JPH059995B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention is directed to the treatment of multiple types of image quality such as poor convergence, insufficient amplitude, tilt, deviation, non-linearity, and brightness abnormalities of displayed images of CRT (cathode ray tube) display devices. Anomalies can now be automatically checked using the same test pattern.
This invention relates to an inspection device for CRT display images.

(b) Background of the technology CRT display devices raster scan an electron beam modulated by image information such as characters to be displayed.
Images such as characters are displayed on a CRT display screen, and various correction devices or adjustment devices are installed so that a clear, distortion-free image is displayed across the entire display surface.

However, due to incomplete correction or adjustment by these devices, or failure of these devices, the clarity of the displayed image may decrease due to poor convergence of the electron beam, or the electron beam may change in the main scanning direction or sub-scanning direction. Reduced or biased displayed image due to insufficient amplitude, tilted displayed image due to poor CRT installation,
Various image quality abnormalities may occur, such as distortion of the displayed image due to the nonlinearity of the electron beam deflection circuit, and brightness abnormalities due to reflection or folding at the end of the scanning line. We are conducting a thorough inspection.

(c) Problems with the Prior Art Initially, CRT display images were inspected visually, but later inspection devices came to be used to automate or quantify the inspection.

However, conventional inspection apparatuses use dedicated test patterns for each of the various inspection items as described above, resulting in the inconvenience of having to select a test pattern for each inspection item.

(d) Purpose of the Invention The purpose of the present invention is to improve inspection efficiency by using the same test pattern for multiple types of inspection items.

(e) Structure of the invention The inspection device for a CRT display device according to the present invention comprises:
In the display image inspection of a CRT display device, a non-linearity inspection pattern consisting of multiple straight lines displayed at equal intervals on the top and bottom, left and right sides of the CRT screen, and Straight line patterns for strain testing displayed on the top and bottom and left and right, and lines that are in contact with the straight line patterns for strain testing displayed on the left and right of the outermost edge on the CRT screen, and of said straight line patterns for strain testing.
A planar brightness abnormality inspection pattern displayed inward toward the center of the CRT, vertical stripes and planes displayed in the center of the CRT screen, and the outermost pattern of the CRT screen.
Displayed on at least one of both ends of the straight line pattern for strain testing displayed on the upper and lower parts of the CRT, and from the straight line pattern for strain testing on the left and right of the outermost part of the CRT screen than the pattern for brightness abnormality testing.
The surface displayed inside the CRT screen and the surface
a test pattern generator that generates a test pattern that is integrated with a convergence failure inspection pattern consisting of vertical stripes displayed in the outer direction of a CRT screen;
An observation device for observing a CRT display screen and a display image, and an inspection device for inspecting the display image based on image data inputted by the observation device and reference values stored in advance in a memory,
The display image quality of the CRT display device is inspected using the test pattern.

Next, the difference between the pattern of the present invention and the conventional pattern for television inspection will be explained, and the operation of the present invention will be explained.

The difference between normal TV inspection patterns and the patterns of the present invention is that the main difference is whether the inspection is performed by a human or a machine, and a pattern suitable for the pattern recognition (inspection) ability of each person is used. This is caused by the difference in whether the image displayed on the monitor is a person, like a television, or something that displays text, like a word processor.

Specifically, since the main purpose of regular televisions, etc. is to photograph natural scenery and people rather than to photograph text, it is important that there is no distortion on the entire screen (or people) rather than partial distortion. Since it is necessary that the face (face, etc.) does not appear distorted or unnatural, a large circle is displayed on the entire screen for use in the examination. but,
In devices such as the present invention, in which many characters are displayed on the screen, it is necessary to check that there is no local distortion (the size of the characters is not different between the top and bottom of the screen, and between the right and left sides). is required, and it is not necessary to check that the full-screen circle is not distorted). Therefore, instead of testing using a circle that fills the entire screen, a straight line pattern that is approximately the same as the character spacing displayed vertically and horizontally is displayed, and testing is performed to see if the spacing is constant everywhere.

