JP4000255B2 - Binarization pattern creation method, printing apparatus, and binarization pattern creation program - Google Patents

Description

となる。
ここで、
【００７９】
【数２】

なので、
【００８０】
【数３】

とすると、
【００８１】
【数４】

となる。
【００８２】
ただし、ｉ，ｊは、ともに整数である必要があるので、ｇｃｄ（ｊｄ，ｂ）＝ｂ，ｇｃｄ（ｉｂ，ｄ）＝ｄでなければならない。
なぜなら、ｉｂ−ｊｄ＝０より、
ｉ＝−ｊｄ／ｂ
ｉが整数であり、
ｊｄ＞ｂかつｊｄをｂで割った余りが０
よって、ｊｄとｂとの最大公約数はｂとならざるを得ないことになる。
【００８３】
同様に、ｉｂ＋ｊｄ＝０より
ｊ＝−ｉｂ／ｄ
ｊが整数（正／負を問わない）であり、
ｉｂ＞ｄかつｉｂをｄで割った割った余りが０
よって、ｉｂとｄとの最大公約数はｄとなる。
これらのことを考え併せると、ｎ／ｂとｎ／ｄとが共に整数となる範囲で、
【００８４】
【数５】

の形の最小値を求めることになるので、求める最小値は
【００８５】
【数６】

で与えられる。
また、ｙ方向についても同様であるので、結局パラメータ（ａ，ｂ，ｃ，ｄ）で指定される基本パターンと同一の二値化を実現する二値化用パターンであって、最小の矩形状パターンの副走査方向のサイズ（ピクセル数）は、
【００８６】
【数７】

となる。同様に、この最小の矩形状パターンの主走査方向のサイズ（ピクセル数）は、
【００８７】
【数８】

となる。
例えば、パラメータ（ａ，ｂ，ｃ，ｄ）＝（５，２，２，４）の基本パターンにおいては、副走査方向サイズ＝H, 主走査方向サイズ＝Vとする時、
【００８８】
【数９】

