JPH07118786B2 - Imaging device - Google Patents
Imaging deviceInfo
- Publication number
- JPH07118786B2 JPH07118786B2 JP60251401A JP25140185A JPH07118786B2 JP H07118786 B2 JPH07118786 B2 JP H07118786B2 JP 60251401 A JP60251401 A JP 60251401A JP 25140185 A JP25140185 A JP 25140185A JP H07118786 B2 JPH07118786 B2 JP H07118786B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- gain
- image pickup
- level
- screen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000003384 imaging method Methods 0.000 title claims description 11
- 238000001514 detection method Methods 0.000 claims description 27
- 230000002093 peripheral effect Effects 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 8
- 230000003321 amplification Effects 0.000 description 7
- 238000003199 nucleic acid amplification method Methods 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000012935 Averaging Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
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- Exposure Control For Cameras (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明はビデオカメラ等の撮像装置に関するもので、特
に、画面の状態に応じて適正な利得制御を行う撮像装置
に関するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device such as a video camera, and more particularly to an image pickup device that performs appropriate gain control according to the state of a screen.
従来の技術 ビデオカメラにおいては、人物等の主要被写体と背景に
平均的に光が当っている順光の場合を撮像したときは良
好な画像が得られるが、空を背景にして人物等の主要被
写体が画面の中央に位置する逆光の場合を撮像したとき
は被写体が暗くなる欠点があった。これは、従来の絞り
制御機構が撮像信号の平均レベル、あるいはピークレベ
ルを一定にするように制御されているためである。2. Description of the Related Art With a video camera, a good image can be obtained when a normal subject, such as a person, and the background are normally illuminated, but a good image can be obtained. There is a defect that the subject becomes dark when the subject is backlit in the center of the screen. This is because the conventional aperture control mechanism is controlled so as to keep the average level or peak level of the image pickup signal constant.
第２図は、１フレームの撮像信号から画像を細かく小領
域に分割し、画面上での明るさとその明るさを有する小
領域の度数の関係を示したものであり横軸には画面上で
の明るさに対応した撮像信号のレベルを目盛ってある。
第２図（ａ）は、順光撮像の場合であり撮像信号の平均
レベルAVを中心とした分布をしている。この時、一般的
に画面中央に位置する主要被写体の平均レベルと撮像信
号全体の平均レベルAVとは等しくなるため、平均レベル
で絞りを制御すれば主要被写体は適正なレベルを得られ
る。FIG. 2 shows the relationship between the brightness on the screen and the frequency of the small area having the brightness, in which the image is finely divided into small areas from the image pickup signal of one frame. The level of the image pickup signal corresponding to the brightness of is graduated.
FIG. 2A shows the case of forward light imaging, and the distribution is centered on the average level AV of the imaging signal. At this time, generally, the average level of the main subject located at the center of the screen is equal to the average level AV of the entire image pickup signal, so that the proper level of the main subject can be obtained by controlling the aperture at the average level.
第２図（ｂ）は逆光撮像の場合であり背景の非常に明る
い領域が振幅の大きい部分に第１の山を形成し、さらに
人物等の主要被写体が振幅の小さい部分に第２の山を形
成している。この時、画面中央部の主要被写体の平均レ
ベルP1と画像信号全体の平均レベルAVとは異なってお
り、平均レベルAVで絞りを制御すれば主要被写体が暗く
なってしまう。FIG. 2B shows a case of backlight imaging, in which a very bright area of the background forms a first mountain in a portion having a large amplitude, and a main subject such as a person forms a second mountain in a portion having a small amplitude. Is forming. At this time, the average level P 1 of the main subject in the center of the screen is different from the average level AV of the entire image signal, and if the aperture is controlled by the average level AV, the main subject becomes dark.
そこで、従来方式を改良した絞り制御装置が発表されて
おり、例えば特開昭55−87129号公報に示されている。Therefore, an aperture control device improved from the conventional system has been announced, for example, as disclosed in Japanese Patent Laid-Open No. 55-87129.
