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基于L*a*b*彩色空间和局域动态阈值的药用植物叶片图像分割 被引量:11
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作者 高理文 林小桦 《计算机应用与软件》 CSCD 北大核心 2014年第1期232-235,共4页
叶片图像分割是自动化分类的先决步骤。提出一种基于L*a*b*彩色空间和局域动态阈值的叶片图像分割方法。该方法首先把叶片的RGB图像转换为L*a*b*图像;然后针对b*通道图像,估算出目标叶片所在的局部矩形范围;在此范围内,统计获得像素值... 叶片图像分割是自动化分类的先决步骤。提出一种基于L*a*b*彩色空间和局域动态阈值的叶片图像分割方法。该方法首先把叶片的RGB图像转换为L*a*b*图像;然后针对b*通道图像,估算出目标叶片所在的局部矩形范围;在此范围内,统计获得像素值分布直方图;最后利用最大类间方差阈值分割法,先算出局部矩形范围内的阈值继而进行全图的分割。实验结果表明:该方法对已采集的叶片图像,包括颜色偏暗的叶片的图像,均具有良好的分割效果。由于锁定目标叶片所处的局部矩形范围,找到了适应于目标叶片分割的阈值,从而更好地实现了南天竺等叶片图像的分割。此外,分割过程不包含数学形态学的开闭运算,使得叶片边缘的细节得以完整保留。 展开更多
关键词 L* a* b*空间 动态阈值 叶片 图像分割
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基于L*a*b*空间颜色信息度量的边缘检测 被引量:1
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作者 王菁 赵昭 朱晓媛 《微型机与应用》 2009年第23期25-26,29,共3页
对L*a*b*空间进行分析,提出了一种基于颜色信息度量的边缘检测算法。通过在L*a*b*空间中构造立方体,根据体积变化定义各像素点的颜色信息度量,作为确定各像素点是否为彩色图像的边缘点的判据。该方法综合利用了彩色图像的明度和色度信息... 对L*a*b*空间进行分析,提出了一种基于颜色信息度量的边缘检测算法。通过在L*a*b*空间中构造立方体,根据体积变化定义各像素点的颜色信息度量,作为确定各像素点是否为彩色图像的边缘点的判据。该方法综合利用了彩色图像的明度和色度信息,将向量空间的计算以自然的方式转换成了标量的计算。实验证明,与传统的方法相比较,能快速有效地检测出图像的边缘。 展开更多
关键词 彩色图像 边缘检测 颜色信息度量 L*a*b*空间
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The Growth and 1/4-Theorems for Spirallik Maps in l^P, B^P and Inner Product Space
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作者 刘浩 徐兴辰 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第3期48-52,共5页
The paper is made of two parts.In first part,We give the growth and 1/4-theorems for spiral like maps on the unit ball in l^p.Particularly,corresponding results were given in B^p.In the second part,we give the growth ... The paper is made of two parts.In first part,We give the growth and 1/4-theorems for spiral like maps on the unit ball in l^p.Particularly,corresponding results were given in B^p.In the second part,we give the growth and 1/4-theorems for spirallike maps in an inner product space.We prove that the results is best. 展开更多
关键词 biholomorphic mapping spirallike mapping frechet derivative growth thorem kebe 1/4-thorem
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Notes on well-posedness for the b-family equation
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作者 朱敏 《Journal of Southeast University(English Edition)》 EI CAS 2014年第1期128-134,共7页
The local well-posedness for the b-family equation in the critical space is studied.Applying the Littlewood-Paley decomposition method in the critical Besov spaces Bs2r with the index s=3/2 which is the generalization... The local well-posedness for the b-family equation in the critical space is studied.Applying the Littlewood-Paley decomposition method in the critical Besov spaces Bs2r with the index s=3/2 which is the generalization space of the Sobolev spaces Hs it is established that there is a maximal time T=Tu0&gt;0 such that for the b-family equation there exists a unique solution utx∈C0TB3/221∩C10TB121 when the initial variable u0x ∈B3/221 is the critical regularity. Moreover the solution uxt depends continuously on the initial data u0x .Furthermore using the abstract Cauchy-Kowalevski theorem to prove the analytic regularity of the solutions for the b-family equation in a suitable scale of Banach spaces E it is shown that the solutions of the b-family are analytic in both variables globally in space and locally in time when the initial data is analytic. 展开更多
关键词 b-family equation besov space local well-pos-edness
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On the Cluster Set C [S_n/(2nφ(n))^(1/2)] in 2-type Banach Space
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作者 王新全 田长安 杨长森 《Chinese Quarterly Journal of Mathematics》 CSCD 1999年第2期88-93, ,共6页
