JPH0793684B2 - Image signal processor - Google Patents
Image signal processorInfo
- Publication number
- JPH0793684B2 JPH0793684B2 JP2043011A JP4301190A JPH0793684B2 JP H0793684 B2 JPH0793684 B2 JP H0793684B2 JP 2043011 A JP2043011 A JP 2043011A JP 4301190 A JP4301190 A JP 4301190A JP H0793684 B2 JPH0793684 B2 JP H0793684B2
- Authority
- JP
- Japan
- Prior art keywords
- image signal
- signal level
- distribution
- ranking
- pixel
- 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.)
- Expired - Fee Related
Links
Landscapes
- Facsimile Image Signal Circuits (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は階調画像を数レベル程度の記録系で多値再生す
る機能を備えた画像信号処理装置に関するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image signal processing device having a function of reproducing multi-valued gradation images in a recording system of several levels.
従来の技術 近年、日常業務におけるOAやファクシミリの発展と伴
に、従来の文字や線画に代表される白/黒2値の画像の
ほかに階調画像のより忠実な再現の要望が強まってい
る。特に、数階調程度のプリンタに対する擬似中間調再
現の要望がされている。2. Description of the Related Art In recent years, along with the development of OA and facsimile in daily work, there has been an increasing demand for more faithful reproduction of grayscale images in addition to white / black binary images represented by conventional characters and line drawings. . In particular, there is a demand for pseudo halftone reproduction for a printer having several gradations.
従来よく知られている方法に多値組織ディザ法がある
(小野他、多値ディザ法による中間調信号表示、テレビ
ジョン学会全国大会、1978年)。A well-known method is the multivalued tissue dither method (Ono et al., Halftone signal display by the multivalued dither method, National Conference of the Television Society, 1978).
第4図(a)は、0、1/2、1が記録できる3値化の組
織ディザ法の例である。同図において401は入力信号の
端子、402は後述する比較器の出力端子、403は入力信号
の端子401から入力される画像信号と後述する閾値マト
リックス404の閾値信号とを比較して出力する比較器、4
04は比較器403に閾値信号を与える閾値マトリックス405
はタイミング信号入力端子である。同図(b)は3値化
の4x4閾値マトリックスの構成を示す。FIG. 4 (a) is an example of a ternary tissue dither method in which 0, 1/2, and 1 can be recorded. In the figure, 401 is an input signal terminal, 402 is an output terminal of a comparator to be described later, and 403 is a comparison for comparing and outputting an image signal input from the input signal terminal 401 and a threshold signal of a threshold matrix 404 described later. Bowl, 4
04 is a threshold matrix 405 that provides a threshold signal to the comparator 403.
Is a timing signal input terminal. FIG. 11B shows the structure of a ternary 4 × 4 threshold matrix.
動作原理は、一画素を2分割して1/2以下の濃度は0か1
/2で、1/2以上の濃度は1で記録する。従って0〜1/2の
間に分布する閾値マトリックスAijと1/2〜1の間に分布
する閾値マトリックスBijを用意し、注目画素の濃度Iij
を比較することにより記録レベルPijが定まる。即ち、 Iij<Aij Pij=0 AijIijBij Pij=1/2 Bij<Iij Pij=1 と表すことができる。The operating principle is that one pixel is divided into two, and the density below 1/2 is 0 or 1
At / 2, the density above 1/2 is recorded as 1. Therefore, the threshold matrix Aij distributed between 0 and 1/2 and the threshold matrix Bij distributed between 1/2 and 1 are prepared, and the density Iij of the pixel of interest is
The recording level Pij is determined by comparing That is, it can be expressed as Iij <Aij Pij = 0 AijIijBij Pij = 1/2 Bij <Iij Pij = 1.
一般に、記録できるレベル数Lはマトリックスサイズを
nxn、多値化のレベル数をmとすると、L=(m−1)
×n2+1で表される。4×4の3値化の場合はL=(3
−1)×42+1=33レベル表すことができる。同サイズ
のマトリックスで4値は49、5値は65、6値は67レベル
を表すことができる。さらにマトリックスサイズを8×
8とすると、4値では193レベルを表現できる。Generally, the number of levels L that can be recorded is the matrix size.
If nxn and the number of multi-valued levels are m, L = (m-1)
It is represented by × n 2 +1. In the case of 4 × 4 ternarization, L = (3
−1) × 4 2 + 1 = 33 levels can be represented. In a matrix of the same size, 4 levels can represent 49 levels, 5 levels can represent 65 levels, and 6 levels can represent 67 levels. Furthermore, the matrix size is 8 ×
If it is 8, four levels can represent 193 levels.
発明が解決しようとする課題 さて、上記多値組織ディザ法は小さなマトリックスサイ
ズでも1画素を複数に分解することによって多くの階調
レベル数を表現できるが、更に高階調性を得ようとする
とマトリックスサイズを大きくする必要がある。高分解
能を得るためにはマトリックスサイズを小さくしなけれ
ばならないという矛盾があるため階調特性と高分解能特
性の両立に限界があり問題であった。The multi-valued tissue dither method described above can express a large number of gradation levels by decomposing one pixel into a plurality even with a small matrix size. Need to increase size. Since there is a contradiction that the matrix size must be reduced in order to obtain high resolution, there is a limit in compatibility between the gradation characteristics and the high resolution characteristics, which is a problem.
