Xiaolin Wu

Professor

                      NSERC-DALSA Industrial Research Chair in Digital Cinema

 

                        Department of Electrical & Computer Engineering
ITB A315
McMaster University
Hamilton, Ontario, Canada, L8G 4K1

 

phone:  905 525-9140 ext 24190

 

fax:  905 521-2922

 

email: xwu at ece.mcmaster.ca

COURSES:    Data Structures and Algorithms (2SI4)

                        Image Processing (4TN4)

                        Numerical Analysis (3SK3)

RESEARCH:

My general research activities are in visual/multimedia computing and communications. I have published numerous algorithms for computer graphics and image processing (image coding in particular), some of which are being used by practitioners, such as a fast optimal color quantizer, and a Context-based Adaptive Lossless Image Codec (CALIC) which was developed jointly with Nasir Memon as a candidate algorithm for the new JPEG lossless standard. CALIC(executable) is widely used as a benchmark in performance evaluation of lossless image codecs.

I and my students have also developed

·         The best color demosaicking technique so far in the literature: Primary-Consistent Soft-Decision (PCSD executable: pcsd.rar) color demosaicking algorithm.

·         The best image interpolation technique so far in the literature: Soft-decision Adaptive Interpolation (SAI executable: sai.rar) algorithm.

·         Model-based Adaptive Recovery of Compressive Sensing: MARX algorithm (executable: marx.rar).

I have also been active in JPEG standardization process, and proposed new techniques for context modeling and Embedded Conditional Entropy Coding of Wavelet coefficients (ECECOW). My new L-cube (Layered Low-complexity Lossless) codec was ranked the first in compression performance among seven proposals submitted to MPEG for digital cinema archival.

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Ongoing Government-funded Research Projects:

·        Network-aware Multimedia Coding and Communication (funded by NSERC)

·        High-fidelity 2D and 3D image compression (NSERC Collaborative Health Research Project)

·        Joint compression and classification of hyperspectral images (funded by Center for Research in Earth and Space Technology)

·        Real-time lossless/near-lossless coding of digital cinema contents (by NSERC-DALSA Industrial Research Chair Project and CFI)

·        Color demosaicking for digital movie cameras (funded by NSERC-DALSA Industrial Research Chair Project and CFI)

 

 

Research Positions

 

Research topics:

 

Optimization algorithms for designing codes used in communications and data compression, and for problems in digital cinema or biomedical image processing.

 

Qualifications:

 

Ph.D or equivalent in Computer Science, Electrical Engineering, or Mathematics. Strengths in discrete optimization, graph theory, and algorithms are highly valued.

 

Duration:

 

            One year and renewable.

 

Annual salary:

 

            $35,000 to $60,000, depending on qualifications and experiences. 

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Our Research Group (Multimedia Computing and Communications Laboratory)

·         Xiaohan Wang (Ph.D student)

·         Xiangjun Zhang (Ph.D student)

·         Mingkai Shao (Ph.D student)

·         Amin Behnad (M.A.Sc. student)

·         Reza Pournaghi (M.A.Sc. student)

·         Hauzhong Wang (M.A.Sc. student)

·         Jie Cao (M.A.Sc. student)

·         Heng Wang (M.A.Sc. student)

·         Yong Zhao (M.A.Sc. student)

·         Cindy Kwan (M.A.Sc. student, now with Microsoft)

·         Nima Sarshar (Ph.D student, now with Univ. of Regina)

·         Marko Slyz (postdoctoral fellow)

·         Zhe Wang (Ph.D student, now with Google)

·         Lei Zhang (postdoctoral fellow, now with HK Poly. Tech. Univ.)

·         Ning Zhang (research associate, now with IMAX Corp.)

