KR20030010809A - Correction method of geometric distortion using digital dynamic convergence control formula - Google Patents

Abstract

PURPOSE: A method of correcting geometric distortion using digital convergence controller is provided to correct geometric distortion as well as mis-convergence to improve picture quality of a CRT. CONSTITUTION: A plurality of image positions are extracted from an image display area of a CRT. Data storage addresses of a data storage device are mapped with the extracted image positions. Mis-convergence of the extracted image positions is measured. Correction data for the mis-convergence is generated. The mis-convergence correction data is stored in the mapped data storage addresses. Mis-convergence in each image position is independently corrected based on the data stored in the data storage device. In the case where geometric distortion of a picture is removed, four outer boundary lines of top, bottom, left and right of the cross hatch pattern image of G beam are moved to desired positions to correct the distortion in the straight form. Mis-convergence with respect to R beam and B beam is corrected by a digital dynamic convergence controller using a convergence yoke coil.

Description

Geometric method of geometric distortion using digital dynamic convergence control formula

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital dynamic convergence controller, and more particularly, to a geometric distortion correction method using a digital convergence correction method that can improve not only miss convergence but also geometric distortion.

In general, a deflection yoke (DY) in a CRT imager performs a function of deflecting R, G, and B electron beams to reach a desired position on a screen. As the screen becomes more precise, it is not possible to achieve the desired convergence performance of the screen with the deflection yoke alone. Therefore, it is common to mount various correction devices on the deflection yoke.

Among them, magnetic pole adjustment coils of Convergence Purity Magnet (CPM) operation principle are attached to the neck of deflection yoke to move the R, B beam relative to G beam. Dynamic Convergence Controllers, which dynamically adjust the convergence state of the screen, are widely used.

In particular, in accordance with the advent of digital TV broadcasting, it is essential to apply a dynamic convergence correction device to implement a high definition screen at the HDTV level for text information transmission and graphic processing.

The circuit of the conventional dynamic convergence compensator for deflection yoke described above is composed of a plurality of resistors, inductors, capacitors, diodes, and the like. It is a method to correct the convergence error of the screen by adjusting.

With this type of adjustment circuit, only a current waveform of a predetermined type can be applied to the magnetic field adjustment coil, and therefore, there is a technical limitation that only a limited number of convergence errors are corrected. In addition, when the miss convergence error of one region of the screen is corrected, the miss convergence error of the other region is also changed in response so that it is very difficult to correct all the miss convergence errors of the entire screen.

In addition, the operator visually checks the degree of convergence error and empirically adjusts and adjusts the adjustment means appropriately based on this. Thus, in the conventional method, the screen convergence is desired for a large screen, a full plane, and an ultra wide-angle CRT imager. It is almost impossible to match with.

Therefore, in the conventional method described above, a method proposed to overcome the limitations of the method of measuring the degree of error of convergence with the naked eye of a worker is a display device such as a color CRT, a liquid crystal display (LCD), or a color plasma display panel (PDP). A display characteristic measuring apparatus for measuring display characteristics such as convergence of is proposed.

This display characteristic measuring apparatus is configured to capture an image of each color component of an image of each color component of R (red) G (green) B (blue). An image processing apparatus which performs predetermined processing after the processing, and a display apparatus which displays the measurement result.

For example, as shown in Japanese Patent Application Laid-Open No. 8 (1996) -307898, the convergence measuring device displays a predetermined white measurement pattern displayed on a color CRT to be measured by a camera equipped with a color gamut sensor such as a CCD. During image pick-up, the luminance center of each picked-up image of each color component R, G, and B is calculated during image processing, and the relative displacement of this luminance center is displayed in the amount of miss convergence.

Therefore, the misconvergence measuring device calculates the light emission position (light emission center position) of the measurement pattern of each color component on the display surface of the color CRT measured by the measurement pattern image formation position (luminance center position) of each color component on the imaging surface of the color camera. The relative variation in the light emission position of each color component is calculated.

However, this technique is calibrated using a special calibration chart before measurement as shown in the accompanying FIG. 1 due to its own problems, that is, the measurement accuracy easily changes with changes in temperature and humidity.