Suppose {X,X n,n≥1} are the i.i.d. random variables with values in 2 type Banach space B,S n=∑nk=1X k,φ(x) is a increasing function on [0,+∞), φ(x)→+∞, and φ(x)x is no increasing; then we point out that the cl... Suppose {X,X n,n≥1} are the i.i.d. random variables with values in 2 type Banach space B,S n=∑nk=1X k,φ(x) is a increasing function on [0,+∞), φ(x)→+∞, and φ(x)x is no increasing; then we point out that the cluster set CS n2nφ(n) is ρK, where ρ= lim L 2nφ(n)<+∞, ∫ ∞e -ρ 2φ(x) 1xd x=+∞,X∈WM 2 0, and E‖X‖ 2φ(‖X‖)<+∞. 展开更多
关键词 type space INDEPENDENCE CLUSTER
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Spatial Distribution Characteristic of the b-value in Dabie-Sulu and Its Adjacent Areas
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作者 Wu Pingping Jia Jianpeng 《Earthquake Research in China》 CSCD 2016年第2期253-263,共11页
The Tanlu (Tancheng-Lujiang) fault is one of the major structures in eastern China, which cuts across different blocks and controls the tectonic activity. Using the seismic data from the China Earthquake Networks Ce... The Tanlu (Tancheng-Lujiang) fault is one of the major structures in eastern China, which cuts across different blocks and controls the tectonic activity. Using the seismic data from the China Earthquake Networks Center, we investigate the spatial variations of the b-value in the Dabie-Sulu (Jiangsu-Shandong) organic belt by calculating the b-value of each grid (1~ xl~) from 1970 to 2010. The study shows that: the b-value is smaller in the Tanlu fault and its adjacent area, which might suggest that the major earthquake recurrence period is relatively long due to the lower frequency of small earthquake activity. In both sides of Tanlu fault, the b-value is higher at the edge of Sulu block and the eastern part of Dabie orogenic belt. The b values are higher in North China central orogenic belt, and small earthquake activity which occurred along the central orogenic belt is frequent. Additionally, combined with geological and geophysical study, we find that the b-value has a certain correspondence relationship with the lithologic distribution, which informs us that seismic activity features are closely related to the inhomogeneous media in the crust. 展开更多
关键词 Tanlu(Tancheng-Lujiang) fault b-value Earthquake activity Earthquakefrequency
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Analysis on b-value Abnormality of the Minxian-Zhangxian,Gansu M_S6.6 Earthquake
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作者 Feng Jiangang Zhang Hui Yang Ping 《Earthquake Research in China》 CSCD 2016年第2期186-192,共7页
In this paper,based on Gansu Digital Seismic Network data since 1990,we calculated b-value and ⊿ b-value of the neighborhood area before the 2013 Minxian-Zhangxian M_S6. 6,earthquake. The results show that the earthq... In this paper,based on Gansu Digital Seismic Network data since 1990,we calculated b-value and ⊿ b-value of the neighborhood area before the 2013 Minxian-Zhangxian M_S6. 6,earthquake. The results show that the earthquake occurred at the margin of the significantly lower b-value area in southeast of Gansu and before the earthquake the neighborhood area had an obviously abnormal ⊿ b-value. From the earthquake and the spatial distribution of low b-value, the region still has the possibility of generating dangerous strong earthquakes. 展开更多
关键词 Minxian-Zhangxian earthquake b-value Southeastern Gansu
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基于机器视觉的蔬菜生长状况分析 被引量:7
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作者 豆东东 陈广锋 《中国农机化学报》 2016年第10期162-165,共4页
