JPH0824375B2 - White balance correction circuit - Google Patents
White balance correction circuitInfo
- Publication number
- JPH0824375B2 JPH0824375B2 JP63009838A JP983888A JPH0824375B2 JP H0824375 B2 JPH0824375 B2 JP H0824375B2 JP 63009838 A JP63009838 A JP 63009838A JP 983888 A JP983888 A JP 983888A JP H0824375 B2 JPH0824375 B2 JP H0824375B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- average value
- color
- white balance
- signal
- 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 - Fee Related
Links
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の簡易な白バランス補正回路に
関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple white balance correction circuit for a video camera.
従来の技術 近年、カメラ一体型ビデオの需要の拡大に伴い、低価
格、高性能のカメラ一体型ビデオが求められるようにな
り、商品価値の一要素であるフルオート白バランスに対
しても、より低価格、高性能の白バランス補正回路が要
求されるようになってきた。以下、図面を参照しながら
従来の白バランス補正回路について説明する。2. Description of the Related Art In recent years, with the increasing demand for integrated camera video, low-priced, high-performance integrated camera video has been demanded, and even for full-auto white balance, which is one factor of product value, A low-cost, high-performance white balance correction circuit has been required. A conventional white balance correction circuit will be described below with reference to the drawings.
第３図はこの白バランス補正回路のブロック図を示し
たものであり、１はＲ−Ｙ色差信号11の色差平均値12を
検出するＲ−Ｙ平均値検出回路であり、２は色差平均値
12と白バランス基準値13とを比較し、白バランス補正値
14を出力するＲ−Ｙ平均値比較回路である。４は白バラ
ンス補正値14により第１の色信号16を利得制御する利得
制御回路であり、５は利得制御された色信号17と第３の
色信号18とから前記Ｒ−Ｙ色差信号11を作成するＲ−Ｙ
色差回路である。FIG. 3 is a block diagram of the white balance correction circuit, in which 1 is an RY average value detection circuit for detecting the color difference average value 12 of the RY color difference signal 11, and 2 is the color difference average value.
12 and the white balance reference value 13 are compared, and the white balance correction value
It is an RY average value comparison circuit that outputs 14. Reference numeral 4 denotes a gain control circuit for controlling the gain of the first color signal 16 by the white balance correction value 14, and 5 denotes the RY color difference signal 11 from the gain-controlled color signal 17 and the third color signal 18. Create RY
It is a color difference circuit.
Ｂ−Ｙ色差信号21に対しても同一の信号処理を行なっ
ており、６はＢ−Ｙ色差信号21の色差平均値22を検出す
るＢ−Ｙ平均値検出回路であり、７は色差平均値22と白
バランス基準値23とを比較し、白バランス補正値24を出
力するＢ−Ｙ平均値比較回路である。９は白バランス補
正値24により第２の色信号19を利得制御する利得制御回
路であり、10は利得制御された色信号20と第３の色信号
18とから前記Ｂ−Ｙ色差信号21を作成するＢ−Ｙ色差回
路である。The same signal processing is performed for the BY color difference signal 21, 6 is a BY average value detection circuit for detecting the color difference average value 22 of the BY color difference signal 21, and 7 is the color difference average value. 22 is a BY average value comparison circuit that compares the white balance reference value 23 with the white balance reference value 23 and outputs the white balance correction value 24. Reference numeral 9 is a gain control circuit that controls the gain of the second color signal 19 by the white balance correction value 24, and 10 is the gain-controlled color signal 20 and the third color signal.
18 is a BY color difference circuit for generating the BY color difference signal 21 from 18 and.
以上のように構成された従来の白バランス補正回路に
ついて、白バランス補正動作を説明する。今、基準色温
度においてのＲ−Ｙ色差信号11の白バランスは白バラン
ス基準値13の設定により行われる。同様にＢ−Ｙ色差信
号21の白バランスは白バランス基準値23の設定により行
われる。この状態から色温度が変化した場合、Ｒ−Ｙ色
差信号11が変化し、同時に色差平均値12が変化する。こ
の為、白バランス補正値14が変化する。この白バランス
補正値14の変化は色差平均値12の変化を抑圧する様、色
信号16の利得制御を行う。Ｂ−Ｙ色差信号に対しても同
様に、白バランス補正値24の変化は色差平均値22の変化
を抑圧する様、色信号19の利得制御を行う。以上のよう
に、色温度変化によるＲ−Ｙ色差信号11及びＢ−Ｙ色差
信号22の変化を抑圧する一連の回路動作により、白バラ
ンス補正が行われていた。The white balance correction operation of the conventional white balance correction circuit configured as described above will be described. Now, the white balance of the RY color difference signal 11 at the reference color temperature is performed by setting the white balance reference value 13. Similarly, the white balance of the BY color difference signal 21 is set by setting the white balance reference value 23. When the color temperature changes from this state, the RY color difference signal 11 changes, and at the same time, the color difference average value 12 changes. Therefore, the white balance correction value 14 changes. The gain control of the color signal 16 is performed so that the change of the white balance correction value 14 suppresses the change of the color difference average value 12. Similarly, for the BY color difference signal, the gain control of the color signal 19 is performed so that the change in the white balance correction value 24 suppresses the change in the color difference average value 22. As described above, the white balance correction is performed by a series of circuit operations for suppressing the changes in the RY color difference signal 11 and the BY color difference signal 22 due to the color temperature change.