となる。
また、（７，２，４，８）のパターンでは，
【００８９】
【数１０】

となる。
なお、矩形状パターン作成部３０は、前述の式（３）および式（４）を用いて算出した所定サイズの矩形状パターンを切り出して形成した矩形状パターンにおいて、この矩形状パターンの特徴を有する部分パターンを矩形状パターンから切り出し、この部分パターンにより該矩形状パターンを代表させてもよい。
【００９０】
このとき、矩形状パターン作成部３０は、主走査方向サイズＹで且つ副走査方向サイズｉの、Ｙ×ｉ個のピクセルから成る矩形状の領域を部分パターンとして切り出す。
ここで、この部分パターンの主走査方向サイズＹは、特定サイズとして与えられた、矩形状パターンの主走査方向サイズであり、又、その副走査方向サイズｉは、領域が、一つの基本パターンに含まれる全種類の点灯順値（点灯順序決定部２０により、基本パターンを構成する全ピクセルに対してそれぞれ決定された点灯順序を示す数値）をそれぞれ付与されたピクセルを含むために必要な、最小の副走査方向サイズ（ピクセル数）である。
【００９１】
ここで、矩形状パターン作成部３０が部分パターンを切り出す手法を図１７に示すフローチャート（ステップＥ１０〜Ｅ５０）に従って説明する。
矩形状パターン作成部３０は、カウンタｍの値に１を入力した後（ステップＥ１０）、矩形状パターンにおいて、その始点から、主走査方向にｍ列分のピクセル（（Ｙ×ｍ）個のピクセル）によって形成される矩形領域を切り出す（ステップＥ２０）。
【００９２】
そして、矩形状パターン作成部３０は、この（Ｙ×ｍ）個のピクセル中に基本パターンにおける全ての点灯順値（１〜ｎ）が、それぞれ少なくとも１個以上存在しているか否かを判断し、（ステップＥ３０）、存在していない場合には（ステップＥ３０のＮＯルート参照）、ｍをインクリメントして（ステップＥ５０）、ステップＥ２０に戻る。
【００９３】
この（Ｙ×ｍ）個のピクセル中に基本パターンにおける全ての点灯順値が、それぞれ少なくとも１個以上存在している場合には（ステップＥ３０のＹＥＳルート参照）、次に、この（Ｙ×ｍ）個のピクセル中に基本パターンに、基本パターンにおける全ての点灯順値が、それぞれｉ個づつ存在しているか否かを判断する（ステップＥ４０）。
【００９４】
そして、矩形状パターン作成部３０は、この（Ｙ×ｍ）個のピクセル中に基本パターンに、基本パターンにおける全ての点灯順値がそれぞれｉ個づつ存在していない場合には（ステップＥ４０のＮＯルート参照）、ステップＥ５０に移行する。又、この（Ｙ×ｍ）個のピクセル中に基本パターンに、基本パターンにおける全ての点灯順値がｉ個づつ存在している場合には（ステップＥ４０のＹＥＳルート参照）、処理を終了する。
【００９５】
このようにして形成した部分パターンを記憶装置５５やＲＡＭ５３に保存しておき、二値化を行なうに際して、この部分パターンを参照位置をずらしながら連続的に用いることにより、二値化処理を行なうことができる。
図１８は部分パターンの例を示す図であって、Ｙ＝ｎ＝１７，ｉ＝１である場合の例を示す図である。
【００９６】
例えば、この図１８に示す部分パターン（上から３，１１，６，４・・・，２，１）の場合では、この部分パターンを１４づつずらしながら参照することにより（例えば、次の行は７，１０，２，・・・，１４，８，５）二値化処理を行なうことができる。
なお、この図１８に示す例は、Ｙ＝ｎの場合についてのものであるが、それに限定するものではなく、Ｙがｎ以外の数値であってもよく、本発明の趣旨を逸脱しない範囲で種々変形して実施することができる。
【００９７】
このような構成により、二値化用パターン作成装置１は、本発明の一実施形態としての二値化用パターン作成方法を用いて二値化用パターンを作成する。本発明の一実施形態としての二値化用パターン作成方法を図１９に示すフローチャート（ステップＦ１０〜Ｆ３０）に従って説明する。
まず、基本パターン形状作成部１０が、指定された網点ドット角度（θ）や階調数（ｎ）に基づいて基本パターン形状を作成する（ステップＦ１０）。その後、点灯順序決定部２０が、この基本パターンを構成する各ピクセルと特定点（例えば基本パターンの重心や中心）との距離に基づいて、これらの各ピクセルに点灯順序を決定する（ステップＦ２０）。なお、この際、各ピクセルと特定点との間に扁平率を設定してもよい。
【００９８】
そして、矩形状パターン作成部３０が、基本パターンを画像の主走査方向および副走査方向に繰り返し配置した連続パターンから、上記式（３）および式（４）を用いて算出した所定サイズの矩形状パターンを二値化用パターンとして切り出す（ステップＦ３０）。なお、このようにして形成した矩形状パターンから、特徴的な部分を切り出して使用してもよい。
【００９９】
さて、印刷装置は、上述の如く形成された二値化用パターンに基づいて媒体（用紙等）上に画像を形成するものであって、例えばインクジェットプリンタやレーザプリンタ等のプリンタ等によって実現される。
そして、この印刷装置においては、例えば、インクジェット機構やレーザダイオードユニットおよび感光体ドラム等が媒体上に画像を形成する画像形成部として機能するようになっている。
【０１００】
また、印刷装置内にそなえられたプロセッサ等が、二値化用パターンに基づいて二値化を行なう二値化処理部として機能してもよく、又、印刷システムにおいて、印刷装置（プリンタ）が接続されるコンピュータがこの二値化処理部として機能してもよく、本発明の趣旨を逸脱しない範囲で種々変形させることができる。
【０１０１】
これらの印刷装置もしくは印刷システムにおいては、二値化処理部において、上述の如く作成された二値化用パターンに基づいて多値画像の二値化を行なうことにより、媒体上における色材のＯＮ／ＯＦＦを決定する。
そして、画像形成部が、この二値化処理の結果に基づいて、媒体上に色材を乗せることにより画像が形成される。
【０１０２】
このように、本発明の一実施形態としての二値化用パターン作成装置１によれば、基本パターン形状の作成，点灯順序の設定および矩形状パターンの形成の各行程において、数式に基づいて自動的に処理することができるので、二値化用パターンを容易に作成することができる。従って、二値化用パターンの作成に際して操作者が熟練していなくとも、簡便に短時間にディザパターンを作成することができる。
【０１０３】
基本パターン形状作成部１０が、二値化用パターンの角度を指定し、基本パターンを構成するピクセル数を指定し、これらの指定した角度とピクセル数とに基づいて、基本パターン形状を演算により作成するので、所望の角度とピクセル数とをそなえる基本パターン形状を容易に作成することができる。
また、点灯順序決定部２０が、ピクセルと基本パターン中の特定点（中心や重心）との距離に基づいて、ピクセルの点灯順序を決定するので、容易に集中型の二値化用パターンを作成することができる。
【０１０４】
さらに、点灯順序決定部２０が、ピクセルと基本パターン中の特定点との距離と、その距離に関与する一定の係数（扁平率）とに基づいて、ピクセルの点灯順序を決定することにより、網点ドットの角度を保持した状態で、網点ドットの形状を円形状から楕円形状まで滑らかに変化させることができ、ドットずれやモアレを目立たなくさせることができる二値化用パターンを少ない工数で確実に作成することができる。
【０１０５】
またさらに、点灯順序決定部２０が、点灯順序を、基本パターンの特定点に近いピクセルから順に設定することにより、色材定着性能が不安定なプリンタにおいても確実に色を載せることができる。
そして、点灯ピクセルと非点灯ピクセルとの境界輪郭線の長さが最小になるように決定することにより、ドットゲインが小さくなり、印刷媒体への色材ののりが安定し出力品質が向上する。
【０１０６】
さらにまた、矩形状パターン作成部３０が、画像の主走査方向および副走査方向に基本パターンを繰り返し配列して形成した連続パターンから、特定サイズの矩形状パターンを二値化用パターンとして切り出して作成することにより、容易に矩形の二値化用パターンを作成することができる。
また、矩形状パターン作成部３０が、矩形状パターンの特徴を有する部分パターンを、矩形状パターンから切り出し、この部分パターンにより矩形状パターンを代表させることにより、二値化処理に際して二値化用パターンを展開するために要するメモリ領域（ＲＡＭ５３等）や、二値化用パターンの保存のための領域（ＲＯＭ５４，記憶装置５５等）を小さくすることができ、処理速度を向上させることができるほかハードウェアの製造コストを低減することができる。
【０１０７】
さらに、本発明の二値化用パターン作成方法によって作成される二値化用パターンが、矩形状パターンの特徴を有する部分パターンであって、この部分パターンが、主走査方向サイズＹで且つ副走査方向サイズｉの、Ｙ×ｉ個のピクセルから成る矩形状の領域であり、主走査方向サイズＹは、特定サイズとして与えられた矩形状パターンの主走査方向サイズであり、副走査方向サイズｉは、領域が、一つの基本パターンに含まれる全種類の点灯順値（点灯順序決定ステップＦ２０において、基本パターンを構成する全ピクセルに対してそれぞれ決定された点灯順序を示す数値）をそれぞれ付与されたピクセルを含むために必要な、最小の副走査方向サイズ（ピクセル数）であるので、二値化用パターンのサイズを小さくすることができるので、二値化に要するメモリ領域や二値化用パターンの保存のための領域を小さくすることができ、処理速度を向上させることができるほかハードウェアの製造コストを低減することができる。
【０１０８】
また、基本パターンの形状を、指定されたピクセル数ｎ＝ａｄ＋ｂｃの条件を満たす任意のパラメータａ，ｂ，ｃ，ｄ（ただし、ａ，ｂ，ｃ，ｄは整数）によって指定される、点Ａ（ｃ，１），点Ｂ（ａ＋ｃ，ｂ＋１），点Ｃ（０，ｄ＋１），点Ｄ（ａ，ｂ＋ｄ＋１）の４点からなる四角形として作成し、この作成された四角形のうち、その角度が指定された二値化用パターンの角度に近い角度を有するものを基本パターンとして選択することにより、基本パターンの形状を簡易に作成することができ、これにより、二値化用パターンを容易に作成することができる。
【０１０９】
さらに、基本パターン中におけるピクセルと特定点との距離に応じて、ピクセル毎に演算によって設定された重みに基づいて点灯順序を決定することにより、点灯順序を容易に設定することができ、これによっても、二値化用パターンを容易に作成することができる。
また、矩形状パターンを、この矩形状パターンの副走査方向Ｘのサイズｓｉｚｅ（ｘ）が、
ｓｉｚｅ（Ｘ）＝max（（ｎ÷gcd（ｂ，ｎ），（ｎ÷gcd（ｄ，ｎ））
であり、矩形状パターンの主走査方向Ｙのサイズｓｉｚｅ（Ｙ）が、
ｓｉｚｅ（Ｙ）＝max（（ｎ÷gcd（ａ，ｎ），（ｎ÷gcd（ｃ，ｎ））
となるように演算により作成することにより、矩形状パターンを容易に作成することができ、これによっても、二値化用パターンを容易に作成することができる。
【０１１０】
また、上述の如き二値化用パターンに基づいて二値化を行なう印刷システムもしくは印刷装置（プリンタ等）においては、ドットずれやモアレが目立たない高品質な印刷を行なうことができる。
（Ｂ）その他
本発明は上述した実施形態に限定されるものではなく、本発明の趣旨を逸脱しない範囲で種々変形して実施することができる。
【０１１１】
例えば、上述した実施形態においては、基本パターンを−θ回転させ、この回転させた基本パターンに対して点灯順序を設定しているが、それに限定されるものではなく、基本パターンを回転させることなく直接点灯順序を設定してもよい。
また、上述した実施形態においては、点灯順序決定部２０は、基本パターンを、中心点（特定点）を含む水平線を境に上下に２分割して、これらの上半分のピクセルと下半分のピクセルとに対して、交互に重み（Ｗ）の大きいものから順番に点灯順序を設定しているが、これに限定されるものではなく、例えば、基本パターンを特定点を含む鉛直線を境に左右に２分割して、これらの右半分のピクセルと左半分のピクセルとに対して、交互に重み（Ｗ）の大きいものから順番に点灯順序を設定してもよい。
【０１１２】
さらに、上述した実施形態においては、点灯順序決定部２０は、基本パターンを−θ回転させた後に、この回転させた基本パターンに対して重み（Ｗ）を計算して点灯順序を決定しているが、それに限定されるものではない。
図２０（ａ），（ｂ）は基本パターンを−θ回転させずに点灯順序の設定する手法を説明するための図であり、図２０（ａ）は点灯順序の設定を途中まで行なった状態を示す図、図２０（ｂ）は基本パターンに点灯順序を設定した状態を示す図である。
【０１１３】
この図２０（ａ），（ｂ）に示すように、点灯順序設定部２０は、基本パターンを−θ回転させることなく、各ピクセルの重み（Ｗ）を計算して点灯順序を設定してもよい。
なお、本発明の各実施形態が開示されていれば、当業者によって製造することが可能である。
【０１１４】
（Ｃ）付記
（付記１） 多値画像の二値化に用いられる二値化用パターンの作成方法であって、
該二値化用パターンの基本パターンの形状を演算により作成する基本パターン形状作成ステップと、
該基本パターンを構成するピクセルの点灯順序を決定する点灯順序決定ステップと、
該基本パターンに基づいて、該二値化用パターンとして機能する矩形状パターンを作成する矩形状パターン作成ステップとをそなえることを特徴とする、二値化用パターン作成方法。
【０１１５】
（付記２） 多値画像の二値化に用いられる二値化用パターンの作成方法であって、
該二値化用パターンの基本パターンの形状を作成する基本パターン形状作成ステップと、
該基本パターンを構成するピクセルの点灯順序を演算により決定する点灯順序決定ステップと、
該基本パターンに基づいて、該二値化用パターンとして機能する矩形状パターンを作成する矩形状パターン作成ステップとをそなえることを特徴とする、二値化用パターン作成方法。
【０１１６】
（付記３） 多値画像の二値化に用いられる二値化用パターンの作成方法であって、
該二値化用パターンの基本パターンの形状を演算により作成する基本パターン形状作成ステップと、
該基本パターンを構成するピクセルの点灯順序を演算により決定する点灯順序決定ステップと、
該基本パターンに基づいて、該二値化用パターンとして機能する矩形状パターンを作成する矩形状パターン作成ステップとをそなえることを特徴とする、二値化用パターン作成方法。
【０１１７】
（付記４） 該矩形状パターン作成ステップにおいて、該矩形状パターンを演算により作成することを特徴とする、付記１〜付記３のいずれか１項に記載の二値化用パターン作成方法。
（付記５） 該基本パターン形状作成ステップにおいて、
該二値化用パターンの角度を指定する角度指定ステップと、
該基本パターンを構成するピクセル数を指定するピクセル数指定ステップと、該角度指定ステップにおいて指定した該角度と該ピクセル数指定ステップにおいて指定した該ピクセル数とに基づいて、該基本パターン形状を演算により作成する演算ステップとをそなえることを特徴とする、付記１〜付記４のいずれか１項に記載の二値化用パターン作成方法。
【０１１８】
（付記６） 該基本パターン形状作成ステップにおいて、該基本パターンの形状を、該ピクセル数指定ステップにおいて指定した該ピクセル数ｎ＝ａｄ＋ｂｃの条件を満たす任意のパラメータａ，ｂ，ｃ，ｄ（ただし、ａ，ｂ，ｃ，ｄは整数）によって指定される、点Ａ（ｃ，１），点Ｂ（ａ＋ｃ，ｂ＋１），Ｃ（０，ｄ＋１），Ｄ（ａ，ｂ＋ｄ＋１）の４点からなる四角形として作成し、当該作成された四角形のうち、その角度が該角度指定ステップにおいて指定された該二値化用パターンの角度に近い角度を有するものを該基本パターンとして選択することを特徴とする、付記５記載の二値化用パターン作成方法。
【０１１９】
（付記７） 該点灯順序決定ステップにおいて、
当該ピクセルと該基本パターン中の特定点との距離に基づいて、該ピクセルの点灯順序を決定することを特徴とする、付記１〜付記６のいずれか１項に記載の二値化用パターン作成方法。
（付記８） 該点灯順序決定ステップにおいて、
該点灯順序を、該基本パターンの特定点に近い該ピクセルから順に、且つ、点灯ピクセルと非点灯ピクセルとの境界輪郭線の長さが最小になるように決定することを特徴とする、付記７記載の二値化用パターン作成方法。
【０１２０】
（付記９） 該点灯順序決定ステップにおいて、
当該ピクセルと該基本パターン中の特定点との距離に関与する一定の係数に基づいて、該ピクセルの点灯順序を決定することを特徴とする、付記７又は付記８記載の二値化用パターン作成方法。
（付記１０） 該点灯順序決定ステップにおいて、該点灯順序を、該基本パターン中における該ピクセルと特定点との距離に応じて、該ピクセル毎に演算によって設定された重みに基づいて決定することを特徴とする、付記２又は付記３記載の二値化用パターン作成方法。
【０１２１】
（付記１１） 該矩形状パターン作成ステップにおいて、
画像の主走査方向および副走査方向に該基本パターンを繰り返し配列して形成した連続パターンから、特定サイズの該矩形状パターンを該二値化用パターンとして切り出して作成することを特徴とする、付記１〜付記１０のいずれか１項に記載の二値化用パターン作成方法。
【０１２２】
（付記１２） 該矩形状パターン作成ステップにおいて、
該矩形状パターンの特徴を有する部分パターンを、該矩形状パターンから切り出し、該部分パターンにより該矩形状パターンを代表させることを特徴とする、付記１１記載の二値化用パターン作成方法。
（付記１３） 該部分パターンは、主走査方向サイズＹで且つ副走査方向サイズｉの、Ｙ×ｉ個のピクセルから成る、矩形状の領域であり、
前記主走査方向サイズＹは、前記特定サイズとして与えられた、該矩形状パターンの主走査方向サイズであり、
前記副走査方向サイズｉは、該領域が、一つの基本パターンに含まれる全種類の点灯順値（該点灯順序決定ステップにおいて、該基本パターンを構成する全ピクセルに対してそれぞれ決定された点灯順序を示す数値）をそれぞれ付与されたピクセルを含むために必要な、最小の副走査方向サイズ（ピクセル数）であることを特徴とする、付記１２記載の二値化用パターン作成方法。
【０１２３】
（付記１４） 該矩形状パターン作成ステップにおいて、該矩形状パターンを、当該矩形状パターンの副走査方向Ｘのサイズｓｉｚｅ（ｘ）が、
ｓｉｚｅ（Ｘ）＝max（（ｎ÷gcd（ｂ，ｎ），（ｎ÷gcd（ｄ，ｎ））
であり、当該矩形状パターンの主走査方向Ｙのサイズｓｉｚｅ（Ｙ）が、
ｓｉｚｅ（Ｙ）＝max（（ｎ÷gcd（ａ，ｎ），（ｎ÷gcd（ｃ，ｎ））
となるように演算により作成することを特徴とする、付記６記載の二値化用パターン作成方法。
【０１２４】
（付記１５） 基本パターンに基づいて作成され、多値画像の二値化に用いられる二値化用パターンであって、
該基本パターンを構成するピクセルのうち、該基本パターンの特定点に近いピクセルから順に、且つ、点灯ピクセルと非点灯ピクセルとの境界輪郭線の長さが最小になるように、該ピクセルを点灯させることによって、連続的な網点ドットを生成することを特徴とする、二値化用パターン。
【０１２５】
（付記１６） 該ピクセルと該基本パターン中の特定点との距離に関与する一定の係数に基づいて、該ピクセルの点灯順序が決定されたことを特徴とする、付記１５記載の二値化用パターン。
（付記１７） 基本パターンに基づいて作成され、多値画像の二値化に用いられる、矩形状の二値化用パターンであって、
該二値化用パターンの特徴を有する部分パターンの各ピクセルを、所定の点灯順序で点灯させるとともに、該部分パターンを所定規則に従って繰り返し配置することによって、連続的な網点ドットを生成することを特徴とする、二値化用パターン。
【０１２６】
（付記１８） 該部分パターンは、主走査方向サイズＹで且つ副走査方向サイズｉの、Ｙ×ｉ個のピクセルから成る、矩形状の領域であり、
前記主走査方向サイズＹは、前記特定サイズとして与えられた、該二値化用パターンの主走査方向サイズであり、
前記副走査方向サイズｉは、該領域が、一つの基本パターンに含まれる全種類の点灯順値（該基本パターンを構成する全ピクセルに対してそれぞれ決定された点灯順序を示す数値）をそれぞれ付与されたピクセルを含むために必要な、最小の副走査方向サイズ（ピクセル数）であることを特徴とする、付記１７記載の二値化用パターン。
【０１２７】
（付記１９） 多値画像の二値化に用いられる二値化用パターンを作成する二値化用パターン作成装置であって、
該二値化用パターンの基本パターンの形状を演算により作成する基本パターン形状作成部と、
該基本パターンを構成するピクセルの点灯順序を演算により決定する点灯順序決定部と、
該基本パターンに基づいて、該二値化用パターンとして機能する矩形状パターンを演算により作成する矩形状パターン作成部とをそなえることを特徴とする、二値化用パターン作成装置。
【０１２８】
（付記２０） 該基本パターン形状作成部が、
該二値化用パターンの角度を指定する角度指定部と、
該基本パターンを構成するピクセル数を指定するピクセル数指定部と、
該角度指定部が指定した該角度と該ピクセル数指定部が指定した該ピクセル数とに基づいて、該基本パターン形状を演算により作成する演算部とをそなえることを特徴とする、付記１９記載の二値化用パターン作成装置。
【０１２９】
（付記２１） 該基本パターン形状作成部が、該基本パターンの形状を、該ピクセル数指定部により指定された該ピクセル数ｎ＝ａｄ＋ｂｃの条件を満たす任意のパラメータａ，ｂ，ｃ，ｄ（ただし、ａ，ｂ，ｃ，ｄは整数）によって指定される、点Ａ（ｃ，１），点Ｂ（ａ＋ｃ，ｂ＋１），Ｃ（０，ｄ＋１），Ｄ（ａ，ｂ＋ｄ＋１）の４点からなる四角形として作成し、当該作成された四角形のうち、その角度が該角度指定部によって指定された該二値化用パターンの角度に近い角度を有するものを該基本パターンとして選択することを特徴とする、付記２０記載の二値化用パターン作成装置。
【０１３０】
（付記２２） 該点灯順序決定部が、
当該ピクセルと該基本パターン中の特定点との距離に基づいて、該ピクセルの点灯順序を決定することを特徴とする、付記１９〜付記２１のいずれか１項に記載の二値化用パターン作成装置。
（付記２３） 該点灯順序決定部が、
該点灯順序を、該基本パターンの特定点に近い該ピクセルから順に、且つ、点灯ピクセルと非点灯ピクセルとの境界輪郭線の長さが最小になるように決定することを特徴とする、付記２２記載の二値化用パターン作成装置。
【０１３１】
（付記２４） 該点灯順序決定部が、
当該ピクセルと該基本パターン中の特定点との距離に関与する一定の係数に基づいて、該ピクセルの点灯順序を決定することを特徴とする、付記２２又は付記２３記載の二値化用パターン作成装置。
（付記２５） 該矩形状パターン作成部が、
画像の主走査方向および副走査方向に該基本パターンを繰り返し配列して形成した連続パターンから、特定サイズの該矩形状パターンを該二値化用パターンとして切り出すことを特徴とする、付記１９〜付記２４のいずれか１項に記載の二値化用パターン作成装置。
【０１３２】
（付記２６） 該矩形状パターン作成部が、
該矩形状パターンの特徴を有する部分パターンを、該矩形状パターンから切り出し、該部分パターンにより該矩形状パターンを代表させることを特徴とする、付記２５記載の二値化用パターン作成装置。
（付記２７） 該部分パターンは、主走査方向サイズＹで且つ副走査方向サイズｉの、Ｙ×ｉ個のピクセルから成る、矩形状の領域であり、
前記主走査方向サイズＹは、前記特定サイズとして与えられた、該矩形状パターンの主走査方向サイズであり、
前記副走査方向サイズｉは、該領域が、一つの基本パターンに含まれる全種類の点灯順値（該点灯順序決定部により、該基本パターンを構成する全ピクセルに対してそれぞれ決定された点灯順序を示す数値）をそれぞれ付与されたピクセルを含むために必要な、最小の副走査方向サイズ（ピクセル数）であることを特徴とする、付記２６記載の二値化用パターン作成装置。
【０１３３】
（付記２８） 該矩形状パターン作成部が、該矩形状パターンを、当該矩形状パターンの副走査方向Ｘのサイズｓｉｚｅ（ｘ）が、
ｓｉｚｅ（Ｘ）＝max（（ｎ÷gcd（ｂ，ｎ），（ｎ÷gcd（ｄ，ｎ））
であり、当該矩形状パターンの主走査方向Ｙのサイズｓｉｚｅ（Ｙ）が、
ｓｉｚｅ（Ｙ）＝max（（ｎ÷gcd（ａ，ｎ），（ｎ÷gcd（ｃ，ｎ））
となるように演算により作成することを特徴とする、付記２１記載の二値化用パターン作成装置。
【０１３４】
（付記２９） 多値画像の二値化に用いられる二値化用パターンの作成機能をコンピュータに実行させるための二値化用パターン作成プログラムであって、
該二値化用パターンの基本パターンの形状を演算により作成する基本パターン形状作成部と、
該基本パターンを構成するピクセルの点灯順序を演算により決定する点灯順序決定部と、
該基本パターンに基づいて、該二値化用パターンとして機能する矩形状パターンを演算により作成する矩形状パターン作成部として、該コンピュータを機能させることを特徴とする、二値化用パターン作成プログラム。
【０１３５】
（付記３０） 該基本パターン形状作成部が、
該二値化用パターンの角度を指定する角度指定部と、
該基本パターンを構成するピクセル数を指定するピクセル数指定部と、
該角度指定部が指定した該角度と該ピクセル数指定部が指定した該ピクセル数とに基づいて、該基本パターン形状を演算により作成する演算部とをそなえることを特徴とする、付記２９記載の二値化用パターン作成プログラム。
【０１３６】
（付記３１） 該基本パターン形状作成部が、該基本パターンの形状を、該ピクセル数指定部により指定された該ピクセル数ｎ＝ａｄ＋ｂｃの条件を満たす任意のパラメータａ，ｂ，ｃ，ｄ（ただし、ａ，ｂ，ｃ，ｄは整数）によって指定される、点Ａ（ｃ，１），点Ｂ（ａ＋ｃ，ｂ＋１），Ｃ（０，ｄ＋１），Ｄ（ａ，ｂ＋ｄ＋１）の４点からなる四角形として作成し、当該作成された四角形のうち、その角度が該角度指定部によって指定された該二値化用パターンの角度に近い角度を有するものを該基本パターンとして選択することを特徴とする、付記３０記載の二値化用パターン作成プログラム。
【０１３７】
（付記３２） 該点灯順序決定部が、
当該ピクセルと該基本パターン中の特定点との距離に基づいて、該ピクセルの点灯順序を決定することを特徴とする、付記２９〜付記３１のいずれか１項に記載の二値化用パターン作成プログラム。
（付記３３） 該点灯順序決定部が、
該点灯順序を、該基本パターンの特定点に近い該ピクセルから順に、且つ、点灯ピクセルと非点灯ピクセルとの境界輪郭線の長さが最小になるように決定することを特徴とする、付記３２記載の二値化用パターン作成プログラム。
【０１３８】
（付記３４） 該点灯順序決定部が、
当該ピクセルと該基本パターン中の特定点との距離に関与する一定の係数に基づいて、該ピクセルの点灯順序を決定することを特徴とする、付記３２又は付記３３記載の二値化用パターン作成プログラム。
（付記３５） 該矩形状パターン作成部が、
画像の主走査方向および副走査方向に該基本パターンを繰り返し配列して形成した連続パターンから、特定サイズの該矩形状パターンを該二値化用パターンとして切り出すことを特徴とする、付記２９〜付記３４のいずれか１項に記載の二値化用パターン作成プログラム。
【０１３９】
（付記３６） 該矩形状パターン作成部が、
該矩形状パターンの特徴を有する部分パターンを、該矩形状パターンから切り出し、該部分パターンにより該矩形状パターンを代表させることを特徴とする、付記３５記載の二値化用パターン作成プログラム。
（付記３７） 該部分パターンは、主走査方向サイズＹで且つ副走査方向サイズｉの、Ｙ×ｉ個のピクセルから成る、矩形状の領域であり、
前記主走査方向サイズＹは、前記特定サイズとして与えられた、該矩形状パターンの主走査方向サイズであり、
前記副走査方向サイズｉは、該領域が、一つの基本パターンに含まれる全種類の点灯順値（該点灯順序決定部により、該基本パターンを構成する全ピクセルに対してそれぞれ決定された点灯順序を示す数値）をそれぞれ付与されたピクセルを含むために必要な、最小の副走査方向サイズ（ピクセル数）であることを特徴とする、付記３６記載の二値化用パターン作成プログラム。
【０１４０】
（付記３８） 該矩形状パターン作成部が、該矩形状パターンを、当該矩形状パターンの副走査方向Ｘのサイズｓｉｚｅ（ｘ）が、
ｓｉｚｅ（Ｘ）＝max（（ｎ÷gcd（ｂ，ｎ），（ｎ÷gcd（ｄ，ｎ））
であり、当該矩形状パターンの主走査方向Ｙのサイズｓｉｚｅ（Ｙ）が、
ｓｉｚｅ（Ｙ）＝max（（ｎ÷gcd（ａ，ｎ），（ｎ÷gcd（ｃ，ｎ））
となるように演算により作成することを特徴とする、付記３１記載の二値化用パターン作成プログラム。
【０１４１】
（付記３９） 多値画像の二値化に用いられる二値化用パターンの作成機能をコンピュータに実行させるための二値化用パターン作成プログラムを記録したコンピュータ読取可能な記録媒体であって、
該二値化用パターン作成プログラムが、
該二値化用パターンの基本パターンの形状を演算により作成する基本パターン形状作成部と、
該基本パターンを構成するピクセルの点灯順序を演算により決定する点灯順序決定部と、
該基本パターンに基づいて、該二値化用パターンとして機能する矩形状パターンを演算により作成する矩形状パターン作成部として、該コンピュータを機能させることを特徴とする、二値化用パターン作成プログラムを記録したコンピュータ読取可能な記録媒体。
【０１４２】
（付記４０） 該基本パターン形状作成部が、
該二値化用パターンの角度を指定する角度指定部と、
該基本パターンを構成するピクセル数を指定するピクセル数指定部と、
該角度指定部が指定した該角度と該ピクセル数指定部が指定した該ピクセル数とに基づいて、該基本パターン形状を演算により作成する演算部とをそなえることを特徴とする、付記３９記載の二値化用パターン作成プログラムを記録したコンピュータ読取可能な記録媒体。
【０１４３】
（付記４１） 該基本パターン形状作成部が、該基本パターンの形状を、該ピクセル数指定部により指定された該ピクセル数ｎ＝ａｄ＋ｂｃの条件を満たす任意のパラメータａ，ｂ，ｃ，ｄ（ただし、ａ，ｂ，ｃ，ｄは整数）によって指定される、点Ａ（ｃ，１），点Ｂ（ａ＋ｃ，ｂ＋１），Ｃ（０，ｄ＋１），Ｄ（ａ，ｂ＋ｄ＋１）の４点からなる四角形として作成し、当該作成された四角形のうち、その角度が該角度指定部によって指定された該二値化用パターンの角度に近い角度を有するものを該基本パターンとして選択することを特徴とする、付記４０記載の二値化用パターン作成プログラムを記録したコンピュータ読取可能な記録媒体。
【０１４４】
（付記４２） 該点灯順序決定部が、
当該ピクセルと該基本パターン中の特定点との距離に基づいて、該ピクセルの点灯順序を決定することを特徴とする、付記３９〜付記４１のいずれか１項に記載の二値化用パターン作成プログラムを記録したコンピュータ読取可能な記録媒体。
【０１４５】
（付記４３） 該点灯順序決定部が、
該点灯順序を、該基本パターンの特定点に近い該ピクセルから順に、且つ、点灯ピクセルと非点灯ピクセルとの境界輪郭線の長さが最小になるように決定することを特徴とする、付記４２記載の二値化用パターン作成プログラムを記録したコンピュータ読取可能な記録媒体。
【０１４６】
（付記４４） 該点灯順序決定部が、
当該ピクセルと該基本パターン中の特定点との距離に関与する一定の係数に基づいて、該ピクセルの点灯順序を決定することを特徴とする、付記４２又は付記４３記載の二値化用パターン作成プログラムを記録したコンピュータ読取可能な記録媒体。
【０１４７】
（付記４５） 該矩形状パターン作成部が、
画像の主走査方向および副走査方向に該基本パターンを繰り返し配列して形成した連続パターンから、特定サイズの該矩形状パターンを該二値化用パターンとして切り出すことを特徴とする、付記３９〜付記４４のいずれか１項に記載の二値化用パターン作成プログラムを記録したコンピュータ読取可能な記録媒体。
【０１４８】
（付記４６） 該矩形状パターン作成部が、
該矩形状パターンの特徴を有する部分パターンを、該矩形状パターンから切り出し、該部分パターンにより該矩形状パターンを代表させることを特徴とする、付記４５記載の二値化用パターン作成プログラムを記録したコンピュータ読取可能な記録媒体。
【０１４９】
（付記４７） 該部分パターンは、主走査方向サイズＹで且つ副走査方向サイズｉの、Ｙ×ｉ個のピクセルから成る、矩形状の領域であり、
前記主走査方向サイズＹは、前記特定サイズとして与えられた、該矩形状パターンの主走査方向サイズであり、
前記副走査方向サイズｉは、該領域が、一つの基本パターンに含まれる全種類の点灯順値（該点灯順序決定部により、該基本パターンを構成する全ピクセルに対してそれぞれ決定された点灯順序を示す数値）をそれぞれ付与されたピクセルを含むために必要な、最小の副走査方向サイズ（ピクセル数）であることを特徴とする、付記４６記載の二値化用パターン作成プログラムを記録したコンピュータ読取可能な記録媒体。
【０１５０】
（付記４８） 該矩形状パターン作成部が、該矩形状パターンを、当該矩形状パターンの副走査方向Ｘのサイズｓｉｚｅ（ｘ）が、
ｓｉｚｅ（Ｘ）＝max（（ｎ÷gcd（ｂ，ｎ），（ｎ÷gcd（ｄ，ｎ））
であり、当該矩形状パターンの主走査方向Ｙのサイズｓｉｚｅ（Ｙ）が、
ｓｉｚｅ（Ｙ）＝max（（ｎ÷gcd（ａ，ｎ），（ｎ÷gcd（ｃ，ｎ））
となるように演算により作成することを特徴とする、付記４１記載の二値化用パターン作成プログラムを記録したコンピュータ読取可能な記録媒体。
【０１５１】
（付記４９） 二値化用パターンに基づいて、多値画像の二値化を行なう二値化処理部と、
該二値化処理部によって行なわれた二値化結果に基づいて、媒体上に画像を形成する画像形成部を有する印刷装置とをそなえ、
該二値化パターンが、
基本パターンに基づいて作成され、該基本パターンを構成するピクセルのうち、該基本パターンの特定点に近いピクセルから順に、且つ、点灯ピクセルと非点灯ピクセルとの境界輪郭線の長さが最小になるように、該ピクセルを点灯させることによって、連続的な網点ドットを生成することを特徴とする、印刷システム。
【０１５２】
（付記５０） 該二値化用パターンが、
該ピクセルと該基本パターン中の特定点との距離に関与する一定の係数に基づいて、該ピクセルの点灯順序が決定されたことを特徴とする、付記４９記載の印刷システム。
（付記５１） 二値化用パターンに基づいて、多値画像の二値化を行なう二値化処理部と、
該二値化処理部によって行なわれた二値化結果に基づいて、媒体上に画像を形成する画像形成部を有する印刷装置とをそなえ、
該二値化パターンが、
基本パターンに基づいて作成される、矩形状の二値化用パターンであって、
該二値化用パターンの特徴を有する部分パターンの各ピクセルを、所定の点灯順序で点灯させるとともに、該部分パターンを所定規則に従って繰り返し配置することによって、連続的な網点ドットを生成することを特徴とする、印刷システム。
【０１５３】
（付記５２） 該部分パターンは、主走査方向サイズＹで且つ副走査方向サイズｉの、Ｙ×ｉ個のピクセルから成る、矩形状の領域であり、
前記主走査方向サイズＹは、前記特定サイズとして与えられた、該二値化用パターンの主走査方向サイズであり、
前記副走査方向サイズｉは、該領域が、一つの基本パターンに含まれる全種類の点灯順値（該基本パターンを構成する全ピクセルに対してそれぞれ決定された点灯順序を示す数値）をそれぞれ付与されたピクセルを含むために必要な、最小の副走査方向サイズ（ピクセル数）であることを特徴とする、付記５１記載の印刷システム。
【０１５４】
（付記５３） 二値化用パターンに基づいて、多値画像の二値化を行なう二値化処理部と、
該二値化処理部によって行なわれた二値化結果に基づいて、媒体上に画像を形成する画像形成部とをそなえてなる印刷装置であって、
該二値化パターンが、
基本パターンに基づいて作成され、該基本パターンを構成するピクセルのうち、該基本パターンの特定点に近いピクセルから順に、且つ、点灯ピクセルと非点灯ピクセルとの境界輪郭線の長さが最小になるように、該ピクセルを点灯させることによって、連続的な網点ドットを生成することを特徴とする、印刷装置。
【０１５５】
（付記５４） 該二値化用パターンが、
該ピクセルと該基本パターン中の特定点との距離に関与する一定の係数に基づいて、該ピクセルの点灯順序が決定されたことを特徴とする、付記５３記載の印刷装置。
（付記５５） 二値化用パターンに基づいて、多値画像の二値化を行なう二値化処理部と、
該二値化処理部によって行なわれた二値化結果に基づいて、媒体上に画像を形成する画像形成部とをそなえてなる印刷装置であって、
該二値化パターンが、
基本パターンに基づいて作成される、矩形状の二値化用パターンであって、
該二値化用パターンの特徴を有する部分パターンの各ピクセルを、所定の点灯順序で点灯させるとともに、該部分パターンを所定規則に従って繰り返し配置することによって、連続的な網点ドットを生成することを特徴とする、印刷装置。
【０１５６】
（付記５６） 該部分パターンは、主走査方向サイズＹで且つ副走査方向サイズｉの、Ｙ×ｉ個のピクセルから成る、矩形状の領域であり、
前記主走査方向サイズＹは、前記特定サイズとして与えられた、該二値化用パターンの主走査方向サイズであり、
前記副走査方向サイズｉは、該領域が、一つの基本パターンに含まれる全種類の点灯順値（該基本パターンを構成する全ピクセルに対してそれぞれ決定された点灯順序を示す数値）をそれぞれ付与されたピクセルを含むために必要な、最小の副走査方向サイズ（ピクセル数）であることを特徴とする、付記５５記載の印刷装置。
【０１５７】
【発明の効果】
以上詳述したように、本発明の二値化用パターン作成方法，印刷装置および二値化用パターン作成プログラムによれば、以下の効果ないし利点がある。
