检索结果-内蒙古大学图书馆

conference on Computer vision and Pattern Recognition (CvPR)

作者： v. verma R. Kumar S. Hsu Sarnoff Corporation USA Canesta Inc. USA

This paper presents a method to detect and construct a 3D geometric model of an urban area with complex buildings using aerial LIDAR (Light Detection and Ranging) data. The LIDAR data collected from a nadir direction is a point cloud containing surface samples of not only the building roofs and terrain but also undesirable clutter from trees, cars, etc. The main contribution of this work is the automatic recognition and estimation of simple parametric shapes that can be combined to model very complex buildings from aerial LIDAR data. The main components of the detection and modeling algorithms are (i) Segmentation of roof and terrain points. (ii) Roof topology Inference. We introduce the concept of a roof-topology graph to represent the relationships between the various planar patches of a complex roof structure. (iii) Parametric roof composition. Simple parametric roof shapes that can be combined to create a complex roof structure of a building are recognized by searching for sub-graphs in its roof-topology graph. (iv) Terrain Modeling. The terrain is identified and modeled as a triangulated mesh. Finally, we provide experimental results that demonstrate the validity of our approach for rapid and automatic building detection and geometric modeling with real LIDAR data. We are able to model cities and other urban areas at the rate of about 10 minutes per sq. mile on a low-end PC.

关键词： Laser radar Buildings Shape Solid modeling Urban areas Cities and towns image reconstruction Urban planning Computer vision image edge detection

来源：评论

学校读者我要写书评

暂无评论

Accurate Event-Driven Motion Compensation Incorporating All Detected Events

Accurate Event-Driven Motion Compensation Incorporating All ...

引用

IEEE Symposium on Nuclear Science (NSS/MIC)

作者： A. Rahmim K. Dinelle J. C. Cheng M. A. Shilov W. P. Segars O. G. Rousset B. M. W. Tsui D. F. Wong v. Sossi Division of Nuclear Medicine Department of Radiology Johns Hopkins University Baltimore MD USA Department of Physics and Astronomy University of British Columbia Vancouver BC Canada Division of Med. Imaging Physics Department of Radiology Johns Hopkins University Baltimore MD USA

This work develops and investigates a formalism for accurate motion-compensated reconstruction, including elaborate consideration of scattered and random coincidences, which at the same time is particularly feasible in the context of high-resolution PET. The method takes into consideration normally-detected projection data which are not detected due to motion. Furthermore, it incorporates information from all detected events, particularly those which, following correction for motion, fall outside the Fov (e.g. axially or through detector gaps), thus satisfying a mathematical requirement, elaborated in the text, that would allow accurate motion averaging of sensitivity factors in image-space (as opposed to projection-space). The proposed method has been extensively validated using phantom experiments as well as realistic simulations of a new mathematical brain phantom developed in this work.

关键词： Motion compensation Event detection Motion detection image reconstruction Positron emission tomography Detectors Scattering Imaging phantoms Spatial resolution Motion estimation

来源：评论

学校读者我要写书评

暂无评论

3D reconstruction of localized objects from radiographs and based on multiresolution and sparsity

3D reconstruction of localized objects from radiographs and ...

引用

IEEE International conference on image Processing (ICIP 2005)

作者： Soussen, C Idier, J CNRS LIMSI F-91403 Orsay France

ISBN: (纸本)0780391349

We address the reconstruction of a 3D image from a set of incomplete X-ray tomographic data. In the case where the image is composed of one or several objects lying in a uniform background, we define a sparse parameterization by considering the active voxels, i.e., the voxels that do not lay inside the background. Estimation of the active voxel densities is performed using the maximum a posteriori (MAP) estimator. In order to implement sparse parameter estimation, we design an original multiresolution scheme, which handles coarse to fine resolution images. This scheme affords automatic selection of active voxels at each resolution level, and provides a drastic decrease of the computation time. We finally show the performance of our method on synthetic data.

