JPH0818809A - Color correction method - Google Patents
Color correction methodInfo
- Publication number
- JPH0818809A JPH0818809A JP6148034A JP14803494A JPH0818809A JP H0818809 A JPH0818809 A JP H0818809A JP 6148034 A JP6148034 A JP 6148034A JP 14803494 A JP14803494 A JP 14803494A JP H0818809 A JPH0818809 A JP H0818809A
- Authority
- JP
- Japan
- Prior art keywords
- correction
- color
- hue
- groups
- object area
- 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.)
- Pending
Links
Landscapes
- Image Processing (AREA)
- Facsimile Image Signal Circuits (AREA)
- Color Image Communication Systems (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明はカラー画像処理技術に用
いられる色補正方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color correction method used in color image processing technology.
【0002】[0002]
【従来の技術】従来、例えば特開平4−369969号
公報に示されるように、小規模のハードウェアで有彩色
を正しく再現でき、且つ無彩色に色がつかないように、
画像入力端子に入力された入力信号の表す色がどの程度
2次色に近いか、あるいは3次色に近いかを判定し、入
力信号の2次色の度合、あるいは3次色の度合を表す値
を出力する類似度判定回路と、この類似度に基づいて色
補正のための所定のマトリクス係数を発生する係数発生
回路と、これら係数と前記入力信号とのマトリクス演算
を実行しその結果を補正語の色信号として出力端子から
出力するマトリクス演算回路からなる色補正回路が知ら
れている。2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Unexamined Patent Publication No. 4-369969, chromatic colors can be correctly reproduced by small-scale hardware, and achromatic colors do not appear.
It is determined whether the color represented by the input signal input to the image input terminal is close to the secondary color or the tertiary color, and the degree of the secondary color of the input signal or the degree of the tertiary color is represented. A similarity determination circuit that outputs a value, a coefficient generation circuit that generates a predetermined matrix coefficient for color correction based on this similarity, and a matrix operation of these coefficients and the input signal is executed and the result is corrected. 2. Description of the Related Art A color correction circuit including a matrix calculation circuit that outputs a word color signal from an output terminal is known.
【0003】[0003]
【発明が解決しようとする課題】しかしながら上記従来
技術では、色空間分割による線形変換を用いた色補正に
おいて問題となる領域境界での不連続性ができないとい
う問題点があった。However, the above-mentioned conventional technique has a problem in that discontinuity at a region boundary, which is a problem in color correction using linear conversion by color space division, cannot be performed.
【0004】本発明は上記問題点に鑑みなされたもので
あり、入力信号の近接2グループ係数の加重平均を用い
ることにより斯かる問題点を解決することを目的とす
る。The present invention has been made in view of the above problems, and an object of the present invention is to solve such problems by using a weighted average of adjacent 2 group coefficients of an input signal.
【0005】[0005]
【課題を解決するための手段】本発明は、入力されたカ
ラー画像信号から色補正の対象となる領域の色相を計算
し、得られた色相データから互いに近接する2グループ
A、Bを決定し、決定された両グループA、Bの補正係
数αA、αBと前記対象領域から各グループの中心まで
の色相距離lA、lBとによって加重平均係数αを算出
し、この加重平均αによって前記対象領域の画像信号を
補正する色補正方法である。According to the present invention, the hue of a region to be color-corrected is calculated from an input color image signal, and two groups A and B close to each other are determined from the obtained hue data. A weighted average coefficient α is calculated from the determined correction coefficients αA and αB of both groups A and B and the hue distances 1A and 1B from the target area to the center of each group, and the weighted average α of the target area is calculated using the weighted average α. This is a color correction method for correcting an image signal.
【0006】なお、前記加重平均係数αは、The weighted average coefficient α is
【0007】[0007]
【数2】 [Equation 2]
【0008】よって算出される。[0008]
【0009】[0009]
【作用】上記構成によれば、経済効果の高い線形変換を
用いながら、原画像のもつ色分布の連続性を損なうこと
なく色補正が行える。According to the above construction, the color correction can be performed without impairing the continuity of the color distribution of the original image while using the linear conversion having a high economic effect.
