由单幅二维灰度图像重构物体表面形状*

鉴于目前很少有论文讨论完整的由单幅二维灰度图像重构物体表面形状的算法,包括它的控制参数的估计及算法的实现,介绍了一种完整的SFS算法.它在考虑自遮掩影响的情况下,有效地估计了SFS算法中涉及的各种控制参数,并引入亮度约束、灰度梯度约束和可积性约束,计算出表面高度和表面向量,实现三维重构.与传统的算法相比,本算法无论是在速度还是在精度方面都达到了比较高的水平,具有一定的应用前景.最后还指出了在MATLAB中实现需要注意的问题.     

单幅图像三维表面重建的算法研究与实现

以单幅二维图像为研究对象,应用SFS的基本理论,首先对二维图像进行了光照的倾角和偏角的估计,在光源坐标系下计算出物体每一点的表面梯度;之后,旋转坐标系,在观察坐标系下得到物体的表面梯度;最后采用三点辛普森公式求出物体表面的高度。整个算法流程简单,求解层次分明,重构满意度较高。     

Target recognition via 3D object reconstruction from image sequence and contour matching

This paper proposes an automatic target recognition (ATR) system based on the three-dimensional (3D) reconstruction of the target from an image sequence. The main contribution of this work is twofold: (1) we present a modified voxel coloring reconstruction algorithm and (2) we employ the 3D reconstructed target model to generate the front and side target templates at zero depression angle to be used in the target recognition process. Target recognition is performed by matching the generated templates to a library using a subpixel contour matching algorithm. Experimental results on simulated scenes show the accuracy of the approach presented in this paper.     

Symmetry-seeking models and 3D object reconstruction

We propose models of 3D shape which may be viewed as deformable bodies composed of simulated elastic material. In contrast to traditional, purely geometric models of shape, deformable models are active—their shapes change in response to externally applied forces. We develop a deformable model for 3D shape which has a preference for axial symmetry. Symmetry is represented even though the model does not belong to a parametric shape family such as (generalized) cylinders. Rather, a symmetry-seeking property is designed into internal forces that constrain the deformations of the model. We develop a framework for 3D object reconstruction based on symmetry-seeking models. Instances of these models are formed from monocular image data through the action of external forces derived from the data. The forces proposed in this paper deform the model in space so that the shape of its projection into the image plane is consistent with the 2D silhouette of an object of interest. The effectiveness of our approach is demonstrated using natural images.     

快速数字影像重建的2维/3维医学图像配准

目的 针对2D/3D医学图像配准过程中数字影像重建技术(DRR)生成图像和相似性程度测量两个步骤计算量大、耗时较长这一问题,提出了一种基于Bresenham直线生成算法改进的模式强度与梯度相结合的混合配准算法.方法 首先利用Bresenham直线生成算法原理改进传统光线投射算法(Ray-Casting),完成DRR图像的生成;其次模式强度与梯度相结合并引入多分辨率策略来降低相似性测度的计算复杂度;最终利用改进的鲍威尔优化算法对参数进行优化,完成整个配准过程.结果 实验结果表明,改进的混合配准算法与基于相关系数、互信息和模式强度的配准算法相比,配准效率大幅提升.模拟配准实验和临床配准实验完成时间分别为76.2 s和64.9 s,比传统配准算法效率提升3~6倍.结论 提出的算法在保证配准精度和高鲁棒性的前提下,大幅度地提高了2D/3D医学图像配准算法的运算速度,可以满足临床上精确引导手术进行的实时性要求.     

Single image 3D object reconstruction based on deep learning: A review

Multimedia Tools and Applications - The reconstruction of 3D object from a single image is an important task in the field of computer vision. In recent years, 3D reconstruction of single image...     

