Putting the User in the Loop for Image-Based Modeling

We refer to the task of recovering the 3D structure of an object or a scene using 2D images as image-based modeling. In this paper, we formulate the task of recovering the 3D structure as a discrete optimization problem solved via energy minimization. In this standard framework of a Markov random field (MRF) defined over the image we present algorithms that allow the user to intuitively interact with the algorithm. We introduce an algorithm where the user guides the process of image-based modeling to find and model the object of interest by manually interacting with the nodes of the graph. We develop end user applications using this algorithm that allow object of interest 3D modeling on a mobile device and 3D printing of the object of interest. We also propose an alternate active learning algorithm that guides the user input. An initial attempt is made at reconstructing the scene without supervision. Given the reconstruction, an active learning algorithm uses intuitive cues to quantify the uncertainty of the algorithm and suggest regions, querying the user to provide support for the uncertain regions via simple scribbles. These constraints are used to update the unary and the pairwise energies that, when solved, lead to better reconstructions. We show through machine experiments and a user study that the proposed approach intelligently queries the users for constraints, and users achieve better reconstructions of the scene faster, especially for scenes with textureless surfaces lacking strong textural or structural cues that algorithms typically require.     

基于OpenGL的三维建筑设计组件的设计与实现

本文提出了一种面向对象的支持三维图形可重用的组件层次设计方法，分析了组件的性能、设计方法和图元算法，实现了基于OpenGL的支持三维虚拟场景、建模和运动仿真的组件设计，描述了实体的运动层次链接关系和数据结构，并实现了虚拟环境的建筑物建模和运动仿真。     

基于一种形式化方法的3D虚拟祭祀场景建模语言与环境

针对现有三维（3D）场景建模方法普遍存在着业务耦合度高,复杂场景对象属性和特征描述能力不强、不丰富,不能很好地解决3D虚拟祭祀场景建模的问题,提出了基于一种形式化方法的场景建模语言与建模环境。首先,通过引入场景对象、场景对象模板、场景对象模板属性三个层次的概念对3D虚拟祭祀场景的构成特点进行了详细分析;然后,提出了一种基于形式化松耦合、属性描述能力强、语言通用性灵活的3D场景建模语言;其次,设计了场景建模语言的操作,使得该语言可以通过应用程序编程接口（API）调用的方式完成编辑,实现了该语言对界面化建模的支持;最后定义了一套该语言的可扩展标记语言（XML）映射方法,使场景建模结果以XML文本格式进行存储,提升了建模结果的可复用性,并展示了建模的应用案例。应用结果表明,所提方法在增强新增数据类型特性支持的同时完善了序列属性、结构体属性类型的描述,使得对复杂场景对象属性和特征描述能力的通用性、灵活性更强,可复用程度高,在界面化建模支持程度上优于Su等（束搏,邱显杰,王兆其.基于图像的几何建模技术综述.计算机研究与发展,2010,47（3）：549-560）提出的方法,解决了3D虚拟祭祀场景建模问题。所提方法同样适用于其他组成粒度低、属性成分多、业务耦合度高的3D场景建模,并能提升建模效率。     

INCOME/STAR: Methodology and tools for the development of distributed information systems

INCOME/STAR is an experimental environment for the cooperative development of distributed information systems. This paper presents some of INCOME/STAR's innovative features in the area of information systems engineering: First a new type of high-level Petri nets, so-called Nested Relation/Transition nets (NR/T-nets), is described. NR/T-nets allow the modeling of concurrent processes and related complex structured objects in distributed business applications. New concepts for entity and relationship clustering were developed to support a stepwise top-down approach for Entity/Relationship based object modeling. Distributed multi-user simulation and prototyping are used for the evaluation and analysis of NR/T-nets and the involved object schema. Finally, ProMISE — an evolutionary process model for information system development — is introduced. A role-based groupware component is part of the INCOME/STAR architecture to support communication, organization and social interaction in development projects.     