The calibration method shown in FIG. 1 includes a calibration chart 103 (chart with a cross hatching pattern 105 drawn on an opaque white plate) illuminated by a fluorescent lamp 104. The imaging device 101 of the convergence measuring device 100 is shown in FIG. Correction data indicating the relative positional relationship of each area sensor is calculated using the captured image. The calculated calibration data is stored in a memory in the apparatus main body 102 and used as data for correcting the shift of the luminance center position of each color component measurement pattern at the time of convergence measurement.

According to the conventional method for correcting the relative variation of the area sensor, the position (absolute position) of each area sensor in the reference coordinate system in the convergence measurement system is determined by using respective color component image data obtained by photographing a special calibration chart. The relative variation of the area sensor is calculated by this calculation result. As a result, many computational parameters (parameters) increase, which requires a lot of computational time.

Moreover, because a special calibration chart is used rather than the measurement pattern displayed on the CRT to be measured, a problem arises that it is inconvenient and difficult to calibrate the convergence measurement system in the production line.

A recent technique proposed to overcome the above-mentioned problems is a technique described in Korean Patent Laid-Open No. 1999-013780, which is an apparatus for automatically measuring convergence of color CRT shown in FIG.

1 is a schematic configuration diagram of a convergence measuring device 1 of a color CRT, the convergence measuring device 1 including an imaging device 2 and a measuring device 3.

The imaging device 2 captures a predetermined measurement pattern (e.g., cross hatching pattern, dot pattern, etc.) displayed on the display surface of the color display 4 to be measured, and detects an image by stereoscopic vision. A pair of imaging cameras 21 and 22 are provided.

The measuring device 3 calculates the miss convergence amount of the color display 4 using the image data of the measurement pattern obtained by the imaging device 2, and displays the result of the calculation on the display device 36.

The imaging camera 21 in the imaging device 2 is provided with a dichroic prism 212 that decomposes light into three colors behind the imaging lens 211, and the respective colors R, G, and B rays appear. A solid-state image pickup device 213R, 213G, or 213B including a CCD area sensor is disposed at a position facing the exit surface of the dichroic prism 212, and is a three-plate type color image pickup device. The imaging camera 22 is also a three-plate color imaging device similar to the imaging camera 21.

The imaging camera 21 has an imaging controller 214 for controlling the operation of each of the solid state imaging elements (hereinafter referred to as CCD) 213R, 213G, and 213B, and the imaging lens 211 to be driven automatically. The focus control circuit 215 which adjusts the focus by the camera and the signal processing circuit 216 which performs predetermined image processing on the image signals transmitted from the CCDs 213R, 213G and 213B and outputs them to the measuring device 3 It is installed. In this manner, the imaging controller 224, the focus control circuit 225, and the signal processing circuit 226 are provided in the imaging camera 22.

The imaging controller 214 is controlled by an imaging control signal sent from the measuring apparatus 3, and controls the imaging operation (charge accumulation operation) of the CCDs 213R, 213G, and 213B by this imaging control signal. The imaging control device 224 is controlled by an imaging control signal sent from the measuring device 3, and controls the imaging operation of the CCDs 213R, 213G, and 213B by this imaging control signal.

The focus control circuit 215 is controlled by the focus control signal sent out from the measuring device 3 and drives the front group 211A of the imaging lens 211 by this focus control signal, thereby displaying the color display 4. The optical image of the measurement pattern displayed on the surface is imaged on the imaging surface of CCD (213R, 213G, 213B).

Similarly, the focus control circuit 225 is controlled by the focus control signal transmitted from the measuring device 3, and drives the front group 221A of the imaging lens 221 by the focus control signal, thereby displaying the color display. The optical image of the measurement pattern displayed on the display surface of (4) is imaged on the imaging surface of CCD (213R, 213G, 213B).

Focus control is performed by a signal from the controller 33, for example, by a climbing method. Specifically, for example, in the case of the imaging camera 21, the control unit 33 extracts the green image high frequency component (end of the measurement pattern) picked up by the CCD 213G so that the high frequency component is maximized (of the measurement pattern). The focus control signal is output to the focus control circuit 215 so that the end is clearer.

