JP3116562B2 - CRT measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CRT measuring apparatus for measuring various characteristics of a CRT to be measured, and more particularly, to a CRT equipped with an imaging apparatus whose imaging magnification is automatically set to a predetermined magnification.
It relates to a measuring device.

[0002]

2. Description of the Related Art Conventionally, in order to perform various adjustments such as convergence, purity, and beam width of a color CRT, various adjustment amounts are used by using an image signal obtained by imaging a measurement pattern displayed on a face plate of the color CRT. There is known a CRT measuring apparatus for calculating the following equation.

For example, in convergence adjustment,
CR for measuring the amount of misconvergence of color CRT
T measurement device is known, a measurement pattern of crosshatched the imaging magnification of the imaging lens is displayed by setting the predetermined magnification beta _R to be measured color CRT of the CRT measuring apparatus in JP-A-2-174492 A method for reducing the repetition error of the convergence measurement by imaging is shown.

Here, the predetermined magnification β _R is a horizontal arrangement pitch P of phosphor images on an imaging surface of an imaging device (hereinafter referred to as a CCD) having pixels regularly arranged in a two-dimensional matrix. _CRTX 'is a magnification (hereinafter referred to as an appropriate magnification) that is an integral multiple of the horizontal arrangement pitch _PCCDX of the CCD pixels. For example, when the imaging surface of the CCD is arranged parallel to the display surface (face plate surface) of the color CRT to be measured, the horizontal arrangement pitch P _CRTX of the phosphor images formed on the imaging surface of the CCD. 'Is the color CRT to be measured
From the array pitch P _{CRTX of the} phosphors formed on the back surface of the face plate and the imaging magnification β ₀ of the imaging lens at the time of imaging.
_CRTX ′ = β ₀ · P _CRTX , so that the appropriate magnification β _R is β
_R = K · P _CCDX / P _CRTX (K: an integer proportional constant).

In the above publication, for example, at the time of measurement, a measurement pattern displayed on a color CRT to be measured is imaged, and the spatial frequency of the phosphor image, that is, the phosphor image is obtained from the image signal of the measurement pattern. Horizontal pitch P
_There is suggested a method of automatically setting the imaging magnification of the imaging lens to an appropriate magnification β _R by detecting _CRTX ′.

[0006]

[0007] Meanwhile, 'when detecting the lateral array pitch P _crtX the fluorescent body image' horizontal arrangement pitch P _crtX of fluorescent body image from the image signal obtained by imaging the lateral direction Is detected as the distance between adjacent phosphor images of the same color. For example, since the G phosphor image is composed of discrete pixel data received by the G pixels, the G phosphor image is detected. It is difficult to accurately determine the lateral position. For this reason, there is a large error in the lateral arrangement pitch P _CRTX 'of the phosphor image detected by the phosphor image selected as the arrangement pitch calculation target, and the error is calculated from this arrangement pitch P _CRTX '. In addition, the drive control amount of the photographing lens for setting the appropriate magnification β _R has a large error, which causes an accuracy problem.

In order to solve the above problem, for example, the average value L / N obtained by dividing the distance L between two phosphor images separated by N arrangement pitches by the number N of arrangement pitches is used to calculate the lateral value of the phosphor image. Directional array pitch P _CRTX ′, and the array pitch P _CRTX ′
Although it is conceivable to reduce the calculation error of the above, if the measurement pattern image of the measurement area is a vertical line with a short horizontal dimension,
There are few phosphor images in the horizontal direction included in the vertical line, and the calculation error may not be sufficiently reduced with accuracy.

In order to solve this problem, a region including a large number of phosphor images in the horizontal direction is defined as a region for calculating the array pitch, and the horizontal array pitch P _CRTX ″ of the phosphor images in the region for calculating the array pitch is _used . It is _conceivable to calculate the array pitch P _CRTX ″ as the array pitch P _CRTX ′ in the horizontal direction of the phosphor image in the measurement area. If the arrangement pitch of the phosphor images formed in the regions differs, an error occurs between the arrangement pitch P _CRTX ″ and the arrangement pitch P _CRTX ′, and this error automatically sets the photographing lens to the appropriate magnification β _R. Will be less accurate.

In the above-mentioned Japanese Patent Application Laid-Open No. 2-174492,
The lateral arrangement pitch P _CRTX 'of the phosphor image is detected from the image signal of the captured measurement pattern, and the imaging magnification of the imaging lens is adjusted using the lateral arrangement pitch P _CRTX ' of the _phosphor image. A method for automatically setting the magnification β _R is shown,
No specific method is disclosed, and no description is given of the above problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an improved accuracy in setting an imaging lens to an appropriate magnification.
CRT that can improve measurement accuracy of various measurement quantities
It is an object to provide a measuring device.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an image pickup means in which pixels are regularly arranged in a two-dimensional matrix and photoelectrically converts an optical image to obtain an image signal. Image storage means for storing the image signal obtained by the means, and using the image signal of the measurement area which is a partial area of the image obtained by imaging the measurement pattern image displayed on the CRT to be measured. In a CRT measuring apparatus for measuring various characteristics of a measurement CRT, an imaging lens capable of changing an imaging magnification for guiding the pattern image for measurement to the imaging unit, an aberration characteristic storage unit storing distortion characteristics of the imaging lens, A driving unit for driving the imaging lens to change an imaging magnification, and an array including a light emitting area larger than a light emitting area of the measurement area in a horizontal direction from an image signal stored in the image storage means A first arrangement pitch calculation means for calculating a pitch of the fluorescent body image in pitch calculation area,
Calculating an arrangement pitch of the phosphor images in the measurement area from the arrangement pitch of the phosphor images calculated by the first arrangement pitch calculation means and the distortion characteristics in the measurement area and the arrangement pitch calculation area; 2, an arrangement pitch calculating means, an arrangement pitch of a phosphor image preset in relation to an arrangement pitch of pixels of the imaging means, and a phosphor in a measurement area calculated by the second arrangement pitch calculating means. Magnification correction means for changing the current imaging magnification of the imaging lens from the image arrangement pitch and correcting the imaging magnification with a small repetition error.