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Selected Publications:

Joint source-channel and network coding

  • X. Wu, B. Ma and N. Sarshar, “Rainbow network problems and multiple description coding”, IEEE Trans. on Information Theory, vol. 54, no. 10, pp. 4565-4574, Oct. 2008.
  • X. Wu, X. Wang, and Z. Wang, "Resource-scalable joint source-channel MAP and MMSE estimation of multiple descriptions", IEEE Trans. on Signal Processing, vol. 57, no. 1, pp. 279-288, Jan. 2009.
  • S. Dumitrescu and X. Wu, “On the complexity of joint source-channel decoding of Markov sequences over memoryless channels”, IEEE Trans. on Communications, vol. 56, no. 6, pp. 877-885, June 2008.
  • S. Dumitrescu, X. Wu, and Z. Wang, “Efficient algorithms for optimal uneven protection of single and multiple scalable code streams against packet erasures”, IEEE Trans. on Multimedia, vol. 9, no. 7, pp. 1466-1474, Nov. 2007.
  • X. Wu, S. Dumitrescu, and Z. Wang, “Monotonicity-based fast algorithm for MAP estimation of Markov sequences over noisy channels”, IEEE Trans. on Information Theory, vol.50, no.7, pp.1539-1544, July 2004.
  • Z. Wang and X. Wu, “Length-constrained MAP decoding of variable length encoded Markov sequences”, IEEE Trans. on Communications, vol.54, no.7, pp.1259-1266, July, 2006.
  • S. Dumitrescu, X. Wu, and Z. Wang, ”Globally optimal uneven error protected packetization of scalable code streams”, IEEE Trans. on Multimedia, vol. 6, no. 2, pp. 230-239, Apr. 2004.
  • N. Sarshar and X. Wu, “A practical approach to joint network-source coding”, Proc. of DCC 2006 (dcc06.pdf).
  • X. Huang and X. Wu, “Optimal index assignment for multiple description lattice vector quantization”, Proc. of DCC 2006 (IAMDLVQ.pdf).
  • X. Wu, X. Wang, and J. Wang, “Joint source-channel decoding of multiple description quantized Markov sequences”, Proc. of DCC 2006 (MDQMAP.pdf).
  • B. Ma and X. Wu, “Maximum network flow of multiple description codes”, Proc. of NetCod 2005, Apr. 2005.
  • N. Sarshar and X. Wu, “Statistical mechanics of optimal networked source coding”, Proc. of NetCod 2005, Apr. 2005.
  • X. Wu, S. Cheng and Z. Xiong, ``On packetization of embedded multimedia bitstreams'', IEEE Trans. on Multimedia, 2001, vol. 3, pp. 132-140, 2001.

 

Signal quantization and source coding

 

  • S. Dumitrescu and X. Wu, “Lagrangian optimization of two-description scalar quantizers”, IEEE Trans. on Information Theory, vol. 53, no. 11,  pp. 3990-4012, Nov. 2007.
  • M. Xue, X. Wu, P. Franti, “Context quantization by kernel Fisher discriminant”, IEEE Trans. on Image Processing, vol. 15, no. 1, pp. 169-177, Jan. 2006.
  • S. Dumitrescu and X. Wu, “Optimal two-description scalar quantizer design”, Algorithmica, vol. 41, no. 4, pp. 269-287, Feb. 2005.
  • S. Dumitrescu and X. Wu, “Algorithms for optimal multi-resolution quantization", Journal of Algorithms, vol. 50, no. 1, pp. 1-22, Jan. 2004.
  • D. Chen, Y. Chiang, N. Memon, X. Wu, “Alphabet partitioning techniques for semi-adaptive Huffman coding of large alphabets”, IEEE Trans. on Communications, vol. 55, no. 3, March 2007.
  • S. Forchhammer, X. Wu, and J. D.  Andersen, "Optimal context quantization in lossless compression of image data sequences", IEEE Trans. on Image Processing, vol. 13, no. 4, pp. 509-517, Apr. 2004.
  • X. Wu, ``Optimal binary vector quantization via enumeration of covering codes'', IEEE Trans. on Information Theory, vol. 43, no. 2, pp. 638-645, March 1997.
  • X. Wu, "YIQ vector quantization in a new color palette architecture", IEEE Trans. on Image Processing, vol. 5. no. 2, pp. 321-329, 1996.
  • X. Wu and K. Zhang, "Quantizer monotonicities and quantizer design algorithms", IEEE Trans. on Information Theory, vol. 39, no. 3, pp. 1049-1053, May 1993.
  • X. Wu, "Color quantization by dynamic programming and principal analysis", ACM Trans. on Graphics, vol. 11, no. 4 (TOG special issue on color), pp. 348-372, Oct. 1992.
  • X. Wu, "On convergence of Lloyd's method I", IEEE Trans. on Information Theory, vol. 38, no. 1, pp. 171-174, Jan. 1992.
  • X. Wu, "Optimal quantization by matrix-searching," Journal of Algorithms, vol. 12, no. 4, pp. 663-673, Dec. 1991.

