JPH07288708A - Picture processing method - Google Patents
Picture processing methodInfo
- Publication number
- JPH07288708A JPH07288708A JP7067785A JP6778595A JPH07288708A JP H07288708 A JPH07288708 A JP H07288708A JP 7067785 A JP7067785 A JP 7067785A JP 6778595 A JP6778595 A JP 6778595A JP H07288708 A JPH07288708 A JP H07288708A
- Authority
- JP
- Japan
- Prior art keywords
- saturation
- color
- reproduction
- range
- hues
- 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
Landscapes
- Color, Gradation (AREA)
- Color Electrophotography (AREA)
- Processing Or Creating Images (AREA)
- 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】本発明は入力画像データに対し
て、色空間圧縮を行う画像処理方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method for performing color space compression on input image data.
【０００２】[0002]
【従来の技術】画像形成装置は、記録材の特性等に起因
する出力特性により、入力される全ての色を忠実に再現
することができない。即ち、画像形成装置の色再現範囲
外の色は忠実に再現することができない。2. Description of the Related Art An image forming apparatus cannot faithfully reproduce all input colors due to output characteristics resulting from characteristics of recording materials. That is, colors outside the color reproduction range of the image forming apparatus cannot be faithfully reproduced.
【０００３】従来は、色再現範囲外の色を示すカラーデ
ータが入力された場合は、入力画像の特徴を全く考慮せ
ず適当に変換し、画像形成していた。Conventionally, when color data indicating a color outside the color reproduction range is input, it is appropriately converted without consideration of the characteristics of the input image to form an image.
【０００４】[0004]
【発明が解決しようとする課題】以上のように、従来の
方法では色再現範囲外の色がＹの色の色味と全く違う色
になって画像形成されてしまい、入力画像の色あいが崩
れてしまうという問題があった。As described above, according to the conventional method, the color outside the color reproduction range becomes a color completely different from the tint of the color of Y and an image is formed, and the hue of the input image is destroyed. There was a problem that it would end up.
【０００５】本発明は上述の点に鑑みてなされたもので
あり、入力画像の色あいを保つように、色再現範囲外の
色を、色再現範囲内の色に色空間圧縮することができる
画像処理方法を提供することを目的とする。The present invention has been made in view of the above points, and an image in which a color outside the color reproduction range can be color space compressed into a color within the color reproduction range so as to maintain the color tone of the input image. It is intended to provide a processing method.
【０００６】[0006]
【課題を解決するための手段及び作用】上記目的を達成
するために本願発明の画像処理方法は以下の構成を有す
る。To achieve the above object, the image processing method of the present invention has the following configuration.
【０００７】入力画像に関する所定の複数の各色相にお
ける高彩度データを該入力画像の色分布を示すデータと
して抽出し、前記抽出された所定の複数の各色相におけ
る高彩度データと画像出力手段の再現彩度範囲に関する
該複数の各色相における高彩度データに基づき前記入力
画像に対して色空間圧縮する。High saturation data in a plurality of predetermined hues related to the input image is extracted as data indicating the color distribution of the input image, and the high saturation data in the extracted predetermined plurality of hues and the reproduction saturation of the image output means are extracted. Color space compression is performed on the input image based on the high saturation data in each of the plurality of hues related to the range.
【０００８】[0008]
【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。DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is applied to a color printer for making hard copy of input R, G, B color signals will be described.
【０００９】図１は本実施例のカラープリンタの信号処
理ブロック図である。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。FIG. 1 is a signal processing block diagram of the color printer of this embodiment. In the figure, 11 is input R, G,
B signal to luminance signal Y, color difference signals (RY), (B-
The following equation is processed by the encoder that obtains Y).
【００１０】[0010]
【外１】 [Outer 1]
【００１１】１２は色差信号（Ｒ−Ｙ），（Ｂ−Ｙ）か
ら色相Ｈ，再度Ｃを得る演算回路で次式の処理を行う。Reference numeral 12 denotes an arithmetic circuit for obtaining the hue H and C again from the color difference signals (RY) and (BY), and performs the processing of the following equation.
