Pub Date : 1992-05-26DOI: 10.1109/IGARSS.1992.578378
K. Sarabandi, Y. Oh, F. Ulaby
The recent interest in radar polarimetry has led to the development of several calibration techniques to retrieve the Mueller matrix of a distributed target from the multi-polarization backscatter measurements recorded by the radar system. Existing calibration methods rely on two major assumptions. The first is that the illuminated area of the distributed target is regarded as a single equivalent point target located along the antenna’s boresight direction, and that the statistics of the scattering from all of the measured equivalent point targets are indeed the same as the actual scattering statistics of the distributed target. The second assumption pertains to the process involving the measurement of the radar response of a known point calibration target, located along the boresight direction of the antenna, and then modifying the measured response by a constant, known as the illumination integral, when observing the distributed target. The illumination integral accounts for only magnitude variations of the illuminating fields. Thus, possible phase variations or antenna crosstalk variations across the beam are totally ignored. In this paper a new technique is proposed with which the radar polarization distortion matrix is characterized completely by measuring the polarimetric response of a sphere over the entire main lobe of the antenna. Additionally, the concept of a “differential Mueller matrix” is introduced.
{"title":"Scatterometer Measurement of Differential Mueller Matrix of Distributed Targets","authors":"K. Sarabandi, Y. Oh, F. Ulaby","doi":"10.1109/IGARSS.1992.578378","DOIUrl":"https://doi.org/10.1109/IGARSS.1992.578378","url":null,"abstract":"The recent interest in radar polarimetry has led to the development of several calibration techniques to retrieve the Mueller matrix of a distributed target from the multi-polarization backscatter measurements recorded by the radar system. Existing calibration methods rely on two major assumptions. The first is that the illuminated area of the distributed target is regarded as a single equivalent point target located along the antenna’s boresight direction, and that the statistics of the scattering from all of the measured equivalent point targets are indeed the same as the actual scattering statistics of the distributed target. The second assumption pertains to the process involving the measurement of the radar response of a known point calibration target, located along the boresight direction of the antenna, and then modifying the measured response by a constant, known as the illumination integral, when observing the distributed target. The illumination integral accounts for only magnitude variations of the illuminating fields. Thus, possible phase variations or antenna crosstalk variations across the beam are totally ignored. In this paper a new technique is proposed with which the radar polarization distortion matrix is characterized completely by measuring the polarimetric response of a sphere over the entire main lobe of the antenna. Additionally, the concept of a “differential Mueller matrix” is introduced.","PeriodicalId":441591,"journal":{"name":"[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122375704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-05-26DOI: 10.1109/IGARSS.1992.578455
S. McLaughlin, F. Eaton
Most boundary layer studies of refmtive index fluctuations have centered on the use of tall tower or balloon-borne systems. Often there has beena lack of temporal/spatial resolution and continuity. The U.S. Army Atmospheric Sciences Laboratory (ASL) at White Sands Missile Range is now operating a new Frequency ModulatedContinuous Wave (FM-CW) radar for Boundary Layer (BL) studies. This radar can uniquely obtain continuous ultra-high resolution (1-2m) measurements of radar power return by sensing clear-air turbulent backscattered power from Bragg scattered 5cm turbulent cells from 5Om to 22OOm AGL. Using one antenna to transmit and one to receive, the radar uses an empirical calibration for the first 100 meters above the ante-, and a 1st principles calibration from there up to approximately 2 kilometers to obtain real-time C,2 values. When observing hydrometeor type backscatter, hardware gains can be adjusted to also obtain similar resolution of power return from Rayleigh scattered precipitation. FM-CW measurements can be applied to boundary layer dynamic theory, radio wave propagation, and studies of imaging and laser propagation. A system description describing various salient features, samples of episodal events, and comparison data with a tethered balloon system is shown. BACKGROUND AND INTRODUCTION The first high resolution meteorological FM-CW radar was operated in San Diego in 1969 (Richter, 1969). Originally designed to perform electromagnetic propagation studies for the Navy, the radar proved indispensable in "seeing" air mass layers such as marineldry air boundaries, KelvinHelmholtz (K-H) induced wave structures, and the (at that time) infamous dot angels. The resolution showed such a high level of spactial and temporal detail that often layers were: found to be only a few meters thick, rather than tens of meters (allured to in the Wallops Island multiwavelength radar experiments; Hardy, 1966, and Richter, 1974). Insects could be seen individually with their speed calculated as they were caught up in atmospheric wave motions (Atlas, 19709, and K-H instabilities producing "cat's eyes" were seen in incredible detail (Gossard, 1971). The NOAA Wave Propagation Laboratory, in Boulder, built the second FM-CW radar, adding Doppler winds capability (Chadwick, 19:76), and also calibrated the radar for Gz measurements. The third FMCW radar used for BL studies was delivered to ASL late last year, and incorporates most if not all features of the previous HM-CW radars, and also takes advantage of newer technologies. Following is a system description and discussion of sample data.