本発明は、上記課題を解消し、数階調程度の濃度を表現
できる記録、表示系に対して多値化画像信号を出力し高
品位に再生できる画像処理信号処理装置を提供するもの
でる。The present invention solves the above problems and provides an image processing signal processing device capable of outputting multi-valued image signals to a recording and display system capable of expressing densities of several gradations and reproducing them in high quality.
課題を解決するための手段 本発明は、 (1)原画像における各画素の再配分画像信号レベルを
記憶する再配分用記憶手段の所定位置におけるM個の画
像信号レベルの和Smと一画素前に処理したときに発生し
た配分誤差enを求め、画像信号の最大値Cを(nレベル
−1)で除算したレベルに設定した所定の画像信号レベ
ルCnの配分数Nと残差Aを求め、前記所定の画像信号レ
ベルCnを1/2に除算した半値画像信号レベルCn/2と前記
残差Aとを比較し、前記残差Aが前記半値画像信号レベ
ルCn/2と等しいか又は大きいとき、前記配分数Nに1を
加えた新たな補正配分数N+1と、また前記残差Aが前
記半値画像信号レベルCn/2より小さいとき、そのまま前
記配分数Nと決定する配分値演算手段と、 (2)原画像における各画素の画像信号レベルを記憶す
る順位付け用記憶手段の前記所定位置と対応した画素の
一部に近傍補正量Ebを加えたM個の画素の画像信号レベ
ルの値により画素順位を決定する順位決定手段と、 (3)前記画素順位により前記配分数N(又はN+1)
と前記M個の画素数との関係がN(又はN+1)<Mの
とき、前記所定の画像信号レベルCnと0を割り当て、前
記配分数N(又はN+1)と前記M個の画素数との関係
がN(又はN+1)=Mのとき、前記所定の画像信号レ
ベルCnを割り当て、更に、前記配分数N(又はN+1)
と前記M個の画素数との関係がN(又はN+1)>Mの
とき、すでに前記画素順位に従って配分した前記所定の
画像信号レベルCnにN(又はN+1)個の画像信号レベ
ルCnを再び前記画素順位に従って加算して決定した結果
を、前記再配分用記憶手段の所定位置のM個の画素に割
り当てて多値化画像信号レベルとする再配分手段と、 (4)順位付補正量Ecを記憶する補正量記憶手段の前記
所定位置と対応する画素の近傍の順位付補正量Ecから前
記近傍補正量Ebを演算し前記順位決定手段に与え、さら
に前記順位付補正量Ecと前記順位付用記憶手段の画素の
一部の画像信号レベルと前記多値化画像信号レベルとか
ら新たな順位付補正量Ecを演算する順位付補正手段と、 (5)前記配分値演算手段により求めた総和Sと前記配
分数と残差Aとから配分誤差enを演算し、前記配分値演
算手段に与える配分値演算手段とを具備した画像信号処
理装置とを設けたものである。Means for Solving the Problems The present invention includes (1) a sum Sm of M image signal levels at a predetermined position of a redistributed storage means for storing a redistributed image signal level of each pixel in an original image and one pixel before The distribution error en generated when the processing is performed is calculated, and the distribution number N and the residual A of the predetermined image signal level Cn set to the level obtained by dividing the maximum value C of the image signal by (n level-1) are calculated. A half-value image signal level Cn / 2 obtained by dividing the predetermined image signal level Cn by 1/2 is compared with the residual A. When the residual A is equal to or larger than the half-value image signal level Cn / 2. A new corrected distribution number N + 1 obtained by adding 1 to the distribution number N, and a distribution value calculation means for determining the distribution number N as it is when the residual A is smaller than the half-value image signal level Cn / 2, (2) Store the image signal level of each pixel in the original image Order determining means for determining the pixel order based on the image signal level values of M pixels obtained by adding the neighborhood correction amount Eb to a part of the pixels corresponding to the predetermined position in the ordering storage means; (3) the pixel The distribution number N (or N + 1) depending on the rank
And the number of M pixels is N (or N + 1) <M, the predetermined image signal level Cn and 0 are assigned, and the distribution number N (or N + 1) and the number of M pixels are assigned. When the relationship is N (or N + 1) = M, the predetermined image signal level Cn is assigned, and the distribution number N (or N + 1) is further assigned.
And the number of the M pixels is N (or N + 1)> M, the N (or N + 1) image signal levels Cn are again added to the predetermined image signal level Cn already distributed according to the pixel order. Redistribution means for allocating the result determined by addition according to the pixel order to the M pixels at predetermined positions of the redistribution storage means to obtain a multi-valued image signal level, and (4) the ordered correction amount Ec The neighborhood correction amount Eb is calculated from the ranking correction amount Ec in the vicinity of the pixel corresponding to the predetermined position of the correction amount storage means to be stored and given to the ranking determining means, and the ranking correction amount Ec and the ranking A ranking correction means for calculating a new ranking correction amount Ec from the image signal level of a part of the pixels of the storage means and the multi-valued image signal level, and (5) the sum S obtained by the distribution value calculation means. And the distribution number and the residual A It calculates an error e n, is provided with a image signal processing apparatus and a distribution value calculating means for providing the distribution value calculating means.
