JP2004128808A - Method and apparatus for image processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for image processing which can suppress a deterioration of an image quality occurring in a digital variable power process, a resolution converting process, and an image compression by controlling an amount of symbols of compressed image data. <P>SOLUTION: An image I/O system 100 includes a reader 200 for inputting image data, a controller 110 for generating coded data by coding the image data by a predetermined coding parameter, decoding the coded data and generating coded image data, and a printer 300 for outputting decoded image data. In this case, the coded data are stored in a memory, etc., in the system, an output format of the image data output from the printer 300 is designated, and the coding parameter is decided based on its output format. The coded data stored in the memory, etc., are converted based on the output format, stored in the memory, etc., in the system, and the stored coded data are decoded. <P>COPYRIGHT: (C)2004,JPO

Description

【００７５】
上式において、Ｒ、Ｇ、Ｂが入力、Ｘ、Ｙ、Ｚが出力、ａ１１、ａ１２、ａ１３、ａ２１、ａ２２、ａ２３、ａ３１、ａ３２、ａ３３、ｂ１、ｂ２、ｂ３、ｃ１、ｃ２、ｃ３がそれぞれ係数である。
【００７６】
上式の演算によって、例えば、ＲＧＢ色空間からＹｕｖ色空間への変換等の各種の色空間変換を行うことができる。
【００７７】
次に、マトリックス演算後のデータに対して、ＬＵＴ８０４による変換を行う。これによって、非線形の変換を行うことができる。尚、スルーのテーブルを設定することにより、実質的にＬＵＴ変換を行わないようにすることもできる。その後、色空間変換部８０３は、色空間変換処理された画像データをバスコントローラ１１３に転送する。色空間変換処理された画像データを受け取ったバスコントローラ１１３は、ＤＲＡＭ１１６若しくはＩ／Ｆ上の各デバイスにデータを転送する。
【００７８】
＜画像二値化部８０５の説明＞
次に、画像二値化部８０５における処理手順を示す。Ｉ／Ｆ１３７を介して、ＣＰＵ１１２からバスコントローラ１１３に二値化制御のための設定を行う。この設定によりバスコントローラ１１３は、画像二値化部８０５に対して二値化処理に必要な設定（変換方法に応じた各種パラメータ等）を行う。必要な設定を行った後に、再度ＣＰＵ１１２からバスコントローラ１１３に対して画像データ転送の許可を行う。この許可に従い、バスコントローラ１１３はＤＲＡＭ１１６若しくは各Ｉ／Ｆを介して、接続されているデバイスから画像データの転送を開始する。
【００７９】
画像二値化部８０５は、受け取った画像データに対して二値化処理を施す。本実施形態では、二値化の手法として画像データを所定の閾値と比較して単純に二値化するものとする。尚、ディザ法、誤差拡散法、誤差拡散法を改良したもの等のいずれの手法によってもかまわない。
【００８０】
その後、画像二値化部８０５は二値化処理された画像データをバスコントローラ１１３に転送する。二値化処理された画像データを受け取ったバスコントローラ１１３は、ＤＲＡＭ１１６若しくはＩ／Ｆ上の各デバイスにデータを転送する。
【００８１】
＜ＰＤＬ画像出力時のシーケンスの説明＞
図１１は、本発明の一実施形態における画像入出力システム１００でのＰＤＬ画像出力の手順を説明するためのフローチャートである。ＰＤＬ画像を出力する場合、まず、ＰＣ４０１上でユーザが当該ＰＤＬ画像出力ジョブのプリント設定を行う（ステップＳ１１１）。ここで、プリント設定内容は、部数、用紙サイズ、片面／両面、ページ出力順序、ソート出力、ステイプル止めの有無等である。
【００８２】
次に、ＰＣ４０１上で印刷指示を与え、それと共にＰＣ４０１上にインストールされているドライバソフトウェアが、印刷対象となるＰＣ４０１上のコードデータをいわゆるＰＤＬデータに変換して、ステップＳ１１１で設定したプリント設定パラメータとともに、画像入出力システム１００の制御装置１１０に、ネットワーク４００を介してＰＤＬデータを転送する（ステップＳ１１２）。
【００８３】
さらに、制御装置１１０のメインコントローラ１１１のＣＰＵ１１２が、コネクタ１２２及びネットワークコントローラ１２１を介して転送されたＰＤＬデータをプリント設定パラメータに基づいて、画像データに展開（ラスタライズ）する（ステップＳ１１３）。画像データの展開は、ＤＲＡＭ１１６上に行われる。画像データの展開が完了するとステップＳ１１４へ進む。
【００８４】
ステップＳ１１４では、メインコントローラ１１１がＤＲＡＭ１１６上に展開された画像データをグラフィックプロセッサ１３５に転送する。
【００８５】
次いで、グラフィックプロセッサ１３５が、プリント設定パラメータとは独立に画像処理を行う（ステップＳ１１５）。すなわち、本実施形態に係る画像入出力システム１００では、グラフィックプロセッサ１３５による画像変換処理が、画像回転、画像変倍、色空間変換、又は二値化処理を行って復号化データをディジタル変換することを特徴とする。
例えば、プリント設定パラメータで指定された用紙サイズがＡ４であるにもかかわらず、プリンタ部３００の給紙ユニット３６０にはＡ４Ｒ用紙しかない場合には、グラフィックプロセッサ１３５で画像を９０度回転することによって、出力用紙にあわせた画像出力を行うことができる。画像データの画像処理が完了するとステップＳ１１６へ進む。
【００８６】
ステップＳ１１６では、グラフィックプロセッサ１３５がメインコントローラ１１１へ画像処理後の画像データを転送する。メインコントローラ１１１は転送されてきた画像データをＤＲＡＭ１１６上に記憶する。
【００８７】
次いで、メインコントローラ１１１はプリンタＩ／Ｆ１４５及びコネクタ１４７を介して、プリンタ部３００を制御しつつ、適切なタイミングでＤＲＡＭ１１６上の画像データを、プリンタ部３００へと転送する（ステップＳ１１７）。
【００８８】
そして、制御装置１１０がプリンタ部３００を制御して、画像データをプリント出力する（ステップＳ１１８）。画像データの転送が完了すると（すなわち、当該ＰＤＬジョブが終了すると）プリント出力を終了する。
【００８９】
＜コピー画像出力時のシーケンス＞
図１２は、本発明の一実施形態に係る画像入出力システム１００におけるコピー画像出力の手順を説明するためのフローチャートである。コピー画像を出力する場合、操作部１５０上でユーザが当該コピー画像出力ジョブのコピー設定を行う（ステップＳ１２１）。コピー設定内容は、部数、用紙サイズ、片面／両面、拡大／縮小率、ソート出力、ステイプル止めの有無等である。
【００９０】
次に、操作部１５０上でコピー開始指示を与えると、制御装置１１０のメインコントローラ１１１はスキャナＩ／Ｆ１４０及びコネクタ１４２を介してリーダー部２００を制御し、原稿の画像データの読み込み動作を行う。まず、原稿給送ユニット２５０は、載置された原稿を１枚ずつプラテンガラス２１１上へ給送し、その際同時に原稿のサイズを検知する。検知された原稿のサイズに基づいて原稿を露光走査することにより画像データを読み取る。読み取られた画像データは、ＤＲＡＭ１１６上に記憶される（ステップＳ１２２）。
【００９１】
従来のコピー機では、コピー設定における拡大／縮小率の設定に応じて、すなわち副走査方向の変倍率に応じて光学ユニット２１３の移動速度を変化させることにより副走査方向の変倍処理を実現していた。しかしながら、本実施形態では、コピー設定における拡大／縮小率の設定にかかわらず、必ず等倍（１００パーセント）で画像データを読み取り、変倍処理については、主走査方向、副走査方向ともに、後述するグラフィックプロセッサ１３５によって行うものとする。
【００９２】
次いで、メインコントローラ１１１がＤＲＡＭ１１６上の画像データを、グラフィックプロセッサ１３５に転送する（ステップＳ１２３）。
【００９３】
さらに、グラフィックプロセッサ１３５が、コピー設定パラメータに基づいて画像処理を行う（ステップＳ１２４）。例えば、拡大４００パーセントの設定がなされているときには、グラフィックプロセッサ１３５内のモジュールである画像変倍部８０２を用いて主走査方向、副走査方向、双方への変倍処理を行う。画像データの画像処理が完了するとステップＳ１２５へ進む。
【００９４】
ステップＳ１２５では、グラフィックプロセッサ１３５がメインコントローラ１１１へ画像処理後の画像データを転送する。メインコントローラ１１１は転送されてきた画像データをＤＲＡＭ１１６上に記憶する。
【００９５】
さらに、メインコントローラ１１１は、プリンタＩ／Ｆ１４５及びコネクタ１４７を介して、プリンタ部３００を制御しつつ、適切なタイミングでＤＲＡＭ１１６上の画像データをプリンタ部３００へと転送する（ステップＳ１２６）。
【００９６】
そして、制御装置１１０が、プリンタ部３００を制御して画像データをプリント出力する（ステップＳ１２７）。画像データの転送が完了すると（すなわち、当該コピージョブが終了すると）プリント出力を終了する。
