JPH05207489A - Digital convergence correction device - Google Patents

Abstract

PURPOSE:To attain the storage and read of convergence correction data stored in a memory by compressing the convergence correction data at a high efficiency. CONSTITUTION:This digital convergence correction device provided with a memory 3 storing correction data, an address generating means 4 supplying an address to the memory 3, a D/A converter means 5 converting a memory output into an analog signal, a CPU 2 controlling the operation of the entire device and its peripheral input device 1 is provided with a compression write means 6 adopting the compression write method taking a difference between adjacent correction data, or the compression write method taking a difference of adjacent differential data between correction data of a middle cathode ray tube arranged in-line with respect to the screen and correction data of a cathode ray tube at its end, or the compression write method taking a difference between the correction data and its minimum data, or the compression write method storing the correction data at its minimum bit length and with a reproduction read means 8 employing the reproduction read method reproducing the compressed data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital convergence correction device such as a color TV or a display using a cathode ray tube, and more particularly to a storage / readout means for digital convergence correction data.

[0002]

2. Description of the Related Art As an example of a conventional digital convergence correction device, there is JP-A-61-73491. Regarding the correction data obtained by arranging some adjustment points on the screen and digitizing the convergence correction amount at the adjustment points, for example, an adjustment point outside the blanking period is A, and an adjustment point located before the adjustment point A. Is B and the adjustment point during the blanking period is C, and the correction data of the adjustment point are a, b, and c, respectively, the correction data a of the adjustment point A is different from the correction data b of the adjustment point B. Data a
-B is stored in the memory, and the correction data c at the adjustment point C is stored in the memory as it is.

[0003]

In the above-mentioned conventional technique, by storing the difference data between the correction data of the adjacent adjustment points, it is possible to obtain a correction signal having a large dynamic range even with a small number of bits. However, the basic component of the actual convergence correction data is the parabolic wave.

FIG. 3 shows an example of convergence correction data having a basic parabolic component. FIG. 4 is a diagram when the first-order difference is taken for the convergence correction data of FIG. If the correction data of the adjustment point for which the difference is taken is present on the parabola line shown in FIG. 3, the data obtained by the difference becomes a substantially straight line with a non-zero slope as shown in FIG. It wasn't small enough. Further, the correction data read out during the blanking period cannot be actually confirmed on the screen, and thus is often obtained by interpolation from the adjacent data. Therefore, when the data obtained by interpolation is included in the object for which the difference is taken, there is a problem that the compression rate becomes low.

An object of the present invention is to provide a digital convergence correction device that compresses the convergence correction data at the adjustment point with higher efficiency than before and stores it in a memory for data storage.

[0006]

The above-mentioned object is to provide compression writing means for performing compression by performing multiple difference calculation in convergence correction data of adjustment points for performing convergence correction for each color and each cathode ray tube. , And reproducing and reading means for reproducing the original correction data.

[0007]

[Function] Since there is no large difference between the convergence correction data of the adjacent adjustment points, the dynamic range of the data stored in the storage memory can be reduced by calculating the difference between the correction data of the adjacent adjustment points in the horizontal or vertical direction. it can. At this point, if further correlation is recognized between these difference data, the difference is again calculated in the horizontal direction or the vertical direction,
The dynamic range can be further reduced.
For example, when the difference between the correction data of the parabola adjustment points as shown in FIG. 3 is taken, the difference data (first-order difference data) becomes a linear function as shown in FIG. If the difference is further taken here, the difference data (second-order difference data) becomes a constant as shown in FIG. 5, and it is possible to compress almost only the variation components such as the cathode ray tube, the deflection system, the optical system, and the adjustment error. Become.

