JP2004054584A - Method and device for automatically adding line attribute - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To add/correct line attributes emphasizing an object with respect to line drawing configured of a two-dimensional free curve such as a curve computer-inputted with handwriting with no width by applying visually natural feelings in the same way as the similar line drawing is handwritten by a professional painter with an ink pen or brush. <P>SOLUTION: In this method for adding line attributes, the size of line attributes to be added to line drawing is preliminarily set corresponding to the kind of the line attributes to be added to the line drawing and the size of the curvature of the line drawing, and path data expressing the skeleton of an object are inputted, and the path data are automatically divided into a straight part and a curved part, and the curvature is calculated along the traveling direction of the curved part, and the preliminarily set line attributes are added to the path data according to the curvature along the traveling direction. <P>COPYRIGHT: (C)2004,JPO

Description

【数２】

尚、付加属性の大きさｆ（κ（ｓ））を付加する位置は、上記中心位置オフセット関数ｈ（ｓ）により、種々の位置に調節可能であるが、パスデータＣ（ｓ）の曲線部では、付加する線属性の位置は、パスデータの進行方向に垂直な方向であって、曲線部の外側にはみ出すように（１例を、図６及び図１０に示す）、左側又は右側の一方の側に寄せて付加すると、いわゆる、「入り」や「抜き」と共に、曲線を強調する強弱感を、自然な視覚感覚で付加でき、好ましい。
又、上記例では、パスデータに沿ったｓ＝ｎの位置での演算結果を、以下のように記憶する。
中心リストＴ（ｎ）　＝　Ｃ（ｓ）　　　・・・（１）
左端リストＬ（ｎ）　＝　Ｃｎｅｗ１　　　　・・・（２）
右端リストＲ（ｎ）　＝　Ｃｎｅｗ２　　　　・・・（３）
又は
左端リストＬ（ｎ）　＝　Ｃｎｅｗ２　　　　・・・（４）
右端リストＲ（ｎ）　＝　Ｃｎｅｗ１　　　　・・・（５）
尚、上記式２、式３と式４、式５の選択は、法線べクトルＮ（ｓ）の方向による。
【００１１】
ｅ２）　０．０　＜　ｆ（κ（ｓ））　＜　Ｗｍｉｎである、曲線部と直線部との接合部では、パスデータの法線方向に、以下の数３、数４で演算される大きさを付加する。
【数３】

【数４】

又、上述と同様にして、パスデータに沿ったｓ＝ｎの位置での演算結果を、式１〜式５により記憶する。
【００１２】
ｅ３）　０．０　＝　＜　ｆ（κ（ｓ））　である、直線部では、パスデータの法線方向に、以下の数５、数６で演算される大きさを付加する。
【数５】

