Patent ID: 7620311
Filing Date: 2009-11-17
Classification: G03B,H04N

Abstract:
1. An auto-focus apparatus comprising: an evaluation value calculator configured to periodically calculate evaluation values using high frequency components of image signals in a specific region of a subject image captured by an image-capture unit; a distance measurement unit configured to measure a distance to a subject and output a distance measurement result; a control unit configured to output instruction values provided to a lens driver for driving a focus lens based on the evaluation values and determining whether a subject image is in-focus or out-of-focus, using the evaluation values; and a storage configured to store distance measurement results and positions of the focus lens, wherein after the control unit operates to search the peak of the evaluation values while moving positions of the focus lens and detects the relative maximum of the evaluation values, the control unit returns the focus lens to the position corresponding to a point at which the relative maximum has been detected, obtains the evaluation values calculated by the evaluation value calculator, stores the focus position and distance measurement results when the evaluation values satisfy a prescribed condition, and retrieves the distance measurement results and focus positions when the number of times that the focus positions and distance measurement results are stored reaches a prescribed number, and computes a correction amount for distance measurement results output from the distance measurement unit based on a relation between the retrieved distance measurement results and focus positions.