JP2005027037A - Format conversion method and image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a format conversion method and an image processing apparatus for creating image data with optimum gradation and compression without a user carrying out troublesome works. <P>SOLUTION: An image area separation (character discrimination) section of a scanner I/F 140 discriminates whether or not the image data of a read original include character parts and a color discrimination section discriminates whether or not the image data include a chromatic color to extract the feature of the original. A Graphic Processor 135 converts the image format of the image data in response to the feature of the original and the HD 162 stores the converted image data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００６４】
上記式において、Ｒ、Ｇ、Ｂが入力、Ｘ、Ｙ、Ｚが出力、ａ_１１、ａ_１２、ａ_１３、ａ_２１、ａ_２２、ａ_２３、ａ_３１、ａ_３２、ａ_３３、ｂ_１、ｂ_２、ｂ_３、ｃ_１、ｃ_２、ｃ_３がそれぞれ係数である。
【００６５】
上記式の演算によって、例えばＲＧＢ色空間からＹｕｖ色空間への変換など、各種の色空間変換を行うことができる。
【００６６】
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。これにより、非線形の変換も行うことができる。当然、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しても良い。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。
【００６７】
上述のように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もしくはＩ／Ｆ上の各デバイスにデータを転送する。
【００６８】
＜画像二値化部の説明＞
次に、画像二値化部８０５における処理手順を示す。ＣＰＵ１１２はバスコントローラ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Ｉ／Ｆ１３７を介して画像二値化部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もしくは各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。
【００６９】
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。尚、本実施形態では、二値化の手法としては、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。もちろん、ディザ法、誤差拡散法、誤差拡散法又は改良したものなど、何れの手法によってもかまわない。
【００７０】
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もしくはＩ／Ｆ上の各デバイスにデータを転送する。
【００７１】
＜ＰＤＬ画像出力時のシーケンス＞
図１１は、本実施形態におけるＰＤＬ画像出力の手順を示すフローチャートである。ＰＤＬ画像を出力する場合、まず、ステップＳ１１０１において、ＰＣ４０１上でユーザーが当該ＰＤＬ画像出力ジョブのプリント設定を行う。プリント設定の内容としては、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。
【００７２】
次に、ステップＳ１１０２において、ＰＣ４０１上で印刷指示が与えられると、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データに変換する。そして、そのＰＤＬデータをステップＳ１１０１で設定したプリント設定パラメータと共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を介して転送する。
【００７３】
次に、ステップＳ１１０３において、制御装置１１０内のメインコントローラ１１１のＣＰＵ１１２がコネクタ１２２及びＮｅｔｗｏｒｋＣｏｎｔｒｏｌｌｅｒ１２１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。尚、画像データの展開は、ＤＲＡＭ１１６上に行われる。この画像データの展開が完了するとステップＳ１１０４へ進み、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Ｇｒａｐｈｉｃ Ｐｒｏｃｅｓｓｏｒ１３５へ転送する。
【００７４】
次に、ステップＳ１１０５において、Ｇｒａｐｈｉｃ Ｐｒｏｃｅｓｓｏｒ１３５がプリント設定パラメータとは独立に画像処理を行う。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、Ｇｒａｐｈｉｃ Ｐｒｏｃｅｓｓｏｒ１３５で画像を９０度回転することにより、出力用紙にあわせた画像出力を行うことができる。この画像データの画像処理が完了するとステップＳ１１０６へ進み、Ｇｒａｐｈｉｃ Ｐｒｏｃｅｓｓｏｒ１３５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。そして、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。
【００７５】
次に、ステップＳ１１０７において、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へ転送する。
【００７６】
そして、ステップＳ１１０８において、制御装置１１０はプリンタ部３００を制御して画像データをプリント出力する。この画像データの転送が完了すると、即ち、このＰＤＬジョブが終了すると、プリント出力を終了する。
【００７７】
＜コピー画像出力時のシーケンス＞
図１２は、本実施形態におけるコピー画像出力の手順を示すフローチャートである。コピー画像を出力する場合、まず、ステップＳ１２０１において、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。コピー設定の内容としては、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。
【００７８】
次に、ステップＳ１２０２において、操作部１５０からコピー開始指示が与えられると、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。ここでは、原稿給紙ユニット２５０が載置された原稿を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、画像データが読み取られる。この読み取られた画像データはＤＲＡＭ１１６上に記憶される。従来のコピー機では、コピー設定の拡大／縮小率の設定に応じて、即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。
【００７９】
しかしながら、本実施形態では、コピー設定の拡大／縮小率の設定にかかわらず、必ず等倍（１００％）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、Ｇｒａｐｈｉｃ Ｐｒｏｃｅｓｓｏｒ１３５によって行うものとする。
【００８０】
次に、ステップＳ１２０３において、メインコントローラ１１１がＤＲＡＭ１１６上の画像データをＧｒａｐｈｉｃ Ｐｒｏｃｅｓｓｏｒ１３５に転送する。そして、ステップＳ１２０４において、Ｇｒａｐｈｉｃ Ｐｒｏｃｅｓｓｏｒ１３５はコピー設定パラメータに基づいて画像処理を行う。例えば、拡大４００％の設定がなされていれば、Ｇｒａｐｈｉｃ Ｐｒｏｃｅｓｓｏｒ１３５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。この画像データの画像処理が完了するとステップＳ１２０５へ進む。このステップＳ１２０５では、Ｇｒａｐｈｉｃ Ｐｒｏｃｅｓｓｏｒ１３５は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。これにより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。
【００８１】
次に、ステップＳ１２０６において、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へ転送する。
