共查询到20条相似文献,搜索用时 31 毫秒
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基于工程图三维重建中的预处理与信息提取技术研究 总被引:1,自引:0,他引:1
提出了基于边界表示B-rep方法的工程图三维重建中对于二维工程图纸进行预处理和信息提取的一系列实用算法,涉及到工程图读入、实体过滤、视图分离、视图坐标规格化以及视图数据处理等流程.不但可以快速准确地获得二维工程视图中完备的几何信息和拓扑信息,而且处理对象并不局限于标准的工程三视图,对于工程一视图、二视图同样可以处理.这些算法已经应用于一个CAD原型系统并取得了较好的效果,为后续的三维重建工作提供了良好的基础. 相似文献
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Semantic information is very important for understanding 2D engineering drawings. However, this kind of information is implicit so that it is hard to be extracted and understood by computers. In this paper, we aim to identify the semantic information of shafts from their 2D drawings, and then reconstruct the 3D models. The 2D representations of shafts are diverse. By analyzing the characteristics of 2D drawings of shafts, we find that there is always a view which represents the projected outline of the shaft, and each loop in this view corresponds to an elemental part. The conditional random fields (CRFs) model is a classification technique which can automatically integrate various features, rather than manually organizing of heuristic rules. We first use a CRFs model to identify elemental parts with semantic information. The 3D elemental parts are then constructed by a parameters template method. Compared with the existing 3D reconstruction methods, our approach can obtain both geometrical information and semantic information of each part of shafts from 2D drawings. Several examples are provided to demonstrate that our algorithm can accurately handle diverse 2D drawings of shafts. 相似文献
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基于工程图样的三维重建技术研究与实现 总被引:20,自引:3,他引:20
提出一种新颖的基于工程图样理解的三维形体重建方法,设计了完整的算法,并建立了一个原型系统。文中的研究成果在三个方面取得了较大的进展:1)将重建对象从一般图形拓展到含半剖视图、全剖视图和尺寸标注的工程图样,使三维重建的实用化成为可能;2)较好地利用了工程图样语义进行形体分析,实施图形预处理,降低了特征识别的难度;3)将特征识别与三维重建结合起来,使重建结果包含形体信息,为利用重建结果进行更高层次的工 相似文献
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基于工程图的三维重建研究 总被引:4,自引:0,他引:4
由二维工程图重建三维形体是一种快速的形体造型方法,已成为计算机图形学和人工智能领域的重要研究方向.立足于基于工程图的三维重建问题,分类总结了形体重建方法的研究成果,着重介绍了典型的重建算法.在比较了典型算法的适用范围的基础上,剖析了目前形体重建研究所面临的问题.最后,指出了基于工程图的三维重建算法进一步的研究方向. 相似文献
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商品化CAD软件中基于二维视图的三维重建模块的设计与实现 总被引:5,自引:0,他引:5
探索出一种符合工程技术人员思维方式的基于二维视图的三维重建方法,并在商品化软件Solid2000中作为一个模块实现.解决了三维重建中DWG文件的数据转换、视图分离及视图的BOX显示、特征生成、重建结果验证、曲线拟合等问题.该模块以交互和自动结合的方式进行,设计完整实用,充分利用了二维视图信息,提高了三维建模的速度. 相似文献
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Serial 3D model reconstruction for machining evolution of rotational parts by merging semantic and graphic process planning information 总被引:1,自引:0,他引:1
The manufacturing of a mechanical part is a dynamic evolution process from a raw workpiece to the final part, in which the generation of serial 3D models reflecting the changes on geometric shapes is especially critical to digital manufacturing. In this paper, an approach driven by the process planning course, the machining semantics and the machining geometry to reconstruct incrementally the serial 3D models for rotational part’s dynamic evolution is proposed. The two major techniques involved are: (1) extraction of machining semantics based on process planning language understanding; (2) 3D reconstruction from 2D procedure working drawings guided by machining semantics and visualization for the reconstructed series of 3D models. Compared with the conventional 3D reconstruction methods, this approach introduced the process planning course and relevant information to implement a dynamic, incremental and knowledge-based reconstruction which can greatly reduce the efforts in reconstruction and extend the collection of geometric shapes to be reconstructed. 相似文献
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Tong Lu Huafei Yang Ruoyu Yang Shijie Cai 《International Journal on Document Analysis and Recognition》2007,9(1):31-47
