基于三视图的三维重建技术的研究现状与展望

在分析三视图在工程领域的作用、传统三维造型方式的不足以及某些现实需求的基础上,讨论了基于三视图的三维重建技术的意义与应用价值。简介了两大类方法的基本原理、发展现状以及存在的瓶颈问题等。通过讨论产生瓶颈问题的原因以及该领域的发展趋势,提出新的重建思路,并展望了基于三视图的三维重建技术的发展方向。     

基于三视图的三维重建技术的研究现状与展望

在分析三视图在工程领域的作用、传统三维造型方式的不足以及某些现实需求的基础上,讨论了基于三视图的三维重建技术的意义与应用价值。简介了两大类方法的基本原理、发展现状以及存在的瓶颈问题等。通过讨论产生瓶颈问题的原因以及该领域的发展趋势,提出新的重建思路,并展望了基于三视图的三维重建技术的发展方向。     

网络CAD技术应用与展望

现代信息社会对设计领域提出了基于信息共享的可视化、集成化、智能化和自动化的要求,开展工程CAD技术在协同设计环境中的应用研究是建立面向数字化产品模型、信息共享与协作的现代设计系统的技术基础之一,本文针对网络CAD技术在及其在工程设计中的应用与发展进行了全面的概述,首先介绍了背景与产生原因,随后说明了相关概念与研究内容,最后阐述了发展趋势、典型系统及主要支撑技术。     

工程设计CAD技术展望

从建筑工程计算机辅助设计的有关概念出发，介绍了我国建筑与结构设计具有代表性的ＣＡＤ软件 功能特点及其发展水平，展望了ＣＡＤ技术发展的一些动态。     

AutoCAD环境中三维立体生成三视图方法研究

主要分析如何在AutoCAD绘图环境下,由三维立体模型生成平面三视图(组合体)的方法。结合具体实例,探讨了用AutoCAD2010建模工具条中命令生成平面三视图的步骤和方法。灵活应用建模工具条可以大大节约建模的时间,提高工作效率,灵活应用AutoCAD建模充分发挥AutoCAD三维功能,AutoCAD生成平面三视图过程不亚于其他三维软件建模,在机械制图课程教学改革中具有一定的实用价值。     

基于无人机三维重建现状模型的风景园林设计研究与教学探索

随着无人机技术在风景园林规划设计中发挥越来越重要的作用,将无人机技术引入风景园林设计和教学已经成为可能。本文通过阐述无人机三维重建技术的概念、技术流程和技术优势、该技术在风景园林设计中的应用以及该技术与风景园林设计教学的结合方式,展示了以无人机三维重建现状模型为结合点,风景园林设计、教学与前沿科学技术的融合。     

基于无人机摄影技术的农村房屋三维重建

针对传统的农村房屋危险性鉴定方法主观性大、耗时费力、难以量化评定等缺点,提出了一种基于无人机平台和数字图像处理技术的农村房屋三维重建方法.该方法首先通过无人机采集房屋表面的彩色图像和深度图像,利用基于SFM的三维重建技术对房屋整体进行重建,并根据重建结果为房屋危险性评估作参考;再通过基于深度图像的局部缺陷三维重建和基于摄影测量的裂缝检测技术对房屋的危险点进行定量测量.结果表明:该技术能快速采集房屋的缺陷信息,同时建立直观精细的房屋模型,对提高检测效率和精度、建立房屋鉴定数据库有重要意义.     

基于Retinex图像增强算法的水下三维重建研究

为了解决传统水下三维重建成本大、设备复杂等问题，本文提出一种结合Retinex图像增强算法和视觉三维重建理论的水下三维重建方案。首先使用Rentinex算法对图像进行处理，恢复目标的原有信息，再将处理前后的水下图像进行特征点提取匹配、稀疏重建、稠密重建和泊松重建等视觉三维重建处理。对比实验结果表明，经Rentinex图像增强算法处理后的图像，可有效改进水下三维重建技术，对现有的水下三维重建技术是一个很好的补充。     

基于建筑图的板三维重建方法研究

在墙、柱、梁识别三维重建的基础上,通过采用C＋＋面向对象设计的方法,针对板的结构特征,提出了分层次、基于封闭性的板结构重建方法,以期进一步提高建筑信息化以及提高算量过程的效率与准确性。     

“三视图的基本投影原理”的教学之我见

三视图不仅是进入《机械制图》这门课程的门槛,而且是在本课程中至关重要。想要画好三视图就必须要把三视图的形成和它的投影规律讲清楚,而左、俯两视图间的"宽相等"和"前后方位"的关系,是三视图投影规律的重点和难点所在。     

三视图在削竹式洞门施工放样中的应用

结合十天高速毛想寨隧道左线削竹式洞门的施工经验,提出了利用三视图指导削竹式洞门施工放样的方法,具体从三视图投影规则的角度对该方法进行了论证,为今后削竹式洞门施工放样积累了经验。     

Automatic reconstruction of 3D building models from scanned 2D floor plans

The overall energy efficiency of existing buildings has to be significantly improved to comply with emerging regulations and to contribute to overcoming current environmental challenges. Many policies aim at accelerating the renovation rate. The effectiveness of renovation actions could be significantly improved through the systematic use of Information and Communication Technologies (ICT) tools and Building Information Modeling (BIM). But these solutions rely on full-fledged digital models, which, for most buildings, are not available. The present article introduces a research work aiming at the development of methods for the generation of 3D building models from 2D plans. The developed prototype is able to extract information from 2D plans and to generate IFC (Industry Foundation Classes)-compliant 3D models that include the main components of the building: walls, openings, and spaces. The article also presents the results of a quantitative assessment of the platform capabilities and performances, relying on a database of 90 real architectural floor plans. The results are very promising and show that such solutions could be key components of future digital toolkits for renovation design.     