【００８２】
そして、ステップＳ１２０７において、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。この画像データの転送が完了すると、即ち、このコピージョブが終了すると、プリント出力を終了する。
【００８３】
＜スキャナＩ／Ｆ１４０による原稿の特徴抽出＞
図１３は、スキャナＩ／Ｆ１４０の詳細な構成を示すブロック図である。尚、図５及び図６に示したスキャナ画像処理を担う部分は同じ符号を付している。
【００８４】
図１３に示すように、リーダー部２００で読み込まれ、ＲＧＢ信号に変換されたデジタル画像データは、リーダー部２００からの制御信号１３０１により同期を取りながら、像域分離（文字判定）部１３０２に入力される。像域分離（文字判定）部１３０２は、制御信号１３０１の同期信号を１画素分受信すると、画素カウンタ１３０３をカウントアップする。ここで、像域分離（文字判定）部１３０２は、入力された画像データが原稿の文字部分を読み込んだものか、写真又は絵の部分を読み込んだものかを判定する。判定した結果、原稿の文字部分の画像データである場合には像域分離（文字判定）部１３０２は文字カウンタ１３０４をカウントアップする。
【００８５】
上述の文字判定処理と同時に、入力された画像データはつなぎ＆ＭＴＦ補正部５０１で補正処理を施された後、入力マスキング部５０２で強調処理等を施されると同時にフィルタ６０１を介して色判定部６０３に入力され、レジスタ６０７〜６１０に設定されたＡＣＳ判定領域に従ってＡＣＳ判定領域検出回路６０２がＡＣＳ判定領域であると判断した領域の色判定を行う。また、色判定部６０３で入力された画素が有彩色であると判定した場合、色判定部６０３はＡＣＳカウンタ６０４をカウントアップする。
【００８６】
このように、図１３に示す構成により、リーダー部２００からスキャナＩ／Ｆ１４０に入力された画像データに基づいて全ての画素数が画素カウンタ１３０３でカウントされ、原稿の文字領域をスキャンしたと判断された画素数が文字カウンタ１３０４でカウントされ、有彩色（色がある）と判断された画素数がＡＣＳカウンタ６０４でカウントされ、原稿の特徴が抽出される。ここで、原稿の特徴としては、白黒多値、ハーフトーン二値、単純二値、カラー多値などで、詳細は更に後述する。
【００８７】
図１４は、本実施形態における変換処理を説明するためのブロック図である。尚、図４及び図８に示した部分と同じものには同じ符号を付している。
【００８８】
本実施形態における変換処理は、リーダー部２００で読み込まれ、ＲＧＢ信号に変換された画像データを上述のスキャナＩ／Ｆ１４０で抽出された原稿の特徴に応じて白黒多値、ハーフトーン二値、単純二値、カラー多値のフォーマットに変換し、ＨＤ１６２に格納する処理である。
【００８９】
まず、リーダー部２００から入力された画像データはスキャナＩ／Ｆ１４０で判定処理が行われた後、バスコントローラ１１３を介してＤＲＡＭ１１６に格納される。ここで格納された画像データは、ＣＰＵ１１２の指示に従ってＧｒａｐｈｉｃ Ｐｒｏｃｅｓｓｏｒ１３５の画像回転部８０１、画像変倍部８０２、色空間変換部８０３、画像二値化部８０５で、それぞれ回転処理、変倍処理、色空間変換処理、二値化処理が行われ、バスコントローラ１１３を介して再度ＤＲＡＭ１１６に保存される。そして、ＤＲＡＭ１１６上でＣＰＵ１１２によってＭＭＲ処理、ＪＰＥＧ処理などの圧縮処理が行われた後、バスコントローラ１１３を介してＩ／Ｏ制御部１２６に送られ、Ｉ／Ｏ制御部１２６にコネクタ１６１で接続されているＨＤドライブ１６０を介してＨＤ１６２に転送されて格納される。
【００９０】
図１５は、本実施形態における変換処理を示すフローチャートである。まず、プラテンガラス２１１上の原稿がＣＣＤ２１８に読み込まれ、リーダー画像処理部２２２でアナログ・デジタル変換された画像データは、スキャナＩ／Ｆ１４０で上述した原稿の特徴を抽出する処理（文字領域判定、色判定）が行われた後、バスコントローラ１１３を介してＤＲＡＭ１１６に格納される（ステップＳ１５０１）。次に、ＣＰＵ１１２は読み込んだ画像データの領域の情報を判断するために、画素カウンタ１３０３、文字カウンタ１３０４からそれぞれのカウンタ値を取得する。そして、画素カウンタ１３０３のカウンタ値をＣｔ、文字カウンタ１３０４のカウンタ値をＣｍとしてＤＲＡＭ１１６に保存する（ステップＳ１５０２）。
【００９１】
次に、ＣＰＵ１１２は読み込まれた画像データの色判定の結果を判断するために、ＡＣＳカウンタ６０４のカウンタ値を取得し、ＣｃとしてＤＲＡＭ１１６に保存する（ステップＳ１５０３）。そして、ＣＰＵ１１２は、ＤＲＡＭ１１６に保存されている画像データが白黒原稿を読み込んだものと判定したときに変換するファイルの種別を決定するための係数をＲＯＭ１１４から取得する（ステップＳ１５０４）。このファイル種別を決定するための係数は、単純二値ファイルに変換するための係数Ｔｂとハーフトーン二値ファイルに変換するための係数Ｔｈがある。
【００９２】
ここで、ＣＰＵ１１２は、取得したＡＣＳカウンタ６０４のカウンタ値Ｃｃを判断し、Ｃｃ≠０の場合には、読み込んだ画像データに有彩色部分がある、即ち色が付いたカラー原稿を読み込んだと判断し（ステップＳ１５０５のＹＥＳ）、色空間変換部８０３にカラー画像生成用のパラメータを設定し、ＬＵＴ８０４にカラー画像生成用のテーブルを設定した後、ＤＲＡＭ１１６からバスコントローラ１１３を介して色空間変換部８０３に画像データを転送してカラー用の色空間変換を行い、再度ＤＲＡＭ１１６に格納する。その後、カラー用の画像処理が施されたＤＲＡＭ１１６上の画像データをＤＲＡＭ１１６上でＪＰＥＧ圧縮する（ステップＳ１５１１）。
【００９３】
また、ステップＳ１５０５で、ＣＰＵ１１２は取得したＡＣＳカウンタ６０４のカウンタ値Ｃｃを判断し、Ｃｃ＝０の場合には、読み込んだ画像データに有彩色部分がない、即ち色の付いていない白黒原稿を読み込んだと判断し、白黒画像のファイル判定を行う処理（ステップＳ１５０６）へ進む。
【００９４】
ここで、ＣＰＵ１１２は、取得した画素カウンタ１３０３のカウンタ値Ｃｔ、文字カウンタ１３０４のカウンタ値Ｃｍ、単純二値ファイルに変換するための係数Ｔｂとハーフトーン二値ファイルに変換するための係数Ｔｈに基づき、次式が満たされるか否かを判断する。
【００９５】
Ｃｍ／Ｃｔ＞Ｔｂ （式１）
上記の式１が満たされた場合、即ち総画素数に対して文字と判断された画素数が予め定められている単純二値ファイルにするための係数値より大きいと判断し（ステップＳ１５０６のＹＥＳ）、ＤＲＡＭ１１６に保存されている画像データから単純二値のファイルを作成するために、色空間変換部８０３に白黒単純二値用のパラメータを設定し、ＬＵＴ８０４に白黒単純二値画像生成用のテーブルを設定した後、ＤＲＡＭ１１６からバスコントローラ１１３を介して色空間変換部８０３に画像データを転送して白黒単純二値用の色空間変換を行い、画像二値化部８０５で多値→二値変換を行った後、再度ＤＲＡＭ１１６に格納する。その後、白黒単純二値用の画像処理が施されたＤＲＡＭ１１６上の画像データをＤＲＡＭ１１６上でＭＭＲ圧縮する（ステップＳ１５１０）。
【００９６】
また、ＣＰＵ１１２は上記の式１が満たされないと判断した場合（ステップＳ１５０６のＮＯ）、次の式２が満たされるか否かを判断する。
【００９７】
Ｔｂ≧Ｃｍ／Ｃｔ＞Ｔｈ （式２）
上記の式２が満たされた場合、即ち総画素数に対して文字と判断された画素数が予め定められている単純二値ファイルにするための係数値より小さく、ハーフトーン二値ファイルにするための係数より大きいと判断し（ステップＳ１５０７のＹＥＳ）、ＤＲＡＭ１１６に保存されている画像データからハーフトーン二値のファイルを作成するために、色空間変換部８０３にハーフトーン二値用のパラメータを設定し、ＬＵＴ８０４に白黒ハーフトーン二値画像生成用のテーブルを設定した後、ＤＲＡＭ１１６からバスコントローラ１１３を介して色空間変換部８０３に画像データを転送して白黒ハーフトーン二値の色空間変換を行い、画像二値化部８０５で多値→二値変換を行った後、再度ＤＲＡＭ１１６に格納する。その後、白黒ハーフトーン二値用の画像処理が施されたＤＲＡＭ１１６上の画像データをＤＲＡＭ１１６３上でＭＭＲ圧縮する（ステップＳ１５０９）。
【００９８】
一方、ＣＰＵ１１２は上記の式１、式２のどちらも満たさないと判断した場合（ステップＳ１５０７のＮＯ）、ＤＲＡＭ１１６に保存されている画像データから白黒多値の画像ファイルを作成するために、色空間変換部８０３に白黒多値用のパラメータを設定し、ＬＵＴ８０４に白黒多値画像生成用のテーブルを設定した後、ＤＲＡＭ１１６からバスコントローラ１１３を介して色空間変換部８０３に画像データを転送して白黒多値用の色空間変換を行い、再度ＤＲＡＭ１１６に格納する。その後、白黒多値用の画像処理が施されたＤＲＡＭ１１６上の画像データをＤＲＡＭ１１６上でＪＰＥＧ圧縮する（ステップＳ１５０８）。
【００９９】
そして、ＣＰＵ１１２は、上述したステップＳ１５０８〜Ｓ１５１１において所定の変換が行われた画像データをＤＲＡＭ１１６からバスコントローラ１１３を介してＩ／Ｏ制御部１２６に送出し、Ｉ／Ｏ制御部１２６にコネクタ１６１により接続されているＨＤドライブ１６０を介してＨＤ１６２に転送して格納する（ステップＳ１５１２）。
【０１００】
以上説明したように、本実施形態によれば、画像入出力装置の原稿読取手段で原稿を読み取り、読み取った原稿の画像データに基づいて原稿の特徴を抽出し、その原稿の特徴に応じて画像データの色空間変換、多値二値変換、圧縮形式などの切り替えを行い、読み取った原稿に最適な画像フォーマットに変換することができる。