{"title":"A New High Resolution Turbulence Profiling Fm-Cw Radar","authors":"S. McLaughlin, F. Eaton","doi":"10.1109/IGARSS.1992.578455","DOIUrl":"https://doi.org/10.1109/IGARSS.1992.578455","url":null,"abstract":"Most boundary layer studies of refmtive index fluctuations have centered on the use of tall tower or balloon-borne systems. Often there has beena lack of temporal/spatial resolution and continuity. The U.S. Army Atmospheric Sciences Laboratory (ASL) at White Sands Missile Range is now operating a new Frequency ModulatedContinuous Wave (FM-CW) radar for Boundary Layer (BL) studies. This radar can uniquely obtain continuous ultra-high resolution (1-2m) measurements of radar power return by sensing clear-air turbulent backscattered power from Bragg scattered 5cm turbulent cells from 5Om to 22OOm AGL. Using one antenna to transmit and one to receive, the radar uses an empirical calibration for the first 100 meters above the ante-, and a 1st principles calibration from there up to approximately 2 kilometers to obtain real-time C,2 values. When observing hydrometeor type backscatter, hardware gains can be adjusted to also obtain similar resolution of power return from Rayleigh scattered precipitation. FM-CW measurements can be applied to boundary layer dynamic theory, radio wave propagation, and studies of imaging and laser propagation. A system description describing various salient features, samples of episodal events, and comparison data with a tethered balloon system is shown. BACKGROUND AND INTRODUCTION The first high resolution meteorological FM-CW radar was operated in San Diego in 1969 (Richter, 1969). Originally designed to perform electromagnetic propagation studies for the Navy, the radar proved indispensable in \"seeing\" air mass layers such as marineldry air boundaries, KelvinHelmholtz (K-H) induced wave structures, and the (at that time) infamous dot angels. The resolution showed such a high level of spactial and temporal detail that often layers were: found to be only a few meters thick, rather than tens of meters (allured to in the Wallops Island multiwavelength radar experiments; Hardy, 1966, and Richter, 1974). Insects could be seen individually with their speed calculated as they were caught up in atmospheric wave motions (Atlas, 19709, and K-H instabilities producing \"cat's eyes\" were seen in incredible detail (Gossard, 1971). The NOAA Wave Propagation Laboratory, in Boulder, built the second FM-CW radar, adding Doppler winds capability (Chadwick, 19:76), and also calibrated the radar for Gz measurements. The third FMCW radar used for BL studies was delivered to ASL late last year, and incorporates most if not all features of the previous HM-CW radars, and also takes advantage of newer technologies. Following is a system description and discussion of sample data.","PeriodicalId":441591,"journal":{"name":"[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123715759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-05-26DOI: 10.1109/IGARSS.1992.576664
R.M. Cmnablitt, M. Bell
The distribution of elemental scatterers on a surface imaged by a synthetic aperture radar (SAR) s y s tem, is modelled as a parametric point process. By describing the surface structure on very small scales, the proposed surface regularity model can account for the effects of sub-resolution structure on the observed signals. The effects are most noticeable in the frequency domain, suggesting that frequency diverse measurements may provide a usefui methdd for estimating the model parameters. Simulation results are presented to illustrate these effects, and directions for further research are suggested.
