JPS63221788A - Digital convergence device - Google Patents

Abstract

PURPOSE:To attain adjustment with high accuracy even for a signal of different scanning systems by calculating the amount of correction at each scanning line between vertical direction adjustment points and applying interpolation arithmetic between fields based on a discrimination signal of the scanning system. CONSTITUTION:The amount of convergence correction of each adjustment point read from a one-frame memory 10 is fed to a vertical direction adjusting point arithmetic processing section 28 and the amount of convergence correction for each scanning line between adjusting points is obtained by calculating from the difference of the correction of vertical adjusting points. On the other hand, a discrimination signal from a scanning discrimination section 26 is fed to an inter-field arithmetic processing section 27 and in case of the input signal of the sequential scanning system, an arithmetic processing section 28 is controlled so that the correction amounts of a 1st field and that of a 2nd field are made identical. In case of the input signal of a interlaced scanning system, the arithmetic processing section 28 is controlled to apply in-field interpolation arithmetic processing is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a device for correcting convergence in a color television receiver. The present invention relates to a digital convergence device that does not cause raster unevenness.

Conventional technology Generally, color television receivers have red and green.

An image is created by combining the three colors of blue on a fluorescent surface or a projected screen, but in this case, accurately aligning the three colors, that is, convergence adjustment, is an important issue that affects image quality. become.

Here, the convergence shift will be explained using a projection type color television receiver as an example.

In FIG. 6, numeral 1 indicates a projection screen for projecting an image, and numerals 2, 3, and 4 indicate projection tubes each equipped with an optical lens for forming an image obtained on a fluorescent surface onto the projection screen 1. Red on the fluorescent surface.

An image in three colors, green and blue, is obtained. As shown in Figure 6, when these projection tubes are arranged horizontally, the projection angles relative to the projection screen 1 are different, so the projected raster will be misaligned for each color as shown in Figure 7. . In FIG. 7, a solid line 3L shows a two-star projection of green light by the projection tube 3, a broken line 41 shows a raster of projection by the projection tube 4 of blue light, and a dashed-dotted line 2β shows a raster of projection of red light by the projection tube 2.

To correct this positional deviation, a convergence adjustment coil is installed separately from the main deflection yoke T in the projection tubes 2 and 3°4.
A sawtooth wave current with a horizontal scanning period is amplitude modulated with a vertical period,
The amplitude can be adjusted independently for each color.

However, this amount of color shift is due to variations in the mounting position of each projection tube, variations in the configuration of the optical lens system,
Since the convergence varies depending on changes in the projection screen position, etc., it is impossible to perform highly accurate convergence adjustment by simply using a sawtooth wave current or a combination of disjoint wave currents.

As a method for realizing such convergence adjustment, a convergence circuit having a digital correction waveform forming section has been considered.

The conventional digital convergence device will be explained in detail below using FIG.

Horizontal and vertical periodic pulses synchronized with the deflection current period are applied as synchronization signals, thereby driving the read address control unit 6. The pulse from the read address control section 6 is used to drive the crosshatch pattern generator 6 to project a crosshatch pattern on the projection screen. Figure 9 shows a crosshatch pattern. On the other hand, the address key of the control panel 12 is used to designate a cross point (for example, A in FIG. 9) at a position requiring convergence correction, and the position address is set in the write address control unit 8. Next, using the data write key for the color to be corrected, for example, red provided on the control panel 12, the amount of correction is written into the one frame memory 10 through the data reversible counter 11 while looking at the screen. Normally, this one-frame memory writing is controlled by switching by the multiplexer 9 so that it is performed during the blanking period of the video signal. Therefore, reading is not impaired. Similar operations are performed at each adjustment point as described above. Next, the readout of the one frame memory 1o is performed by the readout address control unit 5 for the cross position of each crosshatch on the screen, and through the register 18 driven by the readout address control unit 5, the vertical interpolation process is performed. A section 13 performs correction amount processing in the vertical direction between crosshatches.

Next, the operation of this correction process will be explained with reference to FIGS. 9 and 10.

The amount of correction for each scanning line between points A and B or between points 0 and D shown in FIG. 9 can be determined from (A-B) K+A or (C-D) K+C. Here, K indicates a value obtained by linear approximation, and is written in the ROM in advance. Therefore K
It is obvious that this can be determined from the number N of scanning lines between A and B. The number N of scanning lines is determined from the number M of scanning lines in one field and the number of horizontal lines in Kuromeno Tsuchi. Next, Figure 9A
, B-point correction amount processing will be explained with reference to FIG. The correction amounts of points A and B read out from the 1-frame memory 1° by the read address control unit 5 are registered in registers 1.18, 2, and 19.

The output signals of the registers 1.2, 18.19 are sent to the subtracter 2o, and multiplied by the coefficient for each scanning line from the coefficient generator 21 to obtain (A-B)K.
) K+A is sent out. In this way, the correction amount for the scanning line for which the correction amount is not stored is determined. Next, the output signal is converted into an analog quantity by the D/A converter 14 in FIG. Next, the correction amount in the horizontal direction is smoothed through a low-pass filter (LPF) 16, and is applied to the output amplification section 1e to supply a correction current to the convergence coil 17.

