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太阳光特定波段光强快速检测方法研究
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作者 张海辉 梁岩 +3 位作者 胡瑾 刘正道 周庆珍 樊宏攀 《光子学报》 EI CAS CSCD 北大核心 2013年第12期1501-1506,共6页
太阳光中各光质对植物光合和生理调节效果不同,分波段光强检测是设施农业高效补光的基础.针对现有特定波段光强检测仪器存在价格高及不易扩展等缺点,提出一种新型定波段光照快速检测方法.以红、蓝光为例,通过实验测量计算不同太阳高度... 太阳光中各光质对植物光合和生理调节效果不同,分波段光强检测是设施农业高效补光的基础.针对现有特定波段光强检测仪器存在价格高及不易扩展等缺点,提出一种新型定波段光照快速检测方法.以红、蓝光为例,通过实验测量计算不同太阳高度角下特定波段光强占太阳光的百分比,并采用Matlab运用最小二乘法进行函数拟合,融合太阳高度角计算公式,建立了特定波段光强在太阳光所占百分比与日期、时间、经度及纬度四个参量之间的多参量耦合模型,通过实时检测太阳光光强快速计算了特定波段光强值.实验证明本方法测量误差小于4.5%,可满足补光系统分波段光强检测需求. 展开更多
关键词 光谱分析 光谱学 多参量耦合模型 太阳光 太阳高度角 定波段 最小二乘法 Matlab
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风云三号A星中分辨率光谱成像仪反射太阳波段辐射定标 被引量:9
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作者 胡秀清 孙凌 +6 位作者 刘京晶 丁雷 王向华 李元 张勇 徐娜 陈林 《气象科技进展》 2013年第4期71-83,共13页
中分辨率光谱成像仪(MERSI)是搭载在我国第二代极轨气象卫星风云三号(FY-3)上的一个主要仪器。总结了MERSI在仪器设计、定标算法、发射前及在轨性能以及仪器性能验证等方面的信息。针对MERISI可见光星上定标器(VOC)的跟踪监测发现,在过... 中分辨率光谱成像仪(MERSI)是搭载在我国第二代极轨气象卫星风云三号(FY-3)上的一个主要仪器。总结了MERSI在仪器设计、定标算法、发射前及在轨性能以及仪器性能验证等方面的信息。针对MERISI可见光星上定标器(VOC)的跟踪监测发现,在过去两年,它的太阳反射波段(RSBs)发生了显著的衰减,特别是较短波长通道(<500nm)衰减量超过10%,最大衰减发生在第8波段,约20%。但波长较长通道的性能相对稳定,衰减量小于5%。两个短波红外通道电子增益出现随机跃动,导致发射后的定标系数存在频繁波动。以上结果与其他两种替代定标方法相比(即中国遥感卫星辐射校正场定标,简称场地定标和基于Terra/MODIS敦煌沙漠场景交叉定标),结论一致。MERSI针对大气顶辐射亮度或反射率定标的总不确定度小于5%。定标结果为FY-3A/MERSI定标系数的更新提供了重要的参考和评估。 展开更多
关键词 衰减率 仪器性能跟踪 中分辨率光谱成像仪 反射太阳波段 替代
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基于透射光谱的苹果霉心病多因子无损检测 被引量:10
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作者 苏东 张海辉 +3 位作者 陈克涛 胡瑾 张佐经 雷雨 《食品科学》 EI CAS CSCD 北大核心 2016年第8期207-211,共5页
针对目前苹果霉心病难以检测的问题,提出一种基于透射光谱的苹果霉心病多因子无损检测方法,通过融合多波段透射光谱与苹果直径,构建苹果霉心病判别模型,实现了苹果霉心病无损检测。搭建光谱测试范围在200~1?025?nm的透射光谱采集平台... 针对目前苹果霉心病难以检测的问题,提出一种基于透射光谱的苹果霉心病多因子无损检测方法,通过融合多波段透射光谱与苹果直径,构建苹果霉心病判别模型,实现了苹果霉心病无损检测。搭建光谱测试范围在200~1?025?nm的透射光谱采集平台,实验获取232个苹果样本的透射光谱数据,采用游标卡尺获得苹果直径数据。采用杂散光校正,非线性校正对苹果透射原始光谱进行预处理,选取与霉心病发病相关的12个波段透射光强值,结合苹果的直径进行主成分分析,将分析的结果作为自变量,建立苹果霉心病Fisher判别模型。经过异校验验证,模型总体识别率为93.1%,而仅采用透射光谱构建的模型识别率为91.37%。结果表明,基于透射光谱与直径结合的多因子检测方法可实现苹果霉心病的准确判定,为苹果霉心病的快速、无损检测提供可行思路。 展开更多
关键词 苹果霉心病 定波段 透射光谱 无损检测 主成分分析 FISHER判别
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Response of fuzzy clustering on different threshold determination algorithms in spectral change vector analysis over Western Himalaya, India 被引量:2
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作者 SINGH Sartajvir TALWAR Rajneesh 《Journal of Mountain Science》 SCIE CSCD 2017年第7期1391-1404,共14页
Abstract: Change detection is a standard tool to extract and analyze the earth's surface features from remotely sensed data. Among the different change detection techniques, change vector analysis (CVA) have an ex... Abstract: Change detection is a standard tool to extract and analyze the earth's surface features from remotely sensed data. Among the different change detection techniques, change vector analysis (CVA) have an exceptional advantage of discriminating change in terms of change magnitude and vector direction from multispectral bands. The estimation