JP2009060460A - Device, method and program for calculating optical axis adjustment value, and computer-readable recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate an adjustment value for adjusting the optical axis of an imaging apparatus so as to capture such a photographed image of a display device for high-accuracy detection of pixels that the display device possesses, having a luminance that is different from that of surrounding pixels. <P>SOLUTION: An optical axis adjustment value calculation device comprises an imaging control section 2 for capturing a plurality of photographed images, obtained by imaging an optical axis adjustment pattern, in accordance with their imaging positions; a contrast calculation section 56 for calculating, in each of divided regions, artificial defective pixel contrast and proper article pixel contrast for each of the photographed images; a separation degree calculation section 57 for calculating, in each of the divided regions, the degree of pixel contrast separation for each of the photographed images; and a separation degree evaluation section 58, which calculates the optical axis adjustment value for adjusting relative positions of a lens unit and an imaging device, in such a way that a difference in the degree of separation for each of the divided region is settled within a prescribed range, on the basis of the relation of the degree of separation in each of the divided regions and the imaging position of a photographed image used for calculating the relevant degree of separation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical axis adjustment value calculation apparatus and an optical axis adjustment value calculation method for calculating an adjustment value for adjusting an optical axis of an imaging apparatus that captures an imaging target.

  An inspection method for inspecting an inspection object by analyzing an image obtained by imaging the inspection object is used for inspection of a display device such as a flat panel.

  When imaging a screen of a display device capable of gradation display, it is important to adjust the optical axis of the imaging device that captures the screen. This is because, when the optical axis is shifted, the sensitivity for detecting defects present on the screen becomes non-uniform in the screen, and the accuracy of defect detection decreases.

  Patent Document 1 discloses an example of a method for correcting a deviation of an optical axis, in other words, an example of a method for adjusting a relative position between an image of an imaging target and an imaging element. In the method described in Patent Document 1, the image pickup element with respect to the optical axis of the imaging optical system is based on imaging information obtained by imaging charts arranged at a plurality of positions in the optical axis direction (Z-axis direction) of the imaging optical system. Deviation is calculated.

  At this time, the position in the optical axis direction at which the contrast (image sharpness expressed based on the image standard deviation) of the chart image formed in each of the divided areas obtained by dividing the image sensor into three is maximized for each divided area. By detecting and matching the position where the contrast becomes maximum between the divided regions, the posture of the image sensor with respect to the imaging optical system around the Y axis (or around the X axis) is adjusted.

A method for matching the optical axes of a plurality of lenses incorporated in an imaging apparatus is disclosed in Patent Document 2. In the method described in Patent Document 2, a chart in which the same pattern is shown in the four corners is arranged in front of the camera, and the pattern shown in the four corners is imaged out of the video signal included in the video obtained by imaging the chart. The optical axis is adjusted so that the values obtained by integrating the high-frequency components of the video signals obtained from the four areas having the same area are substantially equal.
JP 2005-136743 A (published May 26, 2005) JP-A-6-350898 (published December 22, 1994)

  In the flat panel defect inspection, the contrast (brightness difference or brightness ratio) between the target pixel on the flat panel and the same color picture element located in the vicinity of the target pixel is calculated. Detect as prime.

  In this specification, the contrast of the picture element in the defect inspection is distinguished from general contrast and is referred to as picture element contrast. That is, the picture element contrast means a luminance difference or luminance ratio between two picture elements.

  In general, the threshold value is such that a picture element having no defect, in other words, a picture element having a luminance within a predetermined range (hereinafter referred to as a non-defective picture element) is detected as low as possible and a low-level defective picture element is detected. It is desirable to set a value that can be used.

  Therefore, the inventor of the present invention performs (1) picture element contrast between non-defective picture elements and picture elements between defective picture elements and non-defective picture elements when performing flat panel defect detection using a certain threshold. The degree of separation, which is a value indicating how far the contrast is away (hereinafter referred to as pixel contrast separation degree), and (2) a plurality of defective picture elements having the same luminance in the flat panel surface When present, it was considered preferable to perform imaging of the flat panel so that the picture element contrast separation degree regarding these defective picture elements becomes substantially the same.

  By using a captured image obtained by such imaging, it is possible to realize a highly accurate inspection with few false detections and maintaining the same inspection sensitivity in the flat panel surface.

  Conversely, if defect detection is performed using a captured image with small pixel contrast separation or non-uniform pixel contrast separation in a plurality of regions within the flat panel surface, false detection or non-detection increases. The inspection accuracy is likely to deteriorate.

  In such flat panel defect detection, as described above as the prior art, when the optical axis is adjusted using the general contrast (image sharpness) in the captured image obtained by imaging the chart pattern as an index, the flat panel Although the equivalence of image quality in different regions in the plane is guaranteed, since the pixel contrast separation degree is not always uniform, the defect detection sensitivity is not necessarily uniform.

  For example, even if the optical axis is adjusted on the basis that the difference in contrast (image sharpness) within the flat panel surface is within a few percent, the criterion is appropriate from the viewpoint of defect detection sensitivity. Cannot be said. That is, the standard does not guarantee that a defective picture element that is a detection target can be reliably detected at various points in the flat panel surface.

  Therefore, in the defect detection of a display device such as a flat panel, it is preferable to adjust the optical axis using an index value that reliably guarantees the defect detection sensitivity. In other words, it is preferable to adjust the optical axis appropriately from the viewpoint of defect detection sensitivity.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a display device that can detect a pixel having a luminance different from that of a surrounding pixel with high accuracy. An object of the present invention is to provide an optical axis adjustment value calculation device and an optical axis adjustment value calculation method for calculating an adjustment value for adjusting an optical axis of an imaging device so that a captured image can be acquired.

  In order to solve the above-described problem, an optical axis adjustment value calculation device according to the present invention is an imaging device in which an imaging device captures an image of a display device, which is an imaging target, formed on the surface of the imaging device by an optical element. An optical axis adjustment value calculation device that calculates an adjustment value for adjusting the position of the optical axis of the optical element by analyzing an image, and from a plurality of divided regions generated by dividing the screen of the display device An adjustment pattern including at least one first mark having the same brightness and a second mark having the same brightness different from the first mark, displayed in each of the selected at least two divided areas. A captured image acquisition unit configured to acquire a plurality of captured images captured by the imaging device while moving on a perpendicular line from the imaging device to the display device, in association with the imaging position; For each captured image acquired by the image image acquisition means, a first reference value indicating a difference between a luminance value of a pixel corresponding to the first mark and a luminance value of a pixel corresponding to the second mark, and the second mark The contrast value calculating means for calculating the second contrast value indicating the difference in the luminance values of the plurality of pixels corresponding to each divided region, and the contrast value calculating means for each captured image acquired by the captured image acquiring means. Separation degree calculating means for calculating a separation degree indicating how far the calculated first control value and the second control value are separated for each divided area, and separation for each divided area calculated by the separation degree calculating means. And the optical element so that the difference in the degree of separation for each divided region falls within a predetermined range based on the relationship between the degree of separation and the imaging position where the captured image used to calculate the degree of separation is captured. Relative to the image sensor Is characterized by comprising an optical axis adjustment value calculation means for calculating the optical axis adjustment value for adjusting the location.

  The optical axis adjustment value calculation method according to the present invention analyzes the picked-up image obtained by picking up an image of the display device, which is an object to be picked up, formed on the surface of the image pickup device by the optical element, thereby analyzing the optical An optical axis adjustment value calculation method in an optical axis adjustment value calculation device for calculating an adjustment value for adjusting the position of an optical axis of an element, which is selected from a plurality of divided regions generated by dividing a screen of a display device. An adjustment pattern including at least one first mark having the same brightness and a second mark having the same brightness different from the first mark, displayed on each of the at least two divided areas, A captured image acquisition step of acquiring a plurality of captured images captured by the imaging device while moving on a perpendicular line from the imaging device to the display device in association with the imaging position; For each captured image acquired in the image acquisition step, a first reference value indicating a difference between a luminance value of a pixel corresponding to the first mark and a luminance value of a pixel corresponding to the second mark, and the second mark For each divided region, and for each captured image acquired in the captured image acquisition step, the reference value calculation step A separation degree calculation step for calculating a separation degree indicating how far the first control value and the second reference value calculated in step S2 are separated for each division area, and each division area calculated in the separation degree calculation step. Based on the relationship between the degree of separation for and the imaging position where the captured image used to calculate the degree of separation is captured, the difference in the degree of separation for each divided region is within a predetermined range. It is characterized by comprising an optical axis adjustment value calculation step of calculating an optical axis adjustment value for adjusting the relative positions of the academic element and the imaging element.

  According to the above configuration, the captured image acquisition unit moves the adjustment pattern displayed on the screen of the display device that is the imaging target while moving on the perpendicular line from the imaging device to the display device (that is, the display device). The captured image captured by the imaging device is acquired in association with the imaging position.

  The adjustment pattern includes at least one first mark having the same luminance in each of at least two divided regions selected from a plurality of divided regions formed on the screen of the display device, and the first mark has a luminance Are displayed with different second marks.

  For each captured image acquired by the captured image acquisition unit, the contrast value calculation unit calculates a difference between the luminance value of the pixel corresponding to the first mark and the luminance value of the pixel corresponding to the second mark (for example, the luminance ratio or the luminance difference). ) And a second reference value indicating a difference in luminance values (for example, luminance ratio or luminance difference) of a plurality of pixels corresponding to the second mark is calculated for each divided region. In other words, the control value calculation means performs the process of calculating the first control value and the second control value for each of the captured images for each of at least two divided regions in the captured image.

  The separation degree calculation unit performs, for each captured image, a process of calculating a separation degree indicating how far the first control value and the second control value calculated by the control value calculation unit are separated for each divided region.

  Then, the optical axis adjustment value calculation means calculates the relationship between the separation degree for each divided region calculated by the separation degree calculation means and the imaging position associated with the captured image used for calculating the separation degree. Based on this, an optical axis adjustment value for adjusting the relative position between the optical element and the imaging element is calculated so that the difference in the degree of separation for each divided region falls within a predetermined range.

