JP3738807B2 - Image processing apparatus and image processing method - Google Patents

Description

のような演算により実現することができる。なお、この式において、変換用行列係数α１１〜α３９及びβ１〜β３は、画像入力部１の色読取特性により実験的に予め設計されている数値である。
【００４８】
絵／文字分離部１３は、各画素が絵柄を構成する画素であるのか、あるいは文字を構成する画素であるのかを識別し、その識別結果を示す信号（以下、Ｓｅｇ−Ｔａｇ信号）を出力する。この絵／文字分離部１３は、抽出手段に対応するものである。また、識別結果を示すＳｅｇ−Ｔａｇ信号は、属性情報の一つである画素情報に対応するものである。
【００４９】
図４は、絵／文字分離部の一例を示すブロック構成図である。図中、２１は文字抽出部、２２は網点抽出部、２３は論理和演算部、２４は収縮部、２５は膨張部、２６は論理積演算部、２７は色／黒判定部、２８は結合部である。絵／文字分離部１３は、画像内の文字画素を抽出し絵柄及び背景部と分離する。上述のように、絵／文字分離部１３では、入力されるＬ^* ａ^* ｂ^* 信号を受け取り、識別結果として２ビット／画素のｓｅｇ−Ｔａｇ信号を出力する。絵／文字分離部１３では、明度信号Ｌ^* は文字抽出部２１及び網点描出部２２へ入力される。文字抽出部２１では、各画素が文字画素であるか否かを示す２値信号を生成する。文字抽出部２１は、画像内の文字、線画、ソリッド（塗り潰し）など、階調レベルの高い要素を抽出する。この文字抽出部２１は、例えば所定閾値による固定２値化処理結果と周辺画素平均値を閾値とする浮動２値化処理結果の論理和を求めることにより実現することができる。同様に網点抽出部２２では、各画素が網点画素であるか否かを示す２値信号を生成する。この網点抽出部２２は、例えば特願平９−２３１３６１号に開示されているように、２値化した画像信号の疎密や周期性により、注目画素が網点領域であるか否かを判定するように構成することができる。
【００５０】
このようにして得られた各画素２値の文字信号及び網点信号の論理和を論理和演算部２３で求めた後、所定サイズの収縮及び膨張処理を収縮部２４、膨張部２５で行う。収縮部２４は、例えば３１×３１（副走査×主走査）サイズのウインドウを用い、ウインドウ内の画素に対して論理積演算を行うことにより収縮処理を行うことができる。また膨張部２５は、例えば４９×４９サイズのウインドウを用い、ウインドウ内の画素に対して論理和演算を行うことにより膨張処理を行うことができる。なお、収縮部２４および膨張部２５において用いるウインドウのサイズは任意である。
【００５１】
さらに、膨張部２５により膨張処理を行った後の信号の否定と、論理和演算部２３から出力される文字信号と網点信号の論理和信号との論理積を論理積演算部２６で演算する。これによって、文字画素を示す１ビット／画素の文字識別信号を生成する。
【００５２】
また絵／文字分離部１３では、Ｌ^* ａ^* ｂ^* 信号は色／黒判定部２７へ入力される。色／黒判定部２７では、入力されるＬ^* ａ^* ｂ^* 信号と各信号に対する所定の閾値との比較によって各画素が有彩色であるか無彩色であるかを判定し、１ビット／画素の色／黒識別信号を生成する。そして、論理積演算部２６から出力される文字識別信号と、色／黒判定部２７から出力される色／黒識別信号を結合部２８で合成し、３類型を示す２ビット／画素のＳｅｇ−Ｔａｇ信号が生成される。図５は、Ｓｅｇ−Ｔａｇ信号の一例の説明図である。Ｓｅｇ−Ｔａｇ信号は、図５に示すように２ビット／画素の値により、文字以外、黒文字、色文字の３類型を示す。
【００５３】
図２に戻り、画像変倍部１４は、色空間変換部１２から出力されるＬ^* ａ^* ｂ^* 信号を受けて、主走査方向に対して１次元の拡大、縮小を行う。この画像変倍部１４における主走査方向の拡大、縮小と、画像入力部１における副走査方向の走査速度制御と合わせて、原稿画像の２次元の拡大、縮小が実現される。画像変倍部１４における拡大、縮小は、例えば公知の線形補間演算などを用いることができる。なお、この画像変倍部１４は、画像前処理手段に対応する。画像前処理手段は、画像の変倍処理以外の処理であってもよい。
【００５４】
Ｔａｇ信号変倍部１５は、画像変倍部１４にて行われる画像の拡大、縮小処理と同じ変倍率で、Ｔａｇ信号に対して主走査方向の拡大、縮小処理を行う。拡大、縮小方法としては、例えば公知の単純変倍手法（零次ホールド法）などを用いて実現することができる。ここで、図２に示すＡｒｅａ−Ｔａｇ信号は、操作者が図示しないユーザインタフェースや編集用デジタイザを使用して原稿及び複写作業に対して行った設定を示すＴａｇ信号（属性情報）である。図６は、Ａｒｅａ−Ｔａｇ信号の一例の説明図である。ここでは図６に示すように、それぞれ２ビット／画素で“カラーモード”及び“原稿タイプ”を表す信号としている。カラーモードとしては４色（ＹＭＣＫ）を使用した画像形成、３色（ＹＭＣ）を使用した画像形成、あるいは白黒画像の形成を指定することができる。また原稿タイプとしては、文字／写真混在原稿、文字原稿、写真原稿、地図原稿などを指定することができる。Ｔａｇ信号変倍部１５は、絵／文字分離部１３から出力されるＳｅｇ−Ｔａｇ信号とともに、このＡｒｅａ−Ｔａｇ信号に対しても、画像変倍部１４と同じ変倍率で拡大、縮小処理を行う。なお、このＴａｇ信号変倍部１５は、属性前処理手段に対応する。属性前処理手段は、画像の変倍処理以外の処理であってもよく、画像前処理手段と同じ処理を行うものであればよい。
【００５５】
以上のような構成により、前段画像処理部３は、画像入力部１よりＲＧＢ信号を受け取り、Ｌ^* ａ^* ｂ^* 信号及びＴａｇ信号（Ｓｅｇ−Ｔａｇ信号、Ａｒｅａ−Ｔａｇ信号）を出力する。
【００５６】
図２の原稿検知部１６は、原稿の大きさや位置を検知したり、白黒原稿かカラー原稿かを判定するなど、コピー動作に必要とされる情報を原稿画像から抽出する。例えば、原稿読み込み走査に先立って行われる予備走査時にそれらの情報を抽出し、制御部６へ必要な情報を送出することができる。
【００５７】
制御部６は操作者が図示しない操作部より入力するコピー条件と、原稿検知部１６により原稿画像から抽出した情報に基づいて、倍率設定や白黒／カラー判別、用紙選択、トレイ選択などの自動機能を実現する。
【００５８】
図７は、後段画像処理部４の一例を示すブロック構成図である。図中、３１は色空間変換部、３２は空間補正部、３３は階調補正部、３４は中間調生成部、３５はＴａｇ信号生成部である。このうち、色空間変換部３１、空間補正部３２、階調補正部３３、中間調生成部３４は画像後処理手段に対応し、Ｔａｇ信号生成部３５は制御信号生成手段に対応する。なお画像後処理手段はこれらの処理部のほか、他の各種の処理手段を有していてよい。
【００５９】
色空間変換部３１は後段画像処理部４に入力されてくるＬ^* ａ^* ｂ^* 信号から、画像出力部２で印字に使用するＹ／Ｍ／Ｃ／Ｋ信号を印字色サイクルに従って順次生成する。図８は、色空間変換部３１の一例を示す概略構成図である。図中、４１〜４３は色補正部、４４，４５はセレクタである。色空間変換部３１は、この例では色補正部４１、色補正部４２、色補正部４３及びセレクタ４４、４５より構成されている。ここで、色補正部４１、色補正部４２、色補正部４３は、それぞれ異なる色補正係数が設定されており、入力されるＬ^* ａ^* ｂ^* 信号に対してそれぞれ設定されている色補正係数に従って色補正処理を行い、Ｙ／Ｍ／Ｃ／Ｋ信号を生成する。
【００６０】
ここで、各色補正部４１〜４３は、例えば次のように構成することができる。まず、色補正部４１が出力するＹ／Ｍ／Ｃ／Ｋ信号は、４色再現用の色補正が行われたＹ／Ｍ／Ｃ／Ｋ信号であり、原稿タイプが写真及び文字／写真の時に使用される。色補正部４２が出力するＹ／Ｍ／Ｃ／Ｋ信号も同様に４色再現用の色補正が行われたＹ／Ｍ／Ｃ／Ｋ信号であるが、原稿タイプが文字及び地図の時に使用される。ここで、写真及び文字／写真用の色補正は、原稿に対して忠実な再現を与える標準的な色補正であり、また写真の再現において粒状性の低下を生じないようにＹＭＣ信号をＫ信号に置き換える割合（以下、ＵＣＲ率と呼ぶ）が５０％程度に設定される。一方、文字及び地図用の色補正は、グラフィクス原稿やビジネス文書を想定した色補正であり、原稿に対してやや鮮やかでハイコントラストな再現を行うとともに、グレイバランスを保持するように９５％程度のＵＣＲ率が設定される。色補正部４３が出力する信号は、Ｙ、Ｍ、Ｃの３色再現用のＹ／Ｍ／Ｃ信号である。
【００６１】
入力信号のＬ^* は、白黒モード及び原稿中の黒文字を再現する信号として使用される。セレクタ４５は、制御部６から入力される印字色サイクルを示す信号（Ｃｙｃｌｅ信号）を受け、Ｋ色を印字する時にＬ^* 信号を出力し、それ以外のＹ、Ｍ、Ｃ色を印字する時には「０」を出力することによって画素値をリセットする。
【００６２】
セレクタ４４は、後述する色空間変換切換信号（ＣＣ−Ｔａｇ信号）にしたがって、色補正部４１、色補正部４２、色補正部４３より出力されるＹ／Ｍ／Ｃ／Ｋ信号、及び、セレクタ４５から入力されるＬ^* 信号または「０」の４つの信号から、いずれか１つを画素毎に選択して出力する。図９は、ＣＣ−Ｔａｇ信号の一例の説明図である。ＣＣ−Ｔａｇ信号は、例えば２ビット／画素の信号であり、それぞれのビット値の組み合わせによって、色補正部４１〜４３の出力あるいはＬ^* 信号または「０」のいずれを選択するかを示している。
【００６３】
図１０は、色補正部４１〜４３の一例を示す概略構成図、図１１は、色補正部４１〜４３における色空間の分割方法の一例を示す説明図である。図中、５１は基準データ用色補正メモリ、５２は補間用領域選択信号メモリ、５３〜５５は補間用信号出力メモリ、５６〜５８は補間用乗算器、５９は加算部である。ここでは一例として色補正部４１について示しているが、色補正部４２、色補正部４３についても同様の構成である。
【００６４】
色補正部４１〜４３は、上述のようにＬ^* ａ^* ｂ^* 信号よりＹ／Ｍ／Ｃ／Ｋ信号を生成するものであり、例えば特開平５−１１０８４０号公報に記載されている方式等を用いて実現することができる。この例における色補正部４１〜４３は、予め設定されたテーブルメモリを用いてＬ^* ａ^* ｂ^* からＹ／Ｍ／Ｃ／（Ｋ）を生成するものである。入力されたＬ^* ａ^* ｂ^* 信号をそれぞれ上位４ビットと下位４ビットに分け、上位ビットをアドレスとして色補正メモリを用いて、基準データを算出し、下位４ビットを用いて補間回路によりその間を補間することによって色補正を実施することができる。
【００６５】
図１１に示すように、色補正部４１〜４３では、３次元のＬ^* ａ^* ｂ^* 色空間をＬ^* ，ａ^* ，ｂ^* それぞれの上位４ビットにより決定される立方体に分割する。そして、その頂点座標に対応するＹ／Ｍ／Ｃ（／Ｋ）出力値を基準データとして記憶しておく。
【００６６】
分割された立方体は、補間演算のために、図１１に示すようにさらに６つの四面体に分割される。入力されるＬ^* ，ａ^* ，ｂ^* の値は、その上位４ビット及び下位４ビットにより規定される座標値から、どの四面体に属するかが判定される。そして属する四面体の４頂点に対応するＹ／Ｍ／Ｃ（／Ｋ）値を用いた補間演算が行われる。
【００６７】
図１０において、基準データ用色補正メモリ５１はＬ^* ａ^* ｂ^* 信号の上位４ビットの組をアドレス信号として、基準データを出力する色補正メモリである。補間用領域選択信号メモリ５２は、下位４ビットの組をアドレス信号として、入力されたＬ^* ，ａ^* ，ｂ^* の値が、図１１に示す６つの四面体のいずれに属するかを判定するものである。補間用信号出力メモリ５３、５４、５５は、上位４ビットの組及び補間用領域選択信号メモリ５２の出力を受けて、補間演算用の信号を出力する。補間用乗算器５６、５７、５８は、入力信号の下位４ビットと補間用信号出力メモリ５３、５４、５５から出力される補間演算用の信号（補間係数）を乗算する。加算部５９は、基準データ用補正メモリ５１および補間用乗算器５６、５７、５８の出力信号を加算する。
【００６８】
また、基準データ用色補正メモリ５１及び補間用信号出力メモリ５３、５４、５５には、画像出力２における印字色の切り替わりを示すＣｙｃｌｅ信号が入力されている。このＣｙｃｌｅ信号に従って、Ｙ色印字時にはＹ信号生成用の補正データを出力し、同様にＭ色／Ｃ色／Ｋ色印字時にはＭ信号／Ｃ信号／Ｋ信号生成用の補正データをそれぞれ出力する。色補正部４１、色補正部４２、色補正部４３では、以上のような動作によりＬ^* ａ^* ｂ^* 信号からＹ／Ｍ／Ｃ（／Ｋ）信号を生成している。
【００６９】
図１２は、空間補正部３２の一例を示す概略構成図、図１３は、空間補正部３２で行われる畳み込み演算処理の一例の説明図である。図中、６１はラインバッファ、６２〜６７は補正演算部、６８はセレクタである。ラインバッファ６１は、後述の空間補正演算に必要とされる７ライン分の画像データを確保すべく、６ラインのデータ遅延を行う。補正演算部６２〜６７は、例えば畳み込み演算などによって空間補正演算を行う。例えば図１３に示すように、注目画素（ｉ，ｊ）とすると、その周辺の（ｉ−４，ｊ−３）〜（ｉ＋４，ｊ＋３）の７×９（副走査方向×主走査方向）＝６３画素に対して、所定演算係数φ１１〜φ７９を用いた畳み込み演算により空間補正処理を実現することができる。ここで、演算係数φ１１〜φ７９は、総和が１．０となる空間補正係数である。補正演算部６２〜６７には、Ｙ／Ｍ／Ｃ／Ｋ各色に対する補正係数が予め設定されており、制御部６からのＣｙｃｌｅ信号にあわせて印字色の補正係数を用いた畳み込み演算が実施される。
【００７０】
図１２に示すように、空間補正部３２は６個の補正演算部６２〜６７を有し、Ｔａｇ信号生成部３５においてＡｒｅａ−Ｔａｇ信号及びＳｅｇ−Ｔａｇ信号から生成される３ビット／画素の空間補正切換信号（Ｆｉｌｔｅｒ−Ｔａｇ信号）に基づいて、セレクタ６８で６個の補正演算部６２〜６７の出力値を画素単位に選択して出力する。
【００７１】
図１４は、Ｆｉｌｔｅｒ−Ｔａｇ信号の値に対する補正演算部６２〜補正演算部６７の選択論理及びその処理内容の一例の説明図である。図１４に示すように、Ｆｉｌｔｅｒ−Ｔａｇ信号の値によって、補正演算部６２〜６７から出力される補正演算結果のうちの１つが選択される。補正演算部６２では、絵柄画像用の空間補正が行われる。原稿タイプとして写真タイプが指定された場合、および、原稿タイプとして文字／写真タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が絵柄を表す「００（文字以外）」（図５参照）の場合に、この補正演算部６２の演算結果が選択される。
【００７２】
補正演算部６３では、文字用の空間補正が行われる。原稿タイプとして文字／写真タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が文字を表す「０１（黒文字）、１１（色文字）」（図５参照）の場合に、この補正演算部６３の演算結果が選択される。
【００７３】
補正演算部６４では、ビジネス文書などに多用されるグラフィクスやソリッド（均一色）要素に対する空間補正が行われる。原稿タイプとして文字タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が「００（文字以外）」（図５参照）の場合に、この補正演算部６４の演算結果が選択される。
【００７４】
補正演算部６５では、補正演算部６３の補正よりもさらに強調の度合いが強い文字用の空間補正が行われる。原稿タイプとして文字タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が文字を表す「Ｏ１（黒文字）、１１（色文字）」（図５参照）の場合に、この補正演算部６５の演算結果が選択される。
【００７５】
補正演算部６６では、地図用の空間補正が行われる。原稿タイプとして地図タイプが指定された場合に、この補正演算部６６の演算結果が選択される。
【００７６】
補正演算部６７では、文字や線画等が主体の白黒原稿用の空間補正が行われる。カラーモードが白黒で且つ原稿タイプとして文字タイプが指定された場合に、この補正演算部６７の演算結果が選択される。空間補正は以上のような構成および動作によって実施される。
【００７７】
図１５は、階調補正部の一例を示す概略構成図である。図中、７１〜８０は補正ＬＵＴ、８１はセレクタである。補正ＬＵＴ７１〜８０は、それぞれ階調補正処理を行う。例えば、１次元のテーブルを参照する公知のＬＵＴ（ルックアップテーブル）で実現することができる。補正ＬＵＴ７１〜８０にはＹ／Ｍ／Ｃ／Ｋ各色に対する出力値が予め設定されており、制御部６からのＣｙｃｌｅ信号および入力画素値により、ＬＵＴの所定アドレスを参照して出力値を求める。
【００７８】
図１５に示すように、階調補正部３３は補正ＬＵＴ７１〜補正ＬＵＴ８０とセレクタ８１を有している。Ｔａｇ信号発生部３５においてＡｒｅａ−Ｔａｇ信号及びＳｅｇ−Ｔａｇ信号から生成される４ビット／画素の階調補正切り替え信号（ＴＲＣ−Ｔａｇ信号）に基づいて、セレクタ８１で１０個の補正演算部７１〜８０の出力値を画素単位に選択し、出力する。
【００７９】
図１６は、ＴＲＣ−Ｔａｇ信号の値に対する補正ＬＵＴ７１〜８０の選択論理及びその処理内容の一例の説明図である。図１６に示すように、ＴＲＣ−Ｔａｇ信号の値に従って補正ＬＵＴ７１〜８０の出力信号のうちの１つがセレクタ８１で選択されて出力される。ここで、補正ＬＵＴ７１〜補正ＬＵＴ７５は、カラー原稿の階調補正用のＬＵＴであり、カラーモードが「４色（００）、３色（０１）」（図６参照）の場合に使用される。また、補正ＬＵＴ７６〜補正ＬＵＴ８０は、白黒原稿又はカラー原稿の白黒再現用の補正ＬＵＴであり、カラーモードが「白黒（１０）」（図６参照）の時に使用される。
【００８０】
補正ＬＵＴ７１では、絵柄画像用の階調補正が行われる。原稿タイプとして写真タイプが指定された場合、および、原稿タイプとして文字／写真タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が絵柄を表す「００（文字以外）」（図５参照）の場合に、この補正ＬＵＴ７１の出力値が選択される。
【００８１】
補正ＬＵＴ７２では、文字用の階調補正が行われる。原稿タイプとして文字／写真タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が文字を表す「０１（黒文字）、１１（色文字）」（図５参照）の場合に、この補正ＬＵＴ７２の出力値が選択される。
【００８２】
補正ＬＵＴ７３および補正ＬＵＴ７４では、文字や線画の多いビジネス文書などの原稿を対象とする階調補正が行われ、補正ＬＵＴ７１及び補正ＬＵＴ７２に比べてコントラストが高めな階調補正が設定される。補正ＬＵＴ７３では、ビジネス文書などに多用されるグラフィクスやソリッド（均一色）要素に対する階調補正が行われる。原稿タイプとして文字タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が「００（文字以外）」（図５参照）の場合に、この補正ＬＵＴ７３の出力値が選択される。また補正ＬＵＴ７４は、文字用の階調補正ＬＵＴである。原稿タイプとして文字タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が文字を表す「０１（黒文字）、１１（色文字）」（図５参照）の場合に、この補正ＬＵＴ７４の演算結果が選択される。
【００８３】
補正ＬＵＴ７５は、地図に代表されるような、高精細な原稿の階調補正を対象とするＬＵＴである。原稿タイプとして地図タイプが指定された場合に、この補正ＬＵＴ７５の出力値が選択される。
【００８４】
白黒モードが選択された場合も、上述のカラー再現の場合と同様の論理で階調補正が設定される。補正ＬＵＴ７６では、絵柄画像用の階調補正が行われる。原稿タイプとして写真タイプが指定された場合、および、原稿タイプとして文字／写真タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が絵柄を表す「０１（文字以外）」（図５参照）の場合に、この補正ＬＵＴ７６の出力値が選択される。
【００８５】
補正ＬＵＴ７７では、文字用の階調補正が行われる。原稿タイプとして文字／写真タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が絵柄を表す「０１（黒文字）、１１（色文字）」（図５参照）の場合に、この補正ＬＵＴ７７の出力値が選択される。
【００８６】
補正ＬＵＴ７８および補正ＬＵＴ７９では、文字や線画の多いビジネス文書などの原稿を対象とする階調補正が行われる。補正ＬＵＴ７６及び補正ＬＵＴ７７に比べてコントラストが高めな階調補正が設定される。補正ＬＵＴ７８ではビジネス文書などに多用されるグラフィクスやソリッド（均一色）要素に対する階調補正が行われる。原稿タイプとして文字タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が「００（文字以外）」（図５参照）の場合に、この補正ＬＵＴ７８の出力値が選択される。
【００８７】
補正ＬＵＴ７９は、文字用の階調補正ＬＵＴである。原稿タイプとして文字タイプが指定されて且つ絵／文字分離部１３での識別結果であるＳｅｇ−Ｔａｇ信号の値が文字を表す「０１（黒文字）、１１（色文字）」（図５参照）の場合に、この補正ＬＵＴ７９の演算結果が選択される。
【００８８】
補正ＬＵＴ８０は、地図に代表されるような、高精細な原稿の階調補正を対象とするＬＵＴである。原稿タイプとして地図タイプが指定された場合にこの補正ＬＵＴ８０の出力値が選択される。以上のような構成及び動作によって、階調補正は実施される。
【００８９】
図１７は、中間調生成部３４の一例を示す概略構成図である。図中、９１は画素値演算部、９２は演算係数＆パターン記憶部、９３は波形パターン記憶部、９４は比較部、９５は参照波生成部である。図１７に示す中間調生成部３４は、例えば特開平９−１２１２８３号公報において提案されるような、１画素あたり８ビットのＹ／Ｍ／Ｃ／Ｋ信号から画像出力部２のＬＤ（レーザーダイオード）をＯＮ／ＯＦＦ制御する２値信号を生成するものである。
【００９０】
画素値演算部９１は、後述する演算によってＹ／Ｍ／Ｃ／Ｋ信号から所望のスクリーンを生成するための画素値を演算する。演算係数＆パターン部９２は、画素値演算部９１で必要とされるパターンマトリクス及び演算係数を記憶しており、入力される中間調生成切換信号（Ｓｃｒｅｅｎ−Ｔａｇ信号）および制御部６からのＣｙｃｌｅ信号に従って所定の係数及びパターンを画素値演算部９１へ送出する。図１８は、演算パターンマトリクスの一例の説明図である。図１８に示すように、演算パターンマトリクスは公知のディザ処理において用いられる閾値マトリクスと同様なデータとすることができ、演算係数はそのパターンマトリクスにおける閾値のステップ数を示す数値である。図１８では、演算係数が１６個の場合と１７個の場合を示している。
【００９１】
波形パターン記憶部９３は、演算係数＆パターン記憶部９２に記憶されている演算パターン及び演算係数に対応する波形パターンを記憶している。図１９は、波形パターンの一例の説明図である。図１９（Ａ），（Ｂ）は、それぞれ図１８（Ａ），（Ｂ）に対応する波形パターンである。なお、波形パターンＡ，Ｂ，Ｃについては後述する。この波形パターン記憶部９３も演算係数＆パターン記憶部９２と同様に、入力されるＳｃｒｅｅｎ−Ｔａｇ信号および制御部６からのＣｙｃｌｅ信号に従って、画素あたり２ビットの波形パターン選択用の信号を参照波生成部９５へ送出する。