【数６】

尚、付加属性の大きさｆ（κ（ｓ））を付加する位置は、上記中心位置オフセット関数ｈ（ｓ）により、種々の位置に調節可能であるが、パスデータＣ（ｓ）の直線部では、付加する線属性の位置は、パスデータの進行方向に垂直な方向に、左右対称となるように（１例を、図６に示す）付加すると、自然なバランス感覚を付加でき、好ましい。
又、上述と同様にして、パスデータに沿ったｓ＝ｎの位置での演算結果を、式１〜式５により記憶する。
【００１３】
上記段落１０乃至段落１２の処理を、パスデータＣ（ｎ）の始点（ｎ＝ｓ０）から終点（ｎ＝ｓｅ）まで、曲線の道のりｓに沿って繰り返す（ステップＳ１２）と、次に、左右端リストＬ（ｎ），Ｒ（ｎ）に登録した輪郭データの平滑化処理を行う（ステップＳ１４）。
かかる平滑化処理は、リストＬ（ｎ），Ｒ（ｎ）で表される輪郭線と、中心線Ｃ（ｎ）との、各位置ｎでの曲率べクトルの角度差、又は、内積を、始端から終端まで演算し、各べクトルの方向が、所定の値よりも大きく異なっていると判定される場合には、当該不一致部位の周囲の領域（近傍の区間）に対して、線の膨張量を平滑化し、輪郭線を滑らかにする。例えば、
各べクトルの方向が異なる不一致領域の輪郭線の区間を、Ｏ（ｓ）（リストＬ（ｎ）及びＲ（ｎ））とすると、先ず、中心線Ｃ（ｓ）との距離Ｄ（ｓ）を演算する。
Ｄ（ｓ）　＝　ｄｉｓｔ（Ｃ（ｓ）−Ｏ（ｓ））　　・・・（６）
又、中心線Ｃ（ｓ）から輪郭線Ｏ（ｓ）への、単位べクトルを、Ｖ（ｓ）に記憶する。
Ｖ（ｓ）　＝　ｕｎｉｔ−Ｖｅｃｔ（ｆｒｏｍＣ（ｓ）　ｔｏ　Ｏ（ｓ））　　・・・（７）
次に、平滑化フィルタＦ（ｓ）を、距離関数Ｄ（ｓ）に畳み込み演算する。
Ｄ（ｓ）ｎｅｗ　＝　Ｄ（ｓ）・ｃｏｎｖｏｌｕｔｉｏｎ・Ｆ（ｓ）　　・・・（８）
最後に、次式により、輪郭線の平滑化を、終了する。
Ｏ（ｓ）　＝　Ｃ（ｓ）　＋　Ｄ（ｓ）ｎｅｗ・Ｖ（ｓ）　　・・・（９）
例えば、図９に示すパラメータ調節メニュ−画面のスライド・バーＢ５を左右に移動させることにより、フィルタ関数Ｆ（ｓ）の平滑化範囲を調節可能であり（同図のＢ５では、現在、１０画素の範囲で、フィルタ演算するように設定されている）、又、図９に示すパラメータ調節メニュ−画面のスライド・バーＢ６を左右に移動させることにより、フィルタ関数Ｆ（ｓ）の最大重み係数を調節可能である（同図のＢ６では、現在、最大重み＝２．０で、フィルタ演算するように設定されている）。
【００１４】
次に、予め生成し登録しておいた濃度プロファイルに従って、付加属性の輪郭の内部領域を、指定された付加属性で塗りつぶす（ステップＳ１６）。しかして、登録濃度プロファイルには、以下の３種類のモードが、現在、用意されている。
ｇ１）　ｐａｉｎｔ＝１で、輪郭線内部の領域を、全て、指定された単一色で塗りつぶすモード。
ｇ２）　ｐａｉｎｔ＝２で、輪郭線内部の領域を、小領域Ｌ（ｎ）、Ｒ（ｎ）、Ｌ（ｎ＋１）、Ｒ（ｎ＋１）で分割し、かかる小領域単位で、図１３（Ａ）に示すような濃度プロファイル・パターンにマッピングし、アフィン（ａｆｆｉｎｅ）変換により、各小領域を、指定された濃度プロファイルで塗りつぶすモード。
ｇ３）　ｐａｉｎｔ＝３で、上記ｐａｉｎｔ＝２の濃度プロファイル情報を、３次元の高低情報（深さ情報）とみなし、輪郭線内部の領域を、小領域Ｌ（ｎ）、Ｒ（ｎ）、Ｌ（ｎ＋１）、Ｒ（ｎ＋１）で分割し、かかる小領域単位で、図１３（Ａ）に示すような深さパターンにマッピングし、アフィン（ａｆｆｉｎｅ）変換により、各小領域を、指定された３次元深さモデルに変換するモード。
【００１５】
全ての付加属性の輪郭の内部領域を、指定された付加属性で塗りつぶすと、塗りつぶし結果を、表示手段２４の画面へ表示する（ステップＳ１８）。
又、表示手段２４へ表示された塗りつぶし結果を観察し、関数ｆ（）、ｗ（）、ｇ（）、又は、ｈ（）を修正したい場合には（ステップＳ２０）、例えば、図９に示すパラメータ調節メニュ−画面を開き、所望の関数ｆ（）、ｗ（）、ｇ（）、又は、ｈ（）の調節用パラメータを修正し（ステップＳ２２）、上記ステップＳ６へ戻る。
更に、表示手段２４へ表示された塗りつぶし結果を観察し、関数ｆ（）、ｗ（）、ｇ（）、又は、ｈ（）の修正処理は不要であるが、変換され表示された線画の特定部位を局所的に修正処理したい場合には、例えば、表示された線画の該当する特定の局所部位を、ポインティング手段２６ａで局所的にタッチする（ステップＳ３０）と、表示された線画の特定の局所部位を、修正処理することが出来る。
具体的には、例えば、局所的にタッチされた線画のパスデータに対応する曲率関数κ（ｓ）や、規格化関数ｗ（ｌ（ｓ））を表示し（ステップＳ３２ａ）、該当する特定の局所部位の関数値κ（ｓ）やｗ（ｌ（ｓ））を、ポインティング手段２６ａで、増加、又は、減少せしめ、局所的にマニュアル修正処理し（ステップＳ３４ａ）、上記ステップＳ６へ戻り、上記処理を繰り返す。
又、局所的にタッチされた線画のパスデータに対応する曲率関数κ（ｓ）や、規格化関数ｗ（ｌ（ｓ））の表示はせずに、予め所定の修正量を設定登録しておき（ステップＳ３２ｂ）、該当する特定の局所部位の関数値κ（ｓ）やｗ（ｌ（ｓ））を、上記所定の修正量だけ、ポインティング手段２６ａでタッチした場合、自動的に、増加、又は、減少せしめ、局所的にマニュアル修正処理し（ステップＳ３４ｂ）、上記ステップＳ６へ戻り、上記処理を繰り返してもよい。
上記局所的修正処理により、「入り」、「抜き」感と共に、線画の強弱感の自然に強調された画像が、素人でも、名人並みの腕前で、短時間かつ容易に製作可能となる。
【００１６】
【実施例】
図１１の（Ａ）〜（Ｆ）に、非常に簡単な線画に対する、本発明の効果を示す。同図（Ａ）は、手書き入力した幅のないオリジナル線画（原画）であり、この線画に、一様な大きさ（太さ）の付加属性を付与すると、同図（Ｂ）の画像が得られるが、ぎこちなく不自然な感じの線画となっている。
又、本発明で提案する左右非対称な大きさの付加属性を原画に付与するため、オフセット関数ｈ（ｆ（κ（ｓ）））＝１．０で、付加属性の大きさｆ（κ（ｓ））を、原画に重ねて表示すると、同図（Ｃ）が得られ、その内部を、同一色で塗りつぶすと、同図（Ｄ）が得られる。
更に、本発明で提案する左右対称な大きさの付加属性を原画に付与するため、オフセット関数ｈ（ｆ（κ（ｓ）））＝０．０で、付加属性の大きさｆ（κ（ｓ））を、原画に重ねて表示すると、同図（Ｅ）が得られ、その内部を、同一色で塗りつぶすと、同図（Ｆ）が得られる。
【００１７】
次に、図１６の手書き入力した幅のないオリジナル線画（原画）に対する本発明の効果を示すと、この線画に、一様な大きさ（太さ）の付加属性を付与すると、図１７（Ａ）の画像が得られるが、どことなく不自然で、硬い感じの画像となっている。
又、本発明で提案する始端、終端を、漸増／漸減処理し、オフセット関数ｈ（ｆ（κ（ｓ）））＝０．０で、一様な大きさの付加属性を付与し、その内部を、同一色で塗りつぶすと、図１７（Ｂ）が得られ、曲線の強弱感は無いが、「入り」、「抜き」のある、画像が得られている。
次に、本発明で提案する左右非対称な大きさの付加属性を原画に付与するため、オフセット関数ｈ（ｆ（κ（ｓ）））＝１．０で、付加属性の大きさｆ（κ（ｓ））を、曲率κ（ｓ）に応じて付与し、その内部を、同一色で塗りつぶすと、図１８（Ａ）の画像が得られ、曲線の「入り」、「抜き」と共に、曲線の強弱感に富んだ、自然な視覚感のする画像が得られている。
更に、本発明で提案する左右対称な大きさの付加属性を原画に付与するため、オフセット関数ｈ（ｆ（κ（ｓ）））＝０．０で、付加属性の大きさｆ（κ（ｓ））を、曲率κ（ｓ）に応じて付与し、その内部を、同一色で塗りつぶすと、図１８（Ｂ）の画像が得られ、曲線の「入り」、「抜き」と共に、曲線の強弱感に富んだ、自然な視覚感のする別の画像が得られている。
更に又、本発明で提案する左右非対称な大きさの付加属性を原画に付与した場合の別の効果を観察するため、オフセット関数ｈ（ｆ（κ（ｓ）））＝１．０で、付加属性の大きさｆ（κ（ｓ））の最大値を、変化させ、その内部を同一色で塗りつぶした効果を観察すると、Ｗｍａｘ＝３画素に設定した場合、図１９（Ａ）に示す画像が得られ、Ｗｍａｘ＝５画素に設定した場合、図１９（Ｂ）に示す画像が得られた。図１９の結果からは、対象物により、最適な線幅があるように感じられる。
【００１８】
次に、表示手段２４へ表示された塗りつぶし結果を観察し、関数ｆ（）、ｗ（）、ｇ（）、又は、ｈ（）の修正処理は不要であるが、変換され表示された線画の特定部位を局所的に修正処理した例を、図２０及び図２１を参照して説明する。
先ず、図２０（Ａ）に示すパスデータＣ（ｓ）に対して、上述と同様にして、オフセット関数ｈ（ｆ（κ（ｓ）））＝１．０で、かつ、一様な濃度で内部領域を塗りつぶした例を、図２０（Ｂ）に示す。
続いて、例えば、表示された属性付加処理後の線画の該当する特定の局所部位を、ポインティング手段２６ａで局所的にタッチする（ステップＳ３０）と、表示された線画の特定の局所部位を含む２次元自由曲線に対応した規格化関数ｗ（ｌ（ｓ））が、表示され（ステップＳ３２ａ）、道のり関数ｌ（ｓ）の始端からほぼ中央中点付近までの関数ｗ（ｌ（ｓ））の形状を、ポインティング手段２６ａで、増加せしめ、図２１に示すような形状に、局所的にマニュアル修正処理を追加した（ステップＳ３４ａ）後、上記ステップＳ６へ戻り、上記処理を繰り返して、再び、属性付加した線画を表示手段２４に表示すると、図２０（Ｃ）に示すような画像が得られ、同様にして、所望の局所部位を、任意に増加／減少修正処理することが可能である。
【００１９】
次に、本発明の付加属性として濃度情報を付加した１例を、図２２乃至図２４を参照して説明すると、先ず、図示しない手書きの幅のない線画パスデータＣ（ｓ）に対して、上述と同様にして、オフセット関数ｈ（ｆ（κ（ｓ）））＝１．０で、かつ、一様な濃度で内部領域を塗りつぶした例を、図２２に示す。
続いて、例えば、図１３（Ａ）に示すような濃度パターンで、上記内部領域を塗りつぶすと、図２３に示すような濃度情報で内部領域を塗りつぶした画像が得られる。
更に、この濃度情報を、高さ情報（深さ情報）に変換して、斜め上方からの光源で、かかる３次元立体を照射し、得られる画像を、図２４に示す。
【００２０】
【発明の効果】
以上説明したように、本発明によれば、ＣＡＤデータ、２次元濃淡画像、ポインティング手段により手書きでコンピュータ入力した曲線等のコンピュータで人工的に生成し入力た２次元自由曲線からなる幅のない線画に対して、インクペンや筆で同様な線画を、プロの画家が手書きした場合に当該線画に付加できる線の幅、カラー、濃淡情報等の線属性と同様な見た目に自然な感じを与え、対象物を強調する線属性を自動的に付加し、又、自動付加後の線属性を局所的に容易に手動修正することができる。
従って、プロの画家にとっても、又、絵心のない普通の人にとっても、簡単で、操作しやすく、線属性の付加処理や、その修正処理が、直感的で、結果の非常に分かりやすい線属性付加方法及び装置を提供することができる。
【図面の簡単な説明】
【図１】本発明のシステム全体の構成の１例を示すブロック図である。
【図２】本発明の線属性付加工程の１例を示すフローチャートである。
【図３】本発明の線属性の大きさ変換関数ｆ（κ（ｓ））の１例を示す図である。
【図４】本発明の線属性の規格化関数ｗ（ｌ（ｓ））の１例を示す図である。
【図５】本発明の線属性の中心位置オフセット関数ｈ（ｆ（κ（ｓ））の１例を示す図である。
