JP2807530B2 - Convergence measurement method and device and adjustment support device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring convergence of a color television or color display having stripe-shaped fluorescent dots, and an adjustment support apparatus.

[Prior Art] A conventional convergence measurement method for a color television is disclosed in Japanese Patent Application Laid-Open No. 61-257096, in which a measurement pattern is projected on a color television screen, and the image is input using a monochrome camera. Then, by switching the three primary color filters provided on the front of the camera, the convergence is measured by discriminating the colors of red, green and blue. Also, pages 67 to 69 of “Labor Saving and Automation” (Ohm, March 1986).
As discussed on the page, the convergence is measured by this image processing after color separation of the measurement cross pattern using a color camera.

[Problems to be Solved by the Invention] In the above-mentioned conventional technique, in the method using an optical filter, not only has time to switch the filter, but also it is necessary to perform three times of image capturing for performing one convergence measurement. Therefore, it was not suitable for high-speed measurement. In addition, since images of each color are captured at different timings, there is a problem that the measurement accuracy is reduced due to the influence of the variation of the deflection system on the color television side. On the other hand, in a method using a color camera, when a general color camera is used, the resolution is considerably reduced as compared with a black and white camera. Using a high-end color camera has made it possible to obtain a resolution comparable to that of a black-and-white camera. However, there is a problem that the cost is about 10 times that of a black-and-white camera, making it difficult to use in terms of cost.

An object of the present invention is to perform misconvergence measurement with only one image capture using a black and white camera,
It is an object of the present invention to provide a color television convergence measurement method, a device thereof, and an adjustment support device that can reduce the cost of the device and the measurement time.

Means for Solving the Problems In order to achieve the above object, a convergence measurement method and apparatus and an adjustment support apparatus of the present invention are configured to perform convergence measurement by inputting an image of a black and white cross pattern with a black and white camera. In the color discrimination, focusing on the fact that green is the brightest in the horizontal line, first identify the green fluorescent dots in the horizontal line, and then specify the other colors in accordance with the arrangement of the fluorescent dots, while identifying the green fluorescent dots in the vertical line. The color discrimination is performed by comparing the distance between the fluorescent dots determined by the horizontal line and the pitch between the fluorescent dots, and performing a weighted average processing of the brightness of each color on the fluorescent dots thus discriminated by the color to determine the line center position. Is obtained to obtain the amount of misconvergence.

In addition, in the convergence measurement of the vertical line, in order to use the same measurement method as the visual inspection of the television manufacturing process, it is determined whether the brightness of the fluorescent dot is a predetermined value or more for each color,
The misconvergence amount is obtained by obtaining both end positions of the vertical line of each color and setting the center thereof as the line center position.

[Operation] The above-described convergence measurement method and apparatus, and the adjustment support apparatus perform color discrimination processing by using the fact that green fluorescent dots are the brightest with respect to a measurement pattern imaged by a black-and-white camera. Since the line center position can be obtained, misconvergence measurement can be performed by one image capture, so that measurement time can be reduced and measurement accuracy can be improved.

In addition, as in the visual inspection, the brightness of the fluorescent dot is compared with a predetermined value to determine the both ends of green, and the center value is set as the line center position, so that correlation with visual observation can be easily obtained. ing.

Embodiment One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is an overall configuration diagram showing an embodiment of a convergence measuring method and device and an adjustment support device according to the present invention. In FIG. 1, the function and operation of each unit will be described first. The cross pattern generating circuit 1 sends a video signal to the color television 2 to project a black and white cross pattern 4 on the screen of the color CRT 3. The center of the cross pattern 4 is substantially the center of the cathode ray tube 3. The optical axis of the monochrome camera 5 is positioned by fixing means (not shown) so as to be at the center of the cathode ray tube 3. The image processing circuit 6 receives an image capture command 8 from the CPU 7
Is input, the image information of the monochrome camera 5 during one frame period is digitized in 64 gradations and stored in the frame memory 9. The frame memory 9 has a memory capacity of 512 × 512 × 6 bits. The CPU 7 performs convergence measurement processing based on the image data stored in the frame memory 9 based on a measurement algorithm described later, and displays the measurement results on the display device 10.

