JPH066837A - Crt measurement device - Google Patents

Abstract

PURPOSE:To set an image pickup magnification of the CRT measurement device automatically to a proper magnification with high accuracy. CONSTITUTION:A CCD 17 picks up a measurement pattern image displayed on a CRT 1 at the start of measurement and picture data are stored in a picture memory circuit 6. An arithmetic operation control circuit 7 calculates an arrangement pitch of a phosphor image in an arrangement pitch calculation region having a larger light emitting region than a prescribed measurement region in the lateral direction from the picture data and applies a prescribed correction to the distortion aberration of a pickup lens system 12 to the arrangement pitch to calculate the arrangement pitch of the phosphor image in the measurement region. Furthermore, a current pickup magnification betaO of the image pickup lens system 12 is calculated from the arrangement pitch of the phosphor image in the measurement region and a zoom motor 15 is subject to drive control through a zoom motor drive circuit 16 based on a deviation between the pickup magnification betaO and a proper magnification betaR thereby setting automatically the image pickup lens system 12 to the proper magnification betaR.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CRT measuring device for measuring various characteristics of a CRT to be measured, and more particularly to a CRT equipped with an image pickup device whose image pickup magnification is automatically set to a predetermined magnification.
The present invention 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 have been obtained by using an image signal of a measurement pattern displayed on a face plate of the color CRT. A CRT measuring device for calculating is known.

For example, in convergence adjustment,
CR for measuring the amount of color CRT misconvergence
A T measuring device is known, and Japanese Patent Application Laid-Open No. 2-174492 discloses a cross hatch measuring pattern displayed on a color CRT to be measured by setting an imaging magnification of an image pickup lens of a CRT measuring device to a predetermined magnification β _R. A method of reducing the repetition error of the convergence measurement by imaging is shown.

Here, the predetermined magnification β _R means the arrangement pitch P in the lateral direction of the fluorescent substance images on the image pickup surface of the image pickup device (hereinafter referred to as CCD) having pixels arranged regularly in a two-dimensional matrix. _CRTX 'is a magnification (hereinafter referred to as an appropriate magnification) that is an integral multiple of the CCD array pitch P _{CCDX in} the horizontal direction. For example, when the image pickup surface of the CCD is arranged parallel to the display surface (face plate surface) of the color CRT to be measured, the arrangement pitch P _{CRTX of the} fluorescent substance images formed on the image pickup surface of the CCD in the lateral direction. ′ Is the measured color CRT
P from the array pitch P _CRTX of the fluorescent bodies formed on the back surface of the face plate of P and the imaging magnification β ₀ of the imaging lens at the time of imaging
_CRTX ′ = β ₀ · P _{CRTX Therefore} , the proper magnification β _R is β
_{It is represented by R} = K · P _CCDX / P _CRTX (K; integer proportional constant).

In the above publication, for example, a measurement pattern displayed on a color CRT to be measured is imaged at the time of measurement, and the spatial frequency of the fluorescence image, that is, the fluorescence image is obtained from the image signal of the measurement pattern. Horizontal arrangement pitch P
It has been suggested that a method of automatically setting the image pickup magnification of the image pickup 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 the fluorescent object images of the same color adjacent to each other. For example, since the G fluorescent object image is composed of discrete pixel data received by the G pixels, It is difficult to pinpoint the lateral position. For this reason, there is a large error in the lateral array pitch P _CRTX ′ of the fluorescent body images detected by the fluorescent body image selected as the array pitch calculation target, and this is calculated from this array pitch P _CRTX ′. The error in the drive control amount of the photographing lens for setting the proper magnification β _R becomes large, and a precision problem occurs.

In order to solve the above problem, for example, the average value L / N obtained by dividing the distance L of two phosphor images separated by N arrangement pitch by the arrangement pitch number N is the lateral side of the phosphor image. Direction array pitch P _CRTX ′, and the array pitch P _CRTX ′
Although it is possible to reduce the calculation error of, if the measurement pattern image in the measurement area is a vertical line with a short width,
In some cases, the number of fluorescent images in the horizontal direction included in the vertical line is small, and the calculation error cannot be sufficiently reduced in accuracy.

In order to solve this problem, an area including a large number of fluorescent body images in the lateral direction is set as an array pitch calculation area, and the fluorescent object images in the array pitch calculation area are arranged in the lateral direction P _CRTX ″. It is also possible to calculate the arrangement pitch P _CRTX ″ as the arrangement pitch P _CRTX ′ in the lateral direction of the phosphor image in the measurement area, but it is possible to measure the arrangement pitch with the calculation area of the arrangement pitch _{depending on} the aberration characteristics of the imaging lens. If the array pitch of the fluorescent substance images formed in the area is different, an error occurs between the array pitch P _CRTX ″ and the array pitch P _CRTX ′, and due to this error, the proper magnification β _R of the taking lens is automatically set. The accuracy of will decrease.

