There are several ways of building a remote sketching system. One way is to use a tablet and a stylus to input the sketch, and a computer monitor to display the sketch at the remote site. Such systems have a number of disadvantages. Writing with a stylus on a glass tablet is unnatural compared to sketching with a regular pen and paper. Shading and other effects are harder to achieve. Changing color means using the computer to select a new color. Incorporating existing hard-copy documents such as a graded exam is impossible.
Another way of building a remote sketching system is to use a video camera to image the sketch at one end, transmit the captured video to the other end, and displays it there using an LCD projector. See Figure 1 for a schematic diagram of how such a system might operate. The first such camera-projector based remote sketching system was Pierre Wellner’s Xerox “Double Digital Desk”Recommend this topic