The basic method of the convergence measuring method according to the present invention shown in FIG. 1 is as follows.
Or, paying attention to the fact that it is brighter than the blue fluorescent dot 11c, the green fluorescent dot 11b is specified. On the other hand, focusing on the fact that the fluorescent dots of each color are regularly arranged at a predetermined pitch in the order of red, green and blue, the other red and blue fluorescent dots 11a are determined from the positional relationship with the green fluorescent dots 11b specified by the above method. , 11c. The misconvergence amount is calculated by calculating the line center of each color fluorescent dot by performing an arithmetic process for each color on the image near the center of the fluorescent dot whose color has been determined in this way. Next, the details of the convergence measuring method according to the present invention shown in FIG. 1 will be sequentially described with reference to FIGS.

FIG. 2 is an explanatory diagram showing a method of setting a measurement window of the cross pattern 4 in FIG. First, a method of setting the measurement window in FIG. 1 will be described with reference to FIG. Color television 2
Is performed for vertical and horizontal lines using the black and white cross pattern 4. Width W of vertical line measurement window 12
_VX, in the longitudinal direction lightness sum M _(X) in the measurement field of view 13, as the left end x _L and right x _R of the point as a vertical line detecting level or higher, x _R -
It is set to a value larger than x _L by at least the horizontal dot pitch (referred to as a distance between horizontally adjacent phosphors) W _{KX of the} phosphors in the left-right direction. The vertical width W _{Vy of the} vertical line measurement window 12
Is set to a value larger than at least the vertical dot pitch of the phosphor (meaning the distance between the upper and lower phosphors) W _Ky .

The width W _{Hy in} the vertical direction of one horizontal line measurement window 14 is
As upper y _U and lower y _L points as a horizontal line detection level or higher in the transverse direction lightness sum M _(y) in the measurement field of view 13, a slightly larger value in the vertical direction from y _L -y _U. Horizontal line measurement window 14
The width W _HX lateral so that at least the phosphor enters 6 or more, is set to satisfy the equation (1).

W _HX ≧ W _KX · 7 (1) The measurement windows 12 and 14 having the sizes set as described above are provided at predetermined positions in the measurement visual field 13. The position is desirably set near a point where the vertical line and the horizontal line of the cross pattern 4 intersect so that the measurement windows 12 and 14 do not interfere with each other. Using the images in the measurement windows 14, 12,
Misconvergence measurement of horizontal and vertical lines is performed based on the following measurement algorithm.

FIGS. 3 (a), (b), (c) and (d) are explanatory diagrams showing a method of obtaining the center position of red in the horizontal line in FIGS. 1 and 2. FIG. First, the horizontal line misconvergence measurement algorithm will be described with reference to FIG. Fig. 3 (a)
Is the red fluorescent dot 11a in the horizontal line measurement window 14 in FIG.
And the light emitting state of the green fluorescent dot 11b and the blue fluorescent dot 11c. In the figure, it is assumed that a hatched portion of each fluorescent dot emits light by an electron beam. As can be seen from the figure, the upper and lower positions where the fluorescent dots 11a, 11b, 11c of the respective colors emit light are different from each other, which indicates that a misconvergence state has occurred. FIG. 3 (b) shows a method of recognizing the center position of the fluorescent dot of each color from the vertical brightness sum _{MH (X)} of the image of FIG. 3 (a). The brightness of the fluorescent dots is higher at the center and lower at the periphery. Accordingly, as shown in FIG. 3 (b), the vertical lightness sum _{MH (X)} in the horizontal line measurement window 14 of FIG. 3 (a) is obtained by adding the fluorescent dots 11a, 11b,
There is one peak point every 11c. This peak position is set as the center position of the fluorescent dots 11a, 11b, 11c of each color. Furthermore, the brightness of the fluorescent dots of each color is 3 colors of red, green and blue.
Of the colors, green is generally the brightest. Therefore, the color determination of each fluorescent dot is performed by comparing the vertical brightness sum _{MH (X)} of each peak position in FIG.
Identify as 11b. Since the arrangement of the fluorescent dots 11a, 11b, 11c of the respective colors is determined for the color determination of the fluorescent dots at the other peak positions thereafter, it can be determined based on the previously identified green fluorescent dot 11b.

