The Design Of Collaborative Augmented Reality And The Consistency Maintenance Technique

Augmented Reality (AR) merges the virtual object or other additional information generated by computer into the user's view of the real world. In addition, the Collaborative AR (CAR) makes multiple participants to work together collaboratively. Now most of the CAR systems are local CAR systems which require all users in the system in a common environment. So the local CAR systems have many defects. This paper presents a sensor-based CAR experiment system. In order to avoiding the defects of the vision based registration, a view point adjustment method, which leverages sensors, is used in the system to solve the problem of registration and tracking, and the method makes the system more reliable. Experiment results show that the system can provide good real-time interactivity.Consistency maintenance is a kernel problem in the CAR system. This paper present two threads to solve the problem: local-lag and local-lag with echo.Choosing a proper lag value is a key problem in local-lag mechanism. This paper studies the effects of lag value. Experiment results indicate that the effect of lag value on task performance is not linear. Lag has no effect on task performance while ranging from 0 ms to 100 ms. From 100 ms to 500 ms, lag slightly affects task performance. Lag deteriorates task performance seriously while ranging from 500 ms to 600 ms. When lag is larger than 600 ms, the task can't be accomplished sometimes.Local-lag mechanism sacrifices some responsiveness of the system and leads to the deterioration of task performance, especially when lag is large. This paper proposes an echo method to improve the task performance. The echo method shows some system information to subjects to help subjects to control objects. Experiment results show that the echo method does improve the task performance. The results also give support to the guideline that properly showing some system information will increase the usability of the system.