FOCUS DETECTING APPARATUS, LENS APPARATUS INCLUDING THE SAME, IMAGE PICKUP APPARATUS, AND METHOD OF DETECTING DEFOCUS AMOUNT

摘要

A focus detector, which detects a defocus amount from a displacement amount between images formed by a pair of light beams split from an image pickup system so as to pass through a pair of pupil regions, includes a pair of lenses and phase difference sensors, a memory unit for storing an image displacement amount between the image signals on the phase difference sensors in an in-focus state, a waveform read out controller for setting pixels to be calculated for the phase difference sensors, respectively, based on the image displacement amount, a correlation calculator for calculating a correlation amount between the image signals from the pixels to be calculated, a waveform degree-of-conformity calculator for calculating a waveform degree-of-conformity based on the image signals obtained from the pixels to be calculated, and a defocus calculator for calculating the defocus amount based on the correlation amount and the waveform degree-of-conformity.

主权项

1. A focus detecting apparatus for detecting a defocus amount of an image pickup optical system based on a displacement amount between a pair of images formed by a pair of light beams split from the image pickup optical system so as to pass through a pair of pupil regions, the focus detecting apparatus comprising:
a pair of lenses; a pair of phase difference detecting sensors for photoelectrically converting a pair of object images formed by the pair of lenses into a pair of image signals; a memory unit for storing an image displacement amount, which is an imaging position displacement in a longitudinal direction of the pair of phase difference detecting sensors, between the pair of image signals obtained by the pair of phase difference detecting sensors when the image pickup optical system focuses on a predetermined object; a waveform read out controller for setting pixels to be calculated for the pair of phase difference detecting sensors, respectively, based on the image displacement amount stored in the memory unit; a correlation calculator for calculating a correlation amount between the pair of image signals obtained from the pixels to be calculated of the pair of phase difference detecting sensors; a waveform degree-of-conformity calculator for calculating a waveform degree-of-conformity that is a degree-of-conformity between the pair of image signals based on the pair of image signals obtained from the pixels to be calculated of the pair of phase difference detecting sensors; and a defocus amount calculator for calculating the defocus amount based on the correlation amount calculated by the correlation calculator and the waveform degree-of-conformity calculated by the waveform degree-of-conformity calculator.