AUTOMATIC FOCUS CONTROLLING METHOD OF AUTOMATIC FOCUSING CAMERA

摘要

PURPOSE:To attain automatic focus control to any automatic focusing cameras having different kinds, constitutions, etc. by the same AF processing circuit by executing the automatic focus control on the basis of a camera output signal which is the final output of the camera part. CONSTITUTION:A synchronizing signal separating circuit 41 forms a necessary reference timing from a camera output signal and a control circuit 42 controls a line selecting circuit 43 on the basis of the timing and extracts a video signal in a prescribed range. Since the extracted video signal is formed by superposing a carrier to a luminance signal, only the luminance signal is separated and extracted by a luminance signal separating circuit 44 and sent to an automatic focus operating circuit 45. The circuit 45 calculates the frequency component of the luminance signal, and the control circuit 42 controls the driving of a motor 6 through a driving circuit 5 so that the high frequency component is maximized.