[week2 summaries]
Virtual environments for treating the fear of heights
This paper mainly talks about using VE to help acrophobia patients to overcome the fear of heights. Acrophobia, according to wiki, is an extreme or irrational fear of heights. By setting up a virtual environment and expose those patients to the virtual height situations, the patients is expected to habituate.
In order to setting up the stage, firstly a graphics workstations was designed with numbers of virtual heights situation. The real-time response was set to 10-fps with detailed monoscopic images. To better observe and analysis the patients’ reaction, 3 virtual environments were created. They were an elevator with only waist high guard rail, a series of balconies which stretched outside a building and 3 canyon bridges varying in hight and steadiness.
Then, according to the American Psychiatric Association’s diagnostic and statistical manual and fear questionnaire specifically for this study, appropriate subjects were selected and randomly assigned to either a treatment group or a control group. A pre-treatment assessment was conducted for both group and after 7 weeks, a similar post-treatment assessment took place as comparison.
During therapy sessions, subjects would be asked every 5 minutes to evaluate their feelings in several related aspects. This was conducted by an advanced clinical psychology graduate student and the whole session was videotaped to be reviewed by a supervising licensed psychologist.
According to theory, the way to cure acrophobia is to activate the fear memory and modify it. Using virtual height situation for immersion was aimed at activation the memory for reconstruction. For acrophobia, the anxiety usually increases with higher exposure and decreases if time is spent in the situation. In virtual height environment, same reaction had be detected as evidence for the performance effect.
After therapy session, a table with PRE and POST assessment for both groups had shown the significant decrease of passive emotion in treatment group but not the other. Furthermore, some subjects reported progress in real life after the session, which evidences the session to be meaningful. The noticeable change showed the success in using VE to activate and modify negative attitudes toward height.
Merging Virtual Objects with the Real World: Seeing Ultrasound Imagery within the Patient
This paper described a system which can display ultrasound echography in real time. By doing that, there were two aspects we need to dig into: 3D volume data acquisition and 3D volume data display. The research here mainly concentrated on 3D volume data display.
The standard volume rendering techniques is not well suited in this case. This techniques relies on preprocessing while data we acquire is dynamic and needs to be rendered in real time. A incremental, interactive 3D ultrasound visualization technique is introduced to solve this problem. Firstly, they irregularly sample points from the targets. Since the targets is updating over time, the sampled points keep changing. Time stamps are used to mark different sample source. Then, the technique reconstructs a 3D volume based on the samples in corresponding time frame. So each time frame will get a unique 3D volume with incremental time steps. At last, a reconstructed 3D volume is rendered based on those time-specific 3D volumes.
To visualize the ultrasound image in place where the image is acquired, a system is developed to facilitate. The system has 3 components: image-acquisition and tracking; image-generation and a HMD. Firstly the ultrasound images are acquired by the scanners for later rendering. Simultaneously, HMD is taking a real-world image. The tracking system will track the position and orientation information both of the scanners and the HMD for calibration. After the ultrasound images get rendered based on the geometry provided by HMD, using rigid body rotation, a video mixed image is generated and sent to a VPL EyePhone (attached to the HMD) for display.
At the end, an experiment result of scanning the abdomen of a pregnant woman is shown and some remaining technical problems are listed for future research.
Designing Interactive Theme Park Rides
This paper mainly talks about how they designed the interactive game Pirates and what should be paid extra attention to when designing it.
As a interactive game which gives the guests freedom to explore, it doesn’t mean we can set them as a puma at large. The designer carefully placed some guidance (like architectural weenies, guide ships) or push (like sneak attacks or the waterspout) to keep or force the guests inside the game play area. Also, the architectural weenies, guide ships and sneak attack ship, by carefully design, together with scenario attached islands, will keep a balanced pacing between action and calm. Furthermore, the climax at the last 30 seconds is triggered for an ultimate battle between guests and Jolly Roger the Ghost Pirate. The open ended storyline will lends to a desire for a second round. In all, though looks like the players get the total freedom for destiny, the adventure pacing is actually under control to guarantee the fun.
Usability is another elements that impacts an interactive games’ quality. Pirates utilizes quite intuitive user interfaces: a steering wheel to steer and actual cannons to fire. To make it more handy, once on board, guests can play around with those facilities to acclimate. Apart from these physical fun, the game designers bend reality into a more show-like way, which gives the guests a fancy and breath-taking visual effect.
To make it more realistic, the designers mixed the motions (like cannon ball hit) and acoustic effect together, thus gamers can better immerse into the environment.
At last, a successful game is always designed and planned to satisfy people’s psychological needs. Noticing nobody goes to a theme park alone and people in small groups has the intention of enjoying shared experiences, a game like Pirates can always bring the participants tons of joy to share in between.
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