JPH02265145A - Strain measuring apparatus of image display device - Google Patents

Abstract

PURPOSE:To easily recognize generation of strain and the position of the generated strain by taking a lattice pattern image displayed on a screen of an image display to be inspected with a solid imaging device, converting an image signal, which is put out from a solid imaging device, into binary signals, and displaying a lattice pattern according to the binary signals on a monitoring device. CONSTITUTION:At the time of strain measurement, a lattice pattern is displayed on an image display to be inspected 11 and photographed by a solid imaging device 20. When a strain is produced in the image display to be inspected 11, straight lines of the lattice pattern are displayed as curved lines on the screen of the image display to be inspected. After the image signals of the curved line parts are photographed by a solid imaging device 20, the signals are converted into binary signals by a binary-forming circuit 24 and a monitor is operated according to the binary signals. By converting the output signals from the solid imaging device 20 into binary signals, curved line parts where strains are produced are displayed by mosaic-like lines, that is, dotted lines. By this method, recognition of curved parts becomes easy and strain generation can be confirmed easily.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an apparatus for measuring distortion of image displays.

[Conventional technology]

A video printer displays an input image on an image display and records it on a photosensitive material.

This image display includes CRT, flat CRT,
Liquid crystal displays and the like are used, but in order to obtain good printing performance, these image displays are required to display images without distortion.

[Problem to be solved by the invention]

For example, it is known that CRT distortions include barrel-shaped, pincushion-shaped, etc., and a test pattern generator is used to display a grid pattern during shipping inspection of a CRT uni-nod, and a ruler, etc. The distortion of the image was checked 8 times by visual inspection. And if distortion occurs,
Distortion is removed by adjusting the distortion correction circuit, and those that cannot be removed are rejected. However, this visual inspection method has the problem that it is difficult to detect the order and degree of distortion.

On the other hand, it is possible to determine the occurrence and degree of distortion by capturing the image displayed on the test CRT etc. with a TV camera and comparing it with reference data input in advance, but in this case, , a new problem arises in that a configuration for comparison with reference data is required, which complicates the device configuration.

SUMMARY OF THE INVENTION An object of the present invention is to provide a distortion measuring device for an image display, which has a simple configuration, and allows easy finding of a portion where distortion occurs.

[Means to solve the problem]

In order to achieve the above object, the present invention provides means for displaying a lattice pattern on the display surface of a test image display, and a solid-state image sensor that captures an image of the display surface of the test image display and generates an image signal. and a means for binarizing the image signal output from the solid-state image sensor to convert it into a binary signal representing whether the image signal is a line image signal of a grid pattern, and displaying the grid pattern based on the binary signal. The monitor constitutes a distortion measuring device for an image display.

Furthermore, in the image display distortion measuring device, instead of binarizing the image signal of the lattice pattern of the image display to be tested, the image signal is multi-valued, and each multi-value signal is color-coded to form the lattice pattern. Coloring is for display purposes only.

[Operation] When measuring strain, a grid pattern is displayed on the test image display, and the image is captured by a solid-state image sensor. Here, when distortion occurs in the test image display, the straight lines of the grid pattern are displayed as curved lines on the screen of the test image display. After the image signal of this curved portion is captured by a solid-state image sensor, it is converted into a binary signal by a binarization circuit, and a monitor is driven based on this binary signal. Therefore, by converting the output signal from the solid-state image sensor into a binary signal, the curved portion where distortion occurs is displayed as a mosaic of straight lines, that is, as a broken line, as shown in Figure 6. , curved portions can be easily checked, and the occurrence of distortion can be easily confirmed.

