| 摘要 |
PURPOSE:To accurately detect the focus independently of the contrast of an object by providing plural monitor elements arranged near one image forming part, a monitor circuit which detects the luminance and the contrast of the object, and a differential amplifying circuit which subtracts a prescribed DC luminance component from a picture signal in accordance with the luminance and the contract and amplifies the result and a prescribed amplification factor. CONSTITUTION:When the output voltage of a monitor element M2 whose output is highest reaches a reference voltage, a storage stop signal is outputted from a monitor circuit 13 to a microcomputer 10 and a shift signal is outputted from the microcomputer 10 to a CCD (charge coupled device) driver 7 and the CCD driver 7 outputs a shift pulse to a CCD 5 to shift the stored electric charge to a shift register and outputs it as the picture signal to a differential amplifier 14. A dark output component is subtracted from the picture signal inputted to the differential amplifier 14 and a prescribed DC luminance component is subtracted from it, and the result is amplified with a prescribed amplifier factor. Thus, the in-focus position is accuracy detected. |
