KR100409006B1 - Convergence Measuring Apparatus and Method of Color Cathode-Ray Tube - Google Patents

Abstract

An apparatus and method for measuring convergence of a color cathode ray tube according to the present invention includes a pattern generator for generating a measurement pattern on a screen of a color cathode ray tube, and a color camera for capturing a color cathode ray tube on which the pattern is output and converting the image into a digitized image signal. And an image processing unit including an image processing board, and a calculating unit processing an input image to calculate convergence, the distance measuring device having a thickness decreasing in the horizontal and vertical directions as the distance from the center coordinate of the measuring position decreases. By outputting a specific pattern characterized in that the brightness value of the center coordinate is the highest and the brightness value is lowered away from the center coordinate, to obtain the output value of the color sensor for the red, green, and blue phosphor of the color cathode ray tube, The color is then passed through a logical color sensor that can be detected independently. By performing an effect that can be measured with accurate convergence of the once image acquisition.

Description

Convergence Measuring Apparatus and Method of Color Cathode-Ray Tube}

The present invention relates to an apparatus and method for measuring the convergence of a color cathode ray tube, and in particular, captures a pattern of a specific shape on a color cathode ray tube using a single color camera and calculates the image information through a mathematical color separation process. The present invention relates to an apparatus and method for measuring the convergence of a color cathode ray tube capable of measuring the convergence of all positions of the cathode ray tube.

In the color cathode ray tube, as shown in FIG. 1, three electron beams output from three electron guns 1 of red, green, and blue pass through a shadow mask 3 through horizontal and vertical deflection coils 2. Then, three types of phosphors R, G, and B on the screen 4 are reached to generate light to form a screen.

For example, if you want to output a white line on the screen, red, green, and blue are output at the same time, but the three beams do not coincide on the screen and fall slightly. This is called mis-convergence. For short, it is called convergence.

In general, the electron beam emits not only one phosphor in the thickness direction of the line on the screen but also emits two to three or more phosphors as shown in FIG. 2, thereby determining the positions of red, green, and blue during the convergence measurement process. Therefore, the center of gravity of the weight of several phosphors can be calculated and calculated. In this case, when determining the center of gravity of each color of the three-color electron beam, various measurement methods exist to distinguish which color the phosphor belongs to.

The four types of conventional convergence measurement methods can be classified into a method of measuring convergence using a plurality of sensors, a method of measuring convergence using a single sensor, a method of measuring convergence using a monochrome camera, and a color camera. There is a method of measuring convergence using.

First, there are publication numbers 97-23582 and publication numbers 97-12878 as examples corresponding to the measurement of convergence using a plurality of sensors.

The publication number 97-23582 is configured as shown in Figure 3 relates to a method and apparatus for measuring the convergence of a color CRT using a plurality of photo sensors, the publication number 97-12878 shown in Figure 4 An apparatus and method for measuring the convergence of cathode ray tubes for measuring the convergence of the cathode ray tube (CRT) by measuring the convergence by acquiring images output from the cathode ray tube screen by a CCD (charge coupled device) camera during adjustment will be.

3 and 4, the method can measure the convergence of several positions, but each sensor requires a sensor for each position, which is difficult to maintain and repair, and to increase the number of measuring positions. If you do, you will have to fix the system. In addition, Japanese Laid-Open Patent Publication No. 2000-184401 measures convergence using three black and white cameras, which has a problem of matching synchronization signals.

Second, examples of measuring convergence using one sensor include Korean Publication No. 95-8334, Japanese Laid-Open Patent Publication No. 10-74456, and Japanese Laid-Open Publication No. 2000-125323.

Korean Publication No. 95-8334 relates to an apparatus and method for measuring convergence based on images captured by a black and white CCD camera in close proximity, and Japanese Laid-Open Patent Publication No. Hei 10-74456 photographing with a CCD color camera. An apparatus for measuring convergence from the position of each video signal, Japanese Laid-Open Patent Publication No. 2000-125323 measures a convergence based on an image taken close-up by a camera while moving a predetermined specific pattern minutely.

As described above, when measuring convergence using one sensor, all images should be photographed in close proximity, so that only one specific part of the color cathode ray tube can be measured. There is a problem that requires time.

Third, when the black camera is used as a sensor, color separation is not possible, so the red, blue, and green patterns are sequentially displayed, and the center position is obtained for each color. In this case, each color is displayed in turn, so that the white color that is the basis of the convergence measurement is raised to generate a difference from the measured value of the convergence. This is because it is different from displaying blue and green at once. This phenomenon is called cross-talk.

