Focus adjustment device, imaging device and focus adjustment method
AssigneeElmo Co., Ltd.
InventorMasaaki Toguchi
Life of this patent
Estimating the term…
Abstract
A video camera constructed according to one aspect of the focus adjustment device moves a focus lens forward and backward and detects peak values of an AF evaluation value of the focus lens in the forward moving direction and in the backward moving direction. The video camera calculates a correction value based on a difference between the peak value of the evaluation value detected in the forward motion of the lens and the peak value of the evaluation value detected in the backward motion of the lens. The video camera corrects the AF evaluation value with the calculated correction value and detects a focused position of the lens based on the corrected AF evaluation value in moving the lens.
Claims8
A focus adjustment device that moves a lens in a direction of an optical axis to adjust a focus of the lens, the focus adjustment device comprising:
- an evaluation unit configured to analyze an image captured via the lens and specify an evaluation value representing a focused state of the lens;
- a correction value calculation unit configured to capture an image of a specific subject with moving the lens forward and backward, and calculate an evaluation correction value for correcting the evaluation value, based on a difference between a peak value of the evaluation value detected in a forward motion of the lens and a peak value of the evaluation value detected in a backward motion of the lens, prior to moving the lens for adjustment of the focus;
- a focused position detection unit configured to correct the evaluation value with the calculated evaluation correction value according to a moving direction of the lens, and detect a focused position of the lens, based on the corrected evaluation value in moving the lens for adjustment of the focus;
- and
- a focusing control unit configured to move the lens to the detected focused position.
An imaging device that moves a lens in a direction of an optical axis to adjust a focus of the lens, the imaging device comprising:
- an evaluation unit configured to analyze an image captured via the lens and specify an evaluation value representing a focused state of the lens;
- a correction value calculation unit configured to capture an image of a specific subject with moving the lens forward and backward, and calculate an evaluation correction value for correcting the evaluation value, based on a difference between a peak value of the evaluation value detected in a forward motion of the lens and a peak value of the evaluation value detected in a backward motion of the lens, prior to moving the lens for adjustment of the focus;
- a focused position detection unit configured to correct the evaluation value with the calculated evaluation correction value according to a moving direction of the lens, and detect a focused position of the lens, based on the corrected evaluation value in moving the lens for adjustment of the focus;
- a focusing control unit configured to move the lens to the detected focused position;
- and
- an imaging unit configured to capture the image via the focused lens.
A focus adjustment method that moves a lens in a direction of an optical axis to adjust a focus of the lens, the focus adjustment method comprising:
- analyzing an image captured via the lens and specifying an evaluation value representing a focused state of the lens;
- capturing an image of a specific subject with moving the lens forward and backward, and calculating an evaluation correction value for correcting the evaluation value, based on a difference between a peak value of the evaluation value detected in a forward motion of the lens and a peak value of the evaluation value detected in a backward motion of the lens, prior to moving the lens for adjustment of the focus;
- correcting the evaluation value with the calculated evaluation correction value according to a moving direction of the lens, and detecting a focused position of the lens, based on the corrected evaluation value in moving the lens for adjustment of the focus;
- and
- moving the lens to the detected focused position.
Dependencies are inferred from the claim text.