JP2001258054A - Image quality inspection device and detector for center of gravity of luminance used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image quality inspecting device, which uses a CCD camera for picking up an image quality inspection pattern displayed on a screen for inspecting the image quality such as convergence, that can reduce the measurement time at a low cost and accurately measure calculation of center of gravity of luminance. SOLUTION: An installation angle is attached to an object 1 to be inspected and a CCD camera 2 to enhance the measurement accuracy of calculating the luminance gravity center. Furthermore, a frame memory area segmentation unit 7 and a threshold decision unit 11 are used to reduce the effect of luminance shading of a CRT 1, so as to enhance the accuracy of the luminance gravity calculation and thereby inspecting image quality, such as convergence.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image quality inspection device for a display device and a luminance center of gravity inspection device for the image quality inspection device for a display device.

2. Description of the Related Art FIG. 10 is a block diagram of a conventional CRT image quality inspection apparatus. In FIG. 10, a CRT 101 is an object to be inspected and is a display device that displays a test pattern. The CCD camera 102 is an imaging unit that captures an image of a test pattern displayed on the screen of the CRT 101. Further, the CCD camera 102 is positioned on a perpendicular line of the display screen of the CRT 101 and is fixed so as not to rotate. CC
The D camera interface 103 is connected to the CCD camera 10
2 is a device that outputs the image captured in 2 to the frame memory 104. The frame memory 104 is a frame memory for recording an image output from the CCD camera interface 103. The inspection position search processor 105 is a measurement position confirmation unit that searches a luminance level on the frame memory 104 and searches for an inspection position for calculating a luminance center of gravity. The luminance center-of-gravity calculator 106 is the inspection position search processor 1
This is a luminance center-of-gravity detecting device that calculates the luminance center of gravity at each inspection position, which is the search result of the search 05. Brightness centroid result calculator 107
Is a luminance center-of-gravity result calculating means for calculating a relative positional relationship between a plurality of luminance centroids, which is a calculation result of the luminance center-of-gravity calculator 106. The measurement value judgment processor 108 is a measurement value judgment processing means for judging image quality based on the result of the luminance center-of-gravity result calculator 107, and the measurement value judgment result display 109 displays the judgment result of the measurement value judgment processor 108. It is a measurement value judgment result display means. Next, the operation of the CRT image quality inspection apparatus will be described. A lattice test pattern is displayed on the CRT 101 for image quality inspection of the CRT. The CCD camera 102
The whole screen of the test pattern displayed on the CRT 101 is input collectively. The image input by the CCD camera 102 is
The data is recorded in the frame memory 104 through the CCD camera interface 103. Inspection position search processor 105
Searches an inspection position for calculating a luminance center of gravity from data recorded in the frame memory 104. FIG.
A test pattern of a lattice pattern displayed on the CRT is shown, and white circles on the lattice are points specified as inspection positions as a result of the search by the inspection position search processor 105.
From FIG. 11, the positions of all intersections of the lattice pattern are the inspection positions obtained by the inspection position search processor 105. Brightness center of gravity calculator 1
At 06, the luminance center of gravity of the inspection position obtained by the inspection position search processor 105 is calculated. FIG. 12 is a diagram of a pixel of a CCD camera in the vicinity of a vertical line of a lattice pattern in the related art, and
FIG. 4 is a diagram illustrating a luminance level. FIG. 12A shows a lattice pattern displayed on the CRT. FIG. 12B is an enlarged view of a portion K including a part of the vertical line of the lattice pattern in FIG. The rectangular black frame is the outline 42 of the vertical line of the lattice pattern in the range of K. The circles are the pixels of the CCD camera 1, the white circles 40 are the pixels that have not received light, and the black circles 41 are the pixels that have received light. FIG. 12C shows a cross section of a vertical line of the lattice pattern at the luminance level taken in the horizontal direction. When no light is received, the brightness level is low, and when light is received, the brightness level is high. Among the luminance levels equal to or higher than the threshold value set in advance, the position with the highest luminance level is determined as the luminance centroid, and the luminance centroid (H1 to H3) is calculated by the luminance centroid calculator.
To calculate the average value of the luminance centroids of several lines. The luminance centroid of the inspection position obtained from the result of the inspection position search processor 105 is calculated by the luminance centroid calculator 106, and the position of the vertical line or horizontal line at the intersection can be obtained. Luminance centroid result calculator 10
Reference numeral 7 uses the luminance centroid of the computation result of the luminance centroid calculator 106 to calculate the distance between the lines of the displayed grid pattern, the parallelism, and the like. The measurement value determination processor 108 determines the image quality from the calculation result of the luminance centroid result calculator 107,
The determination result is displayed by the measurement value determination result display 109.

