Week 2 summaries
Merging Virtual Objects with the Real World: Seeing Ultrasound Imagery within the Patient
The paper describes the research work on ultrasound imagery within human body.
It starts from a brief review of previous research about 3D ultrasound, which is a relatively safe method compared with other imaging techniques. Ultrasound performs much better in real-time data acquisition than imaging. And its shortcomings are high noise ratio and poor spatial resolution.
3D data acquisition is based on the incremental method in which hundreds of 2D slices are combined to reconstruct a volume. A system developed in Philips Paris Research Laboratory is introduced, which uses some mechanical ways to scan images from different angles. 3D data display can be presented by either image display or set values.
Later the authors introduced their incremental volume visualization in details. In their 4D convolution process, time stamps are assigned to each constantly updated 3D voxel. Some incremental algorithm is used to render the final images based on the collected data.
When applying the ultrasound technique to real human body, there can be some problems, such as conflicting visual cues, system latency, stability and resolution.
Virtual Environments for Treating the Fear of Heights
This paper is about acrophobia treatment, which is a typical application of VR techniques. In background section, some preliminary results like Kaiser-Permanente’s work and Japanese sand-play project are mentioned. While related documentations are still limited in quantity.
In this acrophobia treatment project, experimenters focus on the extent to which subjects feel they are in height situation, as well as the effects of the treatment method. They conducted a lot of graphics work on designing virtual height situation, that is, elevator, balconies and bridges.
More than 400 students were asked to answer the questionnaires, some of which participate the offered entry into the study. They were assigned into different group to conduct a control experiment. The questionnaires are used to evaluate the effects of the method. They did some statistical analysis on different variables to test the efficacy.
The rationales of the experiment are to activate the fear structure in virtual height situation and help people with acrophobia to attenuate their anxiety, which is quantized as subjective unit of discomfort ratings. Participants’ comments and symptoms are also treated as important qualitative data.
The final result shows that all negative attitudes toward heights decreased significantly for the treatment group. And the authors conclude that virtual reality exposure can have wide applicability.
Designing Interactive Theme Park Rides
This paper is really interesting. What’s more important is, it is easy to read. It tells us a story about an interactive ride, named Pirates of the Caribbean, in theme parks. Pirates is a game where guests act as pirates to explore on the high sea and fight against many kinds of monsters and ghosts.
The most exciting positions in this game are several islands. So the designers come up with some ideas to attract guests to go there. Architectural weenies, guide ships, sneak attacks and water spout contribute to this setting.
Compared with reality, designers concentrate more on guests’ experience. Guests play this game in 4-person group sailing a boat and operating cannons to attack enemies. The game will end in two ways: defeat Jolly Roger or be defeated. Designers carefully work on the latter ending to compensate the feeling of losing a game.
Designers trade off a lot between reality and virtual reality. They consider that as a multi-player game, Pirates should provide more experiences on movement and interaction. Both the steering wheel and cannons are physical, adding to the sense of reality. And the fact that nobody goes to theme parks alone will guarantee a big success.
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