排序方式: 共有13条查询结果,搜索用时 15 毫秒
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Shinichi Takita Kazufumi Kaneda Toshio Akinobu Haruhiko Iriyama Eihachiro Nakamae Tomoyuki Nishita 《The Visual computer》1991,7(5-6):259-268
A simple rendering method for penumbrae caused by sunlight is proposed to create more realistic outdoor scenery. Only four points are used to define the penumbra area cast by a contour edge so that little storage is needed for penumbra areas. Complex penumbrae caused by such objects as curtains can be rendered. Calculation of illumination in the shadows cast by natural objects, such as trees, mapped on a transparent virtual plane is available. In order to show the usefulness of the proposed method, some computer-generated images with penumbrae are compared with those without penumbrae. 相似文献
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A new technique is developed for displaying disjoint convex polyhedra. The method has the following properties: It is output-sensitive, displays the objects in scanline mode, and it is naturally robust. There is no complex data structure uniting the different polyhedra, so dynamic insertions and deletions are simple. Its robustnes is based on a novel method of comparing depths by representative "axes" of objects instead of surfaces. The method is based on two extensions of the "critical-points" method for polygon scan conversion: One extension allows the efficient display of planar graphs in scanline mode, and another extension is into the third dimension. Test runs indicate that it compares extremely favorably with other methods that operate in scanline mode, as well as with standard software and hardware techniques of medium-level workstations. 相似文献
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Direct display algorithms display a CSG model without first converting the model into a boundary representation. Three such algorithms are described. All three are based on the scanline display algorithm, and are able to handle both polygonal and quadratic faces.The first algorithm is based on Atherton's recursive subdivision scanline algorithm, the second is a combination of a scanline and a ray casting algorithm, and the third is a scanline version of the Trickle algorithm. A multiprocessor system in which these algorithms can be incorporated is also described.The performances of the algorithms are compared. It turns out that the algorithms efficiently display CSG models on general-purpose architectures. A comparison is also made between the performances for polygon-approximated models and exact models for objects bounded by quadratic faces, such as spherical, cylindrical and conical faces, to get an indication of how many polygons can at most be used to approximate quadratic faces and still have better performance. 相似文献
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在三维节理岩体模型 (其节理长度尺寸的分布是已知的 )的基础上 ,本文利用计算机模拟了节理迹长的线测量与面测量 ,并将二者测量的结果与真实的节理长度分布进行了对比 ,结果表明 ,线测量具有比面测量更高的精度 相似文献
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This paper deals with a novel stereo algorithm that can generate accurate dense disparity maps in real time.The algorithm employs an effective cross-based variable support aggregation strategy within a... 相似文献
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本文采用基于边的线扫描算法的图形逻辑操作,并以此为基础设计了一个层次化的电路提取器(HCE),单元重复利用率越高,层次化的电路提取器HCE比平面化的电路提取器的速度越快,并且,本提取器HCE能够处理非曼哈顿图形,提取器HCE系统是在HP9000/834图形工作站上开发完成的,该系统采用了已成为工业标准的软件开发环境,即UNIX操作系统,X窗口,C语言和EtherNet网络,便于系统移植、维护和再开 相似文献
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A geometry-based investigation of the tool path generation for zigzag pocket machining 总被引:8,自引:0,他引:8
Martin Held 《The Visual computer》1991,7(5-6):296-308
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Accurate real-time stereo correspondence using intra- and inter-scanline optimization 总被引:1,自引:1,他引:0
This paper deals with a novel stereo algorithm that can generate accurate dense disparity maps in real time. The algorithm employs an effective cross-based variable support aggregation strategy within a scanline optimization framework. Rather than matching intensities directly, the use of adaptive support aggregation allows for precisely handling the weak textured regions as well as depth discontinuities. To improve the disparity results with global reasoning, we reformulate the energy function on a tree structure over the whole 2D image area, as opposed to dynamic programming of individual scanlines. By applying both intra- and inter-scanline optimizations, the algorithm reduces the typical ’streaking’ artifact while maintaining high computational efficiency. The experimental results are evaluated on the Middlebury stereo dataset, showing that our approach is among the best for all real-time approaches. We implement the algorithm on a commodity graphics card with CUDA architecture, running at about 35 fames/s for a typical stereo pair with a resolution of 384×288 and 16 disparity levels. 相似文献