The focus control circuit 215 moves the front and rear groups 211A of the imaging lens 211 forward and backward to reduce the distance of movement gradually in accordance with the focus control signal so as to reduce the moving distance. Finally it is set.

Focus control is performed using the image picked up in this embodiment. However, for example, the imaging cameras 21 and 22 are provided with distance sensors, and the imaging lenses 211 and 221 are display surfaces of the imaging cameras 21 and 22 and the color display 4 detected by the distance sensors. Can be driven using distance data between.

The measuring device 3 comprises analog / digital (A / D) converters 31A and 31B, image memories 32A and 32B, a control unit 33, a data input device 34, a data output device 35 and a display. Device 36.

The A / D converters 31A and 31B convert image signals (analog signals) input from the imaging cameras 21 and 22 into image data in the form of digital signals. The image memories 32A and 32B store image data output from the A / D converters 31A and 31B, respectively.

Each of the A / D converters 31A and 31B is provided with three A / D conversion circuits corresponding to the image signals of the respective color components R, G, and B. Each of the image memories 32A, 32B includes three frame memories corresponding to the respective color components R, G, and B.

The control unit 33 is an operation control circuit including a microcomputer and is provided with a memory 331 including a read only memory (ROM) and a memory 332 including a random access memory (RAM).

The memory 331 stores a program that performs convergence measurement processing (including a series of operations including driving of an optical system, imaging, calculation of image data, etc.) and data necessary for the calculation (correction values, data conversion tables, etc.) have. The memory 332 also provides a data area and a work area for performing various operations to make convergence measurements.

The miss convergence amount (measurement result) calculated by the control unit 33 is stored in the memory 332, output to the display device 36, and displayed in a predetermined display format. The miss convergence amount is also output to an externally connected device (printer, or external storage device) through the data output device 35.

The data input device 34 operates to input various data for the convergence measurement and includes, for example, a keyboard. The data input device 34 inputs data such as measurement point positions on the display surface of the pixel array pitch color display 4 of the CCDs 213 and 223.

The color display 4 to be measured includes a color CRT 4 for displaying a video image and a drive control circuit 42 for controlling the driving of the color CRT. The video signal of the measurement pattern generated by the pattern generator 5 is input to the drive control circuit 42 of the color display 4, which in turn drives the deflection circuit of the color CRT 41 by means of the video signal to the display surface. For example, the cross hatching measurement pattern is displayed as displayed in FIG. 3.

In this convergence measuring device 1, the measurement pattern images displayed on the color display 4 are stereoscopically picked up by the imaging cameras 21 and 22 of the imaging device 2, and the amount of miss convergence is increased. It is measured using the image data obtained by step (22).

That is, the accompanying FIG. 3 is a diagram showing the cross hatching pattern 6 displayed on the color CRT 41, and the cross hatching pattern 6 is made by crossing a plurality of vertical lines and a plurality of horizontal lines. The display surface 41a of the color CRT 41 is displayed in a suitable size so that a plurality of intersection points are included. The miss convergence amount measuring regions A (1) to A (n) are set at arbitrary positions in the display surface 41a to have at least one intersection point.

In each measurement area A (r) (r = 1, 2, ... n), the image of the vertical line in which the horizontal (X direction in the XY coordinate system) miss convergence amount ΔDX is included in this measurement area A (r) The image is calculated by the image, and the vertical (Y-direction in the XY coordinate system) miss convergence amount ΔDY is calculated by the captured image of the horizontal line.

Even if accurate data on miss convergence is secured by the recent technology as described above, the object of controlling the convergence is ultimately limited to the deflection yoke, so that the error of the overall convergence can be adjusted when adjusting the deflection yoke. The fundamental problem is that only some areas of convergence cannot be adjusted independently.

That is, it is common to adjust the convergence of one part so that the convergence of the other part related to it is also changed, so that the correction of the miss convergence to the most optimal state as a whole is performed.

In particular, in the high-definition screen such as HDTV, the difficulty is more serious.