【０１０１】
尚、本発明は複数の機器（例えば、ホストコンピュータ，インターフェース機器，リーダ，プリンタなど）から構成されるシステムに適用しても、１つの機器からなる装置（例えば、複写機，ファクシミリ装置など）に適用しても良い。
【０１０２】
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を、システム或いは装置に供給し、そのシステム或いは装置のコンピュータ（ＣＰＵ若しくはＭＰＵ）が記録媒体に格納されたプログラムコードを読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。
【０１０３】
この場合、記録媒体から読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憶した記録媒体は本発明を構成することになる。
【０１０４】
このプログラムコードを供給するための記録媒体としては、例えばフロッピー（登録商標）ディスク，ハードディスク，光ディスク，光磁気ディスク，ＣＤ−ＲＯＭ，ＣＤ−Ｒ，磁気テープ，不揮発性のメモリカード，ＲＯＭなどを用いることができる。
【０１０５】
また、コンピュータが読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ＯＳ（オペレーティングシステム）などが実際の処理の一部又は全部を行い、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。
【０１０６】
更に、記録媒体から読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ボ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、その機能拡張ボ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又は全部を行い、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。
【０１０７】
【発明の効果】
以上説明したように、本発明によれば、ユーザーが煩雑な作業を行うことなく、最適な階調性と圧縮形式の画像データに変換することができる。
【図面の簡単な説明】
【図１】本実施形態における画像入出力システムの全体構成を示す図である。
【図２】リーダー部２００及びプリンタ部３００の側断面図である。
【図３】リーダー画像処理部２２２の詳細な構成を示すブロック図である。
【図４】制御装置１１０の構成を示すブロック図である。
【図５】スキャナ画像処理を担う部分の詳細な構成を示すブロック図である。
【図６】ＡＣＳ（オートカラーセレクト）カウント部５０３の構成を示す図である。
【図７】プリンタＩ／Ｆの画像処理の詳細な構成を示すブロック図である。
【図８】Ｇｒａｐｈｉｃ Ｐｒｏｃｅｓｓｏｒ１３５の詳細な構成を示すブロック図である。
【図９】画像回転部８０１での画像転送を説明するための図である。
【図１０】画像回転部８０１での画像回転を説明するための図である。
【図１１】本実施形態におけるＰＤＬ画像出力の手順を示すフローチャートである。
【図１２】本実施形態におけるコピー画像出力の手順を示すフローチャートである。
【図１３】スキャナＩ／Ｆ１４０の詳細な構成を示すブロック図である。
【図１４】本実施形態における変換処理を説明するためのブロック図である。
【図１５】本実施形態における変換処理を示すフローチャートである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for converting the image format of an original according to the characteristics of the original read by the original reading means.
[0002]
[Prior art]
Conventionally, in an image input / output device, a document is read by an optical reader of the image input / output device, stored as a digital image, and the stored digital image is transferred to a host computer connected to the image input / output device through a network interface or the like. To be done.
[0003]
In general, a digital image created by reading a document image and transferred from an image input / output device to a computer connected via a network interface or the like is a JPEG compression format that is an image format that can be handled by an application of a transfer destination computer. , Converted into a TIFF-MMR compression format and the like.
[0004]
Also, in an image input / output device that can handle color originals, the transfer destination computer considers the color reproducibility of the originals, etc., and determines whether the color originals or black and white originals are determined by the original reading means of the image input / output device. In this case, the image format is converted to a JPEG compression format, and in the case of a monochrome document, the image format is converted to a TIFF-MMR compression format (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
JP 2001-309189 A
[Problems to be solved by the invention]
However, in the above-described conventional example, in the case of a newspaper or magazine that is a black and white manuscript with many picture or photo parts, if it is simply converted into a black and white binary TIFF-MMR compressed image format, the floor of the picture or picture part will be displayed. There is a problem that the tonality is lost.
[0006]
In order to solve this problem, even a black-and-white document may be converted into an image format that is compressed with multiple values such as a JPEG compression format. In this case, the image data is compared with the image format of the TIFF-MMR compression format. This causes a problem that the amount of data increases.
[0007]
In order to solve such a problem, there is a means for the user to select an image format. In this case, when transferring a plurality of documents to a computer, the image file format of the documents is specified one by one. Thus, the user must repeat the operation of reading the document, which places a heavy load on the user.
