Analysis and Model of SAR Radiometric Calibration in Near-Space

2013 ◽  
Vol 321-324 ◽  
pp. 842-846
Author(s):  
Song Tian ◽  
Jian She Song ◽  
Tie Jian Yang ◽  
Lian Feng Wang ◽  
Bao Shun Zhou
Keyword(s):  
Experimental Data ◽  
Calibration Method ◽  
Synthetic Aperture ◽  
Calibration Model ◽  
Radiometric Calibration ◽  
Backscattering Coefficient ◽  
Important Work ◽  
Work Related ◽  
Near Space ◽  
The Difference

Radiometric calibration of synthetic aperture radar (SAR) is an important work related to pixel values and the backscattering coefficient of ground targets. With a consideration of the difference between near space and spaceborne, airborne platforms, this paper proposes the radiometric calibration method which is applicable to near space platform. A radiometric calibration model of near space SAR is established, and it is analyzed and validated by experimental data.

scholarly journals On-Orbit Polarization Calibration for Multichannel Polarimetric Camera

2019 ◽  
Vol 9 (7) ◽  
pp. 1424 ◽  
Author(s):  
Mingxin Liu ◽  
Xin Zhang ◽  
Tao Liu ◽  
Guangwei Shi ◽  
Lingjie Wang ◽  
...  
Keyword(s):  
Linear Polarization ◽  
Calibration Method ◽  
Experimental Results ◽  
Calibration Model ◽  
Radiometric Calibration ◽  
Relative Deviation ◽  
Transmission Process ◽  
Radiation Transmission ◽  
Polarimetric Imaging ◽  
Imaging Detection

In this paper, a new on-orbit polarization calibration method for the multichannel polarimetric camera is presented. A polarization calibration model for the polarimetric camera is proposed by taking analysis of the polarization radiation transmission process. In order to get the polarization parameters in the calibration model, an on-orbit measurement scheme is reported, which uses a solar diffuser and a built-in rotatable linear analyzer. The advantages of this scheme are sharing the same calibration assembly with the radiometric calibration and acquiring sufficient polarization accuracy. The influence of the diffuser for the measurement is analyzed. By using a verification experiment, the proposed method can achieve on-orbit polarization calibration. The experimental results show that the relative deviation for the measured degree of linear polarization is 0.8% at 670 nm, which provides a foundation for the accurate application of polarimetric imaging detection.

scholarly journals Polarization Radiometric Calibration in Laboratory for a Channeled Spectropolarimeter

2020 ◽  
Vol 10 (22) ◽  
pp. 8295
Author(s):  
Wenhe Xing ◽  
Xueping Ju ◽  
Jian Bo ◽  
Changxiang Yan ◽  
Bin Yang ◽  
...  
Keyword(s):  
Optical System ◽  
Measurement Accuracy ◽  
Calibration Method ◽  
Stokes Parameters ◽  
Calibration Coefficient ◽  
Calibration Model ◽  
Radiometric Calibration ◽  
Reconstruction Methods ◽  
Proposed Model ◽  
Alignment Errors

The process of radiometric calibration would be coupled with the polarization properties of an optical system for spectropolarimetry, which would have significant influences on reconstructed Stokes parameters. In this paper, we propose a novel polarization radiometric calibration model that decouples the radiometric calibration coefficient and polarization properties of an optical system. The alignment errors of the polarization module and the variation of the retardations at different fields of view are considered and calibrated independently. According to these calibration results, the input Stokes parameters at different fields of view can be reconstructed accurately through the proposed model. Simulations are performed for the presented calibration and reconstruction methods, which indicate that the measurement accuracy of polarization information is improved compared with the traditional undecoupled calibration method.

scholarly journals Validation Metrics for Fixed Effects and Mixed-Effects Calibration

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Nathan W. Porter ◽  
Kathryn A. Maupin ◽  
Laura P. Swiler ◽  
Vincent A. Mousseau
Keyword(s):  
Experimental Data ◽  
Computational Model ◽  
Fixed Effects ◽  
Calibration Method ◽  
Mixed Effects ◽  
Calibration Model ◽  
Fixed Effects Model ◽  
Validation Metrics ◽  
Calibration Methods ◽  
History Of Use