 

Image Coding

 

  • X. Wu, S. Dumitrescu, and N. Zhang, "On multirate optimality of JPEG 2000 code streams", IEEE Trans. on Image Processing, vol. 14, no. 12, pp. 2012-2023, Dec. 2005.
  • N. Sarshar and X. Wu, “On rate-distortion models for natural images”, IEEE Trans. on Image Processing, vol. 16, no. 5, pp. 1383-1394, May 2007.
  • N. Zhang and X. Wu, “Lossless compression of color mosaic images”, IEEE Trans. on Image Processing, vol. 15, no. 6, pp. 1379-1388, June 2006.
  • W. Ding, F. Wu, X. Wu, and S. Li, “Adaptive directional lifting-based wavelet transform for image coding ”, IEEE Trans. on Image Processing,  vol. 16, no. 2, Feb. 2007.
  • X. Xue and X. Wu, “Directly operable image representation of multiscale primal sketch”, IEEE Trans. on Multimedia, vol. 7, no. 5, pp. 805-816, Oct. 2005
  • S. Cheng, Z. Xiong, and X. Wu, ``Fast trellis coded color quantization of images'', Real-Time Imaging, vol. 8, pp. 265-275, August 2002.
  • X. Wu and N. Memon, "Lossless interframe image compression via context modeling", IEEE Trans. on Image Processing, vol. 9, no. 5, pp. 994-1001, May 2000.
  • X. Wu and P. Bao, "-constrained high-fidelity image compression via adaptive context modeling", IEEE Trans. on Image Processing, vol. 9, no. 4, pp. 536-542, April 2000.
  • X. Wu, J. Wen, and W-H Wong, "Conditional entropy coding of VQ indexes for image compression", IEEE Trans. on Image Processing, vol. 8, no. 8, pp. 1005-1013, Aug. 1999.
  • Z. Xiong and X. Wu, "Wavelet image coding using trellis coded space-frequency quantization", IEEE Signal Processing Letters, pp. 158-161, July 1999.
  • P. Bao and X. Wu, ``-constrained near-lossless image compression using weighted finite automata encoding'', Computers and Graphics, vol. 22, no. 2, pp. 217-223, June 1998.
  • X. Wu, "Lossless compression of continuous-tone images via context selection, quantization, and modeling'', IEEE Trans. on Image Processing, vol. 6, no. 5, pp. 656-664, May 1997.
  • X. Wu and N. Memon, ``Context-based, adaptive, lossless image codec'', IEEE Trans. on Communications, vol. 45, no. 4, pp. 437-444, April 1997.
  • N. Memon and X. Wu, ``Recent developments in context-based predictive techniques for lossless image compression'', The Computer Journal, vol. 40, no. 2/3, pp. 127-136, 1997.
  • X. Wu and Y. Fang, "A segmentation-based predictive multiresolution image coder", IEEE Trans. on Image Processing, vol. 4, no. 1, pp. 34-47, 1995.
  • X. Wu, "Image coding by adaptive tree-structured segmentation", IEEE Trans. on Information Theory, vol. 38, no. 6, pp. 1755-1767, Nov. 1992.