第７図はこの従来の絞り制御装置のブロック構成図を示
すものであり、１はレンズ、２は絞り、３は撮像デバイ
ス、４は撮像デバイス３の出力信号を増幅して所定レベ
ルの撮像信号を得るための増幅回路、５はガンマ補正等
の信号波形処理を行う信号処理回路、６は撮像信号が増
加すると増幅度の絶対値を減少させる特性を有する非直
線増幅回路、７は非直線増幅回路６の出力信号の平均レ
ベルを検出する平均レベル検出回路、８は前記平均レベ
ルと基準レベルVLとを比較して絞り制御信号を出力する
比較回路、９は絞りを駆動する駆動回路である。FIG. 7 shows a block diagram of the conventional aperture control device, in which 1 is a lens, 2 is an aperture, 3 is an image pickup device, and 4 is an image pickup signal having a predetermined level by amplifying an output signal of the image pickup device 3. To obtain the signal waveform, 5 is a signal processing circuit that performs signal waveform processing such as gamma correction, 6 is a non-linear amplification circuit having the characteristic of decreasing the absolute value of the amplification degree when the image pickup signal increases, and 7 is non-linear amplification An average level detection circuit for detecting the average level of the output signal of the circuit 6, 8 is a comparison circuit for comparing the average level with the reference level V L and outputting an aperture control signal, and 9 is a drive circuit for driving the aperture. .
以上のように構成された絞り制御装置においては、非直
線増幅回路６を、第３図に示す特性にすることにより逆
光に相当する撮像信号の振幅を圧縮して、平均レベル検
出回路７の出力信号が大きくならないようにしている。
また、一般に撮像したい主要被写体は中央部にあるので
非直線増幅回路６の画面中央部の利得を周辺部の利得よ
り大きくして、周辺部の撮像信号が絞りの制御信号に大
きく影響しないようにして、逆行時や光源を含む撮像時
絞りが閉じて画面中央部が暗くなりすぎるのを防いでい
る。In the aperture control device configured as described above, the amplitude of the image pickup signal corresponding to the backlight is compressed by setting the characteristic of the non-linear amplification circuit 6 to the output of the average level detection circuit 7. I try to prevent the signal from becoming large.
Further, since the main subject to be imaged is generally located in the central portion, the gain of the central portion of the screen of the non-linear amplification circuit 6 is made larger than that of the peripheral portion so that the image signal of the peripheral portion does not significantly affect the control signal of the aperture. This prevents the central part of the screen from becoming too dark due to the closing of the diaphragm at the time of retrogression or imaging including the light source.
発明が解決しようとする問題点 しかしながら上記のような構成では、非直線増幅回路６
の特性で所定レベル以上の信号を圧縮することにより補
正を行うため不適性な補正が行われる場合がある。例え
ば画面が一様でかつ非常に明るい場合には、撮像信号が
非直線増幅回路６により圧縮されてしまい平均レベル検
出回路７の出力信号が補正しない場合に比較して絞りを
開く方向に変化することなく問題である。また、非直線
増幅回路６の画面中央部の利得を周辺部の利得より大き
くして、周辺部の撮像信号の影響を小さくしても強い光
源が画面周辺部に位置する場合には画面中央部はその影
響により若干暗くなる。一方、画面周辺部の影響を無く
すために非直線増幅回路６の周辺部の利得を零とした場
合は、強い光源が画面周辺部に入った時撮像デバイス３
の出力信号が飽和してしまい問題であった。Problems to be Solved by the Invention However, in the above configuration, the nonlinear amplifier circuit 6
Since the correction is performed by compressing a signal of a predetermined level or more with the characteristic of 1, the inappropriate correction may be performed. For example, when the screen is uniform and very bright, the image pickup signal is compressed by the non-linear amplification circuit 6 and the output signal of the average level detection circuit 7 changes to open the aperture as compared with the case where it is not corrected. Is a problem without. Further, when the gain of the central portion of the screen of the non-linear amplification circuit 6 is made larger than the gain of the peripheral portion to reduce the influence of the image signal of the peripheral portion, if the strong light source is located in the peripheral portion of the screen, the central portion of the screen is Will be a little darker due to the effect. On the other hand, when the gain of the peripheral portion of the nonlinear amplifier circuit 6 is set to zero in order to eliminate the influence of the peripheral portion of the screen, when the strong light source enters the peripheral portion of the screen, the imaging device 3
The output signal of was saturated, which was a problem.