[0008]
The present invention has been made to solve the above-described problems, and an object of the present invention is to convert the image data into optimal gradation and compression format image data without a complicated operation by the user.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a format conversion method for converting the image format of an original according to the characteristics of the original read by the original reading means, and converts the image data of the original read by the original reading means into image data of the original. And extracting a feature of the document based on the document, and converting an image format of the image data in accordance with the extracted feature of the document.
[0010]
In order to achieve the above object, the present invention provides an image processing apparatus for converting the image format of an original according to the characteristics of the original read by the original reading means, the image data of the original read by the original reading means. Extracting means for extracting the features of the original document based on the above, converting means for converting the image format of the image data in accordance with the extracted feature of the original document, and storing means for storing the image data converted from the image format It is characterized by having.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 is a diagram illustrating an overall configuration of an image input / output system according to the present embodiment. As shown in FIG. 1, a reader unit (image input device) 200 optically reads a document image, converts it into image data, and outputs it. The reader unit 200 includes a scanner unit 210 having a function for reading a document and a document feeding unit (DF unit) 250 having a function for transporting document sheets.
[0013]
On the other hand, the printer unit (image output apparatus) 300 conveys the recording paper, prints the image data as a visible image on the recording paper, and discharges the recording paper outside the apparatus. The printer unit 300 includes a paper feed unit 360 having a plurality of types of recording paper cassettes, a marking unit 310 having a function of transferring and fixing image data onto the recording paper, and a machine that sorts and staples the printed recording paper. And a paper discharge unit 370 having a function of outputting to the outside.
[0014]
In addition, the control unit (the controller unit 110 is electrically connected to the reader unit 200 and the printer unit 300, and is further connected to host computers (PCs) 401 and 402 via the network 400. A copy function is provided for controlling the reader unit 200 to read image data of an original and for controlling the printer unit 300 to output the image data to a recording sheet.The image data read from the reader unit 200 is converted into code data. A scanner function for converting and transmitting to the host computer via the network 400 and a printer function for converting code data received from the host computer via the network 400 to image data and outputting the image data to the printer unit 300 are provided.
[0015]
The operation unit 150 is connected to the control device 110 and is configured by a liquid crystal touch panel, and provides a user I / F for operating the image input / output system 100.
[0016]
FIG. 2 is a side sectional view of the reader unit 200 and the printer unit 300. The document feeding unit 250 of the reader unit 200 feeds documents one by one on the platen glass 211 in order from the top, and discharges the documents on the platen glass 211 after the document reading operation is completed. When the document is conveyed onto the platen glass 211, the lamp 212 is turned on, and the movement of the optical unit 213 is started to expose and scan the document. The reflected light from the original at this time is guided to a CCD image sensor (hereinafter referred to as CCD) 218 by mirrors 214, 215 and 216 and a lens 217. Thus, the scanned image of the original is read by the CCD 218.
[0017]
In the reader unit 200, 222 is a reader image processing unit, which performs predetermined processing on the image data output from the CCD 218 and outputs it to the control device 110 via the scanner I / F.
[0018]
In the printer unit 300, a printer image processing unit 352 outputs an image signal sent from the control device 110 to the laser driver 317 via the printer I / F. The laser driver 317 drives the laser light emitting units 313, 314, 315, and 316, and laser light corresponding to the image data output from the printer image processing unit 352 is emitted from the laser light emitting units 313, 314, 315, and 316. Make it emit light. This laser beam is applied to the photosensitive drums 325, 326, 327, 328 by mirrors 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, and the photosensitive drums 325, 326, 327, 328, A latent image corresponding to the laser beam is formed at 328. Reference numerals 321, 322, 323, and 324 are developing units for developing a latent image with black (Bk), yellow (Y), cyan (C), and magenta (M) toners, respectively. Is transferred to paper and printed out in full color.
[0019]
A sheet fed from one of the sheet cassettes 360 and 361 and the manual feed tray 362 at a timing synchronized with the start of laser beam irradiation is attracted onto the transfer belt 334 via a registration roller 333 and conveyed. Then, the developer attached to the photosensitive drums 325, 326, 327, and 328 is transferred to a recording sheet. The recording paper on which the developer is placed is conveyed to the fixing unit 335, and the developer is fixed on the image 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 the paper discharge unit 370 bundles the discharged recording paper and sorts the recording paper, or after stapling the sorted recording paper, Place on 371.
[0020]
If double-sided recording is set, the recording paper is conveyed to the discharge roller 336 and then the rotation direction of the discharge roller 336 is reversed and guided to the refeed conveyance path 338 by the flapper 337. The recording sheet guided to the refeed conveyance path 338 is fed to the transfer belt 334 at the timing described above.
[0021]
<Description of Reader Image Processing Unit>
FIG. 3 is a block diagram illustrating a detailed configuration of the reader image processing unit 222. In the reader image processing unit 222, the original on the platen glass 211 is read by the CCD 218 and converted into an electrical signal (in the case of a color sensor, the RGB color filter is mounted inline in RGB order on the one-line CCD. Or a three-line CCD in which an R filter, a G filter, and a B filter are arranged for each CCD, or the filter may be on-chip or the filter may be configured separately from the CCD). Then, the electrical signal (analog image signal) is input to the reader image processing unit 222, and clamp & Amp. & S / H & A / D unit 301 performs sample hold (S / H), clamps the dark level of the analog image signal to the reference potential, and amplifies the analog image signal to a predetermined amount (the above processing order is not limited to the notation order). D-converted and converted into, for example, an 8-bit RGB digital signal. The RGB signals are subjected to shading correction and black correction by the shading unit 302 and then output to the control device 110.
[0022]
<Description of control device>
Next, functions of the control device 110 will be described with reference to a block diagram shown in FIG. As shown in FIG. 4, the main controller 111 mainly includes a CPU 112, a bus controller 113, and various I / F controller circuits.
[0023]
The CPU 112 and the bus controller 113 control the overall operation of the control device 110, and the CPU 112 operates based on a program read from the ROM 114 via the ROM I / F 115. The operation of interpreting PDL (page description language) code data received from the host computer 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 control of DMA data transfer.
[0024]
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 CPU 112 to operate and an area for storing image data.
[0025]
The Codec 118 compresses the raster image data stored in the DRAM 116 by a method such as MH / MR / MMR / JBIG / JPEG, and conversely expands the compressed and stored code data to 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.
[0026]
The graphic processor 135 performs image rotation, image scaling, color space conversion, binarization, scanner image input, and printer image output processing on the 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 transfer.
[0027]
The network controller 121 is connected to the main controller 111 via the I / F 123 and is connected to an external network via the connector 122. As a network, Ethernet (registered trademark) is generally used.
[0028]
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. A general-purpose high-speed bus is generally a PCI bus.
[0029]
The I / O control unit 126 is equipped with two channels of an asynchronous serial communication controller 127 for transmitting and receiving control commands to and from the CPUs of the reader unit 200 and the printer unit 300. F circuits 140 and 145 are connected.