【００９２】
参照波生成部９５は、波形パターン記憶部９３に記憶されている波形パターンを示す信号に従って、参照波Ａ、参照波Ｂ、および参照波Ｃのいずれかの三角波を生成し、比較部９４へ送出する。図２０は、参照波および出力信号の生成過程の説明図である。この参照波生成部９５では、図２０（Ａ）に示す３種類の参照波、すなわち、次第に増加する参照波Ａ、次第に減少する参照波Ｂ、三角波形の参照波Ｃのうちのいずれかを生成して比較部９４に出力する。
【００９３】
比較部９４は、画素値演算部９１が出力してくる８ビット／画素のデジタル画像信号をアナログ信号に変換した後、参照波生成部９５から入力されてくる参照波と比較を行って、ＬＤを制御する２値信号を出力する。図２０（Ｂ）において、比較部９４では画素値演算部９１から出力された信号のＤ／Ａ変換後の信号として、階段状の信号を示している。この信号と、参照波生成部９５で生成される参照波Ａ、参照波Ｂ、参照波Ｃとを比較し、参照波の方が小さい場合にＯＮ、大きい場合にＯＦＦの信号を２値信号として出力する。これによって、図２０（Ｂ）のＬＤ点灯波形として示した２値信号が出力される。この２値信号に従ってＬＤを点灯制御することによって、図２０（Ｂ）に出力画像として示すように、画素値演算部９１から出力される画像信号に応じて幅が変化する出力画像が形成される。なお、参照波Ａを用いた場合には記録される部分が左に寄り、参照波Ｂを用いた場合には右に寄り、参照波Ｃを用いた場合には中央に寄せて記録される。このようにして中間調生成部３４では、このような波形パターンの制御によって、高精度な印字位置制御を実現している。
【００９４】
図２１は、画素値演算部９１の一例を示すブロック図である。図中、１０１は減算器、１０２は乗算器、１０３，１０４は比較器、１０５はセレクタである。Ｙ／Ｍ／Ｃ／Ｋの入力信号は減算器１０１に入力される。減算器１０１のもう一方には、演算係数＆パターン記憶部９２より入力信号に同期してそのマトリクスサイズに基づいて所定間隔で送出されてくる演算パターンが示す値が入力され、この値が入力信号から減じられる。次に、乗算器１０２で前記入力信号と演算パターンとの差分値に対して演算係数＆パターン記憶部９２より送出される演算係数を乗算する処理が行われる。そして、比較器１０３、１０４及びセレクタ１０５に入力され、比較器１０３では２５５を上回る値を持つ画素についてはセレクタ１０５で「２５５」が選択されるように制御し、比較器１０４では０を下回る値を有する画素についてはセレクタ１０５で「０」が選択されるように制御する。
【００９５】
以上のような構成によって、中間調生成部３４は、画素単位に演算係数や参照波を切り換えて、複数種類の線数及び角度を有する網点画像を形成することが可能になる。
【００９６】
図２２は、Ｓｃｒｅｅｎ−Ｔａｇ信号と対応する線数およびその処理内容の一例の説明図である。なお、以下の説明においてカラーモードおよび原稿タイプの値については図６を、Ｓｅｇ−Ｔａｇ信号については図５を参照されたい。図２２に示すように、Ｓｃｒｅｅｎ−Ｔａｇ信号が「００」の場合には、階調性に優れる１５０線のドットスクリーンが形成され、これは原稿タイプが「１０（写真）」の時に選択される。
【００９７】
またＳｃｒｅｅｎ−Ｔａｇ信号が「０１」の場合には、階調性に優れ、且つモアレの生じにくい２００線のラインスクリーンが形成され、原稿タイプが「００（文字／写真）」で且つ絵／文字分離部１３での識別結果（Ｓｅｇ−Ｔａｇ信号）が「００（文字以外）」の場合と、カラーモードが「００（４色）及び０１（３色）」で原稿タイプが「０１（文字）」で且つ絵／文字分離部１３での識別結果（Ｓｅｇ−Ｔａｇ信号）が「００（文字以外）」の場合の画素に対して生成される。
【００９８】
続いてｓｃｒｅｅｎ−Ｔａｇ信号が「１０」の場合には、細かな文字や線画要素の情報も欠落しない３００線のラインスクリーンが形成され、これは原稿タイプが「１１（地図）」の場合に選択される。
【００９９】
最後にＳｃｒｅｅｎ−Ｔａｇが「１１」の場合には、６００線のラインスクリーンが形成され、これは原稿タイプが「００（文字／写真）」で且つ絵／文字分離部１３での識別結果（Ｓｅｇ−Ｔａｇ信号）が「０１もしくは１１（文字）」の場合とカラーモードが「１０（白黒）」で原稿タイプが「０１（文字）の場合の画素に対して生成される。
【０１００】
図２３、図２４は、Ｔａｇ信号生成部３５において生成するＴａｇ信号の一例の説明図である。Ｔａｇ信号生成部３５は、蓄積部５に一旦蓄積され、後段画像処理部４に入力されてくる２つのＴａｇ信号、すなわちＡｒｅａ−Ｔａｇ信号及びＳｅｇ−Ｔａｇ信号から、色空間変換部３１、空間補正部３２、階調補正部３３、及び中間調生成部３４での処理に必要とされる画素単位の処理切換信号、各種Ｔａｇ信号を生成する。ここでＴａｇ信号生成部３５は、Ａｒｅａ−Ｔａｇ信号４ビット及びＳｅｇ−Ｔａｇ信号２ビットの合計６ビットで示される６４通りの組み合わせに応じて、色空間変換部３１で使用する２ビットのＣＣ−Ｔａｇ信号、空間補正部３２で使用する３ビットのＦｉｌｔｅｒ−Ｔａｇ信号、階調補正部３３で使用する４ビットのＴＲＣ−Ｔａｇ信号、及び中間調生成部３４で使用する２ビットのＳｃｒｅｅｎ−Ｔａｇ信号をそれぞれ出力する。このＴａｇ信号生成部３５は、例えば、予め定められたＴａｇ信号生成論理をテーブル参照することにより実現される。図２３及び図２４は、そのＴａｇ信号生成論理を示した表である。このＴａｇ信号生成論理に従って、入力されたＡｒｅａ−Ｔａｇ信号及びＳｅｇ−Ｔａｇ信号から、ＣＣ−Ｔａｇ信号、Ｆｉｌｔｅｒ−Ｔａｇ信号、ＴＲＣ−Ｔａｇ信号、Ｓｃｒｅｅｎ−Ｔａｇ信号をそれぞれ生成して出力する。
【０１０１】
図２５は、蓄積部５の一例を示す概略構成図である。図中、１１１〜１１３は符号化部、１１４〜１１６は復号化部、１１７はデータ蓄積部、１１８はメモリコントローラ、１１９はバッファメモリ、１２０はバスである。蓄積部５は、画像入力部１の原稿走査動作と同期して入力されてくるＬ^* 、ａ^* 、ｂ^* の３信号を蓄積保持し、画像出力部２の印字色数の回数だけの印字動作に同期して、蓄積保持しているＬ^* 、ａ^* 、ｂ^* の信号を出力する。また、図示しない操作部より指定される、例えばスタック、丁合などのソート機能や、例えば回転、Ｎｕｐ、シグネチャ、両面印字などのページ編集機能も、この蓄積部５によって実現される。さらに、前段画像処理部３から出力されるＡｒｅａ−Ｔａｇ信号、Ｓｅｇ−Ｔａｇ信号も入力される画像データと対応付けて蓄積し、また、対応する画像データが読み出されるときにこれらの信号を出力する。
【０１０２】
蓄積部５に入力されてくる８ビット／画素のＬ^* ａ^* ｂ^* 信号は、符号化部１１３へ入力される。符号化部１１３では、例えばＪＰＥＧなどに代表される所定の画像圧縮方式でページ単位に、また各ページにおいてＬ^* 、ａ^* 、ｂ^* の面単位に画像信号を符号化し、バス１２０を経由してデータ蓄積部１１７へ画像データを出力する。この符号化部１１３が第１の符号化手段に対応する。
【０１０３】
また、Ｌ^* ａ^* ｂ^* 信号に同期して入力される４ビット／画素のＡｒｅａ−Ｔａｇ信号は符号化部１１１へ入力され、例えばランレングス符号化などの公知の可逆圧縮方式で符号化されて、バス１２０を経由してデータ蓄積部１１７に保存される。同様にＬ^* ａ^* ｂ^* 信号に同期して入力される２ビット／画素のＳｅｇ−Ｔａｇ信号は符号化部１１２へ入力され、例えばランレングス符号化などの公知の可逆圧縮方式で符号化されて、バス１２０を経由してデータ蓄積部１１７に保存される。この符号化部１１１および符号化部１１２が第２の符号化手段に対応する。
【０１０４】
データ蓄積部１１７は、符号化部１１１、符号化部１１２、符号化部１１３で符号化されたＬ^* ａ^* ｂ^* の入力画像データ、Ａｒｅａ−Ｔａｇ信号、Ｓｅｇ−Ｔａｇ信号をページ単位に記憶する。このデータ蓄積部１１７は、符号化された画像データ及びＴａｇ信号データを複数ページに渡って記憶する事が可能な大容量の記憶装置、例えばハードディスク装置などにより実現することができる。なお、このデータ蓄積部１１７は、画像データ蓄積手段、および属性データ蓄積手段の両方に対応するものである。
【０１０５】
復号化部１１６は、データ蓄積部１１７にページ単位に蓄積されている画像データを読み出し、画像出力部２の印字動作に同期して所定の伸長方式によりＬ^* ａ^* ｂ^* 信号を復号し、後段画像処理部４へ出力する。この復号化部１１６は、第１の復号手段に対応するものである。
【０１０６】
同様に復号化部１１４は、データ蓄積部１１７にページ単位に蓄積されているＡｒｅａ−Ｔａｇデータを読み出し、画像出力部２の印字動作に同期して所定の伸長方式によりＡｒｅａ−Ｔａｇ信号を復号し、後段画像処理部４へ出力する。復号化部１１５は、データ蓄積部１１７にページ単位に蓄積されているＳｅｇ−Ｔａｇデータを読み出し、画像出力部２の印字動作に同期して所定の伸長方式によりＳｅｇ−Ｔａｇ信号を復号し、後段画像処理部４へ出力する。これらの復号化部１１４および復号化部１１５は、第２の復号手段に対応するものである。
【０１０７】
バッファメモリ１１９およびメモリコントローラ１１８は、回転処理やＮｕｐ合成、シグネチャなどのページ編集を行う際に使用される編集手段である。
【０１０８】
なお、図２５において、符号化部１１１、符号化部１１２、符号化部１１３、復号化部１１４、復号化部１１５、復号化部１１６、データ蓄積部１１７、メモリコントローラ１１８は、バス１２０で結ばれている。
【０１０９】
以下、蓄積部５で実施されるソート機能及びページ編集機能について説明を行う。図２６は、蓄積部５で実現されるソート機能の一例の説明図である。ここでは図２６（Ａ）に示すような４枚の原稿を４部コピーする場合について説明する。図２６（Ｂ）は丁合モードでのコピー結果であり、図２６（Ｃ）はスタックモードでのコピー結果である。
【０１１０】
この実施の形態では、画像入力部１において読み込まれた原稿画像は、前段画像処理部３での各種処理を受け、Ｌ^* ａ^* ｂ^* 信号に変換される。そしてＬ^* ａ^* ｂ^* 信号は、絵／文字分離部１３で生成されるＳｅｇ−Ｔａｇ信号および制御部から送出されてくるＡｒｅａ−Ｔａｇ信号とともに、蓄積部５へ入力される。蓄積部５で、それぞれ対応する符号化部で圧縮された後、データ蓄積部１１７にページ単位に蓄積される。
【０１１１】
図２６（Ｂ）に示すような丁合モードコピーの場合には、全ての原稿の読み取り動作がまず行われる。すなわち４ページの原稿（「Ａ」、「Ｂ」、「Ｃ」、 「Ｄ」）の画像信号データ及びＴａｇ信号データがデータ蓄積部１１７へ蓄積される。その後、画像出力部２での印字動作に合わせて、画像信号データ及びＴａｇ信号データを所定の方式で復号化し、後段画像処理部４へ出力する。ここで、データ蓄積部１１７から１ページ目（Ａ）→２ページ目（Ｂ）→３ページ目（Ｃ）→４ページ目（Ｄ）の順番で画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データを読み出しそれぞれ復号化部１１６、復号化部１１４及び復号化部１１５で復号化処理を行う。その後、画像出力部２の印字動作に同期して、Ｌ^* ａ^* ｂ^* 画像信号、Ａｒｅａ−Ｔａｇ信号及びＳｅｇ−Ｔａｇ信号を後段画像処理部４へ出力する。
【０１１２】
図２６（Ｃ）に示すようなスタックモードコピーの場合には、１枚目の原稿（「Ａ」）を入力部１０１で読み込み、画像信号データ及びＴａｇ信号データをデータ蓄積部１１７へ蓄積し終えると、２枚目以降の原稿（「Ｂ」、「Ｃ」、「Ｄ」）も同様に読み込み及び蓄積を行うとともに、画像出力部２での印字動作に合わせて、１枚目の原稿（「Ａ」）の画像信号データ及びＴａｇ信号データを所定の方式で復号化し、後段画像処理部４へ出力する。この１枚目の原稿（「Ａ」）の画像信号データ及びＴａｇ信号データの復号化および出力を所定部数（ここでは４部）の回数だけ繰り返し行う。１枚目の原稿を所定部数だけ印字完了した後、２枚目の原稿（「Ｂ」）のデータ蓄積部１１７への画像信号データ及びＴａｇ信号データの蓄積が完了していれば、続いて１枚目の場合と同様に２枚目の印字を所定部数だけ行う。以上のような動作を３枚目の原稿（Ｃ）及び４枚目の原稿（Ｄ）に対しても実行することによりスタックモードコピーが可能となる。
【０１１３】
図２７は、ページ編集機能の一つである回転処理の一例の説明図である。図中、ＦＳ方向及びＳＳ方向とは主走査方向及び副走査方向をそれぞれ示す。以下の説明においても同様である。図２７（Ａ）は、原稿画像の向きがバラバラな状態で画像入力部１の図示しない原稿載置台上に置かれ、画像の読み込みが行われた場合を示す。このような場合には、図２７（Ｂ）に示すように、画像を回転させることによって出力コピーの向きを揃える動作が行われる。この時、長辺を主走査方向として副走査方向の長さを短くするように回転処理を行うことにより、画像印字の生産性を向上させることが可能となる。図２７に示す例では、画像「Ａ」、画像「Ｄ」と画像「Ｂ」、画像「Ｃ」の向きが異なっている。この場合、主走査方向に長辺を有する画像「Ｂ」、画像「Ｃ」の向きに一致するように、画像「Ａ」、画像「Ｄ」を回転させることによって、コピーの向きをそろえることができる。
【０１１４】
図２８は、拡大、縮小処理を伴う回転処理の一例の説明図である。図２８に示す例では、例えばＡ３とＡ４など、サイズの異なる原稿を同じ大きさの用紙へコピーする場合の読み取り及び蓄積を示している。図２８（Ａ）では、例えば２枚目及び３枚目（「Ｂ」及び「Ｃ」）はＡ４サイズの原稿を、１枚目及び４枚目（「Ａ」及び「Ｄ」）はＡ３サイズの原稿を示す。ここで、画像入力部１の制約から１枚目及び４枚目（「Ａ」及び「Ｄ」）は主走査方向を長辺として読み込むことができないため、前段画像処理部３の画像変倍部１４で縮小処理を施し、蓄積部５においては図２８（Ｂ）に示すように主走査方向と副走査方向の長さが異なる画像信号データが蓄積されることになる。
【０１１５】
このような場合にも、図２８（Ｃ）に示すように、縮小処理によって大きさが揃えられた画像を回転させることによって、出力コピーの向きを揃える動作が行われる。この時、長辺を主走査方向として副走査方向の長さを短くするように回転処理を行うことにより画像印字の生産性を向上させることが可能となる。
【０１１６】
画像に対して回転処理を行うか否かは、操作者が図示しない操作部から入力するコピー条件や、前段画像処理部３内の原稿検知部１６を利用して予備走査で得た原稿情報を基に、制御部６で判断して、蓄積部５での動作が制御される。
【０１１７】
蓄積部５における画像の回転処理は、バッファメモリ１１９及びメモリコントローラ１１８を用いて実現される。回転処理を行う原稿を印字する際には、画像出力部２での印字動作に先立って、画像信号データ及びそれに対応するＡｒｅａ−Ｔａｇ信号データ、Ｓｅｇ−Ｔａｇ信号データがデータ蓄積部１１７から読み出され、それぞれ復号化部１１６、復号化部１１４、復号化部１１５で復号される。その後、メモリコントローラ１１８で所定の回転処理が行われ、バッファメモリ１１９へ格納される。回転処理は、例えばバッファメモリ１１９への格納あるいは読み出し時のアドレス制御などによって行うことが可能である。
【０１１８】
バッファメモリ１１９は、Ｌ^* ａ^* ｂ^* 画像信号用の８ビット／画素のページメモリ３面と、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データ用の６ビット／画素のページメモリ１面とからなる計４面のページメモリから構成することができる。所定の回転処理が行われた後、バッファメモリ１１９で蓄積保持されたＬ^* ａ^* ｂ^* 画像信号データとＡｒｅａ−Ｔａｇ信号データ及びＳｅｇ−ＴａｇのＴａｇ信号データは、画像出力部２での印字動作に同期して読み出され、復号化部１１６、復号化部１１４、復号化部１１５での復号処理をバイパスし、後段画像処理部４ヘ送出される。
【０１１９】
また、ここで丁合モードのような場合に回転処理が発生した時には、繰り返し回転処理を行うとコピーの生産性を損なってしまう。そこで、所定の回転処理が行われた後、バッファメモリ１１９で蓄積保持されたＬ^* ａ^* ｂ^* 画像信号データとＡｒｅａ−Ｔａｇ信号データ及びＳｅｇ−ＴａｇのＴａｇ信号データを、それぞれ符号化部１１３、符号化部１１１及び符号化部１１２で再び符号化し、データ蓄積部１１７に格納しておくとよい。回転処理が必要とされる全ての原稿画像及びＴａｇ信号データに対する処理が完了し、データ蓄積部１１７への格納が完了した後は、画像出力部２での印字動作に同期して該当ページのＬ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データが読み出され、復号化部１１６、復号化部１１４、復号化部１１５で復号処理が行われた後、後段画像処理部４へ送出される。
【０１２０】
図２９は、複数ページの原稿を１枚の用紙上に配置して印字する「Ｎｕｐ機能」の一例の説明図である。図２９（Ａ）は原稿を示し、ここでは４枚の原稿「Ａ」、「Ｂ」、「Ｃ」、「Ｄ」を示している。また、図２９（Ｂ）は２ｕｐ編集、図２９（Ｃ）は４ｕｐ編集をそれぞれ示している。この実施の形態におけるＮｕｐ処理は、上述の回転処理と同様に、バッファメモリ１１９及びメモリコントローラ１１８を用いて実現することができる。
【０１２１】
図２９（Ｂ）に示すような２ｕｐ編集の場合には、まず１枚目及び２枚目（「Ａ」及び「Ｂ」）の原稿が読み込まれ、それぞれの符号化された画像信号データ及びＴａｇ信号データがデータ蓄積部１１７へ蓄積される。次に１枚目の原稿（「Ａ」）の画像信号データ及びＡｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データが読み出され、復号化部１１６、復号化部１１４及び復号化部１１５で復号化した後、図２９（Ｂ）に示すような配置となるようにメモリコントローラ１１８で制御してバッファメモリ１１９内の所定のアドレスに格納する。続いて２枚目の原稿（「Ｂ」）も同様の処理を経て、１枚目の原稿（「Ａ」）と並んで配置されるようにバッファメモリ１１９内の所定のアドレスに格納される。以上の様にバッファメモリ１１９内に保持された１枚目及び２枚目の原稿（「Ａ」及び「Ｂ」）のＬ^* ａ^* ｂ^* 画像データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データは、画像出力部２での印字動作に同期して１枚の画像及びＴａｇ信号のセットとして読み出され、復号化部１１６、復号化部１１４、復号化部１１５での復号処理をバイパスし、後段画像処理部４へ送出される。３枚目及び４枚目の原稿（「Ｃ」及び「Ｄ」）に対しても同様の処理が行われ、２枚の２ｕｐコピーを実現する。
【０１２２】
なお、上述の回転処理と同様に丁合コピー等の場合には、全てのページの２ｕｐ処理を行った後、符号化を行い、データ蓄積部１１７へ蓄積することによって、コピーの生産性を上げることが可能である。
【０１２３】
図２９（Ｃ）に示すように４ｕｐ編集の場合にも、上述の２ｕｐ編集と同様に実現できる。まず１〜４枚目全ての原稿（「Ａ」、「Ｂ」、「Ｃ」、「Ｄ」）が読み込まれ、それぞれの符号化されたＬ^* ａ^* ｂ^* 画像信号データ及びＴａｇ信号データがデータ蓄積部１１７へ蓄積される。次に１枚目の原稿（「Ａ」）のＬ^* ａ^* ｂ^* 画像データ及びＡｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データが読み出され、復号化部１１６、復号化部１１４及び復号化部１１５で復号化された後、図２９（Ｃ）に示すような方向及び配置となるように、メモリコントローラ１１８で回転処理及び書き込み制御が行われ、バッファメモリ１１９内の所定のアドレスに格納される。続いて２枚目、３枚目、４枚目の原稿（「Ｂ」、「Ｃ」、「Ｄ」）も同様の処理を経て、１枚目の原稿（「Ａ」）と同様に所定の位置に所定の向きで配置されるように、バッファメモリ１１９内に格納される。以上のようにしてバッファメモリ１１９内に保持された４枚の原稿（「Ａ」、「Ｂ」、「Ｃ」、「Ｄ」）のＬ^* ａ^* ｂ^* 画像データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データは、画像出力部２での印字動作に同期して１枚の画像及びＴａｇ信号のセットとして読み出され、復号化部１１６、復号化部１１４、復号化部１１５での復号処理をバイパスし、後段画像処理部４へ送出される。
【０１２４】
図３０は、小冊子などを作成する際に有効な編集機能の一例の説明図である。上述のような回転処理や配置制御などを組み合わせることによって、より高度なページ編集を行うことが可能である。例えば図３０に示すように、複数部数の小冊子などを作成する編集機能を実現することができる。図３０（Ａ）は８枚の原稿｛原稿の読み込みは「Ａ」、「Ｂ」、「Ｃ」、「Ｄ」、「Ｅ」、「Ｆ」、「Ｇ」、「Ｊ」の順に行われる）である。図３０（Ｂ）、（Ｃ）、（Ｄ）は、各綴じ方向によって行われるページ編集の出力結果を示している。また、図（Ｂ）、（Ｃ）、（Ｄ）においてハッチングを施したページは裏面ページであることを示し、黒丸（‘●’）の点列は、製本時に例えばステープラーや糊付けなどにより綴じるための綴じ代部分を表している。なお、両面印刷は、画像出力部２において、表面印字後に用紙を所定トレイに一旦蓄積し、その後に用紙反転を行い、裏面印字を行う。用紙反転の際には、図３０において各表面の右上と裏面の右下の折れのあるコーナーが一致するように反転が行われるものとする。
【０１２５】
図３０（Ｂ）は、２ページの原稿を順番に並べる２ｕｐコピーモードで、且つ両面印刷が指定された時の各原稿の配置を示し、原稿の１枚目及び２枚目（「Ａ」及び「Ｂ」）で構成される１ページ目の上端が綴じ代に設定されている。この場合には、蓄積部５は前述の２ｕｐと同様の処理を行うことにより、所望の出力を得ることができる。
【０１２６】
まず、１枚目から８枚目までの全ての原稿（「Ａ」、「Ｂ」、「Ｃ」、「Ｄ」、「Ｅ」、「Ｆ」、「Ｇ」、「Ｊ」）を画像入力部１で読み込み、Ｌ^* ａ^* ｂ^* 画像データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データを蓄積部５へ出力する。蓄積部５では、入力されてくる画像信号及びＴａｇ信号を符号化部１１３、符号化部１１１及び符号化部１１２でそれぞれ所定の圧縮方式で符号化した後、データ蓄積部１１７へページ単位で記憶保持する。次に、１枚目の原稿（「Ａ」）のＬ^* ａ^* ｂ^* 画像信号データ及びＡｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データが読み出され、復号化部１１６、復号化部１１４及び復号化部１１５で復号化した後、図３０（Ｂ）に示すような配置となるようにメモリコントローラ１１８で制御し、バッファメモリ１１９内の所定のアドレスに格納する。続いて２枚目の原稿（「Ｂ」）も同様の処理を経て、前記１枚目の原稿（「Ａ」）と並んで配置されるようにバッファメモリ１１９内の所定のアドレスに格納する。以上の様にバッファメモリ１１９内に保持された１枚目及び２枚目の原稿（「Ａ」及び「Ｂ」）のＬ^* ａ^* ｂ^* 画像データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データは、１ページの画像信号及びＴａｇ信号としてそれぞれ符号化部１１３、符号化部１１１及び符号化部１１２で再び符号化され、データ蓄積部１１７に格納される。
【０１２７】
