JPH05300528A - Digital convergence correcting device - Google Patents

Abstract

PURPOSE:To provide a digital convergence correcting device which can automatically correct the convergence and the image distortions. CONSTITUTION:A detector 1 which detects the misconvergence quantities a1-a9 and b1-b9 produced at the points P1-P9 set previously on a screen and an arithmetic RAM 5 calculates the coefficients k1-k9 of each term of a correction formula expressed in a two-dimensional higher order function from those extents a1-a9 and b1-b9 detected by the detector 1, are provided. Thus the coefficients k1-k9 are obtained by the RAM 5 and the misconvergence can be automatically corrected based on those coefficients.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color television convergence correction apparatus for correcting the distortion of an image appearing on the screen of a video projector or a color television.

[0002]

2. Description of the Related Art In a picture tube of a color television using a shadow mask type three-electron gun or a color video projector which has become widespread in recent years, since there are three electron streams, these electron beams are focused on a fluorescent screen. A convergence correction circuit is required to display a distortion-free image.

FIG. 6 shows, for example, NEC Corporate Bulletin Vol. 43 No. 4/19.
FIG. 90 is a block diagram in which the configuration of the conventional digital convergence correction device disclosed in “Hi-Vision Projector” is rewritten so as to be suitable for the description of the present invention to be described later.

In FIG. 6, reference numeral 3 is a microprocessor, 4 is a waveform parameter ROM, 5 is a calculation RAM, and 6
Is a correction data memory, 7 is a PLL timing generator, 8 is a vertical interpolation calculation circuit, and 9 is a D / A converter.

The operation of the conventional digital convergence correction device shown in FIG. 6 is as follows. For example, when a keyboard switch or the like (not shown) is operated, a control signal is input to the control terminal 30 accordingly. When this control signal is input, the microprocessor 3 receives, for example, FIG.
Basic waveform parameters such as a sawtooth wave and a parabolic wave shown in FIG. 3 (b) are read from the waveform parameter ROM 4 and adjustment levels are set, and these basic waveforms are combined in the arithmetic RAM 5. The desired correction waveform data thus obtained is stored in the correction data memory 6.

Further, a horizontal synchronization signal and a vertical synchronization signal are input to the PLL timing generator 7, and a control signal necessary for synchronizing each correction point and data is generated according to these signals. A known vertical interpolation arithmetic circuit 8 interpolates the correction points in the vertical direction with respect to the data stored in the correction data memory 6, and the D / A converter 9 converts the result into an analog signal. After passing through a low-pass filter (not shown), it is passed through the correction coil as a convergence correction current. As a result, the direction of the electron beam is corrected, the convergence on the screen is corrected, and an image without distortion is obtained.

In the conventional digital convergence correction device, the engineer visually detects the image distortion as described above and sensually detects the image distortion, and manually operates an adjusting means such as a keyboard to eliminate the distortion. Convergence correction is performed by generating a desired correction waveform.

[0008]

Since the conventional digital convergence correction device is constructed as described above, the engineer needs to perform the adjustment while visually observing the screen, which requires manpower and the adjustment for the adjustment. There is a problem that time is required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a digital convergence correction apparatus capable of automatically correcting convergence and image distortion.

[0010]

A digital convergence correction apparatus according to the present invention includes a detector for detecting the amount of misconvergence at a predetermined set point on the screen, and the amount of misconvergence detected by this detector. To RAM for calculating the coefficient of each term of the correction formula represented by the binary higher-order function.

[0011]

In the digital convergence correction apparatus of the present invention, the coefficient of each term of the correction equation represented by the binary higher-order function is calculated by the calculation RAM according to the misconvergence amount at each set point on the screen detected by the detector. Then, the misconvergence correction is automatically performed according to the obtained result.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments.

FIG. 1 is a block diagram showing the configuration of an embodiment of a digital convergence correction apparatus according to the present invention. In FIG. 1, the same reference numerals as those in FIG. 6 referred to in the above description of the conventional example indicate the same or corresponding portions.