【0010】[0010]
【実施例】以下本発明の色補正方法をその一実施例につ
いて図面に基き詳細に説明する。図1は本補正方法のア
ルゴリズムを示すフローチャートである。同図において
ステップS1で補正の対象となる領域に対して入力され
たRGB信号から、色相計算をステップS2で行う。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color correction method according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a flowchart showing the algorithm of this correction method. In the figure, hue calculation is performed in step S2 from the RGB signals input to the area to be corrected in step S1.
【0011】この色相計算は図2のアルゴリズムに示す
ように求められる。まず、ステップS21でR、G、B
信号を入力し、入力されたR、G、B信号がどの程度等
しいかを数3に基づいて算出する(ステップS21〜2
3)。This hue calculation is obtained as shown in the algorithm of FIG. First, in step S21, R, G, B
A signal is input, and the degree to which the input R, G, and B signals are equal is calculated based on Equation 3 (steps S21 to S2).
3).
【0012】[0012]
【数3】 (Equation 3)
【0013】ここでMAX( )、MIN( )は夫々
括弧内の引数の最大値及び最小値をその値とする関数を
表す。次に算出されたdel、max及び入力信号R、
G、Bを用いてステップ24においてr、g、bを数4
に基づき算出する。Here, MAX () and MIN () represent functions having the maximum and minimum values of the arguments in parentheses, respectively. Next, the calculated del, max and the input signal R,
In step 24 using G and B, r, g, and b are given by
Calculate based on
【0014】[0014]
【数4】 [Equation 4]
【0015】こうして得られたr、gと前記maxの値
とが等しいか否かをステップS25、S26によって夫
々判定し、max=rのときは色相HをH=b−g(ス
テップS29)とし、max=gのときは色相HをH=
2+r−b(ステップS28)とし、いずれでもない時
には色相HをH=4+g−rとして補正対象領域の色相
を計算により求める。It is judged in steps S25 and S26 whether or not the values r and g thus obtained are equal to the value of max, respectively. When max = r, the hue H is set to H = b-g (step S29). , Max = g, the hue H is H =
2 + r−b (step S28), and when neither is the case, the hue H is set to H = 4 + g−r, and the hue of the correction target region is calculated.
【0016】ステップS3では、前記補正対象領域を含
む互いに近接する2グループA、Bを決定する。そして
このグループA、Bそれぞれの前記色相Hに対応した色
補正係数αA、αBを求め(ステップS4及びS5)、
さらに前記補正対象領域から各グループA、Bまでの距
離(色相距離)lA、lBを計算によって求める。In step S3, two groups A and B that include the correction target area and are close to each other are determined. Then, the color correction coefficients αA and αB corresponding to the hues H of the groups A and B are obtained (steps S4 and S5),
Further, the distances (hue distances) 1A and 1B from the correction target area to the groups A and B are calculated.
【0017】そしてステップS7で前記補正対象領域の
補正係数αを図3に示すような加重平均の手法を用いて
数4により求める。Then, in step S7, the correction coefficient α of the area to be corrected is obtained by the equation 4 using the weighted average method as shown in FIG.
【0018】[0018]
【数5】 (Equation 5)
【0019】なお、前記色補正係数αA、αBは実験等
で得られた各グループの予め格納されている固有補正係
数を用い、前記色相Hから求める。また前記色相距離l
A、lBは、例えばグループAの中心の色相が100
°、グループBの中心の色相が200°、補正対象の色
相が160°のとき、lA=160−100=60°、
lB=200−160=40°というように求める。The color correction coefficients αA and αB are obtained from the hue H by using prestored unique correction coefficients of each group obtained through experiments or the like. Also, the hue distance l
A and IB have, for example, a central hue of group A of 100.
°, when the central hue of the group B is 200 ° and the hue to be corrected is 160 °, IA = 160-100 = 60 °,
1B = 200−160 = 40 °.
