JPS581598B2 - Display image correction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display image correction method for removing distortion of a display image of a display tube called an optical fiber tube.

Conventionally, in electrophotographic printing equipment or photoelectrostatic printing equipment, optical fiber tubes (hereinafter referred to as OFT) is often used.

For example, the OFT used in the electrophotographic printing apparatus has a structure in which an optical fiber plate (hereinafter referred to as OFF) is bonded to the display surface of a cathode ray tube (CRT), as shown schematically in Figure 1. and on the other hand,
Although not shown, the photoelectrostatic printing apparatus has a structure in which a discharge mechanism consisting of a photoconductor deposited film and a transparent electrode is provided in front of the OFF.

The OFF is a plate-shaped member formed by cutting a large number of optical fibers perpendicular to the bundle axis, and the back surface (
The image projected by the cathode ray tube (CRT) is transmitted through the surface (joint surface with the cathode ray tube surface) and is reproduced and imaged on the front surface.

Therefore, if all of the optical fibers are arranged precisely along parallel straight lines, the image reproduced on the OFF front surface will have a shape that matches the image projected on the back surface without any deformation. becomes.

However, at present, it is not only difficult and expensive to manufacture such a low-distortion OFF with extremely good parallelism of the optical fiber, but also it is difficult to manufacture this OFF with the current technology.
It is extremely difficult to reduce the deviation between the F back image and the front reproduced image to 50 microns or less.

As a result, when an OFF with such distortion is used for printing, the output characters or figures are distorted, making the printed output very difficult to see.

For example, as shown in the second figure, the paper PAP is placed on the OFF back side.
Short line segments 11, 121..., 16 in the transport direction of
is projected, and reproduced images Ll, L2,..., are displayed in front.
This is especially true when displaying L6 and repeatedly transferring and printing these onto paper PAP via a photoconductor drum and developer to obtain vertical lines K1, K2, . . . , K6. , the lines K2, K4, and K5 printed in the OFF-distorted portions become very unsightly.

In addition, as another example, as shown in Fig. 2b, OFT
When projecting a line segment 110 perpendicular to the transport direction of the paper PAP on the back side and displaying the reproduced image LIO on the front side, and transferring and printing these onto the paper PAP via the photoconductor drum and developer, the horizontal line segment 110 is K1o is printed in a curved manner at a distorted portion of the OFP.

Thus, the present invention aims to solve the above-mentioned drawbacks,
In the present invention, this purpose is to eliminate distortion of the image projected on the cathode ray tube surface by guiding it to an optical fiber plate connected to the cathode ray tube surface and converging on the exposed medium. In the correction method, an image tilting means for tilting the image projected on the cathode ray tube surface in various directions is provided, and the image tilting means preliminarily tilts the image in a direction opposite to the direction in which the image is tilted due to distortion of the optical fiber plate. This is achieved by tilting the screen and displaying it, and an embodiment thereof will be described in detail below with reference to the drawings.

FIG. 3 is a block diagram illustrating an OFT deflection circuit for implementing the present invention, FIG. 4 is a block diagram showing a part of this deflection circuit in detail, and FIG. 5 is a block diagram illustrating a part of this deflection circuit in detail. FIGS. 6 to 10 are time charts illustrating the waveforms of the signals Sa to Sn transmitted by each signal line, and FIGS. 6 to 10 are diagrams showing images on the CRT tube surface OFF front and paper surface when this deflection circuit is driven. It is.

In Figure 3, MDC is a horizontal main deflection coil that generates a magnetic field that deflects the electron beam in the longitudinal direction of the OFT tube surface, for example, in the horizontal direction, and XDC is a horizontal main deflection coil that similarly deflects the electron beam in the horizontal direction. Sub-deflection coil, Y
DC is a vertical deflection coil for vertically deflecting the electron beam.

The horizontal main deflection coil MDC is driven by a stepped signal Sa (see FIG. 5) generated in the main deflection section MD, and the signal Sa is applied to the character position designation section C under the control of the control section CNL.
It changes depending on the character position designation signal sent from the PG.