Next, FIG. 3 (c) shows a state where an image for measuring the center of the horizontal line is extracted for the example of the red fluorescent dot 11a among the fluorescent dots that have been color-discriminated by the above processing. For the sake of convenience, only the red dot will be described here, but the horizontal line center measurement for other colors is performed in the same manner.
Here, the center position of the red horizontal line measurement area 15a is a predetermined corresponding peak position of the above-described vertical brightness sum _{MH (X)} ,
The width of the red horizontal line measurement area 15a is set smaller than the width of the fluorescent dot 11a. FIG. 3D shows the horizontal brightness sum _{MHR (y)} of the image in the red horizontal line measurement area 15a of FIG. 3C. Here, the number of the red horizontal line measurement areas 15a to be calculated when calculating the horizontal lightness sum _{MHR (y)} is two.
However, any number may be used as long as the number is the same for each color. Here red horizontal center position Y _R is a distribution center in the lateral lightness sum M _HR determined by weighted mean processing shown in equation (2).

Y _R = ΣM _{HR (y)} · y / ΣM _{HR (y)} (2) Similarly, the center position Y _G of the green horizontal line and the center position Y _{B of the} blue horizontal line of the green fluorescent dot 11b and the blue fluorescent dot 11c.
Ask for. Next, the misconvergence amount is defined by a shift amount of red and blue with respect to green. Therefore, the red and blue horizontal line misconvergence amounts H _RG and H _BG are obtained by the equations (3) and (4).

H _RG = Y _R -Y _G (3) H _BG = Y _B -Y _G (4) FIGS. 4 (a), (b), (c) and (d) show FIGS. 1 and 2. FIG. 7 is an explanatory diagram showing a method for obtaining a center position of red color of a vertical line of FIG. Next, the vertical line misconvergence measurement algorithm will be described with reference to FIG. FIG. 4 (a) shows the light emission state of the red fluorescent dots 11a, the green fluorescent dots 11b and the blue fluorescent dots 11c in the vertical line measurement window 12 of FIG. In the figure, it is assumed that the hatched portion emits light. FIG. 4 (b) shows a method of recognizing the center position of each color fluorescent dot from the vertical brightness sum MV _(X) of the image of FIG. 4 (a). The recognition method performed as a horizontal line misconvergence peak position x _P1 ~x _Pm center position as in the measurement of Figure 3. Here, in the case of a vertical line, the brightest fluorescent dot may not be considered to be green depending on the state of misconvergence. Therefore, the distance between the fluorescent dot center position in the horizontal line measurement window 12 and the fluorescent dot center position in the vertical line measurement window 12, which has been color-discriminated earlier, is obtained.
The value of the remainder C _P at the time of dividing the distance in the lateral direction dot pitch D 3 times the value _P of the fluorescence dots by specifying the color. For example, the center position of the fluorescent dots for color determination of horizontal measurement window red color discriminated center position X ₁ and a vertical line measuring window 12 of the fluorescent dot 14 and _{X 2, | X 1 -X 2} | / When the remainder C _P obtained by calculating (3 · D _P ) is in the range of the equations (5), (6), and (7), the center position of the fluorescent dot is red,
It is determined that they correspond to the center positions of the green and blue fluorescent dots.

2.6 · D _P ≤ C _P or 0.4 ≥ C _P ... (5) 2.4 · D _P ≤ C _P ≤ 1.6 · D _P ... (6) 1.4 · D _P ≤ C _P ≤ 0.6 · D _P ... (7) Vertical line measurement window 12 according to various algorithms
Discriminate the color of the fluorescent dots inside.

