JPH01114188A - Image pickup device - Google Patents

Abstract

PURPOSE:To always obtain optimum exposure with respect to an object having a skin color mainly by extracting plural color difference signals from an image pickup element, comparing them with a reference value so as to apply prescribed discrimination and controlling the exposure depending on the result. CONSTITUTION:An electric signal proportional to the incident luminous quantity of an object image is extracted from each picture element of an image pickup element 103. The signal is fed to a process circuit 105 and the internal matrix circuit generates a luminance signal Y and color difference signals R-Y and B-Y. The signals are compared with each reference value at comparators 121, 122. The comparator 121 outputs H when the signal is positive and outputs 1 when negative and the comparator 122 outputs H when negative and outputs 1 when positive. When outputs of both the comparators are both H, an output of the AND circuit 141 goes to H, a switch 151 is closed, a luminance signal 190 before process is fed to an integration device 163 to open the switch 152 at the same time. When the outputs are not H at the same time, the output of the circuit 141 is L and the signal 190 is fed to the integration device 162. Thus, the weight of the output of the comparator 163 is increased, both the outputs are mixed and given to the comparator 181 to control iris.

Description

【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、撮像装置、特に人物が被写体の場合に、人物
に対して常に最適な露光量を得ることを目的とするテレ
ビ用の撮像装置に関するものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an imaging device, particularly an imaging device for a television, which aims to always obtain an optimal exposure amount for a person when the subject is a person. It is related to.

［従来の技術］ 露光量を自動的に最適になるように制御するテレビカメ
ラ等の撮像装置は、既に存在しており。[Prior Art] Imaging devices such as television cameras that automatically control the exposure amount to optimize it already exist.

次の２方式に分類できる。即ち、そのひとつは前面平均
測光方式であり、他のひとつは中央重点測光（またはス
ポット測光）方式である。It can be classified into the following two methods. That is, one of them is a front average photometry method, and the other is a center-weighted photometry (or spot photometry) method.

第３図は従来の撮像装置の主要部の概略を示した図であ
る。第３図を用いて、その動作を簡単に説明する。FIG. 3 is a diagram schematically showing the main parts of a conventional imaging device. The operation will be briefly explained using FIG.

第３図において、１０１はレンズ、１０２は光量を制御
する絞り（アイリス）、１０３は撮像素子、１０４は増
幅器、３４０はゲート、３３０は積分器、１８１は比較
器、１１２はアイリス駆動回路、モして３５０はゲート
信号発生器を表わしている。In FIG. 3, 101 is a lens, 102 is an aperture (iris) that controls the amount of light, 103 is an image sensor, 104 is an amplifier, 340 is a gate, 330 is an integrator, 181 is a comparator, 112 is an iris drive circuit, and 112 is an iris drive circuit. 350 represents a gate signal generator.

いま、被写体から入射した光はレンズ１０１を通してア
イリス１０２で光量を適正に制限され、撮像素子１０３
に到達する。そして、被写体の光に応じて、撮像素子１
０３から信号電圧（電流）が得られ、これを線形増幅器
１０４で増幅して、後段のプロセス回路に導く。増幅器
１０４の出力信号は、ゲート信号発生器３５０で制御さ
れるゲート回路３４０て画面内の測光枠を決定し、この
測光枠内の信号のみ積分器３３０に導き、積分する。積
分された信号は、比較５１８１で基準レベル１Ｂ２と比
較し、その出力でアイリス駆動回路１１２を介してアイ
リス１０２を制御する。そのとき、比較器の利得が充分
大きければ、この制御ループにより、測光枠内の映像信
号の積分値３３１が基準値１８２と等しくなるようにア
イリス１０２は制御される。そして、ゲート３４０で決
定される測光枠が画面全体のとき、前面平均測光方式と
なり、測光枠が中心部の小さい面積であるとき、中央重
点測光あるいはスポット測光となる。中央重点測光方式
の場合、画面の中央部が最大であるような重み付けをす
ることもよく行われるが、これを行うには第３図に示す
ような、単なるゲートでは実現できず、例えば乗算機を
用い。Now, the light incident from the subject passes through the lens 101, the iris 102 appropriately limits the amount of light, and the light enters the image sensor 103.
reach. Then, depending on the light of the subject, the image sensor 1
A signal voltage (current) is obtained from 03, amplified by a linear amplifier 104, and guided to a subsequent process circuit. The output signal of the amplifier 104 is used to determine a photometric frame within the screen by a gate circuit 340 controlled by a gate signal generator 350, and only the signals within this photometric frame are guided to an integrator 330 for integration. The integrated signal is compared with a reference level 1B2 in a comparison 5181, and its output controls the iris 102 via the iris drive circuit 112. At that time, if the gain of the comparator is sufficiently large, the iris 102 is controlled by this control loop so that the integral value 331 of the video signal within the photometry frame becomes equal to the reference value 182. When the photometry frame determined by the gate 340 covers the entire screen, front average photometry is used, and when the photometry frame is a small area at the center, center-weighted photometry or spot photometry is used. In the case of center-weighted metering, weighting is often done so that the center of the screen is the largest, but this cannot be achieved with a simple gate as shown in Figure 3; for example, a multiplier is required to do this. using.