[0012]

According to the present invention, an image signal obtained by imaging the measurement pattern displayed on the CRT to be measured is stored in the image storage means. An array pitch calculation area including a light emission area larger than a predetermined measurement area in the horizontal direction is extracted from the image signal stored in the image storage means, and the array pitch of the phosphor images in the array pitch calculation area is calculated. Is done. Further, the arrangement pitch of the phosphor images in the measurement area is calculated from the calculated arrangement pitch of the phosphor images in the arrangement pitch calculation area and the distortion characteristics in the measurement area and the arrangement pitch calculation area.

The present imaging lens is obtained from the calculated arrangement pitch of the phosphor images in the measurement area and the arrangement pitch of the phosphor images preset in relation to the arrangement pitch of the pixels of the imaging means. A correction amount for correcting the imaging magnification of the above to an imaging magnification with a small repeating error is calculated, and the imaging lens is driven based on this correction amount, and the imaging magnification of the imaging lens is automatically set to the imaging magnification with a small repeating error. .

[0014]

FIG. 1 is a schematic diagram showing one embodiment of a CRT measuring apparatus according to the present invention. The CRT measuring device shown in FIG. 1 is a schematic configuration diagram of a convergence measuring device for measuring a misconvergence amount of a color CRT.

In FIG. 1, reference numeral 1 denotes a color cathode ray tube to be measured (hereinafter referred to as a CRT), 2 denotes a driving circuit for controlling the driving of the CRT 1, and 3 denotes a measurement pattern for generating a predetermined measurement pattern, for example, a cross hatch pattern. Pattern generator.

The CRT 1 is, for example, a color CRT of a shadow mask type. As shown in FIG. 2, a face plate 31 for mainly displaying an image, a shadow mask 32, and an electron gun for generating three electron beams 36. And a mount 33. Face plate back 31
In No. 1, phosphors of three colors R (red), G (green) and B (blue) are regularly arranged and printed to form a phosphor surface. Three electron beams 36 radiated from three electron guns 34 provided on an electron gun mount 33 corresponding to R, G, and B are deflected by a deflection yoke 35 to form a fluorescent screen 31.
Scan 1. Each electron beam 36 is applied to the shadow mask 32
Only when the light passes through the hole of the shadow mask 32, the phosphor reaches the fluorescent surface 311 and emits only the phosphor of the corresponding color. Thereby, the face plate 3
1, a predetermined image is displayed.

When performing convergence measurement, a measurement pattern is generated by the measurement pattern generator 3, and information on the measurement pattern is input to the drive circuit 2. The drive circuit 2 performs CR based on the information of the measurement pattern.
Three electron beams 36 are emitted from the electron gun 34 of T1 to emit a predetermined phosphor on the phosphor screen 311 to display a measurement pattern on the face plate 31.

Returning to FIG. 1, the convergence measuring device includes an imaging device 4 and a measuring device main body 5 for calculating a misconvergence amount from an image signal captured by the imaging device 4.
It is composed of

The image pickup device 4 includes a solid-state image pickup device (hereinafter referred to as a CCD) 17 for picking up an image and a CRT
The imaging lens system 12 forms an image of the measurement pattern displayed on the CRT 1 and captures the measurement pattern image displayed on the fluorescent screen 311 of the CRT 1.

The CCD 17 is a photoelectric conversion element (hereinafter, referred to as a photoelectric conversion element).
Pixels) are arranged in a two-dimensional matrix, and for example, as shown in FIG.
This is a single-plate type color imaging device in which G and B color filters are regularly arranged, and color-images the measurement pattern. The image signals picked up by the CCD 17 are R,
The image signals are separated into image signals of each color of G and B and input to the measuring device main body 5. Note that various other elements such as a MOS type element may be used as the color imaging element.

The imaging device 4 includes a focus adjustment mechanism for adjusting the focus of the imaging lens system 12, an aperture changing mechanism for adjusting the aperture value, and a zoom mechanism for adjusting the imaging magnification of the imaging lens system 12. have. The focus of the imaging lens system 12 is adjusted by rotating the focus ring 13, and the aperture value is adjusted by adjusting the aperture ring 14.
Is rotated. The zoom mechanism includes a zoom motor 15 that is a driving source of a zoom lens group of the imaging lens system 12 and a zoom motor driving circuit 16 that controls driving of the zoom motor 15.
The imaging magnification of 2 is adjusted by a control signal from an arithmetic and control circuit 7 in the measuring apparatus main body 5 described later. The adjustment of the imaging magnification will be described later. The switch 18 is a switch for instructing the start of measurement.
The measurement start signal (trigger signal) by 8 is input to the arithmetic and control circuit 7.

Returning to FIG. 1, the measuring device main body 5 includes an image memory circuit 6 for storing an image signal picked up by the image pickup device 4, an operation control circuit 7 for controlling the operation of convergence measurement, and a memory for various operations. 8, a data output device 9 for outputting a calculation result, a data input device 10 for inputting data, and a display device 11 for monitoring an image captured by the imaging device 4.

The image memory circuit 6 includes an A / D conversion circuit 6
It has one and three backup memories 6a, 6b, 6c, and converts an image signal (analog signal) of each color of R, G, B inputted from the imaging device 4 into a digital image by an A / D conversion circuit 61. They are converted into signals (hereinafter, referred to as image data) and temporarily stored in the backup memories 6a, 6b, 6c, respectively. The memory 8 stores a calculation control program for calculating the amount of misconvergence, distortion characteristics of the imaging lens system 12, and other data necessary for calculation, and is input from the calculation result and the data input device 10. Data is also stored.

