Virtual Reality Technology

Grigore C. Burdea, Philippe Coiffet

• Verlag: Wiley-IEEE Press
• Jahr: 2017
• ISBN:
  9781119485728
• Auflage: 2
• Thema: Computer Science
• Thema: Virtual Reality

A groundbreaking Virtual Reality textbook is now even better Virtual reality is a very powerful and compelling computer application by which humans can interface and interact with computer-generated environments in a way that mimics real life and engages all the senses. Although its most widely known application is in the entertainment industry, the real promise of virtual reality lies in such fields as medicine, engineering, oil exploration and the military, to name just a few. Through virtual reality scientists can triple the rate of oil discovery, pilots can dogfight numerically-superior "bandits, " and surgeons can improve their skills on virtual (rather than real) patients. This Second Edition of the first comprehensive technical book on the subject of virtual reality provides updated and expanded coverage of the technology--where it originated, how it has evolved, and where it is going. The authors cover all of the latest innovations and applications that are making virtual reality more important than ever before, including:
* Coverage on input and output interfaces including touch and force feedback
* Computing architecture (with emphasis on the rendering pipeline and task distribution)
* Object modeling (including physical and behavioral aspects)
* Programming for virtual reality
* An in-depth look at human factors issues, user performance, and
* sensorial conflict aspects of VR
* Traditional and emerging VR applications
The new edition of Virtual Reality Technology is specifically designed for use as a textbook. Thus it includes definitions, review questions, and a Laboratory Manual with homework and programming assignments. The accompanying CD-ROM also contains video clips that reinforce the topics covered in the textbook. The Second Edition will serve as a state-of-the-art resource for both graduate and undergraduate students in engineering, computer science, and other disciplines. GRIGORE C. BURDEA is a professor at Rutgers-the State University of New Jersey, and author of the book Force and Touch Feedback for Virtual Reality, also published by Wiley. PHILIPPE COIFFET is a Director of Research at CNRS (French National Scientific Research Center) and Member of the National Academy of Technologies of France. He authored 20 books on Robotics and VR translated into several languages.

CHAPTER 1
INTRODUCTION

The scientific community has been working in the field of virtual reality (VR) for decades, having recognized it as a very powerful human–computer interface. A large number of publications, TV shows, and conferences have described virtual reality in various and (sometimes) inconsistent ways. This has led to confusion, even in the technical literature.

Before we attempt to define virtual reality, we should first say what it is not. Some researchers refer to telepresence, in which a user is immersed in a remote environment. This is very useful in telerobotics [Sheridan, 1992], where we attempt to control robots at a distance and where knowledge of what is happening around the robot is critical. Others have used the name enhanced reality or augmented reality (AR) [Müller, 1999], where certain computer graphics, or text, is overlaid on top of real images. A technician attempting to repair an installation may look at a photo in which overlaid graphics makes apparent otherwise occluded components [Bejczy, 1993]. Both telepresence and augmented reality incorporate images that are real, so neither is virtual reality in its strictest sense.

Technologists have been joined by artists and journalists in trying to define the field. The cover of the book The World of Virtual Reality published in Japan [Hattori, 1991] depicts Alice in the Wonderland, as shown in Figure 1.1. This is more eye-catching and amusing than scientific. Others have referred to virtual reality in terms of the devices it uses and not its purpose and function. The general public tends to associate virtual reality simulations with head-mounted displays (sometimes called “goggles”) and sensing gloves, just because these were the first devices used in simulation. This is not a good definition either. Virtual reality today is done mostly without head-mounted displays, by using large projection screens or desk-top PCs [Robertson et al., 1993]. Similarly, gloves can be replaced with much simpler trackballs or joysticks [Schmult and Jebens, 1993]. Conversely, sensing gloves can be used in other tasks than VR, such as in telerobotics [Clark et al., 1989]. Therefore describing virtual reality in terms of the devices it uses is also not an adequate definition.

Fig. 1.1 The cover of The World of Virtual Reality.

From Hattori [1991]. Reprinted by permission.