Next, FIG. 4 (c) shows a state in which an image for measuring the center of the vertical line is extracted for an example of the red fluorescent dot 11a among the fluorescent dots that have been color-discriminated by the above processing. For the sake of convenience, only the red dot will be described here, but the vertical line center measurement for other colors will be performed in the same manner.
Here, the center position of the red vertical line measurement area 16a is a predetermined corresponding peak position of the above-described vertical direction brightness sum MV _(X) ,
The width of the area 16a is set smaller than the width of the fluorescent dot 11a. FIG. 4D shows the vertical lightness sum _{MVR (X)} of the image in the red vertical line measurement area 16a of FIG. 4C. From this red vertical line center position X _R is the longitudinal lightness sum M _VR distribution center _(X) obtained by weighted mean processing shown in equation (8).

X _R = ΣM _{VR (X)} · x / ΣM _{VR (X)} (8) Similarly, the green vertical line center position X _G and the blue vertical line center position X _{B of the} green fluorescent dot 11b and the blue fluorescent dot 11c are similarly obtained.
Ask for. Next, the red and blue vertical line misconvergence amounts V _RG , V _BG are determined by equations (9) and (10).

V _RG = X _R −X _G (9) V _BG −X _B −X _G (10) The misconvergence amount is obtained as described above.

5 (a), 5 (b) and 5 (c) are explanatory diagrams showing another method different from FIG. 4 for obtaining the center position of the red color of the vertical line in FIGS. 1 and 2. Next, another vertical line center position measuring method of the vertical line misconvergence measurement algorithm will be described with reference to FIG. First, the point of another method is to obtain the line center position based on whether or not the brightness of the fluorescent dot is equal to or more than a predetermined value, instead of using the above-mentioned load averaging process. This method is the same as the determination method in the case where the vertical line convergence inspection is visually performed in the television manufacturing process. In particular, in the case of measuring a vertical line of a television having a relatively large horizontal dot pitch of the phosphor, the correlation between the measurement result by the load averaging process and the judgment result by visual observation may not be good. The method addresses this. The differences from the vertical line center measurement method of FIG. 4 will be described below with reference to FIG. FIGS. 5 (a) and 5 (b) have the same contents as FIGS. 4 (a) and 4 (b), which have been described in detail above, and a description thereof will be omitted. FIG. 5C shows the vertical lightness sum MV _(X) at the center of the vertical line of the red fluorescent dot 11a. The red vertical line center position X _R is for its central position seeking end positions of fluorescent dots with emission determination level or brightness. Similarly, the center position of the vertical line of another color is obtained, and the light emission determination level is set for each color.

Next, a convergence adjustment support device using the above-described misconvergence measurement algorithm will be described.
Regarding the basic configuration, functions and operations of the convergence adjustment support device, the color television 2 in FIG. 1 is transported and positioned at a predetermined adjustment position by a conveyor while being mounted on a base plate (not shown), and is positioned by a camera positioning means. The measurement cross pattern of the screen of the color television 2 generated by the cross pattern generation circuit 1 is imaged by the monochrome camera 5 arranged at a predetermined position, and is taken into the frame memory 9 via the image processing circuit 6. The contents of the frame memory 9 are processed by the CPU 7 using the above-described misconvergence measurement algorithm, and the misalignment amount and the misalignment direction obtained as a result of the misconvergence measurement are sequentially graphically displayed on a monitor screen such as the display device 10. In this way, manual adjustment work is supported.
Note that the convergence adjustment support device can be configured as an automatic image quality adjustment device that performs image quality adjustment together with color purity adjustment and the like.