（１）二値化用パターンの基本パターンの形状を演算により作成し、この基本パターンを構成するピクセルの点灯順序を決定し、基本パターンに基づいて、二値化用パターンとして機能する矩形状パターンを作成することにより二値化用パターンを作成するので、二値化用パターンを簡易に作成することができる（請求項１，請求項５）。
【０１５８】
（２）基本パターンの形状の作成に際して、二値化用パターンの角度を指定し、基本パターンを構成するピクセル数を指定し、これらの指定した角度とピクセル数とに基づいて、基本パターン形状を演算により作成するので、所望の角度とピクセル数とをそなえる基本パターン形状を容易に作成することができる（請求項１，請求項５）。
【０１５９】
（３）点灯順序を決定するに際して、ピクセルと基本パターン中の特定点との距離に基づいて、ピクセルの点灯順序を決定することにより、容易に集中型の二値化用パターンを作成することができる。
（４）点灯順序を決定するに際して、ピクセルと基本パターン中の特定点との距離と、その距離に関与する一定の係数とに基づいて、ピクセルの点灯順序を決定することにより、網点ドットの角度を保持した状態で、網点ドットの形状を円形状から楕円形状まで滑らかに変化させることができ、ドットずれやモアレを目立たなくさせることができる二値化用パターンを少ない工数で確実に作成することができる。
【０１６０】
（５）点灯順序を決定するに際して、点灯順序を、基本パターンの特定点に近いピクセルから順に、且つ、点灯ピクセルと非点灯ピクセルとの境界輪郭線の長さが最小になるように決定することにより、ドットゲインが小さくなり色材ののりが安定するので、出力品質が向上する（請求項３）。
（６）矩形状パターンの作成に際して、画像の主走査方向および副走査方向に基本パターンを繰り返し配列して形成した連続パターンから、特定サイズの矩形状パターンを二値化用パターンとして切り出して作成することにより、容易に矩形の二値化用パターンを作成することができる。
【０１６１】
（７）矩形状パターンの作成に際して、矩形状パターンの特徴を有する部分パターンを、矩形状パターンから切り出し、この部分パターンにより矩形状パターンを代表させることにより、二値化用パターンのサイズを小さくすることができるので、二値化に要するメモリ領域や二値化用パターンの保存のための領域を小さくすることができ、処理速度を向上させることができるほかハードウェアの製造コストを低減することができる（請求項４）。
【０１６２】
（８）部分パターンが、主走査方向サイズＹで且つ副走査方向サイズｉの、Ｙ×ｉ個のピクセルから成る矩形状の領域であり、主走査方向サイズＹは、特定サイズとして与えられた矩形状パターンの主走査方向サイズであり、副走査方向サイズｉは、領域が、一つの基本パターンに含まれる全種類の点灯順値（点灯順序決定ステップにおいて、基本パターンを構成する全ピクセルに対してそれぞれ決定された点灯順序を示す数値）をそれぞれ付与されたピクセルを含むために必要な、最小の副走査方向サイズ（ピクセル数）であるので、二値化用パターンのサイズを小さくすることができるので、二値化処理に際して二値化用パターンを展開するために要するメモリ領域や、二値化用パターンの保存のための領域を小さくすることができ、処理速度を向上させることができるほかハードウェアの製造コストを低減することができる。
【０１６３】
（９）基本パターンの形状を、指定されたピクセル数ｎ＝ａｄ＋ｂｃの条件を満たす任意のパラメータａ，ｂ，ｃ，ｄ（ただし、ａ，ｂ，ｃ，ｄは整数）によって指定される、点Ａ（ｃ，１），点Ｂ（ａ＋ｃ，ｂ＋１），点Ｃ（０，ｄ＋１），点Ｄ（ａ，ｂ＋ｄ＋１）の４点からなる四角形として作成し、この作成された四角形のうち、その角度が指定された二値化用パターンの角度に近い角度を有するものを基本パターンとして選択することにより、基本パターンの形状を簡易に作成することができ、これにより、二値化用パターンを容易に作成することができる（請求項１，請求項５）。
【０１６４】
（１０）基本パターン中におけるピクセルと特定点との距離に応じて、ピクセル毎に演算によって設定された重みに基づいて点灯順序を決定することにより、点灯順序を容易に設定することができ、これにより、二値化用パターンを容易に作成することができる。
（１１）矩形状パターンを、この矩形状パターンの副走査方向Ｘのサイズｓｉｚｅ（ｘ）が、
ｓｉｚｅ（Ｘ）＝max（（ｎ÷gcd（ｂ，ｎ），（ｎ÷gcd（ｄ，ｎ））
であり、矩形状パターンの主走査方向Ｙのサイズｓｉｚｅ（Ｙ）が、
ｓｉｚｅ（Ｙ）＝max（（ｎ÷gcd（ａ，ｎ），（ｎ÷gcd（ｃ，ｎ））
となるように演算により作成することにより、矩形状パターンを容易に作成することができ、これにより、二値化用パターンを容易に作成することができる（請求項２）。
【０１６５】
（１２）上述の如き二値化用パターンに基づいて二値化を行なう印刷システムもしくは印刷装置においては、ドットずれやモアレが目立たない高品質な印刷を行なうことができる。
【図面の簡単な説明】
【図１】本発明の一実施形態としての二値化用パターン作成方法を用いた二値化用パターン作成装置の機能ブロック図である。
【図２】本発明の一実施形態としての二値化用パターン作成方法を用いた二値化用パターン作成装置のハードウェア構成を示す図である。
【図３】一般的な多値画像の二値化処理の概念図である。
【図４】基本パターンの形状の例を示す図である。
【図５】（ａ）は四角形ＡＢＣＤの形状を座標値によって示す図、（ｂ）は四角形ＡＢＣＤをピクセルによって示す図である。
【図６】演算部による基本パターン形状の作成手法を説明するためのフローチャートである。
【図７】パラメータａ，ｂ，ｃ，ｄによって決定される四角形の網点ドットの角度と、予め指定された角度とを比較して示す例を示す図である。
【図８】ピクセルの点灯順序の例を示す図である。
【図９】点灯ピクセルと非点灯ピクセルとの境界輪郭線の長さが最小になるように点灯順序を設定した例を示す図である。
【図１０】点灯ピクセルと非点灯ピクセルとの境界輪郭線の長さが最小になるように点灯順序を設定しなかった例を示す図である。
【図１１】点灯順序決定部による点灯順序の決定手法を説明するためのフローチャートである。
【図１２】（ａ）は点灯順序の設定を途中まで行なった状態を示す図、（ｂ）は基本パターンを−θ回転させた状態を示す図、（ｃ）は基本パターンに点灯順序を設定した状態を示す図である。
【図１３】点灯順序決定部による点灯順序の他の決定手法を説明するためのフローチャートである。
【図１４】矩形状パターンの例を示す図である。
【図１５】矩形状パターン作成部による矩形状パターンの作成手法を説明するためのフローチャートである。
【図１６】（ａ）は矩形状パターンの証明に用いる基本パターンを説明するための図、（ｂ）は基本パターンを平面上に展開した例を示す図である。
【図１７】矩形状パターン作成部が部分パターンを切り出す手法を説明するためのフローチャートである。
【図１８】部分パターンの例を示す図である。
【図１９】本発明の一実施形態としての二値化用パターン作成方法を説明するためのフローチャートである。
【図２０】（ａ）は点灯順序の設定を途中まで行なった状態を示す図、（ｂ）は基本パターンに点灯順序を設定した状態を示す図である。
【符号の説明】
１ 二値化用パターン作成装置
１０ 基本パターン形状作成部
１１ 角度指定部
１２ ピクセル数指定部
１３ 演算部
２０ 点灯順序決定部
３０ 矩形状パターン作成部
５０ ＣＰＵ
５１ ディスプレイ
５２ ディスプレイコントローラ
５３ ＲＡＭ
５４ ＲＯＭ
５５ 記憶装置
５６ バス
５７ Ｉ／Ｏコントローラ
５８ キーボード
５９ マウス
６０ プリンタ
１００ コンピュータシステム[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a binarization pattern (dither pattern table) used for binarization processing for converting a multi-valued image (Continuous Tone Image) such as a natural image, a graphic image, or a color character into a binary image.)ofHow to makeAnd as much as printing equipmentAndSecondThe present invention relates to a pattern creation program for valuation.
[0002]
[Prior art]
When outputting a multi-value image such as a natural image, graphic image, or color character obtained from an input device such as a scanner from an output device such as a printer, the multi-value image is used as a color material. In order to express by ON / OFF (ink, toner, etc .; hereinafter, sometimes referred to as dots), it is necessary to perform binarization processing.
[0003]
A dither method is known as one of the binarization methods. In the dither method, the gradation density of a pixel is determined by comparing the value of a specific pixel (target pixel) in a multi-valued image with a preset threshold value, and a binarization pattern prepared in advance is used. This is a method for determining ON / OFF of the dot for the pixel according to the gradation density of the pixel.
[0004]
Conventionally, the creation of a binarization pattern is basically performed based on the intuition and experience of an expert. For example, when creating a binarization pattern, an aggregate for forming one halftone dot (hereinafter referred to as a basic pattern) is created, and error rounding processing is inserted at regular intervals to reduce the error. Or by developing the basic pattern into a huge pattern called a supercell, the shift of halftone dots is reduced.
[0005]
As methods for assisting an operator in creating such a binarization pattern, the methods disclosed in JP-A-10-126618, JP-A-7-146945, and JP-A-10-75361 are known. It has been.
Japanese Patent Application Laid-Open No. 10-126618 discloses a halftone dot pattern creation method in which when the halftone dot angle is other than 0 °, an error in the number of cells when a basic small cell is rotated changes the number of dots. A method of correcting by making it be disclosed is disclosed.
[0006]
Japanese Patent Laid-Open No. 7-146945 discloses a method for generating a dither pattern having an arbitrary halftone angle by obtaining a supercell by obtaining a side length and a halftone period using a floating point. Is disclosed.
Furthermore, Japanese Laid-Open Patent Publication No. 10-75361 discloses a technique for realizing a halftone dot close to a designated halftone angle using a supercell, and by treating a plurality of basic patterns as one unit. A technique for reducing the difference in the number of pixels included in a basic pattern forming one halftone dot is also disclosed.
[0007]
[Problems to be solved by the invention]
As described above, in the conventional binarization pattern creation method based on the intuition and experience of an expert, during the creation of the binarization pattern, the result of binarization processing using the binarization pattern is predicted. Is impossible. Therefore, the operator must repeat the process of creating the binarization pattern → printing → confirming, and select and use the optimum binarization pattern based on the results of these trial and error. There is a problem that it takes a very long time to create a pattern for value conversion.
[0008]
Further, there is no guarantee that the binarization pattern finally selected using the above-described method is the best one, and there are many operations performed manually by the operator, so that errors and misidentifications occur. There is also a problem that the probability is high. Moreover, since it is necessary to repeat trial and error, there is a problem that resources such as paper and ink used for that purpose are enormous and uneconomical.
[0009]
Further, in the halftone dot pattern generation method disclosed in Japanese Patent Laid-Open No. 10-126618, the number of cells is changed, so the number of pixels allocated to one halftone dot is not uniform. . As a result, there are problems that unevenness occurs in the image and moire occurs at the joint of the supercell.
Further, in the technique disclosed in Japanese Patent Laid-Open No. 7-146945, the side length and halftone period are obtained using a floating point, so that there is a problem that the final quantization error of processing becomes enormous. is there.
[0010]
Furthermore, in the method disclosed in Japanese Patent Laid-Open No. 10-75361, a super cell is created using a plurality of basic patterns to reduce errors, so that it is necessary to create a very large super cell. As a result, a large amount of memory area is required to read the halftone dot pattern, which raises the problem of an increase in hardware manufacturing costs.
[0011]
By the way, the diffusion type dither method is suitable for printing with a relatively low resolution. In general, when the amount of color material per pixel (for example, the amount of ink) to be fixed on a print medium is very small, the color material existing independently of other color materials is difficult to fix on the print medium. . Therefore, in the diffusion type dither method, when the resolution of the printer is improved as in recent years and the amount of the color material per pixel becomes small, there is a problem that the color material is difficult to be fixed on the print medium.
[0012]
In the dither method, as the gradation density of a pixel increases, a color material is placed (lighted) in order from a pixel close to this center around a specific point, thereby adjusting the gradation of the pixel. Centralized dither to express is known.
Since this concentrated dither has a small dot gain and the color material is stably fixed on the print medium, this concentrated dither method is more effective than the diffused dither method when the amount of the color material placed on each pixel is very small. It is desirable to use Therefore, a method for easily creating a binarization pattern for centralized dither is desired.
[0013]
  The present invention was devised in view of such problems, and can easily create a binarization pattern having a desired angle and the number of pixels, and particularly easily create a concentrated binarization pattern. And a binarization pattern creation method for realizing the method, and a method for the binarization pattern creation method capable of easily creating a minimum binarization pattern The binarization pattern created byThe printing device usedThe purpose is to provide.
[0014]
[Means for Solving the Problems]
  For this reason, the binarization pattern creation method according to the present invention (claim 1) includes a basic pattern shape creation step of creating a basic pattern shape of a binarization pattern by calculation, and lighting of pixels constituting the basic pattern. A lighting order determination step for determining the order and a rectangular pattern creation step for creating a rectangular pattern that functions as a binarization pattern based on the basic patternIn the basic pattern shape creation step, an angle specifying step for specifying the angle of the binarization pattern, a pixel number specifying step for specifying the number of pixels constituting the basic pattern, and an angle and pixel number specifying in the angle specifying step And a calculation step for creating a basic pattern shape by calculation based on the number of pixels specified in the step, and the shape of the basic pattern is an arbitrary parameter that satisfies the condition of the number of pixels n = ad + bc specified in the pixel number specification step Point A (c, 1), point B (a + c, b + 1), point C (0, d + 1), point specified by a, b, c, d (where a, b, c, d are integers) D (a, b + d + 1) is created as a quadrangle consisting of four points, and the angle of the created quadrangle is the angle designation step. It is selected to have an angle close to the angle of the binarization pattern specified in flops as basic patternIt is characterized by that.
[0015]
  In addition,In the rectangular pattern creating step, the rectangular pattern is sized (x) in the sub-scanning direction X of the rectangular pattern.
size (X) = max ((N ÷ gcd (B, n), (n ÷ gcd (D, n))
The size size (Y) of the rectangular pattern in the main scanning direction Y is
size (Y) = max ((N ÷ gcd (A, n), (n ÷ gcd (C, n))
So that(Claim 2).
[0016]
  Further, the printing apparatus of the present invention (Claim 3) includes a binarization processing unit that binarizes a multi-value image based on a binarization pattern, and the binarization performed by the binarization processing unit. A printing apparatus including an image forming unit that forms an image on a medium based on a binarization result, wherein a binarization pattern is created based on a basic pattern and corresponds to the gradation of a multi-value pixel Then, among the pixels constituting the basic pattern, in order from the pixel closest to the specific point of the basic pattern, and so that the length of the boundary contour line between the lit pixel and the non-lit pixel is minimized,The distance from the specific point of the basic pattern to each pixel constituting this basic pattern alternately for each pixel in the upper half and the lower half of this basic pattern, which is divided into two parts vertically from the horizontal line including the specific point. Is a weighting factor W (W = p−q × cos α−r × cos β; where α and β indicate the coordinates of the pixels forming this basic pattern shape by (x, y) and the coordinates of a specific point. This weight when represented by (PXDOT, PYDOT) is represented by α = x−PXDOT, β = y−PYDOT, and p, q, and r are non-negative real numbers, respectively. Starting from the pixel with the largest coefficient WIt is characterized in that a continuous halftone dot is generated by lighting.
[0017]
  Furthermore, the printing apparatus according to the present invention (claim 4) includes a binarization processing unit that binarizes a multi-valued image based on the binarization pattern, and the binarization performed by the binarization processing unit. A printing apparatus including an image forming unit that forms an image on a medium based on a binarization result, wherein a binarization pattern is created based on a basic pattern A pattern,According to the gradation of the multi-valued pixel, among the pixels constituting the basic pattern, the boundary contour line length between the lit pixel and the non-lit pixel is minimized in order from the pixel closest to the specific point of the basic pattern. In this way, each pixel constituting this basic pattern from specific points of the basic pattern alternately with respect to each pixel of the upper half and lower half of the basic pattern obtained by dividing the basic pattern into two parts up and down on the horizontal line including the specific point Is a weighting factor W (W = p−q × cos α−r × cos β; where α and β indicate the coordinates of the pixels forming this basic pattern shape by (x, y) and a specific point. Is expressed as (PXDOT, PYDOT), α = x−PXDOT, β = y−PYDOT, and p, q, and r are non-negative real numbers, respectively. Therefore, in the case of the representation, the basic pattern configured to light up in order from the pixel having the largest weighting factor W is selected from the continuous patterns repeatedly arranged in the main scanning direction Y and the sub-scanning direction X of the multivalued image. The size size (x) in the sub-scanning direction X is size (X) = max ((N ÷ gcd (B, n), (n ÷ gcd (D, n)), and the size size (Y) in the main scanning direction Y is size (Y) = max ((N ÷ gcd (A, n), (n ÷ gcd (C, n)) is a partial pattern generated by cutting out a rectangular pattern and extracting from this rectangular pattern a rectangular area having at least one lighting sequence in the basic pattern.It is characterized by that.
[0018]
  Also, the binarization pattern creation program of the present invention (Claim 5) provides a binarization pattern creation for causing a computer to execute a binarization pattern creation function used for binarization of a multi-value image. A basic pattern shape creation unit that creates a basic pattern shape of a binarization pattern by calculation, a lighting order determination unit that determines the lighting order of pixels constituting the basic pattern by calculation, and a basic pattern Based on this, let the computer function as a rectangular pattern creation unit that creates a rectangular pattern that functions as a binarization pattern by calculation.When the computer functions as the basic pattern shape creation unit, the angle specification unit that specifies the angle of the binarization pattern, the pixel number specification unit that specifies the number of pixels constituting the basic pattern, and the angle specification unit specify Based on the measured angle and the number of pixels specified by the pixel number specification unit, the computer functions as a calculation unit that generates a basic pattern shape by calculation, and the shape of the basic pattern is specified by the pixel number specification unit. Point A (c, 1), point B (a + c, b + 1) specified by arbitrary parameters a, b, c, d satisfying the condition of the number n = ad + bc (where a, b, c, d are integers) ), Point C (0, d + 1), and point D (a, b + d + 1) as a quadrangle, and the angle of the created quadrangle is an angle designation unit. Accordingly, as selected to have an angle close to the angle of the specified binary-coding pattern as the basic pattern, cause the computer to functionIt is characterized by that.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