【００９７】
＜変倍率に応じた読み取り領域の決定と符号化パラメータ選択の説明＞
図１３は、等倍（１００パーセント）コピー時の画像処理の概略を示すブロック図である。Ａ４サイズ原稿５１０８をスキャナ５１０１で読み取った画像データは、ＪＰＥＧエンコーダ５１０２に入力されてリアルタイム圧縮が施される。エンコーダ５１０２で符号化する際には、目標とする圧縮率に対応する符号化パラメータ５１０６がエンコーダ５１０２に入力される。圧縮された符号データ５１０９は、符号メモリ５１０３に蓄積される。
【００９８】
次に、符号データ５１０９をＪＰＥＧデコーダ５１０４へ入力し、デコードされた画像データ５１１０がプリンタ５１０５へ入力され、Ａ４用紙に出力される。図１４は、本発明の一実施形態に係るＪＰＥＧ量子化テーブルの一例を示す図である。図１４（ａ）は、符号化パラメータ５１０６、５１０７として用いるＪＰＥＧの量子化テーブルの例である。この例では、システムのデフォルトの目標圧縮率を１／３２に設定しており、原画像に対して符号化後の符号データサイズが１／３２以下になるように符号メモリ５１０３の容量を確保している。
【００９９】
図１５は、本発明の一実施形態における２００パーセント拡大コピーの原稿とコピー出力の関係を示す図である。原稿５００１は、Ａ４原稿を表から見た図であり、スキャン時はこの原稿上面を下向きにプラテンガラス２１１に置き、原稿右上が原稿台突き当て位置に載置される。本実施形態では、原稿５００１を主走査、副走査ともに２００パーセント拡大して、Ａ４用紙にコピーする例であるため、出力画像領域に対応する原稿中の灰色部のみをスキャナで読み取り、２００パーセント拡大した画像を出力する。このときの出力用紙イメージがコピー出力５００３である。
【０１００】
すなわち、本実施形態に係る画像入出力システム１００では、プリンタ部３００から出力される復号化された画像データとリーダー部２００から入力される画像データとの倍率又は解像度の比率に基づいて制御装置１１０で当該画像データを符号化する際の符号化パラメータを決定することを特徴とする。
【０１０１】
また、本実施形態に係る画像入出力システム１００内の制御装置１１０では、プリンタ部３００から出力される復号化された画像データの出力形式に基づいて、リーダー部２００から入力される画像データの画像領域を決定し、リーダー部２００が、画像データのうち、決定された画像領域のみを入力することを特徴とする。
【０１０２】
図１６は、本発明の一実施形態における２００パーセント拡大コピー時の画像処理の概略を示すブロック図である。図１６は、Ａ４原稿を２００パーセント拡大してＡ４用紙へ出力する例を示している。本実施形態では、スキャン時の光学変倍は行わずに、ディジタル変倍処理による拡大を行っている。Ａ４サイズ原稿５２１４中、出力される灰色部分のみをスキャナ５２０１で読み取り、エンコーダ５２０２でＪＰＥＧ圧縮後、入力画像５２１５は、符号メモリ５２０３に格納される。
【０１０３】
その後、２００パーセント拡大処理を行うため、ＪＰＥＧ画像データ５２１５は、ＪＰＥＧデコーダ５２０４で復号され、ディジタル変倍ユニット５２０５へ入力され、２００パーセント拡大処理が行われる。拡大後のデータが再びエンコーダ５２０６へ入力され、ＪＰＥＧ圧縮されて符号メモリ５２０７へと格納される。そして、２００パーセント拡大されたＪＰＥＧ画像データ５２１６は、デコーダ５２０８を介して、プリンタ５２０９へ出力される。
【０１０４】
すなわち、本実施形態に係る画像入出力システム１００は、画像データを入力するリーダー部２００と、画像データを所定の符号化パラメータで符号化して符号化データを生成し、符号化データを復号化して復号画像データを生成する制御装置１１０と、復号画像データを出力するプリンタ部３００とを備える。そして、符号化データをシステム内のメモリ等に格納し、プリンタ部３００から出力される復号画像データの出力形式を指定し、指定された出力形式に基づいて、符号化パラメータを決定する。また、指定された出力形式に基づいて、メモリ等に格納された符号化データを変換し、変換された符号化データをシステム内のメモリ等に格納し、格納された符号化データを復号化する。
【０１０５】
また、本実施形態に係る画像入出力システムは、符号化データの変換に際して、メモリ等に格納された符号化データを復号化して一旦復号化データを生成し、その復号化データを出力形式に基づいて変換して、変換された復号化データを符号化して符号化データを生成することを特徴とする。
【０１０６】
次に、図１６に示すブロック図内のエンコーダ、デコーダに入力される符号化パラメータについて説明する。ここで、システムのデフォルトの目標圧縮率は１／３２とする。まず、エンコーダ５２０２に設定する符号化パラメータには、図１４（ｂ）の１／８圧縮の量子化テーブルを用いる。そして、スキャナからＡ４原稿５２１４の１／４サイズの領域（灰色部分）を等倍で読み込む。すなわち、メモリに取り込まれる画像サイズが、Ａ４に対して面積比で１／４となる。従って、目標圧縮率が１／８の量子化テーブルを用いることで、必要となるメモリ容量をＡ４サイズで１／３２圧縮した容量に収まるようにした。また、実際には１／８圧縮のため、通常の１／３２圧縮による場合よりも画像劣化を低く抑えることができる。
【０１０７】
すなわち、本実施形態に係る画像入出力システム１００では、出力形式に基づいて決定された圧縮率の量子化テーブルを用いて、画像データを圧縮符号化することを特徴とする。
【０１０８】
目標圧縮率１／８の量子化テーブルで圧縮されたＪＰＥＧデータを復号するための符号化パラメータ５２１１には、図１４（ｂ）の１／８圧縮の量子化テーブルを設定する。次に、２００パーセント変倍後の画像が入力されるエンコーダ５２０６に設定する符号化パラメータ５２１２には、図１４（ａ）の１／３２圧縮の量子化テーブルを用いる。これは、拡大後の画像は、画素数（面積）でＡ４サイズと等しくなるため、システムデフォルトの１／３２圧縮のパラメータを適用するためである。同様に、符号化パラメータ５２１３には、１／３２圧縮の量子化テーブルを用いる。
【０１０９】
すなわち、本実施形態に係る画像入出力システム１００では、入力される画像データの拡大率と出力される画像データの出力サイズとを出力形式として指定し、リーダー部２００が、出力サイズと拡大率に基づく画像データの所定領域のみを等倍率で入力し、制御装置１１０で拡大率に基づいて符号化パラメータを決定し、拡大率に基づいて符号化データを変換することを特徴とする。
【０１１０】
＜その他の実施形態＞
尚、本発明は、複数の機器（例えば、ホストコンピュータ、インタフェース機器、リーダ、プリンタ等）から構成されるシステムに適用しても、一つの機器からなる装置（例えば、複写機、ファクシミリ装置等）に適用してもよい。
【０１１１】
また、本発明の目的は、前述した実施形態の機能を実現するソフトウェアのプログラムコードを記録した記録媒体（または記憶媒体）を、システムあるいは装置に供給し、そのシステムあるいは装置のコンピュータ（またはＣＰＵやＭＰＵ）が記録媒体に格納されたプログラムコードを読み出し実行することによっても、達成されることは言うまでもない。この場合、記録媒体から読み出されたプログラムコード自体が前述した実施形態の機能を実現することになり、そのプログラムコードを記録した記録媒体は本発明を構成することになる。また、コンピュータが読み出したプログラムコードを実行することにより、前述した実施形態の機能が実現されるだけでなく、そのプログラムコードの指示に基づき、コンピュータ上で稼働しているオペレーティングシステム（ＯＳ）などが実際の処理の一部または全部を行い、その処理によって前述した実施形態の機能が実現される場合も含まれることは言うまでもない。
【０１１２】
さらに、記録媒体から読み出されたプログラムコードが、コンピュータに挿入された機能拡張カードやコンピュータに接続された機能拡張ユニットに備わるメモリに書き込まれた後、そのプログラムコードの指示に基づき、その機能拡張カードや機能拡張ユニットに備わるＣＰＵなどが実際の処理の一部または全部を行い、その処理によって前述した実施形態の機能が実現される場合も含まれることは言うまでもない。
【０１１３】
本発明を上記記録媒体に適用する場合、その記録媒体には、先に説明したフローチャートに対応するプログラムコードが格納されることになる。
【０１１４】
【発明の効果】
以上説明したように、本発明によれば、装置に搭載されているメモリ等を効率的に利用することにより、圧縮画像データの符号量を制御して、ディジタル変倍処理や解像度変換処理と画像圧縮で生じる画質の劣化を抑えることができる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る画像入出力システム全体の概略構成を示すブロック図である。
【図２】同実施形態における画像入出力システム１００内のリーダー部２００及びプリンタ部３００の概観図である。
【図３】本発明の一実施形態における制御装置１１０の詳細な構成を示すブロック図である。
【図４】本発明の一実施形態におけるリーダー画像処理回路部２２２の詳細な構成を示すブロック図である。
【図５】制御部１１０内のスキャナＩ／Ｆ１４０におけるＡＣＳカウント部６０３の詳細な構成を示すブロック図である。
【図６】制御部１１０内のスキャナＩ／Ｆ１４０における画像処理機能を担う部分の詳細な構成を示すブロック図である。
【図７】制御部１１０内のプリンタＩ／Ｆ１４５における画像処理機能を担う部分の詳細な構成を示すブロック図である。
【図８】制御部１１０内のグラフィックプロセッサ１３５の詳細な構成を示すブロック図である。
【図９】グラフィックプロセッサ１３５内の画像回転部８０１で転送される画像データを説明するための図である。
【図１０】グラフィックプロセッサ１３５内の画像回転部８０１における画像データの回転を説明するための図である。
【図１１】本発明の一実施形態における画像入出力システム１００でのＰＤＬ画像出力の手順を説明するためのフローチャートである。
【図１２】本発明の一実施形態に係る画像入出力システム１００におけるコピー画像出力の手順を説明するためのフローチャートである。
【図１３】等倍（１００パーセント）コピー時の画像処理の概略を示すブロック図である。
