WO2021053852A1 - Appearance inspection device, appearance inspection device calibration method, and program - Google Patents

Appearance inspection device, appearance inspection device calibration method, and program Download PDF

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Publication number
WO2021053852A1
WO2021053852A1 PCT/JP2020/008748 JP2020008748W WO2021053852A1 WO 2021053852 A1 WO2021053852 A1 WO 2021053852A1 JP 2020008748 W JP2020008748 W JP 2020008748W WO 2021053852 A1 WO2021053852 A1 WO 2021053852A1
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Prior art keywords
calibration
feature amount
visual inspection
inspection apparatus
image
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PCT/JP2020/008748
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French (fr)
Japanese (ja)
Inventor
貴茂 田中
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オムロン株式会社
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Publication of WO2021053852A1 publication Critical patent/WO2021053852A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/93—Detection standards; Calibrating baseline adjustment, drift correction

Definitions

  • the present invention relates to an appearance inspection device that inspects an inspected object based on an image of the inspected object taken by irradiating the inspected object with illumination light, and a calibration method thereof.
  • Patent Document 1 discloses an apparatus for inspecting the appearance of a substrate by combining three-dimensional shape measurement of a mirrored object by a so-called color highlighting method and three-dimensional shape measurement of a diffused object by a so-called phase shift method. There is.
  • the optical system consisting of a light source that irradiates illumination light and an imaging device such as a camera may not be able to exhibit its original performance over time depending on the frequency of use and the environment. By implementing this, it is common to readjust and use it so that the original performance can be exhibited.
  • the above calibration is performed as follows.
  • a jig standard plate or the like
  • the surface of the jig (hereinafter, also referred to as a standard surface) is photographed by a photographing device (that is, the light reflected by the jig is received).
  • the brightness value is extracted from the image taken by the photographing device, and if the value deviates from the preset reference value, the current value on the light source side is adjusted so as to approach the reference value for illumination. Adjust the conditions, irradiate and shoot again. In this way, adjustment is performed so that the extracted luminance value becomes a reference value.
  • the cleanliness of the standard surface is very important. That is, if dust (dust, etc.) or dirt adheres to the standard surface, they are reflected in the captured image, and the brightness value of the portion concerned fluctuates greatly, so that accurate calibration cannot be realized.
  • the present invention has been made in view of the above circumstances, and in the calibration of a visual inspection apparatus performed by photographing a standard surface for calibration, accurate calibration is performed without strictly maintaining the cleanliness of the standard surface.
  • the purpose is to provide a technology that can realize the above.
  • the present invention adopts the following configuration.
  • the visual inspection apparatus is Lighting means that irradiates the object to be inspected with illumination light, An imaging means for photographing the object to be inspected and a standard surface for calibration prepared for calibration. An inspection means for inspecting the object to be inspected by processing an image taken by the photographing means, and an inspection means for inspecting the object to be inspected. A predetermined feature amount is extracted from a plurality of images of the calibration standard surface photographed by the imaging means in a state where the relative positions in the direction parallel to the calibration standard surface are different from those of the imaging means, and the extracted features are extracted. An adjustment feature amount calculation means that calculates one adjustment feature amount based on the values of a plurality of feature amounts, and an adjustment feature amount calculation means. With Based on the adjustment feature amount, the lighting means is calibrated and / or the captured image is corrected.
  • the above feature quantities can be, for example, brightness, brightness, saturation, and the like.
  • the standard surface for calibration may be provided on a standard plate separate from the visual inspection device, and the standard plate may be arranged on the visual inspection device for calibration, or may be built in the visual inspection device. It may be the one that has been calibrated.
  • the visual inspection device may further include a calibration standard plate, and the calibration standard surface may be provided on the calibration standard plate.
  • the appearance device may further include a moving mechanism for moving the calibration standard plate and / or the photographing means in the horizontal direction.
  • the calibration standard surface is photographed while moving the imaging means and the calibration standard surface relatively little by little in a direction parallel to each other, so that the imaging means and the calibration standard surface can be easily positioned relative to each other. Can acquire multiple images with different values.
  • the adjustment feature amount calculating means extracts the gradation value of the feature amount of the plurality of images for each region of 1 ⁇ 1 pixel or more, and the floor of each region extracted from the plurality of images.
  • the mode value of the adjustment price may be set as the adjustment feature amount in the region.
  • the term "gradation” used here does not only indicate the lightness and darkness of the image, but also includes the lightness and the degree of saturation in the color. Further, the "gradation value” does not mean only the value of the gradation itself of the feature amount possessed by the pixel of the image data, for example, in 256 steps from 0 to 255, but the feature amount has a range of a certain value.
  • the value set as the representative value for each stage by dividing the level into several stages so as to have it. Specifically, for example, when the gradation values from 0 to 255 are classified into 25 stages and the representative values of each stage are 10, 20, 30, ..., The representative values are included.
  • the gradation value of the feature amount when the region is composed of a plurality of pixels can be an average value, a mode value, or the like of the gradation values of each pixel constituting the region.
