JPH02142292A - Chrominance signal processor - Google Patents
Chrominance signal processorInfo
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- JPH02142292A JPH02142292A JP63296731A JP29673188A JPH02142292A JP H02142292 A JPH02142292 A JP H02142292A JP 63296731 A JP63296731 A JP 63296731A JP 29673188 A JP29673188 A JP 29673188A JP H02142292 A JPH02142292 A JP H02142292A
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Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は補色フィルターを装着したカラービデオカメラ
やカラースチルビデオカメラ等のカラー信号処理装置に
関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color signal processing device such as a color video camera or a color still video camera equipped with a complementary color filter.
従来この種の装置においては、例えば第７図（ａ）に示
すような色フィルターを装着し、第３図に示すような信
号処理をすることで、最終的に輝度と２つの色差信号Ｒ
−Ｙ、Ｂ−Ｙを得るのが普通である。Conventionally, in this type of device, by installing a color filter as shown in FIG. 7(a) and performing signal processing as shown in FIG. 3, the luminance and two color difference signals R are finally obtained.
-Y, BY are usually obtained.
このような従来の方式の色信号処理においてはまず、水
平方向に隣り合っていて、かつ異なる色フィルターを装
着されている画素からの出力を減算した結果である。In such conventional color signal processing, the result is first subtracted from outputs from pixels adjacent in the horizontal direction and equipped with different color filters.
色差信号からの演算処理が行われる。例えば第７図（ａ
）に示す色フィルター配列をインタレース走査すれば各
フィールドの奇数列目からは減算器３０４を介してＣｒ
＝ （Ｍｇ−Ｇｒ）という減算結果が得られ、偶数列
目はＣ２＝ （Ｙｅ−Ｃｙ）という減算結果が得られる
。Arithmetic processing is performed from the color difference signals. For example, Fig. 7 (a
) If the color filter array shown in ) is interlaced scanned, Cr
A subtraction result of = (Mg-Gr) is obtained, and a subtraction result of C2= (Ye-Cy) is obtained for the even-numbered column.
これに対して３０５の色信号処理部では適当な方法でホ
ワイトバランス、γ変換などの色処理演算が行われる。On the other hand, a color signal processing unit 305 performs color processing calculations such as white balance and γ conversion using an appropriate method.
次に、これらの線順次化されている色差信号Ｃ１／Ｃ２
に対し、ｌＨ遅延線などを含む同時化回路３０６を用い
て同時化し、更にこれらを色差マトリクス回路３０７に
通すことにより、色差軸を適当に回転し、最終的に２つ
の色差信号Ｒ−Ｙ、 Ｂ−Ｙを得ている。Next, these line-sequential color difference signals C1/C2
The signals are synchronized using a synchronization circuit 306 including an IH delay line, etc., and then passed through a color difference matrix circuit 307 to appropriately rotate the color difference axis and finally produce two color difference signals R-Y, I'm getting B-Y.
〔発明が解決しようとしている問題点〕しかし、このよ
うな方式の色処理方法には、次のような２つの根本的な
問題がある。[Problems to be Solved by the Invention] However, this type of color processing method has the following two fundamental problems.
［Ａ］ホワイトバランスがとりにくい。[A] White balance is difficult to obtain.
三管式カメラやＲＧＢ純色タイプのカメラではＧに対す
るＲとＢの比を色温度に応じて変化させることでホワイ
トバランスがとれるのに対し、この種の装置では色情報
が色差の形で出てくるので、例えば色温度に応じて、輝
度信号の何割かを色差信号に加減算することによって、
白色に対する色差信号を強制的にゼロにし、ホワイトバ
ランスをとっている。この方法は原理的にも正しく巾広
い色温度範囲で精度良くホワイトバランスをとることは
極めて極めて難しい。With three-tube cameras and RGB pure color type cameras, white balance can be achieved by changing the ratio of R and B to G according to the color temperature, but with this type of device, color information is output in the form of color differences. For example, by adding or subtracting a percentage of the luminance signal to the color difference signal depending on the color temperature,
White balance is achieved by forcibly setting the color difference signal for white to zero. This method is correct in principle, and it is extremely difficult to achieve accurate white balance over a wide color temperature range.
［Ｂ］色差のままγをかけるので、色の再現性が良くな
い。[B] Since the color difference is multiplied by γ, the color reproducibility is not good.
王管式カメラやＲＧＢ純色タイプのカメラではＮＴＳＣ
方式に従って色分離された出力ＲＧＢにγをけてＲ１・
０丁・Ｂγを得たのち、２つの色差Ｒγ−Ｙ、Ｂ’−Ｙ
を得る。但しＹはＹ＝０．３０Ｒγ十０．５９Ｇγ十０
．１１Ｂγである。NTSC for royal tube type cameras and RGB pure color type cameras.
The output RGB color separated according to the method is multiplied by γ and R1・
After obtaining 0 pieces Bγ, two color differences Rγ-Y, B'-Y
get. However, Y is Y=0.30Rγ+0.59Gγ+0
．． 11Bγ.
