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1.
一种鱼眼镜头成像立体视觉系统的标定方法   总被引:12,自引:0,他引:12  
贾云得  吕宏静  徐岸  刘万春 《计算机学报》2000,23(11):1215-1219
鱼眼镜头成像立体视觉系统在微小型机器人视觉导航和近距离大视场物体识别与定位中有着广泛的应用 .尽管鱼眼镜头摄像机具有很大的视场角 (接近 180°) ,但同时也引入严重的图像变形 ,常规的摄像机标定方法无法使用 .该文提出一种标定鱼眼镜头摄像机立体视觉系统的方法 .在鱼眼镜头变形模型的基础上 ,通过考虑鱼眼镜头成像的径向变形、偏心变形和薄棱镜变形 ,建立了鱼眼镜头成像的精确成像模型 ;然后 ,利用非线性迭代算法 ,精确求解摄像机外部参数、内部参数 .实验表明 ,使用该方法得到的立体视觉系统参数满足精确恢复大场景稠密深度图的要求 .  相似文献
2.
Active,optical range imaging sensors   总被引:6,自引:0,他引:6  
Active, optical range imaging sensors collect three-dimensional coordinate data from object surfaces and can be useful in a wide variety of automation applications, including shape acquisition, bin picking, assembly, inspection, gaging, robot navigation, medical diagnosis, and cartography. They are unique imaging devices in that the image data points explicitly represent scene surface geometry in a sampled form. At least six different optical principles have been used to actively obtain range images: (1) radar, (2) triangulation, (3) moire, (4) holographic interferometry, (5) focusing, and (6) diffraction. In this survey, the relative capabilities of different sensors and sensing methods are evaluated using a figure of merit based on range accuracy, depth of field, and image acquisition time.  相似文献
3.
一种基于局部最大熵的特征匹配算法   总被引:3,自引:1,他引:2  
传统的基于灰度的匹配算法抗噪声能力和抗局部几何变形能力较差,通过图像熵变换,提出了一种新颖的基于局部最大熵的特征匹配算法;通过局部特征点所在区域的相关匹配,获得具有最大可信度的匹配结果。由于匹配只是在特征点之间进行,且在匹配过程中引入外极线和一致性约束条件,从而大大降低了计算消耗和误匹配率,获得了比较理想的表面离散深度图。  相似文献
4.
Active Appearance-Based Robot Localization Using Stereo Vision   总被引:2,自引:0,他引:2  
A vision-based robot localization system must be robust: able to keep track of the position of the robot at any time even if illumination conditions change and, in the extreme case of a failure, able to efficiently recover the correct position of the robot. With this objective in mind, we enhance the existing appearance-based robot localization framework in two directions by exploiting the use of a stereo camera mounted on a pan-and-tilt device. First, we move from the classical passive appearance-based localization framework to an active one where the robot sometimes executes actions with the only purpose of gaining information about its location in the environment. Along this line, we introduce an entropy-based criterion for action selection that can be efficiently evaluated in our probabilistic localization system. The execution of the actions selected using this criterion allows the robot to quickly find out its position in case it gets lost. Secondly, we introduce the use of depth maps obtained with the stereo cameras. The information provided by depth maps is less sensitive to changes of illumination than that provided by plain images. The main drawback of depth maps is that they include missing values: points for which it is not possible to reliably determine depth information. The presence of missing values makes Principal Component Analysis (the standard method used to compress images in the appearance-based framework) unfeasible. We describe a novel Expectation-Maximization algorithm to determine the principal components of a data set including missing values and we apply it to depth maps. The experiments we present show that the combination of the active localization with the use of depth maps gives an efficient and robust appearance-based robot localization system.  相似文献
5.
Extracting View-Dependent Depth Maps from a Collection of Images   总被引:1,自引:0,他引:1  
Stereo correspondence algorithms typically produce a single depth map. In addition to the usual problems of occlusions and textureless regions, such algorithms cannot model the variation in scene or object appearance with respect to the viewing position. In this paper, we propose a new representation that overcomes the appearance variation problem associated with an image sequence. Rather than estimating a single depth map, we associate a depth map with each input image (or a subset of them). Our representation is motivated by applications such as view interpolation and depth-based segmentation for model-building or layer extraction. We describe two approaches to extract such a representation from a sequence of images.The first approach, which is more classical, computes the local depth map associated with each chosen reference frame independently. The novelty of this approach lies in its combination of shiftable windows, temporal selection, and graph cut optimization. The second approach simultaneously optimizes a set of self-consistent depth maps at multiple key-frames. Since multiple depth maps are estimated simultaneously, visibility can be modeled explicitly and disparity consistency imposed across the different depth maps. Results, which include a difficult specular scene example, show the effectiveness of our approach.  相似文献
6.