  Therefore, by using the difference in luminance value of the mark in the captured image obtained by imaging the mark having different luminance displayed on the screen of the display device as an index, the difference in the degree of separation for each divided region is within a predetermined range. The optical axis of the imaging device that images the display device can be adjusted so as to be within the range. Therefore, it is possible to acquire a captured image of the display device for detecting a picture element (that is, a defective picture element) having a luminance different from that of other picture elements included in the display apparatus with high accuracy.

  The optical axis adjustment value calculation device according to the present invention analyzes the captured image obtained by the imaging device taking an image of the display device, which is an imaging target, formed on the surface of the imaging device by the optical element, thereby obtaining the optical An optical axis adjustment value calculation device for calculating an adjustment value for adjusting the position of the optical axis of an element, wherein a display device in which an entire screen is lit with a first luminance is transferred from the imaging device to the display device. The plurality of first captured images captured by the image capturing apparatus while moving on the perpendicular line are acquired in association with the image capturing position, and the entire surface is acquired with a second brightness different from the first brightness. A captured image acquisition unit that acquires a plurality of second captured images captured by the imaging device in the same manner as the first captured image of the lit display device, and the captured image acquisition unit The acquired image pickup positions are the same. By combining the first and second captured images, at least two divided areas selected from a plurality of divided areas generated by dividing the screen of the display device have at least the first luminance. An image composition means for obtaining a composite image representing a state in which one first mark and the second mark having the second luminance are displayed, and the first mark for each composite image synthesized by the image composition means. A first contrast value indicating a difference between a luminance value of a pixel corresponding to the second mark and a luminance value of a pixel corresponding to the second mark, and a second contrast indicating a difference of luminance values of a plurality of pixels corresponding to the second mark. The distance between the first control value calculated by the control value calculating means and the second control value for each composite image synthesized by the image synthesizing means and the control value calculating means for calculating the value for each divided region Corresponding to the separation degree calculation means for calculating the separation degree for each divided area, the separation degree for each divided area calculated by the separation degree calculation means, and the composite image used to calculate the separation degree The optical axis adjustment value for adjusting the relative position between the optical element and the imaging element so that the difference in the degree of separation for each divided region falls within a predetermined range based on the relationship with the imaging position. An optical axis adjustment value calculation means for calculating is provided.

  The optical axis adjustment value calculation method according to the present invention analyzes the picked-up image obtained by picking up an image of the display device, which is an object to be picked up, formed on the surface of the image pickup device by the optical element, thereby analyzing the optical An optical axis adjustment value calculation method in an optical axis adjustment value calculation apparatus for calculating an adjustment value for adjusting the position of an optical axis of an element, the display device having the entire screen lit with a first luminance, A plurality of first captured images captured by the imaging device while moving on a perpendicular line from the imaging device to the display device are acquired in association with the imaging position, and the entire surface is defined as the first luminance. A captured image acquisition step of acquiring a plurality of second captured images captured by the imaging device in the same manner as the first captured image, in association with the captured positions, of the display device that is lit at a different second luminance; In the captured image acquisition process, Each of at least two divided regions selected from a plurality of divided regions generated by dividing the screen of the display device by combining the first and second captured images having the same imaging position acquired in the above In addition, an image composition step for obtaining a composite image representing a state in which at least one first mark having the first brightness and a second mark having the second brightness are displayed, and combining in the image composition step For each synthesized image, a first reference value indicating a difference between a luminance value of a pixel corresponding to the first mark and a luminance value of a pixel corresponding to the second mark, and a plurality of corresponding values corresponding to the second mark A reference value calculation step for calculating a second reference value indicating a difference in luminance value of pixels for each divided region, and a reference value calculation step for each composite image synthesized in the image synthesis step. A separation degree calculating step for calculating a separation degree indicating how far the calculated first control value and the second control value are separated for each divided area, and each divided area calculated in the separation degree calculation step. Based on the relationship between the degree of separation for and the imaging position corresponding to the composite image used to calculate the degree of separation, the difference of the degree of separation for each divided region falls within a predetermined range. And an optical axis adjustment value calculating step of calculating an optical axis adjustment value for adjusting a relative position between the optical element and the imaging element.

  According to the above configuration, the captured image acquisition unit moves the display device in which the entire screen of the display device is lit at the first luminance while moving on the perpendicular line from the imaging device to the display device. A plurality of first captured images captured by the device are acquired in association with the imaging positions, and a display device in which the entire screen of the display device is lit with the second luminance is captured in the same manner as the first captured image. The plurality of second captured images obtained are acquired in association with the imaging positions.

  The image synthesizing unit is selected from a plurality of divided regions generated by dividing the screen of the display device by synthesizing the first and second captured images acquired by the captured image acquiring unit and having the same imaging position. A composite image representing a state in which at least one first mark having a first luminance and a second mark having a second luminance are displayed in each of at least two divided regions is generated.

  The control value calculation means calculates the first control value and the second control value for each divided region for each composite image synthesized by the image composition means. The degree-of-separation calculating unit calculates the degree of separation for each divided region indicating how far the first control value and the second control value are separated for each composite image synthesized by the image synthesis unit.

  Then, the optical axis adjustment value calculation means calculates the degree of separation for each divided region based on the relationship between the degree of separation for each divided region and the imaging position corresponding to the composite image used to calculate the degree of separation. An optical axis adjustment value for adjusting the relative position between the optical element and the imaging element is calculated so that the difference between the values falls within a predetermined range.

  Therefore, the display device is imaged so that the difference in the degree of separation for each divided region falls within a predetermined range by using the difference in luminance value between the first and second marks included in the composite image as an index. The optical axis of the imaging device can be adjusted. Therefore, it is possible to acquire a captured image of the display device for detecting a defective pixel element having a luminance different from that of other picture elements with high accuracy.

  In addition, the optical axis adjustment value calculation means obtains the maximum degree of separation for each divided area from the set of degrees of separation calculated for the specific divided area for each divided area, and then calculates the maximum degree of separation. It is preferable to compare the imaging positions that have been obtained between the divided regions and calculate the optical axis adjustment value based on the comparison result.

  According to the above configuration, the optical axis adjustment value calculating unit obtains the imaging position with the maximum degree of separation for each divided region, compares the imaging position between the divided regions, and based on the comparison result, the imaging device An adjustment value for adjusting the optical axis is calculated.

  Therefore, an adjustment value for adjusting the optical axis of the imaging apparatus can be calculated using the relationship between the maximum degree of separation and the imaging position as an index.

  Further, it is preferable that the first mark is an artificial defect picture element having a luminance outside a predetermined range, and the second mark is a non-defective picture element having a luminance within a predetermined range.

  With the above configuration, the difference between the luminance values of the artificial defect picture element and the non-defective picture element in the picked-up image obtained by picking up the artificial defect picture element and the non-defective picture element displayed on the screen of the display device or the composite image corresponding to the picked-up image. By using as an index, the optical axis of the imaging device that images the display device can be adjusted, and a captured image of the display device for detecting a defective pixel included in the display device with high accuracy can be acquired.

  The image processing apparatus further includes posture adjustment value calculation means for calculating a posture adjustment value for adjusting a relative position between the display device and the imaging device by analyzing a captured image obtained by capturing an image of the display device. preferable.

  According to the above configuration, the posture adjustment value calculating unit calculates the posture adjustment value by analyzing a captured image obtained by capturing an image of the display device.

  Therefore, the relative position between the imaging object and the imaging device can be adjusted, and the adjustment of the optical axis by the optical axis adjustment value can be performed efficiently.

  An optical axis adjustment value calculation program for operating the optical axis adjustment value calculation apparatus, an optical axis adjustment value calculation program for causing a computer to function as each of the means, and a computer on which the optical axis adjustment value calculation program is recorded A readable recording medium is also included in the technical scope of the present invention.

  As described above, the optical axis adjustment value calculation device according to the present invention is identical to each other displayed in each of at least two divided regions selected from a plurality of divided regions generated by dividing the screen of the display device. The adjustment pattern including at least one first mark having luminance and a second mark having the same luminance different from the first mark is moved while moving on a perpendicular line from the imaging device to the display device. A captured image acquisition unit that acquires a plurality of captured images captured by the imaging device in association with the imaging position, and a luminance value of a pixel corresponding to the first mark for each captured image acquired by the captured image acquisition unit And a first contrast value indicating a difference between the luminance values of the pixels corresponding to the second mark and a second contrast value indicating a difference of the luminance values of the plurality of pixels corresponding to the second mark. The degree of separation indicating how far the first control value and the second control value calculated by the control value calculating means are separated for each captured image acquired by the control value calculating means and the captured image acquiring means For each divided region, a separation degree for each divided region calculated by the separation degree calculating unit, and an imaging position where the captured image used for calculating the separation degree is captured. An optical axis for calculating an optical axis adjustment value for adjusting the relative position between the image of the display device and the imaging element so that the difference in the degree of separation for each divided region falls within a predetermined range based on the relationship And an adjustment value calculation means.

  The optical axis adjustment value calculation method according to the present invention includes at least one having the same luminance displayed in each of at least two divided areas selected from a plurality of divided areas generated by dividing the screen of the display device. The image pickup apparatus picked up an adjustment pattern including two first marks and a second mark having the same brightness different from the first mark while moving on the perpendicular line from the image pickup apparatus to the display device. A captured image acquisition step of acquiring a plurality of captured images in association with the imaging position, and a luminance value of the pixel corresponding to the first mark and the second value for each captured image acquired in the captured image acquisition step. A first contrast value indicating a difference between the luminance values of the pixels corresponding to the mark and a second contrast value indicating a difference of the luminance values of the plurality of pixels corresponding to the second mark are assigned to each divided region. Separation indicating how far the first control value and the second control value calculated in the control value calculation step are separated for each of the control value calculation step to be calculated and the captured image acquired in the captured image acquisition step A separation degree calculating step for calculating the degree of each divided region; a separation degree for each divided region calculated in the separation degree calculating step; and an imaging position where the captured image used for calculating the separation degree is captured. Based on the relationship, the optical axis adjustment value for adjusting the relative position between the image of the display device and the image sensor is calculated so that the difference in the degree of separation for each divided region falls within a predetermined range. And an optical axis adjustment value calculation step.