In FIG. 1, reference numeral 1 is a detector as a misconvergence amount detecting means, which detects a misconvergence amount at each set point on the screen, which will be described later, and gives it to a coefficient calculating circuit 2 as a coefficient calculating means. ing.

The coefficient calculation circuit 2 is based on the amount of misconvergence provided from the detector 1, and the horizontal
The coefficients in the vertical direction are calculated and given to the microprocessor 3 as the control means.

The microprocessor 3 reads out the waveform parameters embodied as digital data from the waveform parameter ROM 4 as the waveform parameter storage means according to the coefficient given from the coefficient calculation circuit 2, and supplies this to the calculation RAM 5 as the signal synthesizing means. To synthesize. The combined signal waveform is temporarily stored in the correction data memory 6.

Reference numeral 7 is a PLL timing generator.
Both horizontal and vertical frequencies are input to the PLL timing generator 7, and according to these, a control signal necessary for synchronizing each set point and data is generated, and is supplied to the microprocessor 3 and the correction data memory 6. I'm giving.

Reference numeral 8 denotes a vertical interpolation calculation circuit, which performs vertical interpolation of correction points on the data stored in the correction data memory 6. This result is converted into an analog signal by the D / A converter 9 and, after passing through a low-pass filter (not shown), is passed through the correction coil as a convergence correction current.

FIG. 2 is a schematic diagram showing the setting position and misconvergence amount of each set point when the number of set points on the display screen is nine. P _{1 to} P ₉ shown by “◯” in FIG. 2 are set points on the display screen. Also,
a _i (i is 1 to 9) and b _i represent horizontal and vertical misconvergence amounts at each set point P _i . In addition,
When a _i or b _i is not explicitly shown in FIG. 2, it indicates that a _i or b _i is “0”.

The waveform diagram of FIG. 3 shows a sawtooth wave and a parabolic waveform which are part of the basic waveform stored in the waveform parameter ROM 4, respectively. The waveform shown in FIG. 3 is a state in which basic parameters are converted into analog signals.

A case will be described below in which the correction amount f is represented by a binary quadratic function having the horizontal scanning time th and the vertical scanning time tv as functions, as shown in FIG. In this case, the correction amounts in the horizontal and vertical directions are generally expressed by the correction formula of the following formula (1).

F (th, tv) = (k ₁ + k ₂ · th + k ₃ · th ² ) + (k ₄ + k ₅ · th + k ₆ · th ² ) · tv + (k ₇ + k ₈ · th + k ₉ · th ² ) · tv ² ... (1) where, th: horizontal scanning time of each correction point P ₁ to P ₉ through which the electron beam tv: vertical scanning time of each correction point P ₁ to P ₉ through which the electron beam k _i: each correction Coefficient of point P _i

In FIG. 1, the detector 1 has set points P _{1 to} P _1.
Horizontal misconvergence quantity a ₁ ~a ₉ of ₉ detects a vertical misconvergence quantity b ₁ ~b _9. From these detected amounts, the coefficient calculation circuit 2 obtains the coefficients k _{1 to} k ₉ in the horizontal direction and the vertical direction using the equation (1). Next, a method of calculating the coefficients k _{1 to} k ₉ by the coefficient calculation circuit 2 will be described.

In FIG. 2, set point P ₅ at the center of the screen is C
The time that the electron beam of the RT display passes is th = 0, tv ＝
0, and misconvergence amounts in the horizontal and vertical directions are a ₅ and b ₅ , respectively. At the set point P ₁ , the time taken for the electron beam of the CRT display to be th = −Th / 2, tv = −Tv / 2,
Set the horizontal and vertical misconvergence amounts to a _1,
If b ₁ and set point P ₉ , the time is th = + Th / 2, tv =
+ Tv / 2, to horizontal and vertical convergence error amount and a _9, b _9, respectively.

The values of the other adjustment points are determined in the same manner, and when these values are given to the above equation (1), the following equations are obtained.

