JPH0630448A - Image position measuring device - Google Patents

Abstract

(57) [Summary] [Purpose] When measuring and adjusting the image distortion of the device under test,
The relative displacement between the imaging means and the image device under measurement is calibrated. [Structure] An all-white screen is projected on a screen 5 of a television receiver 4, and a picture is taken by a TV camera 7 including the edges of the effective screen, and image data is stored in an image memory 10. The image distortion based on the relative position error between the television receiver 4 and the television camera 7 is measured on the image memory 10, and the correction data for correcting the position error is stored in the correction data memory means 17. Then, the barycentric position of the image is calibrated with this correction data on the actual measurement screen, and the image distortion and convergence correction amounts are measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image position measuring device suitable for measuring distortion or convergence of an image projected on an image device, particularly a television receiver, and more particularly, it relates to an image position measuring device. It is intended to provide a calibration means for increasing the accuracy when automatically measuring.

[0002]

2. Description of the Related Art Conventionally, a television receiver using a color cathode ray tube, which has been most popularly used as an image device, has a static and It is an indispensable requirement to perform dynamic image distortion correction and misconvergence correction.

In recent years, such convergence correction has been
An imaging device, such as a TV camera, is installed at a position that opposes the tube surface of the TV receiver on the measured side, and the specific pattern projected by this TV camera is loaded into the image memory and the pattern projected is specified. Calculate the barycentric position of the electron beam irradiating the position,
An image position measuring device has been developed which measures misconvergence, image distortion and the like by examining whether or not the position matches a predetermined pattern position.

The image position measuring device shown in FIG.
The applicant of the present invention has previously proposed it as Japanese Patent Laid-Open No. 1-204594, in which a television receiver 4 serving as a device to be measured has a video circuit 3 for supplying a video signal to a CRT 1, a deflection yoke 2 and a CRT 1. It is provided. 7 is a CRT
A photographing device for photographing the tube surface 5 of 1, such as a television camera is shown, and an optical lens 6 is provided on the front side, and a photographing element 8 made of CCD or MOS or the like into which photographing light is incident is provided.

The video output signal of the photographing device 7 is taken into the image memory 10 through the analog-digital converter 9. Reference numeral 11 reads out the video data taken in the image memory 10 for each pixel by the address data from the timing signal generating circuit 16, calculates the sum of the address data in a predetermined range and the sum of the product of the brightness levels, and calculates the center of gravity of the electron beam. This is an arithmetic circuit that determines the position, and the output data of this arithmetic circuit 11 is sequentially stored in the memory 12.
The pattern signal generation circuit 15 supplies a lattice-shaped crosshatch pattern signal to the above-mentioned television receiver 1 as shown in FIG. 7, for example.

The arithmetic unit 11, the memory 12, the pattern signal generation circuit 15, and the timing signal generation circuit 16 are controlled by the control data output from the microprocessor 13, and are located on the memory at the cross points of the cross hatch pattern. The data is detected, and the measurement result is sent to the monitor 14 so that the state of image distortion and convergence can be displayed by graphic and character data. Each cross point P ₁₁ , P ₁₂ , P ₁₃ , ... of the crosshatch pattern captured in the image memory.
The position of P _{n, m} is, for example, as shown in the enlarged view of FIG. 8, a horizontal measurement area (horizontal measurement area HS) and a vertical measurement area (vertical measurement area) around the cross point P _{n, m.} Area VS) is set, the data (luminance level) of each cell in each measurement area is detected, the center of gravity is calculated by calculating the center of gravity, and the position of the cell that is the center of gravity (indicated by diagonal lines) is obtained. Data) is determined horizontally and vertically.

[0007]

In the image position measuring device as described above, the display tube surface 5 of the television receiver 4 and the image pickup surface of the image pickup element 8 of the image pickup device 7 form a parallel plane, and If the scanning line of the CRT 1 and the pixel row in the horizontal direction of the image sensor 8 are arranged in parallel, the tube surface 5
The image distortion can be detected by calculating and detecting the center of gravity of the cross points of, for example, the cross hatch pattern shown in FIG. Also,
The above crosshatch pattern is divided into 3 for each R, G, B video signal.
It is possible to detect the correction amount required for color convergence by taking the image data into each image memory and measuring the positional deviation of the cross points of the cross hatch pattern that gives the maximum brightness of each R, G, B signal.

However, when one or both of the tube surface 5 of the CRT 1 and the image pickup surface of the image pickup device 7 are inclined, the image captured by the image pickup device 7 is a cross hatch pattern projected on the CRT 1. Therefore, it is necessary to accurately set the relative positions of the television receiver 4 and the photographing device 7 in advance before the measurement.

However, such an image position measuring device is arranged on the production line of the factory, and the image position is measured by facing the CRT 1 transferred by a belt conveyor or the like, and image distortion or convergence is detected based on the measured data. When the adjustment is performed, the measurement position of the CRT 1 does not always stop at a predetermined position, and there is a problem that setting the measurement position accurately for each CRT 1 and adjusting the CRT 1 results in extremely low work efficiency. In addition, the photographing device 7
If the installation state of the CRT is wrong, especially if the TV camera is tilted, then the CRT1
The image position of will be adjusted.