  • the adjustment feature amount for each region is not necessarily limited to the mode value of the plurality of gradation values, and may be, for example, the average value or the median value of the plurality of gradation values. , May be the maximum value.
  • the visual inspection device further includes a lighting condition setting means for setting the lighting condition of the illumination light, and the lighting condition setting means has the adjustment feature amount and the preset reference feature amount. By setting the illumination conditions of the illumination light based on the comparison, the illumination means may be calibrated.
  • the lighting conditions can be appropriately reset and the visual inspection of the object to be inspected can be performed.
  • the appearance inspection device further includes a correction image generation means for generating a correction image using the adjustment feature amount, and the correction processing of the image is performed by the inspection means based on the correction image. Therefore, the shading correction of the image captured by the photographing means may be performed.
  • the correction image can be, for example, an image in which the value of each pixel is used as the adjustment feature amount, and by using such image data as a reference for shading correction of the captured image, highly accurate shading correction can be performed. It can be performed.
  • the shading correction is a correction for correcting aberrations of the observation optical system in the captured image.
  • the calibration method of the visual inspection apparatus is described. It is a method of calibrating the visual inspection device that inspects the inspected object based on the image of the inspected object taken by irradiating the inspected object with illumination light.
  • the calibration method referred to here is used to mean not only the calibration method of the optical system but also the correction method in image processing.
  • the calibration standard surface and / or the imaging means is moved in a direction parallel to the calibration standard surface, and the relative position of the calibration standard surface and the imaging means in a direction parallel to the imaging means is set.
  • a plurality of images of the standard surface for calibration in different states may be taken.
  • the gradation values of the feature amounts of the plurality of images are extracted for each region of 1 ⁇ 1 pixel or more, and in the calculation step, the said region for each of the plurality of images extracted.
  • the mode value of the gradation value may be used as the adjustment feature amount in the region.
  • the illumination conditions of the illumination light may be calibrated by comparing the adjustment feature amount with the preset reference feature amount.
  • a correction image may be generated using the adjustment feature amount, and shading correction of the image of the object to be inspected may be performed based on the correction image.
  • the present invention can be regarded as a program for causing the visual inspection apparatus to execute the above method, and as a computer-readable recording medium in which such a program is recorded non-temporarily.
  • FIG. 1 is a schematic view showing a configuration of a visual inspection apparatus according to an application example of the present invention.
  • FIG. 2 is a flowchart showing a flow of calibration processing of the visual inspection apparatus according to the application example of the present invention.
  • FIG. 3A is a first diagram showing the relationship between the calibration standard plate and the photographing range.
  • FIG. 3B is a second diagram showing the relationship between the calibration standard plate and the photographing range.
  • FIG. 3C is a third diagram showing the relationship between the calibration standard plate and the photographing range.
  • FIG. 3D is a fourth diagram showing the relationship between the calibration standard plate and the photographing range.
  • FIG. 3E is a fifth diagram showing the relationship between the calibration standard plate and the photographing range.
  • FIG. 3A is a first diagram showing the relationship between the calibration standard plate and the photographing range.
  • FIG. 3B is a second diagram showing the relationship between the calibration standard plate and the photographing range.
  • FIG. 3C is a third diagram showing the relationship between the calibration standard
  • FIG. 3F is a sixth diagram showing the relationship between the calibration standard plate and the photographing range.
  • FIG. 4 is a schematic view showing the configuration of the substrate inspection apparatus according to the first embodiment.
  • FIG. 5 is a plan view illustrating the configuration of the lighting device according to the first embodiment.
  • FIG. 6 is a block diagram illustrating a function of the information processing apparatus according to the first embodiment.
  • FIG. 7 is a flowchart showing the flow of the substrate inspection process of the substrate inspection apparatus according to the first embodiment.
  • FIG. 1 is a schematic schematic view showing a schematic configuration of an appearance inspection device 9 according to this application example.
  • the visual inspection device 9 is a device that takes an image of an inspection object (not shown) and inspects the inspection object based on the image, and as shown in FIG. 1, the main configuration is illumination as a lighting means. It has a device 91, a camera 92 as an imaging means, an information processing device 93 (for example, a computer) as an inspection means, and a moving mechanism 94.
  • the lighting device 91 is configured to be able to irradiate the inspection object and the calibration standard plate 95 with illumination light.
  • the camera 92 is a photographing means for photographing an inspection object in a state of being irradiated with illumination light and a calibration standard plate 95 and outputting a digital image.
  • the image of the inspection object taken by the photographing means will be referred to as an observation image
  • the image of the calibration standard plate 95 will be referred to as a calibration image.
  • the camera 92 includes, for example, an optical system and an image sensor.
  • the information processing device 93 has functions such as control of a lighting device 91, a camera 92, and a moving mechanism 94, processing of an image captured from the camera 92, and three-dimensional shape measurement, and corresponds to the inspection means in the present invention. ..
  • the information processing device 93 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a non-volatile storage device (for example, a hard disk drive, a flash memory, etc.), an input device (for example, a keyboard, a mouse, a touch panel, etc.), and a display. It can be configured by a computer equipped with a device (eg, a liquid crystal display, etc.).
