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- 2015
- Calibration process of OSL detectors
- Iodine-131
- OSL-BeO
- Dosimetry of staff and patients
- Optically Stimulated Luminescence (OSL)
- Akdeniz University
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[IEEE 2018 10th International Conference on Communication Software and Networks (ICCSN) - Chengdu (2018.7.6-2018.7.9)] 2018 10th International Conference on Communication Software and Networks (ICCSN) - An Amplitude-phase Measurement Method of Phased Array Antenna Based on Self-Calibration RF Channel
摘要： Caused by the amplitude-phase error of phased array antenna, the pattern performance unable to meet the optimum design results. Thus, the phase and amplitude of phased array antenna should be measured and calibrated. An measurement method of phased array antenna based on self-calibration RF channel is presented in this paper. First of all, the initial amplitude-phase is measured by self-calibration RF channel. Secondly, the modified value related to self-calibration RF channel is achieved by use of Mid-field receiving power calculation method. Finally, the actual amplitude and phase weighting factor of phased array antenna is obtained, based on calibration of the initial amplitude-phase with the modified value. The comparison of planar near-field measured results show that the proposed method is feasible and efficient.
关键词： amplitude-phase measurement method,self-calibration,phased array antenna
更新于2025-09-10 09:29:36
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Reflectance-Based Imaging Spectrometer Error Budget Field Practicum at the Railroad Valley Test Site, Nevada [Technical Committees]
摘要： Calibration and validation determine the quality and integrity of the data provided by sensors and have enormous downstream impacts on the accuracy and reliability of the products generated by these sensors. With the imminent launch of the next generation of spaceborne imaging spectroscopy sensors, the IEEE Geoscience and Remote Sensing Society’s (GRSS’s) Geoscience Spaceborne Imaging Spectroscopy Technical Committee (GSIS TC) initiated a calibration and validation initiative. This article reports on a recent reflectance-based imaging spectrometer error budget field practicum focused on radiometric calibration of spaceborne imaging spectroscopy sensors. The field exercise, conducted at Railroad Valley in Nevada, provided valuable training for personnel in a variety of Earth observation (EO) areas, from engineers developing future sensors to calibration scientists actively working in the field.
关键词： validation,radiometric calibration,imaging spectroscopy,calibration,vicarious calibration
更新于2025-09-09 09:28:46
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The Polarimetric L-Band Imaging Synthetic Aperture Radar (PLIS): Description, Calibration, and Cross-Validation
摘要： The polarimetric L-band imaging synthetic aperture radar (PLIS) is a high spatial resolution (better than 6 m) airborne synthetic aperture radar system that has been dedicated to scientific research into civilian applications since 2010. The weight of PLIS is ～38 kg, allowing it to be installed aboard small low-cost aircraft, with two antennas used to measure the full backscatter matrix for a swath between 15° and 50° on each side of the flight direction. Calibration based on a total of 96 calibration points and a homogeneous forest during the two recent soil moisture active passive experiments (SMAPEx-4 and 5) showed an overall radiometric accuracy of 0.58 dB (root-mean-square error) over trihedral passive radar calibrators. Independent evaluation based on polarimetric active radar calibrators showed an amplitude imbalance of 0.17 dB with a standard deviation of 0.15 dB and a phase imbalance of 3.87° with a standard deviation of 2.86°. Two calibrated phased-array L-Band synthetic aperture radar-2 (PALSAR-2) images with different observation modes (ScanSAR and Stripmap) were compared with the calibrated PLIS images. The agreement between PALSAR-2 Stripmap and PLIS had a root mean square difference of 1.27 dB and a correlation coefficient of 0.87. Further comparisons over different landcover types confirmed that homogeneous forest and grassland areas constitute optimal targets for cross-validation and/or calibration.
