Home Page of Jozsef Vass

Jozsef Vass' Home Page

Contact Information

Jozsef Vass
201 Engineering Building West
Department of Computer Engineering and Computer Science
University of Missouri-Columbia
Columbia, MO 65211
USA
Tel: (573) 884-6049 (office), (573) 882-6265 (lab)
Fax: (573) 882-8318
E-mail: vass@cecs.missouri.edu

Education

    Ph.D., Computer Engineering and Computer Science
        University of Missouri-Columbia, (expected)
        GPA: 4.0/4.0
        Thesis: Novel Compression Strategies in Multimedia Communications over Wireless and Wireline Networks

    M.Sc., Electrical and Computer Engineering
       University of Missouri-Columbia, Dec. 1996
        GPA: 4.0/4.0
        Thesis: Toll Quality Low Bit Rate Speech Coding and Morpho-Subband Image Coding

     Dipl. in Electrical Engineering
       Technical University of Budapest, June, 1995
        GPA: 4.63/5.0
        Thesis: Robustness of Feature Extracted Parameters in Speech Processing (in Hungarian)

Completed Courses

ECE 309 - Robotic Control and Intelligence
ECE 405 - Object-Oriented Design
ECE 365 - Introduction to Digital Image Processing
CS 365 - Database Management Systems I
ECE 477 - Coding Theory I
ECE 478 - Coding Theory II
CS 353 - Unix Operating System
ECE 479 - Computer Vision
CS 380 - Computer Networks I
CS 480 - Computer Networks II
CECS 310 - Computer Graphics I
CECS 461 - Computer Graphics II
ECE 465 - Pattern Recognition
CECS 471 - Neural Network Based Computing Systems
EE 401 - Digital Video Processing
CECS 301 - Science and Technology of World Wide Web
CECS 438 - Database Management Systems II
CECS 482 - Computer Network Modeling
CECS 401 - Multimedia Communications

Research Projects

I have been participated in several very interesting research projects:

3-D Graphics Compression. Applying wavelet decomposition to a triangular mesh is a significant challenge. After wavelet decomposition, wavelet coefficients will be transmitted in order of importance.

Landcover and Landuse Automatic Classification. Currently, Landcover and Landuse classification is semi-automatically carried out by MoRAP for the state of Missouri. We are developing automatic algorithms that can significantly speed up this process. Our research directions include Bayesian classification with learning combined with Gaussian mixture density modeling.

Video Communications over Wireless and Wireline Networks. For wireless case, we have developed a proxy-based system, where the video is adapted to the hardware capabilities and network resources of individual mobile hosts. For efficient video transmission, we our three-dimensional significance-linked connected component analysis (3D-SLCCA). Error resilience is ensured by our channel coding technique. For wireline case, we are studying 3D-SLCCA transmission over ATM networks.

J. Vass, S. Zhuang, J. Yao, and X. Zhuang, "Efficient mobile video access in wireless environments," IEEE Wireless Communications and Networking Conference, New Orleans, LA, Sep. 21-24, 1999.
J. Vass, S. Zhuang, J. Yao, and X. Zhuang, "Mobile video communications in wireless environments," IEEE International Workshop on Multimedia Signal Processing, Copenhagen, Denmark, Sep. 13-15, 1999.

Channel Coding Robust significance-linked connected component analysis is developed by integrating our SLCCA image coding scheme with multilayer error protection strategy that includes synchronization, unequal error protection, retransmission, and error concealment.

Vass and X. Zhuang, "Robust significance-linked connected component analysis for low complexity progressive image transmission over noisy channels," in Proceedings of IEEE International Conference on Image Processing, Kobe, Japan, Oct. 25-28, 1999.

Wavelet-based Video Compression. Two algorithms were developed for video communications, video significance-linked connected component analysis (VSLCCA) and three-dimensional significance-linked connected component analysis (3D-SLCCA). In VSLCCA, fine-tuned motion estimation and exhaustive overlapped block motion compensation ensures both blocking-effect-free error frames and small prediction error thus wavelet transform can be efficiently applied. Significant wavelet coefficients are represented by SLCCA algorithm. VSLCCA provides superior performance to H.263. VSLCCA was also implemented as a JAVA applet and a standalone application using Motif. (More information.) In 3D-SLCCA both the wavelet transformation and SLCCA data organization and representation strategy is extended to 3-D. In addition to high coding efficiency, 3D-SLCCA provides scalability, low computational complexity, and error resilience. 3D-SLCCA outperforms 3D-SPIHT.

J. Vass, B.-B. Chai, K. Palaniappan, and X. Zhuang, " Significance-linked connected component analysis for very low bit rate wavelet video coding," IEEE Transactions on Circuits and Systems for Video Technology, vol. 9, no. 4, pp. 630-647, June 1999.
J. Vass and X. Zhuang, "Efficient three-dimensional wavelet codecs for networked video communications," in Proceedings of IEEE International Conference on Image Processing, Kobe, Japan, Oct. 25-28, 1999.
J. Vass, B.-B. Chai, and X. Zhuang, "3DSLCCA - A highly scalable very low bit rate software-only wavelet video codec," in Proceedings of IEEE Workshop on Multimedia Signal Processing, Los Angeles, CA, Dec. 7-9, 1998.
J. Vass, B.-B. Chai, and X. Zhuang, "Significance-linked wavelet video coder," in Proceedings of IEEE International Conference on Acoustics Speech and Signal Processing, Seattle, WA, May 12-15, 1998.