[0030]
The panel I / F 132 is connected to the LCD controller 131 and includes an I / F for displaying on a liquid crystal screen on the operation unit 150 and a key input I / F 130 for inputting hardware keys, touch panel keys, and the like. Composed.
[0031]
The operation unit 150 includes a liquid crystal display unit, a touch panel input device attached to the liquid crystal display unit, and a plurality of hard keys. A signal input by the touch panel or the hard key is transmitted to the CPU 112 via the panel I / F 132 described above, and the liquid crystal display unit displays the image data sent from the panel I / F 132. On the liquid crystal display unit, function display, image data, and the like in the operation of the image forming apparatus are displayed.
[0032]
The real time clock module 133 is for updating / saving the date and time managed in the apparatus, and is backed up by a backup battery 134.
[0033]
The E-IDE interface 161 is for connecting an external storage device. In this embodiment, an HD (hard disk) drive 160 is connected via the I / F 161. The hard disk 162 stores programs and image data.
[0034]
The connectors 142 and 147 are connected to the reader unit 200 and the printer unit 300, respectively, and are composed of synchronized step-synchronized serial I / Fs 143 and 148 and video I / Fs 144 and 149.
[0035]
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 the image received from the reader unit 200. Further, it 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.
[0036]
Data transfer from the scanner bus 141 to the DRAM 116 is controlled by the bus controller 113.
[0037]
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 performs predetermined processing on the image data output from the main controller 111, and the printer unit And a function of outputting a control signal generated based on the video control signal sent from the printer unit 300 to the printer bus 146.
[0038]
Transfer of raster image data developed on the DRAM 116 to the printer unit 300 is controlled by the bus controller 113 and DMA-transferred to the printer unit 300 via the printer bus 146 and the video I / F 149.
[0039]
<Description of scanner image processing>
Next, the scanner image processing in the scanner I / F 140 will be described in detail. FIG. 5 is a block diagram showing a detailed configuration of a portion responsible for scanner image processing.
[0040]
With respect to the image signal sent from the reader unit 200 shown in FIG. 5 via the connector 142, the connection & MTF correction unit 501 adjusts the delay amount for each line according to the reading speed, and corrects the MTF that has changed according to the reading speed. When the CCD 218 is a 3-line CCD, the connecting process corrects the signal timing so that the reading positions of the 3 lines are the same. The digital signal whose reading position timing is corrected corrects the spectral characteristics of the CCD 218 and the spectral characteristics of the lamp 212 and the mirrors 214, 215 and 216 by the input masking unit 502. The output of the input masking unit 502 is sent to the ACS count unit 503 and the main controller 111.
[0041]
<Description of ACS Count Unit>
Here, the ACS (auto color select) counting unit 503 will be described with reference to FIG.
[0042]
Auto color selection (hereinafter referred to as ACS) determines whether a document is color or monochrome. That is, color determination is performed based on how many pixels are equal to or greater than a threshold value for which the saturation for each pixel is obtained. However, even for a black and white document, due to the influence of MTF and the like, when viewed microscopically, there are many color pixels around the edge, and it is difficult to simply perform ACS determination on a pixel basis. Although various methods are provided for this ACS method, in this embodiment, since it is not particular to the ACS method, a description will be given by a very general method.
[0043]
As described above, even in a black and white image, there are many color pixels when viewed microscopically. Therefore, whether or not the pixel is really a color pixel is determined based on information on surrounding color pixels with respect to the target pixel. There is a need. In FIG. 6, reference numeral 601 denotes a determination filter, which has a FIFO structure in order to refer to surrounding pixels with respect to the target pixel. Reference numeral 602 denotes a circuit that creates an area signal 605 to be subjected to ACS based on the values set in the registers 607 to 610 set by the main controller 111 and the video control signal 612 sent from the reader unit 200. A color determination unit 603 refers to a peripheral pixel in the memory of the filter 601 with respect to the pixel of interest based on the area signal 605 to which ACS is applied, and determines whether the pixel of interest is a color pixel or a monochrome pixel. It is. Reference numeral 604 denotes a counter that counts the number of color determination signals output from the color determination unit 603.
[0044]
The main controller 111 determines an area to be subjected to ACS with respect to the reading range, and sets it in the registers 607 to 610 (in this embodiment, the range is determined independently for the original). Further, the main controller 111 compares the value of a counter that counts the number of color determination signals in the area to which ACS is applied with a predetermined threshold value, and determines whether the document is color or monochrome.
[0045]
In the registers 607 to 610, the position where the color determination unit 603 starts the determination and the position where the determination ends are set in the main scanning direction and the sub-scanning direction based on the video control signal 612 sent from the reader unit 200. Shall be kept. In this embodiment, each size is set to be about 10 mm smaller than the actual document size.
[0046]
Note that the ACS mode is used to determine whether the image signal is color or black and white, and the output mode is the ACS mode. The mode that always outputs the full color image signal is the color mode. The mode that always outputs the black and white image signal is the black and white mode. To do.
[0047]
<Description of Image Processing of Printer I / F>
A detailed description will be given of a portion of the printer I / F 145 responsible for image processing. FIG. 7 is a block diagram showing a detailed configuration of image processing of the printer I / F.
[0048]
An image signal sent from the main controller 111 via the printer bus 146 is first input to the LOG conversion unit 701. The LOG conversion unit 701 converts RGB signals into CMY signals by LOG conversion. Next, moire is removed by the moire removing unit 702. The CMY signal that has undergone moire removal processing by the UCR & masking unit 703 generates a CMYK signal by UCR processing, and the masking processing unit corrects the CMY signal to a signal that matches the output of the printer. The signal processed by the UCR & masking unit 703 is subjected to density adjustment by the γ correction unit 704 and then smoothed or edge processed by the filter unit 705. Through these processes, an image is sent to the printer unit 300 via the connector 147.
[0049]
<Description of Graphic Processor>
Next, the graphic processor 135 will be described in detail. FIG. 8 is a block diagram showing a detailed configuration of the graphic processor 135.
[0050]
The graphic processor 135 has modules that respectively perform image rotation, image scaling, color space conversion, and binarization. The SRAM 136 is used as a temporary work area for each module of the graphic processor 135. The work area is statically assigned to each module in advance so that the work area of the SRAM 136 used by each module does not compete. 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 transfer.
[0051]
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.
[0052]
Hereinafter, each processing procedure of the image rotation unit 801, the image scaling unit 802, the color space conversion unit 803, and the image binarization unit 805 in the graphics processor 135 will be described in detail.