关键词： Calibration and validation,phased-array L-Band synthetic aperture radar-2 (PALSAR-2),cross-calibration,synthetic aperture radar (SAR),polarimetric L-band imaging SAR (PLIS)
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Phase Error Compensation in Multi-Baseline SAR Tomography
摘要： This paper explores the main issue surrounding the multi-dimensional synthetic aperture radar (SAR) image focusing techniques, suchlike those caused by the atmosphere propagation delays or by residual platform motion. The problem brings unknown contributions to the phases of complex received signal that it is generally independent of acquisitions track to track and leads spreading and defocusing in multi-dimensional space. To deal with these issues, in this paper an auto-focusing procedure based on sharpness optimization of the reconstructed signal has been employed. The main concern about this technique is that sharpness optimization by itself however can introduce unwanted and uncontrollable vertical shifts in the focused image. To tackle this issue, the phase error is estimated by multiple integration of second derivative of the phase with respect to baseline. The estimation of the calibration phase is performed by optimizing contrast or entropy of the vertical profile with the constraint of a zero phase derivative. In this way, unwanted vertical shifts are avoided and the correct height reference is preserved. Experimental results from the proposed method are evaluated by vertical profile reconstruction performance in the controlled conditions by simulated dataset over the forested area and multi-baseline data acquired by ONERA in Guyana in the frame of European space agency’s campaign TROPISAR.
关键词： synthetic aperture radar (SAR),tomography,Phase calibration,volumetric media
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Calibration Challenges for the Biomass P-Band SAR Instrument
摘要： The BIOMASS mission gives completely new challenges in external calibration arising from the orbital pattern needed for the tomographic and Pol-InSAR phases of the mission, the strong effects of the ionosphere at P-band, and the lack of pre-existing P-band data except over very limited parts of the globe. Together these create problems that can only be solved by combining infrequent visits to instrumented calibration sites with systematic exploitation of the properties of distributed targets and targets of opportunity. Proposed approaches to performing radiometric and polarimetric calibration are described, together with meeting geolocation accuracy requirements.
关键词： calibration,Radiometry,ionospheric correction,geolocation,polarimetry
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Radiometric Performance of Multispectral Camera Applied to Operational Precision Agriculture
摘要： The use of multispectral sensors onboard of unmanned vehicles is nowadays a common practice in precision agriculture. Their radiometric behavior is an important issue to ensure comparable information along space and time. A calibration of a Sequoia? camera is conducted in terms of reflectance and NDVI, taking benefit from a wheat cover field work. The output reflectance values in the green and red channel show linear behavior in the range of 0.00 to 0.45, with a saturation over this value. The red edge and NIR channels show linear behavior in the whole reflectance range, with better performance in the NIR than in the red-edge channel. The NDVI has a good agreement with field measurements, near the 1:1 line, showing the highest variability for the lower values due to heterogeneity of soil brightness linked to variations in soil moisture.
关键词： NDVI,Reflectance,Multispectral Camera,Radiometric Calibration
更新于2025-09-09 09:28:46
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Soumi NPP VIIRS Day/Night Band Stray Light Characterization and Correction Using Calibration View Data
摘要： The Soumi NPP VIIRS Day/Night Band (DNB) nighttime imagery quality is affected by stray light contamination. In this study, we examined the relationship between the Earth scene stray light and the signals in VIIRS’s calibrators to better understand stray light characteristics and to improve upon the current correction method. Our analyses showed the calibrator signal to be highly predictive of Earth scene stray light and can provide additional stray light characteristics that are dif?cult to obtain from Earth scene data alone. In the current stray light correction regions (mid-to-high latitude), the stray light onset angles can be tracked by calibration view data to reduce correction biases. In the southern hemisphere, it is possible to identify the angular extent of the additional stray light feature in the calibration view data and develop a revised correction method to remove the additional stray light occurring during the southern hemisphere springtime. Outside of current stray light correction region, the analysis of calibration view data indicated occasional stray light contamination at low latitude and possible background biases caused by Moon illumination. As stray light affects a signi?cant portion of nighttime scenes, further re?nement in characterization and correction is important to ensure VIIRS DNB imagery quality for Soumi NPP and future missions.
