JP2015056758A5

JP2015056758A5 -

Info

Publication number: JP2015056758A5
Application number: JP2013188718A
Authority: JP
Filing date: 2013-09-11
Publication date: 2016-10-20
Anticipated expiration: 2033-09-11

Description

本発明は、撮像装置、その制御方法、及び制御プログラムに関し、更に詳しくは、高ダイナミックレンジ動画を取得するための合成用の画像を取得する撮像装置、その制御方法、及び制御プログラムに関する。 The present invention relates to an imaging apparatus, a control method thereof, and a control program. More specifically, the present invention relates to an imaging apparatus that acquires an image for synthesis for acquiring a high dynamic range moving image, a control method thereof, and a control program.

本発明は上記問題点を鑑みてなされたものであり、フリッカ検出結果に応じて最適な露出制御を行い、フリッカによる画質劣化の無い高ダイナミックレンジ動画を取得することを目的とする。 The present invention has been made in view of the above problems, and an object of the present invention is to perform optimal exposure control in accordance with the flicker detection result and obtain a high dynamic range moving image free from image quality deterioration due to flicker.

上記目的を達成するために、本発明の撮像装置は、電荷蓄積時間を制御することができ、光電変換して得られた画像信号を出力する撮像素子と、前記撮像素子から出力された画像信号に基づいて、光源のフリッカの有無及びフリッカが発生している場合にはフリッカの周波数を検出する検出手段と、少なくとも１つの発生し得るフリッカの周波数に対応したプログラム線図を含む、複数のプログラム線図を記憶した記憶手段と、前記記憶手段に記憶された複数のプログラム線図のうち、前記検出手段の検出結果に対応するプログラム線図を選択する選択手段と、前記選択手段により選択されたプログラム線図に基づく複数の異なる露出値で被写体を撮影するように制御する制御手段と、前記複数の異なる露出値で被写体を撮影することで得られた複数の画像を合成して、ダイナミックレンジが拡大された１枚の画像を得る合成手段とを有し、前記フリッカの周波数に対応したプログラム線図は、前記フリッカの周波数をｆとした場合に、１／（ｆ×２）（秒）と、１／ｆ（秒）と、１／（ｆ÷２）（秒）とに電荷蓄積時間を変更することで複数の異なる露出値を設定可能であることを特徴とする。 In order to achieve the above object, an image pickup apparatus of the present invention can control a charge accumulation time and outputs an image signal obtained by photoelectric conversion, and an image signal output from the image pickup element. A plurality of programs including detection means for detecting the presence or absence of flicker of a light source and a flicker frequency when flicker occurs, and a program diagram corresponding to at least one flicker frequency that can be generated A storage unit that stores a diagram, a selection unit that selects a program diagram corresponding to a detection result of the detection unit among a plurality of program diagrams stored in the storage unit, and a selection unit selected by the selection unit and control means for photographing an object at a plurality of different exposure values based on the program diagram, obtained al by photographing an object at the plurality of different exposure values And a combining unit that combines a plurality of images to obtain a single image with an expanded dynamic range, and the program diagram corresponding to the flicker frequency is when the flicker frequency is f. , and 1 / (f × 2) (sec), 1 / f and (s), 1 / (f ÷ 2) (seconds) and the settable multiple different exposure values by changing the charge accumulation time It is characterized by being .

以上説明したように、フリッカ検出結果に応じて最適な露出制御を行い、フリッカによる画質劣化の生じない画質の高ダイナミックレンジ動画を取得することができる。 As described above, optimal exposure control is performed according to the flicker detection result, and a high dynamic range moving image with image quality that does not cause image quality degradation due to flicker can be acquired .

システム制御部１１１は、検出されたフリッカ周波数ｆ（Ｈｚ）から、フリッカを抑制するシャッタースピードを決定する。動画撮影を行うためには、通常フレームレートより高い（高速な）シャッタースピード（電荷蓄積時間）で撮影する。例えば６０Ｈｚのフリッカ光源であると判別した場合は、シャッタースピードは１／３０（秒）、１／６０（秒）、１／１２０（秒）となる。つまり、通常のフリッカの発生する蛍光灯光源下で動画撮影を行う場合に、フリッカを抑制することのできるシャッタースピード（電荷蓄積時間）は、フリッカ周波数ｆとすると、１／（ｆ×２）（秒）、１／ｆ（秒）、１／（ｆ÷２）（秒）である。 The system control unit 111 determines a shutter speed for suppressing flicker from the detected flicker frequency f (Hz). In order to perform moving image shooting, shooting is performed at a shutter speed (charge accumulation time) higher (faster) than the normal frame rate. For example, when it is determined that the flicker light source is 60 Hz, the shutter speed is 1/30 (second), 1/60 (second), and 1/120 (second). In other words, when shooting moving images under a fluorescent light source that generates normal flicker, the shutter speed (charge accumulation time) that can suppress flicker is 1 / ( f × 2 ) ( Second), 1 / f (second), 1 / ( f / 2 ) (second).

