Augmented Reality AR is a growing area in virtual reality research. The world environment around us provides a wealth of information that is difficult to duplicate in a computer.
This is evidenced by the worlds used in virtual environments. Either these worlds are very simplistic such as the environments created for immersive entertainment and games, or the system that can create a more realistic environment has a million dollar price tag such as flight simulators.
An augmented reality system generates a composite view for the user. It is a combination of the real scene viewed by the user and a virtual scene generated by the computer that augments the scene with additional information. The application domains described in Section 1. In all those applications the augmented reality presented to the user enhances that person's performance in and perception of the world. The ultimate goal is to create a system such that the user can not tell the difference between the real world and the virtual augmentation of it.
To the user of this ultimate system it would appear that he is looking at a single real scene. Figure 1 shows a view that the user might Phd Thesis Augmented Reality from an augmented reality system in the medical domain. It depicts the merging and correct registration continue reading data from a pre-operative imaging study onto the patient's head. Providing this view to a surgeon in the operating theater would enhance their performance and possibly eliminate the need for any other calibration fixtures during the procedure.
Figure 1 - Simulated augmented reality medical image. Virtual reality is a technology that encompasses a broad spectrum of ideas. It defines an umbrella under which many researchers and companies express their work.
The phrase was originated by Jaron Lanier the founder of VPL Research click of the original companies selling virtual reality systems. The term was defined as "a computer generated, interactive, three-dimensional environment in which a person is immersed. First, this virtual environment is a computer generated three-dimensional scene which requires high performance computer graphics to provide an adequate level of realism.
The second point is that the virtual world is interactive. A user requires real-time response from the system to be able to interact with it in an effective manner.
The last read more is that the user is immersed in this virtual environment. One of the identifying marks of a virtual reality system is the head mounted display worn by users. These displays block out all the external world and present to the wearer a view that is under the complete control of the computer.
The user is completely immersed in an artificial world and becomes divorced from the real environment. For this immersion to appear realistic the virtual reality system must accurately sense how the user is moving and determine Phd Thesis Augmented Reality effect that will have on the scene being rendered in the head mounted display.
Will virtual and augmented reality move us into the knowledge age?
The discussion above highlights the similarities and differences between virtual reality and Phd Thesis Augmented Reality reality systems. A very visible difference between these two types of systems is the immersiveness of the system. Virtual reality strives Phd Thesis Augmented Reality a totally immersive environment.
The visual, and in some systems aural and proprioceptive, senses are under control of the system. In contrast, an click reality system is augmenting the real world scene necessitating that the user maintains a sense of presence in that world. The virtual images are merged with the real view to create the augmented display.
There must be a mechanism to combine the real and virtual that is not present in other virtual reality work. Developing the technology for merging the real and virtual image streams is an active research topic and is briefly described in Section 1.
The computer generated virtual objects must be accurately registered with the real world in all dimensions. Errors in this registration will prevent the user from seeing the real and virtual images as fused.
The correct registration must also be maintained while the user moves about within the real environment. Discrepancies or changes in the apparent registration will range from distracting which makes working with the augmented view more difficult, to physically disturbing for the user making the system completely unusable. An immersive virtual reality system must maintain registration so that changes in the rendered scene match with the perceptions of the user.
Any errors here are conflicts between the visual system and the kinesthetic or proprioceptive systems. The phenomenon of visual capture gives the vision system a stronger influence in our perception Welch This will allow a user to accept or adjust to a visual stimulus overriding the discrepancies with input from sensory systems.
In contrast, errors of misregistration in an augmented reality system are between two visual stimuli which we are trying to fuse to see as one scene. We are more sensitive to these errors Azuma ; Azuma Milgram Milgram and Kishino ; Milgram, Takemura et al. He defines the Reality-Virtuality continuum shown as Figure 2. Figure 2 - Milgram's Reality-Virtuality Continuum.
The real world and a totally virtual environment are at the two ends of this continuum with the middle region called Mixed Reality. Augmented reality lies near the real world end of the line with the predominate perception being the real world augmented by computer generated data.
Augmented virtuality is a term created by Milgram to identify systems which are mostly synthetic with some real world imagery added such as texture mapping video onto virtual objects.
This is a distinction that will fade as the technology improves and the virtual elements in the scene become less distinguishable from the real ones. Milgram further defines a taxonomy for the Mixed Reality displays.
The three axes he suggests for categorizing these systems are: Reproduction Fidelity relates to the quality of the computer generated imagery ranging from simple wireframe approximations to complete photorealistic renderings.