【図６】本発明の直線部と曲線部との境界段差の１例を示す図である。
【図７】本発明の直線部と曲線部との境界段差部を滑らかに接合した１例を示す図である。
【図８】本発明の直線部と曲線部との段差部接続関数ｇ（ｆ（κ（ｓ）））の１例を示す図である。
【図９】本発明のパラメータ設定メニュ−画面の１例を示す図である。
【図１０】本発明のパスデータＣ（ｓ）の１例を示す図である。
【図１１】本発明の線属性付加処理を、簡単な線画に対して、実施した１例を示す図である。
【図１２】本発明の法線べクトルＮ（ｓ）の１例を示す図である。
【図１３】本発明の濃度情報で輪郭線の内部を塗りつぶす処理の１例を示す図である。
【図１４】その濃度プロファイルの１例を示す図である。
【図１５】本発明の付加した線属性の修正処理の１例を示すフローチャートである。
【図１６】本発明の線属性付加処理を行う前のオリジナル線画の１例を示す図である。
【図１７】上記オリジナル線画に、均一な属性を付加した例（Ａ）、及び、「入り」、「抜き」のみが付加された例（Ｂ）である。
【図１８】上記オリジナル線画に、大きさが左右で不均一な強弱（ｈ（）＝１）のある属性を付加した例（Ａ）、及び、大きさが左右で均一な強弱（ｈ（）＝０）のある属性を付加した例（Ｂ）である。
【図１９】上記オリジナル線画に、大きさが３ピクセルで、左右で不均一な強弱のある属性を付加した例（Ａ）、及び、大きさが５ピクセルで、左右で不均一な強弱のある属性を付加した例（Ｂ）である。
【図２０】本発明の線属性付加後の、手動修正処理の１例を示す図である。
【図２１】その規格化関数ｗ（ｌ（ｓ））の手動修正後の１例を示す図である。
【図２２】本発明の別の線画に対して、均一な濃度情報の線属性を付加した１例を示す図である。
【図２３】上記均一な濃度情報に替えて、濃度プロファイル情報の線属性を付加した１例を示す図である。
【図２４】上記濃度プロファイル情報を深さ情報に変換して線属性を付加した１例を示す図である。
【符号の説明】
１０　コンピュータ・システム
１２　マイクロプロセッサ（ＭＰＵ）
１４　記憶手段（ＲＡＭ，ＲＯＭを含む）
１６　フレーム・メモリ
１８　入出力制御手段
２０　共通バス
２２　外部大容量記憶手段
２４　表示手段
２６ａ　ポインティング手段
２６ｂ　キーボード
２８　プリンタ
３０　スキャナ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for automatically adding a line attribute useful for adding a line attribute such as a dynamic expression of a line to a line drawing such as an animation image, which is similar to the case of drawing with an ink pen or a brush. The present invention also relates to a method of adding and modifying a line attribute useful for adding a line attribute such as a dynamic expression of a line to a line drawing such as an animation image, which is similar to the case of drawing with an ink pen or a brush. .
[0002]
[Prior art]
a1) U.S. Pat. No. 5,611,036 discloses a method and apparatus for assigning a shape and an attribute to an image object by Berend et al.
a2) U.S. Pat. No. 5,850,228 discloses a device for automatically extracting and converting character skeleton data and generating a character font by Hasegawa et al.
[0003]
[Problems to be solved by the invention]
In the method a1), the path data representing the skeleton and the attribute data to be added are completely independently defined, so that they have versatility, but it takes a long time to produce a line drawing. It is very difficult to give a satisfactory line attribute to a person with no pictorial heart.
Furthermore, in the method a2), since the path data represented by the skeleton is mainly for character data, there is a problem that it is difficult to apply directly to line drawings such as animations and cartoons.
Therefore, the present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to artificially generate a computer such as a CAD data, a two-dimensional gray-scale image, a curve input manually by a computer using an input device, or the like. When a similar line drawing is drawn by hand with an ink pen or a brush for a line drawing with no width generated and input, it looks natural like the line attributes such as line width, color, and shading information that can be added to the line drawing. It is an object of the present invention to provide a method and an apparatus for automatically adding a line attribute that emphasizes an object.
Further, the object of the present invention is to apply a similar method to a CAD image, a two-dimensional gray-scale image, and a line drawing without a width artificially generated and input by a computer, such as a curve manually input by a computer using an input device, using an ink pen or a brush. Gives a natural look to line attributes such as line width, color, shading information, etc. that can be added to the line drawing when handwriting the line drawing, adds a line attribute that emphasizes the object, and easily corrects it To provide a possible method.
[0004]
[Means for Solving the Problems]
The present invention relates to a method for automatically adding a line attribute.
Setting the type of the line attribute to be added to the line drawing in advance, and the size of the line attribute to be added according to the magnitude of the curvature of the line drawing;
Inputting path data representing the contour of the object;
Automatically dividing the path data into a straight line portion and a curved portion;
Calculating a curvature along the traveling direction of the curved portion,
Adding the preset line attribute to the path data in accordance with the curvature along the traveling direction.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an example of a computer system (including a personal computer, hereinafter abbreviated as a PC) 10 for realizing an automatic line attribute adding apparatus according to the present invention, and a microprocessor (hereinafter abbreviated as an MPU) 12. And a storage unit (including a RAM and a ROM) 14 for storing a program to be executed by the MPU 12 and data to be read and written, and an image to be displayed on the display unit 24 which is connected to a display unit 24 such as a CRT or a liquid crystal display unit. A frame memory 16 for storing data and an input / output control means 18 connected to an external input / output device for reading / writing and controlling the operation of the input / output device are mutually connected via an internal common bus 20. It has become so.
The input / output control means 18 includes external mass storage means 22 such as a hard disk, CD, MO, and DVD, and pointing means (coordinates) including a pen & tablet, a mouse, a track ball, and a joystick. Input means) 26a, a keyboard 26b for inputting numerical data, commands, control signals, and the like, a printer 28 for printing operation results, a scanner 30 for inputting color photographs and the like, and communication via a network such as a LAN or the Internet. The cursor symbol written in the frame memory 16 is designated on the screen of the display means 24 under the control of the MPU 12 in response to the coordinate data output from the pointing means 26a. Move to the position / direction that was set.
[0006]
In such a configuration, a method of automatically adding a line attribute according to the present invention will be described with reference to the flowchart of FIG. First, before inputting the path data C (s) representing the skeleton of the object, the following parameters / functions are initialized as initialization work (step S2). The initially set parameters / functions can be interactively modified later.
d1) A function f (κ () () that converts the line attribute to be added to the input line drawing into a transverse length (size) of the line attribute to be added according to the magnitude of the curvature κ (s) of the line drawing. s)) is set by a monotonically increasing function with the horizontal axis being the curvature κ (s), as shown in FIG. As the type of the line attribute, an attribute including at least one of line width, density information, and color information can be designated.
The function f (κ (s)) is proportional to the curvature κ (s), which is the reciprocal of the radius of curvature, and specifies the minimum size Wmin, the value κmin (s) at this time, and the maximum size Wmax. Then, the curvature κ (s) becomes the minimum value Wmin in the case of the value of κmin (s), monotonically increases, and can be specified by a curve that asymptotically approaches the maximum value Wmax. The slope of the monotonically increasing curve can be arbitrarily adjusted, and s is a path variable between the start point ss and the end point se of the path data.
For example, the monotonously increasing gradient of the function f (κ (s)) can be adjusted by moving the slide bar B2 on the parameter adjustment menu screen shown in FIG. 9 to the left or right, and the parameter shown in FIG. The maximum value Wmax of the function f (κ (s)) can be adjusted by moving the slide bar B3 on the adjustment menu screen to the left and right (the maximum value is set to 6.0 in B3 in the same figure). The minimum value Wmin of the function f (κ (s)) can be adjusted by moving the slide bar B4 on the parameter adjustment menu screen shown in FIG. The minimum value is set to 2.0).
d2) A normalization function w (l (s)) for the size function f (κ (s)) of the additional attribute is set as shown in FIG. This function w (l (s)) calculates the path variable s between the start point and the end point of the path data C (s) by 0.0 (= s, start point) and 1.0 (= s, end point). In the case of normalization, the value of the function w (l (s)) is gradually increased from 0.0 to a predetermined size (for example, = 1.0) at the start portion, and the predetermined size is set at the end portion. As shown in FIG. 4, the range in which the shape is gradually decreased from (for example, = 1.0) to 0.0 and the shape of the start end and the end is added is the start point of the path data C (s) and / or , As a percentage (%) of the entire distance between the end points.
For example, the range in which the function w (l (s)) increases / decreases can be adjusted by moving the slide bar B7 on the parameter adjustment menu screen shown in FIG. 9 to the left or right (in B7 in FIG. At the beginning, the range of 25% is gradually increased from 0.0 to 1.0, and at the end, the range of 25% is gradually reduced from 1.0 to 0.0, for example. To change the shapes of the start end and the end.) d3) The center position offset of the additional attribute in which the position to which the size function f (κ (s)) of the additional attribute is added is shifted in the transverse direction with respect to the traveling direction of the path variable s of the path data C (s). The function h (f (κ (s))) is set as shown in FIG.
In the linear portion of the path data C (s), the size f (κ (s)) of the line attribute to be added is added so as to be symmetrical with respect to a direction perpendicular to the traveling direction of the path data. (One example is shown in FIG. 6). In the curved part of the path data C (s), the size f (κ (s)) of the line attribute to be added is in a direction perpendicular to the traveling direction of the path data. On the other hand, it is preferable to add it to one of the left side or the right side which is the outside (an example is shown in FIG. 7).
For example, the offset amount of the function h (f (s)) can be adjusted by moving the slide bar B9 on the parameter adjustment menu screen shown in FIG. 9 left and right (in FIG. 9B, the function f ( The magnitude of the function h () is set by the ratio of κ (s)) to the minimum value Wmin. Currently, the ratio of the function h () = 1.0 * Wmin, The attribute value to be added is set to offset completely outside.)
d4) When the position at which the function f (κ (s)) of d1-3) is added is shifted in the transverse direction by different offset amounts in the linear part and the curved part of the path data C (s), respectively. A so-called step occurs at the joint between the straight line portion and the curved line portion of the path data C (s). The junction between the straight line portion and the curved line portion of the path data C (s) is changed so that such a step is eliminated and the joint portion between the straight line portion and the curved line portion of the path data C (s) changes smoothly and connects. The range fslide and the connection shape g (s) are set as shown in FIG.
For example, the range in which the function w (l (s)) increases / decreases can be adjusted by moving the slide bar B7 on the parameter adjustment menu screen shown in FIG. 9 to the left or right (in B7 in FIG. At the beginning, the range of 25% is gradually increased from 0.0 to 1.0, and at the end, the range of 25% is gradually reduced from 1.0 to 0.0, for example. To change the shapes of the start end and the end.)
[0007]
Thus, when the initial setting process is completed (when the default value is used, the above process S2 can be skipped), the path data C (s) expressing the skeleton (line drawing) of the object is then changed. The process proceeds to an input process (step S4).
For example, when a mouse is used as the pointing means 26a, by moving the slide bar B1 of the parameter adjustment menu screen shown in FIG. Adjustment is possible (in B1 in the figure, it is set so that a coordinate value is input for every 50). A conceptual diagram of a line drawing input by the pointing means 26a is shown in FIG. 10 (in FIG. 10, a free curve C (s) is one), and a simple sample example is shown in FIG. C (s) is shown in FIG. 16 and an example of an illustration is shown in FIG. 16 (in this figure, 13 free curves C (s) are shown).
The line drawing path data C (s) having no width is represented by a two-dimensional free curve, and s is a parameter of the curve. When the free curve is input as a sequence of points, the free curve passes through the sequence of points. Even if it is a curve, it may not be such a sequence of points and may be a curve input as a control node, and any one can be used as long as the curvature κ (s) can be calculated. In the following example, an example of a spline curve passing through the input point sequence is shown. In addition, a non-uniform relational B-spline (Non-Uniform Rational B-spline = NURBS) curve, Various curves are available, such as a Je curve and a composite curve connecting these curves continuously.
[0008]
When the input processing of the line image path data C (s) having no width is completed, next, the path data C (s) is discretized by a predetermined unit length from the start point to the end point (step S6). In the example of the free curve C (s) in FIG. 10, a predetermined unit length (for example, one pixel on the drawing screen) from the start point (s = s0) to the end point (s = se) of the path data C (s) In step S6, a discretization process is performed along the path s of the curve.
[0009]
Next, for the path data C (s) discretized by a predetermined unit length, the size f (κ (s)) of the additional attribute and the additional position are calculated by the following equations 1 to 6. (Step S8) Then, referring to the result of Step S8, the center position where the additional attribute is added and the left and right end positions are determined, and the center list T (n) and the left and right end list L (n), Register and store in R (n) (step S10). That is, the path data C (s) is automatically divided into a curved part, a straight part, and a joint part thereof according to the following conditions e1) to e3) according to the magnitude of the curvature function. .
First, when the curvature at the point C (s) is κ (s), and the normal direction of the road s is represented by a vector N (s) as shown in FIG. 12, the size of the additional attribute f (κ (s) ) Can be classified into the following three cases according to the magnitude of κ (s).
[0010]
e1) In the curved part where Wmin <f (κ (s)), a size calculated by the following equations 1 and 2 is added in the normal direction of the path data.
(Equation 1)