本発明はかかる点に鑑み、逆光時や周辺部に光源等を含
む被写体を撮像した時に、画面中央部の主要被写体の信
号レベルを利得制御により適切に補正する撮像装置を提
供することを目的とする。In view of such a point, an object of the present invention is to provide an image pickup apparatus that appropriately corrects the signal level of a main subject in the center of the screen by gain control when the subject is backlit or when a subject including a light source or the like is imaged in the peripheral portion. To do.
問題点を解決するための手段 本発明は撮像画面の中央部の撮像信号のレベルを検出す
る第１レベル検出部と、前記撮像画面の中央部を除いた
周辺部の撮像信号のレベルを検出する第２レベル検出部
と、前記第１レベル検出部と前記第２レベル検出部の出
力信号の比、あるいは差に応じた値を出力する演算部
と、前記演算部の出力信号により撮像信号の振幅を変え
るゲインコントロール部とを備えた撮像装置である。Means for Solving the Problems The present invention detects a level of an image pickup signal in a central portion of an image pickup screen and a level of an image pickup signal in a peripheral portion of the image pickup screen excluding the central portion. A second level detection unit, a calculation unit that outputs a value according to the ratio or difference between the output signals of the first level detection unit and the second level detection unit, and the amplitude of the imaging signal based on the output signal of the calculation unit And a gain control unit for changing the.
作用 本発明は前記した構成により、演算部が、第１レベル検
出部の出力信号P1と第２レベル検出部の出力信号P2とを
演算処理することにより画像周辺部に光源等を含んだ状
態かどうか判別し、その状態に応じてゲインコントロー
ル部の利得を連続的に制御して画像中央部が適正な信号
レベルになるように補正を行うものである。The present invention has the above-described configuration, and the arithmetic unit includes a light source and the like in the image peripheral portion by performing arithmetic processing on the output signal P 1 of the first level detecting unit and the output signal P 2 of the second level detecting unit. Whether the state is a state or not is determined, and the gain of the gain control unit is continuously controlled according to the state to perform correction so that the central portion of the image has an appropriate signal level.
実 施 例 第１図は本発明の第１の実施例における撮像装置のブロ
ック構成図である。第１図において、１はレンズ、２は
絞り、３は撮像デバイス、４は増幅回路で、以上は第７
図の構成と同様なものである。10はAD変換回路で撮像信
号をディジタル化する。11はAD変換回路10の出力信号と
演算回路18の出力信号とを乗算する機能を有するゲイン
コントロール回路でゲインコントロール部を構成してい
る。5aはガンマ補正等の信号処理を行い映像信号を出力
する信号処理回路、12はディジタル化した映像信号をア
ナログに変換するDA変換回路である。AD変換回路10の出
力信号はゲート回路14、ゲート回路16に供給される。ゲ
ート回路14は第４図に示す撮像画面において画面中央部
S1の撮像信号をレベル検出回路15に供給し、ゲート回路
16は画面周辺部S2の撮像信号をレベル検出回路17に供給
する。13はゲートパルスを発生してゲート回路を制御す
るゲートパルス発生回路である。Practical Example FIG. 1 is a block diagram of an image pickup apparatus according to a first example of the present invention. In FIG. 1, 1 is a lens, 2 is a diaphragm, 3 is an imaging device, 4 is an amplifier circuit, and the above is the seventh.
