High Dynamic Range Imaging, Book Review

Introduction

Finally we have the first book on High Dynamic Range Imaging or “HDRI”. With a very general title like this you might be left wondering what is exactly covered within this book, and this review will help to answer that question.It’s surprising that this is the first book on HDRI – the technique of shooting HDRIs and using it to achieve photorealistic results has been an indispensable tool in the film and computer graphics industry for years. Recently many software developers have integrated HDRI support into their software making it even easier than before to use this advanced technique. We even have HDRI capable cameras and real-time HDRI appearing in computer games. So for people wishing to break into this field, this book is long overdue.

From the publishers website:

Description:

“High dynamic range imaging produces images with a much greater range of light and color than conventional imaging. The effect is stunning, as great as the difference between black-and-white and color television. High Dynamic Range Imaging is the first book to describe this exciting new field that is transforming the media and entertainment industries. Written by the foremost researchers in HDRI, it will explain and define this new technology for anyone who works with images, whether it is for computer graphics, film, video, photography, or lighting design”

Audience:

“Researchers and developers in computer graphics and the entertainment industry; technical directors in film and photography; anyone who works with images.”

Authors

The Authors, Erik Reinhard, Greg Ward, Sumanta Pattanaik and Paul Debevec are all computer scientists, professors and programmers. They are generally considered to be trailblazers or leading researchers in the field of HDRI.

Review

Please keep in mind that this review is being performed from an artist’s perspective, hence I am unable to provide much useful information regarding the more technical aspects of this book, of which there are many! For this I have spoken to one of the authors, Greg Ward, who has provided us with a more detailed insight.

The book is a quality hardcover tome of information containing healthy numbers of full color images, formulas and graphs. It also comes with a DVD full of useful resources, the contents of which are outlined below. While most chapters have a short introductory paragraph that can be understood by the layman or artist, they quickly move into the realm of highly complex formulas and code. If you’re expecting this book to have some tutorials on lighting and rendering a HDR image in 3dsmax or Lightwave you’re looking at the wrong book. The sections that do cater for the artist are mainly available online anyway, along with numberless websites that offer easy to read, quick and dirty tutorials and how-to’s.

The publisher’s description of the audience says the book is for anyone who works with images, but if you are specifically a photographer or a computer graphics artist then this book is very light on useful, practical information. If you read a chapter on removing lens flare or movement from your HDRIs it will be a technical explanation containing formulas and code, not a how-to on removing it using your favorite image editor.

Greg Ward has provided us with some more insight into who would find the book most useful, and what level of skill is required to understand and apply the concepts within:
“For the most part, our intended audience includes computer graphics students, teachers, researchers, and professionals, as well as special effects technical directors and game developers who are interested in applying HDR in their work. The book is geared towards computer graphics and vision graduate students and above (including professors, researchers, and professionals). It attempts to cover all of the fundamentals of HDR imaging and delves into some more advanced topics as well, but was not designed as a recipe book or anything of that sort. The reader is left with a fair amount of work to do to apply the concepts presented.”

Table of Contents

The following is a breakdown of each chapter and whether it is mostly technical, artistic or general.

Introduction – General. A Discussion of what HDRI is, how it is created and what it is used for.

2 Light And Color
2.1 Radiometry – Technical
2.2 Photometry – Technical
2.3 Colorimetry – Technical
2.4 Color Spaces – Technical
2.5 White Point and Illuminants – Technical
2.6 Color Correction – Artistic/Technical/General
2.7 Color Opponent Spaces – Technical
2.8 Color Appearance – Intro General but Mainly Technical
2.9 Display Gamma – Technical
2.10 Brightness Encoding – Technical
2.11 Standard RGB Color Spaces – Technical

3 HDR Image Encodings
3.1 LDR versus HDR Encodings – Technical
3.2 Applications of HDR Images – General
3.3 HDR Image Formats – Technical
3.4 HDR Encoding Comparison – Technical
3.5 Conclusions

4 HDR Image Capture
4.1 Photography and Light Measurement – General, Artistic, Technical
4.2 HDR Image Capture from Multiple Exposures – Technical, Artistic
4.3 Film Scanning – Technical, Artistic
4.4 Image Registration and Alignment – Technical
4.5 The Mean Threshold Bitmap Alignment Technique – Technical
4.6 Deriving the Camera Response Function – Technical
4.7 Ghost Removal – Technical
4.8 Lens Flare Removal – Technical
4.9 Direct Capture of HDR Imagery – General
4.10 Conclusions – General

5 Display Devices – General
5.1 Hardcopy Devices – General, Technical
5.2 Softcopy Devices – General

6 The Human Visual System and HDR Tone Mapping – General
6.1 Tone-mapping Problem – General
6.2 Human Visual Adaptation – General, Technical
6.3 Visual Adaptation Models for HDR Tone Mapping – Technical
6.4 Background Intensity in Complex Images – Technical
6.5 Dynamics of Visual Adaptation – Technical
6.6 Summary – General

7 Spatial Tone Reproduction
7.1 Preliminaries – Technical
7.2 Global Operators – Technical
7.3 Local Operators – Technical
7.4 Summary- Technical

8 Frequency Domain And Gradient Domain Tone Reproduction
8.1 Frequency Domain Operators – Technical
8.2 Gradient Domain Operators – Technical
8.3 Performance – Technical
8.4 Discussion – Technical

9 Image-Based Lighting
9.1 Introduction – General, Artistic
9.2 Basic Image-based Lighting – General, Artistic, Technical
9.3 Capturing Light Probe Images – Mainly Artistic, Some Technical
9.4 Omnidirectional Image Mappings – Technical
9.5 How a Global Illumination Renderer Computes IBL Images – Technical
9.6 Sampling Incident Illumination Efficiently – Technical, Artistic
9.7 Simulating Shadows and Scene-Object Interreflection – Mainly Technical, Some Artistic
9.8 Useful IBL Approximations – Mainly Technical, Some Artistic
9.9 Image-based Lighting for Real Objects and People – General, Technical
9.10 Conclusions – General

DVD

The book includes a DVD, which contains 4 gigs worth of resources that are easily navigated via a html browser. The contents include:

• HDR Images in various formats (very large number of images)
• Executables and a set of libraries for converting images between Radiance HDR and JPGHDR format developed by Greg Ward at SunnyBrook Tech.
• Source Code and exes for more than 20 tone reproduction operators.
• IBL tutorial using Radiance by Paul Debevec (very simple)

Other Notes

While this book mainly caters for the technically minded, there are several gems such as links for providers of leading edge HDRI capable still and video cameras, and a list of chrome ball manufacturers. HDRI hardware and software is also touched on as well as an interesting chapter on the human visual system.

Conclusion

For the artist or photographer we are still waiting for that first HDRI book, but for the computer scientist or programmer this book is definitely for you. It’s hard to beat a book written about HDRI by the pioneers of HDRI.

I hope this short review has proved to be helpful.

“High Dynamic Range Imaging” is currently available at Amazon.com