| 摘要 |
PURPOSE:To improve the S/N of a focus signal and suppress the maximal point, and to perform fast, high-accuracy focusing adjustment by adding the output amplitude value of the frequency component of an image signal and generating a focus signal, and filtering this signal. CONSTITUTION:An image picked up by a photographic optical system 31 is formed on a line sensor 32, whose image signal is passed through a BPF 37 to extract its specific frequency component. The output amplitude of the signal is detected by a detector 38 and divided by a divider 41 by the counted value of a counter 35, so that the signal is corrected to a value corresponding to the storage time. Then the value is added by an integration circuit 42 to output the focus signal. This signal is filtered by a filtering circuit 45 and inputted to a microprocessor 46 to calculate the focusing position. Then focusing adjustment is performed with a control signal based upon the focusing position. Consequently, the S/N is improved to suppress the maximal point, and the fast, high- accuracy focus adjustment is performed. |