In addition, a multi-value converting circuit is installed instead of a binary converting circuit, and each multi-value signal is color-coded, and the grid pattern of the image display under test is displayed in color on a color monitor, as shown in Figure 9. It becomes easy to confirm the part where the distortion occurs, and the direction in which the distortion occurs can also be easily confirmed because the lattice pattern is displayed in different colors depending on the bend.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, the CRT unit 10 to be tested is comprised of a CRT II to be tested, a driver 12, and a test pattern generator 13 connected to the driver 12. In the pattern generator 13, emission data of a lattice pattern for one frame is written in advance, and the CRT
When testing II, a grid pattern in which horizontal lines and vertical lines are arranged at a constant pitch of 7 is displayed on the CRT II. FIG. 2 shows an example of this lattice pattern 15. The grid pattern 15 may have squares or rectangles.

The grid pattern 15 displayed on the CRTII is CC
T for black and white with built-in solid ↑ image element 20 consisting of D, etc.
The image is captured by the V camera 21. FIG. 3 shows the solid-state image sensor 2
In each pixel 22 of N, N+l, N+2 columns of 0, test C
This figure shows an example of a state in which the image of lines 18 of the lattice pattern displayed on the RTII is formed obliquely intersecting each Hifcell column. The image of this line 18 has a certain width W, and the brightness distribution between points AB in the width direction in the image of this line 18 is maximum at the center thereof, as shown in FIG. Therefore, for example N+
The image signal output from each pixel 22 between the CD points in one column becomes a gentle mountain-shaped curve as shown in the fifth FIQ, and this image signal is sent to the binarization circuit 24. The binarization circuit 24 converts the image signal into a binary signal depending on whether the image signal is larger than the darkness value set by the darkness value adjustment knob 25. The darkness value is changed by rotating the threshold value adjustment knob 25, and a value is used that facilitates the detection of the degree of curvature of the lines of the grid pattern in accordance with the distortion of the CRT II to be tested. Note that the dashed line in FIG. 5 represents the darkness value.

The binary signal converted by the binarization circuit 24 is output to a monitor 26 consisting of a black and white CRT. Since the monitor 26 displays an image based on a binary signal, it becomes a display screen 27 as shown in FIG.
The portion where no distortion occurs is displayed in a straight line. Therefore, by checking the broken line portion on the screen of the monitor 26, it is possible to easily know the occurrence of distortion and its occurrence position at a glance.

Next, the operation of this embodiment will be explained.

First, the driver 12 and the test pattern generator 1
3, the CRTII to be tested is driven, and a grid pattern is displayed on the screen of the CRTII to be tested. Next, the subject CR
The grid pattern displayed on TI 1 is imaged by the solid-state image sensor 20 of the TV camera 21. The output signal from the solid-state image sensor 20 is sent to the binarization circuit 24, where it is converted into a binary signal depending on whether it is larger than the dark value. The converted binary signal is sent to the monitor 26, and an image is displayed based on the binary signal. Therefore, if a distortion occurs in the grid pattern of the image display to be tested, the portion where the distortion occurs is displayed divided into broken lines on the display screen 27 of the monitor 26, as shown in FIG.

In addition, portions where no distortion occurs are displayed in a straight line. Therefore, by checking the broken line display area on the display screen 27, the occurrence of distortion and its occurrence position can be easily identified at a glance. In addition, if the amount of distortion is small and the broken line display part is continuous and it is not clear, turn the dark value adjustment knob 25.
By rotating and leveling up the darkness value, the dashed line display area is displayed even more coarsely, making it easier to confirm the dashed line display area.

In the above embodiment, the binarization circuit 24 is used to display the distortion occurrence portion in the form of a broken line on the monitor 2G. The image signal from the solid-state image sensor 31 of the camera 30 may be converted into a multi-value signal using the multi-value conversion circuit 32, and the distorted portion may be displayed in color on the color monitor 33 using this multi-value signal. .

In this case, for example, three comparators 35 to 37 are provided, different levels are set for each comparator 35 to 37, and the image signal is multivalued. The 3-bit code signal is then sent to a color encoder 38, where the code signal is encoded into R, G, and B signals. This R,
The G and B signals are sent to a color monitor 33, and the color of the distorted portion is displayed according to the degree of distortion. As a result, when the lines 18 of the lattice pattern are curved lines, as shown in the enlarged view of FIG. 8, the screen of the color monitor 33 can be color-coded to indicate areas where distortion occurs, as shown in FIG. Displayed in a mosaic pattern divided by straight lines.

