JP2006125895A - Flat panel display inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct fogging generated in a picked-up image to recognize a defect accurately. <P>SOLUTION: A known image 31 of a flat panel display is imaged by a camera to acquire a concentration value in camera coordinates 35 corresponding to each picture element position. Each coordinate position of the corresponding camera coordinates is correlated with FPD coordinates 41 corresponding to the each picture element position of the flat panel display to form a coordinate correspondence table 42. The coordinates are found therein over up to a value smaller than a decimal point based on the concentration value, coordinates having the same value in a figure smaller than the decimal point are collected to form subpixel coordinates 51, 52 the value by the value, and a neighboring image concentration distribution is formed in every of the subpixel coordinates. The concentration value in the camera coordinates for inspection acquired in the inspection is transformed into a corresponding coordinates for the inspection corresponding to the each pixel position of the flat panel display, based on the correspondence table 41, and an estimated image corresponding to a luminescent brightness of the flat panel display is formed based on the neighboring concentration distribution to inspect the defect. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a flat panel display inspection apparatus for inspecting point defects generated in a flat panel display such as a plasma display or a liquid crystal display.

  Conventionally, when inspecting a flat panel display such as a plasma display or a liquid crystal display, a flat panel display inspection apparatus has been used.

  When inspecting point defects with this flat panel display inspection device, a camera having a resolution that is at least twice the resolution of the flat panel display (4 times the area ratio) is used, and the lens is sharp. It was requested.

  However, in such a flat panel display inspection apparatus, when a low-resolution camera is used, one pixel of the flat panel display appears in several pixels in the camera image and is captured as a blurred image. One defect is recognized as a plurality of defects.

  The present invention has been made in view of such a conventional problem, and is a flat panel that can correct blurring in a captured image and perform accurate defect recognition even with a relatively low-resolution camera. An object of the present invention is to provide a display inspection apparatus.

  In order to solve the above problems, in the flat panel display inspection apparatus of the present invention, in the flat panel display inspection apparatus for detecting point defects from the image of the flat panel display imaged by the camera, the display position of the flat panel display is determined. The point-like bright spots whose coordinates are known are displayed at a predetermined interval, and the image of the displayed known image is captured by a camera, and the density value at the camera coordinates corresponding to each pixel position in the camera is obtained. An image pickup means to be acquired and a coordinate table of the camera coordinates corresponding to the FPD coordinates indicating each pixel position of the flat panel display are obtained up to a value after the decimal point based on the density value at each coordinate position. In the correspondence table creation means to be created and the coordinate position of the camera coordinate indicated by the FPD coordinate, An image processing unit for forming sub-pixel coordinates composed of the lower values having the same value, and forming a neighborhood image density distribution for each sub-pixel coordinate, and displaying an inspection image on the flat panel display Inspection image imaging means for capturing an image of an inspection image with the camera and obtaining a density value at an inspection camera coordinate corresponding to each pixel position in the camera, and the density value at the inspection camera coordinate Coordinate conversion means for converting to inspection corresponding coordinates corresponding to each pixel position of the flat panel display based on the correspondence table, and light emission of the flat panel display from the density value and the neighboring density distribution at the inspection corresponding coordinates Estimated image forming means for forming an estimated image corresponding to luminance; and point defect detecting means for detecting point defects using the estimated image. To have.

  That is, when inspecting the flat panel display, as a previous step, the luminescent spots are displayed at predetermined intervals on the flat panel display with the coordinates of the display position being known. After capturing an image of a known image with a camera and obtaining a density value at camera coordinates corresponding to each pixel position in the camera, the coordinates of the camera coordinates corresponding to FPD coordinates indicating each pixel position of the flat panel display Based on the density value in the camera coordinates, the position is calculated to a value after the decimal point, and a correspondence table is created. At this time, in the known image, since the coordinates of the display position of the bright spot to be displayed are known, values between the bright spots can be interpolated.

  Then, at the coordinate position of the camera coordinates indicated by the FPD coordinates, sub-pixel coordinates composed of the same values after the decimal point are formed, and a neighborhood image density distribution is formed for each sub-pixel coordinate. .

  At the time of inspection, the inspection image is displayed on the flat panel display, and the image of the inspection image is captured by the camera, and after obtaining the density value at the inspection camera coordinates corresponding to each pixel position in the camera, The density value at the inspection camera coordinates is converted into inspection corresponding coordinates corresponding to each pixel position of the flat panel display based on the correspondence table. Then, an estimated image corresponding to the light emission luminance of the flat panel display is formed from the density value at the corresponding coordinates for inspection and the neighborhood density distribution, and a point defect is detected from the estimated image.

  For this reason, even if one pixel on the flat panel display appears in a plurality of pixels in the camera image and is acquired as a blurred image, the blur is corrected in the estimated image.

  As described above, in the flat panel display inspection apparatus of the present invention, even when a blurred image is acquired by the camera, the defect inspection can be performed using the estimated image in which the blur is corrected. .

  Therefore, even when a relatively low-resolution camera is used, it is possible to correct blurring that occurs in the captured image and perform accurate defect recognition. Accordingly, it is possible to use a camera having a relatively low resolution in terms of lens characteristics and CCD camera characteristics.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a flat panel display inspection apparatus 1 according to the present embodiment. The flat panel display inspection apparatus 1 inspects a point defect generated in a flat panel display 2 such as a plasma display or a liquid crystal display. It is a device to do.

  The flat panel display inspection apparatus 1 is mainly configured by a computer 11 that performs image processing, and a camera 13 is connected to the computer 11 via a camera interface 12. The computer 11 is connected to a flat panel display 2 to be inspected, and is configured to output an image corresponding to a signal from the computer 11.

