Enhancing Remote Walkthrough for E-learning Environments on Mobile Devices over Heterogeneous Networks

With the growth of the Internet and availability of high bandwidth connections to domestic users, it became possible to deploy remote navigation within virtual environments over the Internet. For instance, virtual museum walkthrough, virtual mall, gaming, training, monitoring, and e-learning, just to name a few. We have also seen a new trend towards wireless networks and the use of mobile devices with wireless communication capabilities. Specially, e-learning environments can benefit from remote exploration of virtual environments over wireless networks in order to provide users with rich 3D content such as virtual laboratories and remote visits where users can interact with the 3D e-learning system using mobile devices such as PDAs, cellphones, or laptops. However, the characteristics of wireless channels pose significant problems to real-time interactive multimedia applications. Wireless bandwidth is always changing and the communication channel is highly susceptible to error. In this paper, we focus on the design of a remote walkthrough within realistic virtual environments over heterogeneous networks for mobile devices. We propose a real-time system that deals with the acquisition or remote geometry rendering, compression, packetization and transmission of images, which serve as input to an image-based rendering technique for fast creation of new views on the mobile client device. The objective is to contribute with a solution for remote walkthrough over wireless networks, while guaranteeing a good image quality and navigation at acceptable frame rates on thin client devices. Simulation experiments show that our design has low frame rate fluctuation, which is important in order to guarantee stable image quality