Also, unlike the TV, which does not use a fan-shaped pattern, for humans, it uses only a certain striped pattern like the present invention, and its shading (the white part and the black part of the stripe) This is because machines are not good at determining the level of resolution by looking at information such as shading of intermediate tones rather than complete 1s and 0s, but machines can do this. In order for humans to see with the naked eye, it is necessary to look at several striped patterns with different intervals (resulting in a fan shape) and check the resolution based on the moire situation (which appears as out of focus). It is. In other words, mechanical inspection as in the present invention does not require a fan-shaped striped pattern with multiple pitches, but simply uses a striped pattern with a constant pitch and observes its shading. The same effect as pattern inspection can be obtained. However, it is difficult for humans to quantitatively understand the difference in shading when visually inspected (with the eyes), so we use moiré as a substitute). As mentioned above, the test pattern centered on straight lines is used for testing as a monitor for displaying text, or for testing a monitor for naturally capturing straight lines (circles) such as a human face. This is the difference.

(f) Examples of the Invention Next, the gist of the present invention will be specifically explained using examples.

FIG. 1 shows a configuration diagram of an embodiment of the present invention, 1
2 is an observation device that observes the display surface of the CRT display device and the CRT outer frame; 3 is an inspection that inspects the display quality of a test pattern using image data obtained by observation device 2; 4 is a test pattern generator that generates a test pattern, and 5 is a control device that controls the observation position and observation field of the observation device 2.

FIG. 2 shows an example of test patterns generated by the test pattern generator 4, including A2, A3,
D6, A7, A9, A10 and B1 to B5 are convergence failure test patterns, C1 and C2 are horizontal nonlinearity test patterns, D1 and D2 are vertical nonlinearity test patterns, F and E1 to E4 is a rectangular pattern for the outer frame of the display screen and distortion inspection, A1,
A4, A5, and A8 are patterns for brightness abnormality inspection.

Convergence failure is caused by the difference between the maximum brightness and minimum volatility of the grid pattern, as disclosed in Japanese Patent Application Laid-Open No. 59-41974 "Method for Inspecting Defocus on CRT Display Surface".
And the ratio of the difference between the maximum brightness and the minimum brightness of the tube surface can be detected by comparing it with a reference value. The convergence state at points other than the corners and center on the CRT screen is intermediate between the convergence states at the corners and center, so
It is sufficient to inspect the center and four corners of the CRT screen as shown in FIG. Inspection is performed using the following combination of test patterns shown in the figure. It is a CRT
Planar pattern on both ends of the top (A1, A4, A5, A8)
If a brightness abnormality occurs when using , it is because the maximum brightness cannot be correctly inspected.

Upper left corner A2, B1 Lower left corner A6, B3 Upper right corner A3, B2 Lower right corner A7, B4 Center A10 (or A9), B5 Nonlinearity abnormalities are determined according to JP-A-59-4383 "CRT Screen Quality Inspection Method" As disclosed in the technical disclosure, the average spacing of the parallel line pattern is calculated for the top, middle, and bottom sections in the vertical direction, and for the left, middle, and right sections in the horizontal direction, and the difference between them is calculated as the reference value. It can be detected by comparison. Furthermore, the nonlinearity of CRT display devices, for example, nonlinearity in the sub-scanning direction, appears biased in one direction as shown in Figure 4 a, but there is also a partial bias as shown in Figure b. Therefore, in this example, as shown in Fig. 2,
Inspection is performed using D1 and D2 and C1 and C2.

Distortions such as pincushion distortion and insufficient display amplitude are
As disclosed in 4383 "CRT Screen Quality Inspection Method", the outer frame of CRT (F shown in Figure 2) and
The rectangle displayed on the CRT (from E1 shown in Figure 2)
The ratio of the corresponding lengths of E4) can be detected by measuring at three locations each in the vertical and horizontal directions and comparing with a reference value for each location.

Abnormal brightness can be detected as disclosed in Japanese Patent Application Laid-Open No. 59-111475 "Inspection Method for CRT Display Screens".
It can be detected by comparing the ratio of the maximum brightness of the left and right sides of a wide pattern displayed at both ends of the CRT screen with a reference value. Brightness abnormalities on CRT screens occur due to scanning aliasing, so they occur for all scanning lines at the left or right edge of the screen, as shown in Figure 5a, and only for some scanning lines, as shown in Figure b. Since this does not occur, it is sufficient to perform the inspection on a portion of the left end and right end. In this example, the inspection pattern is placed on both ends of the CRT screen as a pair of surface patterns (the pair A1 and A4 and the pair A5 and A8 shown in Figure 2).
A brightness abnormality is detected by comparing the brightness of the pair.

