Low Cost Projector Mosaic
We have developed a set of techniques to create large format displays using casually installed overlapping projectors. The image alignment and intensity blending is completely automatic. The time required to calibrate the system is less than 20 seconds allowing a very easy to use and flexible setup. Current multi-projector systems cost several times the price of the projectors due to the expensive infrastructure and maintenance. Our techniques focus on software methods to reduce the cost by eliminating the need of rigid support structures and manual alignment.
Background & Objective: A photo-mosaic is a collection of images registered together to form one large image. Can we create a similar projector mosaic on a display surface by seamlessly merging output of overlapping projectors? For photo-mosaic, the images are captured by casually orienting and positioning the camera. Can we similarly create a large display using casually aligned projectors? Currently, large displays are generated by tiling together a two dimensional array of projectors by precisely aligning them. Due to such design constraints, the installation and operation of such systems is extremely expensive. If we allow casual approximate installation, the cost of multi-projector systems can be greatly reduced. Further, if the registration and blending of overlapping images is performed completely automatically, such systems can become very easy to use allowing wide spread use in homes, offices and shops.
Technical Discussion: We use a camera in the loop to automatically compute the relative projector pose. Our algorithms solve two fundamental problems involved in multi-projector displays. First, we achieve sub-pixel alignment between overlapping projectors by exploiting the homography induced due to the display plane. Second, we use a fast technique to find intensity feathering weights to cross-fade the projected images in the overlapping region. We use 3D graphics hardware to achieve real-time pre-warping of the images so that they generate a single seamless image when projected. The techniques can be used for rear-projector or front-projection display.
Contact: Joseph Katz
| Technical Reports: | |
| A Low-Cost Projector Mosaic with Fast Registration | |
Technology Areas:
Off the Desktop Interaction and Display
Computer Vision
Graphics
Modification Date: July 7, 2008