【図１４】本発明の一実施形態に係るＪＰＥＧ量子化テーブルの一例を示す図である。
【図１５】本発明の一実施形態における２００パーセント拡大コピー時の画像処理の概略を示すブロック図である。
【図１６】本発明の一実施形態における２００パーセント拡大コピー時の画像処理の概略を示すブロック図である。
【符号の説明】
１００　画像入出力システム
１１０　制御装置
１５０　操作部
２００　リーダー部
２１０　スキャナユニット
２５０　原稿給紙ユニット
３００　プリンタ部
３１０　マーキングユニット
３６０　給紙ユニット
３７０　排紙ユニット[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image processing method for compressing and expanding image data.
[0002]
[Prior art]
Conventionally, when handling color image data, the size of the data amount has been a problem. For example, for a binary image sufficient to represent a black-and-white image, a standard color image consisting of 8 bits each for RGB requires 24 times the data amount to represent an image of the same size. I will. Therefore, when storing image data in a storage device such as a hard disk or a memory, storing the same number of color image data requires a storage capacity that is 24 times that of a monochrome image.
[0003]
That is, simply handling a color image requires 24 times the memory capacity and hard disk capacity of handling a black and white image, which leads to a large increase in cost. Therefore, conventionally, a method has been employed in which compression processing is performed on image data to reduce the data capacity, thereby reducing the storage capacity required for a memory and a hard disk mounted on a device or the like, and suppressing an increase in cost.
[0004]
[Problems to be solved by the invention]
However, when an irreversible compression method such as JPEG is used in the compression processing of image data, there is a problem that image quality is deteriorated due to compression, and the image deterioration is remarkable while increasing the compression ratio. Also, when digital scaling processing is performed to perform image data enlargement / reduction processing, image deterioration due to data complementation errors occurs. Therefore, when irreversible compression is further performed on digitally scaled image data, there is a problem that the image quality is particularly greatly deteriorated as compared with the original image data.
[0005]
The present invention has been made in view of such circumstances, and controls the code amount of compressed image data to suppress the deterioration in image quality caused by digital scaling processing, resolution conversion processing, and image compression processing. It is an object of the present invention to provide an image processing method capable of performing the above.
[0006]
[Means for Solving the Problems]
In order to solve this problem, the present invention is characterized by the following configuration according to an embodiment described later.
[0007]
[Invention 1] Input means for inputting image data;
Encoding means for encoding the image data with a predetermined encoding parameter to generate encoded data;
Decoding means for decoding the encoded data to generate decoded image data;
Output means for outputting the decoded image data;
An image processing method for an image processing apparatus comprising:
A first storing step of storing the encoded data in a first storing unit;
A designation step of designating an output format of the decoded image data output from the output means;
An encoding parameter determining step of determining the encoding parameter based on the output format specified by the specifying step,
A conversion step of converting the encoded data stored in the first storage means based on the output format specified by the specification step;
A second storage step of storing the encoded data converted in the conversion step in a second storage unit;
A decoding step of decoding the encoded data stored in the second storage means;
An image processing method comprising:
[0008]
[Invention 2] The conversion step comprises:
A second decoding step of decoding the encoded data stored in the first storage means to generate second decoded data;
A second conversion step of converting the second decoded data decoded in the second decoding step based on the output format;
A second encoding step of encoding the second decoded data converted in the second conversion step to generate encoded data;
The image processing method according to the first aspect, comprising:
[0009]
[Invention 3] The invention 2 characterized in that the second conversion step performs image rotation, image scaling, color space conversion, or binarization processing to digitally convert the second decoded data. Image processing method.
