JPS62185467A - Picture signal binary-coding device - Google Patents

Picture signal binary-coding device

Info

Publication number
JPS62185467A
JPS62185467A JP61027092A JP2709286A JPS62185467A JP S62185467 A JPS62185467 A JP S62185467A JP 61027092 A JP61027092 A JP 61027092A JP 2709286 A JP2709286 A JP 2709286A JP S62185467 A JPS62185467 A JP S62185467A
Authority
JP
Japan
Prior art keywords
density
value
binary
point
data
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.)
Granted
Application number
JP61027092A
Other languages
Japanese (ja)
Other versions
JPH0551225B2 (en
Inventor
Yuji Katsuta
祐司 勝田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Sharp Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sharp Corp filed Critical Sharp Corp
Priority to JP61027092A priority Critical patent/JPS62185467A/en
Publication of JPS62185467A publication Critical patent/JPS62185467A/en
Publication of JPH0551225B2 publication Critical patent/JPH0551225B2/ja
Granted legal-status Critical Current

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  • Image Input (AREA)
  • Image Processing (AREA)
  • Facsimile Image Signal Circuits (AREA)

Abstract

PURPOSE:To apply binary-coding with fidelity for both two gradation and multi- gradation by outputting a binary-coding data forcibly when a density at a point to be binary-coded differs largely from the surrounding average density and outputting a binary-coding data in response to the average density when they are close to each other. CONSTITUTION:An average density calculation circuit 4 calculates an average density at a point within a range from, e.g., 15X15 points of digital data around a point to be binary-coded. In case a picture of binary gradation where the density of a point to be binary-coded and the surrounding average density differ largely is used, '1' or '0' is outputted forcibly at a terminal 13. In case the density of a point to be binary-coded is smaller than the surrounding mean density added by a prescribed value and larger than the subtraction of a prescribed value from the surrounding average density, an output of a comparator '7' is '0' and an output of a comparator '8' is '1'. A data binary-coding the mean density outputted from a comparator 10 by the dither method is outputted. That is, a binary-coding data in response to the surrounding average density is outputted.

Description

【発明の詳細な説明】 〈産業上の利用分野〉 本発明はアナログ画像信号を2値化する画像信号2値化
装置に関する。
DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an image signal binarization device that binarizes an analog image signal.

〈従来の技術〉 写真のような多階調の原稿を画像信号に変換する方法と
してディザ法がある。また、文字のような2階間原稿は
2階調の画像信号に変換する。しかし、実際の原稿には
、写真のように多階調の画像信号に変換するほうがよい
ものと、文字のように2階調の画像信号に変換するほう
がよいものが混在する場合がある。この場合、ディザ法
を用いると文字が読めなくなるかあるいは読みにくくな
ることがあり、2階調の画像信号に変換すると多階調の
部分がつぶれてしまうという欠点があった。
<Prior Art> A dither method is a method for converting a multi-tone original such as a photograph into an image signal. Further, a two-level original such as text is converted into a two-tone image signal. However, in actual documents, there may be a mixture of some documents, such as photographs, which are better converted into multi-tone image signals, and some documents, such as letters, which are better converted into two-tone image signals. In this case, when the dither method is used, the characters may become unreadable or difficult to read, and when converted to a two-tone image signal, the multi-tone portions are lost.

〈発明の目的〉 本発明は上記事情に鑑みてなされたものであり、同−原
稿内の多階調部分と2階調部分をともに忠実に画像信号
に変換できるようにした画像信号2値化装置の提供を目
的とする。
<Object of the Invention> The present invention has been made in view of the above-mentioned circumstances. The purpose is to provide equipment.

〈実施例〉 以下、本発明の画像信号2値化装置の−実格例を図面に
もとづいて説明する。
<Embodiment> Hereinafter, an actual example of the image signal binarization device of the present invention will be described based on the drawings.

ADコンバータ1は、原稿画像の一定範囲のアナログビ
デオ信号を8ビツトのディジタルデータに変換する。こ
の変換されたディジタルデータの値が大きいほど、原稿
画像の濃度は大である。メモリ2は、ADコンバータ1
からのディジタルデータを記憶する。D形フリップフロ
ップ3は、原稿画像の2値化する点のディジタルデータ
をラッチする。
The AD converter 1 converts an analog video signal of a certain range of an original image into 8-bit digital data. The greater the value of the converted digital data, the greater the density of the original image. Memory 2 is AD converter 1
Store digital data from. The D-type flip-flop 3 latches digital data at points to be binarized in the original image.