Abstract The modern scientific process often involves the development of a predictive computational model. To improve its accuracy, a computational model can be calibrated to a set of experimental data. A variety of validation metrics can be used to quantify this process. Some of these metrics have direct physical interpretations and a history of use, while others, especially those for probabilistic data, are more difficult to interpret. In this work, a variety of validation metrics are used to quantify the accuracy of different calibration methods. Frequentist and Bayesian perspectives are used with both fixed effects and mixed-effects statistical models. Through a quantitative comparison of the resulting distributions, the most accurate calibration method can be selected. Two examples are included which compare the results of various validation metrics for different calibration methods. It is quantitatively shown that, in the presence of significant laboratory biases, a fixed effects calibration is significantly less accurate than a mixed-effects calibration. This is because the mixed-effects statistical model better characterizes the underlying parameter distributions than the fixed effects model. The results suggest that validation metrics can be used to select the most accurate calibration model for a particular empirical model with corresponding experimental data.

scholarly journals Vicarious Radiometric Calibration of Ocean Color Bands for FY-3D/MERSI-II at Lake Qinghai, China

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 139
Author(s):  
Shengli Chen ◽  
Xiaobing Zheng ◽  
Xin Li ◽  
Wei Wei ◽  
Shenda Du ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Large Deviation ◽  
Ocean Color ◽  
Calibration Method ◽  
Surface Measurement ◽  
Radiometric Calibration ◽  
Lake Qinghai ◽  
Vicarious Calibration ◽  
Calibration Methods ◽  
Spectral Imager

To calibrate the low signal response of the ocean color (OC) bands and test the stability of the Fengyun-3D (FY-3D)/Medium Resolution Spectral Imager II (MERSI-II), an absolute radiometric calibration field test of FY-3D/MERSI-II at the Lake Qinghai Radiometric Calibration Site (RCS) was carried out in August 2018. The lake surface and atmospheric parameters were mainly measured by advanced observation instruments, and the MODerate spectral resolution atmospheric TRANsmittance algorithm and computer model (MODTRAN4.0) was used to simulate the multiple scattering radiance value at the altitude of the sensor. The results showed that the relative deviations between bands 9 and 12 are within 5.0%, while the relative deviations of bands 8, and 13 are 17.1%, and 12.0%, respectively. The precision of the calibration method was verified by calibrating the Aqua/Moderate-resolution Imaging Spectroradiometer (MODIS) and National Polar-orbiting Partnership (NPP)/Visible Infrared Imaging Radiometer (VIIRS), and the deviation of the calibration results was evaluated with the results of the Dunhuang RCS calibration and lunar calibration. The results showed that the relative deviations of NPP/VIIRS were within 7.0%, and the relative deviations of Aqua/MODIS were within 4.1% from 400 nm to 600 nm. The comparisons of three on-orbit calibration methods indicated that band 8 exhibited a large attenuation after launch and the calibration results had good consistency at the other bands except for band 13. The uncertainty value of the whole calibration system was approximately 6.3%, and the uncertainty brought by the field surface measurement reached 5.4%, which might be the main reason for the relatively large deviation of band 13. This study verifies the feasibility of the vicarious calibration method at the Lake Qinghai RCS and provides the basis and reference for the subsequent on-orbit calibration of FY-3D/MERSI-II.

scholarly journals Epistemic values of quantity and variety of evidence in biological mechanism research

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Yin Chung Au
Keyword(s):  
Experimental Data ◽  
Causal Inference ◽  
Case Studies ◽  
Biological Mechanism ◽  
Data Generation ◽  
Extended Version ◽  
Epistemic Values ◽  
Difference Making ◽  
Mechanism Research ◽  
The Difference

AbstractThis paper proposes an extended version of the interventionist account for causal inference in the practical context of biological mechanism research. This paper studies the details of biological mechanism researchers’ practices of assessing the evidential legitimacy of experimental data, arguing why quantity and variety are two important criteria for this assessment. Because of the nature of biological mechanism research, the epistemic values of these two criteria result from the independence both between the causation of data generation and the causation in question and between different interventions, not techniques. The former independence ensures that the interventions in the causation in question are not affected by the causation that is responsible for data generation. The latter independence ensures the reliability of the final mechanisms not only in the empirical but also the formal aspects. This paper first explores how the researchers use quantity to check the effectiveness of interventions, where they at the same time determine the validity of the difference-making revealed by the results of interventions. Then, this paper draws a distinction between experimental interventions and experimental techniques, so that the reliability of mechanisms, as supported by the variety of evidence, can be safely ensured in the probabilistic sense. The latter process is where the researchers establish evidence of the mechanisms connecting the events of interest. By using case studies, this paper proposes to use ‘intervention’ as the fruitful connecting point of literature between evidence and mechanisms.