The configuration is similar to that shown in the figure. Reference numeral 10 is an AD conversion circuit that digitizes the image pickup signal. Reference numeral 11 is a gain control circuit having a function of multiplying the output signal of the AD conversion circuit 10 and the output signal of the arithmetic circuit 18, and constitutes a gain control section. Reference numeral 5a is a signal processing circuit for performing signal processing such as gamma correction and outputting a video signal, and 12 is a DA conversion circuit for converting a digitized video signal into an analog signal. The output signal of the AD conversion circuit 10 is supplied to the gate circuit 14 and the gate circuit 16. The gate circuit 14 is located at the center of the screen on the image pickup screen shown in FIG.
The image signal of S 1 is supplied to the level detection circuit 15, and the gate circuit
Reference numeral 16 supplies the image pickup signal of the screen peripheral portion S 2 to the level detection circuit 17. Reference numeral 13 is a gate pulse generation circuit for generating a gate pulse and controlling the gate circuit.
レベル検出回路15はゲート回路14の出力信号を加算平均
して画面中央部撮像信号の振幅の平均値P1を出力し、レ
ベル検出回路17はレベル検出回路15と同様な回路で画面
周辺部撮像信号の振幅の平均値P2を出力する。ゲート回
路14とレベル検出回路15は第１レベル検出部を構成し、
ゲート回路16とレベル検出回路17は第２レベル検出部を
構成している。The level detection circuit 15 averages the output signals of the gate circuit 14 and outputs the average value P 1 of the amplitude of the image pickup signal in the central portion of the screen, and the level detection circuit 17 uses the same circuit as the level detection circuit 15 to image the peripheral portion of the screen. The average value P 2 of the signal amplitude is output. The gate circuit 14 and the level detection circuit 15 constitute a first level detection unit,
The gate circuit 16 and the level detection circuit 17 form a second level detection unit.
19はレベル検出回路15の出力信号P1とレベル検出回路17
の出力信号P2を入力として画面全体の平均値P0を で求めて出力する混合回路、20は混合回路19の出力信号
と基準レベルVTとを比較して誤差信号を出力する比較回
路、９は前記誤差信号により絞り２を駆動する駆動回路
である。19 is the output signal P 1 of the level detection circuit 15 and the level detection circuit 17
The average value P 0 of the entire screen output signal P 2 as input A reference numeral 20 is a comparison circuit for comparing the output signal of the mixing circuit 19 with the reference level V T to output an error signal, and a reference numeral 9 is a drive circuit for driving the diaphragm 2 by the error signal.
一方、レベル検出回路15とレベル検出回路17の出力信号
は演算部を構成する演算回路18に供給される。演算回路
18は第５図（ａ）に示す特性を有する。第５図において
横軸は画面中央部と画面周辺部の撮像信号の平均値の比
P2/P1であり、縦軸は演算回路18の出力信号でありゲイ
ンコントロール回路11の利得を決めている。On the other hand, the output signals of the level detection circuit 15 and the level detection circuit 17 are supplied to the arithmetic circuit 18 which constitutes the arithmetic unit. Arithmetic circuit
18 has the characteristics shown in FIG. In Fig. 5, the horizontal axis is the ratio of the average value of the image pickup signals in the central part of the screen and the peripheral part of the screen.
P 2 / P 1 and the vertical axis is the output signal of the arithmetic circuit 18 and determines the gain of the gain control circuit 11.
以上のように構成された本実施例の撮像装置について以
下その動作を説明する。The operation of the image pickup apparatus of the present embodiment configured as described above will be described below.