平均濃度演算回路4は、2値化する点を中心にして15
X15点のディジタルデータからこの範囲にある点の濃
度の平均値を算出する。加算用PROM5は、平均濃度
演算回路4から濃度の平均値がアドレスデータとして与
えられると、この平均値に所定の値を加算した値を出力
する。減算用PROM6は、平均濃度演算回路4から濃
度の平均値がアドレスデータとして与えられると、この
平均値から所定の値を減算した値を出力する。
The average density calculation circuit 4 calculates 15 points centered on the point to be binarized.
The average value of the density of points within this range is calculated from the digital data of X15 points. When the addition PROM 5 receives the average density value as address data from the average density calculation circuit 4, it outputs a value obtained by adding a predetermined value to this average value. When the subtraction PROM 6 receives the average density value as address data from the average density calculation circuit 4, it outputs a value obtained by subtracting a predetermined value from this average value.

コンパレータ7は、D形フリップフロップ3が保持する
データと加算用FROM5が出力したデータとを比較し
、D形フリップフロップ3のデータが加算用PROM5
のデータより大であると“1”を出力する。コンパレー
タ8は、D形フリップフロップ3のデータと減算用FR
OM6が出力したデータとを比較し、D形フリップフロ
ップ3のデータが減算用PROM6のデータより小であ
るとuO″を出力し、D形フリップフロップ3のデータ
が減算用FROM6のデータより大であると“1”を出
力する。
The comparator 7 compares the data held by the D-type flip-flop 3 with the data output from the addition FROM 5, and the data in the D-type flip-flop 3 is compared with the data held in the addition PROM 5.
If the data is greater than the data, "1" is output. The comparator 8 connects the data of the D-type flip-flop 3 with the FR for subtraction.
It compares the data outputted by OM6 and outputs uO'' if the data of D-type flip-flop 3 is smaller than the data of PROM6 for subtraction, and if the data of D-type flip-flop 3 is larger than the data of PROM6 for subtraction. If it exists, it outputs “1”.

ディザ用PROM9は、与えられたアドレスデータの2
ビツトはディザタイプの選択に用い、残り6ビツトで8
×8デイザパターンのうちの1点の選択を行なう。コン
パレータ10はディザ用PROM9の出力データと平均
濃度演算回路4からの濃度の平均値を比較し、平均濃度
をディザ法により2値化したデータを出力する。
The dither PROM 9 stores 2 of the given address data.
The bits are used to select the dither type, and the remaining 6 bits are used to select the dither type.
One point of the ×8 dither pattern is selected. The comparator 10 compares the output data of the dithering PROM 9 with the average density value from the average density calculation circuit 4, and outputs data obtained by converting the average density into binary data using the dither method.

コンパレータ7の出力は、オア回路11に与えられる。The output of the comparator 7 is given to an OR circuit 11.

コンパレータ8とコンパレータ10の出力は、アンド回
路12に与えられ、このアンド回路12の出力はオア回
路11に与えられる。オア回路11の出力は、この画像
信号2値化装置の端子13に出力される。
The outputs of comparator 8 and comparator 10 are applied to an AND circuit 12, and the output of this AND circuit 12 is applied to an OR circuit 11. The output of the OR circuit 11 is output to a terminal 13 of this image signal binarization device.

いま、2値化する点の濃度値が周囲の濃度の平均値に所
定値を加算した値より大であると、コンパレータ7の出
力は1″になり、端子13は“l”になる。また、2値
化する点の濃度値が周囲の濃度の平均値から所定値を減
算した値より小であると、コンパレータ7.8の出力は
“O″になり、端子13は“0”になる。すなわち、2
値化する点の濃度と周囲の平均濃度とが大きく異なる2
階調の画像例えば文字等のときは、端子13には強制的
に“1″または“0”が出力される。
Now, if the density value of the point to be binarized is larger than the value obtained by adding a predetermined value to the average value of the surrounding density, the output of the comparator 7 becomes 1'', and the terminal 13 becomes "1". , if the density value of the point to be binarized is smaller than the value obtained by subtracting a predetermined value from the average value of the surrounding density, the output of the comparator 7.8 becomes "O" and the terminal 13 becomes "0". .That is, 2
The density of the point to be converted into a value is significantly different from the surrounding average density 2
In the case of a gradation image such as a character, "1" or "0" is forcibly output to the terminal 13.

また、2値化する点の濃度値が周囲の濃度の平均値に所
定値を加算した値より小であり且つ周囲の濃度の平均値
から所定値を減算した値より大であると、コンパレータ
7の出力はO′″になり、コンパレータ8の出力は“1
″になる。そして、コンパレータ10から出力された平
均濃度をディザ法により2値化したデータが、アンド回
路12とオア回路11を介して端子13に出力される。
Further, if the density value of the point to be binarized is smaller than the value obtained by adding the predetermined value to the average value of the surrounding density, and larger than the value obtained by subtracting the predetermined value from the average value of the surrounding density, the comparator 7 output becomes O''', and the output of comparator 8 becomes "1".
Then, data obtained by converting the average density output from the comparator 10 into binary data using the dither method is output to the terminal 13 via the AND circuit 12 and the OR circuit 11.

