| 摘要 |
<p>The apparatus includes alignment means (13, 14) for determining the direction of a sight-line (12) extending from an observer (11) to a display surface (10), projection means (15, 16) for projecting an image of a graticule into the sight-line for movement therewith, and control means (17) operable to cause the display of a movable cursor on the display surface (10) when the sight-line (12) intersects the display surface.</p> |
