JP2004064426A - Image processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently detect a space between specific marks during image reading. <P>SOLUTION: In this image processing device, a mark detecting means scans sequentially input image data to detect a specific mark, and a space detecting means detects a space among a plurality of detected specific marks. A converting means converts a predetermined value into a natural number fold of n-th power of 2, and a comparing means compares the space detected by the space detecting means with a setup value converted by the converting means and discriminates whether it is a specified value or its natural number fold. <P>COPYRIGHT: (C)2004,JPO

Description

【００２９】
具体的には、図９に示す間隔検出回路を用いる。この間隔検出回路では、マークエレメントの間隔は以下のように検出する。まず、２００ｄｐｉ時の間隔を選択する。２５ｄｐｉ換算時に、表１のエレメント間隔と計算時のパラメータＶａｌｕｅを参照して、２５ｄｐｉでの間隔ｗにＶａｌｕｅを乗じる。次に、４ビット右にシフトして、１６での除算を行う。そして、下位のｎビット（３、４、５または６ビット）の数値を検査する。
【００３０】
具体的に説明すると、ＣＰＵ５０が、処理回路１００にパラメータＮを設定すると、エレメント間隔算出回路１０４内において、設定値保持部１１２は、それに対応して２５ｄｐｉでの画素数の設定値を保持する。（たとえば表１のＮ＝９の場合は４０という値を選択する。）次に、係数選択部１１６は、テーブル１１４を参照して、係数Ｖａｌｕｅを選択する。（たとえば表のＮ＝９の場合は１３という値を選択する。）一方、Ｘ座標カウンタ１１８は、Ｘ方向のカウンタであり、初期化の後で、基準となる信号をカウントし、カウント結果を２００ｄｐｉで出力する。差分算出部１２０は、前に検出されたエレメントのＸ座標ＰｒｅＸとカウンタ１１８との差分を求め、２００ｄｐｉでのエレメント間隔ｗを算出する。乗算器１２２は、係数Ｖａｌｕｅとエレメント間隔ｗとを乗算する。同時に、解像度変換のための３ビット及び１６での除算のための４ビットの合計７ビットを右にシフトする。（こうして、乗算器１２２は、ｗ＊Ｖａｌｕｅ／１６を出力する。）比較部１２４は、乗算結果の所定数の下位ビット（たとえば表のＮ＝９の場合は下位４ビット）が０（または±１）であるか否かを比較する。ここで±１は許容範囲を示す。最初のマークエレメントを検出した場合、または、最初のマークエレメントでなく前のエレメントとの間隔が規定値である場合、その結果を検出数カウント部１５５を含む検出回路と保持部１２６に送る。検出数カウント部１５５は検出数を１つ増加する。また、保持部１２６は、比較部１２４でエレメント検出を行った場合、１つ前の検出座標ＰｒｅＸとしてそのＸ座標を保持する。保持部１２６の検出座標は差分算出部１２０に送られる。
【００３１】
処理回路１００内のマーク判定回路１０２では、ＣＰＵ５０から入力されるＸ検出範囲とＹ検出範囲を設定保持部１５１に記憶しておく。特定マークの判定は、副走査有効領域信号と主走査有効領域信号が出力されているときの画像信号を受け取って進められる。Ｙ座標カウンタ１５０は、初期化の後で、副走査有効領域信号が出力されているときにＹ座標をカウントし、Ｘ座標カウンタ１１８は、主走査有効領域信号が出力されているときにＸ座標をカウントする。有効領域信号生成回路１５２は、Ｘ検出範囲及びＹ検出範囲と主走査有効領域信号とを基に有効領域信号を生成する。エレメント判定回路１５３は、有効領域信号が出力されているときに、画像データを入力してパターンマッチングによりマークエレメントを判定して、判定結果を出力する。
【００３２】
処理回路１００内のマーク判定回路１０２では、カウントアップ数判定部１５４は、マーク判定回路１０２からのマークエレメントの判定結果、エレメント間隔算出回路１０４からの間隔判定結果、及び、保持部１５６からのＰｒｅＦｌａｇとから、判定されたマークエレメントの有効／無効を判定する。検出判定部１５７は、マークエレメントの判定結果、間隔判定結果および保持部１５６で保持しているＰｒｅｆｌａｇから、マークエレメント候補が検出されたことを示すフラグＰｒｅＦｌａｇを立てる。検出数カウント部１５５は、マークエレメントの判定結果を基にマークエレメント検出数ｎＣｏｕｎｔを出力する。カウントアップ数判定部１５４と検出判定部１５７の処理内容は、後で図１２を用いて説明される。