画面周辺部に光源等を含んだ撮像の場合、画面周辺部の
撮像信号の平均レベルP2と画面中央部の平均レベルP1は
第２図（ｃ）に示すようになる。ここで絞り２は上式で
示したようにP1とP2の平均値P0で制御するために一般に
主要被写体が位置する画面中央部が暗く映ることにな
る。一方、P1とP2の比をｋとすると これを（１）式に代入すると となる。そこで、本実施例の場合に の利得をゲインコントロール回路11に与えれば画面中央
部の平均レベルは適正レベルまで補正できる。例えばｋ
＝３の時利得は２となる。第５図（ａ）では最大利得を
２に制限しているが、これはノイズとの関係によって決
められるもので２に限ることはない。なお、本実施例に
おいては利得を２倍まで可変にするため、撮像デバイス
３からの最大振幅の信号が出力された時ゲインコントロ
ール回路11で所定レベルを越えてしまう。そこで、信号
処理回路5aは第６図のａに示すガンマ補正特性を有して
いる。特性ａは一般的な特性ｂに比較して振幅の大きい
信号が入力しても出力信号はクリップされることなく圧
縮できるようになっている。なお、特性ａは１例であっ
てこれに限る必要はない。In the case of imaging in which the light source or the like is included in the peripheral portion of the screen, the average level P 2 of the image pickup signal in the peripheral portion of the screen and the average level P 1 in the central portion of the screen are as shown in FIG. 2 (c). Here, since the diaphragm 2 is controlled by the average value P 0 of P 1 and P 2 as shown in the above equation, the central portion of the screen where the main subject is generally located appears dark. On the other hand, if the ratio of P 1 and P 2 is k Substituting this into equation (1) Becomes Therefore, in the case of this embodiment, By applying the gain of 1 to the gain control circuit 11, the average level at the center of the screen can be corrected to an appropriate level. Eg k
When = 3, the gain is 2. Although the maximum gain is limited to 2 in FIG. 5 (a), this is determined by the relationship with noise and is not limited to 2. In this embodiment, since the gain is variable up to 2 times, the gain control circuit 11 exceeds a predetermined level when the maximum amplitude signal is output from the image pickup device 3. Therefore, the signal processing circuit 5a has the gamma correction characteristic shown in a of FIG. The characteristic a is designed so that the output signal can be compressed without being clipped even when a signal having a larger amplitude than the general characteristic b is input. It should be noted that the characteristic a is an example and is not limited to this.
以上のように本実施例によれば、自動絞り制御装置を有
する撮像装置において、画面周辺部に螢光灯等の光源が
入った時に、その影響を受けて画面中央部が暗く映って
いたのを、ゲインコントロール回路の利得を制御して適
正な明るさに自動的に補正することができる。したがっ
て空を背景に人物等を映す逆光時や画面周辺部に光源等
を含む被写体の撮像時でも画面中央部の主要被写体は特
別の操作を行わないでも常に一定の明るさを維持するこ
とができる。As described above, according to the present embodiment, in the image pickup apparatus having the automatic aperture control device, when a light source such as a fluorescent lamp enters the peripheral portion of the screen, the central portion of the screen appears dark due to the influence of the light source. Can be automatically corrected to an appropriate brightness by controlling the gain of the gain control circuit. Therefore, even when the subject is backlit against the sky or when the subject including the light source is captured in the periphery of the screen, the main subject in the center of the screen can always maintain a constant brightness without any special operation. .
次に、第１実施例の演算回路18、混合回路19の特性を変
えた他の実施例を以下に説明する。Next, another embodiment in which the characteristics of the arithmetic circuit 18 and the mixing circuit 19 of the first embodiment are changed will be described below.
前記実施例において混合回路19は画面周辺部と画面中央
部の振幅の平均値を単純平均して画面全体の振幅の平均
値を求め絞りを制御していたが、周辺部の撮像信号が絞
りの制御に大きく影響しないように画面中央部に重み付
けをした絞りの制御も可能である。混合回路19の出力信
号PWが PW＝m1P1＋m2P2 …（３）（m1＞m2,m1＋m2＝１） で示されるとき画面の中央部に重み付けられた絞りの制
御が行える。このとき、P2＝kP1を（３）式に代入して PW＝m1P1＋m2・kP1 ＝（m1＋m2k）P1 ……（４） となる。よってP1とP2の比ｋに応じてm1＋m2k倍の利得
をゲインコントロール11に与えることによって画面中央
部の振幅レベルは補正レベルまで補正できる。第２の実
施例として、 とした時の演算回路18の特性を第５図（ｂ）に示す。In the embodiment, the mixing circuit 19 controls the diaphragm by obtaining the average value of the amplitude of the entire screen by simply averaging the average values of the amplitudes of the peripheral portion of the screen and the central portion of the screen. It is also possible to control the aperture by weighting the central portion of the screen so that the control is not greatly affected. When the output signal P W of the mixing circuit 19 is represented by P W = m 1 P 1 + m 2 P 2 (3) (m 1 > m 2 , m 1 + m 2 = 1), the weighting is applied to the center of the screen. The diaphragm can be controlled. At this time, P 2 = kP 1 is substituted into the equation (3), and P W = m 1 P 1 + m 2 · kP 1 = (m 1 + m 2 k) P 1 (4) Therefore, the amplitude level at the center of the screen can be corrected to the correction level by giving the gain control 11 a gain of m 1 + m 2 k times according to the ratio k of P 1 and P 2 . As a second embodiment, The characteristic of the arithmetic circuit 18 in such a case is shown in FIG.