[0008]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 is a block diagram showing an embodiment of a digital convergence correction apparatus using the method of compressing and writing and reproducing the digital convergence correction data of the present invention. FIG. 2 is a flowchart of this embodiment. In FIG. 1, 1 is a keyboard (peripheral input device), 2 is a CPU that controls the operation of the digital convergence correction system.
(Central Processing Uni
t), 3 is a frame memory that stores the correction data of the adjustment points and the correction data of the points (correction points) of each scanning line or the adjustment points in the horizontal direction that require the correction data other than the adjustment points,
A RAM (Random Access Memory) is used. Reference numeral 4 is an address generating means for generating an address signal from a horizontal synchronizing signal, and 5 is a DAC (Digital-Analog) for converting a digital signal into an analog signal.
g Converter) and L for removing harmonic signal components
PF (Low Pass Filter), 6 is a compression writing unit for compressing the convergence correction data of the adjustment point,
Reference numeral 7 is a storage memory for storing the convergence correction data of the compressed adjustment points, which is an EEPROM (Electric).
all Erasable and Program
Able Read Only Memory) is used. Reference numeral 8 is a reproducing / reading means for reproducing the convergence correction data of the compressed adjustment points.

First, the operation at the time of digital convergence adjustment will be described with reference to the flowchart of FIG. The signal input from the keyboard 1 is analyzed by the CPU 2, the correction data of the adjustment point stored in the frame memory 3 is rewritten, and the interpolation processing of the correction data of the correction point is performed by the CPU 2 and the result is stored in the frame memory 3. Remember. Here, in the address generating means 4, a basic clock is generated by a horizontal synchronizing signal of the display signal or a signal synchronized with the horizontal synchronizing signal of the display signal, and a horizontal and vertical time is generated by the vertical synchronizing signal of the basic clock and the display signal or a signal synchronized therewith. An address corresponding to the target phase (corresponding to the position on the screen) is generated. By inputting the generated address into the frame memory 3, the correction data stored in the frame memory 3 is read out. The read correction data is input to the D / A, LPF 5 and converted from a digital signal to an analog signal to obtain a smooth convergence correction waveform. By repeating key input, a waveform required for convergence correction is created and adjustment is performed. When the adjustment is completed, only the correction data of the adjustment points stored in the frame memory 3 is input to the compression writing means 6 to compress the correction data of the adjustment points. The correction data of the compressed adjustment points are stored in the storage memory 7.

Next, the operation when the power of the digital convergence correction apparatus is changed from the OFF state to the ON state after the convergence correction will be described with reference to the flow chart of FIG. 2B. Since the frame memory 3 is composed of RAM, it does not always store the data before the power is turned off. Frame memory 3
If the previous data is stored in the memory, the correction data stored in the frame memory 3 is read by the address generated by the address counter generating means 4, and this is read by D
/ A and LPF5 to obtain a convergence correction waveform. When the frame memory 3 does not store the previous data, the correction data of the adjustment point is read out from the compressed and written data stored in the storage memory 7, and is input to the reproduction / readout means 8. The reproducing / reading means 8 reproduces the correction data of the compressed adjustment points. The reproduced data, that is, the correction data of the adjustment points is stored in the frame memory 3 and the CP
The correction data of the correction point is interpolated by U2, and the result is stored in the frame memory 3. Thereafter, the correction data is read from the frame memory in the same manner as when the frame memory 3 stores the previous data, and the convergence correction waveform is obtained. It should be noted that the CPUs 2, 6 and 8 may be replaced by one CPU 9.

FIG. 6 is a diagram showing the positions of the adjustment points arranged inside or outside the screen. The method of compressing and writing the convergence correction data at each adjustment point shown in FIG.

First, the first compression writing and reproduction reading method will be described.