以下同様の処理を３枚目及び４枚目の原稿（「Ｃ」、「Ｄ」）、５枚目及び６枚目の原稿（「Ｅ」、「Ｆ」）、７枚目及び８枚目の原稿（「Ｇ」、「Ｊ」）に対して行い、データ蓄積部１１７中に印字用の４ページのＬ^* ａ^* ｂ^* 画像データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データを保持する。全てのページ配置処理、符号化処理及びデータ蓄積部１１７への蓄積処理が完了した後、画像出力部２での印字動作に同期して、原稿「Ａ」及び原稿「Ｂ」の画像から構成される１ページ目のＬ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データが読み出され、復号化部１１６、復号化部１１４、復号化部１１５で復号処理が行われた後、後段画像処理部４へ送出される。以下、原稿「Ｃ」及び原稿「Ｄ」の画像から構成される２ページ目、原稿「Ｅ」及び原稿「Ｆ」の画像から構成される３ページ目、原稿「Ｇ」及び原稿「Ｊ」の画像から構成される４ページ目の出力を行い、その動作を設定された部数分繰り返すことにより、図３０（Ｂ）に示すようなページ編集が可能となる。
【０１２８】
図３０（Ｃ）は、図３０（Ｂ）と同じく２ｕｐコピーモードでの両面印刷であるが、綴じ代が原稿の１枚目及び２枚目（「Ａ」及び「Ｂ」）で構成される１ページ目の左端に設定されている。このため、小冊子となった時の天地・左右が正常となるように、裏面印刷用の２ｕｐ編集時に図３０（Ｃ）に示すように（表面印刷用の２ｕｐ編集時と比較して）２枚の原稿の左右関係を逆に設定し、且つ両方のページの天地が反転するように１８０度の回転処理を施す必要がある。
【０１２９】
まず、１枚目から８枚目までの全ての原稿（「Ａ」、「Ｂ」、「Ｃ」、「Ｄ」、「Ｅ」、「Ｆ」、「Ｇ」、「Ｊ」）を画像入力部１で読み込み、Ｌ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データを蓄積部５へ出力する。蓄積部５では、入力されてくる画像信号及びＴａｇ信号を符号化部１１３、符号化部１１１及び符号化部１１２でそれぞれ所定の圧縮方式で符号化した後、データ蓄積部１１７へページ単位で記憶保持する。次に、１枚目の原稿（「Ａ」）のＬ^* ａ^* ｂ^* 画像信号データ及びＡｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データが読み出され、復号化部１１６、復号化部１１４及び復号化部１１５で復号化した後、図３０（Ｂ）に示すような配置となるようにメモリコントローラ１１８で制御し、バッファメモリ１１９内の所定のアドレスに格納する。続いて２枚目の原稿（「Ｂ」）も同様の処理を経て、１枚目の原稿（「Ａ」）と並んで配置されるようにバッファメモリ１１９内の所定のアドレスに格納される。
【０１３０】
以上のようにしてバッファメモリ１１９内に保持された１枚目及び２枚目の原稿（Ａ及びＢ）のＬ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データは、１ページの画像信号及びＴａｇ信号としてそれぞれ符号化部１１３、符号化部１１１及び符号化部１１２で再び符号化され、データ蓄積部１１７に格納される。
【０１３１】
続いて３枚目の原稿（「Ｃ」）のＬ^* ａ^* ｂ^* 画像信号データ及びＡｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データが読み出され、復号化部１１６、復号化部１１４及び復号化部１１５で復号化した後、図３０（Ｃ）に示すような配置となるようにメモリコントローラ１１８で回転処理及び配置制御を行い、バッファメモリ１１９内の所定のアドレスに格納する。４枚目の原稿（「Ｄ」）も同様にメモリコントローラ１１８で回転処理及び配置制御が行われ前記３枚目の原稿（「Ｃ」）と並んで配置されるようにバッファメモリ１１９内の所定のアドレスに格納される。このようにバッファメモリ１１９内に保持された３枚目及び４枚目の原稿（「Ｃ」及び「Ｄ」）のＬ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データは、１枚目及び２枚目の原稿（「Ａ」及び「Ｂ」）と同様に、１ページの画像信号及びＴａｇ信号としてそれぞれ符号化部１１３、符号化部１１１及び符号化部１１２で再び符号化され、データ蓄積部１１７に格納される。
【０１３２】
以下、５枚目及び６枚目の原稿（「Ｅ」、「Ｆ」）に対しては１枚目及び２枚目の原稿（「Ａ」及び「Ｂ」）と同様の処理を、７枚目及び８枚目の原稿（「Ｇ」、「Ｊ」）に対して３枚目及び４枚目の原稿（「Ｃ」及び「Ｄ」）と同様の処理をそれぞれ行い、データ蓄積部１１７中に印字用の４ページのＬ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データを保持する。
【０１３３】
全てのページ配置処理、符号化処理及びデータ蓄積部１１７への蓄積処理が完了した後、画像出力部２での印字動作に同期して、原稿「Ａ」及び原稿「Ｂ」の画像から構成される１ページ目のＬ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データが読み出され、復号化部１１６、復号化部１１４、復号化部１１５で復号処理が行われた後、後段画像処理部４へ送出される。以下、原稿「Ｃ」及び原稿「Ｄ」の画像から構成される２ページ目、原稿「Ｅ」及び原稿「Ｆ」の画像から構成される３ページ目、原稿「Ｇ」、原稿「Ｊ」の画像から構成される４ページ目の出力を行い、その動作を設定された部数分繰り返すことにより、図３０（Ｃ）に示すようなページ編集が可能となる。
【０１３４】
図３０（Ｄ）は、出力画像の中央を綴じる製本の場合を示している。このようなページ編集は「シグネチャ編集」と呼ばれるものであり、原稿を読み込む順番と印字する順番が全く一致しないという点で、上述の図３０（Ｂ）、（Ｃ）に示したページ編集と大きく異なる。シグネチャ編集においても画像の読み込み動作は図３０（Ｂ）、（Ｃ）のページ編集と同様である。まず、１枚目から８枚目までの全ての原稿「Ａ」、「Ｂ」、「Ｃ」、「Ｄ」、「Ｅ」、「Ｆ」、「Ｇ」、「Ｊ」）を画像入力部１で読み込み、Ｌ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データを蓄積部５へ出力する。蓄積部５では、入力されてくる画像信号及びＴａｇ信号を符号化部１１３、符号化部１１１及び符号化部１１２でそれぞれ所定の圧縮方式で符号化した後、データ蓄積部１１７へページ単位で記憶保持する。
【０１３５】
次に、図３０（Ｄ）に示すように、１ページ目の出力を構成する８枚目の原稿（「Ｊ」）のＬ^* ａ^* ｂ^* 画像信号データ及びＡｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データが読み出され、復号化部１１６、復号化部１１４及び復号化部１１５で復号化した後、図３０（Ｄ）に示すような配置となるようにメモリコントローラ１１８で制御し、バッファメモリ１１９内の所定のアドレスに格納する。続いて１枚目の原稿（「Ａ」）も同様の処理を経て、前記８枚目の原稿（Ｊ）と並んで配置されるようにバッファメモリ１１９内の所定のアドレスに格納される。以上の様にバッファメモリ１１９内に保持された８枚目及び１枚目の原稿（「Ｊ」及び「Ａ」）のＬ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データは、１ページの画像信号及びＴａｇ信号としてそれぞれ符号化部１１３、符号化部１１１及び符号化部１１２で再び符号化され、データ蓄積部１１７に格納される。
【０１３６】
続いて７枚目の原稿（「Ｇ」）のＬ^* ａ^* ｂ^* 画像信号データ及びＡｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データが読み出され、復号化部１１６、復号化部１１４及び復号化部１１５で復号化した後、図３０（Ｄ）に示すような配置となるようにメモリコントローラ１１８で回転処理及び配置制御を行い、バッファメモリ１１９内の所定のアドレスに格納する。２枚目の原稿（「Ｂ」）も同様にメモリコントローラ１１８で回転処理及び配置制御が行われ、７枚目の原稿（「Ｇ」）と並んで配置されるようにバッファメモリ１１９内の所定のアドレスに格納される。このようにバッファメモリ１１９内に保持された７枚目及び２枚目の原稿（「Ｇ」及び「Ｂ」）のＬ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データは、８枚目及び１枚目の原稿（「Ｊ」及び「Ａ」）と同様に、１ページの画像信号及びＴａｇ信号としてそれぞれ符号化部１１３、符号化部１１１及び符号化部１１２で再び符号化され、データ蓄積部１１７に格納される。
【０１３７】
以下、６枚目及び３枚目の原稿（「Ｆ」、「Ｃ」）に対しては８枚目及び１枚目の原稿（「Ｊ」及び「Ａ」）と同様の処理を行う。また、５枚目及び４枚目の原稿（「Ｅ」、「Ｄ」）に対して７枚目及び２枚目の原稿（「Ｇ」及び「Ｂ」）と同様の処理を行う。そして、データ蓄積部１１７中に印字用の４ページのＬ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データを保持する。
【０１３８】
全てのページ配置処理、符号化処理及びデータ蓄積部１１７への蓄積処理が完了した後、画像出力部２での印字動作に同期して、原稿「Ｊ」及び原稿「Ａ」の画像から構成される１ページ目のＬ^* ａ^* ｂ^* 画像信号データ、Ａｒｅａ−Ｔａｇ信号データ及びＳｅｇ−Ｔａｇ信号データが読み出され、復号化部１１６、復号化部１１４、復号化部１１５で復号処理が行われた後、後段画像処理部４へ送出される。以下、原稿「Ｇ」及び原稿「Ｂ」の画像から構成される２ページ目、原稿「Ｆ」及び原稿「Ｃ」の画像から構成される３ページ目、原稿「Ｅ」及び原稿「Ｄ」の画像から構成される４ページ目の出力を行い、その動作を設定された部数分繰り返すことにより、図３０（Ｄ）に示すようなページ編集が可能となる。
【０１３９】
以上説明したように、蓄積部５では、Ｔａｇ信号を、操作者が原稿に対してページ単位に設定する情報と、前段画像処理部３での画像識別結果とに分離して保持、蓄積する。そして、画像出力時に画像出力部２の印字色及び印字動作に合わせて、後段画像処理部４内で各処理部に必要とされる情報を生成する。これによって、蓄積部５で蓄積する情報量を削減することが可能になる。また、操作者が操作用パネルや編集用ディジタイザから入力する位置情報の精度は、通常０．２５ｍｍ（１００ｄｐｉ）程度であるので、このように論理的に情報を分離して圧縮処理を行うことによって、符号化部１１１での符号化効率も大幅に向上する。
【０１４０】
このように、上述の実施の一形態に示すようなデジタルカラー複写機の構成により、例えば極めて高い画質が要求される場合においても、例えば電子的なソート機能やページレイアウト編集などの、多彩かつ高度な編集機能実現することが可能となる。
【０１４１】
なお、本実施例では、説明のため、カラーモードや原稿タイプ、絵／文字分離部における識別類型を始め、各処理部の処理順序やその処理の切り換え、および組み合わせ論理の詳細を記述したが、本発明はこれに限定されるものではないことは言うまでもない。
【０１４２】
図３１は、本発明の画像処理装置の別の実施の形態を示すブロック構成図、図３２は、同じく前段画像処理部の一例を示す概略構成図、図３３は、同じく後段画像処理部の一例を示す概略構成図、図３４は、同じく蓄積部の一例を示す概略構成図である。図中、図１，図２，図７，図２５と同様の部分には同じ符号を付して説明を省略する。７は画像出力部、１２１は画像信号変倍部、１２２はＴａｇ信号変倍部である。
【０１４３】
この実施の形態では、蓄積部５がバス１２０上に画像信号変倍部１２１、Ｔａｇ信号変倍部１２２を持つ構成を示している。画像信号変倍部１２１は、画像信号データに対して２次元の拡大、縮小処理を行う。拡大、縮小処理の方法は任意であり、公知の手法を用いることができる。また、Ｔａｇ信号変倍部１２２は、画像信号変倍部１２１における拡大、縮小処理と同じ変倍率で、Ｔａｇ信号に対して拡大、縮小処理を行う。この場合の手法も任意である。なお、蓄積部５に画像信号変倍部１２１、Ｔａｇ信号変倍部１２２を設けているので、図３２に示すように前段画像処理部３には画像変倍部１４およびＴａｇ変倍部１５を設けていない。この例の場合も、図３４に示す画像信号変倍部１２１、Ｔａｇ信号変倍部１２２は画像前処理手段、属性前処理手段を構成する。
【０１４４】
このような構成にすることによって、画像入力部１での画像入力は常に等倍で実施することが可能になる。また、制御部６及び前段画像処理部３内の原稿検知部１６での原稿情報抽出結果に基づいて、画像信号変倍部１２１、Ｔａｇ信号変倍部１２２で縮小、拡大処理を行うので、予備走査が不要になる。
【０１４５】
また、この実施の形態では、画像出力部７はＹＭＣＫ４色の露光・現像・転写の電子写真プロセスを持っており、一時にフルカラー画像を印字することが可能である。従って、蓄積部５から後段画像処理部４へのＬ^* ａ^* ｂ^* 画像信号データ及びＴａｇ信号の出力は１回のみとなる。
【０１４６】
以上のように、画像入力及び画像出力の基本的な動作が変わっても、上述の実施の一形態における構成及び動作と本質的に変わること無く、画像処理動作を行うことが可能である。
【０１４７】
なお、上述の各実施の形態においては、画像入力部１からＲＧＢの信号を受け取り、画像出力部２や画像出力部７に対してＹＭＣＫの信号を送出した。しかし本発明はこれに限られるものではなく、例えば入力側がＬ^* ａ^* ｂ^* やＹＭＣＫ、その他種々の色空間であってよい。また、出力側も画像出力部２が受け取る画像データの色空間に応じた信号を出力すればよい。なお、画像出力部２は、上述の例のようにトナーを用いた電子写真方式に限られるものではなく、例えばインクジェット方式や感熱方式、熱転写方式など、種々の記録方式を用いることが可能である。
【０１４８】
また、上述の各実施の形態では、画像入力部１から画像が送出され、画像出力部２に対して処理後の画像を出力する構成を示したが、本発明はこれに限らず、例えばホストコンピュータに直接あるいはネットワークなどを介して接続されるプリンタとして構成することも可能である。さらには、出力する先が画像出力部２ではなく、例えばホストコンピュータであるなど、種々の形態で構成することが可能である。なお、このような場合には、前段画像処理部３、後段画像処理部４、蓄積部５で行われる各種の画像処理は、上述の機能に限られるものではなく、適宜取捨選択してもよいし、また他の機能を付加してももちろんよい。
【０１４９】
【発明の効果】
以上の説明から明らかなように、本発明によれば、例えばカラー複写機のような極めて高い画質が要求される画像処理システムにおいても、例えば電子的なソート機能やページレイアウト編集などの、多彩かつ高度な編集機能実現することが可能となるという効果がある。
【図面の簡単な説明】
【図１】 本発明の画像処理装置の実施の一形態を示すブロック構成図である。
【図２】 前段画像処理部３の一例を示すブロック構成図である。
【図３】 階調補正部１１における階調補正処理の一例を示すグラフである。
【図４】 絵／文字分離部の一例を示すブロック構成図である。
【図５】 Ｓｅｇ−Ｔａｇ信号の一例の説明図である。
【図６】 Ａｒｅａ−Ｔａｇ信号の一例の説明図である。
【図７】 後段画像処理部４の一例を示すブロック構成図である。
【図８】 色空間変換部３１の一例を示す概略構成図である。
【図９】 ＣＣ−Ｔａｇ信号の一例の説明図である。
【図１０】 色補正部４１〜４３の一例を示す概略構成図である。
【図１１】 色補正部４１〜４３における色空間の分割方法の一例を示す説明図である。
【図１２】 空間補正部３２の一例を示す概略構成図である。
【図１３】 空間補正部３２で行われる畳み込み演算処理の一例の説明図である。
【図１４】 Ｆｉｌｔｅｒ−Ｔａｇ信号の値に対する補正演算部６２〜補正演算部６７の選択論理及びその処理内容の一例の説明図である。
【図１５】 階調補正部の一例を示す概略構成図である。
【図１６】 ＴＲＣ−Ｔａｇ信号の値に対する補正ＬＵＴ７１〜８０の選択論理及びその処理内容の一例の説明図である。
【図１７】 中間調生成部３４の一例を示す概略構成図である。
【図１８】 演算パターンマトリクスの一例の説明図である。
【図１９】 波形パターンの一例の説明図である。
【図２０】 参照波および出力信号の生成過程の説明図である。
【図２１】 画素値演算部９１の一例を示すブロック図である。
【図２２】 Ｓｃｒｅｅｎ−Ｔａｇ信号と対応する線数およびその処理内容の一例の説明図である。
【図２３】 Ｔａｇ信号生成部３５において生成するＴａｇ信号の一例の説明図である。
【図２４】 Ｔａｇ信号生成部３５において生成するＴａｇ信号の一例の説明図（続き）である。
【図２５】 蓄積部５の一例を示す概略構成図である。
【図２６】 蓄積部５で実現されるソート機能の一例の説明図である。
【図２７】 ページ編集機能の一つである回転処理の一例の説明図である。
【図２８】 拡大、縮小処理を伴う回転処理の一例の説明図である。
【図２９】 複数ページの原稿を１枚の用紙上に配置して印字する「Ｎｕｐ機能」の一例の説明図である。
【図３０】 小冊子などを作成する際に有効な編集機能の一例の説明図である。
【図３１】 本発明の画像処理装置の別の実施の形態を示すブロック構成図である。
【図３２】 本発明の画像処理装置の別の実施の形態における前段画像処理部の一例を示す概略構成図である。
【図３３】 本発明の画像処理装置の別の実施の形態における後段画像処理部の一例を示す概略構成図である。
【図３４】 本発明の画像処理装置の別の実施の形態における蓄積部の一例を示す概略構成図である。
【図３５】 従来の画像複写システムの一例を示すブロック図である。
【図３６】 従来のデジタルカラー複写機の一例を示すブロック図である。
【符号の説明】
１…画像入力部、２…画像出力部、３…前段画像処理部、４…後段画像処理部、５…蓄積部、６…制御部、７…画像出力部、１１…階調補正部、１２…色空間変換部、１３…絵／文字分離部、１４…画像変倍部、１５…Ｔａｇ変倍部、１６…原稿検知部、２１…文字抽出部、２２…網点抽出部、２３…論理和演算部、２４…収縮部、２５…膨張部、２６…論理積演算部、２７…色／黒判定部、２８…結合部、３１…色空間変換部、３２…空間補正部、３３…階調補正部、３４…中間調生成部、３５…Ｔａｇ信号生成部、４１〜４３…色補正部、４４，４５…セレクタ、５１…基準データ用色補正メモリ、５２…補間用領域選択信号メモリ、５３〜５５…補間用信号出力メモリ、５６〜５８…補間用乗算器、５９…加算部、６１…ラインバッファ、６２〜６７…補正演算部、６８…セレクタ、７１〜８０…補正ＬＵＴ、８１…セレクタ、９１…画素値演算部、９２…演算係数＆パターン記憶部、９３…波形パターン記憶部、９４…比較部、９５…参照波生成部、１０１…減算器、１０２…乗算器、１０３，１０４…比較器、１０５…セレクタ、１１１〜１１３…符号化部、１１４〜１１６…復号化部、１１７…データ蓄積部、１１８…メモリコントローラ、１１９…バッファメモリ、１２０…バス、１２１…画像信号変倍部、１２２…Ｔａｇ信号変倍部、２０１…画像入力部、２０２…画像出力部、２０３…画像処理部、２１０…画像再現部、２１１…階調補正部、２１２…セレクタ、２１３…空間補正部、２１４…階調補正部、２１５…中間調生成部、２２０…画像蓄積・編集部、２２１…符号化部、２２２…復号化部、２２３…変倍部、２２４…画像蓄積部、２２５…メモリコントローラ、２２６…ページメモリ、２２７…バス、３０１…画像入力部、３０２…画像出力部、３０３…画像処理部、３０４…制御部、３１０…階調補正部、３１１…色補正部、３１２…墨版生成・下色除去部、３１３…画像信号変倍部、３１４…切換信号変倍部、３１５…空間補正部、３１６…階調補正部、３１７…中間調生成部、３１８…絵／文字分離部、３１９…原稿検知部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus and an image processing method having a function of accumulating image data, and in particular, an image processing apparatus suitable for use in processing image data requiring precise image processing such as a color image. And an image processing method.
[0002]
[Prior art]
In recent years, digital image input / output devices and related technologies have made significant progress and development. Along with this, images that handle various digital images such as digital copiers that read originals as digital signals and perform various image processing are printed. Processing equipment is rapidly spreading. For example, in a digital copying machine, a system having various advanced functions such as an electronic sorting function and page layout editing, which is impossible with a conventional optical copying machine, due to signal processing unique to digital. Various proposals have also been made.
[0003]
FIG. 35 is a block diagram showing an example of a conventional image copying system. In the figure, 201 is an image input unit, 202 is an image output unit, 203 is an image processing unit, 210 is an image reproduction unit, 211 is a gradation correction unit, 212 is a selector, 213 is a spatial correction unit, and 214 is a gradation correction unit. 215 is a halftone generation unit, 220 is an image storage / editing unit, 221 is an encoding unit, 222 is a decoding unit, 223 is a scaling unit, 224 is an image storage unit, 225 is a memory controller, 226 is a page memory, 227 is a bus.
[0004]