(Horizontal direction) (Vertical direction) f (−Th / 2, −Tv / 2) = a ₁ b ₁ f (0, −Tv / 2) = a ₂ b ₂ f (+ Th / 2, −Tv _{/ 2) = a 3 b 3} f (-Th / 2, 0) = a 4 b 4 f (0, 0) = a 5 b 5 f (+ Th / 2, 0) = a 6 b 6 f (-Th / 2, + Tv / 2) = a ₇ b ₇ f (0, + Tv / 2) = a ₈ b ₈ f (+ Th / 2, + Tv / 2) = a ₉ b ₉

As described above, nine equations are established in each of the horizontal and vertical directions. From each of these equations, the coefficient k ₁
Obtaining ~ k ₉ gives the following equations.

K ₁ = a ₁ k ₂ = 1 / Th × (a ₄ + a ₆ ) k ₃ = 2 / Th ² × (a ₄ -2a ₅ + a ₆ ) k ₄ = 1 / Th × (−a ₂ + a) _{8) k 5 = 1 / Th} · Tv × (a 1 -a 3 -a 7 + a 9) k 6 = 2 / Th 2 · Tv × (-a 1 + 2a 2 -a 3 + a 7 -2a 8 + a 9) ^{_{k 7 = 2 / Tv 2 ×}} (a 2 -2a 5 + a 8) k 8 = 2 / Th · Tv 2 × (-a 1 + a 3 + 2a 4 -2a 6 -a 7 + a 9) k 9 = 4 / Th ²・ Tv ² × (a ₁ -2a ₂ + a ₃ -2a ₄ + 4a ₅ -2a ₆ + a ₇ -2a ₈ + a ₉ )

In the same manner, the misconvergence amounts a _{1 to} a ₉ in the above nine expressions are replaced with the misconvergence amounts b ₁ to a _9.
By substituting b ₉ , the coefficient in the vertical direction can be obtained.

Further, the waveform parameter ROM 4 has horizontal and vertical basics represented by f (th), f (th ² ), f (tv), f (tv ² ), etc. as shown in FIG. Parameters of the sawtooth wave and the parabolic wave, which are waveforms, are stored in advance. The microprocessor 3 calculates the misconvergence amount corresponding to the set points shown in FIG. 2 and the other screen positions from the basic RAM and the previously obtained coefficients by the calculation RAM 5.

Then, those data are stored in the addresses of the correction data memory 6 corresponding to the respective screen positions. Thereafter, similarly to the conventional example, the vertical interpolation calculation circuit 8 performs vertical interpolation, and the D / A converter 9 converts the signal into an analog signal for output.

Although not shown in the figure, the above-mentioned D
The analog signal output from the / A converter 9 is amplified by the output circuit after passing through the low-pass filter, and is used as the convergence correction current flowing in the correction coil. As a result, the direction of the electron beam is corrected, the convergence on the screen is corrected, and an image without distortion is obtained.

FIG. 4 is a schematic diagram showing a horizontal correction function and a correction name when represented by a binary quadratic function. For example, if the correction formula obtained by the detector 1 and the coefficient calculation circuit 2 is the following formula (2), it will be understood from FIG. 4 that the following correction is possible.

Th: H-Width th × tv: Keystone th ² × tv: Side-Skew tv ² : Bow th × tv ² : Pin

F (th, tv) = k ₂ · th + (k ₅ · th + k ₆ · th ² ) · tv
＋ k ₇ ＋ k ₈・ th) ・ tv ² = k ₂・ th + k ₅・ th × tv + k ₆・ th ² × ・ tv + k ₇・ tv ² + k ₈・ th × tv ² … (2)

The image distortion correction can be performed in the same manner as the above-mentioned convergence correction.

In the above embodiment, a correction waveform represented by a binary quadratic function was obtained from 9 set points.
From the correction amount (5 points in each of the horizontal and vertical directions), the correction waveform represented by the binary quaternary function expressed by the following equation (3) can be obtained.