Wavelet-based Image Compression. In the MCVL, we have developed a high performance image coding algorithm termed significance-linked connected component analysis (SLCCA). SLCCA outperforms Shapiro's embedded zerotree wavelet (EZW), Servetto et al. 's morphological representation of wavelet data (MRWD) and Said and Pearlman's set partitioning in hierarchical trees (SPIHT) as well. It is among the best wavelet coding algorithms publish in the literature. (More information)

B.-B. Chai, J. Vass, and X. Zhuang, "Significance-linked connected component analysis for wavelet image coding," IEEE Transactions on Image Processing, vol. 8, no. 6, pp. 774-784, June 1999.
B.-B. Chai, J. Vass, and X. Zhuang, "Statistically Adaptive Wavelet Image Coding," Visual Information Representation, Communication, and Image Processing, ed. C.-W. Cheng and Y.-Q. Zhang, Marcel Dekker Inc., 1999.
B.-B. Chai, J. Vass, and X. Zhuang, "Significance-linked connected component analysis for low bit rate image coding," in Proceedings of IEEE International Conference on Image Processing, Santa Barbara, CA, Oct. 26-29, 1997, pp. 637-640.
B.-B. Chai, J. Vass, and X. Zhuang, "A novel data representation strategy for wavelet image compression," in Proceedings of IEEE Workshop on Nonlinear Signal and Image Processing, Mackinac Island, MI, Sep. 7-11 1997.
B.-B. Chai, J. Vass, and X. Zhuang, "Significance-link connected component analysis for high performance low bit rate wavelet coding," in Proceedings of IEEE 1st Workshop on Multimedia Signal Processing, Princeton, NJ, Jun. 23-25, 1997, pp. 145-150.
B.-B. Chai, J. Vass, and X. Zhuang, "Highly efficient coded based on significance-linked connected component analysis of wavelet coefficients," in Proceedings of SPIE AeroSense'97, Orlando, FL, Apr. 20-25, 1997.

Image Database Retrieval. By using a unified image compression algorithm for storing images, indexing, and retrieval, the database management functionalities may be significantly reduced. In this research, we have chosen SLCCA as a the underlying compression algorithm, and features used for indexing are directly extracted from the SLCCA bitstream. The main research directions include 1) progressive image transmission, 2) interactive search refinement, and 2) dynamic scalable features. (More information)

J. Vass, J. Yao, A. Joshi, K. Palaniappan, and X. Zhuang, "Interactive image retrieval over the Internet," in Proceedings of Workshop on Multimedia Networking, West Lafayette, IN, Oct. 20-23, 1998.
J. Vass, J. Yao, and X. Zhuang, " An interactive image database system," in Proceedings of International Workshop on Very Low Bitrate Video Coding, Urbana, IL, Oct. 8-9, 1998.

Object-based Video Coding. The emerging MPEG-4 standard composes the scene of meaningful audio-visual objects. In the case of natural sequences, the main problem is image segmentation. We attack this problem by composing temporal and spatial segmentation known as spatio-temporal segmentation.

J. Vass, K. Palaniappan, X. Zhuang, " Automatic spatio-temporal video sequence segmentation," in Proceedings of IEEE International Conference on Image Processing, Chicago, IL, Oct. 4-7, 1998.

Nonlinear Subband Decomposition. In the MCVL, we have developed a low bit rate Morpho-Subband Image Coding Scheme. The developed algorithm outperformed Egger et al. 's adaptive subband decomposition (ASD) (O. Egger, W. Li, and M. Kunt, "High compression image coding using an adaptive morphological subband decomposition," Proc. IEEE, vol. 83, no. 2, pp. 272-287, Feb. 1995) by 2.71 dB for the Lena image at 0.16 bits-per-pixel.

X. Zhuang, J. Vass, and B.-B. Chai, " Low bit rate morpho-subband coding," in Proceedings of SPIE Visual Communications and Image Processing, vol. 3024, San Jose, CA, Feb. 1997, pp. 1057-1066.

Speech Coding. Since my focus in Hungary was speech processing my first project was speech coding. I have developed a high performance Linear Predictive Coding (LPC) quantization scheme that was applied to CELP FS1016 speech coder and superior results were obtained when compared to the original quantizer.

J. Vass, Y. Zhao, and X. Zhuang, " Adaptive forward-backward quantizer for low bit rate high quality speech coding, " IEEE Transactions on Speech and Audio Processing, vol. 5, no. 6, pp. 552-557, Nov. 1997.
Z. Yang, J. Vass, Y. Zhao, and X. Zhuang, " A novel variable rate LPC quantizer for high performance speech coder, " in Proceedings of IEEE Workshop on Nonlinear Signal and Image Processing, Mackinac Island, MI, Sep. 7-11 1997
Z. Yang, J. Vass, Y. Zhao, and X. Zhuang, " High performance CELP coder utilizing a novel adaptive forward-backward LPC quantization," in Proceedings of IEEE 1st Workshop on Multimedia Signal Processing, Princeton, NJ, Jun. 23-25, 1997, pp. 131-136.

Professional Activities

Reviewer for IEEE Transactions on Circuits and Systems for Video Technology

Reviewer for IEEE Speech and Audio Processing

Reviewer for IEEE Systems, Man, and Cybernetics

Reviewer for IEEE Signal Processing

Reviewer for Image Communications

Reviewer for International Journal of Adaptive Control & Signal Processing

Reviewer for Pattern Recognition Letters

Reviewer for ACM WoWMoM'99, MobiCom'98

System Administration

Besides my research, I am also the System Administrator of the Multimedia Communications and Visualization Laboratory. I have set up and manage 15 SGI workstations (1 Onyx2, 4 Octanes, 8 O₂s, and 2 Indigo²s). This work includes both hardware and software support, replacing defected hardware, installing patches, and licensing softwares. In addition I am also the Webmaster of the MCVL.

Publications

List of publications

CECS Multimedia Visualization and Communications Laboratory