The above-mentioned Japanese Patent Laid-Open No. 2-174492 discloses that
The lateral arrangement pitch P _CRTX ′ of the fluorescent body images is detected from the image signal of the imaged measurement pattern, and the imaging magnification of the imaging lens is properly adjusted using the lateral arrangement pitch P _CRTX ′ of the fluorescent body images. Although a method to automatically set the magnification β _R is shown,
No specific method is disclosed, and the above problem is not described at all.

The present invention has been made in view of the above problems, and improves the accuracy of setting the image pickup lens to an appropriate magnification,
CRT that can improve the measurement accuracy of various measured quantities
An object is to provide a measuring device.

[0011]

In order to solve the above problems, the present invention relates to an image pickup means in which pixels are regularly arranged in a two-dimensional matrix and an optical image is photoelectrically converted to obtain an image signal, and the image pickup means. 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 capturing the measurement pattern image displayed on the CRT to be measured. In a CRT measuring device for measuring various characteristics of a measurement CRT, an image pickup lens capable of changing the image pickup magnification for introducing the measurement pattern image to the image pickup means, and an aberration characteristic storage means storing distortion aberration characteristics of the image pickup lens, An array including a driving unit that drives the imaging lens to change the imaging magnification, and a light emitting region that is larger than the light emitting region of the measurement region in the horizontal direction, based on the image signal stored in the image storage unit. A first arrangement pitch calculation means for calculating a pitch of the fluorescent body image in pitch calculation area,
Calculating an array pitch of the fluorescent body images in the measurement region from the array pitch of the fluorescent body images calculated by the first array pitch calculation means and the distortion aberration characteristics in the measurement region and the array pitch calculation region; 2 array pitch calculating means, the array pitch of the phosphor image preset in relation to the array pitch of the pixels of the image capturing means, and the phosphors in the measurement region calculated by the second array pitch calculating means. Magnification correcting means for changing the current image pickup magnification of the image pickup lens from the image arrangement pitch and correcting the image pickup magnification with a small repetition error.

[0012]

According to the present invention, the image signal of the measurement pattern displayed on the CRT to be measured is stored in the image storage means. An array pitch calculation region including a light emission region larger than a light emission region of a predetermined measurement region in the lateral direction is extracted from the image signal stored in the image storage means, and the array pitch of the fluorescent body images in this array pitch calculation region is calculated. To be done. Further, the array pitch of the fluorescent body images in the measurement area is calculated from the calculated array pitch of the fluorescent body images in the array pitch calculation area and the distortion characteristic in the measurement area and the array pitch calculation area.

Then, based on the calculated array pitch of the fluorescent body images in the measurement region and the array pitch of the fluorescent body images preset in relation to the array pitch of the pixels of the image pickup means, the current image pickup lens is obtained. A correction amount for correcting the image pickup magnification of 1 to an image pickup magnification having a small repetition error is calculated, the image pickup lens is driven based on this correction amount, and the image pickup magnification of the image pickup lens is automatically set to the image pickup magnification having a small repeat error. .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram showing an embodiment of a CRT measuring device according to the present invention. The CRT measuring device shown in the figure is a schematic configuration diagram of a convergence measuring device for measuring the amount of misconvergence of a color CRT.

In the figure, 1 is a color cathode ray tube to be measured (hereinafter referred to as CRT), 2 is a drive circuit for controlling the drive of the CRT 1, and 3 is a measurement for generating a predetermined measurement pattern, for example, a crosshatch pattern. It is a pattern generator for.

The CRT 1 is, for example, a shadow mask type color cathode ray tube, and as shown in FIG. 2, a face plate 31 which mainly displays an image, a shadow mask 32, and an electron gun which generates three electron beams 36. It is composed of a mount 33. Back of face plate 31
In No. 1, phosphors of three colors R (red), G (green), and B (blue) are regularly arranged and baked to form a fluorescent surface. The three electron beams 36 emitted from the three electron guns 34 provided on the electron gun mount 33 corresponding to R, G, and B are deflected by the deflection yoke 35, and the fluorescent surface 31 is obtained.
Scan 1. Each electron beam 36 has a shadow mask 32
Only when passing through the holes of the shadow mask 32, the fluorescent surface 311 is reached and only the fluorescent bodies of the corresponding colors are caused to emit light. As a result, the face plate 3
A predetermined image is displayed at 1.

When performing the convergence measurement, the measurement pattern generator 3 generates a measurement pattern, and the 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 T1 electron gun 34, and a predetermined fluorescent body on the fluorescent surface 311 is caused to emit light to display a measurement pattern on the face plate 31.

Returning to FIG. 1, the convergence measuring device comprises an image pickup device 4 and a measuring device body 5 for calculating a misconvergence amount from an image signal picked up by the image pickup device 4.
It consists of and.