The image input unit 201 includes a document placement table, a light source, a CCD line sensor, an A / D (analog / digital) converter, and the like. When a one-dimensional CCD line sensor is used, the intensity of reflected light is determined by relatively moving the document in a direction (sub-scanning direction) perpendicular to the arrangement direction (main scanning direction) of the light receiving elements in the CCD line sensor. An electric signal of 8 bits / pixel corresponding to the above is generated.
[0005]
The image output unit 202 prints a monochrome image on a recording medium by a recording method such as an electrophotographic method.
[0006]
The image processing unit 203 receives an image signal output by the image input unit 201 scanning the document, and generates a signal that causes the image output unit 202 to reproduce the image on the document satisfactorily. As illustrated in FIG. 35, the image processing unit 203 includes an image reproduction unit 210 and an image accumulation / editing unit 220. The image reproduction unit 210 generates an output signal for reproducing an image by the image output unit 202 from the image signal received from the image input unit 201. The image storage / editing unit 220 stores document images in units of pages, and realizes sorting and layout editing.
[0007]
The image reproduction unit 210 includes a gradation correction unit 211, a selector 212, a space correction unit 213, a gradation correction unit 214, and a halftone generation unit 215. The gradation correction unit 211 corrects the gradation of the image signal input by the image input unit 201 according to the gradation characteristics of the image input unit 201. The selector 212 is controlled by a control unit (not shown), and selects either the image signal output from the gradation correction unit 211 or the image signal read from the image storage / editing unit 220. The spatial correction unit 213 corrects the spatial characteristics of the image signal selected by the selector 212. The tone correction unit 214 corrects the tone of the image signal according to the tone characteristics of the image output unit 202. The halftone generation unit 215 generates a binary signal for printing from the 8-bit / pixel image signal and outputs it to the image output unit 202.
[0008]
The image storage / editing unit 220 includes an encoding unit 221, a decoding unit 222, a scaling unit 223, an image storage unit 224, a memory controller 225, and a page memory 226, which are connected by a bus 227. The encoding unit 221 encodes the 8-bit / pixel image signal input from the gradation correction unit 211 of the image reproduction unit 210 by a predetermined multi-value image compression method represented by, for example, JPEG. The decoding unit 222 decompresses data encoded by a predetermined multi-level image compression method, and generates an image signal. The scaling unit 223 performs two-dimensional enlargement / reduction processing (in the main scanning direction and the sub-scanning direction) on the image signal. The image storage unit 224 stores the image data encoded by the encoding unit 221 in units of pages. A memory controller 225 controls the page memory 226 and is used for image rotation, layout editing, and the like. For example, rotation processing, mirror image processing, and the like can be realized by controlling a write address and a read address to the page memory 226. The page memory 226 temporarily stores image data during image rotation, layout editing, and the like.
[0009]
In the configuration shown in FIG. 35, for example, in a normal copy operation in which one copy of one original is copied, an image signal is not input to the image storage / edit unit 220. The image signal input by the image input unit 201 is subjected to correction processing by the gradation correction unit 211, the spatial correction unit 213, and the gradation correction unit 214 of the image reproduction unit 210, and binarized by the halftone generation unit 215. And output to the image output unit 202.
[0010]
When the above sort operation or page editing is performed, the image signal input by the image input unit 201 is subjected to gradation correction processing by the gradation correction unit 211 and then to the image storage / editing unit 220. Is output. The image signal input to the image storage / editing unit 220 is encoded by the encoding unit 221 and then stored in the image storage unit 224 in units of pages.
[0011]
For example, in order to realize an electronic sorting function for copying a predetermined number of copies in a collation mode, all originals are temporarily stored in the image storage unit 224 and then encoded from the image storage unit 224 in a predetermined order. The read image data is read out, decompressed by the decoding unit 222, and an image signal is output to the image reproduction unit 210. Further, when realizing editing such as enlargement / reduction, rotation, and various layouts, the image data held in the image storage unit 224 is expanded by the decoding unit 222, and the enlargement / reduction process is performed by the scaling unit 223. Or a rotation or writing to a predetermined position by the memory controller 225 to generate a desired image signal on the page memory 226. The image signal generated on the page memory 226 is output to the image reproduction unit 210 when it is printed as it is, and is compressed again by the encoding unit 221 when combined with a function such as the above-described electronic sort. Accumulated in the accumulation unit 224.
[0012]
The image signal input from the image storage / editing unit 220 to the image reproduction unit 210 is transmitted through the selector 212 in the spatial correction unit 213 and the gradation correction unit 214 in the same manner as the normal copy operation described above. Correction processing is performed, and the image is binarized by the halftone generation unit 215 and output to the image output unit 202.
[0013]
With the configuration and operation as described above, an advanced editing function can be realized as described above. However, in the case of an image processing apparatus that performs extremely high image quality and precise reproduction processing such as a digital color copying machine, for example, the configuration of the image reproduction unit becomes very complicated as described below. It was difficult to realize the same function.
[0014]
FIG. 36 is a block diagram showing an example of a conventional digital color copying machine. In the figure, 301 is an image input unit, 302 is an image output unit, 303 is an image processing unit, 304 is a control unit, 310 is a gradation correction unit, 311 is a color correction unit, 312 is a black plate generation / under color removal unit, 313 is an image signal scaling unit, 314 is a switching signal scaling unit, 315 is a spatial correction unit, 316 is a gradation correction unit, 317 is a halftone generation unit, 318 is a picture / character separation unit, and 319 is a document detection unit. is there.
[0015]
The image input unit 301 generates an electrical signal obtained by color-separating an image on a document into three primary colors such as red (R), green (G), and blue (B). The image output unit 302 prints, for example, four color toners such as yellow (Y), magenta (M), cyan (C), and black (K) by an electrophotographic method, and a full color image is recorded. Print on top. The image processing unit 303 receives RGB signals output by scanning the document with the image input unit 301, and outputs Y, M, C, and K signals that allow the image output unit 302 to reproduce the image on the document satisfactorily. Generate.
[0016]
In this system, scanning in the sub-scanning direction of the image input unit 301 and the image output unit 302 is synchronized. Further, as described above, when printing in four colors of Y, M, C, and K, the image input unit 301 scans the document four times, and the image processing unit 303 receives the input RGB signal and performs each time. For each scan, color signals are generated, for example, in the order of Y → M → C → K. Similarly, the image output unit 302 performs printing in the order of, for example, Y → M → C → K, and four-color full color printing is performed. Note that the control unit 304 controls the image input unit 301, the image output unit 302, and the image processing unit 303.
[0017]
A gradation correction unit 310 in the image processing unit 303 corrects the gradation characteristics of the image input unit 301 for the input RGB primary color image signals. The gradation correction unit 310 can realize gradation correction processing by referring to a one-dimensional LUT (lookup table) set in advance for each of R, G, and B signals, for example. The color correction unit 311 generates a YMC signal that matches the color characteristics of the color material used in the image output unit 302 from the RGB signal subjected to the gradation correction process. The color correction unit 311 can be realized by a known masking technique implemented by, for example, a 3 × 6 matrix operation.
[0018]
The black plate generation / under color removal unit 312 extracts a gray component from the YMC signal after color correction, and generates a Y / M / C / K signal in accordance with the print cycle of the image output unit 302. Specifically, after obtaining the K signal based on the minimum values of Y, M, and C, a known black plate generation that removes the lower color component from the Y, M, and C signals according to the determined K component・ Under color removal processing is performed.
[0019]
The image signal scaling unit 313 performs image reduction / enlargement processing in the main scanning direction by publicly known linear interpolation, and performs subtraction / reduction in the sub-scanning direction in accordance with the control of the scanning speed in the sub-scanning direction in the image input unit 301. Enlargement processing is performed to realize two-dimensional scaling processing for the input image. The switching signal scaling unit 314 scales the Tag signal output from the picture / character separation unit 318 described later at the same magnification as the image signal scaling unit 313. For the scaling process, for example, a known zero-order hold method or the like is used.
