ABSTRACT
We present an installation that allows distributed internet participants to “draw” on a public scene using light. The iLight system is a camera/projector system designed for remote collaboration. Using a familiar digital drawing interface, remote users “draw” on a live video image of a real-life object or scene. Graphics drawn by the user are then projected onto the scene, where they are visible in the camera image. Because camera distortions are corrected and the video is aligned with the image canvas, drawn graphics appear exactly where desired. Thus the remote users may harmlessly mark a physical object to serve their own their artistic and/or expressive needs. We also describe how local participants may interact with remote users through the projected images. Besides the intrinsic “neat factor” of action at a distance, this installation serves as an experiment in how multiple users from different locales and cultures can create a social space that interacts with a physical one, as well as raising issues of free expression in a non-destructive context.
Keywords camera/projector systems, augmented reality, annotation, remote collaboration
Categories and Subject Descriptors H.5.3 [Information Interfaces and Presentation]: Group and Organization Interfaces – Synchronous interaction; H.5.1 [Information Interfaces and Presentation]: Information Systems – Artificial, augmented, and virtual realities
General Terms Algorithms, Human Factors
1. INTRODUCTION
Light [1] is a camera-projector system that allows a user to draw on a video image of a real-world scene using digital Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Figure 1: iLight system architecture ink1. The drawn marks are projected onto the scene, and are visible to the drawer through the video image, as well as to anyone in the vicinity of the projector. The iLight system thus allows a remote user to draw on real-world objects using an active video interface. Because the iLight drawing tools are web enabled, participants around the world will be able to draw on a real-world object such as a New York City sidewalk.
1.1 User Experience
The system has two classes of viewers: local and remote. Local users see the projected images, and possibly interact with them (see Section 1.3. Remote users have a richer set of possibilities: they may passively view the projected images, or they can add to or alter the images using text and drawing tools in the iLight palette. Though the drawing tools are fairly rudimentary (at least by comparison with professional image creation software) they are easy to use and don’t necessarily hinder creativity. For example, the image in Figure 3 was created with similarly limited drawing tools by an anonymous user. Because multiple remote users will access the same virtual canvas, they may interact with each other both creatively and destructively. Note that there is no practical way to monitor and/or censor the projected images. If access is unrestricted, this may result in potentially offensive text or drawings being projected. However, any remote user also has the ability to erase or comment on anything projected, so it is likely that truly offensive content will be short-lived. This tension is an inherent part of the installation.


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