In addition, portions without distortion are displayed as straight lines in one color. Therefore, it is possible to easily identify at a glance the parts where distortion occurs and the parts where no distortion occurs, and it becomes possible to easily see the occurrence of distortion, the location where it occurs, and the direction of bending. . In particular, by displaying the color components in multivalued form, it becomes possible to visually recognize the amount of distortion to an accuracy equal to or less than the pixel spacing of the solid-state image sensor, improving detection accuracy.

Note that by changing the reference level of the multi-level conversion circuit 32,
The display state can be changed by coloring the curved portion where distortion occurs. Therefore, by changing the bell by adjusting e and g according to the amount of strain, it becomes easy to confirm the curved portion.

Further, in this embodiment, the multi-value converting circuit 32 is composed of three comparators 35 to 37, but instead of this, two or four or more comparators can be used. Furthermore, multi-value processing can be achieved by using one comparator and changing its level.

〔Effect of the invention〕

As explained above, according to the present invention, an image of a lattice pattern displayed on the display surface of a test image display is captured by a solid-state image sensor, an image signal output from the solid-state image sensor is binarized, and the image signal is binarized. Since a grid pattern with binary coding is displayed on the monitor, if distortion occurs in the test image display, the line in this part will change into a broken line divided into short straight lines according to the bend. displayed on the monitor. Therefore, by checking the broken line portion, the occurrence of distortion and its location can be easily identified at a glance.

Further, by providing a multi-value circuit in place of the binarization circuit and displaying the curved portion in color according to the multi-value signal, it becomes easier to confirm the curved portion.

Furthermore, by displaying the color, the bending direction can be easily confirmed, and the distortion detection accuracy can be improved.

Furthermore, compared to the case where reference data that has been written in advance is used, the configuration can be simplified because such a reference data storage circuit and comparison circuit are not used.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a distortion measuring device for an image display embodying the present invention. FIG. 2 is an explanatory diagram showing an example of a lattice pattern. FIG. 3 is an explanatory diagram showing, in an enlarged manner, an example of a state in which lines of a solid-state image pickup device's mucolattice pattern are imaged. FIG. 4 is a diagram showing the luminance distribution between points AB in FIG. 3. FIG. FIG. 5 is a diagram showing output signals from each pixel between the CD points in the N+1 column in FIG. 3. FIG. 6 is an explanatory diagram showing an example of the display screen of the monitor. FIG. 7 is a schematic diagram showing the main part configuration of another embodiment. FIG. 8 is an explanatory diagram showing an enlarged part of the lines of the grid pattern displayed on the CRT to be tested in the same embodiment. FIG. 9 is an explanatory diagram showing an example of a display screen of a color monitor in the case of the lines shown in FIG. 8. Tested CRT 31...Solid-state image sensor...Vixel...Binarization circuit...Monitor...Multi-value conversion circuit...Color monitor color encoder.

Claims (2)

[Claims] (1) means for displaying a lattice pattern on the display surface of a test image display; a solid-state imaging device that captures an image of the display surface of the test image display and generates an image signal;
The image signal output from this solid-state image sensor is binarized, and 2 is used to indicate whether the image signal is a grid pattern line image signal or not.
1. A distortion measuring device for an image display, comprising means for converting into a value signal, and a monitor for displaying a grid pattern based on the binary signal. (2) means for displaying a lattice pattern on the display surface of the test image display; a solid-state image sensor that captures an image of the display surface of the test image display and generates an image signal;
A means for converting the image signal output from the solid-state image sensor into a multi-value signal indicating whether the image signal is a line image signal of a grid pattern, and a means for converting the image signal outputted from the solid-state image sensor into a multi-value signal representing whether the image signal is a line image signal of a grid pattern, and a means for color-coding each multi-value signal to generate a grid pattern. A distortion measuring device for an image display, comprising a color monitor that displays images in color.