映像信号とウェイト信号の積を求める必要かある。Is it necessary to find the product of the video signal and the weight signal?

［発明が解決しようとする問題点］ 前記のような従来の測光方式には、次のような問題かあ
る。即ち、第１の前面平均測光の場合、逆光の中の被写
体は逆光部分の輝度か高いため、平均化（積分）した信
号て絞りを制御すると絞りを閉じる方向に働き、その結
果、被写体は黒く沈んてしまう。[Problems to be Solved by the Invention] The conventional photometry method as described above has the following problems. In other words, in the case of the first front average metering, the backlit subject has a high brightness in the backlit area, so when the averaged (integrated) signal is used to control the aperture, it works in the direction of closing the aperture, and as a result, the subject appears black. I feel depressed.

また、暗い背景の前の明るい被写体の場合、映像信号の
平均レベルか低下するのて、絞りを開く方向に働き、被
写体は白くとんでしまうという現象が起こる。Furthermore, in the case of a bright subject in front of a dark background, the average level of the video signal decreases, causing the aperture to open, causing the subject to appear white.

第２の中央重点測光方式の場合は、被写体か画面の中心
部に位置している場合は、被写体に対して最適露光が得
られるが、被写体が中心部を外れると前面平均測光方式
と同じ現象が起こる。即ち、逆光の場合、被写体は黒く
沈み、暗い背景の場合、被写体は白くとんてしまうとい
う現象が起こる。In the case of the second center-weighted metering method, if the subject is located in the center of the screen, the optimal exposure for the subject can be obtained, but if the subject is away from the center, the same phenomenon as in the front-averaged metering method occurs. happens. That is, in the case of backlighting, the subject appears black, and in the case of a dark background, the subject appears white.

本発明はこのような従来の問題点を解決するためになさ
れたもので、被写体の位置と背景とに関係なく、常に最
適露光か得られる撮像装置を提供することを目的とする
。The present invention has been made to solve these conventional problems, and it is an object of the present invention to provide an imaging device that can always obtain optimal exposure regardless of the position of the subject and the background.

［問題点を解決するための手段］ 上記の目的を達成するために、この発明の撮像装置は撮
像素子からの複数の色差信号を取出し、基準値と比較し
て、所定の色成分のレベルに達したか否かを判定する手
段と、この判定結果に応じて映像信号の積分量を変化さ
せて、この変化量に基づいて前記撮像素子の露光量を制
御する手段とを具備した構成を有するものである。[Means for Solving the Problems] In order to achieve the above object, the imaging device of the present invention extracts a plurality of color difference signals from an imaging device, compares them with a reference value, and determines the level of a predetermined color component. It has a configuration comprising means for determining whether or not the image sensor has been reached, and means for changing the integral amount of the video signal according to the result of this determination and controlling the exposure amount of the image sensor based on this amount of change. It is something.

［作用］ 上記の露光機構制御方式により、例えば人物等の肌色を
中心とする色の被写体に対して、常に最適露光量を得る
ようにしたものである。[Function] The above-described exposure mechanism control method always obtains the optimum exposure amount for a subject whose color is mainly skin tone, such as a person, for example.

