Shape Modeling Laboratory

/ Daming Wei / Professor
/ Alexander G. Belyaev / Associate Professor
/ Jens Herder / Assistant Professor

In AY 2000, the research in the shape modeling laboratory was focused on the following directions:

• Biomedical modeling and computer simulation
• Geometric modeling and processing
• Medical application of computer and information technology

The development of a homecare service support system is another project of Prof. Wei, funded by the university competitive budget (R-17: Research and Development of Homecare Service Support System). Through the mobile Internet, the system is aimed at real-time data sharing, real-time service management, and e-service for the customers. With a mobile PC or a personal digital assistant (PDA) that rungs a web browser, the homecare service is capable of real time communicate with a server at a medical center. This project has been selected an intermediate testing project in AY 2001 by the Regional Science Program, and will be funded by Japan Science and Technology Corporation (JST). This project is expected to make a direct contribution to the domestic society.

Prof. Wei has applied a Japanese patent regarding to an invention that proposes a lead method and a processing means to enable the 12-lead electrocardiogram (ECG) monitoring with four ECG leads from the standard lead system. With this method, four leads of I, II, V1 and V6 in the M-L lead system are used in recording the ECG signals. Other four leads of V2 through V5 are derived from the input signals using the least squares method based on the Frank torso model. This method makes it possible to monitor the 12-lead ECG during ambulatory and long-term bedside monitoring in hospital environment, and for telemonitoring in homecare. This invention is expected to be a basic technology for the next-generation clinical monitors.

Prof. Belyaev has conduced fruitful results in his study on geometric modeling that includes:

• developing new methods for accurate polygonization of isosurfaces with sharp features;
• developing an image processing approach to stable detection of perceptually salient curvature extrema on triangulated surfaces;
• discovering and studying new methods for shape and image denoising coupled with feature enhancement and mesh regularization;
• developing new approaches for shape simplification with simultaneous preservation of perceptually salient shape features.

Several multipurpose geometric processing toolkits were developed. They are available on WWW at http://www.u-aizu.ac.jp/$\sim$belyaev/soft/soft.html. Some toolkits were demonstrated during the Industry-University Cooperation Forum held at the University of Aizu in December 2000 and at the University of Aizu Open Campus 2000 event in October 2000.

Refereed Journal Papers

1. Ohtake, Yu. and Belyaev, A. G., Mesh Optimization for Polygonized Isosurfaces. Computer Graphics Forum (Eurographics 2001 issue), Vol. 20, No. 3, 2001.

   In this paper, we propose a method for improvement of isosurface polygonizations. Given an initial polygonization of an isosurface, we introduce a mesh evolution process initialized by the polygonization. The evolving mesh converges quickly to its limit mesh which provides with a high quality approximation of the isosurface even if the isosurface has sharp features, boundary, complex topology. To analyze how close the evolving mesh approaches its destined isosurface, we introduce error estimators measuring the deviations of the mesh vertices from the isosurface and mesh normals from the isosurface normals. A new technique for mesh editing with isosurfaces is also proposed. In particular, it can be used for creating carving effects.

2. Watanabe, K. and Belyaev, A. G., Detection of Salient Curvature Features on Polygonal Surfaces. Computer Graphics Forum (Eurographics 2001 issue), vol. 20, No. 3, 2001.

   We develop an approach for stable detection of perceptually salient curvature features on surfaces approximated by dense triangle meshes. The approach explores an ``area degenerating'' effect of the focal surface near its singularities and combines together a new approximations of the mean and Gaussian curvatures, nonlinear averaging of curvature maps, histogram-based curvature extrema filtering, and an image processing skeletonization procedure adapted for triangular meshes. Finally we use perceptually significant curvature extrema triangles to enhance the Garland-Heckbert mesh decimation method.

3. Ohtake, Yu. and Belyaev, A. G., Automatic Detection of Geodesic Ridges and Ravines on Polygonal Surfaces. The Journal of Three Dimensional Images, vol. 15, No. 1, pp. 127-132, March, 2001.