The image pickup device 4 includes a solid-state image pickup device (hereinafter referred to as CCD) 17 for picking up an image and a CRT on the CCD 17.
The image pickup lens system 12 for forming an image of the measurement pattern displayed on the display 1 is used to capture the measurement pattern image displayed on the fluorescent surface 311 of the CRT 1.

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

The image pickup device 4 includes a focus adjusting mechanism for adjusting the focus of the image pickup lens system 12, an aperture changing mechanism for adjusting the aperture value, and a zoom mechanism for adjusting the image pickup magnification of the image pickup 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 the aperture ring 14.
It is performed by rotating. The zoom mechanism includes a zoom motor 15 that is a drive source of the zoom lens group of the image pickup lens system 12 and a zoom motor drive circuit 16 that controls the drive of the zoom motor 15.
The imaging magnification of No. 2 is adjusted by a control signal from the arithmetic control circuit 7 in the measuring apparatus 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 control circuit 7.

Returning to FIG. 1, the measuring apparatus main body 5 includes an image memory circuit 6 for storing image signals picked up by the image pickup apparatus 4, an arithmetic control circuit 7 for controlling the operation of convergence measurement, and a memory for various arithmetic 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 is an A / D conversion circuit 6
1 and 3 backup memories 6a, 6b and 6c are provided, and image signals (analog signals) of R, G and B colors input from the image pickup device 4 are converted into digital images by an A / D conversion circuit 61. It is converted into a signal (hereinafter referred to as image data) and temporarily stored in each of the backup memories 6a, 6b and 6c. The memory 8 stores a calculation control program for calculating a misconvergence amount, a distortion aberration characteristic of the imaging lens system 12, and other data necessary for calculation, and the calculation result and the data input device 10 are input. Data is also stored.

The arithmetic control circuit 7 is an arithmetic circuit composed of a microprocessor, which controls the operation of the measuring device in accordance with an arithmetic control program stored in the memory 8 and also stores 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 is output to the data output device 9. The data input device 10 is for inputting various data to the arithmetic control circuit 7 from the 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 the misconvergence amount such as the 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 crosshatch pattern 20 for measurement on the entire face plate 31 of the CRT 1.
Is displayed. Reference numeral 21 denotes an imaging region for measuring the amount of misconvergence, which is a region including cross points so that the amount of misconvergence can be measured in both the vertical and horizontal directions.

Further, FIG. 4B shows an image obtained by picking up the image pickup area 21. In the figure, 22
Is an image pickup screen of the CCD 17. Further, 23 is 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 crosshatch 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 crosshatch pattern 20 (hereinafter referred to as a vertical line measurement area).

FIG. 4C shows the image data of R, G and B in the horizontal line measurement area 23, and the hatched portion is the horizontal line portion of the crosshatch pattern. In addition, r _DY , g _DY , and b _DY are R, G, and B, respectively.
Is the luminance centroid of the horizontal line of each color.

FIG. 4D shows the image data of R, G and B in the vertical line measurement area 24, and the shaded portion is the vertical line portion of the crosshatch pattern. In addition, r _DX , g _DX , and b _DX are R, G, and B, respectively.
Is the luminance centroid of the vertical line of each color. Note that FIG. 4 (c)
Since (d) shows the image data in the misconvergence state, the luminance centroids of the vertical and horizontal lines of each color of R, G, and B are displaced from each other.

The measurement of the amount of misconvergence is performed by 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 area 21 (hereinafter referred to as the display surface) and the imaging surface of the CCD 17 are parallel to each other, and no tilt angle is generated. Further, the XY orthogonal coordinates with the center of the area being the coordinate center O of the imaging area 21 are taken, and the X-axis direction is the horizontal direction and the Y-axis direction is 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. Further, the CCD 17 starts the image pickup operation, the picked-up image is displayed on the display device 11, and the misconvergence amount can be measured.

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. 4 (a)). Subsequently, while observing the captured image displayed on the display device 11, the focus ring 14 is adjusted to adjust the focus, 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 picked up by the CCD 17, and using this image signal, the current imaging magnification of the imaging lens system 12 (hereinafter, referred to as current magnification) β ₀ To calculate. Further, the calculated current magnification β ₀ and a predetermined magnification suitable for calculating the misconvergence amount (hereinafter referred to as an appropriate magnification) β _R
And these errors are calculated, and the imaging magnification of the imaging lens system 12 is set to the appropriate magnification β _R based on the calculation result.
Automatically set to. The details of the automatic setting process of the imaging magnification of the imaging lens system 12 will be described later.