实时三维图形平台BH_GRAPH

BH_GRAPH是一个面向视景仿真类应用系统开发人员、支持实时三维图形开发与运行的基础软件平台．它提供可扩展的软件体系结构、标准化的场景管理机制、高效率的场景处理方法、方便易用的应用程序接口,为三维图形应用系统的快速开发、高效运行提供完整的技术支撑．BH_GRAPH主要由三维视景绘制引擎、三维对象建模工具、三维场景布置工具以及一系列关键技术构成．概要介绍了BH—GRAPH各主要组成部分的软件结构、基本功能和技术特点．     

3D modeling of multiple-object scenes from sets of images

This paper proposes a new approach for multi-object 3D scene modeling. Scenes with multiple objects are characterized by object occlusions under several views, complex illumination conditions due to multiple reflections and shadows, as well as a variety of object shapes and surface properties. These factors raise huge challenges when attempting to model real 3D multi-object scene by using existing approaches which are designed mainly for single object modeling. The proposed method relies on the initialization provided by a rough 3D model of the scene estimated from the given set of multi-view images. The contributions described in this paper consists of two new methods for identifying and correcting errors in the reconstructed 3D scene. The first approach corrects the location of 3D patches from the scene after detecting the disparity between pairs of their projections into images. The second approach is called shape-from-contours and identifies discrepancies between projections of 3D objects and their corresponding contours, segmented from images. Both unsupervised and supervised segmentations are used to define the contours of objects.     

A complete and extendable approach to visual recognition

A framework for 3D object recognition is presented. Its flexibility and extensibility are accomplished through a uniform, parallel, and modular recognition architecture. Concurrent and stacked parameter transforms reconstruct a variety of features from the input scene. At each stage, constraint satisfaction networks collect and fuse the evidence obtained through the parameter transforms, ensuring a globally consistent interpretation of the input scene and allowing for the integration of diverse types of information. The final interpretation of the scene is a small consistent subset of the many initial hypotheses about partial features, primitive features, feature assemblies, and 3D objects computed by the various parameter transforms. A complete, integrated, and implemented system that extracts planar surfaces, patches of quadrics of revolution, and planar intersection curves of these surfaces from a depth map viewing 3D objects is described. Experimental results on the recognition behavior of the system are presented     

铁路仿真通用三维可视化系统建模研究

铁路仿真通用三维可视化系统是一个通用可视化平台,用户以三维漫游的方式查看铁路仿真数据。在分析仿真业务需要和铁路三维场景的数据特性的基础上,本文对系统建模进行研究,设计了系统框架和模块,给出了三维场景漫游控制流程。实验室初步试验证明,这个概要模型时可行的。     

基于通用模型文件的城市三维景观面向对象可视化方法

三维模型文件的.Obj格式是一种通用的开放式模型格式。该文在分析OBJ模型文件结构的基础上,针对城市空间信息应用的特点,设计了一种通用的三维模型对象的类结构,利用该类建立的三维模型对象,可以直接获取OBJ文件中的几何、材质等三维实体信息。对象中的可视化成员方法利用模型数据和OpenGL图形处理技术实现对三维模型的真实感显示。三维通用模型和面向对象思想的引入,比较好地解决了城市三维景观中复杂模型的建模和可视化问题,有利于对复杂场景中大量三维模型的有效管理和组织。     

基于CV／CAD的三维物体几何建模

在虚拟现实等技术领域中,都涉及到由现实世界中的实际景物建立对应的计算机描述的虚拟景物的问题,为此提出了利用计算机视觉与CAD几何建模技术相结合的三维珠体建模途径,首先通过编码光栅方法获取三维物体的深度图象,并采用数学形态学的方法加以分割,然后利用代数曲面拟合手段对分割后的三维曲面片进行重建,并使用CAD几何建模工具由重建的曲面片构成物体的几何模型,该文给出了初步的实验结果,证明所提出的技术途径基本可行。     

三维雕刻机的远程控制技术研究及系统实现

介绍了雕刻机三维模型设计制作中的主要技术，并对虚拟场景的构建和优化作了说明。在三维雕刻机的模拟仿真中，对工件结构设计和NC代码解释执行等技术作了深入探讨。通过WINSOCK技术实现了对雕刻机的远程控制，并采用自适应端到端的QoS控制技术，在三维雕刻机的远程控制中实现了流畅的视频传输。     

Separating semantics from rendering: a scene graph based architecture for graphics applications

A large number of rendering and graphics applications developed in research and industry are based on scene graphs. Traditionally, scene graphs encapsulate the hierarchical structure of a complete 3D scene, and combine both semantic and rendering aspects. In this paper, we propose a clean separation of the semantic and rendering parts of the scene graph. This leads to a generally applicable architecture for graphics applications that is loosely based on the well-known Model-View-Controller (MVC) design pattern for separating the user interface and computation parts of an application. We explore the benefits of this new design for various rendering and modeling tasks, such as rendering dynamic scenes, out-of-core rendering of large scenes, generation of geometry for trees and vegetation, and multi-view rendering. Finally, we show some of the implementation details that have been solved in the process of using this software architecture in a large framework for rapid development of visualization and rendering applications.     