As a digital dynamic convergence correction method as shown in FIG. 4 attached to the recent technology proposed to solve such a problem, the configuration and operation of the main part thereof, A control unit comprising a first address selector referred to as reference number 12A, an EEPROM referred to as reference number 13A, a storage unit comprising first and second RAMs referred to as reference numbers 13C and 13D, and reference numbers 14, 15A and 15B. Extraction address generation unit referred to as " 15C, 16 ", output unit referred to as 17, 17A, 18, and 19, vertical section scan line counter referred to as 20, and multiplier and reference number 21. And a correction data interpolation section comprising a sign bit reader referred to as 22, an adder 23, a subtractor 24, and a data selector 25.

First, the microcontroller 11 receives a correction data, interpolation data and a control command signal from an external source to create a recording address to be stored in a memory.

Here, the interpolation data includes a difference between the correction data of each correction data and the control data positioned immediately below each of the screen control points defined as the intersections in the cross hatch pattern screen illustrated in FIG. 5 in one vertical section. It is a value divided by the dividing number NIL of the third divider, which is the number of horizontal scan lines, and corresponds to an increment value of correction data to be increased or decreased as the horizontal scan lines increase in one vertical section.

At this time, when the completion signal is OFF with the control command signal, the microcontroller 11 operates the address selector 12 with the control signal AS, so that the recording address outputted from the microcontroller 11 is the first RAM 13C and the control signal. After the address bus is connected to be delivered to the address port of the second RAM 13D, correction data is stored in the first RAM 13C, and interpolation data is stored in the second RAM. Thereafter, when the completion signal is in the ON state, the correction data and the interpolation data are stored in an EEPROM referred to by reference number 13A.

When the OFF state in the open loop mode is received as the mode signal, the microcontroller 11 reads the correction data and interpolation data stored in the EEPROM 13A and records them in the corresponding RAMs 13C and 13D, respectively.

Subsequently, when both correction data and interpolation data are recorded and stored in the RAMs 13C and 13D, the control signal AS is generated to extract the address of the address generator 16 to the addresses of the first RAM 13C and the second RAM 13D. The address selector 12 is operated to be simultaneously transmitted to the bus, and both the first and second RAMs 13C and 13D are put into a read state by a read enable signal.

At this time, the extraction address generation unit referred to 14 to 16 receives the horizontal and vertical synchronization signal and outputs the extraction address of the correction data and the interpolation data stored in the first and second RAM in synchronization with the scanning time of each screen control point The extracted address is simultaneously transmitted to the address ports of the first and second RAMs 13C and 13D via the address selector 12.

Thereafter, the interpolation unit uses the correction data and the interpolation data simultaneously output from the first and second RAMs 13C and 13D according to the memory extraction address of the extraction address generator to count the horizontal scan line numbers within a vertical section. Interpolate correction data according to

At this time, the vertical section scan line counter 20 in FIG. 4 receives a horizontal synchronization signal as a clock signal and counters it, and receives a vertical address signal as a clock signal and initializes the counter to output a horizontal scan line number scanned within one vertical section. .

The horizontal scan line number data output from the vertical section scan line counter 20 is multiplied by the interpolation data output from the second RAM 13D by the multiplier 21 and converted into increment values for correction data to be converted into a code bit reader 22. It is input to the adder and subtractor via.

In addition, the adder and the subtractor output a value obtained by adding or subtracting the increase / decrease value to the correction data of the first RAM 13C, which is always input at a constant value within one vertical section, which in turn corrects the correction data within one vertical section. Linear interpolation in the vertical direction.

In addition, the code bit reader 22 operates the data selector 25 to select an adder or a subtractor output in accordance with the read state of the code bit. Accordingly, linearly interpolated correction data corresponding to the horizontal scan line being scanned is The output is delivered.

In this case, the converged yoke used has an 8-pole structure, as shown in FIG. 6, and eight poles are used in appropriate combination as shown in FIGS. 7A to 7F. Four- and six-pole magnetic fields in each horizontal and vertical direction are used to correct the convergence error, and two-pole magnetic fields in each horizontal and vertical direction are used to correct the geometric distortion.

Therefore, the geometric distortion correction method used in the conventional digital convergence correction device operating as described above is applied to the horizontal and vertical two-pole converged yoke coils by applying a voltage waveform in the form of a parabolic or cubic polynomial curve passing through the waveform generator. Although the raster may be corrected, the conventional method described above may be effective for correcting geometric distortions in the form of upper, lower, left and right pins as shown in FIG.