The arithmetic control circuit 7 is an arithmetic circuit composed of a microprocessor. The arithmetic control circuit 7 controls the operation of the measuring device in accordance with the arithmetic control program stored in the memory 8 and controls the image stored in the image memory circuit 6. A misconvergence amount described later is calculated using the data. The calculated misconvergence amount is stored in the memory 8
And output to the data output device 9. The data input device 10 is for inputting various data to the arithmetic and control circuit 7 from outside. From the data input device 10, for example, the phosphor arrangement pitch P _CRT of the CRT 1, CCD 17 of the pixel array pitch P _CCD of
Information necessary for calculating a misconvergence amount such as an imaging magnification of the imaging lens system 12 is input.

Next, a method of measuring the amount of misconvergence will be briefly described with reference to FIGS.

FIG. 4A shows a white cross hatch pattern 20 for measurement on the entire face plate 31 of the CRT 1.
Is displayed. An imaging area 21 for measuring the amount of misconvergence is an area including a cross point so that the amount of misconvergence can be measured in both the vertical and horizontal directions.

FIG. 4B shows an image of the image pickup area 21. In FIG.
Is an imaging screen of the CCD 17. Reference numeral 23 denotes a measurement area for measuring the amount of misconvergence in the vertical direction, which is a measurement area including a horizontal line portion of the cross hatch pattern 20 (hereinafter, referred to as a horizontal line measurement area).
Reference numeral 24 denotes a measurement area for measuring the amount of misconvergence in the horizontal direction, which is a measurement area including a vertical line portion of the cross hatch pattern 20 (hereinafter, referred to as a vertical line measurement area).

FIG. 4C shows R, G, and B image data in the horizontal line measurement area 23. The hatched portions indicate horizontal line portions of the cross hatch pattern. R _DY , g _DY , and b _DY are R, G, and B, respectively.
Of the horizontal line of each color.

FIG. 4D shows R, G, and B image data in the vertical line measurement area 24. The hatched portions are the vertical line portions of the cross hatch pattern. R _DX , g _DX , and b _DX are R, G, and B, respectively.
Is the luminance barycenter of the vertical line of each color. FIG. 4 (c)
Since (d) shows the image data in the misconvergence state, the luminance centroids of the vertical and horizontal lines of each of the R, G, and B colors are mutually displaced.

The amount of misconvergence is measured according to the following procedure. First, as shown in FIG. 5, the imaging device 4 is set at a predetermined position facing the imaging region 21 of the face plate 31 of the CRT 1. At this time, the surface of the face plate 31 including the imaging region 21 (hereinafter, referred to as a display surface) and the imaging surface of the CCD 17 are parallel to each other, and no tilt angle occurs. Further, XY orthogonal coordinates of the imaging region 21 are set with the center of the region as the coordinate center O, and the X-axis direction is defined as the horizontal direction and the Y-axis direction is defined as the vertical direction.

Returning to FIG. 4, when the power of the convergence measuring device is turned on, the arithmetic control circuit 7 starts executing a predetermined arithmetic control program stored in the memory 8. In addition, the CCD 17 starts the imaging operation, the captured image is displayed on the display device 11, and the measurement of the amount of misconvergence is enabled.

Next, a white crosshatch pattern 20 for convergence measurement is generated by the measurement pattern generator 3 and displayed on the face plate 31 of the CRT 1 via the drive circuit 2 (FIG. 4A). Subsequently, the focus is adjusted by adjusting the focus ring 14 while observing the captured image displayed on the display device 11, and the image of the measurement area 21 is formed on the imaging surface of the CCD 17 (FIG. 4).
(B)).

Next, the switch 18 is operated to instruct the start of measurement. When a measurement start signal is input from the switch 18, first, an image of the measurement pattern 21 is captured by the CCD 17, and the imaging magnification of the current imaging lens system 12 (hereinafter, referred to as current magnification) β ₀ is used by using this image signal. Is calculated. Further, a predetermined magnification (hereinafter referred to as an appropriate magnification) β _R suitable for calculating the calculated current magnification β ₀ and the amount of misconvergence.
These errors are calculated by comparing with the appropriate magnification β _R based on the calculation results.
Automatically set to. The details of the automatic setting processing of the imaging magnification of the imaging lens system 12 will be described later.

Next, when the imaging magnification of the imaging lens system 12 is set to the appropriate magnification β _R , the image of the measurement pattern 20 is captured by the CCD 17 again. This captured image signal is R,
After being separated into three colors of G and B and output to the image memory circuit 6 and subjected to A / D conversion, they are temporarily stored in the backup memories 6a, 6b and 6c, respectively. Then, the arithmetic control circuit 7 calculates the misconvergence amount using the three color image data stored in the backup memories 6a, 6b, 6c. This calculation is performed as follows.

Image data (FIG. 4D) of the vertical line measurement area 24 is extracted from the R, G, and B image data stored in the backup memories 6a, 6b, and 6c, respectively.
The luminance center of gravity r _DX of the vertical line measurement area 24 for each color,
Calculate g _DX and b _DX . For example luminance center r _DX of R is calculated by using the image data in the area indicated by oblique lines of the pattern of R in FIG. 4 (d). Then, the luminance centroids r _DX , g _DX ,
b _DX , any luminance centroid, for example, luminance centroid g _DX
Deviation amount Δd _RGX (= r _DX −g)
_DX ), Δd _BGX (= b _DX −g _DX ), and the misconvergence amounts ΔD _RGX , ΔD _BGX in the lateral direction (X direction) of the CRT ₁ are calculated from the calculation result and the appropriate magnification β _R. The _{misconvergence} amounts ΔD _RGX and ΔD _BGX are calculated by the following _equations (1) and (2).