单幅植物叶片图像的3维重建

目的 植物叶片形态复杂,在虚拟场景中很难真实表现。为了从信息量有限的单幅图像中恢复植物叶片的3维形状,本文基于从明暗恢复形状（shape from shading,SFS）的方法,利用亮度统计规律和植物形态特征恢复叶片的3维形状。方法 在SFS的基础上,设计基于图像骨架的距离场偏置加强表面细节;针对SFS对恢复宏观几何形状的不足,提出根据图像亮度统计分布选取控制点控制表面宏观形状变化,并利用叶片中轴的距离场约束恢复宏观几何形状,每种方法对于表面宏观几何形状恢复的权重基于恢复的反射图和输入图像间的相似度设定;将表面细节添加到宏观几何形状上得到目标对象的3维形状。结果 选取植物叶片图像进行实验,并与其他方法进行比较,实验结果表明本文方法增强了表面细节显示,并有明显的宏观几何形状变化。同时为了验证本文方法对其他物体表面细节恢复的适用性,分别对硬币和恐龙恢复表面细节,实验结果表明提出的增强表面细节的方法同样适用于其他物体。结论 针对单幅植物叶片图像的3维重建,在SFS的基础上提出了根据骨架特征加强表面细节,根据图像亮度统计分布和叶片中轴距离场约束共同恢复表面宏观几何形状的算法,实验结果验证了本文方法的可行性。     

用单数码相机实现物体表面的三维重建

根据由运动重建物体结构的原理,设计了一个简便易操作的三维重建系统,具体做法是:先用张氏标定法求得内参数矩阵,然后在两个不同的未知位置拍摄物体得到两幅图像,经立体匹配后,利用图像特征点的对应关系求解基本矩阵和本质矩阵,分解本质矩阵获得两个拍摄位置确定的摄像机运动参数(旋转矩阵和平移向量),进而求出相机在两个位置的投影矩阵,最后用三角法计算出物体表面特征点的三维坐标并在OpenGL中重建物体表面.和传统的立体视觉系统相比,本系统只需要一台数码相机和平面方格模板就可以实现三维重建,因此适用于普通相机用户.     

3D object model reconstruction from image sequence based on photometric consistency in volume space

This paper presents a system that can reconstruct a photorealistic 3D object model from an image sequence captured at arbitrary viewpoints. The whole system consists of four steps: camera calibration, volumetric modeling, polygonal model formation and texture mapping. We adopt the shape-from-silhouette approach for volumetric modeling. There are two common types of object surface that are difficult to reconstruct—textureless surface and concave surface. To tackle the problems, we propose to perform the volumetric modeling based on the constraints of viewpoint proximity and photometric consistency in the volume space. The volumetric model is converted to the mesh model for efficient manipulation. Finally, the texture map is generated from the image sequence to give the 3D model a photorealistic appearance. Some reconstructed object models are presented to demonstrate the superior performance of our system as compared with the conventional modeling technique based on the photo-consistency in the image space.     

光截法旋转式物体三维重构

本文依据计算机视觉的理论,采用光截法,搭建了一个旋转物体三维重构实验平台。探讨了摄像机及回转台中心轴的标定和空间坐标转换还原工作。并以表面不平的小纸杯为对象进行了具体实验,在MATLAB下对其进行了图像处理获得物体空间三维数据,并将其三维显示出来,获得了较满意的结果。     

3D corrective nose reconstruction from a single image

There is a steadily growing range of applications that can benefit from facial reconstruction techniques, leading to an increasing demand for reconstruction of high-quality 3D face models. While it is an important expressive part of the human face, the nose has received less attention than other expressive regions in the face reconstruction literature.When applying existing reconstruction methods to facial images, the reconstructed nose models are often inconsistent with the desired shape and ex...     