FIG. 7 is a diagram showing a difference procedure of the convergence correction data adjacent in the scanning direction 1. A case where the first-order difference is obtained for the scanning direction 1 will be described with reference to FIG. First, the correction data of the twelfth column in the scanning direction 1 stored in the frame memory 3 and the column to the left of the correction data (first column)
The difference between the correction data of one column) is stored in the storage area of the twelfth column of the storage memory 7. The same operation is sequentially repeated for the eleventh column to the first column according to the arrows. The correction data of the 0th column in the scanning direction 1 is stored in the storage area of the 0th column of the storage memory 7 as it is. During reproduction, the data in the 0th column of the storage memory 7 and the data in the 0th column are stored in the storage memory 7 from the first column to the first column.
Data up to two columns are sequentially added as indicated by arrows and stored in the frame memory 3 to reproduce the correction data of the adjustment points. The same applies to the case where the first-order difference in the scanning direction 2 is obtained.

A case where the second difference is obtained in the scanning direction 1 will be described with reference to FIG. 10 is a CP that temporarily stores the data of the adjustment points when the CPU 9 is used
U's RAM. First, for the difference on the first floor, see FIG.
The difference is calculated in the same manner as in (a), and the first-order difference data is stored in the R of the CPU.
Store in AM10. Next, when the difference of the second floor is calculated, the first floor difference data stored in the RAM 10 of the CPU is set to 1
Similar to the case of taking the difference of the floor, from the 12th column to the 2nd column this time, the differences are sequentially taken according to the arrows and the second-order difference data is stored in the storage memory 7. The data in the 0th and 1st columns are stored in the storage memory 7 as they are. Where 3
Similarly, for the difference above the floor, C
The data is stored in the RAM 10 of the PU and the difference is stored in the storage memory 7. While the operation is repeated, the data in the first column of the storage memory 7 and the data from the second column to the twelfth column stored in the storage memory 7 are stored in the storage memory 7 at the time of reading, contrary to the storage. Are sequentially added as indicated by arrows and stored in the RAM 10 of the CPU. The data in the 0th column of the storage memory 7 is also stored in the RAM 10 of the CPU. Next, the correction data of the 0th column and the correction data of the 0th column of the RAM 10 of the CPU are sequentially added with the data of the 1st column to the 12th column, respectively, as shown by the arrows, and this is stored in the frame memory 3 and adjusted. Play the correction data of.
When the number of floors for which the difference is taken is 3 or more, reproduction is performed by repeating almost the same. The same applies to the case of taking the difference of two or more floors in the scanning direction 2.

FIG. 8 is a diagram showing a method of compressing writing and reproducing and reading data adjacent to the scanning direction 1 and the scanning direction 2. A case where the difference between the scanning direction 1 and the scanning direction 2 is calculated will be described. First, the difference is taken for the scanning direction 1, and then the difference is taken for the scanning direction 2. First, with respect to the difference in the scanning direction 1, the difference is obtained and stored in the RAM 10 of the CPU, similarly to the case where the second difference is obtained in the scanning direction 1.
Next, for the difference in the scanning direction 2, the difference is calculated for the first to twelfth columns in the scanning direction 1. 8th in scanning direction 2
The difference between the data of the row and the data of the row above it (seventh row) is stored in the storage memory 7. This is repeated from line 7 to line 1 according to the arrow. The data of the 0th row in the scanning direction 2 is stored in the storage memory 7 as it is. Similarly, when the difference is obtained, the target row and column are stored in the RAM 10 of the CPU and the difference is obtained and stored in the storage memory 7. On the other hand, at the time of reading, contrary to the case of storing, the reproducing and reading means 8 sequentially performs addition in the directions of the respective differences as indicated by the arrows and stores them in the frame memory 3 to reproduce the correction data of the adjustment points.

With respect to the compression writing / reproducing reading method, the number of floors for obtaining the difference from the scanning direction may be determined in advance. In addition, since the compression rate has data dependency, there is also a method of selecting the direction and the rank for taking the difference so that the dynamic range of the difference data is minimized. At this time, if the difference data, the data indicating the direction of obtaining the difference, and the data indicating the difference rank are stored in the frame memory 3, the most efficient compression can be performed regardless of the data. The latter takes a long time for compression, but there is no particular problem at the time of reproduction because it takes almost the same time as the former. The rows and columns to be stored in the storage memory as they are without compressing the correction data and the difference data are set to the 0th column, the 1st column, or the 0th row in the above description. There is no particular problem as a line. Further, regarding the data in the rows and columns, if the difference between adjacent data is obtained by the same means as above, the compression rate can be further improved. RAM1 of CPU
For 0, the frame memory 3 may be used instead. However, the convergence is disturbed during the period in which the frame memory 3 is used, but since it is a short period at the time of ending the convergence adjustment or turning on the power, there is no particular problem unless the screen is displayed during that period.

FIG. 9 is a diagram showing an example of convergence correction data at each adjustment point position in FIG. See also FIG.
FIG. 10 is a diagram showing correction data of each adjustment point in FIG. 9 compressed by using this embodiment. FIG. 10A shows data obtained by taking the first-order difference in the scanning direction 1. The 0th column in the scanning direction 1 is the correction data, and the others are the first-order difference data. Although the data surface created by the first-order difference data is smooth, it has some waviness. FIG. 10B shows data obtained by taking the second-order difference in the scanning direction 1. In the 0th column in the scanning direction 1, the correction data
The columns store first-order difference data, and the other columns store second-order difference data. Since the data surface created by the second-order difference data is flat and has no particular inclination, the dynamic range is smaller and the compression rate can be larger than that of the first-order difference data in FIG. 10A.

Next, the second compression writing / playback reading method will be described.

FIG. 11 is a diagram showing a cathode ray tube arranged in-line. Reference numeral 11 is a cathode ray tube arranged at the center, 12 is a cathode ray tube arranged at the left end, 13 is a cathode ray tube arranged at the right end, and 14 is a screen.
In general, the cathode ray tube 11 has G, the cathode ray tube 12 has R,
B is arranged in the cathode ray tube 13. In particular, a case where each of the cathode ray tubes arranged as shown in FIG. 11 is provided with a digital convergence correction function will be described.

FIGS. 12A and 12C are convergence correction data G and R for the cathode ray tubes 11 and 12, respectively, which include a large amount of correction amount due to variations in the deflection system in addition to the correction amount due to the optical system. Is. In addition, FIG.
(D) is first-order difference data G ', R'obtained on the correction data G, R by using a method similar to the first compression writing method. FIG. 12E shows trapezoidal distortion correction data R-G which is the difference between the colors of the correction data R of the adjustment points of the cathode ray tube 12 and the correction data G of the adjustment points of the cathode ray tube 11. 12
(F) is the first-order difference data (R- that is obtained by using the trapezoidal distortion correction data R-G by the same method as the first compression writing method.
G) '. As can be seen from FIGS. 12 (b) and 12 (d), in the data including many deviation components of the deflection system,
Even if the difference between the adjacent data is taken, the effect is small and the variation component becomes large. On the other hand, FIG.
The trapezoidal distortion correction data in (e) is smooth data.
This is because the deviation component of the deflection system is canceled by taking the difference between colors. Further, when the adjacent difference is taken for the data of FIG. 12E, the dynamic range of the data becomes small as shown in FIG. 12F, and even if the deviation of the deflection system is included, it can be stored in the memory with a small capacity. It will be possible.

FIG. 13 is a diagram showing a procedure when the inter-color difference and the adjacent difference are taken as the correction data. This will be described below with reference to FIG. First, the difference between the correction data R and B at the adjustment points of the cathode ray tubes 12 and 13 and the correction data G at the adjustment point of the cathode ray tubes 11 is calculated to obtain trapezoidal distortion correction data RG and BG.
It is stored in the RAM 10 of the PU. The correction data G of the adjustment point of the cathode ray tube 11 is stored in the RAM 10 of the CPU as it is. Next, the trapezoidal distortion correction data RG, BG and the correction data G stored in the RAM 10 of the CPU are subjected to the same operation as in the first compression writing method to obtain the difference data (RG). “, G”, (B−G) ′ is obtained and stored in the storage memory 7. At the time of reading, the data in the storage memory 7 is sequentially added by the same operation as in the first reproducing / reading method, and the correction data G and the trapezoidal distortion correction data RG and BG are reproduced and stored in the RAM 10 of the CPU. .. RAM of CPU
The trapezoidal distortion correction data RG and BG of 10 are added to the correction data G, and the reproduced correction data of R, G and B are stored in the frame memory 3.

