VIRTUAL REALITY
[ Home ] [ Up ] [ LESSON 1 ] [ LESSON 2 ]

LESSON 1 - INTRODUCTION

    The term VIRTUAL REALITY, or VR, has recently come into widespread use; however, what this term actually means can vary widely with who is using it. Most often it is used to mean a computer-generated "world" or non-real background setting, usually immersive to the senses, and often with interactive features. Frequently, the term "cyberspace" is used interchangeably with virtual reality. Cyberspace, as noted in the text, has been defined as "The place where you are when you’re on the phone." (John Perry Barlow, Technology reporter and lyricist for the Grateful Dead.)

We have all seen or heard of examples of virtual reality systems. Usually, we see a person wearing a type of helmet covering his eyes. This helmet is actually a viewing device which displays a three dimensional picture of some computer-generated scene. The user may be wearing a type of glove connected so that when he moves his hand a computer generated hand will move in the picture he is viewing. He reaches forward into nothing and closes his hand about thin air. In the view in the helmet the hand grasps a box on a table and moves it to another location. These systems exist now and are used in a wide variety of applications.

In Japan , when you wish to select a floor plan in order to have a house constructed, instead of looking at floor plans you can view a computer-generated picture of the house as seen by someone walking through it. Using a joystick you can turn and look around you, move from room to room, open drawers or turn on the water in the sink. If you find, for example, the drawer in which you keep your pot holders can’t be opened at the same time as the oven, you can request a change in design before the house is constructed. Such conditions may be very hard for an untrained lepers to discover from a set of blueprints but can be easily found in the computer "walk through."

In another system a player may sit in a small booth which includes visual and audio displays and "fight" a tank battle with another player in a similar booth.

A pilot learns to fly a new type of aircraft using a flight simulator. Advanced simulators include not only visual displays showing realistic views, but also audio and motion devices to provide a realistic "flight" experience. In one such simulator - the Air Force’s Super Cockpit - an experienced pilot made an error causing the simulator to "crash." The effect was so realistic that he passed out.

These systems exist. The ones being developed go far beyond this and, for example, allow an operator sitting in a room in Texas to operate a mining vehicle on the moon. Or a doctor in Boston can observe and direct a delicate operation taking place in Kansas. All of these systems involve extensive computer use and high tech display and control devices. They are what we usually think of when we speak of "virtual reality."

Actually, the term includes far more than this.

A "virtual" reality means a set of sensory sensations which conveys to the recipient a feeling of being in, seeing, feeling, etc., the set of circumstances portrayed by these sensations. This is a complicated way of saying that some sight (or sound or smell or ...) makes you feel you are in some other place. One of the earliest examples of this is the cave painting.

Paintings from the caves at LASCAUX, France.

                           http://www.edf.fr/html/en/mag/histoire/cosques.htm                                                                                                

    While cave paintings are not usually thought of as VR, their purpose was to make the viewer "see" the animal shown. They also demonstrate one important idea about VR "worlds": The depiction does not have to exactly match the scene being conveyed. A cave drawing might not look exactly like a real antelope; however, the image of the real animal is invoked in the mind of the viewer. This happens because the image acts as a trigger to bring forth scenes already familiar to the viewer and stored in his mind. Many of today’s complicated, computer-generated, virtual worlds utilize this same principle: Represent something with which the viewer is already familiar and do so in a simplified fashion.

One note: In this class the term "view" will often be used to indicate use of any one or a combination of the senses. Thus when someone "views" a virtual world he may be seeing, hearing, smelling, or feeling or a combination of any of these. The word "view" is used because it is the most common sense invoked and provides a very high level of information compared to the others.

VARIATIONS OF REALITIES

A number of classifications, or variations, of realities exit. This may seem like a strange statement, but it will make much more sense when examined.

1. RECORDED REALITY. First there is a realistic presentation of a recorded REAL world. For example, the pilot in the simulator may view film of actual views taken from a real aircraft. He sees the same sights as he would in an actual aircraft flying the same course. This RECORDED REALITY contains the most detail. It is not necessary for the viewer to be familiar with the subject (as was required for the cave painting). However, the viewer must still have a common knowledge base. That is, if he has no idea what a road will look like from 30,000 feet, the recording may still not mean anything to him. Fortunately, humans are very adaptable and can project what a road might look like from 30,000 feet even if they have never flown; however, to do this they still must know what a road looks like from some distance to be able to extrapolate.

A variation of the RECORDED REALITY is a TRANSPOSED REALITY. This might be a view seen by the surgeon in Boston as he looks at a video picture taken by a camera mounted on the head of the doctor in Kansas actually performing an operation. The view he is seeing actually exists, but in a different location. The reason this is a variation of the RECORDED REALITY can be seen if you think of the recorded view as simply a real view transposed in time instead of (or in addition to) being transposed in space. We often refer to a reality transposed in space as Telepresence, because the viewer is "present" in the other location by means of some form of telecommunication.

2. SIMULATED REALITY. Sometimes a view is simulated, or produced, to depict a real setting but without using a recording of this setting. In this case an effort is still made to depict the scene exactly as a real viewer would see it. Only the common knowledge base and not the familiarity with the actual scene is needed by the viewer. One such example of this would be a movie set in which a real location is "created" using miniatures or even detailed computer drawn pictures. In the movie STAR TREK II, the forested planet used as background and location for some of the action did not exist outside of a computer memory. To the viewer, however, the scenes could have been filmed in some national park location.