  The optical axis adjustment value calculation apparatus according to the present invention captures an image captured by the imaging apparatus while moving on a perpendicular line from the imaging apparatus to the display apparatus with the entire screen illuminated at the first luminance. A plurality of first captured images are acquired in association with the imaging positions, and a display device in which the entire surface is lit with a second luminance different from the first luminance is used by the imaging device. A captured image acquisition unit that acquires a plurality of second captured images captured in the same manner as an image in association with the imaging position, and a first and second imaging with the same imaging position acquired by the captured image acquisition unit At least one first mark having the first brightness and each of at least two divided areas selected from a plurality of divided areas generated by dividing the screen of the display device by combining the images; An image composition means for obtaining a composite image representing a state in which the second mark having the second brightness is displayed, and the brightness of the pixel corresponding to the first mark for each composite image synthesized by the image composition means A first contrast value indicating a difference between a value and a brightness value of a pixel corresponding to the second mark, and a second contrast value indicating a difference between brightness values of a plurality of pixels corresponding to the second mark. The degree of separation indicating how far the first control value and the second control value calculated by the control value calculating means are separated for each composite image synthesized by the control value calculating means and the image synthesizing means. Relationship between the degree-of-separation calculating means calculated for each divided area, the degree of separation for each divided area calculated by the above-mentioned degree of separation calculating means, and the imaging position corresponding to the composite image used for calculating the degree of separation Based on each division And an optical axis adjustment value calculating means for calculating an optical axis adjustment value for adjusting the relative position between the image of the display device and the image sensor so that the difference in separation degree is within a predetermined range. It is.

  The optical axis adjustment value calculation method according to the present invention is such that the display device in which the entire screen of the display device is lit with the first luminance moves on the vertical line extending from the imaging device to the display device. A plurality of first captured images captured by the camera are acquired in association with their imaging positions, and the imaging device is a display device in which the entire surface is lit at a second luminance different from the first luminance. A captured image acquisition step of acquiring a plurality of second captured images captured in the same manner as the first captured image in association with the captured position, and the first captured image acquired in the captured image acquisition step and having the same imaging position. And at least two divided regions selected from a plurality of divided regions generated by dividing the screen of the display device by combining the second captured image and at least the first luminance. An image composition step for obtaining a composite image representing a state in which two first marks and the second mark having the second luminance are displayed, and the first mark for each composite image synthesized in the image composition step A first contrast value indicating a difference between a luminance value of a pixel corresponding to the second mark and a luminance value of a pixel corresponding to the second mark, and a second contrast indicating a difference of luminance values of a plurality of pixels corresponding to the second mark. A reference value calculation step for calculating a value for each divided region, and for each synthesized image synthesized in the image synthesis step, how much is the first control value and the second control value calculated in the control value calculation step Separation degree calculation step for calculating the degree of separation for each divided region, separation degree for each divided region calculated in the separation degree calculation step, and composition used for calculating the separation degree Light for adjusting the relative position between the image on the display device and the imaging element so that the difference in the degree of separation for each divided region falls within a predetermined range based on the relationship with the imaging position corresponding to the image. And an optical axis adjustment value calculating step for calculating an axis adjustment value.

  Therefore, there is an effect that it is possible to acquire a captured image of the display device that can detect with high accuracy a picture element having brightness different from that of the surrounding picture elements.

[Embodiment 1]
One embodiment of the present invention will be described below with reference to FIGS.

(Configuration of automatic inspection system 30)
FIG. 2 is a schematic diagram showing the configuration of the automatic inspection system 30 of the present embodiment, and FIG. 3 is a schematic diagram showing the configuration of the automatic inspection system 30 in more detail. In the following description, as an example of the inspection target of the automatic inspection system 30, a flat panel 40 in which the same color picture elements of R, G, B are repeatedly arranged in the order of R, G, B will be described. The inspection target is not limited to a flat panel, and may be any display device capable of displaying a later-described adjustment pattern and capable of gradation display. In FIG. 3, the flow of data is indicated by solid arrows, and the direction of control is indicated by broken arrows.

  In recent years, flat panels represented by liquid crystal panels have been greatly increased in size, and in an automatic defect inspection apparatus that inspects defects in flat panels, the angle of view and the imaging distance of the imaging apparatus are increasing. Therefore, if the relative orientation (relative position and relative angle) between the flat panel and the imaging device (specifically, the imaging device and the lens) is slightly shifted, the position of the image formed on the imaging surface of the imaging device changes greatly. there's a possibility that.

  In this way, the optical axis is adjusted based on the contrast (image sharpness) of the image obtained by imaging the flat panel displaying the chart pattern as in the above-described conventional technique in a state in which the relative orientation between the flat panel and the imaging device is shifted. Even so, it is difficult to perform appropriate optical axis adjustment. For this reason, it is preferable to further adjust a minute shift between the imaging element and the lens after adjusting the relative posture between the flat panel and the imaging device.

  Based on such a technical idea, as shown in FIGS. 2 and 3, the automatic inspection system 30 is an imaging system that adjusts the relative posture of the camera (imaging device) 11 with respect to the flat panel and the position of the lens with respect to the imaging device. 10 and a control device 1.

  Strictly speaking, the adjustment of the attitude of the imaging device with respect to the flat panel is also included in the adjustment of the optical axis. Hereinafter, the attitude adjustment of the imaging device with respect to the flat panel is referred to as a rough adjustment of the optical axis, and the adjustment of the lens position with respect to the imaging element is referred to as a fine adjustment of the optical axis.

  More specifically, the automatic inspection system 30 detects the defective picture element of the flat panel 40 by imaging the flat panel 40 and analyzing the captured image, and the control device (optical axis adjustment value). (Calculation device) 1, imaging system 10, inspection device 31, and pattern generation device 32.

  The imaging system 10 images the flat panel 40, and includes a camera 11 and a camera stage 15 as shown in FIG.

  The camera 11 is a digital camera such as a CCD (Charge Coupled Devices) camera, and includes a lens unit (optical element) 12, an image sensor 14, and a support jig 13 that adjusts the relative angle of the lens unit 12 with respect to the image sensor 14. Yes. The camera used in the imaging system 10 may be any camera that can adjust the angle around the X axis of the lens with respect to the imaging element, and any mechanism that adjusts the angle of the lens may be used.

  The camera stage 15 has a direction perpendicular to the flat panel 40 (Z-axis direction in FIG. 2), a direction parallel to one side of the flat panel 40 (X-axis direction in FIG. 2), and the flat panel 40. Is provided with a mechanism for adjusting the posture of the camera 11 and the distance between the flat panel 40 and the camera 11 around three direction axes in a direction parallel to the other side (Y-axis direction in FIG. 2). That is, the camera stage 15 is an imaging posture adjustment device that adjusts the position and angle of the camera 11 around the X axis, the Y axis, and the Z axis with respect to the flat panel 40.

  Specifically, the camera stage 15 includes a camera support unit 16 and a main body 17 that support the camera 11 and whose posture can be adjusted, and can move on a rail 18 that extends in the Z-axis direction. .

  The pattern generating device 32 outputs a control signal for applying a predetermined display pattern to the flat panel 40 in accordance with a command from the pattern control unit 7 described later.

  The control device 1 analyzes the picked-up image obtained by picking up the image of the flat panel 40 imaged on the surface of the image pickup element by the lens unit 12 to adjust the position of the optical axis of the lens unit 12. The imaging control unit (captured image acquisition means) 2, the camera position adjustment unit 3, the image memory 4, the image processing unit (optical axis adjustment value calculation device) 5, the controller 6, the pattern control unit 7 and the input Part 8 is provided.

  The imaging control unit 2 controls the camera 11. Specifically, the imaging control unit 2 controls the timing of imaging by the camera 11, adjusts the focus, adjusts the optical axis (adjustment of the support jig 13), and captures images by the camera 11. Captured images are acquired. More specifically, the imaging control unit 2 captures a plurality of captured images captured by the camera 11 while moving a later-described optical axis adjustment pattern on a vertical line from the camera 11 to the flat panel 40. Acquired in association with. Information on the imaging position may be output from the camera stage 15 or may be output from the camera position adjustment unit 3.

  The imaging control unit 2 includes a focus adjustment unit 21 that performs focus adjustment of the camera 11 and a lens position adjustment unit 22 that adjusts the optical axis of the lens unit 12 by controlling the support jig 13.

  The camera position adjustment unit 3 adjusts the distance between the camera 11 and the flat panel 40 by controlling the camera stage 15.

  The image memory 4 is a storage unit that stores a captured image acquired by the imaging control unit 2.

  The image processing unit 5 calculates the adjustment value for adjusting the optical axis of the camera 11 by analyzing the captured image acquired by the imaging control unit 2. Details of the image processing unit 5 will be described later.

  The pattern controller 7 applies a predetermined display pattern to the flat panel 40 by controlling the pattern generator 32.

  The input unit 8 receives an instruction from the user, and is, for example, a keyboard or a touch panel.

  The controller 6 controls each functional block of the control device 1.

  Note that the present invention can also be realized as an imaging system that acquires the captured image of the display device by removing the inspection apparatus 31 from the automatic inspection system 30. Further, the camera position adjustment unit 3 may be incorporated in the imaging control unit 2.

(Configuration of marker of flat panel 40)
FIG. 4 is a conceptual diagram showing markers for coarse adjustment of the optical axis displayed on the flat panel 40. When coarse adjustment of the optical axis of the camera 11 is performed, as shown in FIG. 4, markers A and B for coarse adjustment of the optical axis are displayed on the flat panel 40.

  The marker A is a straight line parallel to the Y axis, and is a straight line connecting the intermediate points (points 41a and 42a) between two sides (sides 41 and 42) parallel to the X axis of the flat panel 40.

  The marker B is a straight line parallel to the X axis, and is a straight line connecting the intermediate points (points 43a and 44a) between two sides (sides 43 and 44) parallel to the Y axis of the flat panel 40.

  Such markers A and B are displayed on the flat panel 40 by signals output from the pattern generator 32. Note that the markers A and B may be realized by a linear object, and the linear object may be attached to the flat panel 40.

(Configuration of optical axis adjustment pattern)
FIG. 5 is a diagram illustrating an example of an optical axis adjustment pattern. In the example shown in FIGS. 5A to 5D, the inspection target area of the flat panel 40 is the entire screen of the flat panel 40. In the example shown in FIG. 5A, the screen of the flat panel 40 is equally divided into three in the vertical direction (Y-axis direction). In the example shown in FIG. Direction), and in the example shown in FIGS. 5C and 5D, it is divided into 9 parts in the vertical and horizontal directions. In other words, in the example shown in FIGS. 5C and 5D, the inspection target region is divided into nine in a matrix.