Therefore, one character, symbol, etc. is displayed at each step of the signal Sa, that is, at each non-change duration period.

On the other hand, the horizontal sub-deflection coil XDC is connected to the adder circuit ADDX.
One of the signals to be added, sb, is a horizontal sub-scanning signal consisting of a sawtooth wave whose period is one step, which is generated in the ice flat deflection section XD. , on the other hand, Sf is a correction signal generated by a correction section CMPX, which will be described later.

Further, the vertical deflection coil YDC is connected to an adder circuit ADDY.
One of the signals to be added, Sc, is 1/m of the one step generated in the vertical deflection section YD (m is the number of scanning lines per character).
A vertical scanning signal consisting of a sawtooth wave with one period of
This is a correction signal generated at Z.

Therefore, if the correction signal Sf. When Sj and Sm are not input to the adder circuits ADDX, ADDY, the CRT
On the (cathode ray tube) surface, the electron beam scans as indicated by the arrow in FIG. 6a, which is similar to known television scanning.

Also, in this case, the characters read from memory (“i”,
If the electron gun of the CRT is driven according to the pattern information of "mouth", "ha", etc.) and in synchronization with the screen scanning, as shown in FIG. 6a. Images of characters included in the pattern information are displayed on the screen.

When this image passes through the OFF and is projected onto the front of the OFF, the image is distorted and takes on a shape different from the character pattern.

For example, suppose that a part of the image is tilted due to OFF distortion, as shown in FIG. 6b.

Now, if a correction signal Sf is applied to the addition circuit ADDX, the tilted image as described above can be corrected to have the same shape as the character pattern, which will be explained in detail below.

FIG. 4a shows a correction section CMPX consisting of a circuit that generates the correction signal, and in the figure, CMPXG is an original correction signal generator AMPX1 that generates an original correction signal Se having a similar waveform to the vertical scanning signal Sc. ,AMPX2,...
, AMPXn are amplifiers with different amplification factors to which the original correction signal Se is input, SWX1, SWX2, . . .
..., SWXn is each amplifier AMPX1, AMPX2,
........., a group of switches for selectively sending out the output of AMPXn, Sd is the control section CNL
input from each switch SWX1, SWX2,...
..., a control signal that controls ON/OFF (opening/closing) of SWXn.

To describe the operation of the correction unit CMPX, the control signal Sd
The amplifiers AMPX1, AMPX2, etc.
・．． Select one amplifier whose amplification factor corresponds to the image inclination caused by OFP distortion at the character display position, and send out a correction signal Sf consisting of the original correction signal Se amplified by the selected amplifier. As you do,
The control signal Sd drives one of the switches SWX1, SWX2, . . . , SWXn connected to the selected amplifier to turn the switch on.

For example, when switch SWX1 is turned on, the original correction signal Se amplified by amplifier AMPX1 is sent out, and when switch SWX2 is turned on, amplifier AMPX
Similarly, when the switch SWXn is turned on, the original correction signal Se amplified by the amplifier AMPXn is sent out.

Then, this sent out correction signal Sf is sent to the adder circuit A.
It is added to the horizontal sub-scanning signal sb in DDX and applied to the horizontal sub-deflection coil XDC.

As a result, as shown in FIG. 7a, the upper part (terminus) of the scanning line on the CRT tube surface moves to the right (horizontal scanning direction) or to the left according to the sign of the amplification factor, and becomes tilted. .

Therefore, in the present invention, when scanning the display area of the OFT where the distortion that causes the image to be tilted as shown in FIG. It has become.

Then, as shown in FIG. 7b, the image projected on the front surface of the OFP substantially matches the image originally included in the pattern information because the inclination due to the OFF distortion and the inclination due to the scanning line are canceled out.

Next, suppose that a part of the image is tilted due to the OFF distortion and becomes as shown in FIG. 8b.

Now, if the correction signals Sj and Sm are added to the addition circuit ADDY, the tilted image as described above can be corrected to have the same shape as the character pattern, which will be explained in detail below.