(A) Description of embodiment
1 and 2 show a binarization pattern creation apparatus using a binarization pattern creation method as one embodiment of the present invention. FIG. 1 is a functional block diagram thereof, and FIG. 2 is a hardware diagram thereof. FIG. 1 is a diagram illustrating a configuration, and a binarization pattern creating apparatus 1 according to the present embodiment generates a centralized binarization pattern used for binarization of a multilevel image in a printer or a high-resolution printing apparatus, for example. To create.
[0020]
For example, in a computer system 100 as shown in FIG. 2, the computer system 100 functions as the binarization pattern creation device 1 by executing a binarization pattern creation program stored in the ROM 54 or the storage device 55. It is supposed to be.
As shown in FIG. 2, the computer system 100 includes a CPU 50, a display 51, a display controller 52, a RAM 53, a ROM 54, a storage device 55, a bus 56, an I / O controller 57, a keyboard 58, a mouse 59, and a printer 60. Has been.
[0021]
The CPU 50 performs various calculations and controls in the computer system 100, and executes various programs stored in the ROM 54 and the storage device 55.
The RAM 53 is used for temporarily expanding and storing data when the CPU 50 performs an operation. The ROM 54 and the storage device 55 store various programs and data. The display controller 52 controls display on the display 51, and the display 51 displays various information according to the control of the display controller 52.
[0022]
The I / O controller 57 controls various input / output devices such as a printer 60, a keyboard 58, and a mouse 59. A keyboard 58 and a mouse 59 are used by the user to perform various inputs. The printer 60 performs printing by fixing a color material such as ink or toner on a print medium such as paper.
In the computer system 100, the CPU 50 executes a binarization pattern creation program stored in the ROM 54 or the storage device 55, so that a basic pattern shape creation unit 10, a lighting sequence determination unit 20, and a rectangular shape, which will be described later, are formed. The function as the pattern creation unit 30 is realized, and the computer system 100 functions as the binarization pattern creation apparatus 1.
[0023]
As shown in FIG. 1, the binarization pattern creation apparatus 1 includes a basic pattern shape creation unit 10, a lighting order determination unit 20, and a rectangular pattern creation unit 30.
FIG. 3 is a conceptual diagram of a general multilevel image binarization process. As shown in FIG. 3, in the binarization process, a threshold value in which the pixel value of the multilevel image is set in advance by a comparator. Binarization is performed in comparison with.
[0024]
The binarization pattern controls a threshold value in binarization, and is configured by repeatedly arranging basic patterns having a specific shape in the main scanning direction and the sub-scanning direction. FIG. 4 is a diagram showing an example of the shape of the basic pattern. The basic pattern shape creation unit 10 creates the shape of the basic pattern of the binarization pattern as shown in FIG. 4, and as shown in FIG. 1, the angle designation unit 11, the pixel number designation unit 12, and the calculation A portion 13 is provided.
[0025]
The angle designation unit 11 designates the angle of the binarization pattern. In practice, the user designates this angle (for example, 30 degrees, 45 degrees, etc.) in advance as necessary. Yes.
The pixel number designating unit 12 designates the number of pixels (n: natural number) constituting the basic pattern. Thereby, the number of gradations and the resolution expressed by one halftone dot are specified. Actually, the user specifies the number of pixels (n) in advance.
[0026]
The computing unit 13 creates a basic pattern shape by computation based on the angle designated by the angle designation unit 11 and the number of pixels designated by the pixel number designation unit.
The calculation unit 13 is a combination of arbitrary parameters a, b, c, and d (where a, b, c, and d are integers) satisfying the condition of the pixel number n = ad + bc specified by the pixel number specifying unit 12. Based on this, a rectangular ABCD (see FIG. 5A) is formed, and the shape of the rectangular ABCD is used as the shape of the basic pattern.
[0027]
At this time, the line segments AB, AC, CD, and BD constituting the quadrangle ABCD can be expressed as follows.
Line segment AB: ay = b (x−c) + a
Line segment AC: cy = −d (x−c) + c
Line segment CD: ay = bx + a (d + 1)
Line segment BD: cy = −d (x−a) + (b + d + 1) c
The calculation unit 13 creates a basic pattern with pixels included in the quadrangle ABCD. At this time, for the pixels located on the line segments AB, BC, CD, DA, the following (1) to (▲) It is handled according to the law of 5 ▼.
[0028]
When an integer lattice point of the coordinate system x, y is a coordinate point (see FIG. 5A),
(1) Point A is included.
(2) All points on line segments AB and AC are included.
(3) When the y-coordinate value of the point B is smaller than the y-coordinate value of the point C, the points on the line segment CD are included.
(4) When the y coordinate value of the point B is larger than the y coordinate value of the point C, the points on the line segment BD are included.
(5) Do not include points B, C, and D.
[0029]
By forming the shape of the basic pattern according to the above rules (1) to (5), the continuity of halftone dots is maintained when the formed basic pattern is repeatedly arranged in the main scanning direction and the sub-scanning direction. The
FIGS. 5A and 5B are diagrams showing an example of a quadrilateral ABCD, FIG. 5A is a diagram showing the shape of the quadrilateral ABCD by coordinate values, and FIG. 5B is a diagram showing the quadrilateral ABCD by pixels. It is. The examples shown in FIGS. 5A and 5B show the case where the parameters (a, b, c, d) = (6, 6, 7, 5).
[0030]
As shown in FIG. 5 (a), the rectangular ABCD formed by A (7,1), B (13,7), C (0,6) and D (6,12) is the above-mentioned (1) to When the rule (5) is applied, a basic pattern constituted by the arrangement of pixels as shown in FIG. 5B is formed.
That is, the basic pattern shape creation unit 10 calculates the coordinates of point A, point B, point C, and point D constituting the quadrangle ABCD based on the parameters a, b, c, and d calculated as described above, The basic pattern shape is specified.
[0031]
In order to create a pattern for binarization without unevenness, straight lines formed by connecting two adjacent points among the four points A, B, C, and D in the basic pattern region, and those It is necessary that a straight line formed by connecting points other than these two points be parallel. Therefore, the rectangle ABCD needs to be a parallelogram. As described above, the coordinate values of the four points A, B, C, D satisfying this condition are A (c, 1), B (a + c, b + 1), C (0, d + 1), D (a, b + d + 1). Is represented by
[0032]
  That is, the shape of the basic pattern is specified by arbitrary parameters a, b, c, d satisfying the condition of the pixel number n = ad + bc specified by the pixel number specifying unit 12, and points A (c, 1), B (A + c, b + 1),pointC (0, d + 1),pointIt is created as a quadrangle consisting of four points D (a, b + d + 1).
[0033]
Further, since these parameters a, b, c, d can be combined with various values, a plurality of types of quadrangle ABCD are formed according to these various parameters a, b, c, d.
In the present embodiment, an angle (an angle of the quadrilateral ABCD) of the line segments AB, CD, AC, and BD constituting the quadrilateral ABCD among these plural types of quadrilateral ABCD is designated by the angle designation unit 11. In addition, a pattern closest to the angle of the binarization pattern is selected as a basic pattern, and parameters a, b, c, and d constituting the quadrangle ABCD are stored.
[0034]
That is, the basic pattern shape creation unit 10 changes the shape of the basic pattern to any parameters a, b, c, d (provided that the number of pixels n = ad + bc specified by the pixel number specifying unit 12 satisfies the condition). , C, and d are integers) and are created as a quadrangle consisting of four points, point A (c, 1), point B (a + c, b + 1), C (0, d + 1), and D (a, b + d + 1). Among the created quadrangles, those having an angle close to the angle of the binarization pattern designated by the angle designation unit 11 are selected as basic patterns.
[0035]
Here, a basic pattern shape creation method by the calculation unit 13 will be described with reference to a flowchart (step A10 to step A110) shown in FIG.
The calculation unit 13 acquires the dot angle and the pixel number (n) specified by the angle specifying unit 11 and the pixel number specifying unit 12 (step A10), and is smaller than the pixel number n (or within a predetermined range). The two integers a and b are arbitrarily selected (step A20). And the calculating part 13 calculates all the integers c and d in which n = ad + bc is materialized about these integers a and b (or all within the predetermined range) (step A30).
[0036]
Next, the calculation unit 13 calculates A (c, 1), B (a + c, b + 1), C (0, d + 1), and D (a, b + d + 1) based on the obtained parameters a, b, c, and d. A quadrangle formed by four points is designated as a basic pattern area (step A40).
Next, the arithmetic unit 13 counts the number of pixels included in the rectangle ABCD (step A50).
[0037]
The calculation unit 13 determines whether or not the number (N) of pixels included in the rectangle ABCD matches the number of pixels (n) acquired in Step A10 (Step A60). In order to select another combination of a, b, c, and d (step A70), the process returns to step A20.
[0038]
On the other hand, when the number (N) of pixels included in the rectangle ABCD matches the number (n) of pixels acquired in step A10 (see YES route in step A60), the calculation unit 3 then The angle of the rectangle ABCD, that is, the angle of the halftone dot is calculated (step A80).
Specifically, the calculation unit 3 calculates an angle formed between the line segment AB (line segment BD) and the line segment CD (line segment AC) constituting the quadrangle ABCD, respectively, with respect to the x axis (FIG. 5). Further, the average value of these angles is calculated as the halftone dot angle.
[0039]
Then, the calculation unit 13 determines whether or not there is a combination of other parameters a, b, c, and d (step A90). If another parameter exists (see YES route in step A90). ), And returns to Step A20. If there is no other combination of parameters (see NO route in step A90), the angle of each quadrilateral ABCD formed by each parameter for all the obtained parameters is the dot dot specified in step A10. The parameters a, b, c, and d composing the angle of the halftone dot closest to the designated angle are selected by comparing with the angle (step A100).
[0040]
FIG. 7 is a diagram showing an example in which a square halftone dot angle determined by parameters a, b, c, and d is compared with a predesignated angle. The example shown in FIG. 7 shows a case where the angle of the halftone dot specified in advance is 45 degrees and the number of pixels of the basic pattern designated in advance is 72, and the angle of dot halftone (unit: radian) ) Are arranged in the top 10 with less error (slope).
[0041]
As shown in FIG. 7, the calculation unit 13 performs comparison and examination for each parameter, and selects the parameters a, b, c, and d that constitute the halftone dot angle closest to the specified angle. It has become.
Then, the calculation unit 13 outputs the selected parameters a, b, c, and d to a file and stores them in the storage device 55 or the like (step A110).
[0042]
In the binarization pattern, the order (hereinafter referred to as the lighting order) for fixing the color material (ink, toner, etc.) is set for each pixel constituting the basic pattern according to the gradation of the pixel. FIG. 8 is a diagram illustrating an example of the lighting order of pixels. The lighting order determination unit 20 determines the lighting order of the pixels constituting the basic pattern as shown in FIG. 8, and the pixels and specific points in the basic pattern (for example, the center of gravity or the center of the basic pattern) The lighting order of each pixel is determined based on the distance.
[0043]
Further, when setting the lighting order, the lighting order determination unit 20 sets the lighting order in order from the pixel closest to the specific point of the basic pattern, and the length of the boundary contour between the lighting pixel and the non-lighting pixel is minimized. Has been determined.
FIG. 9 and FIG. 10 are diagrams showing extracted pixels in which the lighting order is set, and FIG. 9 sets the lighting order so that the length of the boundary contour line between the lit pixel and the non-lit pixel is minimized. FIG. 10 is a diagram showing an example in which the lighting order is not set so that the length of the boundary contour line between the lit pixel and the non-lit pixel is minimized.
[0044]
As shown in FIG. 9, the lighting order determination unit 20 sets the lighting order in order from the pixel closest to the specific point of the basic pattern, and the length of the boundary contour between the lighting pixel and the non-lighting pixel is minimized. By determining the dot gain, the dot gain can be reduced as compared with the case where the lighting order is determined as shown in FIG.
Specifically, the lighting order determination unit 20 represents a distance from a specific point in the basic pattern to each pixel constituting the basic pattern by a weighting factor W using the following equation (1), and the weight W The lighting order is set in order from the largest pixel.
[0045]
W = p−q × cos α−r × cos β (1)
Here, α and β indicate the coordinates of the pixel forming the basic pattern shape by (x, y), and the coordinates of the point (specific point) serving as the center or the center of gravity of the basic pattern shape by (PXDOT, PYDOT). In this case, α = x−PXDOT and β = y−PYDOT.
[0046]
In addition, p, q, and r are values (coefficients) set as appropriate, and are real numbers that are not negative numbers. q and r are coefficients for defining the shape of the halftone dot to be formed. When q becomes large, the halftone dot formed has an elliptical shape that is long in the x direction, and is formed when r becomes large. The halftone dot has an elliptical shape that is long in the y direction. When q = r, the halftone dot has a circular shape. p is a number that is set as appropriate so that the calculation result of Expression (1) does not become negative, and is for facilitating handling (for example, sorting) of the calculated weight (W).
[0047]
Thus, the lighting order determination unit 20 determines the lighting order based on the weight (W) set by calculation for each pixel according to the distance between the pixel and the specific point in the basic pattern. ing.
Hereinafter, the lighting order determination method by the lighting order determination unit 20 will be described according to the flowchart (steps B10 to B80) illustrated in FIG. 11 with reference to FIG.
[0048]
