing Wang, and Xiao Yong Fang. "A Novel Structure of Thermopile Infrared Detector with High Responsivity Based on CMOS Process." Applied Mechanics and Materials 271-272 (December 2012): 381–85. http://dx.doi.org/10.4028/www.scientific.net/amm.271-272.381.

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Superscript textThermopile-type Infrared detector is more and more popular in many fields, including infrared spectroscopy, radiometry, security systems and many consumer products. This paper reports a novel n-poly/p-poly thermopile suspension structure with four pairs of thermopiles that compatible with Complementary Metal-Oxide Semiconductor (CMOS) technology and its fill factor is larger than 90%. No additional material is needed to enhance infrared absorption since the passivation layer provided by the CMOS process is sufficient for certain infrared spectral bands. With the selected material parameters the optimal structure parameters are obtained after simulation. Through the theoretic calculation, this novel IR detector has good properties of high responsivity (larger than 1000V/W) and detectivity (larger than 1×108cm Hz1/2W-1) and low response time (shorter than 30ms).

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Török, S., J. Osán, B. Beckhoff, and G. Ulm. "Ultratrace speciation of nitrogen compounds in aerosols collected on silicon wafer surfaces by means of TXRF-NEXAFS." Powder Diffraction 19, no. 1 (March 2004): 81–86. http://dx.doi.org/10.1154/1.1649327.

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Total reflection X-ray fluorescence analysis (TXRF) using monochromatized undulator radiation in the PTB radiometry laboratory at the synchrotron radiation facility BESSY II has been employed to investigate the chemical state of nitrogen compounds in aerosols. The aerosol samples of different size fractions were deposited on silicon wafer surfaces in a May impactor. Using a thin window Si(Li) detector, TXRF detection limits for nitrogen are in the upper fg and lower pg range. Taking advantage of the tunability of monochromatized undulator radiation, the near edge X-ray absorption fine structure (NEXAFS) could be combined with TXRF analysis, allowing for the speciation of the aerosols at the nitrogen K absorption edge. Such low detection limits enable an analysis of aerosol samples taken in 10 min with acceptable accuracy. Applicability of the technique to real aerosol samples has been used to compare nitrogen oxidation state in suburban and rural aerosols

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Beckhoff, B., R. Klein, M. Krumrey, F. Scholze, R. Thornagel, and G. Ulm. "X-ray detector calibration in the PTB radiometry laboratory at the electron storage ring BESSY II." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 444, no. 1-2 (April 2000): 480–83. http://dx.doi.org/10.1016/s0168-9002(99)01427-8.

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Böttger, U., K. Beier, B. Biering, C. Müller, M. Peichl, and W. Spyra. ""easyMine" – realistic and systematic mine detection simulation tooltion." Advances in Radio Science 2 (May 27, 2005): 237–39. http://dx.doi.org/10.5194/ars-2-237-2004.

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Abstract. Mine detection is to date mainly performed with metal detectors, although new methods for UXO detection are explored worldwide. The main problem for the mine detection to date is, that there exist some ideas of which sensor combinations could yield a high score, but until now there is no systematic analysis of mine detection methods together with realistic environmental conditions to conclude on a physically and technically optimized sensor combination. This gap will be removed by a project “easyMine" (Realistic and systematic Mine Detection Simulation Tool) which will result in a simulation tool for optimizing land mine detection in a realistic mine field. The project idea for this software tool is presented, that will simulate the closed chain of mine detection, including the mine in its natural environment, the sensor, the evaluation and application of the measurements by an user. The tool will be modularly designed. Each chain link will be an independent, exchangeable sub- module and will describe a stand alone part of the whole mine detection procedure. The advantage of the tool will be the evaluation of very different kinds of sensor combinations in relation of their real potential for mine detection. Three detection methods (metal detector, GPR and imaging IR-radiometry) will be explained to be introduced into the easyMine software tool in a first step. An actual example for land mine detection problem will be presented and approaches for solutions with easyMine will be shown.

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Stentoumis, C., E. Protopapadakis, A. Doulamis, and N. Doulamis. "A HOLISTIC APPROACH FOR INSPECTION OF CIVIL INFRASTRUCTURES BASED ON COMPUTER VISION TECHNIQUES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B5 (June 15, 2016): 131–38. http://dx.doi.org/10.5194/isprsarchives-xli-b5-131-2016.

