JPH0832060B2 - Color - image processing method - Google Patents

Color - image processing method

Info

Publication number
JPH0832060B2
JPH0832060B2 JP60056630A JP5663085A JPH0832060B2 JP H0832060 B2 JPH0832060 B2 JP H0832060B2 JP 60056630 A JP60056630 A JP 60056630A JP 5663085 A JP5663085 A JP 5663085A JP H0832060 B2 JPH0832060 B2 JP H0832060B2
Authority
JP
Japan
Prior art keywords
range
saturation
chroma
output device
color
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 - Lifetime
Application number
JP60056630A
Other languages
Japanese (ja)
Other versions
JPS61214893A (en
Inventor
卓 佐々木
善郎 宇田川
Original Assignee
キヤノン株式会社
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by キヤノン株式会社 filed Critical キヤノン株式会社
Priority to JP60056630A priority Critical patent/JPH0832060B2/en
Priority claimed from US06/838,785 external-priority patent/US4731662A/en
Publication of JPS61214893A publication Critical patent/JPS61214893A/en
Publication of JPH0832060B2 publication Critical patent/JPH0832060B2/en
Anticipated expiration legal-status Critical
Application status is Expired - Lifetime legal-status Critical

Links

Description

【発明の詳細な説明】 〈技術分野〉 本発明は入力カラー画像が有する彩度範囲と出力装置の再現彩度範囲が異なる場合のカラー画像処理方法に関する。 BACKGROUND OF THE INVENTION <Technical Field> The present invention relates to a color image processing method in the case where reproduction chroma range of chroma range and output device included in the input color image is different.

〈従来技術〉 従来のカラー画像処理方法では、入力カラー画像の彩度範囲を出力装置、例えばプリンタの再現彩度範囲と合わせる為に、再現彩度を超えた部分は再現彩度の最大値に圧縮していた。 The <art> conventional color image processing method, an output device saturation range of the input color image, for example in order to adjust the reproduction chroma range of the printer, the portion exceeding the reproduced chroma on the maximum value of the reproduced chroma It had been compressed.

その為入力画像の彩度の連続性が損なわれ、調子が変化した出力画像が得られていた。 Therefore continuity of saturation of the input image is impaired, the output image tone changes have been obtained.

〈目的〉 本発明は上述の如き従来技術の欠点に鑑み、入力画像の彩度分布に応じて最適なカラー処理を施こすことが可能なカラー画像処理方法の提供を目的としている。 <Object> In view of the drawbacks of the above such as the prior art, are intended to provide optimal color processing capable of straining facilities a color image processing method according to the saturation distribution of the input image.

〈実施例〉 本発明を入力R,G,Bカラー信号をハードコピーするカラープリンタに適用した例について説明する。 Enter <Example> The present invention R, G, and B color signals for example applied to a color printer for hard copy will be described.

第1図は本実施例のカラープリンタの信号処理ブロツク図である。 FIG. 1 is a signal processing block diagram of a color printer of this embodiment. 図において、11は入力R,G,B信号から輝度信号Y,色差信号(R−Y),(B−Y)を得るエンコーダで次式の処理を行う。 In the figure, 11 is an input R, G, B signals from the luminance signal Y, color difference signals (R-Y), to process the next type encoder to obtain a (B-Y).

12は色差信号(R−Y),(B−Y)から色相H,彩度Cを得る演算回路で次式の処理を行う。 12 color difference signals (R-Y), to process the next equation in arithmetic circuit for obtaining a hue H, saturation C from (B-Y).

13は各色相について彩度のヒストグラムをとる処理及び彩度変換を行うCPUである。 13 is a CPU for processing and chroma conversion takes histograms of chroma for each hue. 14はCPUの処理プログラムを格納したROM、15はヒストグラムデータ及びその他CPU 14 stores a processing program CPU ROM, 15 is a histogram data and other CPU
13の処理に必要な値を記憶するRAMである。 13 is a RAM for storing the values ​​necessary for the processing. 16は輝度信号Y,色相H,変換された彩度C′からマスキング処理を行い、イエローYe,マゼンタMa,シアンCyの各原色信号を得るマスキング回路、18Ye,18Ma,18Cyは各原色を記録する記録ヘツドである。 16 performs masking processing from the luminance signal Y, hue H, transformed chroma C ', yellow Ye, magenta Ma, masking circuit for obtaining a primary color signals of cyan Cy, 18Ye, 18Ma, 18Cy records each primary color which is a recording head.

以下、第2図のフローチヤートに従い、CPU13の処理動作について説明する。 Hereinafter, in accordance with the flow chart of FIG. 2 will be described CPU13 processing operation.