【0020】補正係数αが求まると、このαを用いて補
正対象領域の色補正を行う(ステップS8)。補正の方
法としては線形1次変換の場合は、入力信号R、G、B
を3×4行列のαを用いて数5によりR’、G’、B’
に変換する方法や、入力信号R、G、B及びR2 、G
2 、B2 、RG、GB、BRを3×10行列のαを用い
て数6によりR’、G’、B’に変換する方法等があ
る。When the correction coefficient α is obtained, the color of the correction target area is corrected using this α (step S8). As a correction method, in the case of linear first-order conversion, input signals R, G, B
R ′, G ′, B ′ according to Equation 5 using α of 3 × 4 matrix
Input signal R, G, B and R 2 , G
There is a method of converting 2 , B 2 , RG, GB, and BR into R ′, G ′, and B ′ by Equation 6 using α of a 3 × 10 matrix.
【0021】[0021]
【数6】 (Equation 6)
【0022】[0022]
【数7】 (Equation 7)
【0023】このようにして得られたR’、G’、B’
を出力する。R ', G', B'obtained in this way
Is output.
【0024】[0024]
【発明の効果】本発明は以上の説明の如く、補正対象領
域の色補正をその近傍の2つのグループの領域の補正係
数を用いて加重平均により算出した補正係数を用いて行
うことにより、経済効果の高い線形変換を用いながら、
原画像のもつ色分布の連続性を損なうことなく、低コス
トで高精度の色補正を実現することが可能となる。As described above, according to the present invention, the color correction of the correction target area is performed by using the correction coefficient calculated by the weighted average using the correction coefficients of the two groups of areas in the vicinity of the correction area. While using a highly effective linear transformation,
It is possible to realize highly accurate color correction at low cost without impairing the continuity of the color distribution of the original image.
【図1】本発明の色補正方法のアルゴリズムを示すフロ
ーチャートである。FIG. 1 is a flowchart showing an algorithm of a color correction method of the present invention.
【図2】色相計算のアルゴリズムを示すフローチャート
である。FIG. 2 is a flowchart showing an algorithm of hue calculation.
【図3】加重平均の概念を示す図である。FIG. 3 is a diagram showing a concept of weighted average.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 FI 技術表示箇所 H04N 1/46 Z ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Office reference number FI technical display location H04N 1/46 Z
Claims (2)
対象となる領域の色相を計算し、得られた色相データか
ら互いに近接する2グループA、Bを決定し、決定され
た両グループA、Bの補正係数αA、αBと前記対象領
域から各グループの中心までの色相距離lA、lBとに
よって加重平均係数αを算出し、この加重平均αによっ
て前記対象領域の画像信号を補正する色補正方法。1. A hue of an area to be color-corrected is calculated from an input color image signal, two groups A and B adjacent to each other are determined from the obtained hue data, and both determined groups A, A color correction method of calculating a weighted average coefficient α by the correction coefficients αA and αB of B and the hue distances 1A and 1B from the target area to the center of each group, and correcting the image signal of the target area by the weighted average α. .
正方法。2. The weighted average coefficient α is 2. The color correction method according to claim 1, wherein the color correction method is calculated.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6148034A JPH0818809A (en) | 1994-06-29 | 1994-06-29 | Color correction method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6148034A JPH0818809A (en) | 1994-06-29 | 1994-06-29 | Color correction method |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0818809A true JPH0818809A (en) | 1996-01-19 |
Family
ID=15443642
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP6148034A Pending JPH0818809A (en) | 1994-06-29 | 1994-06-29 | Color correction method |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0818809A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005323376A (en) * | 2004-05-06 | 2005-11-17 | Samsung Electronics Co Ltd | Apparatus and method for adjusting primary color component of image, and computer-readable recording medium for recording program therefor |
KR100791375B1 (en) * | 2005-12-19 | 2008-01-07 | 삼성전자주식회사 | Apparatus and method for color correction |
-
1994
- 1994-06-29 JP JP6148034A patent/JPH0818809A/en active Pending
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005323376A (en) * | 2004-05-06 | 2005-11-17 | Samsung Electronics Co Ltd | Apparatus and method for adjusting primary color component of image, and computer-readable recording medium for recording program therefor |
KR100791375B1 (en) * | 2005-12-19 | 2008-01-07 | 삼성전자주식회사 | Apparatus and method for color correction |
US7720280B2 (en) | 2005-12-19 | 2010-05-18 | Samsung Electronics Co., Ltd. | Color correction apparatus and method |
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