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81.
一种弧焊机器人实时激光扫描视觉系统 总被引:2,自引:0,他引:2
研制了一种小型高精度弧焊机器人实时激光扫描视觉系统,对其各项性能进行了测试,并进行了抗电弧光干扰试验,结果表明,此系统精度高,抗干扰能力强,检测范围宽,能广泛地应秀于机器人和自动化焊接中。 相似文献
82.
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84.
Jung‐Hyun Cho Michael Bass Hans P. Jenssen 《Journal of the Society for Information Display》2007,15(12):1029-1036
Abstract— Several rare‐earth‐doped fluoride crystals that are excited to emit visible light by sequential two‐photon absorption have been investigated as display‐medium candidates for static volumetric three‐dimensional displays. Dispersion of powders of these materials in a refractive‐index‐matched polymer is reported because such a medium may result in a scalable display. The scattering problem in such a medium is greatly reduced by index‐matching the polymer to the crystalline particles. An index‐matching condition that optimizes the performance is identified. 相似文献
85.
86.
H.L. Zou 《Computer aided design》2007,39(11):1025-1036
3D models reconstructed from 2D sketches are inaccurate because of the inherent inaccuracies in the input and the reconstruction method. It is therefore necessary to “beautify” them before use in CAD systems. We present a method that detects geometric constraints, such as parallel and orthogonal faces, present in the reconstructed model and then selects a subset that constrains the object sufficiently and consistently. The subset selection algorithm first prioritizes the constraints depending on their type and then uses a novel method, based on quasi-Newton optimization, to detect and eliminate redundant and inconsistent constraints. The remaining constraints then define the dimensions of the model fully and consistently. Results from our implementation show that the method can beautify and dimension recovered 3D models correctly at acceptable speed. 相似文献
87.
Chen-Tsung Kuo Author Vitae 《Pattern recognition》2007,40(2):742-755
Three dimensional models play an important role in many applications; the problem is how to select the appropriate models from a 3D database rapidly and accurately. In recent years, a variety of shape representations, statistical methods, and geometric algorithms have been proposed for matching 3D shapes or models. In this paper, we propose a 3D shape representation scheme based on a combination of principal plane analysis and dynamic programming. The proposed 3D shape representation scheme consists of three steps. First, a 3D model is transformed into a 2D image by projecting the vertices of the model onto its principal plane. Second, the convex hall of the 2D shape of the model is further segmented into multiple disjoint triangles using dynamic programming. Finally, for each triangle, a projection score histogram and moments are extracted as the feature vectors for similarity searching. Experimental results showed the robustness of the proposed scheme, which resists translation, rotation, scaling, noise, and destructive attacks. The proposed 3D model retrieval method performs fairly well in retrieving models having similar characteristics from a database of 3D models. 相似文献
88.
这里根据轮盘、板类等常用机械零件一般含有规则和非规则分布的相同结构的特点,总结出应用功能强大的Solid Works软件进行该类零件三雏设计的多种实用方法,给出了含有非规则分布的相同结构零件的快速设计方法,并分析了各种方法的应用场合。 相似文献
89.
I.C. Demetriou 《Computer Physics Communications》1997,100(3):297-310
A Fortan subroutine calculates the least squares approximation to n data values containing random errors subject to non-negative second divided differences (convexity). The method employs a dual active set quadratic programming technique that allows several concavities of an iterate to be corrected simultaneously, which is a distinctive feature of this calculation. A B-spline representation of the iterates reduces each active set calculation to an unconstrained minimization with fewer variables that requires only O(n) computer operations. Details in these techniques including the data structure that establishes the implementation of the method are specified. Numerical testing on a variety of data sets indicates that the subroutine is particularly efficient, terminating after a small number of active set changes, the subroutine being suitable for large numbers of data. A numerical example and its output is provided to help the use of the software. 相似文献
90.
本文对[5]的4位人工神经网络A/D变换器进行了研究.指出按其方法推广实现多位A/D时存在突触电阻大小以至无法实现且抗干扰能力也不好的问题并给出了解决办法.同时对如何改善神经元转移特性的硬限幅曲线作了简单讨论. 相似文献