# US 10,375,294 B2 · Focus detection apparatus and focus detection method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,375,294 B2 - Document ID: US10375294B2 - Status: Granted - Kind: B2 - Application number: 15/847,792 - Filed: 2017-12-19 - Published: 2018-06-21 - Granted: 2019-08-06 - Earliest claimed: 2016-12-21 - Assignees: Olympus Corporation - Applicants: Olympus Corporation - Inventors: Tetsuo Kikuchi; Koichi Shintani - Web page: https://patentgrep.com/patent/US10375294B2 ## CPC - H04N 23/67: Focus control based on electronic image sensor signals - H04N 23/63: by using electronic viewfinders - H04N 23/672: {based on the phase difference signals} - H04N 23/675: {comprising setting of focusing regions} - H04N 23/687: {by shifting the lens or sensor position} - H04N 23/71: Circuitry for evaluating the brightness variation - H04N 23/72: Combination of two or more compensation controls - H04N 23/73: by influencing the exposure time - H04N 25/704: Pixels specially adapted for focusing, e.g. phase difference pixel sets - H04N 23/663: for controlling interchangeable camera parts based on electronic image sensor signals - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A focus detection apparatus includes an imaging element includes that a plurality of focus detection pixels, a correction value calculation unit that calculates a correction value used to correct pixel signals based on an optical state before the imaging element performs imaging for still image capturing or imaging for focus detection, a correction unit that performs correction using the correction value simultaneously with reading the pixel signals from the focus detection pixels subsequent to the imaging for the still image capturing or the imaging for the focus detection by the imaging element, and a focus detection unit that performs focus detection based on the corrected pixel signals. ## Claims ### Claim 1 A focus detection apparatus comprising: an image sensor that includes a plurality of focus detection pixels and that images a subject via an imaging optical system; a correction value calculation circuit that calculates a correction value based on an optical state, the correction value being used to correct pixel signals output from the focus detection pixels, the optical state being associated with light fluxes from the subject incident on the focus detection pixels; a luminance correction circuit that corrects the pixel signals output from the focus detection pixels using the correction value; and a focus detection circuit that performs focus detection based on the corrected pixel signals, wherein the luminance correction circuit calculates, when imaging for still image capturing is performed in a continuous-exposure mode, the correction value based on the optical state during driving of a focus lens and an aperture immediately before the imaging for still image capturing by the image sensor, and calculates, when imaging for focus detection is performed in the continuous-exposure mode, the correction value based on the optical state during reading of the pixel signals acquired in a previous imaging for still image capturing, and the correction value calculation circuit performs the correction using the correction value simultaneously with the reading of the pixel signals from the focus detection pixels subsequent to the imaging for the still image capturing and the imaging for the focus detection. ### Claim 2 (depends on 1) The focus detection apparatus according to claim 1, wherein the optical state corresponds to a state of an aperture value in the imaging for the still image capturing, and the correction value calculation circuit calculates the correction value based on the aperture value. ### Claim 3 (depends on 2) The focus detection apparatus according to claim 2, further comprising an exposure control circuit that calculates an exposure setting value including the aperture value, the aperture value being used in the imaging for the still image capturing based on pixel signals acquired by imaging for still image capturing prior to current still image capturing, during reading of pixel signals acquired by imaging for the current still image capturing. ### Claim 4 (depends on 1) The focus detection apparatus according to claim 1, wherein the optical state corresponds to an amount of movement of the imaging optical system or the image sensor in camera shake correction, when the camera shake correction moves the imaging optical system or the image sensor, and the correction value calculation circuit calculates the correction value based on an amount of movement of the imaging optical system or the image sensor during initialization of the camera shake correction. ### Claim 5 (depends on 4) The focus detection apparatus according to claim 4, wherein the correction value calculation circuit calculates the correction value, the correction value is used in imaging for focus detection performed subsequently to imaging for current still image capturing, based on the amount of movement of the imaging optical system or the image sensor during the initialization. ### Claim 6 (depends on 1) The focus detection apparatus of claim 1 wherein the continuous-exposure mode includes repeatedly performing a sequence of still imaging, auto-focus imaging, live view display imaging. ### Claim 7 (depends on 6) The focus detection apparatus of claim 6 wherein the continuous-exposure mode further includes repeatedly performing focus lens and aperture driving after the auto-focus imaging. ### Claim 8 A focus detection method comprising: causing an image sensor that includes a plurality of focus detection pixels to image a subject via an imaging optical system; calculating a correction value based on an optical state, the correction value being used to correct pixel signals output from the focus detection pixels, the optical state being associated with light fluxes from the subject incident on the focus detection pixels; correcting the pixel signals output from the focus detection pixels using the correction value; and performing focus detection based on the corrected pixel signals, wherein the calculating of the correction value includes calculating, when imaging for still image capturing is performed in a continuous-exposure mode, the correction value based on the optical state during driving of a focus lens and an aperture immediately before imaging for still image capturing by the image sensor, and calculates, when imaging for focus detection is performed in the continuous-exposure mode, the correction value based on the optical state during reading of the pixel signals acquired in a previous imaging for still image capturing, and the correcting includes performing the correction using the correction value simultaneously with the reading of the pixel signals from the focus detection pixels subsequent to the imaging for the still image capturing and the imaging for the focus detection by the image sensor. ### Claim 9 (depends on 8) The focus detection method of claim 8 wherein the continuous-exposure mode includes repeatedly performing a sequence of still imaging, auto-focus imaging, live view display imaging. ### Claim 10 (depends on 9) The focus detection method of claim 9 wherein the continuous-exposure mode further includes repeatedly performing focus lens and aperture driving after the auto-focus imaging.