| 摘要 |
PROBLEM TO BE SOLVED: To realize an autofocusing device efficiently and accurately detecting a focal point by evading futile autofocusing operation. SOLUTION: At the autofocusing device, the contrast curve 96C1 of a video signal is firstly obtained by performing rough focusing operation at a scanning range from a point (a) to the point (b). When a differenceΔbetween the maximum value and the minimum value of a curve is small further operation is stopped by judging as the position of the focal point is drastically deviated, and only in the other case, the contrast curve 96C2 is obtained by performing the rough focusing operation at the scanning operation from the point a1 to the point (a) again. When a peak value P1 appears at the center part of the curve, close focusing operation is continuously performed at the scanning range from the point d1 to the point e1, so that the contrast curve 97C2 is obtained. When the difference Q2 between the peak value and the minimum value of the curve is small, a device discriminates that the focal point is not detected. In reverse case the device discriminates that the focal point F2 is detected at the position of a peak point P2. |