[0053]
<Description of image rotation unit>
First, a processing procedure in the image rotation unit 801 is shown. The CPU 112 sets the bus controller 113 for image rotation control. With this setting, the bus controller 113 performs settings necessary for image rotation (for example, image size, rotation direction and angle, etc.) to the image rotation unit 801 via the I / F 137. After performing the necessary settings, the CPU 112 again permits image data transfer to the bus controller 113. In accordance with this permission, the bus controller 113 starts transferring image data from the DRAM 116 or a device connected via each I / F. Here, the image size to be rotated is 32 pixels × 32 lines, and when transferring the image data on the image bus, the image transfer is performed in units of 24 bytes (each pixel is 8 bits for RGB). To do.
[0054]
As described above, in order to obtain an image of 32 pixels × 32 lines, it is necessary to transfer the above unit data 32 × 32 times, and it is necessary to transfer image data from discontinuous addresses (FIG. 9). reference).
[0055]
The image data transferred by the discontinuous addressing is written in the SRAM 136 so as to be rotated at a desired angle at the time of reading. For example, if the rotation is 90 degrees counterclockwise, the transferred image data is written in the Y direction as shown in FIG. 10, and the image is rotated by reading it in the X direction at the time of reading.
[0056]
After the image rotation of 32 pixels × 32 lines (writing to the SRAM 136) is completed, the image rotation unit 801 reads the image data from the SRAM 136 by the reading method described above, and transfers the image to the bus controller 113. 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 by continuous addressing.
[0057]
Such a series of processes is repeated until there is no processing request from the CPU 112 (when the necessary number of pages have been processed).
[0058]
<Description of image scaling unit>
Next, a processing procedure in the image scaling unit 802 will be shown. The CPU 112 performs settings for image scaling control in the bus controller 113. With this setting, the bus controller 113 makes settings necessary for image scaling to the image scaling unit 802 via the I / F 137 (magnification in the main scanning direction, scaling in the sub-scanning direction, and image size after scaling. Etc.). After performing the necessary settings, the CPU 112 again permits image data transfer to the bus controller 113. In accordance with this permission, the bus controller 113 starts transferring image data from the DRAM 116 or a device connected via each I / F.
[0059]
The image scaling unit 802 stores the received image data in the temporary SRAM 136, uses this as an input buffer, and uses the stored data for the number of pixels and lines necessary for the main scanning and sub-scanning scaling ratios. The scaling process is performed by enlarging or reducing the image by performing only the interpolation process. The scaled data is written back to the SRAM 136 again, and this is used as an output buffer. The image scaling unit 802 reads the image data from the SRAM 136 and transfers it to the bus controller 113.
[0060]
The bus controller 113 that has received the image data subjected to the scaling process as described above transfers the data to the DRAM 116 or each device on the I / F.
[0061]
<Description of Color Space Conversion Unit>
Next, a processing procedure in the color space conversion unit 803 will be shown. The CPU 112 performs settings for color space conversion control in the bus controller 113. With this setting, the bus controller 113 makes settings necessary for the color space conversion processing for the color space conversion unit 803 and the LUT (lookup table) 804 via the I / F 137 (coefficients for matrix operation described later, table values of the LUT 804). Etc.). After making the necessary settings, the CPU 112 again permits image data transfer to the bus controller 113. In accordance with this permission, the bus controller 113 starts transferring image data from the DRAM 116 or a device connected via each I / F.
[0062]
The color space conversion unit 803 first performs a 3 × 3 matrix operation represented by the following equation for each pixel of the received image data.
[0063]
[Expression 1]

[0064]
In the above formula, R, G, B are input, X, Y, Z are output, a ₁₁ , A ₁₂ , A ₁₃ , A ₂₁ , A ₂₂ , A ₂₃ , A ₃₁ , A ₃₂ , A ₃₃ , B ₁ , B ₂ , B ₃ , C ₁ , C ₂ , C ₃ Are the coefficients.
[0065]
Various color space conversions such as conversion from the RGB color space to the Yuv color space can be performed by the calculation of the above formula.
[0066]
Next, conversion by the LUT 804 is performed on the data after matrix calculation. Thereby, nonlinear conversion can also be performed. Of course, the LUT conversion may not be performed substantially by setting a through table. Thereafter, the color space conversion unit 803 transfers the image data subjected to the color space conversion processing to the bus controller 113.
[0067]
The bus controller 113 that has received the image data subjected to the color space conversion processing as described above transfers the data to the DRAM 116 or each device on the I / F.
[0068]
<Description of Image Binarization Unit>
Next, a processing procedure in the image binarization unit 805 is shown. The CPU 112 performs settings for binarization control in the bus controller 113. With this setting, the bus controller 113 performs settings necessary for binarization processing (various parameters and the like according to the conversion method) to the image binarization unit 805 via the I / F 137. After performing the necessary settings, the CPU 112 again permits image data transfer to the bus controller 113. In accordance with this permission, the bus controller 113 starts transferring image data from the DRAM 116 or a device connected via each I / F.
[0069]
The image binarization unit 805 performs binarization processing on the received image data. In the present embodiment, as a binarization method, image data is compared with a predetermined threshold value and is simply binarized. Of course, any method such as a dither method, an error diffusion method, an error diffusion method, or an improved method may be used.
[0070]
Thereafter, the image binarization unit 805 transfers the binarized image data to the bus controller 113. The bus controller 113 that has received the binarized image data transfers the data to the DRAM 116 or each device on the I / F.
[0071]
<Sequence when outputting PDL image>
FIG. 11 is a flowchart showing a procedure for outputting a PDL image in the present embodiment. When outputting a PDL image, first, in step S1101, the user performs print settings for the PDL image output job on the PC 401. The contents of the print settings include the number of copies, paper size, single side / double side, page output order, sort output, presence or absence of stapling.
[0072]
In step S1102, when a print instruction is given on the PC 401, the driver software installed on the PC 401 converts the code data on the PC 401 to be printed into so-called PDL data. Then, the PDL data is transferred via the network 400 to the control device 110 of the image input / output system 100 together with the print setting parameters set in step S1101.
[0073]
In step S1103, the CPU 112 of the main controller 111 in the control device 110 expands (rasterizes) the PDL data transferred through the connector 122 and the network controller 121 into image data based on the print setting parameters. Note that the image data is developed on the DRAM 116. When the development of the image data is completed, the process proceeds to step S1104, and the main controller 111 transfers the image data developed on the DRAM 116 to the graphic processor 135.
[0074]
Next, in step S1105, the graphic processor 135 performs image processing independently of the print setting parameters. For example, when the paper size specified by the print setting parameter is A4 but the paper feed 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 that matches the output paper. When the image processing of the image data is completed, the process proceeds to step S1106, and 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.
[0075]
In step S <b> 1107, 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.
[0076]
In step S1108, the control device 110 controls the printer unit 300 to print out the image data. When the transfer of the image data is completed, that is, when the PDL job is finished, the print output is finished.
[0077]
<Sequence when outputting copy image>
FIG. 12 is a flowchart showing a copy image output procedure in the present embodiment. When outputting a copy image, first, in step S1201, the user performs copy settings for the copy image output job on the operation unit 150. The contents of the copy settings include the number of copies, paper size, single / double-sided, enlargement / reduction ratio, sort output, presence or absence of stapling.