When an inspection of a CRT is performed, the inspection is performed based on the measurement result of the luminance centroid at the inspection position. Therefore, it is important to measure the luminance centroid accurately and quickly. However, since the CRT emits light with a phosphor, the outline is not clear in details, and the resolution of the light receiving element cannot be measured accurately with a CCD camera of about 400,000 pixels because the resolution of the light receiving element is insufficient. In some cases, the error in the position measurement accuracy of the vertical line and the horizontal line was large. Also, conventionally, when calculating the luminance centroid, the calculation is performed based on the same threshold value for a plurality of inspection positions.
At the same threshold value, the error in position measurement accuracy may increase due to luminance shading. In FIG.
FIG. 13A shows a lattice pattern displayed on the display surface of the CRT. FIG. 13B is a diagram showing a luminance level on the straight line Y shown in FIG. Where the vertical line of the lattice pattern is included, the luminance level is high, and the portion without the lattice pattern is at a low luminance level. FIG. 13 (c)
FIG. 13D is a diagram in which only the luminance level of the vertical line (white) portion of the lattice pattern is cut out, and FIG. 13D shows the background (black) of the display screen
It is a figure of the brightness level in a part. Luminance shading refers to a phenomenon in which the luminance level in FIG. 13 (c) is higher by X at the center than at both ends, and the luminance level in FIG. 13 (d) is higher by Z at both ends than at both ends. For example, FIG.
As shown in (b), if the thresholds of all the measurement positions are set to the same value, and for example, the threshold value is 1, A0, A1, A7, A
Since the peak of the luminance level of 8 is lower than the luminance level of the threshold 1, the luminance centroid is not measured. When the threshold value is set to 2, all the peaks of the luminance levels A0 to A8 are higher than the threshold value 2. In particular, in the case of A2 to A6, FIG.
(a) than the brightness level of the black part on the display screen,
Threshold 2 is lower. That is, even when it is desired to obtain the luminance centroids for each of A2 to A6, since all the values are equal to or more than the threshold value in A2 to A6, only the highest A4 is measured as the only luminance centroid of A2 to A6. Therefore, the luminance center of gravity cannot be measured accurately. As described above, there is a problem that the error in the position measurement accuracy due to the luminance center of gravity increases due to the setting of the threshold value. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an image quality inspection apparatus and a luminance centroid inspection apparatus capable of measuring a luminance centroid position with high accuracy in an image quality inspection apparatus and a luminance centroid inspection apparatus of a display device and having few errors. Is provided.