この第２の実施例においては、画面中央部に重み付けし
た絞りの制御を行うことによって演算回路18の特性曲線
がなだらかになり、第１の実施例と比較してゲインコン
トロール回路11の最大利得は同じでも画面中央部を一定
レベルに補正できる画像の範囲は の値で4/3倍に拡大しており、第１の実施例と比較して
より多くの場面で光源等により影響のない撮像が可能で
ある。In the second embodiment, the characteristic curve of the arithmetic circuit 18 becomes smooth by controlling the aperture weighted in the center of the screen, and the maximum gain of the gain control circuit 11 is larger than that of the first embodiment. Even if the same, the range of the image that can correct the central part of the screen to a certain level is The value is 4/3 times larger than that of the first embodiment, and it is possible to perform imaging without being affected by the light source or the like in more scenes than in the first embodiment.
なお、第１および第２の実施例における演算回路18の特
性は任意に決めることができる。例えば、第２の実施例
における別の例として第５図（ｃ）に示す。これは、 の範囲はゲインコントロール回路11の補正量が少ないた
めに利得１で近似し、 の範囲は第５図（ｂ）の特性曲線と同じ傾きで利得を上
げている。この方法によれば、画面中央部のレベルは若
干小さめになるが の範囲ではゲインコントロール回路11の制御が簡単で、
さらに利得補正のできる範囲が第２の実施例に比較して
拡大している。The characteristics of the arithmetic circuit 18 in the first and second embodiments can be arbitrarily determined. For example, another example of the second embodiment is shown in FIG. 5 (c). this is, The range of is approximated by gain 1 because the correction amount of gain control circuit 11 is small, In the range of, the gain is increased with the same slope as the characteristic curve of FIG. According to this method, the level at the center of the screen becomes slightly smaller, In the range of, the control of the gain control circuit 11 is easy,
Further, the range in which the gain can be corrected is expanded as compared with the second embodiment.
なお、上記実施例においては、演算回路18はP1とP2の比
に応じてゲインコントロール回路11を制御したが、P1と
P2の比の大小は、P1とP2の差の大小と対応するので、P1
とP2の差に応じてゲインコントロール回路11を制御する
構成としても、本実施例と同様の効果が得られるのは明
かである。In the above embodiment, the arithmetic circuit 18 controls the gain control circuit 11 according to the ratio of P1 and P2.
The magnitude of the P2 ratio corresponds to the magnitude of the difference between P1 and P2.
Even if the gain control circuit 11 is controlled in accordance with the difference between P2 and P2, it is obvious that the same effect as this embodiment can be obtained.
発明の効果 以上説明したように、本発明によれば、逆光や光源等を
画面の周辺部に含んだ被写体を撮像した場合に、従来画
面中央部が暗く映っていたのを適正な明るさになるよう
に自動的に補正することができる。したがって、画面中
央部の主要被写体は画面周辺部の光源あるいは空などの
影響を受けないで一定の明るさを維持することができ
る。EFFECTS OF THE INVENTION As described above, according to the present invention, when a subject including a backlight, a light source, or the like in the peripheral portion of the screen is imaged, the central portion of the screen that is dark in the past is displayed with proper brightness. Can be automatically corrected so that Therefore, the main subject in the central part of the screen can maintain a constant brightness without being affected by the light source in the peripheral part of the screen or the sky.
