| 摘要 |
<p>Positional data, such as an outline of graphics on a page (1) is captured by following the outline with a stylus (4) to which are attached two inextensible lines (2a) each spooled at its other end within a housing (2) fixed in position in relation to the outline. As the stylus moves, the length of line unspooled or respooled is recorded and stored. This data can be converted into Cartesian coordinates for screen display. The housing typically contains step-up gearing to drive a slotted or apertured disc as the line respools or respools so that light pulses can be created and sensed through the rotating disc, and used as a digitised computer input for storage. More than two lines, and/or other non-physical links (RF, infrared, ultrasonic), and/or different measurement systems can be used.</p> |
