JPH0795397A - Original reader - Google Patents
Original readerInfo
- Publication number
- JPH0795397A JPH0795397A JP5236692A JP23669293A JPH0795397A JP H0795397 A JPH0795397 A JP H0795397A JP 5236692 A JP5236692 A JP 5236692A JP 23669293 A JP23669293 A JP 23669293A JP H0795397 A JPH0795397 A JP H0795397A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- character
- signal
- high density
- image area
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は原稿読取装置に係り、特
に文字再現性を向上可能な像域識別回路を採用した原稿
読取装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading device, and more particularly to a document reading device which employs an image area identifying circuit capable of improving character reproducibility.
【０００２】[0002]
【従来の技術】従来の原稿読取装置にあっては、読取光
学系で読取った原稿の画像信号に対して、原稿中の文字
再現性を良くするためにエッジ抽出処理を行うと共に、
抽出したエッジ信号に基ていてミクロ識別処理を施して
得られる情報により、原稿中の文字領域と文字以外の階
調領域（例えば写真部分や網点部分）との処理を切換え
ていた。2. Description of the Related Art In a conventional document reading apparatus, an edge extraction process is performed on an image signal of a document read by a reading optical system in order to improve the reproducibility of characters in the document.
Based on the information obtained by performing the micro-identification processing based on the extracted edge signal, the processing is switched between the character area in the document and the gradation area other than the character (for example, a photograph part or a halftone dot part).
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、このよ
うな従来の技術では、画像のエッジ部分の強弱により、
すなわちエッジ強であれば文字処理とし、且つエッジ弱
であれば階調処理を行うように処理形態を切換えている
だけであるので、次のような欠点を有していた。However, in such a conventional technique, due to the strength of the edge portion of the image,
That is, since the processing mode is simply switched so that the character processing is performed when the edge is strong and the gradation processing is performed when the edge is weak, the following drawbacks occur.
【０００４】図５（ａ）に示すように高濃度太文字に対
しては、エッジのみが強調されて太文字の中が文字と判
定されずに擬似階調処理となってしまうので、白抜け状
態を生じてしまう。As shown in FIG. 5A, for a high density thick character, only the edges are emphasized, and the inside of the bold character is not judged to be a character and the pseudo gradation process is performed. It causes a state.
【０００５】さらに、高濃度太文字の中をベタ黒にし文
字再現性を向上させようとすると、高濃度背面も黒く潰
れるため階調が維持できなかった。また、図５（ｂ）に
示すように、例えば５ポイント程度の小文字に対して
は、エッジ信号の小さい細かな小文字の中央部が文字と
判定されないで階調処理となってしまうために、解像度
を保つことが困難で文字再現性に劣化を生じてしまう。Further, when trying to improve the character reproducibility by making the high density thick characters solid black, it was not possible to maintain the gradation because the back surface of the high density was also blackened. Further, as shown in FIG. 5B, for a small letter of about 5 points, for example, the central portion of a small small letter with a small edge signal is not determined to be a character, and gradation processing is performed. Is difficult to maintain, and the character reproducibility deteriorates.
【０００６】すなわち、従来の技術では、文字再現性
（解像度）が悪いと共に、再生画像中に余分な白黒変化
点が発生するために例えば電子ファイルシステム、ＦＡ
Ｘ等の画像圧縮を必要とする場合に圧縮効率が低下して
しまうという問題を有していた。That is, in the prior art, the character reproducibility (resolution) is poor and an extra black-and-white change point occurs in the reproduced image.
There is a problem that the compression efficiency decreases when image compression such as X is required.
【０００７】そこで、本発明は以上のような点に鑑みて
なされたもので、高濃度太文字の中と小文字の中央部を
文字処理し、高濃度背面は階調処理とすることにより、
従来の像域識別の問題点を解消して高画質化を実現する
と共に、文字再現性を向上可能な像域識別回路を採用し
た原稿読取装置を提供することを目的としている。Therefore, the present invention has been made in view of the above points, and character processing is performed on the middle part of middle and lower case of high-density thick characters, and gradation processing is performed on the high-density back surface.
An object of the present invention is to provide a document reading apparatus that solves the problems of conventional image area identification and realizes high image quality, and that employs an image area identification circuit that can improve character reproducibility.
【０００８】[0008]
【課題を解決するための手段】上記課題を解決するため
に、本発明によると、被読取用原稿を光学的に走査して
画像信号を出力する読取光学系と、前記読取光学系から
の画像信号におけるエッジ信号および高濃度信号を抽出
する抽出手段と、前記抽出手によって抽出されたエッジ
信号および高濃度信号に基いて像域識別を行うもので、
前記エッジ信号における主走査および副走査方向共に所
定距離のエッジに挟まれた領域中の高濃度領域を文字領
域と識別すると共に、それ以外の領域を非文字領域と識
別する像域識別手段と、前記抽出手段からの画像信号に
対して前記像域識別手段からの文字領域の識別信号に応
じて文字処理を選択すると共に、非文字領域の識別信号
に応じて階調処理を選択する選択手段とを具備すること
を特徴とする原稿読取装置が提供される。In order to solve the above-mentioned problems, according to the present invention, a reading optical system which optically scans an original to be read and outputs an image signal, and an image from the reading optical system. Extraction means for extracting an edge signal and a high density signal in the signal, and for performing image area discrimination based on the edge signal and the high density signal extracted by the extraction hand,
Image area identifying means for identifying a high-density area in an area sandwiched by edges having a predetermined distance in both the main scanning direction and the sub-scanning direction in the edge signal as a character area and identifying the other areas as non-character areas. Selecting means for selecting character processing for the image signal from the extracting means in accordance with the identification signal of the character area from the image area identifying means, and selecting gradation processing in accordance with the identification signal for the non-character area; There is provided a document reading device comprising:
【０００９】[0009]
【作用】上記解決手段によると、像域識別手段は画像デ
ータのエッジ情報を抽出し、主走査、副走査共に所定距
離エッジに挾まれた領域中の高濃度領域を文字領域とし
文字処理を行い、それ以外の領域は階調処理を行う。According to the above-mentioned solution means, the image area identification means extracts the edge information of the image data and performs the character processing by using the high density area in the area sandwiched by the predetermined distance edge as the character area in both the main scanning and the sub scanning. The gradation processing is performed in the other areas.
【００１０】[0010]
【実施例】以下図面を参照して本発明の実施例につき詳
細に説明する。図１は本発明による原稿読取装置の概略
構成を示すブロック図である。すなわち、図１において
本体１０中に設けられた読取光学系１１は原稿台（ガラ
ス）１２上に載置された原稿１３を光学的に走査して画
像信号を出力する。Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a document reading apparatus according to the present invention. That is, in FIG. 1, the reading optical system 11 provided in the main body 10 optically scans a document 13 placed on a document table (glass) 12 and outputs an image signal.
【００１１】この画像信号はＣＰＵ、メカニカルコント
ロール回路、画像処理回路（像域識別回路等を含む）か
らなる制御回路１４で所定の処理が施された後、インタ
フェース１５を介して例えば電子ファイル装置のコント
ローラやプリンタコントローラ（ＰＣ）等でなるホスト
機器１６に供給される。This image signal is subjected to a predetermined processing by a control circuit 14 including a CPU, a mechanical control circuit, and an image processing circuit (including an image area identification circuit), and then, via an interface 15, for example, an electronic file device. It is supplied to the host device 16 such as a controller or a printer controller (PC).
【００１２】図２は以上における制御回路１４の特に画
像処理回路部を示している。すなわち、図１の読取光学
系１１で光電変換により得られた画像信号はＡ／Ｄ変換
器２１でディジタル信号に変換された後、平滑化回路２
２および高周波成分補正のための回路（以下ＭＴＦ補正
回路という）２３を介してエッジ成分が例えばラプラシ
アンエッジ信号として抽出されると共に、高濃度信号成
分が抽出される。FIG. 2 shows particularly the image processing circuit section of the control circuit 14 described above. That is, the image signal obtained by photoelectric conversion in the reading optical system 11 in FIG. 1 is converted into a digital signal by the A / D converter 21, and then the smoothing circuit 2
An edge component is extracted as a Laplacian edge signal, for example, and a high density signal component is extracted via a circuit 2 for correcting high frequency components (hereinafter referred to as an MTF correction circuit) 23.
【００１３】前記ＭＴＦ補正回路２３で抽出されたエッ
ジ信号および高濃度信号は像域識別回路２４に供給され
る。図３は図２の像域識別回路２４の具体例を示してい
る。The edge signal and the high density signal extracted by the MTF correction circuit 23 are supplied to the image area discrimination circuit 24. FIG. 3 shows a specific example of the image area discrimination circuit 24 of FIG.
【００１４】すなわち、図３において、エッジ信号は２
値化回路３１によって所定のしきい値で２値化されるこ
とにより、微弱なエッジ成分（例えばノイズ的エッジ）
が除去される。That is, in FIG. 3, the edge signal is 2
A weak edge component (for example, a noise-like edge) is generated by binarizing the binarization circuit 31 with a predetermined threshold value.
Are removed.
【００１５】前記２値化回路３１で２値化されたエッジ
信号はミクロ識別回路３２に供給される。このミクロ識
別回路３２は２値化エッジ信号を主走査および副走査方
向共に例えば４×４画素で局所展開して所定のパターン
テーブルと照合することにより、文字領域と写真／網点
領域に分別するようなミクロ識別を施す。The edge signal binarized by the binarization circuit 31 is supplied to the micro discrimination circuit 32. The micro discrimination circuit 32 locally develops the binarized edge signal in, for example, 4 × 4 pixels in both the main scanning direction and the sub-scanning direction and collates it with a predetermined pattern table to classify it into a character area and a photograph / halftone dot area. Such micro identification is performed.
【００１６】前記ミクロ識別回路３２でミクロ識別され
たエッジ信号はエッジ間補間回路３３に供給される。こ
のエッジ間補間回路３３は所定距離間内にある２つのエ
ッジに挟まれた領域（図４（ａ），（ｂ）の補間距離ａ
参照）を文字領域候補として補間する。The edge signal micro-identified by the micro-identification circuit 32 is supplied to the inter-edge interpolation circuit 33. The inter-edge interpolating circuit 33 is a region between two edges within a predetermined distance (interpolation distance a in FIGS. 4A and 4B).
(See) is interpolated as a character area candidate.
【００１７】前記エッジ間補間回路３３からのエッジ間
補間データは、遅延回路３４を介して供給記される前記
高濃度信号とのアンドがアンドゲート３４でとられるこ
とにより、アンドが成立したときにアンドゲート３４か
ら文字領域を示す信号が像域識別回路２４の識別信号と
して出力される。The inter-edge interpolation data from the inter-edge interpolation circuit 33 is ANDed with the high density signal supplied through the delay circuit 34 by the AND gate 34, so that when AND is established. A signal indicating the character area is output from the AND gate 34 as an identification signal of the image area identification circuit 24.
【００１８】このアンドゲート３４においてアンドが成
立しないときには文字領域以外を示す信号が像域識別回
路２４の識別信号として出力される。ここで、図２に戻
ると、前記ＭＴＦ補正回路２３の出力は階調処理回路２
５および文字処理回路２６とに分離される。When AND is not established in the AND gate 34, a signal other than the character area is output as an identification signal of the image area identification circuit 24. Now, returning to FIG. 2, the output of the MTF correction circuit 23 is the gradation processing circuit 2.
5 and the character processing circuit 26.
【００１９】これら階調処理回路２５および文字処理回
路２６の出力は切換回路２７の第１および第２固定接点
２７１，２７２に導出される。ここで、切換回路２７の
可動接点は像域識別回路２４の出力として図３のアンド
ゲート３４からの識別信号で制御される。The outputs of the gradation processing circuit 25 and the character processing circuit 26 are led to the first and second fixed contacts 271, 272 of the switching circuit 27. Here, the movable contact of the switching circuit 27 is controlled by the identification signal from the AND gate 34 of FIG. 3 as the output of the image area identification circuit 24.
【００２０】すなわち、像域識別回路２４において、文
字領域と判定されたとき、切換回路２７は文字処理回路
２６の出力を選択し、且つ文字以外の領域と判定された
ときには階調処理回路２５の出力を選択して、各出力を
インタフェース回路１５を介してホスト機器１６（図
１）に供給する。That is, when the image area discrimination circuit 24 determines that the area is a character area, the switching circuit 27 selects the output of the character processing circuit 26, and when it is determined that the area is other than the character area, the gradation processing circuit 25 operates. The output is selected and each output is supplied to the host device 16 (FIG. 1) via the interface circuit 15.
【００２１】図４は以上のような本発明による原稿読取
装置の読取り例を高濃度太文字（ａ）と高濃度小文字
（ｂ）とに分けて示している。すなわち、図４（ａ），
（ｂ）においてミクロ識別後エッジ信号に対してエッジ
間補間を行うことにより、白抜けや中央部に階調処理を
含まない原稿文字に対応した所定の解像度を有すると共
に良好な文字再現性を有した文字領域出力信号（出力画
像）が得られるようになる。FIG. 4 shows an example of reading by the document reading apparatus according to the present invention, which is divided into high-density thick letters (a) and high-density lower case letters (b). That is, in FIG.
By performing edge-to-edge interpolation on the edge signal after micro-identification in (b), it has a predetermined resolution corresponding to a document character that does not include white spots or gradation processing in the central portion, and also has good character reproducibility. The character area output signal (output image) can be obtained.
【００２２】これに対し、従来の技術ではミクロ識別後
エッジ信号に対して本発明のようなエッジ間補間を行う
ことなく、直ちに文字処理および階調処理とに切換えて
いるために、図５（ａ），（ｂ）に示すような解像度が
悪く文字再現性の悪に不所望な出力画像になってしま
う。On the other hand, in the prior art, the character processing and the gradation processing are immediately switched to the edge signal after micro-discrimination without performing the edge-to-edge interpolation as in the present invention as shown in FIG. As shown in a) and (b), an undesired output image is obtained due to poor resolution and poor character reproducibility.
【００２３】[0023]
【発明の効果】従って、以上詳述したように本発明によ
れば、高濃度太文字の中と小文字の中央部を文字処理
し、高濃度背面は階調処理とすることにより、従来の像
域識別の問題点を解消して高画質化を実現すると共に、
文字再現性を向上可能な像域識別回路を採用した原稿読
取装置を提供することができる。Therefore, according to the present invention as described above in detail, by performing the character processing on the middle portion of the middle and lower case of the high density thick character and the gradation processing on the high density back surface, the conventional image can be obtained. While solving the problem of area identification and realizing high image quality,
It is possible to provide a document reading device that employs an image area identification circuit that can improve character reproducibility.
【図１】本発明による装置構成の概要を示すブロック
図。FIG. 1 is a block diagram showing an outline of a device configuration according to the present invention.
【図２】本発明に用いる画像処理回路の具体例を示すブ
ロック図。FIG. 2 is a block diagram showing a specific example of an image processing circuit used in the present invention.
【図３】本発明に用いる像域識別回路の具体例を示すブ
ロック図。FIG. 3 is a block diagram showing a specific example of an image area identification circuit used in the present invention.
【図４】本発明による像域識別の具体例を示す図。FIG. 4 is a diagram showing a specific example of image area identification according to the present invention.
【図５】従来の技術による文字処理結果を示す図。FIG. 5 is a diagram showing a character processing result according to a conventional technique.
１０…本体、 １１…読取光学系、 １２…原稿台（ガラス）、 １３…原稿、 １４…制御回路、 １５…インタフェース、 １６…ホスト機器、 ２１…Ａ／Ｄ変換器、 ２２…平滑化回路、 ２３…ＭＴＦ補正回路、 ２４…像域識別回路、 ２５…階調処理回路、 ２６…文字処理回路、 ３１…２値化回路、 ３２…ミクロ識別回路、 ３３…エッジ間補間回路、 ３４…遅延回路。 DESCRIPTION OF SYMBOLS 10 ... Main body, 11 ... Reading optical system, 12 ... Manuscript stand (glass), 13 ... Manuscript, 14 ... Control circuit, 15 ... Interface, 16 ... Host device, 21 ... A / D converter, 22 ... Smoothing circuit, 23 ... MTF correction circuit, 24 ... Image area identification circuit, 25 ... Gradation processing circuit, 26 ... Character processing circuit, 31 ... Binarization circuit, 32 ... Micro identification circuit, 33 ... Edge interpolation circuit, 34 ... Delay circuit .
Claims (1)
号を出力する読取光学系と、 前記読取光学系からの画像信号におけるエッジ信号およ
び高濃度信号を抽出する抽出手段と、 前記抽出手によって抽出されたエッジ信号および高濃度
信号に基いて像域識別を行うもので、前記エッジ信号に
おける主走査および副走査方向共に所定距離のエッジに
挟まれた領域中の高濃度領域を文字領域と識別すると共
に、それ以外の領域を非文字領域と識別する像域識別手
段と、 前記抽出手段からの画像信号に対して前記像域識別手段
からの文字領域の識別信号に応じて文字処理を選択する
と共に、非文字領域の識別信号に応じて階調処理を選択
する選択手段とを具備することを特徴とする原稿読取装
置。1. A reading optical system that optically scans a document to be read and outputs an image signal, an extraction unit that extracts an edge signal and a high-density signal in the image signal from the reading optical system, and the extraction. The image area is identified based on the edge signal and the high density signal extracted by hand, and the high density area in the area sandwiched by the edges of a predetermined distance in the main scanning direction and the sub scanning direction in the edge signal is a character area. Image area identifying means for identifying other areas as non-character areas, and character processing is performed on the image signal from the extracting means in accordance with the character area identifying signal from the image area identifying means. An original reading apparatus comprising: a selecting unit that selects a gradation process according to an identification signal of a non-character region.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5236692A JPH0795397A (en) | 1993-09-22 | 1993-09-22 | Original reader |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5236692A JPH0795397A (en) | 1993-09-22 | 1993-09-22 | Original reader |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0795397A true JPH0795397A (en) | 1995-04-07 |
Family
ID=17004362
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5236692A Pending JPH0795397A (en) | 1993-09-22 | 1993-09-22 | Original reader |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0795397A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6681047B1 (en) | 1999-05-31 | 2004-01-20 | Ricoh Co., Ltd. | Method and system for determining character edges based upon edges pair and image characteristics of pixels between the edge pair |
| US6965695B2 (en) | 2000-03-23 | 2005-11-15 | Ricoh Company, Ltd. | Method and system for processing character edge area data |
| JP2015148986A (en) * | 2014-02-07 | 2015-08-20 | 富士通株式会社 | Information processing apparatus, blur level calculation method, and program |
-
1993
- 1993-09-22 JP JP5236692A patent/JPH0795397A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6681047B1 (en) | 1999-05-31 | 2004-01-20 | Ricoh Co., Ltd. | Method and system for determining character edges based upon edges pair and image characteristics of pixels between the edge pair |
| US6965695B2 (en) | 2000-03-23 | 2005-11-15 | Ricoh Company, Ltd. | Method and system for processing character edge area data |
| JP2015148986A (en) * | 2014-02-07 | 2015-08-20 | 富士通株式会社 | Information processing apparatus, blur level calculation method, and program |
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