F (th, tv) = (k ₁ + k ₂ · th + k ₃ · th ² + k ₄ · th ³ + k ₅ · th ⁴ ) + (k ₆ + k ₇ · th + k ₈ · th ² + k ₉ · th ³ + k ₁₀・ th ⁴ ) ・ tv + (k ₁₁ + k ₁₂・ th + k ₁₃・ th ² + k ₁₄・ th ³ + k ₁₅・ th ⁴ ) ・ tv ²・ ・ ・ ・ ・ ・ ・ ＋ (k ₂₁ + k ₂₂・ th + k ₂₃・th ² ＋ k ₂₄・ th ³ ＋ k ₂₅・ th ⁴ ) ・ tv ⁴ … (3)

Also in this case, the coefficient k is calculated by the coefficient calculation circuit 2.
Calculate _{1 to} k ₂₅ . When the number of correction points is 25 in this way, it is possible to perform convergence correction with higher accuracy.

FIG. 5 shows still another embodiment. In FIG. 5, reference numeral 1 is a detector, 2 is a coefficient calculation circuit, 3 is a microprocessor, 4 is a waveform parameter ROM, and 5 is for calculation.
RAM, 7 is a PLL timing generator, 8 is a vertical interpolation arithmetic circuit, and 9 is a D / A converter. In other words, the configuration shown in FIG. 5 is a configuration in which the correction data memory 6 is removed from the configuration shown in FIG.

In the embodiment shown in FIG. 5, the coefficient output of the coefficient calculation circuit 2 and the output data of the waveform parameter ROM 4 are combined by the calculation RAM 5, and this combined data is directly input to the vertical interpolation calculation circuit 8. And vertical interpolation is performed.
The other operations are similar to those of the embodiment shown in FIG. In the configuration shown in FIG. 5, the correction data memory 6 as a so-called buffer memory is omitted, but the processing speed of the microprocessor 3 and the processing speed of the circuits after the vertical interpolation calculation circuit 8 are synchronized. If so, the circuit configuration shown in FIG. 5 is simpler than that shown in FIG.

In each of the above embodiments, the detector 1 detects both vertical and horizontal misconvergence amounts to detect vertical and horizontal misconvergence.
Although it is configured to perform both horizontal correction, the detector 1
It goes without saying that it is possible to detect the misconvergence amount of either the vertical direction or the horizontal direction and correct only the vertical direction or the horizontal direction.

[0043]

As described in detail above, according to the present invention,
A convergence correction waveform expressed by a binary higher-order function from the coefficient calculated by the coefficient calculation main path from the result of detecting the amount of misconvergence of a color television receiver or the like and the waveform parameter stored in advance from the result. Therefore, it is also suitable for automatic adjustment, and it is possible to perform convergence correction with relatively high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a digital convergence correction device according to the present invention.

FIG. 2 is a schematic diagram showing setting positions and misconvergence amounts of the respective set points when the number of set points on the display screen is nine.

FIG. 3 is a schematic diagram showing a sawtooth wave and a parabolic waveform that are part of a basic waveform stored in a waveform parameter ROM.

FIG. 4 is a schematic diagram showing a horizontal correction function and a correction name when represented by a binary quadratic function.

FIG. 5 is a block diagram showing the configuration of another embodiment of the digital convergence correction device according to the present invention.

[Figure 6] NEC Corporate Bulletin Vol. 43 No. 4/1990 as a conventional example
FIG. 11 is a block diagram in which the configuration of the conventional digital convergence correction device disclosed in “Hi-Vision projector” is rewritten so as to be suitable for the description of the present invention to be described later.