  Such a divided inspection target area of the flat panel 40 is referred to as a divided area. Further, each of the divided areas divided into three in the vertical direction is referred to as an upper divided area, a central divided area, and a lower divided area in order from the largest Y coordinate. The areas of the divided regions are preferably the same as each other, but are not necessarily the same.

  Further, in the example shown in FIGS. 5A and 5B, R (red), G (green), and B (blue) artificial defect picture elements having the same brightness in each of the three divided regions. Three pairs of (first mark) are lit, and the other picture elements are lit as non-defective picture elements (second mark). Such a display pattern composed of a set of artificial defect picture elements and non-defective picture elements displayed in the divided area is referred to as an optical axis adjustment pattern (adjustment pattern).

  Further, in the example shown in FIG. 5C, one set of R, G, and B artificial defect picture elements having the same brightness in five divided areas among nine divided areas. The other picture elements are lit as good picture elements.

  In the example shown in FIG. 5 (d), one set of R, G, and B artificial defect picture elements having the same brightness is lit in each of the nine divided areas. The other picture elements are lit as good picture elements.

  That is, the pattern control unit 7 includes at least one artificial defect pixel having the same luminance in each of at least two regions selected from a plurality of regions generated by dividing the inspection target region of the flat panel 40; A plurality of non-defective picture elements having the same luminance and located around the artificial defect picture element are turned on.

  The artificial defect picture element is a picture element having a luminance outside a predetermined range (reference threshold), and is a picture element imitating a defect picture element generated in a manufacturing process. A picture element having a luminance within a predetermined range is referred to as a non-defective picture element. Actually, it is determined whether or not the picture element is a defective picture element by comparing the picture element with the same color picture element located around a certain picture element.

  The brightness of the artificial defect picture element may be higher or lower than a predetermined range determined as a non-defective picture element. In other words, the artificial defect picture element may be a bright spot defect picture element or a black spot defect picture element.

  Further, the brightness of the artificial defect picture element to be lit is the same for at least the artificial defect picture elements of the same color. For example, the luminances of R-type artificial defect picture elements are all the same. Further, only one type of artificial defect picture element among R, G, and B may be displayed as the optical axis adjustment pattern.

  Further, when displaying the optical axis adjustment pattern in three of the plurality of divided areas, it is preferable to display the optical axis adjustment pattern evenly on the entire screen, and at least the optical axis adjustment pattern is displayed. It is preferable that the entire screen has a line-symmetric axis.

  Further, the number of non-defective picture elements as the second mark may be one, but it is desirable to be a plurality.

  In the following description, in order to simplify the description, the panel is divided into three in the vertical direction, and one set of artificial defect picture elements (for example, black spot defects in a white lighting state) having the same luminance value in each region. An explanation will be given based on an example in which each lamp is lit.

(Configuration of the image processing unit 5)
FIG. 1 is a functional block diagram showing the configuration of the image processing unit 5. As shown in FIG. 1, the image processing unit 5 includes an optical axis rough adjustment unit (attitude adjustment value calculation means) 51 and an optical axis fine adjustment unit (optical axis adjustment value calculation device) 55.

  The optical axis coarse adjustment unit 51 calculates a posture adjustment value for adjusting a relative position (relative posture) between the flat panel 40 and the camera 11 by analyzing a captured image of the flat panel 40. An axis angle adjusting unit 52, a Y axis angle adjusting unit 53, and an X axis angle adjusting unit 54 are provided.

  The Z-axis angle adjustment unit 52 calculates an adjustment value for adjusting the posture of the camera 11 around the Z-axis, and the Y-axis angle adjustment unit 53 adjusts an adjustment value for adjusting the posture of the camera 11 around the Y-axis. The X-axis angle adjustment unit 54 calculates an adjustment value for adjusting the posture of the camera 11 around the X-axis. A method of calculating the attitude adjustment value in these angle adjustment units will be described later.

  The optical axis fine adjustment unit 55 calculates an adjustment value for fine adjustment of the optical axis of the camera 11, and includes a contrast calculation unit (control value calculation unit) 56 and a separation degree calculation unit (separation degree calculation unit). 57 and a degree-of-separation evaluation unit (optical axis adjustment value calculation means) 58. Details of the contrast calculation unit 56 and the separation degree calculation unit 57 will be described later.

  Based on the relationship between the degree of separation for each divided region calculated by the degree-of-separation calculation unit 57 and the imaging position where the captured image used for calculating the degree of separation is captured, The optical axis adjustment value for adjusting the relative position between the lens unit 12 and the image sensor 14 is calculated so that the difference in the degree of separation for the divided areas is within a predetermined range.

(Picture Element Contrast Calculation Method in Contrast Calculation Unit 56)
FIG. 6 is a diagram for explaining an example of a method for calculating a picture element contrast and a picture element contrast separation degree. In the figure, the screen of the flat panel 40 is divided into three in the vertical direction, and the upper divided area in the image obtained by imaging the flat panel 40 in which six sets of artificial defect picture elements are displayed in each of the three divided areas. A method for calculating the pixel contrast and the pixel contrast separation degree is shown. Further, “n” described in FIG. 6 indicates the number of all picture elements (that is, non-defective picture elements) other than the artificial defect picture element (a set of R, G, and B) in the upper divided area. ing.

  For each captured image acquired by the imaging control unit 2, the contrast calculation unit 56 determines the luminance value of the pixel corresponding to the artificial defect pixel (first mark) and the luminance value of the pixel corresponding to the non-defective pixel (second mark). Each of an artificial defect pixel contrast (first control value) indicating a difference between the pixel and a non-defective pixel contrast (second control value) indicating a difference in luminance values of a plurality of pixels corresponding to the plurality of non-defective pixels Calculate for the region.

  For example, the contrast calculation unit 56 includes an artificial defect pixel (see (6 in FIG. 6) among a plurality of pixels constituting a captured image captured by the camera 11 having the image sensor 14 in which a plurality of image sensors are arranged in a matrix. the luminance value output from the imaging device that has imaged the pixel of interest 45a in a) and the same Y coordinate as that of the artificial defect pixel, and located at the closest position to the artificial defect pixel; Difference between the average value of the luminance values output from the imaging elements that respectively image two good quality picture elements having the same color as the artificial defect picture element (corresponding to the peripheral picture elements 45b and 45c in FIG. 6A) The absolute value of is calculated. The absolute value of this difference is the artificial defect pixel contrast (first control value).

  Information indicating which pixel corresponds to the artificial defect picture element among the pixels constituting the picked-up image obtained by picking up the flat panel 40 (in other words, which image pickup element among the plurality of image pickup elements of the camera 11) (Information indicating whether or not an image of an artificial defect picture element) is stored in advance in a memory (for example, the image memory 4) that can be used by the contrast calculation unit 56.

  Similarly, the contrast calculation unit 56 is output from an image pickup device that has picked up a non-defective picture element (corresponding to the target picture element 45a in FIG. 6A) among the pixels constituting the picked-up image picked up by the camera 11. The two non-defective picture elements having the same brightness as the non-defective picture element and having the same Y coordinate as the non-defective picture element and having the same color as the non-defective picture element (in FIG. 6A) The absolute value of the difference between the average value of the luminance values output from the image sensors that respectively image the peripheral picture elements 45b and 45c) is calculated. The absolute value of this difference is the non-defective pixel contrast (second control value).

  Information indicating which pixel corresponds to a non-defective picture element among pixels constituting a captured image obtained by imaging the flat panel 40 (in other words, which image sensor out of a plurality of image sensors included in the camera 11). (Information indicating whether or not a non-defective picture element is captured) is stored in advance in a memory that can be used by the contrast calculation unit 56.

  The contrast calculation unit 56 calculates the artificial defect pixel contrast and the non-defective pixel contrast for each divided area in the captured image obtained by imaging the divided area of the flat panel 40. When there are a plurality of artificial defect picture elements in one divided area, a plurality of artificial defect picture element contrast statistical values (for example, average value, intermediate value, maximum value) calculated from each artificial defect picture element (Or the minimum value) may be used as the artificial defect pixel contrast.

  In addition, as the non-defective picture element contrast, a statistical value (for example, an average value, a representative value, an intermediate value) of the good picture element contrast calculated with respect to all (or a part) non-defective picture elements in the divided region to which the noticeable artificial defect picture element belongs. Value, maximum value, or minimum value), or the standard deviation of luminance values of all (or a part of) non-defective pixels in the divided area to which the artificial defect pixel of interest belongs (that is, variations in luminance values). Or 6 times the standard deviation may be obtained.

  Note that the picture element contrast calculation method in the contrast calculation unit 56 is not limited to the above. For example, as the artificial defect picture element contrast, the luminance value output from the image pickup element that has picked up the artificial defect picture element and one good picture element of the same color as the artificial defect picture element located in the vicinity of the defective picture element The absolute value of the difference value from the brightness value output from the imaged image sensor may be obtained, or the brightness value output from the image sensor imaged of the artificial defect picture element and the position near the artificial defect picture element The ratio of the luminance value output from the imaging element that images one good picture element of the same color as the artificial defect picture element may be obtained. As described above, the picture element contrast basically means a difference or ratio between luminance values respectively output from the image pickup elements that picked up two picture elements.

  The peripheral picture element (background picture element) for the target picture element may be a picture element located in the vicinity of the target picture element in the same color picture element array to which the target picture element belongs. That is, in FIG. 6A, a picture element positioned in the vertical direction of the target picture element 45a may be used as a peripheral picture element. In this case, the same-colored picture element (picture element 45d) that is second closest to the noticeable picture element 45a may be used as the peripheral picture element. In other words, the picture element located in the vicinity of the target picture element is the same color picture element having a predetermined positional relationship with the target picture element, and may be the same color picture element closest to the target picture element. It may be the same or second closest color element.

  Further, the contrast between the target picture element 45a and a plurality of picture elements (for example, eight picture elements 45b to 45i in FIG. 6A) positioned so as to surround the target picture element 45a. And calculating a statistical value such as an average value, a representative value, an intermediate value, a maximum value or a minimum value of a plurality of obtained contrasts (eight contrasts in the above example), and calculating the statistical values as defect pictures. It may be used as an elementary contrast.

