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绝缘子放电区段划分及污秽预测的泄漏电流分形维数研究 被引量:15
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作者 陈伟根 夏青 +1 位作者 孙才新 李立浧 《中国电机工程学报》 EI CSCD 北大核心 2011年第13期121-127,共7页
污秽放电的极端结果是污闪,为提取反映绝缘子污秽放电发展的有效特征量,在实验室反复试验研究的基础上,利用分形理论中的变换法提取绝缘子污秽放电过程中泄漏电流波形的分形维数,分析不同污秽度下安全区、预报区和危险区3个区段内泄漏... 污秽放电的极端结果是污闪,为提取反映绝缘子污秽放电发展的有效特征量,在实验室反复试验研究的基础上,利用分形理论中的变换法提取绝缘子污秽放电过程中泄漏电流波形的分形维数,分析不同污秽度下安全区、预报区和危险区3个区段内泄漏电流分形维数的差异,提取预报区分形维数的均值和标准差来预测污秽度。得出污秽放电不同阶段分形维数的变化特征明显,且不同污秽度的分形维数大小不同。试验证明泄漏电流分形维数的变化规律能有效预测污秽放电发展趋势及污闪的发生,分形维数的大小能有效判断绝缘子污秽的轻重,为污闪预警提供了新方法和新特征量。 展开更多
关键词 泄漏电流 分形变换法 形维数 污秽度 污秽放电区段
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Traffic sign recognition algorithm based on shape signature and dual-tree complex wavelet transform 被引量:8
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作者 蔡自兴 谷明琴 《Journal of Central South University》 SCIE EI CAS 2013年第2期433-439,共7页
A novel traffic sign recognition system is presented in this work. Firstly, the color segmentation and shape classifier based on signature feature of region are used to detect traffic signs in input video sequences. S... A novel traffic sign recognition system is presented in this work. Firstly, the color segmentation and shape classifier based on signature feature of region are used to detect traffic signs in input video sequences. Secondly, traffic sign color-image is preprocessed with gray scaling, and normalized to 64×64 size. Then, image features could be obtained by four levels DT-CWT images. Thirdly, 2DICA and nearest neighbor classifier are united to recognize traffic signs. The whole recognition algorithm is implemented for classification of 50 categories of traffic signs and its recognition accuracy reaches 90%. Comparing image representation DT-CWT with the well-established image representation like template, Gabor, and 2DICA with feature selection techniques such as PCA, LPP, 2DPCA at the same time, the results show that combination method of DT-CWT and 2DICA is useful in traffic signs recognition. Experimental results indicate that the proposed algorithm is robust, effective and accurate. 展开更多
关键词 traffic sign recognition SIGNATURE DT-CWT 2DICA nearest neighbor classifier
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