[0036]

ΔD _RGX = Δd _RGX / β _R = (r _DX −g _DX ) / β _R

[0037]

ΔD _BGX = Δd _BGX / β _R = (r _DX −g _DX ) / β _{R Further} , the _{misconvergence} amounts ΔD _RGY and ΔD _BGY in the vertical direction (Y direction) are calculated in the same manner as described above. I do. That is, the horizontal line measurement area 2 is obtained from the R, G, B image data stored in the backup memories 6a, 6b, 6c.
3 (FIG. 4 (c)) are extracted, and the luminance barycenter r _DY of the horizontal line measurement area 23 for each color is extracted.
Calculate g _DY and b _DY . For example, the luminance center of gravity r _DY of R is calculated using image data of a region indicated by oblique lines of the pattern of R in FIG. Then, for example, luminance center g _DY shift amount between luminance center relative to the _{Δd RGY (= r DY -g DY} ),
ΔD _BGY (= b _DY −g _DY ) is calculated, and the vertical _{misconvergence} amounts ΔD _RGY and ΔD _BGY of the _CRT 1 are calculated from the calculation result and the imaging magnification β _R by the following Expressions 3 and 4.

[0038]

ΔD _RGY = Δd _RGY / β _R = (r _DY −g _DY ) / β _R

[0039]

ΔD _BGY = Δd _BGY / β _R = (r _DY −g _DY ) / β _R and the calculated misconvergence amount ΔD _RGX ,
ΔD _BGX , ΔD _RGY , and ΔD _BGY are stored in the memory 8 and output to the data output device 9 for recording or display. Note that the order of calculating the misconvergence amounts in the horizontal and vertical directions may be any order. Further, the misconvergence amount in one of the directions may be calculated.

The above is the measurement of the amount of misconvergence for one imaging region 21. If necessary, the amount of misconvergence is measured for other imaging regions 21 in the same procedure. In addition, a plurality of imaging devices 4 are attached so as to simultaneously image the plurality of imaging regions 21, and image signals captured by the respective imaging devices 4 are input to the measurement device main body 5, and the above-described imaging regions 21 are respectively described. By performing image signal processing and calculation, the amount of misconvergence at a plurality of locations can be calculated simultaneously.

Next, a process for automatically setting the imaging magnification of the imaging lens system 12 to the appropriate magnification β _R will be described.

Here, prior to the description of the processing, the appropriate magnification β
_R will be described. Since the appropriate magnification β _R is described in detail in Japanese Patent Application Laid-Open No. 2-174492, it will be briefly described here.

When a CCD 17 having pixels arranged in stripes as shown in FIG. 3 receives, for example, a dot-like phosphor image as shown in FIG. 6, the same color as the emission color of the phosphor image is received. Are arranged discretely in the horizontal direction, so that the pixel data forming the phosphor image has a vertical stripe pattern.
For this reason, when the measurement is repeated, the horizontal measurement position of the CCD 17 deviates from the previous measurement position, so that the vertical stripe pattern forming the phosphor image changes, and is calculated using the vertical stripe pattern image data. A repetition error in the luminance center of gravity of the phosphor image occurs, and as a result, the repetition error in measuring the amount of misconvergence in the horizontal direction increases.

The appropriate magnification β _R is such that the horizontal arrangement pitch P _CCDX of the pixels of the CCD 17 is such that the horizontal arrangement pitch P _CRTX ′ of the phosphor images formed on the imaging surface of the CCD 17 is as shown in the following _equation (5 _). At a predetermined magnification for making an integral multiple of the above, the amount of change in the vertical stripe pattern forming the phosphor image due to the above-mentioned displacement of the measurement position of the CCD 17 is reduced, and the repetition error of the luminance center of gravity of the phosphor image is reduced. Is to be reduced.

[0045]

P _CRTX '= K · P _CCDX K; proportionality constant (integer) Therefore, the measurement pattern 2 imaged at the appropriate magnification β _R
By using the image data of 0, the repetition error in the measurement of the amount of misconvergence in the horizontal direction is reduced.

The face plate 3 of the CRT 1
1 between the lateral arrangement pitch P _CRTX of the phosphors formed in FIG. 1 and the lateral arrangement pitch P _CRTX ′ of the phosphor image.
_CRTX ′ = β _R · P _CRTX
When the _crtX 'is substituted into Equation 5, given appropriate magnification beta _R is determined from the horizontal arrangement pitch P _CCDX pixels in the lateral direction arrangement pitch P _crtX and the CCD17 of the phosphor by the following Expression 6 It becomes the magnification of.

[0047]

Β _R = K · P _CCDX / P _CRTX For example, the vertical arrangement pitch P _CRTY of the dot-shaped _phosphor of the CRT ₁ is 310 μm and the horizontal arrangement pitch P _CRTX (=
(3 × P _CRTY ) is 537 μm, the horizontal arrangement pitch P _CCDX of the pixels of the CCD 17 is 25.5 μm, and K = 22, the appropriate magnification β _R is β _R = (22 × 25.5) / 5
37 ≒ 1.045.

[0048] From the proper magnification beta _R or is stored in advance in the memory 8, or the horizontal arrangement pitch P _crtX of phosphor which is input at the time of measurement and the horizontal arrangement pitch P _CCDX of pixels of the CCD17 It is calculated by the above equation (6) and stored in the memory 8.

Normally, in the initial state at the time of measurement, the imaging device 4
Since the imaging magnification of the imaging lens system 12 of the does not match the proper magnification beta _R, calculates the current magnification beta ₀ of the imaging lens system 12 for measurement pattern 20 from the captured image data, the current magnification beta ₀ and the drive amount of the zoom motor 15 for setting the imaging magnification of the imaging lens system 12 to a proper magnification beta _R from the error amount between the proper magnification beta _R is calculated. Then, by driving the zoom motor 15 based on the calculation result, the imaging magnification of the imaging lens system 12 is automatically set to the appropriate magnification β _R.