  • the moving mechanism 94 also serves as a stage on which the inspection object or the standard plate 95 for calibration is placed, and is driven by an actuator such as a motor (not shown) in the X-axis direction and the Y-axis shown in FIG. Move in the direction, and if the inspection object or the calibration standard plate 95 is placed, move these as well.
  • an actuator such as a motor (not shown) in the X-axis direction and the Y-axis shown in FIG. Move in the direction, and if the inspection object or the calibration standard plate 95 is placed, move these as well.
  • the calibration standard plate 95 is, for example, a white plate member that reflects the illumination light from the illumination device 91 to the camera 92.
  • the illumination light reflecting surface of the calibration standard plate 95 (that is, the surface imaged by the camera 92) corresponds to the calibration standard surface in the present invention.
  • the calibration standard plate 95 may be a separate body from the visual inspection device 9, or may be incorporated in the device.
  • the appearance inspection device 9 When the appearance inspection device 9 having the above configuration performs the appearance inspection of the inspection object, a plurality of images of the inspection object in a state of being irradiated with the illumination light from the lighting device 91 are photographed by the camera 92 and photographed.
  • the information processing apparatus 93 inspects the inspected object by performing image processing on the generated image by a method such as a color highlighting method.
  • the information processing device 93 includes an image acquisition unit 931, an adjustment feature amount calculation unit 932, a calibration processing unit 933, a lighting condition setting unit 934, and a movement mechanism control unit 935 as functional modules related to visual inspection.
  • the image acquisition unit 931 is a function of capturing an image from the camera 92. For example, in addition to an observation image of an inspection object irradiated with illumination light, a plurality of calibration images obtained by photographing a calibration standard plate 95 are acquired. .. For example, in this application example, six calibration image data obtained by photographing different parts of the calibration standard plate 95 are acquired.
  • the adjustment feature amount calculation unit 932 is a function for calculating the adjustment feature amount used for calibration. For example, in this application example, a feature amount (for example, a luminance value) possessed by each pixel of the image is extracted from each of the six calibration image data acquired by the image acquisition unit 931, and based on this, one pixel is extracted. Calculate the adjustment feature amount of. For example, for each pixel, the mode value of the data of the six luminance values extracted from the six image data is obtained, and the value of the mode value is used as the adjustment feature amount. For example, when the brightness values of a certain pixel obtained from the six calibration images are three for 200, two for 150, and one for 100, the adjustment feature amount of the pixel is set to 200. In this example, it can be considered that some obstacles such as dust and dirt have occurred in the places where the normal standard surface has a brightness value of 200 and the brightness values are 150 and 100.
  • the calibration processing unit 933 is a function of comparing and calibrating the adjustment feature amount calculated by the adjustment feature amount calculation unit 932 with the preset calibration reference value, and whether or not there is a difference between the two values. Find out whether the value of is high or its degree.
  • the illumination condition setting unit 934 is a function of setting the illumination condition by the illumination device 91, and the adjustment feature amount extracted from the calibration image based on the result obtained by the calibration processing unit 933 is the calibration reference value. Processing such as changing the current value of the lighting device 91 is performed so as to match with.
  • the movement mechanism control unit 935 is a mechanism that controls the drive of the movement mechanism 94, and controls an actuator for moving the movement mechanism 94 based on a user's input, a predetermined program, or the like.
  • the information processing device 93 controls the lighting device 91 and irradiates the calibration standard plate with the lighting light (step S901).
  • the information processing device 93 controls the camera 92 to take a picture of the calibration standard plate 95 in a state of being irradiated with the illumination light, and acquires an image (step S902).
  • the information processing apparatus 93 determines whether or not the number of times the calibration standard plate 95 has been photographed has reached the specified number of times (step S903).
  • the specified number of times is not limited as long as it is 2 times or more, but it can be, for example, 6 times.
  • the process proceeds to step S904, the calibration standard plate 95 is moved in the X-axis direction and / or the Y-axis direction (step S904), and then in step S902. Return and repeat the subsequent processing.
  • the range of the calibration standard plate 95 that fits in the field of view of the camera 92 becomes a range different from that at the time of the previous shooting, and the calibration images for the specified number of times of shooting the different range of the calibration standard plate 95 are acquired.
  • 3A to 3F show the relationship between the calibration standard plate 95 and the imaging ranges of the six calibration images.
  • the rectangle shown by the broken line in the figure is the shooting range.
  • H indicates dust and Y indicates dirt.
  • step S903 When it is determined in step S903 that the imaging has been performed a predetermined number of times, the information processing apparatus 93 extracts a feature amount from the acquired plurality of calibration images (step S905), and based on the extracted plurality of feature amounts. , The adjustment feature amount is calculated (step S906). Subsequently, the information processing apparatus 93 compares the calculated adjustment feature amount with the preset calibration reference value (step S907), and sets the lighting conditions as necessary based on the comparison result. (Step S908). Specifically, if there is a difference between the adjustment feature amount and the calibration reference value, the lighting conditions are reset by adjusting the current value of the lighting device 91 so as to calibrate the difference. .. This completes a series of routines for the calibration process of the optical system of the visual inspection device 9.