[Effects of the Invention] According to the present invention, convergence measurement of a color television can be performed by a single image capture using a black and white camera, so that there is an effect that measurement time can be reduced or measurement accuracy can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram showing an embodiment of a convergence measurement method and apparatus and an adjustment support apparatus according to the present invention, and FIG. 2 shows a method of setting a measurement window in FIG. FIGS. 3 (a) to 3 (d) are explanatory diagrams showing a method of obtaining the center position of red in the horizontal line in FIG. 1, and FIGS. 4 (a) to 4 (d) are vertical lines in FIG. FIG. 5 (a) to FIG. 5 (c) are explanatory diagrams showing a method of obtaining the center position of the red color.
FIG. 4 is an explanatory diagram showing another method for obtaining the center position of the red color of the vertical line in FIG. 1 ... Cross pattern generation circuit, 2 ... Color television,
3 ... color CRT, 4 ... black and white cross pattern,
5 black-and-white camera, 6 image processing circuit, 7 CPU
9: Frame memory, 10: Display device, 11a: Red fluorescent dot, 11b: Green fluorescent dot, 11c: Blue fluorescent dot, 12: Vertical line measurement window, 13: Measurement field of view, 14
…… Horizontal line measurement window, 15a …… Red horizontal line measurement area, 1
6a …… Red vertical line measurement area.

Claims (5)

(57) [Claims] 1. A black-and-white cross pattern is projected on a color television screen, the screen is imaged by a black-and-white camera, and red, green and blue line center positions of vertical and horizontal lines of the pattern are measured to perform convergence measurement. In this case, for the images in the vertical line measurement window that contains only vertical lines and the horizontal line measurement window that contains only horizontal lines, the peak points of the lightness sum when the vertical lightness sum is obtained The column is set as the center of the line center measurement area for each color, the vicinity of the center is set as the line center measurement area, and the color discrimination of the image in the measurement window is performed using the fact that the brightest fluorescent dot in the horizontal line is green. The fluorescent dot with the highest brightness among the brightness sums on the peak points in the peak point sequence of the brightness sum in the window is green, and the color discrimination of the fluorescent dots on the other peak points is based on the color arrangement of the fluorescent dots and the fluorescent dot. Convergence measurement method performed based on the pitch between dots, green center position of each color, wherein the determination by the weighted average processing of lightness sum of the image of the line center measurement area that color discrimination. 2. The center position of the both ends of the fluorescent dot having a lightness equal to or higher than the light emission judgment level provided for each color, instead of the load averaging processing of the lightness sum of the image in the line center measurement area discriminated by color. 2. The method according to claim 1, wherein
The convergence measurement method described. 3. A means for projecting a black-and-white cross pattern on a screen of a color television, a means for taking an image of the screen with a black-and-white camera, and red, green, and blue line center positions of vertical and horizontal lines of the pattern in the image. Measuring means for measuring convergence by measuring the vertical line measuring window having a size including only the vertical line and the horizontal line measuring window having a size including only the horizontal line. The peak point sequence of the brightness sum when each brightness sum is taken in the vertical direction is set as the center of the line center measurement area for each color, the vicinity of the center is set as the line center measurement area, and the color discrimination of the image in the measurement window is performed. Using the fact that the brightest fluorescent dot in the horizontal line is green, the fluorescent dot with the highest brightness in the sum of brightness on the peak points in the peak point sequence of the brightness in the horizontal line measurement window is set to green. The color discrimination of the fluorescent dots on the other peak points is performed based on the color arrangement of the fluorescent dots and the pitch between the fluorescent dots, and the line center position of each color is the sum of the brightness of the image in the line center measurement area that has been color discriminated. A convergence measurement device configured as means for performing convergence measurement obtained by a load averaging process. 4. The method according to claim 1, wherein the measuring means replaces the weighted average of the brightness of the image in the line center measurement area obtained by discriminating the line center position of each color with a fluorescent dot having a brightness equal to or higher than a light emission determination level provided for each color. 4. The convergence measuring device according to claim 3, wherein the convergence measuring device is configured as a means for obtaining a center position of both end edges of the convergence. 5. A convergence adjustment support device comprising the convergence measurement device according to claim 3 or 4, further comprising means for displaying the convergence measurement result.