発明が解決しようとする課題 しかしながら上記のような構成では、色信号16、及
び、色信号19が色成分を含む場合には、この色成分を抑
圧し彩度の減少、又これに伴う色再現の劣化という問題
点を有していた。However, in the above-described configuration, when the color signal 16 and the color signal 19 include a color component, the color component is suppressed to reduce the saturation, and the color reproduction accompanying this is suppressed. It had a problem of deterioration.
本発明はかかる点に鑑み、色成分の抑圧を軽減し、色
再現の劣化を改善する白バランス補正回路を提供するこ
とを目的としている。In view of the above point, the present invention has an object to provide a white balance correction circuit that reduces color component suppression and improves deterioration of color reproduction.
課題を解決するための手段 本発明はＲ−Ｙ色差信号の平均値を求めるＲ−Ｙ平均
値検出回路と、Ｒ−Ｙ平均値と所定値を比較するＲ−Ｙ
平均値比較回路と、Ｂ−Ｙ色差信号の平均値を求めるＢ
−Ｙ平均値検出回路と、Ｂ−Ｙ平均値と所定値を比較す
るＢ−Ｙ平均値比較回路と、Ｒ−Ｙ平均値比較回路の出
力信号とＢ−Ｙ平均値比較回路の出力信号を加算するＲ
−Ｙ加算回路及びＢ−Ｙ加算回路と、Ｒ−Ｙ加算回路の
出力により、第１の色信号を利得制御する利得制御回路
と、Ｂ−Ｙ加算回路の出力により第２の色信号を利得制
御する利得制御回路と、これら二つの利得制御回路の出
力信号とから、Ｒ−Ｙ色差信号及びＢ−Ｙ色差信号を作
成する色差回路を備えた白バランス補正回路である。Means for Solving the Problems The present invention relates to an RY average value detection circuit for obtaining an average value of RY color difference signals and an RY for comparing an RY average value with a predetermined value.
An average value comparison circuit and B for obtaining an average value of BY color difference signals
-Y average value detection circuit, BY average value comparison circuit for comparing the BY average value with a predetermined value, output signal of RY average value comparison circuit and output signal of BY average value comparison circuit R to add
A gain control circuit that controls the gain of the first color signal by the outputs of the -Y addition circuit, the BY addition circuit, and the RY addition circuit; and a gain of the second color signal by the output of the BY addition circuit. It is a white balance correction circuit including a gain control circuit for controlling and a color difference circuit for creating an RY color difference signal and a BY color difference signal from output signals of these two gain control circuits.
作用 本発明は前記した構成により、色温度変化時の白バラ
ンス補正が関連したＲ−Ｙ白バランス補正値とＢ−Ｙ白
バランス補正値とで設定されるようにする事で、色温度
でない色信号入力時には、白バランス補正を行わず、白
バランス補正値の平衡点で補正を安定させる事ができ、
入力色信号の彩度の抑圧を軽減し、色再現を改善するこ
とができる。Effect According to the present invention, the white balance correction when the color temperature changes is set by the related RY white balance correction value and the BY white balance correction value according to the above-described configuration, so that a color not at the color temperature can be obtained. When inputting a signal, the white balance correction is not performed and the correction can be stabilized at the balance point of the white balance correction value.
It is possible to reduce the suppression of the saturation of the input color signal and improve the color reproduction.
実施例 以下、本発明の一実施例の白バランス補正回路につい
て、図面を参照しながら説明する。Embodiment A white balance correction circuit according to an embodiment of the present invention will be described below with reference to the drawings.
第１図は本発明の実施例における白バランス補正回路
のブロック図を示すものであり、第３図に示す従来例に
おける構成ブロックと同一の構成ブロックには同一の符
号を付している。第１図と第３図の異なる点は、白バラ
ンス補正値14と白バランス補正値24を加算する加算回路
３、及び加算回路８を設けている点である。FIG. 1 is a block diagram of a white balance correction circuit according to an embodiment of the present invention. The same constituent blocks as those of the conventional example shown in FIG. 3 are designated by the same reference numerals. The difference between FIGS. 1 and 3 is that an addition circuit 3 and an addition circuit 8 for adding the white balance correction value 14 and the white balance correction value 24 are provided.