In order to solve the above problems, a method of calculating and compensating or simply disregarding the influence of the repulsive force according to the amount of convergence is used, which not only reduces the accuracy of the measurement but also takes a lot of measurement time because three image inputs are required. Has a problem.

Another method is to infer color information using one image input and color sequence of color dotted line already known using color dotted line that knows the order of red, blue, and green for convergence measurement. Although the number can be one, there is a problem that the accuracy of the measurement is lowered because a problem of crosstalk occurs because the white pattern is not used.

Fourth, in order to solve the problems caused when using the monochrome camera, a white pattern may be floated and the convergence may be measured using a color camera. In this case, convergence is obtained by recognizing red, blue, and green phosphors, calculating their positions, and finding the distance between the three beams.

At this time, the color filter of the color camera is used to distinguish each color. As shown in FIG. 5, the spectral spectrum of the phosphor is not clearly distinguished for each wavelength, but overlaps each other so that a bandwidth that can pass through is determined. Under no circumstances can the physical filter be used to determine the positions of the red, blue, and green (R1, B1, G1) without the influence of other colors.

That is, even if a red image is obtained using a filter that passes only 580 nm or more so that red (R1) passes well, the green phosphor also emits light of 580 nm or more, so that green (G1) actually contains a mixture of phosphor images. will be.

Convergence measurement method according to the prior art is difficult to maintain by using a plurality of cameras or sensors, the problem of system variability caused to increase the number of measuring positions, when measuring only one position by using one sensor In addition, the inconvenience and time-consuming problem caused by the measurement of the various positions, and when using a black and white camera, there is a need to acquire a number of times or cross-talk problem, when using a color camera, incomplete due to the use of a physical color filter There is a problem of color separation.

The present invention has been made to solve the above-mentioned problems of the prior art, the object of which is to capture a specific shape pattern on the color cathode ray tube using a single color camera and the image information through a mathematical color separation process It is to provide an apparatus and method for measuring the convergence of a color cathode ray tube that can measure the convergence of all positions of the colored cathode ray tube by calculating.

1 is a view showing the configuration of a common color cathode ray tube,

2 is a view showing a phosphor that emits light by an electron beam;

3 is a block diagram showing an apparatus for measuring convergence of a color CRT according to the prior art;

4 is a block diagram showing an apparatus for measuring the convergence of a cathode ray tube according to the prior art;

5 is a graph showing the spectral spectrum of the phosphor;

6 is a block diagram showing the configuration of an apparatus for measuring the convergence of a color cathode ray tube according to the present invention;

7a and 7b is a view showing a measurement pattern for the measurement pattern and color cathode ray tube for the convergence measurement according to the present invention,

8 is a flowchart illustrating a method for measuring convergence of a color cathode ray tube according to the present invention;

9 illustrates an image processing area according to the present invention.

<Explanation of symbols on main parts of the drawings>

10: color cathode ray tube 20: pattern generator

30: color camera 40: image processing board

50: calculator

According to a feature of the apparatus for measuring the convergence of a color cathode ray tube according to the present invention for solving the above problems, a pattern generator for generating a pattern for measurement so that a plurality of output at each measurement position of the screen of the color cathode ray tube for measurement of convergence Wow; An image processing unit including a color camera and an image processing board for capturing and converting the color cathode ray outputted from the pattern generator into a digitized image signal; In the apparatus for measuring the convergence of the color cathode ray tube, characterized in that it comprises a calculation unit for processing the image input to the image processing unit, the measurement pattern in the horizontal and vertical direction as the distance from the center coordinate of the measurement position The thickness decreases or the brightness value of the center coordinate of the measurement position is the highest, and the distance from the center coordinate is lowered.

In addition, according to a feature of the method for measuring the convergence of the color cathode ray tube according to the present invention, the pattern position for the convergence measurement is set on the screen of the color cathode ray tube and the measurement pattern generated from the pattern generator is output on the screen of the color cathode ray tube. A first step of doing; The color camera captures the measurement pattern image output by the red, green, and blue phosphors of the color cathode ray tube, digitizes it, and transfers it to the calculator, whereby the calculator can independently detect red, blue, and green output values. Passing a logical color sensor to perform color separation; The chromatic aberration of the color lens in use at the center coordinates of each color is calculated by calculating horizontal and vertical center coordinates of red, blue, and green at an arbitrary position using the red, blue, and green values calculated through the color separation of the second step. Compensation consists of a third step of measuring convergence.