蔬菜植株面积大小是评估其生长状况的重要依据。本文采用基于机器视觉的图像处理技术,获取并分析蔬菜的生长状况,其关键在于如何准确地分割图像并计算叶面积大小。为此,通过对采用传统的阈值分割算法、传统的K-means分割算法和L*a*b*空... 蔬菜植株面积大小是评估其生长状况的重要依据。本文采用基于机器视觉的图像处理技术,获取并分析蔬菜的生长状况,其关键在于如何准确地分割图像并计算叶面积大小。为此,通过对采用传统的阈值分割算法、传统的K-means分割算法和L*a*b*空间下的K-means分割算法所输出结果的对比分析,结果表明在L*a*b*空间下进行的K-means分割,在保留蔬菜叶片表面信息的同时不仅有效地分割图像,而且能以彩色图像的形式输出。本文选取了30株绿色蔬菜,计算其在第15天、30天、45天的叶面积大小,通过对比同一蔬菜在不同时间与同一时间及同期内不同蔬菜的叶面积,评估得到这30株蔬菜的生长状况。 展开更多
关键词 生长状况 阈值分割 L*a*b*空间 K-MEANS聚类 叶面积计算
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Classification of EEG-based single-trial motor imagery tasks using a B-CSP method for BCI 被引量:5
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作者 Zhi-chuan TANG Chao LI +2 位作者 Jian-feng WU Peng-cheng LIU Shi-wei CHENG 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2019年第8期1087-1099,共13页
Classifying single-trial electroencephalogram(EEG)based motor imagery(MI)tasks is extensively used to control brain-computer interface(BCI)applications,as a communication bridge between humans and computers.However,th... Classifying single-trial electroencephalogram(EEG)based motor imagery(MI)tasks is extensively used to control brain-computer interface(BCI)applications,as a communication bridge between humans and computers.However,the low signal-to-noise ratio and individual differences of EEG can affect the classification results negatively.In this paper,we propose an improved common spatial pattern(B-CSP)method to extract features for alleviating these adverse effects.First,for different subjects,the method of Bhattacharyya distance is used to select the optimal frequency band of each electrode including strong event-related desynchronization(ERD)and event-related synchronization(ERS)patterns;then the signals of the optimal frequency band are decomposed into spatial patterns,and the features that can describe the maximum differences of two classes of MI are extracted from the EEG data.The proposed method is applied to the public data set and experimental data set to extract features which are input into a back propagation neural network(BPNN)classifier to classify single-trial MI EEG.Another two conventional feature extraction methods,original common spatial pattern(CSP)and autoregressive(AR),are used for comparison.An improved classification performance for both data sets(public data set:91.25%±1.77%for left hand vs.foot and84.50%±5.42%for left hand vs.right hand;experimental data set:90.43%±4.26%for left hand vs.foot)verifies the advantages of the B-CSP method over conventional methods.The results demonstrate that our proposed B-CSP method can classify EEG-based MI tasks effectively,and this study provides practical and theoretical approaches to BCI applications. 展开更多
关键词 Electroencephalogram(EEG) Motor imagery(MI) Improved common spatial pattern(b-CSP) Feature extraction CLASSIFICATION
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LIL behavior for B-valued strong mixing random variables 被引量:1
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作者 FU KeAng ZHANG LiXin 《Science China Mathematics》 SCIE 2011年第4期785-792,共8页
Given a sequence of mixing random variables {X1,Xn;n≥1} taking values in a separable Banach space B,and Sn denoting the partial sum,a general law of the iterated logarithm is established,that is,we have with probabil... Given a sequence of mixing random variables {X1,Xn;n≥1} taking values in a separable Banach space B,and Sn denoting the partial sum,a general law of the iterated logarithm is established,that is,we have with probability one,lim supn→∞‖Sn‖/cn = α0 < ∞ for a regular normalizing sequence {cn}1,where α 0 is a precise value. 展开更多
关键词 law of the iterated logarithm(LIL) φ*-mixing banach space of type p
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