上記のように構成された白バランス補正回路につい
て、第２図を参照しながらその動作を説明する。The operation of the white balance correction circuit configured as described above will be described with reference to FIG.
第２図は基準色温度から色温度が変化した場合のＲ−
Ｙ白バランス補正値15、Ｂ−Ｙ白バランス補正値25を示
した図であり、Ｂの色温度ではＢ−Ｙ色差信号はＥの補
正値、Ｒ−Ｙ色差信号はＨの補正値で白バランス補正が
行われることを示している。加算回路３及び８では、色
温度ＢにおいてはＥ及びＨの補正値で、色温度Ａにおい
てはＦ及びＩの補正値で、色温度ＣにおいてはＧ及びＪ
の補正値で白バランス補正が行われるように、白バラン
ス補正値と色温度で線形性が成立するよう加算定数が設
定されている。この状態で、色温度変化ではない色信号
Ｄが入力される場合、Ｂ−Ｙ白バランス補正は色温度Ｂ
の入力状態と同じ補正を行なおうとし、Ｒ−Ｙ白バラン
ス補正は色温度Ｃの入状態と同じ補正を行なおうとする
為、色温度Ｂと色温度Ｃの間の平衡点で白バランス補正
は安定し、色信号Ｄでは白バランス補正されず、色信号
Ｄの彩度の抑圧が軽減される。FIG. 2 shows R- when the color temperature changes from the reference color temperature.
It is a figure showing a Y white balance correction value 15 and a BY white balance correction value 25. At a color temperature of B, a BY color difference signal is an E correction value, and an RY color difference signal is an H correction value. This indicates that balance correction is performed. In the adder circuits 3 and 8, correction values of E and H at color temperature B, correction values of F and I at color temperature A, and G and J at color temperature C are used.
The addition constant is set so that the white balance correction value and the color temperature have linearity so that the white balance correction is performed with the correction value of. In this state, when the color signal D that is not the color temperature change is input, the BY white balance correction is performed with the color temperature B.
The white balance correction is performed at the equilibrium point between the color temperature B and the color temperature C because the RY white balance correction tries to perform the same correction as the input state of the color temperature C. Is stable, the white balance is not corrected with the color signal D, and the suppression of the saturation of the color signal D is reduced.
以上のようにして、Ｒ−Ｙ白バランス補正値とＢ−Ｙ
白バランス補正値を関連付ける事により、色温度変化時
には白バランス補正が行われ、色入力時には彩度の抑圧
を軽減し、色再現を改善した白バランス補正を行なう事
ができる。As described above, the RY white balance correction value and BY
By associating the white balance correction value, the white balance correction can be performed when the color temperature changes, and the saturation suppression can be reduced at the time of color input, and the white balance correction with improved color reproduction can be performed.
発明の効果 以上のように本発明によれば、Ｒ−Ｙ色差信号の平均
値を求めるＲ−Ｙ平均値検出回路と、前記Ｒ−Ｙ平均値
検出回路出力のＲ−Ｙ平均値と所定値を比較するＲ−Ｙ
平均値比較回路と、Ｂ−Ｙ色差信号の平均値を求めるＢ
−Ｙ平均値検出回路と、前記Ｂ−Ｙ平均値検出回路出力
のＢ−Ｙ平均値と所定値を比較するＢ−Ｙ平均値比較回
路と、前記Ｒ−Ｙ平均値比較回路の出力信号と前記Ｂ−
Ｙ平均値比較回路の出力信号を所定比で加算するＲ−Ｙ
加算回路及びＢ−Ｙ加算回路と、前記Ｒ−Ｙ加算回路の
出力により第１の色信号を利得制御する第１の利得制御
回路と、前記Ｂ−Ｙ加算回路の出力により第２の色信号
を利得制御する第２の利得制御回路と、第３の色信号と
前記第１の利得制御回路の出力信号とからＲ−Ｙ色差信
号を作成するＲ−Ｙ色差回路と、前記第３の色信号と前
記第２の利得制御回路の出力信号とからＢ−Ｙ色差信号
を作成するＢ−Ｙ色差回路を備えた白バランス補正回路
により、色信号の彩度の減少を抑圧し、色再現を改善し
た白バランス補正回路を実現することができる。As described above, according to the present invention, the RY average value detection circuit for obtaining the average value of the RY color difference signals and the RY average value and the predetermined value of the RY average value detection circuit output. RY to compare
An average value comparison circuit and B for obtaining an average value of BY color difference signals
-Y average value detection circuit, BY average value comparison circuit for comparing the BY average value of the BY average value output circuit with a predetermined value, and output signal of the RY average value comparison circuit B-
RY for adding the output signals of the Y average value comparison circuit at a predetermined ratio
An adder circuit and a BY adder circuit; a first gain control circuit for gain-controlling the first color signal by the output of the RY adder circuit; and a second color signal by the output of the BY adder circuit. A second gain control circuit for controlling the gain, an RY color difference circuit for creating an RY color difference signal from a third color signal and an output signal of the first gain control circuit, and the third color A white balance correction circuit having a BY color difference circuit that creates a BY color difference signal from the signal and the output signal of the second gain control circuit suppresses the saturation reduction of the color signal and reproduces the color. It is possible to realize an improved white balance correction circuit.