关键词： image reconstruction

来源：评论

学校读者我要写书评

暂无评论

Process reconstruction from incomplete and/or inconsistent data

引用

EUROPEAN PHYSICAL JOURNAL D 2005年第2期32卷 215-222页

作者： Ziman, T Plesch, M Buzek, v Slovak Acad Sci Res Ctr Quantum Informat Bratislava 84511 Slovakia Masaryk Univ Fac Informat Brno 60200 Czech Republic

We analyze how an action of a qubit channel (map) can be estimated from the measured data that are incomplete or even inconsistent. That is, we consider situations when measurement statistics is insufficient to determine consistent probability distributions. As a consequence either the estimation (reconstruction) of the channel completely fails or it results in an unphysical channel (i.e., the corresponding map is not completely positive). We present a regularization procedure that allows us to derive physically reasonable estimates (approximations) of quantum channels. We illustrate our procedure on specific examples and we show that the procedure can be also used for a derivation of optimal approximations of operations that are forbidden by the laws of quantum mechanics (e.g., the universal NOT gate).

关键词： Quantum mechanics Quantum communication State reconstruction, quantum tomography

来源：评论

学校读者我要写书评

暂无评论

Scale-invariant registration of monocular endoscopic images to CT-scans for sinus surgery

引用

MEDICAL image ANALYSIS 2005年第5期9卷 413-426页

作者： Burschka, D Li, M Ishii, M Taylor, RH Hager, GD Johns Hopkins Univ CIRL Baltimore MD 21218 USA Johns Hopkins Univ CISST Baltimore MD 21218 USA Johns Hopkins Univ Dept Otolaryngol Baltimore MD 21218 USA

In this paper, we present a novel method for intra-operative registration directly from monocular endoscopic images. This technique has the potential to provide a more accurate surface registration at the surgical site than existing methods. It can operate autonomously from as few as two images and can be particularly useful in revision cases where surgical landmarks may be absent. A by-product of video registration is an estimate of the local surface structure of the anatomy, thus providing the opportunity to dynamically update anatomical models as the surgery progresses. Our approach is based on a previously presented method [Burschka, D., Hager, G.D., 2004. v-GPS (SLAM): - vision-based inertial system for mobile robots. In: Proceedings of ICRA, 409-415] for reconstruction of a scaled 3D model of the environment from unknown camera motion. We use this scaled reconstruction as input to a PCA-based algorithm that registers the reconstructed data to the CT data and recovers the scale and pose parameters of the camera in the coordinate frame of the CT scan. The result is used in an ICP registration step to refine the registration estimates. The details of our approach and the experimental results with a phantom of a human skull and a head of a pig cadaver are presented in this paper. (c) 2005 Elsevier B.v. All rights reserved.

关键词： image registration monocular reconstruction vision-based SLAM sinus surgery

来源：评论

学校读者我要写书评

暂无评论

Process reconstruction from incomplete and/or inconsistent data

Process reconstruction from incomplete and/or inconsistent d...

引用

conference on Quantum Information with Atoms Ions and Photons

作者： Ziman, T Plesch, M Buzek, v Slovak Acad Sci Res Ctr Quantum Informat Bratislava 84511 Slovakia Masaryk Univ Fac Informat Brno 60200 Czech Republic

关键词： Probability distributions

来源：评论

学校读者我要写书评

暂无评论

Seismic image reconstruction using complex wavelets

Seismic image reconstruction using complex wavelets

引用

conference on Computational Imaging III

作者： Miller, MA Kingsbury, NG Hobbs, RW Univ Cambridge Dept Engn Cambridge CB2 1PZ England

ISBN: (纸本)0819456470

The aim of seismic imaging is to reconstruct subsurface reflectivity from scattered acoustic data. In standard reconstruction techniques, the reflectivity model parameters are usually defined as a grid of point scatterers over the area or volume of the subsurface to be imaged. We propose an approach to subsurface imaging using the Dual Tree Complex Wavelet Transform (DT-CWT) as a basis for the reflectivity. This basis is used in conjunction with an iterative optimization which frames the problem as a linearized inverse scattering problem. We demonstrate the method on synthetic data and a marine seismic data set acquired over the Gippsland Basin near Australia. The technique is shown to reduce noise and processing artifacts while preserving discontinuities. It is likely to be particularly useful in cases where the acquired date is incomplete.