ところが補色タイプのカメラでは色信号は最初に差をと
られてからγをかけられるので、（Ｍｇ−Ｇｒ）γのよ
うに差の形のままでγをかけられてしまう。従って後で
どう補正しても正規のＮＴＳＣと対応のついた色信号が
得られず色の再現性はよ（ない。However, in a complementary color type camera, the color signal is first subtracted and then multiplied by γ, so that it is multiplied by γ in the form of a difference, such as (Mg-Gr) γ. Therefore, no matter how you correct it later, you will not be able to obtain a color signal that corresponds to the regular NTSC, and the color reproducibility will be poor.
上記の問題点を解決するため、出願人は先に第８図に示
すように、得られるすべての色情報を２次元の補間フィ
ルターによって同時化した後、これらの間のマトリクス
演算によってＲ，Ｇ、Ｈの３つの色信号を形成し、この
状態でホワイトバランス、γ変換を行う方法を提案して
いる。In order to solve the above problem, the applicant first synchronized all the obtained color information using a two-dimensional interpolation filter, and then performed R, G, and G colors by matrix calculation between them, as shown in FIG. , H, and perform white balance and γ conversion in this state.
即ち第８図中、２０１はマトリクス状の補色フィルター
が配されたイメージセンサ−１２０２はセンサーの出力
をＡ／Ｄ変換するＡ／Ｄ変換器であり、このＡ／Ｄ変換
器出力の各色信号は２次元の補間フィルター２０６〜２
０９により同時化された後、ＲＧＢ変換器でマドリスク
変換されて、Ｒ，Ｇ、Ｈの３原色信号となり、その後で
ホワイトバランス、γ変換を行ってから低域輝度信号Ｙ
２、色差信号Ｒ−Ｙ。That is, in FIG. 8, 201 is an image sensor in which a matrix-like complementary color filter is arranged. 1202 is an A/D converter that converts the output of the sensor into A/D, and each color signal of the output of this A/D converter is Two-dimensional interpolation filter 206-2
After being synchronized by 09, it is subjected to Madrisk conversion by an RGB converter to become three primary color signals of R, G, and H. After that, white balance and γ conversion are performed, and then a low-range luminance signal Y
2. Color difference signal R-Y.
Ｂ−Ｙを色差マトリクス回路で形成し、Ｒ−Ｙ。B-Y is formed by a color difference matrix circuit, and R-Y.
Ｂ−ＹはＤ／Ａ変換器２１４．２１５でアナログの色差
信号に変換される。B-Y is converted into an analog color difference signal by D/A converters 214 and 215.
一方、Ａ／Ｄ変換器２０２の出力はＨＰＦ２１６を介し
た後、低域輝度信号ＹＬと加算器２１７で加算されてか
らＤ／Ａ変換器２１８でアナログの輝度信号に変換され
る。On the other hand, the output of the A/D converter 202 passes through the HPF 216, is added to the low-band luminance signal YL in an adder 217, and is then converted into an analog luminance signal by a D/A converter 218.
しかし、その後の研究の結果、この方法によって色再現
性は大巾に向上するがそのかわり、垂直方向のエツジ部
に偽色が発生する現象があられれることがわかった。However, as a result of subsequent research, it was found that although this method greatly improved color reproducibility, it also caused the phenomenon of false colors occurring at vertical edges.
本発明は、先の提案の良好な色再現性を維持したままか
つ、上記の問題点を極めて簡単な構成で有効に解決する
手段を提供することを目的とするものである。An object of the present invention is to provide means for effectively solving the above problems with an extremely simple configuration while maintaining the good color reproducibility of the previous proposal.
本願の第１の発明は、第１の水平走査期間に２つの異な
る色信号がくり返し読み出され、第２の水平走査期間に
上記の２つの色信号とは更に異なる２つの色信号がくり
返し読み出される撮像手段と、第１及び第２の水平走査
期間内の同一走査線上の２つの色信号の無彩色に対する
応答を等しくなるように調整する調整手段と、上記調整
手段による調整後の信号を３行４列のマトリクスの内各
行の右２列の係数の和が互いに等しくまた該マトリクス
の各行の左２列の係数の和が互いに等しいマトリクス演
算手段によってＲＧＢ信号へ変換することを特徴とする
。In the first invention of the present application, two different color signals are repeatedly read out during the first horizontal scanning period, and two color signals different from the above two color signals are repeatedly read out during the second horizontal scanning period. an adjusting means for adjusting the response of two color signals on the same scanning line in the first and second horizontal scanning periods to an achromatic color to be equal; The present invention is characterized in that the sum of the coefficients in the right two columns of each row of the matrix of four rows and four columns is equal to each other, and the sum of the coefficients of the left two columns of each row of the matrix is equal to each other.