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In this work, it is examined the 2D recognition and 3D modelling of concrete tunnel cracks, through visual cues. At the time being, the structural integrity inspection of large-scale infrastructures is mainly performed through visual observations by human inspectors, who identify structural defects, rate them and, then, categorize their severity. The described approach targets at minimum human intervention, for autonomous inspection of civil infrastructures. The shortfalls of existing approaches in crack assessment are being addressed by proposing a novel detection scheme. Although efforts have been made in the field, synergies among proposed techniques are still missing. The holistic approach of this paper exploits the state of the art techniques of pattern recognition and stereo-matching, in order to build accurate 3D crack models. The innovation lies in the hybrid approach for the CNN detector initialization, and the use of the modified census transformation for stereo matching along with a binary fusion of two state-of-the-art optimization schemes. The described approach manages to deal with images of harsh radiometry, along with severe radiometric differences in the stereo pair. The effectiveness of this workflow is evaluated on a real dataset gathered in highway and railway tunnels. What is promising is that the computer vision workflow described in this work can be transferred, with adaptations of course, to other infrastructure such as pipelines, bridges and large industrial facilities that are in the need of continuous state assessment during their operational life cycle.

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Stentoumis, C., E. Protopapadakis, A. Doulamis, and N. Doulamis. "A HOLISTIC APPROACH FOR INSPECTION OF CIVIL INFRASTRUCTURES BASED ON COMPUTER VISION TECHNIQUES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B5 (June 15, 2016): 131–38. http://dx.doi.org/10.5194/isprs-archives-xli-b5-131-2016.

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In this work, it is examined the 2D recognition and 3D modelling of concrete tunnel cracks, through visual cues. At the time being, the structural integrity inspection of large-scale infrastructures is mainly performed through visual observations by human inspectors, who identify structural defects, rate them and, then, categorize their severity. The described approach targets at minimum human intervention, for autonomous inspection of civil infrastructures. The shortfalls of existing approaches in crack assessment are being addressed by proposing a novel detection scheme. Although efforts have been made in the field, synergies among proposed techniques are still missing. The holistic approach of this paper exploits the state of the art techniques of pattern recognition and stereo-matching, in order to build accurate 3D crack models. The innovation lies in the hybrid approach for the CNN detector initialization, and the use of the modified census transformation for stereo matching along with a binary fusion of two state-of-the-art optimization schemes. The described approach manages to deal with images of harsh radiometry, along with severe radiometric differences in the stereo pair. The effectiveness of this workflow is evaluated on a real dataset gathered in highway and railway tunnels. What is promising is that the computer vision workflow described in this work can be transferred, with adaptations of course, to other infrastructure such as pipelines, bridges and large industrial facilities that are in the need of continuous state assessment during their operational life cycle.

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Martan, J., O. Hervé, and V. Lang. "Two-detector measurement system of pulse photothermal radiometry for the investigation of the thermal properties of thin films." Journal of Applied Physics 102, no. 6 (September 15, 2007): 064903. http://dx.doi.org/10.1063/1.2778642.

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Viswanathan, S., S. Chandrasekaran, and B. Venkatraman. "Nondestructive Evaluation of Hot Cell Liner Bricks by Radiometric Testing." Materials Evaluation 79, no. 2 (February 1, 2021): 106–12. http://dx.doi.org/10.32548/2021.me-04118.

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In nuclear facilities, controlling radiation exposure to operating personnel within limits specified by the regulatory body is mandatory; it is required to maintain the radiation level in occupancy areas “as low as reasonably achievable” (ALARA). Highly radioactive sources, materials, and components are enclosed in concrete cells, known as hot cells. Masterslave manipulators (MSMs) are used for the remote handling of equipment located in the hot cell. The MSM is fitted into the hot cell with liner bricks made of lead. The liner brick assembly is a lead poured structure with a steel lining, which gives an effective longitudinal shielding thickness of 250 mm when fitted into the cell with the MSM. Conventional nondestructive testing (NDT) methods such as radiographic testing (RT) and ultrasonic testing have limitations with respect to thickness and coarse-grained structures. Gamma radiometry, which is based on the principle of differential attenuation of radiation, has been developed and adopted in similar applications (Suresh Kumar et al. 2011). It is a challenge to optimize the gamma source strength required for testing, taking into account the sensitivity of the radiation detector and shielding thickness of the component under testing. This paper focuses on the choice of the radiation source and its strength, the experimental approach, the theoretical modeling undertaken for dose-rate estimation, and the actual measurement of radiation during the radiometric testing of MSM liner bricks.

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Sikora, Tomasz, Karolina Morawska, and Wiesław Lisowski. "A Mobile Device for Monitoring the Biological Purity of Air and Liquid Samples." Sensors 21, no. 10 (May 20, 2021): 3570. http://dx.doi.org/10.3390/s21103570.

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A detector for identifying potential bacterial hazards in the air was designed and created in the Military Institute of Chemistry and Radiometry in the framework of the project FLORABO. The presence of fungi and bacteria in the air can affect the health of people in a given room. The need to control the amount of microorganisms, both in terms of quantity and quality, applies to both hospitals and offices. The device is based on the fluorescence spectroscopy analysis of the sample and then these results were compared to the resulting spectrogram database, which includes the standard curves obtained in the laboratory for selected bacteria. The measurements provide information about the presence, the type, and the approximate concentration of bacteria in the sample. The spectra were collected at different excitation wavelengths, and the waveforms are specific for each of the strains. It also takes under analysis the signal intensities of the different spectra (not only shape a maximum of the peak) so that the concentration of bacteria in the sample being tested can be determined. The device was tested in the laboratory with concentrations ranging from 10 to 108 cells/mL. Additionally, the detector can distinguish between the vegetative forms of spores of the bacteria.

