KR850000039B1 - Control method for reproduction a halftone dot cut away along a picture outline - Google Patents

Abstract

In a method for reproducing a halftone picture by scanning, wherein a brightness and a width of a recording light beam to be projected on a photosensitive material is suitably controlled by means of picture signals obtained from the scanning of an original picture, a control method for reproducing a halftone dot cut away along a picture outline is disclosed, wherein a position of an outline in an original picture is detected, wherein the intersection of the outline with a halftone dot is discriminated by comparing the two positions of the outline and the dot, and wherein a part of the dot positioned inside the outline is exposed by the recording light beam.

Description

Syringe Locking Method

1 is a perspective view showing an example of a conventional apparatus for recording a mesh with a syringe such as a plate making scanner.

2 shows a technique for recording a mesh board image by a conventional method.

3 shows that the mesh board is cut along the outline of the image.

4 to 16 are diagrams for explaining that the principles of the present invention are suitable for various screen angle mesh boards.

17 is a block diagram of a control device used to reproduce a halftone cut along the contour of an image according to the present invention.

The present invention relates to a method and apparatus for reproducing cutout dots along the contour of a reproduced image in an image reproducing apparatus such as a color scanner or a color facsimile for reproducing a mesh screen image using an image scanning recording apparatus. It is about. Various methods are known for reproducing a mesh board image by scanning an original picture.

As an example, Japanese Patent Application Laid-Open No. 54-79701 (Japanese Patent Application No. 52-145683) filed by the applicant of the present invention describes an apparatus for reproducing a mesh wood board image by scanning. Briefly explaining the invention with reference to FIG. 1, the light beam coming from such a light source 1, such as a laser tube, is provided with a first deflector 2, a V-shaped hole 3; It passes along the axis of light through the second deflector 4 and the focusing lens 5.

At this time, a fine line image W is obtained. The deflector used here is known from the fact that the elastic deformation in the ore caused by the ultrasonic wave acts like a diffraction grating. By using such a deflector, the pitch of the diffraction grating can be appropriately changed by adjusting the frequency of ultrasonic waves supplied to the ore. Here the deflection angle of the light beam changes with frequency. The deflection angle can also be adjusted with the deflector. The light beam is deflected in the vertical direction, that is, the "Z" direction, at an appropriate angle according to the frequency of the ultrasonic waves applied from the first deflector 2 to the first deflector 2. Here, the height of the light beam projected onto the hole is changed so that the width of the light beam through the hole is changed. The light beam is deflected in the horizontal direction, i.e., the "Y" direction, at an appropriate angle according to the frequency of the ultrasonic waves applied from the second deflector 4 to the second deflector 4.

Here the position of the light beam through the hole is moved in its width direction. Therefore, by adjusting the frequency of the ultrasonic waves applied to the two deflectors (2) (4) it is possible to change the width and position of the line (W) of the light beam. The shipboard W can be used to reproduce the mesh board image on the photosensitive material provided in the recording cylinder. (See Figure 2)

3 (a), 2 (b) and 2 (c) show three mesh plates having screen angles of 45 degrees, 0 degrees and 15 degrees with respect to the scanning line S. FIG. When the mesh board is divided into left and right portions by the scanning line S, the left length is "L" and the right length is "R". The total length W of the shipboard W is expressed as follows.

W = L + R

In the above-described example, since the pitch of the scanning line of the plate-making color scanner is smaller than the pitch of the screen line in the general mesh board, several scanning lines cross a single halftone region. Therefore, one dot is recorded by one scanning operation of one of several scanning lines.

In Fig. 2 (a) or Fig. 2 (b), a scanning line S which equally divides the halftone region into two parts is selected, and a halftone is recorded along the selected scanning line.

In Fig. 2 (c), a scanning line S that traverses one side of the halftone region is selected for recording the halftone.

Fig. 2 (c) shows a diagonal stone S 'which equally divides the halftone region into two parts. In the vertical direction of the scanning line S, the left length of the halftone region divided by the diagonal S 'is "α", the right length is "β", and the distance between the scanning line S and the diagonal S' is "σ". Where L = α−σ and R = β + σ.