FIGS. 12A to 12C are diagrams for explaining a method for determining the lighting order. FIG. 12A shows a state in which the lighting order is set halfway, and FIG. The figure which shows the state which rotated the basic pattern-(theta), FIG.12 (c) is a figure which shows the state which set the lighting order to the basic pattern. 12A to 12C show an example in which the lighting order is set for a basic pattern in which the angle of halftone dots is 45 degrees and the number of pixels constituting the basic pattern is 72.
[0049]
The lighting order setting unit 20 first acquires the used halftone dot angle, halftone dot distance, p, q, and r coefficients for the basic pattern shape created by the basic pattern shape creation unit 10. A point that becomes the center or the center of gravity of the basic pattern shape is determined as a specific point (PXDOT, PYDOT) (step B10).
The specific points (PXDOT, PYDOT) of the basic pattern may be designated in advance by the operator, or may be calculated by the lighting order determination unit 20.
[0050]
When the specific point is determined, if the specific point is located at the center of the pixel (see FIGS. 12A to 12C), the coordinates of the specific point are indicated by natural numbers, and the specific point is adjacent to the specific point. When it is located on the boundary line between the matching pixels, it is shown as a natural number ± 0.5. For example, in the basic pattern shown in FIG. 12A, when the center point C is a specific point, the coordinates of the specific point can be indicated as (5.5, 5.5).
[0051]
In addition, the lighting order determination unit 20 calculates the distance between specific points when the basic patterns are arranged next to each other. In the example shown in FIG. 12A, the distance between the center points is 8.248582814.
Next, the lighting order determination unit 20 acquires the basic pattern created by the basic pattern shape creation unit 10 (step B20), and for each pixel, the sub-scanning direction (x-axis direction) and the main scanning direction from a specific point. Each distance in the y-axis direction is obtained. Then, the lighting order determination unit 20 stores the positions of the respective pixels before the rotation, and uses the affine transformation to convert the basic pattern to −θ around the center point as shown in FIG. (Θ is an angle of a halftone dot set in advance; for example, 45 degrees), and is returned to a substantially rectangular shape (step B30).
[0052]
Then, the lighting order determination unit 20 calculates the weight (W) for each pixel of the basic pattern rotated by −θ using the above-described equation (1) (step B40).
Thereafter, the lighting order determination unit 20 sets the lighting order based on the weight (W) (step B50).
[0053]
The lighting order determination unit 20 divides the basic pattern rotated by −θ into two parts vertically from the horizontal line including the center point (specific point). First, each pixel in the upper half of the basic pattern ((pixel of the basic pattern) The number (2 + 1) pixels) is sequentially searched for the weight (W) from the upper left pixel in the horizontal right direction. Then, the search for the weight (W) for each pixel in the horizontal direction is repeated while moving one line in the vertical downward direction until the pixel at the lower right of the basic pattern is reached. Thereafter, the lighting order determination unit 20 sets the lighting order “1” to the pixel having the largest weight (W) among all the pixels constituting the upper half of the basic pattern.
[0054]
Next, the lighting order determination unit 20 weights the lower half pixels of the basic pattern ((number of pixels of the basic pattern ÷ 2 + 1) pixels) from the lower right pixel in the horizontal left direction (W). The search is sequentially performed. Then, the search for the weight (W) for each pixel in the horizontal direction is repeated while moving one line in the vertical direction until reaching the upper left pixel of the basic pattern. Thereafter, the lighting order determination unit 20 sets the lighting order “2” to the pixel having the largest weight (W) among all the pixels constituting the lower half of the basic pattern.
[0055]
In the following, the lighting order determining unit 20 excludes the pixels whose lighting order has already been determined, and alternately turns on the pixels in the upper half and the lower half of the basic pattern in order of increasing weight (W). Set.
When the lighting order is set, if two or more pixels have the same weight (W) value, the lighting order determination unit 20 sets the lighting order first from the pixel accessed earlier. It has become.
[0056]
Next, as shown in FIG. 12C, the lighting order setting unit 20 associates the lighting order set in the basic pattern rotated by −θ with the basic pattern (basic pattern before rotating by −θ). (Step B60), the lighting order is set for the basic pattern (step B70).
Then, the lighting order determination unit 20 determines whether or not the lighting order has been set for all the pixels in the basic pattern (step B80), and if there is a pixel for which the lighting order has not been set (step B80). NO route reference), and the process returns to step B40. If the lighting order is set for all pixels (see YES route in step B80), the process is terminated.
[0057]
Further, the lighting order setting unit 20 determines the lighting order of pixels based on the distance between the pixel and a specific point in the basic pattern and a constant coefficient (flatness factor) related to the distance. The lighting order may be determined.
Specifically, the lighting order determination unit 20 is based on a distance from a specific point in the basic pattern to each pixel constituting the basic pattern, and a certain coefficient (flatness (E)) related to the distance. Then, the weight (W) of each pixel may be calculated using the following equation (2), and the lighting order may be set in order from the pixel having the largest weight W.
[0058]
W = p−E × cos α− (p−E) × cos β (2)
Here, α and β indicate the coordinates of the pixel forming the basic pattern shape by (x, y), and the coordinates of the point (specific point) serving as the center or the center of gravity of the basic pattern shape by (PXDOT, PYDOT). In this case, α = x−PXDOT and β = y−PYDOT.
[0059]
P and E are values (coefficients) set as appropriate. E is a coefficient (flatness) for defining the shape of halftone dots to be formed, and is a floating point number that satisfies the condition of 0.0 <E ≦ p. When p = 2.0 and E = 1.0, the halftone dots are circular, and as the flatness ratio (E) approaches 0.0 or 2.0, the halftone dots are elongated. Become. p is a number set as appropriate so that the calculation result of Expression (2) does not become negative, and is for facilitating handling of the calculated weight (W) (for example, sorting).
[0060]
Hereinafter, another method for determining the lighting order by the lighting order determination unit 20 will be described with reference to the flowchart shown in FIG. 13 (steps C10 to C80).
First, the lighting order setting unit 20 acquires the used halftone dot angle, halftone dot distance, p, q, and r coefficients for the basic pattern shape created by the basic pattern shape creation unit 10, and A point that becomes the center or the center of gravity of the basic pattern shape is determined as a specific point (PXDOT, PYDOT) (step C10).
[0061]
The specific points (PXDOT, PYDOT) of the basic pattern may be designated in advance by the operator, or may be calculated by the lighting order determination unit 20.
Next, the lighting order determination unit 20 acquires the basic pattern created by the basic pattern shape creation unit 10 (step C20), stores the position of each pixel before the rotation, and performs affine transformation on the basic pattern. Then, it is rotated by -θ (θ is a preset dot angle; for example, 45 degrees) around the center point to return to a substantially rectangular shape (step C30).
[0062]
Then, the lighting order determination unit 20 calculates the weight (W) in consideration of the flatness rate for each pixel of the basic pattern rotated by −θ using the above-described equation (2) (step C40).
Thereafter, the lighting order determination unit 20 sets the lighting order based on the weight (W) (step C50).
[0063]
The lighting order determination unit 20 divides the basic pattern rotated by −θ into two parts vertically from the horizontal line including the center point (specific point). First, each pixel in the upper half of the basic pattern ((pixel of the basic pattern) The number (2 + 1) pixels) is sequentially searched for the weight (W) from the upper left pixel in the horizontal right direction. Then, the search for the weight (W) for each pixel in the horizontal direction is repeated while moving one line in the vertical downward direction until the pixel at the lower right of the basic pattern is reached. Thereafter, the lighting order determination unit 20 sets the lighting order “1” to the pixel having the largest weight (W) among all the pixels constituting the upper half of the basic pattern.
[0064]
Next, the lighting order determination unit 20 weights the lower half pixels of the basic pattern ((number of pixels of the basic pattern ÷ 2 + 1) pixels) from the lower right pixel in the horizontal left direction (W). The search is sequentially performed. Then, the search for the weight (W) for each pixel in the horizontal direction is repeated while moving one line in the vertical direction until reaching the upper left pixel of the basic pattern. Then, the lighting order determination unit 20 sets the lighting order “2” to the pixel having the largest weight (W) among all the pixels constituting the lower half of the basic pattern.
[0065]
In the following, the lighting order determining unit 20 excludes the pixels whose lighting order has already been determined, and alternately turns on the pixels in the upper half and the lower half of the basic pattern in order of increasing weight (W). Set.
When the lighting order is set, if two or more pixels have the same weight (W) value, the lighting order determination unit 20 sets the lighting order first from the pixel accessed earlier. It has become.
[0066]
Next, the lighting order setting unit 20 lights the basic pattern by associating the basic pattern (basic pattern before being rotated by -θ) with the lighting order set for the basic pattern rotated by -θ (step C60). The order is set (step C70).
Then, the lighting order determination unit 20 determines whether or not the lighting order has been set for all the pixels in the basic pattern (step C80), and if there is a pixel for which the lighting order has not been set (step C80). NO route), and return to Step C40. If the lighting order is set for all pixels (see YES route in step C80), the process is terminated.
[0067]
The rectangular pattern creating unit 30 creates a rectangular pattern that functions as a binarization pattern based on the basic pattern, and repeatedly arranges the basic patterns described above in the main scanning direction and the sub-scanning direction of the image. A rectangular pattern having a specific size is cut out from the continuous pattern formed in this way as a binarization pattern.
[0068]
In general, when binarizing a multi-value image, when the CPU 50 develops a binarization pattern on the RAM 53, the binarization pattern shaped into a square or a rectangular rectangle is developed on the RAM 53. is there.
FIG. 14 is a diagram showing an example of a rectangular pattern, and the rectangular pattern creation unit 30 cuts out and creates a rectangular pattern of a specific size as shown in FIG. 14 as a binarization pattern. Yes.
[0069]
That is, the rectangular pattern creation unit 30 has a halftone dot of the same shape when a binarization pattern (hereinafter also referred to as a rectangular pattern) formed in a rectangular shape is repeatedly arranged in the main scanning direction and the sub-scanning direction of the image. A rectangular pattern having a specific size is formed so that the dots are continuously arranged at the same angle and at equal intervals.
Specifically, the rectangular pattern creating unit 30 calculates the size of the rectangular pattern in the sub-scanning direction (size (X); the unit is the number of pixels) by the following formula (3), and the following formula (4) ) To calculate the size (size (Y); the unit is the number of pixels) of the rectangular pattern in the main scanning direction.
[0070]
size (X) = max ((n ÷ gcd (b, n), (n ÷ gcd (d, n))) (3)
size (Y) = max ((n ÷ gcd (a, n), (n ÷ gcd (c, n))) (4)
Note that n is the number of pixels constituting the basic pattern and is designated by the pixel number designation unit 12. Further, a, b, c, and d are parameters calculated by the calculation unit 13. Further, in the formulas (3) and (4), gcd represents the greatest common divisor, for example, gcd (a, n) represents the greatest common divisor of a and n.
[0071]
Max (...,...) Indicates that the larger one of the numerical values in parentheses is selected. For example, max ((n ÷ gcd (b, n), (n ÷ gcd (d , N)) indicates that the larger one of (n ÷ gcd (b, n) and (n ÷ gcd (d, n)) is selected.
The rectangular pattern creation unit 30 repeatedly forms a basic pattern in the main scanning direction and the sub-scanning direction of the image to form a continuous pattern. From an arbitrary start point in this continuous pattern, size (X) and main By cutting out a rectangular portion of size (Y) in the scanning direction, a rectangular pattern of a specific size is cut out and created as a binarization pattern.
[0072]
A method for creating a rectangular pattern by the rectangular pattern creating unit 30 will be described with reference to a flowchart (steps D10 to D40) shown in FIG.
The rectangular pattern creation unit 30 repeatedly arranges the basic pattern assigned the lighting order by the lighting order determination unit 20 in the main scanning direction and the sub-scanning direction (step D10), and then the above equations (3) and (4) ) To calculate size (X) and size (Y) (step D20).
[0073]
Then, the rectangular pattern creating unit 30 determines an arbitrary starting point (step D30), and cuts out a rectangular portion of size (X) in the sub-scanning direction and size (Y) in the main scanning direction from this starting point. A rectangular pattern is created (step D40).
For example, when the parameters (a, b, c, d) = (6, 6, 7, 5) for forming the basic pattern, the sub-scanning direction size size (X) and the sub-scanning direction size size ( Y) is obtained as follows from the above-described equations (3) and (4).
[0074]
Size (X) = max (((72 ÷ gcd (6,72)), (72 ÷ gcd (5,72))) = 72
Size (Y) = max (((72 ÷ gcd (6,72)), (72 ÷ gcd (7,72))) = 72
That is, after determining an arbitrary starting point, the rectangular pattern forming unit 30 has a rectangular portion composed of 5184 pixels from the starting point to 72 pixels in the sub-scanning direction and 72 pixels in the main scanning direction. Are extracted into a rectangular pattern.
[0075]
Here, it is possible to fill the plane by repeatedly arranging the rectangular patterns specified by the equations (3) and (4) in the main scanning direction and the sub-scanning direction, as shown in FIG. , (B). FIG. 16A is a diagram for explaining a basic pattern used for proving a rectangular pattern, and FIG. 16B is a diagram showing an example in which the basic pattern is developed on a plane.
[0076]
A basic pattern as shown in FIG. 16A is defined with four parameters for determining the boundary of the basic pattern as a, b, c, d, and n as the number of dots included in the basic pattern.
In addition, in FIG. 16A, the processing of the grid points on the boundary line includes that the points on the lower side and the left side are included in the basic pattern, and the points on the upper side and the right side are not included in the basic pattern. To do. In the example shown in FIG. 16B, a = 5, b = 2, c = 2, d = 4, and n = 24.
[0077]
Here, the x and y coordinates of the lattice point indicated by (i, j) are expressed by the following equations. x coordinate: ia-jc
y coordinate: ib + jd
Therefore, in order to cover the entire plane with a rectangular pattern, the minimum value of (ia−jc) when y coordinate (ib + jd) = 0 and the value when x coordinate (ia−jc) = 0 ( It is necessary to obtain the minimum value of ib + jd).
therefore,
[0078]
[Expression 1]