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Pascual, Juan Pablo, Beatriz Aja, Enrique Villa, Jose Vicente Terán, Luisa de la Fuente, and Eduardo Artal. "Performance Assessment of W-Band Radiometers: Direct versus Heterodyne Detections." Electronics 10, no. 18 (September 21, 2021): 2317. http://dx.doi.org/10.3390/electronics10182317.

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W-Band radiometers using intermediate frequency down-conversion (super-heterodyne) and direct detection are compared. Both receivers consist of two W-band low noise amplifiers and an 80-to-101 GHz filter, which conforms to the reception frequency band, in the front-end module. The back-end module of the first receiver comprises a subharmonic mixer, intermediate frequency (IF) amplification and a square-law detector. For direct detection, a W-Band detector replaces the mixer and the intermediate frequency detection stages. The performance of the whole receivers has been simulated requiring special techniques, based on data from the experimental characterization of each subsystem. In the super-heterodyne implementation a local oscillator at 27.1 GHz (with 8 dBm) with a x3 frequency multiplier is used, exhibiting an overall conversion gain around 48 dB, a noise figure around 4 dB, and an effective bandwidth over 10 GHz. In the direct detection scheme, slightly better noise performance is obtained, with a wider bandwidth, around 20 GHz, since there is no IF bandwidth limitation (~15 GHz), and even using the same 80-to-101 GHz filter, the detector can operate through the whole W-band. Moreover, W-band detector has higher sensitivity than the IF detector, increasing slightly the gain. In both cases, the receiver performance is characterized when a broadband noise input signal is applied. The radiometer characteristics have been obtained working as a total power radiometer and as a Dicke radiometer when an optical chopper is used to modulate the incoming signal. Combining this particular super-heterodyne or direct detection topologies and total power or Dicke modes of operation, four different cases are compared and discussed, achieving similar sensitivities, but better performances in terms of equivalent bandwidth and noise for the direct detection radiometer. It should be noted that this conclusion comes from a particular set of components, which we could consider as typical, but we cannot exclude other conclusions for different components, particularly for different mixers and detectors.

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RADZHAPOV, SALI, RUSTAM RAKHIMOV, BEGJAN RADZHAPOV, and MARS ZUFAROV. "CALCULATION OF STAGES OF THE TECHNOLOGICAL PROCESS OF MANUFACTURE OF PPD DETECTORS USING COMPUTER MATHEMATICAL MODELING AND PRODUCTION OF ALPHA RADIOMETER ON THEIR BASIS." Computational nanotechnology 7, no. 2 (June 30, 2020): 21–28. http://dx.doi.org/10.33693/2313-223x-2020-7-2-21-28.

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The article describes the developed radiometer for Express measurement of alpha radiation of radioactive elements based on a large-diameter silicon detector. The main element of the PPD detector is made using computer mathematical modeling of all stages of the technological process of manufacturing detectors, taking into account at each stage the degree of influence of the properties of the initial silicon on the electrophysical and radiometric characteristics of the detector. Detectors are manufactured for certain types of devices. The developed radiometer is designed to measure alpha radiation of natural isotopes (238U, 234U, 232Th, 226Ra, 222Rn, 218Po, 214Bi, etc.) in various environments. It also shows the principle of operation of the device, provides a block diagram of the measuring complex, describes the electronic components of the radiometer, as well as the block diagram. Signal transformations (spectrum transfer, filtering, accumulation) are implemented programmatically on the basis of a digital processing module. The device can detect the presence of specific elements in various environments, as well as protect people from the harmful effects of adverse radiation and can be used both in the field and stationary.

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32

Whatmore, Roger W. "Recent Advances in Pyroelectric Ceramics and Thin Films for Applications in Uncooled Infra-Red Sensor Arrays." Advances in Science and Technology 45 (October 2006): 2503–13. http://dx.doi.org/10.4028/www.scientific.net/ast.45.2503.

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Pyroelectric infra-red detector arrays provide an attractive solution to the problem of collecting spatial information on the IR distribution in a scene. They have the property that they are only sensitive to changes in the IR flux. This means that they are particularly-well suited to the monitoring of movements of people in applications such as retail outlets and in safety and healthcare applications. The applications of low cost arrays with limited (few hundred elements) for people sensing and imaging radiometry will be illustrated. The performances and costs of uncooled pyroelectric arrays are ultimately driven by the materials used. For this reason, continuous improvements in materials technology are important. In the area of bulk ceramics, it is possible to obtain significant improvements in both production costs and performance though the use of tape-cast, functionally-gradient materials. The use of directly-deposited ferroelectric thin films on silicon ASIC’s is offering considerable potential for low cost high performance pyroelectric arrays. The challenges involved in developing such materials will be discussed.