［実施例］ 第１図は本発明による撮像装置の一実施例を示す図で、
同図において、１０５は増幅された映像信号を処理し、
輝度信号Ｙと色差信号Ｒ−ＹまたはＢ−Ｙ信号を得るプ
ロセス回路、１０６はプロセス回路で得られた輝度信号
と色差信号からＮＴＳＣ，ＰＡＬ等の出力信号を得るエ
ンコーダ、１０７はエンコーダの出力端子、１２１と１
２２はそれぞれ前記色差信号Ｒ−ＹとＢ−Ｙを入力とし
、それぞれ基準レベル１３１．−１３２と比較して出力
する比較器、１４１は前記二つの比較器の出力を入力と
する論理ａ（アンド）回路、１５１は前記アンド回路の
出力で制御されるスイッチ、１６２はプロセス回路１０
５で処理される以前の映像信号の積分器、１６３は前記
スイッチ１５１を介して入力される映像信号を積分する
積分器、１７０は積分器１６２と積分器１６３の出力を
混合する混合器、１８１は前記混合器１７０の出力を基
準電圧１Ｂ２と比較する比較器、１１２は比較器１８１
の出力により、アイリス１０２を駆動するための駆動回
路を表わしている。また、第３図と同一符号は同一また
は相当部分を示す。[Embodiment] FIG. 1 is a diagram showing an embodiment of an imaging device according to the present invention.
In the figure, 105 processes the amplified video signal;
A process circuit that obtains a luminance signal Y and a color difference signal R-Y or B-Y; 106 is an encoder that obtains an output signal such as NTSC or PAL from the luminance signal and color difference signal obtained by the process circuit; 107 is an output terminal of the encoder , 121 and 1
22 receives the color difference signals R-Y and B-Y, respectively, and receives the reference level 131.22, respectively. 141 is a logic a (AND) circuit which inputs the outputs of the two comparators, 151 is a switch controlled by the output of the AND circuit, and 162 is a process circuit 10.
163 is an integrator that integrates the video signal input through the switch 151; 170 is a mixer that mixes the outputs of the integrator 162 and the integrator 163; 181 112 is a comparator that compares the output of the mixer 170 with the reference voltage 1B2, and 112 is a comparator 181.
This represents a drive circuit for driving the iris 102 by the output of the iris 102. Further, the same reference numerals as in FIG. 3 indicate the same or corresponding parts.

第１図の回路において、被写体の光はレンズｌｏｔを介
して入射し、アイリス１０２で光量が最適に制御されて
撮像素子１０３に到達する。平面上に配列された撮像素
子１０３の各画素からは被写体の対応する像点からの入
射光量に比例した電気信号か取出される。これを増幅し
てプロセス回路１０５に加え、ガンマ補正等を行ったの
ち、プロセス回路ｌＯ５内のマトリクス回路で輝度信号
Ｙと色差信号Ｒ−Ｙ、Ｂ−Ｙを作り出す。色差信号Ｒ−
Ｙの値を比較器１２１で基準値１３１の値と比較し、色
差信号Ｒ−Ｙの値が正のとき出力が高いレベルになり、
負のとき出力が低レベルになる。また、色差信号Ｂ−Ｙ
の値を比較器１２２で基準値１３２と比較し、色差信号
Ｂ−Ｙの値が負のとき出力か高レベルになり、正のとき
低レベルとなる。これら比較器１２１，１２２の出力が
（１）共に高レベルのとき、アンド回路１４１の出力も
高レベルとなり、スイッチ１５１を閉じ、プロセス前の
輝度信号１９０を積分器１６３に供給し、同時にスイッ
チ１５２を開き、プロセス前の輝度信号１９０の精分器
１６２への供給を止める。また、（ｉｉ）共に高レベル
ではないとき、アンド回路の出力は低レベルとなり、ス
イッチ１５１を開いて輝度信号１９０を精分器１６３へ
供給することを止め、同時にスイッチ１５２を閉じて輝
度信号１９０を積分器１６２へ供給し、積分する。In the circuit shown in FIG. 1, light from a subject enters through a lens lot, and the amount of light is optimally controlled by an iris 102 before reaching an image sensor 103. Electric signals proportional to the amount of incident light from the corresponding image point of the object are extracted from each pixel of the image sensor 103 arranged on a plane. After amplifying this and applying it to the process circuit 105 and performing gamma correction etc., a luminance signal Y and color difference signals RY and BY are generated by a matrix circuit in the process circuit IO5. Color difference signal R-
The value of Y is compared with the value of the reference value 131 by the comparator 121, and when the value of the color difference signal RY is positive, the output becomes a high level,
When negative, the output is low level. In addition, the color difference signal B-Y
The value of the color difference signal B-Y is compared with a reference value 132 by a comparator 122, and when the value of the color difference signal B-Y is negative, the output becomes high level, and when it is positive, the output becomes low level. When the outputs of these comparators 121 and 122 (1) are both high level, the output of the AND circuit 141 also becomes high level, the switch 151 is closed, the luminance signal 190 before processing is supplied to the integrator 163, and at the same time the switch 152 is opened and the supply of the pre-process brightness signal 190 to the separator 162 is stopped. (ii) When both are not at high level, the output of the AND circuit becomes low level, the switch 151 is opened to stop supplying the luminance signal 190 to the separator 163, and at the same time, the switch 152 is closed and the luminance signal 190 is is supplied to the integrator 162 and integrated.

