Due to the atmosphere effect,the qualities of images decrease conspicuously,practically in the visible bands,in the processing of earth observation by the satellite-borne sensors.Thus,removing the atmosphere effects h...Due to the atmosphere effect,the qualities of images decrease conspicuously,practically in the visible bands,in the processing of earth observation by the satellite-borne sensors.Thus,removing the atmosphere effects has become a key step to improve the qualities of images and to retrieve the actual reflectivity of surface features.An atmospheric correction approach,called ACVSS(Atmospheric Correction based Vector Space of Spectrum),is proposed here based on the vector space of the features' spectrum.The reflectance image of each band is retrieved first according to the radiative transfer equation,then the spectrum's vector space is constructed using the infrared bands,and finally the residual errors of the reflectance images in the visible bands are corrected based on the pixel position in the spectrum's vector space.The proposed methodology is verified through atmospheric correction on Landsat-7 ETM+ imagery.The experimental results show that our method is more accurate and the corrected image is more distinct,compared with those offered by current popular atmospheric correction software.展开更多
大型旋转机械的转子运动是一空间运动。转子故障在发生或发展时,其运行过程具有明显非平稳特性的瞬态过程。通常针对单通道信息的时频分析并不能全面提取瞬态过程的特征信息。结合空间域矢谱(Vector-spectrum in space-domain)分析和Wig...大型旋转机械的转子运动是一空间运动。转子故障在发生或发展时,其运行过程具有明显非平稳特性的瞬态过程。通常针对单通道信息的时频分析并不能全面提取瞬态过程的特征信息。结合空间域矢谱(Vector-spectrum in space-domain)分析和Wigner-Ville分布(Wigner-Ville Distribution,WVD)技术提出了空间域矢Wigner-Ville分布分析方法。它融合了转子同截面三通道图谱中各自存在的振动分量,能全面、准确地反映转子发生故障时的瞬态过程特征量变化。工程实践应用表明:空间域矢Wigner-Ville分布分析对于旋转机械故障诊断是一种新的、较为实用的信息融合方法。展开更多
基金supported by National High-tech R&D Program (Grant Nos.2011AA120300,2011AA120302)Foster-ing Program of Science and Technology Innovative Platform,Northeast Normal University (Grant No.106111065202)
文摘Due to the atmosphere effect,the qualities of images decrease conspicuously,practically in the visible bands,in the processing of earth observation by the satellite-borne sensors.Thus,removing the atmosphere effects has become a key step to improve the qualities of images and to retrieve the actual reflectivity of surface features.An atmospheric correction approach,called ACVSS(Atmospheric Correction based Vector Space of Spectrum),is proposed here based on the vector space of the features' spectrum.The reflectance image of each band is retrieved first according to the radiative transfer equation,then the spectrum's vector space is constructed using the infrared bands,and finally the residual errors of the reflectance images in the visible bands are corrected based on the pixel position in the spectrum's vector space.The proposed methodology is verified through atmospheric correction on Landsat-7 ETM+ imagery.The experimental results show that our method is more accurate and the corrected image is more distinct,compared with those offered by current popular atmospheric correction software.
文摘大型旋转机械的转子运动是一空间运动。转子故障在发生或发展时,其运行过程具有明显非平稳特性的瞬态过程。通常针对单通道信息的时频分析并不能全面提取瞬态过程的特征信息。结合空间域矢谱(Vector-spectrum in space-domain)分析和Wigner-Ville分布(Wigner-Ville Distribution,WVD)技术提出了空间域矢Wigner-Ville分布分析方法。它融合了转子同截面三通道图谱中各自存在的振动分量,能全面、准确地反映转子发生故障时的瞬态过程特征量变化。工程实践应用表明:空间域矢Wigner-Ville分布分析对于旋转机械故障诊断是一种新的、较为实用的信息融合方法。
