Perceptually-Tuned Signal Processing

In applications involving speech, audio and images, the final judge of quality is a human being. Consequently, it is important that signal processing systems in such application takes into account how humans perceive the final output. My group has studied ways of incorporating known properties of the human perceptual system in image and audio processing problems. Some of our activities include:

1. In some of our early work, done in collaboration with Professor Tom Stockham at the University of Utah, we developed image compression techniques that incorporated models of the human visual system in the performance function. Methods based on vector quantization and subband decomposition of the images and new models for the perceptual masking function were developed in this work.
2. I have a long-standing consulting relationship with Sonic Innovations, a manufacturer of digital hearing aids, in the area of feedback suppression and noise reduction for hearing aids. Our emphasis has been on developing algorithms that utilizes information about the perceptual detection threshold function and the auditory masking function for these purposes.
3. With my collaborators at the Yonsei University, Seoul, Korea, my students and I are currently exploring effective means of binaural rendering in three-dimensional audio systems.

The National Science Foundation, NASA and the Korean Science Foundation have funded our work in this area. I collaborate with faculty members in the Department of Communication Disorders and researchers at Sonic Innovations for experimental work on hearing aid signal processing.

Graduate Students With Research Emphasis in Audio and Image Processing

• Peter J. Hahn, Perceptually Lossless Image Compression, Ph. D., University of Utah, December 1999.
• Ramin Baseri, Vector Quantization Employing Perceptual Masking Functions, M. S., University of Utah, September 1991.
• Osama Haddadin, A Hexagonally Oriented Frequency Selective Human Visual System Model and its Application to Image Coding, M. S., University of Utah, August 1992.
• Bhupal Dharia, Design of Filter Banks for Subband Coding Systems, M. S., University of Utah, March 1994.
• K. S. Prashant, Design of a Perceptual Threshold Model and Parallel Algorithms for Image Compression, M. S., University of Utah,
  March 1995.
• Shan Mo, Adaptive Quadratic Preprocessing of Document Images for Binarization, M. S., University of Utah August 1997.
• Ying Deng, Adaptive Algorithms for Speech Enhancement, Ph. D., University of Utah, December 2006.
• Ashutosh Pandey, Adaptive Feedback Cancellation Techniques for Digital Hearing Aids, Ph. D, University of Utah, Expected year of
  graduation: 2008.

Publications in Audio and Image Processing

1. V. J. Mathews, "Multiplication Free Vector Quantization Using the L _1 distortion Measure and its Variants,'' IEEE Trans. Image Proc., Vol. 1, No. 1, pp. 11-17, January 1992.
2. J. N. Bradley, T. G. Stockham, Jr., and V. J. Mathews, "An Optimal Design Procedure for Intraband Vector Quantized Subband Coding,'' IEEE Trans. Communications, Vol. 43, No. 2, pp. 523-533, February 1995.
3. V. J. Mathews and P. J. Hahn, "Vector Quantization Using the L_infinity Distortion Measure,'' IEEE Signal Processing Letters, Vol. 4, pp. 33-35, February 1997.
4. S. Mo and V. J. Mathews, "Adaptive, Quadratic Preprocessing of Document Images for Binarization,''  IEEE Trans. Image Processing, Vol. 7, No. 7, pp. 992-999, July 1998.
5. A. Polesel, G. Ramponi and V. J. Mathews, "Image Enhancement via Adaptive Unsharp Masking,'' IEEE Trans. Image Processing , Vol. 9, No. 3, pp. 505-510, March 2000.
6. Y. Deng, V. J. Mathews and B. Farhang-Boroujeny, "Low-Delay Nonuniform Pseudo QMF Banks with Application to Speech Enhancement", IEEE Transactions on Signal Processing, vol. 55, no. 5, pp. 2110-2121, May 2007.
7. H. I. K. Rao, V. J. Mathews and Y. -C. Park, "A Minimax Approach for the Joint Design of Acoustic Crosstalk Cancellation Filters,"
   IEEE Transactions on Audio, Speech and Language Processing, vol. 15, no. 8,  pp. 2287 - 2298, Nov. 2007

8. V. J. Mathews, R. W. Waite and T. D. Tran, "Predictive Vector Quantization of Images Using a Constrained 2-D Autoregressive Predictor," Proc. 20th Annual Asilomar Conf. Signals, Systems and Computers, Pacific Grove, California, pp. 243-247, November 10-12, 1986.
   
9. V. J. Mathews, R. W. Waite and T. D. Tran, "Image Compression Using Vector Quantization of Linear (One-Step) Prediction Errors," Proc. IEEE Int. Conf. Acoust., Speech, Signal Proc., pp. 733-736, Dallas, Texas, April 6-9, 1987.
   