[0078]
In step S1202, when a copy start instruction is given from 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. Perform the action. Here, the documents on which the document feeding unit 250 is placed are fed one by one onto the platen glass 211, and the size of the document is detected at the same time. 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. A conventional copier realizes a scaling process in the sub-scanning direction by changing the moving speed of the optical unit 213 according to the setting of the enlargement / reduction ratio of the copy setting, that is, according to the scaling ratio in the sub-scanning direction. Was.
[0079]
However, in the present embodiment, the image data is always read at the same magnification (100%) regardless of the enlargement / reduction ratio setting of the copy setting, and the scaling process is performed by the graphic processor 135 in both the main scanning direction and the sub-scanning direction. Assumed to be performed.
[0080]
In step S <b> 1203, the main controller 111 transfers image data on the DRAM 116 to the graphic processor 135. In step S1204, the graphic processor 135 performs image processing based on the copy setting parameters. For example, if an enlargement of 400% is set, a scaling process in both the main scanning direction and the sub-scanning direction is performed using the image scaling unit 802 which is a module in the graphic processor 135. When the image processing of this image data is completed, the process proceeds to step S1205. In step S <b> 1205, the graphic processor 135 transfers the image data after image processing to the main controller 111. As a result, the main controller 111 stores the transferred image data on the DRAM 116.
[0081]
In step S <b> 1206, 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.
[0082]
In step S1207, the control device 110 controls the printer unit 300 to print out the image data. When the transfer of the image data is completed, that is, when the copy job is finished, the print output is finished.
[0083]
<Original Document Feature Extraction by Scanner I / F 140>
FIG. 13 is a block diagram illustrating a detailed configuration of the scanner I / F 140. The parts responsible for scanner image processing shown in FIGS. 5 and 6 are given the same reference numerals.
[0084]
As shown in FIG. 13, digital image data read by the reader unit 200 and converted into RGB signals is input to an image area separation (character determination) unit 1302 while being synchronized by a control signal 1301 from the reader unit 200. Is done. When the image area separation (character determination) unit 1302 receives the synchronization signal of the control signal 1301 for one pixel, the image area separation (character determination) unit 1302 counts up the pixel counter 1303. Here, the image area separation (character determination) unit 1302 determines whether the input image data is read from a character portion of a document or a photo or picture portion. As a result of the determination, when the image data is the character portion of the document, the image area separation (character determination) unit 1302 counts up the character counter 1304.
[0085]
Simultaneously with the character determination processing described above, the input image data is subjected to correction processing by the stitching & MTF correction unit 501 and then subjected to emphasis processing or the like by the input masking unit 502 and at the same time via the filter 601 In accordance with the ACS determination region set in the registers 607 to 610, the ACS determination region detection circuit 602 determines the color of the region determined to be the ACS determination region. When the color determination unit 603 determines that the input pixel is a chromatic color, the color determination unit 603 increments the ACS counter 604.
[0086]
In this way, with the configuration shown in FIG. 13, the number of all pixels is counted by the pixel counter 1303 based on the image data input from the reader unit 200 to the scanner I / F 140, and it is determined that the character area of the document has been scanned. The number of pixels counted is counted by the character counter 1304, and the number of pixels determined to be a chromatic color (there is a color) is counted by the ACS counter 604, and the document features are extracted. Here, the characteristics of the document include black and white multi-value, half-tone binary, simple binary, and color multi-value, and the details will be described later.
[0087]
FIG. 14 is a block diagram for explaining the conversion processing in the present embodiment. In addition, the same code | symbol is attached | subjected to the same part as the part shown in FIG.4 and FIG.8.
[0088]
In the conversion process according to the present embodiment, the image data read by the reader unit 200 and converted into RGB signals is converted into monochrome multi-value, half-tone binary, or simple according to the characteristics of the document extracted by the scanner I / F 140 described above. This is a process of converting to a binary / color multi-value format and storing it in the HD 162.
[0089]
First, image data input from the reader unit 200 is subjected to determination processing by the scanner I / F 140 and then stored in the DRAM 116 via the bus controller 113. The image data stored here is subjected to rotation processing, scaling processing, and color by an image rotation unit 801, an image scaling unit 802, a color space conversion unit 803, and an image binarization unit 805 of the Graphic Processor 135 in accordance with instructions from the CPU 112, respectively. Spatial conversion processing and binarization processing are performed and stored again in the DRAM 116 via the bus controller 113. Then, after the CPU 112 performs compression processing such as MMR processing and JPEG processing on the DRAM 116, it is sent to the I / O control unit 126 via the bus controller 113, and is connected to the I / O control unit 126 through the connector 161. The HD drive 160 is transferred to the HD 162 for storage.
[0090]
FIG. 15 is a flowchart showing the conversion processing in this embodiment. First, the original on the platen glass 211 is read into the CCD 218, and the image data analog-digital converted by the reader image processor 222 is used to extract the above-mentioned original features by the scanner I / F 140 (character area determination, color After determination, the data is stored in the DRAM 116 via the bus controller 113 (step S1501). Next, the CPU 112 acquires respective counter values from the pixel counter 1303 and the character counter 1304 in order to determine the information of the read image data area. Then, the counter value of the pixel counter 1303 is stored as Ct and the counter value of the character counter 1304 is stored as Cm in the DRAM 116 (step S1502).
[0091]
Next, the CPU 112 acquires the counter value of the ACS counter 604 and stores it as Cc in the DRAM 116 in order to determine the color determination result of the read image data (step S1503). Then, the CPU 112 acquires, from the ROM 114, a coefficient for determining the type of file to be converted when it is determined that the image data stored in the DRAM 116 has read a black and white document (step S1504). The coefficient for determining the file type includes a coefficient Tb for converting to a simple binary file and a coefficient Th for converting to a halftone binary file.
[0092]
Here, the CPU 112 determines the obtained counter value Cc of the ACS counter 604. If Cc ≠ 0, the CPU 112 determines that the read image data has a chromatic color portion, that is, that a color document with color is read. In step S1505 (YES in step S1505), a color image generation parameter is set in the color space conversion unit 803, a color image generation table is set in the LUT 804, and the color space conversion unit 803 is connected from the DRAM 116 via the bus controller 113. The image data is transferred to the color space for color space conversion and stored in the DRAM 116 again. Thereafter, the image data on the DRAM 116 subjected to the color image processing is JPEG-compressed on the DRAM 116 (step S1511).
[0093]
In step S1505, the CPU 112 determines the acquired counter value Cc of the ACS counter 604. If Cc = 0, the read image data has no chromatic color portion, that is, a monochrome document without color is read. If not, the process proceeds to a process for determining a monochrome image file (step S1506).
[0094]
Here, the CPU 112 is based on the acquired counter value Ct of the pixel counter 1303, the counter value Cm of the character counter 1304, the coefficient Tb for conversion to a simple binary file, and the coefficient Th for conversion to a halftone binary file. Then, it is determined whether or not the following equation is satisfied.
