| 摘要 |
<p>A device for detection of self-movement has an optically convergent interface (24) and a substantially linear marker (34). Means (28) is provided to relatively position the convergent interface (24) and linear marker (34) so that the marker extends away from the convergent interface on the same side as the focus or focal line thereof, at least to a positon (P) at which the virtual image of the linear marker (34) is significantly further displaced from the convergent interface than is the position (P) in real space. The device can be used by sportsmen such as golfers to detect body sway during the execution of a stroke.</p> |