Next, when the image pickup magnification of the image pickup lens system 12 is set to the proper magnification β _R , the image of the measurement pattern 20 is picked up by the CCD 17 again. This captured image signal is R,
The three colors G and B are separated and output to the image memory circuit 6, A / D converted, and then temporarily stored in the backup memories 6a, 6b and 6c, respectively. Then, the arithmetic control circuit 7 calculates the misconvergence amount using the image data of the three colors stored in the backup memories 6a, 6b, 6c. This calculation is performed as follows.

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

[0036]

[ _Formula 1] ΔD _RGX = Δd _RGX / β _R = (r _DX −g _DX ) / β _R

[0037]

[ _Expression 2] 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 by the same method as described above. To do. That is, the horizontal line measurement area 2 is calculated from the R, G, B image data stored in the backup memories 6a, 6b, 6c.
The image data of FIG. 3 (FIG. 4C) are extracted, and the luminance barycenter r _DY of the horizontal line measurement area 23 for each color is calculated.
Calculate g _DY and b _DY . For example, the R luminance center of gravity r _DY is calculated using the image data of the shaded area of the R pattern in FIG. Then, for example, the shift amount Δd _RGY (= r _DY −g _DY ) between the luminance centroids with the luminance centroid g _DY as a reference,
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 according} to the following formulas 3 and 4.

[0038]

[ _Formula 3] ΔD _RGY = Δd _RGY / β _R = (r _DY −g _DY ) / β _R

[0039]

(4) 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 also output to the data output device 9 for recording or display. The order of calculating the misconvergence amount in the horizontal and vertical directions may be any direction first. Further, the misconvergence amount in either direction may be calculated.

The above is the measurement of the amount of misconvergence for one image pickup region 21, but the measurement of the amount of misconvergence is also performed for other image pickup regions 21 by the same procedure as necessary. Further, a plurality of image pickup devices 4 are attached so as to pick up a plurality of image pickup regions 21 at the same time, image signals picked up by the respective image pickup devices 4 are input to the measuring device main body 5, and each of the image pickup regions 21 is described above. It is also possible to simultaneously calculate misconvergence amounts at a plurality of locations by processing and calculating image signals.

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

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

When the CCD 17 in which pixels are arranged in a stripe pattern as shown in FIG. 3 receives a dot-shaped image of a fluorescent body as shown in FIG. 6, for example, the same color as the emission color of the fluorescent body image is received. Since the pixels are arrayed discretely in the horizontal direction, the pixel data forming the phosphor image has a vertical stripe pattern.
Therefore, when the measurement is repeatedly performed, the horizontal measurement position of the CCD 17 shifts from the previous measurement position, and the vertical stripe pattern forming the fluorescent body image changes, and the vertical stripe pattern image data is used for calculation. A repetition error occurs in the luminance center of gravity of the fluorescent image, and as a result, the repetition error in measuring the lateral misconvergence amount increases.

The proper magnification β _R is determined by the arrangement pitch P _CRTX ′ in the lateral direction of the fluorescent image formed on the image pickup surface of the CCD 17 as shown in the following equation 5, and the arrangement pitch P _{CCDX in} the lateral direction of the pixels of the CCD 17. At a predetermined magnification so that the vertical stripe pattern constituting the fluorescent image is changed by the displacement of the measurement position of the CCD 17 described above, and the repetitive error of the luminance center of gravity of the fluorescent image is reduced. Is to reduce.

[0045]

[ _Equation 5] P _CRTX ′ = K · P _CCDX K; proportional constant (integer) Therefore, the measurement pattern 2 imaged at the proper magnification β _R
By using 0 image data, the repetitive error in the measurement of the lateral misconvergence amount is reduced.

By the way, the face plate 3 of the CRT 1
P between the lateral array pitch P _CRTX of the phosphors formed in No. 1 and the lateral array pitch P _CRTX ′ of the phosphor images.
_CRTX ′ = β _R · P _CRTX , so this P
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]

[ _Formula 6] β _R = K · P _CCDX / P _CRTX For example, the vertical arrangement pitch P _CRTY of the dot-shaped phosphors of the _CRT1 is 310 μm, and the horizontal arrangement pitch P _CRTX (=
√3 × P _CRTY ) is 537 μm, the lateral arrangement pitch P _CCDX of the pixels of the CCD 17 is 25.5 μm, and K = 22, the proper 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 of measurement, the image pickup device 4
Since the image pickup magnification of the image pickup lens system 12 does not match the proper magnification β _R , the current magnification β ₀ of the image pickup lens system 12 is calculated from the image data of the measurement pattern 20, and the current magnification β ₀ and the current magnification β ₀ 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 this calculation result, the imaging magnification of the imaging lens system 12 is automatically set to the proper magnification β _R.

