JP2001359128A - Missed convergence measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a missed convergence measurement device that can securely measure a missed convergence amount at a high-speed with high accuracy even when a color temperature of a display pattern is changed. SOLUTION: An image pickup device 11 is provided with a monochrome CCD area sensor and an optical filter that has a spectral transmissivity characteristics to bring a spectral sensitivity characteristics of this sensor to a characteristics in which any fluorescent color a color CRT 3 is maximized. The image pickup device 11 picks up an image of a test pattern displayed in white on the color CRT 3 and a VRAM123 in a measurement device main body 12 stores the picked-up image. A control section 128 extracts an image signal with a maximum level to separate an image in one fluorescent color, extracts an image signal of other level depending on the position of the image signal and the arrangement relation of fluorescence to separate an image in other fluorescent color, and by using the image of the test pattern of each fluorescent color a missed convergence amount is calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color CRT 3
The present invention relates to a misconvergence measuring device for measuring a misconvergence amount for evaluating the concentration state of electron beams in a book.

[0002]

2. Description of the Related Art Conventionally, in order to adjust convergence of a color CRT, a test pattern for measurement displayed on a color CRT is photographed by a camera, and a misconvergence amount is calculated by using the photographed image to calculate a misconvergence amount. Devices are known.

For example, Japanese Patent Laid-Open Publication No. Hei 1-102833 discloses that a test pattern displayed on a color CRT is photographed by an image pickup device using a single-plate type color area sensor, and R, G, B color components are obtained from the image pickup device. 1 shows a misconvergence measuring device that calculates a misconvergence amount using a photographed image that has been decomposed and output.

An imaging device using a single-plate type color area sensor as an imaging device for a misconvergence measuring device only needs to photograph a test pattern displayed in white only once in order to capture an image of the test pattern. Although there is an advantage that the speed can be increased, there is a disadvantage that the resolution of a captured image is low and measurement accuracy is low as compared with an imaging device using a monochrome area sensor (hereinafter, referred to as a monochrome imaging device).

[0005] Therefore, there has been proposed a misconvergence measuring device provided with a monochrome image pickup device and capable of speeding up the measurement without lowering the measurement accuracy. For example, Japanese Patent Application Laid-Open No. 3-253198 discloses that a test pattern displayed in white on a color CRT is photographed by a monochrome image pickup device, and a portion having the highest luminance level in the photographed image is emitted from a G (green) phosphor. , While R
By specifying the portions of the phosphors of (red) and B (blue) emitted by the phosphors in accordance with the arrangement of the phosphors, it is possible to obtain an image of each color component of the test pattern with a high resolution in one photographing operation. Misconvergence measuring devices have been proposed.

Japanese Patent Application Laid-Open No. Hei 5-111060 discloses that a test pattern displayed in white on a color CRT is photographed by a monochrome image pickup device, and a portion of the photographed image having the lowest luminance level is represented by R (red). On the other hand, the portions of the phosphors G (green) and B (blue) are specified according to the arrangement of the phosphors.
There has been proposed a misconvergence measuring device capable of obtaining an image of each color component of a test pattern having a high resolution in a single photographing operation.

Japanese Unexamined Patent Publication No. Hei 3-258188 discloses a monochromatic image pickup apparatus which captures a raster pattern formed by making the luminance of each of R, G, and B color components different from each other on a color CRT and using a monochrome image pickup apparatus. The light emission positions of the phosphors of the respective color components are calculated in advance, and a test pattern composed of a cross hatch pattern displayed in white at the time of measurement is imaged.
By separating the captured image into images of R, G, and B color components based on the light emission position of the phosphor calculated from the captured image of the raster pattern, it is possible to obtain an image of each color component of the test pattern with high resolution. There has been proposed a misconvergence measuring device which can be used.

[0008]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 3-253 is disclosed.
The misconvergence measuring apparatus described in Japanese Patent Application Publication No. 198-198 specifies the maximum output portion of the luminance data of a captured image as a portion due to the emission of the G phosphor.
The misconvergence measuring apparatus described in Japanese Patent Application Laid-Open No. 1116060 specifies the minimum output portion of the luminance data of the captured image as the portion due to the emission of the R phosphor. The portion is caused by the light emission of the G phosphor, and the portion having the minimum output is not necessarily the portion caused by the light emission of the R phosphor. Therefore, there is a problem in the reliability of the measurement result.

That is, for example, a CCD (Charge-Coupled)
The spectral sensitivity characteristics of a monochrome area sensor composed of a device (device) are generally as shown in FIG. 20, and do not have a steep sensitivity region in the visible region. On the other hand, the spectral emission characteristics of the R, G, and B phosphors of the color CRT are generally as shown in FIG.
The light emitting region has a wavelength around m, a wavelength around 550 nm, and a wavelength around 450 nm.

The color temperature of a pattern displayed on a color CRT is generally adjusted in the range of 5000K to 12000K. However, if the color temperature of the display pattern is different, the color component at which the luminous intensity becomes maximum changes, for example, 5000K. And the display pattern of 6500K,
The emission intensity of the R phosphor relative to the G phosphor is 5000K.
Are larger.

Therefore, when a pattern displayed on a color CRT is photographed by a monochrome area sensor, R, R,
The ratio of the output level corresponding to the light emitting portion of each of the G and B phosphors changes according to the color temperature of the display pattern.

Table 1 shows the change in the light receiving component ratio of the monochrome area sensor with respect to each of the R, G, and B phosphors when the color temperature of the display pattern is changed.

[0013]

[Table 1]

As shown in Table 1, if the color temperature of the display pattern is 6500K, the light emitting portion of the G phosphor becomes maximum. Therefore, the portion having the maximum output is specified as the light emitting portion of the G phosphor. Is possible, for example, if the color temperature of the display pattern is 5000K, the light emitting portion of the G phosphor and the light emitting portion of R have substantially the same output level. Cannot be specified. Therefore, the image of the R, G, and B color components cannot be accurately separated from the captured image, and the amount of misconvergence cannot be accurately calculated.

On the other hand, the color temperature of the display pattern is 12000
In the case of K, the light emitting portion of the phosphor of B becomes the maximum,
Specifying the maximum output portion as the light emitting portion of the G phosphor,
The color component separated from the photographed image is completely different from the true color component, resulting in erroneous measurement.

Further, the misconvergence measuring apparatus described in Japanese Patent Application Laid-Open No. HEI 5-111060 needs to photograph both a raster pattern and a test pattern when measuring the amount of misconvergence.
The measurement time is longer than that described in JP-A-8188. When the positional relationship between the color CRT and the imaging device changes between the time of photographing the raster pattern and the time of photographing the test pattern, the photographing of the test pattern is performed based on the light emitting position of the phosphor calculated from the photographed image of the raster pattern. The image cannot be separated into R, G, and B color component images, which may result in erroneous measurement.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a misconvergence measuring apparatus provided with a monochrome image pickup apparatus which is stable and accurate even when the color temperature of a display pattern is changed, and which is capable of quickly performing a mistake. An object of the present invention is to provide a misconvergence measuring device capable of measuring a convergence amount.