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

6 is a view illustrating a configuration of an apparatus for measuring convergence of a color cathode ray tube according to the present invention, and a specific pattern to be displayed on the screen of the color cathode ray tube 10 and the color cathode ray tube 10 to be measured. A pattern generator 20 for generating and outputting, a color camera 30 for capturing the state of the pattern of the color cathode ray tube 20 and inputting it as an image signal, and a video signal transmitted from the color camera 30 digitally. And an operation unit 50 for performing color separation and image processing from the digitized image signal output from the image processing board 40 and calculating convergence.

The present invention provides a measurement pattern as shown in FIG. 7A to enable high-speed measurement of convergence at all positions of the color cathode ray tube 10 by one imaging using one of the color cameras 30. As shown in Fig. 2 outputs a plurality of color cathode ray tube 10 to the position to be measured.

The measurement pattern has a thickness that decreases in the horizontal and vertical directions as it moves away from the center coordinates, and the center coordinate portion of the measurement pattern is the brightest and darkens as it moves away from the center coordinates, particularly the horizontal and vertical angles. It can be implemented in the form consisting of four obtuse angles formed by connecting the four acute angles in the direction, and each acute angle in the other direction.

In this case, the measurement pattern is implemented as described above, so that the information of the center coordinates may be further included when obtaining the area center of brightness in the horizontal direction or the vertical direction.

In addition, in the present invention, in order to measure the convergence efficiently, the convergence may be measured from an image obtained by capturing one measurement pattern implemented using the color camera 30 only once.

However, in the measurement pattern implemented in the color cathode ray tube 10, red, blue, and green phosphors simultaneously emit white light. When the color camera 30 is used, characteristics of each phosphor are not clearly distinguished by wavelength. Red phosphors are detected in the blue and green channels as well as the red channel of the color camera 30, blue phosphors are detected in the red and green channels as well as the blue channel, and green phosphors are not only the red and blue channels, but also the green channel. Must be clarified because it is detected by.

When the red channel output of the color camera 30 is R, the blue channel output is B, and the green channel output is B, the R, G, and B are the brightness values of the image calculated by the actual sensor, and the image for each color. The brightness values are the same as in Equations 1, 2, and 3.

R = RR + RG + RB

G = GR + GG + GB

B = BR + BG + BB

Here, the front molecule refers to the CCD and the back letter refers to the phosphor. For example, GR means a value detected by the green CCD of the color camera 30 by the red phosphor of the color cathode ray tube 10.

In order to obtain accurate convergence, only the red, blue, and green images passing through the correct color filter should be used, which is RR, which is a value detected by the red phosphor by the red phosphor, GG, which is a value detected by the green phosphor, and This means that BB, which is a value detected by the blue phosphor by the blue CCD, should be used. If the values are R ', G', and B ', respectively, they can be calculated from R, G, and B using Equation 4.

Equation 4 may be regarded as a virtual camera system for the convergence measurement, wherein the image of the red phosphor appears only as the output of the red channel, the image of the green phosphor is the green channel output, and the image of the blue phosphor is the blue channel output. Only to appear.

The red channel output of the color camera 30 is the same value as R 'in the red pattern state, and the green channel output of the color camera 30 is the same value as G' in the green pattern state. In the state, the blue channel of the color camera 30 is equal to B '.

Based on the above facts, each of the red patterns in L different luminance states are floated and input to the color camera 30, and the outputs of the red channels are RR ₁ , RR ₂ , ..., RR _L , green. The channel outputs are called RG ₁ , RG ₂ , ..., RG _L , and the outputs of the blue channels are RB ₁ , RB ₂ , ..., RB _L , and the green patterns with M different luminance states Input to the color camera 30 to output the red channel output GR ₁ , GR ₂ , ..., GR _M , green channel GG ₁ , GG ₂ , ..., GG _M , blue channel output ₁ , GB ₂ ,..., GB _M , and each of the blue patterns with N different luminance states, respectively, and then captured by the color camera 30 to display the red channel outputs BR ₁ , BR ₂ , ... , BR _N, when the green channel output _{BG 1, BG 2, ...,} BG N, a blue channel output BB _1, BB _2, ..., BB _N that can produce a color-separation matrix from equation (5) have.

only, ,

X = RR ₁ RR ₂ … RR _L GR ₁ GR ₂ … GR _M BR ₁ BR ₂ … BR _N RG ₁ RG ₂ … RG _L GG ₁ GG ₂ … GG _M BG ₁ BG ₂ … BG _N RB ₁ RB ₂ … RB _L GB ₁ GB ₂ … GB _M BB ₁ BB ₂ … BB _N One One … One One One … One One One … One

,

Y = RR ₁ RR ₂ … RR _L 0 0 … 0 0 0 … 0 0 0 … 0 GG ₁ GG ₂ … GG _M 0 0 … 0 0 0 … 0 0 0 … 0 BB ₁ BB ₂ … BB _N

Is,

The color separation matrix is then a logical color sensor that enables color separation that is physically impossible.