   A method for detection of salient ridges and ravines on surfaces approximated by dense triangle meshes is proposed. The method combines together detection of mesh creases by local differential geometry operators, a mesh simplification procedure preserving main surface creases, and detection of the main surface creases on the original mesh by solving weighted length minimization problems. Presented results demonstrate robustness of the developed approach.

4. Hisada, M. and Belyaev, A. G., k-Nearest-Neighbors Graph for Fast and Robust Connection of Large 3D Point Datasets. The Journal of Three Dimensional Images, vol. 14, No. 1, pp. 136-139, December, 2000.

   Many 3D mesh generation algorithms require constructing a tree spanning a point dataset approximating the surface of a scanned object as a preprocessing step. Such a tree must be constructed quickly and its edges must connect close surface points. In this paper, we propose to use the minimal spanning tree of the k-nearest-neighbors graph for fast and geometrically appropriate spanning a 3D point dataset approximating the surface of a scanned object and demonstrate advantages of our approach. Our study also reveals several new interesting properties of the k-nearest-neighbors graph.

5. Ohtake, Yu., Belyaev, A. G. and Bogaevski, I. A., Mesh Regularization and Adaptive Smoothing. Computer-Aided Design, vol. 20, No. 3, 2001.

   The paper presents a set of mesh smoothing tools developed to increase mesh regularity, reduce oversmoothing, and enhance crease lines. Mesh smoothing with simultaneous increasing mesh regularity and reducing oversmoothing is achieved by combining together the Laplacian flow and a mesh evolution by a function of the mean curvature. To enhance salient ridge and ravine structures we use a coupled nonlinear diffusion of the mesh normals and vertices.

Refereed Proceeding Papers

1. Ritsuko Kaneko, Daming Wei, Kazuyuki Saito, and Takeshi Tsutsumi. Analysis of Minute Potentials Inside the QRS complex Using Wavelet. Proceedings of 14th Conference of the Japan Society of Medica Electronics and Biological Engineering, May 2000. pp. 495, Japan Society of Medica Electronics and Biological Engineering.

2. Atsushi Kara, Daming Wei, Osamu Koga and Kyoji Nagao., A framework of Internet-based telecare system for the bedriddens. Proceedings of 14th Conference of the Japan Society of Medica Electronics and Biological Engineering, May 2000. pp. 424, Japan Society of Medica Electronics and Biological Engineering,

3. Ritsuko Kaneko, Daming Wei, Kazuyuki Saito and Takeshi Tsutsumi., Wavelet Analysis of Minute Potentials Inside the QRS complex Using Simulated Electrocardiograms of Computer Heart Model. Proceedings of IEEE APBME 2000, pp. 127-128, IEEE, September 2000.

4. Atsushi Kara, Osamu Koga and Daming Wei., Detecting Periodic Respiratory Motion from Real-time Video Images in Telecare Monitoring. Proceedings of IEEE APBME 2000, pp. 324-325, IEEE, September 2000.

5. Song Peng, Zuxiang Fang and Daming Wei., EEG Data Compression Based on Modified LADT Algorithm. Proceedings of IEEE APBME 2000, pp. 783-784, IEEE, September 2000.

6. Daming Wei, Akashi, Nankei, Kojima, Nakayama and Sakai., Derived 12-lead ECG and its Application to ambulatory monitoring. Proceedings 28th Conference of Japan Association for Acute Medicine, pp. 586, Japan Association for Acute Medicine, October 2000.

7. Daming Wei., Analysis of electric phenomena of the heart: the development of Cardiomaster of Windows eddition. Proceedings of the 14th Autumn Conference of the Japan Society of Medical and Electronics and Biological Engineering, pp. 70, Japan Society of Medical Electronics and Biological Engineering, October 2000.

8. Ohtake, Yu., Belyaev, A. G. and Bogaevski, I. A., Polyhedral Surface Smoothing with Simultaneous Mesh Regularization. Geometric Modeling and Processing 2000, pp. 229-237, IEEE Computer Society, IEEE Computer Society Press, Los Alamitos, California, April 2000.