{"title":"Surface Regularity Modeling And Measurement Using Frequency Diverse Radar Measurements","authors":"R.M. Cmnablitt, M. Bell","doi":"10.1109/IGARSS.1992.576664","DOIUrl":"https://doi.org/10.1109/IGARSS.1992.576664","url":null,"abstract":"The distribution of elemental scatterers on a surface imaged by a synthetic aperture radar (SAR) s y s tem, is modelled as a parametric point process. By describing the surface structure on very small scales, the proposed surface regularity model can account for the effects of sub-resolution structure on the observed signals. The effects are most noticeable in the frequency domain, suggesting that frequency diverse measurements may provide a usefui methdd for estimating the model parameters. Simulation results are presented to illustrate these effects, and directions for further research are suggested.","PeriodicalId":441591,"journal":{"name":"[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123718891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-05-26DOI: 10.1109/IGARSS.1992.576827
D.S. Kirnes, P. Harrison
An extraction technique for inferring physical and biological surface properties of vegetation using nadir and/or directional reflectance data as input has been developed. A knowledge-based system (VEG) accepts spectral data of an unknown target as input, determines the best strategy for inferring the desired vegetation characteristic, applies the strategy to the target data, and provides a rigorous estimate of the accuracy of the inference. Progress in developing the system is presented. VEG combines methods from remote sensing and artificial intelligence, and integrates input spectral measurements with diverse knowledge bases. VEG has been developed to (1) infer spectral hemispherical reflectance from any combination of nadir and/or off-nadir view angles; (2) test and develop new extraction techniques on an internal spectral database; (3) browse, plot, or analyze directional reflectance data in the system's spectral database; (4) discriminate between user-defined vegetation classes using spectral and directional reflectance relationships; and (5) infer unknown view angles from known view angles (known as view angle extension).
{"title":"New Developments Of A Knowledge Based System (veg) For Inferring Vegetation Characteristics","authors":"D.S. Kirnes, P. Harrison","doi":"10.1109/IGARSS.1992.576827","DOIUrl":"https://doi.org/10.1109/IGARSS.1992.576827","url":null,"abstract":"An extraction technique for inferring physical and biological surface properties of vegetation using nadir and/or directional reflectance data as input has been developed. A knowledge-based system (VEG) accepts spectral data of an unknown target as input, determines the best strategy for inferring the desired vegetation characteristic, applies the strategy to the target data, and provides a rigorous estimate of the accuracy of the inference. Progress in developing the system is presented. VEG combines methods from remote sensing and artificial intelligence, and integrates input spectral measurements with diverse knowledge bases. VEG has been developed to (1) infer spectral hemispherical reflectance from any combination of nadir and/or off-nadir view angles; (2) test and develop new extraction techniques on an internal spectral database; (3) browse, plot, or analyze directional reflectance data in the system's spectral database; (4) discriminate between user-defined vegetation classes using spectral and directional reflectance relationships; and (5) infer unknown view angles from known view angles (known as view angle extension).","PeriodicalId":441591,"journal":{"name":"[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126928638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-05-26DOI: 10.1109/IGARSS.1992.576693
M. Migliaccio
A SAR raw signal simulator can be very useful in post processing techniques. In the following paper we deal with a first application of SARAS (Synthetic Aperture Radar Advanced Simulator) in edge-detection procedures. In particular, SARAS adpropriately simulates the raw signal received on board of the sensor, then we process it in order to produce the relative image. Henceforth post-processing techniques can be applied to the simulated image. Experiments are here shown: visual and quantitative inspections are in very good agreement with results obtained on real SAR images. Such outcomes encourages future work on such field. I
{"title":"Use Of SARAS In Post-processing Techniques","authors":"M. Migliaccio","doi":"10.1109/IGARSS.1992.576693","DOIUrl":"https://doi.org/10.1109/IGARSS.1992.576693","url":null,"abstract":"A SAR raw signal simulator can be very useful in post processing techniques. In the following paper we deal with a first application of SARAS (Synthetic Aperture Radar Advanced Simulator) in edge-detection procedures. In particular, SARAS adpropriately simulates the raw signal received on board of the sensor, then we process it in order to produce the relative image. Henceforth post-processing techniques can be applied to the simulated image. Experiments are here shown: visual and quantitative inspections are in very good agreement with results obtained on real SAR images. Such outcomes encourages future work on such field. I","PeriodicalId":441591,"journal":{"name":"[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130626698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-05-26DOI: 10.1109/IGARSS.1992.578630
C. Evans, M. Helfert, D. Helms
Earth photography from the Space Shuttle is used to examine the ice cover on Lake Baikal and correlate the patterns of weakened and melting ice with known hydrothermal areas in the Siberian lake. Particular zones of melted and broken ice may be surface expressions of elevated heat flow in Lake Baikal. The possibility is explored that hydrothermal vents can introduce local convective upwelling and disrupt a stable water column to the extent that the melt zones which are observed in the lake's ice cover are produced. A heat flow map and photographs of the lake are overlaid to compare specific areas of thinned or broken ice with the hot spots. The regions of known hydrothermal activity and high heat flow correlate extremely well with circular regions of thinned ice, and zones of broken and recrystallized ice. Local and regional climate data and other sources of warm water, such as river inlets, are considered.