[0018]

According to the first aspect of the present invention,
A predetermined test pattern displayed by irradiating each of the phosphors of a plurality of colors applied on the face plate of the color CRT in a predetermined color arrangement with an electron beam is photographed by a monochrome type imaging means, and set as the photographed image. A misconvergence measuring apparatus for measuring the amount of misconvergence of the color CRT using image data of a test pattern in a measurement area to be measured, wherein an optical system for guiding a light image of the test pattern to an imaging surface of the imaging means; Spectral transmittance provided on the optical path of the optical system, such that the spectral sensitivity characteristic of the imaging surface of the imaging means has the maximum or minimum sensitivity in any one phosphor color region of the phosphors of a plurality of colors. An optical filter having characteristics, and the measurement area based on a level of image data of the photographed image and a color arrangement relationship of the phosphor. A color separating unit for separating the image data of the test pattern into image data of the color component of the phosphor, and calculating the amount of misconvergence using the image data of the test pattern for each color component separated by the color separating unit. Calculation means for performing the calculation.

According to the above configuration, the amount of misconvergence can be determined by irradiating a plurality of color phosphors coated on the face plate in a predetermined color arrangement with an electron beam to apply a predetermined test pattern to the color CRT to be measured. It is displayed, the test pattern is photographed by a monochrome type imaging means, and is calculated using the image data of the test pattern in the measurement area set in the photographed image.

Since the image pickup system has an optical filter on the optical path of the optical system, the spectral sensitivity characteristic of the entire image pickup system is the product of the spectral sensitivity characteristic of the image pickup means alone and the spectral transmittance characteristic of the optical filter. The spectral sensitivity characteristic of the surface has a maximum or minimum sensitivity in any one phosphor color region of the phosphors of a plurality of colors.

Accordingly, by extracting the image data of the maximum or minimum level from the image data of the photographed image, the image data of the phosphor color corresponding to the level of the test pattern is separated. Further, image data of another phosphor color is separated by extracting image data having another level from the arrangement relationship of the phosphors.

Then, a misconvergence amount, which is a shift amount between the test patterns of each color, is calculated using the image data of the test patterns separated by color.

According to a second aspect of the present invention, in the misconvergence measuring device, the optical filter has a spectral sensitivity characteristic of a plurality of colors of at least a portion including an area where the measurement area is set on the imaging surface of the imaging means. It has a spectral transmittance characteristic such that the characteristic has the maximum or minimum sensitivity in any one phosphor color region of the phosphor.

According to a third aspect of the present invention, in the misconvergence measuring apparatus according to the second aspect, the color separation means includes a level of image data of a test pattern included in the measurement area of the photographed image and a level of the fluorescence. The image data of the test pattern in the measurement area is separated into the image data of the color component of the phosphor based on the color arrangement relationship of the body.

According to this configuration, the spectral sensitivity characteristic of the portion including the region where the measurement region on the imaging surface is set is a characteristic having the maximum or minimum sensitivity in any one of the phosphor color regions of the plurality of color phosphors. Therefore, the image data of the phosphor color corresponding to the level of the test pattern is separated by extracting the image data of the maximum or minimum level from the image data in the measurement area set in the captured image. Then, image data of another phosphor color is separated by extracting image data having another level from the arrangement relationship of the phosphors. Then, a misconvergence amount, which is a shift amount between the test patterns of each color, is calculated using the image data of the color-separated test patterns.

Specifically, R, G,
The amount of misconvergence of a color CRT in which a plurality of phosphors of each color of B are applied in a predetermined arrangement relationship is R,
Each of the G and B phosphors is irradiated with an electron beam of substantially the same level to display a predetermined test pattern in white on a color CRT, photograph the test pattern, and scan a predetermined measurement area set in the photographed image. It is calculated using the image data of the test pattern.

If the spectral sensitivity characteristic of the portion including the region where the measurement region of the imaging surface of the entire imaging system is set is a characteristic having the maximum or minimum sensitivity in the G color region, for example, it is set to the photographed image. The image data of the test pattern of G color is separated by extracting the image data of the maximum or minimum level from the image data in the measured area. Further, by extracting image data of a predetermined output level located on the left side of the image data of the maximum or minimum level from the RGB arrangement relationship, the image data of the test pattern of R color is separated, and the maximum or minimum level is extracted. By extracting the image data of a predetermined output level located on the right side of the image data of B, the image data of the test pattern of B color is separated. Then, a misconvergence amount, which is a shift amount between the test patterns of the respective colors, is calculated using the image data of the test patterns of the respective colors R, G, and B that have been color-separated.

According to a fourth aspect of the present invention, in the misconvergence measuring apparatus, the optical filter is formed of a phosphor of a plurality of colors having a spectral sensitivity characteristic of at least a portion of the imaging surface of the imaging means that does not include the measurement region. Any one
Has a spectral transmittance characteristic such that the characteristic has the maximum or minimum sensitivity in the phosphor color region.

According to a fifth aspect of the present invention, in the misconvergence measuring apparatus according to the fourth aspect, the color separation means includes an image data of a test pattern included in a certain area not including the measurement area of the photographed image. Is separated into image data of the color components of the phosphor based on the level of the image data and the color array relationship of the phosphor, and the image data of the test pattern and the color array relationship of the phosphor for each color component are separated. The image data of the test pattern in the measurement area is separated into the image data of the color component of the phosphor on the basis of the measurement pattern.

The region not including the region where the measurement region is set may be a peripheral region of the captured image.

According to the above arrangement, the misconvergence amount is determined by irradiating the plurality of color phosphors applied to the face plate in a predetermined color arrangement with electron beams at substantially the same level to the color CRT to be measured. Is displayed, the test pattern is photographed by a monochrome type image pickup means, and the test pattern is calculated using image data of the test pattern in a predetermined measurement area set in the photographed image.

Since an optical filter is provided on the optical path of the optical system in the imaging system, the spectral sensitivity characteristics of an area that does not include the area where the measurement area of the imaging plane is set, for example, the area around the imaging plane, The characteristic has the maximum or minimum sensitivity in one of the phosphor color regions.

Therefore, first, a color discrimination area is set in an area that does not include the area where the measurement area of the photographed image is set and that includes the test pattern, and the maximum or maximum of the image data in the color discrimination area is set. By extracting the image data of the minimum level, the image data of the phosphor color corresponding to the level of the test pattern is separated. Further, image data of another phosphor color is separated from image data having another level based on the arrangement relationship of the phosphors.

In the entire photographed image, the image data obtained by receiving the light emission of the phosphor of each color is arranged in a predetermined arrangement relationship.
The image data of the test pattern in the measurement area receives light emission of any phosphor color based on the position of the image data of each phosphor color separated in the color determination area and the arrangement relationship of the phosphor colors. By determining whether or not the image data is divided into image data of each phosphor color. Then, a misconvergence amount, which is a shift amount between the test patterns of each color, is calculated using the image data of the color-separated test patterns.

More specifically, R, G,
The amount of misconvergence of a color CRT in which a plurality of phosphors of each color of B are applied in a predetermined arrangement relationship is R,
G and B phosphors are irradiated with electron beams at substantially the same level to display a predetermined test pattern in white on a color CRT,
The test pattern is photographed, and is calculated using image data of the test pattern in a predetermined measurement area set in the photographed image.

