First International Workshop on Multimedia Analysis and Processing

(IMAP 2007)

Turtle Bay Resort, Honolulu, Hawaii, USA

  

August 15-16, 2007

Technical Sponsored by:

IEEE Visual Signal Processing and Communications Technical Committee

 

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IMAP 2007 Keynote Talk

Perception Is Reality: Visual Quality Evaluation and Beyond

 

Weisi Lin

School of Computer Engineering, Nanyang Technological University, Singapore

 

Abstract:  As a result of strong market, technology and standardization drives, digital visual contents have been immersing into our work and life at an explosive rate. Visual signal may be acquired, synthesized, enhanced, watermarked, compressed, transmitted, stored, reconstructed, retrieved, authenticated and presented for various applications and services. Since the human visual system (HVS) is the ultimate receiver and appreciator for the majority of processed images and video, a perceptual quality criterion should be used in the system design and optimization, instead of a traditional, mathematically defined one (e.g., MSE, SNR, PSNR or their relative). As a result of the evolution, the HVS develops unique characteristics, which can be turned into the advantages of system designs. To make the machine perceive as the HVS does can result in resource savings (e.g., bandwidth, memory space, computing power) and performance enhancement (such as the resultant visual quality, and new functionalities).

How to evaluate the quality of visual signal plays a central role (explicitly or implicitly) in shaping many visual processing algorithms and systems, as well as their implementation and optimization. A traditional quality measure does not align with the HVS perception because of 1) not every difference in an image noticeable; 2) not every difference receiving same attention level. Significant research effort has been made toward modeling the HVS¡¯ picture quality evaluation during the past decade, to tackle the abovementioned two problems of a traditional measure, and to apply the resultant models to various applications. Some systems have begun to find their uses in industries.

In this talk, we aim at a review, systematic analysis, sharing of research and industrial experience, and discussion of our views for future research, in the related fields. We will start with briefing the relevant physiological and psychological knowledge towards the HVS¡¯ visual quality perception, and presenting the research effort in formulating the two basic psychophysical phenomena¡ªjust-noticeable difference (JND) and visual attention (VA). JND and VA account for the local and global characteristics of the HVS in appreciating an image, respectively, and their models can be combined to derive the overall visual sensitivity.  A taxonomy and overview is then given for the existing perceptual visual quality metrics (PVQMs). The applications of perceptual quality evaluation techniques are to be presented in signal compression and enhancement. In addition, the relevant industrial deployment will be highlighted. The last part of the talk will give our comments of the current progress, points of further discussion and possible future research directions.

 

Bio: Weisi Lin graduated from Zhongshan University, China with B.Sc and M.Sc in 1982 and 1985, respectively, and from King¡¯s College, London University, UK with Ph.D in 1992. He taught and researched in Zhongshan University, Shantou University (China), Bath University (UK), National University of Singapore, Institute of Microelectronics (Singapore), Centre for Signal Processing (Singapore), and Institute for Infocomm Research (Singapore). He has been the project leader of 12 successfully-delivered projects in digital multimedia technology development. Currently, he is an Associate Professor in School of Computer Engineering, Nanyang Technological University in Singapore. His areas of expertise include image processing, video and audio compression, multimedia communication, computer vision, and embedded/parallel systems. He is a senior member of IEEE, a member of IET and a Chartered Engineer (UK).

 

Since 2003, Weisi Lin has devoted to PVQM development and perception-based visual processing. With the topics closely related to the talk, he holds nine patents and has published more than 70 technical publications in international refereed journals and conferences (for JND/VA modeling, full-reference and no-reference metrics, perceptual image/video compression, HVS-based signal enhancement, etc.). He has also been the project leader of 5 industrial projects for various types of PVQMs, and maintained active long-term working relationship with the companies which are keen in perception-based technology.