【００３３】
次に、処理回路１００内の比較部１２４における処理について表１を参照して説明する。（１）もし２００ｄｐｉでの間隔が６４ドットまたは９６ドットであれば、下位３ビットが検査される。もし（ｗ　＆　０ｘ７）　が　０ｘ１、０ｘ０または０ｘ７ならば、すなわち、下位３ビットが００１、０００または１１１ならば、ＯＫである。（２）また、もし２００ｄｐｉでの間隔が１２８ドットから２２４ドットまでならば、下位４ビットが検査される。もし、（ｗ　＆　０ｘｆ）　が　０ｘ１、０ｘ０または０ｘｆならば、すなわち、下位４ビットが０００１、００００または１１１１ならば、ＯＫである。（３）また、もし２００ｄｐｉでの間隔が２５６ドットから４８０ドットまでならば、下位５ビットが検査される。もし、（ｗ　＆　０ｘ１ｆ）　が　０ｘ１、０ｘ０または０ｘ１ｆならば、すなわち、下位５ビットが００００１、０００００または１１１１１ならば、ＯＫである。（４）また、もし２００ｄｐｉでの間隔が５１２ドットならば、下位６ビットが検査される。もし、（ｗ　＆　０ｘ３ｆ）　が　０ｘ１、０ｘ０または０ｘ３ｆならば、すなわち、下位６ビットが０００００１、００００００または１１１１１１ならば、ＯＫである。
【００３４】
なお、パラメータＮは、画像処理装置が搭載される装置の機種に応じて自動的に設定してもよい。図１０は、その場合の設定値自動設定のフローチャートである。特定マーク認識チップ２８が画像処理装置に装着されている場合（Ｓ６０でＹＥＳ）、機種を識別し、装置が機種Ａであれば（Ｓ６２でＹＥＳ）、パラメータを示すＮ（表１）を１とする（Ｓ６４）。また、装置が機種Ｂであれば（Ｓ６６でＹＥＳ）、パラメータを示すＮを２とする（Ｓ６８）。以下、同様に機種に応じてＮを設定する。
【００３５】
以下に、特定マーク認識チップ２８における処理手順を説明する。図１１は、複数の特定マークからなるパターンの認識の処理のフローを示す。まずＲ，Ｇ，Ｂの画像データ（各８ビット）をエレメント判定回路１５３に入力する（Ｓ１００）。次に、入力画像データからＧＣマークの色を抽出する（Ｓ１０２）。エレメント判定回路１５３では、入力されたＲ，Ｇ，Ｂの画像濃度が、予め規定された参照濃度範囲内であるか否かを判定して２値化を行う。これにより２値データが得られる。次に、２値像データからノイズを除去する（Ｓ１０４）。ここで、１画素からなる孤立点を除去する。次に、こうして得られた２値データについて、パターンマッチングのためのマーク検出パラメータを用いて、特定マークエレメント形状を検出する（Ｓ１０６）。ここで、たとえば１１×１１画素のエレメントフィルタを用いてマークエレメント形状の抽出を行う。次に、検出判定部１５７において、検出したマークエレメントについて所定間隔であるか否かを検査する（Ｓ１０８）。ここで、前回検出されたマークエレメントのｘ座標位置ＰｒｅＸとの差が指定のマークエレメント間隔の自然数倍であればマークエレメントであると判定する。次に、検出数カウント部１５５において、所定間隔であるマークエレメントの個数を算出する（Ｓ１１０）。そして、マークエレメントの個数を合計し、規定数であるか否かを判定し、その結果を出力する（Ｓ１１２）。ここで、マークエレメントの個数が規定数であると、世代コピーであると判定する。
【００３６】
図１２は、特定マーク認識チップ２８におけるマーク間隔検査（図１１、Ｓ１０８）とマーク個数カウント（図１１、Ｓ１１０）のより詳細な処理を示す。ここで、画像データからの特定マークの検出は原稿の端から指定ライン数の範囲で行う。先に説明したように、特定マークは所定間隔で配置されているものとする。入力画像データを順次走査して、エレメント判定回路１５３が特定マークのパターンを検出する。２値データの座標位置は（Ｘ、Ｙ）で表わす。まず、前処理として、ＣＰＵ５０は、Ｘ検出範囲とＹ検出範囲とを設定値保持回路１５１に設定する。また、マークエレメント規定間隔を保持回路１１２に設定する。なお、有効領域であれば有効領域信号生成回路１５２が有効領域信号を出力する。副走査有効領域信号がＨレベルになると、検出数カウント部１５５において検出マークエレメント数ｎＣｏｕｎｔを０に初期化し、Ｙ座標カウンタ１５０においてＹ座標の値を０に初期化する（Ｓ２００）。次に、主走査有効領域信号がＨレベルになると、Ｘ座標カウンタ１１８においてＸ座標の値を０に初期化する（Ｓ２０２）。次に、エレメント判定回路１５３では、１１×１１画素のマークエレメントフィルタを用いて、パターンマッチングによりマークエレメント候補を検出する（Ｓ２０４）。マークエレメント候補が検出されると、次に、検出判定部１５７で最初のマークエレメントであるか否かを判定する（Ｓ２０６）。最初のマークエレメントであれば、検出数カウント部１５５では検出マークエレメント数ｎＣｏｕｎｔをインクリメントし、検出判定部１５７ではマークエレメント候補が検出されたことを示すフラグＰｒｅＦｌａｇを立てる（Ｓ２０８）。さらに、検出されたマークエレメントの中心のＸ座標をｘ１とし、現在のＸの値を、座標保持部１２６の前回検出マークエレメント位置ＰｒｅＸに設定する（Ｓ２２２）。また、マークエレメント候補が最初のマークエレメントでなければ（Ｓ２０６でＮＯ）、そのマークエレメントのＸ座標をｘ２とする。次に、そのマークエレメントと１つ前の検出マークエレメント位置ＰｒｅＸとの距離（ｘ２とｘ１の差の絶対値）が指定の間隔Ｗの自然数倍であるか否かを比較部１２４における下位ビットの比較により判定する（Ｓ２１０）。ここで、先に説明したように、テーブル１１４から選択された係数を用いた乗算値が用いられる。指定の間隔Ｗの自然数倍であれば（すなわちａｂｓ（ｘ２−ｘ１）＝ｎＷ±１ならば）、検出数カウント部１５５において検出マークエレメント数ｎＣｏｕｎｔをインクリメントする（Ｓ２１２）。ここで±１は許容範囲を示す。カウントアップ数判定部１５４は、カウントするべき場合に検出数カウント部１５５に信号を出力する。検出判定部１５７で出力されたフラグＰｒｅＦｌａｇが０であれば（Ｓ２１４でＹＥＳ）、検出数カウント部１５５において検出マークエレメント数ｎＣｏｕｎｔをインクリメントして（Ｓ２１６）、前回にマークエレメント候補でないと判断されたマークエレメント候補も検出マークエレメントとして扱う。そして、保持部１５６ではフラグＰｒｅＦｌａｇを１とする（Ｓ２１８）。また、エレメント検出座標保持部１２６において現在のＸ座標の値を前回検出マークエレメント位置ＰｒｅＸに設定する（Ｓ２２２）。指定の間隔Ｗでなければ（Ｓ２１０でＮＯ）、保持部１５６ではフラグＰｒｅＦｌａｇを０とする（Ｓ２２０）。また、保持部１２６において現在のＸの値を前回検出マークエレメント位置ＰｒｅＸに設定する（Ｓ２２２）。
【００３７】
次に、Ｘ座標カウンタ１１８ではＸをインクリメントして主走査方向に位置を移動し（Ｓ２２４）、ＸがＸ検出範囲内であれば（Ｓ２２６でＮＯ）、ステップＳ２０４に戻ってマークエレメント検出を続ける。
【００３８】
ＸがＸ検出範囲内でなくなると（Ｓ２２６でＹＥＳ）、Ｙ座標カウンタ１５０ではＹをインクリメントして、副走査方向に位置を移動する（Ｓ２２８）。ＹがＹ検出範囲内であれば（Ｓ２３０でＮＯ）、ステップＳ２０２に戻ってマークエレメント検出を続ける。ＹがＹ検出範囲内でなくなると（Ｓ２３０でＹＥＳ）、処理を終了する。このときのｎＣｏｕｎｔの値が、検出されたマークの数である。
【００３９】
図１３は、マーク個数カウント動作の例を示す。この例では長方形で示すマークエレメント候補が図に示すような順番で検出されている。最初のマークエレメント候補が検出されると、検出エレメント数ｎＣｏｕｎｔが１となり、フラグＰｒｅＦｌａｇが１と設定される。次に、２つ目のマークエレメント候補が検出されるが、指定の間隔の位置に存在しないので、マークエレメントでないと判断する。そこでフラグＰｒｅＦｌａｇが０に設定される。次に、３つ目のマークエレメント候補が検出されが、指定の間隔の位置に存在しないので、エレメントでないと判断し、フラグＰｒｅＦｌａｇが０に設定される。４つ目のマークエレメント候補が検出されると、指定の間隔の位置に存在するので、検出エレメント数ｎＣｏｕｎｔが２となり、さらに、前回のエレメント候補が指定の間隔でないと判断されていたので、有効なエレメント候補と判断して、さらに検出エレメント数ｎＣｏｕｎｔが３と増加する。そしてフラグＰｒｅＦｌａｇが１と設定される。
【００４０】
【発明の効果】
複数のマークからなるパターンの検出において、マーク間隔が設定値またはその自然数倍であるか否かを判別するので、比較手段が１つだけでよく、マーク間隔検出の構成が大幅に簡素化できる。
２のｎ乗の自然数倍に変換するので、比較手段で比較するビット数も少なくてすむ。
設定値を設定する設定手段を備えることにより、設定値がたとえば機種ごとに設定できる。
【図面の簡単な説明】
【図１】第１世代コピーの処理を示すフローチャート
【図２】世代コピーの１例の図
【図３】第２世代コピーの処理を示すフローチャート
【図４】認識に必要なラインを示す図
【図５】原稿の異なる置き方の場合の検出処理を示す図
【図６】カラー複写機の全体構成を示すブロック図
【図７】主走査方向に等間隔に配置されたマークエレメントの間隔を比較する比較例の図
【図８】主走査方向に等間隔に配置されたマークエレメントの間隔を比較する回路の概念を示す図
【図９】マークエレメント間隔検出回路の回路図
【図１０】画像処理装置が搭載される機種に応じた設定値自動設定のフローチャート
【図１１】特定マーク認識チップにおける特定マーク認識のフローチャート
【図１２】マーク間隔検査とマーク個数カウントのフローチャート
【図１３】マーク個数カウント動作の説明のための図
【符号の説明】
１０　ＣＣＤセンサ、　　２２　ＧＣマーク除去部、　　２４　特定原稿認識回路、　　２８　特定マーク認識チップ、３０　シャープネス補正部、　　３２ＨＶＣ調整部、　　３４　色空間変換部、　　３６　付加処理部、　　５０　ＣＰＵ、　　１００　処理回路、　　１０２　マーク判定回路１０２、　　１０４　エレメント間隔算出回路、　　１０６　総合判定回路、　　１１２　設定値保持部、　　１１６　係数選択部、　　１１８　Ｘ座標カウンタ、　　１２０　差分算出部、　　１２２　乗算器、　　１２４　比較部、　　１２６　保持部、１５３　ジェネレーションマークエレメント判定部、　　１５４　カウントアップ数判定部、　　１５５　検出数カウント部、　　１５７　　検出判定部。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the addition of a specific mark in original image data.
[0002]
[Prior art]
One direction of high image quality in an image forming apparatus such as a copying machine is to improve image reproducibility by performing image processing in accordance with the type of a document. Here, it has been proposed that a specific mark or the like is recorded on a sheet, and image processing is controlled based on information obtained by reading the mark.
[0003]
For example, in Japanese Patent Application Laid-Open No. 2001-189865, a copy prohibition mark or a bar code is recorded on a sheet to prevent illegal copying. When the image processing circuit detects a copy prohibition mark or barcode in the image data, it performs an appropriate process based on the obtained information (copy prohibition or the like). In Japanese Patent Application Laid-Open No. 8-3055791, a mark is formed on a sheet, and information is obtained from the mark. The information provided by the mark is various control information such as the direction of the document and the scanning direction. Here, by forming marks at the four corners of the sheet, the same recognition processing method can be used regardless of how the document is placed.
[0004]
[Problems to be solved by the invention]
As described above, it has been proposed to form an image by adding a specific mark representing information on the image to the original image. For example, in a so-called generation copy in which a copy is made as an original, so-called generation copy deteriorates the image quality of the original, so that an operator manually switches image processing to improve image reproducibility. Have been. In the case of generation copy, for example, characters tend to be thinned or rattled due to MTF characteristics. Therefore, character images are reproduced by performing expansion processing or performing image processing to emphasize edges more than in other cases. Performance can be improved. Therefore, it is conceivable that a specific mark invisible to human eyes is added to the original image in the generation copy so that it is possible to automatically determine whether or not the copy is an original. This makes it possible to automatically perform image processing suitable for generation copy simply by reading the document image. It is preferable that the specific mark itself does not affect the original image, and it is desired that the specific mark be small and hard to be recognized by human eyes. The present applicant, as proposed later, arranges a plurality of small and indistinguishable color marks, detects the marks themselves, and identifies the distance between the marks, thereby identifying a different image from the original image. Identify the mark. Here, it is desirable that the addition of the specific mark to the image at the time of image formation and the identification of the specific mark at the time of image reading can be performed effectively.
[0005]
An object of the present invention is to effectively identify a plurality of marks when reading an image.
[0006]
[Means for Solving the Problems]
An image processing apparatus according to the present invention includes a mark detection unit that sequentially scans input image data to detect a specific mark, an interval detection unit that detects an interval between a plurality of detected specific marks, and a predetermined value. A conversion unit for converting to a natural number multiple of 2 to the power of n, and comparing the interval detected by the interval detection unit with a set value converted by the conversion unit to determine whether the interval is a designated value or a natural number multiple thereof. And comparing means for determining
[0007]
In the image processing apparatus, for example, the conversion unit multiplies the set value by a coefficient corresponding to the set value to convert the set value to a natural number multiple of 2 n.
[0008]
The image processing apparatus preferably further includes a setting unit for setting the set value. For example, the set value may be automatically set according to the model in which the image processing apparatus is mounted.
[0009]
Preferably, the image processing apparatus further includes an image processing unit that performs predetermined image processing on the input image data when the mark is detected. This image processing means, for example, when the mark is detected, recognizes that the document is a specific document, and performs image processing suitable for generation copying.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
A generation copy (generation copy) is to copy a copy as a document. In the present invention, when printing an original with a color copying machine or a multi-function multifunction peripheral, a pattern formed of a mark of a specific shape is used so that it is possible to determine whether or not the copy is an original. Copying is performed by adding to the original image. When an image is read using a copy to which a pattern including a plurality of specific marks is added as an original and an image is formed on a sheet, the pattern of the specific mark can be detected from image data obtained by reading the original. Thus, it can be automatically determined that the copy is a generation copy. If it is determined that the copy is a generation copy, image processing suitable for such a document is performed to create a copy. For example, deterioration of a character image is prevented and reproducibility is improved by emphasizing edges more than usual, eliminating rattling of characters, and correcting colors. Note that such a specific mark pattern can be used to provide information other than the generation copy. However, only the application to the generation copy will be described below. Therefore, the specific mark is referred to as a generation copy mark (abbreviated as a GC mark). Do). The specific mark pattern is, for example, an arrangement of a predetermined number of specific marks at equal intervals.
[0011]
The generation copy process will be described with reference to FIGS. Of course, the original document to be copied for the first time does not include a pattern composed of a generation copy mark (hereinafter also referred to as a GC mark). When such a document is read (S10) and the obtained image data is subjected to GC mark detection processing (S12), it is determined that there is no GC mark pattern (NO in S14). Therefore, normal image processing is performed on the image data (S16). Next, a process of adding a GC mark pattern to the margin of the sheet is performed (S20). Then, an image is formed on the sheet (S22).
[0012]
In the copy (first generation copy) created in this way, a pattern composed of a plurality of GC marks is formed in the margin of the paper. FIG. 2 schematically shows one example. Margins are provided on four sides of the sheet, and a plurality of GC mark patterns are formed along the sides in the margins. The GC mark has a flat shape and is formed to be horizontally long in a direction along the side of the sheet. In this example, a plurality of GC marks are arranged at equal intervals as a pattern including a plurality of GC marks. The color of the specific mark is an inconspicuous color, for example, yellow.
[0013]
Next, when the first generation copy obtained as described above is copied as a document, the document is read (S30), and the obtained image data is subjected to GC mark detection processing (S32). The mark pattern is detected (YES at D34), and it is determined that the copy is a generation copy. In that case, image processing for generation copy is performed on the image data (S38). Next, a process of adding a GC mark pattern to a blank portion of the image data is performed (S40). Then, an image is formed on the sheet (S42).
[0014]
Here, the following points should be considered for the specific mark. When a specific mark is recognized from an input image, the mark itself needs to have a certain size for pattern matching. When a specific mark is printed in a margin portion, a large margin space is required to print a large mark in consideration of ease of recognition and influence on an image. Further, when an input image is stored for recognition in pattern matching, the capacity of a line memory for storing the input image also increases because a storage capacity larger than a specific mark is required. Further, when the specific mark is large, the mark becomes more conspicuous even when an inconspicuous color is adopted. In addition, when a specific mark is printed on only one side, there is a problem that the mark position is changed depending on how the original is placed on the platen glass of the scanner, or it takes time to recognize from the scanning operation. .
[0015]
Therefore, in the present invention, the following specific marks are used as shown in FIG. (1) The shape of the specific mark is a horizontally long shape (for example, a rectangle), and is recorded horizontally long along the side of the sheet. Since the specific mark is identified by pattern matching, a certain size is required, but if it is too large, it becomes conspicuous. Since a horizontally long mark is used, it is possible to print in a small margin area while securing a fixed mark size, so that a small margin area is required. Therefore, the influence on the document image is small. In addition, since a horizontally long mark is used, even if the mark area is the same, the mark can be made less noticeable. Further, since the horizontally long mark is used, the storage capacity of the line memory in the processing circuit can be reduced, and the configuration of the processing circuit can be simplified.
[0016]
(2) Further, a plurality of specific marks are printed in the margin of the paper along the side of the paper. Since a plurality of marks are recorded, erroneous recognition can be avoided even if there is a partial defect. Since a plurality of marks are arranged along the side, printing can be performed in a small margin area. Further, as shown in FIG. 4, since the number of lines required for pattern matching is small, the capacity of the line memory in the processing circuit can be small. In one example, the interval between the specific marks is constant.
[0017]
(3) The specific mark is printed on each of the four sides of the sheet. The detection range of the specific mark is, for example, a range of the first designated number of lines at the time of scanning, and if necessary, a designated range in the main scanning direction. Therefore, as shown in FIG. 5, the mark can be recognized by performing the same processing in the same range in the sub-scanning direction regardless of how the document is placed. Therefore, the configuration of the processing circuit can be simplified, and the processing time until recognition can be shortened.
[0018]
FIG. 6 shows an overall configuration of a color copying machine that appropriately processes the above-mentioned generation copy. The configuration of this copying machine is the same as the conventional one except for the configuration of the specific document recognition circuit 24 and the GC mark related processing.
[0019]
In the scanner, the reflected light from the document read by the CCD sensor 10 is converted by an AD converter 12 into digital RGB read data. The read data is subjected to various correction processes such as shading correction, line-to-line correction, and chromatic aberration correction in the read correction unit 14. The corrected read data is processed in two paths.
[0020]
On the other hand, preprocessing for image processing is performed by the resolution conversion (enlargement / reduction) unit 16, the RGB gamma correction unit 18, the brightness / color difference separation unit 20, and the GC mark removal unit 22. The resolution conversion (enlargement / reduction) unit 16 performs a scaling process if necessary. The RGB gamma correction unit 18 performs gamma correction on the RGB data. The HVC converter 20 converts the RGB data into brightness V and color differences Cr and Cb. When the GC mark is detected from the read data, the GC mark removing unit 22 removes the GC mark from the margin.
[0021]
On the other hand, the corrected read data is processed in the specific document recognition circuit 24. In the specific document recognition circuit 24, the banknote recognition circuit 26 determines whether or not the document is a specific document such as a banknote. Further, in the specific document recognition circuit 24, a specific mark recognition chip 28 for identifying a GC mark is detachable. The specific mark recognition chip 28 includes a processing circuit 100 that performs specific mark identification processing, and a RAM 108 that is a work area. The processing circuit 100 includes a mark determination circuit 102, an element interval detection circuit 104, and an overall determination circuit 106.
[0022]
Next, image adjustment according to the characteristics of the image is performed. The sharpness correction unit 30 adjusts the sharpness of the image, and the HVC adjustment unit 32 independently adjusts brightness, saturation, and hue. Then, the color space conversion unit 34 performs conversion of the adjusted data into density data, undercolor removal / black printing processing, conversion into CMYK data, and the like. Although not shown, automatic color / monochrome document discrimination and automatic background level adjustment are also performed in parallel. When the specific document and the specific mark are not detected by the specific document recognition circuit 24, normal image adjustment is performed. When the specific mark is detected, the image adjustment for generation copy is performed. Thereafter, a specific mark (GC mark) is added to the margin by the addition processing unit 46. Although not shown, a binarization process is performed on a monochrome image.
[0023]
Next, the data is compressed by the JPEG encoding processing unit 38. The compressed data is sent to the printer unit 42 or the external device 44 via the scanner image IF 40. The printer unit 42 forms an image on a sheet based on the received data. Here, a pattern including a plurality of specific marks is formed on four sides of the sheet. The overall operation of the image processing system described above is controlled by the CPU 50. The CPU 50 is connected to a ROM 52 that stores programs and the like and a RAM 54 that is a work area.
[0024]
The specific mark recognition chip 28 recognizes a pattern composed of a plurality of specific marks arranged at equal intervals in the main scanning direction. In recognizing such specific mark patterns, it is necessary to detect specific marks arranged at predetermined intervals from image data obtained by reading a document. When recognizing a specific mark composed of a plurality of mark elements, it is difficult to accurately detect the number and arrangement of the mark elements if the general image contains colors and shapes similar to the mark elements. Note that the mark spacing here is the center spacing of marks obtained by pattern matching.
[0025]
Here, when comparing the intervals of mark elements arranged at equal intervals in one direction, generally, as shown in FIG. 7, the following procedure can be considered. Assuming that the interval between the mark elements can be a natural number multiple (for example, 1, 2, 3, or 4 times) of the specified interval, a circuit for doubling the specified interval, a circuit for multiplying the specified interval, and a quadruple. And a second comparing circuit for comparing the detected value with twice the specified interval, and a comparing circuit for comparing the detected value with twice the specified interval. A third comparison circuit and a fourth comparison circuit for comparing the detected value with four times the specified interval are provided. Then, the comparison results are output via the OR circuit. This configuration requires the number of comparison circuits to be compared. For example, if the specified interval is 31 pixels, it is necessary to compare the detected value with each of the 31 pixels, 62 pixels, 93 pixels, and 124 pixels. Also, the number of bits is required to be 8 bits or more. Therefore, it is desirable to simplify the comparison circuit. On the other hand, since the set value of the specified interval is changed according to the specifications of the machine, it is desirable to have versatility so that a plurality of values can be set. For example, it is conceivable that a request may be made to set the mark element interval to 31 pixels in the first copying machine, but to 35 pixels in the second copying machine.
[0026]
Therefore, in the present embodiment, a simple interval detection circuit shown in FIG. 8 is employed. In this circuit, the set value can be changed, and the value is multiplied by a specific conversion coefficient set from the set value input by the user to convert the value to a natural number multiple of 2 n (eg, 16). When the conversion coefficient is converted to a natural number multiple of 16 natural numbers, the lower 4 bits are always set to “0000”. Then, only a predetermined number of lower bits are compared with the detected value by the comparison circuit. Then, according to the comparison result, it is determined whether or not the interval is the specified interval. Therefore, in the configuration of the interval detection circuit, one multiplication circuit that performs multiplication with a specific conversion coefficient is used instead of a plurality of multiplication circuits, and only one comparison circuit is required. Therefore, it is possible to cope with various mark element intervals and to simplify the circuit configuration.
[0027]
Table 1 shows 15 prescribed values (element intervals) and the corresponding calculation parameters. Note that the specified value also indicates a value at 600 dpi and a value at 25 dpi in addition to the value at 200 dpi. Also, the mark element interval is indicated in mm. Further, a calculation formula for the interval w represented by 25 dpi is shown. Furthermore, the coefficient Value corresponding to each is shown. The calculation formula is w * Value / 16. Here, / 16 can be dealt with by 4-bit right shift. The lower 3 to 6 digits of the numerical value obtained by this calculation are checked.
[0028]
[Table 1]
Table 1 Mark element spacing and calculation parameters

[0029]
Specifically, the interval detection circuit shown in FIG. 9 is used. In this interval detection circuit, the interval between mark elements is detected as follows. First, an interval at 200 dpi is selected. At the time of 25 dpi conversion, the interval w at 25 dpi is multiplied by Value with reference to the element interval in Table 1 and the parameter at the time of calculation. Next, the data is shifted right by 4 bits, and division by 16 is performed. Then, the lower n bits (3, 4, 5, or 6 bits) are inspected.
[0030]
More specifically, when the CPU 50 sets the parameter N in the processing circuit 100, the set value holding unit 112 holds the set value of the number of pixels at 25 dpi in the element interval calculation circuit 104 correspondingly. (For example, when N = 9 in Table 1, a value of 40 is selected.) Next, the coefficient selection unit 116 refers to the table 114 and selects a coefficient Value. (For example, when N = 9 in the table, a value of 13 is selected.) On the other hand, the X coordinate counter 118 is a counter in the X direction, counts a reference signal after initialization, and counts the count result. Output at 200 dpi. The difference calculation unit 120 calculates the difference between the X coordinate PreX of the previously detected element and the counter 118, and calculates the element interval w at 200 dpi. The multiplier 122 multiplies the coefficient Value by the element interval w. At the same time, a total of 7 bits of 3 bits for resolution conversion and 4 bits for division by 16 are shifted right. (Thus, multiplier 122 outputs w * Value / 16.) Comparing section 124 sets a predetermined number of lower bits (for example, lower 4 bits when N = 9 in the table) of the multiplication result to 0 (or ±). Compare 1) or not. Here, ± 1 indicates an allowable range. When the first mark element is detected, or when the distance from the previous element instead of the first mark element is a specified value, the result is sent to the detection circuit including the detection number counting section 155 and the holding section 126. The detection number counting unit 155 increases the detection number by one. In addition, when the comparing unit 124 performs element detection, the holding unit 126 holds the X coordinate as the immediately preceding detected coordinate PreX. The detected coordinates of the holding unit 126 are sent to the difference calculation unit 120.
[0031]
In the mark determination circuit 102 in the processing circuit 100, the X detection range and the Y detection range input from the CPU 50 are stored in the setting holding unit 151. The determination of the specific mark proceeds by receiving an image signal when the sub-scanning effective area signal and the main scanning effective area signal are output. After the initialization, the Y coordinate counter 150 counts the Y coordinate when the sub-scanning effective area signal is output, and the X coordinate counter 118 counts the X coordinate when the main scanning effective area signal is output. Count. The effective area signal generation circuit 152 generates an effective area signal based on the X detection range and the Y detection range and the main scanning effective area signal. When the effective area signal is output, the element determination circuit 153 receives the image data, determines a mark element by pattern matching, and outputs a determination result.
[0032]
In the mark determination circuit 102 in the processing circuit 100, the count-up number determination unit 154 includes a mark element determination result from the mark determination circuit 102, an interval determination result from the element interval calculation circuit 104, and a PreFlag from the holding unit 156. Thus, the validity / invalidity of the determined mark element is determined. The detection determination unit 157 sets a flag PreFlag indicating that a mark element candidate has been detected from the mark element determination result, the interval determination result, and the Preflag held in the holding unit 156. The detection number counting unit 155 outputs the mark element detection number nCount based on the mark element determination result. The processing contents of the count-up number determination unit 154 and the detection determination unit 157 will be described later with reference to FIG.
[0033]
Next, processing in the comparison unit 124 in the processing circuit 100 will be described with reference to Table 1. (1) If the interval at 200 dpi is 64 dots or 96 dots, the lower 3 bits are inspected. If (w & 0x7) is 0x1, 0x0 or 0x7, that is, if the lower 3 bits are 001, 000 or 111, it is OK. (2) If the interval at 200 dpi is from 128 dots to 224 dots, the lower 4 bits are inspected. If (w & 0xf) is 0x1, 0x0 or 0xf, that is, if the lower 4 bits are 0001, 0000 or 1111, it is OK. (3) If the interval at 200 dpi is from 256 dots to 480 dots, the lower 5 bits are inspected. If (w & 0x1f) is 0x1, 0x0 or 0x1f, that is, if the lower 5 bits are 00001, 00000 or 11111, it is OK. (4) If the interval at 200 dpi is 512 dots, the lower 6 bits are inspected. If (w & 0x3f) is 0x1, 0x0 or 0x3f, that is, if the lower 6 bits are 000001, 000000 or 111111, it is OK.
[0034]
Note that the parameter N may be automatically set according to the model of the device on which the image processing device is mounted. FIG. 10 is a flowchart of the setting value automatic setting in that case. When the specific mark recognition chip 28 is mounted on the image processing apparatus (YES in S60), the model is identified. If the apparatus is the model A (YES in S62), N indicating the parameter (Table 1) is set to 1. (S64). If the device is model B (YES in S66), N indicating the parameter is set to 2 (S68). Hereinafter, similarly, N is set according to the model.
[0035]
Hereinafter, the processing procedure in the specific mark recognition chip 28 will be described. FIG. 11 shows a flow of a process of recognizing a pattern including a plurality of specific marks. First, R, G, and B image data (each 8 bits) are input to the element determination circuit 153 (S100). Next, the color of the GC mark is extracted from the input image data (S102). The element determination circuit 153 determines whether or not the input R, G, B image densities are within a predetermined reference density range, and performs binarization. As a result, binary data is obtained. Next, noise is removed from the binary image data (S104). Here, an isolated point composed of one pixel is removed. Next, a specific mark element shape is detected from the binary data thus obtained by using a mark detection parameter for pattern matching (S106). Here, for example, a mark element shape is extracted using an element filter of 11 × 11 pixels. Next, the detection determination unit 157 checks whether or not the detected mark element is at a predetermined interval (S108). Here, if the difference between the previously detected mark element and the x coordinate position PreX is a natural number multiple of the specified mark element interval, it is determined that the mark element is a mark element. Next, the detected number counting unit 155 calculates the number of mark elements at a predetermined interval (S110). Then, the number of mark elements is totaled, it is determined whether or not the number is a specified number, and the result is output (S112). Here, if the number of mark elements is a specified number, it is determined that the copy is a generation copy.
[0036]
FIG. 12 shows more detailed processing of the mark interval inspection (FIG. 11, S108) and the mark number count (FIG. 11, S110) in the specific mark recognition chip 28. Here, the detection of the specific mark from the image data is performed within the range of the designated number of lines from the edge of the document. As described above, it is assumed that the specific marks are arranged at predetermined intervals. The input image data is sequentially scanned, and the element determination circuit 153 detects the pattern of the specific mark. The coordinate position of the binary data is represented by (X, Y). First, as preprocessing, the CPU 50 sets the X detection range and the Y detection range in the set value holding circuit 151. Further, the mark element prescribed interval is set in the holding circuit 112. In the case of an effective area, the effective area signal generation circuit 152 outputs an effective area signal. When the sub-scanning effective area signal becomes H level, the number-of-detection-mark elements nCount is initialized to 0 in the detection-number counting unit 155, and the value of the Y coordinate is initialized to 0 in the Y-coordinate counter 150 (S200). Next, when the main scanning effective area signal becomes H level, the value of the X coordinate is initialized to 0 in the X coordinate counter 118 (S202). Next, the element determination circuit 153 detects a mark element candidate by pattern matching using a mark element filter of 11 × 11 pixels (S204). When a mark element candidate is detected, the detection determination unit 157 determines whether or not the mark element is the first mark element (S206). If the mark element is the first mark element, the detected number counting section 155 increments the number nCount of detected mark elements, and the detection determining section 157 sets a flag PreFlag indicating that a mark element candidate has been detected (S208). Further, the X coordinate of the center of the detected mark element is set to x1, and the current value of X is set to the previously detected mark element position PreX of the coordinate holding unit 126 (S222). If the mark element candidate is not the first mark element (NO in S206), the X coordinate of the mark element is set to x2. Next, it is determined whether or not the distance (absolute value of the difference between x2 and x1) between the mark element and the immediately preceding detected mark element position PreX is a natural number multiple of the specified interval W by the lower-order bit in the comparing unit 124 (S210). Here, as described above, a multiplication value using the coefficient selected from the table 114 is used. If it is a natural number multiple of the specified interval W (that is, if abs (x2−x1) = nW ± 1), the number of detection mark elements nCount is incremented by the detection number counting unit 155 (S212). Here, ± 1 indicates an allowable range. Count-up number determining section 154 outputs a signal to detected number counting section 155 when counting should be performed. If the flag PreFlag output from the detection determination unit 157 is 0 (YES in S214), the detection number counting unit 155 increments the number nCount of detection mark elements (S216), and it was previously determined that it was not a mark element candidate. Mark element candidates are also treated as detected mark elements. Then, the holding unit 156 sets the flag PreFlag to 1 (S218). Further, the current value of the X coordinate is set to the previous detection mark element position PreX in the element detection coordinate holding unit 126 (S222). If it is not the designated interval W (NO in S210), the holding unit 156 sets the flag PreFlag to 0 (S220). Further, the current value of X is set to the previously detected mark element position PreX in the holding unit 126 (S222).