The above formula can also be applied to the second (a) or second (b). However, sigma = 0 in the second (a) and second (b). As a result, "L" and "R" can be obtained with "α" and "β" using the above equation, and the overall length "W" can also be obtained.

이다.The deflection of the light beam can be controlled using the first deflector such that the length of the shipboard W is the entire length W. FIG. Distance between scan line S and full length W solid

to be.

L 이므로 광 비임은 제2편향기에 의해 편향될 것이다. 선상(W)의 중심이 제2(c)도에 도시된 선(C)을 따라 이동되도록 상기의 편향 작동이 제어된다. 이 경우에 망점영역은 화상신호의 온도에 따라 변한다. 두개의 편향기를 제어하여 선상의 폭과 위치를 변경시키면 상기의 현상이 행해진다.In the example of FIG. 2 (a) and FIG. 2 (b), R = L and P = O. Therefore, there is no need to deflect the light beam with the second deflector. But in (III) of Figure 2, R

Since L the light beam will be deflected by the second deflector. The deflection operation is controlled so that the center of the ship W is moved along the line C shown in the second (c) diagram. In this case, the halftone region changes depending on the temperature of the image signal. The above phenomenon is carried out by controlling the two deflectors to change the width and position of the line.

In this way, halftones are always recorded in their full form. However, sometimes in reality the dots must be cut along the outline of the playback picture. In such a case, a good reproduction image may not be obtained unless the dot is cut along the outline.

An object of the present invention relates to a method for improving resolution by cutting a dot in accordance with an image outline and faithfully expressing the outline in a mesh wood image scanning recording means. In the method of scanning according to the present invention for reproducing a mesh board image, the brightness and width of the light beam to be projected onto the photosensitive material are suitably controlled by the image signal obtained by scanning the original picture. The control method for reproducing the halftone cut along the outline of the image consists of detecting the position of the outline in the original picture and comparing the position of the halftone to distinguish the intersection of the outline and the halftone.

Here, the part of the halftone point which is located inside the outline among the halftone points traversed by the outline is exposed by the light beam. In the apparatus for scanning and reproducing a mesh board image according to the present invention, the brightness and width of the light beam to be projected onto the photosensitive material are suitably controlled by the image signal obtained by scanning the original picture. The control device used to reproduce the halftone cut along the outline of the image

end. A width signal oscillator for generating a width signal corresponding to the width of the halftone to be recorded.

I. A position signal oscillator for generating an contour position signal corresponding to the position of the contour in the original picture.

All. Selector for selecting one of two signals by comparing the width signal with the contour position signal.

la. According to the selected signal. There is a controller to control the length of the light beam.

Hereinafter, the present invention will be described in detail with reference to the drawings. In Fig. 3, 50% of the halftone region is cut along the contour E of the reproduced image. That is, there is a 0% halftone region on the left side of the contour line E. FIG. That is, the halftone region on the left side of the contour E is 0%, and the concentration is "0". When the width of the halftone cut along the contour line E is divided into left and right sides by the scanning line S, the left length is "L '" and the right length is "R'".

When the width of one whole halftone dot is divided into left and right sides by the scanning line S, the left length is "L" and the right length is "R". (See FIG. 2) The distance in the left-right direction of the contour line E with respect to the scanning line S is "El" and "Er", respectively.

The following relation is established by the above conditions.

In formulas (1) and (2), "L" and "El" are "+" values on the left side of the scanning line S, "-" values on the right side, and "R" and "Er" are conversely It is a "+" value on the right side of the scanning line S and a "-" value on the left side.

By using "L '" and "R'" obtained from equations (1) and (2), the center position (P) and length (W) of the line W can be expressed as follows.

The mesh board image is composed of several dots, and some of the dots are cut along the image outline. When the ultrasonic frequencies supplied to the two deflectors are controlled according to the values of "W" and "P" obtained in equations (3) and (4), the mesh board image is recorded. It will be described below that the method described above is suitable for various screen angle mesh boards.

