The emulsification of crude oil is caused by the oil flowing into the water,resulting in the increase of oil film tension,viscosity,water content,and volume,which brings great harm to the marine ecological environment...The emulsification of crude oil is caused by the oil flowing into the water,resulting in the increase of oil film tension,viscosity,water content,and volume,which brings great harm to the marine ecological environment and difficulties for the cleanup of marine emergency equipment.The realization observation of emulsification crude oil will increase the response speed of marine emergency response.Therefore,we set up crude oil emulsification samples to study the physical property in laboratory and conducted radar measurements at different incidence angles in outdoor.The radar is C band in resolution of 0.7 m by 0.7 m.A fully polarimetric scatterometer(HH,VV,and VH/HV)is mounted at 1.66 m(minimum altitude)height at an incidence angle between 35°and 60°.An asphalt content of less than 3%crude oil and the filtered seawater were used to the outdoor emulsification scattering experiment.The measurement results are as follows.The water content can be used to describe the process of emulsification and it is easy to measure.Wind speed,asphalt content,seawater temperature,and photo-oxidation affect the emulsifying process of crude oil,and affects the normalized radar cross section(NRCS)of oil film but wind is not the dominant factor.It is the first time to find that the emulsification of crude oil results in an increase of NRCS.展开更多
Each reflection return of a bridge over water is displayed as wide stripe in a high-resolution synthetic aperture radar （SAR） image, which lead to difficulties in a parameter inversion. Therefore, a method of bridge...Each reflection return of a bridge over water is displayed as wide stripe in a high-resolution synthetic aperture radar （SAR） image, which lead to difficulties in a parameter inversion. Therefore, a method of bridge parameter inversion is proposed for high-resolution full polarimetric SAR （PolSAR）. First, the single, double and triple- bounce returns from each component of the bridge are distinguished by the polarization scattering features. Then the reasons which lead to the backscatter echoes oft_he bridge over water being displayed as stripes are analyzed, using a principle of microwave reflection, as well as an extraction method for each reflection return, and a parameter retrieval method is obtained. Finally, the parameters of the bridge, including the height （top and bottom surfaces of the sea bridge）, width, thickness, span, and height of the bridge tower, are retrieved using full polarimetric AIRSAR data. When a comparison of the measured data is completed, the results indicate that the proposed method can invert the parameters with a high accuracy, and that the inversion error of the bridge height （bottom surface） is only 1.3%. Moreover, the results also show that for the high-resolution SAR, the C and L-band images have the same ability in regards to parameter retrieval.展开更多
文摘多时相合成孔径雷达(SAR)卫星数据的组合能有效缩短重访周期、提高船只目标匹配跟踪能力,但多时相SAR工作参数(波段、分辨率等)、船只特点(尺寸小、常处于运动等)均会影响匹配跟踪方法的精度与效率。因此,将Harris方法、FAST(Features from Accelerated Segment Test)方法、尺度不变特征转换(SIFT)方法和SAR尺度不变特征转换(SAR-SIFT)这4种匹配方法应用至多时相SAR船只目标,从抗噪性、描述目标能力以及特征点稳定性三方面综合评估各方法的性能。在抗噪性方面,SAR-SIFT、FAST和Harris方法均未检测到海洋背景的干扰特征点;在描述目标能力方面,SAR-SIFT方法提取的特征点数比其他方法高出15%,并且特征点分布均匀;在特征点稳定性方面,SAR-SIFT方法的同名特征点重复检测率比其他方法高10%以上。实验结果表明,SAR-SIFT方法在多时相SAR船只目标特征点提取匹配中更具优势。
基金Supported by the National Natural Science Foundation of China(No.41576032)the Major Program for the International Cooperation of the Chinese Academy of Sciences,China(No.133337KYSB20160002)partially supported by the National Natural Science Foundation of China(Nos.41576170,61371189)
文摘The emulsification of crude oil is caused by the oil flowing into the water,resulting in the increase of oil film tension,viscosity,water content,and volume,which brings great harm to the marine ecological environment and difficulties for the cleanup of marine emergency equipment.The realization observation of emulsification crude oil will increase the response speed of marine emergency response.Therefore,we set up crude oil emulsification samples to study the physical property in laboratory and conducted radar measurements at different incidence angles in outdoor.The radar is C band in resolution of 0.7 m by 0.7 m.A fully polarimetric scatterometer(HH,VV,and VH/HV)is mounted at 1.66 m(minimum altitude)height at an incidence angle between 35°and 60°.An asphalt content of less than 3%crude oil and the filtered seawater were used to the outdoor emulsification scattering experiment.The measurement results are as follows.The water content can be used to describe the process of emulsification and it is easy to measure.Wind speed,asphalt content,seawater temperature,and photo-oxidation affect the emulsifying process of crude oil,and affects the normalized radar cross section(NRCS)of oil film but wind is not the dominant factor.It is the first time to find that the emulsification of crude oil results in an increase of NRCS.
基金The Public Science and Technology Research Funds Projects of Ocean under contract No.201505002
文摘Each reflection return of a bridge over water is displayed as wide stripe in a high-resolution synthetic aperture radar （SAR） image, which lead to difficulties in a parameter inversion. Therefore, a method of bridge parameter inversion is proposed for high-resolution full polarimetric SAR （PolSAR）. First, the single, double and triple- bounce returns from each component of the bridge are distinguished by the polarization scattering features. Then the reasons which lead to the backscatter echoes oft_he bridge over water being displayed as stripes are analyzed, using a principle of microwave reflection, as well as an extraction method for each reflection return, and a parameter retrieval method is obtained. Finally, the parameters of the bridge, including the height （top and bottom surfaces of the sea bridge）, width, thickness, span, and height of the bridge tower, are retrieved using full polarimetric AIRSAR data. When a comparison of the measured data is completed, the results indicate that the proposed method can invert the parameters with a high accuracy, and that the inversion error of the bridge height （bottom surface） is only 1.3%. Moreover, the results also show that for the high-resolution SAR, the C and L-band images have the same ability in regards to parameter retrieval.