It becomes.
here,
[0079]
[Expression 2]

So,
[0080]
[Equation 3]

Then,
[0081]
[Expression 4]

It becomes.
[0082]
However, since i and j must both be integers, gcd (jd, b) = b and gcd (ib, d) = d must be satisfied.
Because ib-jd = 0,
i = -jd / b
i is an integer,
jd> b and jd divided by b is 0
Therefore, the greatest common divisor between jd and b must be b.
[0083]
Similarly, from ib + jd = 0
j = -ib / d
j is an integer (regardless of positive / negative),
ib> d and the remainder obtained by dividing ib by d is 0.
Therefore, the greatest common divisor between ib and d is d.
Considering these things, n / b and n / d are both integers,
[0084]
[Equation 5]

The minimum value to be obtained is
[0085]
[Formula 6]

Given in.
Since the same applies to the y direction, it is a binarization pattern that realizes the same binarization as the basic pattern specified by the parameters (a, b, c, d), and has the smallest rectangular shape. The size (number of pixels) in the sub-scanning direction of the pattern is
[0086]
[Expression 7]

It becomes. Similarly, the size (number of pixels) of the smallest rectangular pattern in the main scanning direction is
[0087]
[Equation 8]

It becomes.
For example, in the basic pattern of parameters (a, b, c, d) = (5, 2, 2, 4), when the sub-scanning direction size = H and the main scanning direction size = V,
[0088]
[Equation 9]

It becomes.
In the (7, 2, 4, 8) pattern,
[0089]
[Expression 10]