[0010]
[Invention 4] The encoding parameter determining step determines the encoding parameter based on a ratio of a magnification or a resolution between the decoded image data output from the output unit and the image data input from the input unit. 4. The image processing method according to any one of inventions 1 to 3, wherein
[0011]
[Invention 5] The specifying step determines an image area of the image data input from the input means, based on the output format of the decoded image data output from the output means,
An input control step of inputting only a predetermined area determined by the specifying step from the image data to the input unit;
The image processing method according to any one of Inventions 1 to 4, further comprising:
[0012]
[Invention 6] The invention, further comprising an encoding control step of causing the encoding means to compress and encode the image data using a quantization table of a compression rate determined based on the output format. 6. The image processing method according to any one of 1 to 5.
[0013]
[Invention 7] The specifying step specifies an enlargement ratio of the image data and an output size of the decoded image data as an output format,
The input control step allows only the area of the image data based on the output size and the enlargement ratio to be input to the input unit at an equal magnification,
The encoding parameter determining step determines the encoding parameter based on the enlargement ratio,
The converting step converts the encoded data based on the enlargement ratio.
The image processing method according to the first aspect of the present invention.
[0014]
[Invention 8] Input means for inputting image data;
Encoding means for encoding the image data with a predetermined encoding parameter to generate encoded data;
Decoding means for decoding the encoded data to generate decoded image data;
Output means for outputting the decoded image data;
An image processing apparatus comprising:
First storage means for storing the encoded data;
Specifying means for specifying an output format of the decoded image data output from the output means;
An encoding parameter determining unit that determines the encoding parameter based on the output format specified by the specifying unit;
Conversion means for converting the encoded data stored in the first storage means, based on the output format specified by the specification means;
Second storage means for storing the encoded data converted by the conversion means;
Further comprising
The decoding means decodes the encoded data stored in the second storage means
An image processing apparatus comprising:
[0015]
[Invention 9] The conversion unit includes:
A second decoding unit that decodes the encoded data stored in the first storage unit to generate second decoded data;
Second conversion means for converting the second decoded data decoded by the second decoding means based on the output format;
A second encoding unit that encodes the second decoded data converted by the second conversion unit to generate encoded data;
The image processing apparatus according to the eighth aspect, comprising:
[0016]
[Invention 10] The invention according to Invention 9, wherein the second conversion means performs image rotation, image scaling, color space conversion, or binarization processing to digitally convert the second decoded data. Image processing device.
[0017]
[Invention 11] The encoding parameter determining unit determines the encoding parameter based on a ratio of a magnification or a resolution between the decoded image data output from the output unit and the image data input from the input unit. The image processing apparatus according to any one of Inventions 8 to 10, wherein
[0018]
[Invention 12] The specifying unit determines an image area of the image data input from the input unit based on the output format of the decoded image data output from the output unit,
The input unit inputs only the image area determined by the specifying unit out of the image data;
The image processing apparatus according to any one of Inventions 8 to 11, characterized in that:
[0019]
[Invention 13] The invention according to any one of Inventions 8 to 12, wherein the encoding means compresses and encodes the image data using a quantization table of a compression rate determined based on the output format. Item 2. The image processing device according to item 1.
[0020]
[Invention 14] The specifying means specifies an enlargement ratio of the image data and an output size of the decoded image data as an output format,
The input unit inputs only a predetermined area of the image data based on the output size and the enlargement ratio at an equal magnification,
The encoding parameter determining means determines the encoding parameter based on the enlargement ratio,
The conversion unit converts encoded data based on the enlargement ratio.
An image processing apparatus according to an eighth aspect of the present invention.
[0021]
[Invention 15] Input means for inputting image data,
Encoding means for encoding the image data with a predetermined encoding parameter to generate encoded data;
Decoding means for decoding the encoded data to generate decoded image data;
Output means for outputting the decoded image data;
Computer with
A first storage procedure for storing the encoded data in first storage means;
A specifying procedure for specifying an output format of the decoded image data output from the output unit;
Based on the output format specified by the specifying procedure, an encoding parameter determining step of determining the encoding parameter,
A conversion step of converting the encoded data stored in the first storage unit based on the output format specified by the specification step;
A second storage procedure for storing the coded data converted in the conversion procedure in a second storage unit;
A decoding procedure for decoding the encoded data stored in the second storage means;
The program to execute.
[0022]
[Invention 16] A computer-readable recording medium storing the program according to Invention 15.
[0023]
The reason for the configuration of the present invention will be apparent from the following description.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an image input / output system according to an embodiment of the present invention will be described with reference to the drawings.
[0025]
<Explanation of the whole image input / output system>
FIG. 1 is a block diagram showing a schematic configuration of an entire image input / output system according to an embodiment of the present invention. As shown in FIG. 1, in the image input / output system 100, a reader unit (image input device) 200 optically reads a document image and converts it into image data. The reader unit 200 includes a scanner unit 210 having a function of reading a document image and a document feeding unit 250 having a function of transporting document sheets.
[0026]
Further, the printer unit (image output device) 300 conveys the recording paper, prints image data thereon as a visible image, and discharges the recording paper outside the apparatus. The printer unit 300 includes a paper feeding unit 360 having a plurality of types of recording paper cassettes, a marking unit 310 having a function of transferring image data to recording paper and fixing the recording paper, and sorting and stapling the printed recording paper. And a paper discharge unit 370 having a function of outputting to the outside of the apparatus.
[0027]
The control device 110 is electrically connected to the reader unit 200 and the printer unit 300, and is further connected to host computers 401, 402 and the like via a network 400 such as a LAN. The control device 110 controls the reader unit 200 to read image data of a document, and controls the printer unit 300 to output the image data to recording paper to provide a copy function. The control device 110 converts the image data read from the reader unit 200 into code data and transmits the code data to the host computers 401 and 402 via the network 400, and receives the image data from the host computers 401 and 402 via the network 400. It provides a printer function of converting the converted code data into image data and outputting it to the printer unit 300.
[0028]
The operation unit 150 includes a liquid crystal touch panel, is connected to the control device 110, and provides a user interface (I / F) for operating the image input / output system 100.
[0029]
FIG. 2 is a schematic view of the reader unit 200 and the printer unit 300 in the image input / output system 100 according to the present embodiment. The document feeding unit 250 in the reader unit 200 feeds a document one by one onto the platen glass 211 in the order of the head, and discharges the document on the platen glass 211 after the reading operation of the document is completed. When the document is conveyed onto the platen glass 211, the lamp 212 is turned on, the movement of the optical unit 213 is started, and the document is exposed and scanned. The light reflected from the original at this time is guided to a CCD image sensor (hereinafter, referred to as “CCD”) 218 by mirrors 214, 215, 216 and a lens 217. Thus, the scanned image of the document is read by the CCD 218.
[0030]
Reference numeral 222 denotes a reader image processing circuit which performs predetermined processing on image data output from the CCD 218 and outputs the processed image data to the control device 110 via a scanner I / F 140 in the control device 110 described later. The details of the reader image processing circuit 222 and the control device 110 will be described later.
[0031]
Reference numeral 352 denotes a printer image processing circuit which outputs an image signal sent from the control device 110 to a laser driver via a printer I / F 145 in the control device 110 described later.
[0032]
A laser driver 317 of the printer unit 300 drives the laser light emitting units 313, 314, 315, and 316, and outputs laser light corresponding to image data output from the printer image processing unit 352 to the laser light emitting units 313, 314, 315. 316 are caused to emit light. The laser light is applied to the photosensitive drums 325, 326, 327, and 328 by mirrors 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, and 351. And 328, a latent image corresponding to the laser beam is formed. Reference numerals 321, 322, 323, and 324 denote developing units for developing a latent image using black (Bk), yellow (Y), cyan (C), and magenta (M) toners, respectively. The toner is transferred to a sheet and a full-color printout is performed.
