Introduction

Definition

What is Augmented Reality? In general it is every technique which extents the reality with some virtual effects. It can be thought of as somewhere between completely real and Virtual Environment[8]. Fig. 1-1 shows the relationships of real, augmented and virtual. But this includes many things. For example this definition includes the computer generated visual effects in movies. In common the AR is seen like in Ronald Azuma's ``A Survey of Augmented Reality''[3]. AR systems have to follow three characteristics:

1. Combines real and virtual
2. Interactive in real time
3. Registered in 3-D

Most implementations of AR use some sort of tracker (see section 2) with 6 degrees of freedom and a HMD (head mounted display). But this definition does not insist on an HMD.

Figure 1: Simplified representation of an Reality-Virtuality Continuum

Motivation

Augmented Reality is very interesting because combining real and virtual worlds enhances user's perception. Enhancing the perception can also enhance its interaction with the real world. This helps to perform real-world task faster and better. Some examples are shown in the next section.

Research on AR is a challenge. There are many things to improve and to find out. Accurate tracking, the display and the user-interface are the greatest problems at the moment. The EMMIE project[4] of the Columbia university for example addresses the user-interface-problem. EMMIE is a hybrid user interface combining a variety of different technologies and techniques, including virtual elements, and physical objects such as tracked displays and input devices. The prototype includes additional 2D and 3D displays, ranging from palm-size to wall-size, allowing the most appropriate one to be used for any task.

Examples

Annotation

Information that is helpful is added to the real world. One example is Steven Feiner's prototype that helps navigating through the campus of the Columbia university[6]. In museums additional information to the objects would be very useful.

Entertainment

Games and interactive TV are only two areas where AR could be used. And it's much cheaper to make virtual objects than physical ones. AR makes it possible to create completely new types of games.

Manufacturing and Repair

HMDs could help the technicians if they have to handle very complex machines. This could save a lot of time. Boeing for example is working at this area.

Medical

The doctor can look at the real patient and additional data can be shown. Or the doctor can see inside the patient before the operation. And two doctors on different locations could work on one virtual body.

Military

The soldiers can walk through unknown terrain, and the correct path is shown in a HMD. Or data as height and speed are shown the pilot of an aircraft.

Robot path planning

The user manipulates a virtual robot whose actions are added to the real world, and thus can be verified.