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IEEE Pacific Rim Conference on Communications, Computers and Signal Processing

作者： Lee, Myungeun Park, Soonyoung Cho, Wanhyun Kim, Soohyung Jeong, Changbu Chonnam Natl Univ Dept Comp Sci Kwangju 500757 South Korea Mokpo Natl Univ Dept Elect Engn Jeonnam 534729 South Korea Chonnam Natl Univ Dept Stat Kwangju 500757 South Korea Honam Univ Dept Internet Software Kwangju 506714 South Korea

An automatic segmentation method for medical images that uses a geometric deformable model is presented, and the segmented results are visualized with the help of a modified marching cubes algorithm. The geometric deformable model is based on evolution theory and the level set method. In particular, the level set method utilizes a new derived speed function to improve the segmentation performance. This function is defined by the linear combination of three terms, namely, the alignment term, the minimal-variance term, and the smoothing term. The alignment term makes a level set as close as possible to the boundary of an object. The mini mal-variance term best separates the interior and exterior of the contour. The smoothing term renders a segmented boundary less sensitive to noise. The use of the proposed speed function can improve the segmentation accuracy while making the boundaries of each object much smoother. Finally, it is demonstrated that tire design of the speed function plays an important role in the reliable segmentation of synthetic and computed tomography (CT) images, and the segmented results are visualized effectively with the help of a modified marching cubes algorithm.

关键词： computed tomography image evolution theory geometric deformable model image segmentation level set method marching cubes algorithm

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An Improved MC algorithm Applied in Medical Image Reconstruction

An Improved MC Algorithm Applied in Medical Image Reconstruc...

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20th Chinese Control and Decision Conference

作者： Xiao, Jun Yu, Miao Jia, Ningyu Northeastern Univ Coll Informat Sci & Engn Shenyang 110004 Peoples R China

ISBN: (纸本)9781424417339

marching cubes algorithm is a widely used surface rendering method. But MC algorithm also has its disadvantages, such as ambiguous surface and the huge quantities of the triangle patches generated. This paper improve the MC algorithm by changing traversing method into multi-line traversing method to take advantage of multi-pipeline technology. And we also resolves the ambiguity by use of asymptotic decider. Finally, we wrote a programme and ran it on a PC to test it. The experimental results show that the improved method can remove the disadvantages mentioned above and obtain a satisfying reconstructed surface.

关键词： Surface reconstruction Medical image processing marching cubes algorithm

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Converting CSG models into meshed B-Rep models using Euler operators and propagation based marching cubes

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JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING 2007年第4期29卷 337-344页

作者： Tsuzuki, Marcos de Sales G. Takase, Fabio K. Garcia, Murilo Antonio S. Martins, Thiago de Castro Univ Sao Paulo Escola Politeccn Dept Mechatron & Mech Syst Engn BR-05508900 Sao Paulo Brazil

The purpose of this work is to define a new algorithm for converting a CSG representation into a B-Rep representation. Usually this conversion is done determining the union, intersection or difference from two B-Rep represented solids. Due to the lack of explicit representation of surface boundaries, CSG models must be converted into B-Rep solid models when a description based on polygonal mesh is required. A potential solution is to convert a CSG model into a voxel based volume representation and then construct a B-Rep solid model. This method is called CSG voxelization, conceptually it is a set membership classification problem with respect to the CSG object for all sampling points in a volume space. marching cubes algorithms create a simple mesh that is, enough for visualization purposes.. However, when engineering processes are involved, a solid model is necessary. A solid ensures that all triangles in the mesh are consistently oriented and define a closed surface. It is proposed in this work an algorithm for converting CSG models into triangulated solid models through propagation based marching cubes algorithm. Three main new concepts are used in the algorithm: open boundary, B-Rep/CSG Voxelization mapping and constructive triangulation of active cells. The triangle supplied by the marching cubes algorithm need not be coherently oriented;the algorithm itself finds, the correct orientation to the supplied triangles. The proposed algorithm restricts the exploration to the space occupied by the solids boundary. Differently from normal marching cubes algorithms that explore the complete sampled space.