[0033]
Paper fed from one of the paper cassettes 360 and 361 and the manual feed tray 362 at a timing synchronized with the start of laser light irradiation is adsorbed onto the transfer belt 334 via the registration rollers 333 and is conveyed. Then, the developer attached to the photosensitive drums 325, 326, 327, 328 is transferred to a recording sheet. The recording paper on which the developer is loaded is conveyed to the fixing unit 335, and the developer is fixed on the recording paper by the heat and pressure of the fixing unit 335. The recording paper that has passed through the fixing unit 335 is discharged by a discharge roller 336, and a discharge unit 370 sorts the recording paper by bundling the discharged recording paper and staples the sorted recording paper.
[0034]
When double-sided printing is set, the recording paper is conveyed to the discharge roller 336, the rotation direction of the discharge roller 336 is reversed, and the recording paper is guided to the re-feed conveyance path 338 by the flapper 337. The recording sheet guided to the re-feeding conveyance path 338 is fed to the transfer belt 334 at the timing described above.
[0035]
<Description of Reader Image Processing Circuit 222>
FIG. 4 is a block diagram illustrating a detailed configuration of the reader image processing circuit unit 222 according to the embodiment of the present invention. In the reader image processing circuit 222, the original on the platen glass 211 is read by the CCD 218 and converted into an electric signal. In the case of a color sensor, the CCD 218 in the present embodiment is a three-line CCD, in which an RGB color filter is inlined in RGB order on a one-line CCD, and an R filter, a G filter, and a B filter, respectively. It may be arranged for each CCD. Also, the filter may be on-chip, or the filter may have a different structure from the CCD.
[0036]
When the electric signal (analog image signal) is input to the reader image processing circuit unit 222, first, the clamp & Amp. The sample / hold (S / H) is performed by the & S / H & A / D unit 401, the dark level of the analog image signal is clamped to the reference potential, and is amplified to a predetermined amount (the above processing order is not limited to the writing order). The signal is D-converted and converted into, for example, a digital signal of 8 bits for each of RGB. Then, the RGB signals are subjected to shading correction and black correction by the shading unit 402, and then output to the control device 110.
[0037]
<Description of control device 110>
FIG. 3 is a block diagram illustrating a detailed configuration of the control device 110 according to the embodiment of the present invention. The main controller 111 mainly includes a CPU 112, a bus controller 113, and various I / F controller circuits.
[0038]
The CPU 112 and the bus controller 113 control the operation of the entire control device 110. The CPU 112 operates based on a program read from the ROM 114 via the ROM I / F 115. The operation of interpreting the PDL (page description language) code data received from the host computers 401 and 402 and developing it into raster image data is also described in this program and processed by software. The bus controller 113 controls data transfer input / output from each I / F, and performs arbitration at the time of bus contention and controls DMA data transfer.
[0039]
The DRAM 116 is connected to the main controller 111 by a DRAM I / F 117, and is used as a work area for the operation of the CPU 112 and an area for storing image data.
[0040]
The codec 118 compresses the raster image data stored in the DRAM 116 using a method such as MH / MR / MMR / JBIG / JPEG. Conversely, the Codec 118 expands the compressed and stored code data into raster image data. The SRAM 119 is used as a temporary work area of the Codec 118. The Codec 118 is connected to the main controller 111 via the I / F 120, and data transfer to and from the DRAM 116 is controlled by the bus controller 113 and DMA-transferred.
[0041]
The graphic processor 135 performs image rotation, image scaling, color space conversion, and binarization processing on the raster image data stored in the DRAM 116. The SRAM 136 is used as a temporary work area of the graphic processor 135. The graphic processor 135 is connected to the main controller 111 via the I / F 137, and data transfer to and from the DRAM 116 is controlled by the bus controller 113 and DMA-transferred.
[0042]
A network controller (Network Controller) 121 is connected to the main controller 111 by an I / F 123, and is connected to an external network by a connector 122. An example of a network is generally Ethernet (registered trademark).
[0043]
An expansion connector 124 for connecting an expansion board and an I / O control unit 126 are connected to the general-purpose high-speed bus 125. One example of a general-purpose high-speed bus is a PCI bus.
[0044]
The I / O control unit 126 includes two channels of a serial communication controller 127 for transmitting and receiving control commands to and from each of the CPUs of the reader unit 200 and the printer unit 300. The I / O bus 128 provides an external I / F circuit. (Scanner I / F 140, printer I / F 145).
[0045]
The panel I / F 132 is connected to the LCD controller 131 and has an I / F for displaying on a liquid crystal screen on the operation unit 150 shown in FIG. 1 and a key input I / F for inputting hard keys and touch panel keys. F130.
[0046]
The operation unit 150 illustrated in FIG. 1 includes a liquid crystal display unit, a touch panel input device attached on the liquid crystal display unit, and a plurality of hard keys. A signal input by a touch panel or a hard key is transmitted to the CPU 112 via the panel I / F 132 described above. The liquid crystal display unit of the operation unit 150 displays the image data sent from the panel I / F 132. In addition, the liquid crystal display displays a function display, image data, and the like relating to the operation of the image input / output system.
[0047]
The real-time clock module 133 updates and saves the date and time managed in the device, and is backed up by the backup battery 134. The E-IDE connector 161 is for connecting an external storage device. In the present embodiment, a hard disk (HD) drive 160 is connected via the E-IDE connector 161 to perform operations of storing image data in the hard disk (HD) 162 and reading image data from the hard disk 162.
[0048]
The connectors 142 and 147 are connected to the reader unit 200 and the printer unit 300, respectively. The connector 142 connects to the asynchronous serial I / F 143 and the video I / F 144, and the connector 147 connects to the asynchronous serial I / F 148 and the video I / F 149.
[0049]
The scanner I / F 140 is connected to the reader unit 200 via the connector 142, and is connected to the main controller 111 via the scanner bus 141, and has a function of performing predetermined processing on an image received from the reader unit 200. Have. The scanner I / F 140 also has a function of outputting a control signal generated based on the video control signal sent from the reader unit 200 to the scanner bus 141. Data transfer from the scanner bus 141 to the DRAM 116 is controlled by the bus controller 113.
[0050]
The printer I / F 145 is connected to the printer unit 300 via the connector 147, and is connected to the main controller 111 via the printer bus 146. The printer I / F 145 has a function of performing predetermined processing on the image data output from the main controller 111 and outputting the processed data to the printer unit 300. Further, the printer I / F 145 has a function of outputting a control signal generated based on the video control signal transmitted from the printer unit 300 to the printer bus 146.
[0051]
The transfer of the raster image data developed on the DRAM 116 to the printer unit 300 is controlled by the bus controller 113 and is DMA-transferred to the printer unit 300 via the printer bus 146 and the video I / F 149.
[0052]
<Description of Image Processing Function of Scanner I / F>
Here, a detailed description will be given of a portion that performs an image processing function in the scanner I / F 140. FIG. 6 is a block diagram illustrating a detailed configuration of a portion that performs an image processing function in the scanner I / F 140 in the control unit 110. An image signal is sent from the reader unit 200 to the scanner I / F 140 via the connector 142. On the other hand, in the connection & MTF correction unit 601 in the scanner I / F 140, when the CCD 218 is a three-line CCD, the connection processing differs in the reading position between the lines, so the delay amount for each line is adjusted according to the reading speed. Then, the signal timing is corrected so that the reading positions of the three lines are the same, and the MTF correction corrects the change because the reading MTF changes depending on the reading speed.
[0053]
The digital signal whose read position timing has been corrected corrects the spectral characteristics of the CCD 218 and the spectral characteristics of the lamp 212 and the mirrors 214, 215, 216 by the input masking unit 602. The output of the input masking unit 602 is sent to an ACS (auto color select) counting unit 603 and the main controller 111.
