| 摘要 |
PROBLEM TO BE SOLVED: To obtain an auto-focus camera which detects a correct focal point even when an imaging signal is saturated. SOLUTION: While shifting a focus lens from an infinite end to a closest range by driving a motor 13, a CPU 12 obtains an integrated value of an imaging signal in a frequency band 1 removing the low frequency components from an imaging signal picked up by an imaging device 2 through a band-pass filter 9, and an integrated value of the imaging signal in a frequency band 3 not removing the low-frequency components, correspondingly to a plurality of the respective lens positions. The CPU 12 obtains a focal point evaluation value in each frequency band by using these integrated values. Further, when regarding a maximum evaluation value as saturated, the CPU 12 calculates a new evaluation value parameter 1 history by subtracting a focal point evaluation value history in the frequency band 1 from a focal point evaluation value history in the frequency band 3 , and determines an extreme value of the new evaluation value parameter 1 history by three-point interpolation operation, and thus calculates a lens position D1 (New) corresponding to the extreme value. COPYRIGHT: (C)2004,JPO&NCIPI |