The spectral sensitivity characteristic of an area that does not include the area where the measurement area of the imaging surface of the entire imaging system is set, for example, the area having a maximum or minimum sensitivity in the G color area is determined. In the case of, the image data of the test pattern of G color is separated by extracting the image data of the maximum or minimum level from the image data in the color determination area.

By extracting image data of a predetermined output level located on the left side of the image data of the maximum or minimum level from the arrangement relationship of RGB, the image data of the test pattern of R color is separated, and By extracting image data of a predetermined output level located on the right side of the image data of the minimum level, the image data of the test pattern of B color is separated.

Also, R, G, B separated in the color discrimination area
The image data of the test pattern in the measurement area is determined based on the position of the image data of each phosphor color and the arrangement relationship of the phosphor colors to determine which phosphor color has been emitted. It is separated into image data of each phosphor color. Then, a misconvergence amount, which is a shift amount between the test patterns of the respective colors, is calculated using the image data of the test patterns of the respective colors R, G, and B that have been color-separated.

Further, it is preferable that the optical filter is provided on an imaging surface of the imaging means.

According to the above configuration, since the optical filter is integrally provided on the image pickup surface of the image pickup means, the optical filter is easily and accurately arranged so that the spectral sensitivity characteristics in the image pickup surface have desired characteristics. Can be set up. Further, the size of the image pickup system is reduced as compared with the case where the optical filter is provided separately from the image pickup means.

[0041]

FIG. 1 is a diagram showing a configuration of a misconvergence measuring system using a misconvergence measuring apparatus according to the present invention. FIG. 2 is a block diagram of the misconvergence measurement system.

The misconvergence measurement system includes a color CRT 3 to be measured, a signal generator 2 for generating a video signal for displaying a test pattern (cross hatch pattern in the present embodiment) for misconvergence measurement on the color CRT 3, and a color. It comprises a misconvergence measuring device 1 which photographs a test pattern displayed on the CRT 3 and measures a misconvergence amount using the photographed image.

The color CRT 3 is an electromagnetic deflection type color CRT.
As shown in FIG. 3, a color CRT 31 for displaying an image and a drive control circuit 32 for controlling the driving of the color CRT 31 are provided. The color CRT 31 is shown in FIG.
R (red), G (green), and B stripes regularly arranged in the horizontal direction on the back surface of the face plate as shown in FIG.
Phosphor F _R, F _G, phosphor screen 311 by applying a F _B (blue)
Are formed. Further, a grid-type aperture grill 312 is provided at a predetermined interval in front of the fluorescent screen 311 in the color cathode-ray tube 31. In the electron gun mount 313, three electron guns 314 are provided corresponding to the respective colors of R, G, and B, and a deflection yoke 315 is provided outside the tip of the electron gun mount 313.

The drive control circuit 32 controls the electron gun 314 and the deflection yoke 3 based on the video signal input from the signal generator 2.
By driving the electron gun 15, the electron gun 314 emits an electron beam Bm corresponding to each color of R, G, and B, and the fluorescent screen 311 is raster-scanned to display a test pattern on the color CRT 31.

The signal generator 2 comprises a video generator, converts an image of the test pattern into a video signal, and outputs the video signal to the color CRT 3. In the convergence measurement, a video signal of a cross hatch pattern is output from the signal generator 2 to the color CRT 3, and the color CRT 3 is shown in FIG.
A cross hatch pattern 4 as shown in FIG.

The misconvergence measuring device 1 comprises an imaging device 11 for photographing a test pattern for misconvergence measurement displayed on the color CRT 3 and a measuring device main body 12 for calculating the amount of misconvergence using the photographed image. I have. Imaging device 11 and signal generator 2
Are connected to the measurement control main body 12 by cables.

The image pickup device 11 is composed of a video camera provided with an image pickup device composed of a CCD area sensor. The imaging apparatus 11 has a spectral transmittance characteristic (500 in FIG. 6) that suppresses transmission in a wavelength region other than the G color as shown in FIG.
An optical filter 112 having a transmittance in a wavelength region other than ６００600 nm is greatly reduced. An imaging lens 113 having a constant optical magnification for forming an optical image of the test pattern is provided (see FIG. 7).

In the present embodiment, the optical filter 112 is provided on the entire image pickup surface of the CCD area sensor 111. The optical filter 112 has an image pickup function corresponding to a measurement area (described later) set in a photographed image on the image pickup surface. Since it is provided to change the spectral sensitivity characteristic of the region, it may be provided only at a portion of the imaging surface corresponding to at least the measurement region on the imaging surface.

In this embodiment, a CCD is used as a monochrome area sensor. However, another type of area sensor such as a MOS area sensor may be used.

As shown in FIG. 8, the CCD area sensor 111 is composed of, for example, (horizontal 768.times.vertical 484) pixels g arranged in a two-dimensional matrix. 0.4 μm × 9.8 μm vertical)
It has the size of The imaging device 11 can perform exposure control according to an arbitrary shutter speed by controlling the charge accumulation time of the CCD area sensor 111.

The CCD area sensor 111 corresponds to FIG.
Have spectral sensitivity characteristics as shown in FIG. Accordingly, the spectral sensitivity characteristic of the entire imaging device 11 is obtained by multiplying the spectral sensitivity characteristic of the CCD area sensor 111 shown in FIG. 20 by the spectral transmittance characteristic of the optical filter 112 shown in FIG. As shown, the sensitivity is high in the wavelength region of the color G, and the sensitivity is suppressed in the other wavelength regions. Therefore, the sensitivity ratio between the R, G, and B color components with respect to the color temperature of the test pattern displayed on the color CRT 3 is as shown in Table 2.

[0052]

[Table 2]

An image signal obtained by photographing a test pattern is not output from the imaging device 11 after being separated into R, G, and B color components. However, when the display temperature of the test pattern changes as shown in Table 2, In addition, the sensitivity ratio among the R, G, and B color components is always such that the G color component is high, and among the image signals output from the imaging device 11, the output level of the pixel g that receives light emitted from the G phosphor is reduced. Since the output level becomes higher than the output level of the pixel g that has received the light emitted from the R and B phosphors, the image of the G color component can be separated by detecting the image signal having the highest output level from the captured image of the test pattern. I can do it.

The measuring device main body 12 displays a predetermined test pattern (cross hatch pattern) required for the misconvergence measurement on the color CRT 3, causes the imaging device 11 to photograph an image of the test pattern, and uses the photographed image. Measure the amount of misconvergence.

That is, the measuring device main unit 12 inputs the video signal of the cross hatch pattern from the signal generator 2 to the color CRT 3, and as shown in FIG.
While displaying the cross hatch pattern 4 on the color CRT 3, the driving of the exposure operation (photographing operation) of the imaging device 11 is controlled to photograph the cross hatch pattern 4 displayed on the color CRT 3.

In FIG. 5A, an area 5 is an area to be photographed by the imaging device 11 to measure the amount of misconvergence, but at least a cross-section is provided so that the amount of misconvergence can be measured in both the vertical and horizontal directions. It is set to include one point. When the cross hatch pattern 4 is photographed by the imaging device 11, FIG.
A cross-shaped image as shown in FIG. The vertical misconvergence amount is calculated using the image of the region Q including the horizontal line in the captured image, and the horizontal misconvergence amount is calculated using the image of the region Q ′ including the vertical line in the captured image. Is calculated.

