JPH0479692A - White balance controller - Google Patents
White balance controllerInfo
- Publication number
- JPH0479692A JPH0479692A JP2193010A JP19301090A JPH0479692A JP H0479692 A JPH0479692 A JP H0479692A JP 2193010 A JP2193010 A JP 2193010A JP 19301090 A JP19301090 A JP 19301090A JP H0479692 A JPH0479692 A JP H0479692A
- Authority
- JP
- Japan
- Prior art keywords
- white
- color
- signal
- white balance
- luminance
- 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.)
- Granted
Links
- 238000001514 detection method Methods 0.000 claims description 11
- 238000000926 separation method Methods 0.000 claims description 3
- 238000003384 imaging method Methods 0.000 claims description 2
- 238000000605 extraction Methods 0.000 abstract description 23
- 238000005286 illumination Methods 0.000 abstract description 4
- 230000003044 adaptive effect Effects 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 4
- 239000011159 matrix material Substances 0.000 description 4
- 238000012935 Averaging Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 101100334009 Caenorhabditis elegans rib-2 gene Proteins 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000004570 mortar (masonry) Substances 0.000 description 2
- 230000005457 Black-body radiation Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 230000005021 gait Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/64—Circuits for processing colour signals
- H04N9/73—Colour balance circuits, e.g. white balance circuits or colour temperature control
Abstract
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などの撮像装置にかかり、特に光
源の色温度変化に際して安定なホワイトバランス制御を
提供する装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imaging device such as a video camera, and more particularly to a device that provides stable white balance control when the color temperature of a light source changes.
従来この種の装置は、特開昭６３−２１９２９１号公報
に記載のように白バランス調整後の色差信号（または該
信号を演算した信号）の振幅に対して固定間い値によっ
て白抽出を行っていた。Conventionally, this type of device performs white extraction using a fixed interval value for the amplitude of a color difference signal (or a signal obtained by calculating this signal) after white balance adjustment, as described in Japanese Patent Application Laid-Open No. 63-219291. was.
上記従来技術はホワイトバランスのとれた状態での有色
部分の彩度のみに着目しており照明の色温度状態に関し
ては考慮されていなかった。The above-mentioned conventional technology focuses only on the saturation of colored parts in a white balanced state, and does not take into account the color temperature state of the illumination.
本発明の目的は、被写体の彩度情報と照明の色温度また
はホワイトバランスの調整状態とを組み合わせることに
より適切な白抽出範囲の設定を行うことにある。An object of the present invention is to set an appropriate white extraction range by combining the saturation information of a subject and the color temperature of illumination or the adjustment state of white balance.
また上記従来技術は画面中の臼孔率に対する自動露光制
御特性や撮像素子感度に関してはあまり考慮されておら
ず、撮影する被写体や照度によっては検出レベルが不適
正となることがあった。Further, the above-mentioned conventional technology does not give much consideration to the automatic exposure control characteristics for the porosity in the screen or the sensitivity of the image sensor, and the detection level may become inappropriate depending on the subject to be photographed or the illuminance.
本発明の他の目的は、撮影条件の変化に応じて常に適確
な白抽出を達成することにある。Another object of the present invention is to always achieve accurate white extraction in response to changes in photographing conditions.
〔課題を解決するための手段〕
上記目的を達成するために、照明の色温度またはホワイ
トバランス制御状態に追従して白とみなす範囲（色種、
彩度）を適応させるようにした。[Means for solving the problem] In order to achieve the above objective, the range that is considered white (color type,
The color saturation) is now adapted.
上記他の目的を達成するために、撮影画面の輝度分布等
に追従して白とみなす範囲（濃淡、明暗）を適応させる
ようにした。In order to achieve the other objectives mentioned above, the range (shade, light and dark) that is considered white is adapted to follow the brightness distribution of the photographic screen.