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33

Palchetti, L., G. Bianchini, B. Carli, U. Cortesi, and S. Del Bianco. "Measurement of the water vapour vertical profile and of the Earth's outgoing far infrared flux." Atmospheric Chemistry and Physics 8, no. 11 (June 6, 2008): 2885–94. http://dx.doi.org/10.5194/acp-8-2885-2008.

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Abstract. Our understanding of global warming depends on the accuracy with which the atmospheric components that modulate the Earth's radiation budget are known. Many uncertainties still exist as regards the radiative effect of water in the different spectral regions, among which is the far infrared, where very few observations have been made. An assessment is shown of the atmospheric outgoing flux obtained from a balloon-borne platform with wideband spectrally-resolved nadir measurements at the top of the atmosphere over the full spectral range, from 100 to 1400 cm−1, made by a Fourier transform spectrometer with uncooled detectors. From these measurements, we retrieved 15 pieces of information regarding water vapour and temperature profiles and surface temperature, with a major improvement in our knowledge of water vapour in the upper troposphere. The retrieved atmospheric state made it possible to calculate the emitted radiance also at frequencies and zenith angles that have not been observed and to determine the outgoing spectral radiation flux. This proves that spectrally resolved observations can be used to derive accurate information on the integrated flux. While the retrieved temperature was in agreement with ECMWF analysis, the retrieved water vapour profile differed significantly; depending on the time and the location, the derived flux in the far infrared (20–600 cm−1) differed by 2–3.5 W/m2 from that calculated using ECMWF. The error with which the far infrared flux is determined by REFIR-PAD is about 0.4 W/m2 and is caused mainly by calibration uncertainties, while detector noise has a negligible effect. This proves that uncooled detectors are adequate for top-of-the-atmosphere radiometry.

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Querol, J., A. Perez, and A. Camps. "A Review of RFI Mitigation Techniques in Microwave Radiometry." Remote Sensing 11, no. 24 (December 17, 2019): 3042. http://dx.doi.org/10.3390/rs11243042.

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Radio frequency interference (RFI) is a well-known problem in microwave radiometry (MWR). Any undesired signal overlapping the MWR protected frequency bands introduces a bias in the measurements, which can corrupt the retrieved geophysical parameters. This paper presents a literature review of RFI detection and mitigation techniques for microwave radiometry from space. The reviewed techniques are divided between real aperture and aperture synthesis. A discussion and assessment of the application of RFI mitigation techniques is presented for each type of radiometer.

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35

Palchetti, L., G. Bianchini, B. Carli, U. Cortesi, and S. Del Bianco. "Measurement of the water vapour vertical profile and of the Earth's outgoing far infrared flux." Atmospheric Chemistry and Physics Discussions 7, no. 6 (December 10, 2007): 17741–67. http://dx.doi.org/10.5194/acpd-7-17741-2007.

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Abstract. Our understanding of global warming depends on the accuracy with which the atmospheric components that modulate the Earth's radiation budget are known. Many uncertainties still exist on the radiative effect of water in the different spectral regions, among which the far infrared where few observations have been made. An assessment is shown of the atmospheric outgoing flux obtained from a balloon-borne platform with wideband spectrally resolved nadir measurements at the top-of-atmosphere over the full spectral range, including the far infrared, from 100 to 1400 cm−1, made by a Fourier transform spectrometer with uncooled detectors. From these measurements, we retrieve 15 pieces of information about water vapour and temperature profiles, and surface temperature, with a precision of 5% for the mean water vapour profile and a major improvement of the upper troposphere-lower stratosphere knowledge. The retrieved atmospheric state makes it possible to calculate the emitted radiance as a function of the zenith angle and to determine the outgoing radiation flux, proving that spectrally resolved observations can be used to derive accurate information on the integrated flux. While the retrieved temperature is in good agreement with ECMWF analysis, the retrieved water vapour profile differs significantly, and, depending on time and location, the derived flux differs in the far infrared (0–600 cm−1) from that derived from ECMWF by 2–3.5 W/m2±0.4 W/m2. The observed discrepancy is larger than current estimates of radiative forcing due to CO2 increases since pre-industrial time. The error with which the flux is determined is caused mainly by calibration uncertainties while detector noise has a negligible effect, proving that uncooled detectors are adequate for top of the atmosphere radiometry.

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36

Guo, Tianshu, Xi Guo, Cheng Zhang, Donghao Han, Lijie Niu, Hao Liu, and Ji Wu. "A Time-Domain Simulation System of MICAP L-Band Radiometer for Pre-Launch RFI Processing Study." Remote Sensing 13, no. 16 (August 14, 2021): 3230. http://dx.doi.org/10.3390/rs13163230.

