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CG AROUND THE WORLD

Vol.34 No.1 February 2000
ACM SIGGRAPH


Computer Graphics in Hong Kong



Zhigeng Pan
The Hong Kong Polytechnic University

Pheng-ann Heng
The Chinese University of Hong Kong

Rynson W.H. Lau
City University of Hong Kong

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Introduction

Computer graphics has evolved to become an important discipline in both academia and industry, and an enabling technology for a broad variety of applications such as engineering (CAD, CAE and CAM), GIS, publishing and office applications. It can no longer be regarded as a confined discipline devoted solely to graphics standards or traditional techniques of 3D representations and rendering. The influence of computer graphics can be felt in almost all of today’s key industrial areas, wherever computers are employed.

Computer graphics has been a subject of interest in Hong Kong in recent years. Overviews of activities in China were presented in [18, 19] and in a special journal on computer graphics [20]. However, computer graphics activities in Hong Kong were not included in these materials, since all the papers mentioned above were published before July 1, 1997, when Hong Kong returned to China. Therefore, we present this article as a supplementary part to the two overviews, and try to give people an overall picture of computer graphics activities in China.

Computer Graphics in Academia

Education and Training Activities

The field of computer graphics underwent tremendous growth in academia in Hong Kong during the 1990s. More traditional disciplines, such as computer vision and computational geometry, were previously established, and the computer graphics activities complement them well. The universities have recruited young faculties specializing in computer graphics, most notably in the fields of rendering, geometric modeling, scientific visualization and virtual reality. As a result, new courses and academic programs at both undergraduate and graduate levels have been developed to educate students in these disciplines. Students can also pursue projects specializing in various aspects of computer graphics.

Computer graphics related courses provided in the universities include Introduction to Computer Graphics, Advanced Computer Graphics, Internet-based Computer Graphics, Computer-Aided Geometric Design, Advanced Topics in Virtual Reality, Visualization, 2D and 3D Animation, Human-Computer Interface and Advanced Computer-Aided Design.

Some training centers provide practical computer graphics courses on the usage of graphics software such as Photoshop, Adobe Illustrator, 3D Studio Max, Pagemaker, CorelDraw, AutoCAD R14 and Macromedia graphics packages. For example, a professional training center called "Center for Digital Media Technology" was co-established by City University of Hong Kong and Menfond Electronic Art Ltd. to train potential professional animators.

Research Activities

Universities in Hong Kong have research programs in computer graphics, covering most of the branches within the area. It is impossible to list all research activities in computer graphics in this short column - so we instead give a brief overview of some important research in some of the particularly active fields, such as visualization and virtual reality. Readers may refer to the homepages of the computer graphics research groups for detailed information.

Figure 1
Figure 1: Multi-resolution isosurface extraction.

Visualization

Researchers in The Chinese University of Hong Kong developed interactive visualization tools for rapid noninvasive cardiac assessment jointly with researchers from the School of Medicine at Johns Hopkins University [13]. These tools use 3D-texture volume rendering, both alone and in combination with an extracted surface for cardiac strain visualization, clipped to polyhedral or curvilinear volumes under easy user control. Effective visualization techniques and recent advances in MR physics make it possible that a single assessment session with a single imaging method may provide a comprehensive cardiac workup. Poston et al [15] proposed an isosurface extraction algorithm – Adaptive Skeleton Climbing – which can directly generate multi-resolution isosurfaces from volume data. It generates low resolutions, with 4 to 25 times fewer triangles than that generated by the Marching Cubes algorithm, in comparable running time. Unlike previous adaptive marching cube algorithms, the algorithm does not suffer from the gap-filling problem. Figure 1 shows an example.

In order to explore and analyze very large medical databases, researchers in The Chinese University of Hong Kong are currently developing an intelligent system for interactive medical data mining and visualization. Such a data mining system would enable physicians or researchers to extract more clinically useful information from multiple datasets in order to achieve more accurate diagnosis or help make a better surgical decision together with interactive medical visualization tools for visual comparison and surgical simulation. The system would be an ideal tool for training and research in diagnostic imaging.