The processing of the inspection apparatus of this embodiment for each inspection item will be explained below.

FIG. 6 shows a detailed configuration diagram of the inspection device 3 shown in FIG. 1. 6 is a buffer for storing test pattern data observed by the observation device 2 and AD converted into multiple bits for each pixel; 7 is a convergence failure inspection unit;
Reference numeral 8 denotes a distortion tester, 9 a nonlinearity tester, 10 a brightness abnormality tester, 11 a memory for storing reference values for determination, and 12 a reference value and a calculated value obtained by each tester. This is a determination unit that compares the images and determines the quality of the image.

FIG. 8 shows a detailed configuration diagram of the convergence failure inspection section 7 shown in FIG. 6. The observation device 2 enlarges and observes the test pattern as shown in FIG. 7 under the control of the control device 5, converts it into multi-bit digital data representing multiple gradations for each pixel, and stores it in the buffer 6. Each measuring section, which will be described later, performs measurements based on data stored in the buffer 6 at each measuring point (for example, in FIG. 7a). The planar pattern maximum brightness measuring section 71 measures the maximum brightness of the planar pattern (A10) based on the data of the buffer 6, and the tube surface brightness measuring section 7
2 measures the brightness around the planar pattern (A10), the vertical stripe pattern maximum brightness measurement section 73 and the vertical stripe pattern minimum brightness measurement section 74 respectively measure the maximum and minimum brightness of the vertical stripe pattern (B5), and the subtraction section 75
calculates the brightness difference of the tube surface from the measurement results by the planar pattern maximum brightness measurement section 71 and the tube surface brightness measurement section 72, and the subtraction section 76 calculates the difference in brightness of the tube surface from the measurement results by the vertical striped pattern maximum brightness measurement section 73 and the vertical striped pattern minimum brightness measurement section 74. The brightness difference of the vertical striped pattern is calculated from the result, the dividing unit 77 calculates the ratio of the differences calculated by the subtracting units 75 and 76, and the determining unit 12 uses the ratio calculated by the dividing unit 77 as a reference value in the memory 11. It is determined whether there is poor convergence by comparing with .

FIG. 9 shows a detailed configuration diagram of the distortion inspection section 8 shown in FIG. 6. The binarization processing units 81 and 85 convert the luminance data observed at each of three measurement positions horizontally or vertically on the display screen and stored in the buffer 6 based on different thresholds for outer frame and rectangular pattern detection, respectively. The frame position detection units 82 to 84 detect the left (top), center, and The right (lower) position is detected, and the rectangular position detection units 86 to 88 are respectively binarized by the binarization processing unit 85.
The left (top) of the rectangular pattern (E1 to E4 shown in Figure 2) at each measurement position based on the binary data from
Detects the center and right (bottom) positions (the rectangular pattern includes other inspection patterns inside, so the positions corresponding to the first high brightness area from the top (left) and bottom (right)) are detected. The dividing units 8a to 8c calculate the ratio of the outer frame length to the rectangular length at each measurement position, the subtracting unit 8d calculates the difference between the ratios calculated by the dividing units 8a to 8c, and the determining unit 12 calculates this difference. is compared with a reference value to detect the inclination and pincushion distortion, and the ratios calculated by the dividers 8a to 8c are compared with the reference value to detect insufficient amplitude.

FIG. 10 shows a detailed configuration diagram of the nonlinearity testing section 9 shown in FIG. 6. The binarization processing section 91 is a buffer 6.
The nonlinearity test pattern (D1, D2; C1,
The observation data of C2) is binarized based on a predetermined threshold value, and the upper (left) interval measuring section 92 and the lower (right) interval measuring section 93 binarize the observed data of D1 (or C1) and D2 (or
C2), the average value calculation units 94 and 95 each calculate an average value for the measured line spacing, the subtraction unit 96 calculates the difference between the average values, and the determination unit 12 compares the difference calculated by the subtraction unit 96 with a reference value stored in the memory 11 to determine nonlinearity abnormality.

FIG. 11 shows the brightness abnormality inspection section 10 shown in FIG.
A detailed configuration diagram is shown. When an abnormality in brightness is detected, the observation device 2 enlarges and observes the test pattern as shown in FIG. The left side pattern maximum brightness measurement unit 101 and the right side pattern maximum brightness measurement unit 102 measure A1 and A4 (or A5), respectively, based on the observation data of the brightness abnormality inspection patterns (A1, A4; A5, A8) in the buffer 6. and A8), the subtraction unit 103 calculates the difference between the measured maximum brightness, and the determination unit 12 compares the difference calculated by the subtraction unit 103 with the reference value in the memory 11. to determine brightness abnormality.