[0037]
Next, the X coordinate counter 118 increments X and moves the position in the main scanning direction (S224). If X is within the X detection range (NO in S226), the process returns to step S204 to continue mark element detection. .
[0038]
When X is no longer within the X detection range (YES in S226), the Y coordinate counter 150 increments Y and moves the position in the sub-scanning direction (S228). If Y is within the Y detection range (NO in S230), the process returns to step S202 to continue the mark element detection. When Y is no longer within the Y detection range (YES in S230), the process ends. The value of nCount at this time is the number of detected marks.
[0039]
FIG. 13 shows an example of the mark number counting operation. In this example, mark element candidates indicated by rectangles are detected in the order shown in the figure. When the first mark element candidate is detected, the detected element number nCount becomes 1, and the flag PreFlag is set to 1. Next, the second mark element candidate is detected, but is not present at the position of the specified interval, so that it is determined that it is not a mark element. Therefore, the flag PreFlag is set to 0. Next, although the third mark element candidate is detected but does not exist at the position of the specified interval, it is determined that the element is not an element, and the flag PreFlag is set to 0. When the fourth mark element candidate is detected, the mark element is present at the position of the specified interval, so the detected element number nCount becomes 2, and since the previous element candidate is determined not to be at the specified interval, it is valid. Is determined to be an element candidate, and the number nCount of detected elements further increases to 3. Then, the flag PreFlag is set to 1.
[0040]
【The invention's effect】
In the detection of a pattern composed of a plurality of marks, it is determined whether or not the mark interval is a set value or a natural number multiple thereof, so that only one comparing means is required and the configuration of the mark interval detection can be greatly simplified. .
Since the data is converted to a natural number times 2 to the power of n, the number of bits to be compared by the comparing means can be reduced.
By providing the setting means for setting the set value, the set value can be set, for example, for each model.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a first generation copy process. FIG. 2 is a diagram showing an example of a generation copy. FIG. 3 is a flowchart showing a second generation copy process. FIG. 4 is a diagram showing lines necessary for recognition. FIG. 5 is a diagram showing a detection process in a case where a document is placed differently. FIG. 6 is a block diagram showing an overall configuration of a color copying machine. FIG. 7 compares intervals of mark elements arranged at equal intervals in the main scanning direction. FIG. 8 is a diagram showing a concept of a circuit for comparing intervals of mark elements arranged at equal intervals in the main scanning direction. FIG. 9 is a circuit diagram of a mark element interval detecting circuit. FIG. 10 is an image processing. Flowchart of automatic setting of setting values according to the model in which the device is mounted [Fig. 11] Flowchart of specific mark recognition in specific mark recognition chip [Fig. [EXPLANATION OF SYMBOLS] Figure for explanation bets 13 mark number counting
Reference Signs List 10 CCD sensor, 22 GC mark removal unit, 24 specific document recognition circuit, 28 specific mark recognition chip, 30 sharpness correction unit, 32 HVC adjustment unit, 34 color space conversion unit, 36 additional processing unit, 50 CPU, 100 processing circuit, 102 Mark judgment circuit 102, 104 Element interval calculation circuit, 106 comprehensive judgment circuit, 112 set value holding section, 116 coefficient selection section, 118 X coordinate counter, 120 difference calculation section, 122 multiplier, 124 comparison section, 126 holding section, 153 A generation mark element determination unit, 154 count-up number determination unit, 155 detection number count unit, 157 detection determination unit.

Claims (5)

Mark detection means for sequentially scanning input image data to detect a specific mark;
Interval detecting means for detecting an interval between the plurality of detected specific marks,
Conversion means for converting a preset value into a natural number times 2 to the power of n;
An image processing apparatus comprising: a comparison unit configured to compare the interval detected by the interval detection unit with a set value converted by the conversion unit and determine whether the interval is a designated value or a natural number multiple thereof. 2. The image processing apparatus according to claim 1, wherein the conversion unit multiplies the set value by a coefficient corresponding to the set value to convert the set value to a natural number times 2 n. The image processing apparatus according to claim 1, further comprising a setting unit configured to set the set value. 4. The image processing apparatus according to claim 1, further comprising an image processing unit that performs predetermined image processing on the input image data when the mark is detected. The image processing apparatus according to claim 4, wherein, when the mark is detected, the image processing unit recognizes that the document is a specific document, and performs image processing suitable for a generation copy.

Images