As shown in the accompanying FIG. 9, the limitation of the inner pin-cushion geometry distortion and linearity of the E / W direction is not shown.

That is, in general, the geometric distortion in the E / W direction is mainly corrected by a correction circuit inside the SET of the CRT display apparatus in addition to the deflection yoke, but as shown in FIG. requester (raster) and outlines are referred to "E / W inner pin-Cushion geometric why" that has a why in the internal vertical line to pin shape in the corrected state in a straight line, which ΔD _i as shown in FIG accompanying 9 Indicates this.

In addition, the beam must be linearly proportional to the strength of the deflection current supplied to the horizontal deflection coil of the deflection yoke, and the E / W linearity indicates its proportion. That is, as shown in FIG. 9, beam deflections D1 and D2 of the ⅓T _H and ⅔T _H dices should be coincident with ⅓D3 and ⅔D3 respectively, and the degree of deviation may be defined as a linearity error.

Therefore, the geometric distortion correction method used in the conventional digital convergence correction device is applied to the horizontal and vertical two-pole convergence yoke coils by applying a voltage waveform in the form of a parabolic or cubic polynomial curve passing through the waveform generator. It is because of the above problem.

An object of the present invention to solve the problems described above is to use a digital copper convergence controller to correct not only miss convergence but also geometric distortion (E / W Inner Pin-Cushion) geometric distortion in the CRT screen. It is to provide a geometric distortion correction method using a digital convergence correction method to improve the quality.

1 is an exemplary diagram of a measurement apparatus for generating a conventional automatic miss convergence correction value;

2 is an illustration of an improved miss convergence measurement apparatus of the technique shown in FIG.

3 is an exemplary diagram of an image pattern for applying the technique illustrated in FIG. 2;

4 is an exemplary configuration diagram of a digital copper convergence correction apparatus proposed recently;

5 is an exemplary diagram of a cloth hatch pattern used in the digital copper convergence correcting apparatus shown in FIG. 4;

6 is an exemplary configuration diagram of an 8-pole converged yoke commonly used.

7A to 7F are exemplary views showing operating characteristics for dynamic convergence correction using the convergence yoke illustrated in FIG. 6;

8 is an example of geometric distortion in the form of up, down, left and right fins,

9 is an example of geometric distortion of a Gull Wing type,

FIG. 10 is a diagram illustrating an example of main components of a part used in the present invention in the configuration of FIG.

11 is an exemplary view of an automated surface correction system using a digital dynamic convergence controller,

12 is an illustration of geometric distortion correction point measurements for performing digital convergence correction in accordance with the present invention.

The geometric distortion correction method using the digital convergence correction method according to the present invention for achieving the above object comprises the steps of: extracting a plurality of screen positions in the screen display area of the CRT image device; A second process of mapping a data storage address provided in an arbitrary data storage means and a plurality of screen positions extracted through the first process; A third step of measuring a degree of convergence error at each screen position extracted through the first step; A fourth step of generating correction data for a convergence error at each screen position measured in the third step; A fifth process of storing miss convergence correction data at each screen position generated in the fourth process at a data storage address mapped through the second process; A sixth step of individually performing correction for convergence errors at each screen position according to scanning of the electron beam when displaying an image based on data stored in any data storage means through the fifth step; In case of removing geometric distortion of the screen, the upper, lower, left, and right edges of the G-beam cross hatch pattern screen are moved to a desired position and corrected in a straight line using the average of each measured value. The B-beam includes a seventh process of adjusting the position of the G-beam because the miss-convergence is corrected by the digital converging controller using the converged yoke coil having a plurality of poles.

An additional feature of the geometric distortion correction method using the digital convergence correction method according to the present invention for achieving the above object is that the two poles, four poles or the like is commonly used for dynamic convergence correction It is used as an adjustment signal for a magnetic pole adjustment coil of six-pole structure.