The current magnification β ₀ of the imaging lens system 12 is
CCD1 is obtained from image data obtained by capturing the measurement pattern 20.
7, the arrangement pitch P _CRTX 'of the phosphor images on the imaging surface is calculated, and the arrangement pitch P _CRTX ' and the arrangement pitch P of the _phosphor are calculated.
It is calculated from _{CRTX by the following equation} (7). This current magnification β
The calculation of ₀ is performed using image data of one color, for example, G image data.

[0051]

Equation 7] _{β 0 = P CRTX '/ P} CRTX Figure 7, the sequence of the fluorescent body image formed on the imaging surface of the CCD17 estimated from the image data of the color of G stored in the image memory circuit 6 It shows the status, R, G,
The symbol B indicates the emission color of each phosphor image. The hatched circle indicates the G phosphor image received by the G pixel, and the dotted line circle actually indicates the phosphor image, but the G pixel indicates the phosphor image. A phosphor image not received as a body image is shown.

If the numbers of the i-th row and the j-th column are _assigned as shown in FIG. 7 in order to specify the phosphor image of each G, the horizontal arrangement pitch P _CRTX 'of the phosphor images is the same as that of the same row. Since it is defined as a distance difference between adjacent phosphor images, for example, the horizontal position X11 of the phosphor image G11 in the first column in the first row and the horizontal direction of the phosphor image G13 in the third column Is calculated as the distance from the position X13.

FIG. 8 shows an example of G pixel data constituting a G phosphor image. In the figure, the G pixel data at the hatched position constitutes the G phosphor image, and the G phosphor image has the vertical stripe pattern as described above. The horizontal position coordinates (hereinafter referred to as X coordinates) of the phosphor image are specified from the image data of the vertical stripe pattern. For example, the position of the left end column among the G pixel data strings constituting the phosphor image P _L, the position P _C of the position P _R or center column of the rightmost column may be an X-coordinate of the fluorescent body image. Alternatively, the horizontal luminance center P _D calculated from the G pixel data forming the G phosphor image may be used as the X coordinate.

[0054] Therefore, the fluorescent body image G11 and fluorescers image G13 is the pixel data of G, for example, if it is configured as shown in FIG. 9, for example, the position P _L of the left column of the fluorescent body image Taking the X coordinate, the X of the phosphor image G11
By calculating the distance L between the coordinate P _L11 and the X coordinate P _L13 of the phosphor image G13, the horizontal arrangement pitch P of the phosphor image is calculated.
_CRTX 'is calculated.

The G phosphor image is composed of discrete G pixel data, and the vertical stripe pattern formed by the G pixel data is often different for each G phosphor image. 9), the X coordinate of each G phosphor image specified by the above method does not usually accurately indicate the lateral position of the phosphor image. For this reason, if the distance between any adjacent G phosphor images in any row is calculated as the horizontal arrangement pitch P _CRTX ′ of the phosphor images, the G phosphor image of the calculation target is calculated. The error of the arrangement pitch P _CRTX 'increases depending on the selection method.

Therefore, in order to improve the calculation accuracy of the arrangement pitch P _CRTX ', it is preferable to calculate the distance L between the G phosphor images which are as far apart as possible in the horizontal direction, and calculate the distance L as the G phosphor image. Average value L divided by the number N of arrangement pitches included between images
/ N is preferably the horizontal arrangement pitch P _CRTX 'of the phosphor image.

In FIG. 7, when the phosphor image G _{ij in} the j-th column and the phosphor image G _ik in the k-th (> j) column included in the i-th row are used, the phosphor image G the X coordinate of the _ij X _ij, fluorescers image G
_{Assuming that} the X coordinate of _ik is X _ik , L = X _ik −X _ij and N = (k
−j) / 2, so that the horizontal arrangement pitch P of the phosphor image
_CRTX 'is calculated by the following _equation (8).

[0058]

P _CRTX ′ = L / N = 2 (X _ik −X _ij ) / (k−j) where i = 1, 2,..., N, j, k = 1, 3, 5,.
1, k> j FIG. 10 shows a captured measurement pattern image, which corresponds to FIG. 4B. As described above, the amount of misconvergence in the horizontal direction is measured using the image data of the vertical line measurement area 24. Therefore, the current magnification β ₀ of the imaging lens system 12 is changed to the phosphor image in the vertical line measurement area 24. Horizontal pitch P _CRTX ′
And is calculated from the above equation (7).

In this case, the horizontal arrangement pitch P _CRTX 'of the phosphor images is determined by the cross hatch pattern 20 as described above.
Of the phosphor images constituting the vertical line, the phosphor image most distant in the horizontal direction, that is, the phosphor image near both edges of the vertical line, is calculated. Since the width of the line is narrow and usually contains only about 3 to 4 phosphor images in the horizontal direction of the line, the phosphor image in the vertical line measurement area 24 is used to arrange the phosphor images with high precision. It is difficult to calculate the pitch P _CRTX '.

Therefore, an area 25 including a horizontal line of the cross hatch pattern 20 having a large number of phosphor images in the horizontal direction is defined as a phosphor image array pitch calculation area (hereinafter, referred to as array pitch calculation area). In the array pitch calculation area 25, the array pitch P _CRTX ″ in the horizontal direction of the phosphor image is calculated,
This arrangement pitch P _CRTX ″ is subjected to a predetermined correction to obtain an arrangement pitch P _CRTX ′ in the vertical line measurement area 24. The predetermined correction is the arrangement pitch calculation area 25 based on the distortion of the imaging lens system 12. Array pitch P at
_This is for correcting an error between _CRTX ″ and the arrangement pitch P _CRTX ′ in the vertical line measurement area 24.