本願の第２の発明は第１の水平走査期間に、２つの異な
る第１．第２の色信号がくり返し読み出され、第２の水
平走査期間に上記の２つの色信号とは更に異なる２つの
第３．第４の色信号がくり返し読み出される撮像手段と
、第１及び第２の水平走査期間内の同一走査線上の２つ
の色信号の無彩色に対する応答を等しくなるように調整
する調整手段を持ち、上記調整手段による調整後の色信
号のうち、第１゜第２の色信号の和をとる第１の加算手
段と、第３゜第４の色信号の和をとる第２の加算手段と
、第１゜第２の色信号の差をとる第１の減算手段と、第
３゜第４の色雪号の差をとる第２の減算手段と、第１゜
第２の加算手段の出力の夫々定数倍を加算する第３の加
算手段と、第３の加算手段の出力と、第１゜第２の減算
手段の出力の夫々の定数倍を加算することによってＲＧ
Ｂの信号を形成する演算手段と、を有することを特徴と
する。In the second invention of the present application, two different first . The second color signal is read out repeatedly, and during the second horizontal scanning period, two third color signals, which are different from the above two color signals, are read out repeatedly. an imaging means from which the fourth color signal is repeatedly read out; and an adjustment means for adjusting the responses of the two color signals on the same scanning line in the first and second horizontal scanning periods to an achromatic color so that they are equal; Of the color signals adjusted by the adjusting means, a first adding means takes the sum of the first and second color signals, a second adding means takes the sum of the third and fourth color signals, and a second adding means takes the sum of the third and fourth color signals. 1゜first subtraction means for taking the difference between the second color signals, 3゜second subtraction means for taking the difference between the fourth color signals, and outputs of the 1゜second addition means, respectively. RG is obtained by adding a third addition means for adding a constant multiple, the output of the third addition means, and a constant multiple of the output of the first and second subtraction means.
A calculation means for forming a signal of B.
このように構成することによりＲ，Ｇ、Ｂ信号を夫々形
成する為の演算手段の構成として、一般に１２回の乗算
と９回の加減算が必要であった（４Ｘ３）のマトリクス
演算を、わずか８回の乗算と１１回の加減算で非常に効
率よ（行い、かつ大きな問題点であった垂直偽色の発生
を極小化できる。With this configuration, the (4×3) matrix operation, which generally requires 12 multiplications and 9 additions/subtractions, can be reduced to just 8 as the configuration of the calculation means for forming R, G, and B signals, respectively. With 1 multiplications and 11 additions/subtractions, it is very efficient and can minimize the occurrence of vertical false color, which was a major problem.
本発明の詳細な説明する前にまず、垂直エツジにおける
偽色発生の原因を考え、次にこれを防止する条件を考え
る。Before explaining the present invention in detail, we will first consider the cause of the occurrence of false colors at vertical edges, and then consider the conditions for preventing this.
第８図示の構成において、
例えば第６図（ａ）に示す色フィルター配列を使う場合
には、次にような（３Ｘ４）の−次マトリクス（ａ ＋
１ ）の演算によってＲＧＢへ変換する。In the configuration shown in FIG. 8, for example, when using the color filter array shown in FIG. 6(a), the following (3×4) -order matrix (a +
1) Conversion to RGB is performed.
（１）式右辺のＭｇ、Ｇｒ、Ｃｙ、Ｙｅは第８図に示す
２次元補間フィルター２０６〜２０９で同時化されてい
る。Mg, Gr, Cy, and Ye on the right side of equation (1) are synchronized by two-dimensional interpolation filters 206 to 209 shown in FIG.
今、第７図のように垂直方向に周期が１丁度４画素分の
白黒の濃淡パターンが被写体の場合を考える。Now, let us consider the case where the subject is a black and white shading pattern with a period of exactly 4 pixels in the vertical direction as shown in FIG.
ここで色温度で決まるパラメータαβを無彩色に対して を満たすように、予め決めたとする。Here, the parameter αβ determined by the color temperature is Suppose that we have decided in advance to satisfy the following.
この時、Ｍｇ、Ｇｒの位置はぴったり暗部に一致し、又
Ｃｙ、Ｙｅの位置はぴったり明部と一致しているのでど
のような補間フィルターを用いても、となる、但し、ｖ
ｌ、ｖ２は明るさに対する画素信号出力で第８図の場合
Ｖ、＜Ｖ２である。At this time, the positions of Mg and Gr exactly match the dark areas, and the positions of Cy and Ye exactly match the bright areas, so no matter what interpolation filter is used,
1 and v2 are pixel signal outputs with respect to brightness, and in the case of FIG. 8, V, <V2.
従って（１） （２） （３）より、
Ｒ＝（ａｔｔ ＋ａ１２ ／ （１）Ｖ＋ ＋（ａｈａ
＋ａ１４／β）Ｖ２Ｇ ＝ （ａ、、 ＋ａ２２ ／
ａ ）Ｖ１＋（ａ２３ ＋ａ２４／β） Ｖ ２Ｂ
＝ （ａ３． ＋ａ３２ ／ ａ ）Ｖｌ ＋（ａ、
＋ａｕ／β） Ｖ ２となる。Therefore, from (1) (2) (3), R=(att +a12 / (1)V+ +(aha
+a14/β)V2G = (a,, +a22/
a) V1+(a23 +a24/β) V 2B
= (a3. +a32 / a) Vl + (a,
+au/β) V 2.
この被写体の濃淡パターンはもともと白黒の被写体であ
るからすべてのｖ３．ｖ２について偽色が出ないために
は、
また５ａｌｌ−ａ１２＝２Ｒ１Ｒ１３”＋４ ＝２Ｒ２
の２条件が同時に成立しなければいけない。The shading pattern of this subject is originally a black and white subject, so all v3. In order to avoid false color for v2, 5all-a12=2R1R13”+4 =2R2
These two conditions must be satisfied simultaneously.