It becomes.
Note that the rectangular pattern creation unit 30 has the characteristics of this rectangular pattern in a rectangular pattern formed by cutting out a rectangular pattern of a predetermined size calculated using the above-described equations (3) and (4). A partial pattern may be cut out from a rectangular pattern, and the rectangular pattern may be represented by this partial pattern.
[0090]
At this time, the rectangular pattern creating unit 30 cuts out a rectangular area composed of Y × i pixels having a size Y in the main scanning direction and a size i in the sub-scanning direction as a partial pattern.
Here, the main scanning direction size Y of the partial pattern is the main scanning direction size of the rectangular pattern given as a specific size, and the sub-scanning direction size i is the area of one basic pattern. The minimum necessary for including the pixels assigned with all kinds of lighting order values (numerical values indicating the lighting order determined for all the pixels constituting the basic pattern by the lighting order determination unit 20). In the sub-scanning direction (number of pixels).
[0091]
Here, a method in which the rectangular pattern creating unit 30 cuts out the partial pattern will be described with reference to a flowchart (steps E10 to E50) shown in FIG.
After inputting 1 to the value of the counter m (step E10), the rectangular pattern creation unit 30 starts to output pixels corresponding to m columns ((Y × m) pixels in the main scanning direction from the start point of the rectangular pattern. ) To cut out the rectangular area formed (step E20).
[0092]
Then, the rectangular pattern creating unit 30 determines whether or not at least one lighting order value (1 to n) in the basic pattern exists in each of the (Y × m) pixels. (Step E30) If it does not exist (see NO route in Step E30), m is incremented (Step E50), and the process returns to Step E20.
[0093]
If at least one lighting order value in the basic pattern is present in each of these (Y × m) pixels (see YES route in step E30), then this (Y × m It is determined whether or not there are i lighting order values in the basic pattern for each pixel in the basic pattern (step E40).
[0094]
Then, the rectangular pattern creation unit 30 determines that each of the lighting order values in the basic pattern does not exist i in the basic pattern in the (Y × m) pixels (NO in step E40). Step E50). Further, when there are i lighting order values in the basic pattern in i (Y × m) pixels in the basic pattern (see YES route in step E40), the process is terminated.
[0095]
The partial pattern thus formed is stored in the storage device 55 or the RAM 53, and when binarization is performed, the partial pattern is continuously used while shifting the reference position, thereby performing binarization processing. Can do.
FIG. 18 is a diagram illustrating an example of a partial pattern, and illustrates an example where Y = n = 17 and i = 1.
[0096]
For example, in the case of the partial pattern shown in FIG. 18 (3, 11, 6, 4,..., 2, 1 from the top), by referencing this partial pattern while shifting by 14 (for example, the next line is 7, 10, 2,..., 14, 8, 5) Binarization processing can be performed.
The example shown in FIG. 18 is for the case where Y = n. However, the present invention is not limited to this. Y may be a numerical value other than n, and does not depart from the spirit of the present invention. Various modifications can be made.
[0097]
With such a configuration, the binarization pattern creating apparatus 1 creates a binarization pattern using the binarization pattern creation method as one embodiment of the present invention. A binarization pattern creation method as one embodiment of the present invention will be described with reference to the flowchart (steps F10 to F30) shown in FIG.
First, the basic pattern shape creation unit 10 creates a basic pattern shape based on the designated halftone dot angle (θ) and the number of gradations (n) (step F10). Thereafter, the lighting order determination unit 20 determines the lighting order for each pixel based on the distance between each pixel constituting the basic pattern and a specific point (for example, the center of gravity or the center of the basic pattern) (step F20). . At this time, a flatness ratio may be set between each pixel and a specific point.
[0098]
Then, the rectangular pattern creating unit 30 has a rectangular shape of a predetermined size calculated from the continuous pattern in which the basic pattern is repeatedly arranged in the main scanning direction and the sub-scanning direction of the image using the above formulas (3) and (4). The pattern is cut out as a binarization pattern (step F30). It should be noted that a characteristic part may be cut out from the rectangular pattern thus formed.
[0099]
The printing apparatus forms an image on a medium (paper or the like) based on the binarization pattern formed as described above, and is realized by a printer such as an ink jet printer or a laser printer. .
In this printing apparatus, for example, an ink jet mechanism, a laser diode unit, a photosensitive drum, and the like function as an image forming unit that forms an image on a medium.
[0100]
Further, a processor or the like provided in the printing apparatus may function as a binarization processing unit that performs binarization based on the binarization pattern. In the printing system, the printing apparatus (printer) A connected computer may function as the binarization processing unit, and various modifications can be made without departing from the spirit of the present invention.
[0101]
In these printing apparatuses or printing systems, the binarization processing unit binarizes the multi-valued image based on the binarization pattern created as described above, thereby turning on the color material on the medium. / OFF is determined.
Then, an image is formed by the image forming unit placing a color material on the medium based on the result of the binarization process.
[0102]
As described above, according to the binarization pattern creating apparatus 1 as one embodiment of the present invention, the basic pattern shape creation, the lighting order setting, and the rectangular pattern formation process are automatically performed based on mathematical expressions. Therefore, a binarization pattern can be easily created. Therefore, even if the operator is not skilled in creating the binarization pattern, the dither pattern can be created easily in a short time.
[0103]
The basic pattern shape creation unit 10 designates the angle of the binarization pattern, designates the number of pixels constituting the basic pattern, and creates the basic pattern shape by calculation based on the designated angle and the number of pixels. Therefore, a basic pattern shape having a desired angle and the number of pixels can be easily created.
In addition, since the lighting order determination unit 20 determines the lighting order of the pixels based on the distance between the pixel and a specific point (center or center of gravity) in the basic pattern, a concentrated binarization pattern can be easily created. can do.
[0104]
Further, the lighting order determination unit 20 determines the lighting order of the pixels based on the distance between the pixel and a specific point in the basic pattern and a constant coefficient (flatness ratio) related to the distance, so that the network With the dot dot angle maintained, the dot pattern can be smoothly changed from a circular shape to an elliptical shape, and the pattern for binarization that makes dot misalignment and moire inconspicuous can be done with less man-hours. Can be created reliably.
[0105]
Furthermore, the lighting order determination unit 20 sets the lighting order in order from the pixel closest to the specific point of the basic pattern, so that even a printer with unstable color material fixing performance can reliably place colors.
Then, by determining the length of the boundary contour line between the lit pixel and the non-lit pixel to be the minimum, the dot gain is reduced, the color material is stably applied to the print medium, and the output quality is improved.
[0106]
Furthermore, the rectangular pattern creation unit 30 creates a rectangular pattern of a specific size as a binarization pattern from a continuous pattern formed by repeatedly arranging basic patterns in the main scanning direction and the sub-scanning direction of the image. By doing so, a rectangular binarization pattern can be easily created.
In addition, the rectangular pattern creating unit 30 cuts out a partial pattern having the characteristics of the rectangular pattern from the rectangular pattern, and represents the rectangular pattern by this partial pattern, so that the binarization pattern is used in the binarization process. The memory area (RAM 53, etc.) required for developing the data and the area for storing the binarization pattern (ROM 54, storage device 55, etc.) can be reduced, and the processing speed can be improved. The manufacturing cost of the wear can be reduced.
[0107]
Furthermore, the binarization pattern created by the binarization pattern creation method of the present invention is a partial pattern having the characteristics of a rectangular pattern, and this partial pattern has a size Y in the main scanning direction and sub-scanning. This is a rectangular area composed of Y × i pixels of the direction size i, the main scanning direction size Y is the main scanning direction size of the rectangular pattern given as a specific size, and the sub-scanning direction size i is , Each region is given all kinds of lighting order values (numerical values indicating the lighting order determined for all the pixels constituting the basic pattern in the lighting order determination step F20) included in one basic pattern. Since it is the minimum size (number of pixels) in the sub-scanning direction necessary for including pixels, the size of the binarization pattern can be reduced. It is possible to reduce the area for storage of a memory area and binarization pattern required for binarization, thereby improving the processing speed can reduce the manufacturing cost of the other hardware.
[0108]
  Further, the shape of the basic pattern is designated by an arbitrary parameter a, b, c, d (where a, b, c, d are integers) that satisfy the condition of the designated number of pixels n = ad + bc, point A (C, 1), point B (a + c, b + 1),pointC (0, d + 1),pointCreate as a quadrangle consisting of four points D (a, b + d + 1), and select the created quadrangle having an angle close to the angle of the specified binarization pattern as the basic pattern. Thus, the shape of the basic pattern can be easily created, and thereby the binarization pattern can be easily created.
[0109]
Furthermore, the lighting order can be easily set by determining the lighting order based on the weight set by calculation for each pixel according to the distance between the pixel and the specific point in the basic pattern. Also, the binarization pattern can be easily created.
In addition, the rectangular pattern has a size size (x) in the sub-scanning direction X of the rectangular pattern.
size (X) = max ((n ÷ gcd (b, n), (n ÷ gcd (d, n)))
And the size size (Y) in the main scanning direction Y of the rectangular pattern is
size (Y) = max ((n ÷ gcd (a, n), (n ÷ gcd (c, n))
By creating so that the rectangular pattern can be obtained, a rectangular pattern can be easily created, and a binarization pattern can also be easily created.
[0110]
Further, in a printing system or printing apparatus (printer or the like) that performs binarization based on the binarization pattern as described above, high-quality printing can be performed without noticeable dot deviation or moire.
(B) Other
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
[0111]
For example, in the above-described embodiment, the basic pattern is rotated by −θ, and the lighting order is set for the rotated basic pattern. However, the present invention is not limited to this, and the basic pattern is not rotated. Direct lighting order may be set.
Further, in the above-described embodiment, the lighting order determination unit 20 divides the basic pattern into two in the vertical direction with a horizontal line including the center point (specific point) as a boundary, and the upper half pixel and the lower half pixel. For example, the lighting order is set in order from the largest weight (W), but is not limited to this. For example, the basic pattern is changed to the right and left with a vertical line including a specific point as a boundary. The lighting order may be set in order from the pixel having the larger weight (W) alternately to the right half pixel and the left half pixel.
[0112]
Further, in the embodiment described above, the lighting order determination unit 20 determines the lighting order by calculating the weight (W) for the rotated basic pattern after rotating the basic pattern by −θ. However, it is not limited to this.
FIGS. 20A and 20B are diagrams for explaining a method of setting the lighting order without rotating the basic pattern by −θ, and FIG. 20A shows a state in which the lighting order is set halfway. FIG. 20B is a diagram showing a state in which the lighting order is set in the basic pattern.
[0113]
As shown in FIGS. 20A and 20B, the lighting order setting unit 20 may calculate the weight (W) of each pixel and set the lighting order without rotating the basic pattern by −θ. Good.
In addition, if each embodiment of this invention is disclosed, it can be manufactured by those skilled in the art.
[0114]
(C) Appendix
(Additional remark 1) It is the creation method of the pattern for binarization used for binarization of a multi-value image,
A basic pattern shape creation step for creating a basic pattern shape of the binarization pattern by calculation;
A lighting order determining step for determining a lighting order of pixels constituting the basic pattern;
A binarization pattern creation method comprising: a rectangular pattern creation step of creating a rectangular pattern that functions as the binarization pattern based on the basic pattern.
[0115]
(Additional remark 2) It is the creation method of the pattern for binarization used for the binarization of a multi-value image,
A basic pattern shape creating step for creating a basic pattern shape of the binarization pattern;
A lighting order determination step for determining the lighting order of pixels constituting the basic pattern by calculation;
A binarization pattern creation method comprising: a rectangular pattern creation step of creating a rectangular pattern that functions as the binarization pattern based on the basic pattern.
[0116]
(Supplementary Note 3) A method for creating a binarization pattern used for binarization of a multi-value image,
A basic pattern shape creation step for creating a basic pattern shape of the binarization pattern by calculation;
A lighting order determination step for determining the lighting order of pixels constituting the basic pattern by calculation;
A binarization pattern creation method comprising: a rectangular pattern creation step of creating a rectangular pattern that functions as the binarization pattern based on the basic pattern.
[0117]
(Supplementary note 4) The binarization pattern creation method according to any one of supplementary notes 1 to 3, wherein in the rectangular pattern creation step, the rectangular pattern is created by calculation.
(Supplementary Note 5) In the basic pattern shape creation step,
An angle designating step for designating an angle of the binarization pattern;
The basic pattern shape is calculated based on the pixel number designating step for designating the number of pixels constituting the basic pattern, the angle designated in the angle designating step, and the pixel number designated in the pixel number designating step. The binarization pattern creation method according to any one of appendix 1 to appendix 4, characterized by comprising a computation step to be created.
[0118]
(Supplementary Note 6) In the basic pattern shape creating step, the shape of the basic pattern is changed to any parameters a, b, c, d (provided that the number of pixels n = ad + bc specified in the pixel number specifying step) is satisfied. a square consisting of four points A (c, 1), B (a + c, b + 1), C (0, d + 1), and D (a, b + d + 1) specified by a, b, c, and d And, as the basic pattern, the one having the angle close to the angle of the binarization pattern designated in the angle designation step among the created squares is selected. The binarization pattern creation method according to appendix 5.
[0119]
(Supplementary Note 7) In the lighting order determination step,
The binarization pattern creation according to any one of appendix 1 to appendix 6, wherein the lighting order of the pixels is determined based on a distance between the pixel and a specific point in the basic pattern. Method.
(Supplementary Note 8) In the lighting order determination step,
The lighting order is determined so that the length of the boundary contour line between the lighting pixel and the non-lighting pixel is minimized in order from the pixel close to the specific point of the basic pattern. The method for creating a binarization pattern as described.
[0120]
(Supplementary Note 9) In the lighting order determination step,
The binarization pattern generation according to appendix 7 or appendix 8, wherein the lighting order of the pixels is determined based on a certain coefficient related to the distance between the pixel and a specific point in the basic pattern Method.
(Supplementary Note 10) In the lighting order determination step, the lighting order is determined based on a weight set by calculation for each pixel according to a distance between the pixel and the specific point in the basic pattern. The binarization pattern creation method according to Supplementary Note 2 or Supplementary Note 3, which is characterized.
[0121]
(Supplementary Note 11) In the rectangular pattern creation step,
Note that the rectangular pattern having a specific size is cut out as the binarization pattern from the continuous pattern formed by repeatedly arranging the basic patterns in the main scanning direction and the sub-scanning direction of the image. 1. The binarization pattern creation method according to any one of appendix 10.
[0122]
(Supplementary Note 12) In the rectangular pattern creation step,
12. The binarization pattern creation method according to appendix 11, wherein a partial pattern having the characteristics of the rectangular pattern is cut out from the rectangular pattern and the rectangular pattern is represented by the partial pattern.
(Supplementary note 13) The partial pattern is a rectangular region composed of Y × i pixels having a size Y in the main scanning direction and a size i in the sub-scanning direction.
The main scanning direction size Y is the main scanning direction size of the rectangular pattern given as the specific size,
The sub-scanning direction size i indicates that the area includes all kinds of lighting order values included in one basic pattern (the lighting order determined for all the pixels constituting the basic pattern in the lighting order determination step). The method for creating a binarization pattern according to appendix 12, characterized in that it is the minimum size (number of pixels) in the sub-scanning direction necessary for including the pixels to which the numerical values are assigned.
[0123]
(Supplementary Note 14) In the rectangular pattern creating step, the rectangular pattern has a size size (x) in the sub-scanning direction X of the rectangular pattern.
size (X) = max ((n ÷ gcd (b, n), (n ÷ gcd (d, n)))
And the size size (Y) in the main scanning direction Y of the rectangular pattern is
size (Y) = max ((n ÷ gcd (a, n), (n ÷ gcd (c, n))
7. The binarization pattern creation method according to appendix 6, wherein the pattern is created by calculation so that
[0124]
(Supplementary Note 15) A binarization pattern created based on a basic pattern and used for binarization of a multi-valued image,
Among the pixels constituting the basic pattern, the pixels are lit in order from the pixel closest to the specific point of the basic pattern so that the length of the boundary contour line between the lit pixel and the non-lit pixel is minimized. A binarization pattern characterized by generating continuous halftone dots.
[0125]
(Supplementary Note 16) The binarization method according to Supplementary Note 15, wherein the lighting order of the pixels is determined based on a certain coefficient related to a distance between the pixel and a specific point in the basic pattern. pattern.
(Supplementary Note 17) A rectangular binarization pattern created based on a basic pattern and used for binarization of a multi-valued image,
Each pixel of the partial pattern having the characteristics of the binarization pattern is turned on in a predetermined lighting order, and the halftone pattern is repeatedly arranged according to a predetermined rule to generate continuous halftone dots. Characteristic binarization pattern.
[0126]
(Supplementary Note 18) The partial pattern is a rectangular area composed of Y × i pixels having a size Y in the main scanning direction and a size i in the sub-scanning direction.
The main scanning direction size Y is the main scanning direction size of the binarization pattern given as the specific size,
For the sub-scanning direction size i, the area is assigned all kinds of lighting order values (numerical values indicating lighting orders determined for all pixels constituting the basic pattern) included in one basic pattern. 18. The binarization pattern according to appendix 17, characterized in that it is the minimum size (number of pixels) in the sub-scanning direction necessary for including the processed pixels.
[0127]
(Supplementary note 19) A binarization pattern creating apparatus for creating a binarization pattern used for binarization of a multi-valued image,
A basic pattern shape creation unit for creating a basic pattern shape of the binarization pattern by calculation;
A lighting order determining unit that determines the lighting order of pixels constituting the basic pattern by calculation;
A binarization pattern creating apparatus, comprising: a rectangular pattern creation unit that creates a rectangular pattern that functions as the binarization pattern based on the basic pattern by calculation.
[0128]
(Supplementary Note 20) The basic pattern shape creation unit is
An angle designating unit for designating an angle of the binarization pattern;
A pixel number designating unit for designating the number of pixels constituting the basic pattern;
The arithmetic unit for generating the basic pattern shape by calculation based on the angle specified by the angle specifying unit and the number of pixels specified by the pixel number specifying unit, Binarization pattern creation device.
[0129]
(Supplementary Note 21) The basic pattern shape creation unit may change the shape of the basic pattern into any parameters a, b, c, d (provided that the number of pixels n = ad + bc specified by the number-of-pixels specifying unit) , A, b, c, d are integers), and are composed of four points of point A (c, 1), point B (a + c, b + 1), C (0, d + 1), D (a, b + d + 1). It is created as a quadrangle, and among the created quadrilaterals, a pattern whose angle is close to the angle of the binarization pattern designated by the angle designation unit is selected as the basic pattern. 25. A binarization pattern creating apparatus according to appendix 20.
[0130]
(Supplementary Note 22) The lighting order determination unit
The binarization pattern creation according to any one of appendices 19 to 21, wherein the lighting order of the pixels is determined based on a distance between the pixel and a specific point in the basic pattern. apparatus.
(Supplementary Note 23) The lighting order determination unit
The lighting order is determined so that the length of the boundary contour line between the lighting pixel and the non-lighting pixel is minimized in order from the pixel close to the specific point of the basic pattern. The binarization pattern creation apparatus described.
[0131]
(Supplementary Note 24) The lighting order determination unit
The binarization pattern creation according to appendix 22 or appendix 23, wherein the lighting order of the pixels is determined based on a certain coefficient related to the distance between the pixel and a specific point in the basic pattern apparatus.
(Supplementary Note 25) The rectangular pattern creating unit
APPENDIX 19 to APPENDIX characterized by cutting out the rectangular pattern having a specific size as the binarization pattern from a continuous pattern formed by repeatedly arranging the basic patterns in the main scanning direction and the sub-scanning direction of an image. 25. The binarization pattern creating apparatus according to any one of 24.
[0132]
(Supplementary Note 26) The rectangular pattern creation unit
26. The binarization pattern creating apparatus according to appendix 25, wherein a partial pattern having the characteristics of the rectangular pattern is cut out from the rectangular pattern, and the rectangular pattern is represented by the partial pattern.
(Supplementary note 27) The partial pattern is a rectangular region composed of Y × i pixels having a size Y in the main scanning direction and a size i in the sub-scanning direction.
The main scanning direction size Y is the main scanning direction size of the rectangular pattern given as the specific size,
The sub-scanning direction size i indicates that the area includes all kinds of lighting order values included in one basic pattern (the lighting order determined by the lighting order determination unit for all the pixels constituting the basic pattern. 27. The binarization pattern creating apparatus according to appendix 26, characterized in that it is the minimum size (number of pixels) in the sub-scanning direction necessary for including the pixels each assigned with a numerical value.
[0133]
(Supplementary Note 28) The rectangular pattern creation unit determines that the rectangular pattern has a size size (x) in the sub-scanning direction X of the rectangular pattern.
size (X) = max ((n ÷ gcd (b, n), (n ÷ gcd (d, n)))
And the size size (Y) in the main scanning direction Y of the rectangular pattern is
size (Y) = max ((n ÷ gcd (a, n), (n ÷ gcd (c, n))
The binarization pattern creating apparatus according to appendix 21, wherein the pattern is created by calculation so that
[0134]
(Supplementary note 29) A binarization pattern creation program for causing a computer to execute a binarization pattern creation function used for binarization of a multi-value image,
A basic pattern shape creation unit for creating a basic pattern shape of the binarization pattern by calculation;
A lighting order determining unit that determines the lighting order of pixels constituting the basic pattern by calculation;
A binarization pattern creation program that causes the computer to function as a rectangular pattern creation unit that creates a rectangular pattern that functions as a binarization pattern by calculation based on the basic pattern.
[0135]
(Supplementary Note 30) The basic pattern shape creation unit is
An angle designating unit for designating an angle of the binarization pattern;
A pixel number designating unit for designating the number of pixels constituting the basic pattern;
The supplementary note 29, further comprising: a computing unit that creates the basic pattern shape by computation based on the angle designated by the angle designation unit and the number of pixels designated by the pixel number designation unit. Pattern creation program for binarization.
[0136]
(Supplementary Note 31) The basic pattern shape creation unit may change the shape of the basic pattern to any parameters a, b, c, and d that satisfy the condition of the pixel number n = ad + bc specified by the pixel number specification unit (provided that , A, b, c, d are integers), and are composed of four points of point A (c, 1), point B (a + c, b + 1), C (0, d + 1), D (a, b + d + 1). It is created as a quadrangle, and among the created quadrilaterals, a pattern whose angle is close to the angle of the binarization pattern designated by the angle designation unit is selected as the basic pattern. The binarization pattern creation program according to attachment 30.
[0137]
(Supplementary Note 32) The lighting order determination unit
32. The binarization pattern creation according to any one of appendix 29 to appendix 31, wherein a lighting order of the pixels is determined based on a distance between the pixel and a specific point in the basic pattern. program.
(Supplementary Note 33) The lighting order determination unit
The lighting order is determined so that the length of the boundary contour line between the lighting pixel and the non-lighting pixel is minimized in order from the pixel close to the specific point of the basic pattern. The binarization pattern creation program described.
[0138]
(Supplementary Note 34) The lighting order determination unit
34. The binarization pattern creation according to appendix 32 or appendix 33, wherein the lighting order of the pixels is determined based on a certain coefficient related to the distance between the pixel and a specific point in the basic pattern program.
(Supplementary Note 35) The rectangular pattern creating unit
APPENDIX 29 to APPENDIX characterized by cutting out the rectangular pattern having a specific size as the binarization pattern from a continuous pattern formed by repeatedly arranging the basic patterns in the main scanning direction and the sub-scanning direction of the image. 34. The binarization pattern creation program according to any one of 34.
[0139]
(Supplementary Note 36) The rectangular pattern creating unit
36. The binarization pattern creation program according to appendix 35, wherein a partial pattern having the characteristics of the rectangular pattern is cut out from the rectangular pattern and the rectangular pattern is represented by the partial pattern.
(Supplementary Note 37) The partial pattern is a rectangular area composed of Y × i pixels having a size Y in the main scanning direction and a size i in the sub scanning direction.
The main scanning direction size Y is the main scanning direction size of the rectangular pattern given as the specific size,
The sub-scanning direction size i indicates that the area includes all kinds of lighting order values included in one basic pattern (the lighting order determined by the lighting order determination unit for all the pixels constituting the basic pattern. 37. The binarization pattern creation program according to appendix 36, which is the minimum size (number of pixels) in the sub-scanning direction necessary for including the pixels to which the numerical values are assigned.
[0140]
(Supplementary Note 38) The rectangular pattern creation unit determines that the rectangular pattern has a size size (x) in the sub-scanning direction X of the rectangular pattern.
size (X) = max ((n ÷ gcd (b, n), (n ÷ gcd (d, n)))
And the size size (Y) in the main scanning direction Y of the rectangular pattern is
size (Y) = max ((n ÷ gcd (a, n), (n ÷ gcd (c, n))
The binarization pattern creation program according to appendix 31, wherein the binarization pattern creation program is created by calculation so that
[0141]
(Supplementary note 39) A computer-readable recording medium recording a binarization pattern creation program for causing a computer to execute a binarization pattern creation function used for binarization of a multi-value image,
The binarization pattern creation program is
A basic pattern shape creation unit for creating a basic pattern shape of the binarization pattern by calculation;
A lighting order determining unit that determines the lighting order of pixels constituting the basic pattern by calculation;
On the basis of the basic pattern, a binarization pattern creating program for causing the computer to function as a rectangular pattern creating unit that creates a rectangular pattern that functions as a binarization pattern by calculation. A recorded computer-readable recording medium.
[0142]
(Supplementary Note 40) The basic pattern shape creation unit is
An angle designating unit for designating an angle of the binarization pattern;
A pixel number designating unit for designating the number of pixels constituting the basic pattern;
The supplementary note 39, further comprising: an arithmetic unit that creates the basic pattern shape by calculation based on the angle specified by the angle specifying unit and the pixel number specified by the pixel number specifying unit. A computer-readable recording medium on which a binarization pattern creation program is recorded.
[0143]
(Supplementary Note 41) The basic pattern shape creation unit may change the shape of the basic pattern to any parameters a, b, c, d (provided that the number of pixels n = ad + bc specified by the number-of-pixels specifying unit) , A, b, c, and d are integers), and are composed of four points of point A (c, 1), point B (a + c, b + 1), C (0, d + 1), and D (a, b + d + 1). It is created as a quadrangle, and among the created quadrilaterals, a pattern having an angle close to the angle of the binarization pattern designated by the angle designation unit is selected as the basic pattern. A computer-readable recording medium on which the binarization pattern creation program according to appendix 40 is recorded.
[0144]
(Supplementary Note 42) The lighting order determination unit
42. The binarization pattern creation according to any one of appendix 39 to appendix 41, wherein the lighting order of the pixels is determined based on a distance between the pixel and a specific point in the basic pattern. A computer-readable recording medium on which a program is recorded.
[0145]
(Supplementary Note 43) The lighting order determination unit
The lighting order is determined in order from the pixels close to a specific point of the basic pattern so that the length of the boundary contour line between the lighting pixel and the non-lighting pixel is minimized. A computer-readable recording medium on which the binarization pattern creation program described is recorded.
[0146]
(Supplementary Note 44) The lighting order determination unit
44. The binarization pattern creation according to appendix 42 or appendix 43, wherein the lighting order of the pixels is determined based on a certain coefficient related to the distance between the pixel and a specific point in the basic pattern A computer-readable recording medium on which a program is recorded.
[0147]
(Supplementary Note 45) The rectangular pattern creating unit
(Supplementary note 39 to supplementary notes) characterized in that the rectangular pattern having a specific size is cut out as the binarization pattern from a continuous pattern formed by repeatedly arranging the basic patterns in the main scanning direction and the sub-scanning direction of an image. 45. A computer-readable recording medium on which the binarization pattern creation program according to any one of 44 is recorded.
[0148]
(Supplementary Note 46) The rectangular pattern creating unit
45. A binarization pattern creation program according to appendix 45, wherein a partial pattern having the characteristics of the rectangular pattern is cut out from the rectangular pattern and the rectangular pattern is represented by the partial pattern. Computer-readable recording medium.
[0149]
(Supplementary Note 47) The partial pattern is a rectangular region composed of Y × i pixels having a main scanning direction size Y and a sub scanning direction size i.
The main scanning direction size Y is the main scanning direction size of the rectangular pattern given as the specific size,
The sub-scanning direction size i indicates that the area includes all kinds of lighting order values included in one basic pattern (the lighting order determined by the lighting order determination unit for all the pixels constituting the basic pattern. 46. A computer recording the binarization pattern creation program according to appendix 46, characterized in that it is the minimum size (number of pixels) in the sub-scanning direction necessary for including the pixels assigned with A readable recording medium.
[0150]
(Supplementary Note 48) The rectangular pattern creation unit determines that the rectangular pattern has a size size (x) in the sub-scanning direction X of the rectangular pattern.
size (X) = max ((n ÷ gcd (b, n), (n ÷ gcd (d, n)))
And the size size (Y) in the main scanning direction Y of the rectangular pattern is
size (Y) = max ((n ÷ gcd (a, n), (n ÷ gcd (c, n))
A computer-readable recording medium on which the binarization pattern creation program according to appendix 41 is recorded, wherein the binarization pattern creation program according to appendix 41 is recorded.
[0151]
(Supplementary Note 49) A binarization processing unit that binarizes a multi-value image based on a binarization pattern;
A printing apparatus having an image forming unit that forms an image on a medium based on a binarization result performed by the binarization processing unit;
The binarization pattern is
The length of the boundary contour line between the lit pixel and the non-lit pixel is minimized in order from the pixel that is created based on the basic pattern and that is close to a specific point of the basic pattern among the pixels that constitute the basic pattern. Thus, a continuous halftone dot is generated by lighting up the pixel.
[0152]
(Supplementary Note 50) The binarization pattern is
50. The printing system according to appendix 49, wherein the lighting order of the pixels is determined based on a constant coefficient related to a distance between the pixels and a specific point in the basic pattern.
(Supplementary Note 51) A binarization processing unit that binarizes a multi-value image based on a binarization pattern;
A printing apparatus having an image forming unit that forms an image on a medium based on a binarization result performed by the binarization processing unit;
The binarization pattern is
A rectangular binarization pattern created based on a basic pattern,
Each pixel of the partial pattern having the characteristics of the binarization pattern is turned on in a predetermined lighting order, and the halftone pattern is repeatedly arranged according to a predetermined rule to generate continuous halftone dots. Characteristic printing system.
[0153]
(Supplementary Note 52) The partial pattern is a rectangular region composed of Y × i pixels having a size Y in the main scanning direction and a size i in the sub-scanning direction.
The main scanning direction size Y is the main scanning direction size of the binarization pattern given as the specific size,
For the sub-scanning direction size i, the area is assigned all kinds of lighting order values (numerical values indicating lighting orders determined for all pixels constituting the basic pattern) included in one basic pattern. 52. The printing system according to appendix 51, wherein the printing system has a minimum size (number of pixels) in the sub-scanning direction necessary for including the processed pixels.
[0154]
(Supplementary Note 53) A binarization processing unit that binarizes a multi-valued image based on a binarization pattern;
A printing apparatus comprising an image forming unit for forming an image on a medium based on a binarization result performed by the binarization processing unit,
The binarization pattern is
The length of the boundary contour line between the lit pixel and the non-lit pixel is minimized in order from the pixel that is created based on the basic pattern and that is close to a specific point of the basic pattern among the pixels that constitute the basic pattern. Thus, a continuous halftone dot is generated by lighting up the pixel.
[0155]
(Supplementary Note 54) The binarization pattern is
54. The printing apparatus according to claim 53, wherein the lighting order of the pixels is determined based on a certain coefficient related to a distance between the pixels and a specific point in the basic pattern.
(Supplementary Note 55) A binarization processing unit that binarizes a multi-valued image based on a binarization pattern;
A printing apparatus comprising an image forming unit for forming an image on a medium based on a binarization result performed by the binarization processing unit,
The binarization pattern is
A rectangular binarization pattern created based on a basic pattern,
Each pixel of the partial pattern having the characteristics of the binarization pattern is turned on in a predetermined lighting order, and the halftone pattern is repeatedly arranged according to a predetermined rule to generate continuous halftone dots. A printing device that is characterized.
[0156]
(Supplementary Note 56) The partial pattern is a rectangular region composed of Y × i pixels having a size Y in the main scanning direction and a size i in the sub-scanning direction.
The main scanning direction size Y is the main scanning direction size of the binarization pattern given as the specific size,
For the sub-scanning direction size i, the area is assigned all kinds of lighting order values (numerical values indicating lighting orders determined for all pixels constituting the basic pattern) included in one basic pattern. 56. The printing apparatus according to appendix 55, wherein the printing apparatus has a minimum size (number of pixels) in the sub-scanning direction necessary for including the processed pixels.
[0157]
【The invention's effect】
  As described in detail above, the binarization pattern creation method of the present invention,Printing deviceThe binarization pattern creation program has the following effects or advantages.
  (1) A rectangular pattern that functions as a binarization pattern based on the basic pattern by creating the basic pattern shape of the binarization pattern by calculation, determining the lighting order of the pixels constituting the basic pattern Since the binarization pattern is created by creating the binarization pattern, the binarization pattern can be easily created (claims 1 and 5).
[0158]
  (2) When creating the shape of the basic pattern, the angle of the binarization pattern is specified, the number of pixels constituting the basic pattern is specified, and the basic pattern shape is determined based on the specified angle and the number of pixels. Since it is created by calculation, a basic pattern shape having a desired angle and the number of pixels can be easily created.1, Claim 5).
[0159]
(3) When determining the lighting order, it is possible to easily create a centralized binarization pattern by determining the lighting order of the pixels based on the distance between the pixel and a specific point in the basic pattern. it can.
(4) When determining the lighting order, by determining the lighting order of the pixels based on the distance between the pixel and a specific point in the basic pattern and a certain coefficient related to the distance, With the angle maintained, the dot pattern can be smoothly changed from a circular shape to an elliptical shape, and a pattern for binarization that can make dot misalignment and moire inconspicuous can be created with less man-hours. can do.
[0160]
(5) When determining the lighting order, the lighting order is determined in order from the pixel closest to the specific point of the basic pattern so that the length of the boundary contour line between the lighting pixel and the non-lighting pixel is minimized. As a result, the dot gain is reduced and the color material paste is stabilized, so that the output quality is improved.
(6) When creating a rectangular pattern, a rectangular pattern of a specific size is cut out as a binarization pattern from a continuous pattern formed by repeatedly arranging basic patterns in the main scanning direction and sub-scanning direction of an image. Thus, a rectangular binarization pattern can be easily created.
[0161]
(7) When creating a rectangular pattern, a partial pattern having features of the rectangular pattern is cut out from the rectangular pattern, and the rectangular pattern is represented by the partial pattern, thereby reducing the size of the binarization pattern. Therefore, the memory area required for binarization and the area for storing the binarization pattern can be reduced, the processing speed can be improved, and the hardware manufacturing cost can be reduced. (Claim 4).
[0162]
(8) The partial pattern is a rectangular area composed of Y × i pixels having the main scanning direction size Y and the sub-scanning direction size i, and the main scanning direction size Y is a rectangular size given as a specific size. The size of the shape pattern is the main scanning direction size, and the sub-scanning direction size i is for all types of lighting sequence values included in one basic pattern (for all pixels constituting the basic pattern in the lighting sequence determination step). Since this is the minimum size (number of pixels) in the sub-scanning direction necessary for including each pixel assigned a numerical value indicating the determined lighting order), the size of the binarization pattern can be reduced. Therefore, the memory area required for developing the binarization pattern during binarization processing and the area for storing the binarization pattern can be reduced. It is possible to reduce the manufacturing cost of the other hardware can improve speed.
[0163]
  (9) A point in which the shape of the basic pattern is designated by arbitrary parameters a, b, c, d (where a, b, c, d are integers) that satisfy the condition of the designated number of pixels n = ad + bc A (c, 1), point B (a + c, b + 1),pointC (0, d + 1),pointCreate as a quadrangle consisting of four points D (a, b + d + 1), and select the created quadrangle having an angle close to the angle of the specified binarization pattern as the basic pattern. Thus, the shape of the basic pattern can be easily created, and thereby the binarization pattern can be easily created.(Claim 1, Claim 5).
[0164]
  (10) The lighting order can be easily set by determining the lighting order based on the weight set by calculation for each pixel according to the distance between the pixel and the specific point in the basic pattern. Thus, a binarization pattern can be easily created.
  (11) When the rectangular pattern has a size size (x) in the sub-scanning direction X of the rectangular pattern,
  size (X) = max ((n ÷ gcd (b, n), (n ÷ gcd (d, n)))
And the size size (Y) in the main scanning direction Y of the rectangular pattern is
  size (Y) = max ((n ÷ gcd (a, n), (n ÷ gcd (c, n))
By creating so that a rectangular pattern can be obtained, a rectangular pattern can be easily created, and thereby a binarization pattern can be easily created(Claim 2).
[0165]
(12) In a printing system or printing apparatus that performs binarization based on the binarization pattern as described above, it is possible to perform high-quality printing in which dot deviation and moire are not noticeable.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a binarization pattern creating apparatus using a binarization pattern creating method according to an embodiment of the present invention.
FIG. 2 is a diagram showing a hardware configuration of a binarization pattern creating apparatus using the binarization pattern creating method as one embodiment of the present invention.
FIG. 3 is a conceptual diagram of a general binarization process for a multi-valued image.
FIG. 4 is a diagram illustrating an example of the shape of a basic pattern.
5A is a diagram showing the shape of a quadrilateral ABCD by coordinate values, and FIG. 5B is a diagram showing the quadrilateral ABCD by pixels.
FIG. 6 is a flowchart for explaining a basic pattern shape creation method by a calculation unit;
FIG. 7 is a diagram showing an example in which the angle of a square halftone dot determined by parameters a, b, c, and d is compared with a predetermined angle.
FIG. 8 is a diagram illustrating an example of a lighting order of pixels.
FIG. 9 is a diagram illustrating an example in which the lighting order is set so that the length of the boundary contour line between the lit pixel and the non-lit pixel is minimized.
FIG. 10 is a diagram illustrating an example in which the lighting order is not set so that the length of the boundary contour line between the lit pixel and the non-lit pixel is minimized.
FIG. 11 is a flowchart for explaining a lighting order determination method by a lighting order determination unit;
FIGS. 12A and 12B are diagrams illustrating a state where the lighting order is set halfway, FIG. 12B is a diagram illustrating a state where the basic pattern is rotated by −θ, and FIG. 12C is a diagram illustrating setting the lighting order to the basic pattern; It is a figure which shows the state which carried out.
FIG. 13 is a flowchart for explaining another method for determining the lighting order by the lighting order determination unit;
FIG. 14 is a diagram illustrating an example of a rectangular pattern.
FIG. 15 is a flowchart for explaining a rectangular pattern creation method by a rectangular pattern creation unit;
16A is a diagram for explaining a basic pattern used for proof of a rectangular pattern, and FIG. 16B is a diagram showing an example in which the basic pattern is developed on a plane.
FIG. 17 is a flowchart for explaining a method by which a rectangular pattern creation unit cuts out a partial pattern;
FIG. 18 is a diagram illustrating an example of a partial pattern.
FIG. 19 is a flowchart for explaining a binarization pattern creation method as one embodiment of the present invention;
20A is a diagram showing a state in which the lighting order is set halfway, and FIG. 20B is a diagram showing a state in which the lighting order is set in the basic pattern.
[Explanation of symbols]
1 Binarization pattern creation device
10 Basic pattern shape creation part
11 Angle specification part
12 Pixel number designation part
13 Calculation unit
20 Lighting order determination unit
30 Rectangular pattern generator
50 CPU
51 display
52 Display controller
53 RAM
54 ROM
55 Storage device
56 bus
57 I / O controller
58 keyboard
59 mice
60 Printer
100 computer system