  Further, the contrast value calculation method in the contrast calculation unit 56 is preferably the same as the contrast calculation method for detecting defective picture elements in the inspection apparatus 31.

(Calculation method of pixel contrast separation degree in the separation degree calculation unit 57)
The degree-of-separation calculating unit 57 calculates a degree of defect separation indicating how far the artificial defect pixel contrast and the non-defective pixel contrast are separated for each captured image acquired by the imaging control unit 2. Specifically, the degree-of-separation calculation unit 57 calculates the absolute value of the difference between the artificial defect pixel contrast (or its statistical value) calculated by the contrast calculation unit 56 and the non-defective pixel contrast (or its statistical value) or The ratio is calculated as the pixel contrast separation degree.

(Procedure for coarse adjustment of optical axis)
Next, an example of the procedure for coarse adjustment of the optical axis will be described with reference to FIG. FIG. 7 is a flowchart illustrating an example of a procedure for coarse adjustment of the optical axis. Note that each functional block of the control device 1 basically operates under the control of the controller 6, but in order to simplify the explanation, an expression as if each functional block is operating spontaneously is used. There is a place.

  First, the controller 6 controls the camera stage 15 via the camera position adjustment unit 3 to move the camera 11 to the origin, that is, the initial setting position (design data position) (S1). The position of this design data is a position where a captured image for defect inspection determined by design is captured.

  Thereafter, the pattern control unit 7 controls the pattern generator 32 to display the marker A and the marker B on the flat panel 40 as shown in FIG. 4 (S2) (see FIG. 7A). .

  Thereafter, the imaging control unit 2 controls the camera 11 to acquire a captured image (first captured image) of the flat panel 40 displaying the marker A and the marker B, and stores the first captured image in the image memory 4. Store (S3).

  The Z-axis angle adjustment unit 52 of the optical axis rough adjustment unit 51 adjusts the angle around the Z-axis of the camera 11 by analyzing the position of the marker A included in the first captured image stored in the image memory 4. .

  Specifically, the Z-axis angle adjustment unit 52 is configured so that the X coordinate of one end (upper end) of the marker A in the first captured image matches the X coordinate of the other end (lower end). An adjustment value for adjusting the angle around the Z axis of the camera 11 is calculated and output to the camera position adjustment unit 3.

  FIG. 8 is a diagram illustrating an angle adjustment method of the camera 11. In (a) of the figure, an adjustment value (angle α) for adjusting the angle around the Z axis is calculated from the X coordinate of the upper end of the marker A and the length of the side in the Y axis direction of the first captured image. How to do is shown.

  The camera position adjusting unit 3 adjusts the angle around the Z axis of the camera 11 by controlling the camera support unit 16 of the camera stage 15 based on the adjustment value calculated by the Z axis angle adjusting unit 52 (S4). (See FIG. 7B).

  In consideration of the following procedure, it is desirable to adjust the upper end and the lower end of the marker A so as to pass through the center of the first captured image. For this purpose, the Z-axis angle adjustment unit 52 corresponds to the X-axis side edges of the first captured image in which the X coordinates of the upper and lower ends of the marker A in the first captured image correspond to the points 41a and 42a in FIG. The camera position adjustment unit 3 translates the camera 11 in the X-axis direction based on the adjustment value.

  Further, the angle around the Z axis of the camera 11 may be adjusted using the marker B.

  Subsequently, when the point away from the origin by D1 [mm] in the positive direction of the Z axis is set as the point A and the point away from the origin by D2 [mm] in the negative direction of the Z axis is set as the point B, the camera position adjusting unit 3 The camera 11 is moved from the point A to the point B by controlling the stage 15. At that time, the imaging control unit 2 causes the camera 11 to image the flat panel 40 displaying the marker A at the point A and the point B, and associates the image with the imaging position (the point A or the point B). The captured image and the third captured image) are stored in the image memory 4 (S5).

  The Y-axis angle adjustment unit 53 is configured such that the X coordinates of the upper end and the lower end of the marker A are the X axes of the second and third captured images in the second captured image and the third captured image captured at the points A and B, respectively. An adjustment value for adjusting the angle around the Y axis of the camera 11 is calculated so as to coincide with the X coordinate of the intermediate point of the direction side. The Y-axis angle adjustment unit 53 outputs the calculated adjustment value to the camera position adjustment unit 3.

In FIG. 8B, an adjustment value (angle α) for adjusting the angle around the Y axis, the distance (L ₁ −L ₂ ) between the point A and the point B, and the upper end of the marker A are shown. A method of calculating from the difference between the X coordinate of X and the X coordinate of the intermediate point of the side in the X-axis direction of the first captured image is shown.

  The camera position adjustment unit 3 adjusts the angle around the Y axis of the camera 11 by controlling the camera support unit 16 of the camera stage 15 based on the adjustment value calculated by the Y axis angle adjustment unit 53 (S6). (See (c) of FIG. 7).

  Subsequently, the camera position adjustment unit 3 moves the camera 11 from the point A to the point B by controlling the camera stage 15. At that time, the imaging control unit 2 causes the camera 11 to image the flat panel 40 on which the marker B is displayed at the points A and B, and associates these images with the imaging positions (the fourth captured image and the fifth captured image). ) Is stored in the image memory 4 (S7).

  The X-axis angle adjustment unit 54 determines that the Y coordinates of the upper end and the lower end of the marker B are the Y axes of the fourth and fifth captured images in the fourth captured image and the fifth captured image captured at the points A and B, respectively. An adjustment value for adjusting the angle around the X axis of the camera 11 is calculated so as to coincide with the Y coordinate of the intermediate point of the direction side (points corresponding to the points 43a and 44a in FIG. 4). The X-axis angle adjustment unit 54 outputs the calculated adjustment value to the camera position adjustment unit 3.

  The adjustment value for adjusting the angle around the X axis of the camera 11 can be calculated by the same method as the angle adjusting method around the Y axis shown in FIG.

  The camera position adjusting unit 3 adjusts the angle around the X axis of the camera 11 by controlling the camera support unit 16 of the camera stage 15 based on the adjustment value calculated by the X axis angle adjusting unit 54 (S8). (See (d) of FIG. 7).

  Note that in the fourth and fifth captured images, in order for the Y coordinates of the upper end and the lower end of the marker B to coincide with the Y coordinates of the midpoint of the sides in the Y-axis direction of the fourth and fifth captured images, the camera 11 May need to be translated in the Y-axis direction.

  By following the above procedure, the relative postures of the camera 11 with respect to the flat panel 40 around the X axis, Y axis, and Z axis are temporarily determined. In this state, the positions at which the markers A and B are projected onto the intermediate points of the X and Y coordinates of the captured image are set as new origins (S9). The difference between the initial origin and the new origin corresponds to the distance moved in parallel when the angles around the X and Y axes are adjusted.

  The values of D1 and D2 are values determined by the specification and measurement conditions of the imaging system 10 such as “what is the degree of adjustment tolerance of the angle around the X axis or Y axis of the camera”.

In FIG. 8B, the adjustment angle α [deg] is the distance (L ₁ −L ₂₎ between the displacement amount D [mm] of the marker A from the center of the captured image and the point A and the point B. ). If the minimum measurement resolution of the displacement amount D is 0.5 [mm], and the allowable amount of the adjustment angle α is 0.1 [deg] (tan α = 0.0017), D = (L ₁ − Due to the relationship of L ₂ ) tanα, the value of (L ₁ −L ₂ ) is required to be at least about 294 [mm]. That is, when D1 = D2, D1 = D2 = 147 [mm].

  Further, the values of D1 and D2 may be different when the camera 11 is adjusted around the X axis, when adjusted around the Y axis, and when the optical axis is finely adjusted. For example, at the time of fine adjustment of the optical axis, the peak width of the curve indicating the pixel contrast separation degree and the width of the skirt of the curve are examined in advance from preliminary experiments, and the values of D1 and D2 are determined based on them. Good.

  The procedure for the rough adjustment of the optical axis described above is merely an example, and any method may be adopted as long as the optical axis adjustment method can perform the rough adjustment of the optical axis.

(Procedure for fine adjustment of the optical axis)
Next, an example of the procedure for fine adjustment of the optical axis will be described with reference to FIG. FIG. 9 is a flowchart illustrating an example of a procedure for fine adjustment of the optical axis.

  First, the pattern control unit 7 controls the pattern generator 32 to display the optical axis adjustment pattern on the flat panel 40 (S11). Here, the pattern for optical axis adjustment shown in FIG. 5A (the imaging target area is equally divided into three upper and lower parts, and the pattern of the artificial defect picture element is displayed in each of the divided areas) is displayed. (See FIG. 9A).

  Then, the focus adjustment unit 21 of the imaging control unit 2 adjusts the focus of the camera 11 with the origin near the center of the captured image (S12). Thereafter, the focus state is fixed.

  Subsequently, the camera position adjustment unit 3 moves the camera 11 from the point A to the point B by controlling the camera stage 15. At this time, the imaging control unit 2 causes the camera 11 to image the flat panel 40 at a predetermined interval while the camera 11 moves from the point A to the point B, and associates it with the imaging position of the camera 11 on the Z axis. The captured image is stored in the image memory 4 (S13) (see FIG. 9B) (captured image acquisition step).

  The contrast calculation unit 56 of the optical axis fine adjustment unit 55 is provided for each of a plurality of captured images stored in the image memory 4 for each captured image region obtained by capturing three divided regions (referred to as a divided region in the captured image). Then, the artificial defect pixel contrast and the non-defective pixel contrast are calculated by the above-described method (S14) (control value calculation step).

  The contrast calculation unit 56 associates the imaging position where the captured image is captured, information for specifying the divided area in the captured image, and the artificial defect pixel contrast and the non-defective pixel contrast in the divided area in association with each other. Output to.

  As described above, the degree-of-separation calculation unit 57 calculates the pixel-element contrast degree of separation from the artificial defect pixel contrast and the non-defective pixel contrast for each divided region in the captured image (S15). That is, the degree-of-separation calculation unit 57 calculates the pixel contrast separation degree for each divided region in the captured image for each of the captured images captured at each point in the section from the point A to the point B (separation degree). Calculation step).

  For example, the degree-of-separation calculation unit 57 calculates the absolute value of the difference value between the artificial defect pixel contrast of a certain divided region and the statistical value (for example, average value) of the non-defective pixel contrast of the divided region. Calculate as The degree-of-separation calculation unit 57 outputs the calculated pixel contrast separation degree to the degree-of-separation evaluation unit 58 in association with information specifying the imaging position where the captured image is captured and the divided area in the captured image.

  At this time, the separation degree evaluation unit 58 uses the horizontal axis as the imaging position on the Z axis of the camera 11 (position between point A and point B), and the vertical axis as the pixel contrast separation degree in FIG. As shown in c), a picture element contrast curve can be drawn for each divided area (in this case, three divided areas including an upper divided area, a central divided area, and a lower divided area).

  At this time, the optical axis is aligned, that is, the imaging target surface of the flat panel 40 and the surface of the imaging element 14 are parallel, and the optical axis of the lens unit 12 is perpendicular to both surfaces. Then, as shown in (c-2) of FIG. 9, the position where the pixel contrast separation degree of the central divided region peaks and the position where the pixel contrast separation degree of the other divided regions peaks Ideally match.

  However, in reality, the positions of the peak of the pixel contrast separation degree do not substantially coincide with each other due to the influence of aberration or the like (the details will be described later).

  Therefore, the separation degree evaluation unit 58 completely matches the position where the pixel contrast separation degree of the central divided region reaches a peak and the position where the pixel contrast separation degree of the other divided region reaches a peak, or If the difference between these positions is within an allowable range, it is determined that the optical axis has been adjusted at that time, and all adjustments are completed.

  That is, the separation degree evaluation unit 58 calculates the imaging position on the Z-axis of the camera 11 that maximizes the pixel contrast separation degree of the divided area in the captured image for each of the three divided areas (S16). Of the three imaging positions, it is determined whether or not the difference between the imaging position with the maximum Z-axis coordinate and the imaging position with the minimum Z-axis coordinate is within a predetermined range (optical axis adjustment value calculation step).

  If the difference is within the allowable range (YES in S17), separation degree evaluation unit 58 outputs to controller 6 an adjustment end command that instructs to end the adjustment.

  Upon receiving the adjustment end command, the controller 6 causes the camera 11 to image the flat panel 40 via the imaging control unit 2 and stores the captured image in the image memory 4 as a captured image for inspection. The captured image for inspection is analyzed by the inspection device 31 to determine whether the flat panel 40 has a defect.

  Note that the above-described allowable range is precisely the range of the difference between the imaging positions where the difference in the pixel contrast separation degree of each divided region is within the allowable range. For example, from the point of defect detection sensitivity, there is a specification of what percentage of variation (decrease amount) in the pixel contrast separation degree of the upper and lower divided regions with respect to the central divided region, and the optical axis is adjusted based on that specification In this case, even if the peak position of the pixel contrast separation is shifted between the upper, middle, and lower divided areas, the variation (decrease amount) in the pixel contrast separation of the upper and lower divided areas with respect to the central divided area is specified. If it is within, the deviation of the peak position is within the allowable range.

  On the other hand, when it is determined that the difference is not within the allowable range (NO in S17), separation degree evaluation unit 58 outputs to controller 6 a lens angle adjustment command that instructs adjustment of the angle of lens unit 12. To do.

  Upon receiving the lens angle adjustment command, the controller 6 causes the camera stage 15 to adjust the angle of the lens unit 12 with respect to the image sensor 14 via the camera position adjustment unit 3 (S18).

  At this time, the separation degree evaluation unit 58 uses the peak position of the pixel contrast separation degree in the central divided area as a reference, and the peak position of the pixel contrast separation degree in the other divided areas shifts in the positive direction of the Z axis. An adjustment value for adjusting the angle of the lens unit 12 is calculated based on whether the lens unit 12 is displaced in the negative direction, and the adjustment value is output to the camera position adjustment unit 3 (optical axis adjustment value calculation step).

  That is, the separability evaluation unit 58 obtains the maximum separability after obtaining the maximum separability, which is the separability having the maximum value, from the set of separability calculated for the specific subregion, for each subregion. The reached imaging position is compared between the divided areas, and an adjustment value for adjusting the angle of the lens unit 12 is calculated based on the comparison result.

  More specifically, the degree-of-separation evaluation unit 58 determines the smallest Z-axis coordinate among the imaging positions that give the maximum value of the pixel contrast separation degree for each of a plurality of divided areas (upper, central, and lower divided areas). An adjustment value for adjusting the angle of the lens unit 12 is calculated so that the difference between the imaging position having the maximum and the imaging position having the largest Z-axis coordinate is within a predetermined range.

  For example, the degree-of-separation evaluation unit 58 adjusts the angle of the lens unit 12 upward in the first trial, confirms the change in the peak position of the pixel contrast separation at that time, and in the second trial, the lens unit 12 It is only necessary to determine whether the lens unit 12 should be adjusted to the upper side or the lower side after confirming the change in the peak position when the angle of the lens is adjusted to the lower side.

  The camera position adjustment unit 3 adjusts the angle of the lens unit 12 by controlling the support jig 13 based on the adjustment value output from the separation degree evaluation unit 58.

  After completing this adjustment, the control device 1 performs the same imaging and picture element contrast calculation as described above in the section from the point A to the point B, and the picture element for the central divided area and the other divided areas. A difference in the peak position of the contrast separation degree is calculated, and it is determined whether or not the difference is within a predetermined range (return to S13). Thereafter, this operation is repeated until the difference between the peak position of the pixel contrast separation degree in the central divided region and the peak position of the pixel contrast separation degree in the other divided regions falls within an allowable range.

  As described above, when fine adjustment of the optical axis is performed, the control device 1 performs coarse adjustment of the optical axis, and when no adjustment is performed in the coarse adjustment of the optical axis or the fine adjustment of the optical axis, That is, in the rough adjustment of the optical axis, the angle adjustment around the X, Y, and Z axes is performed. In the fine adjustment of the optical axis, when the process is finished without fine adjustment of the angle of the lens unit 12, all the optical axes are obtained. Complete the adjustment.

  Then, the final position of the origin determined by repeating the coarse adjustment and fine adjustment of the optical axis becomes the position where the captured image for defect inspection is captured. Strictly speaking, it is preferable to perform fine adjustment of the origin by checking the imaging resolution (whether the imaging resolution is as specified) when updating the origin.

  In the above-described configuration, the optical axis is finely adjusted using the pixel contrast separation degree as an index. However, the same adjustment can be performed using the artificial defect pixel contrast itself as an index. However, when the artificial defect pixel contrast itself is used as an index, for example, at the position where the artificial defect pixel contrast reaches its peak, the non-defective pixel contrast also becomes the peak position (that is, the noise level also increases), and as a result, the contrast separation degree is not necessarily limited. There may be cases where the position does not reach its maximum. Therefore, from the viewpoint of "inspection sensitivity", it is better to use "separation between artificial defect pixel contrast and non-defective pixel contrast (normalized artificial defect pixel contrast with non-defective pixel contrast)" as an index. Appropriate adjustments can be made.

  When fine adjustment of the optical axis is performed using the artificial defect pixel contrast itself as an index, the separation degree calculation unit 57 and the separation degree evaluation unit 58 are not necessary, and the contrast calculation unit 56 performs the artificial defect pixel element contrast (first operation). The control value is calculated for each divided region for each captured image, and the relationship between the artificial defect pixel contrast for each divided region and the imaging position at which the captured image used to calculate the artificial defect pixel contrast is captured Based on the above, the optical axis adjustment value for adjusting the relative position between the lens unit 12 and the image sensor 14 is calculated so that the difference in the artificial defect pixel contrast for each divided region falls within a predetermined range.

(Problems and solutions)
FIG. 10 is a graph showing an ideal state of optical axis matching and an actual state. FIG. 11 is a diagram for explaining the problem of optical axis adjustment.

  When all the optical axis adjustments are completed, that is, when the peak positions of the pixel contrast separation degrees in the upper, middle, and lower divided regions are substantially the same, the pixel contrast separation in each divided region of the flat panel 40 is performed. The degree is the most separated state (the state in which the pixel contrast separation degree is the largest) and ideally the state where the curves match. Such an ideal state is shown in FIG.

  In particular, if an artificial defect pixel having a luminance at the boundary level of defect detection (for example, an artificial defect pixel having luminance equivalent to the vicinity of the viewing limit) is used, the defective pixel is detected in the entire plane of the flat panel 40. The threshold for doing so can be easily determined.

However, as described above, due to various factors such as aberration, panel viewing angle characteristics, and pixel variation (individual difference), an ideal result is not obtained as shown in FIG. actually,
(A) The imaging positions in the Z-axis direction of the camera 11 at which the pixel contrast separation degree of the central divided area and the other divided areas reach a peak do not completely match, or
(B) The problem that the pixel contrast separation degree in each divided region does not completely match at the position on the Z axis of the camera 11 where the pixel contrast separation degree of the central divided region and the other divided regions reaches a peak. Occurs.

  Specifically, the problem (A) is mainly caused by lens aberration (field curvature). This hinders optical axis adjustment particularly in the following cases.

  For example, when the arrangement of the artificial defect picture elements is as shown in FIG. 11B, that is, the arrangement of the artificial defect picture elements passes through the center of the flat panel 40 and is parallel to the Y-axis direction. When the axis of symmetry is not line symmetric, the peak positions of the pixel contrast separation in the upper divided region and the lower divided region are shifted from each other even when the optical axis is adjusted.

  In such a state, it becomes impossible to distinguish whether the peak position is shifted due to an optical axis problem or an aberration problem, and the upper, middle, and lower divided regions are not separated as described above. If the peak positions of the pixel contrast separation are matched or adjusted so that the difference falls within the allowable range, the result is inappropriate as optical axis adjustment.

  In order to avoid this problem, the position of the artificial defect pixel in the optical axis adjustment pattern is made symmetrical with respect to an axis passing through the center of the flat panel 40 and parallel to the X-axis direction or the Y-axis direction. Can be avoided. For example, artificial defect picture elements are arranged as shown in FIG. In this way, it is possible to determine that the peak position deviation of the pixel contrast separation degree of the upper and lower divided regions and the central divided region is a problem of lens aberration, and based on the determination, the upper, middle, What is necessary is just to adjust an optical axis so that the difference of the peak position of the pixel contrast separation degree of a lower division area may be in an allowable range.

On the other hand, the problem (B) is mainly caused by the following factors. That is,
(i) Image sensor variation,
(ii) Panel TFT variation,
(iii) Variation in in-plane distribution of backlight (including shading by lens),
(iv) The viewing angle characteristics of the panel.

  Of course, the peak position is shifted due to the problem (A), which also causes the problem (B).

  All of these are factors that affect (scatter) the magnitude of the pixel contrast separation value. The magnitude of the pixel contrast separation degree is not particularly problematic from the viewpoint of optical axis adjustment accuracy, but is not desirable from the viewpoint of quantitatively adjusting the optical axis for defect detection sensitivity.

  That is, when the pixel contrast separation degree varies due to the above factors, a defective pixel element having a specific range of luminance is determined based on the value of the pixel contrast separation degree when the optical axis is finely adjusted. It is impossible to guarantee that detection is possible at various points in the 40 planes.

  For these problems (I) to (iv), the following measures can be taken to reduce the influence on the variation in the pixel contrast separation degree.

  As an example of measures against (I), it is possible to remove dark noise (dark current noise) of the camera 11 before imaging the flat panel 40.

  As an example of measures against (ii), it is possible to suppress variations by arranging a plurality of artificial defect picture elements in the same divided region and using a plurality of defect picture element contrast values.

  As a countermeasure example for (iii), shading correction may be performed before the flat panel 40 is imaged.

  As an example of measures against (iv), the optical axis adjustment panel is set so that each of the divided regions is line-symmetric with respect to an axis parallel to the X-axis direction or the Y-axis direction passing through the center of the flat panel 40. To set.

(Effect of automatic inspection system 30)
As described above, in the automatic inspection system 30, in the captured image obtained by capturing the flat panel 40 with the camera 11, the pixel contrast separation degree is maximized in the region corresponding to the central portion of the flat panel 40, and further, the flatness in the captured image is displayed. The optical axis of the camera 11 is adjusted so that the picture element contrast separation degree at each position in the plane of the panel 40 is substantially uniform.

  Therefore, it is possible to realize an optical axis state that is optimal for the inspection of the flat panel, and to perform a defect inspection that can guarantee that a defective picture element having a specific range of luminance can be detected at various locations in the plane of the flat panel 40. .

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIGS. In addition, about the member similar to Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  FIG. 12 is a diagram illustrating an example of changing the optical axis adjustment pattern. In the above description, the pattern of the artificial defect picture element as shown in FIG. 5 is given as an example of the optical axis adjustment pattern, but the flat panel 40 to be inspected cannot display the artificial defect picture element itself. When only the flat pattern can be displayed, as shown in FIG. 12, two flat patterns A and B are imaged, and the captured image A of the flat pattern A and the captured image B of the flat pattern B are synthesized. Then, the defect pixel contrast and the non-defective pixel contrast may be calculated using the image (the composite image C).

  The flat pattern A is a lighting pattern in which the entire surface of the flat panel 40 is turned on at a luminance corresponding to a non-defective pixel (second luminance), and the flat pattern B is a luminance corresponding to a defective pixel (first luminance). (Luminance) is a lighting pattern in which the entire surface of the flat panel 40 is lit.

  The automatic inspection system 50 according to the present embodiment uses the composite image C to calculate a defective pixel contrast and a non-defective pixel contrast.

(Configuration of automatic inspection system 50)
FIG. 13 is a conceptual diagram showing the configuration of the automatic inspection system 50. As shown in FIG. 13, the automatic inspection system 50 includes a control device (optical axis adjustment value calculation device) 60 that calculates a defective pixel contrast and a non-defective pixel contrast using the composite image C.

  The control device 60 includes an image composition unit (image composition unit) 61 that synthesizes the captured image A (second captured image) and the captured image B (first captured image) to generate a composite image C. More specifically, the image composition unit 61 synthesizes a captured image A and a captured image B having the same image capturing position, thereby at least selected from a plurality of divided regions generated by dividing the screen of the flat panel 40. A composite image representing a state in which at least one first mark having the first luminance and a second mark having the second luminance are displayed in each of the two divided regions (that is, the optical axis shown in FIG. 5). An image corresponding to a captured image obtained by capturing the adjustment pattern) is generated.

(Processing in the automatic inspection system 50)
The difference in processing between the automatic inspection system 50 and the automatic inspection system 30 is that, in the process of finely adjusting the optical axis, the automatic inspection system 30 images the flat panel 40 displaying the optical axis adjustment pattern. The automatic inspection system 50 is that the camera 11 images the flat panel 40 displaying the flat pattern A and the flat panel 40 displaying the flat pattern B at the same imaging position.

  The imaging control unit 2 stores the acquired captured image A and captured image B in the image memory 4. The image composition unit 61 generates a composite image C by combining the captured image A and the captured image B, which are stored in the image memory 4 and have the same image capturing position, and associates the generated composite image C with the image capturing position. Then, it is stored in the image memory 4.

  That is, the imaging control unit 2 captures a plurality of captured images B captured by the camera 11 while moving the flat panel 40 displaying the flat pattern B on a perpendicular line from the camera 11 to the flat panel 40. Are acquired in association with each other, and a plurality of captured images A captured by the camera 11 in the same manner as the captured image B are acquired in association with the imaging positions of the flat panel 40 displaying the flat pattern A.

  The optical axis fine adjustment unit 55 of the image processing unit 5 uses the composite image C to calculate an adjustment value for fine adjustment of the optical axis by the same method as described above.

  Since it is the same as that of the automatic test | inspection system 30 except the difference mentioned above, description about the other process regarding the automatic test | inspection system 50 is abbreviate | omitted.

(Effect of automatic inspection system 50)
As described above, in the automatic inspection system 50, even when the flat panel to be imaged (inspected) can display only the flat pattern, the optical axis is finely adjusted in the same manner as the flat panel capable of displaying the optical axis adjustment pattern. be able to.

(Example of change)
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  Each block of the control device 1 and the control device 60 described above, particularly the image processing unit 5, may be configured by hardware logic, or may be realized by software using a CPU as follows.

  That is, the control device 1 and the control device 60 include a central processing unit (CPU) that executes instructions of a control program that realizes each function, a read only memory (ROM) that stores the program, and a RAM (random) that expands the program. access memory), a storage device (recording medium) such as a memory for storing the program and various data. The object of the present invention is the program code (execution format program, intermediate code program, source program) of the control program (optical axis adjustment value calculation program) of the control device 1 and the control device 60, which is software that realizes the functions described above. Is supplied to the control device 1 and the control device 60, and the computer (or CPU or MPU) reads and executes the program code recorded on the recording medium. Achievable.

  Examples of the recording medium include a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, and an optical disk such as a CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  The control device 1 and the control device 60 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Also, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  The present invention can also be expressed as follows.

  That is, the imaging system optical axis adjustment method according to the present invention supports the imaging element, the lens unit, and the angle of the lens unit with respect to the imaging element in the inspection of the inspection object by imaging a to-be-inspected object. An imaging system having means, means for displaying or installing linear markers A and B parallel to the imaging target plane and orthogonal to each other, and two orthogonal directions parallel to the imaging target area are defined as an X axis and a Y axis, When the normal direction of the imaging target area surface is the Z axis, the imaging system moving means for moving the imaging system, and the attitude of the imaging system around the Z axis from an image obtained by imaging at least one of the marker A and the marker B Means for detecting, means for detecting the posture of the imaging system around the Y axis and around the X axis from images taken sequentially while moving the marker A and marker B in the Z axis direction, and for each axis based on each detection versus A mechanism and means for adjusting the posture of the imaging system, means for displaying a pattern C having light and shade gradations in each of the divided areas obtained by dividing the imaging target area into at least three parts, and moving the pattern C in the Z-axis direction Means for calculating a set of optical evaluation index values for each divided region at each position from sequentially captured images, and means for adjusting the optical axis of the imaging system from the set of optical index values It is characterized by that.

  In the imaging system optical axis adjustment method, the pattern C is an artificial defect pattern having a defect portion and a non-defective portion of the inspection object, and the optical index value is the pixel contrast of the defect portion of the pattern C and the non-defective portion. The pixel contrast separation degree of the pixel contrast is preferable.

  The picture element contrast refers to the difference / ratio between the gray value of the corresponding picture element and the gray value of the same color picture element in the vicinity thereof, and is represented on the basis of general image contrast (image standard deviation or the like). (Sharpness) has a different meaning.

  Further, in the imaging system optical axis adjustment method, the artificial defect pattern is a pattern formed by combining two types of flat patterns D and E having different gradations once, and the optical index value is the flat value. A state in which one of the patterns D and E is used as a reference pattern, and a gray value corresponding to a specific pixel group F in the reference pattern is replaced with a gray value corresponding to a pixel group at the same position as the pixel group F in the other flat pattern In the reference pattern, the pixel contrast of the pixel group F in the reference pattern and the pixel contrast separation degree of the pixel contrast of the other part are preferably used.

  The imaging system optical axis adjusting device of the present invention includes a support unit capable of adjusting an angle of the lens unit with respect to the imaging element, the lens unit, and the imaging element in the inspection of the inspection object by imaging the inspection object capable of gradation display. An imaging system having an imaging system, means for displaying or installing linear markers A and B parallel to the imaging target plane and orthogonal to each other, and two orthogonal directions parallel to the imaging target area as an X axis and a Y axis. An imaging system moving unit that moves the imaging system when the normal direction of the surface is the Z axis, and a unit that detects the posture of the imaging system around the Z axis from an image obtained by imaging at least one of the marker A and the marker B And means for detecting the posture of the imaging system around the Y axis and around the X axis from images taken sequentially while moving the marker A and marker B in the Z axis direction, and the imaging system for each axis based on each detection Appearance And a mechanism and means for displaying a pattern C having a light and shade gradation in each of the divided area areas obtained by dividing the imaging target area into at least three areas, and sequentially imaging while moving the pattern C in the Z-axis direction. Means for calculating a set of optical evaluation index values for each divided region at each position from the obtained image, and means for adjusting the optical axis of the imaging system from the set of optical index values. .

  In the imaging system optical axis adjustment device, the pattern C is an artificial defect pattern having a defect portion and a non-defective portion of the inspection object, and the optical index value is the pixel contrast of the defect portion of the pattern C and the non-defective portion. The pixel contrast separation degree of the pixel contrast is preferable.

