The Experts below are selected from a list of 168504 Experts worldwide ranked by ideXlab platform
Yayun Cheng - One of the best experts on this subject based on the ideXlab platform.
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Multi-polarization passive millimeter-wave imager and outdoor scene imaging analysis for remote sensing applications
Optics express, 2018Co-Authors: Yayun ChengAbstract:Polarimetric passive millimeter-wave (PMMW) measurements can provide additional information about scenes. We report on the development of a 94GHz Multi-Polarization Scanning Imaging Radiometer (MPSIR) for outdoor imaging applications, and the polarization characteristic analysis of experimentally acquired images. The imager angular resolution is measured to be 0.37°, and the thermal sensitivity is about 0.46K. Multi-polarization measurements are realized by rotating the detector around the observation axis direction. Several outdoor complex scenes are selected to passive image, which include the outdoor parking lot and the dormitory buildings in the woods. Various polarization parameter images are generated to analyze the polarization characteristics. Based on the multi-polarization imaging, eight more polarization parameters are created and they are all have the Special Distribution properties. The experimental results indicate that the multi-polarization imaging and the modified polarization parameters have the great potential for three-dimensional reconstruction, edge detection and image segmentation.
Jun Chen - One of the best experts on this subject based on the ideXlab platform.
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an approach to cross calibrating multi mission satellite data for the open ocean
Remote Sensing of Environment, 2020Co-Authors: Jun Chen, Zhongli Liu, Qianguo Xing, Delu PanAbstract:Abstract Synchronous observations with similar illumination-observation and meteorological conditions are critical components of cross-calibration analysis. This study outlines data quality control criteria for obtaining the stable synchronous data needed for developing and evaluating a cross-calibration algorithm. With image data from the Visible Infrared Imaging Radiometer (VIIRS) and Medium Resolution Spectral Imager II (MERSI II), we developed a cross-calibration algorithm using 35 image pairs of four ocean gyres, and we evaluated the data using 11 image pairs of the global ocean. We found that our new algorithm provided well-calibrated MERSI II reflectance at the top-of-atmosphere. The coefficients of determination (R2) were greater than 0.89, and the mean absolute percent difference (MAPD) varied from 1.13% to 8.37% in the visible bands, which was significantly superior to an algorithm developed from a data set constrained by existing data quality controls. When the satellite data were preprocessed with the new cross-calibration algorithm, the MERSI II instrument provided inter-mission remote sensing reflectance for the North Pacific Gyre that was consistent with the VIIRS instrument. Furthermore, we derived consistent estimates of remote sensing reflectance and backscattering coefficients (bb) from VIIRS and the cross-calibrated MERSI II reflectance data for four typically turbid coastal waters. The VIIRS bb coastal images had Special Distribution patterns, such as tongue-shaped plumes and mesoscale eddies, which accurately reappeared in the MERSI II images. The inter-mission MAPD values varied from 16%–24% for the coastal waters. This uncertainty level was much lower than the bb data quantified from the original MERSI II data with no cross-calibration. Our results suggest that our data quality control criteria provide good quality synchronous data for cross-calibration analysis. MERSI II could provide good ocean color products for oceanic communications after cross-calibration, even though the radiance calibration for the original MERSI II reflectance data are imperfect.
Shuai Yao - One of the best experts on this subject based on the ideXlab platform.
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spatiotemporal evolution characteristics of china s cold chain logistics resources and agricultural product using remote sensing perspective
European Journal of Remote Sensing, 2021Co-Authors: Yajuan Zhang, Shuai YaoAbstract:The cold chain logistics is a Special Distribution process with respect to agricultural products that are sensitive to temperature. In this approach, remote sensing data and spatial analysis are th...
Delu Pan - One of the best experts on this subject based on the ideXlab platform.
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an approach to cross calibrating multi mission satellite data for the open ocean
Remote Sensing of Environment, 2020Co-Authors: Jun Chen, Zhongli Liu, Qianguo Xing, Delu PanAbstract:Abstract Synchronous observations with similar illumination-observation and meteorological conditions are critical components of cross-calibration analysis. This study outlines data quality control criteria for obtaining the stable synchronous data needed for developing and evaluating a cross-calibration algorithm. With image data from the Visible Infrared Imaging Radiometer (VIIRS) and Medium Resolution Spectral Imager II (MERSI II), we developed a cross-calibration algorithm using 35 image pairs of four ocean gyres, and we evaluated the data using 11 image pairs of the global ocean. We found that our new algorithm provided well-calibrated MERSI II reflectance at the top-of-atmosphere. The coefficients of determination (R2) were greater than 0.89, and the mean absolute percent difference (MAPD) varied from 1.13% to 8.37% in the visible bands, which was significantly superior to an algorithm developed from a data set constrained by existing data quality controls. When the satellite data were preprocessed with the new cross-calibration algorithm, the MERSI II instrument provided inter-mission remote sensing reflectance for the North Pacific Gyre that was consistent with the VIIRS instrument. Furthermore, we derived consistent estimates of remote sensing reflectance and backscattering coefficients (bb) from VIIRS and the cross-calibrated MERSI II reflectance data for four typically turbid coastal waters. The VIIRS bb coastal images had Special Distribution patterns, such as tongue-shaped plumes and mesoscale eddies, which accurately reappeared in the MERSI II images. The inter-mission MAPD values varied from 16%–24% for the coastal waters. This uncertainty level was much lower than the bb data quantified from the original MERSI II data with no cross-calibration. Our results suggest that our data quality control criteria provide good quality synchronous data for cross-calibration analysis. MERSI II could provide good ocean color products for oceanic communications after cross-calibration, even though the radiance calibration for the original MERSI II reflectance data are imperfect.
Chen Xiaofei - One of the best experts on this subject based on the ideXlab platform.
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point source stacking method to compute synthetic seismogram of finite moving planar source
Acta Scientiarum Naturalium Universitatis Pekinensis, 2007Co-Authors: Chen XiaofeiAbstract:The kinematical finite source is considered as stacking of dynamic point sources based on the dynamic independent principle.The stacking has two means,the stacking of the area of sources and the stacking of the kinematical process.Following this idea,the authors showed different discretizing method and rise time for different propagating models of the finite source.The stacking method is validated by comparing with analytical results.The relationship between the critical value and rise time,Special Distribution of stations,crack propagating velocity for a strike-slip fault in a two-layer earth model are further discussed.The analysis shows that to keep the precision of the synthetic seismograms,the critical areas vary with the rupture speed,frequency of the source time function and the position of the stations.The results could be the valuable reference for the discritizing the planar element in strong ground motion simulation and near source inversion.