今、Ｇｒの出力をα倍、ｃｙの出力を８倍したものを各
々（Ｇｒ） ’ 、 （Ｙｅ） ’ とすると（１）
のかわりにによって変換すると考える。この時（５）及
び（６）の条件は
ａ＋１十ａ１２＝ａ２１＋ａ２２＝ａ３＋＋ａａｚ
（８）ａ １３ ＋ａ 、４
＝ ８２３ ＋ａ、、ａ°ａ３３＋ａ３４
（９）と書き換えられる。Now, if the output of Gr multiplied by α and the output of cy multiplied by 8 are respectively (Gr)' and (Ye)', then (1)
Consider converting by instead. At this time, the conditions for (5) and (6) are a+10a12=a21+a22=a3++aaz
(8) a 13 +a , 4
= 823 +a,,a°a33+a34
It can be rewritten as (9).
ここで（８） （９）の共通部分を各々２Ｐ、２Ｑとお
（。Here, the common parts of (8) and (9) are respectively 2P and 2Q (.
ａｎ ＋ａ１２＝ ａ２＋ ＋ａ２２＝ ａｓ１＋Ｂ５
２＝ ２Ｐ （８）’ａ １３ ＋ａ
＋４ ＝ Ｒ２３＋ａ２４ ＝ ａＨ＋ａ３４ ＝ ２
Ｑ （９）’ａｌｌ −８２２＝２Ｇ
１８２３−Ｒ２４＝２Ｇ ２ａ３１−ａｔ２ ＝２８
！ａ３３−８３４ ＝２８２・・・・（１０）
とすると、例えばＲは（７）より
Ｒ＝ ａ、、 Ｍｇ＋ａ、□Ｇ？ ＋ａ、３Ｃｙ十ａ、
、 Ｙｅ’なので（８’ ） （９’ ） （１０）に
よりＲ＝ （Ｐ＋Ｒ＋）Ｍｇ＋（Ｐ−Ｒ＋）Ｇｒ’
＋（Ｑ＋Ｒ２）Ｃｙ＋（Ｑ−Ｒ２）Ｙｅ’＝Ｐ（Ｍｇ＋
Ｇｒ’ ）＋Ｑ（Ｃｙ＋Ｙｅ’ ）十Ｒ＋（Ｍｇ−Ｇｒ
′）＋Ｒｚ（Ｃｙ−Ｙｅ′）・・・・（１１）
となる。また、同様に
Ｇ ＝Ｐ（Ｍｇ＋Ｇｒ’ ）＋Ｑ（Ｃｙ十Ｙｅ’ ）＋
Ｇ＋（Ｍｇ−Ｇｒ′）＋Ｇ２（Ｃｙ−Ｙｅ’ ）・・・
・（１２）
Ｂ ＝Ｐ（Ｍｇ＋Ｇｒ′）＋Ｑ（Ｃｙ＋Ｙｅ′）＋Ｂ＋
（Ｍｇ−Ｇｒ’ ）十Ｂｚ（Ｃｙ Ｙｅ’ ）・・・
・（１３）
となる。an +a12= a2+ +a22= as1+B5
2= 2P (8)'a 13 +a
+4 = R23+a24 = aH+a34 = 2
Q (9)'all -822=2G
1823-R24=2G 2a31-at2=28
! a33-834 =282...(10) For example, from (7), R = a, Mg+a, □G? +a, 3Cy tena,
, Ye', so (8') (9') (10), R= (P+R+)Mg+(P-R+)Gr'
+(Q+R2)Cy+(Q-R2)Ye'=P(Mg+
Gr')+Q(Cy+Ye')1R+(Mg-Gr
')+Rz(Cy-Ye') (11). Similarly, G = P (Mg + Gr') + Q (Cy + Ye') +
G+(Mg-Gr')+G2(Cy-Ye')...
・(12) B = P (Mg + Gr') + Q (Cy + Ye') + B +
(Mg-Gr') 10 Bz (Cy Ye')...
・(13) becomes.
一般に（７）のように３×４のマトリクス演算を行うと
、３ｘ４＝１２回の乗算と３Ｘ３＝９回の加減算が必要
である。Generally, when performing a 3×4 matrix operation as in (7), 3×4=12 multiplications and 3×3=9 additions/subtractions are required.
しかし、本発明では（５） （６）の条件を利用するこ
とによって、ＲＧＢを（１１） （１２） （１３）の
ように演算する。However, in the present invention, by using the conditions (5) and (6), RGB is calculated as (11) (12) (13).
