Automatic focusing apparatus with cyclic pattern determination

摘要

An automatic focusing apparatus includes a position detecting unit for a focus unit, a driving unit for the focus unit, a focus detecting unit using a phase difference method, a contrast acquiring unit for picking up an image of object, and a focusing determining unit based on a contrast, a cyclic pattern determining unit for an object based on focus information obtained by the focusing detecting unit, a target position setting unit for driving of the focus unit, and a focusing direction determining unit, and, when the object has a cyclic pattern, the apparatus determines a direction of an in-focus point, sets a target position in the determined direction of the in-focus point, drives the focus unit toward the target position, and determines whether or not in-focus state is achieved by using the focusing determining unit.

主权项

1. An automatic focusing apparatus, comprising:
an image pickup optical system including a focus lens unit; a focus position detector for detecting a position of the focus lens unit; a focus driving unit for driving the focus lens unit; an image pickup unit for picking up an image of an object through use of a beam having passed through the image pickup optical system; a focus detecting unit for detecting focus information by a phase difference method through use of the beam from the object; a contrast acquiring unit for acquiring a contrast evaluating value using an image pickup signal obtained by the image pickup unit; a focusing determining unit for determining whether or not an in-focus state is achieved based on the contrast evaluating value; a cyclic pattern determining unit for determining whether or not the object has a cyclic pattern based on the focus information provided by the focus detecting unit; a target position setting unit for setting a target position for driving of the focus lens unit; and a focusing direction determining unit for determining a direction of focusing, wherein, when the cyclic pattern determining unit determines that the object has the cyclic pattern, the focusing direction determining unit determines the direction of focusing, the target position setting unit sets the target position of the focus lens unit to any one of a plurality of focusing proposed positions based on detection by the focus detecting unit in the direction of focusing, the focus driving unit drives the focus lens unit toward the target position, and the focusing determining unit determines whether or not the in-focus state is achieved, and wherein the target position setting unit switches between an operation in which the target position is set at one of multiple focusing proposed positions based on the detection of the focus detecting unit and an operation in which the target position is set at an end in the direction of focusing, based on the contrast evaluating value at a position of the focus lens unit and the contrast evaluating value at a position different from the position of the focus lens unit.