[0020]
The spatial correction unit 315 corrects the spatial characteristics of the input Y / M / C / K signal. For example, the input image space is obtained by multiplying a total of 35 pixels centering on the target pixel by ± 3 pixels in the main scanning direction and ± 2 pixels in the sub-scanning direction by adding a predetermined coefficient, that is, by performing a convolution operation. Correct the characteristics. The tone correction unit 316 corrects the tone characteristics of the image output unit 302. For example, it is realized by referring to a one-dimensional LUT (look-up table) set in advance for each signal of Y / M / C / K. The halftone generation unit 317 generates a Y / M / C / K binary signal to be output to the image output unit 302. For example, a binary signal is generated by comparing an input image signal with a dither matrix threshold designed in advance for each color signal of Y / M / C / K.
[0021]
The document detection unit 319 extracts information necessary for the copying operation from the document image, such as detecting the size and position of the document read by the image input unit 301 and determining whether the document is a monochrome document or a color document. This extraction processing can be performed, for example, during preliminary scanning performed prior to document reading scanning, and the extracted information is sent to the control unit 304.
[0022]
The picture / character separating unit 318 identifies whether each pixel of the document image is a character or a picture in units of pixels. Then, according to the identification result, the processing contents are switched for each pixel so that the black plate generation / under color removal unit 312, the space correction unit 315, the gradation correction unit 316, and the halftone generation unit 317 perform optimal processing. Generate and output a signal. Hereinafter, a signal used for switching or changing each image processing content corresponding to an image signal and a pixel unit in this way is described as a Tag signal. In this example, the picture / character separating unit 318 generates a Tag-1 signal, a Tag-2 signal, a Tag-3 signal, and a Tag-4 signal, and the black plate generation / undercolor removal unit 312, the space correction unit 315, Output to the tone correction unit 316 and the halftone generation unit 317.
[0023]
The contents of the Tag signal generated by the picture / character separation unit 318 are specified by an operator from an operation unit (not shown), for example, a document type such as “character”, “character / photo”, “map”, or “ It depends on the color mode such as “black and white”, “three colors”, “four colors”. Further, there may be a case where a plurality of document types and color modes are mixedly specified within the same document by inputting with an editing tablet (not shown) or filling in the document with a highlighter. In addition to the document type and color mode, for example, a Tag signal that controls the print color also corresponds to a designation such that a pixel identified as a black character in the picture / character separation unit 318 is reproduced in K single color. is necessary.
[0024]
Therefore, the picture / character separation unit 318 receives the input RGB image data, the operator setting information from the control unit 304, the information on the print color processed by the image processing unit 303, and the like. Tag-1 for controlling the black plate generation / undercolor removal unit 312, the space correction unit 315, the gradation correction unit 316, and the halftone generation unit 317 based on the determined information and the pixel / picture determination result Signal, Tag-2 signal, Tag-3 signal, Tag-4 signal are generated.
[0025]
With the above configuration, the image read by the image input unit 301 is processed for each pixel in accordance with various information such as the document type, color mode, and color in the image, and the image output unit 302 records the recording medium. Printed on top. In this way, an extremely high-quality color copy is possible.
[0026]
However, if an image storage / editing unit as shown in FIG. 35 is connected to an image processing system such as a digital color copying machine shown in FIG. 36, the following problems arise. First, the same reproduction processing, for example, tone correction, space correction, color correction, halftone generation, etc., is performed for all the components of the document such as halftone dots, characters, lines, fills, black characters, black lines, etc. Therefore, extremely high image quality cannot be realized. Therefore, a mechanism for making the reproduction process different for each component of the document, such as a picture / character separation unit 318 and a Tag signal in FIG. 36, is required.
[0027]
However, for example, in the digital color copying machine shown in FIG. 36, the number of bits of the Tag signal is 2 bits for the Tag-1 signal, 2 bits for the Tag-2 signal, 3 bits for the Tag-3 signal, and 1 for the Tag-4 signal. If a bit is required, a control signal of 8 bits per pixel is required. In the case of a digital color copying machine, the contents of these Tag signals vary depending on the printing color as described above. Therefore, if there are control signals for each of the four printing colors, it is necessary to process and control a Tag signal of 8 bits × 4 colors = 32 bits / pixel.
[0028]
Further, since the Tag signal is an instruction to switch processing in units of pixels, for example, the lossy compression such as JPEG is applied to the Tag signal of 8 bits / pixel or 32 bits / pixel, like the image signal. This is not desirable, and it is necessary to employ a reversible compression process for encoding. For this reason, the data amount of the Tag signal may rather be larger than the data amount of the image signal. Therefore, if the image storage / editing unit 220 shown in FIG. 35 is connected to an image processing apparatus that performs precise image processing such as the digital color copying machine shown in FIG. The capacity tag signal needs to be edited, such as accumulation, rotation, and layout, similar to the image signal. For this reason, since the image storage / editing unit becomes very large, an apparatus provided with an image storage / editing unit in an image processing apparatus that performs precise image processing such as a digital color copying machine has not been developed.
[0029]
As one measure for providing an image storage / editing unit in an image processing apparatus that performs precise image processing, before and after the tone correction unit 310 and the color correction unit 311 before the Tag signal generation, that is, the picture / character separation unit 318 Can be used for input / output with the image storage / editing unit. However, the image identification process performed by the picture / character separation unit 318 is an extremely precise recognition process. For example, if it is performed after a compression process such as JPEG, an erroneous recognition result due to the influence of block noise or mosquito noise caused by the compression. And a normal Tag signal may not be generated. Also, if compression processing is not performed on the image signal or lossless compression processing is performed, the data capacity handled by the image storage / editing unit becomes very large, resulting in a large-scale image storage / editing unit. There was a problem of becoming.
[0030]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an image processing apparatus and an image processing method capable of using a variety of advanced editing functions even when extremely high image quality is required. Is.
[0031]
[Means for Solving the Problems]
According to the present invention, in an image processing apparatus, image data storage means for storing input image data for at least one page and a plurality of attribute information corresponding to each page of the image data are stored in the image data storage means. Attribute information storage means for storing in association with the image data, image post-processing means for reading the image data stored in the image data storage means and performing various image processing, and image processing by the image post-processing means Control signal generation means for generating a control signal for controlling the image post-processing means in accordance with a plurality of attribute information stored in the attribute information storage means in association with the image data; The image processing is performed according to the control signal generated by the control signal generating means.
In the image processing method, at least one page of input image data is stored in the image data storage unit, and a plurality of attribute information corresponding to each page of the image data is stored in the image data storage unit. A control signal is generated by a control signal generation unit according to a plurality of attribute information stored in the attribute information storage unit in association with the image data, and is stored in the attribute data storage unit in association with the image data. The stored image data is read out, and image processing is performed on the image data by image post-processing means in accordance with the control signal generated by the control signal generating means.
In this way, together with image data, a plurality of attribute information corresponding to each page of the image data is accumulated, and a control signal is generated from the plurality of attribute information to perform various image processing. Processing and subsequent image processing can be controlled. For example, even when extremely high image quality is required, various and advanced editing functions can be realized.
[0032]
The attribute information may be pixel information necessary for editing processing in the editing unit extracted by the extraction unit from input image data, page information set by an operator input, or the like. These pixel information and page information can be stored separately. At this time, the attribute information accumulating unit accumulates pixel information indicating the identification result for each pixel extracted by the extracting unit, and the control signal for the subsequent image post-processing unit reads at least the pixel information from the attribute information accumulating unit. It can be generated by the control signal generating means. As a result, the amount of data stored in the attribute information storage means can be reduced.
[0033]
The image data stored in the image data storage means and the attribute information stored in the attribute information storage means are encoded and stored by the respective encoding means, and decoded by the respective decoding means when read out. Can be used. Thus, the amount of data to be accumulated can be reduced by applying an optimal encoding method to each data.
[0034]
Furthermore, for example, in the case of having image preprocessing means for performing image processing on the image data before being stored in the image data storage means after the pixel information is extracted by the extraction means, the attribute preprocessing is also performed on the attribute information. The image can be stored in the attribute information storage unit after similar image processing is performed by the unit.
[0035]
Further, in the configuration in which the image data input from the image input means is processed and output to the image output means, the image data and attribute data are accumulated in synchronization with the scanning of the image in the image input means, Image data and attribute data can be read and edited in synchronization with the image output means.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing an embodiment of an image processing apparatus according to the present invention. In the figure, 1 is an image input unit, 2 is an image output unit, 3 is a pre-stage image processing unit, 4 is a post-stage image processing unit, 5 is a storage unit, and 6 is a control unit. The example shown in FIG. 1 shows a case where the digital color copying machine is configured to have a page unit storage function.
[0037]
The image input unit 1 acquires an image on a document as a color image. The image input unit 1 includes, for example, a document placement table, a light source, a line sensor, an A / D (analog / digital) converter, and the like. By moving the one-dimensional CCD line sensor in a direction (sub-scanning direction) perpendicular to the arrangement direction (main scanning direction) of the light receiving elements of the line sensor, the image on the document is read and output as image data. Here, as an example, an electrical signal that is color-separated into three primary colors of red (R), green (G), and blue (B) is generated and output as an image signal. Of course, the reading method is arbitrary, and a method of reading the document by moving it may be used.
[0038]
The image output unit 2 forms a color image on a recording medium in accordance with input image data. Here, as an example, a full-color image is printed using four color toners of yellow (Y), magenta (M), cyan (C), and black (K). In this example, it is assumed that full color printing is performed by four printing operations in the order of Y → M → C → K.
[0039]
The pre-stage image processing unit 3 and the post-stage image processing unit 4 receive the image data output by the image input unit 1 scanning the document, and generate image data so that the image of the document is reproduced well in the image output unit 2. To do. Here, RGB signals are received from the image input unit 1, and Y, M, C, and K signals are sequentially generated for the image output unit 2. The pre-stage image processing unit 3 and the post-stage image processing unit 4 perform image processing performed until the image output unit 2 forms an image read by the image input unit 1 according to the positional relationship with the storage unit 105 described later. Divided.
[0040]
The accumulating unit 5 receives image data output from the pre-stage image processing unit 3 and attribute information (Tag signal) necessary for image processing, and accumulates and holds them in units of pages. It also provides additional functions such as output control of image data, image rotation / combination processing, sorting, double-sided printing, and Nup editing for arranging and outputting a plurality of pages in one sheet.
[0041]
The control unit 6 controls the pre-stage image processing unit 3, the post-stage image processing unit 4, and the storage unit 5. Further, it controls the image input unit 1 or acquires a synchronization signal from the image input unit 1, and synchronizes the image input operation in the image input unit 1 with the preceding image processing unit 3 and the storage unit 5 at the time of image input. Can do. Furthermore, the image output unit 1 can be controlled or a synchronization signal can be acquired from the image output unit 2, and the storage unit 5, the subsequent image processing unit 4, and the image output unit 2 can be synchronized.
[0042]
An outline of the operation in the embodiment of the image processing apparatus of the present invention will be briefly described. A document to be color-copied is read by the image input unit 1, and digital signals of the three primary colors R, G, and B are generated. The generated digital image signal is input to the pre-stage image processing unit 3, where the color system L defined by CIE (International Lighting Commission) 1976 from the three primary colors RGB. ^* a ^* b ^* Is converted into a digital signal represented by Further, the pre-stage image processing unit 3 also generates a Tag signal that is an attribute signal used to control various subsequent image processes. L generated by the pre-stage image processing unit 3 ^* a ^* b ^* The signal and the Tag signal are output to the storage unit 5. At this time, in synchronization with the document scanning operation of the image input unit 1, the preceding image processing unit 3 outputs L ^* a ^* b ^* The signal and the Tag signal are output and stored in the storage unit 5.
[0043]
L stored and stored in the storage unit 5 ^* a ^* b ^* After the predetermined image editing and processing are performed in the storage unit 5, the signal and the Tag signal are synchronized with the printing operation of the image output unit 2, the number of printing operations, here the number of output colors, and the subsequent image It is output to the processing unit 4. In the subsequent image processing unit 4, L ^* a ^* b ^* A Y / M / C / K signal for printing is sequentially generated from the signal and the Tag signal, and a printing signal is output to the image output unit 2. The image output unit 2 sequentially forms Y, M, C, and K images on the recording medium, thereby forming a full-color image.
[0044]
By the operation as described above, copying of a color original is realized. Accordingly, when copying a document by reproducing a color image with the usual four colors of Y / M / C / K and copying the document, the document image is fetched into the storage unit 5 by one scan, and the image data is read from the storage unit 5. And printing is performed by reading the Tag signal four times.
[0045]
Hereafter, each part shown in FIG. 1 is demonstrated in detail. FIG. 2 is a block configuration diagram illustrating an example of the pre-stage image processing unit 3. In the figure, 11 is a gradation correction unit, 12 is a color space conversion unit, 13 is a picture / character separation unit, 14 is an image scaling unit, 15 is a Tag scaling unit, and 16 is a document detection unit. In FIG. 2, the RGB signal input from the image input unit 1 is processed and L ^* a ^* b ^* The operation of outputting the signal and the Tag signal to the storage unit 5 will be described. In the figure, the solid line indicates an image signal, the broken line indicates a Tag signal, and the numbers described along with the diagonal lines in each signal line indicate the number of bits per pixel in each signal. The same applies to the subsequent drawings.
[0046]
Assume that the image input unit 1 scans an image on an original and outputs a digital signal of 8 bits / pixel for each color of RGB at a pixel density of 600 dpi (600 dots per 25.4 mm), for example. The gradation correction unit 11 corrects the gradation characteristics of the image input unit 1 with respect to RGB three primary color signals input from the image input unit 1. FIG. 3 is a graph showing an example of gradation correction processing in the gradation correction unit 11. In the gradation correction unit 11, for example, as shown in FIG. 3, gradation conversion processing is performed on each of the R, G, and B signals in accordance with a characteristic curve set in advance for each signal. Such conversion processing can be realized, for example, by referring to a preset one-dimensional LUT (lookup table).
[0047]
The color space conversion unit 12 calculates the L signal from the RGB signal that has been subjected to the gradation correction processing by the gradation correction unit 11. ^* a ^* b ^* Generate a signal. L generated by the color space conversion unit 12 ^* a ^* b ^* The signal is a value quantized to 8 bits / pixel in accordance with a color space region that can be read and output by the image input unit 1 and the image output unit 2, respectively. RGB signal to L ^* a ^* b ^* The color space conversion processing to the signal is, for example,
[Expression 1]

It can be realized by such an operation. In this equation, the conversion matrix coefficients α11 to α39 and β1 to β3 are numerical values designed in advance experimentally according to the color reading characteristics of the image input unit 1.
[0048]
The picture / character separating unit 13 identifies whether each pixel is a pixel constituting a picture or a pixel constituting a character, and outputs a signal indicating the identification result (hereinafter, Seg-Tag signal). . The picture / character separating unit 13 corresponds to an extracting unit. Further, the Seg-Tag signal indicating the identification result corresponds to pixel information which is one of the attribute information.
[0049]
FIG. 4 is a block diagram showing an example of the picture / character separating unit. In the figure, 21 is a character extraction unit, 22 is a halftone dot extraction unit, 23 is an OR operation unit, 24 is a contraction unit, 25 is an expansion unit, 26 is an AND operation unit, 27 is a color / black determination unit, and 28 is It is a coupling part. The picture / character separating unit 13 extracts character pixels in the image and separates them from the design and the background part. As described above, in the picture / character separating unit 13, the input L ^* a ^* b ^* A signal is received, and a 2 bit / pixel seg-Tag signal is output as an identification result. In the picture / character separation unit 13, the lightness signal L ^* Is input to the character extraction unit 21 and the halftone dot drawing unit 22. The character extraction unit 21 generates a binary signal indicating whether each pixel is a character pixel. The character extraction unit 21 extracts elements having a high gradation level such as characters, line drawings, and solids (filled) in the image. The character extraction unit 21 can be realized, for example, by obtaining a logical sum of a fixed binarization processing result based on a predetermined threshold and a floating binarization processing result using a peripheral pixel average value as a threshold. Similarly, the halftone dot extraction unit 22 generates a binary signal indicating whether each pixel is a halftone dot pixel. For example, as disclosed in Japanese Patent Application No. 9-231361, the halftone dot extraction unit 22 determines whether the pixel of interest is a halftone dot region based on the density or periodicity of the binarized image signal. Can be configured to.
[0050]
After obtaining the logical sum of the character signal and the halftone dot signal of each pixel obtained in this way by the logical sum operation unit 23, contraction and expansion processing of a predetermined size are performed by the contraction unit 24 and the expansion unit 25. The contraction unit 24 can perform contraction processing by performing a logical product operation on pixels in the window, for example, using a 31 × 31 (sub scan × main scan) size window. The expansion unit 25 can perform expansion processing by performing a logical OR operation on pixels in the window using, for example, a 49 × 49 size window. In addition, the size of the window used in the contraction part 24 and the expansion part 25 is arbitrary.
[0051]
Further, the logical product operation unit 26 calculates the logical product of the negation of the signal after the expansion processing by the expansion unit 25 and the logical sum signal of the character signal output from the logical sum operation unit 23 and the halftone signal. . Thus, a 1-bit / pixel character identification signal indicating a character pixel is generated.
[0052]
In the picture / character separating unit 13, L ^* a ^* b ^* The signal is input to the color / black determination unit 27. In the color / black determination unit 27, the input L ^* a ^* b ^* By comparing the signal with a predetermined threshold value for each signal, it is determined whether each pixel is a chromatic color or an achromatic color, and a 1-bit / pixel color / black identification signal is generated. Then, the character identification signal output from the logical product operation unit 26 and the color / black identification signal output from the color / black determination unit 27 are combined by the combining unit 28, and Seg− of 2 bits / pixel indicating three types. A Tag signal is generated. FIG. 5 is an explanatory diagram of an example of the Seg-Tag signal. As shown in FIG. 5, the Seg-Tag signal indicates three types of black characters and color characters, other than characters, by the value of 2 bits / pixel.
[0053]
Returning to FIG. 2, the image scaling unit 14 outputs the L output from the color space conversion unit 12. ^* a ^* b ^* In response to the signal, one-dimensional enlargement / reduction is performed in the main scanning direction. In combination with the enlargement / reduction in the main scanning direction in the image scaling unit 14 and the scanning speed control in the sub-scanning direction in the image input unit 1, two-dimensional enlargement / reduction of the document image is realized. For the enlargement / reduction in the image scaling unit 14, for example, a known linear interpolation operation or the like can be used. The image scaling unit 14 corresponds to image preprocessing means. The image preprocessing means may be a process other than the image scaling process.
[0054]
The Tag signal scaling unit 15 performs enlargement / reduction processing in the main scanning direction on the Tag signal at the same scaling factor as the image enlargement / reduction processing performed by the image scaling unit 14. As an enlargement / reduction method, for example, a known simple scaling method (zero-order hold method) can be used. Here, the Area-Tag signal shown in FIG. 2 is a Tag signal (attribute information) indicating a setting made by the operator for a document and a copying operation using a user interface (not shown) or an editing digitizer. FIG. 6 is an explanatory diagram of an example of an Area-Tag signal. Here, as shown in FIG. 6, signals representing “color mode” and “document type” are each 2 bits / pixel. As the color mode, image formation using four colors (YMCK), image formation using three colors (YMC), or monochrome image formation can be designated. As the document type, a character / photo mixed document, a character document, a photo document, a map document, or the like can be designated. The Tag signal scaling unit 15 performs enlargement / reduction processing on the Area-Tag signal together with the Seg-Tag signal output from the picture / character separation unit 13 at the same scaling factor as the image scaling unit 14. . The Tag signal scaling unit 15 corresponds to attribute preprocessing means. The attribute preprocessing unit may be a process other than the image scaling process, and may be any process that performs the same process as the image preprocessing unit.