In the manner described above, the comparability adjustment at each adjustment point is performed.

Problems to be Solved by the Invention However, in conventional digital convergence devices, when input signals have different scanning methods such as progressive scanning and interlaced scanning, the correction amount for the 1st field and the 2nd field is always the same. The problem is that the continuity between the vertical correction amounts on the screen is lost during the signal, and the scanning speed is modulated by the discontinuous convergence correction amount between fields, resulting in vertical raster unevenness on the screen. It had a point.

In view of this, it is an object of the present invention to provide a digital convergence device that can perform accurate convergence adjustment without raster unevenness in the vertical direction even for signals of different scanning methods.

Means for Solving the Problems The present invention provides a storage means for digitally storing the convergence correction amount for each adjustment point, a succession means for successively reading the convergence correction amount from the storage means, and a signal input to the receiver. scanning discrimination means for discriminating the scanning method; vertical adjustment point-to-vertical adjustment point arithmetic processing means for calculating the correction amount for each scanning line between the vertical adjustment points using the convergence correction amount from the storage means; This is a digital convergence device comprising an interfield arithmetic processing means for performing an interpolation operation between fields of the vertical adjustment point arithmetic processing means based on a discrimination signal.

Operation Due to the above-described configuration, the present invention performs an inter-vertical adjustment point arithmetic process that calculates the amount of correction for each scanning line between the vertical adjustment points, and uses a scanning method discrimination signal to determine the amount of correction between the vertical adjustment points. By performing interfield calculation processing that performs interpolation between fields of processed data, accurate convergence adjustment can be performed without vertical raster unevenness, even for input signals with different scanning methods. It is something that can be done.

Embodiment FIG. 1 shows a block diagram of a digital convergence device in a first embodiment of the present invention. In FIG. 1, 26 is a scan discrimination unit that determines the scanning method, sequential scanning or interlaced scanning, based on the input synchronization signal, and 28 is a scanning discrimination unit that determines the convergence correction amount between adjustment points in the vertical direction based on the difference between the correction amounts of upper and lower adjustment points. An inter-field arithmetic processing unit 27 is an inter-field arithmetic processing unit that performs an interpolation operation between fields of data subjected to arithmetic processing between vertical adjustment points, based on a discrimination signal from the scanning discrimination unit 26. be. Note that the first
In the figure, parts that operate in the same way as in FIG. 8 are designated by the same numerals and explanations will be omitted.

The operation of the digital convergence device of this embodiment configured as described above will be described below.

A synchronization signal synchronized with the deflection arc period is applied to the scan discrimination section 26, and the timing of the vertical period pulse and horizontal period pulse is checked to determine whether sequential scanning or interlaced scanning is performed. The operation and configuration of the vertical adjustment point arithmetic processing section 28 are the same as those in the conventional one shown in FIG. I'm looking for it. The discrimination signal from the scan discrimination section 26 is supplied to the inter-field arithmetic processing section 27, and when it is an input signal of the sequential scanning method, the discrimination signal is sent between the vertical adjustment points so that the correction amount for the first field and the second field is the same. It controls the arithmetic processing section 28. When input signals are of the interlaced scanning method, the vertical adjustment point processing section 28 is controlled to perform interpolation calculation processing between fields, and by changing the calculation processing according to the scanning method, the vertical raster It eliminates unevenness.

Next, in order to explain in detail the operations of the inter-field arithmetic processing section 27 and the vertical direction adjustment point arithmetic processing section 28, which change the arithmetic processing according to the scanning method, The block diagram shown in Figure 4 is used. Figure 2a shows an enlarged view of the screen when an interlaced scanning input signal is supplied, where the solid lines 11 to 1!6 are the scanning lines of the first field, and the broken lines '11 to '15 are the scanning lines of the second field. Figure 2 shows the convergence correction amount from the conventional digital convergence device, and Figure 2 shows the correction amount (I0 ~x
4) in Figure 2C for each scanning line (111~
1), and the same correction amount OCo-X4) is read out for each field.

When the screen shown in FIG. 2a is corrected with the correction amounts in FIGS. 2 and 2c, since the correction amount is the same between fields as shown in FIG. 16) and the scanning lines (111 to 115) of the second field, and as the amount of correction increases, the scanning line pitch error between fields increases, causing raster unevenness in the vertical direction.

FIG. 3 shows an operation diagram when an input signal of the interlaced scanning method is supplied and the convergence correction amount is subjected to interfield interpolation calculation processing. Figure 3a shows an enlarged view of the same screen as Figure 2a, and Figure 3a shows the same correction amount (X O~X4 ) is shown. FIG. 3C shows the amount of correction for each scanning line (111 to 115) of the second field when performing interfield interpolation calculation processing, and shows the amount of correction for each scanning line (111 to 115) of the second field when the interfield interpolation calculation process is performed. The correction amount for X 2 scans 11 and 112 is □.
Similar calculations are performed from e13 to "14."