FIG. 4b shows a correction unit CMPY consisting of a circuit that generates the correction signal, and in the figure, CMPYG is an original correction signal generation i that generates an original correction signal Si having a similar waveform to the vertical scanning signal sb, and AMPY1 ,AMPY2,...
, AMPYn are amplifiers with different amplification factors to which the original correction signal Si is input, SWY1, SWY2, . . .
..., SWYn is each amplifier AMPY1, AMPY2,
. . . , a switch group sh for selectively sending out the output of AMPYn is input from the control unit CNL and is connected to each switch SWY1, SWY2 . ......, SWY
This is a control signal that controls ON/OFF (opening/closing) of n.

To describe the operation of the correction unit CMPY, the control signal sh
Accordingly, the amplifiers AMPY1, AMPY2, . . .
・．． Among AMPYn, one amplifier whose amplification factor corresponds to the tilt of the image caused by the OFF distortion at the character display position is selected, and a correction signal Sj consisting of the original correction signal Si amplified by the selected amplifier is generated. so as to send out
The control signal sh drives any one of the switches swy1, SWY2, . . . , SWYn connected to the selected amplifier to turn the switch on.

For example, when the switch SWY1 is turned ON, the original correction signal Si amplified by the amplifier AMPY1 is sent, and when the switch SWY2 is turned ON, the original correction signal Si is sent to the amplifier AMPY1.
Similarly, when the switch SWYn is turned on, the original correction signal Si amplified by the amplifier AMPYn is sent out.

Then, this sent correction signal Sj is sent to the adder circuit A.
It is added to the vertical sub-scanning signal Sc at DDY and applied to the vertical sub-deflection coil YDC.

As a result, as shown in FIG. 9a, the right part (terminus) of the scanning line on the CRT tube surface moves upward (vertical scanning direction) or downward in accordance with the sign of the amplification factor and is tilted. Become.

Further, FIG. 4C shows a correction section CMPZ consisting of a circuit that generates the correction signal, and in the figure, CMPZG is an original correction signal generator AM that generates an output signal Sl of a constant level.
PZ1, AMPZ2, . . . , AMPZn are amplifiers with different amplification factors to which the original correction signal Sl is input, and SWZ1, SWZ2, . . . , SWZn are amplifiers AMPZ1, AMPZ, . A group of switches for selectively sending out the output of AMPZn, Sk is the control unit CN
Input from L and each switch SW1, SW2, ..., SW
This is a control signal that controls ON/OFF (opening/closing) of n.

To describe the operation of the correction unit CMPZa, the control signal Sk
The amplifier AMPZ1. AMPZ2,...,AM
The amplification factor on the back of PZn is OFF at the character display position.
The control signal selects one amplifier according to the amount of movement of the image from the reference position caused by the distortion, and sends out a correction signal Sm consisting of the original correction signal Sl amplified by the selected amplifier. Switches SWZ1, SWZ2 .Sk are connected to the selected amplifier. ……． By driving one of the SWZn switches, the switch is turned on.

For example, when switch SWZ1 is turned on, the original correction signal Sl amplified by amplifier AMPZ1 is sent out, and when switch SWZ2 is turned on, amplifier AMPZ
Similarly, when the switch SWZn is turned on, the original correction signal Sl amplified by the amplifier AMPZn is sent out.

Then, this sent correction signal Sm is sent to the adder circuit A.
At DDY, the horizontal sub-scanning signal Sc is enhanced and applied to the vertical sub-deflection coil YDC.

As a result, as shown in FIG. 9b, the scanning line on the CRT tube surface moves in parallel according to the sign of the amplification factor, and the image moves up and down.

(In FIG. 8b, the scanning line "C" is translated downward.

) As described above, in the present invention, when scanning the display area of the OFT where the distortion that causes the image to be tilted as shown in FIG. By tilting in the opposite direction to the image tilt, the image projected on the front surface of the OFF almost matches the image originally contained in the pattern information, since the tilt due to the distortion of the OFF and the tilt due to the scanning line are canceled out.