  • step S903 when the number of times of shooting is less than the specified number of times in step S903, the process returns to step S902 through step S904, but the process may return to step S901. That is, the lighting may be turned ON / OFF each time the image is taken.
  • the visual inspection device 9 Due to the configuration of the visual inspection device 9 according to the present application example as described above, even if some dust or dirt is generated on the calibration standard plate 95, the feature amount obtained from a plurality of calibration images can be obtained. Based on this, the adjustment feature amount of each pixel is calculated, so that the influence of dust and dirt can be reduced and highly accurate calibration can be performed. Therefore, it is possible to reduce the cost for ensuring and maintaining the cleanliness of the calibration standard plate 95.
  • FIG. 4 is a schematic view showing the hardware configuration of the substrate inspection device.
  • This substrate inspection device 1 is used for substrate appearance inspection (for example, inspection of solder joint state after reflow) in a surface mounting line.
  • the board inspection device 1 mainly includes a stage 10, a measurement unit 11, a control device 12, an information processing device 13, and a display device 14.
  • the measuring unit 11 includes a camera 110 and a lighting device 111.
  • the stage 10 is a mechanism for holding the substrate to be inspected and the calibration standard plate 15 and aligning them with the photographing position of the camera 110. As shown in FIG. 4, when the X-axis and the Y-axis are taken parallel to the stage 10 and the Z-axis is taken perpendicular to the stage 10, the stage 10 can translate at least two axes in the X direction and the Y direction.
  • the camera 110 is arranged so that the optical axis is parallel to the Z axis, and photographs the substrate on the stage 10 and the calibration standard plate 15 from vertically above.
  • the image data captured by the camera 110 is taken into the information processing device 13.
  • the camera 110 may have any field of view capable of capturing a desired imaging range, and any known technique can be adopted.
  • the lighting device 111 (111R, 111G, 111B) is a lighting means for irradiating a substrate and a standard plate 15 for calibration with illumination light of a different color (wavelength).
  • FIG. 4 schematically shows an XZ cross section of the illuminating device 111.
  • the illuminating device 111 is annular so that light of the same color can be illuminated from all directions (all directions around the Z axis). Or it has a dome shape.
  • FIG. 5 is a schematic plan view schematically showing the arrangement relationship of the light sources 111R, 111G, and 111B of the lighting device 111.
  • the lighting device 111 has a structure in which three annular light sources, a red light source 111R, a green light source 111G, and a blue light source 111B, are arranged concentrically around the optical axis of the camera 110.
  • the elevation angles and orientations of the light sources 111R, 111G, and 111B are adjusted so that the incident angles with respect to the substrate and the calibration standard plate 15 increase in the order of red light, green light, and blue light.
  • Such a lighting device 111 can be formed, for example, by arranging LEDs of each color R, G, and B in an annular shape on the outside of a dome-shaped diffuser plate.
  • the control device 12 is a control means for controlling the operation of the substrate inspection device 1, and is responsible for movement control of the stage 10, lighting and dimming control of the lighting device 111, shooting control of the camera 110, and the like.
  • the information processing apparatus 13 uses the image data captured from the camera 110 to acquire various measured values related to the calibration standard plate 15, calibrate the optical system of the measuring unit 11, and the state of the substrate to be inspected. It is a device that has a function of inspecting.
  • the display device 14 is a device that displays the measured values and inspection results obtained by the information processing device 13.
  • the information processing device 13 can be composed of, for example, a general-purpose computer having a CPU, RAM, a non-volatile storage device, and an input device. In FIG. 4, the control device 12, the information processing device 13, and the display device 14 are shown as separate blocks, but these may be configured by separate devices or may be configured by a single device. Good.
  • the calibration standard plate 15 has an area wider than the field of view of the camera, and is a white plate that reflects the illumination light from the illumination device 111 to the camera 110, whereby an image for calibration can be acquired. It is used by installing it on the stage 10 when performing calibration.
  • FIG. 6 is a block diagram showing a configuration of a functional module related to inspection processing provided by the information processing apparatus 13. These functional modules are realized by the CPU of the information processing device 13 reading and executing a program stored in the auxiliary storage device. However, all or part of the functions may be configured by a circuit such as an ASIC or FPGA.
  • the image acquisition unit 131 and the adjustment feature amount calculation unit 132 are the same as those of the visual inspection device 9 according to the application example for each function module of the calibration processing unit 133, detailed description thereof will be omitted.
  • the corrected image generation unit 134 is a function of generating a corrected image used for shading correction of the observed image. Using the adjustment feature amount calculated by the adjustment feature amount calculation unit 132, each pixel constituting the image generates a correction image composed of the adjustment feature amount.
  • the three-dimensional shape measurement unit 135 is a functional module that measures (restores) the three-dimensional shape of the substrate to be inspected from the two-dimensional image data.
  • An image obtained by the so-called color highlighting method is used to measure the three-dimensional shape of the substrate.