Since the image pickup device 11 is a monochrome image pickup device, the image pickup device 11 outputs a monochrome image signal (a signal having a light receiving level corresponding to the light emission amount of the cross hatch pattern) to the measuring device main body 11.

In the measuring device main body 11, first, the imaging device 1
By extracting the image signal having the highest output level from the monochrome image signals output from 1, the image of the G color component of the crosshatch pattern is separated, and the image signals other than the maximum output level are extracted, The image of the R, B color components of the cross hatch pattern is separated from the arrangement relationship of the RGB phosphors, and the images of the R, G, B color components are extracted as shown in FIGS. . The details of the method of extracting the image signals of the R, G, and B color components from the monochrome image signal will be described later.

Then, R, R in the region Q including the horizontal line 4a
The luminance center of gravity Dr of the horizontal line 4a for each image of the G and B color components
y, Dgy, and Dby are calculated, and a deviation amount ΔDrgy (= | Dr) between the luminance centroids based on any one of the luminance centroids, for example, the luminance centroid Dgy of the G color.
y−Dgy |) and ΔDbgy (= | Dby−Dgy |) are calculated, and these shift amounts ΔDrgy and ΔDbgy are
_Are converted into deviation amounts ΔD _RGY and ΔD _BGY on the fluorescent screen, and are calculated as the amount of _{misconvergence in} the vertical direction.

The shift amounts ΔD _RGY and ΔD _BGY on the fluorescent screen of the color CRT 3 are calculated from the photographing magnification β of the imaging lens and the shift amounts ΔDrgy and ΔDbgy by the following arithmetic expressions.

ΔD _RGY = ΔDrgy / β (1) ΔD _BGY = ΔDbgy / β (2) Also, for each image of the R, G, and B color components of the area Q ′ including the vertical line 4b, Luminance center of gravity Drx, Dgx, Dbx
Is calculated, and the shift amount ΔDrgx (= | Drx−Dgx) between the luminance centroids with respect to the luminance centroid Dgx of the G color.
|) And ΔDbgx (= | Dbx−Dgx |) are calculated, and these deviation amounts ΔDrgx and ΔDbgx are converted into deviation amounts ΔD _RGX and ΔD _BGX on the fluorescent screen of the color CRT 3 by the following arithmetic expressions, and the _results in the horizontal direction are obtained. It is calculated as the amount of misconvergence.

ΔD _RGX = ΔDrgx / β (3) _ΔDBGX = ΔDbgx / β (4) In the present embodiment, the deviation amount of the luminance center of gravity of each color of the horizontal line 4a and the vertical line 4b in the cross hatch pattern is mistaken. Although the convergence amount is used, the center position of the line width of the horizontal line 4a and the vertical line 4b of each color, the position of the peak level in the line, or the cross-sectional shape of the light emission level of the horizontal line 4a and the vertical line 4b is approximated by a polynomial function. Then, the position of the peak level of the function may be set as the line position of the horizontal line 4a and the vertical line 4b, and the shift amount of these positions may be set as the misconvergence amount.

As shown in FIG. 2, the measuring device main body 12 includes an amplifier 121, an A / D converter 122, and a VRAM (video RA).
M) 123, RAM (Random Access Memory) 124,
A read only memory (ROM) 125, an input unit 126, a display unit 127, and a control unit 128 are provided.

The amplifier 121 amplifies an image signal (a group of light receiving signals output from each pixel of the CCD) output from the imaging device 11 to a predetermined level. The A / D converter 122 converts the image signal (analog signal) into, for example, 10
The digital signal is converted into a bit digital signal (hereinafter, this digital signal is referred to as image data). VRAM12
Reference numeral 3 denotes a memory for storing image data output from the A / D converter 122. The ROM 125 is a memory in which a control program for displaying a test pattern for misconvergence measurement, photographing the test pattern, performing image processing of a photographed image, and the like is stored. Also, RAM
Reference numeral 124 denotes a memory for the control unit 127 to perform predetermined arithmetic processing according to a control program.

The input unit 126 is used to input data such as pixel pitch of the CCD area sensor and phosphor pitch of the color CRT 3 and information required for misconvergence measurement such as misconvergence measurement instruction. Display 12
Reference numeral 7 denotes an LCD or the like for displaying a measurement result.

The control unit 128 performs processing such as display control of the cross hatch pattern on the color CRT 3, control of photographing of the cross hatch pattern by the imaging device 11, calculation of the amount of misconvergence using the photographed image, and the like.

Next, the measurement processing of the amount of misconvergence will be specifically described with reference to the flowchart shown in FIG.

The measurement of the amount of misconvergence is started by arranging the imaging device 11 to face a predetermined measurement area 5 on the display surface of the color CRT 3 as shown in FIG.

First, a video signal for displaying the cross hatch pattern in white is output from the signal generator 2 to the color CRT 3, and the cross hatch pattern 4 is displayed in white on the entire display surface of the color CRT 3 as shown in FIG. (# 1). When the cross hatch pattern 4 is displayed in white on the entire display surface of the color CRT 3, the CCD of the imaging device 11
A cross-shaped crosshatch pattern image including one cross point is formed on the area sensor 111.

Cross hatch pattern 4 on color CRT 3
When the misconvergence measurement instruction is input from the input unit 126 in a state where is displayed in white, the cross hatch pattern 4 displayed in white is captured by the imaging device 111 (# 2). In this photographing process, after adjusting the force of the imaging lens, the CCR area sensor 111 is exposed for a predetermined time (accumulates electric charges), and an image of the cross hatch pattern 4 is captured.

When the photographing of the cross hatch pattern 4 is completed, an image signal is output from the imaging device 11 to the measuring device main body 12, and the level of the image signal is adjusted by the amplifier 121 in the measuring device main body 12, and the A / D converter is used. After being converted into a digital image signal (image data) at 122, the VRAM
123 is temporarily stored.

Subsequently, using the image data stored in the VRAM 123, the horizontal line 4a of the crosshatch pattern 4 is used.
And the position of the vertical line 4b are detected (# 3).

The position of the horizontal line 4a is determined by, for example, integrating the light receiving levels stored corresponding to the respective pixel positions of the VRAM 123 in the horizontal direction (x direction in FIG. 11) as shown in FIG. This is detected by calculating the output distribution P in the y direction (11 in FIG. 11) and calculating the pixel position yp in the y direction that is the maximum output of the output distribution P.

Similarly to the case of the horizontal line 4a, the position of the vertical line 4b is calculated by integrating the light receiving levels stored corresponding to the respective pixel positions of the VRAM 123 in the vertical direction (y direction in FIG. 11). This is detected by calculating an output distribution P ′ in the x direction (in FIG. 11) and calculating a pixel position xp in the x direction that is the maximum output of the output distribution P ′.

Since the position detection of the horizontal line 4a and the vertical line 4b is for determining the measurement areas Q and Q 'of the amount of misconvergence in the vertical and horizontal directions, the accuracy of the detection position is particularly problematic. Not done. Therefore, an arbitrary position of the mountain-shaped output distributions P and P ′ in FIG. 11 may be set as the position of the horizontal line 4a or the vertical line 4b.