According to the present invention, there is provided an image quality inspection apparatus, comprising: an image pickup means for picking up an image of a display device displaying a test pattern for image quality check; and a frame for recording image data inputted by the image pickup means. A memory, using image data recorded in the frame memory, a measurement position confirmation unit that searches for a luminance level to determine an inspection position, and a luminance centroid calculation unit that calculates a luminance centroid of the inspection position.
A luminance barycenter result calculating unit that calculates a relative positional relationship between the plurality of luminance centroids, a measurement value determination processing unit that determines image quality from the luminance barycenter result calculation unit, and a determination result of the measurement value determination processing unit. It has a measurement value determination result display means for displaying, an imaging screen of the imaging means and a display screen of the display device are opposed to each other, and a vertical axis connecting the imaging screen and the display screen is relatively defined as a rotation axis. By rotating the imaging screen, the imaging is performed in a state where the imaging screen is tilted relatively to the display screen. With this configuration, the inspection accuracy is improved because the number of light receiving pixels is increased. In addition, the luminance center of gravity detection device of the present invention includes: an imaging unit that captures an image of a display device displaying a test pattern for image quality inspection; a frame memory that records image data input by the imaging unit; Using image data recorded in the camera, a measurement position confirmation unit that searches for a luminance level to determine an inspection position, and a luminance centroid calculation unit that calculates a luminance centroid of the inspection position; And the display screen of the display device is opposed to each other, and the imaging screen is tilted relative to the display screen by relatively rotating about a vertical axis connecting the imaging screen and the display screen as a rotation axis. It has a configuration in which imaging is performed in a state in which the camera is in a closed state. With this configuration, since the number of light receiving pixels is increased, the measurement accuracy of the luminance centroid is improved. Further, the image quality inspection apparatus according to the present invention includes: an imaging unit for imaging a display device displaying a test pattern for image quality inspection; a frame memory for recording image data input by the imaging unit; Using the image data recorded in the image data, a luminance level is searched, and a measurement position confirmation unit that determines an inspection position, a frame memory area cutout unit that determines a range including the inspection position as a measurement range, and Threshold value calculating means for calculating and calculating a threshold value used in calculating the luminance centroid using the range; and a luminance centroid for calculating the luminance centroid using the threshold value calculated by the threshold value determining means. Calculating means for calculating a relative positional relationship between a plurality of luminance centroids from the luminance centroid; and determining the image quality from the luminance centroid result calculating means. It comprises a measured value judgment processing means, and a measured value judgment result display means for displaying the judgment result of the measured value judgment processing means, and the measurement range for determining the threshold value is obtained by the measurement position confirmation means. As a range that includes one inspection position and the other inspection position does not fall within the measurement range, the measurement range is individually calculated for each inspection position. With this configuration, even if the luminance shading differs at each measurement position, the optimum threshold value can be determined, so that the inspection accuracy is improved. Further, the luminance center-of-gravity detecting device of the present invention includes an image pickup unit for picking up an image of a display device displaying a test pattern for image quality inspection, a frame memory for recording image data input by the image pickup unit, and the frame memory. Using the image data recorded in the image data, a luminance level is searched, and a measurement position confirmation unit that determines an inspection position, a frame memory area cutout unit that determines a range including the inspection position as a measurement range, and Threshold value determining means for calculating and calculating a threshold value used in calculating the luminance centroid using the range;
The luminance center of gravity calculating means for calculating the luminance center of gravity using the threshold value determined by the threshold value determining means and the measurement range for determining the threshold value are one of the ones obtained by the measurement position confirmation means. It is configured that the measurement range is individually calculated for each inspection position as a range including the inspection position and other inspection positions not falling within the measurement range. With this configuration, even if the luminance shading is different at each measurement position, the optimum threshold value can be determined, so that the luminance centroid detection accuracy is improved. Furthermore, in the image quality inspection apparatus according to the present invention, in addition to the configuration according to claim 3, an imaging screen of imaging means and a display screen of the display device are opposed to each other, and a vertical axis connecting the imaging screen and the display screen is provided. By rotating the imaging screen relatively with respect to the rotation axis, the imaging is performed in a state where the imaging screen is relatively inclined with respect to the display screen. With this configuration, since the number of light receiving pixels increases, the accuracy of the image quality inspection improves. Furthermore, in the luminance center-of-gravity detecting device according to the present invention, in addition to the configuration according to claim 4, an imaging screen of imaging means and a display screen of the display device are opposed to each other, and A configuration is provided in which the image is taken in a state in which the imaging screen is relatively inclined with respect to the display screen by relatively rotating the axis with the axis as a rotation axis. With this configuration, the number of light receiving pixels is increased, so that the luminance centroid detection accuracy is improved. Further, the image quality inspection apparatus according to the present invention comprises an image pickup means for picking up an image of a display device displaying a test pattern for image quality check, and a frame memory A for recording image data picked up by the image pickup means.
An affine transformation processor for transforming image data input by the imaging means into image data when the image data is not relatively rotated about a vertical axis of the imaging screen and the display screen as a rotation axis; and A frame memory B for recording image data converted by the detector, a measurement position confirmation unit for searching for a luminance level using the image data recorded in the frame memory B and determining an inspection position; The inter-frame-memory position converter that performs inverse affine transformation to convert the determined inspection position into the position of the frame memory A, and the frame memory B is converted to the frame memory A by the inter-frame memory position converter. A luminance centroid calculating means for calculating a luminance centroid using the inspection position; and a relative position relation of a plurality of luminance centroids from the luminance centroid. Brightness center-of-gravity result calculating means, a measured value determination processing means for determining image quality from the brightness center-of-gravity result calculating means, and a measured value determination result display means for displaying a determination result of the measured value determination processing means, The imaging screen of the imaging unit is opposed to the display screen of the display device, and the imaging screen is rotated by a relative rotation about a vertical axis connecting the imaging screen and the display screen. Image pickup in a state of being relatively tilted with respect to. This configuration increases the number of light receiving pixels,
