Plenary Lecture
JPEG Algorithm Adjustment for Different Quality Metrics
Professor Milan Tuba
University Megatrend Belgrade
Faculty of Computer Science
Serbia
E-mail: tuba@ieee.org
Abstract: JPEG algorithm is most widely used method for lossy digital image compression. It facilitated digital image revolution during the last decade. JPEG is not a fixed algorithm but a set of recommendations that can be adjusted for particular applications. One of the most often used JPEG adjustments is selection of the quantization tables that determine not only the degree of compression, but also other characteristics of the compressed image since the quantization tables remove or attenuate some frequency components of the image. By increasing the degree of compression the quality of the image decreases, but important question remains of what is the appropriate measure of the image quality. Most often it is a subjective human perception that can be somehow objectivized by statistical survey, but for many specific applications that quality measure is not relevant. Examples include medical images (usually from alternative imaging sources like ultrasound or x-ray) and specific image analysis like edge detection, image segmentation (by multilevel thresholding), biometrics (iris recognition using Hough transform and polar representation) etc. In such cases different objective metrics for compressed image quality are introduced and tested with different quantization matrixes. Such testing lead to exponential combinatorial problems that can only be solved by using some optimization metaheuristics.
Brief Biography of the Speaker: Milan Tuba is Professor of Computer Science and Provost for mathematical, natural and technical sciences at Megatrend University of Belgrade. He received B. S. in Mathematics, M. S. in Mathematics, M. S. in Computer Science, M. Ph. in Computer Science, Ph. D. in Computer Science from University of Belgrade and New York University. From 1983 to 1994 he was in the U.S.A. first as a graduate student and teaching and research assistant at Vanderbilt University in Nashville and Courant Institute of Mathematical Sciences, New York University and later as an Assistant Professor of Electrical Engineering at Cooper Union Graduate School of Engineering, New York. During that time he was the founder and director of Microprocessor Lab and VLSI Lab, leader of scientific projects and supervisor of many theses. From 1994 he was Assistant professor of Computer Science and Director of Computer Center at University of Belgrade, from 2001 Associate Professor, Faculty of Mathematics, and from 2004 also a Professor of Computer Science and Dean of the College of Computer Science, Megatrend University Belgrade. He was teaching more than 20 graduate and undergraduate courses, from VLSI Design and Computer Architecture to Computer Networks, Operating Systems, Image Processing, Calculus and Queuing Theory. His research interest includes mathematical, queuing theory and heuristic optimizations applied to computer networks, image processing and combinatorial problems. He is the author or coauthor of more than 130 scientific papers and coeditor or member of the editorial board or scientific committee of number of scientific journals and conferences. Member of the ACM since 1983, IEEE 1984, New York Academy of Sciences 1987, AMS 1995, SIAM 2009.