作用 本発明は上記手段により、原画像の濃度レベルに応じて
再生画像の数階調濃度レベルの黒画素密度を決定すると
共に原画像の濃度レベル変化に応じて再生画像の黒濃度
レベルの画素配置を決定し、数階調程度を表現できる記
録、表示系に対して、滑らかで高品位な擬似中間調画像
再現をするものである。According to the present invention, by the above means, the black pixel density of several gradation density levels of the reproduced image is determined according to the density level of the original image, and the pixel arrangement of the black density level of the reproduced image is determined according to the density level change of the original image. Is determined, and a smooth and high-quality pseudo-halftone image is reproduced for a recording and display system capable of expressing several gradations.
実施例 第1図は本発明の一実施例における画像信号処理装置の
ブロック図を示すものである。本実施例では前記発明の
構成(1)、(2)、(3)におけるM個を4個とし、
構成(5)における近傍の順位付補正量Ecは4個とする
説明にしている。説明の都合上、各画素には次のような
記号を付与している。Embodiment 1 FIG. 1 is a block diagram of an image signal processing apparatus according to an embodiment of the present invention. In this embodiment, the number M in the configurations (1), (2), and (3) of the invention is four,
It is assumed that the neighboring correction amount Ec in the configuration (5) is four. For convenience of explanation, the following symbols are given to each pixel.
構成(1)、(3)の4個の画素はR00、R01、R10、R11
とし 構成(2)の4個の画素はO00、O01、O10、O11とし 構成(5)の近傍の順位付補正量Ecの記憶位置はEc1、E
c2、Ec3、Ec4とし、新たな順位付補正量Ecの記憶位置は
Ec5とする。各画素の画像空間上の対応位置はR00とO00
とEc5が同じ位置に対応する。The four pixels of the configurations (1) and (3) are R 00 , R 01 , R 10 and R 11
The four pixels of the configuration (2) are O 00 , O 01 , O 10 , and O 11, and the storage positions of the ordered correction amounts Ec in the vicinity of the configuration (5) are Ec 1 , E.
c 2 , Ec 3 , and Ec 4, and the storage position of the new ranking correction amount Ec is
Ec 5 The corresponding position of each pixel in the image space is R 00 and O 00
And Ec 5 correspond to the same position.
前記各記号グループを走査窓と定義し、R00、R01、
R10、R11を走査窓Wrとして、O00、O01、O10、O11を走査
窓W0とし、Ec1、Ec2、Ec3、Ec4、Ec5を走査窓Weとす
る。第1図において各走査窓はそれぞれの対応する記憶
手段上を原画像の主走査とともに右方向へ移動していく
ものとする。Each of the symbol groups is defined as a scanning window, and R 00 , R 01 ,
Let R 10 , R 11 be the scanning window Wr, O 00 , O 01 , O 10 , O 11 be the scanning window W 0, and Ec 1 , Ec 2 , Ec 3 , Ec 4 , Ec 5 be the scanning window We. In FIG. 1, it is assumed that each scanning window moves to the right along with the main scanning of the original image on the corresponding storage means.
第1図において、1は原画像を走査し画像信号レベルを
出力する原画像走査手段、2は原画像走査手段1の出力
信号である原画像の画像信号レベルと後述する再配分手
段の出力信号である再配分用画像信号レベルとを入力と
して記憶し、走査窓Wrの4個の画素R00、R01、R10、R11
の画像信号レベルを出力とする再配分用記憶手段、3は
再配分用記憶手段2の出力信号である走査窓Wrの4個の
画素R00、R01、R10、R11の画像信号レベルと後述する配
分誤差演算手段10の出力信号である配分誤差enを入力し
て、加算した和Sを求め、画像信号の最大値Cをn値−
1で除算した画像信号レベルCnの配分数Nと残差Aを求
め、画像信号レベルCnを1/2に除算した半値画像信号レ
ベルCn/2と残差Aとを比較し、残差Aが半値画像信号レ
ベルと等しいか又は大きいとき、配分数Nに1を加えた
新たな補正配分数N+1を、又残差Aが半値画像信号レ
ベルより小さいとき、そのまま配分数Nを出力する配分
値演算手段、4は走査手段1の出力信号である原画像の
画像信号レベルを入力として記憶し走査窓W0の4個の画
素O00、O01、O10、O11の画像信号レベルを出力とする順
位付用記憶手段、5は順位付用記憶手段4の出力信号で
ある走査窓W0の4個の画素O00、O01、O10、O11の画像信
号レベルと後述する順位付補正手段の出力である近傍補
正量Ebを入力とし、4個の画素の画像信号レベルの比較
により画素順位を決定しそれを出力とする順位決定手段
である。6は再配分演算手段3の出力信号である配分数
N(又はN+1)と順位決定手段5の出力手段である画
素順位とを入力として、画素順位に応じて前記配分数N
(又はN+1)と走査窓Wrの4画素数とを比較し、N
(又はN+1)<4個のとき、所定の画像信号レベルCn
と0との配分を、又、N(又はN+1)=4個のとき所
定の画像信号レベルCnを配分し、また、N(又はN+
1)>4個のとき、所定の画像信号レベルCnを画素順位
に応じてM個配分し、更に再び〔N(又はN+1)〕個
の画像信号レベルCnを先の順位に応じて割当てた画像信
号レベルCnに加算して決定した結果を再配分用画像信号
レベルとして出力する再配分手段、7は配分値演算手段
6の出力である総和Sと残差Aと配分数N(又はN+
1)を入力して配分誤差enを演算し出力する配分誤差演
算手段、8はW0の画素O00の画像信号レベルと再配分用
記憶手段2の出力信号である再配分済画素R00の多値化
画像信号レベルと後述する補正量記憶手段の出力信号で
ある順位付補正量Ecとを入力とし後述する演算により近
傍補正量Ebと新たな順位付補正量Ecとを出力とする順位
付補正手段、9は既に記憶してある順位付補正量Ecを出
力とし順位付補正手段8の出力信号である新たな順位付
補正量Ecを記憶する補正量記憶手段、10は再配分用記憶
手段2の出力信号である再配分済画素R00の多値化画像
信号レベルを入力して多値画像を記録又は表示する画像
記録・表示手段である。In FIG. 1, 1 is an original image scanning means for scanning an original image and outputting an image signal level, 2 is an image signal level of an original image which is an output signal of the original image scanning means 1 and an output signal of a redistribution means which will be described later. And the redistributed image signal level as the input, and the four pixels R 00 , R 01 , R 10 , and R 11 of the scanning window Wr are stored.
Image signal level of the four pixels R 00 , R 01 , R 10 , and R 11 of the scanning window Wr, which is the output signal of the redistribution memory unit 2, And the distribution error e n , which is an output signal of the distribution error calculating means 10, which will be described later, is added to obtain the sum S, and the maximum value C of the image signal is set to the n-value.
The distribution number N of the image signal level Cn divided by 1 and the residual A are obtained, and the half value image signal level Cn / 2 obtained by dividing the image signal level Cn by 1/2 is compared with the residual A. When the value is equal to or larger than the half-value image signal level, a new correction distribution number N + 1 obtained by adding 1 to the distribution number N is output. When the residual A is smaller than the half-value image signal level, the distribution number N is output as it is. The means 4 stores as input the image signal level of the original image which is the output signal of the scanning means 1 and outputs the image signal levels of the four pixels O 00 , O 01 , O 10 and O 11 of the scanning window W 0. The storage means for ranking 5 is an output signal of the storage means for ranking 4, and the image signal levels of the four pixels O 00 , O 01 , O 10 , and O 11 of the scanning window W 0 and the ranking correction described later. The pixel order is determined by comparing the image signal levels of four pixels with the neighborhood correction amount Eb which is the output of the means as an input. A rank determination unit that it output. Reference numeral 6 is an input of the distribution number N (or N + 1) which is the output signal of the redistribution calculating means 3 and the pixel order which is the output means of the order determining means 5, and the distribution number N according to the pixel order.
(Or N + 1) is compared with the number of four pixels of the scanning window Wr, and N
When (or N + 1) <4, a predetermined image signal level Cn
And 0, or a predetermined image signal level Cn when N (or N + 1) = 4, and N (or N +).
1) When> 4, an image in which M predetermined image signal levels Cn are distributed according to the pixel rank, and [N (or N + 1)] image signal levels Cn are again allocated according to the previous rank The redistribution means for outputting the result determined by adding to the signal level Cn as the image signal level for redistribution, and 7 is the sum S, the residual difference A and the distribution number N (or N +) output from the distribution value calculation means 6.
Distribution errors calculating means for calculating and outputting the Enter distribution errors e n 1), 8 redistribution already pixels is an image signal level and reallocation output signal of the memory means 2 of pixel O 00 of W 0 is R 00 The multi-valued image signal level of and the prioritized correction amount Ec which is the output signal of the later-described correction amount storage means are input, and the neighborhood correction amount Eb and the new prioritized correction amount Ec are output by the operation described later. Reference numeral correction means, 9 is a correction amount storage means for outputting the new prioritized correction quantity Ec which is the output signal of the prioritized correction means 8, and 10 is a memory for redistribution. It is an image recording / display means for inputting the multi-valued image signal level of the redistributed pixel R 00 which is the output signal of the means 2 and recording or displaying the multi-valued image.
第2図は本実施例の具体的な回路図で第1図で示す画像
信号処理装置のブロック図の構成の主要部である再配分
用記憶手段2〜補正量記憶手段9をマイクロコンピュー
タで実現したものである。第2図において、11は原画像
走査手段1の出力信号である原画像の画像信号レベルを
入力する入力端子である。インプットポート12はゲート
より構成されており、CPU13より信号線14を介して与え
られる選択信号により入力端子11からの画像信号レベル
をCPU13へ出力する。ROM15にはCPU13を制御するプログ
ラムが込まれており、CPU13はこのプログラムに従って
インプットポート12より必要とされる外部データを取込
んだり、あるいはRAM16との間でデータの授受を行なっ
たりしながら演算処理し、必要に応じて処理したデータ
をアウトプットポート17へ出力する。アウトプットポー
ト17はラッチ回路より構成されており、信号線18を介し
てアウトプットポート17へ与えられるCPU13からの出力
ポート指定信号を受けて、そのポートにデータを一時記
憶する。19はアウトプットポート17に一時記憶されてい
るデータを多値化した画像信号レベルとして画像信号記
録・表示手段10へ出力する出力端子である。FIG. 2 is a concrete circuit diagram of this embodiment, and the redistribution memory unit 2 to the correction amount memory unit 9 which are the main parts of the configuration of the block diagram of the image signal processing apparatus shown in FIG. 1 are realized by a microcomputer. It was done. In FIG. 2, reference numeral 11 is an input terminal for inputting the image signal level of the original image which is the output signal of the original image scanning means 1. The input port 12 is composed of a gate, and outputs the image signal level from the input terminal 11 to the CPU 13 in response to a selection signal given from the CPU 13 via the signal line 14. A program for controlling the CPU 13 is embedded in the ROM 15, and the CPU 13 performs arithmetic processing while fetching external data required from the input port 12 or exchanging data with the RAM 16 according to this program. Then, the data processed as necessary is output to the output port 17. The output port 17 is composed of a latch circuit, receives an output port designation signal from the CPU 13 given to the output port 17 via the signal line 18, and temporarily stores data in the port. An output terminal 19 outputs the data temporarily stored in the output port 17 to the image signal recording / display means 10 as a multi-valued image signal level.
なお、CPU13、ROM15、RAM16は周知のマイクロコンピュ
ータにより構成することができる。The CPU 13, ROM 15, and RAM 16 can be configured by a well-known microcomputer.
ROM15に書きこまれているプログラムをフローチャート
で示すと第3図のようになる。以下第3図に従って第1
図に示した画像信号処理装置の動作を説明する。The flow chart of the program written in ROM15 is shown in Fig. 3. 1st according to FIG. 3 below
The operation of the image signal processing device shown in the figure will be described.
プログラムがスタートすると、まず再配分用記憶手段
2、順位付用記憶手段4、補正量記憶手段9、配分誤差
演算手段10の内容を0クリアし初期設定を行う。(ステ
ップ1) 次に原画像信号を再配分用記憶手段2の走査窓Wrの画素
R11と順位付け記憶手段4の走査窓W0の画素O11に読み込
む(ステップ2)。When the program starts, first, the contents of the redistribution storage unit 2, the ranking storage unit 4, the correction amount storage unit 9, and the distribution error calculation unit 10 are cleared to 0 and initialization is performed. (Step 1) Next, the original image signal is assigned to the pixels of the scanning window Wr of the memory unit 2 for redistribute
R 11 and the pixel O 11 of the scanning window W 0 of the ranking storage means 4 are read (step 2).
次に再配分用記憶手段2の走査窓Wr内の4個の画素
R00、R01、R10、R11の画像信号レベル加算値Smと、一画
素前に発生した配分誤差enとの和S(=Sm+en)を演算
する。次に画像信号の最大値Cを記録・表示できる濃度
レベル数n−1で除算した画像信号レベルCnを求め、和
S=Cn×N+Aとなる画像信号レベルCnの配分数Nと残
差Aを演算し、更に画像信号レベルCnの半値画像信号レ
ベルCn/2と残差Aとを比較して残差AがA≧Cn/2のとき
画像信号Cnの配分数をN+1とし、残差AがA<Cn/2の
とき、配分数をNとする。(ステップ3)。Next, four pixels in the scanning window Wr of the redistribution memory unit 2
R 00, R 01, R 10 , and calculates an image signal level added value Sm of R 11, the sum S (= Sm + e n) between the distribution errors e n that occurred before one pixel. Next, the image signal level Cn is obtained by dividing the maximum value C of the image signal by the number n-1 of density levels that can be recorded / displayed, and the distribution number N and the residual A of the image signal level Cn that gives the sum S = Cn × N + A are obtained. Further, the half value image signal level Cn / 2 of the image signal level Cn is compared with the residual A. When the residual A is A ≧ Cn / 2, the distribution number of the image signal Cn is set to N + 1, and the residual A is When A <Cn / 2, the distribution number is N. (Step 3).
次に補正量記憶手段9の走査窓Wc内の順位付補正量記憶
位置Ec1、Ec2、Ec5、Ec4、の4個の順位付補正量Ecの平
均値Ecaと係数Kaから近傍補正量Eb(=Ka×Eca)を演算
する(ステップ4)。Next, the neighborhood correction is performed from the average value Eca and the coefficient Ka of the four ordered correction amounts Ec of the ordered correction amount storage positions Ec 1 , Ec 2 , Ec 5 , Ec 4 in the scanning window Wc of the correction amount storage means 9. The amount Eb (= Ka × Eca) is calculated (step 4).
次に順位付用記憶手段4の走査窓W0の画素O00の画像信
号レベルに近傍補正量Ebを加算した後、4個の画素
O00、O01、O10、O11の画像信号レベルをそれぞれ比較し
大きい順に画素順位を決定する(ステップ5)。Next, after the neighborhood correction amount Eb is added to the image signal level of the pixel O 00 of the scanning window W 0 of the ranking storage means 4, four pixels are added.
The image signal levels of O 00 , O 01 , O 10 , and O 11 are compared with each other, and the pixel order is determined in descending order (step 5).