Further, by using two frame memories, the calculation speed is improved, and the accuracy and the inspection speed of the image quality inspection are improved. Further, the luminance center-of-gravity detecting device of the present invention includes: an image pickup means for picking up an image of a display device displaying a test pattern for image quality inspection; a frame memory A for recording image data picked up by the image pickup means; Means for converting the image data input by the means into image data when the image screen and the display screen are not relatively rotated about the vertical axis of the display screen as a rotation axis; and A frame memory B for recording the image data obtained by the measurement, a measurement position confirming means for retrieving a luminance level by using the image data recorded in the frame memory B and determining an inspection position, and the inspection determined by the frame memory B. A frame memory position converter for performing an inverse affine transformation to convert a position into a position of the frame memory A; A luminance barycenter calculating means for calculating a luminance barycenter using the inspection position converted from the frame memory B to the frame memory A by the converter, wherein an image screen of the image pickup means is opposed to a display screen of the display device. And a configuration in which the imaging screen is imaged in a state in which the imaging screen is relatively inclined with respect to the display screen by relatively rotating about a vertical axis connecting the imaging screen and the display screen as a rotation axis. With this configuration, the number of light receiving pixels increases, and the use of two frame memories improves the calculation speed, thereby improving the accuracy of image quality inspection and the inspection speed. Further, in addition to the configuration according to claim 7, the image quality inspection apparatus according to the present invention further includes a frame memory area extracting means for extracting the position calculated by the measurement position confirming means as image data, and an image output from the frame memory area extracting means. Threshold value determining means for determining a threshold value for calculating the luminance center of gravity from the obtained data,
The measurement range for determining the threshold value by the frame memory area cutout means includes one inspection position obtained by the operation of the measurement position confirmation means, and another inspection position falls within the measurement range. This measurement range is individually calculated for each inspection position as a non-existent range, and thereafter, the luminance centroid is calculated using the threshold value determined for each measurement range by the threshold value determination means. It is. With this configuration, the number of light receiving pixels is increased, the optimum threshold value can be determined even if the luminance shading differs at each measurement position, and the calculation speed can be improved by using two frame memories. Speed will be improved. Furthermore, the luminance center-of-gravity inspection apparatus of the present invention, in addition to the configuration according to claim 8, further includes a frame memory area extracting section for extracting the position calculated by the measurement position confirming section as image data, and a frame memory area outputting section. Threshold data for calculating a luminance center of gravity from the obtained data, and a measurement range for determining a threshold value by the frame memory area extracting means is determined by the measurement position confirmation. The measurement range is individually calculated for each inspection position as a range including one inspection position obtained by the operation of the means and not including the other inspection position in the measurement range. The luminance center of gravity is calculated using the threshold value determined for each of the measurement ranges by the determination means. With this configuration,
Since the number of light receiving pixels increases and the optimal threshold value can be determined even if the luminance shading differs at each measurement position, the operation speed is improved by using two frame memories.
The measurement accuracy of the luminance center of gravity and the inspection speed are improved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of a first embodiment of the present invention. Figure 2 shows CRT1
And the positional relationship between the CCD camera 2 and the camera. From FIG. 2, the CCD camera 2 is rotated about an axis perpendicular to the display portion,
It is fixed in an inclined state. As shown in FIG. 1, in this image quality inspection apparatus, the CRT 1 displays a test pattern for performing an image quality inspection on an inspection target. The CCD camera 2 captures an image of the test pattern displayed on the CRT 1. As shown in FIG. 2, the CCD camera 2 is in a direction (Z axis) perpendicular to the display surface (on the XY plane) of the CRT 1, and the CCD camera 2 is rotated around the Z axis and tilted. Fixed (angled). The camera interface 3 outputs an image input by the CCD camera 2 to a frame memory A4, and records the image in the frame memory A4. The affine transformation processor 5 performs affine transformation processing for correcting the input real image data of the CCD camera to an angle opposite to that of the CCD camera. The frame memory B6 records the image data subjected to the affine transformation processing. The inspection position search processor 9 determines an inspection position by searching for a luminance level on the frame memory B6. Next, the inter-frame memory position converter 10 performs conversion between the coordinate systems from the frame memory B6 to the frame memory A4 in order to make the measurement position searched in the frame memory B6 correspond to the corresponding position in the frame memory A4. The frame memory area extractor 7 extracts data on the frame memory A4 into a range of a size that allows an optimum threshold value to be set for each measurement position. The threshold value determiner 11 determines an optimum threshold value of the image for each range extracted by the frame memory area extractor 7. The luminance center of gravity calculator 8 with the line averaging process is
The luminance center of gravity is calculated for the specified line in the frame memory A4, and the average value processing is performed. The brightness centroid result calculator 13 performs a calculation using the calculation result of the brightness centroid calculator 8 with the line averaging process. The measurement value determination processor 14
The image quality is determined from the result of the luminance centroid result calculator 13. The measurement value judgment result display 15 displays the judgment result of the measurement value judgment processor 14. The operation of the CRT image quality inspection apparatus will be described with reference to the drawings. FIG. 3 shows the flow of the image processing of the present invention. The CRT 1 displays a grid test pattern.
The angled CCD camera 2 (angled at 5 ° in the first embodiment of the present invention) collectively captures the entire screen of the displayed test pattern. FIG.
As shown in (a), the captured image from the CCD camera 2 at an angle displays a lattice pattern in an oblique state.
The captured image is recorded in the frame memory A4 through the CCD camera interface 3 and is input to the affine transformation processor 5 at the same time. The frame A4 in which the lattice pattern in the diagonal state is input records an image in the diagonal state and performs an operation. The affine transformation processor 5 corrects the input captured image (the angled grid pattern in an oblique state) to an unangled state (FIG. 3 (b)), and converts the unangled image data. The data is recorded in the frame memory B6.
The inspection position search processor 9 searches the position of the image data designated by the inspection position search processor 9 (for example, the intersection of the lattice pattern) from the image data which is not angled and recorded in the frame memory B6. When the intersection of diagonal lattice patterns is searched by one frame memory using the inspection position search processor, the measurement is more complicated (for example, a lattice pattern that is not diagonal) than when a non-diagonal lattice pattern is measured. When checking the intersection of, first check the vertical line and the horizontal line, you can check the location of the intersection by checking one place, but if it is in a diagonal state, measure the vertical and horizontal sides and confirm the intersection at the end) It takes time to measure. Therefore, if two frame memories A and B are used, the intersection point can be accurately confirmed in the frame memory B by searching for the intersection point from the lattice pattern that is not oblique in the affine transformation processing. In the frame memory A, the intersection obtained by the frame memory B is converted by the inverse affine transformation, and the luminance center of the inspection position alone is measured, so that the inspection speed can be improved. In the first embodiment of the present invention, the positions (white circles) of all the intersections of the grid pattern are determined by the inspection position search processor. In this case, the inspection position search processor 9 searches for 25 grid pattern intersections, and sets the positions of the intersections to (Xi, Yi) i = 1 to 1.
25 (FIG. 3C). Frame memory position converter 1
0 is the processing result (Xi, Yi) of the inspection position search processor 9