That is, the arrangement pitch of the phosphor images in the vertical line measurement area 24 when there is no distortion of the imaging lens system 12 is P _CRTX0 ′, and the vertical line measurement area when there is distortion of the imaging lens system 12. The arrangement pitch of the phosphor images at 24 is P _CRTX ', and the arrangement pitches P _CRTX0 ' and P _CRTX 'based on the distortion of the imaging lens system 12.
_Assuming that the displacement amount is DIS _M ′ [%], the arrangement pitch P _CRTX ′ is expressed by the following _equation 9 from the displacement amount change rate DIS _M ′ and the arrangement pitch _{PC RTX0} ′.

[0062]

P _CRTX '= P _CRTX0 ' (1 + DIS _M '/ 100) On the other hand, the imaging lens system 1 in the array pitch calculation area 25
The array pitch of the phosphor images when there is no distortion 2 is P
_CRTX0 ″, the array pitch of the phosphor images P _{C RTX0} ″
Since the error between the arrangement pitch P _CRTX0 'of the phosphor image in the vertical line measurement area 24 and the arrangement pitch P _CRTX0 ' of the phosphor image is negligible, the arrangement pitch in the arrangement pitch calculation area 25 is replaced with the arrangement pitch P _CRTX0 'of the phosphor image. Using P _CRTX0 ″, the array pitch P _CRTX ′ can be calculated by the following _{equation (} 10).

[0063]

P _CRTX ′ = P _CRTX0 ″ (1 + DIS _M ′ / 100) The array pitch P _CRTX0 ″ when there is no distortion of the imaging lens system 12 in the array pitch calculation area 25 is the actual phosphor image array. The image _forming position of the two phosphor images to be calculated for calculating the pitch P _CRTX ″ is corrected to the _{image forming} position where there is no distortion of the imaging lens system 12, and the corrected image between the fluorescent image is corrected. Is calculated using the distance L0 of the above _{equation (} 8).

[0064] Specifically, in FIG. 10, the fluorescent body image G _B of G in the fluorescent body image G _A and the left end position B of G at the right end position A included in horizontal lines of the crosshatch pattern 20 _{Is used} to calculate the array pitch P _CRTX ″ of the phosphor images,
Assuming that the imaging positions of the phosphor images G _A and G _B when there is no distortion of the imaging lens system 12 are A ₀ and B ₀ , the horizontal distance between A ₀ B ₀ is the corrected fluorescence. The distance between the light body images is L ₀ . Then, the distortions at the positions corresponding to the points A and B of the imaging lens system 12 are respectively calculated as DIS _A and DIS _B [%].
When the A ₀ B ₀ between the distance L ₀ in the horizontal direction is represented by the following Equation 1
It is represented by 1.

[0065]

L ₀ = (distance L1 between OA) / (1 + DIS _A / 100)
+ (Distance between OB L2) / (1 + DIS B / 100) Here, O is an intersection of the line segment connecting the Y axis and A ₀ B ₀ of the XY coordinates set on the imaging screen 22. In FIG. 10,
The reference point of the XY coordinates is coincident with the intersection O.

[0066] Thus, fluorescers image G _A, When G _B is in the j-th column and the k (> j) th column in the same row, respectively, the arrangement pitch in the absence of distortion of the imaging lens system 12 The arrangement pitch P _CRTX0 ″ of the phosphor images in the calculation area 25 is calculated by the following _equation (12).

[0067]

P _CRTX0 ″ = 2L ₀ / (k−j) Note that the arrangement pitch P of the phosphor images in the vertical line measurement area 24 based on the distortion of the imaging lens system 12.
_CRTX0 'and P _crtX' shift amount DIS _M with 'is calculated using the distortion of the region corresponding to the vertical line measurement area 24 of the imaging lens system 12.

[0068] In FIG. 10, for example, arranged in the vertical line measurement area 24 pitch P _crtX fluorescent body image G _C of G that is the calculation target when the was calculated directly ', the position of the G _D C, as D, the fluorescent body image G _C when there is no distortion of the imaging lens system 12, when the imaging position of G _D and C _0, D _0, the deviation amount DIS _M of the arrangement pitch 'is between C ₀ D ₀ distance difference 'lateral distance L between the CD for' and C ₀ D lateral distance L ₀ between ₀ 'lateral distance L ₀ (L'-
L ₀ ') the ratio of the _{(L'-L 0') /} L 0 ' is represented by × 100 [%].

Assuming that the distortions at the positions corresponding to the points C and D of the imaging lens system 12 are DIS _C and DIS _D [%], respectively, the horizontal distance L ₀ ′ between the C ₀ D ₀ is as follows. 1
3, the above DIS _M ′ can be obtained by the following equation (14).

[0070]

L ₀ ′ = (distance L 1 ′ between O′C ₀ ) / (1 + DIS _C /
100) + (distance L2 ′ between O′D ₀ ) / (1 + DIS _D
/ 100) Here, O ′ is the intersection of the Y axis of the XY coordinates and the line connecting C ₀ D ₀ (see FIG. 10).

[0071]

[Equation 14]

Therefore, using the array pitch P _CRTX0 ″ of the phosphor image calculated by the above _equation (12) and the displacement amount DIS _M ′ of the array pitch calculated by the above _{equation (} 14), the vertical line measurement area 24 is calculated by the arrangement pitch P _crtX 'is calculated, still the arrangement pitch P _{CR TX'} imaging lens system by the number 7 and a arrangement pitch P _crtX the phosphor of the CRT 1 1
A current magnification β _{0 of} 2 is calculated.

As described above, the imaging lens system 12 is automatically set to the appropriate magnification β _R by the following procedure. Region 2 including horizontal line of cross hatch pattern 20
5 and the arrangement pitch calculation area, fluorescent body image G _A two G are as far apart as possible in the horizontal direction in this area, to extract G _B.

