Focus detection apparatus, control method for the same, and image capture apparatus

An image capture apparatus comprising:

• an image sensor in which a first pixel, and second pixel, and an imaging pixel are arranged, the first pixel receiving light flux that is restricted to light flux passing through a first portion of a pupil area of an imaging optical system, the second pixel receiving light flux that is restricted to light flux passing through a second portion that is different from the first portion of the pupil area, and the imaging pixel being different from the first and second pixels;
• one or more processors;
• and
• a memory storing instructions which, when executed by the one or more processors, cause the image capture apparatus to function as:
• a focus detection apparatus that comprises an acquisition unit an estimation unit, and a focus detection unit;
• and
• an adjustment unit that adjusts a focal point of the imaging optical system based on the defocus amount detected by the focus detection apparatus, wherein:
• the acquisition unit acquires signals of pixels from an image sensor in which a first pixel, a second pixel, and an imaging pixel are arranged, the first pixel receiving light flux that is restricted to light flux passing through a first portion of a pupil area of an imaging optical system, the second pixel receiving light flux that is restricted to light flux passing through a second portion that is different from the first portion of the pupil area, and the imaging pixel being different from the first and second pixels;
• the estimation unit estimates, based on the acquired signals, a first estimated signal corresponding to the first pixel at a position at which the first pixel is not arranged, and a second estimated signal corresponding to the second pixel at a position at which the second pixel is not arranged;
• and
• the focus detection unit calculates a defocus amount of the imaging optical system based on a first signal constituted by the first estimated signal and the signal from the first pixel, and a second signal constituted by the second estimated signal and the signal from the second pixel.

A method for controlling a focus detection apparatus, the method comprising:

• an acquisition step of acquiring signals of pixels from an image sensor in which a first pixel, a second pixel, and an imaging pixel are arranged, the first pixel receiving light flux that is restricted to light flux passing through a first portion of a pupil area of an imaging optical system, the second pixel receiving light flux that is restricted to light flux passing through a second portion that is different from the first portion of the pupil area, and the imaging pixel being different from the first and second pixels;
• an estimation step of, based on the acquired signals, estimating a first estimated signal corresponding to the first pixel at a position at which the first pixel is not arranged, and a second estimated signal corresponding to the second pixel at a position at which the second pixel is not arranged;
• and
• a focus detection step of calculating a defocus amount of the imaging optical system based on a first signal constituted by the first estimated signal and the signal from the first pixel, and a second signal constituted by the second estimated signal and the signal from the second pixel.