基于曲线端点插值平面起控的桥梁航拍图像识别

在计算机辅助三维桥梁重构和桥梁目标识别中,桥梁图像曲线曲面的形状平滑处理是关键。传统方法采用Bézier曲线曲面的自然生成方法,算法没有提升桥梁曲面多项式生成的次数,所以计算复杂度较大,三维平滑效果不佳。提出一种基于曲线端点插值平面起控的三维桥梁航拍图像HC-Bézi-er生成方法实现,对航拍图像识别。定义具有凸包性、对称性等基本性质的新曲线,对三维桥梁平面曲线端点进行控制边重合插值,组合曲线的各曲线段,构造了含积分递推多项式的平面起控基函数,实现三维桥梁图像曲线曲面的精确平滑处理和三维重构模拟。仿真实验表明,采用该算法进行三维桥梁图像模拟,桥梁曲线和曲面可以由不同数量的轮廓点控制,具有形状可调性,实现高阶的光滑拼接,信息分析准确,信息含有量饱满,实现准确三维重构,基于重构图像对航拍桥梁图像检测点的准确识别率较传统方法提高明显。     

针对航空随机场景约束的虚拟建模方法研究

提出一种专门针对航空随机场景的建模方法在采集得到航空随机二维图像后,对随机图像采集角点图像,特征点转换到HSV空间内,去除航空随机场景中的干扰,对比图像中某点的像素值和其在阴影区域中的像素值,若某点的阴影像素值包含的色度值、亮度值以及饱和度满足相应的阀值,在进行双目立体视觉的三维重建,保证视觉计算的真实性。后期的计算机仿真实验证明,改进算法能够有效的消除运动状态下的视觉阴影,提高航空随机场景中虚拟模拟飞行环境的真实度     

基于视频像素灰度值时延估计的暴恐人员圆阵定位

从视频像素灰度序列中提取特定人员的状态特征,采用平面阵对特征信息进行融合处理是实现计算机视觉下特定人员定位的重要步骤。传统的人员视觉定位方法采用视频步进跟踪学习方法,在随机状态分布下的复杂环境人员进行准确定位效果不佳,提出一种基于平面圆阵定位算法的特定人员计算机视觉定位方法,提取监控视频的图像,进行视频图像的背景建模,得到高斯差分尺度空间中的背景像素灰度值,实现对特定人员的表情识别的动作判别,以此为数据基础设计平面圆阵人员定位系统,实现对暴恐等特定人员的准确锁定和跟踪识别。仿真实验表明,采用该算法准确实现1500 m远距离暴恐人员特征识别与定位,误差较小,分辨率和准确性较高。     

基于特征相关的图像配准与拼接算法研究

图像拼接技术现在应用的范围已经愈加广泛,无论在计算机视觉,三维重建,医学图像处理,全景建设等领域都得到了广泛应用。作为图像处理领域的一门科学,已经受到越来越多的重视。本文对图像拼接的基本原理进行说明介绍,同时介绍一些基本的拼接算法,主要是基于特征点的研究。并且对图像拼接未来的发展进行一个展望。     

基于光线滤波平滑处理的三维成像技术

三维虚拟成像通过对场景的动态模拟和优质的图像处理,从而给人强烈的视觉上的冲击。传统的三维成像技术采用纹理映射技术,当纹理特征受到不均匀光线干扰时,成像效果不好。提出一种基于光线滤波平滑处理的三维成像技术,结合静态视点图像的运动方程,计算视点控制视觉切换偏角,按内插点的分布范围,可以将内插分为整体内插、分块内插和逐点内插,提高三维成像的立体型,实现了三维成像的特征提取预处理。将一个归一化的灰度图像通过矩估计测得二值图中的图像面积,三维模型通过多层网格面来表示,使得三维实体模型成为一个连续的整体,生成多层网络面,通过光线滤波平滑处理,当纹理特征受到不均匀光线干扰时,仍然保持较好的成像效果。仿真结果表明,算法能通过图像分割,实现图像特征提取,并实现光线滤波平滑处理,进行三维成像,成像误差较小,三维成像的测量值逼近理论值,性能优越。     

一种加权局部熵羽化的图像拼接模型

图像拼接技术能多幅背景相似的图像合成为一张全景图像,也可以补充某些图像缺失的部分,但是目前常用的拼接算法还存在准确性不高、鲁棒性不强的缺陷,为此本文提出了一种加权局部熵羽化的图像拼接模型。首先对图像的局部熵进行羽化,然后采用一元线性回归的方法对邻域像素的灰度图像进行相似度的优化,最后对图像的局部熵进行加权,以突出图像中领域像素之间的块相似度,降低羽化的痕迹。模型的对比仿真结果表明,本文提出的算法相比较SIFT算法,对于动态图像的拼接具有更高的准确性,并且抗噪性能更加,具有较好的鲁棒性。     

基于差异维数约束自然语义模型的图形描述算法

提出了一种基于差异约束自然语义模型的图形描述算法,建立了自然图像特征的差异相似模型,并用维数约简对图像中转化的歧义特征进行分类,实现了计算机图形的视觉特征到语义描述的转换.消除了图像转化中的歧义.实验结果证明,该方法在图像的特征理解和基于自然语义的图像特征描述中,有助于缩小图像特征的数学描述和人类理解之间的语义歧义,取得了良好的效果.     

基于虚拟双目视觉的玉米叶片三维重建方法

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。     

基于图像纹理特征采用网格细分方法生成三维地形

三维地形可视化是虚拟环境漫游研究的一个重要问题,通常采用高精度网格简化算法来保留地形的细部特征,形成多分辨率网格以提高显示效率,但在简化过程中需要额外考虑消除裂缝、连接和误差度量等计算。文章采用了一种逆向方法,即基于图像纹理特征网格细分方法生成三维地形;将含有地形高程纹理特征的图像映射到一个规则初始网格模型中,根据三角边与它的纹理特征曲线相交情况来细分网格,从而也实现了多分辨率三维地形模型。该方法的主要特点是生成结果除了能够反映虚拟地形的细节特征外,无需考虑消除裂缝和连接计算过程。     

基于单帧视频序列多目标约束的三维重建技术

在视频图像序列中,假设目标的数量较多,会形成较大的干扰,利用传统算法对目标进行三维重建,会出现目标像素混合、特征丢失的问题,造成传统算法不能得到很好的约束效果,三维重建真实性较差,从而导致多目标三维重建失真.为了解决这一问题,本文提出了一种基于多目标约束立体视觉算法的抗干扰三维物体重建方法.提取视频序列不同图像中的目标特征点,加入形变约束分析方法,准确计算建模物体的形变,抵抗特征丢失带来的干扰,再利用立体视觉技术进行多目标三维重建.实验结果表明,这种算法能够有效提高多目标三维重建的真实性,取得了令人满意的效果.     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

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.     

Cooler temperatures inductive to locust outbreaks

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.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

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.     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

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.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

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.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

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.     

Prevalence of soft neurological signs in Chinese people

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.     

Monoculture Rubber Plantations Have Negative Ef ects on Controlling Splash Erosion

<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     

Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels

<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese     

More than Skin Deep – Understand Skin Biology by Means of Dermatogenomics

<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages.