JPH05198262A - Landing observation device for color cathode-ray tube - Google Patents

Abstract

PURPOSE:To detect even the slight mis-landing of an electron beam by dimming the predetermined value of brightness in the brightness gradation data of a phosphor dot for an enlarged pickup image, and displaying data regarding the addition of a contour line. CONSTITUTION:A CCD camera 3 picks up the enlarged image of the phosphor dot 5 of a cathode-ray tube 2, and prepares brightness gradation data. A device body 1 sends the data to a memory 17 via an A/D converter 16. The memory 17 saves comb teeth type data as a lookup table where every other output value becomes zero for input values. Thus, only an output value corresponding to the predetermined brightness value becomes zero, when reference is made to the table. As a result, data for adding a contour line 7 can be obtained. This data are temporarily saved in another memory 18, and sequentially read out for each frame for display on the screen of a monitor 4 via another A/D converter 19. In the case of proper landing, the center of the line 7 coincides with the center of the phosphor dot 5, and the position thereof varies, depending upon the extent of the mis-landing. Thus, the center of an electron beam can be clearly defined, and the direction and extent of the mis-landing can be easily identified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube landing observation device for observing the landing (color purity) state of a color cathode ray tube.

[0002]

2. Description of the Related Art FIG. 6 shows, for example, JP-A-62-171328.
It is a block diagram which shows the conventional color CRT landing observation apparatus shown by the publication. In the figure, 1 is a main body of the color cathode ray tube landing observation apparatus, and 2 is a color cathode ray tube (hereinafter referred to as CRT) in which a landing state is observed. Reference numeral 3 is a monochrome CCD camera as an image pickup means for picking up an image of the phosphor dots on the phosphor surface of the CRT 2 in an enlarged state, and 4 is a monitor for displaying the display data output from the apparatus body 1.

Further, in the apparatus body 1, 10 is a CPU for controlling the processing operation of the apparatus body 1 as a whole.
Reference numeral 1 is a program memory in which a program used for the processing is stored. Reference numeral 12 denotes an image input / output circuit that performs input / output processing with the CCD camera 3 and the monitor 4.
An image memory 3 stores the brightness gradation data from the CCD camera 3 and the display data displayed on the monitor 4. Reference numeral 14 is a storage disk for storing programs and data used in the CPU 10, and 15 is a system bus connecting the CPU 10 with the program memory 11, the image input / output circuit 12, the image memory 13, the storage disk 14, and the like. Is.

Next, the operation will be described. In the CRT 2, the R, G, and B electron beams are polarized, pass through the shadow mask, reach the phosphor surface, and are irradiated to the phosphor dots of the corresponding color, so that the phosphor dots emit light.
At that time, it is important to accurately irradiate the corresponding phosphor dot with the electron beam in order to maintain the color purity, and when the electron beam is mislanded out of the phosphor dot to be irradiated, color mixture occurs and the image Is difficult to see. Therefore, it is necessary to adjust the positions of the magnetic pole ring and the deflection yoke of the CRT 2 so that each electron beam is incident on the shadow mask at a predetermined angle and is accurately irradiated to each predetermined phosphor dot.

FIG. 7 is an explanatory diagram showing an example of observation of the landing state of the CRT2. In the figure, 5 is the CRT2.
And 6 is the irradiation range of the electron beam. Note that FIG. 7A shows a proper landing state, and FIGS. 7B and 7C show mislanding states having different degrees.
Here, the electron beam irradiation range 6 is set to be slightly larger than the phosphor dot 5 as shown in the drawing in order to allow a certain amount of landing.

Whether or not the electron beam is accurately irradiated on a predetermined phosphor dot 5 by adjusting the magnetic pole ring and the deflection yoke is determined by the CCD camera 3 which images the phosphor dot 5 of the CRT 2 in an enlarged state. It is determined by processing the brightness gradation data output by the device main body 1. Here, FIG. 8 is a flowchart showing a flow of processing by the CPU 10 in the apparatus main body 1, and FIG. 9 is an explanatory view showing the principle of the landing measurement.