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Microwave Imager Combined Active and Passive (MICAP), which is a package of active and passive microwave instruments including L/C/K-band radiometers and L-band scatterometer, has been approved to be taken onbord the Chinese Ocean Salinity Mission. The L-band one-dimensional synthetic aperture radiometer (L-Rad) is the key part of MICAP to measure sea surface salinity (SSS). Since radio frequency interference (RFI) is reported as a serious threat to L-band radiometry, the RFI detection and mitigation techniques must be carefully designed before launch. However, these techniques need to be developed based on the knowledge of how RFI affects complex correlation, visibility function, and reconstructed brightness temperature. This paper presents a time-domain signal modeling method for the simulation of interferometric measurement under RFI’s presences, and a simulation system for L-Rad is established accordingly. Several RFI cases are simulated with different RFI types, parameters, and positions; and the RFI characteristics upon L-Rad’s measurement are discussed. The proposed simulation system will be further dedicated to the design of RFI processing strategy onboard MICAP.

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37

Pekker, Sándor, and Edward M. Eyring. "Electrothermal Radiometric Detection of the Semiconductor-to-Metal-Phase Transition in Single-Crystal (TaSe4)2I." Applied Spectroscopy 41, no. 2 (February 1987): 260–64. http://dx.doi.org/10.1366/000370287774986912.

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Electrothermal radiometry, a new radiometric technique for investigating phase transitions in semiconductors and metals, is described. Single crystals of (TaSe4)2I are heated by electric current pulses, and the thermal radiation of the samples is detected. The dependence of the electrothermal radiometry signal on the frequency and amplitude of the current pulses and on the temperature is discussed. The signal intensity is inversely proportional to the frequency. The static component of the temperature at the surface is obtained from the dependence on the current intensity. The temperature dependence is mostly determined by the change of the resistivity of the sample.

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38

Radzhapov, Sali Ashirovich, Rustam Khakimovich Rakhimov, Begjan Salievich Radzhapov, and Mars Achmedovich Zufarov. "SILICON-LITHIUM ΔE-DETECTORS OF ALPHA-RADIATION TO THE RADIOMETER." Computational nanotechnology 6, no. 2 (June 30, 2019): 157–59. http://dx.doi.org/10.33693/2313-223x-2019-6-2-157-159.

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The paper presents the optimization of the manufacturing technology of silicon-lithium Δ Ε -detectors of large size, as well as some research data on the radiometric characteristics of silicon-lithium Δ Ε -detectors with a diameter of 4-8 cm and a radiometer based on them.

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39

Buckley, Courtney D., Robbie E. Hood, and Frank J. LaFontaine. "Application of Airborne Passive Microwave Observations for Monitoring Inland Flooding Caused by Tropical Cyclones." Journal of Atmospheric and Oceanic Technology 26, no. 10 (October 1, 2009): 2051–70. http://dx.doi.org/10.1175/2009jtecha1273.1.

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Abstract Inland flooding from tropical cyclones is a significant factor in storm-related deaths in the United States and other countries, with the majority of tropical cyclone fatalities recorded in the United States resulting from freshwater flooding. Information collected during National Aeronautics and Space Administration (NASA) tropical cyclone field experiments suggests that surface water and flooding can be detected and therefore monitored at a greater spatial resolution by using passive microwave airborne radiometers than by using satellite sensors. The 10.7-GHz frequency of the NASA Advanced Microwave Precipitation Radiometer (AMPR) has demonstrated high-resolution detection of anomalous surface water and flooding in numerous situations. In this study, an analysis of three cases is conducted utilizing satellite and airborne radiometer data. Data from the 1998 Third Convection and Moisture Experiment (CAMEX-3) are utilized to detect surface water during the landfalling Hurricane Georges in both the Dominican Republic and Louisiana. Another case studied was the landfalling Tropical Storm Gert in eastern Mexico during the Tropical Cloud Systems and Processes (TCSP) experiment in 2005. AMPR data are compared to topographic data and vegetation indices to evaluate the significance of the surface water signature visible in the 10.7-GHz information. The results illustrate the AMPR’s utility in monitoring surface water that current satellite-based passive microwave radiometers are unable to monitor because of their coarser resolutions. This suggests the benefit of a radiometer with observing frequencies less than 11 GHz deployed on a manned aircraft or unmanned aircraft system to provide early detection in real time of expanding surface water or flooding conditions.

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40

Denaro, L. G., and C. H. Lin. "HYBRID CANONICAL CORRELATION ANALYSIS AND REGRESSION FOR RADIOMETRIC NORMALIZATION OF CROSS-SENSOR SATELLITE IMAGES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W19 (December 23, 2019): 181–83. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w19-181-2019.