Figure 4 (a) shows a mesh board with a screen angle of 0 degrees. Here, the left part of the halftone point is cut by the image limbus line. The halftone is divided into four parts (A) (B) (C) (D). In other words, the portion from the bottom to the intersection of the contour and the bottom edge of the dot is "A", the portion from the intersection of the bottom edge of the dot to the intersection of the contour and the scan line is "B", and the contour The portion from the intersection of the scan line to the intersection of the upper right edge of the contour and the dot is "C", and the portion from the intersection of the upper right edge of the contour and the dot to the top is "D". .

L이다. 그러므로 L'=L 이다.W = L '+ R', El in part (A)

L. Therefore L '= L.

In addition, if we understand that the other contour used to obtain Er exists on the right side outside the halftone region shown, Er> R R '= R. Therefore W = L + R and L = R.

therefore

El<L 이고 Er>R 이다.In part (B), O

El <L and Er> R.

Therefore W = El + R = L '+ R'

In part (C), El <O, Er> R.

therefore

W = R- ｜ Er ｜ = El + R = L '+ R'

In part (D) | E1 |> R

Therefore, E1 + R <O, W = O.

FIG. 4 (b) shows a graph of the value of "W" and FIG. 4 (c) shows a graph of the value of "P". 5 shows a mesh board with a screen angle of 0 degrees. Here, the right part of the halftone point is cut | disconnected by the image outline (E). Similar to the example of FIG. 4 (a), the halftone is divided into four parts (A ') (B') (C ') (D').

R, El>L 그러므로 R'=R, L'=L W=L+R,

이다.Er in part (A ')

R, El> L Therefore, R '= R, L' = LW = L + R,

to be.

Er<R, El>L 이다.O in part (B ')

Er <R, El> L.

이다.Therefore R '= Er, L' = LW = L + Er = L '+ R'

to be.

In the part C ', Er <0, El> L.

Therefore R '= Er, L' = L W = L- | Er | = L + Er = L '+ R'

In part D '| Er |> L.

Therefore L '+ R' <O, W = O.

6 (a), 6 (b), 6 (c) or 6 (d) show a mesh board having a screen angle of 0 degrees. Here, the left and right sides of the halftone are cut by two outlines. The halftone points are divided horizontally, and each part is indicated by a combination of A, B, C or D in FIG. 4 (a) and A ', B' C 'or D' in FIG.

L, Er

R 이다.El in part (A, A ')

L, Er

R is.

이다.Therefore W = L + R = L '+ R'

to be.

L, O

Er<R W=L+Er=L'+R'

이다.El in part (AB ¹ )

L, O

Er <RW = L + Er = L '+ R'

to be.

L, Er<O W=L-｜Er｜= L+Er=L'+R'El in part (A.C ')

L, Er <OW = L- | Er | = L + Er = L '+ R'

In the part A.D ', L' + R '= L- | Er | <O W = O.

El L. Er>R W=El+R=L'+R'

이다.O in part (B.A ')

El L. Er> RW = El + R = L '+ R'

to be.

El<L. O

Er<R W=El+Er=L'+R'

이다.O in part (B.B ')

El <L. O

Er <RW = El + Er = L '+ R'

to be.

El<L. Er<O W=El-｜Er｜=El+Er=L'+R'O in part (B.C ')

El <L. Er <OW = El- ｜ Er ｜ = El + Er = L '+ R'

In the part B.D ', L' + R '= El- | Er | <O W = O.

El <O, Er> R W = R- | El | = El + R = L '+ R' in the part C.A '

Er<R W=Er-｜El｜=El+Er=L'+R'El <O. In the portion (C, B '). O

Er <RW = Er- ｜ El ｜ = El + Er = L '+ R'

El <O. In the portion (C. C '). Er <O L '+ R' =-| El |-| Er | <O W = O.

Such a state does not occur in reality but is theoretically established as described above.

In the part (D. A 'D'), L '+ R' <O W = O.

As described above, when the angle of the mesh board is 0 degrees, equations (3) and (4) are always established on the premise of equations (1) and (2). The above consideration applies equally to the case where the screen angle of the mesh board is 45 degrees as shown in FIG. In the example of FIG. 7, there are four parts A.A ', B.B', and C.B '. The same theory as in FIG. 6 holds for any part of FIG.

Therefore, equation (3) and equation (4) are always established when the screen angle of the mesh board is 45 degrees. Consider the case where the screen angle of the mesh is 15 degrees. Figure 8 (a) shows a mesh board with a screen angle of 15 degrees, and Figures 8 (b) and 8 (c) show changes in the "L" and "R" values that change to record the dot. Is shown as a graph.

Where "L" is always a "+" value and the value of "R" changes from "+" to "-" relative to zero. When the screen angle of the mesh board is -15 degrees, i.e., in the case of a half point inclined opposite to Fig. 8 (a), "L" becomes an image symmetrical with the graph of Fig. 8 (c), and "R" of Fig. 8 (III) is in symmetrical phase with the graph.

9 and 10 illustrate halftones with a screen angle of 15 degrees. Here, the left part of the mesh board is cut | disconnected by the contour line E. FIG. The halftone is divided into A-D parts, similar to that in FIG. 4 (a).

L. Er>R W=L+R=L'=R'

El in part (A)

L. Er> RW = L + R = L '= R'

El <L. In part (B). Er> RW = El + R = L '+ R'

Part C El <L. Er> R (where R is the value "-") W = E1-│R│ = El + R = L '+ R'

El + R <O W = O in part (D)

11 and 12 also show a mesh board with a screen angle of 15 degrees. Here, the right part of the mesh board is cut | disconnected by the outline E. As shown in FIG. In FIG. 11, the halftone is divided into A'-D 'portions similarly to FIG. 5, and in FIG. 12, the halftone is divided into C' and D '' portions.

R W=L+R=L+R'

El> L in part (A '). Er

RW = L + R = L + R '

El> L, Er <R w = L + Er = L '+ R' in part (B ')

El> E in part (C '). Er <R (Er is "-" value) W = L- | Er | = L + Er = L '+ R'

El <L. In part D '. Er> R (Er, R is "-" value) W = L- | R | = L + R = L '+ R'

Er <R, | Er |> L L '+ R' <O. W = O

13 and 14 show a mesh board with a screen angle of 15 degrees. Here the left and the right are cut by two contours. The mesh board is divided into parts, each part being marked by the combination of parts A-D and parts A'-D '' shown in FIGS. 9-12, similarly to FIG. Here, equations (3) and (4) hold. This can be done as described with respect to FIG.

Figure 15 (a) shows a mesh board with a screen angle of 15 degrees. Here, the upper and lower ends are cut by two contour lines E perpendicular to the scan line S. FIG. 15 (b) and 15 (c) show values of "L '" and "R'" in graphs. In this case, either "El" or "Er" may be used to cut the halftone along the contour, or both "El" and "Er" may be used.

When using "El" and "Er" as shown in Fig. 15 (a), "El" and "Er" in part A and part D are "0", part B and part In (C) El> L, Er> R.

El <L, Er <RW = El + Er = L '+ R' = O in part (A)

W = L + R = L '+ R' in part (B)

W = L- | R | = in part (C)

W = El + Er = L '+ R' = O in part D

As shown in FIG. 16, when using only "El", the values of "El" are set so as to satisfy El <-| Rmax | in the portions A and C where halftones are cut.

In this case, in parts A and C, El <L, Er> R L '+ R' = El + R <O W = O.

Even when only "Er" is used, the value of "Er" may be set similarly to satisfy Er <-| Lmax |. From the foregoing, when the conditions shown in equations (1) and (2) are satisfied, the length (W) and center position (P) of the line (W) for recording the halftone cut along the contour are represented by equation (3). It is proved that it is obtained according to Eq. (4). The values "L", "R", "El", and "Er" applied to each of the above formulas may be set as follows.