フリッカ検出部１０４でフリッカ検出した場合、システム制御部１１１は、フリッカを抑制可能なシャッタースピード（フリッカ周波数ｆとすると、１／（ｆ×２）（秒）、１／ｆ（秒）、１／（ｆ÷２）（秒））で同一の露光条件で連続撮影を行う。さらに、システム制御部１１１は、画像信号の輝度階調処理、色階調処理を行い、画像データのダイナミックレンジを調整する。ダイナミックレンジ調整は、図４に示すガンマカーブを切り替える事により行う。図４は、ダイナミックレンジ調整に用いるガンマカーブを示した図であって、４０１に示す通常処理用のガンマは、通常露出で撮影を行うことにより出力信号値も通常の露出値となる。４０２、４０３は、ダイナミックレンジ拡大時のガンマカーブである。４０２は、＋１段のダイナミックレンジ拡大用のガンマカーブであり、４０３は、＋２段のダイナミックレンジ拡大用のガンマカーブである。同様に４０５、４０６は、ダイナミックレンジ縮小時に使用する時のガンマカーブである。図４に示した複数のガンマカーブは、システム制御部１１１内のメモリに記憶されている。 When the flicker detection unit 104 detects flicker, the system control unit 111 can reduce the flicker by a shutter speed (if the flicker frequency is f, 1 / ( f × 2 ) (seconds), 1 / f (seconds), 1 / ( F ÷ 2 ) (seconds)), continuous shooting is performed under the same exposure conditions. Further, the system control unit 111 performs luminance gradation processing and color gradation processing of the image signal, and adjusts the dynamic range of the image data. The dynamic range adjustment is performed by switching the gamma curve shown in FIG. FIG. 4 is a diagram showing a gamma curve used for dynamic range adjustment. In the normal processing gamma 401 shown in FIG. 4, the output signal value becomes a normal exposure value when photographing is performed with the normal exposure. Reference numerals 402 and 403 denote gamma curves when the dynamic range is expanded. Reference numeral 402 denotes a gamma curve for expanding the dynamic range of +1 stage, and reference numeral 403 denotes a gamma curve for expanding the dynamic range of +2. Similarly, reference numerals 405 and 406 denote gamma curves used when the dynamic range is reduced. A plurality of gamma curves shown in FIG. 4 are stored in a memory in the system control unit 111.

Claims

An image sensor that can control the charge accumulation time and outputs an image signal obtained by photoelectric conversion;
Detecting means for detecting the presence or absence of flicker of the light source and the flicker frequency when flicker occurs based on the image signal output from the image sensor;
Storage means for storing a plurality of program diagrams including a program diagram corresponding to at least one possible flicker frequency;
A selection unit that selects a program diagram corresponding to a detection result of the detection unit among a plurality of program diagrams stored in the storage unit;
Control means for controlling the subject to be photographed at a plurality of different exposure values based on the program diagram selected by the selection means;
Combining a plurality of images obtained by photographing the subject with the plurality of different exposure values to obtain one image with an expanded dynamic range,
Program diagram corresponding to the frequency of the flicker frequency of the flicker when the f, 1 / (f × 2 ) and (s), and 1 / f (sec), 1 / (f ÷ 2) (s) and the imaging device, characterized in that it is possible to set a plurality of different exposure values by changing the charge accumulation time.

A diaphragm,
The imaging apparatus according to claim 1, wherein the program diagram corresponding to the flicker frequency can set a plurality of different exposure values without changing an aperture.

Gain means for applying a gain to the image signal;
3. The program diagram corresponding to the flicker frequency can set a plurality of different exposure values by changing at least one of the charge accumulation time and the gain. The imaging device described in 1.