In addition, researchers at The Computer Graphics Group, the University of Hong Kong [3] are engaged in a joint project utilizing visualization techniques to assist with surgery planning, in cooperation with the Department of Orthopaedic Surgery and Traumatology at Queen Mary Hospital.

Figure 2
Figure 2: Rendering of illumination-controllable panorama.

Virtual Reality (VR)

As a new branch of computer graphics, VR has attracted a lot of attention in recent years. Research work in this direction in Hong Kong covers various VR topics, including real-time rendering, image-based rendering, VR applications and distributed VR.

Real-time display of arbitrarily complex scenes is a hard problem in traditional geometry-based computer graphics. One solution is geometric simplification. Lau et al presented an efficient multi-resolution technique for object modeling [10], which was recently refined to take into account the dynamically changing view and animation factors. The algorithm aims to improve the rendering performance in time-critical applications.

Image-based modeling and rendering offers an alternative approach. Its rendering time is independent of scene complexity. To control the illumination, Wong et al treated each image pixel as an ordinary surface element and measures its apparent BRDF from reference images. By manipulating these apparent pixel BRDFs, they were able to rerender (change the illumination of the scene in an image) without any geometry information [30]. Figure 2 is an example. Bao et al presented a progressive view morphing method and wavelet-based image mosaics using edge-preserving visual perception modeling. The latter algorithm considers how humans perceive images and uses this information to produce impressive image-based rendering results [2].

VR application areas include education, training, engineering (such as virtual assembling and manufacturing [22] and architecture walkthrough [26]) and medicine. One example is the virtual bronchoscopy system developed by the VR, Visualization and Imaging Research Center, The Chinese University of Hong Kong [28]. A major improvement over other existing medical simulation systems is the integration of advanced knowledge based tools within all aspects of the virtual environment, including automatic data segmentation, adaptive volume rendering, multi-resolution modeling, intelligent user interface for data navigation and surgical simulation of the bronchoscopic surgery.

The Computer Graphics Group at The University of Hong Kong developed a walkthrough system for indoor environments [3]. The system adopts several new rendering speedup techniques to achieve real-time walkthrough. A distributed VR system for the walkthrough of large virtual environments over the Internet was developed by the VR Group at City University of Hong Kong [7]. Instead of transmitting the complete geometry database to the client before the start of the walkthrough, as most systems do, this system is based on the on-demand transmission of object models to the client in the form of progressive meshes [4].

In addition, some other VR research results on visibility computation, collision detection [3], virtual-hand interfaces [25], virtual trackball-ruler interface [1], modeling of virtual objects with sound vibration properties [17] are also achieved.

Figure 3
Figure 3: An example of deforming a face model.

Modeling and Animation

Modeling and processing of geometric shape is fundamental to many disciplines, such as computer vision, CAD/CAM, medical imaging and scientific computation. In geometric modeling and CAD, some exciting research results have been achieved, including a new interpolation method for quadric surfaces and polyhedral models [21, 29], shape design and surface representations [9, 23, 24] and the parameterization of surfaces [12].

In computer animation, work has been carried out in modeling and animating human faces and limbs in the Image Computing Group of City University of Hong Kong [6]. Example applications of this technique can be found in facial surgery, lip-reading tutoring, video conferencing system and physical therapy. The researchers utilize NURBS surfaces to model human faces, and a hierarchical approach to model and animate different facial gestures and mouth movements [8]. To handle real-life objects in a real-time environment, an algorithm was developed for interactive editing and rendering of deformable objects. The main idea of this approach is to maintain both a surface model and a polygon model of each deformable surface. When the surface deforms, the polygon model is updated with some pre-computed coefficients to represent the deformed surface. Figure 3 shows an example.

