Laser Scanning Book Review

Greetings! This month, I would like to review the recently published (Summer 2010) book Airborne and Terrestrial Laser Scanning, edited by Vosselman and Maas. No, I wasnt paid to do this review (although I probably should have asked for a check!). I used this as the text book for my Digital Terrain Modeling class this year, which I think helped me to greatly improve the course from its first offering in Winter 2010.

Overall, I strongly recommend this text for anyone working with laser scanning. Even if you are an expert in laser scanning, there will be a lot you can learn from this text. It will refine your understanding of key concepts and ultimately improve your ability to work with laser scan data.

As you may be aware, there are very few texts related to laser scanning available, which is not surprising given how fast the technology changes. However, while new methods will always be available, this book contains a lot of information regarding LIDAR principles that can be important for a laser scan operator, someone processing LIDAR data, or for someone using processed LIDAR data for an application.

Each chapter in the book was written by a different author who is an expert in the specific topic of the chapter. An important feature of this text is the color figures, which as you probably know, is important to displaying LIDAR data whether you are mapping photographic color, intensity values, height, etc. The cost of color printing is offset by advertisements printed at the end of each chapter so the book doesnt cost you a fortune!

Obviously anyone can find flaws or differences of opinion with any book and so I do not intend to discuss those in this review. Rather, I would like to concentrate on its strengths and applicability. Overall, any weaknesses are insignificant when compared to the strengths. I will say, however, that the text does tend to focus more on airborne scanning than terrestrial, but there is a lot of common ground between the two systems.

Chapter 1 discusses fundamental s of laser scanning including very detailed discussions of optics, peak detection, phase measurements, laser beam propagation, full wave form diagnostics, etc. The discussion is also augmented by a discussion of LIDAR systems used for bathymetric mapping.
Chapter 2 presents a great discussion of visualization and efficient data structures for point clouds. While many users of LIDAR take these for granted since they are integrated into the software used to navigate point clouds, those of us who develop our own code for specialized processing can certainly appreciate it. This chapter also discusses segmentation and creating geometric primitives from laser scan data.

Chapter 3 is a very thorough, rigorous discussion of registration, calibration, and measurement error filled with a substantial amount of valuable information. Transformation matricies and quaternions for integrating the components of LIDAR systems are presented. Problems with scan data including blooming, mixed pixels, and saturation are discussed. The section also discusses algorithms for point cloud alignment and comparisons to target-based approaches.

Chapter 4 discusses the creation of digital terrain models along with an in-depth discussion of ground filtering methods. Chapter 5 discusses extraction of buildings (simple geometric primitives) from the LIDAR point clouds for urban mapping projects. The end of this chapter also provides insights into data exchange formats, something that is currently difficult in the LIDAR/3D modeling realm. The recently developed E57 format should alleviate some of these problems when it is incorporated into commercial software.

Chapters 6-8 provide examples and discussions of LIDAR application to forestry, engineering, and cultural heritage applications, respectively. With our DTM class, we have students from a variety of backgrounds, so these chapters are helpful to get them to open their eyes and think about different ways this technology can be applied in disciplines other than their own. Chapter 9 concludes with a chapter discussing mobile mapping and how that will continue to revolutionize the laser scanning industry.

Overall, I think this book is an important step towards better laser scanning education in university curricula. The technical information presented in the book is difficult for a first exposure to LIDAR by students; however, this allows it to be a resource they can continually refer to as they progress in their career working with LIDAR.

So I will warn those of you who are new to LIDAR it may overwhelm you at first. However, just like anything else in life, take it a step at a time. If you find yourself overwhelmed, skip to chapters 6 through 8 and read about all of the applications of LIDAR! The exciting images in those chapters will encourage you to go back, read, and learn the technical material in the previous chapters. And as you can see from the picture, I recommend the book for all ages!