白抽出範囲がホワイトバランス初期状態に対して定めら
れている場合臼として抽出される彩度の範囲は常に一定
であるが白の色温度変化といった観点からはホワイトバ
ランスの状態によって変化することになる。例えば初期
状態５０００°Ｋに対して１００００°Ｋまでを白とみ
なすよう設定した場合８０００°ｋにてホワイトバラン
スがとれた状態では２００００’ Ｋでも白とみなして
しまうことになり、逆に低色温度側の抽出範囲は狭くな
る。そこでホワイトバランスの調整状態に応じて前記臼
の抽出範囲をシフトするようにした。これは例えば高色
温度でホワイトバランスが会っているときは赤方向（Ｒ
−Ｂの正方向）の白抽出範囲を広く、青方向（Ｒ−Ｂの
負方向）の白抽出範囲は狭くなるよう動作する。If the white extraction range is determined based on the initial state of white balance, the range of saturation extracted as a mortar is always constant, but from the perspective of changes in white color temperature, it will change depending on the state of white balance. . For example, if you set the initial state of 5000°K to consider white up to 10000°K, if the white balance is set at 8000°K, even 20000°K will be considered white, and conversely, low color The extraction range on the temperature side becomes narrower. Therefore, the extraction range of the mortar is shifted depending on the white balance adjustment state. For example, when the color temperature is high and the white balance is matched, this will change towards red (R).
-The white extraction range in the positive direction of B is widened, and the white extraction range in the blue direction (negative direction of R-B) is narrowed.
また逆に低色温度でホワイトバランスが会っているとき
は赤方向（Ｒ−Ｈの正方向）の白抽出範囲を狭く、青方
向（Ｒ−Ｂの負方向）の白抽出範囲は広くなるよう動作
する。Conversely, when the color temperature is low and the white balance is matched, the white extraction range in the red direction (positive direction of R-H) will be narrowed, and the white extraction range in the blue direction (negative direction of R-B) will be widened. Operate.
これにより撮影時の照明の色温度（ホワイトバランスの
調整状態）に選らず白抽出の対象となる色温度範囲が一
定に保たれるのでより安定かつ厳密な白抽出が可能にな
る。As a result, the color temperature range from which white is extracted remains constant regardless of the color temperature of the lighting at the time of shooting (white balance adjustment state), making it possible to perform more stable and precise white extraction.
一般に、被写体の白色部は有彩色部に比べ光の反射率が
高く、従って白い部分と色のついた部分が混在している
場合比較的高輝度の部分は白とみなすことができる。そ
こで例えば輝度の全体平均を閾い値とし、それ以上を白
として抽出する。これにより、′比較的”高輝度といっ
た検出ができるので画面全体の輝度変動や、照明不足な
どで規定の輝度が得られないような場合でも検出の安定
化が図れる。Generally, white parts of an object have a higher light reflectance than chromatic parts, so when white parts and colored parts coexist, relatively high-luminance parts can be regarded as white. Therefore, for example, the overall average brightness is set as a threshold value, and anything above that value is extracted as white. This makes it possible to detect ``relatively'' high brightness, so that detection can be stabilized even when a specified brightness cannot be obtained due to fluctuations in the brightness of the entire screen or insufficient lighting.
以下、本発明の一実施例を第１図により説明する０色分
離手段２は撮像素子１より出力された信号から輝度、色
信号を生成する。赤（Ｒ）、青（Ｂ）色信号はそれぞれ
利得制御回路３ｒ、３ｂを経た後マトリクス回路４にて
輝度（Ｙ）信号と組み会わされ色差信号（Ｒ−Ｙ、Ｂ−
Ｙ）が生成される。該生成された輝度（Ｙ）及び色差信
号（Ｒ−Ｙ、Ｂ−Ｙ）は出力される一方ホワイドバラン
ス制御系へ入力される。該制御系では前記の輝度、色差
信号を用いて撮影画面中の白色部を検出し、ホワイトバ
ランスを合わせるための信号を生成、前記Ｒ，Ｂ信号経
路中の利得制御回路３ｒ。Hereinafter, one embodiment of the present invention will be described with reference to FIG. 1. The zero color separation means 2 generates luminance and color signals from the signal output from the image sensor 1. The red (R) and blue (B) color signals pass through gain control circuits 3r and 3b, respectively, and then are combined with the luminance (Y) signal in the matrix circuit 4 to produce color difference signals (R-Y, B-
Y) is generated. The generated luminance (Y) and color difference signals (R-Y, B-Y) are output and input to the white balance control system. The control system uses the luminance and color difference signals to detect a white part in the photographic screen and generates a signal for adjusting the white balance, and a gain control circuit 3r in the R and B signal paths.
３ｂに帰還する。Return to 3b.