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Abstract. Relative radiometric normalization (RRN) minimizes radiometric differences among images caused by inconsistencies of acquisition condition. In this study, a cross-sensor RRN method is proposed for optical satellite images from Landsat 8 OLI (L8) and Landsat 7 ETM+ (L7) sensors. The data from these two sensors have different pixel depths. Therefore, a rescaling on the radiometry resolution is performed in the preprocessing. Then, multivariate alteration detection (MAD) based on kernel canonical correlation analysis (KCCA) is adopted, which is called KCCA-based MAD, to select pseudo-invariant features (PIFs). The process of RRN is performed by using polynomial regression with Gaussian weighted regression. In experiments, qualitative and quantitative analyses on images from different sensors are conducted. The experimental result demonstrates the superiority of the proposed nonlinear transformation, in terms of regression quality and radiometric consistency, compared with RRN using linear regression.

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41

Grigoryev, A. N. "Alpha-, beta-, gamma-radiometric measurements using semiconductor detectors." Functional materials 21, no. 3 (September 30, 2014): 352–55. http://dx.doi.org/10.15407/fm21.03.352.

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42

Karanasiou, Irene. "Imaging of Conductivity Changes of Excitable Tissues Based on Focused Passive Microwave." Open Biomedical Engineering Journal 9, no. 1 (July 31, 2015): 138–45. http://dx.doi.org/10.2174/1874120701509010138.

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Aims:Modeling of ionic distribution fluctuations of excitable tissues based on data elicited using focused microwave radiometry.Methodology:Focused Microwave Radiometry implemented to carry out measurements of in depth body temperature distributions, may provide the capability of sensing local electrical conductivity fluctuations during the cycle of actions potentials in the case of brain excitable cell clusters. An analog beamformer consisting of a conductive inner-surface ellipsoidal cavity is used to focus the chaotic-black body radiation emerging from human tissues by providing convergence of the electromagnetic energy from one focus area where the phantom or subject is placed, to the other where the antennas of sensitive radiometric receivers are positioned. During the past 10 years numerous phantom, animal and human volunteer experiments have been performed with the focused radiometry imaging system. The results show that the detected changes of the output radiometric voltage are attributed to temperature and/or conductivity changes that occur locally concentrated at the areas of interest under measurement. Theoretical and experimental studies are continuously carried out at various frequency bands in conjunction with the use of matching materials placed around the human head or phantom to improve focusing and detection depth. It seems that the manipulation of the focusing area in the tissue in terms of detection depth and spatial resolution is feasible depending on the suitable combination of operation frequencies and matching material. In this paper, theoretical analysis of ion charge diffusion during the cycle of action potentials, propagating along the axons in case of measurements of specific cortical regions is presented. The ion charge diffusion modeling is based on electromagnetic diffusion analogies in the effort to explain the observed experimental results obtained under various psychophysiological conditions in the case of human volunteer measurements.Results:By implementing an analysis based on the continuity equations of ionic charges it is concluded that the microwave radiometry output voltage is not affected by the temporal and spatial average fluctuations of Na+, K+, and Cl-ions of neural cell axons.Conclusion:The analysis of conductivity fluctuations in the central neural system in conjunction with the electromagnetic analysis of the system, leads to the interpretation of the previously acquired experimental data. The application of this technique with other brain functional mapping methods, may provide complementary knowledge to the understanding of the functional organization of psychophysiological processes.

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43

Friedrich, R., J. Fischer, and M. Stock. "Accurate calibration of filter radiometers against a cryogenic radiometer using a trap detector." Metrologia 32, no. 6 (December 1, 1995): 509–13. http://dx.doi.org/10.1088/0026-1394/32/6/22.

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44

Jende, P., M. Peter, M. Gerke, and G. Vosselman. "ADVANCED TIE FEATURE MATCHING FOR THE REGISTRATION OF MOBILE MAPPING IMAGING DATA AND AERIAL IMAGERY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (June 3, 2016): 617–23. http://dx.doi.org/10.5194/isprs-archives-xli-b1-617-2016.

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Mobile Mapping’s ability to acquire high-resolution ground data is opposing unreliable localisation capabilities of satellite-based positioning systems in urban areas. Buildings shape canyons impeding a direct line-of-sight to navigation satellites resulting in a deficiency to accurately estimate the mobile platform’s position. Consequently, acquired data products’ positioning quality is considerably diminished. This issue has been widely addressed in the literature and research projects. However, a consistent compliance of sub-decimetre accuracy as well as a correction of errors in height remain unsolved. We propose a novel approach to enhance Mobile Mapping (MM) image orientation based on the utilisation of highly accurate orientation parameters derived from aerial imagery. In addition to that, the diminished exterior orientation parameters of the MM platform will be utilised as they enable the application of accurate matching techniques needed to derive reliable tie information. This tie information will then be used within an adjustment solution to correct affected MM data. This paper presents an advanced feature matching procedure as a prerequisite to the aforementioned orientation update. MM data is ortho-projected to gain a higher resemblance to aerial nadir data simplifying the images’ geometry for matching. By utilising MM exterior orientation parameters, search windows may be used in conjunction with a selective keypoint detection and template matching. Originating from different sensor systems, however, difficulties arise with respect to changes in illumination, radiometry and a different original perspective. To respond to these challenges for feature detection, the procedure relies on detecting keypoints in only one image. Initial tests indicate a considerable improvement in comparison to classic detector/descriptor approaches in this particular matching scenario. This method leads to a significant reduction of outliers due to the limited availability of putative matches and the utilisation of templates instead of feature descriptors. In our experiments discussed in this paper, typical urban scenes have been used for evaluating the proposed method. Even though no additional outlier removal techniques have been used, our method yields almost 90% of correct correspondences. However, repetitive image patterns may still induce ambiguities which cannot be fully averted by this technique. Hence and besides, possible advancements will be briefly presented.

