The laser altimeter loaded on the GaoFen-7(GF-7)satellite is designed to record the full waveform data and footprint image,which can obtain high-precision elevation control points for stereo image.The footprint camera...The laser altimeter loaded on the GaoFen-7(GF-7)satellite is designed to record the full waveform data and footprint image,which can obtain high-precision elevation control points for stereo image.The footprint camera equipped on the GF-7 laser altimetry system can capture the energy distribution at the time of laser emission and the image of the ground object where the laser falls,which can be used to judge whether the laser is affected by the cloud.At the same time,the centroid of laser spot on the footprint image can be extracted to monitor the change of laser pointing stability.In this manuscript,a data quality analysis scheme of laser altimetry based on footprint image is presented.Firstly,the cloud detection of footprint image is realized based on deep learning.The fusion result of the model is about 5%better than that of the traditional cloud detection algorithm,which can quickly and accurately determine whether the laser spot is affected by cloud.Secondly,according to the characteristics of footprint image,a threshold constrained ellipse fitting method for extracting the centroid of laser spot is proposed to monitor the pointing stability of long-period lasers.Based on the above method,the change of laser spot centroid since GF-7 satellite was put into operation is analyzed,and the conclusions obtained have certain reference significance for the quality control of satellite laser altimetry data and the analysis of pointing angle stability.展开更多
The correlation between quarter-point angle of elastic scattering and nuclear matter radius is studied systematically.Various phenomenological formulae with parameters for nuclear radius are adopted and compared by fi...The correlation between quarter-point angle of elastic scattering and nuclear matter radius is studied systematically.Various phenomenological formulae with parameters for nuclear radius are adopted and compared by fitting the experimental data of quarter point angle extracted from nuclear elastic scattering reaction systems.A parameterized formula related to binding energy is recommended,which gives a good reproduction of nuclear matter radii of halo nuclei.It indicates that the quarter-point angle of elastic scattering is quite sensitive to the nuclear matter radius and can be used to extract the nuclear matter radius.展开更多
基金National Nature Science Foundation(Nos.41971425,41601505)Special Fund for High Resolution Images Surveying and Mapping Application System(No.42-Y30B04-9001-19/21)。
文摘The laser altimeter loaded on the GaoFen-7(GF-7)satellite is designed to record the full waveform data and footprint image,which can obtain high-precision elevation control points for stereo image.The footprint camera equipped on the GF-7 laser altimetry system can capture the energy distribution at the time of laser emission and the image of the ground object where the laser falls,which can be used to judge whether the laser is affected by the cloud.At the same time,the centroid of laser spot on the footprint image can be extracted to monitor the change of laser pointing stability.In this manuscript,a data quality analysis scheme of laser altimetry based on footprint image is presented.Firstly,the cloud detection of footprint image is realized based on deep learning.The fusion result of the model is about 5%better than that of the traditional cloud detection algorithm,which can quickly and accurately determine whether the laser spot is affected by cloud.Secondly,according to the characteristics of footprint image,a threshold constrained ellipse fitting method for extracting the centroid of laser spot is proposed to monitor the pointing stability of long-period lasers.Based on the above method,the change of laser spot centroid since GF-7 satellite was put into operation is analyzed,and the conclusions obtained have certain reference significance for the quality control of satellite laser altimetry data and the analysis of pointing angle stability.
基金Supported by National Natural Science Foundation of China(U1432247,11575256)National Basic Research Program of Chin(973 Program)(2014CB845405 and 2013CB83440x)(SM)Chinese Academy of Sciences President’s International Fellowship Initiativ(2015-FX-04)
文摘The correlation between quarter-point angle of elastic scattering and nuclear matter radius is studied systematically.Various phenomenological formulae with parameters for nuclear radius are adopted and compared by fitting the experimental data of quarter point angle extracted from nuclear elastic scattering reaction systems.A parameterized formula related to binding energy is recommended,which gives a good reproduction of nuclear matter radii of halo nuclei.It indicates that the quarter-point angle of elastic scattering is quite sensitive to the nuclear matter radius and can be used to extract the nuclear matter radius.