[0095]
Cm / Ct> Tb (Formula 1)
When Equation 1 is satisfied, that is, it is determined that the number of pixels determined to be a character with respect to the total number of pixels is larger than a coefficient value for making a simple binary file set in advance (YES in step S1506). ) In order to create a simple binary file from the image data stored in the DRAM 116, a monochrome simple binary parameter is set in the color space conversion unit 803, and a monochrome simple binary image generation table is set in the LUT 804. Then, the image data is transferred from the DRAM 116 to the color space conversion unit 803 via the bus controller 113 to perform color space conversion for monochrome simple binary, and the image binarization unit 805 performs multi-value → binary conversion. Is stored in the DRAM 116 again. Thereafter, the image data on the DRAM 116 that has been subjected to the monochrome simple binary image processing is MMR-compressed on the DRAM 116 (step S1510).
[0096]
If the CPU 112 determines that the above expression 1 is not satisfied (NO in step S1506), the CPU 112 determines whether the following expression 2 is satisfied.
[0097]
Tb ≧ Cm / Ct> Th (Formula 2)
When the above equation 2 is satisfied, that is, the number of pixels determined to be a character with respect to the total number of pixels is smaller than a predetermined coefficient value for making a simple binary file, and a halftone binary file is created. Therefore, in order to create a halftone binary file from the image data stored in the DRAM 116, the color space conversion unit 803 is provided with a halftone binary parameter. After setting the black and white halftone binary image generation table in the LUT 804, the image data is transferred from the DRAM 116 to the color space conversion unit 803 via the bus controller 113 to convert the monochrome halftone binary color space. The image binarization unit 805 performs multi-value-to-binary conversion, and then stores it again in the DRAM 116. Thereafter, the image data on the DRAM 116 that has been subjected to the monochrome halftone binary image processing is MMR-compressed on the DRAM 1163 (step S1509).
[0098]
On the other hand, if the CPU 112 determines that neither of the above formulas 1 and 2 is satisfied (NO in step S1507), the color space is used to create a monochrome multi-value image file from the image data stored in the DRAM 116. A monochrome multi-value parameter is set in the conversion unit 803, a black-and-white multi-value image generation table is set in the LUT 804, and then image data is transferred from the DRAM 116 to the color space conversion unit 803 via the bus controller 113. Multi-value color space conversion is performed and stored in the DRAM 116 again. Thereafter, the image data on the DRAM 116 that has been subjected to the monochrome multi-value image processing is JPEG-compressed on the DRAM 116 (step S1508).
[0099]
Then, the CPU 112 sends the image data subjected to the predetermined conversion in the above-described steps S1508 to S1511 from the DRAM 116 to the I / O control unit 126 via the bus controller 113, and is connected to the I / O control unit 126 by the connector 161. The data is transferred and stored in the HD 162 via the connected HD drive 160 (step S1512).
[0100]
As described above, according to the present embodiment, the original is read by the original reading unit of the image input / output device, the characteristics of the original are extracted based on the image data of the read original, and the image is displayed according to the characteristics of the original. Data color space conversion, multi-value binary conversion, compression format, and the like can be switched to convert the data into an optimal image format for the read document.
[0101]
Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), it is applied to an apparatus (for example, a copier, a facsimile machine, etc.) composed of a single device. It may be applied.
[0102]
Another object of the present invention is to supply a recording medium in which a program code of software realizing the functions of the above-described embodiments is recorded to a system or apparatus, and the computer (CPU or MPU) of the system or apparatus stores the recording medium in the recording medium. Needless to say, this can also be achieved by reading and executing the programmed program code.
[0103]
In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiment, and the recording medium storing the program code constitutes the present invention.
[0104]
As a recording medium for supplying the program code, for example, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like is used. be able to.
[0105]
Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.
[0106]
Further, after the program code read from the recording medium is written in a memory provided in a function expansion board 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 board or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.
[0107]
【The invention's effect】
As described above, according to the present invention, the image data can be converted into image data having the optimum gradation and compression format without performing complicated work by the user.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an overall configuration of an image input / output system according to an embodiment.
FIG. 2 is a side sectional view of a reader unit 200 and a printer unit 300. FIG.
3 is a block diagram showing a detailed configuration of a reader image processing unit 222. FIG.
4 is a block diagram showing a configuration of a control device 110. FIG.
FIG. 5 is a block diagram showing a detailed configuration of a portion responsible for scanner image processing.
FIG. 6 is a diagram illustrating a configuration of an ACS (auto color select) count unit 503;
FIG. 7 is a block diagram illustrating a detailed configuration of image processing of the printer I / F.
FIG. 8 is a block diagram showing a detailed configuration of the graphic processor 135. FIG.
FIG. 9 is a diagram for explaining image transfer in the image rotation unit 801;
10 is a diagram for explaining image rotation in an image rotation unit 801. FIG.
FIG. 11 is a flowchart illustrating a procedure for outputting a PDL image in the present embodiment.
FIG. 12 is a flowchart showing a copy image output procedure in the embodiment.
13 is a block diagram showing a detailed configuration of a scanner I / F 140. FIG.
FIG. 14 is a block diagram for explaining conversion processing in the present embodiment;
FIG. 15 is a flowchart showing conversion processing in the present embodiment.

Claims (8)

A format conversion method for converting the image format of the original according to the characteristics of the original read by the original reading means,
Extracting the features of the document based on the image data of the document read by the document reading means;
And a step of converting the image format of the image data in accordance with the characteristics of the extracted document. 2. The format conversion method according to claim 1, further comprising a step of storing the image data in which the image format has been converted in a storage means. 3. The format conversion method according to claim 2, wherein the extracting step determines whether the image data includes a character portion or a chromatic color, and extracts the feature of the document according to the determination result. . If the image data contains chromatic colors, it will be a color multivalued document. If the image data does not contain chromatic colors and contains more than a predetermined character part, it will be a simple binary document. 4. The format conversion method according to claim 3, wherein the format conversion method is a tone binary document, and otherwise a black and white multivalue document. The converting step includes color space conversion and JPEG compression for color when the document features are multi-valued, and color space conversion and MMR compression for simple binary when the binary is simple binary. In the case of binary tone, spatial conversion and MMR compression for halftone binary are performed. In the case of monochrome multi-value, color space conversion for monochrome multi-value and JPEG compression are performed to convert the image format of the image data. 5. The format conversion method according to claim 4, wherein An image processing apparatus that converts an image format of a document according to characteristics of the document read by a document reading unit,
Extraction means for extracting features of the original document based on image data of the original document read by the original reading means;
Conversion means for converting the image format of the image data according to the characteristics of the extracted document;
An image processing apparatus comprising storage means for storing image data obtained by converting the image format. A program for causing a computer to execute each procedure of the format conversion method according to claim 1. A computer-readable recording medium on which the program according to claim 7 is recorded.

Images