关键词： remote sensing,on-orbit calibration,moon,nighttime lights,stray light,VIIRS,VIS/NIR,Day/Night Band
更新于2025-09-09 09:28:46
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Radiometric Cross-Calibration of GF-4 PMS Sensor Based on Assimilation of Landsat-8 OLI Images
摘要： Earth observation data obtained from remote sensors must undergo radiometric calibration before use in quantitative applications. However, the large view angles of the panchromatic multispectral sensor (PMS) aboard the GF-4 satellite pose challenges for cross-calibration due to the effects of atmospheric radiation transfer and the bidirectional reflectance distribution function (BRDF). To address this problem, this paper introduces a novel cross-calibration method based on data assimilation considering cross-calibration as an optimal approximation problem. The GF-4 PMS was cross-calibrated with the well-calibrated Landsat-8 Operational Land Imager (OLI) as the reference sensor. In order to correct unequal bidirectional reflection effects, an adjustment factor for the BRDF was established, making complex models unnecessary. The proposed method employed the Shuffled Complex Evolution-University of Arizona (SCE-UA) algorithm to find the optimal calibration coefficients and BRDF adjustment factor through an iterative process. The validation results revealed a surface reflectance error of <5% for the new cross-calibration coefficients. The accuracy of calibration coefficients were significantly improved when compared to the officially published coefficients as well as those derived using conventional methods. The uncertainty produced by the proposed method was less than 7%, meeting the demands for future quantitative applications and research. This method is also applicable to other sensors with large view angles.
关键词： GF-4 PMS,cross-calibration,SCE-UA,data assimilation,Landsat-8 OLI,BRDF
更新于2025-09-09 09:28:46
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Polarimetric Calibration of CASMSAR P-Band Data Affected by Terrain Slopes Using a Dual-Band Data Fusion Technique
摘要： For airborne synthetic aperture radar (SAR) polarimetric calibration (PolCAL) based on distributed targets, it is important to ensure the removal of both the polarimetric distortion and terrain slope effect. This paper proposes a new technique for PolCAL in mountainous areas, without the use of corner reflectors (CRs). The technique based on dual-band data fusion consists of two steps. First, the polarization orientation angle shift (POAS), as a priori asymmetry information, is derived from X-band interferometry and applied to P-band fully-polarimetric data. Second, the crosstalk and cross-polarization (cross-pol) channel imbalance are iteratively determined using the POAS after dual-band data fusion. The performance and feasibility of the technique was evaluated by CRs. It was demonstrated that the proposed technique is capable of deriving the distortion parameters and performs better than the methods presented in Quegan and Ainsworth et al. The signal-to-noise ratio (SNR) and pedestal height have been investigated in polarimetric signatures. The proposed technique is useful for PolCAL in mountainous areas and for monitoring systems without CRs in long-term operation.
关键词： SAR,Chinese Academy of Surveying and Mapping Synthetic Aperture Radar (CASMSAR),polarimetric calibration,polarization orientation angle shift,data fusion
更新于2025-09-09 09:28:46
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[ACS Symposium Series] Raman Spectroscopy in the Undergraduate Curriculum Volume 1305 || Exploring the Figures of Merit of Surface-Enhanced Raman Spectroscopy
摘要： This undergraduate laboratory experiment is designed to help students gain a deeper understanding of surface-enhanced Raman spectroscopy (SERS). Students will learn to fabricate nanoparticles, obtain Raman and SERS data, construct calibration curves, and determine the signal-to-noise ratio, limit of detection, and coefficient of variation of alizarin, a dye molecule commonly found in cultural heritage materials. Overall, the laboratory experiment will provide an opportunity for students to develop laboratory skills in nanoscience and spectroscopy and further develop their critical thinking skills.
关键词： SERS,surface-enhanced Raman spectroscopy,limit of detection,calibration curves,alizarin,signal-to-noise ratio,nanoparticles,coefficient of variation
更新于2025-09-09 09:28:46