(Equation 2)

The position at which the size f (κ (s)) of the additional attribute is added can be adjusted to various positions by the center position offset function h (s), but the curve portion of the path data C (s) can be adjusted. Then, the position of the line attribute to be added is in a direction perpendicular to the traveling direction of the path data and protrudes outside the curved portion (one example is shown in FIGS. 6 and 10). Is preferable, because it is possible to add a dynamic sense of emphasizing a curve together with the so-called "enter" and "pull" with a natural visual sense.
In the above example, the calculation result at the position of s = n along the path data is stored as follows.
Center list T (n) = C (s) (1)
Left end list L (n) = Cnew1 (2)
Right end list R (n) = Cnew2 (3)
Or
Left end list L (n) = Cnew2 (4)
Right end list R (n) = Cnew1 (5)
The selection of the above formulas 2, 3 and 4 and 5 depends on the direction of the normal vector N (s).
[0011]
e2) At the junction of the curved part and the straight part, where 0.0 <f (κ (s)) <Wmin, the magnitude calculated by the following equations 3 and 4 in the normal direction of the path data Is added.
[Equation 3]

(Equation 4)

In the same manner as described above, the calculation result at the position of s = n along the path data is stored by Expressions 1 to 5.
[0012]
e3) In the linear portion where 0.0 = <f (κ (s)), a size calculated by the following Expressions 5 and 6 is added in the normal direction of the path data.
(Equation 5)

(Equation 6)