{"title":"Ice Patterns and Hydrothermal Plumes, Lake Baikal, Russia: Insights from Space Shuttle Hand-Held Photography","authors":"C. Evans, M. Helfert, D. Helms","doi":"10.1109/IGARSS.1992.578630","DOIUrl":"https://doi.org/10.1109/IGARSS.1992.578630","url":null,"abstract":"Earth photography from the Space Shuttle is used to examine the ice cover on Lake Baikal and correlate the patterns of weakened and melting ice with known hydrothermal areas in the Siberian lake. Particular zones of melted and broken ice may be surface expressions of elevated heat flow in Lake Baikal. The possibility is explored that hydrothermal vents can introduce local convective upwelling and disrupt a stable water column to the extent that the melt zones which are observed in the lake's ice cover are produced. A heat flow map and photographs of the lake are overlaid to compare specific areas of thinned or broken ice with the hot spots. The regions of known hydrothermal activity and high heat flow correlate extremely well with circular regions of thinned ice, and zones of broken and recrystallized ice. Local and regional climate data and other sources of warm water, such as river inlets, are considered.","PeriodicalId":441591,"journal":{"name":"[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130928070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-05-26DOI: 10.1109/IGARSS.1992.578323
R.K. Moore, M. Stuart, W. Xin, T. Propp
Modeling global atmospheric circulations and forecasting the weather would improve if worldwide information on winds aloft were available. Accurate prediction of weather is important to agriculture, shipping, air traffic, and many other fields. Global system models of climate are of great importance. Current global atmospheric models use pressure measurements and thermodynamic properties to calculate the effects of wind for use in Numerical Weather Prediction (NWP) models. Inputs to the NWP models are temperature, pressure and wind velocities at different heights. Clearly direct wind measurements could significantly improve the NWP model performance. The RAdar Wind Sounder (RAWS) program at the University of Kansas is a study of the feasibility and the trade-offs in the design of a space-based radar system to measure wind vectors. This can be done by measuring the Doppler shift of cloud and rain returns from three or more points and calculating the components of the wind vector. The RAWS study to date uses the candidate system selected after preliminary study of frequencies and sensitivities. Two frequencies chosen, 10 and 35 GHz, allow higher sensitivity for clouds and more penetration for rain. The past year was devoted to modeling the signal-to-noise ratio (SNR) achievable for the two frequencies. The determination of SNR versus cloud penetration depth used a cloud backscattering and attenuation model in the appropriate radar equation. Calculations assumed reasonable losses in reception and transmission, in addition to the atmospheric attenuation. We discovered that ice clouds provide a higher SNR than previously calculated, but some water clouds give lower SNRs than we calculated before. One of the primary issues in the SNR calculation was the choice of the drop size distribution. Although Xin used several distributions (e.g., log normal, Khrigian and Mazin), this year we used the Deirmendjian cloud model. SNR versus cloud penetration plots were generated to validate the candidate system. Rain, which appears in the cloud models at the lower altitudes, provides ample SNR, as do the higher clouds composed of ice particles. However, in some cloud situations we found the sensitivity for the clouds was marginal or inadequate. At 35 GHz, two of the cloud models characterized by 1 to 2 g/cu m of water content at altitudes extending from 150 to 1500 meters, produced a sufficient SNR. Other models, however, with water contents ranging from 0.5 to 4 g/cu m and altitudes up to 4000 meters, exhibit SNR of -3 to -23 dB, largely because of attenuation in the upper cloud layers. These results coupled with the lower SNR at 10 GHz, led to an investigation of alternate frequencies. The rain present beneath these clouds provides adequate SNR at 10 GHz, and in most cases, at GHz.