この結果、次のように乗算回数の少い演算で実行できる
。例えばＲについては
■ Ｐ （Ｍｇ−Ｇｒ’ ） 十Ｑ （Ｃｙ十Ｙｅ’
）の演算３回の加減算と２回の乗算
■ Ｒ、（Ｍｇ−Ｇｒ’ ）の演算
１回の加減算と１回の乗算
■ Ｒ２（Ｃｙ Ｙｅ’）の演算
１回の加減算と１回の乗算
■ ■十■＋■の演算
２回の加減算
が必要である。このうち■と■、■の加減算は各色間で
共通化できるので、
全部で ３＋１＋１＋３Ｘ２＝１１回の加減算と、２＋
ａＸｌ＋３Ｘ１＝８回の乗算で
実行できる。As a result, the following calculation can be performed with a small number of multiplications. For example, for R, ■ P (Mg-Gr') 10Q (Cy0Ye'
) operations: 3 additions/subtractions and 2 multiplications ■ R, (Mg-Gr') operations: 1 addition/subtraction and 1 multiplication ■ R2 (Cy Ye') operations: 1 addition/subtraction and 1 multiplication ■ Two additions and subtractions are required for the calculation of (10) + (2). Among these, the addition and subtraction of ■, ■, and ■ can be shared between each color, so 3+1+1+3X2=11 additions and subtractions, and 2+
This can be executed by multiplying aXl+3X1=8 times.
（５） （６）式の条件は非常に強い条件であり、本発
明はこの特徴を利用することによって、一般に１２回の
乗算と９回の加減算の必要な（４ｘ３）のマトリクス演
算を、上述したようにわずか８回の乗算と１１回の加減
算で非常に効率よく行い、かつ大きな問題点であった垂
直偽色の発生を極小化できる。(5) The condition in equation (6) is a very strong condition, and by utilizing this feature, the present invention can solve the above-mentioned (4x3) matrix operation, which generally requires 12 multiplications and 9 additions/subtractions. As described above, the process is very efficient with only 8 multiplications and 11 additions/subtractions, and the occurrence of vertical false color, which was a major problem, can be minimized.
第２図は本発明を第７図のようにＣＣＤをインタレース
走査する場合の実施例を示す。FIG. 2 shows an embodiment of the present invention in which a CCD is interlaced scanned as shown in FIG.
本発明を実施するためにはＭｇ、 Ｇｒ、 Ｃｙ、 Ｙ
ｅの４つの色信号が同時化されていなければならない。In order to carry out the present invention, Mg, Gr, Cy, Y
The four color signals of e must be synchronized.
なぜならこれら４つの情報を演算によってＲＧＢへ変換
するからである。This is because these four pieces of information are converted into RGB by calculation.
例えば、第７図のようなセンサー出力の場合、Ｍｇに注
目すると、そのサンプリングの位置は第６図（ｂ）に○
印で示した所になる。その他のＸ印の所は他の色情報は
あるがＭｇの色情報がないので○印のついたデータ（Ａ
−Ｈなど）の適当な重みっけで補間する。これが２次元
補間フィルターによる同時化である。これは各色に対し
て行われる。For example, in the case of the sensor output as shown in Figure 7, if we focus on Mg, the sampling position is shown in Figure 6(b).
It will be at the place indicated by the mark. Other X-marked areas have other color information, but there is no Mg color information, so the data marked with an ○ (A
-H, etc.) with an appropriate weight. This is synchronization using a two-dimensional interpolation filter. This is done for each color.
以上を念頭において、以下第２図を使用して説明する。With the above in mind, explanation will be given below using FIG. 2.
ＣＤＤセンサー２０１には第７図に示すような、４種の
カラーフィルターが夫々の画素に対応して配置されてい
る。センサー２０１からインタレース走査で一画素ごと
に読み出された画素信号はＡＧＣ回路２３０でゲインを
調整されたのちＡ／Ｄ変換器２０２で、読み出しクロッ
クに同期したタイミングでＡ／Ｄ変換される。後で行う
色処理のために、このＡ／Ｄ変換器はリニヤな特性が良
く、量子化誤差の点から考えて、８ｂｉｔ以上で行うの
が望ましい。In the CDD sensor 201, four types of color filters are arranged corresponding to each pixel, as shown in FIG. A pixel signal read out pixel by pixel from the sensor 201 by interlaced scanning has its gain adjusted by an AGC circuit 230, and is then A/D converted by an A/D converter 202 at a timing synchronized with a read clock. For color processing to be performed later, this A/D converter has good linear characteristics, and from the viewpoint of quantization error, it is desirable to use 8 bits or more.
輝度信号はバイパスフィルター２１６で高域成分が検出
され後述するような方法で得られる輝度の低域成分ｙｔ
、と加算器２１７で加算され、Ｄ／Ａ変換器２１８でＤ
／Ａ変換され出力される。The high-frequency component of the luminance signal is detected by the bypass filter 216, and the low-frequency component yt of the luminance is obtained by a method described later.
, are added by the adder 217, and D is added by the D/A converter 218.
/A conversion and output.
次に、定数Ｐ＋ Ｑ、ＲＩＴ Ｒ２１Ｇ ｌ＋ Ｇ２＋
Ｂ ＩＴ Ｂ２の決め方について説明する。一般に（
７）式のマトリクスではパラメータの数は１２であるが
、条件（５） （６）式によってパラメータの数が８個
に集約されている。Next, constant P+ Q, RIT R21G l+ G2+
How to determine B IT B2 will be explained. in general(
Although the number of parameters is 12 in the matrix of formula 7), the number of parameters is aggregated to eight due to conditions (5) and formula (6).