立体视频对象分割及其三维重建算法研究*

为更加有效分析立体视频对象,本文提出了一种基于离散冗余小波变换的立体视频对象分割算法,首先采用离散冗余小波变换提取特征点结合DT网格技术的视差估计方法,获得了可靠的视差场,再利用视差信息对立体视频中静止对象进行分割。对于立体视频序列中的运动对象,采用离散冗余小波提取运动区域的方法进行分割。实验结果表明,本算法对有重叠的多视频对象具有较好的分割效果,可同时分割静止物体和运动物体,具有较好的精确性和鲁棒性。对于分割出的立体视频对象,结合深度信息对其进行三维重建,得到较好的三维效果。     

Multiresolution volumetric 3D object reconstruction for collaborative interactions

Within the framework of collaborative interactions with 3D numerical copies of real objects inserted in virtual environments, this paper tackles the issue of 3D object reconstruction from multiple calibrated cameras. After examining the various constraints related to collaborative systems, we propose comprehensive, state of the art 3D reconstruction techniques. The main families of approaches are here identified, described, and discussed in detail. An analysis of the literature shows that there is a lack of methods that are able to respond to the needs of the collaborative interaction applications, and that perform adequately in terms of computation time and reconstruction accuracy. Accordingly, we propose a new multiresolution volumetric approach that is able to obtain numerical copies of real objects at multiple resolutions. Experimental results demonstrate that the proposed approach provides accurate reconstructions at reasonable, interactive computation times. The use of the proposed approach for progressive insertion of reconstructed objects in the prototype interfaces MOWGLI and Spin-3D developed by FranceTelecom R&D is also illustrated. The text was submitted by the authors in English. Rachid Guerchouche. Was born in Algeria in 1979. He received an Engineer Degree in electronics from the National Polytechnic School of Algiers, Algeria in June 2004, and a research Masters Degree in Virtual Reality and Complex Systems Engineering from Université Evry-Val d’Essonne (France) in June 2005. He is currently a PhD student jointly in the ARTEMIS Department at TELECOM & Management SudParis and in the VIA Project Unit of the IRIS Laboratory at France Télécom R&D. Olivier Bernier. Was born in 1964. He received the diploma of the Ecole Polytech-nique (Palaiseau, France) in 1986 and the diploma of the Ecole Nationale Supérieure des Télécommunications (Paris, France) in 1988. Since this date, he has worked as a Research Engineer at Orange Labs-FT R&D, the research center of France Telecom. His areas of interest are computer vision, statistical learning and pattern recognition, in particular applied to advanced human machine interfaces. Titus Zaharia. Received an Engineer Degree in Electronics and the Masters Degree in Electronics from University POLITEHNICA (Bucharest, Romania) in 1995 and 1996, respectively. In 2001, he obtained a PhD degree in Mathematics and Computer Science from University Paris V—René Descartes (Paris, France). He then joined the ARTEMIS Department at TELECOM & Management SudParis as a research engineer, and became an Associate Professor in 2002. His research interests concern visual content indexing and coding, and include feature extraction, image and video segmentation, motion detection and estimation, 2D/3D reconstruction, virtual character modelling and animation, virtual/augmented reality, digital interactive TV, calibration techniques, and color image processing. Titus Zaharia is a member of SPIE.     

基于单张图像的三维人脸重建

利用一种基于法线的模型变形方法,从单张图像重建高质量的三维人脸.利用球谐函数和一个初始参考模型计算得到模型上每个顶点的法线,利用法线使参考模型变形.实验结果表明:提出的算法可以从单幅图像重建具有细节的高质量三维人脸.     

3D object reconstruction by point coordinates of 2D line drawings

It is a research subject in computer vision to 3D reconstruction of an object represented by a single 2D line drawing.Previous works on 3D reconstruction from 2D line drawings focus on objects with lines,plane,view,and so on.This paper mainly studies the 3D reconstruction from 2D line drawings.Besides,a new approach is proposed:it is that for the research of the point coordinates of 2D line drawings,so as to achieve the object reconstruction by the reconstruction of point coordinates.The reconstruction process includes:① the collection of point coordinates (X,Y) of 2D line drawings;② the derivation of mathematical formula about the reconstruction of the point of 2D line drawings,and calculating the corresponding point of the 3D coordinates;③ the regeneration of 3D graphics with 3D points;④ analyze error by the proportional of parallel of axonometric projection,in order to prove the accuracy of the method.     

