| 摘要 |
<p>An iris camera for capturing an image of an iris of a user comprises a lens, 123,131, and an image sensor 126,132, for capturing an image produced by the lens. A processor 136 analyses the degree of focus of successive images produced by the sensor and controls a lens position adjustment motor to move the lens to a position where a subsequent captured image potentially has an increased degree of focus. A proximity sensor 129 provides an initial measurement of the distance between the lens and the user. The processor is arranged to user the initial distance measurement obtained by the proximity sensor as a starting point for capturing images of the iris to effect a fine-focus adjustment.</p> |