As another additional feature of the geometric distortion correction method using the digital convergence correction method according to the present invention for achieving the above object, the seventh step is to set the center point of the screen to match the actual physical center of the CRT A first step of doing; A second step of respectively defined as -⅓T _{H, H} -⅔T, ⅓T _{H, H} ⅔T the desired location for each scanning position in the horizontal direction of the cross-hatch pattern and the screen; A third step of defining a position error associated with the geometric distortion of each of the correction points corresponding to the point defined in the second step as shown in the following equation; And

A fourth step of applying a correction voltage of the proportional integral control method to the horizontal and vertical two-pole converged yoke coils from the positional error obtained through the third step in a feedback control method as defined below;

It is to include.

The above object and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention described below with reference to the accompanying drawings by those skilled in the art.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 10 is a block diagram showing the structure of the digital dynamic convergence controller according to the present invention as a partial configuration example corresponding to the main part of the present invention as a part of the configuration shown in FIG.

In FIG. 10, the digital convergence controller receives correction data given from an external control computer, stores the correction data in a memory according to a predetermined recording address, and then inputs horizontal and vertical synchronization signals obtained from an image signal received by the CRT imager. It generates the extraction address, reads the correction data stored in the memory according to the extraction address, converts and amplifies the control voltage or control current, and drives the converged yoke coil.

Here, the correction data are voltage values or current values to be applied to each of the two-pole, four-pole, and six-pole converged yoke coils for correction points defined as respective intersection points on the screen of the cross hatch pattern as shown in FIG. Appropriately calculated from the screen convergence error measured by the measuring device, it is transmitted to the serial digital convergence controller through serial communication such as RS-232C.

In addition, the correction data transmitted to the digital synchronization controller is stored in the memory according to a recording address of a predetermined rule via a microcontroller (MCU), and when the storage is completed, the address generator generates a horizontal and vertical synchronization signal. The memory extraction address is generated according to the scanning time of the screen correction point so that the correction data stored in the memory is output.

At this time, the recording address and the extraction address are configured by combining the horizontal position number, the vertical position number, and the convergence yoke coil number of each correction point, and through this, individual access and adjustment of the convergence of each correction point is possible.

In this way, the convergence can be adjusted independently for each of the correction points shown in FIG. 5. That is, a method of controlling the current amount of each of the two-pole, four-pole, and six-pole converged yoke coils at the positions of the respective screen correction points of FIG. 5, and the operation of the converged yoke coils described in FIGS. 7A to 7F. It can be seen from the principle that the convergence of the R, G, and B beams can be adjusted to an arbitrary state.

Subsequently, the automated surface correction system as shown in FIG. 11 is a closed loop control structure, and repeatedly performs the above-described correction process several times to achieve the desired convergence performance. The combination indicated by the dotted line in FIG. 11 is stored in the EEPROM of the product and functions as a separate product.

In this process, the control computer performs a function of generating correction data using an appropriate control method from the screen convergence state obtained through the image measuring apparatus. Then, when power is supplied, the digital dynamic convergence controller reads the correction data stored in the EEPROM and operates as an open loop control structure to correct the screen convergence error.

The present invention proposes a new method for correcting the inner pin-cushion geometry distortion and linearity error in the E / W direction by using a horizontal two-pole convergence yoke coil in using the digital dynamic convergence controller.

First, the image measuring device measures the relative position of each correction point with respect to the screen center point in the G-beam cross hatch pattern. 12 diagrammatically illustrates this measurement state. At this time, to remove the geometric distortion of the screen, move the position of the G beam at each correction point to a desired position on the screen and correct it in a straight line. The R beam and the B beam use 4-pole and 6-pole converged yoke coils. Therefore, the misconvergence is corrected by the digital co-convergence controller, so that the G-beam is positioned.

At this time, the center point of the screen should be coincident with the actual physical center of the CRT. This can be easily achieved by using a means such as a bipolar convergence mark net.

First, the geometric distortion of the raster outer boundary line in the E / W direction is corrected linearly by the correction circuit inside the set. At this time, since the raster boundary lines on the left and right sides cannot be correctly corrected in a straight line, the deflection position is set to an average value of the measurement points existing on the boundary line, which is expressed as Equation 1 below.

(Equation 1)

Thus, a measure of the relative position with respect to the center point G of the beam at each of the correction points in the scanning position in the horizontal direction indicated in the accompanying Figure 12 -⅓T _{H, H} -⅔T, ⅓T _{H, H} ⅔T Next, the The position error is defined as defined in Equation 2 below.