In this embodiment, in order to detect the position of the horizontal line 4a or the vertical line 4b at a high speed, the light receiving levels of all the pixels are integrated to create an output distribution, and the maximum distribution position yp,
xp is the position of the horizontal line 4a or the vertical line 4b.

When the positions of the horizontal line 4a and the vertical line 4b are detected, a rectangular area Q for calculating the vertical misconvergence amount of the horizontal line 4a is subsequently obtained.
(Hereinafter, referred to as a vertical measurement area Q) is determined, and a rectangular area Q ′ (hereinafter, referred to as a horizontal measurement area Q ′) for calculating a horizontal misconvergence amount for the vertical line 4b is determined. (# 4).

The vertical measurement area Q is used to accurately measure the vertical misconvergence amounts ΔDrgy and ΔDbgy.
An area that does not approach the vertical line 4b but includes only the horizontal line 4a is surely selected. Similarly, in the horizontal measurement area Q ′, an area that does not approach the horizontal line 4a and includes only the vertical line 4b is surely selected in order to accurately measure the horizontal misconvergence amounts ΔDrgx and ΔDbgx.

In this embodiment, the vertical measurement area Q is set at the longer middle part of the horizontal line 4a, and the horizontal measurement area Q 'is set at the longer middle part of the vertical line 4b. Assuming that the upper left corner of the storage area of the VRAM 123 is the origin of the xy coordinates, the xy coordinates are taken in pixel pitch units, and the number of pixels of the CCD area sensor 111 is n (horizontal) × m (vertical), as shown in FIG. The horizontal × vertical size of the captured image stored in the VRAM 123 is n × m. Step # 3
Is the position of the horizontal line 4a detected in step y, and the vertical line 4b is
Is defined as xp, the vertical measurement area Q is xp + (n−
xp) / 2, and the horizontal measurement area Q 'is yp + (m
-Yp) / 2.

Note that the size of the vertical measurement area Q is L
If (horizontal) × H (vertical), the vertical dimension H is the horizontal line 4a
(For example, an integral multiple of the peak width of the output distribution), and the lateral dimension L is set to the CCD area sensor 111.
Is set to an integral multiple (five times in FIG. 11) of the same-color phosphor image pitch in the phosphor image formed on the image pickup surface of FIG.

Also, the size of the horizontal measurement area Q ′ is L ′
If (horizontal) × H ′ (vertical), the horizontal dimension L ′ is the vertical line 4
b is set to a dimension (for example, an integral multiple of the width of the peak of the output distribution), and the vertical dimension H ′ is set to an appropriate dimension when the phosphor of the color CRT 3 is an aperture grill type. In the case of, the pitch is set to an integral multiple of the same color phosphor image pitch in the phosphor image formed on the imaging surface of the CCD area sensor 111.

The vertical measurement area Q and the horizontal measurement area Q ′
Is set, the vertical _{misconvergence} amounts ΔD _RGY and ΔD _BGY are calculated using the image data in the vertical measurement area Q.
_Are calculated (# 5 to # 8), and the lateral _{misconvergence} amounts ΔD _RGX and ΔD _BGX are calculated using the image data in the horizontal measurement area Q ′ (# 9 to # 1).
2).

The misconvergence amount Δ in the vertical direction
In the calculation of D _RGY and ΔD _BGY , first, of the image data constituting the horizontal line 4a in the vertical measurement area Q, image data that has received light emission of the G phosphor is extracted (# 5).
That is, the image of the G color component is separated from the image of the horizontal line 4a in the vertical measurement area Q.

Subsequently, the light emission position of the G phosphor and R, G,
From the arrangement relationship of B, the image data that has received the light emission of the R and B phosphors is respectively extracted (# 6). That is, the image of the R and B color components is separated from the image of the horizontal line 4a in the vertical measurement area Q.

Aperture grill type color CRT
Thus, even if misconvergence occurs in the vertical direction, the electron energy applied to the phosphors of R, G, and B colors is the same, so that the display position of the horizontal line 4a in the display screen changes in the y direction. However, the ratio of the light emission amounts of the R, G, and B colors does not change. Therefore, in the case of white display, the ratio of the light emission amounts is R: G: B ≒ 1: 1: 1.

On the other hand, since the spectral characteristics of the imaging device 11 are as shown in FIG. 9 as described above, among the image signals output from the imaging device 11, the image signal having the maximum output level is G
Of the phosphor. For example, color C
The color temperature of the crosshatch pattern displayed on RT3 is 6
In the case of 500K, as shown in Table 2, the ratio of the light receiving levels is R: G: B ≒ 0.52: 1: 0.52. Since the light receiving level is about twice as high as the light receiving light, the image of the horizontal line 4a due to the light emission of the G phosphor can be extracted by extracting the image data having the maximum light receiving level.

Therefore, in the present embodiment, even when the color temperature of the cross hatch pattern displayed on the color CRT 3 changes, the image of the horizontal line 4a due to the emission of the G phosphor can be reliably extracted. The image data in the vertical measurement area Q is integrated in the y direction, and the portion of the maximum output level is extracted as an image of the horizontal line 4a due to the emission of the G phosphor from the integration result (output distribution). .

FIG. 12 is a diagram showing an output distribution obtained by integrating image data in the vertical measurement area Q in the y direction.
In the figure, since the portion having the maximum output level is the portion receiving the emission of the G phosphor, the portion indicated by the bar graph with the diagonal line to the lower right (hereinafter referred to as the diagonal bar portion) is the G fluorescence. This is the part that receives the light emitted from the body. For an aperture grill type color CRT, R,
Since the striped phosphors of G and B are repeatedly provided in this order in the horizontal direction, the portion indicated by a bar graph with a vertical line to the left of the hatched bar portion (hereinafter referred to as a vertical bar portion) is R. A portion indicated by a bar graph with a horizontal line on the right side of the hatched bar portion (hereinafter, referred to as a horizontal bar portion) is a portion that has received the light emission of the phosphor B.

Therefore, by extracting the image data of the portion having the maximum output level from the output distribution shown in FIG. 12, the image of the horizontal line 4a of the G color component in the vertical measurement area Q is extracted. Further, the light emission positions of the R and B phosphors are also determined from the positions of the hatched bar portions and the arrangement relationship of R, G, and B, and the image data of the vertical bar portions is extracted, thereby obtaining the vertical measurement area Q. Then, the image of the horizontal line 4a of the R color component is extracted, and the image of the horizontal line 4a of the B color component in the vertical measurement region Q is extracted by extracting the image data of the horizontal bar portion.

Subsequently, the luminance barycenters Dry and D are determined for the image of the horizontal line 4a of the extracted R, G and B color components, respectively.
gy and Dby are calculated (# 7). That is, the extracted image data of each color of R, G, and B is integrated in the x-direction, and FIG.
3 (a), 3 (b), 3 (c), output distributions P _R , P _G ,
Create a P _B, the center of gravity of the power distribution for each color component luminance center Dry, dGy, is calculated as DBY. Then, the vertical _{misconvergence} amounts ΔD _RGY and ΔD _BGY are calculated by the above equations (1) and (2) using the luminance centroids Dry, Dgy and Dby and the imaging magnification β of the imaging lens (#)
8).

Misconvergence amount Δ in the horizontal direction
The calculation of D _RGX and ΔD _BGX is performed in the same procedure as the vertical _{misconvergence} amounts ΔD _RGY and ΔD _BGY . That is, of the image data constituting the vertical line 4b in the horizontal measurement area Q ', image data that has received light emission of the G phosphor is extracted (# 9). From the arrangement relationship of R, G, and B, image data that has received light emission of the R and B phosphors is respectively extracted (# 10).

[0092] When the misconvergence in the horizontal direction is generated R, G, phosphor F _R colors of B, F _G, phosphor be an electronic energy irradiated in F _B is the same F _R,
F _G, the shift in irradiated point of the electron beam Bm for F _B are different between the color components, among the image signals spectral characteristic of the imaging device 11 is outputted from the imaging device 11 be as shown in FIG. 9, The one with the highest output level is not always the one that receives the light emission of the G phosphor.

For this reason, in the misconvergence measurement in the horizontal direction, the image data of the entire photographing area is integrated in the y direction, and the light emission position of the G phosphor is calculated from the integration result (output distribution). That is, when the image data of the entire photographing area is integrated in the y direction, the output distribution becomes as shown in FIG. 14, and a distribution in which the output changes in accordance with the presence or absence of light emission of the phosphor in the photographing area is obtained.

Therefore, in the output distribution shown in FIG.
If the numbers 0, 1, 2,... Are assigned to the respective light-emitting portions from the left end, in the vertical measurement region Q, the light-emitting portion of the G phosphor in the region Q is known. By calculating which light emission position in the output distribution shown in FIG. 14 corresponds to the portion, the light emission position of the G phosphor in the entire imaging region is calculated. In the example of FIG. 14, the hatched bar portion is located at the position of the number 3k (k = 0, 1, 2,...), So that the light emission position of the G phosphor is determined to be the position of the number 3k. The light emission position of the R phosphor is determined to be the position of number 3k + 2 (k = 0, 1, 2,...) From the arrangement relationship of R, G, and B, and the light emission position of the phosphor of B is numbered. It is determined that the position is 3k + 1 (k = 0, 1, 2,...).

Therefore, the image of the vertical line 4b of the G color component is extracted by extracting the image data at the position of the number 3k included in the vertical measurement area Q, and the image data of the position of the number 3k + 2 is extracted. Thus, the image of the vertical line 4b of the R color component is extracted, and the image data at the position of the number 3k + 1 is extracted to obtain the vertical line 4b of the B color component.
The image of b is extracted.

Subsequently, the luminance barycenters Drx and Dx of the image of the vertical line 4b of the extracted R, G and B color components are respectively set.
gx and Dbx are calculated (# 11). That is, the extracted image data of each color of R, G, B is integrated in the y direction to create an output distribution as shown in FIGS. 15 (a), 15 (b), and 15 (c). The center of gravity is the luminance center of gravity Drx, Dg
x, Dbx. Then, these luminance centroids D
Using the values of rx, Dgx, Dbx and the imaging magnification β of the imaging lens, the lateral _{misconvergence} amounts ΔD _RGX and ΔD _BGX are calculated by the above equations (3) and (4) (# 12).

Then, the misconvergence amount Δ
When D _RGX , ΔD _BGX, ΔD _RGY , and ΔD _BGY are calculated, the calculation results are displayed on the display unit 127 (# 13), and the measurement process ends.

As described above, the misconvergence measuring device 1 is configured to output the cross hatch pattern 4 of the image signal output from the imaging device 11 irrespective of the color temperature of the cross hatch pattern 4 displayed on the color CRT 3.
An optical element having a required filter characteristic for the monochrome CCD area sensor 111 so that the signal level of the image signal that has received the light emission of the G phosphor is higher than the signal level of the image signal that has received the light emission of the R and B phosphors. Filter 1
Since the imaging element is provided by providing 12, the amount of misconvergence can be measured at high speed, stably regardless of the display temperature, and with high accuracy.

In the above embodiment, the optical filter 112 is provided on the entire image pickup surface of the CCD area sensor 111. However, as shown in FIG.
It may be provided only in an area where the vertical measurement area Q and the horizontal measurement area Q ′ of the imaging surface of the CD area sensor 111 are not set (in FIG. 16, the periphery of the imaging surface). Note that the width W of the optical filter 112 can be appropriately set according to the size of the emission image of the phosphor to be formed.

In the example shown in FIG. 16, the optical filter 112 is provided on the entire peripheral portion B of the imaging surface. However, the optical filter 112 may be provided only on the left and upper peripheral portions B.

When such an image pickup device is used, it is needless to say that only the portion B provided with the optical filter 112 has the spectral sensitivity characteristic shown in FIG. 9, and the other portion A has the spectral sensitivity shown in FIG. Has characteristics.

Therefore, the optical filter 11 is provided on a part of the imaging surface.
In a misconvergence measuring apparatus provided with an image pickup device having an image pickup device provided with R, G, and B phosphors, an image signal output from a pixel provided with an optical filter 112 in a captured image is used. The light emission position is calculated, and based on the light emission position of the phosphor, the image of the horizontal line 4a in the vertical measurement region Q and the vertical line 4 in the horizontal measurement region Q 'are obtained.
The color separation of the image b is performed.

FIG. 17 shows an optical filter 1 on a part of the imaging surface.
12 is a flowchart showing a procedure for measuring the amount of misconvergence in a misconvergence measuring device provided with an imaging device having an imaging element provided with an imaging device 12;

In FIG. 17, steps # 21 to # 24
Is a process for displaying a cross hatch pattern in white on the color CRT 3, capturing the display pattern with the imaging device 11, and determining the vertical measurement region Q and the horizontal measurement region Q ′ for the captured image. This is the same as the processing contents of steps # 1 to # 4 in the flowchart shown.

Steps # 28 and # 29 are processes for calculating the _{misconvergence} amounts ΔD _RGY and ΔD _BGY in the vertical direction. Steps # 7 and # 8 in the flowchart shown in FIG.
Steps # 30 and # 31 are processes for calculating the _{misconvergence} amounts ΔD _RGX and ΔD _BGX in the horizontal direction, and are the same as those in step # in the flowchart shown in FIG.
Steps # 32 and # 12 are the same as the processing contents
_{Are misconvergence} amounts ΔD _RGX , ΔD _BGX , Δ
In the process of displaying D _RGY and ΔD _BGY on the display unit 126, FIG.
0 is the same as the processing in step # 13 of the flowchart shown in FIG.

As described above, the flow chart shown in FIG. 17 differs from the flow chart shown in FIG. 10 in the processing for separating the captured images in steps # 26 to # 27 into R, G, and B color component images. Now, the color separation processing of a captured image will be described.

FIG. 18 is a diagram showing a photographed image of a cross hatch pattern stored in the VRAM as an image of R, G, and B color components.

In the figure, the region B ′ is the optical filter 1
Reference numeral 12 denotes a storage area for the image data output from the pixels provided. An area A ′ is a storage area for image data output from pixels where the optical filter 112 is not provided, and the image of the horizontal line 4a and the vertical line 4b included in the area A ′ is Measurement area Q
And a horizontal measurement area Q ′.

In step # 25, a rectangular area R (hereinafter referred to as a color determination area R) for determining the light emission positions of the phosphors of R, G, and B in the area B 'is determined. The color determination area R is set to an area including the image of the horizontal line 4a in the area B '. Since the position of the horizontal line 4a in the y direction is calculated in step # 23, the position of the color determination region R is determined from the calculation result and the region B '.

The horizontal dimension L ″ of the color determination area R is set to be substantially the same as the width W ′ of the area B ′.
Since the width W of 2 is known, the area (peripheral storage area) B ′ of the storage area of the VRAM 123 in which the image data output from the pixel provided with the optical filter 112 is stored is known in advance. . Therefore, the horizontal dimension L ″ of the color determination area R is set based on the width H ′ of the area B ′.

On the other hand, the vertical dimension H ″ of the color determination area R is set to be substantially the same as the vertical dimension H of the vertical measurement area Q. Since the vertical dimension H of the vertical measurement area Q is set in step # 24, The vertical dimension H ″ of the color determination area R is set based on this set value.

When the color discrimination area R is set, subsequently, in this color discrimination area R, the portions of the R, G, and B phosphors that emit light are discriminated (# 26). In the measurement area Q and the lateral measurement area Q ′, R,
The image of the horizontal line 4a and the vertical line 20a of the G and B color components is extracted (# 27). This step # 26, # 2
7 is performed by a method similar to the processing in steps # 9 and # 10 in the flowchart of FIG.

That is, the image data of the entire photographing area is defined as y
The light emission positions of the R, G, and B phosphors in the color determination region R are calculated from the integration result (output distribution),
From this calculation result and the arrangement relationship of RGB, the vertical measurement area Q
In addition, the emission positions of the R, G, and B phosphors are calculated in the horizontal measurement region Q ′, and based on the calculation result, the image of the horizontal line 4a and the vertical line 20a of each color component is extracted.

FIG. 19 shows an output distribution obtained by integrating the image data of the entire photographing area in the y direction in the photographed image shown in FIG. In the color discrimination region R, the level at which the light emission of the G phosphor is received is about twice as high as the level at which the light emission of the R and B phosphors is received. The light emitting position of the phosphor can be known.

That is, in the output distribution shown in FIG. 19, if the numbers 0, 1, 2,... Are assigned to the respective light emitting portions from the left end, it is possible to know the order of the light emitting portion of the G phosphor. In the example shown in the figure, since the hatched bar portion having the highest light receiving level is located at the position of number 3k (k = 0, 1, 2,...), The light emission position of the G phosphor is assumed to be the position of number 3k. Is determined. The light emission position of the R phosphor is determined to be the position of number 3k + 2 (k = 0, 1, 2,...) From the arrangement relationship of R, G, and B, and the light emission position of the phosphor of B is numbered. It is determined that the position is 3k + 1 (k = 0, 1, 2,...) (# 26).

Therefore, the image of the vertical line 4b of the G color component is extracted by extracting the image data at the position of the number 3k included in the vertical measurement area Q, and the image data at the position of the number 3k + 2 is extracted. As a result, the image of the vertical line 4b of the R color component is extracted, and the image data at the position of the number 3k + 1 is extracted to obtain the vertical line 4b of the B color component.
The image of b is extracted (# 27).

As described above, the misconvergence measuring apparatus provided with the image pickup device having the image pickup device provided with the optical filter 112 on a part of the image pickup surface also has the image pickup device provided with the image pickup device provided with the optical filter 112 on the entire image pickup surface. Image of the horizontal line 4a in the vertical measurement area Q and the horizontal measurement area Q 'as in the misconvergence measurement apparatus having
Color separation of the image of the vertical line 4b in
The vertical _{misconvergence} amounts ΔD _RGY and ΔD _BGY are calculated using the image of the horizontal line 4a of the G and B color components,
The horizontal _{misconvergence} amounts ΔD _RGX and ΔD _BGX are calculated using the image of the vertical line 4b of the R, G, and B color components.

In this embodiment, the optical filter 112 is not provided in the portion where the vertical measurement area Q and the horizontal measurement area Q ′ are set in the photographing screen.
12 (that is, the S / N of the image data for calculating the misconvergence amount).
There is an advantage that the measurement accuracy is improved as compared with the case where the optical filter 112 is provided on the entire imaging surface.

Needless to say, a color discrimination area is set to an area not including an area where the above-described measurement area is set in an image picked up by an image pickup apparatus having an image pickup element provided with an optical filter 112 over the entire image pickup surface. It is also possible to perform color separation of the image data in the measurement region from the color separation result and the arrangement relationship of the phosphor colors using a method of setting and color separation of the image data in the color determination region.

In the above embodiment, an aperture grill type color CRT has been described as an example. However, the present invention can be applied to misconvergence measurement of a dot mask type or slot mask type color CRT.

In the above embodiment, the optical filter 11
2 has a spectral transmittance characteristic that suppresses transmission in a wavelength region other than the G color, that is, an example in which the spectral sensitivity characteristic of the imaging device 11 is maximized only near the G color region. However, the spectral transmittance of the optical filter 112 may be such that the spectral sensitivity characteristic of the imaging device 11 becomes maximum only in the vicinity of a color region such as R and B.

On the contrary, when the optical filter 112 is in the R color area,
Having a spectral transmittance characteristic that suppresses only transmission of the color region or the color region of B, that is, the spectral sensitivity characteristic of the imaging device 11 is only in the vicinity of the R color region, the G color region, or the B color region. May be minimized. When the optical filter 112 having such a spectral transmittance characteristic is used, the level of a portion of the captured image that receives light emitted from the phosphor of any of the R, G, and B colors is minimized. By extracting the image signal of the minimum level, one of the R, G, and B colors can be determined, and the image signals of the other colors can be extracted from the RGB arrangement relationship.

In short, as for the spectral transmittance characteristic of the optical filter 112, the spectral sensitivity characteristic of the image pickup device 11 is the color C in relation to the spectral sensitivity characteristic of the CCD area sensor 111.
Spectral transmittance characteristics such that a maximum or minimum sensitivity occurs in any one of the phosphor color regions of the phosphor included in RT3, and a light emitting portion of one phosphor color can be determined from the maximum or minimum level of a captured image. Various types of optical filters such as a band-pass filter, a high-pass filter, and a low-pass filter can be employed as long as they satisfy the above-mentioned requirements.

Although the optical filter 112 is provided on the imaging surface of the CCD area sensor 111 in the above embodiment, the optical image of the test pattern is
The optical filter 112 is arranged at an appropriate position inside or outside the optical system leading to the image pickup surface of the CCD area sensor 1.
The spectral sensitivity characteristics of the entire or a part of the imaging surface of No. 11 are represented by R,
Either G or B color may be detected.

Further, in the above embodiment, the area sensor is used as the image sensor, but a line sensor may be used. In this case, one line sensor is arranged in each of the y direction and the x direction, and the image of the horizontal line 4a and the vertical line 4b of the cross hatch pattern 4 is captured by each line sensor, and the images are measured. By performing the same image processing as described above for the image ', it is possible to calculate the vertical _{misconvergence} amounts ΔD _RGY and ΔD _BGY and the horizontal _{misconvergence} amounts ΔD _RGX and ΔD _BGX .