[0055]
With the above configuration, the pre-stage image processing unit 3 receives the RGB signal from the image input unit 1, and ^* a ^* b ^* A signal and a Tag signal (Seg-Tag signal, Area-Tag signal) are output.
[0056]
The document detection unit 16 in FIG. 2 extracts information necessary for the copying operation from the document image, such as detecting the size and position of the document and determining whether the document is a monochrome document or a color document. For example, such information can be extracted during preliminary scanning performed prior to document reading scanning, and necessary information can be sent to the control unit 6.
[0057]
The control unit 6 performs automatic functions such as magnification setting, monochrome / color discrimination, paper selection, and tray selection based on copy conditions input from an operation unit (not shown) by the operator and information extracted from the original image by the original detection unit 16. Is realized.
[0058]
FIG. 7 is a block configuration diagram illustrating an example of the post-stage image processing unit 4. In the figure, 31 is a color space conversion unit, 32 is a space correction unit, 33 is a gradation correction unit, 34 is a halftone generation unit, and 35 is a Tag signal generation unit. Among these, the color space conversion unit 31, the space correction unit 32, the gradation correction unit 33, and the halftone generation unit 34 correspond to an image post-processing unit, and the Tag signal generation unit 35 corresponds to a control signal generation unit. The image post-processing means may have other various processing means in addition to these processing units.
[0059]
The color space conversion unit 31 receives L input to the subsequent image processing unit 4. ^* a ^* b ^* From the signal, Y / M / C / K signals used for printing in the image output unit 2 are sequentially generated according to the printing color cycle. FIG. 8 is a schematic configuration diagram illustrating an example of the color space conversion unit 31. In the figure, reference numerals 41 to 43 denote color correction units, and 44 and 45 denote selectors. In this example, the color space conversion unit 31 includes a color correction unit 41, a color correction unit 42, a color correction unit 43, and selectors 44 and 45. Here, the color correction unit 41, the color correction unit 42, and the color correction unit 43 are set with different color correction coefficients, and the input L ^* a ^* b ^* Color correction processing is performed according to the color correction coefficient set for each signal to generate a Y / M / C / K signal.
[0060]
Here, each color correction | amendment part 41-43 can be comprised as follows, for example. First, the Y / M / C / K signal output from the color correction unit 41 is a Y / M / C / K signal that has been subjected to color correction for four-color reproduction, and the document type is a photo and text / photo. Sometimes used. Similarly, the Y / M / C / K signal output from the color correction unit 42 is a Y / M / C / K signal that has been subjected to color correction for four-color reproduction, but is used when the document type is text or map. Is done. Here, the color correction for photographs and characters / photographs is a standard color correction that gives faithful reproduction to the original, and the YMC signal is changed to the K signal so that the graininess is not deteriorated in the reproduction of the photograph. The ratio to be replaced with (hereinafter referred to as UCR rate) is set to about 50%. On the other hand, the color correction for characters and maps is a color correction that assumes a graphics manuscript or a business document. A UCR rate is set. The signal output from the color correction unit 43 is a Y / M / C signal for three-color reproduction of Y, M, and C.
[0061]
L of input signal ^* Is used as a signal for reproducing black and white characters in a black and white mode and a document. The selector 45 receives a signal indicating a print color cycle (Cycle signal) input from the control unit 6 and outputs L when printing K color. ^* When a signal is output and other Y, M, and C colors are printed, the pixel value is reset by outputting “0”.
[0062]
The selector 44 is a Y / M / C / K signal output from the color correction unit 41, the color correction unit 42, and the color correction unit 43 according to a color space conversion switching signal (CC-Tag signal) described later, and a selector. L input from 45 ^* One of the four signals “0” is selected and output for each pixel. FIG. 9 is an explanatory diagram of an example of the CC-Tag signal. The CC-Tag signal is, for example, a signal of 2 bits / pixel. Depending on the combination of the respective bit values, the output of the color correction units 41 to 43 or L ^* It indicates whether a signal or “0” is selected.
[0063]
FIG. 10 is a schematic configuration diagram illustrating an example of the color correction units 41 to 43, and FIG. 11 is an explanatory diagram illustrating an example of a color space dividing method in the color correction units 41 to 43. In the figure, 51 is a reference data color correction memory, 52 is an interpolation area selection signal memory, 53 to 55 are interpolation signal output memories, 56 to 58 are interpolation multipliers, and 59 is an adder. Here, the color correction unit 41 is shown as an example, but the color correction unit 42 and the color correction unit 43 have the same configuration.
[0064]
As described above, the color correction units 41 to 43 perform L ^* a ^* b ^* A Y / M / C / K signal is generated from the signal, and can be realized using, for example, the method described in Japanese Patent Laid-Open No. 5-110840. The color correction units 41 to 43 in this example use the table memory set in advance to perform L ^* a ^* b ^* Y / M / C / (K) is generated from the above. L entered ^* a ^* b ^* The signal is divided into upper 4 bits and lower 4 bits, color correction is calculated using the color correction memory using the upper bits as an address, and color correction is performed by interpolating between them using an interpolation circuit using the lower 4 bits. can do.
[0065]
As shown in FIG. 11, the color correction units 41 to 43 have a three-dimensional L ^* a ^* b ^* L color space ^* , A ^* , B ^* Divide into cubes determined by the upper 4 bits of each. Then, the Y / M / C (/ K) output value corresponding to the vertex coordinates is stored as reference data.
[0066]
The divided cube is further divided into six tetrahedrons for interpolation calculation as shown in FIG. Input L ^* , A ^* , B ^* Is determined from the coordinate values defined by the upper 4 bits and the lower 4 bits. Then, an interpolation operation using Y / M / C (/ K) values corresponding to the four vertices of the tetrahedron to which it belongs is performed.
[0067]
In FIG. 10, the color correction memory 51 for reference data is L ^* a ^* b ^* This is a color correction memory that outputs reference data using a set of upper 4 bits of a signal as an address signal. The interpolation area selection signal memory 52 uses the set of lower 4 bits as an address signal, and the input L ^* , A ^* , B ^* It is determined which of the six tetrahedrons shown in FIG. Interpolation signal output memories 53, 54 and 55 receive the output of the upper 4 bits and the interpolation area selection signal memory 52, and output signals for interpolation calculation. The interpolation multipliers 56, 57, and 58 multiply the lower 4 bits of the input signal by the interpolation calculation signals (interpolation coefficients) output from the interpolation signal output memories 53, 54, and 55. The adder 59 adds the output signals of the reference data correction memory 51 and the interpolation multipliers 56, 57, and 58.
[0068]
In addition, a cycle signal indicating a change in print color in the image output 2 is input to the reference data color correction memory 51 and the interpolation signal output memories 53, 54, and 55. According to this Cycle signal, correction data for Y signal generation is output during Y color printing, and similarly, correction data for M signal / C signal / K signal generation is output during M color / C color / K color printing. In the color correction unit 41, the color correction unit 42, and the color correction unit 43, the operation described above causes L ^* a ^* b ^* A Y / M / C (/ K) signal is generated from the signal.
[0069]
FIG. 12 is a schematic configuration diagram illustrating an example of the space correction unit 32, and FIG. 13 is an explanatory diagram of an example of a convolution calculation process performed by the space correction unit 32. In the figure, 61 is a line buffer, 62 to 67 are correction arithmetic units, and 68 is a selector. The line buffer 61 performs a data delay of 6 lines in order to secure image data for 7 lines required for a spatial correction calculation described later. The correction calculation units 62 to 67 perform space correction calculation by, for example, convolution calculation. For example, as shown in FIG. 13, if the pixel of interest is (i, j), 7 × 9 (sub-scanning direction × main scanning direction) = (i−4, j−3) to (i + 4, j + 3) around it = Spatial correction processing can be realized for 63 pixels by convolution calculation using predetermined calculation coefficients φ11 to φ79. Here, the calculation coefficients φ11 to φ79 are spatial correction coefficients with a total sum of 1.0. Correction coefficients for the Y / M / C / K colors are set in advance in the correction calculation units 62 to 67, and a convolution calculation using the correction coefficient for the print color is performed in accordance with the cycle signal from the control unit 6. The
[0070]
As shown in FIG. 12, the spatial correction unit 32 includes six correction calculation units 62 to 67, and a 3-bit / pixel space generated from the Area-Tag signal and the Seg-Tag signal in the Tag signal generation unit 35. Based on the correction switching signal (Filter-Tag signal), the selector 68 selects and outputs the output values of the six correction calculation units 62 to 67 for each pixel.
[0071]
FIG. 14 is an explanatory diagram of an example of selection logic of the correction calculation unit 62 to the correction calculation unit 67 with respect to the value of the Filter-Tag signal and the processing content thereof. As illustrated in FIG. 14, one of the correction calculation results output from the correction calculation units 62 to 67 is selected according to the value of the Filter-Tag signal. In the correction calculation unit 62, spatial correction for the pattern image is performed. When the photo type is designated as the document type, and the value of the Seg-Tag signal that is the identification result in the picture / character separation unit 13 when the character / photo type is designated as the document type and “00 ( In the case of “other than characters” ”(see FIG. 5), the calculation result of the correction calculation unit 62 is selected.
[0072]
The correction calculation unit 63 performs space correction for characters. “01 (black character), 11 (color character)” in which the character / photo type is designated as the document type and the value of the Seg-Tag signal as the identification result in the picture / character separation unit 13 represents the character (see FIG. 5). ), The calculation result of the correction calculation unit 63 is selected.
[0073]
The correction calculation unit 64 performs spatial correction on graphics and solid (uniform color) elements frequently used in business documents and the like. When the character type is designated as the document type and the value of the Seg-Tag signal, which is the identification result in the picture / character separation unit 13, is “00 (other than characters)” (see FIG. 5), the correction calculation unit 64 Is selected.
[0074]
In the correction calculation unit 65, space correction for characters that has a higher degree of emphasis than the correction calculation unit 63 performs. “O1 (black character), 11 (color character)” (see FIG. 5) in which the character type is designated as the document type and the value of the Seg-Tag signal as the identification result in the picture / character separation unit 13 represents the character. In this case, the calculation result of the correction calculation unit 65 is selected.
[0075]
In the correction calculation unit 66, spatial correction for the map is performed. When a map type is designated as the document type, the calculation result of the correction calculation unit 66 is selected.
[0076]
The correction calculation unit 67 performs space correction for a black and white original mainly composed of characters, line drawings, and the like. When the color mode is black and white and the character type is designated as the document type, the calculation result of the correction calculation unit 67 is selected. Spatial correction is performed by the above-described configuration and operation.
[0077]
FIG. 15 is a schematic configuration diagram illustrating an example of a gradation correction unit. In the figure, reference numerals 71 to 80 denote correction LUTs, and 81 denotes a selector. The correction LUTs 71 to 80 each perform gradation correction processing. For example, it can be realized by a known LUT (lookup table) referring to a one-dimensional table. Output values for the respective colors Y / M / C / K are set in advance in the correction LUTs 71 to 80, and an output value is obtained by referring to a predetermined address of the LUT based on the cycle signal and the input pixel value from the control unit 6.
[0078]
As shown in FIG. 15, the gradation correction unit 33 includes a correction LUT 71 to a correction LUT 80 and a selector 81. Based on the 4-bit / pixel gradation correction switching signal (TRC-Tag signal) generated from the Area-Tag signal and the Seg-Tag signal in the Tag signal generation unit 35, the selector 81 generates ten correction calculation units 71-71. The output value of 80 is selected for each pixel and output.
[0079]
FIG. 16 is an explanatory diagram of an example of selection logic of the correction LUTs 71 to 80 with respect to the value of the TRC-Tag signal and processing contents thereof. As shown in FIG. 16, according to the value of the TRC-Tag signal, one of the output signals of the correction LUTs 71 to 80 is selected by the selector 81 and output. Here, the correction LUT 71 to the correction LUT 75 are color original gradation correction LUTs, and are used when the color mode is “four colors (00), three colors (01)” (see FIG. 6). The correction LUT 76 to the correction LUT 80 are correction LUTs for reproducing black and white originals or color originals, and are used when the color mode is “black and white (10)” (see FIG. 6).
[0080]
In the correction LUT 71, gradation correction for the pattern image is performed. When the photo type is designated as the document type, and the value of the Seg-Tag signal that is the identification result in the picture / character separation unit 13 when the character / photo type is designated as the document type and “00 ( In the case of “other than characters)” (see FIG. 5), the output value of the correction LUT 71 is selected.
[0081]
In the correction LUT 72, gradation correction for characters is performed. “01 (black character), 11 (color character)” in which the character / photo type is designated as the document type and the value of the Seg-Tag signal as the identification result in the picture / character separation unit 13 represents the character (see FIG. 5). ), The output value of the correction LUT 72 is selected.
[0082]
In the correction LUT 73 and the correction LUT 74, gradation correction is performed on an original such as a business document having many characters and line drawings, and gradation correction with higher contrast than the correction LUT 71 and the correction LUT 72 is set. The correction LUT 73 performs gradation correction on graphics and solid (uniform color) elements that are frequently used in business documents and the like. When the character type is specified as the document type and the value of the Seg-Tag signal, which is the identification result in the picture / character separation unit 13, is “00 (other than characters)” (see FIG. 5), the output of the correction LUT 73 A value is selected. The correction LUT 74 is a character gradation correction LUT. “01 (black character), 11 (color character)” (see FIG. 5) in which the character type is designated as the document type and the value of the Seg-Tag signal as the identification result in the picture / character separation unit 13 represents the character. In this case, the calculation result of the correction LUT 74 is selected.
[0083]
The correction LUT 75 is an LUT for gradation correction of a high-definition document as represented by a map. When the map type is designated as the document type, the output value of the correction LUT 75 is selected.
[0084]
Even when the monochrome mode is selected, tone correction is set with the same logic as in the case of color reproduction described above. In the correction LUT 76, gradation correction for the pattern image is performed. When the photograph type is designated as the document type, and when the character / photo type is designated as the document type and the value of the Seg-Tag signal that is the identification result in the picture / character separation unit 13 is “01 ( In the case of “other than characters” ”(see FIG. 5), the output value of the correction LUT 76 is selected.
[0085]
In the correction LUT 77, gradation correction for characters is performed. “01 (black character), 11 (color character)” in which the character / photo type is designated as the document type and the value of the Seg-Tag signal, which is the identification result in the picture / character separating unit 13, represents the picture (see FIG. 5). ), The output value of the correction LUT 77 is selected.
[0086]
In the correction LUT 78 and the correction LUT 79, gradation correction is performed on a document such as a business document with many characters and line drawings. Gradation correction with higher contrast than that of the correction LUT 76 and the correction LUT 77 is set. The correction LUT 78 performs gradation correction for graphics and solid (uniform color) elements that are frequently used in business documents and the like. When the character type is specified as the document type and the value of the Seg-Tag signal, which is the identification result in the picture / character separation unit 13, is “00 (other than characters)” (see FIG. 5), the output of the correction LUT 78 A value is selected.
[0087]
The correction LUT 79 is a character gradation correction LUT. “01 (black character), 11 (color character)” (see FIG. 5) in which the character type is designated as the document type and the value of the Seg-Tag signal as the identification result in the picture / character separation unit 13 represents the character. In this case, the calculation result of the correction LUT 79 is selected.
[0088]
The correction LUT 80 is an LUT intended for gradation correction of a high-definition document as represented by a map. When the map type is designated as the document type, the output value of the correction LUT 80 is selected. The gradation correction is performed by the configuration and operation as described above.
[0089]
FIG. 17 is a schematic configuration diagram illustrating an example of the halftone generation unit 34. In the figure, 91 is a pixel value calculation unit, 92 is a calculation coefficient & pattern storage unit, 93 is a waveform pattern storage unit, 94 is a comparison unit, and 95 is a reference wave generation unit. The halftone generation unit 34 shown in FIG. 17 is an LD (laser diode) of the image output unit 2 from an 8-bit Y / M / C / K signal per pixel as proposed in, for example, Japanese Patent Laid-Open No. 9-121283. ) To generate a binary signal for ON / OFF control.
[0090]
The pixel value calculation unit 91 calculates a pixel value for generating a desired screen from the Y / M / C / K signal by calculation described later. The calculation coefficient & pattern unit 92 stores a pattern matrix and calculation coefficients required by the pixel value calculation unit 91, and an input halftone generation switching signal (Screen-Tag signal) and a cycle from the control unit 6. In accordance with the signal, a predetermined coefficient and pattern are sent to the pixel value calculation unit 91. FIG. 18 is an explanatory diagram of an example of a calculation pattern matrix. As shown in FIG. 18, the calculation pattern matrix can be data similar to a threshold matrix used in known dither processing, and the calculation coefficient is a numerical value indicating the number of threshold steps in the pattern matrix. FIG. 18 shows a case where there are 16 computation coefficients and a case where there are 17 computation coefficients.
[0091]
The waveform pattern storage unit 93 stores a calculation pattern stored in the calculation coefficient & pattern storage unit 92 and a waveform pattern corresponding to the calculation coefficient. FIG. 19 is an explanatory diagram of an example of a waveform pattern. FIGS. 19A and 19B are waveform patterns corresponding to FIGS. 18A and 18B, respectively. The waveform patterns A, B, and C will be described later. Similarly to the calculation coefficient & pattern storage unit 92, the waveform pattern storage unit 93 generates a reference signal for selecting a 2-bit waveform pattern per pixel in accordance with the input screen-tag signal and the cycle signal from the control unit 6. The data is sent to the unit 95.
[0092]
The reference wave generation unit 95 generates a triangular wave of any of the reference wave A, the reference wave B, and the reference wave C according to a signal indicating the waveform pattern stored in the waveform pattern storage unit 93 and sends it to the comparison unit 94 To do. FIG. 20 is an explanatory diagram of the generation process of the reference wave and the output signal. The reference wave generation unit 95 generates one of the three types of reference waves shown in FIG. 20A, that is, a reference wave A that gradually increases, a reference wave B that gradually decreases, and a reference wave C that has a triangular waveform. And output to the comparator 94.
[0093]
The comparison unit 94 converts the 8-bit / pixel digital image signal output from the pixel value calculation unit 91 into an analog signal, compares the analog signal with the reference wave input from the reference wave generation unit 95, and outputs the LD. A binary signal for controlling is output. In FIG. 20B, the comparison unit 94 shows a stepped signal as a signal after D / A conversion of the signal output from the pixel value calculation unit 91. This signal is compared with the reference wave A, reference wave B, and reference wave C generated by the reference wave generation unit 95, and a signal that is ON when the reference wave is smaller and OFF when it is larger is a binary signal. Output. As a result, the binary signal shown as the LD lighting waveform in FIG. 20B is output. By controlling the lighting of the LD in accordance with this binary signal, an output image whose width changes according to the image signal output from the pixel value calculation unit 91 is formed as shown in FIG. 20B as an output image. . When the reference wave A is used, the recorded portion is shifted to the left, when the reference wave B is used, it is shifted to the right, and when the reference wave C is used, the recorded portion is shifted to the center. In this way, the halftone generation unit 34 realizes highly accurate printing position control by controlling the waveform pattern.
[0094]
FIG. 21 is a block diagram illustrating an example of the pixel value calculation unit 91. In the figure, 101 is a subtracter, 102 is a multiplier, 103 and 104 are comparators, and 105 is a selector. The Y / M / C / K input signal is input to the subtractor 101. The other value of the subtracter 101 is input with a value indicated by a calculation pattern sent at a predetermined interval based on the matrix size in synchronization with the input signal from the calculation coefficient & pattern storage unit 92. Reduced from. Next, the multiplier 102 multiplies the difference value between the input signal and the calculation pattern by the calculation coefficient sent from the calculation coefficient & pattern storage unit 92. Then, the comparator 103 and 104 and the selector 105 are controlled so that the selector 103 selects “255” for a pixel having a value higher than 255, and the comparator 104 has a value lower than 0. The pixel 105 having the control is controlled so that “0” is selected by the selector 105.