3D object retrieval via range image queries in a bag-of-visual-words context

3D object retrieval based on range image queries that represent partial views of real 3D objects is presented. The complete 3D models of the database are described by a set of panoramic views, and a Bag-of-Visual-Words model is built using SIFT features extracted from them. To address the problem of partial matching, we suggest a histogram computation scheme, on the panoramic views, that represents local information by taking into account spatial context. Furthermore, a number of optimization techniques are applied throughout the process for enhancing the retrieval performance. Its superior performance is shown by evaluating it against state-of-the-art methods on standard datasets.     

大规模室外图像3维重建技术研究进展

基于图像的3维重建旨在从一组2维多视角图像中精确地恢复真实场景的几何形状,是计算机视觉和摄影测量中基础且活跃的研究课题,具有重要的理论研究意义和应用价值,在智慧城市、虚拟旅游、数字遗产保护、数字地图和导航等领域有着广泛应用。随着图像采集系统（智能手机、消费级数码相机和民用无人机等）的普及和互联网的高速发展,通过搜索引擎可以获取大量关于某个室外场景的互联网图像。利用这些图像进行高效鲁棒准确的3维重建,为用户提供真实感知和沉浸式体验已经成为研究热点,引发了学术界和产业界的广泛关注,涌现了多种方法。深度学习的出现为大规模室外图像的3维重建提供了新的契机。首先阐述大规模室外图像3维重建的基本串行过程,包括图像检索、图像特征点匹配、运动恢复结构和多视图立体。然后从传统方法和基于深度学习的方法两个角度,分别系统全面地回顾大规模室外图像3维重建技术在各重建子过程中的发展和应用,总结各子过程中适用于大规模室外场景的数据集和评价指标。最后介绍现有主流的开源和商业3维重建系统以及国内相关产业的发展现状。     

A function space model for digital image sampling and its application in image reconstruction

A general mathematical model for digital signal processing, which is based onL^p function spaces, is introduced. This model is used to derive a new class of reconstruction filters for the reconstruction ofN-dimensional images which are not necessarily band-limited. A basic proposition in this work is that the best reconstruction algorithm will depend on the pre-sample filter (or point spread) function. The reconstruction filters described here are optimal in the sense that they result in a reconstructed image which is as close as possible, with respect to a given measure of fidelity, to the unsampled image. The filter is similar in form to the optimal filter derived byPeterson and Middleton (Inform. and Control5, 1962, 279–323) in their comprehensive paper on multidimensional sampling. However the reconstruction filter of Peterson and Middleton is optimal for random fields, whereas the filter described here is optimal for individual images. The optimal reconstruction filter has certain practical advantages over empirically derived reconstruction methods such as cubic interpolation. One of these advantages is that the method produces positive-valued images without loss of image resolution. The performance of the optimal reconstruction filter can be understood without reference to aliasing and truncation errors and is quantified in terms of a simple error metric.     

面向图像三维重建的无人机航线规划

随着无人机技术的发展,无人机序列影像三维重建越来越受到人们的关注。为完整重建任务区域的三维模型并减少无人机飞行功耗,提出一种面向图像三维重建的无人机航线规划算法。针对凸多边形任务区域,在图像重叠度和时间连续性的要求下,基于光栅法规划扫描航线并结合最佳扫描方向使得转弯次数最少。借助Gazebo仿真平台,对比验证了无人机按照该算法规划的航线飞行时功耗更小,且拍摄得到的序列影像能够重建任务区域三维模型。     

三维物体表面重建的分支处理算法研究

根据平面点集Delaunay三角剖分的特性,将Delaunay三角剖分应用到分支问题上,改进和实现了一种分支问题处理算法。将相邻层轮廓线投影到同一个剖面上形成一个带约束边的平面点集,并将它们Delaunay三角化,根据这些三角形组来生成新的轮廓线,使轮廓线一一对应。实验结果表明该算法实现的效果较符合实际情况,能有效地处理各种不同情况。