Claims (5)

A method for creating a binarization pattern used for binarization of a multi-value image,
A basic pattern shape creation step for creating a basic pattern shape of the binarization pattern by calculation;
A lighting order determining step for determining a lighting order of pixels constituting the basic pattern;
A rectangular pattern creating step for creating a rectangular pattern that functions as the binarization pattern based on the basic pattern;
In the basic pattern shape creation step,
An angle designating step for designating an angle of the binarization pattern;
A pixel number specifying step for specifying the number of pixels constituting the basic pattern;
A calculation step for calculating the basic pattern shape based on the angle specified in the angle specification step and the number of pixels specified in the pixel number specification step;
The shape of the basic pattern is designated by arbitrary parameters a, b, c, d (where a, b, c, d are integers) that satisfy the condition of the number of pixels n = ad + bc designated in the pixel number designation step. Is created as a quadrangle consisting of four points of point A (c, 1), point B (a + c, b + 1), point C (0, d + 1), and point D (a, b + d + 1). Of these, a binarization pattern creating method is characterized in that a pattern whose angle is close to the angle of the binarization pattern designated in the angle designation step is selected as the basic pattern. In the rectangular pattern creating step, the rectangular pattern is sized (x) in the sub-scanning direction X of the rectangular pattern.
size (X) = max ((n ÷ gcd (b, n), (n ÷ gcd (d, n)))
And the size size (Y) in the main scanning direction Y of the rectangular pattern is
size (Y) = max ((n ÷ gcd (a, n), (n ÷ gcd (c, n))
The binarization pattern creation method according to claim 1, wherein the pattern is created by calculation so that A binarization processing unit for binarizing a multi-valued image based on the binarization pattern;
A printing apparatus comprising an image forming unit for forming an image on a medium based on a binarization result performed by the binarization processing unit,
The binarization pattern is
In accordance with the gradation of the multi-valued pixel, which is created based on the basic pattern, among the pixels constituting the basic pattern, in order from a pixel close to a specific point of the basic pattern, and a lit pixel and a non-lit pixel, In order to minimize the length of the boundary contour line of the basic pattern, the basic pattern is divided into two parts vertically from the horizontal line including the specific point. A distance from a specific point of the pattern to each pixel constituting the basic pattern is expressed as a weighting factor W (W = p−q × cos α−r × cos β; where α and β are pixels forming the basic pattern shape. When the coordinates of the specific point are indicated by (x, y) and the coordinates of the specific point are indicated by (PXDOT, PYDOT), values represented as α = x−PXDOT, β = y−PYDOT And p, q, and r are real numbers that are not negative numbers, respectively, so that continuous halftone dots are generated by sequentially lighting pixels starting with the largest weight coefficient W. And a printing device. A binarization processing unit for binarizing a multi-valued image based on the binarization pattern;
A printing apparatus comprising an image forming unit for forming an image on a medium based on a binarization result performed by the binarization processing unit,
The binarization pattern is
A rectangular binarization pattern created on the basis of the basic pattern, and close to a specific point of the basic pattern among the pixels constituting the basic pattern according to the gradation of the multi-valued pixel In order from the pixel and above the basic pattern obtained by dividing the basic pattern into two vertically from the horizontal line including the specific point so that the length of the boundary contour line between the lit pixel and the non-lit pixel is minimized. Alternatingly for each pixel of the half and lower half, a distance from a specific point of the basic pattern to each pixel constituting the basic pattern is expressed as a weighting factor W (W = p−q × cos α−r × cos β; α and β indicate the coordinates of the pixels forming the basic pattern shape by (x, y) and α = x−PXDO when the coordinates of the specific point are indicated by (PXDOT, PYDOT). , Β = y−PYDOT, and p, q, and r are real numbers that are not negative numbers), and are configured to light up in order from the pixel having the largest weighting factor W. Among the continuous patterns in which the basic pattern is repeatedly arranged in the main scanning direction Y and the sub-scanning direction X of the multi-value image, the size size (x) in the sub-scanning direction X is
size (X) = max ((n ÷ gcd (b, n), (n ÷ gcd (d, n))), and the size size (Y) in the main scanning direction Y is
size (Y) = max ((n ÷ gcd (a, n), (n ÷ gcd (c, n))
A printing apparatus, characterized in that it is a partial pattern that is generated by extracting a rectangular area that has one or more of each of the lighting orders in the basic pattern extracted from the rectangular pattern. . A binarization pattern creation program for causing a computer to execute a binarization pattern creation function used for binarization of a multi-value image,
A basic pattern shape creation unit for creating a basic pattern shape of the binarization pattern by calculation;
A lighting order determining unit that determines the lighting order of pixels constituting the basic pattern by calculation;
Based on the basic pattern, let the computer function as a rectangular pattern creation unit that creates a rectangular pattern that functions as a binarization pattern by calculation,
When the computer functions as the basic pattern shape creation unit,
An angle designating unit for designating an angle of the binarization pattern;
A pixel number designating unit for designating the number of pixels constituting the basic pattern;
Based on the angle designated by the angle designation unit and the number of pixels designated by the pixel number designation unit, the computer is caused to function as a computation unit that creates the basic pattern shape by computation,
The shape of the basic pattern is determined by arbitrary parameters a, b, c, d (where a, b, c, d are integers) satisfying the condition of the pixel number n = ad + bc specified by the pixel number specifying unit. Created as a quadrangle consisting of four points, designated point A (c, 1), point B (a + c, b + 1), point C (0, d + 1), point D (a, b + d + 1), and the created quadrangle The computer is caused to function so as to select, as the basic pattern, an angle whose angle is close to the angle of the binarization pattern designated by the angle designation unit. Pattern creation program for valuation.

Images