关键词： solid model marching cubes algorithm triangular meshes

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An interactive system for visualizing 3D human organ models

An interactive system for visualizing 3D human organ models

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Computer Aided Design and Computer Graphics, 2005. Ninth International Conference on

作者： Un-Hong Wong Hon-Cheng Wong Zesheng Tang Faculty of Information Technology Macao University of Science and Technology Avenida Wai Long Taipa Macao China

ISBN: (纸本)0769524737

Demonstrations play a major role in education process. Although many specimens are readily available, particularly in medicine and biology, demonstrations are commonly performed by showing these static specimens to medical or biological students. Interactive demonstrations can significantly impacts learning. An interactive system for visualizing 3D human organ models can fulfil this need. In this paper, we present techniques to realize such a system which can let the user select and view one or several major organ models extracted from segmented visible human dataset interactively through a simple graphical user interface. The stereoscopic views of these organ models are also achieved with this system running on a PC-based stereo-ready system. In our system, the marching cubes algorithm is used but new implementation we proposed to greatly improve both the speed and quality of surface rendering results is performed. This new implementation can generate the marching cubes cases on-the-fly within the surface extraction process of the models by considering the relationship of the vertices, borders, and surfaces of each voxel. We also describe a new method for specifying the normals for the extracted triangles without the need of physical information (such as intensity values stored in a medical computed tomography (CT) dataset) stored in the voxels. These normals will be used for lighting the extracted models later. Furthermore, a memory arrangement scheme is designed to enhance the usability of the system.

关键词： computer aided instruction data visualisation graphical user interfaces interactive systems medical image processing 3D human organ model visualization graphical user interface interactive system marching cubes algorithm medical computed tomography memor

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A novel and efficient implementation of the marching cubes algorithm

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COMPUTERIZED MEDICAL IMAGING AND GRAPHICS 2001年第4期25卷 343-352页

作者： Delibasis, KS Matsopoulos, GK Mouravliansky, NA Nikita, KS Natl Tech Univ Athens Inst Commun & Comp Syst GR-15773 Athens Greece

In this paper, a novel and efficient implementation of the marching cubes (MC) algorithm is presented for the reconstruction of anatomical structures from real three-dimensional medical data. The proposed approach is based on a generic rule, able to triangulate all 15 standard cube configurations used in the classical MC algorithm as well as additional cases presented in the literature. The proposed implementation of the MC algorithm can handle the Type A 'hole problem' which occurs when at least one cube face has an intersection point in each of its four edges. Theoretical and experimental results demonstrate the ability of the new implementation to reproduce standard MC results, resolving Type A 'hole problem'. Finally, the proposed implementation was applied to real medical date to reconstruct anatomical structures. The output of the proposed technique is in WWW compliant format. (C) 2001 Elsevier Science Ltd. All rights reserved.

关键词： 3-D reconstruction marching cubes algorithm isosurface medical imaging

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Multi-resolution surface reconstruction

Multi-resolution surface reconstruction

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International Conference on Image Processing (ICIP 2004)

作者： He, MY Xiong, BS Yu, HJ Northwestern Polytech Univ Dept Elect & Informat Engn Xian 710072 Peoples R China

ISBN: (纸本)0780385543

This paper presents a novel surface reconstruction algorithm, which can directly generate multi-resolution meshes from the unorganized cloud points. Local normal change is used to determine whether local surface is flat or rough. According to the user-specified normal change threshold, a min-max box containing all sample points is split into octree cells with different sizes. If the local surface is flat, a portion of the isosurface will be extracted in a large cell, otherwise in a small one. Thus the proposed algorithm can reduce the number of triangles in mesh compared with conventional marching cubes (MC) algorithm. The datasets of Terracotta Warrior and Horses in Qin Dynasty and the Kettle in Song Dynasty are used to verify the efficiency of our algorithm. The experimental results show that this algorithm call greatly decrease the number of triangles with the increase of the normal chan-e threshold and maintain the details of surface.

关键词： image reconstruction image resolution minimax techniques trees (mathematics) multiresolution surface reconstruction unorganized cloud point user-specified normal change threshold min-max box octree cell marching cubes algorithm

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Medical visualization based on VRML technology and its application

Medical visualization based on VRML technology and its appli...

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Conference on 3-Dimensional and Multidimensional Microscopy - Image Acquisition and Processing X

作者： Yin, M Luo, QM Lu, Q Sheng, RB Liu, YF Huazhong Univ Sci & Technol Minist Educ Key Lab Biomed Photon Wuhan 430074 Peoples R China

ISBN: (纸本)0819447641

Current high-performance computers and advanced image processing capabilities have made the application of three dimensional visualization objects in biomedical images facilitate the researches on biomedical engineering greatly. Trying to cooperate with the update technology using Internet, where 3-D data are typically stored and processed on powerful servers accessible by using TCPAP, we held the results of the isosurface be applied in medical visualization generally. So in this system we use the 3-D file format VRML2.0, which is used through the Web interface for manipulating 3-D models. In this program we implemented to generate and modify triangular isosurface meshes by marching cubes algorithm, using OpenGL and MFC techniques to render the isosurface and manipulate voxel data. This software is more adequate visualization of volumetric data. The drawbacks are that 3-D image processing on personal computers is rather slow and the set of tools for 3-D visualization is limited. However, these limitations have not affected the applicability of this platform for all the tasks needed in elementary experiments in laboratory or data preprocessed. With the help of OCT and MPE scanning image system, applying these techniques to the visualization of rabbit brain. constructing data sets of hierarchical subdivisions of the cerebral information, we can establish a virtual environment on the World Wide Web for the rabbit brain research from its gross anatomy to its tissue and cellular levels of detail. providing graphical modeling and information management of both the outer and the inner space of the rabbit brain.