Figure 3 d shows the screen when the screen shown in Figure 3 a is corrected using the correction amount obtained by performing the inter-field interpolation calculation process in Figure 3 c. , the scanning line pitch between fields becomes equal, and vertical two-star unevenness can be eliminated.

Next, the operation of this arithmetic processing will be explained with reference to FIGS. 4 and 5. Note that in FIG. 4, parts that operate in the same way as in FIG. 10 are designated by the same numbers and their explanations will be omitted.

The amount of correction for each scanning line between point A and point B shown in Figure 6 is (A-
B) It can be determined from K, where K indicates a value determined by linear approximation and is written in the ROM in advance.

1 frame memory 10 by read address control unit 5
Point A read from.

The correction amount at point B is registered in registers 1.18 and 2.19. The output signals of registers 1.2, 18.19 are supplied to subtracter 2o. The synchronization signal is field discriminator 29
A scan discrimination section 26 consisting of the following performs scan discrimination and controls field coefficient generators 30 and 31. In the case of a progressive scanning signal, the coefficients from the first field coefficient generator 3o are selected, and the coefficients from the first field coefficient generator 3o are selected as shown by the white circles in FIG.

The coefficients of each scanning line from 1 to 6, which are the same coefficients for the second field, and the output from the subtracter 2o are multiplied by the multiplier 22, (A-B) k1 to 5 are obtained, and the adder 23 (A-B) 6 +A is sent out from k1. In this way, the correction amount for the scanning line for which the correction amount is not stored is determined. Next, when the signal is an interlaced scan signal, the first field coefficient generator 30 and the second field coefficient generator 31 are activated for each field by the discrimination signal from the field discriminator 29.
The coefficients from are selected. The coefficient of the first field shown in the white circle in Figure 6 is 1 to 6, and the coefficient of the second field is 1.
The output from the subtracter 2o is multiplied by the multiplier 22, and the first field is (A-B)k1~ by 5, and the second field is (A-B)k,1~ by 16. 16 is calculated, and the adder 23 adds 6↓A and ('')k to (A-B)k1~.
16+A is sent out from 11 onwards. In this way, the correction amount for the scanning line for which the correction amount is not stored is determined, and the correction amount is calculated by interpolating between fields. Performing convergence adjustment.

As described above, according to the present embodiment, in addition to the vertical adjustment point-to-vertical adjustment point calculation process that calculates the correction amount for each scanning line between the vertical adjustment points, the vertical adjustment point-to-vertical adjustment point calculation process is performed using the scanning method discrimination signal. By performing interfield arithmetic processing that interpolates between fields of processed data, highly accurate convergence adjustment can be performed without vertical raster unevenness even for input signals with different scanning methods. .

Note that although a projection type color television receiver has been described here for ease of understanding, it goes without saying that the present invention is also effective for a shadow mask type direct view type receiver.

As described in detail, according to the present invention, inter-field interpolation calculation processing is performed even for input signals of different scanning methods, so there is no rask unevenness in the vertical direction, and the accuracy is lower than the accuracy. Zense can be adjusted, and its practical effect is great.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a digital convergence device according to an embodiment of the present invention, Figures 2, 3, 4, and 5 are diagrams for explaining the operation of the embodiment, and Figure 6 is a block diagram of a digital convergence device according to an embodiment of the present invention. A principle diagram showing the principle of a projection type color television receiver, Fig. 7 is a diagram for explaining the convergence deviation, Fig. 8 is a block diagram of a conventional digital convergence device, and Figs. 9 and 10 are conventional diagrams. FIG. 3 is a diagram for explaining the operation of the digital convergence device. 1o...1 frame memory, 26...
Scanning discrimination unit, 27... Inter-field calculation processing unit, 28... Vertical direction adjustment point-to-point calculation processing unit, 8.
...Write address control section, 6...Write address control section. Name of agent: Patent attorney Toshio Nakao and 1 other personq
-1l -噸 噸口 4th figure I8 5th figure! ! Point A Lesson II Point 8 Figure 6 Figure 7

Claims (1)

[Claims] a display means for generating and displaying a plurality of convergence adjustment points in the horizontal and vertical directions on the screen of a color television receiver; an input means for inputting position information of the adjustment points; and a digital display means for inputting the convergence adjustment amount for the adjustment points. storage means for storing the convergence correction amount from the storage means; reading means for reading out the convergence correction amount from the storage means; scan discrimination means for determining the scanning method from the signal input to the receiver; a vertical adjustment point arithmetic processing means for calculating the correction amount for each scanning line between the adjustment points; and an interfield interpolation calculation of the vertical direction adjustment point arithmetic processing means based on a discrimination signal from the scanning discrimination means. A digital convergence device comprising inter-field arithmetic processing means for performing.