关键词： seismic image reconstruction wavelet migration

来源：评论

学校读者我要写书评

暂无评论

Numerical observer evaluation of 3D statistical PET reconstruction method with system response modeling

Numerical observer evaluation of 3D statistical PET reconstr...

引用

Nuclear Science Symposium/Medical Imaging conference

作者： Panin, v. Y. Chen, M. Casey, M. E. Siemens Med Solut Mol Imaging Knoxville TN 37932 USA

ISBN: (纸本)0780392213

Previously we have developed a 3D statistical method, which incorporates point spread function in the system matrix. Comparing to our standard 3D reconstruction algorithm with simple line integral model, this method resulted in improved resolution and noise behavior of phantom images. reconstruction of clinical data is usually performed from rebinned projection data, resulting in downsampled patient image. Efficient algorithm implementation allows reconstruction of patient data from rebinned data in time close to clinically acceptable. Then numerical observer study to evaluate algorithms performance is feasible. We use channelized Hotelling observer to establish hot spot delectability in noisy images for each method. Patient-derived phantom was used in computer simulations when a few known location tumors of various size and contrasts were added to patient image. Number of iterations and postsmoothing amount, optimal for hot spot detectability, were also investigated.

关键词： image reconstruction

来源：评论

学校读者我要写书评

暂无评论

A problem of emphasizing features of a surface roughness by means the Discrete Wavelet Transform

引用

JOURNAL OF MATERIALS PROCESSING TECHNOLOGY 2005年 164卷 1410-1415页

作者： Niola, v Nasti, G Quaremba, G Univ Naples Federico II Dept Mech Engn Energet Naples Italy

When we are interested to the detection of the roughness features by means of the 3D reconstruction, based on photometric stereo techniques, an important problem is the elimination of the brightness variation due to different light conditions which can alter the response. This paper will concentrate on presenting results of a new method for eliminating this problem. Every pixel of a picture gives only one number: the brightness of the corresponding point on the object, whereas the surface orientation is described by a normal vector that has two degrees of freedom. The level of brightness depends on many factors as well as the homogeneity of reflection properties of the material or its physical continuity and the surface smoothness or roughness. In this work we will show how the application of the Discrete Wavelet Transform (DWT) to the processing of some images, captured on different light conditions, permits to solve the problem of emphasizing roughness features of a metallic surface. Wavelet transforms can model irregular data patterns such as sharp changes, better than the Fourier transforms and standard statistical procedures (e.g., parametric and non-parametric regressions) and provide a multiresolution approximation to the data. Here we propose, also, a non-parametric method, based on the wavelet theory, for the estimation of the threshold level of a gray levels distribution, obtained from the intensity image matrix. (c) 2005 Elsevier B.v. All rights reserved.

关键词： image processing surface roughness wavelet transform optimum threshold

来源：评论

学校读者我要写书评

暂无评论

Garment motion capture using color-coded patterns

引用

COMPUTER GRAPHICS FORUM 2005年第3期24卷 439-447页

作者： Scholz, v Stich, T Keckeisen, M Wacker, M Magnor, M MPI Informat Saarbrucken Germany Univ Tubingen GRIS WSI D-72074 Tubingen Germany

In this paper we present an image-based algorithm for surface reconstruction of moving garment from multiple calibrated video cameras. Using a color-coded cloth texture, we reliably match circular features between different camera views. As surface model we use air a priori known triangle mesh. By identifying the mesh vertices with texture elements we obtain a consistent parameterization of the surface over time without further processing. Missing data points resulting from self-shadowing are plausibly interpolated by minimizing a thin-plate functional. The deforming geometry can be used for different graphics applications, e.g. for realistic retexturing. We show results for real garments demonstrating the accuracy of the recovered flexible shape.

关键词： Computer algorithms image processing Computer graphics Surfaces (Geometry) Camcorders

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：