以下１本実施例における制御系の動作につき詳しく説明
する。カメラ信号処理系より取り出された色差信号（Ｒ
−Ｙ、Ｂ−Ｙ）はそれぞれ加算６、減算５され色温度変
化及びＲ←→Ｂ方向の彩度検出信号Ｒ−ＢとＭｇ←→Ｇ
方向の彩度検出信号Ｒ＋Ｂ−２Ｙ信号が生成される。前
記２つの信号（Ｒ−Ｂ、Ｒ＋Ｂ−２Ｙ）はそれぞれゲー
ト回路（７１，７２）にて白色部の信号のみが取り出さ
れた後画面全体で積分・平均化（８１，８２）され、こ
の撮影画面の色調（ホワイトバランスのずれ）に相当す
る白色部平増化Ｒ−Ｂ（ＲＩＢ−２Ｙ）信号に応じ、比
較増幅回路９１．９２にてホワイトバランス制御信号が
生成される。尚前記比較増幅回路９１．９２のもう片方
に入力される比較基準電圧はホワイトバランスのとれた
状態での白色部平増化Ｒ−Ｂ （ＲＩＢ−２Ｙ）信号に
相当する。前記増幅回路９１より出力されたＲ−Ｂ軸方
向の制御信号と増幅回路９２より出力されたＲＩＢ−２
Ｙ軸方向の制御信号はこの例ではＷＢマトリクス１１に
おいて赤（Ｒ）、青（Ｂ）信号利得制御用の信号に変換
され、それぞれ前記利得制御回路３ｒ、３ｂを制御する
ことにより、ホワイトバランスの調整が行われる。白色
部抽出用の前記ゲート回路７１．７２を駆動する白色部
検出手段１０は、前記２つの彩度検出信号（Ｒ−Ｂ、Ｒ
ＩＢ−２Ｙ）と輝度信号（Ｙ）より低彩度かつ高輝度部
分の検出を行う。ところで黒体輻射に従う色温度変化（
自然光の色質変化）の軌跡は色差平面上では第２図に示
す位置に表わされ、前記Ｒ−Ｂ。The operation of the control system in this embodiment will be explained in detail below. Color difference signal (R
-Y, B-Y) are respectively added 6 and subtracted 5 to detect color temperature change and R←→B direction saturation detection signals R-B and Mg←→G
A direction saturation detection signal R+B-2Y signal is generated. The two signals (R-B, R+B-2Y) are each extracted by a gate circuit (71, 72) in which only the signal of the white part is extracted, and then integrated and averaged (81, 82) over the entire screen. A white balance control signal is generated in comparison amplifier circuits 91 and 92 in accordance with a white area normalized R-B (RIB-2Y) signal corresponding to the screen color tone (white balance deviation). The comparison reference voltage inputted to the other side of the comparison amplifier circuits 91 and 92 corresponds to the white part normalized R-B (RIB-2Y) signal in a white balanced state. The control signal in the R-B axis direction output from the amplifier circuit 91 and the RIB-2 output from the amplifier circuit 92
In this example, the control signal in the Y-axis direction is converted into red (R) and blue (B) signal gain control signals in the WB matrix 11, and the white balance is controlled by controlling the gain control circuits 3r and 3b, respectively. Adjustments will be made. The white portion detection means 10 that drives the gate circuits 71 and 72 for white portion extraction receives the two saturation detection signals (R-B, R
IB-2Y) and the luminance signal (Y) to detect low chroma and high luminance parts. By the way, color temperature change according to blackbody radiation (
The trajectory of the change in color quality of natural light is represented on the color difference plane at the position shown in FIG.
ＲＩＢ−２Ｙ軸との関係は図示のとうりである。The relationship with the Y axis of RIB-2 is as shown in the figure.
即ち該Ｒ−Ｂにて光源の色温度変化による白（Ｒ−Ｙ、
Ｂ−Ｙ軸の交点）からのずれを、ＲＩＢ−２Ｙにて色温
度変化以外の理由による白からのずれを知ることができ
る。そこで上述の白抽出（白とみなす）範囲の設定を、
少なくとも実用的な色温度変化（例えば２０００°に〜
１００００°Ｋ）の補正は可能とするため、該色温度変
化による白の着色を彩度にあてはめ図中−点鎖線で囲ま
れた部分としておく。That is, white (R-Y,
With the RIB-2Y, it is possible to know the deviation from white (the intersection point of the BY axis) and the deviation from white due to reasons other than color temperature changes. Therefore, the settings for the white extraction range (regarded as white) described above are
at least a practical color temperature change (e.g. ~2000°)
10,000°K), the white coloring caused by the color temperature change is applied to the saturation, and the area surrounded by the dotted chain line in the figure is shown.
