Research Of Multi-Projector-Based Augmented Reality System

The goal of augmented reality is to create high level of consistency between real and virtual environments. Projector-based display is one of novel approaches in this research field. The advantage of projector is that it makes augmented reality applications more natural in interaction, and can generate images on any surface in theory. By increasing projectors, we can get almost unlimited visual range, arbitrary display resolution, and immersed user experience. As a result, such techniques become a hot research topic in augmented reality domain at present. Images from a multi-projector display must be seamless, providing the user with the illusion of a single display. So this involves correcting for geometric misalignment and color variation within and across the different projectors to create a final image that is both geometrically and photometrically seamless.After reviewing the related works, and considering the robustness and accessibility of system, this paper presents new camera-based geometric and color calibration algorithm. For geometric calibration, we propose a unified coordinate image transformation algorithm, and deal with two types of geometric distortion in one process. We project the checkerboard pattern, and capture by camera to get the geometric information feedback. The distortion of checkerboard pattern simulates the geometry of surface. By transform from the arbitrary surface problem to many little planar surface problems, we guarantee both the accuracy and the efficiency of geometric calibration. For color calibration, we combine the geometric blending with camera-based photometric uniformity of prior approaches after considering the human vision and projector property. Image correction is focused on luminance to achieve photometric uniformity. The calibration processes are simple, and produce a display on which imagery is undistorted for the human viewer. This method is robust and accurate, and can be implemented with commercial off-the-shelf components.Based on calibration algorithm, we replace the traditional graphic workstation with PC cluster system to implement our distributed multi-projector-based augmented reality system. Our system, after a one-time calibration procedure, can real-time render scene, as long as the environment does not change.This paper breaks through the restriction of display surface in traditional projector application. We improve the geometric and color calibration algorithm to ensure that our system can project seamless image on any arbitrary surface. This is just what the augmented reality requires and has positive research effects. We use the distributed architecture for application to meet the requirements of flexibility and scalability. We also consider the device cost and precision. Because of the accessibility and low cost, we believe that our method will make the multi-projector system more popular.