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RANGE ACQUISITION IN BINOCULAR 3-D COMPUTER VISION USING EDGE-BASED HIERARCHICAL MATCHING
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作者 李允明 金声 《Journal of China Textile University(English Edition)》 EI CAS 1990年第1期1-6,共6页
This paper deals with a binocular 3-D computer vision system based on the hierarchicalmatching of edge features, Frei and Chen operator is used to extract the edge. The averagegradients of an image obtained by two iso... This paper deals with a binocular 3-D computer vision system based on the hierarchicalmatching of edge features, Frei and Chen operator is used to extract the edge. The averagegradients of an image obtained by two isotropic operators are non-equal quantized andthresholded in an angle, Edge features are extracted after passing a preemphasis transferfunction which can equalize, the noise affection. Binary edge images are decomposed into apyramid structure which is stored and searched using llliffe’s location method. Corre-sponding points are used to determine the range data using triangulation based on an improvedTrivedi’s formula. In calibration the authors set the optical axes of the two cameras parallelto simplify the calculation, A 3 rd order Householder transform is used to solve the compati-ble coupled equations. 展开更多
关键词 BINOCULAR VISION hierarchy pyramid 3-d computer VISION hierarchical registration RANGE ACQUISITION
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Efficient Hierarchical Algorithm for Mixed Mode Placement in Three Dimensional Integrated Circuit Chip Designs
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作者 闫海霞 周强 +1 位作者 洪先龙 李卓远 《Tsinghua Science and Technology》 SCIE EI CAS 2009年第2期161-169,共9页
Hierarchical art was used to solve the mixed mode placement for three dimensional (3-D) integrated circuit design. The 3-D placement flow stream includes hierarchical clustering, hierarchical 3-D floorplanning, vert... Hierarchical art was used to solve the mixed mode placement for three dimensional (3-D) integrated circuit design. The 3-D placement flow stream includes hierarchical clustering, hierarchical 3-D floorplanning, vertical via mapping, and recursive two dimensional (2-D) global/detailed placement phases. With state-of-the-art clustering and de-clustering phases, the design complexity was reduced to enhance the placement algorithm efficiency and capacity. The 3-D floorplanning phase solved the layer assignment problem and controlled the number of vertical vias. The vertical via mapping transformed the 3-D placement problem to a set of 2-D placement sub-problems, which not only simplifies the original 3-D placement problem, but also generates the vertical via assignment solution for the routing phase. The design optimizes both the wire length and the thermal load in the floorplan and placement phases to improve the performance and reliability of 3-D integrate circuits. Experiments on IBM benchmarks show that the total wire length is reduced from 15% to 35% relative to 2-D placement with two to four stacked layers, with the number of vertical vias minimized to satisfy a pre-defined upper bound constraint. The maximum temperature is reduced by 16% with two-stage optimization on four stacked layers. 展开更多
关键词 hierarchical three dimensional 3-d mixed mode placement vertical via integrate circuit
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节理岩体的三维阶谱复合单元法初步研究 被引量:3
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作者 彭成佳 陈胜宏 《岩土力学》 EI CAS CSCD 北大核心 2007年第4期817-822,共6页
阐述了节理岩体复合单元法基本原理,引入了阶谱有限单元法中的虚节点和广义节点概念,提出了覆盖虚棱(面)和广义棱(面)的概念,并进一步将虚节点和广义节点分类。在此基础上构造了节理岩体的三维复合单元不同阶次时的位移函数并推导了对... 阐述了节理岩体复合单元法基本原理,引入了阶谱有限单元法中的虚节点和广义节点概念,提出了覆盖虚棱(面)和广义棱(面)的概念,并进一步将虚节点和广义节点分类。在此基础上构造了节理岩体的三维复合单元不同阶次时的位移函数并推导了对应的刚度矩阵。算例表明此法是合理有效的。提出的概念有助于复合单元法和传统有限单元法二者升阶谱的理解与统一实现,并为实现节理岩体三维复合单元法的P型自适应奠定了基础。 展开更多
关键词 节理岩体 阶谱单元 覆盖 广义节点 三维阶谱复合单元法
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