まずステツプS1で入力カラー信号の一画面を構成する全画素を対象として、各色相Hについて彩度のヒストグラム(頻度分布)をとる。 First as for all pixels constituting the one screen of the input color signal in step S1, taking a histogram of saturation (frequency distribution) for each hue H. 次にステツプS2で各色相Hについて最大彩度C(H) max ,最小彩度C(H) minを検出する。 Next, in step S2 for each hue H detects the maximum chroma C (H) max, the minimum chroma C (H) min.
そしてS3でC(H) maxとC(H) minの差と予め測定したおいたカラープリンタの各色相Hについての最大再現彩度C(H) And S3 at C (H) max and C (H) Maximum reproduction chroma C for the hue H in the color had been previously measured as the difference min printer (H)
Lとを比較する。 It is compared with the L. S3でC(H) max −C(H) min >C(H) Lの場合にはステツプS4で次式に従い、彩度の圧縮処理を行い出力彩度C′(H)を得る。 According to the following equation at step S4, in the case of C (H) max -C (H ) min> C (H) L in S3, performs compression processing of the chroma obtain the output chroma C '(H).

この様にして第3図(1)に示す如き彩度の圧縮処理が行われる。 Compression process such saturation shown in FIG. 3 in this manner (1) is performed. 従って色調の連続性が損なわれることなく彩度の圧縮が可能となる。 Thus compression of chroma is made possible without continuity of tone is impaired. 特に第3図(1)に示す彩度圧縮を行う場合には入力画像のうち、最低の彩度のレベルはそのまま出力されるので、例えば鮮やかな彩度の高い連続した色調の背景をバックに比較的彩度の低い人間の顔が撮像される画像であっても、彩度圧縮処理により人間の顔の彩度が低下し、顔色が悪くなってしまうことを未然に防止し、かつ彩度の高い背景の色調の連続性を損なうこともない。 Especially in the input image in the case of performing the saturation compression shown in FIG. 3 (1), the level of the lowest saturation is output as it is, the back color of the background continuous high e.g. vivid color saturation be an image relatively chroma low human face is captured, saturation of the human face is reduced by saturation compression process, in order to prevent the occurrence of the complexion becomes worse, chroma that there is no prejudice to the continuity of the high background of shades.

次にC(H) max −C(H) min ≦C(H) LとS3で判断され、S6でC Then it is determined by C (H) max -C (H ) min ≦ C (H) L and S3, C in S6
(H) L ≧C(H) maxと判断された場合には、第3図(2)に示す如く、入力画像の彩度範囲がプリンタの再現彩度範囲に完全に含まれるので、彩度変換を行わずに、S7でC If it is determined that (H) L ≧ C (H ) max , as shown in FIG. 3 (2), since the saturation range of the input image is completely included in the reproduction chroma range of the printer, the saturation without conversion, C in S7
(H)をそのままC(H′)として出力する。 (H) and outputs it as a C (H '). 斯かる構成により入力画像の特性をそのまま活かすことができる。 Characteristic of the input image by such a configuration can be a leverage as it is.

最後にC(H) max −C(H) min ≦C(H) Lで、C(H) L <C(H) max Finally, in C (H) max -C (H ) min ≦ C (H) L, C (H) L <C (H) max
とS6で判断された場合には、第3図(3)に示す如く、 When if it is determined in S6, as shown in FIG. 3 (3),
入力画像の最大彩度側が出力再現彩度の最大値を超えている。 Maximum saturation side of the input image is greater than the maximum value of the output reproduced chroma. この場合は彩度が大きい方に偏っているのを活かしてS9で次式に従い分布全体を移動させる。 In this case it moves the entire distribution in accordance with the following equation in S9 taking advantage of the biased towards the larger saturation.

C(H)−(C(H) max −C(H) L )→C′(H) 斯かる手法により彩度の偏りをそのまま出力画像の彩度の偏りとして再現できると共に、彩度範囲の絶対値は変化せず自然な印象を視覚に与える。 C (H) - by (C (H) max -C ( H) L) → C '(H) such technique with the bias of the saturation can be reproduced as a deviation of the saturation of directly output image, saturation range the absolute value is given to the visual a natural impression does not change.

こうしてステツプS4,S7,S9で得られたC′(H)をマスキング回路16にステツプS5,S8,S10で出力する。 Thus step S4, S7, C obtained in S9 'the (H) is output to the masking circuit 16 in step S5, S8, S10.

尚、本実施例においては各色相について彩度の変換を行ったが、色相と明度の両方について彩度の変換を行えばより正確であるが、処理が複雑となる。 Although in the present embodiment was converted chroma for each hue, but it is more accurate by performing a transformation of saturation for both hue and brightness, the processing becomes complicated.