(g) Effects of the Invention As explained above, in the conventional case where the inspection is performed by humans, it is necessary to inspect whether the circle that fills the screen is distorted due to the moiré situation, and it is necessary to inspect whether the circle that fills the screen is distorted or not. While it is difficult to judge the resolution by looking at the density, the present invention uses only a striped pattern of a certain pitch to obtain the appearance of the shading. It is possible to conduct electrical inspections accurately and automatically using a , and there is no local distortion when testing as a monitor that displays many characters on the screen, such as in a word processor. It is advantageous to be able to sufficiently inspect the According to the present invention, it is possible to automatically test for multiple types of image quality abnormalities in the display image of a CRT display device using the same test pattern, and it is possible to perform precise testing and improve testing efficiency. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a test pattern used in an embodiment of the present invention, and FIG.
5 to 5 are explanatory diagrams of how image quality abnormalities appear, FIG. 6 is a detailed configuration diagram of the inspection device 3, FIG. 7 is an example of a partially enlarged observation image of a test pattern, and FIG. 8 is a convergence defect inspection unit 7 9 is a detailed configuration diagram of the distortion inspection section 8, FIG. 10 is a detailed configuration diagram of the nonlinearity inspection section 9, and FIG. 11 is a detailed configuration diagram of the brightness abnormality inspection section 10. In the figure, 1 is a CRT display device, 2 is an observation device, and 3
is an inspection device, 4 is a test pattern generator, 5 is a control device, 6 is a buffer, 7 is a convergence failure inspection section,
8 is a distortion test section, 9 is a non-linearity test section, 10 is a brightness abnormality test section, 11 is a memory, 12 is a judgment section, 71
72 is a planar pattern maximum brightness measurement unit, 72 is a tube surface brightness measurement unit, 73 is a vertical striped pattern maximum brightness measurement unit, 7
4 is a vertical striped pattern minimum brightness measurement unit, 75, 76,
8d, 96 and 103 are subtraction units, 77, 8a, 8
b and 8c are dividing units, 81, 85 and 91 are binarization processing units, 82 is an outer frame position left (top) detection unit, 83
is the outer frame position center detection part, 84 is the outer frame position right (bottom)
Detection unit, 86 is rectangle position left (top) detection unit, 87 is rectangle position center detection unit, 88 is rectangle position right (bottom) detection unit, 92 is upper (left) interval measurement unit, 99 is lower (right) 94 and 95 are average value calculation units; 101 is a left-sided pattern maximum brightness measurement unit; 1
02 is a right side pattern maximum brightness measuring section.

Claims (1)

[Claims] 1. In the display image inspection of a CRT display device, a nonlinearity inspection pattern ( D1, D2, C1, C2), and straight line patterns for distortion testing (E1, E2, E3, E4) displayed on the top, bottom, left and right of the outermost edge of the CRT screen.
and is in contact with the straight line patterns for strain testing (E1, E3) displayed on the left and right of the outermost edge on the CRT screen, and is displayed inside the straight line patterns for strain testing (E1, E3) toward the center of the CRT. Planar brightness abnormality inspection patterns (A1, A4, A5, A8), vertical stripes B5 and planes (A9, A10) displayed in the center of the CRT screen, and the outermost CRT of the CRT screen.
Displayed on at least one of both ends of the straight line patterns (E1, E2) for distortion testing displayed at the top and bottom, and
From the straight line patterns for distortion testing (E1, E3) on the left and right of the outermost part of the screen, to the surfaces (A2, A3, A6, A7) that are displayed on the inside of the CRT screen, and the surfaces that are displayed on the outside of the CRT screen on the surfaces that are displayed on the inside of the CRT screen. Vertical stripes (B1, B2, B3,
A test pattern generator that generates a test pattern integrated with a convergence defect inspection pattern consisting of B4), an observation device that observes a CRT display screen and a display image, and an image data input by the observation device and An inspection device for inspecting a display image based on a reference value stored in advance in a memory, and inspecting the display image quality of the CRT display device using the test pattern. Device.