Recognition and integration of 2D architectural drawings provide a sound basis for automatically evaluating building designs,
simulating safety, estimating construction cost or planning construction sequences. To accomplish these targets, difficulties
come from (1) an architectural project is usually composed of a series of related drawings, (2) 3D information of structural
objects may be expressed in 2D drawings, annotations, tables, or the composites of above expressions, and (3) a large number
of disturbing graphical primitives in architectural drawings complicate the recognition processes. In this paper, we propose
new methods to recognize typical structural objects and architectural symbols. Then the recognized results on the same floor
and drawings of different floors will be integrated automatically for accurate 3D reconstruction. 相似文献
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本文主要研究扫描工程图二维重建中图素间拓扑关系的识别和表达,建立了“无向有权图”的图素拓扑关系表达模型,并给出了相应的算法和基于该模型的实验结果。该模型的建立是实现最终达到尺寸驱动的扫描工程图二维重建的基础。 相似文献
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An engine that automatically reconstructs a large variety of polyhedral, origami and wire-frame objects from single-view sketched drawings generated in a calligraphic interface is presented. The engine has two stages. An innovative optimisation-based line-drawing beautifier stage is introduced to convert rough sketches into tidied-up line drawings. Optimisation-based 3D reconstruction follows. Solutions are provided with which to overcome the problems associated with earlier approaches to optimisation-based 3D reconstruction. Suitable adjustments in the optimisation algorithms are proposed; simple and efficient tentative models are introduced, and current regularities are categorised in order to allow the objective function to be simplified. All three actions help to prevent local optima and improve the computational efficiency of optimisation-based 3D reconstruction. They all proved to be effective techniques to reduce the typical failure rate of optimisation approaches. A discussion of results that validate the engine is also provided. 相似文献
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在自发荧光断层成像(Bioluminescent tomography imaging,BLT)中,双模态融合(光学模态与结构模态)可充分利用结构模态提供的高精度3D几何结构,重建三维表面荧光光通量分布,进而实现小动物内部荧光光源定位.然而,与纯光学模态相比,双模态融合存在采集系统复杂、成本高、数据处理繁琐及存在电离辐射(如CT)等问题.因此,研究基于纯光学3D几何结构的自发荧光光源定位方法对BLT具有重要意义. 本文在搭建纯光学自发荧光断层系统(All-optical bioluminescence tomography system,AOBTS)的基础上,提出一种基于多角度光学投影表面重建的三维自发荧光光源定位方法. 本方法由基于多角度光学投影的3D表面重建、多角度荧光无缝融合、荧光光通量的量化校正以及自发荧光内部光源重建4部分组成. 通过真实小鼠内部植入荧光光源实验表明,与传统纯光学方法相比,本文提出方法不仅改进了3D表面重建方法,而且增加了多角度荧光无缝融合,可实现真实小鼠的三维自发荧光光源定位,初步实验证明具有小动物预临床实验潜力. 相似文献
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Geographic,Geometrical and Semantic Reconstruction of Urban Scene from High Resolution Oblique Aerial Images
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Xiaofeng Sun Shuhan Shen Hainan Cui Lihua Hu Zhanyi Hu 《IEEE/CAA Journal of Automatica Sinica》2019,6(1):118-130
An effective approach is proposed for 3D urban scene reconstruction in the form of point cloud with semantic labeling. Starting from high resolution oblique aerial images, our approach proceeds through three main stages:geographic reconstruction, geometrical reconstruction and semantic reconstruction. The absolute position and orientation of all the cameras relative to the real world are recovered in the geographic reconstruction stage. Then, in the geometrical reconstruction stage, an improved multi-view stereo matching method is employed to produce 3D dense points with color and normal information by taking into account the prior knowledge of aerial imagery. Finally the point cloud is classified into three classes (building, vegetation, and ground) by a rule-based hierarchical approach in the semantic reconstruction step. Experiments on complex urban scene show that our proposed 3-stage approach could generate reasonable reconstruction result robustly and efficiently. By comparing our final semantic reconstruction result with the manually labeled ground truth, classification accuracies from 86.75% to 93.02% are obtained. 相似文献