[0126]

As described above, according to the present invention,
An optical filter is provided on an optical path of an optical system that guides a light image of a test pattern to an imaging surface of the imaging unit while using a monochrome imaging unit, and the spectral sensitivity characteristic of the imaging surface of the imaging unit is any one of phosphor color regions. In order to obtain the characteristic having the maximum or minimum sensitivity, the image data of the maximum or minimum level is extracted from the image data constituting the photographed image of the test pattern, and the position of the image data and the color of the fluorescent substance are extracted. Since the image data obtained by receiving the light emission of the phosphor of each color is separated from the arrangement relationship, the color C
Even when the color temperature of the test pattern displayed on the RT changes, the image of each phosphor color can be reliably separated from the monochrome photographed image, and the amount of misconvergence can be quickly measured with high accuracy. 1-3).

Further, according to the present invention, a monochrome image pickup means is used, and an optical filter is provided on an optical path of an optical system for guiding an optical image of a test pattern to an image pickup surface of the image pickup means. Since the spectral sensitivity characteristic of a portion that does not include the region where the region is set is a characteristic having the maximum or minimum sensitivity in any one of the phosphor color regions, image data for calculating the amount of misconvergence is set. Is not reduced by the optical filter, that is, the S / N of the image data is not reduced, and the measurement accuracy of the amount of misconvergence is further improved (claims 4 and 5).

Further, according to the present invention, since the region not including the region where the measurement region is set is set as the peripheral portion of the captured image, the shape of the optical filter is simplified, and the arrangement of the imaging means with respect to the imaging surface is also possible. It becomes easy (claim 6).

Further, according to the present invention, since the optical filter is provided on the image pickup surface of the image pickup means, the spectral sensitivity characteristics of the entire image pickup system can be easily set to desired characteristics, and the image pickup of the optical filter can be performed. The size of the image pickup system is smaller than that provided separately from the means (claim 7).

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a misconvergence measurement system using a misconvergence measurement device according to the present invention.

FIG. 2 is a block diagram of the misconvergence measurement system.

FIG. 3 is a schematic configuration diagram of a color CRT for measurement.

FIG. 4 is a perspective view of a main part showing a structure of a face plate of an aperture grill type color CRT.

FIG. 5 is a diagram illustrating an example of a cross hatch pattern displayed on a color CRT and a luminance centroid of a captured image of each of R, G, and B color components.

FIG. 6 is a diagram showing a spectral transmittance characteristic of an optical filter.

FIG. 7 is a diagram illustrating a configuration of an imaging optical system of the imaging apparatus.

FIG. 8 is a diagram showing a pixel configuration of a CCD area sensor.

FIG. 9 is a diagram illustrating spectral sensitivity characteristics of the imaging apparatus.

FIG. 10 is a flowchart showing a procedure for measuring the amount of misconvergence by the misconvergence measuring device according to the present invention.

FIG. 11 is a diagram showing a captured image of a cross hatch pattern stored in a VRAM as an image of R, G, and B color components.

FIG. 12 is a diagram showing an output distribution obtained by integrating image data of a vertical measurement area in the y direction.

FIG. 13 is a diagram showing an output distribution for each color component obtained by integrating image data of each color of R, G, and B extracted in the vertical measurement area in the x direction.

14 is a diagram showing an output distribution obtained by integrating image data of the entire photographing area in the y direction in the photographed image of FIG. 11;

FIG. 15 is a diagram illustrating an output distribution for each color component obtained by integrating image data of each color of R, G, and B extracted in the horizontal measurement area in the y direction.

FIG. 16 is a diagram illustrating a modified example of the image sensor in the image capturing apparatus.

FIG. 17 is a flowchart showing a procedure for measuring a misconvergence amount in a misconvergence measuring apparatus provided with an imaging device having an imaging element provided with an optical filter on a part of an imaging surface.

FIG. 18 is a diagram showing a captured image of a cross hatch pattern stored in a VRAM as an image of R, G, and B color components.

19 is a diagram showing an output distribution obtained by integrating image data of the entire photographing area in the y direction with respect to the photographed image of FIG. 18;

FIG. 20 is a diagram illustrating spectral sensitivity characteristics of a monochrome CCD area sensor.

FIG. 21 is a diagram illustrating spectral emission characteristics of R, G, and B phosphors of a color CRT.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Misconvergence measuring device 11 Imaging device 111 CCD area sensor 112 Optical filter 113 Imaging lens (optical system) 12 Measuring device main body 121 Amplifier 122 A / D converter 123 VRAM 124 ROM 125 RAM 126 Input unit 127 Display unit 128 Control unit (Color separation means, calculation means) 2 Signal generator 3 Color CRT 31 Color CRT 32 Drive control circuit 4 Cross hatch pattern 5 Measurement area

Claims (7)

[Claims] 1. A predetermined test pattern displayed by irradiating a plurality of color phosphors coated on a face plate of a color CRT with a predetermined color arrangement with an electron beam, and photographed by monochrome type imaging means. In a misconvergence measuring apparatus for measuring the amount of misconvergence of the color CRT using image data of a test pattern in a measurement area set in the photographed image, an optical image of the test pattern is guided to an imaging surface of the imaging means. One of a plurality of phosphors provided on an optical path of the optical system and having a spectral sensitivity characteristic of an imaging surface of the imaging means,
An optical filter having a spectral transmittance characteristic such that the characteristic has a maximum or minimum sensitivity in the phosphor color region,
A color separation unit that separates image data of a test pattern in the measurement area into image data of a color component of the phosphor based on a level of image data of the captured image and a color arrangement relationship of the phosphor; A misconvergence measuring device, comprising: computing means for computing the amount of misconvergence using image data of a test pattern for each color component separated by the separating means. 2. The optical filter according to claim 1, wherein a spectral sensitivity characteristic of a portion including at least the region where the measurement region is set on the imaging surface of the imaging unit is maximum in any one phosphor color region of a plurality of color phosphors. 2. The misconvergence measuring device according to claim 1, wherein the misconvergence measuring device has a spectral transmittance characteristic such that the characteristic has a minimum sensitivity. 3. The image data of a test pattern in the measurement area based on a level of image data of the test pattern included in the measurement area of the photographed image and a color arrangement relationship of the phosphor. The misconvergence measuring apparatus according to claim 2, wherein the image data is separated into image data of color components of the phosphor. 4. The optical filter according to claim 1, wherein a spectral sensitivity characteristic of at least a portion of the imaging surface of the imaging unit that does not include the measurement region is maximum or minimum in any one phosphor color region of a plurality of color phosphors. 2. The misconvergence measuring device according to claim 1, wherein the device has a spectral transmittance characteristic that provides a characteristic having sensitivity. 5. The color separation means according to claim 1, wherein said image data of a test pattern included in a certain area not including said measurement area of said photographed image is obtained based on a level of said image data and a color arrangement relationship of said phosphor. The image data of the test pattern in the measurement area is separated into the image data of the color component of the phosphor and the image data of the test pattern for each color component and the color arrangement relationship of the phosphor. 5. The misconvergence measuring device according to claim 4, wherein the misconvergence measuring device separates the image data. 6. The misconvergence measuring apparatus according to claim 4, wherein the area not including the area where the measurement area is set is a peripheral area of the captured image. 7. The misconvergence measuring device according to claim 1, wherein the optical filter is provided on an imaging surface of the imaging unit.