  • the color highlighting method irradiates a substrate with light of a plurality of colors (that is, wavelengths) at different incident angles, and the surface of the substrate has color characteristics according to its normal direction (that is, a normal reflection direction when viewed from a camera). This is a method of capturing the three-dimensional shape of the substrate surface as two-dimensional hue information by taking a picture with the color of the light source in the above appearing.
  • the inspection unit 136 measures various indexes related to the shape of the inspection board based on the three-dimensional shape data obtained by the three-dimensional shape measurement unit 135, and uses these measured values to inspect the state of the board. Is.
  • the storage unit 137 is a functional module that stores various programs, an inspection program that defines inspection items and conditions in the inspection unit 136, and a program for calibrating the visual inspection device 9.
  • the inspection program defines, for example, the position and size of the inspection target, the size of parts, the type of index to be measured, and the judgment reference value (threshold value and range for judging non-defective product and defective product) for each index. ..
  • the output processing unit 138 outputs a command for controlling the stage 10 and the measurement unit 11 to the control device 12, and outputs the measurement value and the inspection result obtained by the inspection unit 136 to the display device 14 and the like. It is a functional module to do.
  • FIG. 7 is a flowchart showing the flow of the inspection process.
  • step S101 a process of calibrating the optical system of the substrate inspection apparatus 1 is executed (step S101). Since the processing is the same as that of the visual inspection apparatus 9 according to the application example, detailed description thereof will be omitted, but a plurality of calibration image data (for example, one resolution each) obtained by photographing different parts of the calibration standard plate 15. As described above, about 10 image data having different positions in the shooting range) are acquired, the adjustment feature amount is calculated from the image, and calibration is performed based on this.
  • a plurality of calibration image data for example, one resolution each
  • the information processing apparatus 13 generates a correction image used for shading correction of the observed image in the correction image generation unit 134 (step S102). Specifically, as described above, using the adjustment feature amount calculated during the calibration process in step S101, each pixel constituting the image generates a correction image composed of the adjustment feature amount.
  • control device 12 controls the stage 10 according to the inspection program stored in the storage unit 137, and moves the stage 10 to the substrate measurement position (field of view of the camera 110) to be inspected (step S103). Then, the control device 12 turns on the lighting device 111 (step S104), and takes a picture with the camera 110 in a state of irradiating with red light, green light, and blue light (step S105). The obtained image data (observed image) is taken into the information processing device 13 by the image acquisition unit 131.
  • the information processing apparatus 13 performs shading correction on the observation image obtained in step S105 with reference to the correction image obtained in step S102 (step S106). Then, the three-dimensional shape measuring unit 135 restores the three-dimensional shape of the substrate from the observation image corrected in this way, and the inspection unit 136 uses the three-dimensional shape and the threshold value of the inspection program to determine the substrate. A visual inspection is carried out (step S107). When the inspection is completed, the display device 14 displays the result of the inspection (step S108) and ends a series of processes.
  • a predetermined feature amount is extracted from a plurality of images obtained by photographing different parts of the calibration standard plate 15, and based on the values of the extracted plurality of feature amounts. It is possible not only to calibrate the lighting conditions but also to perform shading correction of the image of the image to be inspected by using the adjustment feature amount calculated in the above.
  • the stage on which the calibration standard plate is placed is moved to acquire calibration images obtained by photographing a plurality of different parts, but by moving the photographing means in a horizontal plane, You may try to get this.
  • the calibration standard plate has an area wider than the field of view of the camera, but it is not always necessary, and the calibration standard plate has an area equal to or narrower than the field of view of the camera. It may be a thing. Even in this case, the purpose can be achieved by narrowing down the area for processing the captured image.
  • the standard plate for calibration is a white plate, but it does not have to be white and may be a transparent plate. Further, the calibration standard plate does not have to be a separate body from the visual inspection device, and may be a jig fixed within the imaging range of the camera.
  • the luminance value was extracted from each pixel of the acquired image, but for example, the average luminance value of each pixel in the region is taken as one unit of 100 ⁇ 100 pixels.
  • the value may be extracted as a "feature amount gradation value". According to such a method, the processing load can be reduced and the processing time can be shortened as compared with the case where the "adjustment feature amount" is calculated for each pixel.
  • One aspect of the present invention is a lighting means (91) that irradiates an object to be inspected with illumination light.
  • An inspection means (93) that inspects the object to be inspected by processing an image taken by the photographing means, and an inspection means (93).
  • a predetermined feature amount was extracted from a plurality of images of the calibration standard surface photographed by the photographing means in a state where the relative positions of the photographing means and the calibration standard surface in the horizontal direction were different, and the extracted features were extracted.
  • An adjustment feature amount calculation means (932) that calculates one adjustment feature amount based on the values of a plurality of feature amounts, and an adjustment feature amount calculation means (932).
  • the visual inspection device (9) performs calibration of the lighting means and / or correction processing of the captured image based on the adjustment feature amount. Is.
  • another aspect of the present invention is a method of calibrating an appearance inspection device that inspects the inspected object based on an image of the inspected object taken by irradiating the inspected object with illumination light.