{"title":"A Satellite-Borne Radar Wind Sensor (raws)","authors":"R.K. Moore, M. Stuart, W. Xin, T. Propp","doi":"10.1109/IGARSS.1992.578323","DOIUrl":"https://doi.org/10.1109/IGARSS.1992.578323","url":null,"abstract":"Modeling global atmospheric circulations and forecasting the weather would improve if worldwide information on winds aloft were available. Accurate prediction of weather is important to agriculture, shipping, air traffic, and many other fields. Global system models of climate are of great importance. Current global atmospheric models use pressure measurements and thermodynamic properties to calculate the effects of wind for use in Numerical Weather Prediction (NWP) models. Inputs to the NWP models are temperature, pressure and wind velocities at different heights. Clearly direct wind measurements could significantly improve the NWP model performance. The RAdar Wind Sounder (RAWS) program at the University of Kansas is a study of the feasibility and the trade-offs in the design of a space-based radar system to measure wind vectors. This can be done by measuring the Doppler shift of cloud and rain returns from three or more points and calculating the components of the wind vector. The RAWS study to date uses the candidate system selected after preliminary study of frequencies and sensitivities. Two frequencies chosen, 10 and 35 GHz, allow higher sensitivity for clouds and more penetration for rain. The past year was devoted to modeling the signal-to-noise ratio (SNR) achievable for the two frequencies. The determination of SNR versus cloud penetration depth used a cloud backscattering and attenuation model in the appropriate radar equation. Calculations assumed reasonable losses in reception and transmission, in addition to the atmospheric attenuation. We discovered that ice clouds provide a higher SNR than previously calculated, but some water clouds give lower SNRs than we calculated before. One of the primary issues in the SNR calculation was the choice of the drop size distribution. Although Xin used several distributions (e.g., log normal, Khrigian and Mazin), this year we used the Deirmendjian cloud model. SNR versus cloud penetration plots were generated to validate the candidate system. Rain, which appears in the cloud models at the lower altitudes, provides ample SNR, as do the higher clouds composed of ice particles. However, in some cloud situations we found the sensitivity for the clouds was marginal or inadequate. At 35 GHz, two of the cloud models characterized by 1 to 2 g/cu m of water content at altitudes extending from 150 to 1500 meters, produced a sufficient SNR. Other models, however, with water contents ranging from 0.5 to 4 g/cu m and altitudes up to 4000 meters, exhibit SNR of -3 to -23 dB, largely because of attenuation in the upper cloud layers. These results coupled with the lower SNR at 10 GHz, led to an investigation of alternate frequencies. The rain present beneath these clouds provides adequate SNR at 10 GHz, and in most cases, at GHz.","PeriodicalId":441591,"journal":{"name":"[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128800165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-05-26DOI: 10.1109/IGARSS.1992.578439
W. Boerner, M. Walther, A. Segal
Speckle reduction has long been recognized as the main problem of coherent imaging and many processing techniques have been advanced to overcome it. The vast majority of these techniques, however, are of a scalar nature simply because vector/matrix imaging data are so sparse and have become available only very recently. We do have such data, which was taken with the NASA/JPL cir-990 dual-polarization L-band (1.225 GHZ) SAR (Synthetic Aperture Radar) system, have been made available to us. we investigate the potential of an exclusively polarimetric image filtering approach, which takes f u l l advantage of the matrix data provided on a pixel-by-pixel basis, and complements the existing scalar contrast optimization and speckle reduction techniques. We wish to stress from the outset that our goal is contrast optimization without the help of incoherent averaging over pixels/look, because of the corresponding loss of spatial or temporal resolution.