The current magnification β ₀ of the image pickup lens system 12 is
CCD 1 from the image data of the measurement pattern 20
The array pitch P _CRTX ′ of the phosphor images on the imaging surface of _{No. 7} is calculated, and this array pitch P _CRTX ′ and the array pitch P of the _phosphors P
_Calculated from _CRTX and the following formula 7. This current magnification β
The calculation of ₀ is performed using the image data of one color, for example, the image data of G.

[0051]

## _EQU7 ## β ₀ = P _CRTX ′ / P _CRTX FIG. 7 is an array of phosphor images formed on the image pickup surface of the CCD 17 estimated from the image data of the G color stored in the image memory circuit 6. The state is displayed, and R, G, and
The symbol B indicates the emission color of each phosphor image. Also, the hatched circle shows the G fluorescent image received by the G pixel, and the circle shown by the dotted line actually has the fluorescent image, but the G pixel shows the fluorescent image. The fluorescent body image which is not received as a body image is shown.

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

FIG. 8 shows an example of G pixel data forming a G fluorescent object image. In the figure, the G pixel data at the hatched position constitutes a G fluorescent image, and the G fluorescent image has the vertical stripe pattern as described above. The horizontal position coordinate (hereinafter, referred to as X coordinate) of the phosphor image is specified from the image data of the vertical stripe pattern, and, for example, the position of the leftmost column of the G pixel data string forming the phosphor image. P _L , the position P _{R in the} rightmost row, or the position P _{C in the} central row can be set as the X coordinate of the phosphor image. Alternatively, the horizontal luminance centroid P _D calculated from the G pixel data forming the G fluorescent image may be used as the X coordinate.

Therefore, when the fluorescent body image G11 and the fluorescent body image G13 are constructed by the pixel data of G, for example, as shown in FIG. 9, for example, the position P _{L in the} leftmost column is the fluorescent body image. Taking the X coordinate, the X of the fluorescent body image G11
By calculating the distance L between the coordinate P _L11 and the X coordinate P _L13 of the fluorescent body image G13, the array pitch P of the fluorescent body images in the lateral direction is calculated.
_CRTX 'is calculated.

By the way, the G fluorescent object 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 fluorescent object image ( (See FIG. 9), the X coordinate of each G fluorescent object image identified by the above-described method does not usually accurately indicate the lateral position of the fluorescent object image. For this reason, if the distance between the adjacent G phosphor images in any row is calculated as the lateral arrangement pitch P _CRTX ′ of the G phosphor images, the G phosphor images to be calculated are calculated. The error of the array pitch P _CRTX ′ becomes large depending on the selection method.

Therefore, in order to improve the calculation accuracy of the array pitch P _CRTX ′, it is preferable to calculate the distance L between the G fluorescent object images which are separated as much as possible in the lateral direction, and to set the distance L to the G fluorescent object. Average value L divided by the number N of array pitches included between images
It is better to _let / N be the lateral array pitch P _CRTX ′ of the phosphor images.

In FIG. 7, when the phosphor image G _{ij on} the j-th column and the phosphor image G _ik on the k (> j) -th column included in the i-th row are used, the phosphor image G the X coordinate of the _ij X _ij, fluorescers image G
_If the X coordinate of _ik is X _ik , L = X _ik −X _ij , N = (k
-J) / 2, the arrangement pitch P in the lateral direction of the fluorescent 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 ... 2m +
1, k> j FIG. 10 shows the imaged measurement pattern image, which corresponds to FIG. 4B. Since the amount of misconvergence in the horizontal direction is measured using the image data of the vertical line measurement area 24 as described above, the current magnification β ₀ of the imaging lens system 12 is the fluorescence image in the vertical line measurement area 24. Horizontal arrangement pitch P _CRTX ′
It will be calculated from the above Equation 7 using

In this case, the array pitch P _CRTX ′ in the lateral direction of the fluorescent image is the cross hatch pattern 20 as described above.
Of the phosphor images that make up the vertical line, the phosphor images that are most distant in the horizontal direction, that is, the phosphor images in the vicinity of both edge portions of the vertical line will be calculated. Since the width of the line is narrow and usually only about 3 to 4 phosphor images are included in the horizontal direction of the line, the phosphor images in the vertical line measurement area 24 are used to arrange the phosphor images with high accuracy. It is difficult to calculate the pitch P _CRTX ′.

Therefore, the region 25 including the horizontal lines of the crosshatch pattern 20 having a large number of fluorescent substance images in the lateral direction is set as the calculation region of the arrangement pitch of the fluorescent substance images (hereinafter referred to as the arrangement pitch calculation region). In the array pitch calculation area 25, the array pitch P _CRTX ″ in the lateral direction of the phosphor image is calculated,
This array pitch P _CRTX ″ is subjected to a predetermined correction to obtain an array pitch P _CRTX ′ in the vertical line measurement area 24. The predetermined correction is the array pitch calculation region 25 based on the distortion of the imaging lens system 12. Array pitch P in
_{The error} between _CRTX ″ and the arrangement pitch P _CRTX ′ in the vertical line measurement area 24 is corrected.

That is, the array pitch of the fluorescent body 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 array pitch of the fluorescent image in 24 is P _CRTX ′, and the array pitches P _CRTX0 ′ and P _CRTX ′ based on the distortion of the imaging lens system 12 are _set .
When the deviation amount from the deviation amount is DIS _M ′ [%], the arrangement pitch P _CRTX ′ is expressed by the following _equation 9 from the change rate DIS _M ′ of the deviation amount and the arrangement pitch P _CRTX0 ′.

[0062]

On the other hand, P _CRTX ′ = P _CRTX0 ′ (1 + DIS _M ′ / 100) Meanwhile, the imaging lens system 1 in the array pitch calculation region 25
The array pitch of the fluorescent body images when there is no distortion of 2 is P
_CRTX0 ″, the array pitch of this phosphor image P _{C RTX0} ″
And the array pitch P _CRTX0 ′ of the fluorescent body images in the vertical line measurement area 24 is so small that it can be ignored. Therefore, instead of the array pitch P _CRTX0 ′ of the fluorescent body images, the array pitch in the array pitch calculation region 25 is set. The array pitch P _CRTX ′ can be calculated by the following _equation 10 using P _CRTX0 ″.

[0063]

Equation 10] _{P CRTX '= P CRTX0 "(} 1 + DIS M' / 100) sequence when there is no distortion of the imaging lens system 12 in the arrangement pitch calculation area 25 Pitch P _CRTX0" the actual sequence of the fluorescent body image The image _forming positions of the two fluorescent object images to be calculated for calculating the pitch P _CRTX ″ are corrected to the _{image forming} positions in the case where there is no distortion aberration of the imaging lens system 12, and between the corrected fluorescent object images. Is calculated by using the distance L ₀ of

[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 When calculating the array pitch P _CRTX ″ of the phosphor images using
Letting A ₀ and B ₀ be the image forming positions of the fluorescent body images G _A and G _B when there is no distortion of the imaging lens system 12, the lateral distance between A _{0 and} B ₀ is the corrected distance. It becomes the distance L ₀ between the light body images. Then, the distortion aberrations at the positions corresponding to the points A and B of the imaging lens system 12 are DIS _A and DIS _B [%], respectively.
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 L2 between OBs) / (1 + DIS _B / 100) Here, O is the intersection of the line segment connecting the Y axis of the XY coordinates set on the imaging screen 22 and A ₀ B ₀ . In addition, in FIG.
The reference point of the XY coordinates and the intersection point O are in the same state.

Therefore, assuming that the fluorescent substance images G _A and G _B are at the j-th column and the k-th (> j) -th column of the same row, respectively, the array pitch when there is no distortion of the imaging lens system 12 The array pitch P _CRTX0 ″ of the fluorescent substance images in the calculation area 25 is calculated by the following formula 12.

[0067]

[ _Equation 12] P _CRTX0 ″ = 2L ₀ / (k−j) It should be _noted 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
The displacement amount DIS _M ′ between _CRTX0 ′ and P _CRTX ′ is calculated using the distortion aberration of the area corresponding to the vertical line measurement area 24 of the imaging lens system 12.

For example, in FIG. 10, when the array pitch P _CRTX ′ in the vertical line measurement area 24 is directly calculated, the positions of the G phosphor images G _C and G _D to be calculated are C and D, _Assuming that the imaging positions of the fluorescent body images G _C and G _{D in} the case where there is no distortion of the imaging lens system 12 are C ₀ and D ₀ , the array pitch deviation amount DIS _M ′ is between C ₀ D ₀ . The distance difference (L′− between the lateral distance L ′ between the CDs and the lateral distance L ₀ ′ between C ₀ D ₀ and the lateral distance L ₀ ′.
It is represented by the ratio of L ₀ ′) (L′−L ₀ ′) / L ₀ ′ × 100 [%].

Assuming that the distortion aberrations at the positions corresponding to the points C and D of the image pickup lens system 12 are DIS _C and DIS _D [%], respectively, the lateral distance L ₀ ′ between C ₀ D ₀ is as follows. 1
Since it is represented by 3, the DIS _M ′ is calculated by the following formula 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) where O ′ is the intersection of the line segment connecting the Y axis of the XY coordinates and C ₀ D ₀ (see FIG. 10).

[0071]

[Equation 14]

Therefore, using the array pitch P _CRTX0 ″ of the fluorescent body images calculated by the above _equation 12 and the array pitch deviation amount DIS _M ′ calculated by the above _equation 14, the vertical line measurement area 24 is calculated by the above _equation 10. 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.