Other Computer Graphics Related Activities

Some conferences related to computer graphics have been held in Hong Kong. Three conferences or workshops will be held in the year 2000:

Geometric Modeling and Processing 2000 will be held in Hong Kong on April 10-12, 2000. It is the first of a biennial international conference on solid modeling, shape representation and geometric computation. See the website.

Pacific Graphics 2000 will be held in Hong Kong on October 3-5, 2000. It is an annual international conference on computer graphics and applications. See the website.

International Workshop on Multimedia Data Storage, Retrieval, Integration and Application will be held in Hong Kong on January 13-15, 2000. See the website.

In addition to research paper publication, some images created using computer graphics techniques by Wong in The Chinese University of Hong Kong are published as SIGGRAPH technical slides (from 1996 to 1999). They are available for viewing at website.

In 1999, the School of Design of Hong Kong Polytechnic University established a global virtual design studio (GVDS) [11]. GVDS is a multi-purpose, multi-function and truly multimedia facility designed for academic research, external applied research, commercial consultancy and student use. The GVDS has two main sections: (a) a three-way projection system and a digital sound system and (b) an SGI Onyx2 graphics supercomputer and other smaller computer and video systems. The GVDS allows virtual simulations of architectural, industrial and fashion designs, enabling designers to test and evaluate prospective designs in real time, minimizing the need for costly scale models.

Computer Graphics in Industry

Concurrent with growth in academia, computer graphics and related technologies have flourished in Hong Kong over the past few years. An exhaustive list of companies active in computer graphics would be beyond the scope of this article. The main applications of computer graphics include publishing, mechanical CAD/CAM, electronic CAD/CAE, garment CAD, medical and scientific visualization, animation for video and film, training and simulation. Here we mention just a few of the more conspicuous ones in representative fields, including media production, garment and apparel and construction.

Applications in Digital Media Production

Some professional companies in Hong Kong use animation techniques for digital media production. For example, Menfond Electronic Art Ltd. [14] was established in 1990. It has evolved to be one of the biggest computer graphics production houses in Asia. In 1991, the company produced the first 30-second full computer graphics TV commercial in Hong Kong called "EPRO Paging." Since then, it has produced hundreds of TV commercials and short animations. Awards received include The New York Festival, Japan International Advertising Association Award and Hong Kong 1st IT Excellence Award. The company was the first digital production facility in South East Asia to exhibit computer animation in SIGGRAPH and IMAGINA (the largest computer graphics exhibition in Europe). Menfond has expanded its market to Japan, U.S.A. and Europe. Recently, it produced City of Fire, the first full 3D digital animated feature produced in Asia, and The Moebius Trip, a 26-episode 3D digital TV series. Besides producing animation with commercial software, Menfond also develops tools, such as Menfond Production System, Special Shaders and Facial Expression system.

Figure 4
Figure 4: 3D-like draping.

Applications in Garment and Apparel Industry

The market for specialized, cost-efficient design tools in the garment and apparel industry CAD has experienced significant growth in recent years. Prima Design System Ltd. [16] was an early pioneer of color CAD systems for the garment and apparel industry. It has one of the largest user bases in its field worldwide. In a garment industry survey organized recently by the Hong Kong Institute of Clothing, PrimaVision from Prima Design System Ltd. came out ahead by an overwhelming margin as the most popular CAD system amongst respondents in the Hong Kong garment trade. It is a powerful painting and image manipulation tool that includes state-of-the-art 3D-like draping features within 16.7 million colors, with strong support for catalogues, storyboards and layout design (see Figure 4). In addition, PrimaVision won the 1996 Hong Kong Award for Industry in Machinery and Equipment Design.