[Explanation of symbols]

 1 Detector 2 Coefficient Calculation Circuit 3 Microprocessor 4 Waveform Parameter ROM 5 Calculation RAM

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 21, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention compensates for the color shift appearing on the screen of a video projector or a color television.
Color Television Convergence Correction to Correct
A converter that can be applied to equipment and also for image distortion correction
The present invention relates to a presence correction device.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art A picture tube of a color television using a shadow mask type three electron gun has three electron guns.
It is necessary to focus these electron beams on the phosphor screen,
Color video projectors have three colors on the screen
Since it is necessary to concentrate the light, the convergence correction
I need a road.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction content]

The operation of the conventional digital convergence correction device shown in FIG. 6 is as follows. For example, when a keyboard switch or the like (not shown) is operated, a control signal is input to the control terminal 30 accordingly. When this control signal is input, the microprocessor 3 receives, for example, FIG.
Basic waveform parameters such as a sawtooth wave and a parabolic wave shown in FIG. 3 (b) are read from the waveform parameter ROM4 and the adjustment level is set, and these basic waveforms are combined in the calculation RAM5. .. The desired correction waveform data thus obtained is stored in the correction data memory 6.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

Further, a horizontal synchronization signal and a vertical synchronization signal are input to the PLL timing generator 7, and a control signal necessary for synchronizing each correction point and data is generated according to these signals. Then, the data stored in the correction data memory 6 is vertically interpolated between the correction points by a known vertical interpolation calculation circuit 8, and the result is D / A.
After being converted into an analog signal by the converter 9 and passing through a low-pass filter (not shown), it is supplied to the correction coil as a convergence correction current. As a result,
The direction of the electron beam is corrected, the convergence on the screen is corrected, and an image without color shift is obtained.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

In the conventional digital convergence correction device, the engineer visually checks the screen as described above to detect the color misregistration state of the image, and manually operates an adjusting means such as a keyboard in order to eliminate it. Convergence correction is performed by generating a desired correction waveform.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

The present invention has been made in view of such circumstances, and it is a convergence for automatically eliminating color misregistration.
An object of the present invention is to provide a digital convergence correction device capable of correction.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

[0016] Microprocessor 3 is rated as digital data from the waveform parameters ROM4 as waveform parameter storing means in accordance with the coefficient given from coefficient calculating circuit 2
The stored waveform parameters are read out and given to the arithmetic RAM 5 as a signal synthesizing means for synthesis. The combined signal waveform is temporarily stored in the correction data memory 6.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

Although not shown in the figure, the above-mentioned D
The analog signal output from the / A converter 9 is amplified by the output circuit after passing through the low-pass filter, and is used as the convergence correction current flowing in the correction coil. As a result, the direction of the electron beam is corrected, the convergence on the screen is corrected, and an image with no color shift is obtained.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

F (th, tv) = k ₂ · th + (k ₅ · th + k ₆ · th ² ) · tv + (k ₇ + K ₈ ・ Th) ・ tv ² = k ₂ · th + k ₅ · th × tv + k ₆ ・ Th ² × tv + k ₇ · tv ² + k ₈ · th × tv ² … (2)

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction content]

[0043]

As described in detail above, according to the present invention,
The amount of misconvergence of a color television receiver or the like is detected by the detecting means, and the coefficient calculated by the coefficient calculating circuit from the result is expressed by a binary higher-order function from the waveform parameter stored in advance. Since it is configured so as to obtain a convergence correction waveform, it is possible to perform convergence correction that is suitable for automatic adjustment and that is relatively accurate.

Claims (1)

[Claims] 1. A waveform parameter storage means for digitally storing a basic correction waveform for convergence correction of a television signal, a control means for controlling an output level of the basic correction waveform from the waveform parameter storage means, and the control means. A signal synthesizing means for synthesizing signal data in which the output level of the basic correction waveform is controlled by
In a digital convergence correction device having an analog conversion means, a misconvergence amount detecting means for detecting the horizontal and vertical misconvergence amounts from a plurality of set points set on the screen, and the misconvergence amount detecting means are provided. Coefficient calculation means for calculating the coefficient of each term of the correction formula of the quadratic higher order function for horizontal correction and vertical correction with the horizontal scanning time and the vertical scanning time as variables from the detected misconvergence amount A digital convergence correction device, wherein the output level of the basic correction waveform is controlled according to the coefficient calculated by the coefficient calculation means.