From the above, the image pickup lens system 12 is automatically set to the proper magnification β _R in the following procedure. Area 2 including the horizontal lines of the crosshatch pattern 20
5 is an array pitch calculation area, and two G fluorescent object images G _A and G _B which are laterally separated as much as possible in this area are extracted.

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, the two G fluorescent object images G _C and G _D which are separated as much as possible in the horizontal direction.
To extract.

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
Then, the displacement amount DIS _M ′ of the array pitch of the fluorescent body images based on the distortion of the imaging lens system 12 is calculated.

The array pitch P of the fluorescent body images calculated in
The array pitch P _CRTX ′ of the phosphor images in the vertical line measurement area 24 is calculated from the displacement amount DIS _M ′ of the array pitch of the phosphor images calculated by _CRTX0 ″.

The present magnification β ₀ of the image pickup lens system 12 is calculated from the array pitch P _CRTX ′ of the phosphor images calculated in step P and the array pitch P _CRTX of the phosphors of the _{CRT 1} .

The current magnification β ₀ calculated in step ₃ is compared with the preset proper magnification β _R, and the drive amount of the zoom lens group for setting the imaging lens system 12 to the proper magnification β _R is calculated.

The zoom motor 15 is driven on the basis of the drive amount calculated in to move the imaging lens system 12 to the proper magnification β _R.
Set to.

When the image pickup magnification of the image pickup lens system 12 is automatically set to the proper magnification β _R by the above 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 measuring area 24 is
When the width of the vertical line at is narrow and can be approximated to the distance L' _≈0 between CDs, it can be approximated to DIS _M ′ _≈0 in the above equation 9, and P _CRTX ′ = P _CRTX0 ′. Further, when the change in the deviation amount DIS _M ′ with respect to the setting position of the vertical line measurement area 24 in the image pickup screen 22 is small, the deviation amount DIS _M ′ is set to a constant value regardless of the setting position of the vertical line measurement area 24. You may handle it. 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 arithmetic processing can be simplified. .

The distortion aberration characteristic of the image pickup lens system 12 is preferably the actual measurement value obtained by actually measuring the distortion aberration of the image pickup lens system 12, but the design of the distortion aberration of the lenses constituting the image pickup lens system 12 is preferable. It may be a value.

Further, in the above-mentioned embodiment, the example in which the image data of one color is used has been described, but the array pitch P _CRTX ″ of the fluorescent body images may be calculated using the image data of two colors or three colors. In this case, since the pixel data forming the fluorescent image increases compared to the case of using the image data of one color,
For example, the pixel data forming the outline portion of the fluorescent body image estimated from the image data becomes clearer, the accuracy of the position coordinates of the fluorescent body image specified from the pixel data improves, and the current magnification of the imaging lens system 12 increases. It is possible to further improve the calculation accuracy of β ₀ .

By the way, in the above embodiment, when the current magnification β ₀ of the image pickup lens system 12 is different from the proper magnification β _R when measuring the amount of misconvergence, the zoom motor 15 is always used.
Drive the image pickup magnification of the image pickup lens system 12 to an appropriate magnification β _R
I was trying to correct it, but unnecessarily the imaging lens system 1
Driving the second zoom lens group is unfavorable because it hinders shortening of measurement time and shortens the life of the imaging lens system 12.

Therefore, the error between the calculated current magnification β ₀ of the image pickup lens system 12 and the proper magnification β _R is 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 It is recommended to automatically set the magnification β _R. For example, if β _R / β ₀ ≦ C (constant), the imaging lens system 12
Is regarded as being set to an appropriate magnification β _R , and immediately shifts to the measurement operation of the misconvergence amount, and β _R / β ₀ > C
If so, the imaging lens system 12 is set again to the proper magnification β _R. Here, the discrimination criterion C is a constant determined in advance according to the required measurement accuracy.

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

For example, when the current magnification β ₀ of the image pickup lens system 12 is much larger than the proper magnification β _R , the number of fluorescent body images included in the image pickup surface of the CCD 17 in the lateral direction is small,
As the denominator (k−j) of the above _equation 12 becomes smaller, the calculation accuracy of the array pitch P _CRTX0 ″ of the phosphor images decreases, which in turn decreases the calculation accuracy of the current magnification β ₀ of the imaging lens system 12. To do.

When the current magnification β ₀ of the image pickup lens system 12 is much smaller than the proper magnification β _R , the area of the fluorescent image formed on the image pickup surface of the CCD 17 becomes small, so that the CCD 17 is relatively moved. , The resolution of the pixel decreases, and it becomes difficult to accurately specify the lateral position coordinates of the fluorescent body image from the pixel data. For this reason, the numerator L ₀ of the above formula 12 becomes inaccurate, the calculation accuracy of the array pitch P _CRTX0 ″ of the phosphor image is lowered, and the current magnification β of the imaging lens system 12 is extended.
The calculation accuracy of ₀ decreases.