If the scanning line is tilted in this way to project the image on the OFF back surface and transfer printing is performed on the paper via the photoconductor drum and developer, the unsightly printing results obtained in the conventional method can be avoided. .

For example, as shown in FIG.
, Ki2', ..., K6' on paper PAP, line segments 11', 12', ... to be projected on the back of OFP
By tilting ..., 16', line segment images L1', L2', ..., which are reproduced without inclination on the OFF front surface
Since L6 is obtained, the vertical lines K1', K2',...
. . , K6' provides a continuous, smooth and easy-to-see printing result.

By the way, an example of a specific method of generating the control signal Sd for changing the slope of the scanning line will be described as follows.

First, the direction and amount of image inclination due to OFF distortion for each display position are measured, and the direction and amount of inclination of the scanning line, ie, the amount of correction, are determined.

Then, the correction signal Sf according to this correction amount is converted into the original correction signal S.
Find the amplification factor of the amplifier necessary to obtain from e, select an amplifier having this amplification factor from the amplification factors AMPX1, AMPX2, ..., AMPXn, and select the switch connected to this amplifier from the switch group SWX1. ．． SWX2
,……． SWXn, please.

Thereafter, the obtained switch and the display device are stored in correspondence with each other in the control unit CNL, and the correspondence is made according to the display position indicated by the character position designation signal generated from the character position designation unit CPG. A control signal Sd is sent from the control unit CNL to drive the switch.

In this way, the amplifier MPX1. AMPX2,……. A
The number of MPXnOs can be reduced.

Of course, in the present invention, in addition to the above embodiments, amplifiers AMPX1, AMPX2, ..., AMPXn and switches SWX1, SWX2, ..., SWXn are provided in the same number as the display positions to be corrected, and The correction signal Sf can also be generated by selecting an amplifier corresponding to .

Sj and Sn can also occur in the same way as Sf.

As can be seen from the above description, according to the present invention, it is possible to eliminate the unsightly print results that have conventionally occurred, and it is possible to dramatically improve the print quality.

[Brief explanation of drawings]

Figure 1 is an external view of the optical fiber tube.
Figure 2 shows the conventional printing results without correction;
4 and 4 are diagrams showing a circuit for implementing the present invention, and FIG. 5 is a time chart illustrating each signal in this circuit,
6 and 8 are diagrams showing the cathode ray tube surface and the front surface of the optical fiber plate when the correction section of this circuit is not operating, and FIGS. 7 and 9 are diagrams showing each of the above-mentioned screens when this correction section is operating. , and FIG. 10 are diagrams illustrating printing results when the present invention is implemented. OFT...Optical fiber tube, CRT...Cathode ray tube, OFP...
Optical fiber plate, PAP...
・Paper, XD...Horizontal sub-deflection section, YD...
・Vertical deflection section, CMPX, CMPY, CMPZ...
...Correction section, ADDX. ADDY...Addition circuit, cMPXG...Original correction signal generator, (AMP
X1, AMPY1, MMPZ1). (AMPX2.AM
PY2, AMPZ2), ... (AMPXn.AM
PYn. AMPZn)...Amplifier, (SWX1.SWY
1, SWZ1), (SWX2, SWY2, SWZ2),
......(SWXn, SWYn.SWZn)...
...Switch, Sf. Sj. Sm...Correction signal.

Claims (1)

[Claims] 1. In a display image correction method in which an image projected on a cathode ray tube surface is guided by an optical fiber plate connected to the cathode ray tube surface and focused on an exposed medium, distortion of the image is removed. An image tilting means is provided for dividing an image projected onto a plurality of parts into a plurality of parts, tilting the scanning direction of a scanning line for each divided unit, and tilting the image for each divided unit, and using the image tilting means to tilt the scanning direction of the scanning line for each divided unit. - A display image correction method characterized by displaying an image tilted in advance in the opposite direction to the direction in which it is tilted due to distortion of the fiber plate.