 

Image and Signal Processing

 

  • X. Zhang, X. Wu, “Image interpolation by adaptive 2D autoregressive modeling and soft-decision estimation”, IEEE Trans. on Image Processing, vol. 17, no. 6, pp. 887-896, June 2008.
  • L. Zhang, X. Wu and D. Zhang, “Color reproduction from noisy CFA data of single sensor digital cameras”, IEEE Trans. on Image Processing, vol. 16, no. 9, pp. 2184-2197, Sept. 2007.
  • X. Wu and L. Zhang, “Color video demosaicking via motion estimation and data fusion”, IEEE Trans. on Circuit and Syst. for Video Tech., vol. 16, no.2, pp. 231-240, Feb. 2006.
  • X. Wu and L. Zhang, “Improvement of color video demosaicking in temporal domain,” IEEE Trans. Image Processing, vol.15, no.10, Oct. 2006.
  • L. Zhang and X. Wu, “Image interpolation via directional filtering and data fusion,” IEEE Trans. Image Processing, vol.15, no.8,  pp. 2226-2238, Aug. 2006.
  • X. Wu and N. Zhang, “Primary-consistent soft-decision color demosaicking for digital cameras", IEEE Trans. on Image Processing, vol. 13, no. 9, pp. 1263-1274, Sept. 2004.
  • L. Zhang and X. Wu, "Color demosaicking via directional linear minimum mean square-error estimation", IEEE Trans. on Image Processing, vol. 14, no. 12, pp. 2167-2178, Dec. 2005.
  • P. Bao, L. Zhang and X. Wu, “Canny edge detection enhancement by scale multiplication,” IEEE Trans. Pattern Analysis and Machine Intelligence, vol. 27, no. 9, pp. 1485-1490, Sept. 2005.
  • L. Zhang, P. Bao, and X.Wu, “Multiscale-LMMSE-based image denoising with optimal wavelet selection”, IEEE Trans. on Circuit and Syst. for Video Tech., vol. 15, no. 4, pp. 496-481, Apr. 2005.
  • L. Zhang, X. Wu, Q. Pan and H. Zhang, "Multiresolution modeling and estimation of multisensor data", IEEE Trans. on Signal Processing, pp. 3170-3182, Nov. 2004.
  • L. Zhang, P. Bao, and X. Wu, "Wavelet-based estimation of fractional Brownian motion embedded in noisy environment", IEEE Trans. on Information Theory, vol. 50, no. 9,  pp. 2194-2200, Sept. 2004.
  • L. Zhang, X. Wu, and P. Bao, "Noisy signal compression by wavelet transform with optimal downsampling", International Journal of Wavelets, Multiresolution and Information Processing, vol. 1, no. 4, pp. 407-423, Dec. 2003.
  • L. Zhang, P. Bao, and X.Wu, ”Hybrid inter- and intra-wavelet scale image restoration”, Pattern Recognition, p. 1737-1746, vol. 36 (8), Aug. 2003.

 

Biomedical Imaging

 

  • X. Wu and T. Qiu, “Wavelet coding of volumetric medical images for high throughput and operability”, IEEE Trans. on Medical Imaging, vol. 24, no. 6, pp. 719-727, June 2005.
  • X. Wu, S. Dumitrescu, P. Biyani, and Q. Wu, “Fast chromosome karyotyping by auction algorithm”, Int. J. of Bioinformatics and Applications, vol. 2, no. 3, 2006.
  • P. Biyani, X. Wu and A. Sinha, “Joint classification and pairing of human chromosomes”, IEEE/ACM Trans. on Computational Biology and Bioinformatics, vol. 2, no. 2, pp. 102-109, Apr. 2005.
  • Z. Xiong, X. Wu, S. Cheng, and J. Hua, "Lossy-to-lossless compression of medical volumetric data using 3D integer wavelet transforms", IEEE Transactions on Medical Imaging, vol. 22, pp. 459-470,  March 2003.

 

Steganalysis and Watermarking

 

  • S. Dumitrescu and X. Wu, “A new framework of LSB steganalysis of digital media”, IEEE Trans. on Signal Processing, vol. 53, no. 10, pp. 3923-3935, Oct., 2005.
  • S. Dumitrescu, X. Wu, and Z. Wang, "Detection of LSB steganography via sample pair analysis", IEEE Transactions on Signal Processing,  pp. 1995-2007, July 2003.
  • X. Wu, "Semantically transparent fingerprinting for copyright protection of digital cinema", Proc. of 2003 SPIE Conference on Electronic Imaging, Santa Clara, CA., vol. 5020, pp. 574-579, Feb. 2003.