第１図は本発明の一実施例における白バランス補正回路
のブロック図、第２図は同実施例の白バランス補正特性
図、第３図は従来の白バランス補正回路のブロック図で
ある。 １……Ｒ−Ｙ平均値検出回路、２……Ｒ−Ｙ平均値比較
回路、3,8……加算回路、4,9……利得制御回路、５……
Ｒ−Ｙ色差信号、６……Ｂ−Ｙ平均値検出回路、７……
Ｂ−Ｙ平均値比較回路、10……Ｂ−Ｙ色差回路。FIG. 1 is a block diagram of a white balance correction circuit according to an embodiment of the present invention, FIG. 2 is a white balance correction characteristic diagram of the same embodiment, and FIG. 3 is a block diagram of a conventional white balance correction circuit. 1 ... RY average value detection circuit, 2 ... RY average value comparison circuit, 3,8 ... adding circuit, 4,9 ... gain control circuit, 5 ...
RY color difference signal, 6 ... BY average value detection circuit, 7 ...
BY average value comparison circuit, 10 ... BY color difference circuit.
Claims (1)
均値検出回路と、前記Ｒ−Ｙ平均値検出回路出力のＲ−
Ｙ平均値と所定値を比較するＲ−Ｙ平均値比較回路と、
Ｂ−Ｙ色差信号の平均値を求めるＢ−Ｙ平均値検出回路
と、前記Ｂ−Ｙ平均値検出回路出力のＢ−Ｙ平均値と所
定値を比較するＢ−Ｙ平均値比較回路と、前記Ｒ−Ｙ平
均値比較回路の出力信号と前記Ｂ−Ｙ平均値比較回路の
出力信号を所定比で加算するＲ−Ｙ加算回路及びＢ−Ｙ
加算回路と、前記Ｒ−Ｙ加算回路の出力により、第１の
色信号を利得制御する第１の利得制御回路と、前記Ｂ−
Ｙ加算回路の出力により、第２の色信号を利得制御する
第２の利得制御回路と、第３の色信号と前記第１の利得
制御回路の出力信号とからＲ−Ｙ色差信号を作成するＲ
−Ｙ色差回路と、前記第３の色信号と前記第２の利得制
御回路の出力信号とから、Ｂ−Ｙ色差信号を作成するＢ
−Ｙ色差回路を備えた白バランス補正回路。1. An RY average value detection circuit for obtaining an average value of RY color difference signals, and an R-Y output of the RY average value detection circuit.
An RY average value comparison circuit for comparing the Y average value with a predetermined value,
A BY average value detecting circuit for obtaining an average value of the BY color difference signal; a BY average value comparing circuit for comparing a BY average value of the BY average value output circuit with a predetermined value; An RY adder circuit for adding the output signal of the RY average value comparison circuit and the output signal of the BY average value comparison circuit at a predetermined ratio, and BY.
An adder circuit, a first gain control circuit that controls the gain of the first color signal by the output of the RY adder circuit, and the B-
An RY color difference signal is created from the second gain control circuit that controls the gain of the second color signal by the output of the Y addition circuit, the third color signal, and the output signal of the first gain control circuit. R
-Y color difference circuit, B for generating a BY color difference signal from the third color signal and the output signal of the second gain control circuit B
-White balance correction circuit with Y color difference circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63009838A JPH0824375B2 (en) | 1988-01-20 | 1988-01-20 | White balance correction circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63009838A JPH0824375B2 (en) | 1988-01-20 | 1988-01-20 | White balance correction circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01186092A JPH01186092A (en) | 1989-07-25 |
| JPH0824375B2 true JPH0824375B2 (en) | 1996-03-06 |
Family
ID=11731270
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63009838A Expired - Fee Related JPH0824375B2 (en) | 1988-01-20 | 1988-01-20 | White balance correction circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0824375B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69315285T2 (en) * | 1992-09-02 | 1998-05-28 | Matsushita Electric Ind Co Ltd | Device for processing an image signal |
-
1988
- 1988-01-20 JP JP63009838A patent/JPH0824375B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01186092A (en) | 1989-07-25 |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |