| 摘要 |
PURPOSE:To avoid the effect of a fluctuation component of a focus signal caused by noise or flicker onto the detection by implementing the discrimination of increase/decrease in a focal point signal and the discrimination of focusing through the comparison of a threshold level including the fluctuation component of focus signal with the mean data of focus signal. CONSTITUTION:An image pickup element (CCD) 14 receives a light 13 of an object made incident through a zoom lens 11 and a focus lens 12, a camera process circuit 15 processes the light as a video signal and the processed signal is generated and outputted as a luminance signal and a chrominance signal. An AF window circuit 16 extracts only a luminance signal in an area required for the focus automatic control and the result is inputted to a BPF 17 passing only a signal band required for the focus automatic control. A microcomputer 20 gives an integration clear signal CR to an integration device 19 at the start of one field and receives integration data FD at the end of one field. Furthermore, the microcomputer 20 outputs a lens drive signal AS for each field. A focal point signal (focal point voltage) is obtained through the repetition of the operation of the microcomputer 20. |