[0054]
<Description of ACS counting section 603>
FIG. 5 is a block diagram illustrating a detailed configuration of the ACS counting unit 603 in the scanner I / F 140. ACS determines whether a document is color or black and white. That is, color saturation is determined for each pixel, and color determination is performed based on how many pixels above a certain threshold value exist. However, even for a black-and-white document, there are many color pixels around the edge when viewed microscopically due to the influence of MTF and the like, and it is difficult to simply perform the ACS determination in pixel units. Various methods are provided as the ACS method. In this embodiment, a general ACS method will be described.
[0055]
As described above, even in a black-and-white image, since there are a large number of color pixels when viewed microscopically, it is necessary to determine whether or not the pixel is really a color pixel based on information on color pixels around the target pixel. The filter 501 is a filter for determining whether or not a pixel is a color pixel. In order to refer to a peripheral pixel with respect to a target pixel, a FIFO (First In) is used.
First Out: First Out First Out).
[0056]
Reference numeral 502 denotes an area detection circuit that generates an area signal 505 to be subjected to ACS based on the values set in the registers 507 to 510 set by the main controller 111 and the video control signal 512 sent from the reader unit 200. . Reference numeral 503 denotes a color determination unit for determining whether the target pixel is a color pixel or a black-and-white pixel based on the region signal 505 to which the ACS is applied, by referring to peripheral pixels in the memory in the filter 501 for the target pixel. . A counter 504 counts the number of color determination signals output by the color determination unit 503.
[0057]
The main controller 111 determines an area to be subjected to the ACS with respect to the read range, and sets the area in the registers 507 to 510. In this embodiment, a configuration is adopted in which the range is determined independently of the original. Further, the main controller 111 compares the value of a counter for counting the number of color determination signals in the area to be subjected to the ACS with a predetermined threshold value, and determines whether the original is color or monochrome.
[0058]
In the registers 507 to 510, the position at which the color determination unit 503 starts the determination and the position at which the determination ends are determined for each of the main scanning direction and the sub-scanning direction based on the video control signal 512 sent from the reader unit 200. Set it. In this embodiment, the size of each document is set to be about 10 mm smaller than the actual size of the document.
[0059]
<Description of Image Processing Function of Printer I / F 145>
FIG. 7 is a block diagram illustrating a detailed configuration of a part that performs an image processing function in the printer I / F 145 in the control unit 110.
[0060]
An image signal sent from the main controller 111 via the printer bus 146 is first input to a LOG conversion unit 701 in the printer I / F. The LOG conversion unit 701 converts the RGB signals into CMY signals by LOG conversion. Next, the moiré is removed by the moiré removing unit 702. A UCR & masking unit 703 generates a CMYK signal from the CMY signal subjected to the moiré removal processing by the UCR processing, and corrects the CMYK signal to a signal which has been output from the printer by the masking processing. The signal processed by the UCR & masking unit 703 is subjected to density adjustment by the γ correction unit 704 and then subjected to smoothing or edge processing by the filter unit 705. Through these processes, an image is sent to the printer unit 300 via the connector 147.
[0061]
<Description of Graphic Processor 135>
FIG. 8 is a block diagram showing a detailed configuration of the graphic processor 135 in the control unit 110. The graphic processor 135 has modules for performing image rotation, image scaling, color space conversion, and binarization processing. The SRAM 136 is used as a temporary work area of each module of the graphic processor 135. It is assumed that a work area is statically allocated to each module in advance so that the work area of the SRAM 136 used by each module does not conflict. The graphic processor 135 is connected to the main controller 111 via the I / F 137, and data transfer to and from the DRAM 116 is controlled by the bus controller 113 and DMA-transferred.
[0062]
The bus controller 113 performs control for setting a mode and the like for each module of the graphic processor 135 and timing control for transferring image data to each module.
[0063]
<Description of Image Rotation Unit 801>
Next, processing in the image rotation unit 801 in the graphic processor 135 will be described. First, settings for image rotation control are made from the CPU 112 to the bus controller 113 via the I / F 137. With this setting, the bus controller 113 performs settings necessary for image rotation (for example, image size, rotation direction, angle, and the like) for the image rotation unit 801. After performing the necessary settings, the CPU 112 again permits the bus controller 113 to transfer image data. According to this permission, the bus controller 113 starts transfer of image data from the DRAM 116 or a device connected via each I / F.
[0064]
FIG. 9 is a diagram for explaining image data transferred by the image rotation unit 801 in the graphic processor 135. Here, the image size to be rotated is set to 32 pixels × 32 lines, and when transferring the image data on the image bus, the image transfer is performed in units of 24 bytes (8 bits each for RGB, one pixel). I do.
[0065]
As described above, in order to obtain an image of 32 pixels × 32 lines, it is necessary to perform the above unit data transfer 32 × 32 times, and it is necessary to transfer image data from discontinuous addresses.
[0066]
The image data transferred by the discontinuous addressing is written to the SRAM 136 such that the image data is rotated at a desired angle at the time of reading. FIG. 10 is a diagram for explaining rotation of image data in the image rotation unit 801 in the graphic processor 135. For example, if the rotation is 90 degrees counterclockwise, the image data to be transferred is written in the Y direction as shown in FIG. Then, by reading in the X direction at the time of reading, the image is rotated.
[0067]
After the image rotation of 32 pixels × 32 lines (writing to the SRAM 136) is completed, the image rotating unit 801 reads the image data from the SRAM 136 by the above-described reading method, and transfers the image to the bus controller 113.
[0068]
The bus controller 113 that has received the rotated image data transfers the data to the DRAM 116 or each device on the I / F with continuous addressing. The above-described series of processing is repeated until there is no processing request from the CPU 112 (until the processing of the required number of pages is completed).
[0069]
<Description of the image scaling unit 802>
Next, a processing procedure in the image scaling unit 802 in the graphic processor 135 will be described. First, the CPU 112 makes settings for image scaling control from the CPU 112 to the bus controller 113 via the I / F 137. With this setting, the bus controller 113 performs settings necessary for image scaling (the scaling ratio in the main scanning direction, the scaling ratio in the sub-scanning direction, the image size after scaling, etc.) for the image scaling unit 802. After performing the necessary settings, the CPU 112 again permits the bus controller 113 to transfer image data. According to this permission, the bus controller 113 starts transfer of image data from the DRAM 116 or a device connected via each I / F.
[0070]
The image scaling unit 802 stores the received image data in the temporary SRAM 136, and uses the image data as an input buffer. The stored data has the required number of pixels and the number of lines according to the scaling ratio of main scanning and sub scanning. The image is enlarged or reduced by performing an interpolation process corresponding to, thereby performing a scaling process. The data after scaling is written back to the SRAM 136 again, and the image scaling unit 802 reads the image data from the SRAM 136 using this as an output buffer, and transfers it to the bus controller 113. The bus controller 113 receiving the image data subjected to the scaling process transfers the data to the DRAM 116 or each device on the I / F.
[0071]
<Description of Color Space Conversion Unit 803>
Next, a processing procedure in the color space conversion unit 803 will be described. Settings for color space conversion control are made from the CPU 112 to the bus controller 113 via the I / F 137. With these settings, the bus controller 113 performs settings (coefficients of matrix operation, table values of the LUT 804, etc., described later) necessary for the color space conversion processing on the color space conversion unit 803 and the LUT (look-up table) 804.
[0072]
After performing the necessary settings, the CPU 112 again permits the bus controller 113 to transfer image data. According to this permission, the bus controller 113 starts transfer of image data from the DRAM 116 or a device connected via each I / F.
[0073]
The color space conversion unit 803 performs a 3 × 3 matrix operation represented by the following equation for each pixel of the received image data.
[0074]
(Equation 1)

[0075]
In the above equation, R, G, B are inputs, X, Y, Z are outputs, a11, a12, a13, a21, a22, a23, a31, a32, a33, b1, b2, b3, c1, c2, c3 are Each is a coefficient.
