Algorithms for Compression of High Dynamic Range Images and Video by Vladimir Dolzhenko A Doctoral Thesis Submitted in partial fulfilment of the requirements for the award of Doctor of Engineering of Loughborough University 31.05.2015 © by Vladimir Dolzhenko 2015 Abstract The recent advances in sensor and display technologies have brought upon the High Dynamic Range (HDR) imaging capability. The modern multiple exposure HDR sensors can achieve the dynamic range of 100-120 dB and LED and OLED display devices have contrast ratios of 105:1 to 106:1. Despite the above advances in technology the image/video compression algorithms and associated hardware are yet based on Standard Dynamic Range (SDR) technology, i.e. they operate within an effective dynamic range of up to 70 dB for 8 bit gamma corrected images. Further the existing infrastructure for content distribution is also designed for SDR, which creates interoperability problems with true HDR capture and display equipment. The current solutions for the above problem include tone mapping the HDR content to fit SDR. However this approach leads to image quality associated problems, when strong dynamic range compression is applied. Even though some HDR-only solutions have been proposed in literature, they are not interoperable with current SDR infrastructure and are thus typically used in closed systems. Given the above observations a research gap was identified in the need for efficient algorithms for the compression of still images and video, which are capable of storing full dynamic range and colour gamut of HDR images and at the same time backward compatible with existing SDR infrastructure. To improve the usability of SDR content it is vital that any such algorithms should accommodate different tone mapping operators, including those that are spatially non-uniform. In the course of the research presented in this thesis a novel two layer CODEC architecture is introduced for both HDR image and video coding. Further a universal and computationally efficient approximation of the tone mapping operator is developed and presented. It is shown that the use of perceptually uniform colourspaces for internal representation of pixel data enables improved compression efficiency of the algorithms. Further proposed novel approaches to the compression of metadata for the tone mapping operator is shown to improve compression performance for low bitrate video content. Multiple compression algorithms are designed, implemented and compared and quality-complexity trade-offs are identified. Finally practical aspects of implementing the developed algorithms are explored i by automating the design space exploration flow and integrating the high level systems design framework with domain specific tools for synthesis and simulation of multiprocessor systems. The directions for further work are also presented. Vladimir Dolzhenko, 31st May 2015 ii Acknowledgements I would like to express my special appreciation to my advisor Dr Eran Edirisinghe who has been tremendous mentor to me over all these years. Without his help, advice and encouragement completing this work would not be possible. I would like to thank Dr Helmut Bez for his course and guidance during annual reviews. I would like to thank my sponsoring company Apical Ltd, its CEO Dr Michael Tusch and the industrial supervisor Dr Slava Chesnokov for all the help with tuition fees and for providing priceless experience of understanding and designing imaging algorithms and complex systems. Thanks to their understanding at the times when the University assignments clashed with the hard deadlines. I would like to thank all the staff of Loughborough University Systems Engineering Doctorate Centre for brilliant management of the programme and for providing world class training in systems engineering. Specific thanks to Dr Stuart Burdges for excellent introduction to Systems Engineering. I am thankful to all my fellow students, it was fun time together and I have learned a lot from you. A special thanks to my family. I am very grateful to my mother-in-law, father-in-law, my mother and father for all their help, encouragement and understanding. I would like to specifically thank my beloved wife Anastasia Lazareva for all her help, encouragement and belief in me. It is because of you I did not give up on this work. After all the sacrifices you did on my behalf it is your thesis as well. Vladimir Dolzhenko, 31st May 2015 iii Table of contents Abstract ....................................................................................................................................... i Acknowledgements .................................................................................................................. iii Table of contents ....................................................................................................................... iv Abbreviations ........................................................................................................................... vii List of figures ............................................................................................................................ xi List of tables ............................................................................................................................. xii Chapter 1 Introduction .......................................................................................................... 1 1.1 Research problem ........................................................................................................ 1 1.2 Sponsoring company ................................................................................................... 2 1.3 Research aim and objectives ....................................................................................... 2 1.4 Chapter description ..................................................................................................... 3 1.5 Research contribution .................................................................................................. 4 Chapter 2 Background .......................................................................................................... 6 2.1 Introduction ................................................................................................................. 6 2.2 H.264/AVC Video coding standard ............................................................................ 6 2.3 Scalable Video Coding. ............................................................................................... 8 2.4 H.265 High efficiency video coding ......................................................................... 11 2.5 High dynamic range imaging .................................................................................... 14 2.6 Complexity of the compression algorithms .............................................................. 15 Chapter 3 Literature Review............................................................................................... 17 3.1 Introduction ............................................................................................................... 17 3.2 HDR image compression .......................................................................................... 18 3.3 HDR video compression ........................................................................................... 21 3.4 Alternative compression schemes ............................................................................. 24 3.5 System design ............................................................................................................ 25 Chapter 4 High Dynamic Range Still Image Compression ................................................ 29 iv 4.1 Introduction. .............................................................................................................. 29 4.2 Overall codec structure.............................................................................................. 30 4.3 Experimental setup .................................................................................................... 37 4.4 Experimental results .................................................................................................. 40 4.5 Conclusion ................................................................................................................. 43 Chapter 5 High Dynamic Range Video Compression ........................................................ 45 5.1 Introduction ............................................................................................................... 45 5.2 Overview of the proposed method ............................................................................ 45 5.3 The proposed CODEC .............................................................................................. 46 5.4 Experimental setup .................................................................................................... 51 5.5 Experimental results .................................................................................................. 53 5.6 Conclusion ................................................................................................................. 55 Chapter 6 Integration of the SysML Design Framework with a Domain-Specific Modelling System .................................................................................................................... 56 6.1 Introduction ..............................................................................................................