The imaging lens system 1 stored in the memory 8
2 of distortion characteristics and fluorescent body image G _A, the imaging position A in G _B, B
Calculates the imaging position A _0, B ₀ of the fluorescent body image G _A, G _B in the absence of distortion of the imaging lens system 12 and a further the A ₀
Lateral distance L ₀ and fluorescent body image G _A between B _0, the arrangement pitch of the fluorescent body image in the case where there is no distortion of the imaging lens system 12 and a sequence number of pitches N included between G _B P _CRTX0 ″ (= L ₀ /
N) is calculated.

In the vertical line measurement area 24, two G phosphor images G _C and G _D which are separated as much as possible in the horizontal direction
Is extracted.

The imaging lens system 1 stored in the memory 8
2 of distortion characteristics and fluorescent body image G _C, the imaging position C of G _D, D
From this, the shift amount DIS _M 'of the arrangement pitch of the phosphor images based on the distortion of the imaging lens system 12 is calculated.

The arrangement pitch P of the phosphor images calculated by
The arrangement pitch P _CRTX 'of the phosphor images in the vertical line measurement area 24 is calculated from the displacement amount DIS _M ' of the arrangement pitch of the phosphor images calculated by the _{formula CRTX0} ".

The current magnification β ₀ of the imaging lens system 12 is calculated from the phosphor image arrangement pitch P _CRTX 'and the phosphor arrangement pitch P _{CRTX of the CRT 1} calculated in step (1).

The current magnification β ₀ calculated in the above is compared with the preset appropriate magnification β _R, and the drive amount of the zoom lens group for setting the imaging lens system 12 to the appropriate magnification β _R is calculated.

The zoom motor 15 is driven based on the driving amount calculated in the step (1) to move the imaging lens system 12 to the appropriate magnification β _R
Set to.

When the imaging magnification of the imaging lens system 12 is automatically set to the appropriate magnification β _R by the above-described method, the setting error is ±
It has been confirmed that it can be suppressed to about 0.2%.

When the allowable range of the setting error is lower than ± 0.2%, the vertical line measurement area 24
When the width of the vertical line is narrow and can be approximated to the distance L '≒ 0 between the CDs, it can be approximated to DIS _M ' ≒ 0 in the above equation (9), and P _CRTX '= P _CRTX0 '. Further, a constant value of the deviation amount DIS _M 'when the change is small, the deviation amount regardless of the setting position of the vertical line measurement area 24 DIS _M' for setting the position of the vertical line measurement area 24 in the imaging screen 22 May be treated. In this case, if the shift amount DIS _M 'is calculated once, the same shift amount DIS _M ' can be used even when the imaging region 21 is changed, and the calculation process can be simplified. .

The distortion characteristic of the imaging lens system 12 is preferably an actually measured value obtained by actually measuring the distortion of the imaging lens system 12. It may be a value.

In the above embodiment, an example in which one color image data is used has been described. However, the arrangement pitch P _CRTX ″ of phosphor images may be calculated using two or three color image data. In this case, since the pixel data constituting the phosphor image is increased as compared with the case where one color image data is used,
For example, the pixel data forming the outline of the phosphor image estimated from the image data becomes clearer, the accuracy of the position coordinates of the phosphor image specified from the pixel data is improved, and the current magnification of the imaging lens system 12 is improved. The calculation accuracy of β ₀ can be further improved.

In the above embodiment, when the current magnification β ₀ of the imaging lens system 12 is different from the appropriate magnification β _R when measuring the amount of misconvergence, the zoom motor 15 is always used.
To adjust the imaging magnification of the imaging lens system 12 to the appropriate magnification β _R
However, the imaging lens system 1 is unnecessarily
Driving the second zoom lens group hinders the reduction of the measurement time and shortens the life of the imaging lens system 12, which is not preferable.

Therefore, an error between the calculated current magnification β ₀ of the imaging lens system 12 and the appropriate magnification β _R is determined by a predetermined reference range S _A.
When located within the imaging magnification of the imaging lens system 12 does not automatically set to an appropriate magnification beta again proper magnification is regarded as being set to _R beta _R, only properly again when the error exceeds a predetermined range Preferably, the magnification β _R is automatically set. For example, if β _R / β ₀ ≦ C (constant), the imaging lens system 12
Assumes that the appropriate magnification β _R has been set, and immediately proceeds to the operation of measuring the amount of misconvergence, where β _R / β ₀ > C
If so, the imaging lens system 12 is set again to the appropriate magnification β _R. Here, the criterion C is a constant determined in advance according to the required measurement accuracy.

If the error between the current magnification β ₀ of the imaging lens system 12 and the appropriate magnification β _R is relatively large, the calculation accuracy of the current magnification β ₀ calculated from the image data of the measurement pattern decreases, and It is difficult to accurately set the lens system 12 to the appropriate magnification β _R.

For example, when the current magnification β ₀ of the imaging lens system 12 is much larger than the appropriate magnification β _R , the number of phosphor images included in the imaging surface of the CCD 17 in the horizontal direction is reduced.
Since the denominator (k−j) of the above _equation 12 becomes smaller, the calculation accuracy of the arrangement pitch P _CRTX0 ″ of the phosphor images is reduced, and the calculation accuracy of the current magnification β ₀ of the imaging lens system 12 is reduced. I do.

If the current magnification β ₀ of the image pickup lens system 12 is much smaller than the appropriate magnification β _R , the area of the phosphor image formed on the image pickup surface of the CCD 17 becomes small. The resolution of the pixel is reduced, and it becomes difficult to accurately specify the horizontal position coordinates of the phosphor image from the pixel data. Therefore, the numerator L _{0 in the equation (} 12) becomes inaccurate, the calculation accuracy of the phosphor image arrangement pitch P _CRTX0 ″ is reduced, and the current magnification β of the imaging lens system 12 is reduced.
The calculation accuracy of ₀ decreases.