The convergence measurement method of the color cathode ray tube 10 according to the present invention will be described with reference to the flowchart shown in FIG. 8.

In the first step, the position for outputting the measurement pattern for the convergence measurement of the color cathode ray tube 10 is set, and the second step is at the position of the color cathode ray tube 10 set in the first step in the pattern generator. A measurement pattern is output as shown in Fig. 7B (see S1 and S2).

In the third step, when the color camera 30 captures the color cathode ray tube 10 on which the measurement pattern of the second step is output and transmits the image to the image processing board 40, the image processing board 40 may do so. It is digitized and transmitted to the operation unit 50 (see S3).

The fourth step uses Equation 4 for the image processing region of the inner part of the dotted line including the measurement pattern around the pattern designation position as shown in FIG. 9 through the digital value transmitted in the third step. Red, green, and blue colors are separated by performing the color separation process (see S4).

The fifth step is the horizontal and vertical centers of red, green, and blue at arbitrary positions using Equations 6 to 11 to obtain area centers for R ', G', and B 'calculated in the fourth step. _{Calculate the} coordinates R _{cen_hori} , R _{cen_vert} , G _{cen_hori} , G _{con_vert} , B _{cen_hori} , and B _{cen_vert} .

Where x and y are pixel coordinates of the captured image, and R '(x, y) and G' (x, y), and B '(x, y) are R' at the image position (x, y) and It is the value of G 'and B'.

In the sixth step, a convergence is obtained by compensating chromatic aberration of the color lens currently used in the color camera 30 with respect to the center coordinates of the respective colors calculated in the fifth step.

As described above, the apparatus and method for measuring the convergence of a color cathode ray tube according to the present invention may perform color separation on image information photographed using one color camera and measure the convergence at an arbitrary position of the color cathode ray tube. .

The apparatus and method for measuring convergence of a color cathode ray tube according to the present invention configured as described above is cross-talk by using a specific white pattern in a form including more information of a center position as a measurement pattern for measuring convergence. It is possible to overcome the problem of compensation, and it is possible to measure convergence with a single image acquisition.

In addition, the apparatus and method for measuring the convergence of the color cathode ray tube according to the present invention is applied to a logical color sensor for color separation, which enables accurate convergence measurement. Convergence can be measured in a very short time for all positions, and the measuring device is simple, making it easy to maintain and maintain.

Claims (7)

A pattern generator for generating a measurement pattern such that a plurality of outputs are output at each measurement position of the screen of the color cathode ray tube for the convergence measurement; An image processing unit including a color camera and an image processing board for capturing and converting the color cathode ray outputted from the pattern generator into a digitized image signal; In the convergence measuring device of a color cathode ray tube, characterized in that the processing unit for processing the image input to the image processing unit to calculate the convergence, The measurement pattern is characterized in that the thickness decreases in the horizontal and vertical directions as the distance from the center coordinates of the measurement position, or the brightness value of the center coordinates of the measurement position is the highest, and the brightness value is lowered away from the center coordinates. Convergence measuring device of color cathode ray tube. The method of claim 1, And the calculating part includes a logical color sensor which detects output values of red, blue, and green independently and performs color separation. The method of claim 1, The measurement pattern has a octagonal shape consisting of four obtuse angles in the horizontal and vertical angular direction of the center coordinates, and four obtuse angles formed by connecting each acute angle in the other direction, the convergence measuring device of the color cathode ray tube . delete delete Setting a pattern position for convergence measurement on the screen of the color cathode ray tube and outputting the measurement pattern generated from the pattern generator to the screen of the color cathode ray tube; The color camera captures the measurement pattern image output by the red, green, and blue phosphors of the color cathode ray tube, digitizes it, and transfers it to the calculator, whereby the calculator can independently detect red, blue, and green output values. Passing a logical color sensor to perform color separation; The chromatic aberration of the color lens in use at the center coordinates of each color is calculated by calculating horizontal and vertical center coordinates of red, blue, and green at an arbitrary position using the red, blue, and green values calculated through the color separation of the second step. And a third step of measuring the convergence by compensating. The method of claim 6, In the second step, color separation is an output value of a physical color sensor for each level of brightness for red, blue, and green, and as an output, a response of other colors except for the corresponding color is output as 0. At the same time, the response of the corresponding color is carried out by implementing a logical color sensor using the output value of the physical color sensor.