For i = 1 to 25, the coordinate system of the frame memory B6 is converted to the coordinate system (Xoi, Yoi) of the frame memory A4 (FIG. 3D). As described above, using two frame memories is effective in improving the accurate measurement position and the inspection speed. The frame memory area extractor 7 determines a measurement range for determining a threshold value at each inspection position based on the result (Xoi, Yoi) i = 1 to 25 of the inter-frame-memory position converter 10.
The method for setting the cutout range is as follows. First, the cutout size (measurement range) is set at the center of the test position (intersection point) on the converted memory frame A4, and does not include other test positions (intersection points). Set to the size of the range. Since the luminance center of gravity cannot be calculated when another intersection is entered, the intersection (peak having a high luminance level) is one in each measurement range. After that, the frame memory A
4 is a threshold value determiner 1
Output to 1. The threshold value determiner 11 calculates a threshold value at each inspection position in the range set by the frame memory area extractor 7 so that another inspection position does not enter the frame. At each inspection position, extra luminance such as the background is discarded, and the luminance level as low as possible (for example, FIG.
3 (d), the threshold value of the background (black) of the lattice pattern (the level close to the luminance level W) is determined. The luminance shading varies depending on the inspection position. However, this method can reduce the influence of the luminance shading and can perform measurement, thereby improving the measurement accuracy. The luminance center of gravity calculation unit 8 with the line averaging process calculates the luminance center of gravity based on the image data of each of the 25 areas created by the frame memory area extractor 7 and the threshold value determined by the threshold value determiner 11. FIG. 4 shows a pixel diagram of a CCD camera and a luminance level near a vertical line of a lattice pattern. FIG. 4A shows an oblique lattice pattern captured by the CCD camera. FIG. 4B is an enlarged view of a portion K including a part of the vertical line of the lattice pattern in FIG. The black frame of the parallelogram is the outline 42 of the vertical line of the lattice pattern. The circles are the pixels of the CCD camera, the white circles 40 are the pixels that are not receiving light from the CCD camera, and the black circles 41 are the pixels that are receiving light. FIG. 4C shows a horizontal cross section of the luminance level of the vertical line of the lattice pattern. The portion not receiving light has a low brightness level, and the portion receiving light has a high brightness level. A position having the highest luminance level among luminance levels equal to or higher than a preset threshold value is set as a luminance center of gravity. FIG. 5 shows a diagram in which one vertical line of a lattice pattern is received depending on whether or not the CCD camera 2 is rotated. When the CCD camera 2 does not rotate, the number of pixels received by the CCD camera is four in one horizontal line. However, when the angle of the CCD camera is 5 °, the number of received pixels is
There are five horizontal lines. When the angle is set in this manner, the number of pixels received by the CCD camera increases, so that the sensitivity is improved and the measurement accuracy of the luminance center of gravity is improved. The luminance centroid calculator 8 with the line averaging process calculates the luminance centroids of the G1 to G9 lines shown in FIG. 4 and determines that the luminance centroid of the vertical line exists at a position corresponding to the average value of the horizontal positions of the luminance centroids. I do. Also, the horizontal line is determined in the same manner. As described above, the intersection can be calculated from the luminance centroids of the vertical and horizontal lines near each intersection of the grid pattern, and this is set as the position of the intersection. Thereafter, a plurality of image quality inspections are performed using the positions of the intersections. FIG. 6 shows an example of the image quality inspection method. FIG. 6 (a),
(b) is a method of measuring the parallelism of a vertical line, and inspects left and right bulges and dents. Specifically, distance differences E and F on the X-axis at the intersections 60, 61 and 62, 63 indicated by white circles are calculated. FIG. 6C shows a measuring method for calculating the distance between the intersections. The distance G between the intersections in the horizontal direction and the vertical direction is calculated, and it is checked whether the distances between the intersections are the same or different. FIG. 6D shows a measurement method for obtaining the degree of distortion of the outermost contour of the test pattern. Four intersections 64, 65, 6
Using the intersections 6, 67, straight lines facing each other (for example, a straight line connected at intersections 64 and 65 and a straight line connected at intersections 66 and 67) are parallel or have the same side length. Inspection of whether or not. The measured value determination processor 14 determines the image quality from the result of the luminance centroid result calculator 13,
The measurement value judgment result display 15 displays the result of the measurement value judgment processor 14. As described above, the CCD camera 2 and the CRT
1, the measurement accuracy is improved, and the measurement speed is improved by using two frame memories, the frame memory A4 and the frame memory B6. Vessel 1
By using 1, even if there is an influence of luminance shading for each measurement position, an optimum threshold value can be determined and measurement accuracy is improved. Thus, with this configuration, the measurement accuracy of the luminance center of gravity is improved and the speed of the arithmetic processing is improved. Next, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 7 shows a block diagram of the second embodiment of the present invention. The description of the same components as those of the above-described embodiment will be omitted. A comparison between the block diagram of the first embodiment of the present invention of FIG. 1 and the second embodiment shows that the configuration includes an affine transformation processor 5, a frame memory B6, an inspection position search processor 9, and a frame memory. The position converter 10, the frame memory area extractor 7, and the threshold value determiner 11 are different.
Although the speed of the arithmetic processing cannot be improved as compared with the configuration of the conventional apparatus, the measurement accuracy can be improved because the CCD camera 2 positioned in the vertical direction with respect to the display screen can perform imaging while rotating and tilting. Can be improved. Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 8 shows a block diagram of the third embodiment of the present invention. The description of the same components as those of the above-described embodiment will be omitted. Comparing the block diagram of the first embodiment of the present invention in FIG. 1 with the third embodiment, the affine transformation processor 5, the frame memory B6, and the inter-frame memory position converter 10 are different in configuration. Compared with the conventional configuration of FIG. 10, the configuration of the frame memory area extractor 7 and the threshold value determiner 11 is added, and the inspection position is determined by the inspection position search processor 9, and the inspection position is stored in the frame memory area. The cutout device 7 and the threshold value determination device 11 can determine an appropriate threshold value at each intersection and perform calculations with less influence of luminance shading, thereby improving measurement accuracy. Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 9 shows a block diagram of the fourth embodiment of the present invention. The description of the same components as those of the above-described embodiment will be omitted. Comparing the block diagram of the first embodiment of the present invention in FIG. 1 with the fourth embodiment, the frame memory area extractor 7 and the threshold value determiner 11 are different in configuration. Compared to the conventional configuration of FIG. 10, the rotating CCD camera 2
The configuration of the frame memory B, the affine transformation processor, and the position converter between frame memories is further added. As a result, the sensitivity is improved, and the operation speed is also improved by using two frame memories, so that the measurement accuracy and the operation speed can be improved as compared with the conventional product. Furthermore, the CRT and CCD camera are angled,
After extracting a small area from the frame memory A using two frame memories and a frame memory area extractor and setting an optimal threshold value, the luminance center of gravity is calculated with high accuracy under the condition that is hardly affected by the luminance shading of the CRT. Thus, the image quality of the display device can be inspected with high accuracy. Note that CR
Although the angle between T1 and the CCD camera 2 is set, the angle may be any angle as long as the CCD camera 2 can collectively input images for inspection. Although the imaging unit is angled, the same effect can be obtained even if the imaging unit is not angled and the display device as an object to be measured is angled.