Progressive 3D reconstruction of infrastructure with videogrammetry

A number of methods are commonly used today to collect infrastructure's spatial data (time-of-flight, visual triangulation, etc.). However, current practice lacks a solution that is accurate, automatic, and cost-efficient at the same time. This paper presents a videogrammetric framework for acquiring spatial data of infrastructure which holds the promise to address this limitation. It uses a calibrated set of low-cost high resolution video cameras that is progressively traversed around the scene and aims to produce a dense 3D point cloud which is updated in each frame. It allows for progressive reconstruction as opposed to point-and-shoot followed by point cloud stitching. The feasibility of the framework is studied in this paper. Required steps through this process are presented and the unique challenges of each step are identified. Results specific to each step are also presented.     

基于AutoLISP的三维模型快速建立与精度分析

建筑物的三维模型是数字城市重建的重要组成部分,而建筑物高精度三维模型的快速建立一直是三维数字仿真亟待解决的问题。本文通过无协作目标电子全站仪采集建筑的三维坐标,基于AutoLISP实现了数据的导入、建筑物墙面的拟合、特征点的投影及门窗等构件的自动生成,从而快速生成建筑物的三维模型,并对生成的建筑模型进行精度分析。基于AutoLISP构建建筑物的三维模型,大大提高了建模速度;并能有效控制三维建筑模型的质量。     

Image-based 3D scene reconstruction and exploration in augmented reality

Augmented Reality (AR) is an integrated technique of image processing and display system of complex information, which involves real-time computing, motion tracking, pattern recognition, image projection, database linking, feature extraction, and coordinate transformation. In this study, such techniques through Structure From Motion (SFM), Clustering Views for Multi-View Stereo (CMVS), Patch-based Multi-View Stereo (PMVS), and Poisson surface reconstruction were smoothly integrated into a 3D reconstruction system with comparative efficiency in computation. The system can be applied to regular images taken by amateur cameras, smart phones, tablet PCs, and other mobile devices, without need of a priori internal and external camera parameters. To verify the ability of the established reconstruction system, indoor and outdoor objects at various scales, such as a helmet (a small object), a corridor (an indoor medium object), an arbor (outdoor medium object), and a building (outdoor large object) were tested. Through tracking and registration, the reconstructed 3D models were loaded in an AR environment to facilitate displaying, interacting, and rendering that provides AR applications in construction design and management for better and qualitative communication in economical and handy ways.     

Multi-view stereo for weakly textured indoor 3D reconstruction

A 3D reconstruction enables an effective geometric representation to support various applications. Recently, learning-based multi-view stereo (MVS) algorithms have emerged, replacing conventional hand-crafted features with convolutional neural network-encoded deep representation to reduce feature matching ambiguity, leading to a more complete scene recovery from imagery data. However, the state-of-the-art architectures are not designed for an indoor environment with abundant weakly textured or textureless objects. This paper proposes AttentionSPP-PatchmatchNet, a deep learning-based MVS algorithm designed for indoor 3D reconstruction. The algorithm integrates multi-scale feature sampling to produce global-context-aware feature maps and recalibrates the weight of essential features to tackle challenges posed by indoor environments. A new dataset designed exclusively for indoor environments is presented to verify the performance of the proposed network. Experimental results show that AttentionSPP-PatchmatchNet outperforms state-of-the-art algorithms with relative 132.87% and 163.55% improvements at the 10 and 2 mm threshold, respectively, making it suitable for accurate and complete indoor 3D reconstruction.     

标准麻花钻3D建模技术研究

建立麻花钻的三维实体模型是对麻花钻设计、制造、切削性能分析以及对钻削过程进行仿真研究的基础。分析了麻花钻的结构特点,麻花钻前、后刀面的成形原理,利用三维软件Pro/E,建立截形曲线及螺旋轨迹建立前刀面模型;利用锥面刃磨法原理,通过相关刃磨参数,建立后刀面模型。     

3D reconstruction of existing concrete bridges using optical methods

Routine bridge inspections usually consist of visual observations. These inspections are time-consuming and subjective. There is a need to identify new inspection techniques for infrastructure that reduce traffic disturbance, and improve the efficiency and reliability of the acquired data. This study compared the performance of three different imaging technologies for the three-dimensional (3D) geometric modeling of existing structures: terrestrial laser scanning, close-range photogrammetry, and infrared scanning. Each technology was used to assess six existing concrete railway bridges. The technologies were compared in terms of geometric deviations, visualization capabilities, the level of the inspector’s experience, and degree of automation. The results suggest that all methods investigated can be used to create 3D models, however, with different level of completeness. Measurements such as span length, deck widths, etc. can be extracted with good accuracy. Although promising, a full off-site inspection is currently not feasible as some areas of the bridges were difficult to capture mainly due to restricted access and narrow spaces. Measurements based on terrestrial laser scanning were closer to the reality compared to photogrammetry and infrared scanning. The study indicates the no special training is needed for photogrammetry and infrared scanning to generate a 3D geometric model.     

土壤孔隙结构三维重建软件系统的设计与实现

深入探讨了土壤孔隙结构三维重建软件系统的设计思路、核心技术及实现过程,着重论述了三维可视化技术在土壤孔隙空间三维重建中的应用,并用实例验证了该软件系统的功能及可行性。研究结果有望为土壤物理学、土壤微形态学等领域的研究提供一个功能全面、简单易用的软件平台,有助于将该方面研究工作推向深入。