次にステップ3で求めた配分数N(又はN+1)がN
(又はN+1)<4のとき、ステップ5で求めた画素順
位に従って画像信号レベルCnと0を再配用記憶手段2の
走査窓Wrの4個の画素R00、R01、R10、R11の画像信号レ
ベルとし、又N(又はN+1)=4のときはCnを走査窓
Wrの4個の画素R00、R01、R10、R11の画像信号レベルと
する。また配分数N(又はN+1)がN(又はN+1)
>4のとき、すでに画素順位に従って配分した画像信号
レベルCnに〔N(又はN+1)〕個の画像信号レベルCn
を再びステップ5で求めた画素順位に従って加算して決
定した結果を再配分用記憶手段2の走査窓Wrの4個の画
素R00、R01、R10、R11の画像信号レベルとし、そして再
配分済画素R00を多値化画像信号レベルとする(ステッ
プ6)。Next, the distribution number N (or N + 1) obtained in step 3 is N
When (or N + 1) <4, the image signal levels Cn and 0 are assigned to the four pixels R 00 , R 01 , R 10 , R 11 of the scanning window Wr of the redistribution storage unit 2 in accordance with the pixel order obtained in step 5. The image signal level of, and when N (or N + 1) = 4, Cn is the scanning window
The image signal levels of the four Wr pixels R 00 , R 01 , R 10 , and R 11 are set. Further, the distribution number N (or N + 1) is N (or N + 1)
When> 4, [N (or N + 1)] image signal levels Cn are added to the image signal levels Cn already allocated according to the pixel order.
Is again added according to the pixel order obtained in step 5 and the result is determined as the image signal level of the four pixels R 00 , R 01 , R 10 and R 11 of the scanning window Wr of the redistribution storage means 2, and The redistributed pixel R 00 is set to the multilevel image signal level (step 6).
次にステップ3で求めた総和Sと、画像信号レベルCnの
配分数N(又はN+1)と、残差Aから配分誤差enを次
のように求める。配分数がN+1のとき、配分誤差en
(=S−(Cn×(N+1))配分数がNのとき、配分誤
差en(=A)なる演算し一時レジスタに記憶する。(ス
テップ7)。Next, the distribution error en is calculated from the sum S calculated in step 3, the distribution number N (or N + 1) of the image signal level Cn, and the residual A as follows. When the number of allocations is N + 1, allocation error en
(= S- (when Cn × (N + 1)) number distribution is N, and stores the distribution errors e n (= A) consisting calculated temporary register. (Step 7).
次にステップ4における平均値Ecaと係数Kbを集算した
値に走査窓W0内の画素O00の画像信号レベルを加算し、
その値とステップ6における再配分済画素R00の多値化
画像信号レベルとの差分を新たな順位付補正量Ecとし走
査窓We内の画素Ec5に記憶する(ステップ8)。Next, the image signal level of the pixel O 00 in the scanning window W 0 is added to the sum of the average value Eca and the coefficient Kb in step 4,
The difference between that value and the multi-valued image signal level of the redistributed pixel R 00 in step 6 is stored as a new ranked correction amount Ec in the pixel Ec 5 in the scanning window We (step 8).
次にステップ6で求めた再配分済画素R00の多値化画像
信号レベルを画像記録・表示手段10へ出力する(ステッ
プ9)。Next, the multi-valued image signal level of the redistributed pixel R 00 obtained in step 6 is output to the image recording / display means 10 (step 9).
次にすべての原画像信号レベルに対して主走査方向およ
び副走査方向の処理終了判定をし(ステップ10)、未終
了であれば走査窓の移動を行い(ステップ11)ステップ
2より繰返す。もし終了であれば全原画像信号に対して
処理を完了する。ただし、主走査方向の処理が終了する
毎にステップ11において配分誤差enを0クリアする。Next, it is determined whether or not the processing in the main scanning direction and the sub-scanning direction has been completed for all the original image signal levels (step 10), and if not completed, the scanning window is moved (step 11) and the process is repeated from step 2. If completed, the processing is completed for all original image signals. However, it cleared to zero distribution errors e n in step 11 each time the process in the main scanning direction is completed.
なお上記説明ではマイクロコンピュータにより再配分記
憶手段2〜補正量記憶手段9を実現したが、これらの手
段はそれぞれ論理回路、外部メモリ等により実現するこ
ともできる。In the above description, the redistribution storage unit 2 to the correction amount storage unit 9 are realized by the microcomputer, but these units can be realized by a logic circuit, an external memory or the like.
さらに順位付補正手段8の係数Kaは1/2L(ただし、Lは
正の整数)にすることにより、また係数Kbは1−1/2
m(ただし、mは正の整数)にすることによりマイクロ
コンピュータで実現した場合には演算を容易にすること
ができ、論理回路で実現した場合にはハードウエアを軽
減することができる。Further, the coefficient Ka of the ranking correction means 8 is set to 1/2 L (where L is a positive integer), and the coefficient Kb is 1-1 / 2.
By setting m (where m is a positive integer), the operation can be facilitated when implemented by a microcomputer, and the hardware can be reduced when implemented by a logic circuit.
