US 9,854,178 B2Granted

Image pickup apparatus with flicker detection and having plurality of unit pixel areas, control method therefor, and storage medium

AssigneeCanon Kabushiki Kaisha

InventorHidenori Taniguchi

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Abstract

An image pickup apparatus which is capable of calculating light amount changing characteristics of an object with high accuracy and enlarging a dynamic range during photometric measurement. An image pickup device of the image pickup apparatus has a plurality of unit pixel areas arranged in a two-dimensional matrix, and a first pixel and a second pixel are included in each of the unit pixel areas. When a flicker detection mode in which an image signal for use in calculating the light amount changing characteristics of the object is obtained is selected, a first accumulation period and a second accumulation period for the first pixels and the second pixels, respectively, are set such that a first barycentric position which is a barycentric position of the first accumulation period and a second barycentric position which is a barycentric position of the second accumulation period correspond to each other.

Claims12

Dependent claims

An image pickup apparatus comprising:

an image pickup device configured to have a plurality of unit pixel areas arranged in a two-dimensional matrix;
a setting unit configured to set electric charge accumulation periods for a plurality of first pixels and a plurality of second pixels included in the plurality of unit pixel areas as a first accumulation period and a second accumulation period, respectively;
and
a mode selection unit configured to select a first mode in which an image signal for use in detecting flicker of light is obtained, or a second mode in which an image signal for use in detecting an object brightness is obtained,
wherein when the mode selection unit selects the first mode, the setting unit sets the first accumulation period and the second accumulation period such that a first barycentric position which is a barycentric position of the first accumulation period for the plurality of first pixels included in the plurality of unit pixel areas and a second barycentric position which is a barycentric position of the second accumulation period for the plurality of second pixels included in the plurality of unit pixel areas correspond to each other,
wherein when the mode selection unit selects the second mode after the flicker of light is detected in the first mode, the setting unit sets the first accumulation period and the second accumulation period based on light amount changing characteristics of the flicker of light detected in the first mode,
wherein when the mode selection unit selects the second mode without the flicker of light being detected in the first mode, the setting unit sets the first accumulation period and the second accumulation period independently of light amount changing characteristics of the flicker of light,
wherein the first accumulation period and the second accumulation period at least partially overlap each other, and
wherein in the second mode, the first accumulation period is different in length of time from the second accumulation period.

6 more elements

A control method for an image pickup apparatus which has an image pickup device having a plurality of unit pixel areas arranged in a two-dimensional matrix and obtains an image signal from the image pickup device, comprising:

a setting step of setting electric charge accumulation periods for a plurality of first pixels and a plurality of second pixels included in the plurality of unit pixel areas as a first accumulation period and a second accumulation period, respectively;
and
a mode selection step of selecting a first mode in which an image signal for use in detecting flicker of light is obtained, or a second mode in which an image signal for use in detecting an object brightness is obtained,
wherein when the first mode is selected in the mode selection step, the first accumulation period and the second accumulation period are set in the setting step such that a first barycentric position which is a barycentric position of the first accumulation period for the plurality of first pixels included in the plurality of unit pixel areas and a second barycentric position which is a barycentric position of the second accumulation period for the plurality of second pixels included in the plurality of unit pixel areas correspond to each other,
wherein when the mode selection step selects the second mode after the flicker of light is detected in the first mode, the setting step sets the first accumulation period and the second accumulation period based on light amount changing characteristics of the flicker of light detected in the first mode,
wherein when the mode selection step selects the second mode without the flicker of light being detected in the first mode, the setting step sets the first accumulation period and the second accumulation period independently of light amount changing characteristics of the flicker of light,
wherein the first accumulation period and the second accumulation period at least partially overlap each other, and
wherein in the second mode, the first accumulation period is different in length of time from the second accumulation period.

5 more elements

A non-transitory computer-readable storage medium storing a program for causing a computer to execute a control method for an image pickup apparatus which has an image pickup device having a plurality of unit pixel areas arranged in a two-dimensional matrix and obtains an image signal from the image pickup device, the control method comprising:

a setting step of setting electric charge accumulation periods for a plurality of first pixels and a plurality of second pixels included in the plurality of unit pixel areas as a first accumulation period and a second accumulation period, respectively;
and
a mode selection step of selecting a first mode in which an image signal for use in detecting flicker of light is obtained, or a second mode in which an image signal for use in detecting an object brightness is obtained,
wherein when the first mode is selected in the mode selection step, the first accumulation period and the second accumulation period are set in the setting step such that a first barycentric position which is a barycentric position of the first accumulation period for the plurality of first pixels included in the plurality of unit pixel areas and a second barycentric position which is a barycentric position of the second accumulation period for the plurality of second pixels included in the plurality of unit pixel areas correspond to each other,
wherein when the mode selection step selects the second mode after the flicker of light is detected in the first mode, the setting step sets the first accumulation period and the second accumulation period based on light amount changing characteristics of the flicker of light detected in the first mode,
wherein when the mode selection step selects the second mode without the flicker of light being detected in the first mode, the setting step sets the first accumulation period and the second accumulation period independently of light amount changing characteristics of the flicker of light,
wherein the first accumulation period and the second accumulation period at least partially overlap each other, and
wherein in the second mode, the first accumulation period is different in length of time from the second accumulation period.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/723,806Filed 28 May 2015
Priority: JP 2014-1157494 Jun 2014
Published: US 2015/0358570 A110 Dec 2015
Granted: 26 Dec 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04N 23/745
Circuitry for compensating brightness variation in the scene: detection of flicker frequency or suppression of flicker wherein the flicker is…
H04N 23/73
Circuitry for compensating brightness variation in the scene: by influencing the exposure time
H04N 25/533
Control of the integration time: by using differing integration times for different sensor regions
H04N 25/585
Acquired simultaneously: with pixels having different sensitivities within the sensor, e.g. fast or slow pixels or pixels having different sizes