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基于场量提取法的电磁层析成像系统的灵敏度推算 被引量:17
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作者 徐凯 陈广 +1 位作者 尹武良 王化祥 《传感技术学报》 CAS CSCD 北大核心 2011年第4期543-547,共5页
电磁层析成像技术(EMT)是一种新型的电学层析成像技术,它通过测量激励和接受线圈之间的互感变化而实现物场区域内电导率和磁导率分布的图像重建。灵敏度的计算是电磁层析成像技术的关键环节,是图像重建的必备条件,灵敏度计算的准确性直... 电磁层析成像技术(EMT)是一种新型的电学层析成像技术,它通过测量激励和接受线圈之间的互感变化而实现物场区域内电导率和磁导率分布的图像重建。灵敏度的计算是电磁层析成像技术的关键环节,是图像重建的必备条件,灵敏度计算的准确性直接影响到最终的成像精度。采用场量提取的方法计算了EMT系统的灵敏度。理论上,首次完整地推导出了EMT灵敏度的数学表达式。仿真计算上,借助MATLAB软件分别实现了电导率和磁导率灵敏度的独立计算,并依次绘制了相应的灵敏度图,为精确图像重建算法提供了有利条件。 展开更多
关键词 电磁层析成像技术 灵敏度 场量提取 电导率 磁导率
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Classification of underwater still objects based on multi-field features and SVM 被引量:4
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作者 TIAN Jie XUE Shan-hua HUANG Hai-ning ZHANG Chun-hua 《Journal of Marine Science and Application》 2007年第1期36-40,共5页
A Support Vector Machine is used as a classifier to the automatic detection and recognition of underwater still objects. Discrimination between the objects can be transferred into different projection spaces by the pr... A Support Vector Machine is used as a classifier to the automatic detection and recognition of underwater still objects. Discrimination between the objects can be transferred into different projection spaces by the process of multi-field feature extraction. The multi-field feature vector includes time-domain, spectral, time-frequency distribution and bi-spectral features. Underwater target recognition can be considered as a problem of small sample recognition. SVM algorithm is appropriate to this kind of problems because of its outstanding generalizability. The SVM is contrasted with a Gaussian classifier and a k-nearest classifier in some experiments using real data of lake or sea trial. The experimental results indicate that SVM is better than the others two. 展开更多
关键词 underwater still objects CLASSIFICATION feature support vector machine (SVM)
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Fingerprint singular points extraction based on orientation tensor field and Laurent series 被引量:3
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作者 刘琴 彭可 +4 位作者 刘巍 谢琴 李仲阳 兰浩 金耀 《Journal of Central South University》 SCIE EI CAS 2014年第5期1927-1934,共8页
Singular point(SP)extraction is a key component in automatic fingerprint identification system(AFIS).A new method was proposed for fingerprint singular points extraction,based on orientation tensor field and Laurent s... Singular point(SP)extraction is a key component in automatic fingerprint identification system(AFIS).A new method was proposed for fingerprint singular points extraction,based on orientation tensor field and Laurent series.First,fingerprint orientation flow field was obtained,using the gradient of fingerprint image.With these gradients,fingerprint orientation tensor field was calculated.Then,candidate SPs were detected by the cross-correlation energy in multi-scale Gaussian space.The energy was calculated between fingerprint orientation tensor field and Laurent polynomial model.As a global descriptor,the Laurent polynomial coefficients were allowed for rotational invariance.Furthermore,a support vector machine(SVM)classifier was trained to remove spurious SPs,using cross-correlation coefficient as a feature vector.Finally,experiments were performed on Singular Point Detection Competition 2010(SPD2010)database.Compared to the winner algorithm of SPD2010 which has best accuracy of 31.90%,the accuracy of proposed algorithm is 45.34%.The results show that the proposed method outperforms the state-of-the-art detection algorithms by large margin,and the detection is invariant to rotational transformations. 展开更多
关键词 fingerprint extraction singular point fingerprint orientation tensor field Laurent series rotational invariance supportvector machine (SVM)
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