Therefore, when the error between the current magnification β ₀₁ of the image pickup lens system 12 initially calculated as described above and the proper magnification β _R is larger than the predetermined reference range S _B or more, the proper magnification β _R
After controlling the zoom lens group of the image pickup lens system 12 to be set to, the current magnification β ₀₂ of the image pickup lens system 12 is calculated again, and the error between the current magnification β ₀₂ and the proper magnification β _R is the above-mentioned predetermined reference. It is determined whether or not it is within the range S _A.

If the error between the current magnification β ₀₂ and the proper magnification β _R is within the predetermined reference range S _A , it is considered that the image pickup magnification of the image pickup lens system 12 is set to the proper magnification β _R. The measurement shifts to the amount of misconvergence, and the error between the current magnification β ₀₂ and the proper magnification β _R is the predetermined reference range S _A.
If it is not within the range, the drive of the zoom lens group of the imaging lens system 12 is controlled based on the error between the current magnification β ₀₂ and the proper magnification β _{R in} order to set the proper magnification β _R again. Hereinafter, the drive control of the zoom lens group of the imaging lens system 12 is repeated a plurality of times until the error between the n-th current magnification β _0n and the proper magnification β _R falls within the predetermined reference range S _A.

By controlling the drive of the zoom lens group of the image pickup lens system 12 as described above, the image pickup lens system 1
Proper magnification β _R that satisfies the required measurement accuracy with the imaging magnification of 2
Can be automatically set quickly.

[0093]

As described above, according to the present invention, the image signal of the captured pattern image for measurement is used in the arrangement pitch calculation region including the light emission region larger than the light emission region of the measurement region in the lateral direction. The array pitch of the optical image is calculated, the array pitch of the fluorescent image and the measurement region and the distortion aberration characteristics in the array pitch calculation region to calculate the array pitch of the fluorescent image in the measurement region, The current image pickup magnification of the image pickup lens is changed from the arrangement pitch of the fluorescent body images in this measurement region and the arrangement pitch of the fluorescent bodies which is set in advance in relation to the arrangement pitch of the pixels of the image pickup means to reduce the repetition error. Since the imaging magnification is automatically set, it is possible to improve the accuracy of the array pitch of the phosphor increase calculated from the image data, and repeat using this array pitch of the phosphor image. 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 drawings]

FIG. 1 is a block 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 showing an array of color filters of a CCD.

4A and 4B show measurement patterns displayed on a measured color CRT, where FIG. 4A is a diagram showing an imaging region, FIG. 4B is a diagram showing images of the captured measurement patterns, and FIG. The figure which separated the image of the horizontal line measurement area 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 with respect to a measured color CRT.

FIG. 6 is a diagram showing an example of an array pattern of fluorescent substances of a color CRT to be measured.

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

FIG. 8 is a diagram showing an example of G pixel data forming a G fluorescent object image.

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Color cathode ray tube (CRT) 2 Driving circuit 3 Measurement pattern generator 4 Imaging device (imaging means) 5 Convergence measuring device body 6 Image memory circuit 61 A / D conversion circuit 7 Arithmetic control circuit 8 Memory 9 Data output device 10 Data input Device 11 Display device 12 Imaging lens system 13 Focus ring 14 Aperture ring 15 Zoom motor 16 Zoom motor drive circuit 17 Solid-state image sensor (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

Claims (1)

[Claims] 1. An image pickup means in which pixels are regularly arranged in a two-dimensional matrix, and an optical image is photoelectrically converted to obtain an image signal, and an image storage means for storing the image signal obtained by the image pickup means. In the CRT measuring device, which is provided with the CRT measuring device and measures various characteristics of the CRT to be measured using an image signal of a measurement region which is a partial region of an image obtained by capturing the measurement pattern image displayed on the CRT to be measured, An image pickup lens capable of changing the image pickup magnification that guides the measurement pattern image to the means, an aberration characteristic storage unit that stores the distortion aberration characteristic of the image pickup lens, and a driving unit that drives the image pickup lens to change the image pickup magnification. Calculating the array pitch of the fluorescent body images in the array pitch calculation area including a light emitting area larger than the light emitting area of the measurement area in the lateral direction from the image signal stored in the image storage means. A first array pitch calculating means,
Calculating an array pitch of the fluorescent body images in the measurement region from the array pitch of the fluorescent body images calculated by the first array pitch calculation means and the distortion aberration characteristics in the measurement region and the array pitch calculation region; 2 array pitch calculating means, the array pitch of the phosphor image preset in relation to the array pitch of the pixels of the image capturing means, and the phosphors in the measurement region calculated by the second array pitch calculating means. A CRT measuring device comprising: a magnification correcting unit that changes the current imaging magnification of an imaging lens based on the image arrangement pitch and corrects the imaging magnification with a small repetition error.