9. Belyaev, A. G. and Ohtake, Yu., An image processing approach to detection of ridges and ravines on polygonal surfaces. Eurographics 2000. Short Presentations, pp. 19-28, Eurographics, August 2000.

10. Belyaev, A. G., Ohtake, Yu. and Abe, K., Detection of ridges and ravines on range images and triangular meshes. Vision Geometry IX, SPIE 4117, pp. 146-154, SPIE, July-August 2000.

11. Yoshizawa, S. and Belyaev, A. G., Visualization and Study of Dynamic 2D Shapes via Curvature. Multimedia Modeling: Modeling Multimedia Information and Systems (MMM 2000), pp. 469-489, World Scientific, November 2000.

12. Ohtake, Yu. and Belyaev, A. G., Nonlinear Diffusion of Normals for Stable Detection of Ridges and Ravines on Range Images and Polygonal Models. Proceedings of MVA2000, IAPR Workshop on Machine Vision Applications, pp. 497-500, IAPR MVA Organizing Committee, November 2000.

13. Watanabe, K. and Belyaev, A. G., Detection of Curvature Extrema on Polygonal Surfaces. Proceeding of the Third International Conference on Human and Computer (HC-2000), pp. 11-14, The University of Aizu, September 2000.

14. Ohtake, Yu. and Belyaev, A. G., Detection of Geodesic Ridges and Ravines on Polygonal Surfaces. Proceeding of the Third International Conference on Human and Computer (HC-2000), pp. 5-10, The University of Aizu, September 2000.

15. Ohtake, Yu., Belyaev, A. G. and Pasko, A., Dynamic Meshes for Accurate Polygonization of Implicit Surfaces with Sharp Features. International Conference on Shape Modeling and Applications, pp. 74-81, IEEE Computer Society, Los Alamitos, California, May 2001.

16. Belyaev, A. G. and Yoshizawa, S., On Evolute Cusps and Skeleton Bifurcations. International Conference on Shape Modeling and Applications, pp. 134-141, IEEE Computer Society, IEEE Computer Society Press, Los Alamitos, California, May 2001.

17. Belyaev, A. G. and Ohtake, Yu., Nonlinear Diffusion of Normals for Crease Enhancement. Vision Geometry X, SPIE 4476, July-August 2001. SPIE,

18. Yutaka Ohtake, Masahiro Horikawa, and Alexander Belyaev., Adaptive Smoothing Tangential Direction Fields on Polygonal Surfaces. Pacific Graphics 2001, IEEE Computer Society, IEEE Computer Society Press, Los Alamitos, California, October 2001.

19. Masayuki Hisada, Alexander G. Belyaev and Tosiyasu L. Kunii., 3D Voronoi-based Skeleton and Associated Curvature Features. Pacific Graphics 2001, IEEE Computer Society, IEEE Computer Society Press, Los Alamitos, California, October 2001.

Academic Activities

1. Daming Wei., Theme Chair, IEEE APBME 2000.

Others

1. Kouji Hinai., Remote Database Access Using Java. The University of Aizu, 2000, Thesis Advisor: Daming Wei.

2. Tsuyoshi Nimonjiya., Constructing Internet Teleconference System with Java. The University of Aizu, 2000, Thesis Advisor: Daming Wei.

3. Yoshikazu Ogawa., WEB Page Construction for Cardiologic Consulting and Telecare Service. The University of Aizu, 2000, Thesis Advisor: Daming Wei.

4. Kousuke Ooshima., Constructing 3D human graphics using 2D CT images. The University of Aizu, 2000, Thesis Advisor: Daming Wei.

5. Wataru Yamanobe., Feature Extraction of Crude Drug Components Using Image Analysis. The University of Aizu, 2000, Thesis Advisor: Daming Wei.

6. Takashi Kohagura., Data acquisition system with 3D digitizer. The University of Aizu, 2000, Thesis Advisor: Daming Wei.