As described above, according to the present invention, the CRT and the CCD camera are angled in order to measure the luminance center of gravity accurately and promptly, and to improve the measurement accuracy of the luminance center of gravity and the accuracy of image quality inspection. Even if a conventional CCD camera is used, the sensitivity can be increased and the measurement accuracy of the inspection device can be improved. Also,
The CRT and the CCD camera are angled, two frame memories are used, one frame memory B is used to search for the inspection position, and the result is used to calculate the luminance barycenter from the data A of the other frame memory. Thus, the calculation speed can be improved as compared with the case where the recording calculation is performed by one memory.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 shows a CRT and a CRT according to the first embodiment of the present invention.
Diagram showing positional relationship of CD camera

FIG. 3A is an explanatory diagram showing an image stored in a frame memory A according to the first embodiment of the present invention. FIG. 3B is an explanatory diagram showing an image subjected to affine processing according to the first embodiment of the present invention. (C) An explanatory diagram of an image showing an inspection position confirmation state according to the first embodiment of the present invention. (D) An explanatory diagram showing a coordinate-transformed image according to the first embodiment of the present invention. (E) The present invention Explanatory diagram showing the flow of image processing according to the first embodiment of the present invention.

FIG. 4 (a) CC in the first embodiment of the present invention
Explanatory diagram showing a lattice pattern in an oblique state captured by a D camera. (B) Enlarged view of a K portion including a part of a vertical line of a lattice pattern captured by a CCD camera according to the first embodiment of the present invention. FIG. 3 is an explanatory view of a horizontal cross section of a luminance level of a vertical line of a lattice pattern captured by a CCD camera according to the first embodiment of the present invention.