In the above description, R,
The convergence correction device which stores the data of G and B and corrects by reading the data has been described, but the data of R-G, G, and B-G is stored in the frame memory 3 and the R-correction is performed at the time of correction. The above method may be applied to the convergence correction device for adding R to G and B to G to obtain R, G, and B. In this case, since R-G, G, and B-G are stored in the frame memory 3 in advance, it is possible to omit the inter-color difference and inter-color addition process shown in FIG.

Next, a third compression writing / playback reading method will be described.

FIG. 14 is a flow chart of the third compression writing / playback reading method. FIG. 15 is a diagram showing the relationship between the convergence correction data and the dynamic range. FIG. 15A shows the correction data itself as shown in FIG.
FIG. 15B is a diagram showing difference data between the correction data of FIG. 15A and the minimum data of the correction data. This will be described below with reference to the flowchart of FIG.

In the convergence correction data shown in FIG. 15A, the maximum data Dmax of the correction data is calculated by the CPU 9.
And the minimum data Dmin. Next, the difference between each correction data and the minimum data Dmin is obtained, as shown in FIG. Here, the dynamic range Dma of the correction data
From x-Dmin + 1,

[0027]

[Equation 1]

Find n that satisfies the above condition. n is the minimum data length (number of bits) required to represent the difference data. Therefore, the minimum data Dmin and the minimum number of bits n are stored in the storage memory 7 together with the difference data represented by n bits. At the time of reading, first, the minimum bit number n and the minimum data Dmin are read from the storage memory 7. Next, the n-bit stored data is sequentially read from the memory for storage, and at the same time, the minimum data Dmin is added and the result is stored in the frame memory 3. In this embodiment, since the dynamic range of the data to be stored is checked and the minimum number of bits required for the dynamic range is stored in the memory without a gap, the storage capacity of the memory is minimized and efficient compression is possible. Also, since the data length is known when reading, it is possible to reliably separate each data.

Generally, it is necessary to correct two colors of R, G, and B in order to perform the convergence correction, and to correct three colors in the case of also correcting the graphic distortion.
Two-dimensional (horizontal, vertical) correction is required for each color. Therefore, the correction data is also 4 lines or 6
System is required. Therefore, we investigated the dynamic range for all the systems of each convergence correction data,
Two methods are conceivable: a method of storing in a unified format and a method of checking the dynamic range for each system and storing in different formats. In the latter, even if a certain system has relatively large data, it does not affect the dynamic range of other groups, so it can be stored in a relatively small capacity in the memory. It is necessary to store Dmin for each system.

It is also possible to use this method by superimposing the difference data obtained by the first or second compression writing / reproducing reading method. Further, instead of taking the difference with the minimum data Dmin, the difference with the maximum data Dmax may be taken and the difference data may be stored.

[0031]

According to the present invention, the correlation of correction data for convergence correction is utilized to sufficiently compress and store the data in the memory, so that the capacity of the memory can be reduced. Therefore, even in a multi-scan display device or the like, it is possible to reduce the capacity of the memory that stores the convergence correction data necessary for each mode. Further, if it is not necessary to reduce the capacity, the resolution of each correction data can be increased with the same capacity, so that the convergence correction accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart of convergence correction.

FIG. 3 is a diagram showing an example of convergence correction data.

4 is a diagram showing a first-order difference of the convergence correction data of FIG.

5 is a diagram showing a second-order difference of the convergence correction data of FIG.

