Book Reviews

Digital Video Image Quality and Perceptual Coding

J. Electron. Imaging. 16(3), 039901 (August 31, 2007). doi:10.1117/1.2778686
History: Published August 31, 2007
Text Size: A A A

Open Access Open Access

A major aim in designing image and video coding systems is to use minimal resources to achieve the highest visual quality with respect to certain constraints such as bit rate and complexity. In most situations, the final evaluation of the quality of processed, transmitted, and displayed images and video is made by the human visual system (HVS). It is essentially futile to spend significant effort on encoding information that is beyond human perception. The use of HVS-based quantitative quality or impairment metrics could lead to lower bit rates for visual applications, resulting in lower costs and fewer coding distortions.

The editors of this book, Wu and Rao, take an HVS-based approach in outlining the principles, metrics, and standards associated with perceptual coding. They also present the latest techniques and applications. The book presents works of experts in the field and consists of 18 chapters organized into three parts. The first part provides the fundamentals; the second part covers picture quality assessment and metrics while the third part focuses on applications.

The first part consists of three chapters covering some fundamental theory, concepts, and techniques on picture coding and HVS. The first chapter provides a foundation on image and video compression, along with coding techniques and international coding standards. The second chapter introduces fundamentals of human vision and vision modeling and also discusses some recent developments in vision research relevant to digital image coding. The third chapter comprehensively discusses numerous coding artifacts and distortions introduced by image/video coding and compression algorithms.

The second part of the book consists of eight chapters covering topics concerning image quality assessment criteria, subjective/objective methods and metrics, test procedures, and current developments in international standards. This section begins with a chapter that provides an in-depth discussion on subjective assessment methods and tests including the experimental design of subjective assessment tests and the use of standard test images and video sequences. Related issues in digital video coding and communications are also discussed. The fifth chapter provides a comprehensive and up-to-date overview on perceptual video metrics including traditional measures and recent HVS-based metrics. Factors that affect human viewer assessment on picture quality are also discussed. The sixth to tenth chapters cover the following picture quality assessment methods:

  • Picture quality scale (PQS) and its application to digital picture services including super-HDTV, cellular video phones, etc.
  • Structural similarity-based image quality assessment, which targets perceived structural information variations, mimicking the high-level functionality of HVS.
  • Vision model-based digital video impairment metrics, which achieve accurate assessment of blocking and ringing artifacts as the vision model emulates the mechanisms of visual quality/distortion perception in the HVS.
  • Just-noticeable-difference (JND) models, where JND estimation refers to the maximum distortion in the transform and spatial domains that the HVS cannot perceive.
  • No-reference quality metric for degraded and enhanced video, which highlights the importance of assessing picture quality enhancement as well as degradation in applications where the original pictures are not available.

  • Picture quality scale (PQS) and its application to digital picture services including super-HDTV, cellular video phones, etc.
  • Structural similarity-based image quality assessment, which targets perceived structural information variations, mimicking the high-level functionality of HVS.
  • Vision model-based digital video impairment metrics, which achieve accurate assessment of blocking and ringing artifacts as the vision model emulates the mechanisms of visual quality/distortion perception in the HVS.
  • Just-noticeable-difference (JND) models, where JND estimation refers to the maximum distortion in the transform and spatial domains that the HVS cannot perceive.
  • No-reference quality metric for degraded and enhanced video, which highlights the importance of assessing picture quality enhancement as well as degradation in applications where the original pictures are not available.

Chapter 11 presents an overview of the Video Quality Experts Group (VQEG), highlighting its goals, activities, and future directions.

The third part of the book consists of six chapters focusing on coder designs that improve perceptual picture quality by reduction of perceived coding artifacts and transmission errors. The perceptual coders presented in Chapters 12 to 14 use sophisticated vision models resulting in significant improvement in visual performance. HVS-based models are being employed in video encoding systems to accurately estimate the visibility of video artifacts introduced by the encoder. The principles behind these HVS models and different approaches to using the models are examined in Chapter 12. Contemporary perceptual coders along with detailed discussions on model calibration and coder performance evaluation are presented in Chapter 13. Human visual sensitivity is highest around the point of fixation, also known as the foveation point, and decreases dramatically with distance from the point of fixation. Images of good perceptual quality can still be obtained by removing considerable high-frequency information redundancy from the peripheral regions. Chapter 14 presents image and video coding systems that incorporate techniques based on the foveation feature of the HVS that are able to deliver rate-scalable data streams ordered to foveation-based perceptual importance. The next two chapters present postprocessing approaches for reducing artifacts and color bleeding, which result in improved visual quality of reconstructed pictures. Chapter 17 provides an introduction to error resilient coding and concealment methods compatible with MPEG2.

The book is well written and organized despite being a compilation of chapters from different authors. It will serve as an excellent and comprehensive resource for those interested in perceptual quantitative quality/impairment metrics for digital images. Those new to the area would find that the first part provides an adequate and broad introduction to the fundamentals before they delve deeper into the subject matter. The latest developments in vision research as they relate to HVS-based image and video coding are reviewed and the final chapter considers current issues and challenges in the field for future research.

Ashraf A. Kassim is with the Electrical & Computer Engineering Department of the National University of Singapore, where he is also currently an associate dean of the School of Engineering. His research interests include video/image processing and compression, computer vision, and medical image analysis.


Citation


"Digital Video Image Quality and Perceptual Coding", J. Electron. Imaging. 16(3), 039901 (August 31, 2007). ; http://dx.doi.org/10.1117/1.2778686


Figures

Tables

References

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Related Book Chapters

Topic Collections

PubMed Articles
Advertisement
  • Don't have an account?
  • Subscribe to the SPIE Digital Library
  • Create a FREE account to sign up for Digital Library content alerts and gain access to institutional subscriptions remotely.
Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).
Access This Proceeding
Sign in or Create a personal account to Buy this article ($15 for members, $18 for non-members).
Access This Chapter

Access to SPIE eBooks is limited to subscribing institutions and is not available as part of a personal subscription. Print or electronic versions of individual SPIE books may be purchased via SPIE.org.