| 摘要 |
<p>A focus controller which is used for video cameras, etc., and has image pickup means (1 and 2) that pick up the image of an object through a focus lens and output electric signals corresponding to the object is provided with extracting means (621 and 631) which extract the high-frequency components of the electric signals outputted from the means (1 and 2), evaluation value generating means (62 and 63) which generate evaluation values representing the focused state of the object based on the high-frequency components outputted form the means (621 and 631), a storing means (66) which stores a plurality of evaluation values which change with the movement of the focus lens by correlating the values with the positions of the lens so as to find the just-focus position of the lens, a selecting means which selects a plurality of evaluation values used for finding the just-focus position from the evaluation values stored in the storing means (66), and a control means (4) which finds by calculation the just-focus position based on the evaluation values selected by the selecting means (4) and the positions of the lens corresponding to the selected evaluation values. Thus control of the focus of the focus lens with high accuracy is realized and the just focus is computed at high speed after the focus lens passes the just-focus position (focal position) only one time, even if noise is contained in evaluation values or noise is steadily contained in evaluation value when the luminance is low.</p> |
