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1.
为保持曲面浮雕的细节特征,改善浮雕与背景曲面的过渡效果,提出一种细节保持的曲面浮雕算法.首先采用Canny算子在梯度域定位内外轮廓,获得连续的梯度域;其次提出非线性函数,并用其压缩梯度幅值实现形状压缩;再通过双边滤波算子来保持和增强浮雕细节;最终通过求解积分方程重建曲面浮雕.该算法将背景曲面作为积分方程的优化条件,使浮雕在轮廓处向曲面光滑过渡;在重建过程中利用Fourier变换的微分性质在频域实现方程的精确求解,无需设置迭代收敛条件;通过调整参数可方便地控制浮雕整体变化范围、细节锐化程度以及浮雕与背景曲面的过渡效果.实验结果表明,文中算法参数的几何意义直观,所得曲面浮雕细节清晰,边界过渡自然. 相似文献
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参数曲面作为CAGD中形状数学描述的标准形式一直受到关注,而参数曲面的光滑拼接作为实现复杂客体几何造型的重要手段一直是该领域的一个热点和难点问题.以不同参数域的参数曲面为线索,对常用的矩形域和三角域参数曲面的GC1光滑拼接的条件进行了分析,同时对这些条件在实际应用中的一些问题进行了讨论,最后对曲面光滑拼接中一些令人关注问题进行了展望. 相似文献
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针对代数曲面拼接中存在直接通过符号计算方法得到的拼接曲面有时不能满足实际拼接需求的问题,提出2种对二次曲面的拼接曲面进行调整的方法:1)计算拼接曲面之前,在构造的方程中加入参数,然后利用结式能够对含有参数的代数方程进行消元的性质得到带有参数的过渡曲面,调整参数的值改变从一个曲面过渡到另一个曲面的速度使得曲面形状改变;2)在计算出结式后,通过增加补偿参数或函数使得曲面的形状改变.文中还从理论上分析并证明了这2种方法可以保持原来拼接曲面光滑连续性的阶数.实验结果表明,文中方法具有很强的通用性且易于实现. 相似文献
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严兰兰 《计算机工程与科学》2014,36(2):317-324
虽然三角域上的曲面造型方法能有效解决不规则产品的几何造型问题, 在实际工程中有着广泛的应用, 但由于其结构的特殊性和复杂性, 目前对三角域曲面的扩展研究并不多。为了丰富三角域曲面的理论, 针对如何增强三角域曲面形状表示的灵活性进行了专门的研究。首先构造了一组三角域上含一个参数的四次多项式基函数, 它是三角域上二次Bernstein基函数的扩展。然后用递推的方式定义了三角域上含一个参数的n+2次多项式基函数, 它是三角域上n次Bernstein基函数的扩展。基于新的n+2次多项式基函数, 定义了相应的n阶三角域曲面。分析了基函数和曲面的性质, 新曲面不仅具备三角域上Bernstein Bézier曲面的基本性质, 而且还可以在不改变控制顶点的情况下, 通过改变参数的值来自由调整曲面的形状。 相似文献
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针对很多几何造型是带有约束条件的曲面拼接问题,在线性连续同伦的基础上提出了利用非线性同伦连续计算拼接曲面以进行三维造型的方法。首先,根据得到的截面(切片)的位置及其曲线方程确定插值点并得到插值多项式;其次,将此插值多项式作为非线性连续同伦映射函数并分别代入主曲面和辅助曲面的多项式方程得到过渡曲面的方程;然后,仅将插值变元作为变元而主、辅助曲面方程的变元作为参数,利用Sylvester结式消去过渡方程中的变元得到关于主曲面的拼接方程即造型曲面。利用该方法能实现带有控制点的曲面造型以及多曲面约束的几何造型,而且它可以确定造型过程中的中间形状及中间形状的位置,从而更加具有实用性。 相似文献
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讨论了过渡曲面的生成问题,指出了半径过渡和PDE方法构造过渡面的局限性,提出了用基于物理的能量曲面造型方法构造过渡曲面的方法,特别是用于解决管状封闭非周期性曲面和其他曲面间的过渡问题。该文详细讨论了基于物理的能量曲面造型方法构造过渡曲面的原理及求解方法,并给出了飞行器的翼身过渡和三通过渡的实例。 相似文献
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可展Bézier参数曲面 总被引:8,自引:1,他引:8
给出B啨zier参数曲面可展的特征 这里的B啨zier参数曲面包括三角域上的B B参数曲面和矩形域上的张量积B啨zier参数曲面 特别地 ,给出了三角域上可展二次B B参数曲面的具体形式及其构造方法 ,以及三角域上可展三次B B参数曲面为切线面的一种特例 相似文献
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S. Shaw 《Journal of Computer Assisted Learning》1993,9(2):93-99
Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained. 相似文献
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European Community policy and the market 总被引:1,自引:0,他引:1
C. Lloyd 《Journal of Computer Assisted Learning》1993,9(2):86-91
Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven. 相似文献
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融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。 相似文献
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张涛 《计算机测量与控制》2015,23(1):86-89
为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值. 相似文献
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Wayne O’Brien Author Vitae 《Journal of Systems and Software》2008,81(11):1997-2013
Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them. 相似文献
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This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives. 相似文献
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潘丽 《自动化与仪器仪表》2014,(7):80-82
自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。 相似文献
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Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what
is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic
sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and
its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of
an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify
robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can
or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
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Jacob Palme 《Software》1979,9(9):741-747
The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users. 相似文献