Ｍｇ、Ｇｒ、Ｃｙ、Ｙｅのカラーフィルターの分光特性
Ｍｇ（λ）、Ｇｒ（λ）、Ｃｙ（λ）、Ｙｅ（λ）を３
８０ｎｍから７８０ｎｍまでｌｏｎｍ間隔で測定しＭｇ
（λｉ）、Ｇｒ（λｉ）、Ｃｙ（λｉ）、Ｙｅ（λｉ）
（ｉ＝１．＝−，４１）を得る。Spectral characteristics Mg (λ), Gr (λ), Cy (λ), Ye (λ) of Mg, Gr, Cy, Ye color filters are 3
Mg measured at lonm intervals from 80nm to 780nm
(λi), Gr (λi), Cy (λi), Ye (λi)
(i=1.=-,41) is obtained.
次にＮＴＳＣのＲＧＢの理想分光特性ｒ（λ、）。Next is the ideal spectral characteristic r(λ,) of NTSC RGB.
ｇ（λ＋）、ｂ（λＩ）を、例えば“色彩科学ハンドブ
ック東京大学出版会（１９８１）“より読みとる。g(λ+) and b(λI) are read from, for example, "Color Science Handbook, University of Tokyo Press (1981)".
そして（１１）、（１２）、（１３）を書き直すと、と
なる。Then, rewriting (11), (12), and (13) yields.
従って、（１４）によって交換されたＲ、 Ｇ、 Ｂの
等測的分光特性Ｒ（λ）、Ｇ（λ）、Ｂ（λ）はとなる
。これを先に述べたＮＴＳＣのＲＧＢの理想分光特性ｒ
（、λ）ｇ（λ）ｂ（λ）にできるだけ近似させる。Therefore, the isometric spectral characteristics R(λ), G(λ), B(λ) of R, G, B exchanged by (14) are as follows. This is the ideal spectral characteristic r of RGB of NTSC mentioned earlier.
(,λ)g(λ)b(λ) as much as possible.
但し、８コのパラメータｐ、 Ｑｌ及びＲ１，ＧＩ、
Ｂ＋（ｉ＝１．２）は色温度によらず一定にしたいので
例えば５１００°Ｋに対するα、βを用いて、これらの
パラメータを決めるとよい。However, the eight parameters p, Ql and R1, GI,
Since B+ (i=1.2) is desired to be constant regardless of the color temperature, these parameters may be determined using, for example, α and β for 5100°K.
このためには、例えば最小２乗法を用いる。For this purpose, for example, the least squares method is used.
即ち、誤差関数Ｅ （Ｐ＋ ＱＩ Ｂ＋、 に＋、 ｌ
３１）を、次のように定義する。That is, the error function E (P+ QI B+, +, l
31) is defined as follows.
Ｅ（Ｐ Ｑ Ｂ＋ ＧＩ Ｂθ ＝ Σ （
［ｒ（λ＋）−Ｒ（λθコ２＋［ｇ（λ１）−Ｇ（λＩ
）］２
＋［ｂ（λ＋）−Ｂ（λｉ）］”１
これをＰ＋ Ｑ、 Ｂ＋、 ＧＩ、 Ｉｈ （ｉ＝１
．２）で各々編微分してＯと置（ことにより、８元連立
１次方程式が得られるので、これをＰ＋ Ｑｒ Ｒｉ＋
ＧＩ、 Ｂｌについて解けばよい。E(P Q B+ GI Bθ = Σ (
[r(λ+)-R(λθko2+[g(λ1)-G(λI
)]2 + [b(λ+)-B(λi)]”1 This is P+ Q, B+, GI, Ih (i=1
．． 2), respectively, and set it as O (by this, an eight-element simultaneous linear equation is obtained, so this can be written as P+ Qr Ri+
Just solve for GI and Bl.
このように色について最適化すると必ずしもＰ＝Ｑにな
らないがＰ＝Ｑの場合よりパラメータが１つ多い分だけ
色再現が良好である。Optimizing colors in this way does not necessarily result in P=Q, but the color reproduction is better because there is one more parameter than in the case of P=Q.
尚、このように構成することでα、βを調整することが
でき、ホワイトバランスがとれる。何故なら減算器１０
５，１０６の出力が０になると、必ずＲ＝Ｇ＝Ｂとなる
からである。Note that with this configuration, α and β can be adjusted, and white balance can be achieved. Because subtractor 10
This is because when the output of 5,106 becomes 0, R=G=B.
次に、γ変換器の１２では、テーブル変換によてＲＧＢ
信号がγ変換される。Next, in the γ converter 12, RGB is converted by table conversion.
The signal is gamma transformed.
色差マトリクス部２１３では（１６）式に従ってマトリ
クス演算が行われる。ここでも整数型の固定乗算を行う
ため、各係数といくつかの２のべき乗の加減算と近似す
ると良い。The color difference matrix unit 213 performs matrix calculation according to equation (16). Since fixed multiplication of integer type is performed here as well, it is best to approximate it by adding and subtracting each coefficient and several powers of 2.