[0095]
With the configuration described above, the halftone generation unit 34 can form a halftone image having a plurality of types of lines and angles by switching calculation coefficients and reference waves for each pixel.
[0096]
FIG. 22 is an explanatory diagram of an example of the number of lines corresponding to the Screen-Tag signal and the processing content thereof. In the following description, refer to FIG. 6 for the values of the color mode and the document type, and to FIG. 5 for the Seg-Tag signal. As shown in FIG. 22, when the Screen-Tag signal is “00”, a 150-line dot screen with excellent gradation is formed, which is selected when the document type is “10 (photo)”. .
[0097]
When the Screen-Tag signal is “01”, a 200-line line screen having excellent gradation and less moire is formed, the document type is “00 (character / photo)”, and the picture / character When the identification result (Seg-Tag signal) in the separation unit 13 is “00 (other than characters)”, the color mode is “00 (4 colors) and 01 (3 colors)”, and the document type is “01 (characters)”. ”And the identification result (Seg-Tag signal) in the picture / character separation unit 13 is“ 00 (other than characters) ”.
[0098]
Subsequently, when the screen-Tag signal is “10”, a 300-line line screen is formed in which fine character and line drawing element information is not lost. This is selected when the document type is “11 (map)”. Is done.
[0099]
Finally, when the Screen-Tag is “11”, a 600-line line screen is formed. This is because the document type is “00 (character / photo)” and the identification result in the picture / character separation unit 13 (Seg -Tag signal) is generated for pixels when “01 or 11 (character)” and when the color mode is “10 (monochrome)” and the document type is “01 (character)”.
[0100]
23 and 24 are explanatory diagrams of examples of Tag signals generated by the Tag signal generation unit 35. FIG. The Tag signal generation unit 35 temporarily stores the color space conversion unit 31 and the space correction from the two Tag signals that are once stored in the storage unit 5 and input to the subsequent image processing unit 4, that is, the Area-Tag signal and the Seg-Tag signal. The unit 32, the gradation correction unit 33, and the halftone generation unit 34 generate a pixel unit processing switching signal and various Tag signals. Here, the Tag signal generation unit 35 is a 2-bit CC− used by the color space conversion unit 31 in accordance with 64 combinations indicated by a total of 6 bits of 4 bits for the Area-Tag signal and 2 bits for the Seg-Tag signal. Tag signal, 3-bit Filter-Tag signal used in the spatial correction unit 32, 4-bit TRC-Tag signal used in the gradation correction unit 33, and 2-bit Screen-Tag signal used in the halftone generation unit 34 Are output respectively. The Tag signal generation unit 35 is realized, for example, by referring to a table of predetermined Tag signal generation logic. 23 and 24 are tables showing the Tag signal generation logic. According to the Tag signal generation logic, a CC-Tag signal, a Filter-Tag signal, a TRC-Tag signal, and a Screen-Tag signal are generated and output from the input Area-Tag signal and Seg-Tag signal, respectively.
[0101]
FIG. 25 is a schematic configuration diagram illustrating an example of the storage unit 5. In the figure, reference numerals 111 to 113 denote an encoding unit, 114 to 116 denote a decoding unit, 117 denotes a data storage unit, 118 denotes a memory controller, 119 denotes a buffer memory, and 120 denotes a bus. The storage unit 5 is input in synchronization with the document scanning operation of the image input unit 1. ^* , A ^* , B ^* L is stored and held in synchronization with the printing operation of the number of print colors of the image output unit 2. ^* , A ^* , B ^* The signal is output. In addition, the storage unit 5 also realizes a sorting function such as stack and collation, for example, and a page editing function such as rotation, Nup, signature, and double-sided printing, which are designated by an operation unit (not shown). Further, the Area-Tag signal and Seg-Tag signal output from the pre-stage image processing unit 3 are also stored in association with the input image data, and these signals are output when the corresponding image data is read out. .
[0102]
8 bits / pixel L input to the storage unit 5 ^* a ^* b ^* The signal is input to the encoding unit 113. In the encoding unit 113, for example, a predetermined image compression method represented by JPEG or the like is used for each page, and in each page ^* , A ^* , B ^* The image signal is encoded for each plane, and the image data is output to the data storage unit 117 via the bus 120. The encoding unit 113 corresponds to the first encoding unit.
[0103]
L ^* a ^* b ^* The 4-bit / pixel Area-Tag signal input in synchronization with the signal is input to the encoding unit 111, encoded by a known lossless compression method such as run-length encoding, and the like via the bus 120. It is stored in the data storage unit 117. Similarly L ^* a ^* b ^* A 2-bit / pixel Seg-Tag signal input in synchronization with the signal is input to the encoding unit 112, encoded by a known lossless compression method such as run-length encoding, and the like via the bus 120. It is stored in the data storage unit 117. The encoding unit 111 and the encoding unit 112 correspond to a second encoding unit.
[0104]
The data accumulating unit 117 includes L encoded by the encoding unit 111, the encoding unit 112, and the encoding unit 113. ^* a ^* b ^* Input image data, Area-Tag signal, and Seg-Tag signal are stored in units of pages. The data storage unit 117 can be realized by a large-capacity storage device capable of storing encoded image data and Tag signal data over a plurality of pages, such as a hard disk device. The data storage unit 117 corresponds to both the image data storage unit and the attribute data storage unit.
[0105]
The decryption unit 116 reads the image data stored in the data storage unit 117 in units of pages, and synchronizes with the printing operation of the image output unit 2 by a predetermined decompression method. ^* a ^* b ^* The signal is decoded and output to the subsequent image processing unit 4. The decoding unit 116 corresponds to the first decoding unit.
[0106]
Similarly, the decoding unit 114 reads the Area-Tag data stored in units of pages in the data storage unit 117, and decodes the Area-Tag signal by a predetermined expansion method in synchronization with the printing operation of the image output unit 2. And output to the subsequent image processing unit 4. The decoding unit 115 reads the Seg-Tag data stored in units of pages in the data storage unit 117, decodes the Seg-Tag signal by a predetermined decompression method in synchronization with the printing operation of the image output unit 2, and Output to the image processing unit 4. The decoding unit 114 and the decoding unit 115 correspond to the second decoding unit.
[0107]
The buffer memory 119 and the memory controller 118 are editing means used when performing page editing such as rotation processing, Nup composition, and signature.
[0108]
In FIG. 25, an encoding unit 111, an encoding unit 112, an encoding unit 113, a decoding unit 114, a decoding unit 115, a decoding unit 116, a data storage unit 117, and a memory controller 118 are connected by a bus 120. It is.
[0109]
Hereinafter, the sorting function and the page editing function performed in the storage unit 5 will be described. FIG. 26 is an explanatory diagram illustrating an example of a sort function realized by the storage unit 5. Here, a case where four copies of four originals as shown in FIG. FIG. 26B shows a copy result in the collation mode, and FIG. 26C shows a copy result in the stack mode.
[0110]
In this embodiment, the document image read in the image input unit 1 is subjected to various processes in the preceding image processing unit 3, ^* a ^* b ^* Converted to a signal. And L ^* a ^* b ^* The signal is input to the storage unit 5 together with the Seg-Tag signal generated by the picture / character separation unit 13 and the Area-Tag signal transmitted from the control unit. After being compressed by the corresponding encoding unit in the storage unit 5, it is stored in the data storage unit 117 in units of pages.
[0111]
In the case of collation mode copying as shown in FIG. 26B, all original reading operations are performed first. That is, image signal data and Tag signal data of a four-page document (“A”, “B”, “C”, “D”) are stored in the data storage unit 117. Thereafter, the image signal data and the Tag signal data are decoded by a predetermined method in accordance with the printing operation in the image output unit 2, and output to the subsequent image processing unit 4. Here, the image signal data, the Area-Tag signal data, and the Seg− in the order of the first page (A) → second page (B) → third page (C) → fourth page (D) from the data storage unit 117. The Tag signal data is read out, and the decoding unit 116, the decoding unit 114, and the decoding unit 115 perform decoding processing. Thereafter, in synchronization with the printing operation of the image output unit 2, L ^* a ^* b ^* The image signal, Area-Tag signal, and Seg-Tag signal are output to the subsequent image processing unit 4.
[0112]
In the case of stack mode copy as shown in FIG. 26C, the first original (“A”) is read by the input unit 101, and image signal data and Tag signal data are completely accumulated in the data accumulation unit 117. Similarly, the second and subsequent originals (“B”, “C”, “D”) are read and stored in the same manner, and in accordance with the printing operation in the image output unit 2, the first original (“ A ”) image signal data and Tag signal data are decoded by a predetermined method and output to the subsequent image processing unit 4. The decoding and output of the image signal data and Tag signal data of the first original (“A”) are repeated a predetermined number of copies (here, 4 copies). If printing of the predetermined number of copies of the first document is completed and image signal data and tag signal data have been stored in the data storage unit 117 of the second document (“B”), then 1 is continued. Similar to the case of the second sheet, the second sheet is printed by a predetermined number of copies. Stack mode copying can be performed by executing the above operation on the third document (C) and the fourth document (D).
[0113]
FIG. 27 is an explanatory diagram of an example of a rotation process that is one of the page editing functions. In the figure, the FS direction and the SS direction indicate a main scanning direction and a sub scanning direction, respectively. The same applies to the following description. FIG. 27A shows a case where an image is read by placing it on a document placing table (not shown) of the image input unit 1 in a state where the orientation of the document image is different. In such a case, as shown in FIG. 27B, an operation for aligning the direction of the output copy is performed by rotating the image. At this time, it is possible to improve the productivity of image printing by performing rotation processing so that the long side is the main scanning direction and the length in the sub-scanning direction is shortened. In the example shown in FIG. 27, the directions of the images “A” and “D” are different from those of the images “B” and “C”. In this case, by rotating the images “A” and “D” so as to coincide with the directions of the images “B” and “C” having long sides in the main scanning direction, the copy directions can be aligned. it can.
[0114]
FIG. 28 is an explanatory diagram of an example of a rotation process involving an enlargement / reduction process. In the example shown in FIG. 28, for example, reading and accumulation in the case of copying originals of different sizes such as A3 and A4 onto the same size paper are shown. In FIG. 28A, for example, the second and third sheets (“B” and “C”) are A4 size documents, and the first and fourth sheets (“A” and “D”) are A3 sizes. Indicates the manuscript. Here, the first and fourth sheets (“A” and “D”) cannot be read with the long side in the main scanning direction due to the restrictions of the image input unit 1, so that the image scaling unit of the preceding image processing unit 3 14, the reduction process is performed, and the storage unit 5 stores image signal data having different lengths in the main scanning direction and the sub-scanning direction as shown in FIG.
[0115]
Even in such a case, as shown in FIG. 28C, an operation for aligning the direction of the output copy is performed by rotating the image whose size has been aligned by the reduction process. At this time, it is possible to improve the productivity of image printing by performing the rotation process so that the long side is the main scanning direction and the length in the sub-scanning direction is shortened.
[0116]
Whether or not to perform rotation processing on the image depends on copy conditions input by an operator from an operation unit (not shown) and document information obtained by preliminary scanning using the document detection unit 16 in the preceding image processing unit 3. Based on this, the control unit 6 determines and the operation of the storage unit 5 is controlled.
[0117]
The image rotation processing in the storage unit 5 is realized using the buffer memory 119 and the memory controller 118. When printing a document to be rotated, the image signal data and the corresponding Area-Tag signal data and Seg-Tag signal data are read from the data storage unit 117 prior to the printing operation in the image output unit 2. Decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115, respectively. Thereafter, a predetermined rotation process is performed by the memory controller 118 and stored in the buffer memory 119. The rotation process can be performed, for example, by address control at the time of storing in or reading from the buffer memory 119.
[0118]
The buffer memory 119 is L ^* a ^* b ^* It is composed of a total of four page memories comprising three 8-bit / pixel page memories for image signals and one 6-bit / pixel page memory for Area-Tag signal data and Seg-Tag signal data. Can do. After a predetermined rotation process is performed, L stored and held in the buffer memory 119 ^* a ^* b ^* The image signal data, the Area-Tag signal data, and the Seg-Tag Tag signal data are read in synchronization with the printing operation in the image output unit 2, and are decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115. Are decoded and sent to the subsequent image processing unit 4.
[0119]
Further, when the rotation process occurs in the collation mode, the copy productivity is lost if the rotation process is repeated. Therefore, after a predetermined rotation process is performed, L stored and held in the buffer memory 119 is stored. ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag tag signal data may be encoded again by the encoding unit 113, the encoding unit 111, and the encoding unit 112, respectively, and stored in the data storage unit 117. . After processing for all document images and Tag signal data that require rotation processing is completed and storage in the data storage unit 117 is completed, the L of the corresponding page is synchronized with the printing operation in the image output unit 2. ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are read out, decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115, and then sent to the subsequent image processing unit 4. Is done.
[0120]
FIG. 29 is an explanatory diagram of an example of a “Nup function” for placing and printing a plurality of pages of a document on one sheet. FIG. 29A shows a document, and here, four documents “A”, “B”, “C”, and “D” are illustrated. FIG. 29B shows 2up editing, and FIG. 29C shows 4up editing. The Nup process in this embodiment can be realized by using the buffer memory 119 and the memory controller 118 in the same manner as the rotation process described above.
[0121]
In the case of 2up editing as shown in FIG. 29 (B), first and second (“A” and “B”) originals are first read, and the respective encoded image signal data and Tag are read. The signal data is stored in the data storage unit 117. Next, the image signal data, the Area-Tag signal data, and the Seg-Tag signal data of the first document (“A”) are read out and decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115. After that, the memory controller 118 controls the data so as to have the arrangement as shown in FIG. Subsequently, the second document (“B”) is stored in a predetermined address in the buffer memory 119 so as to be arranged alongside the first document (“A”) through the same processing. L of the first and second originals (“A” and “B”) held in the buffer memory 119 as described above. ^* a ^* b ^* The image data, Area-Tag signal data, and Seg-Tag signal data are read out as a set of one image and Tag signal in synchronization with the printing operation in the image output unit 2, and the decoding unit 116, the decoding unit 114, bypass the decoding process in the decoding unit 115, and send to the subsequent image processing unit 4. The same processing is performed on the third and fourth originals (“C” and “D”) to realize two 2-up copies.
[0122]
In the case of collation copying or the like as in the rotation processing described above, after performing 2up processing for all pages, encoding is performed and the data is stored in the data storage unit 117, thereby increasing copy productivity. It is possible.
[0123]
As shown in FIG. 29C, the 4up editing can be realized in the same manner as the 2up editing described above. First, all the first to fourth originals (“A”, “B”, “C”, “D”) are read and each encoded L ^* a ^* b ^* Image signal data and Tag signal data are stored in the data storage unit 117. Next, L of the first document ("A") ^* a ^* b ^* The image data, the Area-Tag signal data, and the Seg-Tag signal data are read out and decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115, and then the direction as shown in FIG. The memory controller 118 performs rotation processing and write control so as to be arranged, and the data is stored at a predetermined address in the buffer memory 119. Subsequently, the second, third, and fourth originals (“B”, “C”, and “D”) are also processed in the same manner, and the same as the first original (“A”). It is stored in the buffer memory 119 so as to be arranged at a predetermined orientation. L of the four originals (“A”, “B”, “C”, “D”) held in the buffer memory 119 as described above. ^* a ^* b ^* The image data, Area-Tag signal data, and Seg-Tag signal data are read out as a set of one image and Tag signal in synchronization with the printing operation in the image output unit 2, and the decoding unit 116, the decoding unit 114, bypass the decoding process in the decoding unit 115, and send to the subsequent image processing unit 4.
[0124]
FIG. 30 is an explanatory diagram of an example of an editing function effective when creating a booklet or the like. It is possible to perform more advanced page editing by combining the rotation processing and arrangement control as described above. For example, as shown in FIG. 30, an editing function for creating a plurality of booklets and the like can be realized. FIG. 30A shows eight originals {reading of originals is performed in the order of “A”, “B”, “C”, “D”, “E”, “F”, “G”, “J”. ). FIGS. 30B, 30 </ b> C, and 30 </ b> D illustrate output results of page editing performed according to each binding direction. In addition, the hatched pages in FIGS. (B), (C), and (D) indicate that they are back pages, and the dot sequence of black circles ('●') is bound by, for example, a stapler or glue at the time of binding. Represents the binding allowance portion. In double-sided printing, the image output unit 2 temporarily accumulates paper on a predetermined tray after front side printing, and then reverses the paper to perform back side printing. In the case of paper reversal, it is assumed that the reversal is performed such that the upper right corner of each front surface and the lower right corner of the back surface of FIG.
[0125]
FIG. 30B shows the arrangement of the originals in the 2up copy mode in which two pages of originals are arranged in order and when duplex printing is designated. The first and second originals (“A” and The upper end of the first page composed of “B”) is set as the binding margin. In this case, the storage unit 5 can obtain a desired output by performing the same processing as the above-described 2up.
[0126]
First, input all first to eighth originals (“A”, “B”, “C”, “D”, “E”, “F”, “G”, “J”) Read in part 1, L ^* a ^* b ^* Image data, Area-Tag signal data, and Seg-Tag signal data are output to the storage unit 5. In the storage unit 5, the input image signal and Tag signal are encoded by the encoding unit 113, the encoding unit 111, and the encoding unit 112 using a predetermined compression method, respectively, and then stored in the data storage unit 117 in units of pages. Hold. Next, L of the first document (“A”) ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are read out and decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115, and then arranged as shown in FIG. Is controlled by the memory controller 118 and stored in a predetermined address in the buffer memory 119. Subsequently, the second document (“B”) is subjected to the same processing, and stored at a predetermined address in the buffer memory 119 so as to be arranged side by side with the first document (“A”). L of the first and second originals (“A” and “B”) held in the buffer memory 119 as described above. ^* a ^* b ^* The image data, the Area-Tag signal data, and the Seg-Tag signal data are encoded again by the encoding unit 113, the encoding unit 111, and the encoding unit 112 as one page image signal and Tag signal, respectively, and the data storage unit 117 Stored in
[0127]
Thereafter, the same processing is performed for the third and fourth originals (“C” and “D”), the fifth and sixth originals (“E” and “F”), the seventh and eighth sheets. 4 pages L for printing in the data storage unit 117. ^* a ^* b ^* Image data, Area-Tag signal data, and Seg-Tag signal data are held. After all the page layout processing, encoding processing, and storage processing in the data storage unit 117 are completed, the image is composed of images of the document “A” and the document “B” in synchronization with the printing operation in the image output unit 2. L of the first page ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are read out, decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115, and then sent to the subsequent image processing unit 4. Is done. Hereinafter, the second page composed of images of the document “C” and the document “D”, the third page composed of images of the document “E” and the document “F”, the documents “G” and the document “J”. By outputting the fourth page composed of images and repeating the operation for the set number of copies, page editing as shown in FIG. 30B becomes possible.
[0128]
FIG. 30C shows duplex printing in the 2up copy mode as in FIG. 30B, but the binding margin is composed of the first and second sheets (“A” and “B”) of the document. It is set at the left edge of the first page. Therefore, as shown in FIG. 30 (C), two sheets are printed at the time of 2up editing for backside printing (compared to 2up editing for front side printing) so that the top / bottom / right / left sides of the booklet are normal. It is necessary to perform a 180 degree rotation process so that the left and right relations of the original are reversed and the top and bottom of both pages are reversed.