基于改进双边滤波的Kinect深度图像空洞修复算法研究   总被引:1,自引:0,他引:1  
深度图像的灰度值表征的是物体与摄像头的距离,深度图像在三维场景重建、虚拟视点合成、3D视频技术中起到关键的作用.深度图像有多种获取方法,其中Microsoft公司的Kinect是一种廉价的深度图像获取设备,但产生的深度图像在物体的边缘和遮挡区域往往会产生空洞,不利于后续的研究应用.提出一种基于改进双边滤波法的深度图像修复算法,首先利用直方图确定阈值将深度图像二值化生成空洞Mask掩膜,然后利用改进的双边滤波法对空洞区域进行深度填充,最后利用中值滤波法进行图像平滑,实验结果表明该方法对于原始深度图像的空洞取得了较好的修复效果.  相似文献
7.
Detailed Real-Time Urban 3D Reconstruction from Video   总被引:1,自引:0,他引:1  
The paper presents a system for automatic, geo-registered, real-time 3D reconstruction from video of urban scenes. The system collects video streams, as well as GPS and inertia measurements in order to place the reconstructed models in geo-registered coordinates. It is designed using current state of the art real-time modules for all processing steps. It employs commodity graphics hardware and standard CPU’s to achieve real-time performance. We present the main considerations in designing the system and the steps of the processing pipeline. Our system extends existing algorithms to meet the robustness and variability necessary to operate out of the lab. To account for the large dynamic range of outdoor videos the processing pipeline estimates global camera gain changes in the feature tracking stage and efficiently compensates for these in stereo estimation without impacting the real-time performance. The required accuracy for many applications is achieved with a two-step stereo reconstruction process exploiting the redundancy across frames. We show results on real video sequences comprising hundreds of thousands of frames.  相似文献
8.
随着计算机科学,图像处理,模式识别的快速发展,人们对双目视觉系统和三维创建越来越重视。这些研究和应用在一些领域取得了好的结果。我们研究和设计一套双目视觉系统目的是获得生动的立体图像。而深度图像又是从二维图像恢复到三维图像的关键,因此深度图像的好坏直接影响到三维创建的效果。深度图像的生成与分析越来越受到  相似文献
9.
Obtaining an accurate and precise depth map is the ultimate goal for 3D shape recovery. For depth map estimation, one of the most vital parts is the initial selection of the focus measure and processing the images with the selected focus measure. Although, many focus measures have been proposed in the literature but not much attention has been paid to the factors affecting those focus measures as well as the manner the images are processed with those focus measures. In this paper, for accurate calculation of depth map, we consider the effects of illumination on the depth map as well as the selection of the window size for application of the focus measures. The resulting depth map can further be used in techniques and algorithms leading to recovery of three-dimensional structure of the object which is required in many high-level vision applications. It is shown that the illumination effects can directly result in incorrect estimation of depth map if proper window size is not selected during focus measure computation. Further, it is shown that the images need some kind of pre-processing to enhance the dark regions and shadows in the image. For this purpose, an adaptive enhancement algorithm is proposed for pre-processing. In this paper, we prove that without such pre-processing for image enhancement and without the use of proper window size for the estimation of depth maps, it is not possible to obtain the accurate depth map.  相似文献
10.
We present a real-time implementation of 2D to 3D video conversion using compressed video. In our method, compressed 2D video is analyzed by extracting motion vectors. Using the motion vector maps, depth maps are built for each frame and the frames are segmented to provide object-wise depth ordering. These data are then used to synthesize stereo pairs. 3D video synthesized in this fashion can be viewed using any stereoscopic display. In our implementation, anaglyph projection was selected as the 3D visualization method, because it is mostly suited to standard displays.
Ianir IdesesEmail:
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