（初期状態）この状態から照明の色温度が変化したとす
ると上述のような設定下では２０００°Ｋ（または１０
０００°Ｋ）までの変化に相当する彩度までは白とみな
され、白色部がＲ−Ｂ＝Ｏ（ＲＩＢ −２Ｙ＝Ｏ）とな
る様ホワイトバランス制御がなされる。この時ホワイト
バランス制御信号（増幅回路９１出力）は照明の色温度
変化に応じて変化するのでホワイトバランス収束後の前
記制御信号からその時の色温度値を推することができる
。また前述のように実用的な色温度範囲を制限した場合
、例えば２０００°にでホワイトバランスが合っていれ
ばそれ以下の色温度にはならないと仮定でき、よってこ
の状態で赤方向に振幅をもつ信号は全て有彩色であると
考えて良い。即ち低色温度下での白抽出範囲は歩測に関
しては前述の初期状態の設定より更に低彩度に限って良
く、逆に背側に関しては高彩度方向に広げる必要が生ず
。第３図はこの低色温度下での撮影における白抽出範囲
（−点鎖線）を示したものである。このようにその時点
におけるホワイトバランス制御信号（制御状態）に応じ
て白とみなす彩度レベルを変えることにより、常に適正
な白抽出範囲を設定できる効果がある。更に本実施例で
は色温度変化方向の変更についてのみ記したが、同様の
制御をＭｇ−Ｇ方向（ＲＩＢ−２Ｙ軸）に対して行えば
より効果が上がる。(Initial state) If the color temperature of the lighting changes from this state, under the above settings it will be 2000°K (or 100°K).
A saturation corresponding to a change up to 000°K) is considered white, and white balance control is performed so that the white portion satisfies R-B=O (RIB-2Y=O). At this time, since the white balance control signal (output of the amplifier circuit 91) changes according to the change in color temperature of the illumination, the color temperature value at that time can be estimated from the control signal after the white balance has converged. Furthermore, if we limit the practical color temperature range as mentioned above, it can be assumed that if the white balance is correct at, for example, 2000°, the color temperature will not be lower than that. All signals can be considered to be chromatic. That is, the white extraction range under a low color temperature can be limited to a lower chroma than the above-mentioned initial state setting in terms of gait measurement, and conversely, it is not necessary to widen the range toward higher chroma for the dorsal side. FIG. 3 shows the white extraction range (-dotted chain line) in photography under this low color temperature. In this way, by changing the saturation level that is considered white according to the white balance control signal (control state) at that time, there is an effect that an appropriate white extraction range can always be set. Further, in this embodiment, only the change in the direction of color temperature change has been described, but if similar control is performed in the Mg-G direction (RIB-2Y axis), the effect will be even greater.
次に本発明の他の実施例について第４図により説明する
。本実施例は白抽出における輝度信号の利用法に関する
ものである。全体構成ならびに各部の動作は前記第１実
施例と同様である。上述のように白抽出は低彩度、高輝
度部を白とみなし核部の信号を取り出すよう動作するが
、この白とみなす輝度レベルを固定した場合、白色部と
有色部の比率によっては自動露光制御等の動作によって
有色部の輝度レベルが上昇したり、逆に照度が不足して
いる場合には全体の輝度レベルが低下するなどの現象に
より白抽出が不適切となることがある。本実施例では信
号系より取り比された輝度（Ｙ）信号は平均化手段１２
により生成された平均値と比較１３され、該比較結果に
より白抽出がなされる。これにより、上述のような撮影
状態の変動に際しても「比較的」高輝度なる条件で安定
な白検出が達成できる。またこの例では比較値を平均化
により生成しているが、輝度の最大値付近を検出するよ
う例えばピーク輝度の８０％を比較値として生成するよ
うな構成としても良い。Next, another embodiment of the present invention will be described with reference to FIG. This embodiment relates to a method of using a luminance signal in white extraction. The overall configuration and operation of each part are the same as in the first embodiment. As mentioned above, white extraction treats low chroma and high brightness areas as white and extracts the core signal. However, if the brightness level that is considered white is fixed, depending on the ratio of white areas to colored areas, white extraction may occur automatically. White extraction may become inappropriate due to phenomena such as an increase in the brightness level of a colored part due to an operation such as exposure control, or a decrease in the overall brightness level when illuminance is insufficient. In this embodiment, the luminance (Y) signal obtained from the signal system is sent to the averaging means 12.