発明の効果 以上のように本発明によれば画像信号の最大値Cをnレ
ベルの出力階調数n−1で除算した画像信号レベルCnを
配分値とし、総和Sから得られるCnの配分数Nと残差A
を求め、その残差Aを半値画像信号レベルCn/2と比較し
て、Cnの配分数を制御し、配分誤差enを小さくすること
によって、滑らかな再生画像を得ることができる。As described above, according to the present invention, the image signal level Cn obtained by dividing the maximum value C of the image signal by the output gradation number n-1 of the n level is used as the distribution value, and the distribution number of Cn obtained from the sum S is calculated. N and residual A
The calculated, by comparing the residual A half-value image signal level Cn / 2, to control the allocation number Cn, by reducing the distribution errors e n, it is possible to obtain a smooth reproduced picture.
第1図は本発明の一実施例における画像信号処理装置の
ブロック結線図、第2図は同装置をマイクロコンピュー
タで実現した具体的な回路図、第3図は本実施例の動作
を説明するフローチャート、第4図は従来の多値組織デ
ィザ法を実現する装置のブロック結線図である。 1…原画像走査手段、2…再配分用記憶手段、3…配分
値演算手段、4…順位付用記憶手段、5…順位決定手
段、6…再配分手段、7…配分誤差演算手段、8…順位
付補正手段、9…補正量記憶手段、10…画像記録・表示
手段、11…入力端子、12…インプットポート、13…CP
U、14,18…信号線、15…ROM、16…RAM、17…アウトプッ
トポート、19…出力端子。FIG. 1 is a block connection diagram of an image signal processing apparatus according to an embodiment of the present invention, FIG. 2 is a concrete circuit diagram of the apparatus realized by a microcomputer, and FIG. 3 is a diagram for explaining the operation of the present embodiment. A flow chart, FIG. 4 is a block connection diagram of an apparatus for realizing the conventional multi-valued tissue dither method. DESCRIPTION OF SYMBOLS 1 ... Original image scanning means, 2 ... Redistribution storage means, 3 ... Distribution value calculation means, 4 ... Ranking storage means, 5 ... Ranking determination means, 6 ... Redistribution means, 7 ... Distribution error calculation means, 8 ... Ranking correction means, 9 ... Correction amount storage means, 10 ... Image recording / display means, 11 ... Input terminal, 12 ... Input port, 13 ... CP
U, 14, 18 ... Signal line, 15 ... ROM, 16 ... RAM, 17 ... Output port, 19 ... Output terminal.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 小寺 宏曄 神奈川県川崎市多摩区東三田3丁目10番1 号 松下技研株式会社内 (56)参考文献 特開 昭59−61280(JP,A) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirohisa Kodera 3-10-1 Higashisanda, Tama-ku, Kawasaki City, Kanagawa Prefecture Matsushita Giken Co., Ltd. (56) Reference JP-A-59-61280 (JP, A)
Claims (3)
ベルを記憶する再配分用記憶手段の所定位置におけるM
個の画像信号レベルの和Smと一画素前に処理したときに
発生した配分誤差enを求め、画像信号の最大値Cを(n
レベル−1)で除算したレベルに設定した所定の画像信
号レベルCnの配分数Nと残差Aを求め、前記所定の画像
信号レベルCnを1/2に除算した半値画像信号レベルCn/2
と前記残差Aとを比較し、前記残差Aが前記半値画像信
号レベルCn/2と等しいか又は大きいとき、前記配分数N
に1を加えた新たな補正配分数N+1と、また前記残差
Aが前記半値画像信号レベルCn/2より小さいとき、その
まま前記配分数Nと決定する配分値演算手段と、原画像
における各画素の画像信号レベルを記憶する順位付用記
憶手段の前記所定位置と対応した画素の一部に近傍補正
量Ebを加えたM個の画素の画像信号レベルの値により画
素順位を決定する順位決定手段と、前記画素順位により
前記配分数N(又はN+1)と前記M個の画素数との関
係がN(又はN+1)<Mのとき、前記所定の画像信号
レベルCnと0を割り当て、前記配分数N(又はN+1)
と前記M個の画素数との関係がN(又はN+1)=Mの
とき、前記所定の画像信号レベルCnを割り当て更に、前
記配分数N(又はN+1)と前記M個の画素数との関係
がN(又はN+1)>Mのとき、すでに前記画素順位に
従って配分した前記所定の画像信号レベルCnにN(又は
N+1)個の画像信号レベルCnを再び前記画素順位に従
って加算して決定した結果を、前記再配分用記憶手段の
所定位置のM個の画素に割り当てて多値化画像信号レベ
ルとする再配分手段と、順位付補正量Ecを記憶する補正
量記憶手段の前記所定位置と対応する画素の近傍の順位
付補正量Ecから前記近傍補正量Ebを演算し前記順位決定
手段に与え、さらに前記順位付補正量Ecと前記順位付用
記憶手段の画素の一部の画像信号レベルと前記多値化画
像信号レベルとから新たな順位付補正量Ecを演算する順
位付補正手段と、前記配分値演算手段により求めた総和
Sと前記配分数N(又はN+1)と残差Aとから配分誤
差enを演算し、前記配分値演算手段に与える配分誤差演
算手段とを具備した画像信号処理装置。1. M at a predetermined position of a redistribution memory means for storing a redistribution image signal level of each pixel in an original image.
The sum Sm of the image signal levels and the distribution error en generated when the pixel is processed one pixel before are calculated, and the maximum value C of the image signal is calculated as (n
Half-value image signal level Cn / 2 obtained by obtaining the distribution number N and the residual A of the predetermined image signal level Cn set to the level divided by level-1) and dividing the predetermined image signal level Cn by 1/2.
