| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-cost automatic focus controller which detects an accurate focusing position even when the luminance difference of a subject in striped pattern or cyclic pattern and performs stable focusing operation even for a subject including a high-luminance part without being affected by disturbance such as noise. SOLUTION: A CPU 8 outputs a lens control signal to a driving device 2 to move a lens 1 to an infinite-distance position and performs initial exposure to fetch image data of one frame. An integrating circuit 7 scans luminance Y data in the direction of a chord passing the center of the circle of a focus detection area on a screen to integrate differences in the value of luminance data Y between adjacent pixels and store them corresponding to the lens position (infinite-distance position). The CPU 8 while moving the lens 1, step by step, from the infinite-distance position to a shorter distance records the integral value in an internal memory at each position and judges whether the lens 1 reaches a near-distance limit position to repeat the movement until the near- distance limit position is reached. |