  Further, a filter device 21 is connected to the computer 11, and the filter device 21 is disposed between the lens 22 of the camera 13 and the flat panel display 2. Thereby, by controlling the filter device 21 with a control signal from the computer 11, the camera 13 can acquire an image that passes through a neutral density filter and a color filter and an image that does not pass through each filter. Has been.

  The computer 11 is configured to operate in accordance with a stored program, processes an image acquired by the camera 13 to detect a point defect generated in the flat panel display 2, and determines the position of the other It is configured so that it can be output to a device or a monitor.

  The operation of the present embodiment according to the above configuration will be described with reference to the flowchart shown in FIG.

  That is, when the flat panel display 2 is inspected, as a previous step, a known image 31 as shown in FIG. 3 is displayed on the flat panel display 2 by the output from the computer 11, and the image is used for inspection. The camera 13 takes an image (S1). As the known image 31 (A (i, j)), a lattice point image 33 having a central pixel in a 3 × 3 pixel region as a bright point 32 is represented by the i direction which is the horizontal direction in the figure and the vertical direction in the figure. The position coordinates (i, j) at which each grid point image 33 is displayed are composed of images provided every 4 pixels (or 8 pixels) in the j direction (only one grid point image 33 is shown). It is known in the computer 11. Thereby, the density value at the camera coordinates 35 (B (i, j)) corresponding to each pixel position in the camera 13 is acquired.

  Then, the FPD coordinate 41 (C (x, y)) corresponding to each pixel position of the flat panel display 2 and the camera coordinate 35 (B (i, j) corresponding to each FPD coordinate position (x, y) are provided. ) Is associated with each other to form a coordinate correspondence table 42 (S2). As an example, a method of obtaining coordinates on each grid point image 33 in the camera coordinates 35 up to a value after the decimal point based on the density value, and storing the value at each coordinate position of the FPD coordinates 41. Is mentioned. At this time, since the coordinates of the display position of the bright spot 32 to be displayed in the known image 31 are known, the values between the bright spots 32 can be obtained by interpolation. At each coordinate position in the camera coordinate 35 stored in each coordinate position of the FPD coordinate 41 obtained in this way, the ones having the same value after the decimal point are collected, and the subpixel coordinates 51, 52,. .., And the density distribution H (k, p, q) of the neighborhood image density distribution in which the neighborhood density values are stored separately for each subpixel coordinate 51, 52,... ).

  Next, an inspection image is displayed on the flat panel display 2, and an image of the inspection image is captured by the camera 13, and a density value at the inspection camera coordinates corresponding to each pixel position in the camera 13 is acquired. After (corresponding to the camera coordinates described above), the density value at the inspection camera coordinates is converted into inspection corresponding coordinates corresponding to each pixel position of the flat panel display 2 based on the correspondence table 42 (S4). The initial value of the estimated image 61 (D (x, y)) having the same number of pixels as that of the flat panel display 2 is set (S5).

  The estimated density 61 is combined with the neighborhood density distribution (weight W) at the subpixel coordinates 51, 52,... To form a combined image 71 (E (x, y)) (S6). In the image 71 and the inspection image input by the camera, the density on the estimated image 61 is changed so that the density at each location matches (S7), and the above steps S6 to S7 are repeated several times. This operation is shown in Equation 75 of FIG.

  Thereby, even if one pixel on the flat panel display 2 appears in a plurality of pixels in the camera image and is acquired as a blurred image, the blur can be corrected in the estimated image.

  Then, a point defect is detected from this estimated image (S8). As described above, even when an image blurred by the camera 13 is acquired, the defect inspection can be performed using the estimated image obtained by correcting the blur.

  Therefore, even when the camera 13 having a relatively low resolution is used, it is possible to correct the blur generated in the captured image and perform accurate defect recognition. As a result, the camera 13 having a relatively low resolution can be used for the lens characteristics and the CCD camera characteristics.

It is a block diagram which shows one embodiment of this invention. It is a flowchart which shows the operation | movement of the embodiment. It is a flowchart which shows the operation | movement of the embodiment. 4 is an equation showing the operation of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flat panel display inspection apparatus 2 Flat panel display 11 Computer 13 Camera 31 Known image 32 Bright spot 33 Grid point image 35 Camera coordinate 41 FPD coordinate 42 Coordinate correspondence table

Claims (1)

In the flat panel display inspection device that detects point defects from the image of the flat panel display imaged by the camera,
Point-like bright spots whose display position coordinates are known are displayed on the flat panel display at a predetermined interval, and the displayed image of the known image is captured by a camera, corresponding to each pixel position in the camera. Imaging means for obtaining density values at the camera coordinates,
Correspondence table creation means for creating a correspondence table by obtaining the coordinate position of the camera coordinate corresponding to the FPD coordinate indicating each pixel position of the flat panel display to a value after the decimal point based on the density value at each coordinate position When,
Image processing means for forming subpixel coordinates composed of the same value after the decimal point at the coordinate position of the camera coordinates indicated by the FPD coordinates, and forming a neighborhood image density distribution for each subpixel coordinate; ,
Inspection image imaging means for displaying an inspection image on the flat panel display, capturing an image of the inspection image with the camera, and acquiring density values at inspection camera coordinates corresponding to the respective pixel positions in the camera; ,
Coordinate conversion means for converting the density value at the inspection camera coordinates into inspection corresponding coordinates corresponding to each pixel position of the flat panel display based on the correspondence table;
Estimated image forming means for forming an estimated image corresponding to the light emission luminance of the flat panel display from the density value at the corresponding coordinates for inspection and the neighborhood density distribution;
Point defect detection means for detecting point defects using the estimated image;
A flat panel display inspection apparatus comprising:

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