第１図は本発明における一実施例の撮像装置のブロック
図、第２図は撮像画面の明るさと度数の関係を示す図、
第３図は従来の撮像装置の非直線増幅回路の特性図、第
４図は撮像画面の分割図、第５図は本発明の各実施例の
演算回路の特性図、第６図は本発明の実施例のガンマ特
性図、第７図は従来の撮像装置のブロック図である。 ２……絞り、5a……信号処理回路、11……ゲインコント
ロール回路、13……ゲートパルス発生回路、14,16……
ゲート回路、15,17……レベル検出回路、18……演算回
路、19……混合回路。FIG. 1 is a block diagram of an image pickup apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing a relationship between the brightness of an image pickup screen and frequency.
FIG. 3 is a characteristic diagram of a non-linear amplifier circuit of a conventional image pickup device, FIG. 4 is a divided diagram of an image pickup screen, FIG. 5 is a characteristic diagram of an arithmetic circuit of each embodiment of the present invention, and FIG. 6 is the present invention. 7 is a block diagram of a conventional image pickup device. 2 ... Aperture, 5a ... Signal processing circuit, 11 ... Gain control circuit, 13 ... Gate pulse generation circuit, 14, 16 ...
Gate circuit, 15, 17 ... Level detection circuit, 18 ... Arithmetic circuit, 19 ... Mixed circuit.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 松岡 宏樹 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (56)参考文献 特開 昭60−214168（ＪＰ，Ａ) 特開 昭60−16072（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroki Matsuoka Inventor Hiroki Matsuoka 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-60-214168 (JP, A) JP-A-60-16072 (JP, A)
Claims (2)
出する第１レベル検出部と、 前記撮像画面の中央部を除いた周辺部の撮像信号のレベ
ルを検出する第２レベル検出回路と、 前記第１レベル検出部と前記第２レベル検出部の出力信
号を入力として演算処理を行う演算部と、 前記演算部の出力信号に応じて撮像信号の利得を制御す
るゲインコントロール部とを備え、 前記演算部が、第１レベル検出部と第２レベル検出部の
出力信号を比較して、第２レベル検出部の出力が相対的
に大きくなるにしたがって、連続的に利得を上げるか、
もしくは利得を一定にする制御信号を出力することを特
徴とする撮像装置。1. A first level detection unit for detecting a level of an image pickup signal in a central portion of an image pickup screen, and a second level detection circuit for detecting a level of an image pickup signal in a peripheral portion excluding the central portion of the image pickup screen. A calculation unit that performs a calculation process using the output signals of the first level detection unit and the second level detection unit as an input; and a gain control unit that controls the gain of the imaging signal according to the output signal of the calculation unit. The calculation unit compares the output signals of the first level detection unit and the second level detection unit and continuously increases the gain as the output of the second level detection unit becomes relatively large,
Alternatively, an image pickup device which outputs a control signal for making a gain constant.
と第２レベル検出部の出力信号P2との比の値P2/P1が、
予め定めた値より大きい時のゲインコントロール部の利
得Ｇが基準となる利得G0に対してＧ≧G0を満たし、 前期比の値が前記予め定めた値より小さいときのゲイン
コントロール部の利得ＧがＧ≦G0を満たすような信号を
出力することを特徴とする特許請求の範囲第１項記載の
撮像装置。2. The arithmetic unit outputs the output signal P1 of the first level detector.