  • An irradiation step (S901) of irradiating the calibration standard surface prepared for calibration with the illumination light and A photographing step (S902; S903; S904) for photographing a plurality of different ranges of the calibration standard surface irradiated with the illumination light, and
  • An extraction step (S905) for extracting a feature amount from a plurality of images of the standard surface for calibration taken in the photographing step, respectively.

Abstract

This appearance inspection device comprises an illumination means for emitting illumination light onto an object under inspection, a photography means for photographing the object under inspection and a calibration reference surface prepared for calibration, an inspection means for inspecting the object under inspection by processing an image photographed by the photography means, and an adjustment feature value calculation means for extracting prescribed feature values from a plurality of images of the calibration reference surface photographed by the photography means when the photography means and calibration reference surface were in different horizontal positional relationships and calculating a single adjustment feature value on the basis of the plurality of extracted feature values. The appearance inspection device uses the adjustment feature value to calibrate the illumination means and/or correct the photographed image.

Description

外観検査装置、外観検査装置の較正方法及びプログラムVisual inspection equipment, calibration method and program for visual inspection equipment
　本発明は、被検査物に照明光を照射して撮影された被検査物の画像に基づいて前記被検査物の検査を行う外観検査装置、及びその較正方法に関する。 The present invention relates to an appearance inspection device that inspects an inspected object based on an image of the inspected object taken by irradiating the inspected object with illumination light, and a calibration method thereof.
　従来から、被検査物に照明光を照射して撮影された被検査物の画像に基づいて、被検査物の検査を行う外観検査装置が知られている。 Conventionally, a visual inspection device that inspects an inspected object based on an image of the inspected object taken by irradiating the inspected object with illumination light has been known.
　例えば、特許文献１には、いわゆるカラーハイライト方式による鏡面物体の三次元形状計測と、いわゆる位相シフト法による拡散物体の三次元形状計測を組み合わせて、基板の外観検査を行う装置が開示されている。 For example, Patent Document 1 discloses an apparatus for inspecting the appearance of a substrate by combining three-dimensional shape measurement of a mirrored object by a so-called color highlighting method and three-dimensional shape measurement of a diffused object by a so-called phase shift method. There is.
　このような外観検査装置においては、照明光を照射する光源とカメラなどの撮影装置からなる光学系が、使用頻度や環境によって、経時的に本来の性能を発揮できなくなることがあるため、較正を実施することで、本来の性能を発揮できるように再調整して用いることが一般的である。 In such a visual inspection device, the optical system consisting of a light source that irradiates illumination light and an imaging device such as a camera may not be able to exhibit its original performance over time depending on the frequency of use and the environment. By implementing this, it is common to readjust and use it so that the original performance can be exhibited.
　上記のような較正は、次のようにして行われている。光源から光を治具（標準板など）に照射し、当該治具表面（以下、標準面ともいう）を撮影装置で撮影する（即ち、治具で反射した光を受光する）。そして、撮影装置で撮影した画像から輝度値を抽出し、その値が予め設定された基準値から外れている場合には、基準値に近づくように光源側の電流値を調節するなどして照明条件を調整して、再度照射、撮影を行う。このようにして、抽出される輝度値が基準値になるように調整を行う。 The above calibration is performed as follows. A jig (standard plate or the like) is irradiated with light from a light source, and the surface of the jig (hereinafter, also referred to as a standard surface) is photographed by a photographing device (that is, the light reflected by the jig is received). Then, the brightness value is extracted from the image taken by the photographing device, and if the value deviates from the preset reference value, the current value on the light source side is adjusted so as to approach the reference value for illumination. Adjust the conditions, irradiate and shoot again. In this way, adjustment is performed so that the extracted luminance value becomes a reference value.
特開２０１６－１１８５７号公報Japanese Unexamined Patent Publication No. 2016-11857
　ところで上記したような方法で較正を行う場合、標準面の清浄度が非常に重要になる。即ち、標準面にゴミ（埃など）や汚れが付着していた場合、撮影画像にはそれらが写り込み、当該箇所の輝度値に大きな変動が生じるため、正確な較正が実現できない。このことは、光学系の較正に限らず、例えば撮影画像のシェーディング補正など、治具表面の画像を用いて行う補正においても同様である。 By the way, when calibrating by the above method, the cleanliness of the standard surface is very important. That is, if dust (dust, etc.) or dirt adheres to the standard surface, they are reflected in the captured image, and the brightness value of the portion concerned fluctuates greatly, so that accurate calibration cannot be realized. This applies not only to the calibration of the optical system but also to the correction performed using the image of the jig surface, such as the shading correction of the captured image.
　このため、標準面のゴミなどの影響をなくすために、治具の状態を清浄に保つ、又は少なくとも較正の実行前に十分な清浄さを確保する必要があり、清浄度の確認に時間がかかるという問題があった。また、清浄度を確保するために治具のクリーニングを実施したとしても、クリーニング後から較正の実行までに清浄度を確保する必要があるうえ、装置に治具のクリーニング機構を設けた場合、装置のコストが高くなるという問題があった。 Therefore, in order to eliminate the influence of dust on the standard surface, it is necessary to keep the jig in a clean state, or at least ensure sufficient cleanliness before performing calibration, and it takes time to confirm the cleanliness. There was a problem. In addition, even if the jig is cleaned to ensure cleanliness, it is necessary to ensure cleanliness from the cleaning to the execution of calibration, and if the device is provided with a jig cleaning mechanism, the device There was a problem that the cost of the was high.