10. V. J. Mathews and M. Khorchidian, "Multiplication-Free Vector Quantization Using the L _l Distortion Measure and its Variants," Proc. IEEE Int. Conf. Acoust., Speech, Signal Proc., pp. 1747-1750, Glasgow, May 23-26, 1989.
    
11. R. Baseri and V. J. Mathews, "Vector Quantization of Images using Visual Masking Functions, Proc. IEEE Int. Conf. Acoust., Speech, Signal Proc., San Francisco, California, pp. III 365-368, March 1992.
    
12. O. S. Haddadin, V. J. Mathews, and T. G. Stockham, "Subband Vector Quantization of Images using Hexagonal Filter Banks," Proc. Data Compression Conference, Snowbird, Utah, March 1992.
    
13. K. S. Prashant and V. J. Mathews, "A Massively Parallel Algorithm for Vector Quantization," Proc. of the 1995 NASA Space and Earth Sciences Workshop, Salt Lake City, Utah, March 1995.
    
14. K. S. Prashant, V. J. Mathews and P. J. Hahn, "A New Model of Perceptual Threshold Functions for Application in Image Compression Systems," Proceedings of the IEEE Data Compression Workshop, Snowbird, Utah, March 1995.
    
15. J. T. Yoo, G. C. Gopalakrishnan, K. F. Smith and V. J. Mathews, "High Speed Counterflow-Clocked Pipelining Illustrated on the Design of HDTV Subband Vector Quantizer Chips,"  Proc. Conference on Advanced Research in VLSI, Chapel Hill, North Carolina, March 1995.
    
16. S. Mo and V. J. Mathews, "Adaptive Binarization of Document Images," Proceedings of the IEEE Workshop on Nonlinear Signal and Image Processing , Neos-Marmaras, Halkidiki, Greece, June 1995.
    
17. V. J. Mathews, "Vector Quantization of Images Using the L_infinity Distortion Measure," Proceedings of the IEEE International Conference on Image Processing, Washington, D. C., October 1995.
    
18. P. J. Hahn and V. J. Mathews, "Perceptually Lossless Image Compression," Proc. Data Compression Industry Workshop, Snowbird, Utah, March 1997.
    
19. A Polesel, G. Ramponi and V. J. Mathews, "Adaptive Unsharp Masking for Contrast Enhancement," IEEE Int. Conf. Image Processing, Santa Barbara, California, September 1997.
    
20. P. Hahn and V. J. Mathews, "A Perceptually Tuned Image Compression System," Proc. Eighth IEEE DSP Workshop, Bryce Canyon, Utah, August 1998.
21. P. Hahn and V. J. Mathews, "An Analytical Model of the Perceptual Threshold Function for Multichannel Image Compression," Proc. IEEE Int. Conf. Image Proc., Chicago, October 1998.
22. A. Pandey and V. J. Mathews, "Howling Suppression in Hearing Aids using Least-Squares Estimation and Perceptually Motivated Gain Control'', Proc. IEEE Int. Conf. Acoustics, Speech & Signal Proc., vol. 5, pp. 149-152, Toulouse, France, April 2006.
23. H. Rao, V. J. Mathews and Y.-C. Park, "Inverse Filter Design Using Minimax Approximation Techniques for 3-D Audio", Proc. IEEE Int. Conf. Acoustics, Speech & Signal Proc., vol. 5, pp. 353-356, Toulouse, France, April 2006.
24. H. Rao, V. J. Mathews and Y.-C. Park, "A Joint Minimax Approach for Binaural Rendering of Audio Through Loudspeakers", Proc. IEEE Int. Conf. Acoustics, Speech & Signal Proc., Hawaii, April 2007.
25. Y. Deng, V. J. Mathews and B. Farhang-Boroujeny, "The Design of Low-Delay Nonuniform Pseudo QMF Banks," Proc. Fourteenth European Signal Processing Conference, Florence, Italy, September 4-8, 2006.
26.  Y. Deng and V. J. Mathews, "Subband Particle Filtering for Speech Enhancement," Proc. Fourteenth European Signal Processing Conference, Florence, Italy, September 4-8, 2006.
    
27. A. Pandey, V. J. Mathews, M. Nilsson, "Adaptive Gain Processing to Improve Feedback Cancellation in Digital Hearing Aids," accepted for publication in the Proc. IEEE Int. Conf. Acoustics, Speech \& Signal Processing, Las Vegas, April 1-4, 2008.