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45

Durak, M. "Spatial non-uniformity analyses of radiometric detectors to identify suited transfer standards for optical radiometry." European Physical Journal Applied Physics 32, no. 3 (December 2005): 193–97. http://dx.doi.org/10.1051/epjap:2005092.

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46

Lu, Xuan, Li Wu, Ze Long Xiao, and Jian Zhong Xu. "Ranging Technique Based on Conically Scanned Single Pixel Millimeter Wave Radiometer." International Journal of Engineering Research in Africa 12 (June 2014): 43–52. http://dx.doi.org/10.4028/www.scientific.net/jera.12.43.

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Passive millimeter wave detection offers great advantages of covertness and anti-interference in surveillance and concealed weapon detection but suffers from disabilities of distance measurement. Based on the conically scanned single pixel millimeter wave radiometer, this paper presents a ranging method via dual-measurement utilizing the relation between the solid angle of the object and its distance from antenna. Both one-dimensional and two-dimensional detections are considered. For one-dimensional detection, the relation between the solid angle of the object and the range is reflected by the pulse width of the radiometer output, and the pulse widths of the radiometer output in two measurements could be extracted by derivative or threshold method. Then the range is calculated since it is inversely proportional to the pulse width, which is demonstrated in simulation. For two-dimensional imaging, a scale extracting algorithm is developed to search the scale between the object sizes of bi-measured images. Experiments are performed using a 94.5GHz total-power radiometer mounted on conically scanning platform. The obtained radiometric images are processed by the developed algorithm and the results indicated that both the scale extracting algorithm and the ranging method are effective and practical.

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47

Randolph, Kaylan, Heidi M. Dierssen, Alejandro Cifuentes-Lorenzen, William M. Balch, Edward C. Monahan, Christopher J. Zappa, Dave T. Drapeau, and Bruce Bowler. "Novel Methods for Optically Measuring Whitecaps under Natural Wave-Breaking Conditions in the Southern Ocean." Journal of Atmospheric and Oceanic Technology 34, no. 3 (March 2017): 533–54. http://dx.doi.org/10.1175/jtech-d-16-0086.1.

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AbstractTraditional methods for measuring whitecap coverage using digital video systems mounted to measure a large footprint can miss features that do not produce a high enough contrast to the background. Here, a method for accurately measuring the fractional coverage, intensity, and decay time of whitecaps using above-water radiometry is presented. The methodology was developed using data collected in the Southern Ocean under a wide range of wind and wave conditions. Whitecap quantities were obtained by employing a magnitude threshold based on the interquartile range of the radiance or reflectance signal from a single channel. Breaking intensity and decay time were produced from the integration of and the exponential fit to radiance or reflectance over the lifetime of the whitecap. When using the lowest magnitude threshold possible, radiometric fractional whitecap coverage retrievals were consistently higher than fractional coverage from high-resolution digital images, perhaps because the radiometer captures more of the decaying bubble plume area that is difficult to detect with photography. Radiometrically obtained whitecap measurements are presented in the context of concurrently measured meteorological (e.g., wind speed) and oceanographic (e.g., wave) data. The optimal fit of the radiometrically estimated whitecap coverage to the instantaneous wind speed, determined using robust linear least squares, showed a near-cubic dependence. Increasing the magnitude threshold for whitecap detection from 2 to 4 times the interquartile range produced a wind speed–whitecap relationship most comparable to the concurrently collected fractional coverage from digital imagery and previously published wind speed–whitecap parameterizations.

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48

Kanstad, Svein Otto, and Per-Erik Nordal. "Experimental aspects of photothermal radiometry." Canadian Journal of Physics 64, no. 9 (September 1, 1986): 1155–64. http://dx.doi.org/10.1139/p86-201.