The position at which the size f (κ (s)) of the additional attribute is added can be adjusted to various positions by the center position offset function h (s), but the linear portion of the path data C (s) can be adjusted. Then, it is preferable to add a line attribute to be added symmetrically in the direction perpendicular to the traveling direction of the path data (one example is shown in FIG. 6), so that a natural sense of balance can be added.
In the same manner as described above, the calculation result at the position of s = n along the path data is stored by Expressions 1 to 5.
[0013]
When the processing of the above paragraphs 10 to 12 is repeated along the curve s from the start point (n = s0) to the end point (n = se) of the path data C (n) (step S12), The contour data registered in the end lists L (n) and R (n) are smoothed (step S14).
This smoothing process calculates the angle difference or inner product of the curvature vector at each position n between the contour lines represented by the lists L (n) and R (n) and the center line C (n). From the beginning to the end, if it is determined that the direction of each vector is significantly different from the predetermined value, the line expansion is performed on the area around the mismatched part (the neighborhood section). Smooth the volume and smooth the contours. For example,
Assuming that the section of the contour line of the non-coincidence area in which the direction of each vector is different is O (s) (lists L (n) and R (n)), first, the distance D (s) from the center line C (s) Is calculated.
D (s) = dist (C (s) -O (s)) (6)
Also, the unit vector from the center line C (s) to the contour line O (s) is stored in V (s).
V (s) = unit-Vect (fromC (s) to O (s)) (7)
Next, the smoothing filter F (s) is convolved with the distance function D (s).
D (s) new = D (s) · convolution · F (s) (8)
Finally, smoothing of the contour line is ended by the following equation.
O (s) = C (s) + D (s) new · V (s) (9)
For example, the smoothing range of the filter function F (s) can be adjusted by moving the slide bar B5 on the parameter adjustment menu screen shown in FIG. 9 to the left or right. Is set so as to perform the filter operation within the range of), and by moving the slide bar B6 of the parameter adjustment menu screen shown in FIG. 9 to the left and right, the maximum weight coefficient of the filter function F (s) can be changed. It is adjustable (in B6 in the figure, it is set so that the filter operation is performed with the maximum weight = 2.0 at present).
[0014]
Next, according to the density profile generated and registered in advance, the internal region of the outline of the additional attribute is painted with the specified additional attribute (step S16). Thus, the following three modes are currently prepared in the registered density profile.
g1) A mode in which all areas inside the outline are painted in a designated single color when paint = 1.
g2) When paint = 2, the area inside the contour is divided into small areas L (n), R (n), L (n + 1), and R (n + 1), and FIG. A mode in which each small area is filled with a designated density profile by affine transformation by mapping to a density profile pattern as shown in FIG.
g3) When paint = 3, the density profile information of paint = 2 is regarded as three-dimensional height information (depth information), and the area inside the contour is defined as small areas L (n), R (n), and L (n). (N + 1) and R (n + 1) are divided into small area units, mapped to a depth pattern as shown in FIG. 13 (A), and each small area is designated by designated affine (affine) transformation. Mode to convert to dimensional depth model.
[0015]
When the inner area of the outline of all the additional attributes is filled with the specified additional attribute, the result of the filling is displayed on the screen of the display unit 24 (step S18).
In addition, when the result of the filling displayed on the display means 24 is observed and the function f (), w (), g (), or h () is to be corrected (step S20), for example, as shown in FIG. The parameter adjustment menu screen is opened, the parameters for adjusting the desired function f (), w (), g (), or h () are corrected (step S22), and the process returns to step S6.
Further, the result of the filling displayed on the display means 24 is observed, and the correction processing of the functions f (), w (), g (), or h () is unnecessary. When it is desired to locally correct the part, for example, when the pointing part 26a locally touches a specific local part corresponding to the displayed line drawing (step S30), the specific local part of the displayed line drawing is touched. The site can be corrected.
Specifically, for example, a curvature function κ (s) and a normalization function w (l (s)) corresponding to the path data of the line drawing that is locally touched are displayed (step S32a), and the corresponding specific The function value κ (s) or w (l (s)) of the local part is increased or decreased by the pointing unit 26a, and locally manually corrected (step S34a), and the process returns to step S6. Repeat the process.
Also, the curvature function κ (s) and the normalization function w (l (s)) corresponding to the path data of the line drawing that has been locally touched are not displayed, and a predetermined correction amount is set and registered in advance. Every other step (step S32b), if the function value κ (s) or w (l (s)) of the corresponding specific local part is touched by the pointing unit 26a by the predetermined correction amount, the value is automatically increased. Alternatively, the number may be decreased and manual correction processing may be locally performed (step S34b), and the process may return to step S6 and repeat the above processing.
By the above-described local correction processing, an image in which the feeling of “drawing in” and “pulling out” and the feeling of the strength of the line drawing are naturally emphasized can be easily and quickly produced even by an amateur with the skill of a master.
[0016]
【Example】
FIGS. 11A to 11F show the effect of the present invention on a very simple line drawing. FIG. 7A shows an original line drawing (original image) having no width input by handwriting. When an additional attribute having a uniform size (thickness) is added to this line drawing, the image shown in FIG. However, it is awkward and unnatural line drawing.
In addition, in order to add the left-right asymmetric size of the additional attribute proposed in the present invention to the original image, the offset function h (f (κ (s))) = 1.0 and the additional attribute size f (κ (s )) Is superimposed on the original image, and FIG. 14C is obtained. When the inside is filled with the same color, FIG. 14D is obtained.
Further, in order to add the left-right symmetric size of the additional attribute proposed in the present invention to the original image, the offset function h (f (κ (s))) = 0.0 and the size of the additional attribute f (κ (s) )) Is displayed superimposed on the original image, and FIG. 17E is obtained. When the inside is filled with the same color, FIG.
[0017]
Next, the effect of the present invention with respect to the original line drawing (original image) having no width input by handwriting shown in FIG. 16 will be described. If an additional attribute having a uniform size (thickness) is added to this line drawing, FIG. ) Is obtained, but the image is somewhat unnatural and hard.
In addition, the start and end points proposed in the present invention are gradually increased / decreased, and an offset function h (f (κ (s))) = 0.0, and an additional attribute having a uniform size is given. Is painted in the same color, and FIG. 17 (B) is obtained, and an image with “in” and “out” is obtained although there is no sense of the strength of the curve.
Next, in order to add an additional attribute having a left-right asymmetric size proposed in the present invention to the original image, the offset function h (f (κ (s))) = 1.0 and the additional attribute size f (κ ( s)) is given according to the curvature κ (s), and the inside thereof is filled with the same color to obtain an image of FIG. 18A. An image with a strong visual sense and a natural visual feeling is obtained.
Further, in order to add the left-right symmetrical additional attribute proposed in the present invention to the original image, the offset function h (f (κ (s))) = 0.0 and the additional attribute size f (κ (s )) According to the curvature κ (s) and filling the inside with the same color, the image of FIG. 18 (B) is obtained, and the strength of the curve along with “enter” and “pull” of the curve Another image with a rich and natural visual feeling is obtained.
Furthermore, in order to observe another effect when the additional attribute of the left-right asymmetric size proposed in the present invention is added to the original image, the offset function h (f (κ (s))) = 1.0 Observing the effect of changing the maximum value of the attribute size f (κ (s)) and filling the inside with the same color, when Wmax = 3 pixels, the image shown in FIG. When Wmax = 5 pixels was obtained, the image shown in FIG. 19B was obtained. From the results in FIG. 19, it is felt that there is an optimum line width depending on the object.
[0018]
Next, the result of the filling displayed on the display means 24 is observed, and the correction processing of the functions f (), w (), g (), or h () is unnecessary. An example in which a specific part is locally corrected will be described with reference to FIGS.
First, for the path data C (s) shown in FIG. 20A, the offset function h (f (κ (s))) = 1.0 and uniform density FIG. 20B shows an example in which the internal area is filled.
Subsequently, for example, when the pointing device 26a locally touches a specific local part corresponding to the displayed line drawing after the attribute addition processing (step S30), the specific local part of the displayed line drawing including the specific local part is displayed. A normalized function w (l (s)) corresponding to the two-dimensional free curve is displayed (step S32a), and the function w (l (s)) from the starting point of the road function l (s) to near the center of the center is displayed. The shape is increased by the pointing means 26a, and a manual correction process is locally added to the shape as shown in FIG. 21 (step S34a). Then, the process returns to step S6, repeats the above process, and returns the attribute again. When the added line drawing is displayed on the display means 24, an image as shown in FIG. 20C is obtained. Similarly, it is possible to arbitrarily increase / decrease a desired local region. That.
[0019]
Next, an example in which density information is added as an additional attribute according to the present invention will be described with reference to FIGS. 22 to 24. First, with respect to unillustrated handwritten line drawing path data C (s) having no width. FIG. 22 shows an example in which the offset area h (f (κ (s))) = 1.0 and the internal area is painted with a uniform density in the same manner as described above.
Subsequently, for example, when the above-mentioned inner region is painted out with a density pattern as shown in FIG. 13A, an image in which the inner region is painted with the density information as shown in FIG. 23 is obtained.
Further, the density information is converted into height information (depth information), and the three-dimensional solid is irradiated with a light source obliquely from above, and an image obtained is shown in FIG.
[0020]
【The invention's effect】
As described above, according to the present invention, a line drawing without width consisting of a two-dimensional free curve artificially generated and input by a computer, such as CAD data, a two-dimensional grayscale image, and a curve manually input by a computer using a pointing means. When a professional artist paints a similar line drawing with an ink pen or a brush, it gives the same natural appearance as line attributes such as line width, color, and shading information that can be added to the line drawing. A line attribute that emphasizes an object can be automatically added, and the line attribute after the automatic addition can be locally and easily corrected manually.
Therefore, both for professional painters and for ordinary people without pictorial minds, the process of adding and modifying line attributes is intuitive and very easy to understand. An additional method and apparatus can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an example of the configuration of the entire system of the present invention.
FIG. 2 is a flowchart illustrating an example of a line attribute adding step according to the present invention.
FIG. 3 is a diagram illustrating an example of a size conversion function f (κ (s)) of a line attribute according to the present invention.
FIG. 4 is a diagram illustrating an example of a line attribute normalization function w (l (s)) according to the present invention.
FIG. 5 is a diagram illustrating an example of a center position offset function h (f (κ (s)) of a line attribute according to the present invention.
FIG. 6 is a diagram illustrating an example of a boundary step between a straight line portion and a curved portion according to the present invention.
FIG. 7 is a diagram showing an example of the present invention in which a boundary step portion between a straight line portion and a curved portion is smoothly joined.
FIG. 8 is a diagram illustrating an example of a step connection function g (f (κ (s))) between a straight line portion and a curved portion according to the present invention.
FIG. 9 is a diagram showing an example of a parameter setting menu screen of the present invention.
FIG. 10 is a diagram showing an example of path data C (s) of the present invention.
FIG. 11 is a diagram showing an example in which the line attribute addition processing of the present invention is performed on a simple line drawing.
FIG. 12 is a diagram showing an example of a normal vector N (s) of the present invention.
FIG. 13 is a diagram illustrating an example of a process of filling the inside of a contour line with density information according to the present invention.
FIG. 14 is a diagram showing an example of the density profile.
FIG. 15 is a flowchart illustrating an example of a process of correcting an added line attribute according to the present invention.
FIG. 16 is a diagram illustrating an example of an original line drawing before performing a line attribute adding process according to the present invention.
FIG. 17 shows an example (A) in which uniform attributes are added to the original line drawing, and an example (B) in which only “enter” and “pull” are added.
FIG. 18 shows an example (A) in which an attribute having strength (h () = 1) having unevenness in size is added to the original line drawing, and strength (h ()) having size uniform in left and right. = 0) is an example (B) in which an attribute is added.
FIG. 19 shows an example (A) in which an attribute having a size of 3 pixels and unevenness in the left and right directions is added to the original line drawing, and FIG. This is an example (B) in which an attribute is added.
FIG. 20 is a diagram illustrating an example of a manual correction process after adding a line attribute according to the present invention.
FIG. 21 is a diagram showing an example of the normalized function w (l (s)) after manual correction.
FIG. 22 is a diagram showing an example in which a line attribute of uniform density information is added to another line image of the present invention.
FIG. 23 is a diagram illustrating an example in which a line attribute of density profile information is added instead of the uniform density information.
FIG. 24 is a diagram showing an example in which the density profile information is converted into depth information and a line attribute is added.
[Explanation of symbols]
10 Computer system
12 Microprocessor (MPU)
14 Storage means (including RAM and ROM)
16 frame memory
18 I / O control means
20 common bus
22 External mass storage means
24 display means
26a pointing means
26b keyboard
28 Printer
30 Scanner