The CCD camera 3 images the phosphor dots 5 of the CRT 2 in an enlarged state to generate luminance gradation data, and sends it to the apparatus body 1. The apparatus main body 1 stores it in the image memory 13 via the image input / output circuit 12, extracts the dot contour thereof, and calculates the luminance distribution of the dot peripheral portion (step ST1). Next, noise in the dot peripheral brightness distribution is removed using a median filter (step ST2), and an average value of the dot peripheral brightness distribution is obtained (step ST3). FIG. 9A shows the luminance distribution around the dots and the average value. Next, a dot peripheral portion having a luminance distribution equal to or less than the average value is detected as a chipped area (step ST4), and a start point and an end point of the chipped area indicated by d and e in FIG. The mislanding direction and its degree are calculated (step ST5). These arithmetic processings in the apparatus main body 1 are executed under the control of the CPU 10 using the program stored in the program memory 11.

[0008]

Since the conventional color cathode ray tube landing observation apparatus is constructed as described above, there is no missing area in the landing state shown in FIG. Since the difference is small, it is extremely difficult to detect the landing direction and its extent, and we cannot expect high-precision observation.
Even in the landing state shown in (c), step S
In the dot contour extraction processing executed at T1, the contour portion indicated by a in the irradiation range 6 of the electron beam and the phosphor dots 5 are
There is a problem that the highly reliable dot contour extraction processing cannot be performed because the contour portion indicated by b has a similar pattern.

The present invention has been made to solve the above problems, and it is an object of the present invention to obtain a color cathode ray tube landing observation apparatus which can accurately observe even a small amount of mislanding and has high reliability. To aim.

[0010]

In the color cathode ray tube landing observation apparatus according to the present invention, in the luminance gradation data of the phosphor dots of the CRT imaged by the imaging means in the enlarged state,
A brightness conversion unit for generating display data by reducing the brightness of a predetermined brightness value is provided.

[0011]

The brightness conversion means in the present invention receives the brightness gradation data of the phosphor dots of the CRT imaged in the enlarged state from the imaging means, and the brightness of the predetermined brightness value in the brightness gradation data. By generating the display data by dimming the display data, it becomes possible to display the display data to which the contour lines due to the light and shade of brightness are added, and it is possible to accurately observe even a small amount of mislanding, Realize a color cathode ray tube landing observation device that is also highly reliable.

[0012]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a main body of the apparatus, 2 is a CRT, 3 is a monochrome CCD camera as an image pickup means, 4 is a monitor, 10 is a CPU, 11 is a program memory, 14 is a storage disk, and 15 is a system bus. 6 are the same as or equivalent to those denoted by the same reference numerals, and detailed description thereof will be omitted.

Reference numeral 16 is an A / D converter for digitizing the brightness gradation data of the phosphor dots 5 of the CRT 2 imaged by the CCD camera 3 in an enlarged state, and 17 is a comb-teeth type as a look-up table. Data is set in advance, and a display in which the brightness of a predetermined brightness value in the digitized brightness gradation data is dimmed to "0" by using this look-up table, and contour lines are added depending on the brightness gradation It is a conversion memory as a brightness conversion means for generating data. Reference numeral 18 is an image memory that stores the display data generated by the conversion memory 17 for one frame.
Is a D / A converter that converts the display data stored in the image memory 18 into analog data and sends it to the monitor 4.

Next, the operation will be described. The CCD camera 3 images the phosphor dots of the CRT 2 in an enlarged state, generates brightness gradation data, and sends it to the apparatus body 1. In the device body 1, the A / D converter 16 receives it, digitizes it, and transfers it to the conversion memory 17. Now, when the electron beam is in the landing state as shown in FIG. 2A, the brightness of the phosphor dot 5 along the line AA is as shown in FIG. The distribution is highest in the center of range 6 and decreases as it goes to the periphery. In addition, 25 plotted on the vertical axis of FIG.
The numerical value of 5 is the 8-bit A / D by the A / D converter 16.
It is the maximum value when conversion is performed.

Here, in the conversion memory 17, as shown in FIG. 3, look-up table of comb tooth shape data in which the output value becomes "0" intermittently at a predetermined interval with respect to the input value. Is stored in advance. Therefore, A
When the lookup table is referred to by the brightness gradation data digitized by the / D converter 16, the output value corresponding to the predetermined brightness value becomes "0", and the other parts output the input values as they are. .. As a result, the digitized luminance gradation data becomes display data with contour lines added by the portion where the luminance value is dimmed to "0". FIG. 4 (a) shows such display data in the landing state shown in FIG. 2 (a).
(B) has shown the distribution of the brightness | luminance along the AA line. In addition, in FIG. 4, reference numeral 7 is a contour line due to the dimmed portion of the luminance value.