すなわち、2値化する点の濃度と周囲の平均濃度とが近
い値である多階調の画像例えば写真等のときは、周囲の
濃度の平均値に応じた2値化データが出力される。
That is, in the case of a multi-gradation image, such as a photograph, in which the density of a point to be binarized is close to the average density of the surrounding area, binarized data corresponding to the average value of the surrounding density is output.

〈発明の効果〉 以上説明したように本発明においては、2値化する点の
濃度と周囲の平均濃度とが大きく異なるときは周囲の濃
度との大小関係に応じて強制的に“l”または“O”の
2値化データを出力し、2値化する点の濃度と周囲の平
均濃度とが近いときには平均濃度に応じた2値化データ
を出力するようにしたので、同一原稿内に文字のような
2階調の部分と写真のような多階調の部分が混在する場
合に2階調と多階調の両方の部分をともに忠実に2値化
することができる。また、ディザ化するときに平均値を
用いるので、原画像が網点画像であってもモアレが生じ
ない。
<Effects of the Invention> As explained above, in the present invention, when the density of a point to be binarized and the average density of the surrounding area are significantly different, "l" or Binarized data of "O" is output, and when the density of the point to be binarized is close to the average density of the surrounding area, the binarized data corresponding to the average density is output, so characters can be printed in the same document. When a two-tone part such as a photograph and a multi-tone part such as a photograph coexist, both the two-tone part and the multi-tone part can be faithfully binarized. Furthermore, since the average value is used when dithering, moiré does not occur even if the original image is a halftone image.

【図面の簡単な説明】[Brief explanation of drawings]

図面は本発明実施例の基本構成を示すブロック図である
。 1・・・ADコンバータ 2・・・メモリ 3・・・D形フリップフロップ 4・・・平均濃度演算回路 5・・・加算用PROM 6・・・減算用FROM 7.8.10・・・コンパレータ 9・・・ディザ用PROM 11・・・オア回路 12・・・アンド回路
The drawing is a block diagram showing the basic configuration of an embodiment of the present invention. 1... AD converter 2... Memory 3... D-type flip-flop 4... Average concentration calculation circuit 5... PROM for addition 6... FROM for subtraction 7.8.10... Comparator 9... PROM for dither 11... OR circuit 12... AND circuit

Claims (1)

【特許請求の範囲】[Claims] アナログ画像信号を2値化する装置において、画像の2
値化する点を含む所定範囲の点の濃度の平均値を演算す
る演算手段と、上記2値化する点の濃度値が上記平均値
に所定値を加算した第1の値より大であるかまたは上記
平均値から所定値を減算した第2の値より小であるとき
に上記2値化する点の濃度値と上記第1の値または上記
第2の値との大小関係に応じた2値化データを発生する
第1の2値化データ発生手段と、上記2値化する点の濃
度値が上記第1の値より小であり且つ上記第2の値より
大であるときに上記平均値に応じた2値化データを発生
する第2の2値化データ発生手段とを備えたことを特徴
とする画像信号2値化装置。
In a device that binarizes an analog image signal, two
a calculation means for calculating the average value of the density of points in a predetermined range including the point to be digitized; and whether the density value of the point to be binarized is greater than a first value obtained by adding a predetermined value to the above average value. Or a binary value corresponding to the magnitude relationship between the density value of the point to be binarized and the first value or the second value when the density value is smaller than the second value obtained by subtracting a predetermined value from the average value. a first binarized data generating means for generating binarized data; and a first binarized data generating means that generates the average value when the density value of the point to be binarized is smaller than the first value and larger than the second value. An image signal binarization device comprising: second binarized data generation means for generating binarized data according to.
JP61027092A 1986-02-10 1986-02-10 Picture signal binary-coding device Granted JPS62185467A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP61027092A JPS62185467A (en) 1986-02-10 1986-02-10 Picture signal binary-coding device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP61027092A JPS62185467A (en) 1986-02-10 1986-02-10 Picture signal binary-coding device

Publications (2)

Publication Number Publication Date
JPS62185467A true JPS62185467A (en) 1987-08-13
JPH0551225B2 JPH0551225B2 (en) 1993-08-02

Family

ID=12211431

Family Applications (1)

Application Number Title Priority Date Filing Date
JP61027092A Granted JPS62185467A (en) 1986-02-10 1986-02-10 Picture signal binary-coding device

Country Status (1)

Country Link
JP (1) JPS62185467A (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58220563A (en) * 1982-06-17 1983-12-22 Fujitsu Ltd Character and pattern picture image extracting system
JPS60106269A (en) * 1983-11-15 1985-06-11 Ricoh Co Ltd Transmission system for half-tone image

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58220563A (en) * 1982-06-17 1983-12-22 Fujitsu Ltd Character and pattern picture image extracting system
JPS60106269A (en) * 1983-11-15 1985-06-11 Ricoh Co Ltd Transmission system for half-tone image

Also Published As

Publication number Publication date
JPH0551225B2 (en) 1993-08-02

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