FIG. 5: CCD depending on whether or not the CCD camera is angled
Figure near the vertical line of the grid pattern received by the camera pixels

FIG. 6A is a diagram showing left and right bulges when the parallelism of a vertical line is measured in the first embodiment of the present invention. FIG. 6B is a diagram showing the vertical bulge in the first embodiment of the present invention. FIG. 3C is a diagram showing the left and right dents when measuring the parallelism. FIG. 3C is a schematic diagram of a measuring method for obtaining a distance between intersections according to the first embodiment of the present invention. Schematic diagram of a measurement method for determining the degree of distortion of the outermost contour of a test pattern in a form

FIG. 7 is a block diagram of a second embodiment of the present invention.

FIG. 8 is a block diagram of a third embodiment of the present invention.

FIG. 9 is a block diagram of a fourth embodiment of the present invention.

FIG. 10 is a block diagram of a conventional CRT image quality inspection apparatus.

FIG. 11 is a diagram showing an inspection position as a search result of the inspection position search processor.

12A is an explanatory view showing a lattice pattern in an oblique state captured by a conventional CCD camera. FIG. 12B is an enlarged view of a K portion including a part of a vertical line of the grid pattern captured by a conventional CCD camera. (C) Explanatory drawing with the cross section of the luminance level of the vertical line of the lattice pattern imaged by the conventional CCD camera taken in the horizontal direction

13A is a diagram showing a lattice pattern displayed on the display surface of a CRT. FIG. 13B is a diagram showing a luminance level on a straight line Y on the lattice pattern. FIG. 13C is a vertical line (white) portion of the lattice pattern. (D) Diagram of luminance level in background (black) part of display screen

[Explanation of symbols]

 Reference Signs List 1 CRT 2 CCD camera 3 Camera interface 4 Frame memory A 5 Affine transformation processor 6 Frame memory B 7 Frame memory area extractor 8 Luminance centroid calculator with line averaging processing 9 Inspection position search processor 10 Frame memory position converter 11 Threshold value determiner 13 Average brightness centroid result calculator 14 Measured value judgment processor 15 Measured value judgment result display 20 Luminance centroid detection device 30 Image quality inspection device

Claims (10)