　本発明は、上記のような実情に鑑みてなされたものであり、較正用の標準面を撮影して行う外観検査装置の較正において、標準面の清浄度を厳密に保たずとも正確な較正を実現できる技術を提供することを目的とする。 The present invention has been made in view of the above circumstances, and in the calibration of a visual inspection apparatus performed by photographing a standard surface for calibration, accurate calibration is performed without strictly maintaining the cleanliness of the standard surface. The purpose is to provide a technology that can realize the above.
　前記の目的を達成するために、本発明は以下の構成を採用する。 In order to achieve the above object, the present invention adopts the following configuration.
　本発明に係る外観検査装置は、
　被検査物に対して、照明光を照射する照明手段と、
　前記被検査物、及び、較正のために準備される較正用標準面を撮影する撮影手段と、
　前記撮影手段によって撮影された画像を処理することによって、前記被検査物を検査する検査手段と、
　前記撮影手段と前記較正用標準面とに平行な方向における相対位置が異なった状態で前記撮影手段によって撮影される前記較正用標準面の複数の画像から所定の特徴量を抽出し、該抽出された複数の特徴量の値に基づいて、一の調整用特徴量を算出する、調整用特徴量算出手段と、
　を備え、
　前記調整用特徴量に基づいて、前記照明手段の較正、及び／又は、撮影された画像の補正処理、を行うことを特徴とする。 The visual inspection apparatus according to the present invention is
Lighting means that irradiates the object to be inspected with illumination light,
An imaging means for photographing the object to be inspected and a standard surface for calibration prepared for calibration.
An inspection means for inspecting the object to be inspected by processing an image taken by the photographing means, and an inspection means for inspecting the object to be inspected.
A predetermined feature amount is extracted from a plurality of images of the calibration standard surface photographed by the imaging means in a state where the relative positions in the direction parallel to the calibration standard surface are different from those of the imaging means, and the extracted features are extracted. An adjustment feature amount calculation means that calculates one adjustment feature amount based on the values of a plurality of feature amounts, and an adjustment feature amount calculation means.
With
Based on the adjustment feature amount, the lighting means is calibrated and / or the captured image is corrected.
　なお、上記の特徴量は例えば、輝度、明度、彩度などとすることができる。また、較正用標準面は、外観検査装置とは別体の標準板に設けられて、較正のために当該標準板が外観検査装置に配置されるのであってもよいし、外観検査装置に内蔵されたものでよい。 Note that the above feature quantities can be, for example, brightness, brightness, saturation, and the like. Further, the standard surface for calibration may be provided on a standard plate separate from the visual inspection device, and the standard plate may be arranged on the visual inspection device for calibration, or may be built in the visual inspection device. It may be the one that has been calibrated.
　上記のように、異なる範囲を撮影した複数の画像に基づいて調整用特徴量を求めることで、較正用の標準面にゴミ、汚れなどが存在する場合でも、これらの影響を抑止して、正確な較正を実現することが可能になる。 As described above, by obtaining the adjustment features based on multiple images taken in different ranges, even if dust, dirt, etc. are present on the standard surface for calibration, these effects can be suppressed and accurate. Calibration can be achieved.
　また、前記外観検査装置は、較正用標準板をさらに備え、前記較正用標準面は前記較正用標準板に設けられていてもよい。また、前記外観装置は、前記較正用標準板、及び／又は、前記撮影手段を、水平方向に移動させる、移動機構をさらに備えていてもよい。 Further, the visual inspection device may further include a calibration standard plate, and the calibration standard surface may be provided on the calibration standard plate. Further, the appearance device may further include a moving mechanism for moving the calibration standard plate and / or the photographing means in the horizontal direction.
　このような移動機構によって、撮影手段と較正用標準面とを互いに平行な方向において相対的に少しずつ移動させながら較正用標準面を撮影することで、容易に撮影手段と較正用標準面相対位置が異なった複数の画像を取得することができる。 With such a moving mechanism, the calibration standard surface is photographed while moving the imaging means and the calibration standard surface relatively little by little in a direction parallel to each other, so that the imaging means and the calibration standard surface can be easily positioned relative to each other. Can acquire multiple images with different values.