关键词： 3-D visualization biomedical image marching cubes algorithm isosurface virtual reality VRML Internet rabbit brain finite elements OCT MPE

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3-D visualization of biomedical CT images based on OpenGL and VRML techniques

3-D visualization of biomedical CT images based on OpenGL an...

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International Workshop on Photonics and Imaging in Biology and Medicine

作者： Yin, M Luo, QM Xia, FH Huanzhong Univ Sci & Technol Key Lab Biomed Photon Minist Educ Wuhan Peoples R China

ISBN: (纸本)0819442607

Current high-performance computers and advanced image processing capabilities have made the application of three dimensional visualization objects in, biomedical computer tomographic (CT) images facilitate the researches on biomedical engineering greatly. Trying to cooperate with the update technology using Internet, where 3-D data are typically stored and processed on powerful servers accessible by using TCP/IP, we should hold the results of the isosurface be applied in medical visualization generally. Furthermore, this project is a future part of PACS system our lab working on. So in this system we use the 3-D file format VRML2.0, which is used through the Web interface for manipulating 3-D models. In this program we implemented to generate and modify triangular isosurface meshes by marching cubes algorithm. Then we used OpenGL and WC techniques to render the isosurface and manipulating voxel data. This software is more adequate visualization of volumetric data. The drawbacks are that 3-D image processing on personal computers is rather slow and the set of tools for 3-D visualization is limited. However, these limitations have not affected the applicability of this platform for all the tasks needed in elementary experiments in laboratory or data preprocessed.

关键词： 3-D visualization biomedical image marching cubes algorithm isosurface OpenGL VRML Internet

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High-resolution triangulation of arbitrary shaped surfaces based on coordinate curves

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Conference on 3-Dimensional Image Capture and Applications III

作者： Timsari, B Univ So Calif Inst Signal & Image Proc Los Angeles CA 90089 USA

ISBN: (纸本)0819435767

A new method is proposed for building a polyhedral mesh from a set of planar contours representing coordinate constant slices of an object. This method can be used for extracting a boundary surface from volumetric data, a typical application of which is surface reconstruction for objects imaged by Computed Tomography (CT). With a computational complexity and processing time comparable to those of the marching cubes algorithm, an alternative method for extracting iso-surfaces From CT images, this method creates a surface with half of the number of triangles required by marching cubes without sacrificing for the accuracy of the surface. This algorithm begins with identifying boundary vertices in three sets of mutually perpendicular planes through the volumetric image data. Using the neighborhood relationship between the vertices in each plane the three dimensional neighborhood structure of the surface is determined, and either 4 or 6 neighbors are assigned to each vertex. The surface is then tiled with triangles by joining each vertex to two of its immediate neighbors. We applied this method to both computer generated phantom data, and real Magnetic Resonance (MR) images of human head and compared the results with those of the marching cubes algorithm. The experiments show that the proposed method creates more regular and uniform triangulation with smaller number of triangles.

关键词： surface tessellation surface modeling polygonal approximation triangulation polyhedral mesh coordinate curves marching cubes algorithm Computed Tomography

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A comparative study of isodensity surfaces using ab initio and ASA density functions

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JOURNAL OF MOLECULAR GRAPHICS & MODELLING 1998年第4-6期16卷 190-196页

作者： Gironés, X Amat, L Carbó-Dorca, R Univ Girona Inst Computat Chem Girona 17071 Catalonia Spain

In this article, we report a visual comparison between several of the available methods for constructing electronic density functions. The density forms studied include ab initio, atomic shell approximation, and promolecular densities. A graphical comparison is made for six different molecules at different levels of density function values. The differences between the various density functions are analysed by considering a molecular quantum self-similarity measure and the required computational time for all molecules at all computation levels is considered. (C) 1999 by Elsevier Science Inc.

关键词： ab initio densities atomic shell approximation densities marching cubes algorithm promolecular densities molecular quantum similarity measures

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