・・・・（１６）
第２の実施例として、
前述のＰとＱが等しい場合が考えられる。Ｐ＝Ｑでかつ
Ｍｇ（λ）＋Ｇｒ （Ｘ） 〜Ｃｙ （λ） ＋Ｙｅ
（λ）と考えられるような場合、加算器１０３． １０
４、定数倍器１０４，１０５が共通化できる。(16) As a second example, a case can be considered in which the above-mentioned P and Q are equal. P=Q and Mg(λ)+Gr(X) ~Cy(λ)+Ye
(λ), the adder 103. 10
4. Constant multipliers 104 and 105 can be shared.
もちろん上述のようなハードワイヤードな構成をとらず
にＤＳＰ （デジタル・シグナル・プロセシング）など
を用いてソフトウェアで直接（５）、 （６）式の条
件を満たす係数［ａ ＋ｒ ］を用いてマトリクス演算
を行ってＲＧＢへ交換してもよい。Of course, without using the hard-wired configuration described above, it is possible to directly perform matrix calculations using the coefficients [a + r] that satisfy the conditions of equations (5) and (6) using software such as DSP (digital signal processing). You may also do this to exchange it to RGB.
又、本発明は第６（ａ）図のようなフィルターを有する
センサーをインタレース走査する場合以外にも、第１０
図のようなフィルター配置のセンサー出力を２水平ライ
ンずつ垂直方向に混合して読み出す場合や、一画素を２
分割してフィルターを貼り合せたＣＯＤの場合のように
信号が水平方向に２色垂直方向に２色計４色の繰り返し
であるのであっても有効である。Furthermore, the present invention is applicable not only to interlaced scanning of a sensor having a filter as shown in FIG.
When reading out sensor outputs with a filter arrangement as shown in the figure, by mixing them vertically in two horizontal lines, or when reading one pixel by two
It is also effective even if the signal is a repetition of two colors in the horizontal direction and two colors in the vertical direction, a total of four colors, as in the case of COD in which filters are divided and pasted together.
また、輝度信号はＲ，Ｇ、Ｈの重み付けで作られるＹＬ
とセンサー信号はＨＰＦして得られる信号との和を用い
て色再現性の向上を図ったが、ＬＰＦＬないＭｇ、Ｇｒ
、Ｃｙ、Ｙｅ倍信号本発明と同じ重み付けをしてそのま
ま用いてもよい。In addition, the luminance signal is YL, which is created by weighting R, G, and H.
We attempted to improve color reproducibility by using the sum of the sensor signal and the signal obtained by HPPF, but Mg, Gr without LPFL
, Cy, Ye multiplied signals may be used as they are with the same weighting as in the present invention.
また、無彩色に対して応答を等しくする手段としてＡ／
Ｄ変換器の前を４チヤンネルにしてアナログ回路で実行
してもよいことはいうまでもない。Also, as a means to equalize the response to achromatic colors, A/
It goes without saying that the analog circuit may be used with four channels in front of the D converter.
以上のように、本発明においては色再現性に優れており
、かつ垂直偽色の発生も少ない。しかもカラー信号処理
装置を極めて簡単なハードウェア構成で実現できる。As described above, the present invention has excellent color reproducibility and less occurrence of vertical false colors. Moreover, the color signal processing device can be realized with an extremely simple hardware configuration.
第１図は本発明の実施例を示す図、第２図は本発明によ
るビデオカメラの信号処理装置のブロック図、第３図は
、従来例によるビデオカメラの信号処理装置のブロック
図、第４図、第５図は補間フィルターの構成例を示す図
、第６図（ａ）、 （ｂ）は、色フィルターの配列例
を示す図、第７図は垂直偽色の発生を説明する図、第８
図は先願によるビデオカメラの信号処理装置のブロック
図、第９図は色フィルターの他の配列例を示す図である
。FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a block diagram of a video camera signal processing device according to the present invention, FIG. 3 is a block diagram of a conventional video camera signal processing device, and FIG. 5 is a diagram showing an example of the configuration of an interpolation filter, FIGS. 6(a) and 6(b) are diagrams showing an example of the arrangement of color filters, and FIG. 7 is a diagram illustrating the occurrence of vertical false color. 8th
The figure is a block diagram of a signal processing device for a video camera according to the prior application, and FIG. 9 is a diagram showing another example of arrangement of color filters.
Claims (2)
くり返し読み出され、第２の水平走査期間に上記の２つ
の色信号とは更に異なる２つの色信号がくり返し読み出
される撮像手段と、第１及び第２の水平走査期間内の同
一走査線上の２つの色信号の無彩色に対する応答を等し
くなるように、調整する調整手段と、上記調整手段によ
る調整後の信号を３行４列のマトリクスの内各行の右２
列の係数の和が互いに等しく、また該マトリクスの各行
の左２列の係数の和が互いに等しい、マトリクス演算手
段によってＲＧＢ信号へ変換することを特徴とするカラ
ー信号処理装置。(1) During the first horizontal scanning period, two different color signals are
an imaging means that is repeatedly read out and in which two color signals further different from the above two color signals are repeatedly read out during a second horizontal scanning period; an adjusting means for adjusting the responses of the two color signals to the achromatic color to be equal;
A color signal processing device characterized in that the sum of coefficients in columns is equal to each other, and the sum of coefficients in two left columns of each row of the matrix is equal to each other, and conversion into RGB signals is performed by a matrix calculation means.