Since "L" and "R" are values determined by the screen angle and the halftone region, for example, the necessary values of "L" and "R" are stored in the storage device for the previously required angle and halftone of the region. What is necessary is just to output synchronously with scanning at the time of scanning exposure.

The work of such a technique is also described in detail in Japanese Patent Application Laid-Open No. 54-79701 (Japanese Patent Application No. 52-145683) relating to the apparatus shown in FIG. In addition, "El" and "Er" are values determined by the contents of the original picture to be reproduced on the mesh board, and are obtained according to the image signal obtained by photoinjecting the original picture. As an example, image signals of several adjacent scanning lines can be simultaneously accumulated in parallel in the storage device, and the values of "El" and "Er" can be obtained by appropriately processing the accumulated image signals.

Such a method is described in Japanese Patent Laid-Open No. 54-98805 (Japanese Patent Application No. 53-4855). 17 is a block diagram of a control device used to recreate a halftone cut along the contour. The signal L and the signal El are supplied to the comparator 11 which compares the two signals and outputs the control signal 15 to the selector 13. The signal R and the signal Er are supplied to the comparator 12 which compares the two signals and outputs the control signal 16 to the selector 14.

L 의 경우에는 신호(L)가 또 El<L 의 경우에는 신호(El)가 신호(L')로 출력된다.The signal L and the signal El are input to the selector 13, and either one of them is selected by the control signal 15 and output as the signal L '. That is, the signal L and the signal El are compared by the comparator 11, and El

In the case of L, the signal L is output, and in the case of El < L, the signal El is output as the signal L '.

R의 경우에는 신호(R)가 Er<R 의 경우에는 신호(Er)가 신호(R')로 출력된다. 신호(L')와 신호(R')는 2개의 연산회로(17),(18)에 병열로 입력한다.Similarly, the signal R and the signal Er are input to the comparator 14, and Er is controlled by the control signal 16.

In the case of R, when the signal R is Er <R, the signal Er is output as the signal R '. The signal L 'and the signal R' are inputted in parallel to the two calculation circuits 17 and 18.

"를 행하는 감산과 제산기로 구성되보있다.The calculating circuit 17 is an adder for performing "L '+ R'", and the calculating circuit 18

It is composed of a subtractor and a divider.

를 신호(P)로 항시 출력시키지만, 신호(L'+R')가 "-" 값인 경우에는 신호(W)를 출력시키지 않기 때문에 결과적으로는 아무것도 기록되지 않는다.The output signal L '+ R' of the arithmetic circuit 17 is divided into two and input to the gate 19 and the level detector 20. The level detector 20 detects the "+" or "-" level of the signal L '+ R', and operates to close the gate 19 only when this indicates a "-" value. Therefore, the gate 20 outputs the signal W when the signal L '+ R' is "+". On the other hand, the calculation circuit 18 is a signal

Is always output as a signal P, but when the signal L '+ R' is a value of "-", no signal W is output, resulting in nothing being recorded.

According to the obtained signals W and P, the frequency of the ultrasonic waves to be applied to the deflector shown in FIG. 1 is controlled so that the light beam is deflected by the deflector at an appropriate diffraction angle. Modifications can be made in various forms within the spirit of the invention. For example, the screen angle is not limited to only 0 degrees, 15 degrees, and 45, but the present invention can be applied to any other angle.

Claims (1)

An image signal obtained by scanning an original image is a method of controlling a light beam to be projected onto a photosensitive material in the horizontal and vertical directions as appropriate, and outputting the image signal in synchronization with scanning when a reproduced image is recorded to reproduce a mesh board image. Detects the position of the image outline in the image, compares the detected position of the outline with the width of the halftone region to be recorded, and exposes the inside of the outline of the halftone portion that the outline crosses to the light beam and is cut along the image outline. Syringe recording method of the mesh wood board image, characterized by regenerating the halftone.

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