| 摘要 |
PURPOSE: To reduce the amt. of data necessary to correct the nonuniformity of a signal train outputted from a pair of photoelectric conversion element trains. CONSTITUTION: The difference amount between a true correction factor applied to a focus detector and for removing the nonuniformity of output signal from an image sensor array 2 for a uniform luminance surface and a predicted correction factor theoretically calculated based on an optical design value is previously stored. A balance value concerning the turbulence of balance between a pair of signal trains caused by the effect of a half mirror is stored and further a pair of signal trains is divided into plural areas so as to calculate the offset value of the difference amount for every divided area. A value obtained by dividing the offset value by a compressibility factor and the compressibility factor are previously stored so that the offset value may be equal to or under a specified number of bits. A nonuniformity correction circuit 3 calculates the final defocusing amount based on the predicted correction factor, the difference amount, the balance value and the offset value. |