[0090] Therefore, when the error of the current magnification beta ₀₁ with the proper magnification beta _R of the imaging lens system 12 is first calculated as described above it is larger than a predetermined reference range S _B is the proper magnification beta _R
After driving and controlling the zoom lens group of the imaging lens system 12 to set the current magnification β ₀₂ , the current magnification β ₀₂ of the imaging lens system 12 is calculated again, and the error between the current magnification β ₀₂ and the appropriate magnification β _R is determined by the predetermined reference to determine whether the range S _a.

[0091] Then, the error between the current magnification beta ₀₂ with appropriate magnification beta _R is if within the predetermined reference range S _A, is regarded as the imaging magnification of the imaging lens system 12 is set to a proper magnification beta _R The process proceeds to the measurement of the amount of misconvergence, and the error between the current magnification β ₀₂ and the appropriate magnification β _R is determined by the predetermined reference range S _A.
If not, the zoom lens group of the imaging lens system 12 is drive-controlled based on the error between the current magnification β ₀₂ and the appropriate magnification β _R to set the appropriate magnification β _R again. Hereinafter, the error of the n-th current magnification beta _0n the proper magnification beta _R until entering the predetermined reference range S _A, is repeated a plurality of times a drive control of the zoom lens group of the imaging lens system 12.

By controlling the driving of the zoom lens group of the imaging lens system 12 as described above, the imaging lens system 1 is controlled.
Appropriate magnification β _R that satisfies the required measurement accuracy with an imaging magnification of 2
Can be automatically set quickly.

[0093]

As described above, according to the present invention, from the image signal of the captured measurement pattern image, the fluorescence in the array pitch calculation area including the light emission area larger than the light emission area of the measurement area in the horizontal direction is obtained. Calculating the arrangement pitch of the phosphor images, calculating the arrangement pitch of the phosphor images in the measurement region from the arrangement pitch of the phosphor images and the distortion aberration characteristics in the measurement region and the arrangement pitch calculation region; The current imaging magnification of the imaging lens is changed from the arrangement pitch of the phosphor image in the measurement area and the arrangement pitch of the phosphors set in advance in relation to the arrangement pitch of the pixels of the imaging means to reduce the repetition error. Since the imaging magnification is automatically set, the accuracy of the arrangement pitch of the phosphors calculated from the image data can be improved, and the arrangement pitch of the phosphor images can be used repeatedly. It is possible to improve the magnification setting accuracy of the imaging lens is automatically set to a small imaging magnification of errors.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a color CRT convergence measuring apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram of a color CRT to be measured.

FIG. 3 is a diagram illustrating an arrangement of color filters of a CCD.

4A and 4B show a measurement pattern displayed on a color CRT to be measured, wherein FIG. 4A is a diagram showing an imaging region, FIG. 4B is a diagram showing a captured image of the measurement pattern, and FIG. A diagram in which the image of the horizontal line measurement area is separated into three color images,
(D) is a diagram in which the image of the vertical line measurement area is separated into three color images.

FIG. 5 is a perspective view showing a state in which a convergence measuring device is arranged on a color CRT to be measured.

FIG. 6 is a diagram showing an example of an arrangement pattern of phosphors of a color CRT to be measured.

FIG. 7 is a diagram showing an arrangement state of phosphor images formed on an imaging surface of a CCD estimated from image data of G;

FIG. 8 is a diagram showing an example of G pixel data constituting a G phosphor image.

FIG. 9 is a diagram for explaining an array pitch calculated using two phosphor images estimated from image data.

FIG. 10 is a diagram showing a captured image of a measurement pattern.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Color cathode ray tube (CRT) 2 Drive circuit 3 Measurement pattern generator 4 Imaging device (imaging means) 5 Convergence measurement device main body 6 Image memory circuit 61 A / D conversion circuit 7 Operation control circuit 8 Memory 9 Data output device 10 Data input Apparatus 11 Display device 12 Imaging lens system 13 Focus ring 14 Aperture ring 15 Zoom motor 16 Zoom motor drive circuit 17 Solid-state imaging device (CCD) 18 Switch 20 Measurement pattern (cross hatch pattern) 21 Imaging area 22 Imaging screen 23, 24 Measurement Area 25 Array pitch calculation area 31 Face plate 311 Face plate back surface (fluorescent surface) 312 Face plate surface 32 Shadow mask 33 Electron gun mount 34 Electron gun 35 Deflection yoke 36 Electron beam

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 17/00-17/06

Claims (1)

(57) [Claims] 1. An image pickup means in which pixels are regularly arranged in a two-dimensional matrix, and an image signal is obtained by photoelectrically converting an optical image, and an image storage means for storing an image signal obtained by the image pickup means. A CRT measuring apparatus for measuring various characteristics of the CRT to be measured using an image signal of a measurement area which is a partial area of an image obtained by imaging the measurement pattern image displayed on the CRT to be measured; An imaging lens capable of changing an imaging magnification that guides the measurement pattern image to a unit, an aberration characteristic storage unit storing distortion aberration characteristics of the imaging lens, and a driving unit that drives the imaging lens to change the imaging magnification. Calculating an arrangement pitch of the phosphor images in an arrangement pitch calculation area including a light emission area larger than the light emission area of the measurement area in the horizontal direction from the image signal stored in the image storage means. First array pitch calculating means,
Calculating an arrangement pitch of the phosphor images in the measurement area from the arrangement pitch of the phosphor images calculated by the first arrangement pitch calculation means and the distortion characteristics in the measurement area and the arrangement pitch calculation area; 2, an arrangement pitch calculating means, an arrangement pitch of a phosphor image preset in relation to an arrangement pitch of pixels of the imaging means, and a phosphor in a measurement area calculated by the second arrangement pitch calculating means. A CRT measuring apparatus comprising: a magnification correcting unit that changes a current imaging magnification of an imaging lens based on an image arrangement pitch and corrects the imaging magnification with a small repeating error.