of precise threshold is one of the most crucial task in CVA to separate the change pixels from unchanged pixels because overall assessment of change detection method is highly dependent on selected threshold value. In recent years, integration of fuzzy clustering and remotely sensed data have become appropriate and realistic choice for change detection applications. The novelty of the proposed model lies within use of fuzzy maximum likelihood classification (FMLC) as fuzzy clustering in CVA. The FMLC based CVA is implemented using diverse threshold determination algorithms such as double-window flexible pace search (DFPS), interactive trial and error (T&E), and 3x3-pixel kernel window (PKW). Unlike existing CVA techniques, addition of fuzzy clustering in CVA permits each pixel to have multiple class categories and offers ease in threshold determination process. In present work, the comparative analysis has highlighted the performance of FMLC based CVA overimproved SCVA both in terms of accuracy assessment and operational complexity. Among all the examined threshold searching algorithms, FMLC based CVA using DFPS algorithm is found to be the most efficient method. 展开更多
关键词 Change vector analysis (CVA) Fuzzymaximum likelihood classification (FMLC) Double-window flexible pace search (DFPS) Interactive trialand error (T&E) Pixel kernel window (PKW)
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The improvement of cross-calibration of IIM data and band selection for FeO inversion 被引量:4
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作者 WANG Chao WU YunZhao +1 位作者 SHI RunHe GAO Wei 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第11期2216-2225,共10页
Chang’E-1(CE-1)Interference Imaging Spectrometer(IIM)dataset suffers from the weak response in the near infrared(NIR)bands,which are the important wavelength for retrieving the minerals and elements of the Moon.In th... Chang’E-1(CE-1)Interference Imaging Spectrometer(IIM)dataset suffers from the weak response in the near infrared(NIR)bands,which are the important wavelength for retrieving the minerals and elements of the Moon.In this paper,the cross-calibration was implemented to the IIM hyperspectral data for improving the weak response in NIR bands.The results show that the cross-calibrated IIM spectra were consistent to the Earth-based telescopic spectra,which suggests that the cross-calibration yields acceptable results.For further validating the influence of the cross-calibration on the FeO inversion and searching the optimal bands to retrieve lunar FeO contents,four band selection schemes were designed to retrieve FeO using the original and cross-calibrated IIM spectra.By comparing the distribution patterns and histograms of the IIM derived FeO contents with the Clementine derived FeO,the IIM 891 nm band after cross-calibration showed a higher accuracy in the FeO inversion,hence most useful for lunar FeO inversion. 展开更多
关键词 IIM CROSS-CALIBRATION band selection FEO MOON
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