一种支持多线宽直线反走样算法

直线绘制中出现的锯齿现象称为走样,消除走样的方法称为反走样。文中通过对直线走样产生的原因进行理论上的分析,总结了现有的反走样技术。通过对经典的DDA直线绘制算法和Wu直线反走样绘制算法的研究,在二者结合的基础上,给出了一种任意宽度和复杂背景色下的直线反走样快速绘制算法：对于直线f（x）=mx＋b,0≤m≤1,x轴上每移动一个像素单位,根据直线所需绘制的宽度,在y轴上进行跨度像素着色,填充的色深值取决于该像素到对应直线边缘线的距离、原有背景色深和当前直线绘制色深。对算法进行了去浮点优化,给出了复杂度分析和实验结果,实践证明,该算法有很好的执行效率和反走样效果。     

一种快速的多线宽直线反走样算法

对于直线绘制中出现的锯齿现象称为走样,消除走样的方法称为反走样,通过对直线走样产生的原因进行理论上的分析,了现有的反走样技术。通过对经典的DDA直线绘制算法和Wu直线反走样绘制算法的研究,在二者结合的基础上,给出了一种任意宽度和复杂背景色下的直线反走样快速绘制算法：对于直线f（x）=mx+b,0≤m≤1,x轴上每移动一个像素单位,根据直线所需绘制的宽度,在y轴上进行跨度像素着色,填充的色深取决于该像素到对应直线边缘线的距离、原有背景色和当前直线绘制色。对算法进行了去浮点优化,给出了复杂度分析和实验结果。实践证明,该算法有很好的执行效率和反走样效果。     

基于点到直线距离的直线扫描转换算法

直线扫描转换算法是计算机图形学和计算机辅助设计等领域最基本、最重要的算法之一,直线反走样算法也是光栅化图形算法中的重要内容。文中提出了一种基于点到直线距离的直线扫描转换算法,给出了算法的推导过程及代码表示,并介绍了算法在直线反走样中的具体应用。该算法基于增量技术,采用点到直线的距离作为判别式,在扫描转换过程中,可方便地根据点到直线的距离,采用加权区域采样的方法进行直线的反走样,提高了反走样的效率;具有只使用整型变量、不涉及乘除运算的特点,适合硬件实现。     

反走样直线的灰度循环生成算法

灰度转换是整数反走样直线和曲线绘制算法中较为耗时的操作.为了提高反走样直线的绘制效率,提出了一种直接利用灰度循环控制生成反走样直线的纯整数算法.该算法采用两点反走样模式,根据对灰度值的分解、每次步进时的像素及其灰度值直接利用灰度增量控制产生,从而避免了候选点与真实直线之间的距离计算,以及由距离到灰度的转换.分析表明,该算法每次步进仅需要4～5次整数基本运算,其效率较现有整数反走样直线生成算法有大幅度提高,且具有与基本直线生成算法相似的简单性.     

基于嵌入式图形系统的改进Bresenham反走样算法

基于Bresenham算法，依据去浮点数计算原理，结合矩形滤波反走样技术，提出了一种快速的反走样直线的优化算法．并在配备ARM7微控制器LPC2290的Magic ARM2200仪器上得以实现。该算法明显加快了反走样直线的生成速度并在低分辨率的显示环境中获得非常好的效果。     

嵌入半球形滤波快速反走样画线方法

直线生成算法的优劣对计算机绘图及应用至关重要。Bresenham算法是最有效的直线生成算法,利用直线的两侧对称性可以进一步加快生成速度。但由于受到光栅扫描显示器的限制,用离散像素绘制的直线存在走样问题,实际应用中经常需要进行反走样处理。基于Bresenham算法,并依据直线的对称生成原理,与Hemisphere-filter反走样技术相结合,提出了一种新的快速反走样直线的生成算法。     

一种支持多线宽直线反走样算法

从理论上说明了反走样现象的产生和解决办法,结合经典的DDA画线算法与Wu反走样算法,给出了一种任意线宽和复杂背景色下的直线反走样快速绘制算法:在x(y)轴上以一个像素单位的步长进行移动,而在直线的y(x)方向上根据直线的宽度,进行跨度像素填充,填充的色深值依赖于该像素到直线中心线的距离、原有背景色和当前直线绘制色。最后,对算法进行去浮点优化,给出了复杂度分析、实验结果及应用情况。     

圆的像素级生成及反走样算法

介绍了圆的逐点生成算法的研究现状,指出被忽视了的Kuzmin逐点生成圆弧算法具有最小计算量,指出并纠正其存在的严重错误;然后,提出了一种双点生成圆弧算法．该算法只用整数运算来选择距离圆弧最近的像素点,比较结果表明,该算法比现有其他算法具有更快的执行速度;最后,在文中算法的基础上提出了一个生成反走样圆弧的算法且没有增加算法的计算量．该算法与惟一可比的双点生成反走样圆弧的Wu—Rokne算法进行比较的结果表明,该算法比后者多产生了4个中间灰度级,并且所生成的反走样圆弧的最大光强误差比后者减少了40％．文中算法便于硬件实现．     

基于FPGA的直线反走样算法研究

反走样是计算机图形学的基本问题。为了提高直线反走样的效率,针对FPGA硬件实现的特点,结合经典的Wu反走样算法,提出一种新的直线反走样算法。该算法根据像素点中心到理想直线的距离来计算灰度值,在生成直线时预测直线相邻像素点之间的灰度值变化,并建立递推公式,使用整数移位、加法和比较来完成直线反走样,计算简单,便于硬件实现。经计算机和FPGA分别实现验证,新算法的反走样效果较好,运算速度快于Wu反走样算法并能通过FPGA进一步提高速度。     

基于FPGA的直线反走样算法研究

反走样是计算机图形学的基本问题.为了提高直线反走样的效率,针对FPGA硬件实现的特点,结合经典的Wu反走样算法,提出一种新的直线反走样算法.该算法根据像素点中心到理想直线的距离来计算灰度值,在生成直线时预测直线相邻像素点之间的灰度值变化,并建立递推公式,使用整数移位,加法和比较来完成直线反走样,计箅简单,便于硬件实现.经计算机和FPGA分别实现验证,新算法的反走样效果较好,运算速度快于Wu反走样算法并能通过FPGA进一步提高速度.     

Only connect: teaching, technology and telesis

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.     

European Community policy and the market

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.     

一种自适应子融合集成多分类器方法

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。     

Avoiding semantic and temporal gaps in developing software intensive systems

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.     

Designing economic np control charts: A programmed simulation approach

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.     

The development of robot art

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     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。