Applications in Construction Industry

The use of CAD/CAM systems in the manufacturing industry has been growing. The imports of CAD/CAM software have been steadily increasing over the last few years. In addition, some professional CAD-related products are being developed locally. For example, VHSoft [27], a CAD software company specializing in construction, has developed an intelligent construction environment that provides an integrated workflow for construction automation. It adopts a much more advanced level of integration instead of the traditional approach of data format integration. The environment is composed of the following graphic tools: VHVector (software for performing vectorization of construction drawings), VHStation (software for recognizing drawing plans and generation of bending schedules and subsummaries in a flexible format), VHDrawings (a sophisticated drawing management system custom-made for managing drawings such as architectural, structural, details and building services) and VHCAD (CAD software for creating professional 2D and 3D design).

Conclusions

Research and development in computer graphics in Hong Kong has spanned most branches in the area. We have briefly looked at various computer graphics related activities, but inevitably, given such a short article, it is impossible to give a comprehensive picture of CG in Hong Kong and cover all activities in the computer graphics field. We apologize in advance for missing any relevant papers, achievements and products of computer graphics in Hong Kong. Finally, we hope the researchers in Hong Kong will continue to make promising achievements in the field of computer graphics.

References

  1.  Baciu, G. "The Virtual Trackball-Ruler Interface," Virtual Reality: Research Development and Applications, 2(2), pp. 185-194, 1996.
  2.  Bao, P. and D. Xu. "Complex Wavelet-based Image Mosaics using Edge-preserving Visual Perception Modeling," Computers & Graphics, 23(3), pp. 309-321, 1999.
  3.  CG Group. The University of Hong Kong, website.
  4.  Chim, J., R.W.H. Lau, A. Si, H.V. Leong, D. To, M. Green and M.L. Lam. "Multi-Resolution Model Transmission in Distributed Virtual Environments," ACM VRST, pp. 25-34, Nov. 1998.
  5.  GVDS. School of Design, Hong Kong Polytechnic University, website.
  6.  Image Computing Group. City University of Hong Kong, website.
  7.  IMVR Lab. City University of Hong Kong, website.
  8.  Ip, H. and S. Chan. "Scripted-Based Facial Gesture and Speech Animation Using a NURBS Based Face Model," Computers & Graphics, 20(6), pp. 881-891, 1996.
  9.  Lam, S. "Multi-resolution Representation of Interval Surfaces Using Subdivision Wavelet Transform and Linear Programming," Computers & Graphics, 23(4), pp. 555-572, 1999.
  10.  Lau, R.W.H., M. Green, D. To and J. Wong. "Real-Time Continuous Multi-Resolution Method for Models of Arbitrary Topology," Presence, MIT Press, 7(1), pp. 22-35, 1998.
  11.  Li, F, R.W.H. Lau and M. Green. "Interactive Rendering of Deforming NURBS Surfaces," Eurographics’97, 16(3), pp. 47-56, Sept. 1997.
  12.  Ma, W. and J. Kruth. "Parameterization of Randomly Measured Points for Least Squares Fitting of B-spline Curves and Surfaces," Computer Aided Design, 27(9), pp. 663-675, 1995.
  13.  Meiyappan, S., T. Poston, P.A. Heng, E. Zerhouni, E. McVeigh and M. Guttman. "Interactive Visualization for Speedy Non-invasive Cardiac Assessment," IEEE Computer, 29(1), pp. 55-62, 1996.
  14.  Menfond Electronic Art. website.
  15.  Poston, T., T.T. Wong and P.A. Heng. "Multiresolution Isosurface Extraction with Adaptive Skeleton Climbing," Computer Graphics Forum, 17(3), pp. 137-148, 1998.
  16.  Prima Design System Ltd. website.
  17.  Rossiter, D., G. Baciu and A. Horner. "An Investigation into the Modeling of Virtual Objects with Sound Vibration Properties," Virtual Reality: Research Development and Applications, Volume 1, No. (2), pp. 117-121, 1996.
  18.  Shi, J.Y. and Z.G. Pan. "China: Computer Graphics Education Available at Universities, Institutes and Training Centers," Computer Graphics 31(3), pp. 7-9, 1996.
  19.  Shi, J.Y. and Z.G. Pan. "China: Computer Graphics is Fastest Developing Computer Application," Computer Graphics, 31(2), pp. 11-14, 1996.
  20.  Shi, J.Y. and Z.G. Pan, editors. Special Issue on "Computer Graphics in China," Computers & Graphics, 21(3), 1997.
  21.  Sun, Y., W. Wang and F. Chin. "Interpolating Polyhedral Models Using Intrinsic Shape Parameters," Journal of Visualization and Computer Animation, 8, pp. 81-96, 1997.
  22.  Sun, H., X. Yuan, G. Baciu and Y. Gu. "Direct Virtual-hand Interface in Robot Assembly Programming," The Journal of Visual Languages and Computing, 10, pp. 55-68, 1999.
  23.  Tai, C. and K. Loe. "Surface Design via Deformation of Periodically Swept Surfaces," Visual Computer, 12, pp. 475-483, 1996.
  24.  Tai, C, Y. Shinagawa and T. Kunii. "A Reeb Graph-based Representation for Non-sequential Construction of Topologically Valid Shapes," Computers & Graphics, 22(2), pp. 255-268, 1998.
  25.  Tsang, K.H. and H. Sun. "An Efficient Posture Recognition Method Using Fuzzy Logic," The Journal of Virtual Reality: Research, Development and Applications, 3(2), pp. 112-119, 1998.
  26.  Tsou, J.Y. "Developing Group-based Simulated Virtual Environment for Design Education and Integration," The 8th International Conference on Systems Research, Informatics and Cybernetics, pp. 31-40, August 1996.
  27.  VHSoft Company. website.
  28.  VR. Visualization and Imaging Research Center, The Chinese University of Hong Kong.
  29.  Wang, W. and B. Joe. "Interpolation on Quadric Surfaces by Rational Quadratic Spline Curves," Computer Aided Geometric Design, 14(3), pp. 207-230, 1997.
  30.  Wong, T.T., P.A. Heng, S. Or and W. Ng. "Illumination of Image-based Objects," Journal of Visualization and Computer Animation, 9, pp. 113-127, 1998.


