【题 目】 Solving Inverse Imaging Problems using Graph-Signal Smoothness Priors

【主讲人】 Professor Gene Cheung

National Institute of Informatics, Tokyo, Japan

【时 间】 2016年09月02日（周五）上午10:00

【地 点】 北京大学 计算机所大楼 106报告厅

Abstract:

Inverse imaging problems like denoising, interpolation and bit-depth enhancement are inherently ill-posed, and signal priors are often used for regularization. A recent popular prior is the graph-signal smoothness prior: a desired image patch—interpreted as a graph-signal on an appropriately chosen graph—is assumed to be smooth with respect to the underlying graph. In this talk, I will first explain why such a signal prior is sensible from a graph signal processing (GSP) perspective. Then, I will describe a new graph-signal smoothness prior called LERaG based on left eigenvectors of the random walk graph Laplacian matrix, which has many desirable image filtering properties yet is computation-efficient. Finally, I will describe how LERaG can be used for soft decoding of JPEG images, resulting in state-of-the-art restored image quality.

Biography:

Gene Cheung received the B.S. degree in electrical engineering from Cornell University in 1995, and the M.S. and Ph.D. degrees in electrical engineering and computer science from the University of California, Berkeley, in 1998 and 2000, respectively. He was a senior researcher in Hewlett-Packard Laboratories Japan, Tokyo, from 2000 till 2009. He is now an associate professor in National Institute of Informatics in Tokyo, Japan. He has been an adjunct associate professor in the Hong Kong University of Science & Technology (HKUST) since 2015.

His research interests include 3D image processing, graph signal processing, and signal processing for sleep analysis. He has served as associate editor for IEEE Transactions on Multimedia (2007--2011), DSP Applications Column in IEEE Signal Processing Magazine (2010--2014) and SPIE Journal of Electronic Imaging (2014--2016). He currently serves as associate editor for IEEE Transactions on Image Processing (2015--present), IEEE Transactions on Circuits and Systems for Video Technology (2016--present) and APSIPA Journal on Signal & Information Processing (2011--present), and as area editor for EURASIP Signal Processing: Image Communication (2011--present). He is a distinguished lecturer in APSIPA (2016--2017). He served as a member of the Multimedia Signal Processing Technical Committee (MMSP-TC) in IEEE Signal Processing Society (2012--2014), and a member of the Image, Video, and Multidimensional Signal Processing Technical Committee (IVMSP-TC) (2015--2017). He has also served as technical program co-chair of International Packet Video Workshop (PV) 2010 and IEEE International Workshop on Multimedia Signal Processing (MMSP) 2015, and symposium co-chair for CSSMA Symposium in IEEE GLOBECOM 2012. He is a co-author of the best student paper award in IEEE Workshop on Streaming and Media Communications 2011 (in conjunction with ICME 2011), best paper finalists in ICME 2011, ICIP 2011 and ICME 2015, best paper runner-up award in ICME 2012 and best student paper award in ICIP 2013 and IVMSP’16.