  In the imaging system optical axis adjusting device, the artificial defect pattern is a pattern formed by combining two types of flat patterns D and E having different gradations once, and the optical index value is the flat value. A state in which one of the patterns D and E is used as a reference pattern, and a gray value corresponding to a specific pixel group F in the reference pattern is replaced with a gray value corresponding to a pixel group at the same position as the pixel group F in the other flat pattern In the reference pattern, the pixel contrast of the pixel group F in the reference pattern and the pixel contrast separation degree of the pixel contrast of the other part are preferably used.

  Calculates an adjustment value for adjusting the optical axis of the imaging device so that the display device can acquire a captured image of the display device that can detect a pixel having a luminance different from that of surrounding pixels with high accuracy. Therefore, the present invention can be applied to an imaging system that acquires a captured image used by an automatic inspection apparatus that performs automatic inspection of a display device or an automatic inspection system that includes an automatic inspection apparatus.

It is a functional block diagram which shows the structure of an image process part. It is the schematic which shows the structure of the automatic inspection system which concerns on one Embodiment of this invention. It is the schematic which shows the structure of the said automatic test | inspection system in detail. It is a conceptual diagram which shows the marker for the coarse adjustment of an optical axis displayed on a flat panel. It is a figure which shows the example of the pattern for optical axis adjustment. It is a figure for demonstrating an example of the calculation method of picture element contrast and picture element contrast isolation | separation degree. It is a flowchart which shows an example of the procedure of the rough adjustment of an optical axis. It is a figure which shows the angle adjustment method of a camera. It is a flowchart which shows an example of the procedure of fine adjustment of an optical axis. It is a graph which shows the ideal state in which the optical axis is in agreement, and an actual state. It is a figure for demonstrating the problem of optical axis adjustment. It is a figure which shows the example of a change of the pattern for optical axis adjustment. It is a conceptual diagram which shows the structure of the automatic inspection system which concerns on another embodiment of this invention.

Explanation of symbols

1 Control device (Optical axis adjustment value calculation device)
2 Imaging control unit (captured image acquisition means)
5 Image processing unit (optical axis adjustment value calculation device)
11 Camera (imaging device)
12 Lens unit (optical element)
14 Image sensor 40 Flat panel (display device)
51 Optical axis coarse adjustment unit (attitude adjustment value calculation means)
55 Optical axis fine adjustment unit (Optical axis adjustment value calculation device)
56 Contrast calculation part (control value calculation means)
57 Separation degree calculation unit (separation degree calculation means)
58 Separation degree evaluation unit (optical axis adjustment value calculation means)
60 Control device (optical axis adjustment value calculation device)
61 Image composition unit (image composition means)

Claims (9)

Adjustment for adjusting the position of the optical axis of the optical element by analyzing the picked-up image picked up by the image pick-up device on the image of the display device, which is the object to be picked up, formed on the surface of the image pick-up element by the optical element An optical axis adjustment value calculation device for calculating a value,
The first mark is different from at least one first mark displayed in each of at least two divided areas selected from a plurality of divided areas generated by dividing the screen of the display device and having the same brightness. Corresponding to a plurality of captured images captured by the imaging device while moving an adjustment pattern including a second mark having the same luminance on the vertical line from the imaging device to the display device Captured image acquisition means for acquiring and attaching,
For each captured image acquired by the captured image acquisition means, a first reference value indicating a difference between a luminance value of a pixel corresponding to the first mark and a luminance value of a pixel corresponding to the second mark, and the second Contrast value calculating means for calculating a second contrast value indicating a difference in luminance values of a plurality of pixels corresponding to the mark for each divided region;
The degree of separation for calculating for each divided region the degree of separation indicating how far the first reference value and the second reference value calculated by the reference value calculating unit are separated for each captured image acquired by the captured image acquisition unit A calculation means;
Based on the relationship between the degree of separation for each divided region calculated by the above-described degree of separation calculation unit and the imaging position where the captured image used to calculate the degree of separation is captured, the degree of separation for each divided region is calculated. An optical axis adjustment value calculating means for calculating an optical axis adjustment value for adjusting a relative position between the optical element and the imaging element so that the difference falls within a predetermined range. Adjustment value calculation device. Adjustment for adjusting the position of the optical axis of the optical element by analyzing the picked-up image picked up by the image pick-up device on the image of the display device, which is the object to be picked up, formed on the surface of the image pick-up element by the optical element An optical axis adjustment value calculation device for calculating a value,
A plurality of first captured images captured by the imaging device while moving on a vertical line extending from the imaging device to the display device with a display device having the entire screen lit at the first luminance, And a plurality of second images obtained by imaging the display device in the same manner as the first captured image, the display device having the entire surface lit at a second luminance different from the first luminance. Captured image acquisition means for acquiring an image in association with the imaging position;
By combining the first and second captured images having the same imaging position acquired by the captured image acquisition means, at least two selected from a plurality of divided regions generated by dividing the screen of the display device Image combining means for obtaining a combined image representing a state in which at least one first mark having the first luminance and a second mark having the second luminance are displayed in each of the divided regions;
For each synthesized image synthesized by the image synthesizing means, a first reference value indicating a difference between a luminance value of a pixel corresponding to the first mark and a luminance value of a pixel corresponding to the second mark, and the second mark Contrast value calculating means for calculating a second reference value indicating a difference in luminance values of a plurality of pixels corresponding to each divided region;
The degree-of-separation calculation for calculating for each divided region the degree of separation indicating how far the first control value and the second reference value calculated by the control value calculation means are separated for each composite image synthesized by the image composition means Means,
Based on the relationship between the degree of separation for each divided region calculated by the separation degree calculating means and the imaging position corresponding to the composite image used to calculate the degree of separation, the degree of separation for each divided region is calculated. An optical axis adjustment value calculating means for calculating an optical axis adjustment value for adjusting a relative position between the optical element and the imaging element so that the difference falls within a predetermined range. Adjustment value calculation device.   The optical axis adjustment value calculating means obtains the maximum degree of separation after obtaining the maximum degree of separation for each divided area from the set of degrees of separation calculated for the specific divided area for each divided area. 3. The optical axis adjustment value calculation apparatus according to claim 1, wherein the obtained imaging position is compared between the divided areas, and the optical axis adjustment value is calculated based on the comparison result. The first mark is an artificial defect pixel having a luminance outside a predetermined range,
The optical axis adjustment value calculation apparatus according to any one of claims 1 to 3, wherein the second mark is a non-defective picture element having a luminance within a predetermined range.   Characterized by further comprising posture adjustment value calculation means for calculating a posture adjustment value for adjusting a relative position between the display device and the imaging device by analyzing a captured image obtained by capturing an image of the display device. The optical axis adjustment value calculation apparatus according to any one of claims 1 to 4.   An optical axis adjustment value calculation program for operating the optical axis adjustment value calculation apparatus according to claim 1, wherein the computer functions as each of the means.   A computer-readable recording medium on which the optical axis adjustment value calculation program according to claim 6 is recorded. Adjustment for adjusting the position of the optical axis of the optical element by analyzing the picked-up image picked up by the image pick-up device on the image of the display device, which is the object to be picked up, formed on the surface of the image pick-up element by the optical element An optical axis adjustment value calculation method in an optical axis adjustment value calculation device for calculating a value,
The first mark is different from at least one first mark displayed in each of at least two divided areas selected from a plurality of divided areas generated by dividing the screen of the display device and having the same brightness. Corresponding to a plurality of captured images captured by the imaging device while moving an adjustment pattern including a second mark having the same luminance on the vertical line from the imaging device to the display device A captured image acquisition step of acquiring and attaching,
For each captured image acquired in the captured image acquisition step, a first reference value indicating a difference between a luminance value of a pixel corresponding to the first mark and a luminance value of a pixel corresponding to the second mark, and the first A contrast value calculating step of calculating, for each divided region, a second contrast value indicating a difference in luminance values of a plurality of pixels corresponding to two marks;
For each captured image acquired in the captured image acquisition step, a degree of separation indicating how far the first control value and the second control value calculated in the control value calculation step are separated is calculated for each divided region. A separation degree calculating step;
The degree of separation for each divided region based on the relationship between the degree of separation for each divided region calculated in the step of calculating the degree of separation and the imaging position at which the captured image used to calculate the degree of separation is captured. An optical axis adjustment value calculating step for calculating an optical axis adjustment value for adjusting a relative position between the optical element and the imaging element so that the difference between the optical element and the imaging element falls within a predetermined range. Axis adjustment value calculation method. Adjustment for adjusting the position of the optical axis of the optical element by analyzing the picked-up image picked up by the image pick-up device on the image of the display device, which is the object to be picked up, formed on the surface of the image pick-up element by the optical element An optical axis adjustment value calculation method in an optical axis adjustment value calculation device for calculating a value,
A plurality of first captured images captured by the imaging device while moving on a vertical line extending from the imaging device to the display device with a display device having the entire screen lit at the first luminance, And a plurality of second images obtained by imaging the display device in the same manner as the first captured image, the display device having the entire surface lit at a second luminance different from the first luminance. A captured image acquisition step of acquiring an image in association with the imaging position;
At least 2 selected from a plurality of divided regions generated by dividing the screen of the display device by combining the first and second captured images having the same imaging position acquired in the captured image acquisition step. An image synthesizing step for obtaining a synthesized image representing a state in which at least one first mark having the first luminance and a second mark having the second luminance are displayed in each of the two divided regions;
For each synthesized image synthesized in the image synthesizing step, a first reference value indicating a difference between a luminance value of a pixel corresponding to the first mark and a luminance value of a pixel corresponding to the second mark, and the second A contrast value calculating step for calculating, for each divided region, a second contrast value indicating a difference in luminance values of a plurality of pixels corresponding to the mark;
Separation for calculating for each divided region a degree of separation indicating how far the first control value and the second control value calculated in the control value calculation step are separated for each composite image synthesized in the image synthesis step Degree calculation step,
The degree of separation for each divided region based on the relationship between the degree of separation for each divided region calculated in the separation degree calculation step and the imaging position corresponding to the composite image used to calculate the degree of separation. An optical axis adjustment value calculating step for calculating an optical axis adjustment value for adjusting a relative position between the optical element and the imaging element so that the difference between the optical element and the imaging element falls within a predetermined range. Axis adjustment value calculation method.