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In photothermal radiometry (PTR), the thermal response of a given sample to time-varying illumination is detected via concomitant thermal radiation emanating from the irradiated region, to obtain spectral, structural, and other types of information about the sample. Excitation of the thermal response may be achieved in one of several different pulsing modes, with detection of the thermal reradiation over a wide range of wavelength bands, power levels, and frequencies. To fully exploit the power and versatility of PTR, therefore, it is necessary to choose judiciously the experimental conditions and equipment appropriate in each analytic situation. We discuss general physical aspects of PTR, emphasizing fundamental principles and methodology related to the detection of thermal reradiation. As will be shown, PTR lends itself well to explicit numerical analysis, greatly aiding the design and interpretation of experiments. Particular features relating to the investigation of high-temperature objects will be discussed. A case study is presented on the analysis of thin films on metallic surfaces, at ambient and at elevated temperatures.

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49

You, Yalei, Veljko Petkovic, Jackson Tan, Rachael Kroodsma, Wesley Berg, Chris Kidd, and Christa Peters-Lidard. "Evaluation of V05 Precipitation Estimates from GPM Constellation Radiometers Using KuPR as the Reference." Journal of Hydrometeorology 21, no. 4 (April 2020): 705–28. http://dx.doi.org/10.1175/jhm-d-19-0144.1.

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AbstractThis study assesses the level-2 precipitation estimates from 10 radiometers relative to Global Precipitation Measurement (GPM) Ku-band precipitation radar (KuPR) in two parts. First, nine sensors—four imagers [Advanced Microwave Scanning Radiometer 2 (AMSR2) and three Special Sensor Microwave Imager/Sounders (SSMISs)] and five sounders [Advanced Technology Microwave Sounder (ATMS) and four Microwave Humidity Sounders (MHSs)]—are evaluated over the 65°S–65°N region. Over ocean, imagers outperform sounders, primarily due to the usage of low-frequency channels. Furthermore, AMSR2 is clearly superior to SSMISs, likely due to the finer footprint size. Over land all sensors perform similarly except the noticeably worse performance from ATMS and SSMIS-F17. Second, we include the Sondeur Atmospherique du Profil d’Humidite Intertropicale par Radiometrie (SAPHIR) into the evaluation process, contrasting it against other sensors in the SAPHIR latitudes (30°S–30°N). SAPHIR has a slightly worse detection capability than other sounders over ocean but comparable detection performance to MHSs over land. The intensity estimates from SAPHIR show a larger normalized root-mean-square-error over both land and ocean, likely because only 183.3-GHz channels are available. Currently, imagers are preferred to sounders when level-2 estimates are incorporated into level-3 products. Our results suggest a sensor-specific priority order. Over ocean, this study indicates a priority order of AMSR2, SSMISs, MHSs and ATMS, and SAPHIR. Over land, SSMIS-F17, ATMS and SAPHIR should be given a lower priority than the other sensors.

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50

Jende, P., M. Peter, M. Gerke, and G. Vosselman. "ADVANCED TIE FEATURE MATCHING FOR THE REGISTRATION OF MOBILE MAPPING IMAGING DATA AND AERIAL IMAGERY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (June 3, 2016): 617–23. http://dx.doi.org/10.5194/isprsarchives-xli-b1-617-2016.

Full text

Abstract:

Mobile Mapping’s ability to acquire high-resolution ground data is opposing unreliable localisation capabilities of satellite-based positioning systems in urban areas. Buildings shape canyons impeding a direct line-of-sight to navigation satellites resulting in a deficiency to accurately estimate the mobile platform’s position. Consequently, acquired data products’ positioning quality is considerably diminished. This issue has been widely addressed in the literature and research projects. However, a consistent compliance of sub-decimetre accuracy as well as a correction of errors in height remain unsolved. We propose a novel approach to enhance Mobile Mapping (MM) image orientation based on the utilisation of highly accurate orientation parameters derived from aerial imagery. In addition to that, the diminished exterior orientation parameters of the MM platform will be utilised as they enable the application of accurate matching techniques needed to derive reliable tie information. This tie information will then be used within an adjustment solution to correct affected MM data. This paper presents an advanced feature matching procedure as a prerequisite to the aforementioned orientation update. MM data is ortho-projected to gain a higher resemblance to aerial nadir data simplifying the images’ geometry for matching. By utilising MM exterior orientation parameters, search windows may be used in conjunction with a selective keypoint detection and template matching. Originating from different sensor systems, however, difficulties arise with respect to changes in illumination, radiometry and a different original perspective. To respond to these challenges for feature detection, the procedure relies on detecting keypoints in only one image. Initial tests indicate a considerable improvement in comparison to classic detector/descriptor approaches in this particular matching scenario. This method leads to a significant reduction of outliers due to the limited availability of putative matches and the utilisation of templates instead of feature descriptors. In our experiments discussed in this paper, typical urban scenes have been used for evaluating the proposed method. Even though no additional outlier removal techniques have been used, our method yields almost 90% of correct correspondences. However, repetitive image patterns may still induce ambiguities which cannot be fully averted by this technique. Hence and besides, possible advancements will be briefly presented.

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Journal articles on the topic 'Detector radiometry'

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