Tele-Graffiti is a system allowing two or more users to communicate remotely via hand-drawn sketches. What one person writes at one site is captured using a video camera, transmitted to the other site(s), and displayed there using an LCD projector.

With Tele-Graffiti, the users write on regular pieces of paper that are tracked in real-time by the system. See the following movie for a demonstration of (1) the system hardware, (2) the Tele-Graffiti tracking algorithm, and (3) two users interacting using Tele-Graffiti.

Image shows video sequence.

We have also built a hand-based user interface and an automatic session summarization feature for Tele-Graffiti. Both of these features, as well as the basic system operation, are demonstrated in the following movie.

Image shows video sequence.

We have also analyzed the Tele-Graffiti feedback loop and derived a model for the Tele-Graffiti image formation process. We used this model to derive the final viewed image and the optimal gain with which to set up the system to optimize the image quality. We also derived an algorithm to separate the final viewed images into the two actually drawn components (without imaging them directly). Two examples of this process are shown below.

and

See the unofficial webpage for more details.