FIG. 6 is a diagram showing the arrangement of adjustment points inside or outside the screen.

FIG. 7 is a diagram showing a difference procedure of data adjacent in the scanning direction 1.

FIG. 8 is a diagram showing a difference procedure of data adjacent to scanning directions 1 and 2.

FIG. 9 is a relationship diagram between the adjustment point position and the convergence correction data.

FIG. 10 is a relationship diagram between adjustment point positions and convergence difference data.

FIG. 11 is a view showing a cathode ray tube arranged inline.

FIG. 12 is a diagram showing the relationship between adjustment point positions and trapezoidal distortion correction data.

FIG. 13 is a diagram showing an inter-color and adjacent difference procedure of correction data.

FIG. 14 is a flowchart of data length setting and minimum data difference.

FIG. 15 is a diagram showing a dynamic range of correction data.

[Explanation of symbols]

1 ... Keyboard, 2 ... CPU, 3 ... Frame memory, 4
... Address counter generating means, 5 ... D / A, LPF, 6
... compression writing means, 7 ... storage memory, 8 ... reproduction / reading means, 9 ... CPU, 10 ... RAM of CPU9.

Front page continuation (72) Inventor Kuninori Matsumi 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Stock company Hitachi Image Information Systems

Claims (5)

[Claims] 1. A memory for storing correction data, address generating means for supplying an address to the memory, digital-analog converting means for converting the memory output into an analog signal, a CPU for controlling the operation of the entire apparatus and its peripheral input device. In the digital convergence correction device, the compression is performed by targeting the convergence correction data in which the convergence correction amount is coded to obtain the Nth order difference (N ≧ 2) between the correction data adjacent in the horizontal scanning direction or the vertical scanning direction. A digital convergence correction apparatus comprising: a writing means and a reproducing / reading means for reproducing by adding the compressed data. 2. A memory for storing correction data, an address generating means for supplying an address to the memory, a digital-analog converting means for converting the memory output into an analog signal, a CPU for controlling the operation of the entire apparatus and its peripheral input device. With the digital convergence correction device, the convergence correction data of the cathode ray tube or the electron gun arranged inline with respect to the screen, the convergence correction data of the cathode ray tube or the electron gun at the end and the convergence correction data of the central cathode ray tube or the electron gun. For the difference data with respect to the data, a compression writing unit for performing compression by taking an Nth-order difference (N ≧ 1) to the difference data adjacent in the horizontal scanning direction or the vertical scanning direction, and the compressed data are added. And a reproducing and reading means for reproducing by reproducing. Digital convergence correction device that. 3. A memory for storing correction data, address generating means for supplying an address to the memory, digital-analog converting means for converting the memory output into an analog signal, a CPU for controlling the operation of the entire apparatus and its peripheral input device. In the digital convergence correction device, the convergence correction data or the difference data thereof is targeted to obtain the maximum or minimum data of the target data,
A digital convergence correction apparatus comprising: a compression writing unit that takes a difference between all data of the target data and a maximum or minimum data; and a reproduction reading unit that reproduces by adding the compressed data. 4. A memory for storing correction data, an address generating means for supplying an address to the memory, a digital-analog converting means for converting the memory output into an analog signal, a CPU for controlling the operation of the entire apparatus and its peripheral input device. In the digital convergence correction apparatus, the convergence correction data or the difference data thereof is targeted, and a value Dmax-Dmin + is obtained by adding 1 to the difference between the maximum data Dmax and the minimum data Dmin of the target data.
A compression writing means for determining a data length sufficient to code 1 and storing each of the target data in the memory with the data length, and storing data indicating the data length in the memory, and the number of bits. And a reading means for reading the target data on the basis of the data indicating the above. 5. The digital convergence correction apparatus according to claim 4, wherein the convergence correction data or the difference data thereof is grouped for each color and correction direction to perform compression writing and reproduction reading, and reproduction. A digital convergence correction apparatus, which is provided with a reading means.