基于UML的三维建模系统多方案动画设计

为使用户可以在一个场景中观察某个对象的多个动画,基于统一建模语言技术并采用“整体-局部”方法,给出三维建模系统动画实现过程与所需模块。以关键帧管理为主线,结合面向对象设计方法,给出实现细节的用例分析。对关键帧采用双结点十字链表结构,提供多方案动画调试功能。根据局部功能给出实现类的设计,为进一步代码实现提供依据。     

真实场景中基于体表示的目标外形和纹理获取

传统的基于图像的三维重建方法中,图像间的相关特征匹配是影响重建模型质量和精度的主要因素之一。提出一种基于体表示的真实目标的重建方法,回避了二维图像间的特征匹配问题,简化了建模的复杂度。该方法首先提取目标物的轮廓信息;其次单向单层遍历场景空间中目标物的最小三维包围盒,利用目标物固有的颜色信息不变性判断体元反向投影的一致性,从而获取目标的三维信息;最后利用获取的三维信息绘制得到真实目标的逼真模型。实验结果表明该方法建模精度较高,真实感强。     

3D目标检测进展综述

目标检测算法应用广泛,一直是计算机视觉领域备受关注的研究热点。近年来,随着深度学习的发展,3D图像的目标检测研究取得了巨大的突破。与2D目标检测相比,3D目标检测结合了深度信息,能够提供目标的位置、方向和大小等空间场景信息,在自动驾驶和机器人领域发展迅速。文中首先对基于深度学习的2D目标检测算法进行概述;其次根据图像、激光雷达、多传感器等不同数据采集方式,分析目前具有代表性和开创性的3D目标检测算法;结合自动驾驶的应用场景,对比分析不同3D目标检测算法的性能、优势和局限性;最后总结了3D目标检测的应用意义以及待解决的问题,并对3D目标检测的发展方向和新的挑战进行了讨论和展望。     

基于X3D的虚拟场景建模技术

Web3D联盟发布的X3D标准作为下一代面向互联网的三维图形描述规范,已经被ISO批准成为国际标准,越来越广泛地应用于教育、训练、模拟等方面。该文从介绍虚拟现实技术的发展情况入手,深入分析了X3D规范的文件结构和语法结构。提出了利用X3D规范进行虚拟现实场景建模和系统优化的方法,对于提高景物建模的真实感和降低景物建模的复杂度都有重要的现实意义。     

基于Web3D的虚拟场景漫游的设计与实现

介绍了Java3D与VR相结合的Web3D应用；采用了三层式的Client／Server结构和分布计算模型设计系统体系结构，提出了在Java3D中获取场景对象实例的方法，给出了在Java3D场景中实现虚拟场景中漫游的方法。采用Java3D实现与用户交互虚拟三维场景，并给出了部分实现细节。     

基于Web3D的虚拟场景漫游的设计与实现

介绍了Java3D与VR相结合的Web3D应用;采用了三层式的Client/Server结构和分布计算模型设计系统体系结构,提出了在Java3D中获取场景对象实例的方法,给出了在Java3D场景中实现虚拟场景中漫游的方法。采用Java3D实现与用户交互虚拟三维场景,并给出了部分实现细节。     

Distributed intelligence for multi-camera visual surveillance

Latest advances in hardware technology and state of the art of computer vision and artificial intelligence research can be employed to develop autonomous and distributed monitoring systems. The paper proposes a multi-agent architecture for the understanding of scene dynamics merging the information streamed by multiple cameras. A typical application would be the monitoring of a secure site, or any visual surveillance application deploying a network of cameras. Modular software (the agents) within such architecture controls the different components of the system and incrementally builds a model of the scene by merging the information gathered over extended periods of time. The role of distributed artificial intelligence composed of separate and autonomous modules is justified by the need for scalable designs capable of co-operating to infer an optimal interpretation of the scene. Decentralizing intelligence means creating more robust and reliable sources of interpretation, but also allows easy maintenance and updating of the system. Results are presented to support the choice of a distributed architecture, and to prove that scene interpretation can be incrementally and efficiently built by modular software.     

OpenGL Optimizer及其在大规模地形场景漫游中的应用

本文介绍了OpenGL Optimizer的强大功能和体系结构,针对组成地形场景地貌和点、线、面三类地物,阐明了运用该三维引擎创建大规模地形场景的方法,并论述了应用程序的性能优化策略。实例表明应用OpenGL Optimizer在保持场景真实感的情况下大大提高了场景的渲染速度,达到了大规模地形场景实时漫游的要求。