| 摘要 |
PURPOSE:To reduce variance in a focusing time by obtaining three continuous positions where the contrast on the intermediate position is maximum within a range where the contrast is a threshold or above and aligning a position obtained by using the values of the contrast in the respective positions and executing a weighted average operation as a focusing position. CONSTITUTION:An image processing part 77 processes a signal from an image sensor 76 according to automatic focusing algorithm which is carried out and a placing table 71 placing an object 70 is driven through a placing table driving device 78 based on the processed result so as to execute automatic focusing. Namely, by detecting the movement and the contrast of the placing table 71, a position where the contrast is the threshold or above is searched and from the range where the contrast is the threshold or above, three positions where the contrast is near a peak value are obtained so as to decide the focusing position with the weighted average operation by using three positions. Thus, the focusing time can be shortened and focusing in which variance is small can be executed. |
