| 摘要 |
PURPOSE:To quickly focus a lens with a high precision in an infrared image pickup device by operating a focus detection signal for every picture element of one horizontal line. CONSTITUTION:Vertical scanning of two-dimensional scanning is temporarily stopped and only horizontal scanning is continued to stepwise move a lens related to focusing out of image forming lenses in the direction of the optical axis by every minute distance. With respect to a video signal Vj (i=1-N, N is the number of picture elements sampled in one horizontal scanning period) obtained by sampling the video signal due to horizontal scanning in one horizontal scanning period, a focus detection signal sj is calculated for every position (j) of the lens related to focusing in accordance with an operation formula in one horizontal period. Then, the lens related to focusing is displaced to the position where the focus detection signal Sj has a maximum value. |