[0076]
Various color space conversions, such as conversion from the RGB color space to the Yuv color space, can be performed by the above equation.
[0077]
Next, conversion by the LUT 804 is performed on the data after the matrix operation. As a result, nonlinear conversion can be performed. By setting a through table, LUT conversion can not be performed substantially. After that, the color space conversion unit 803 transfers the image data subjected to the color space conversion processing to the bus controller 113. The bus controller 113 that receives the image data subjected to the color space conversion process transfers the data to the DRAM 116 or each device on the I / F.
[0078]
<Description of Image Binarization Unit 805>
Next, a processing procedure in the image binarization unit 805 will be described. Via the I / F 137, the CPU 112 makes settings for binarization control in the bus controller 113. With this setting, the bus controller 113 performs settings (various parameters and the like according to the conversion method) necessary for the binarization processing on the image binarization unit 805. After performing the necessary settings, the CPU 112 again permits the bus controller 113 to transfer image data. In accordance with this permission, the bus controller 113 starts transferring image data from the connected device via the DRAM 116 or each I / F.
[0079]
The image binarization unit 805 performs a binarization process on the received image data. In the present embodiment, the image data is simply binarized by comparing the image data with a predetermined threshold value as a binarization method. Note that any method such as a dither method, an error diffusion method, or an improved error diffusion method may be used.
[0080]
After that, the image binarization unit 805 transfers the image data subjected to the binarization processing to the bus controller 113. The bus controller 113 receiving the binarized image data transfers the data to the DRAM 116 or each device on the I / F.
[0081]
<Description of sequence when outputting PDL image>
FIG. 11 is a flowchart illustrating a procedure of outputting a PDL image in the image input / output system 100 according to the embodiment of the present invention. When outputting a PDL image, first, the user sets print settings for the PDL image output job on the PC 401 (step S111). Here, the print setting contents include the number of copies, paper size, one-sided / two-sided, page output order, sort output, and whether or not stapling is performed.
[0082]
Next, a print instruction is given on the PC 401, and at the same time, driver software installed on the PC 401 converts code data on the PC 401 to be printed into so-called PDL data, and sets the print setting parameters set in step S111. At the same time, PDL data is transferred to the control device 110 of the image input / output system 100 via the network 400 (Step S112).
[0083]
Further, the CPU 112 of the main controller 111 of the control device 110 develops (rasterizes) the PDL data transferred via the connector 122 and the network controller 121 into image data based on the print setting parameters (step S113). The development of the image data is performed on the DRAM 116. When the development of the image data is completed, the process proceeds to step S114.
[0084]
In step S114, the main controller 111 transfers the image data developed on the DRAM 116 to the graphic processor 135.
[0085]
Next, the graphic processor 135 performs image processing independently of the print setting parameters (step S115). That is, in the image input / output system 100 according to the present embodiment, the image conversion processing by the graphic processor 135 performs image rotation, image scaling, color space conversion, or binarization processing to digitally convert the decoded data. It is characterized by.
For example, if the paper size specified by the print setting parameters is A4, but the paper supply unit 360 of the printer unit 300 has only A4R paper, the graphic processor 135 rotates the image by 90 degrees. It is possible to output an image according to the output paper. When the image processing of the image data is completed, the process proceeds to step S116.
[0086]
In step S116, the graphic processor 135 transfers the image data after the image processing to the main controller 111. The main controller 111 stores the transferred image data on the DRAM 116.
[0087]
Next, the main controller 111 transfers the image data on the DRAM 116 to the printer unit 300 at appropriate timing while controlling the printer unit 300 via the printer I / F 145 and the connector 147 (step S117).
[0088]
Then, the control device 110 controls the printer unit 300 to print out the image data (step S118). When the transfer of the image data is completed (that is, when the PDL job ends), the print output ends.
[0089]
<Sequence when outputting a copy image>
FIG. 12 is a flowchart illustrating a procedure of outputting a copy image in the image input / output system 100 according to the embodiment of the present invention. When outputting a copy image, the user performs copy setting of the copy image output job on the operation unit 150 (step S121). The copy setting contents include the number of copies, paper size, one-sided / two-sided, enlargement / reduction ratio, sort output, and whether or not stapling is performed.
[0090]
Next, when a copy start instruction is given on the operation unit 150, the main controller 111 of the control device 110 controls the reader unit 200 via the scanner I / F 140 and the connector 142 to read the image data of the document. First, the document feeding unit 250 feeds the placed documents one by one onto the platen glass 211, and at the same time, detects the size of the document. The image data is read by exposing and scanning the document based on the detected size of the document. The read image data is stored on the DRAM 116 (Step S122).
[0091]
In the conventional copier, the magnification in the sub-scanning direction is realized by changing the moving speed of the optical unit 213 according to the enlargement / reduction ratio in the copy setting, that is, according to the magnification in the sub-scanning direction. I was However, in this embodiment, regardless of the setting of the enlargement / reduction ratio in the copy setting, the image data is always read at the same magnification (100%), and the scaling process will be described later in both the main scanning direction and the sub-scanning direction. It is assumed that the processing is performed by the graphic processor 135.
[0092]
Next, the main controller 111 transfers the image data on the DRAM 116 to the graphic processor 135 (Step S123).
[0093]
Further, the graphic processor 135 performs image processing based on the copy setting parameters (Step S124). For example, when the enlargement of 400% is set, the image scaling unit 802 which is a module in the graphic processor 135 performs scaling processing in both the main scanning direction and the sub-scanning direction. When the image processing of the image data is completed, the process proceeds to step S125.
[0094]
In step S125, the graphic processor 135 transfers the image data after the image processing to the main controller 111. The main controller 111 stores the transferred image data on the DRAM 116.
[0095]
Further, the main controller 111 transfers the image data on the DRAM 116 to the printer unit 300 at an appropriate timing while controlling the printer unit 300 via the printer I / F 145 and the connector 147 (step S126).
[0096]
Then, the control device 110 controls the printer unit 300 to print out the image data (step S127). When the transfer of the image data is completed (that is, when the copy job ends), the print output ends.
[0097]
<Explanation of determination of reading area and selection of encoding parameter according to magnification ratio>
FIG. 13 is a block diagram showing an outline of image processing at the time of copying at the same size (100%). Image data obtained by reading an A4 size original 5108 by the scanner 5101 is input to a JPEG encoder 5102 and subjected to real-time compression. When encoding is performed by the encoder 5102, an encoding parameter 5106 corresponding to a target compression ratio is input to the encoder 5102. The compressed code data 5109 is stored in the code memory 5103.
[0098]
Next, the code data 5109 is input to the JPEG decoder 5104, and the decoded image data 5110 is input to the printer 5105, and is output on A4 paper. FIG. 14 is a diagram illustrating an example of a JPEG quantization table according to an embodiment of the present invention. FIG. 14A is an example of a JPEG quantization table used as the encoding parameters 5106 and 5107. In this example, the default target compression ratio of the system is set to 1/32, and the capacity of the code memory 5103 is secured so that the code data size of the original image after encoding becomes 1/32 or less. ing.
[0099]
FIG. 15 is a diagram illustrating a relationship between a manuscript of 200% enlarged copy and a copy output according to an embodiment of the present invention. A document 5001 is a view of an A4 document viewed from the front. During scanning, the upper surface of the document is placed on the platen glass 211 with the upper surface of the document facing downward, and the upper right of the document is placed at the platen abutting position. In this embodiment, since the original 5001 is enlarged by 200% in both the main scanning and the sub-scanning and is copied on A4 paper, only the gray portion in the original corresponding to the output image area is read by the scanner and enlarged by 200%. And output the resulting image. The output paper image at this time is the copy output 5003.