−Ｌに述べた、色差信号を検出して、各積分器１６２．
１６３へ輝度信号１９０を供給する処理は肌色に近い色
を含んでいる被写体の輝度情報を選択するためである。-L, each integrator 162.
The purpose of the process of supplying the luminance signal 190 to the luminance signal 163 is to select luminance information of a subject that includes a color close to the skin color.

第２図は色差信号座標軸における肌色の位置と、その属
する象限を示した図で、２０１は肌色を含む色差信号座
標上の象限、２０２は肌色の座標て、縦軸はＲ−Ｙを、
横軸はＢ−Ｙを示している。第２図において、色差信号
Ｒ−Ｙか正て色差信号Ｂ−Ｙか負の象限に肌色が存在す
る。FIG. 2 is a diagram showing the position of skin color on the color difference signal coordinate axis and the quadrant to which it belongs. 201 is the quadrant on the color difference signal coordinate that includes the skin color, 202 is the coordinate of the skin color, and the vertical axis is R-Y.
The horizontal axis indicates BY. In FIG. 2, skin color exists in the negative quadrant of the color difference signal RY, the positive color difference signal B-Y, and the negative quadrant.

従って、上記処理を行うと黄色から赤までの色の被写体
の場合の輝度信号が、積分器１６３て積分され、それ以
外の色及び無彩色の輝度信号は積分器１６２で積分され
る。従って、例えば、混合器１７０て積分器１６３の出
力の比重を大きく、積分器１６２の出力の比重を小さく
混合して比較器１８１に導くことにより、肌色を含む象
限の色を優先してアイリスを制御することかできる。Therefore, when the above processing is performed, the luminance signals for subjects of colors from yellow to red are integrated by the integrator 163, and the luminance signals of other colors and achromatic colors are integrated by the integrator 162. Therefore, for example, by mixing the output of the integrator 163 with a higher specific gravity and the output of the integrator 162 with a lower specific gravity and guiding the mixture to the comparator 181, for example, the iris can be adjusted with priority given to the color in the quadrant that includes the skin tone. Can be controlled.

［発明の効果］ 以上説明したように、本発明によれば、特に黄色から赤
までの肌色を中心とする色の被写体に対して、常に最適
な露光量が得られるという効果がある。[Effects of the Invention] As described above, according to the present invention, there is an effect that the optimum exposure amount can always be obtained especially for subjects whose colors are mainly skin tones from yellow to red.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の撮像装置における一実施例を示す図、
第２図は色差信号座標上の肌色の位置と肌色を含む象限
を示す図、第３図は従来の撮像装置の主要部を概略を示
した図である。 図中。 １０１：レンズ　　１０２ニアイリス １ａ３：撮像素子　　　　１ａ４：増Ｉ！ａ器１０５：
プロセス回路　　１０６：エンコーダ１２１、■２２，
１８１：比較器　１４１：アンド回路１５１．１５２：
スイッチ　　１６２，１６３：ｆｆ１分器１７０：混合
器　　　　　１１２：駆動回路代理人　弁理士　１）北
　嵩　晴FIG. 1 is a diagram showing an embodiment of the imaging device of the present invention,
FIG. 2 is a diagram showing the position of skin color on color difference signal coordinates and a quadrant including the skin color, and FIG. 3 is a diagram schematically showing the main parts of a conventional imaging device. In the figure. 101: Lens 102 Near iris 1a3: Image sensor 1a4: Increase I! A device 105:
Process circuit 106: Encoder 121, ■22,
181: Comparator 141: AND circuit 151.152:
Switch 162, 163: ff1 divider 170: Mixer 112: Drive circuit agent Patent attorney 1) Haru Kitatake

Claims (1)

【特許請求の範囲】[Claims] 被写体像を光学系を介して撮像素子に結像させて映像信
号を出力させる撮像装置において、前記撮像素子からの
複数の色差信号を取出し、基準値と比較して、所定の色
成分のレベルに達したか否かを判定する手段と、この判
定結果に応じて映像信号の積分量を変化させて、この変
化量に基づいて前記撮像素子の露光量を制御する手段と
を具備したことを特徴とする撮像装置。In an imaging device that focuses a subject image on an imaging device via an optical system and outputs a video signal, a plurality of color difference signals are extracted from the imaging device, and compared with a reference value to determine a predetermined color component level. It is characterized by comprising means for determining whether or not the amount of light has been reached, and means for changing the integral amount of the video signal according to the result of this determination and controlling the exposure amount of the image sensor based on this amount of change. An imaging device that uses