The purpose of this book is to serve as a starting point for people interested in volume rendering. It is not a textbook of the type that has exercises at the end of each chapter. Instead, it presents this subfield of computer graphics and imaging in a precise and straightforward manner.

Chapter 1 introduces the rendering pipeline, the main subject of the book. Each chapter after the first has a topic related to a stage in the rendering pipeline. Chapter 2 deals with projections, coordinate transformation, and the general idea of ray casting. Chapter 3 is on illumination and shading. The point is clearly made that photorealism is not the goal because there is no reference in the real world when rendering the inside of a volume. Chapter 4 is about classification, coloring, and segmentation--the operations that make it possible to see structures inside a volume without explicitly identifying a surface for rendering. Chapter 5, “Interpolation,” describes the process of sampling along the ray using different kernels. Chapter 6 is on the compositing step used to combine the many samples taken along a ray into one value. Chapter 7, on an alternative rendering technique called volume slicing, is only four pages long. In this technique, a plane intersecting the volume is rendered instead of compositing values along rays. It is not clear whether this chapter was included as a historical review or as an optimization technique, since the same effect is possible with the more general ray casting method, albeit at a higher computational cost. Finally, chapter 8 deals with tradeoffs and optimization opportunities. This chapter suffers from the same lack of depth as do chapters 5 and 6. As soon as a topic gets interesting, the reader is reminded that this is only an introductory text by the brevity of the exposition.

The book is not as long as it seems. The eight chapters take up only 161 pages. The remaining 75 pages make up the appendix, glossary, references, and index. Also provided is a CD-ROM containing sample data sets and example programs. The code on the CD-ROM is written in a style that is easy to follow instead of being optimized for efficiency. I recommend that programmers reading the book follow along in the example programs. A tour of the code is not explicitly given in the text, but it is easy to make the association between concept and code snippet. Of particular interest to programmers is the 35-page appendix called “Volume Rendering Extensions for OpenGL.” This material, which is copyrighted by Hewlett-Packard, seems to be a proposal and not a final specification. The proposal fills in application programming interface details that are not mentioned in the text; for example, nonisotropic volumes must be scaled in each dimension to properly compute the gradient.

This work is an asset as a reference. The appendix and reference sections contain pointers to periodicals, organizations, Usenet newsgroups, Web sites, searchable databases, and public domain software, as well as references to 273 papers. Each chapter ends with a list of relevant references. I found this harder to follow than if the references had been placed directly in the text to which they related. However, the placement of all references for a chapter in their own section can turn the book into a tool for organizing a study of published papers in the field. For this use, I would recommend that readers tackle the references in the “For Further Study” sections of chapters 3 through 6 and tie them into the concepts presented in the chapter material.

I have some minor issues with the organization of the material. Why does the first chapter have a description of the file format used in the examples? That kind of detail, especially because it is not mentioned or used elsewhere, belongs in an appendix. The choice of print quality apparently dictated that all the images be printed in black and white. Unfortunately, most of the material relies heavily on the use of color to distinguish the relevant details. There are eight glossy pages in the center of the book on which the same images are reproduced in color. The fact that figures of rendered images had a reference to a color image at the center of the book (referred to as a plate) took a little getting used to.

All in all, this is an easy book to read. What it skimps on in technical depth it makes up in reference coverage.