Dose-window dependence on Si crystal orientation in separation by implanted oxygen substrate formation

2004 ◽  
Vol 19 (12) ◽  
pp. 3607-3613 ◽  
Author(s):  
H. Iikawa ◽  
M. Nakao ◽  
K. Izumi
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Crystal Orientation ◽  
Oxygen Ion ◽  
The Difference ◽  
First Time ◽  
Good Agreement

Separation by implemented oxygen (SIMOX)(111) substrates have been formed by oxygen-ion (16O+) implantation into Si(111), showing that a so-called “dose-window” at 16O+-implantation into Si differs from Si(100) to Si(111). In SIMOX(100), an oxygen dose of 4 × 1017/cm2 into Si(100) is widely recognized as the dose-window when the acceleration energy is 180 keV. For the first time, our work shows that an oxygen dose of 5 × 1017/cm2 into Si(111) is the dose-window for the formation of SIMOX(111) substrates when the acceleration energy is 180 keV. The difference between dose-windows is caused by anisotropy of the crystal orientation during growth of the faceted buried SiO2. We also numerically analyzed the data at different oxidation velocities for each facet of the polyhedral SiO2 islands. Numerical analysis results show good agreement with the experimental data.

The Tensile Property of the SPF/Cotton Blended Yarn

2011 ◽  
Vol 321 ◽  
pp. 192-195
Author(s):  
Qing Bin Yang ◽  
Xiao Yang
Keyword(s):  
Experimental Data ◽  
Simple Model ◽  
Tensile Property ◽  
Cotton Fibers ◽  
Blended Yarn ◽  
The Difference ◽  
The Relationship

In order to analysis the relationship between the strength and elongation and the blended ratio of SPF/Cotton blended yarn, the strength and elongation of SPF /cotton blended yarn with different blended ratio were measured and compared with the simple model. The results indicated that For the SPF/cotton blended yarn, the difference between the experimental data and the model value is remarkable because of the high cohesion of the cotton fibers.

Review Product Distribution Through Different Channels

2021 ◽  
Vol 11 (4) ◽  
pp. 44-47
Author(s):  
Zhaoqiong Qin
Keyword(s):  
Product Distribution ◽  
Future Research ◽  
Direct Channel ◽  
Past Work ◽  
Work Related ◽  
Channel Competition ◽  
Physical Channel ◽  
The Future ◽  
The Difference

This study aims to investigate the literature in product distribution and channel competition. In this study, past work related to the product distribution through different channels is extensively reviewed. Based on the channel differentiation, channel competition is also reviewed. Finally, the study proposes that the future research may focus on helping the producer make a decision whether to sell the product through its own direct channel (online) through a physical channel or both based on the difference between these two channels.

Validatie van de Nederlandstalige Core Self-evaluations vragenlijst

2007 ◽  
Vol 20 (1) ◽  
Author(s):  
Irene E. de Pater ◽  
Sonja Schinkel ◽  
Bernard A. Nijstad
Keyword(s):  
Work Performance ◽  
Reliability And Validity ◽  
Psychological Research ◽  
Work Outcomes ◽  
Important Work ◽  
Dutch Version ◽  
Total N ◽  
Work Related ◽  
Convergent And Divergent Validity ◽  
Core Self

Validation of the Dutch Core Self-evaluations Scale Validation of the Dutch Core Self-evaluations Scale I.E. de Pater, S. Schinkel & B.A. Nijstad, Gedrag & Organisatie, volume 20, maart 2007, nr. 1, pp. 82-100 In this article we investigated the reliability and validity of the Dutch version of the Core Self-evaluations scale (CSES, Judge, Erez, Bono & Thoresen, 2003). Research into the English version has shown that CSE is a valid construct, consistently correlating with important work related criteria such as work satisfaction and work performance. Because of the relevance of these findings, we developed a Dutch version of this scale (NCSES). Results from four different studies (total N = 1389) showed that the NCSES is internally consistent, has a high test-retest reliability and has the predicted factor structure. Additionally, the convergent and divergent validity of the NCSES are high, and the NCSES correlates with important work outcomes, such job characteristics, job performance, and affective outcomes. It can be concluded that the NCSES is a valuable and effective instrument for applied psychological research.

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