A Scalable Distributed Paradigm for Multi-User Interaction with Tiled Rear Projection Display Walls

Abstract

Fig. 1. This figure shows some of our applications in action. From left to right: Our collaborative map visualization application with two users visualizing different parts of the map at the same time on our 3 × 3 array of nine projectors; Our collaborative emergency management application with two users trying to draw a path to hazardous location and dispatching teams of first responders on our 3 × 3 array of nine projectors; Digital graffiti drawn using our collaborative graffiti application on only six of the projectors. We deliberately did not edge blend the projectors to show the six projectors clearly; Four children working together on our digital graffiti application on a 3 × 3 array of nine projectors.Abstract-We present the first distributed paradigm for multiple users to interact simultaneously with large tiled rear projection display walls. Unlike earlier works, our paradigm allows easy scalability across different applications, interaction modalities, displays and users. The novelty of the design lies in its distributed nature allowing well-compartmented, application independent, and application specific modules. This enables adapting to different 2D applications and interaction modalities easily by changing a few application specific modules. We demonstrate four challenging 2D applications on a nine projector display to demonstrate the application scalability of our method: map visualization, virtual graffiti, virtual bulletin board and an emergency management system. We demonstrate the scalability of our method to multiple interaction modalities by showing both gesture-based and laser-based user interfaces. Finally, we improve earlier distributed methods to register multiple projectors. Previous works need multiple patterns to identify the neighbors, the configuration of the display and the registration across multiple projectors in logarithmic time with respect to the number of projectors in the display. We propose a new approach that achieves this using a single pattern based on specially augmented QR codes in constant time. Further, previous distributed registration algorithms are prone to large misregistrations. We propose a novel radially cascading geometric registration technique that yields significantly better accuracy. Thus, our improvements allow a significantly more efficient and accurate technique for distributed self-registration of multi-projector display walls.

A Distributed Memory Hierarchy and Data Management for Interactive Scene Navigation and Modification on Tiled Display Walls

“…Single static projector-camera unit, lighting a large static surface (either wall mounted or on top of a table), has been explored to create multi-user interactive displays [27,55]. The work by John Underkoffler on such a display formed by a network of projector camera systems [46]. Some systems have merged synthetic images with real scenarios for a static user or view point.…”

“…Therefore, we develop completely distributed methodologies for grouping Though the algorithm in [46] extends well to our scenario of multiple CDs, our collaborative SAR system is still significantly different than the system in [46] due to the following reasons. …”

“…Further, when any of its neighbors projects the white, it should be able to observe it through the larger field of view camera to detect the overlap, its shape and size. It assigns the overlap to be a left, right, top or bottom one (as is required by [46]) based on the largest number of pixels present in its four quadrants. it.…”

“…In [46] the registration is achieved by first presenting a QR code by each projector in their overlap region that encodes its IP address, port number, and ID into the QR code. Note that the overlaps are all trapezoidal due to keystoning and can be differently shaped and sized.…”

“…Second, a standard placement of QR codes as in [46] can overlap or conflict with the QR code from another ADN. So, we introduce two steps to alleviate this situation.…”