Claims (7)

A method for automatically adding line attributes,
Setting the type of the line attribute to be added to the line drawing in advance, and the size of the line attribute to be added according to the magnitude of the curvature of the line drawing;
Inputting path data representing the skeleton of the object;
Automatically dividing the path data into a straight line portion and a curved portion;
Calculating a curvature along the traveling direction of the curved portion,
Adding the preset line attribute to the path data in accordance with the curvature along the traveling direction. For the path data, a path between the start point and the end point of the path data is set as a variable, and a normalization function related to the size of the additional attribute is set.
The step of adding the preset line attribute to the path data in accordance with the curvature along the traveling direction, the step of correcting the size of the additional attribute by a normalization function relating to the size of the additional attribute 2. The method for automatically adding a line attribute according to claim 1, further comprising: Setting a center position offset function of the additional attribute to move the position of adding the size of the additional attribute,
The step of adding the preset line attribute to the path data according to the curvature along the traveling direction further includes a step of correcting a position at which the size of the additional attribute is added by the offset function. The method for automatically adding a line attribute according to claim 1. 4. The method according to claim 1, further comprising the step of adding the size of the line attribute to be added so that the size of the line attribute to be added is symmetric with respect to a direction perpendicular to the traveling direction of the line. Automatic addition method of line attribute described in. The automatic addition of the line attribute according to any one of claims 1 to 4, further comprising a step of correcting the size of the line attribute to be added to be continuous at a joint portion between the straight line portion and the curved portion. Method. The method according to claim 1, wherein the type of the line attribute includes at least one of line width, density information, and color information. The method according to any one of claims 1 to 6, wherein the line drawing is a cartoon or an animation image.

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