Overlap Operations and Raster Graphics

This paper outlines the development of a volume and surfaces modelling system for use with raster graphic displays. The ideas are presented in a historical framework to make the reasoning behind the design decisions clear and to indicate the main influences which have guided the work. There are two outcomes of importance: a language form for defining volumes and surfaces; and hardware to convert this representation directly into a display. The hardware provides hidden-line or hidden-area removal as a display primitive which, in an appropriate implementation, can be fast enough to support a range of real-time display applications. Linked to this hidden-line, hidden-area removal facility is an ability to provide interference tests for objects that are being moved around in a scene. Again there appears to be a hierarchy of applications ranging in complexity from interactive volume editing to robot control and vision systems. The new facilities complement existing point and line based display operations, on which most current displays' hardware is based. A good case is emerging for integrating the two approaches into a single hardware implementation for CAD workstations and for simulator display systems.     

Memory Design for Raster Graphics Displays

This tutorial examines the origin and nature of the problem of contention for memory cycles?a problem that impacts the image update performance of every raster graphics system.     

PERQ and Advanced Raster Graphics Workstations

A National Network of Inexpensive, High-Powered, Single-User Computers with Good Interactive Capabilities Is Being Launched in the UK.     

矢量图形在非自交多边形中的裁剪算法

计算机图形学中裁剪算法的效率会直接影响到图形计算、处理、显示的速度和用户体验.本文在Java环境下,围绕降低循环中冗余计算、重用对象、多线程控制等方面,对传统的矢量图裁剪算法进行改进.改进后的算法在执行效率和内存消耗上均优于传统的矢量图裁剪算法.该算法的应用可以有效的提高工程图形的生成效率.     

Increasing Capabilities in Interactive Computer Graphics Terminals

The earliest interactive computer graphics terminals were closely coupled to their central computers and placed heavy loads upon them for resource allocation. Two marked trends in the evolution of terminals have been a reduction of central computer load and exploitation of the increasing performance/cost ratio for terminal equipment. The trends have led to graphics terminals that operate on a stand-alone basis. The history of these trends is traced and particularly illustrated by the cases of the fully interactive, refreshed CRT GRAPHIC 21 and the simply interactive, storage CRT GRAPHIC 101 terminals.     

A General-Purpose Multi-Microprocessor Raster Graphics Display System with Anti-Aliasing

The raster graphics display system described represents a general purpose mini-computer, specially for CAD applications. The system is based on a hierarchical asynchronous multiple microprocessor system. In practice this mini-computer is extendable up to 15–20 workstations. On the workstations, different graphical and non-graphical devices can be connected. The most interesting workstation is a raster graphics display device which was developed specially for the computer system described. This raster graphics display device contains a processor for the application program, two dedicated processors and two separate identical frame buffers, each of them containing one whole set of image data. Applying algorithms for anti-aliasing, virtual pixel dislocation (intensity dislocation) and multi-pixel-overlappings with hidden line (surface) elimination the image readability and quality can be increased considerably. In particular the paper deals with an anti-aliasing algorithm with a real-time hardware realization.     

并行栅格扫描填充路径及其规划算法

深入分析快速成形制件翘曲变形的原因后,提出一种全新的扫描填充路径--并行栅格路径及其规划算法.按照这种路径能够近似、并行地完成整个待成形二维平面区域的扫描填充过程,在减小XY向温度梯度的同时,均匀化不同位置材料成形后的冷却收缩约束力,使得不同位置材料的冷却收缩趋于同步和均匀,减小了制件的整体翘曲变形量.实验表明,该算法能够在与其他类型路径的规划算法大致相当的时间和空间复杂度下,获得扫描填充性能更加优越的路径.     

Some Issues in Designing User Interfaces to 3D Raster Graphics

Now that raster graphics has become a common tool in CAD/CAM systems, animation and many other applications, the need has arisen for user interfaces to graphics packages for these new applications. On the basis of a typology of the users, an analysis is presented of some of the choices which have to be made in developing these interfaces.     

一种快速的复杂多边形匹配算法

提出了一种能够快速进行复杂形状多边形匹配的算法，该算法基于正切空间表示，先对复杂多边形进行离散曲线演化，再将得到的简化多边形分为一系列最大凸/凹弧线，并选择每段最大凸弧线的起点作为匹配的起始点进行匹配。实验结果证明该算法不但能够对复杂多边形快速而精确的匹配，而且具有不受噪声影响的优点。     

地理栅格数据的并行访问方法研究

在海量地理栅格数据处理中,数据I/O性能是影响处理算法程序整体性能的关键。目前针对地理栅格数据 I/O优化问题的研究成果还很有限,通过对并行程序中的数据I/O模式进行深入分析,结合栅格数据逻辑模型和物理 模型的特点,提出了面向地理栅格数据的并行I/O框架;基于消息传递模型,实现了4种并行访问方法。实验证明,并 行访问方法优于传统的串行访问方法和分时多进程访问方法。该研究成果可以提高并行栅格处理程序的I/()访问效 率,进而提高其整体并行性能。     

基于复数小波域的图形水印方法

提出了一种基于复数小波域的2维矢量图形的水印算法，用于2维矢量图形的版权保护。该算法利用了Dual Tree复数小波变换的优点，将水印嵌人相对坐标线(relative coordinates line)的复数小波域中。经初步实验结果验证，该算法对于通常的图形几何变换，如平移、旋转、缩放以及局部修改攻击，均有令人满意的鲁棒性。     

基于Matlab的图形轮廓提取及填充

提取图形的形状特征是当前图像处理领域的重要研究内容,而图形的边缘轮廓又能很好地反映形状的信息,因此本文阐述了如何利用matlab较好的提取图形的轮廓,以及将简单轮廓图形填充起来作为形状图形进行研究的算法及代码实现。     

基于MFC的DirectDraw高速图形绘制方法与应用

在工业控制环境下采用GDI内存作图方式可以加速图形绘制,但对复杂图形的高速绘制效果并不理想.提出以MFC编程来实现基于DirectDraw实时图形绘制方法,能产生快速、平稳的复杂图形,并且通过一个复杂图形绘制的实例,详细讨论了的步骤.     

用fBm法生成山脉地形的真实感图形的方法

介绍了fBm方法的基本原理和特点,给出了在三维空间中用中点偏移法生成山脉地形数据模型的算法,提出了一种基于OpenGL山脉地形真实感显示方法,并通过实例验证其科学性和可行性。     

在Authorware中实现建筑图形放大的三种方法

介绍了在Authorware实现图形放大的三种方法。阐述了每种方法的设计和实现方法，并将三种方法作了比较。     

以工程意识教育为导向的工程图学能力培养方法探析

摘 要：本科阶段加强学生工程意识培养重要而紧迫,分析了现代工程意识和能力培养的主要内容,以工程图学课程为切入点探究了课程教学内容与工程意识的密切联系,基于工程意识培养的可行方案,针对不同教学环节的培养方法进行创新设计,并配套设计了工程意识实验环节,使得教学手段更为立体、方法更为多样,为培养理论基础扎实的现代工程创新人才提供了有效途径。     

基于栅格的任意复杂区域自动填充算法

基于栅格与等间距平行线原理,设计出一种适用于任意复杂区域完全自动化填充 算法。首先,将整个填充区域栅格化。其次,绘制一组等间距平行线,计算每条平行线经过多 边形区域内栅格的行列序号值。最后,根据计算出栅格的行列序号值,采用自主循环方法对每 个栅格单元填充,最终实现整个区域的自动化填充。通过自主设计的应用程序验证多组数据表 示该算法能快速自动填充,对实验中出现的技术难点做了详细分析。