Total recall: in-place viewing of captured whiteboard annotations

Total Recall introduces a new way to view captured whiteboard annotations. To digitize drawings we used a modified commercial system. However, instead of displaying the annotations on a separate computer screen, Total Recall shows the annotations at the place on the board where they were actually made. The user holds a hand-held computer to the board and moves it to reveal the desirable portion of the captured annotations. By using ultra-sonic positioning and optimized graphics, we achieve a high frame-rate (30 fps), allowing for very smooth panning and interaction. We argue that this way of viewing captured whiteboard annotations is more natural and intuitive than current desktop-based systems.