The real-time Phd Thesis Augmented Reality on augmented reality systems forces them to be toward the low end on the Reproduction Fidelity spectrum. The current graphics hardware capabilities can not produce real-time photorealistic renderings read more the virtual scene. Milgram also places augmented reality systems on the low end of the Extent of Presence Metaphor. This axis measures the source of immersion of the user within the displayed scene.
This categorization is closely related to the display technology used by the system. There are several classes of displays Phd Thesis Augmented Reality in augmented reality systems that are discussed in Section 1. Each of these gives a different sense of immersion in the display. In an augmented reality system, this can be misleading because with some display technologies part of the "display" is the user's direct view of the real world.
Click in that display comes from simply having your eyes open. It is contrasted to systems where the merged view is presented to the user on a separate monitor for what is sometimes called a "Window on the World" view. Augmented reality does not simply mean the superimposition of a graphic object over a real world scene.
This is technically an easy task. One difficulty in augmenting reality, as Phd Thesis Augmented Reality here, is the need to maintain accurate registration of the virtual objects with the real world image.
As will be described in Section 1. In some domains these relationships are well known which makes the task of augmenting reality easier or might lead the system designer to use a completely virtual environment. The contribution of this thesis will be to minimize the calibration and world knowledge necessary to create an augmented view of the real environment.
Only recently have the capabilities of real-time Phd Thesis Augmented Reality image processing, computer graphic systems and new display technologies converged to make possible the display of a virtual graphical image correctly registered with a view of the 3D environment surrounding the user.
Researchers working with augmented reality systems have proposed them as solutions in many domains. The areas that have been discussed range from entertainment to military training. Many of the domains, such as medical Rosen, Laub et al. This section will highlight some of the proposed applications for augmented reality.
Because imaging technology is so pervasive throughout the medical field, it is not surprising Phd Thesis Augmented Reality this domain is viewed as one of the more important for augmented reality systems.
Most of the medical applications deal with image Popular Dissertation Site surgery. Pre-operative imaging studies, such as CT or MRI scans, of the patient provide the surgeon with the necessary view of the internal anatomy. From these images the surgery is planned.
Visualization of the path through the anatomy to the affected area where, for example, a tumor must be removed is done by first creating a 3D model from the multiple views Phd Thesis Augmented Reality slices in the preoperative study.
This is most often done mentally though some systems will create 3D volume visualizations from the image study. Augmented reality can be applied so that the surgical team can see the CT or MRI data correctly registered on the patient in the operating theater while the procedure is progressing. Being able to accurately register the images at this point will enhance the performance of the surgical team and eliminate the need for the painful and cumbersome stereotactic frames shown in Figure 3 that are currently used for registration.
Figure 3 - Typical Stereotactic Frames from Mellor Other work in the area of image guided surgery using augmented reality can be found in Lorensen, Cline et al.
Interactive 3D Modelling in Outdoor Augmented Reality Worlds A Research Thesis for the Degree of the Doctor of Philosophy. By Wayne Piekarski. Visual Tracking for Augmented Reality Georg Klein King’s College A thesis submitted for the degree of Doctor of Philosophy January Find A PhD. Search Funded PhD Projects, Programs & Scholarships in Augmented Reality. Search for PhD funding, scholarships & studentships in the UK, Europe and around. business plan help alberta Phd Thesis Augmented Reality how to write an application letter topics to write research papers on. PhD Guidance in Augmented Reality providing all stages of research recommendations globally for PhD research scholars. We offer complete support.
Another application for augmented reality in the medical domain is in ultrasound imaging State, Chen et al. Using an optical see-through display the ultrasound technician can view a volumetric rendered image of the fetus overlaid on the abdomen of the pregnant woman. The image appears as if it were inside of the abdomen and is correctly rendered as the user moves. Information about this prototype system can be found in Brooks A simple form of augmented reality has been in use Phd Thesis Augmented Reality the entertainment and news business for quite some time.
Whenever you are watching the evening weather report the weather reporter is shown standing in front of changing weather maps.
In the studio the reporter is actually standing in front of a blue or green screen. This real image is augmented with computer generated maps using a technique called chroma-keying. It is Phd Thesis Augmented Reality possible to create a virtual studio environment so that the actors can appear to be positioned in a studio with computer generated decorating.
Examples of using this technique can be found at Schmidt ; Schmidt b. Movie special effects make use of digital compositing to create illusions Pyros and Goren Strictly speaking with current technology this may not be considered augmented reality because it is not generated in real-time.
Most special effects are created off-line, frame by frame with a substantial amount of user interaction and computer graphics system rendering. But some work is progressing in computer analysis of the live action images to determine the camera parameters and use this to drive the generation of the virtual graphics objects to be merged Zorpette