[0010]

In order to solve such a problem, the present invention is directed to the above-mentioned CRT 1 in which the mutual position of the CRT 1 and the photographing device 7, particularly the inclination, rotation, etc., in the pre-measurement stage. In advance on the image memory,
A memory means for calculating and storing correction data for performing the correction is provided, and at the image position measuring stage, the correction data is used to correct the calculation data including the positional deviation between the CRT 1 and the photographing device 7. It is the one.

[0011]

Operation Even when one or both of the CRT 1 and the photographing device 7 are tilted and the parallelism between the display surface and the imaging surface is lost, the photographing device 7
By arranging the image pickup screen of (1) so as to completely capture at least the edge of the effective screen of the display surface, it becomes possible to perform calibration before measuring the image position, and more accurate position data can be obtained.

[0012]

FIG. 1 is a block diagram of an image position measuring apparatus showing an embodiment of the present invention, in which the same parts as those shown in FIG. 6 are designated by the same reference numerals. That is, the cross hatch pattern projected on the tube surface 5 of the television receiver 4 is photographed by the photographing device 7, and the image memory 1
It is taken into 0. By the way, in the image position measuring device of the present invention, when measuring the image output position of the CRT 1, first, the image photographed by the photographing device 7 is at least the CRT.
It is arranged so as to include the edge (boundary line with the bezel) of the first tube surface. That is, the image pickup device (CC
As shown in FIG. 2, all the edges of the effective screen of the television receiver are included in D), and this screen is stored in the image memory 10 as an all-white screen. Next, the outermost measurement points of the effective screen (in this embodiment, 5 points in both the horizontal and vertical directions) are arranged 5% inside, and the range of the internal measurement points is assigned. This allocation is, for example, the measurement points (a to e, a to e) between the edges with the center as the center.
The positions of ", f to j, f to j" are -0.45, -0.255, 0, +0.225, +0.45 in the horizontal and vertical directions, respectively. (Hereinafter, indicated by position coefficients K _P [H] and K _P [V].) That is, assuming that the center of the horizontal and vertical axes is 0, the positions of ± 0.225 and ± 0.45 in the horizontal and vertical directions. A measurement point is created at.

By the way, this measurement point is as shown in FIG. 3 when the screen of the television receiver imaged by the television camera 7 is distorted, for example, when the image pickup surface of the camera and the tube surface of the TV are not parallel. When a rectangular tube surface is trapezoidal and the central axis of the tube surface is rotating with respect to the center of the image pickup tube, the screen becomes an inclined screen as shown in FIG. Therefore, even if the television receiver 4 projects an accurate hatch pattern, the position data on the image memory does not output an accurate hatch pattern. Therefore, the present invention is
How much each measurement point deviates from the ideal value in the horizontal direction and in the vertical direction is calculated in advance for each device under test, and the data indicating the correction amount together with the position coefficient is calculated.
This correction data is stored in the correction data storage means 17. Then, after correcting the relative positional deviation between the television receiver and the television camera on the basis of the fetched data, the image distortion and the convergence are measured.

An example of creating correction data for performing such correction will be described below. On the X axis (c-c ') set at the center position in FIG. 2 and the Y axis (h
The data Hcent and Vcent of the center position on -h ') are calculated by the following formula. Hcent = (c-c ') / 2 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ (1-1 , Horizontal deviation from ideal value of each measurement point GHP
[V] [H] is calculated by the following formula. GHP [V] [H] = edge length [V] × K _P [H] + center between edges [V] ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ (2-1) The coefficient is the above K _P Use [h]. Of this deviation, Y
The misalignment on the axis is represented by YGMC [V]. YGMC [V] = GHP [V] [Y
Axis]. Similarly, a vertical deviation GVP [V] [H] from the ideal value of each measurement point is obtained. GVP [V] [H] = the edge length _{[H] × K P [V} ] + center between the edges [H] ‥‥‥‥‥‥‥‥‥‥ (2-1) of this deviation, X The deviation on the axis is represented by XGMC [H]. XGM
C [H] = GVP [V] [X axis].