色信号が、くり返し読み出され、第２の水平走査期間に
上記の２つの色信号とは更に異なる２つの第３、第４の
色信号がくり返し読み出される撮像手段と、第１及び第
２の水平走査期間内の同一走査線上の２つの色信号の無
彩色に対する応答を等しくなるように調整する調整手段
を持ち、上記調整手段による調整後の色信号のうち、第
１、第２の色信号の和をとる第１の加算手段と第３、第
４の色信号の和をとる第２の加算手段と、第１、第２の
色の信号の差をとる第１の減算手段と、第３、第４の色
信号の差をとる第２の減算手段と、第１、第２の加算手
段の出力の夫々定数倍を加算する第３の加算手段と、第
３の加算手段の出力と、第１、第２の減算手段の出力の
夫々の定数倍を加算することによってＲＢＧの信号を形
成する演算手段と、を有することを特徴とするカラー信
号処理装置。(2) During the first horizontal scanning period, two different first and second color signals are repeatedly read out, and during the second horizontal scanning period, two third color signals, which are different from the above two color signals, are read out repeatedly. an imaging means from which the fourth color signal is repeatedly read out; and an adjustment means for adjusting the responses of the two color signals on the same scanning line in the first and second horizontal scanning periods to an achromatic color so that they are equal; A first addition means that takes the sum of the first and second color signals among the color signals adjusted by the adjustment means; a second addition means that takes the sum of the third and fourth color signals; , a first subtraction means for taking the difference between the second color signal, a second subtraction means for taking the difference between the third and fourth color signals, and constants for the outputs of the first and second addition means, respectively. a third addition means for adding times, and an arithmetic means for forming an RBG signal by adding constant times the output of the third addition means and the outputs of the first and second subtraction means, respectively; A color signal processing device comprising:
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63296731A JP2744260B2 (en) | 1988-11-22 | 1988-11-22 | Color signal processing device |
| EP89311508A EP0368614B1 (en) | 1988-11-09 | 1989-11-07 | Color signal processing apparatus |
| DE89311508T DE68909171T2 (en) | 1988-11-09 | 1989-11-07 | Color signal processing device. |
| US07/913,978 US5202756A (en) | 1988-11-09 | 1992-07-16 | Color signal processing apparatus using plural luminance signals |
| US08/542,428 US5581298A (en) | 1988-11-09 | 1995-10-12 | Color signal processing apparatus using plural luminance signals |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63296731A JP2744260B2 (en) | 1988-11-22 | 1988-11-22 | Color signal processing device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02142292A true JPH02142292A (en) | 1990-05-31 |
| JP2744260B2 JP2744260B2 (en) | 1998-04-28 |
Family
ID=17837364
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63296731A Expired - Lifetime JP2744260B2 (en) | 1988-11-09 | 1988-11-22 | Color signal processing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2744260B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999025123A1 (en) * | 1997-11-11 | 1999-05-20 | Sanyo Electric Co., Ltd. | Color signal processing circuit |
| WO2002060185A1 (en) * | 2001-01-23 | 2002-08-01 | Seiko Epson Corporation | Image input device and image input method |
| JP2005004767A (en) * | 2003-06-10 | 2005-01-06 | Samsung Electronics Co Ltd | Method and system for filtering noise adaptively to luminance change |
| JP2011040088A (en) * | 2003-06-10 | 2011-02-24 | Samsung Electronics Co Ltd | Method and system for luminance change-adaptive noise filtering |
-
1988
- 1988-11-22 JP JP63296731A patent/JP2744260B2/en not_active Expired - Lifetime
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999025123A1 (en) * | 1997-11-11 | 1999-05-20 | Sanyo Electric Co., Ltd. | Color signal processing circuit |
| WO2002060185A1 (en) * | 2001-01-23 | 2002-08-01 | Seiko Epson Corporation | Image input device and image input method |
| US7042465B2 (en) | 2001-01-23 | 2006-05-09 | Seiko Epson Corporation | Image input unit and image input method |
| US7230631B2 (en) | 2001-01-23 | 2007-06-12 | Seiko Epson Corporation | Image input unit and image input method |
| US7830398B2 (en) | 2001-01-23 | 2010-11-09 | Seiko Epson Corporation | Image input unit and image input method |
| US8159502B2 (en) | 2001-01-23 | 2012-04-17 | Seiko Epson Corporation | Image input unit and image input method |
| US8624917B2 (en) | 2001-01-23 | 2014-01-07 | Seiko Epson Corporation | Image input unit and image input method |
| JP2005004767A (en) * | 2003-06-10 | 2005-01-06 | Samsung Electronics Co Ltd | Method and system for filtering noise adaptively to luminance change |
| JP2011040088A (en) * | 2003-06-10 | 2011-02-24 | Samsung Electronics Co Ltd | Method and system for luminance change-adaptive noise filtering |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2744260B2 (en) | 1998-04-28 |
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