US 10,095,004 B2Granted

Imaging apparatus and focusing control method

AssigneeFUJIFILM Corporation

InventorHitoshi Sakurabu

Life of this patent

Estimating the term…

Loading patent…

Abstract

Provided is an imaging apparatus capable of performing AF with a high precision regardless of an object while realizing increase in AF speed. When there is an AF instruction, photographing is performed while a focus lens is moved. AF evaluated values are calculated at every position of the focus lens by a contrast AF processing unit. The contrast AF processing unit calculates a sharpness in the vicinity of the maximal point of an evaluated value curve from three AF evaluated values, including the maximum value among calculated AF evaluated values and AF evaluated values calculated at positions in front and rear of a focus lens position corresponding to the maximum value, and position information of the focus lens corresponding thereto, and calculates a focusing position by a calculation method selected from among plural kinds of methods according to the sharpness.

Claims11

Dependent claims

An imaging apparatus comprising:

a focus lens configured to be movable in an optical axis direction;
an imaging element configured to image an object via the focus lens;
an evaluated value calculation unit configured to calculate an evaluated value for focusing using a picked-up image signal obtained through imaging by the imaging element at every position of the focus lens while moving the focus lens;
a sharpness calculation unit configured to calculate a sharpness in a vicinity of a maximal point of an evaluated value curve, which represents relationship between a position of the focus lens and the evaluated value, using at least three evaluated values calculated by the evaluated value calculation unit and position information of the focus lens corresponding to each of the at least three evaluated values;
a focusing position calculation unit configured to select, according to at least the sharpness calculated by the sharpness calculation unit, one of plural kinds of calculation methods using the at least three evaluated values and the position information of the focus lens corresponding to each of the at least three evaluated values, and to calculate the position of the focus lens corresponding to the maximal point of the evaluated value curve as a focusing position using the selected calculation method;
a focusing control unit configured to perform a focusing control to move the focus lens to the focusing position;
and
at least one processor configured to function as the evaluated value calculation unit, the sharpness calculation unit, the focusing position calculation unit, and the focusing control unit.

5 more elements

A focusing control method by an imaging apparatus having an imaging element configured to perform imaging of an object via a focus lens that is movable in an optical axis direction, the focusing control method comprising:

an evaluated value calculation step of calculating an evaluated value for focusing using a picked-up image signal obtained through imaging by the imaging element at every position of the focus lens while moving the focus lens;
a sharpness calculation step of calculating a sharpness in a vicinity of a maximal point of an evaluated value curve, which represents relationship between a position of the focus lens and the evaluated value, using at least three evaluated values calculated by the evaluated value calculation step and position information of the focus lens corresponding to each of the at least three evaluated values;
a focusing position calculation step of selecting, according to at least the sharpness calculated by the sharpness calculation unit, one of plural kinds of calculation methods using the at least three evaluated values and the position information of the focus lens corresponding to each of the at least three evaluated values, and calculating the position of the focus lens corresponding to the maximal point of the evaluated value curve as a focusing position using the selected calculation method;
and
a focusing control step of performing a focusing control to move the focus lens to the focusing position.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/614,216Filed 5 Jun 2017 · continuation
Priority: JP 2013-02686214 Feb 2013
Published: US 2017/0269326 A121 Sep 2017
Granted: 9 Oct 2018
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G02B 7/38
Using image sharpness techniques , e.g. image processing techniques for generating autofocus signals: measured at different points on the optical…
G03B 13/36
Power focusing: autofocus systems
H04N 23/673
Focus control based on electronic image sensor signals: based on contrast or high frequency components of image signals, e.g. hill climbing method
H04N 23/71
Circuitry for compensating brightness variation in the scene: circuitry for evaluating the brightness variation

Family

PCT/JP2013/079888Parent of this continuation · filed 5 Nov 2013
Application14/825,678Parent of this continuation · filed 13 Aug 2015
US 2017/0269326 A1Pre-grant publication · published 21 Sep 2017
US 9,703,070 B2Parent of this continuation
US 2015/0346585 A1Published application
US 10,095,004 B2This patent

From the US filing history. Foreign family members aren’t listed.