[0129]
First, input all first to eighth originals (“A”, “B”, “C”, “D”, “E”, “F”, “G”, “J”) Read in part 1, L ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are output to the storage unit 5. In the storage unit 5, the input image signal and Tag signal are encoded by the encoding unit 113, the encoding unit 111, and the encoding unit 112 using a predetermined compression method, respectively, and then stored in the data storage unit 117 in units of pages. Hold. Next, L of the first document (“A”) ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are read out and decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115, and then arranged as shown in FIG. Is controlled by the memory controller 118 and stored in a predetermined address in the buffer memory 119. Subsequently, the second document (“B”) is stored in a predetermined address in the buffer memory 119 so as to be arranged alongside the first document (“A”) through the same processing.
[0130]
L of the first and second originals (A and B) held in the buffer memory 119 as described above. ^* a ^* b ^* The image signal data, the Area-Tag signal data, and the Seg-Tag signal data are encoded again by the encoding unit 113, the encoding unit 111, and the encoding unit 112 as one page image signal and Tag signal, respectively, and the data storage unit 117 is stored.
[0131]
Next, L of the third original ("C") ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are read out and decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115, and then arranged as shown in FIG. The memory controller 118 performs rotation processing and arrangement control so that the data is stored in the buffer memory 119 at a predetermined address. Similarly, the fourth document (“D”) is subjected to rotation processing and placement control by the memory controller 118 and is arranged in a predetermined manner in the buffer memory 119 so as to be placed side by side with the third document (“C”). Stored at the address. In this way, the L of the third and fourth originals (“C” and “D”) held in the buffer memory 119. ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are encoded as one-page image signals and Tag signals, respectively, as with the first and second originals ("A" and "B"). The data is encoded again by the encoding unit 113, the encoding unit 111, and the encoding unit 112 and stored in the data storage unit 117.
[0132]
Hereinafter, for the fifth and sixth originals (“E” and “F”), the same processing as that for the first and second originals (“A” and “B”) is performed on seven sheets. The same processing as that of the third and fourth originals (“C” and “D”) is performed on the first and eighth originals (“G” and “J”), respectively, and the data storage unit 117 4 pages L for printing ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are held.
[0133]
After all the page layout processing, encoding processing, and storage processing in the data storage unit 117 are completed, the image is composed of images of the document “A” and the document “B” in synchronization with the printing operation in the image output unit 2. L of the first page ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are read out, decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115, and then sent to the subsequent image processing unit 4. Is done. Hereinafter, the second page composed of the images of the document “C” and the document “D”, the third page composed of the images of the document “E” and the document “F”, the document “G”, and the document “J”. By outputting the fourth page composed of images and repeating the operation for the set number of copies, page editing as shown in FIG. 30C becomes possible.
[0134]
FIG. 30D illustrates a case of bookbinding in which the center of the output image is bound. Such page editing is called “signature editing”, and is largely different from the page editing shown in FIGS. 30B and 30C described above in that the order of reading the original and the order of printing do not match at all. Different. In the signature editing, the image reading operation is the same as the page editing shown in FIGS. First, all the first to eighth originals “A”, “B”, “C”, “D”, “E”, “F”, “G”, “J”) are input to the image input unit. Read with 1, L ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are output to the storage unit 5. In the storage unit 5, the input image signal and Tag signal are encoded by the encoding unit 113, the encoding unit 111, and the encoding unit 112 using a predetermined compression method, respectively, and then stored in the data storage unit 117 in units of pages. Hold.
[0135]
Next, as shown in FIG. 30D, the L of the eighth original (“J”) constituting the output of the first page. ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are read and decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115, and then arranged as shown in FIG. Is controlled by the memory controller 118 and stored in a predetermined address in the buffer memory 119. Subsequently, the first document (“A”) is stored in a predetermined address in the buffer memory 119 so as to be arranged alongside the eighth document (J) through the same processing. As described above, L of the eighth and first originals ("J" and "A") held in the buffer memory 119 is stored. ^* a ^* b ^* The image signal data, the Area-Tag signal data, and the Seg-Tag signal data are encoded again by the encoding unit 113, the encoding unit 111, and the encoding unit 112 as one page image signal and Tag signal, respectively, and the data storage unit 117 is stored.
[0136]
Next, L of the seventh original (“G”) ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are read and decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115, and then arranged as shown in FIG. The memory controller 118 performs rotation processing and arrangement control so that the data is stored in the buffer memory 119 at a predetermined address. Similarly, the second manuscript (“B”) is subjected to rotation processing and placement control by the memory controller 118, and the predetermined number in the buffer memory 119 is arranged so as to be arranged side by side with the seventh manuscript (“G”). Stored at the address. The Lth of the seventh and second originals (“G” and “B”) held in the buffer memory 119 in this way. ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are respectively encoded as an image signal and Tag signal of one page, as in the case of the eighth and first originals ("J" and "A"). The data is encoded again by the encoding unit 113, the encoding unit 111, and the encoding unit 112 and stored in the data storage unit 117.
[0137]
Thereafter, the sixth and third originals (“F” and “C”) are processed in the same manner as the eighth and first originals (“J” and “A”). The fifth and fourth originals (“E” and “D”) are processed in the same manner as the seventh and second originals (“G” and “B”). Then, in the data storage unit 117, four pages for printing L ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are held.
[0138]
After all the page layout processing, encoding processing, and storage processing in the data storage unit 117 are completed, the document “J” and the document “A” are configured in synchronization with the printing operation in the image output unit 2. L of the first page ^* a ^* b ^* Image signal data, Area-Tag signal data, and Seg-Tag signal data are read out, decoded by the decoding unit 116, the decoding unit 114, and the decoding unit 115, and then sent to the subsequent image processing unit 4. Is done. Hereinafter, the second page composed of images of the document “G” and the document “B”, the third page composed of images of the document “F” and the document “C”, the documents “E” and the document “D”. By outputting the fourth page composed of images and repeating the operation for the set number of copies, page editing as shown in FIG. 30D becomes possible.
[0139]
As described above, in the storage unit 5, the Tag signal is held and stored separately into information set by the operator in units of pages for the document and the image identification result in the pre-stage image processing unit 3. Then, information required for each processing unit is generated in the subsequent image processing unit 4 in accordance with the printing color and printing operation of the image output unit 2 at the time of image output. As a result, the amount of information stored in the storage unit 5 can be reduced. Further, since the accuracy of the position information input by the operator from the operation panel or the editing digitizer is usually about 0.25 mm (100 dpi), the information is logically separated in this way and the compression process is performed. The encoding efficiency in the encoding unit 111 is also greatly improved.
[0140]
As described above, the configuration of the digital color copying machine as shown in the above-described embodiment enables a variety of advanced functions such as an electronic sorting function and page layout editing even when extremely high image quality is required. It is possible to realize a simple editing function.
[0141]
In this embodiment, for the sake of explanation, the color mode, the document type, the identification type in the picture / character separation unit, the processing order of each processing unit, the switching of the processing, and the details of the combination logic are described. It goes without saying that the present invention is not limited to this.
[0142]
FIG. 31 is a block diagram showing another embodiment of the image processing apparatus of the present invention, FIG. 32 is a schematic diagram showing an example of the former image processing unit, and FIG. 33 is an example of the latter image processing unit. FIG. 34 is a schematic configuration diagram showing an example of the storage unit. In the figure, the same parts as those in FIGS. 1, 2, 7, and 25 are denoted by the same reference numerals, and the description thereof is omitted. 7 is an image output unit, 121 is an image signal scaling unit, and 122 is a Tag signal scaling unit.
[0143]
In this embodiment, the storage unit 5 has a configuration having an image signal scaling unit 121 and a Tag signal scaling unit 122 on a bus 120. The image signal scaling unit 121 performs two-dimensional enlargement / reduction processing on the image signal data. The method of enlargement / reduction processing is arbitrary, and a known method can be used. Further, the Tag signal scaling unit 122 performs enlargement / reduction processing on the Tag signal at the same scaling factor as the enlargement / reduction processing in the image signal scaling unit 121. The method in this case is also arbitrary. In addition, since the image signal scaling unit 121 and the Tag signal scaling unit 122 are provided in the storage unit 5, the image scaling unit 14 and the Tag scaling unit 15 are provided in the preceding image processing unit 3 as shown in FIG. Not provided. Also in this example, the image signal scaling unit 121 and the Tag signal scaling unit 122 shown in FIG. 34 constitute image preprocessing means and attribute preprocessing means.
[0144]
With such a configuration, it is possible to always perform image input at the image input unit 1 at the same magnification. Further, since the image signal scaling unit 121 and the Tag signal scaling unit 122 perform the reduction / enlargement processing based on the document information extraction results in the control unit 6 and the document detection unit 16 in the pre-stage image processing unit 3, Scanning is unnecessary.
[0145]
In this embodiment, the image output unit 7 has an electrophotographic process of YMCK four-color exposure / development / transfer, and can print a full-color image at a time. Therefore, L from the storage unit 5 to the subsequent image processing unit 4 ^* a ^* b ^* The image signal data and the Tag signal are output only once.
[0146]
As described above, even if the basic operations of image input and image output change, the image processing operation can be performed without substantially changing the configuration and operation in the above-described embodiment.
[0147]
In each of the above-described embodiments, RGB signals are received from the image input unit 1 and YMCK signals are sent to the image output unit 2 and the image output unit 7. However, the present invention is not limited to this. For example, the input side is L ^* a ^* b ^* , YMCK, and other various color spaces. The output side may also output a signal corresponding to the color space of the image data received by the image output unit 2. Note that the image output unit 2 is not limited to the electrophotographic system using toner as in the above-described example, and various recording systems such as an ink jet system, a thermal system, and a thermal transfer system can be used. .
[0148]
In each of the above-described embodiments, an image is transmitted from the image input unit 1 and a processed image is output to the image output unit 2. However, the present invention is not limited to this, and for example, a host It is also possible to configure as a printer connected directly to a computer or via a network. Furthermore, the output destination is not the image output unit 2 but can be configured in various forms such as a host computer. In such a case, the various types of image processing performed by the pre-stage image processing unit 3, the post-stage image processing unit 4, and the storage unit 5 are not limited to the functions described above, and may be appropriately selected. Of course, other functions may be added.
[0149]
【The invention's effect】
As is apparent from the above description, according to the present invention, for example, in an image processing system such as a color copying machine that requires extremely high image quality, various functions such as an electronic sorting function and page layout editing are provided. There is an effect that an advanced editing function can be realized.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram showing an embodiment of an image processing apparatus of the present invention.
FIG. 2 is a block configuration diagram illustrating an example of a pre-stage image processing unit 3;
FIG. 3 is a graph illustrating an example of gradation correction processing in a gradation correction unit 11;
FIG. 4 is a block diagram illustrating an example of a picture / character separating unit.
FIG. 5 is an explanatory diagram of an example of a Seg-Tag signal.
FIG. 6 is an explanatory diagram of an example of an Area-Tag signal.
7 is a block configuration diagram showing an example of a post-stage image processing unit 4. FIG.
FIG. 8 is a schematic configuration diagram illustrating an example of a color space conversion unit 31.
FIG. 9 is an explanatory diagram of an example of a CC-Tag signal.
FIG. 10 is a schematic configuration diagram illustrating an example of color correction units 41 to 43;
FIG. 11 is an explanatory diagram illustrating an example of a color space dividing method in the color correction units 41 to 43;
12 is a schematic configuration diagram showing an example of a space correction unit 32. FIG.
FIG. 13 is an explanatory diagram of an example of a convolution operation process performed in the space correction unit 32;
FIG. 14 is an explanatory diagram of an example of selection logic of the correction calculation unit 62 to the correction calculation unit 67 for the value of the Filter-Tag signal and the processing content thereof.
FIG. 15 is a schematic configuration diagram illustrating an example of a gradation correction unit.
FIG. 16 is an explanatory diagram of an example of selection logic of the correction LUTs 71 to 80 with respect to the value of the TRC-Tag signal and processing contents thereof;
FIG. 17 is a schematic configuration diagram illustrating an example of a halftone generation unit 34;
FIG. 18 is an explanatory diagram of an example of a calculation pattern matrix.
FIG. 19 is an explanatory diagram of an example of a waveform pattern.
FIG. 20 is an explanatory diagram of a generation process of a reference wave and an output signal.
21 is a block diagram illustrating an example of a pixel value calculation unit 91. FIG.
FIG. 22 is an explanatory diagram of an example of the number of lines corresponding to a Screen-Tag signal and the processing content thereof;
FIG. 23 is an explanatory diagram of an example of a Tag signal generated by the Tag signal generation unit 35;
FIG. 24 is an explanatory diagram (continuation) of an example of a Tag signal generated by the Tag signal generation unit 35;
25 is a schematic configuration diagram showing an example of a storage unit 5. FIG.
FIG. 26 is an explanatory diagram illustrating an example of a sort function realized by the storage unit 5;
FIG. 27 is an explanatory diagram of an example of a rotation process which is one of page editing functions.
FIG. 28 is an explanatory diagram of an example of a rotation process with an enlargement / reduction process;
FIG. 29 is an explanatory diagram of an example of a “Nup function” for placing and printing a plurality of pages of originals on a single sheet of paper.
FIG. 30 is an explanatory diagram showing an example of an editing function effective when creating a booklet or the like.
FIG. 31 is a block diagram showing another embodiment of the image processing apparatus of the present invention.
FIG. 32 is a schematic configuration diagram illustrating an example of a pre-stage image processing unit in another embodiment of the image processing apparatus of the present invention.
FIG. 33 is a schematic block diagram showing an example of a subsequent image processing unit in another embodiment of the image processing apparatus of the present invention.
FIG. 34 is a schematic configuration diagram showing an example of an accumulation unit in another embodiment of the image processing apparatus of the present invention.
FIG. 35 is a block diagram illustrating an example of a conventional image copying system.
FIG. 36 is a block diagram showing an example of a conventional digital color copying machine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image input part, 2 ... Image output part, 3 ... Pre-stage image processing part, 4 ... Subsequent image processing part, 5 ... Accumulation part, 6 ... Control part, 7 ... Image output part, 11 ... Tone correction part, 12 ... Color space conversion unit, 13 ... Picture / character separation unit, 14 ... Image scaling unit, 15 ... Tag scaling unit, 16 ... Document detection unit, 21 ... Character extraction unit, 22 ... Halftone extraction unit, 23 ... Logic Sum operation unit, 24 ... contraction unit, 25 ... expansion unit, 26 ... logical product operation unit, 27 ... color / black determination unit, 28 ... combination unit, 31 ... color space conversion unit, 32 ... space correction unit, 33 ... floor Tone correction unit, 34 ... halftone generation unit, 35 ... Tag signal generation unit, 41 to 43 ... color correction unit, 44, 45 ... selector, 51 ... color correction memory for reference data, 52 ... area selection signal memory for interpolation, 53 to 55: Signal output memory for interpolation, 56 to 58: Multiplier for interpolation, 59: Adder, 61: Line buffer , 62 to 67: Correction calculation unit, 68: Selector, 71-80: Correction LUT, 81: Selector, 91 ... Pixel value calculation unit, 92 ... Calculation coefficient & pattern storage unit, 93 ... Waveform pattern storage unit, 94 ... Comparison 95: Reference wave generator 101: Subtractor 102: Multiplier 103, 104 ... Comparator 105 ... Selector 111-113 Encoder 114-116 Decoder 117: Data storage 118: Memory controller, 119 ... Buffer memory, 120 ... Bus, 121 ... Image signal scaling unit, 122 ... Tag signal scaling unit, 201 ... Image input unit, 202 ... Image output unit, 203 ... Image processing unit, 210: Image reproduction unit, 211: Gradation correction unit, 212: Selector, 213 ... Spatial correction unit, 214 ... Gradation correction unit, 215 ... Halftone generation unit, 220 ... Image storage / editing unit, DESCRIPTION OF SYMBOLS 21 ... Encoding part, 222 ... Decoding part, 223 ... Scaling part, 224 ... Image storage part, 225 ... Memory controller, 226 ... Page memory, 227 ... Bus, 301 ... Image input part, 302 ... Image output part, DESCRIPTION OF SYMBOLS 303 ... Image processing part, 304 ... Control part, 310 ... Tone correction part, 311 ... Color correction part, 312 ... Black plate production | generation / under color removal part, 313 ... Image signal scaling part, 314 ... Switching signal scaling part 315: Spatial correction unit, 316: Tone correction unit, 317: Halftone generation unit, 318: Picture / character separation unit, 319: Document detection unit.

Claims (11)

  Image data storage means for storing at least one page of input image data, and attributes for storing a plurality of attribute information corresponding to each page of the image data in association with the image data stored in the image data storage means An information storage means; an image post-processing means for reading out the image data stored in the image data storage means and performing various image processing; Control signal generating means for generating a control signal for controlling the image post-processing means in accordance with a plurality of attribute information stored in the storage means, and the image post-processing means is generated by the control signal generating means An image processing apparatus that performs image processing according to a control signal.   Image data storage means for storing at least one page of input image data, and attributes for storing a plurality of attribute information corresponding to each page of the image data in association with the image data stored in the image data storage means An information storage means; an image post-processing means for reading out the image data stored in the image data storage means and performing various image processing; Control signal generating means for generating a control signal for controlling the image post-processing means in accordance with a combination of a plurality of attribute information stored in the storage means, and the image post-processing means is the control signal generating means An image processing apparatus that performs image processing according to a generated control signal.   2. The editing apparatus according to claim 1, further comprising an editing unit that performs an editing process on the image data stored in the image data storage unit in association with the attribute information based on the attribute information. The image processing apparatus according to 2.   The image processing apparatus according to claim 1, wherein the attribute information includes page information set by input by an operator.   2. The image processing apparatus according to claim 1, further comprising: extraction means for extracting pixel information necessary for editing processing in the editing means from input image data, wherein the attribute information includes the pixel information extracted by the extraction means. The image processing apparatus according to any one of claims 4 to 4.   Extraction means for extracting pixel information indicating an identification result for each pixel of the input image data, and the attribute information storage means inputs the pixel information extracted by the extraction means and the operator as the attribute information 5. The page information set by doing so is stored individually in association with each page of the image data stored in the image data storage means. The image processing apparatus according to item.   Furthermore, the first encoding means for encoding the image data stored in the image data storage means, the first decoding means for decoding the image data stored in the image data storage means, and the attribute information storage A second encoding means for encoding attribute information stored in the means, and a second decoding means for decoding attribute information stored in the attribute information storage means. The image processing apparatus according to claim 1.   Further, image preprocessing means for performing image processing on the image data before being stored in the image data storage means, and attribute information before being stored in the attribute information storage means, similar to the image preprocessing means. 8. The image processing apparatus according to claim 1, further comprising attribute preprocessing means for performing image processing.   And an image input means for inputting image data, and an image output means for outputting the image data edited by the editing means. The input of the image data in the image input means, and the image data Storage in the image data storage means and storage of attribute information associated with the image data in the attribute information storage means is performed in synchronization with scanning of the image in the image input means and storage in the image data storage means. The reading of the image data being read and the reading of the attribute information stored in association with the image data in the attribute information storage means are performed a required number of times in synchronization with the image output means. The image processing apparatus according to any one of claims 1 to 8.   The input image data is stored in the image data storage means for at least one page, and a plurality of attribute information corresponding to each page of the image data is associated with the image data stored in the image data storage means. A control signal is generated by a control signal generation unit according to a plurality of attribute information stored in the storage unit, associated with the image data, and stored in the attribute information storage unit, and the image data stored in the image data storage unit is An image processing method comprising: performing image processing on the image data by an image post-processing unit in accordance with a control signal read out and generated by the control signal generation unit.   The input image data is stored in the image data storage means for at least one page, and a plurality of attribute information corresponding to each page of the image data is associated with the image data stored in the image data storage means. The image stored in the storage unit, the control signal generating unit generates a control signal according to a combination of a plurality of attribute information stored in the attribute information storage unit in association with the image data, and the image data stored in the image data storage unit An image processing method comprising: reading data and performing image processing on the image data by an image post-processing unit in accordance with a control signal generated by the control signal generation unit.

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