And the value P2 / P1 of the ratio between the output signal P2 of the second level detector and
The gain G of the gain control section when the value is larger than a predetermined value satisfies G ≧ G0 with respect to the reference gain G0, and the gain G of the gain control section when the value of the previous period is smaller than the predetermined value is The image pickup apparatus according to claim 1, which outputs a signal satisfying G ≦ G0.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60251401A JPH07118786B2 (en) | 1985-11-08 | 1985-11-08 | Imaging device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60251401A JPH07118786B2 (en) | 1985-11-08 | 1985-11-08 | Imaging device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62110369A JPS62110369A (en) | 1987-05-21 |
| JPH07118786B2 true JPH07118786B2 (en) | 1995-12-18 |
Family
ID=17222293
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60251401A Expired - Lifetime JPH07118786B2 (en) | 1985-11-08 | 1985-11-08 | Imaging device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07118786B2 (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2508486B2 (en) * | 1987-06-08 | 1996-06-19 | ソニー株式会社 | Backlight compensation circuit for video camera |
| JP2527592B2 (en) * | 1988-02-25 | 1996-08-28 | 三洋電機株式会社 | Imaging device |
| AU607033B2 (en) * | 1988-01-12 | 1991-02-21 | Sanyo Electric Co., Ltd. | Auto iris/gamma correction apparatus for making automatic exposure adjustment and/or automatic gamma correction in response to video signal and image sensing apparatus comprising such auto iris/gamma correction apparatus |
| JP2898987B2 (en) * | 1988-03-18 | 1999-06-02 | キヤノン株式会社 | Exposure control device |
| EP0341692B1 (en) * | 1988-05-11 | 1994-04-20 | Sanyo Electric Co., Ltd. | Image sensing apparatus having automatic focusing function for automatically matching focus in response to video signal |
| US4969045A (en) * | 1988-05-20 | 1990-11-06 | Sanyo Electric Co., Ltd. | Image sensing apparatus having automatic iris function of automatically adjusting exposure in response to video signal |
| JP2547619B2 (en) * | 1988-05-20 | 1996-10-23 | 三洋電機株式会社 | Imaging device |
| JP2797341B2 (en) * | 1988-10-18 | 1998-09-17 | ソニー株式会社 | Camera backlight compensation circuit |
| JPH02166885A (en) * | 1988-12-20 | 1990-06-27 | Matsushita Electric Ind Co Ltd | Image pickup device |
| JPH02288561A (en) * | 1989-04-28 | 1990-11-28 | Matsushita Electric Ind Co Ltd | Video camera device |
| US5068719A (en) * | 1989-06-07 | 1991-11-26 | Olympus Optical Co., Ltd. | Endoscope photometric apparatus |
| US5111301A (en) * | 1989-06-28 | 1992-05-05 | Sanyo Electric Co., Ltd. | Automatic exposure adjusting apparatus for automatically adjusting exposure by fuzzy inference |
| KR920007905Y1 (en) * | 1989-09-12 | 1992-10-22 | 삼성전자 주식회사 | Auto-white balance enabling circuit |
| JP2899031B2 (en) * | 1989-12-28 | 1999-06-02 | キヤノン株式会社 | Automatic exposure control device |
| US5049989A (en) * | 1990-01-04 | 1991-09-17 | Olympus Optical Co., Ltd. | Method and circuit for reducing the influence of a bright image area in an endoscope image signal |
| US5221963A (en) * | 1990-03-31 | 1993-06-22 | Minolta Camera Kabushiki Kaisha | Video camera having a video signal processing apparatus |
| JP3548465B2 (en) | 1999-09-08 | 2004-07-28 | キヤノン株式会社 | Imaging device and imaging method |
| JP4576658B2 (en) | 2000-02-29 | 2010-11-10 | ソニー株式会社 | Imaging apparatus, imaging method, and imaging program |
| DE112015006032B4 (en) * | 2015-01-22 | 2021-04-01 | Mitsubishi Electric Corporation | Apparatus and method for image acquisition of an object located in an imaging field angular range, program and recording medium |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6016072A (en) * | 1983-07-07 | 1985-01-26 | Canon Inc | Image pickup device |
| JPS60214168A (en) * | 1984-04-10 | 1985-10-26 | Fuji Photo Film Co Ltd | Back light correction circuit in video camera |
-
1985
- 1985-11-08 JP JP60251401A patent/JPH07118786B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62110369A (en) | 1987-05-21 |
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| EXPY | Cancellation because of completion of term |