| 摘要 |
An automatic focusing system includes an active range finding system (11) and a passive range finding system (12). An initial measurement is made by the active range finding system (11). If the initial measurement indicates that the lens focus is within a predetermined scope, control of further focusing is transferred immediately to the passive range finding system (12). If this condition is not met initially, lens focusing begins based on data from the active range finding system (11). The difference between measured range and the distance at which the lens (23) is focused is monitored. When this difference falls below the predetermined scope, the range finding function is transferred to the passive range finding system (12). Also, the variance between the distance measured by the active range finding system (11) and the distance at which the lens (23) is focused is used to determine a degree of blur. If the degree of blur is less than a predetermined blur, the range finding function is transferred to the passive range finding system (12). In one embodiment, the active range finding system (11) employs a plurality of spaced-apart light emitters (13) that illuminate physically spaced-apart objects. <IMAGE> |