It is compared with the average value generated by 13, and white extraction is performed based on the comparison result. As a result, stable white detection can be achieved under conditions of "relatively" high brightness even when the photographing conditions change as described above. Further, in this example, the comparison value is generated by averaging, but a configuration may be adopted in which, for example, 80% of the peak luminance is generated as the comparison value so as to detect the vicinity of the maximum value of luminance.
尚上述のような制御を精度よく行なうには、ある程度微
妙な信号管理を要するが、例えばディジタル信号処理を
用いることによってソフト等により容易に対応可能であ
る。In order to perform the above-mentioned control with high precision, a certain degree of delicate signal management is required, but this can be easily handled by software, for example, by using digital signal processing.
本発明によれば、各撮影時点での色温度や照明の種類等
によるホワイトバランスの状態に適応した彩度レベルと
照度や淡い色（白）の比率などによる露出の状態に適応
した輝度レベルとによって白抽出が行われるので、撮影
条件の変化にたいしてホワイトバランス制御の安定化及
び誤動作の軽減に効果がある。According to the present invention, the saturation level is adapted to the white balance state depending on the color temperature and type of lighting at each shooting time, and the brightness level is adapted to the exposure state depending on the illuminance and ratio of light color (white). Since white extraction is performed using the above method, it is effective in stabilizing white balance control and reducing malfunctions in response to changes in photographing conditions.
晶は本発明の一実施例を示すブロック構成図、第２図、
第３図は第１図に示すホワイトバランス制御装置の動作
説明図、第４図は本発明の他の実施例を示すブロック構
成図である。
符号の説明
１・・・撮像素子、 ２・・・色分離手段、３ｒ
、３ｂ・・・利得制御回路、
４・・・マトリクス（色差信号生成手段）、５・・・減
算、 ６・・・加算、７１・７２・・・ゲート、８１・
８２・・・積分、
９１・９２・・・増幅（ホワイトバランス制御信号生成
手段）
１０・・・白色部検出手段。
１２・・・平均化手段、
１１・・・ＷＢマトリクス。
１３・・・比較手段。
纂
！
図Figure 2 is a block diagram showing an embodiment of the present invention;
FIG. 3 is an explanatory diagram of the operation of the white balance control device shown in FIG. 1, and FIG. 4 is a block diagram showing another embodiment of the present invention. Explanation of symbols 1...Image sensor, 2...Color separation means, 3r
, 3b... Gain control circuit, 4... Matrix (color difference signal generation means), 5... Subtraction, 6... Addition, 71.72... Gate, 81.