【００１２】[0012]
【外２】 [Outside 2]
【００１３】１３は各色相について彩度のヒストグラム
をとる処理及び再度変換を行うＣＰＵである。１４はＣ
ＰＵ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ＣＰＵ１３の処理に必要な値を
記憶するＲＡＭである。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Ｙ
ｅ，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
記録する記録ヘッドである。Reference numeral 13 denotes a CPU which performs a process for obtaining a histogram of saturation for each hue and conversion again. 14 is C
A ROM storing a processing program for the PU and a RAM 15 for storing the histogram data and other values necessary for the processing of the CPU 13. 16 performs masking processing from the luminance signal Y, the hue H, and the converted saturation C, and the yellow Y
A masking circuit for obtaining primary color signals of e, magenta Ma, and cyan Cy, and 18Ye, 18Ma, and 18Cy are recording heads for recording the primary colors.
【００１４】以下、図２のフローチャートに従い、ＣＰ
Ｕ１３の処理動作について説明する。Below, according to the flow chart of FIG.
The processing operation of U13 will be described.
【００１５】まずステップ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。次にステップＳ
２で各色相Ｈについて最大彩度Ｃ（Ｈ）ｍａｘ，最小再
度Ｃ（Ｈ）ｍｉｎを検出する。そして、Ｃ（Ｈ）L＜Ｃ
（Ｈ）ｍａｘとＳ６で判断された場合には、図３（３）
に示す如く、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。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。First, in step S1, a histogram (frequency distribution) of saturation is obtained for each hue H for all pixels constituting one screen of the input color signal. Then step S
In step 2, the maximum saturation C (H) max and the minimum again C (H) min are detected for each hue H. And C (H) L <C
If (H) max is determined in S6, the process in FIG.
As shown in, the maximum saturation side of the input image exceeds the maximum value of the output reproduction saturation. In this case, the entire distribution is moved according to the following equation in S9 by taking advantage of the bias toward the larger saturation.
【００１６】 Ｃ（Ｈ）−（Ｃ（Ｈ）ｍａｘ−Ｃ（Ｈ）L）→Ｃ（Ｈ）C (H) − (C (H) max−C (H) L ) → C (H)
【００１７】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。By such a method, the bias of saturation can be reproduced as it is as the bias of saturation of the output image, and the absolute value of the saturation range does not change, giving a natural impression to the visual sense.
【００１８】こうしてステップＳ４，Ｓ７，Ｓ９で得ら
れたＣ（Ｈ）をマスキング回路１６にステップＳ５，Ｓ
８，Ｓ１０で出力する。The C (H) thus obtained in steps S4, S7 and S9 is supplied to the masking circuit 16 in steps S5 and S.
8, output at S10.
【００１９】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。In the present embodiment, the saturation conversion is performed for each hue, but if the saturation conversion is performed for both hue and lightness, it is more accurate, but the process becomes complicated.
【００２０】又、輝度，色相，彩度信号としてＹ，Ｈ，
ＣＳ３でＣ（Ｈ）ｍａｘとＣ（Ｈ）ｍｉｎの差と予め測
定して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）Lとを比較する。Ｓ３でＣ（Ｈ）ｍａ
ｘ−Ｃ（Ｈ）ｍｉｎ＞Ｃ（Ｈ）Lの場合にはステップＳ
４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。In addition, Y, H, and
The difference between C (H) max and C (H) min in CS3 is compared with the maximum reproduced saturation C (H) L for each hue H of the color printer measured in advance. C (H) ma in S3
If x−C (H) min> C (H) L , step S
In step 4, the saturation is compressed according to the following equation, and the output saturation C
(H) is obtained.
【００２１】[0021]
【外３】 [Outside 3]
【００２２】この様にして図３（１）に示す如き彩度の
圧縮処理が行われる。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。In this way, the saturation compression processing as shown in FIG. 3A is performed. Therefore, the saturation can be compressed without impairing the continuity of the color tone.
【００２３】次にＣ（Ｈ）ｍａｘ−Ｃ（Ｈ）ｍｉｎ≦Ｃ
（Ｈ）LとＳ３で判断され、Ｓ６でＣ（Ｈ）L≧Ｃ（Ｈ）
ｍａｘと判断された場合には、図３（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（Ｈ）を
そのままＣ（Ｈ）として出力する。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。Next, C (H) max-C (H) min≤C
(H) L and S3 are judged, and in S6 C (H) L ≧ C (H)
If it is determined to be max, as shown in FIG.
Since the saturation range of the input image is completely included in the reproduction saturation range of the printer, C (H) is directly output as C (H) in S7 without performing the saturation conversion. With such a configuration, the characteristics of the input image can be used as they are.
