共查询到20条相似文献，搜索用时 484 毫秒
1.
分析了现有断层建模技术,提出了基于局部克里金插值算法的横断层自动分析和显示技术。算法通过搜索遍历钻孔点计算模型的有效区域和阈值,选用基于面模型的网格三角化法构建地质体,结合OpenGL实现了三维构建和漫游。实验证明,该方法能够实现横断层的自动分析和显示。 相似文献
2.
热成像过程中热成像重复量化和反差增强导致伪轮廓,需要对热成像伪轮廓进行掩模处理,以消除图像伪轮廓瑕疵,提高热成像的识别性能。热成像图像噪点具有非平稳性,对其进行伪轮廓消除和掩模处理较为困难。提出一种基于4通道扇形滤波的热成像伪轮廓掩模处理技术。首先采用改进的基于量化误差补偿的伪轮廓掩模矢量量化方法对热成像进行预处理,设计点到线模型,进行伪轮廓边缘检测和掩模矢量量化算法改进,设计4通道扇形滤波滤除伪轮廓瑕疵点,改进伪轮廓掩模算法。实验结果表明,该算法能有效实现对热成像的伪轮廓掩模处理,提高对热成像的识别精度。 相似文献
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4.
针对传统配准方法存在配准精度低的问题,提出一种新的弹性配准插值算法。新方法基于B样条的自由变形模型,将最大互信息准则作为形变图像与目标图像的相似性测度对相邻的片层图像进行配准。然后,提出一种改进的双线性插值方法,通过构造插值点的最小环绕四边形计算该插值点的值,从而得到最终的插值图像。 相似文献
5.
《科技通报》2016,(5)
提出了一种基于双目立体视觉的玉米叶片三维重建方法。该方法利用两个平行且位置相对固定的摄像机,组成双目立体视觉系统。运用改进的张正友平面标定法进行摄像机标定,采用一种改进的Harris算法,通过快速预筛选和多阈值角点提取方法,对获取的图像采集Harris角点以提取玉米叶片特征,通过计算搜索窗口内对应点的相关系数和阈值的比较实现特征点匹配,依据视差原理,计算得到玉米叶片的三维点云信息,对预处理后的玉米叶片点云进行双三次B样条曲线插值,重构叶片的三维网格曲面。仿真实验表明:所提方法能够高效、准确地实现玉米叶片三维重建,对玉米叶片边缘起伏和褶皱等细节可完整保留,三维重建精度较高。 相似文献
6.
基于机载LiDAR数据的建筑屋顶点云提取方法 总被引：1，自引：0，他引：1
机载激光雷达技术已经成为快速获取城市建筑三维数字模型的有效手段,而建筑物屋顶点云提取则是建筑物三维数字模型重建的关键.为有效剔除植被和墙面点云,以及消除地形起伏对建筑点云提取精度的影响,提出一种层进式屋顶点云提取方法.首先对Li DAR点云进行滤波,在此基础上利用点云回波特性和点云法向量检测并删除非地面点中特征明显的植被点和建筑物墙面点,然后利用连通成分分析法对非地面点聚类得到初始建筑点,最后结合DTM并利用建筑物面积和高度信息分离得到建筑物屋顶点云.试验结果表明,本方法能有效地从机载点云数据中快速提取建筑屋顶点云,有效率可达85%以上. 相似文献
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《科技通报》2016,(5)
在地质滑坡灾害的防治领域,需要对山层进行层面重构,分析山体的层面断层效应和数学模型,重构出地质层位曲面,为地质灾害的防治提供理论基础。传统方法对地质山层的断层重构采用离散点Delaunay的三角网快速生成算法,在三角网扩展时对离散点断面约束曲面的重构效果不好。提出一种基于地质逆断层区域分支约束的地质山层断层面重构方法,进行断层效应分析。分析了地质滑坡灾害的山体地质层的构造和断层层面重构方法,进行山体断层的内部结构参数体系分析和物理构造,然后采用层位插值和矢量裁剪方法进行地质山体滑坡的山层断层三维建模,采用地质逆断层区域分支约束方法,得到断层区域层位面的位置和空间预测值。仿真结果表明,采用方法能有效准确反映地质层的边界信息,断层复杂地质构造得到准确的拟合,通过精确地拟合出断层面的种子点和空间发展趋势,能有效实现对地质滑坡灾害的预测防治。 相似文献
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传统的滤波方法不能满足测量公路平整度的精度要求。为此,提出一种新的用于公路平整度测量的滤波算法。利用伪距和多普勒频移建立乘性噪声测量模型,利用二阶马尔卡夫对模型进行变换,在运用卡尔曼算法进行滤波,消除测量中的伪距和多普勒频移干扰误差,完成优化测量。结果表明,利用该算法能够有效消除GPS信道中的乘性噪声,实现了对公路平整度的精确测量。 相似文献
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插值算法被大量地运用在飞行器设计的过程中,不同的差值算法对结果精度会产生很大的影响。本文给出了几种插值算法的定义及求解过程,并使用MATLAB实现了算法,进行了算例比较。结果表明,在非线性情况下,三次样条插值法的精度较高,与原始数据更加吻合。 相似文献
10.
《中国科技信息》2020,(14)
本文根据三维图像和决策树模型设计基于颜色与三维形状的水果识别算法,并评价该算法的识别准确率。根据所采集到的125张三维图像信息,首先将RGB数据进行灰度处理和高斯滤波处理,而后按照Canny算法进行边缘检测,从而提取目标物体的颜色特征,将目标的RGB数据与深度数据转化为点云模型,再将点云模型进行点云滤波处理、点云分割操作,提取出目标物体的点云模型,最后根据拟合点云模型和拟合球体的方差从而提取出目标物体的三维形状特征。通过CART算法构建基于颜色与三维形状的水果识别模型,使用识别率评价模型效能,本文算法的识别准确率高达94%。结果表明,该算法可以极大提升水果识别效率,缩短水果分类周期,提高水果分类准确率,减少劳动力的消耗。 相似文献
11.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
12.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
13.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
14.
《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
15.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
16.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
17.
Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献
18.
Milton Mueller 《The Information Society》2001,17(3):151-163
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP. 相似文献
19.
Prof. Raymond C.K. Chen a neuropsychologist with the CAS Institute of Psychology has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology. 相似文献
20.
《中国科学院院刊(英文版)》2014,(3)
<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence 相似文献