Then what is virtual reality? Let us first describe it in terms of functionality. It is a simulation in which computer graphics is used to create a realistic-looking world. Moreover, the synthetic world is not static, but responds to the user’s input (gesture, verbal command, etc.). This defines a key feature of virtual reality, which is real-time interactivity. Here real time means that the computer is able to detect a user’s input and modify the virtual world instantaneously. People like to see things change on the screen in response to their commands and become captivated by the simulation. Anybody who doubts the spell-binding power of interactive graphics has only to look at children playing video games. It was reported that two youngsters in the United Kingdom continued to play Nintendo even though their house was on fire!

Interactivity and its captivating power contributes to the feeling of immersion, of being part of the action on the screen, that the user experiences. But virtual reality pushes this even further by using all human sensorial channels. Indeed, users not only see and manipulate graphic objects on the screen, they also touch and feel them [Burdea, 1996]. Researchers are also talking of the senses of smell and taste, although these sensorial modalities are less used at this time. In summary we give the following definition:

Definition Virtual reality is a high-end user–computer interface that involves real-time simulation and interactions through multiple sensorial channels. These sensorial modalities are visual, auditory, tactile, smell, and taste.

Virtual reality can also be described from the simulation content point of view as unifying realistic (or veridical [Codella et al., 1993]) realities with artificial reality. This is a synthetic environment, for which there is no real counterpart (or antecedent) [Krueger, 1991]. For the rest of this book we use the term virtual reality to encompass all the other terminology described earlier.

1.1 THE THREE I’S OF VIRTUAL REALITY

It is clear from the foregoing description that virtual reality is both interactive and immersive. These features are the two I’s that most people are familiar with. There is, however, a third feature of virtual reality that fewer people are aware of. Virtual reality is not just a medium or a high-end user interface, it also has applications that involve solutions to real problems in engineering, medicine, the military, etc. These applications are designed by virtual reality developers. The extent to which an application is able to solve a particular problem, that is, the extent to which a simulation performs well, depends therefore very much on the human imagination, the third “I” of VR. Virtual reality is therefore an integrated trio of immersion–interaction–imagination, as shown in Figure 1.2. The imagination part of VR refers also to the mind’s capacity to perceive nonexistent things. The triangle in Figure 1.2, for example, is easily “seen” by the reader, yet it only exists in his or her imagination.

1.2 A SHORT HISTORY OF EARLY VIRTUAL REALITY

Virtual reality is not a new invention, but dates back more than 40 years. In 1962, U.S. Patent #3,050,870 was issued to Morton Heilig for his invention entitled Sensorama Simulator, which was the first virtual reality video arcade. As shown in Figure 1.3, this early virtual reality workstation had three-dimensional (3D) video feedback (obtained with a pair of side-by-side 35-mm cameras), motion, color, stereo sound, aromas, wind effects (using small fans placed near the user’s head), and a seat that vibrated. It was thus possible to simulate a motorcycle ride through New York, where the “rider” sensed the wind and felt the pot-holes of the road as the seat vibrated. The rider could even smell food when passing by a store.

Fig. 1.2 The three I’s of virtual reality, immersion–interaction–imagination.

Adapted from Burdea [1993]. Reprinted by permission.

Heilig also realized the possibilities of head-mounted television. He designed a simulation mask that included 3D slides with wide peripheral effects, focusing controls and optics, stereophonic sound, and the capability to include smell. A depiction from U.S. Patent #2,955,156 issued to him on October 4, 1960, is shown in Figure 1.4. Heilig, a cinematographer by profession, was well ahead of his time. Like Jules Verne, he imagined a new machine that would replace the classical cinematographic experience of today. He was also like Thomas Edison, an inventor who not only dreamed ideas, but also transformed them into real machines. At the time of Heilig’s inventions, nobody realized the revolutionary technological progress they represented.

Heilig’s initial work on head-mounted displays (HMD) was continued by Ivan Sutherland. In 1966 Sutherland used two cathode ray tubes (CRTs) mounted along the user’s ears. Today’...