Zhigeng Pan is a Professor at the State Key Lab of CAD and CG at Zhejiang University in China. Currently he works as a Research Fellow in Hong Kong Polytechnic University. His research interests are multi-resolution modeling, time-critical rendering, distributed VR, intelligent virtual environment and digital watermarking.

Pheng-ann Heng is an Associate Professor and the Director of the Virtual Reality, Visualization and Imaging Research Centre at The Chinese University of Hong Kong. His research interests include virtual reality applications in medicine, scientific visualization, 3D medical imaging, user interface, rendering, modeling, interactive graphics and animation.

Rynson W.H. Lau is an Assistant Professor at the City University of Hong Kong. His research interests include multi-resolution modeling techniques, surface deformation and rendering, distributed virtual walkthrough and Web-based digital libraries.



If you would like to provide an overview of computer graphics in your country, please contact one of our Computer Graphics Around the World columnists listed on the below.

Jose Encarnação
Fraunhofer-Institut fuer Graphische
Datenverarbeitung
Wilhelminenstrasse 7
D-64283 Darmstadt
Deutschland

Tel: +49-(0)6151-155-1301
Fax: +49-(0)6151-155-4301
Alain Chesnais
Alias|Wavefront
210 King St East
Toronto, Ontario M5A 1J7
Canada

Tel: +1-416-362-8558 x8589
Fax: +1-416-369-6156

Zhigeng Pan
Department of Computing
The Hong Kong Polytechnic University
Hung Hom Kowloon, Hong Kong

Pheng-ann Heng
The Chinese University of Hong Kong
Department of Computer Science and Engineering
Shatin, N.T., Hong Kong

Rynson W.H. Lau
Department of Computer Science
City University of Hong Kong
Tat Chee Avenue, Kowloon, Hong Kong

The copyright of articles and images printed remains with the author unless otherwise indicated.