【００２４】最後にＣ（Ｈ）ｍａｘ−Ｃ（Ｈ）ｍｉｎ≦
Ｃ（Ｈ）Lを用いたが、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。Finally, C (H) max-C (H) min≤
Although C (H) L is used, any similar material may be used, and Lab *, Luv *, etc. may be used.
【００２５】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。Further, in this example, the processing is performed for all the hues, but the conversion processing may be performed by representing a specific hue.
【００２６】以上の如く本実施例によれば、入力カラー
画像の特性を活かしてカラー画像を再現することが可能
となり、再現彩度範囲が制限されたカラープリンタ、或
はカラーディスプレイ装置に極めて有効である。As described above, according to the present embodiment, it is possible to reproduce a color image by utilizing the characteristics of the input color image, and it is extremely effective for a color printer or a color display device having a limited reproduction saturation range. Is.
【００２７】[0027]
【発明の効果】以上のように本願発明によれば、入力画
像の色あいを保つように、色再現範囲外の色を色再現範
囲内の色に色空間圧縮することができる。As described above, according to the present invention, the color outside the color reproduction range can be color space compressed into the color within the color reproduction range so as to maintain the color tone of the input image.
【００２８】即ち、色再現範囲外の色を含む入力画像に
対して、色あいの近い、高画質の画像をカラープリンタ
等、画像出力装置で出力することができる。That is, an image output device such as a color printer can output a high-quality image having a close color tone to an input image including a color outside the color reproduction range.
【図１】本実施例のカラープリンタのブロック図。FIG. 1 is a block diagram of a color printer of this embodiment.
【図２】ＣＰＵ１３の処理フローチャート。FIG. 2 is a processing flowchart of a CPU 13.
【図３】彩度の入出力ヒストグラムの１例を示す図。FIG. 3 is a diagram showing an example of an input / output histogram of saturation.
１１ エンコーダ １３ ＣＰＵ １６ マスキング回路 11 encoder 13 CPU 16 masking circuit
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 9/79 // Ｂ４１Ｊ 2/525 Ｇ０３Ｇ 15/01 １１５ Ｇ０６Ｆ 15/66 ３１０ Ｈ０４Ｎ 1/46 Ｚ 9/79 Ｈ Ｂ４１Ｊ 3/00 Ｂ Continuation of front page (51) Int.Cl. 6 Identification number Office reference number FI technical display location H04N 9/79 // B41J 2/525 G03G 15/01 115 G06F 15/66 310 H04N 1/46 Z 9/79 H B41J 3/00 B
Claims (1)
おける高彩度データを該入力画像の色分布を示すデータ
として抽出し、 前記抽出された所定の複数の各色相における高彩度デー
タと画像出力手段の再現彩度範囲に関する該複数の各色
相における高彩度データに基づき前記入力画像に対して
色空間圧縮する画像処理方法。1. High saturation data in each of a plurality of predetermined hues of an input image is extracted as data indicating a color distribution of the input image, and the high saturation data in each of the plurality of the predetermined plurality of extracted hues and reproduction of an image output means. An image processing method for performing color space compression on the input image based on high saturation data in each of the plurality of hues related to the saturation range.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7067785A JP2567214B2 (en) | 1995-03-27 | 1995-03-27 | Image processing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7067785A JP2567214B2 (en) | 1995-03-27 | 1995-03-27 | Image processing method |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60056630A Division JPH0832060B2 (en) | 1985-03-21 | 1985-03-21 | Color image processing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07288708A true JPH07288708A (en) | 1995-10-31 |
| JP2567214B2 JP2567214B2 (en) | 1996-12-25 |
Family
ID=13354968
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7067785A Expired - Lifetime JP2567214B2 (en) | 1995-03-27 | 1995-03-27 | Image processing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2567214B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100438159B1 (en) * | 2002-03-13 | 2004-07-01 | 삼성전자주식회사 | Color signal processing device capable of storing color gamut efficiently and method using the same |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3914168B2 (en) | 2003-04-08 | 2007-05-16 | オリンパス株式会社 | Imaging system, image processing program |
-
1995
- 1995-03-27 JP JP7067785A patent/JP2567214B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100438159B1 (en) * | 2002-03-13 | 2004-07-01 | 삼성전자주식회사 | Color signal processing device capable of storing color gamut efficiently and method using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2567214B2 (en) | 1996-12-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |