| 摘要 |
PURPOSE:To attain high-accuracy focusing point detection by using a low-frequency component as to an area to be extracted from video signal areas for detection, and varying the detection level. CONSTITUTION:A monitor circuit 3 calculates the detection level, the moving speed of an optical path length verying member 101, etc., with the video signal outputted by a photoelectric converting element 102. Then while the optical path length varying member 101 is moved by a driving circuit 105, a frequency detecting circuit 104 extracts the low-frequency component as to the area specified by a processing circuit 106 and detects and amplifies the frequency component according to the detection level as a reference. Namely, the mean values of the outputs of sensors which constitute the photoelectric converting element 102 is calculated and used as the detection level for the detection, and further amplified to obtain definition information, which is used to calculate a frequency power value. Consequently, the ability to detecting a focusing point can be improved and the highly accurate focusing point detection is attained. |