Next, the ratio of the extension axis length of each measurement point to the X axis length is obtained as a tilt correction coefficient Xh [V].
Xh [V] = each edge length / X-axis edge length ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ (3-1) For example, the inclination correction coefficient X _h [2] at each measurement point on the line bb '
The _{X h [2] = (b} -b') / (c-c') further obtains the vertical extension coefficients tilt the axial length ratio of Yh [H] of each measurement point with respect to the Y-axis length. Yh [H] = the edge length / Y-axis edge length ‥‥‥‥‥‥‥‥ (3-2) For example, for the measuring points of g-g _{'line, Y h [2] = (} g- g ') / (h-h')

As described above, by calculating the data of each measurement point on the image memory and inputting it to the correction data storage means 17, each measurement point on the image memory generated when the hatch pattern is actually reproduced. Correct position can be corrected. For example, a grid-shaped hatch pattern displayed on a TV camera is measured, horizontal position data h _ms [V] [H] of the cross point, and vertical position V _ms [V] [H] of each position data. ] (This position data is measured in the description of FIGS. 7 and 8 described above) is corrected to accurate position data h _o [V] [H], V _o [V] [H] by the following equation. It _{h o [V] [H]} = (h ms [V] [H] -YGMC [V]) / Xh [V] ‥‥‥‥‥ (4-1) V o [V] [H] = (V _ms [V] [H] -XGMC [H]) / Yh [H] ‥‥‥‥‥‥‥‥‥ (4-2) Therefore, the measurement hatch pattern does not rotate.
In the case of, the horizontal measurement point h _ms [V] [H] (camera output image when the CRT is slightly tilted in the vertical direction) is YGMC.
Since both [V] and XGMC [H] are 0, h _o [V] [H] = h _ms [V] [H] / Xh [V] V _o [V] [H] = V _ms [V] [H] / Yh [H]

Further, when the measured image is only slightly rotated and the parallelism of both image planes is maintained (FIG. 3), Xh [V] = 1, Yh [H]. = 1, and in _{h o [V] [H]} = h ms [V] [H] -YGMC [V] V o [V] [H] = V ms [V] [H] -XGMC [H] Will be corrected.

As shown in FIG. 5, when the effective screen edge of the CRT of the television receiver to be measured is rounded and not rectangular, the correction of the radius of curvature of the long side and the short side is performed. -It is necessary to include it in the condition of the option. In the case of an image device having such a CRT, the X-axis length, the Y-axis length of the display surface of the CRT, the bending radius in the vertical edge direction, and the bending radius in the horizontal edge direction are input in advance to the calculation unit of the image position measuring device. First, the effective edge length on the extension axis of each measurement point is obtained. And the X axis and Y
The ratios to the axes are stored as contour correction coefficients K _r [V] and K _r [H]. (K _r = 1 for straight lines)

Next, the inclination correction coefficient described above is corrected by the contour correction coefficient. New slope correction coefficient X'h
[V], Y'h [H] becomes X'h [V] = Xh [V ] / K r [V] Y'h [H] = Yh [H] / K r [H].

[0020]

As described above, the image position measuring apparatus of the present invention adjusts image distortion and misconvergence by arranging a photographing camera facing an image device under measurement and by capturing a predetermined pattern in an image memory. By arranging in advance so as to include the edge portion of the effective screen of the image device under measurement, it is possible to eliminate the influence of the measurement position and obtain accurate correction data. Further, since the relative positional relationship between the image device to be measured and the measuring device is not limited, there is an advantage that it can be easily arranged in an actual manufacturing plant and highly accurate measurement can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of an image position measuring device of the present invention.

FIG. 2 is a diagram showing measurement points of an image projected on a measuring television camera.

FIG. 3 is a measurement screen when the display surface of the image-under-test device is tilted backward.

FIG. 4 is a measurement screen when the image device to be measured and the television camera are rotating relative to each other.

FIG. 5 is a measurement screen when the long side (short side) of the display surface of the image to be measured is not a straight line.

FIG. 6 is a block diagram showing a prior art of an image position measuring device.

FIG. 7 is a diagram showing measurement positions by a cross hatch pattern.

FIG. 8 is an explanatory diagram for detecting a cross point position of a cross hatch pattern.

[Explanation of symbols]

 4 television receiver 7 photographing device 10 image memory 17 correction data storage means

Claims (4)

[Claims] 1. An image pickup device which is arranged so as to face the image device under test and at least completely captures a display surface of the image device under test; and an image which takes in a video signal output from the image pickup device as image data. A memory, a pattern generator that generates a predetermined video pattern signal to be supplied to the image device under measurement, and an image data stored in the image memory,
In an image position measuring device comprising a calculation means for calculating the image position of the video pattern and a timing control means, the contour edge position of the effective screen area of the image device under test is stored on the image memory before measuring the image position. Correction memory means for storing the amount of deviation from a standard video pattern as correction data, and the correction data stored in the correction memory means allows the relative position between the image-measuring device to be measured and the photographing means. An image position measuring device characterized in that an image position is measured after correcting image distortion based on the image. 2. The correction data is image distortion data generated when the display surface of the image-under-measurement device and the photographing surface of the photographing means are not in a parallel state.
The image position measuring device according to. 3. The correction data is image distortion data generated when the image-under-measurement device and the photographing means are tilted with respect to each other in vertical planes on opposite axes.
The image position measuring device according to. 4. The correction data is converted by the correction data corrected by the data input in advance when the outermost peripheral edge of the display tube surface of the image device under measurement is deviated from the straight line. The image position measuring device according to claim 1, wherein the image position measuring device is configured as described above.