And the residual A are compared, and when the residual A is equal to or larger than the half-value image signal level Cn / 2, the distribution number N
A new correction distribution number N + 1 obtained by adding 1 to the above, and when the residual A is smaller than the half-value image signal level Cn / 2, the distribution value calculating means for determining the distribution number N as it is, and each pixel in the original image. Order determining means for determining the pixel order based on the image signal level values of M pixels obtained by adding the neighborhood correction amount Eb to a part of the pixels corresponding to the predetermined position of the ordering storage means for storing the image signal level of And when the relationship between the distribution number N (or N + 1) and the number of M pixels is N (or N + 1) <M according to the pixel order, the predetermined image signal level Cn and 0 are assigned, and the distribution number is N (or N + 1)
And the number of M pixels is N (or N + 1) = M, the predetermined image signal level Cn is assigned and the relation between the number N (or N + 1) of distribution and the number of M pixels is assigned. Is N (or N + 1)> M, N (or N + 1) image signal levels Cn are added again to the predetermined image signal level Cn already distributed according to the pixel order to determine the result. Corresponding to the redistribution means for allocating to the M pixels at the predetermined position of the redistribution memory means to obtain the multi-valued image signal level, and the predetermined position of the correction amount storage means for storing the ranked correction amount Ec. The neighborhood correction amount Eb is calculated from the ranking correction amount Ec in the vicinity of the pixel and given to the ranking determination means, and the ranking correction amount Ec and the image signal level of a part of the pixels of the ranking storage means and the aforesaid New from multilevel image signal level Ranking correction means for calculating a different ranking correction amount Ec, a distribution error en is calculated from the sum S obtained by the distribution value calculation means, the distribution number N (or N + 1) and the residual A, and the distribution value en An image signal processing device comprising: a distribution error calculating means to be given to a calculating means.
平均値Ecaを求め、係数1/2L(ただし、Lは正の整数)
を乗算して、近傍補正量Ebを演算し前記順位決定手段に
与えることを特徴とする請求項1記載の画像信号処理装
置。2. A ranking correction means obtains an average value Eca of neighboring ranking correction amounts Ec, and a coefficient 1/2 L (where L is a positive integer).
2. The image signal processing apparatus according to claim 1, wherein the proximity correction amount Eb is calculated by multiplying by and given to the order determining means.
平均値Ecaを求め、係数1−1/2m(ただし、mは正の整
数)を乗算して、順位付用記憶手段の画素の一部の画像
信号レベルを加算しさらに多値化画像信号レベルを減算
して、新たな順位付補正量Ecを求めることを特徴とする
請求項1記載の画像信号処理装置。3. A ranking correction means obtains an average value Eca of neighboring ranking correction amounts Ec and multiplies it by a coefficient 1-1 / 2 m (where m is a positive integer) to obtain a ranking storage means. 2. The image signal processing device according to claim 1, wherein a new ranked correction amount Ec is obtained by adding the image signal levels of a part of the pixels of the above and further subtracting the multi-valued image signal level.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2043011A JPH0793684B2 (en) | 1990-02-23 | 1990-02-23 | Image signal processor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2043011A JPH0793684B2 (en) | 1990-02-23 | 1990-02-23 | Image signal processor |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH03245674A JPH03245674A (en) | 1991-11-01 |
JPH0793684B2 true JPH0793684B2 (en) | 1995-10-09 |
Family
ID=12652045
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2043011A Expired - Fee Related JPH0793684B2 (en) | 1990-02-23 | 1990-02-23 | Image signal processor |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0793684B2 (en) |
-
1990
- 1990-02-23 JP JP2043011A patent/JPH0793684B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPH03245674A (en) | 1991-11-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4692811A (en) | Apparatus for processing image signal | |
US4551768A (en) | Method and apparatus for processing image signal | |
JPH10271331A (en) | Image processing method and device therefor | |
JP4236804B2 (en) | Image processing method, apparatus and storage medium | |
US5493416A (en) | Method combining error diffusion and traditional halftoning with arbitrary screen orientation | |
JP5013805B2 (en) | Processor-readable storage medium | |
EP0206401A1 (en) | Method of enlarging/reducing a dithered image | |
US6628427B1 (en) | Method and apparatus for image processing which improves performance of gray scale image transformation | |
JPH0793684B2 (en) | Image signal processor | |
JPH0435105B2 (en) | ||
JP2851662B2 (en) | Image processing device | |
JPH02215275A (en) | Image signal processor | |
JP3708191B2 (en) | Image processing device | |
JPH02107064A (en) | Picture signal processor | |
JP3379300B2 (en) | Image processing device | |
JPS6132654A (en) | Picture signal processing device | |
JPH06101788B2 (en) | Image signal processor | |
JP2880561B2 (en) | Image processing device | |
JPH0462507B2 (en) | ||
JPS6132657A (en) | Picture signal processing device | |
JPS6132662A (en) | Picture signal processing device | |
JPH02143875A (en) | Image signal processor | |
JPS6132656A (en) | Picture signal processing device | |
JPH0618437B2 (en) | Image signal processor | |
JPH04428B2 (en) |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
LAPS | Cancellation because of no payment of annual fees |