An image sensor that can control the charge accumulation time and outputs an image signal obtained by photoelectric conversion;
Detecting means for detecting the presence or absence of flicker of the light source and the flicker frequency when flicker occurs based on the image signal output from the image sensor;
By the detecting means, when the flicker is detected, the frequency of the flicker when the f, 1 / (f × 2 ) and (s), and 1 / f (sec), 1 / (f ÷ 2) (by either of the charge accumulation time of the second), and control means for controlling to perform photographing to acquire images of multiple,
Storage means for storing a plurality of gamma curves;
A selection unit that selects a gamma curve corresponding to a detection result of the detection unit among a plurality of gamma curves stored in the storage unit;
Dynamic range adjustment means for performing dynamic range adjustment using the gamma curve selected by the selection means;
An image pickup apparatus comprising: a combining unit that combines a plurality of images adjusted by the adjusting unit to obtain a single image with an expanded dynamic range.

A method for controlling an image pickup apparatus having an image pickup element capable of controlling a charge accumulation time and outputting an image signal obtained by photoelectric conversion,
A detecting step for detecting presence / absence of flicker of a light source and a flicker frequency when flicker is generated based on an image signal output from the image sensor;
Selection means, a selection step of selecting includes a program diagram corresponding to the frequency of the at least one may occur flicker, a plurality of program diagrams or al, a program diagram corresponding to the detection result of the detecting step,
The control means shoots the subject with a plurality of different exposure values in order to obtain a single image with an expanded dynamic range by combining a plurality of images using the program diagram selected in the selection step. and a control step of controlling to acquire the plurality of images by,
Program diagram corresponding to the frequency of the flicker frequency of the flicker when the f, 1 / (f × 2 ) and (s), and 1 / f (sec), 1 / (f ÷ 2) control method for an imaging apparatus, characterized in that a plurality of different exposure values by changing the charge accumulation time in the (second) can be set.

A method for controlling an image pickup apparatus having an image pickup element capable of controlling a charge accumulation time and outputting an image signal obtained by photoelectric conversion,
A detecting step for detecting presence / absence of flicker of a light source and a flicker frequency when flicker is generated based on an image signal output from the image sensor;
Control means, in the detection step, when the flicker is detected, the frequency of the flicker when the f, 1 / (f × 2 ) and (s), and 1 / f (sec), the 1 / (f ÷ 2) (s) and any of the charge accumulation time, in order to obtain one image whose dynamic range is expanded by combining a plurality of images to acquire the image of the multiple and a control step of controlling to perform imaging for,
Selection means, a selection step of selecting a gamma curve corresponding to the detection results of the plurality of gamma curve or, et al., The detection step,
A dynamic range adjustment step in which the dynamic range adjustment means adjusts the dynamic range using the gamma curve selected in the selection step ;
A method for controlling an imaging apparatus, comprising:

A control program that can be used for an imaging apparatus having an imaging element that can control the charge accumulation time and that outputs an image signal obtained through photoelectric conversion.
A detecting step for detecting presence / absence of flicker of a light source and a flicker frequency when flicker is generated based on an image signal output from the image sensor;
Selection means, a selection step of selecting includes a program diagram corresponding to the frequency of the at least one may occur flicker, a plurality of program diagrams or al, a program diagram corresponding to the detection result of the detecting step,
The control means shoots the subject with a plurality of different exposure values in order to obtain a single image with an expanded dynamic range by combining a plurality of images using the program diagram selected in the selection step. and a control step of controlling to acquire the plurality of images by,
Program diagram corresponding to the frequency of the flicker frequency of the flicker when the f, 1 / (f × 2 ) and (s), and 1 / f (sec), 1 / (f ÷ 2) (s) and a control program, characterized in that to execute a control method multiple can be set different exposure values by changing the charge accumulation time.

A control program that can be used for an imaging apparatus having an imaging element that can control the charge accumulation time and that outputs an image signal obtained through photoelectric conversion.
A detecting step for detecting presence / absence of flicker of a light source and a flicker frequency when flicker is generated based on an image signal output from the image sensor;
Control means, in the detection step, when the flicker is detected, the frequency of the flicker when the f, 1 / (f × 2 ) and (s), and 1 / f (sec), the 1 / (f ÷ 2) (s) and any of the charge accumulation time, in order to obtain one image whose dynamic range is expanded by combining a plurality of images to acquire the image of the multiple and a control step of controlling to perform imaging for,
Selection means, a selection step of selecting a gamma curve corresponding to the detection results of the plurality of gamma curve or, et al., The detection step,
A dynamic range adjustment step in which the dynamic range adjustment means adjusts the dynamic range using the gamma curve selected in the selection step ;
A control program for causing to execute a control method having.