又、輝度,色相,彩度信号としてY,H,Cを用いたが、 The luminance, hue, Y as the chroma signal, H, was used C,
それに類するものであればよく、Lab*,Luv*等を用いることもできる。 It may be one similar to it, Lab *, can also be used Luv * and the like.

又,本例では色相すべてについて処理を行ったが、特定の色相に代表させて変換処理を行ってもよい。 Moreover, processing was carried out for all hues in the present example, it may be carried out the conversion process as a representative to the particular hue.

効果 本発明に依れば入力カラー画像信号の所定色相の彩度範囲が出力装置の再現彩度範囲に含まれるか否かを予め判定し、前記入力カラー画像信号の彩度範囲が出力装置の再現彩度範囲に含まれないと判定された場合には前記入力カラー画像信号の彩度範囲を前記出力装置の再現彩度範囲内に色調の連続性が損なわれない様に圧縮して前記出力装置に出力し、前記入力カラー画像信号の彩度範囲が前記出力装置の再現彩度範囲に含まれると判定された場合には前記入力カラー画像信号の彩度範囲を圧縮することなく前記出力装置に出力しているので入力カラー画像信号の特性、彩度の状態をなるべく保存し、かつ出力装置の再現彩度範囲内で画像全体の彩度の階調を再現することが可能になり、再現彩度範囲が制限されたカラープリンタ、あ According to the present invention the input color saturation range of a predetermined color image signal whether previously determined is included in the reproduction chroma range of the output device, the saturation range of the input color image signal output device wherein when it is determined to be not included in the reproduction chroma range is compressed so as not tonal continuity is impaired saturation range of the input color image signal into the reproduction chroma range of the output device outputs output to device, the output device without compressing the saturation range of the input color image signal when the saturation range of the input color image signal is determined to be included in the reproduced chroma range of the output device since the output characteristics of the input color image signal, as far as possible save the state of saturation, and it is possible to reproduce the gradation of saturation of the entire image in the reproduction chroma range of the output device, reproduction color printer saturation range is limited, Oh るいはカラーディスプレイ装置に極めて有用である。 Rui is very useful to the color display device.

【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS

第1図は本実施例のカラープリンタの信号処理ブロツク図、第2図は第1図のCPU13の処理フローチヤート図、 Figure 1 is a signal processing block diagram of a color printer of this embodiment, FIG. 2 CPU13 processing flow chart diagram of Figure 1,
第3図は彩度の入出力ヒストグラムを示す図である。 FIG. 3 is a diagram showing the input and output histogram of saturation.

───────────────────────────────────────────────────── 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 1/60 5/91 H04N 1/40 D 5/91 H B41J 3/00 B ────────────────────────────────────────────────── ─── front page continued (51) Int.Cl. 6 identification symbol Agency Docket No. FI art display portion H04N 1/60 5/91 H04N 1/40 D 5/91 H B41J 3/00 B

Claims (1)

    【特許請求の範囲】 [The claims]
  1. 【請求項1】入力カラー画像信号の所定色相の彩度範囲が出力装置の再現彩度範囲に含まれるか否かを予め判定し、前記入力カラー画像信号の彩度範囲が出力装置の再現彩度範囲に含まれないと判定された場合には前記入力カラー画像信号の彩度範囲を前記出力装置の再現彩度範囲内に色調の連続性が損なわれない様に圧縮して前記出力装置に出力し、前記入力カラー画像信号の彩度範囲が前記出力装置の再現彩度範囲に含まれると判定された場合には前記入力カラー画像信号の彩度範囲を圧縮することなく前記出力装置に出力することを特徴とするカラー画像処理方法。 1. A input color saturation range of a predetermined color of the image signal in advance determined whether included in the reproduced chroma range of the output device, reproduction chroma of the input color image signal saturation range output device to the output device by compressing as is not impaired continuity of tone saturation range of the input color image signal into the reproduction chroma range of the output device when it is determined not to be included in the time range and outputs the output to the output device without a case where the saturation range of the input color image signal is determined to be included in the reproduced chroma range of the output device for compressing the saturation range of the input color image signal color image processing method characterized by.
JP60056630A 1985-03-21 1985-03-21 Color - image processing method Expired - Lifetime JPH0832060B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP60056630A JPH0832060B2 (en) 1985-03-21 1985-03-21 Color - image processing method

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP60056630A JPH0832060B2 (en) 1985-03-21 1985-03-21 Color - image processing method
US06/838,785 US4731662A (en) 1985-03-21 1986-03-12 Image processing method for processing an image signal differently depending on the range of an image characteristic thereof relative to the range within which an output device can reproduce the image characteristic
DE19863609049 DE3609049C3 (en) 1985-03-21 1986-03-18 The rendering method