{"title":"An Analysis of the Polarimetric Matched Signal and Image Filter: Application to Radar Target Versus Clutter Optimal Discrimination in Pol-Sar Image","authors":"W. Boerner, M. Walther, A. Segal","doi":"10.1109/IGARSS.1992.578439","DOIUrl":"https://doi.org/10.1109/IGARSS.1992.578439","url":null,"abstract":"Speckle reduction has long been recognized as the main problem of coherent imaging and many processing techniques have been advanced to overcome it. The vast majority of these techniques, however, are of a scalar nature simply because vector/matrix imaging data are so sparse and have become available only very recently. We do have such data, which was taken with the NASA/JPL cir-990 dual-polarization L-band (1.225 GHZ) SAR (Synthetic Aperture Radar) system, have been made available to us. we investigate the potential of an exclusively polarimetric image filtering approach, which takes f u l l advantage of the matrix data provided on a pixel-by-pixel basis, and complements the existing scalar contrast optimization and speckle reduction techniques. We wish to stress from the outset that our goal is contrast optimization without the help of incoherent averaging over pixels/look, because of the corresponding loss of spatial or temporal resolution.","PeriodicalId":441591,"journal":{"name":"[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126206565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-05-26DOI: 10.1109/IGARSS.1992.578835
A. Ehsani, J. Reagan
paper describes the design and fabricm'on of a microprocessor controlled auto sun-tracking lkhannel solar radiometer system which is used in measuring the solar spectral irradiance received at the Earth's suface. The instrument measurements are employed in determining the atmospheric optical depths at 10 discrete wavelengths through visible and near IR regions. me automated solar radiometer is capable of tracking the sun, and measuring and recording the output of 10 channels through the course of a day. Some pe formance and experimental results of the instrument are also presented in this paper.
{"title":"A Microprocessor Based Auto Sun-Tracking Multi-Channel Solar Radiometer System","authors":"A. Ehsani, J. Reagan","doi":"10.1109/IGARSS.1992.578835","DOIUrl":"https://doi.org/10.1109/IGARSS.1992.578835","url":null,"abstract":"paper describes the design and fabricm'on of a microprocessor controlled auto sun-tracking lkhannel solar radiometer system which is used in measuring the solar spectral irradiance received at the Earth's suface. The instrument measurements are employed in determining the atmospheric optical depths at 10 discrete wavelengths through visible and near IR regions. me automated solar radiometer is capable of tracking the sun, and measuring and recording the output of 10 channels through the course of a day. Some pe formance and experimental results of the instrument are also presented in this paper.","PeriodicalId":441591,"journal":{"name":"[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121629360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-05-26DOI: 10.1109/IGARSS.1992.578277
Shih Tang, Jin Wu
As a part of the Synthetic Aperture Radar XBand Ocean Nonlinearlity - Forschungs Platform NORDSEE (SAXON-FPN) Experiment, measurements of ocean-ripple curvatures were performed with an optical sensing system supported at 30 m above the mean sea surface. At nadir, radii of curvature between 2 and 8 mm were obtained under wind speeds ranging from 2.7 to 21 m/s and generally unstable atmospheric stability conditions. The mean radii of curvature reveal a weak dependence on the wind velocity. Mean radii of curvature over clean and slick surfaces were also observed.
{"title":"Measurements of Ocean-Ripple Curvatures","authors":"Shih Tang, Jin Wu","doi":"10.1109/IGARSS.1992.578277","DOIUrl":"https://doi.org/10.1109/IGARSS.1992.578277","url":null,"abstract":"As a part of the Synthetic Aperture Radar XBand Ocean Nonlinearlity - Forschungs Platform NORDSEE (SAXON-FPN) Experiment, measurements of ocean-ripple curvatures were performed with an optical sensing system supported at 30 m above the mean sea surface. At nadir, radii of curvature between 2 and 8 mm were obtained under wind speeds ranging from 2.7 to 21 m/s and generally unstable atmospheric stability conditions. The mean radii of curvature reveal a weak dependence on the wind velocity. Mean radii of curvature over clean and slick surfaces were also observed.","PeriodicalId":441591,"journal":{"name":"[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium","volume":"282 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116079666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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