[Claims] An image pickup means for picking up an image of a display device displaying a test pattern for image quality inspection, a frame memory for recording image data input by the image pickup means, and an image recorded in the frame memory. Using the data, a measurement position confirmation unit that searches for a luminance level to determine an inspection position, a luminance center calculation unit that calculates a luminance centroid of the inspection position, and calculates a relative positional relationship between the plurality of luminance centroids. Brightness centroid result calculation means, measurement value judgment processing means for judging image quality from the luminance centroid result calculation means, and measurement value judgment result display means for displaying a judgment result of the measurement value judgment processing means, The imaging screen of the imaging unit and the display screen of the display device are opposed to each other, and are relatively rotated about a vertical axis connecting the imaging screen and the display screen as a rotation axis. An image quality inspection apparatus that performs imaging in a state where the imaging screen is inclined relative to the display screen. 2. An image pickup means for picking up an image of a display device displaying a test pattern for image quality inspection, a frame memory for recording image data inputted by the image pickup means, and an image recorded in the frame memory. Using the data, a measurement position confirmation unit that searches for a luminance level to determine an inspection position, and a luminance centroid calculation unit that calculates a luminance centroid of the inspection position, wherein the imaging screen of the imaging unit and the display device The display screens are opposed to each other, and the image is captured in a state in which the imaging screen is relatively tilted with respect to the display screen by relatively rotating about a vertical axis connecting the imaging screen and the display screen as a rotation axis. Luminance center of gravity detection device. 3. An image pickup means for picking up an image of a display device displaying a test pattern for image quality inspection, a frame memory for recording image data inputted by the image pickup means, and an image recorded in the frame memory. Using the data, a luminance level is searched, a measurement position confirmation unit that determines an inspection position, a frame memory area extracting unit that determines a range including the inspection position as a measurement range, and a luminance using the measurement range. Threshold value determining means for calculating and calculating a threshold value used in calculating the center of gravity; luminance centroid calculating means for calculating a luminance centroid using the threshold value calculated by the threshold value determining means; Brightness centroid result calculating means for calculating a relative positional relationship between the plurality of luminance centroids from the centroid;
A measurement value judgment processing means for judging image quality from the luminance center-of-gravity result calculation means; and a measurement value judgment result display means for displaying a judgment result of the measurement value judgment processing means. The range includes one inspection position obtained by the measurement position confirmation unit, and the measurement range is individually calculated for each inspection position as a range in which another inspection position does not fall within the measurement range. An image quality inspection apparatus characterized by the above-mentioned. 4. An image pickup means for picking up an image of a display device displaying a test pattern for image quality inspection, a frame memory for recording image data input by the image pickup means, and an image recorded in the frame memory. Using the data, a luminance level is searched, a measurement position confirmation unit that determines an inspection position, a frame memory area extracting unit that determines a range including the inspection position as a measurement range, and a luminance using the measurement range. Threshold value calculating means for calculating a threshold value used in calculating the center of gravity, and luminance center calculating means for calculating a luminance center of gravity using the threshold value calculated by the threshold value determining means. The measurement range for determining the threshold value includes one inspection position obtained by the measurement position confirmation means, and a range in which another inspection position does not fall within the measurement range. A luminance center of gravity detecting apparatus for individually calculating the measurement range for each inspection position. 5. The imaging device according to claim 1, wherein an imaging screen of the imaging unit and a display screen of the display device face each other, and the imaging is performed by relatively rotating a vertical axis connecting the imaging screen and the display screen as a rotation axis. The image quality inspection apparatus according to claim 3, wherein imaging is performed in a state where a screen is tilted relative to the display screen. 6. An image pickup apparatus according to claim 1, wherein an image pickup screen of said image pickup means and a display screen of said display device are opposed to each other, and said image pickup is performed by relatively rotating a vertical axis connecting said image pickup screen and said display screen as a rotation axis. 5. The luminance gravity center detecting device according to claim 4, wherein the imaging is performed in a state where the screen is tilted relatively to the display screen. 7. An image pickup means for picking up an image of a display device displaying a test pattern for image quality inspection, a frame memory A for recording image data picked up by the image pickup means,
An affine transformation processor for transforming the image data input by the imaging means into image data when the image screen and the display screen are not relatively rotated about a vertical axis as the rotation axis; and the affine transformation processor. A frame memory B for recording the obtained image data, a measurement position confirmation unit for searching for a luminance level using the image data recorded in the frame memory B to determine an inspection position, and An inter-frame memory position converter that performs inverse affine transformation to convert an inspection position into the position of the frame memory A; and an inspection position converted from the frame memory B to the frame memory A by the inter-frame memory position converter. A luminance centroid calculating means for calculating a luminance centroid using the luminance centroid; and calculating a relative positional relationship between a plurality of luminance centroids from the luminance centroid. Brightness centroid result calculation means, measurement value judgment processing means for judging image quality from the luminance centroid result calculation means, and measurement value judgment result display means for displaying a judgment result of the measurement value judgment processing means, The imaging unit has an imaging screen and a display screen of the display device facing each other,
In addition, an image quality inspection apparatus that relatively rotates about a vertical axis connecting the imaging screen and the display screen as a rotation axis to image the imaging screen in a state of being relatively tilted with respect to the display screen. 8. An image pickup means for picking up an image of a display device displaying a test pattern for image quality inspection, a frame memory A for recording image data picked up by the image pickup means,
An affine transformation processor for transforming the image data input by the imaging means into image data when the image screen and the display screen are not relatively rotated about a vertical axis as the rotation axis; and the affine transformation processor. A frame memory B for recording the obtained image data, a measurement position confirmation unit for searching for a luminance level using the image data recorded in the frame memory B to determine an inspection position, and An inter-frame memory position converter that performs inverse affine transformation to convert an inspection position into the position of the frame memory A; and an inspection position converted from the frame memory B to the frame memory A by the inter-frame memory position converter. Brightness center of gravity calculation means for calculating a brightness center of gravity using the image pickup means, wherein the image pickup means includes an image pickup screen and a display image of the display device. Is a luminance center of gravity that is opposed to, and captures the imaging screen in a state of being relatively tilted with respect to the display screen by relatively rotating about a vertical axis connecting the imaging screen and the display screen as a rotation axis. Detection device. 9. A frame memory area extracting means for extracting a position calculated by the measurement position confirming means as image data, and a threshold value for calculating a luminance centroid from data output from the frame memory area extracting means. And a measurement range for determining a threshold value by the frame memory area cutout means includes one inspection position obtained by the operation of the measurement position confirmation means, and another inspection position. Is calculated as a range that does not fall within the measurement range, and the measurement range is individually calculated for each inspection position, and the brightness center of gravity is calculated using the threshold value determined for each measurement range by the threshold value determination means. The image quality inspection apparatus according to claim 7, further comprising means. 10. A frame memory area extracting means for extracting the position calculated by the measurement position confirming means as image data, and a threshold value for calculating a luminance centroid from data outputted from the frame memory area extracting means. And a measurement range for determining a threshold value by the frame memory area cutout means includes one inspection position obtained by the operation of the measurement position confirmation means, and A luminance in which the inspection position is not included in the measurement range, the measurement range is individually calculated for each inspection position, and the luminance center of gravity is calculated using the threshold value determined for each measurement range by the threshold value determination means. 9. The luminance center of gravity inspection apparatus according to claim 8, further comprising a center of gravity calculation means.