Publications (2)

Publication Number Publication Date
JPS61214893A JPS61214893A (en) 1986-09-24
JPH0832060B2 true JPH0832060B2 (en) 1996-03-27

Family

ID=13032625

Family Applications (1)

Application Number Title Priority Date Filing Date
JP60056630A Expired - Lifetime JPH0832060B2 (en) 1985-03-21 1985-03-21 Color - image processing method

Country Status (1)

Country Link
JP (1) JPH0832060B2 (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0439954B2 (en) * 1986-08-25 1992-07-01 Tokyo Shibaura Electric Co
JPH0669438B2 (en) * 1987-04-24 1994-09-07 株式会社東芝 Endoscope apparatus
JPH06101854B2 (en) * 1987-11-17 1994-12-12 三菱電機株式会社 Color reproduction processing method
JPH0241271A (en) * 1988-08-01 1990-02-09 Fuji Xerox Co Ltd Color image forming apparatus
JP2714027B2 (en) * 1988-08-31 1998-02-16 キヤノン株式会社 Color image processing apparatus and a color image processing method
JP2698493B2 (en) * 1991-09-20 1998-01-19 三菱電機株式会社 Saturation adjustment apparatus
JP2598601B2 (en) * 1992-04-06 1997-04-09 ライノタイプ−ヘル アクチエンゲゼルシャフト Analysis and correction method of the original image gradation

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5633700B2 (en) * 1975-06-18 1981-08-05
JPS6326585B2 (en) * 1979-02-28 1988-05-30 Fuji Photo Film Co Ltd
JPH0151828B2 (en) * 1979-04-23 1989-11-06 Dainippon Screen Mfg
JPS5633700A (en) * 1979-08-28 1981-04-04 Katsuragi Sangyo Kk Speaker box
JPS56128947A (en) * 1980-03-13 1981-10-08 Dainippon Screen Mfg Co Ltd Method of setting highlight and shadow point density value of original picture to picture scanning recorder
JPS6335149B2 (en) * 1981-06-19 1988-07-13 Hitachi Ltd
JPH0226836B2 (en) * 1981-12-05 1990-06-13 Dainippon Insatsu Kk
JPH0417500B2 (en) * 1982-04-12 1992-03-26 Canon Kk
DE3315616C2 (en) * 1983-04-29 1991-08-14 Agfa-Gevaert Ag, 5090 Leverkusen, De
JPH06101807B2 (en) * 1984-08-10 1994-12-12 ソニー株式会社 Compression circuit of an image signal

Also Published As

Publication number Publication date
JPS61214893A (en) 1986-09-24

Similar Documents

Publication Publication Date Title
AU727165B2 (en) Gamut correction with color separation and methods and apparatuses for performing same
US7292371B2 (en) Image processing apparatus, image processing method, image processing program recording medium, color adjustment method, color adjustment device, and color adjustment control program recording medium
US5619347A (en) Apparatus for calculating a degree of white balance adjustment for a picture
US6608926B1 (en) Image processing method, image processing apparatus and recording medium
US6668079B2 (en) Method of processing image signal
US5420938A (en) Image processing apparatus
JP2748678B2 (en) Gradation correction method and gradation correction device
US7289663B2 (en) Producing an extended color gamut luminance-chrominance digital image from a captured image
US6243133B1 (en) Method for automatic scene balance of digital images
EP1006483B1 (en) Color data converting method
JP2004192614A (en) Image processing device, image processing method, program and recording medium
US6975437B2 (en) Method, apparatus and recording medium for color correction
JP2755935B2 (en) How to create five colors to 7-color printing plate used in the multicolor printing machine
JP3102808B2 (en) How to map a full-color image to a highlight color image
US6980326B2 (en) Image processing method and apparatus for color correction of an image
US5933253A (en) Color area compression method and apparatus
US20060285137A1 (en) Image processing method and apparatus
EP0675636B1 (en) Extended density color printing
US5774238A (en) Color conversion for realizing color reproduction without using color reproduction model
DE3609049C3 (en) The rendering method
EP1487219A1 (en) Image processing device, image processing method, and image processing device manufacturing method
US7454056B2 (en) Color correction device, color correction method, and color correction program
US4931864A (en) Image forming apparatus which performs gamma correction on the basis of a cumulative frequency distribution produced from a histogram of image data representing a selected area of an image
JP4250214B2 (en) Color conversion method
US6310696B1 (en) Color gamut displaying method, an image processing method, and apparatus utilizing these methods

Legal Events

Date Code Title Description
EXPY Cancellation because of completion of term