| 摘要 |
PURPOSE:To provide a highly precise automatic focusing device capable of obtaining a defocusing amount D from an image deviation DELTA by using a linear approximation equation. CONSTITUTION:The calculation of a defocusing amount D is separately performed in every area by using linear approximation and the defocusing amount D is obtained from an image deviation DELTA. An area where the image deviation exists is judged. For example, when the image deviation exists in an area 3, the image deviation DELTA does not become negative until e1, e2 and e3 are subtracted. In a routine in an area 3, the defocusing amount D is obtained by adding e3, excessively subtracted, to the deviation, multiplying an amount in the area 3 by a gradient a3 in the area 3 and adding a defocusing amount B2 up to the area 2. When the image deviation DELTA is negative, their signs are opposite. By further multiplying the defocusing amount D by an coefficient L related to a lens, the defocusing amount D for actually moving the lens is obtained. |