(Equation 2)

The correction voltage of the proportional integral control method (Equation 3 below) is applied to the horizontal two-pole converged yoke coil from the positional error calculated by the equations (1) and (2) in the feedback control as follows.

(Equation 3)

Here, the superscript (n) in Equation 3 means the n-th state in the feedback control in FIG. The control parameters of the proportional integral control method may be appropriately set empirically in consideration of stability.

Normally proportional control constant Is set to the inverse of the sensitivity of the horizontal and vertical two-pole converged yoke coils, and the integral control constant Is set to 0.5 times each proportional control constant.

By repeating the feedback control using the above proportional integral control several times, the final correction voltages to be applied to the horizontal and vertical two-pole convergence yoke coils are obtained for each correction point, and as a result, the G beam position of each correction point is displayed. The geometric distortion is corrected by moving to the desired position given with respect to the center point.

The R and B beams can also control 4-pole and 6-pole converged yoke coils to match the position of the G-beams. Set the time constant L / R so that the current response of the converged yoke coil appears in a straight line by connecting a resistor in series to the converged yoke coil in the horizontal direction on the screen. You can interpolate. In the section between the correction points in the vertical direction, as shown in FIG. 10, the second RAM 13D, the vertical section scan line counter 20, the multiplier 21, the adder 23, and the subtractor 24 of the digital dynamic convergence controller are connected. Linear interpolation can be used.

Through the proposed method as described above, it can be seen that any type of geometric distortion, such as "E / W Inner Pin-Cushion Geometric Distortion", which is difficult to correct by the conventional waveform generation method, can be corrected.

While the invention has been shown and described in connection with specific embodiments thereof, it is well known in the art that various modifications and changes can be made without departing from the spirit and scope of the invention as indicated by the claims. Anyone who owns it can easily find out.

If the geometric distortion correction method using the digital convergence correction method according to the present invention as described above is provided, the proposed method after mounting a horizontal, vertical two-pole convergence yoke coil in the prior art digital dynamic convergence controller (DDCC) By adjusting the correction voltage and driving the converged yoke coil, any geometric distortion of all types can be corrected. Therefore, a high quality screen can be obtained by correcting not only convergence but also geometric distortion with a digital dynamic convergence controller.

Claims (3)

Extracting a plurality of screen positions from the screen display area of the CRT image device; A second process of mapping a data storage address provided in an arbitrary data storage means and a plurality of screen positions extracted through the first process; A third step of measuring a degree of convergence error at each screen position extracted through the first step; A fourth step of generating correction data for a convergence error at each screen position measured in the third step; A fifth process of storing miss convergence correction data at each screen position generated in the fourth process at a data storage address mapped through the second process; A sixth step of individually performing correction for convergence errors at each screen position according to scanning of the electron beam when displaying an image based on data stored in any data storage means through the fifth step; And When removing the geometric distortion of the screen, move the top, bottom, left, and right borders of the G-beam cross hatch pattern screen to the desired position and correct it in a straight line using the average of each measured value. The beam has a geometrical distortion using a digital convergence correction method comprising a seventh step of adjusting the position of the G beam because the miss-convergence is corrected by the digital dynamic convergence controller using a converged yoke coil having a plurality of poles. Correction method. The method of claim 1, The miss convergence correction data is a geometric distortion correction method using a digital convergence correction method, characterized in that the adjustment signal of the magnetic field adjustment coil of the 2-pole, 4-pole or 6-pole structure generally used for dynamic convergence correction. The method of claim 1, The seventh step includes a first step of setting the center point of the screen to coincide with the actual physical center of the CRT; A second step of respectively defined as -⅓T _{H, H} -⅔T, ⅓T _{H, H} ⅔T the desired location for each scanning position in the horizontal direction of the cross-hatch pattern and the screen; A third step of defining a position error associated with the geometric distortion of each of the correction points corresponding to the point defined in the second step as shown in the following equation; And A fourth step of applying the correction voltage of the proportional integral control method to the horizontal and vertical two-pole converged yoke coils from the positional error obtained through the third step in a feedback control manner as defined below; Geometric distortion correction method using a digital convergence correction method, characterized in that it comprises a.