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The wide applications of CAD/CAM technologies have promoted the development and application of many advanced technologies, such as digital manufacturing, rapid prototyping, enterprise resources planning, computer integrated manufacturing, concurrent engineering, virtual reality, and mass customization. These advanced technologies all need to be supported by three-dimensional (3D) solid models of products. Most enterprises, however, still organize their production using 2D paper drawings, which makes difficulties for the application of these advanced technologies. It is needed to convert engineering paper drawings into 3D solid models for applications. Based on holo-extraction of information from paper drawings, this paper develops a systematic 3D reconstruction method, which simulates an experienced human designer's thinking mode in transforming inaccurate outlines with inaccurate projection relationships in 2D drawings into 3D image, with the aid of Genetic Algorithms. 相似文献
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反向工程中NURBS曲面CAD重构技术研究 总被引:1,自引:0,他引:1
王慧敏 《计算机应用与软件》2009,26(10):81-83,238
CAD几何模型重构技术是反向工程RE(Reverse Engineering)技术的核心,NURBS(Non-Uniform Rational B-Splines)方法因其表示法的形状控制灵活性,在曲面造型和曲面重构中具有重要作用.针对CAD曲面重构技术进行研究,并对NURBS曲面重构提出一种新的构建方法,将每个数据点相对应的有理基函数的参数值最大化,所得函数值作为数据点的参数值来构造NURBS参数曲面.最后通过实例证明了该方法的有效性. 相似文献
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This paper presents a fast and efficient surface reconstruction method from contour data sets. The reconstructed surface is defined as an implicit surface. We need not create any geometric skeleton and the blending of the three dimensional contour functions enables us to avoid the correspondence and the branching problems that occur in geometrical methods. Tests carried out with medical scanner data-sets show that the reconstruction may be performed at interactive rates. 相似文献
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Three-dimensional (3D) reconstruction techniques have been used to obtain the 3D representations of objects in civil engineering in the form of point cloud models, mesh models and geometric models more often than ever, among which, point cloud models are the basis. In order to clarify the status quo of the research and application of the techniques in civil engineering, literature retrieval is implemented by using major literature databases in the world and the result is summarized by analyzing the abstracts or the full papers when required. First, the research methodology is introduced, and the framework of 3D reconstruction techniques is established. Second, 3D reconstruction techniques for generating point clouds and processing point clouds along with the corresponding algorithms and methods are reviewed respectively. Third, their applications in reconstructing and managing construction sites and reconstructing pipelines of Mechanical, Electrical and Plumbing (MEP) systems, are presented as typical examples, and the achievements are highlighted. Finally, the challenges are discussed and the key research directions to be addressed in the future are proposed. This paper contributes to the knowledge body of 3D reconstruction in two aspects, i.e. summarizing systematically the up-to-date achievements and challenges for the applications of 3D reconstruction techniques in civil engineering, and proposing key future research directions to be addressed in the field. 相似文献
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提出了一种基于点与直线关系从透视投影画隐线图建立平面立体线框模型的新方法。给出了基于点线关系的基本约束,根据透视投影画隐线图中隐含的点与直线位置关系建立约束方程,建立一个线性系统,通过求解该线性系统得到平面立体的三维信息。用算例进行验证,得到了平面立体的三维信息。 相似文献