[0100]
That is, in the image input / output system 100 according to the present embodiment, the control device 110 is controlled based on the magnification or resolution ratio between the decoded image data output from the printer unit 300 and the image data input from the reader unit 200. Is used to determine an encoding parameter for encoding the image data.
[0101]
In the control device 110 in the image input / output system 100 according to the present embodiment, based on the output format of the decoded image data output from the printer unit 300, the image of the image data input from the reader unit 200 is output. The region is determined, and the reader unit 200 inputs only the determined image region of the image data.
[0102]
FIG. 16 is a block diagram illustrating an outline of image processing at the time of 200% enlarged copy according to an embodiment of the present invention. FIG. 16 shows an example in which an A4 document is enlarged by 200% and output on A4 paper. In the present embodiment, enlargement is performed by digital scaling without performing optical scaling during scanning. In the A4 size document 5214, only the gray portion to be output is read by the scanner 5201, JPEG-compressed by the encoder 5202, and the input image 5215 is stored in the code memory 5203.
[0103]
Thereafter, in order to perform the 200% enlargement processing, the JPEG image data 5215 is decoded by the JPEG decoder 5204 and input to the digital scaling unit 5205, where the 200% enlargement processing is performed. The data after the enlargement is input to the encoder 5206 again, JPEG-compressed, and stored in the code memory 5207. The JPEG image data 5216 enlarged by 200% is output to the printer 5209 via the decoder 5208.
[0104]
That is, the image input / output system 100 according to the present embodiment generates the encoded data by encoding the image data with a predetermined encoding parameter and the reader unit 200 that inputs the image data, and decodes the encoded data. The control device 110 includes a control device 110 that generates decoded image data and a printer unit 300 that outputs the decoded image data. Then, the encoded data is stored in a memory or the like in the system, the output format of the decoded image data output from the printer unit 300 is designated, and the encoding parameter is determined based on the designated output format. Also, based on the specified output format, the coded data stored in the memory or the like is converted, the converted coded data is stored in a memory or the like in the system, and the stored coded data is decoded. .
[0105]
Further, when converting the encoded data, the image input / output system according to the present embodiment decodes the encoded data stored in the memory or the like to temporarily generate the decoded data, and converts the decoded data based on the output format. And converting the decoded data to generate encoded data.
[0106]
Next, encoding parameters input to the encoder and decoder in the block diagram shown in FIG. 16 will be described. Here, the default target compression ratio of the system is 1/32. First, a quantization table of 1/8 compression shown in FIG. 14B is used as an encoding parameter set in the encoder 5202. Then, a 1/4 size area (gray part) of the A4 document 5214 is read from the scanner at the same magnification. That is, the size of the image taken into the memory is 1/4 of the area ratio of A4. Therefore, by using a quantization table with a target compression ratio of 1/8, the required memory capacity is set to be within the capacity of 1/32 compression of the A4 size. Further, since the compression is actually 1/8, image deterioration can be suppressed lower than in the case of normal 1/32 compression.
[0107]
That is, the image input / output system 100 according to the present embodiment is characterized in that image data is compression-encoded using a quantization table of a compression ratio determined based on an output format.
[0108]
As the encoding parameter 5211 for decoding the JPEG data compressed by the quantization table having the target compression rate of 1/8, the quantization table of 1/8 compression shown in FIG. 14B is set. Next, a quantization table of 1/32 compression in FIG. 14A is used as an encoding parameter 5212 to be set in the encoder 5206 to which the image after scaling by 200% is input. This is because the enlarged image is equal to the A4 size in terms of the number of pixels (area), so that the system default 1/32 compression parameter is applied. Similarly, a 1/32 compression quantization table is used as the encoding parameter 5213.
[0109]
That is, in the image input / output system 100 according to the present embodiment, the enlargement ratio of the input image data and the output size of the output image data are specified as the output format, and the reader unit 200 specifies the output size and the enlargement ratio. Only a predetermined area of image data based on the input data is input at the same magnification, the control device 110 determines an encoding parameter based on the enlargement ratio, and converts the encoded data based on the enlargement ratio.
[0110]
<Other embodiments>
Note that the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but a device including one device (for example, a copying machine, a facsimile machine, etc.). May be applied.
[0111]
Further, an object of the present invention is to supply a recording medium (or a storage medium) recording a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or a CPU or a CPU) of the system or the apparatus. Needless to say, the present invention can also be achieved by the MPU) reading and executing the program code stored in the recording medium. In this case, the program code itself read from the recording medium implements the functions of the above-described embodiment, and the recording medium on which the program code is recorded constitutes the present invention. When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. It goes without saying that a part or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.
[0112]
Further, after the program code read from the recording medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.
[0113]
When the present invention is applied to the recording medium, the recording medium stores program codes corresponding to the flowcharts described above.
[0114]
【The invention's effect】
As described above, according to the present invention, the code amount of compressed image data is controlled by efficiently using a memory or the like mounted on the device, and digital scaling processing and resolution conversion processing are performed. Deterioration of image quality caused by compression can be suppressed.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a schematic configuration of an entire image input / output system according to an embodiment of the present invention.
FIG. 2 is a schematic view of a reader unit 200 and a printer unit 300 in the image input / output system 100 according to the embodiment.
FIG. 3 is a block diagram illustrating a detailed configuration of a control device 110 according to an embodiment of the present invention.
FIG. 4 is a block diagram illustrating a detailed configuration of a reader image processing circuit unit 222 according to an embodiment of the present invention.
FIG. 5 is a block diagram showing a detailed configuration of an ACS counting unit 603 in the scanner I / F 140 in the control unit 110.
FIG. 6 is a block diagram showing a detailed configuration of a portion having an image processing function in a scanner I / F 140 in a control unit 110.
FIG. 7 is a block diagram illustrating a detailed configuration of a part that performs an image processing function in a printer I / F 145 in the control unit 110.
FIG. 8 is a block diagram showing a detailed configuration of a graphic processor 135 in the control unit 110.
FIG. 9 is a diagram for describing image data transferred by an image rotation unit 801 in the graphic processor 135.
FIG. 10 is a diagram for explaining rotation of image data in an image rotation unit 801 in the graphic processor 135.
FIG. 11 is a flowchart illustrating a procedure of outputting a PDL image in the image input / output system 100 according to the embodiment of the present invention.
FIG. 12 is a flowchart illustrating a procedure of outputting a copy image in the image input / output system 100 according to an embodiment of the present invention.
FIG. 13 is a block diagram illustrating an outline of image processing during 1: 1 (100%) copy.
FIG. 14 is a diagram illustrating an example of a JPEG quantization table according to an embodiment of the present invention.
FIG. 15 is a block diagram illustrating an outline of image processing at the time of 200% enlarged copy according to an embodiment of the present invention.
FIG. 16 is a block diagram illustrating an outline of image processing at the time of 200% enlarged copy according to an embodiment of the present invention.
[Explanation of symbols]
100 image input / output system
110 control device
150 Operation unit
200 Leader Club
210 Scanner unit
250 Document feeding unit
300 Printer section
310 Marking unit
360 paper feed unit
370 paper ejection unit

Claims (1)

Input means for inputting image data;
Encoding means for encoding the image data with a predetermined encoding parameter to generate encoded data;
Decoding means for decoding the encoded data to generate decoded image data;
Output means for outputting the decoded image data, the image processing method of an image processing apparatus comprising:
A first storing step of storing the encoded data in a first storing unit;
A designation step of designating an output format of the decoded image data output from the output means;
An encoding parameter determining step of determining the encoding parameter based on the output format specified by the specifying step,
A conversion step of converting the encoded data stored in the first storage means based on the output format specified by the specification step;
A second storage step of storing the encoded data converted in the conversion step in a second storage unit;
A decoding step of decoding the encoded data stored in the second storage means.

Images