3. REPRESENTED REALITY. In this type of virtual world an effort is made to recreate something with which the viewer is familiar. It is desired to create the feeling of actually being in the depicted location; however, to simplify the requirements of computer power and memory, compromises are made and detail is left out. This is the type of representation used in the house tour described above. Often line drawings or wire frame outlines are used to create a recognizable picture of the house and fixtures within. There is no way a viewer would mistake such a drawing for an actual photograph, but because the viewer is familiar with the subject matter, the simple representation evokes a more detailed picture in the viewer’s mind. The same principle was used in the cave paintings.

4. NON-REAL REALITIES. All of the above realities depict some scene or action which might actually exist in the real world we know. It is also possible to generate a world or action which could not exist in our real world. For example, we might produce a view inside the cylinder of an internal combustion engine in which the viewer can walk about and observe the engine operation as it takes place. Obviously, because of the size difference and the temperatures and pressures encountered in a real engine, a human could not walk about inside. However, in our generated reality this is possible. This is an example of a "REAL" NON-REAL REALITY. By this we mean that the scene of the engine may be completely realistic and accurately represent the internal view of an engine. The movements of the human observer may also be realistically represented. The combination, however, of both of these in the same place and time is non-real.

We can also create SYMBOLIC NON-REAL REALITIES. One program allows a stock broker to view the current, real-time activity of hundreds of stocks. The stocks are represented as columns. The colors and the height of these columns change to indicate activity: changes in price, sales volume, etc. This is certainly a non-real world: stocks are NOT colored columns. What we have done is construct symbols to represent events and actions which are real but which do not appear in the real world in any form resembling our symbols.

5. AUGMENTED REALITY. In the case of an augmented reality, a world is created in which scenes of the real world are mixed with additional creations, such as representations of other real items or non-real symbols. An example of such a system is the "Heads-Up Display", or HUD, used on aircraft. In such a system the pilot views the real world through the windshield of the aircraft. Additionally, information is projected onto the windshield by a computer. For example, the pilot might see a superimposed bright orange path representing the desired approach to an airport along side a series of numbers giving his altitude and distance to touchdown. Or if the aircraft is approaching an airport in the dark, an infrared picture may be projected onto the windshield to aid in landing.

As you can see, a virtual world may range from actual views (and sounds, smells, etc.) or a real scene to purely abstract or symbolic creations. It can alter our perception of space, size, proportion, or time. It can contain only created images or a combination of real time sense input and computer-generated sense input.

TYPES OF VIRTUAL REALITY

Virtual Reality worlds may be grouped into two classifications depending upon the effects their viewers can exert upon the world. They may be classified as either PASSIVE or INTERACTIVE.

PASSIVE. In a passive VR world, the viewer can observe and experience, but he cannot alter it. A common example is a typical movie. The viewer may become very immersed, or lost, in the world of the movie, its locations and actions. But no matter how real this appears to the viewer, he can have absolutely no effect on the outcome. Such worlds can provide sense inputs to any of the senses to increase the realism of the experience. We have seen a number of moves in this direction in the history of movies. Color was added. Sound provided another sense. Stereo sound can convey the effect of motion. The use of surround sound takes this one step farther. Curved screens (or even surrounding screens) can add to the effect of really "being there". Cinerama movies used three cameras and three projectors to provide a wide picture on a curved screen. Stereo sound was used to enhance the effect. One of the early Cinerama movies opened with a view through the window of the door of an aircraft several thousand feet up. This was shown with a single projector on the center screen. Shortly into the movie, the aircraft door was opened. Simultaneously, the other two projectors were turned on and the sound volume was increased, giving a very realistic effect of standing in the door. When I saw this movie, an additional effect was added, whether by design or accident I don’t know. When the door was opened, the theater air conditioning also came on at a high level, providing a notable increase in cold air. All such sense inputs increase the feeling of being "in" the virtual world, even though the viewer cannot affect his virtual surroundings.

INTERACTIVE. In interactive virtual worlds the viewer can interact with his virtual surroundings. In the house tour described above the viewer could open a drawer or change his speed or direction through the house. This is the type of system we usually think of when we mention Virtual Reality. Here, the viewer not only can observe a created world but can cause things to happen in it, change the scene by moving objects, or even affect the action.

The degree to which the user can interact with the virtual world can vary widely from one system to another. The interaction can be either single or multi-sense. For example, in a house tour you open a drawer. In one system you may move your hand and see the drawer open. In another, more advanced, system you not only see the virtual hand open the drawer, but you also feel the touch of the virtual drawer on your real hand. Obviously, such a system would require much more complex design than a single sense system.

Whether a system allows interaction with only one or multiple senses, the capabilities of interaction (degrees of action) can also vary. Using the house tour as an example again, one system may allow you to control the speed at which you move through the house but require that you follow a predetermined route. Another may allow changes in route: go in one room one trip, a different one next time. A more advanced system might allow not only changes in speed of walking and variations of route, but might also allow you to alter the viewing angle and look around in different directions. One system might allow you to open drawers, another to move objects from one location to another. The more degrees of action, the more complicated the system.

A system can also be more interactive if it provides feedback. In just walking through the house and opening the virtual drawer, the only feedback provided will likely be visual: You see the drawer open. If a proper type of control glove or other device is provided, it can also be possible to "feel" the drawer when you grasp it and pull it open. Such systems with tactile feedback can greatly enhance the feeling of reality of the system, but require complex hardware and extensive computer capabilities.