The display data thus generated is sequentially sent from the conversion memory 17 to the image memory 18 and temporarily stored. When the display data is stored in the image memory 18 for one frame, the display data is sequentially read out, sent to the D / A converter 19, converted into an analog form, and displayed on the monitor 4.
Is displayed on the screen. FIG. 5 is an explanatory diagram showing an example of an image displayed on the screen of the monitor 4 in each landing state. In the proper landing state, the center of the contour line 7 coincides with the center of the phosphor dot 5 as shown in FIG. 7A, and in the mislanding state, depending on the extent, the contour line 7B or FIG. As shown in FIG. In this way, since the contour lines 7 are drawn on the display image on the monitor 4, it is possible to clearly determine where the center of the electron beam is, and to easily determine the direction and degree of mislanding. You can

The CPU 10 controls these series of processing operations and provides the user with the most suitable creation and modification of the look-up table data. The control program and the data of the look-up table are stored in the storage disk 14 as a file and repeatedly used.

Example 2. In the first embodiment described above, the monochrome CCD camera 3 is used as the image pickup means, but a color CCD camera may be used. In that case, three sets of A / D converter 16, conversion memory 17, image memory 18, and D / A converter 19 are prepared, and processing is performed for each color of R, G, and B. It is possible to perform contour line processing on the luminance gradation data.

Example 3. Further, in each of the above-described embodiments, the data of the look-up table is stored as a file in the storage disk 14 and transferred to the conversion memory 17 each time to be processed, but the look-up table data is stored in advance. If it can be decided and need not be corrected, a ROM is used as the conversion memory 17, and the fixed look-up table data is written in the ROM. Since the program memory 11 and the storage disk 14 can be deleted, a more inexpensive color CRT landing observation device can be realized.

Example 4. Further, in each of the above-described embodiments, the case where only the luminance gradation data subjected to the contour line processing is displayed on the monitor 4 has been described, but the trajectory of the contour line 7 is obtained by the CPU 10 and the obtained trajectory of the contour line 7 is obtained. If the center position of the irradiation range 6 of the electron beam is calculated on the basis of this, and the center position is similarly calculated from the curvature of the outer circumference of the phosphor dot 5, mislanding of the two center positions will be performed. It is also possible to automatically determine the direction and its degree.

[0021]

As described above, according to the present invention, the brightness of the predetermined brightness value in the brightness gradation data of the phosphor dots of the CRT imaged in the enlarged state is dimmed. Since it is configured to generate display data, it is possible to display luminance gradation data with contour lines added, and even with a small amount of mislanding, it is possible to observe with high accuracy, and the reliability of observation results There is an effect that a high color CRT landing observation device can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a luminance distribution of phosphor dots imaged by the imaging means of the above embodiment and a landing state at that time.

FIG. 3 is an explanatory diagram showing an example of data of a lookup table in the above embodiment.

FIG. 4 is an explanatory diagram showing an example of display data and a luminance distribution thereof in the above embodiment.

FIG. 5 is an explanatory diagram showing an example of an image displayed on the display unit in each landing state of the above-described embodiment.

FIG. 6 is a block diagram showing a conventional color cathode ray tube landing observation device.

FIG. 7 is an explanatory diagram showing an example of observation of the landing state.

FIG. 8 is a flowchart showing the flow of the processing.

FIG. 9 is an explanatory diagram showing the principle of the landing measurement.

[Explanation of symbols]

 2 CRT (color cathode ray tube) 3 imaging means (CCD camera) 5 phosphor dots 17 brightness conversion means (conversion memory)

Claims (1)

[Claims] 1. An image pickup unit for picking up an image of a phosphor dot of a color cathode ray tube in which a landing state is observed in an enlarged state, and a predetermined brightness determination luminance data of the phosphor dot picked up by the image pickup unit. And a brightness conversion means for generating display data by dimming the brightness of a predetermined brightness value.