82... Integration, 91.92... Amplification (white balance control signal generation means) 10... White portion detection means. 12... Averaging means, 11... WB matrix. 13...Comparison means. Complete! figure
Claims (1)
号を生成する色分離手段（２）と該手段により分離され
た色信号のうち少なくとも２つの色信号の利得を制御す
る手段（３ｒ、３ｂ）と前記色および／または輝度信号
から色差信号を生成する手段（４）とからなるビデオカ
メラなどの撮像装置において、 前記色差信号、色信号などを用いて撮影被写体中の白色
および／または無彩色部を検出する手段（１０）と撮影
画面のホワイトバランスずれを検出する手段（９１、９
２）と該検出結果に応じて前記色信号の利得を制御する
手段を帰還制御し白調整を行うよう構成されたホワイト
バランス制御装置であり、 撮影中の光源の色温度に応じて、前記白色部検出手段に
おいての白とみなす範囲を適宜変更する手段を設けたこ
とを特徴とするホワイトバランス制御装置。 ２、前記撮影中の光源の色温度は、前記白調整の際の前
記色信号の利得制御量を用いて検出することを特徴とす
る請求項１記載のホワイトバランス制御装置。 ３、輝度信号を用いて撮影被写体中の白色部を検出する
手段（１０）あり、画面中の比較的高輝度の部分を白と
みなすよう構成された白色検出手段において、 高輝度か否かを判断する比較閾い値を前記輝度信号を用
いて生成、もしくは平均レベルや分布状態に応じて変更
する手段（１２）を設けたことを特徴とするホワイトバ
ランス制御装置。[Claims] 1. An image sensor (1), a color separation means (2) for generating a luminance signal and a color signal from the output of the element, and gains of at least two color signals among the color signals separated by the means. In an imaging device such as a video camera, comprising means (3r, 3b) for controlling the color difference signal and means (4) for generating a color difference signal from the color and/or luminance signal, the color difference signal, color signal, etc. means (10) for detecting white and/or achromatic parts in the photographic screen; and means (91, 9) for detecting white balance deviation of the photographic screen;
2) and a white balance control device configured to perform white adjustment by performing feedback control on a means for controlling the gain of the color signal according to the detection result, and the white balance control device is configured to perform white adjustment by performing feedback control on a means for controlling the gain of the color signal according to the detection result; 1. A white balance control device comprising means for appropriately changing a range considered as white in a portion detection means. 2. The white balance control device according to claim 1, wherein the color temperature of the light source during photographing is detected using a gain control amount of the color signal during the white adjustment. 3. There is a means (10) for detecting a white part in a photographed subject using a luminance signal, and in the white detecting means configured to regard a relatively high-luminance part of the screen as white, it is possible to detect whether or not it is high-luminance. A white balance control device comprising means (12) for generating a comparison threshold value for judgment using the luminance signal or for changing it according to an average level or a distribution state.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2193010A JP2776965B2 (en) | 1990-07-23 | 1990-07-23 | Imaging device |
| US07/731,531 US5177599A (en) | 1990-07-23 | 1991-07-17 | White balance controller for an image pick-up apparatus including an abnormality detector |
| KR1019910012492A KR940002610B1 (en) | 1990-07-23 | 1991-07-22 | White balance controller for an image pick-up apparatus including an abnormality detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2193010A JP2776965B2 (en) | 1990-07-23 | 1990-07-23 | Imaging device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0479692A true JPH0479692A (en) | 1992-03-13 |
| JP2776965B2 JP2776965B2 (en) | 1998-07-16 |
Family
ID=16300697
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2193010A Expired - Lifetime JP2776965B2 (en) | 1990-07-23 | 1990-07-23 | Imaging device |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2776965B2 (en) |
| KR (1) | KR940002610B1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04373391A (en) * | 1991-06-24 | 1992-12-25 | Akai Electric Co Ltd | Detection of white in white balance circuit |
| JPH057370A (en) * | 1991-06-26 | 1993-01-14 | Akai Electric Co Ltd | Color temperature range detection circuit for white balance circuit |
| US7084880B2 (en) | 2001-07-27 | 2006-08-01 | Hitachi, Ltd. | Video display device and color temperature correction method for the same |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6490693A (en) * | 1987-10-01 | 1989-04-07 | Sony Corp | White balance correcting circuit |
| JPH0294790A (en) * | 1988-09-30 | 1990-04-05 | Toshiba Corp | White balance control circuit |
-
1990
- 1990-07-23 JP JP2193010A patent/JP2776965B2/en not_active Expired - Lifetime
-
1991
- 1991-07-22 KR KR1019910012492A patent/KR940002610B1/en not_active IP Right Cessation
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6490693A (en) * | 1987-10-01 | 1989-04-07 | Sony Corp | White balance correcting circuit |
| JPH0294790A (en) * | 1988-09-30 | 1990-04-05 | Toshiba Corp | White balance control circuit |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04373391A (en) * | 1991-06-24 | 1992-12-25 | Akai Electric Co Ltd | Detection of white in white balance circuit |
| JPH057370A (en) * | 1991-06-26 | 1993-01-14 | Akai Electric Co Ltd | Color temperature range detection circuit for white balance circuit |
| US7084880B2 (en) | 2001-07-27 | 2006-08-01 | Hitachi, Ltd. | Video display device and color temperature correction method for the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2776965B2 (en) | 1998-07-16 |
| KR920003788A (en) | 1992-02-29 |
| KR940002610B1 (en) | 1994-03-26 |
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