　また、前記調整用特徴量算出手段は、前記複数の画像の特徴量の階調値を、１×１画素以上の領域毎に抽出し、前記複数の画像から抽出された前記領域毎の前記階調値の最頻値を、前記領域における前記調整用特徴量とするようにしてもよい。なお、ここでいう「階調」は、画像の明暗のみを示すのでは無く、色彩における明度、彩度の程度も含む意味に用いる。また、「階調値」とは、例えば０～２５５の２５６段階のように画像データの画素が有する特徴量の階調そのものの値のみをいうのではなく、特徴量をある程度の値の幅を有するようにして何段階かにレベル分けし、段階毎の代表値として設定された値も含む意味に用いる。具体的には、例えば０～２５５の階調値を２５段階に分類し、各段階の代表値を、１０、２０、３０・・・とした場合の、その代表値を含む。また、前記領域が複数の画素からなる場合の特徴量の階調値は、当該領域を構成する各画素の階調値の平均値、最頻値、などとすることができる。また、領域毎の前記調整用特徴量とするのは、必ずしも複数の階調値の最頻値に限られるわけではなく、例えば複数の階調値の平均値又は中央値であってもよいし、最大値としてもよい。 Further, the adjustment feature amount calculating means extracts the gradation value of the feature amount of the plurality of images for each region of 1 × 1 pixel or more, and the floor of each region extracted from the plurality of images. The mode value of the adjustment price may be set as the adjustment feature amount in the region. The term "gradation" used here does not only indicate the lightness and darkness of the image, but also includes the lightness and the degree of saturation in the color. Further, the "gradation value" does not mean only the value of the gradation itself of the feature amount possessed by the pixel of the image data, for example, in 256 steps from 0 to 255, but the feature amount has a range of a certain value. It is used in the meaning of including the value set as the representative value for each stage by dividing the level into several stages so as to have it. Specifically, for example, when the gradation values from 0 to 255 are classified into 25 stages and the representative values of each stage are 10, 20, 30, ..., The representative values are included. Further, the gradation value of the feature amount when the region is composed of a plurality of pixels can be an average value, a mode value, or the like of the gradation values of each pixel constituting the region. Further, the adjustment feature amount for each region is not necessarily limited to the mode value of the plurality of gradation values, and may be, for example, the average value or the median value of the plurality of gradation values. , May be the maximum value.
　このようにすることで、較正用標準面のゴミ、汚れの影響を排除した、信頼度の高い調整用特徴量を得ることができる。 By doing so, it is possible to obtain a highly reliable adjustment feature amount that eliminates the influence of dust and dirt on the standard surface for calibration.
　また、前記外観検査装置は、前記照明光の照明条件を設定する照明条件設定手段、をさらに備え、前記照明条件設定手段は、前記調整用特徴量と、予め設定されている基準特徴量との比較に基づいて前記照明光の照明条件を設定することで、前記照明手段の較正を行うようにしてもよい。 Further, the visual inspection device further includes a lighting condition setting means for setting the lighting condition of the illumination light, and the lighting condition setting means has the adjustment feature amount and the preset reference feature amount. By setting the illumination conditions of the illumination light based on the comparison, the illumination means may be calibrated.
　このような構成により、外観検査装置の光学系に経時変化が生じた場合であっても、適切に照明条件を再設定して、被検査物の外観検査を実施することができる。 With such a configuration, even if the optical system of the visual inspection device changes with time, the lighting conditions can be appropriately reset and the visual inspection of the object to be inspected can be performed.
　また、前記外観検査装置は、前記調整用特徴量を用いて補正用画像を生成する、補正画像生成手段、をさらに備え、前記画像の補正処理は、前記検査手段が、前記補正用画像に基づいて、前記撮影手段によって撮影された画像のシェーディング補正を行うものであってもよい。 Further, the appearance inspection device further includes a correction image generation means for generating a correction image using the adjustment feature amount, and the correction processing of the image is performed by the inspection means based on the correction image. Therefore, the shading correction of the image captured by the photographing means may be performed.
　ここで、補正用画像は、例えば各画素の値を調整用特徴量とした画像とすることができ、このような画像データを撮影画像のシェーディング補正の基準とすることで、精度の高いシェーディング補正を行うことができる。なお、シェーディング補正は、撮影された画像における観察光学系の収差などを是正する補正である。 Here, the correction image can be, for example, an image in which the value of each pixel is used as the adjustment feature amount, and by using such image data as a reference for shading correction of the captured image, highly accurate shading correction can be performed. It can be performed. The shading correction is a correction for correcting aberrations of the observation optical system in the captured image.
　また、本発明に係る、外観検査装置の較正方法は、
　被検査物に照明光を照射して撮影された被検査物の画像に基づいて前記被検査物の検査を行う外観検査装置の較正を行う方法であって、
　較正のために準備される較正用標準面に前記照明光を照射する照射ステップと、
　前記照明光が照射された前記較正用標準面の異なる複数の範囲を撮影する撮影ステップと、
　前記撮影ステップで撮影された前記較正用標準面の複数の画像から、それぞれ特徴量を抽出する抽出ステップと、
　抽出された複数の特徴量の値に基づいて、一の調整用特徴量を算出する算出ステップと、
　前記調整量特徴量に基づいて、前記外観検査装置の較正を行う較正ステップと、
　を有することを特徴とする。 Further, the calibration method of the visual inspection apparatus according to the present invention is described.
It is a method of calibrating the visual inspection device that inspects the inspected object based on the image of the inspected object taken by irradiating the inspected object with illumination light.
An irradiation step of irradiating the calibration standard surface prepared for calibration with the illumination light, and
A photographing step of photographing a plurality of different ranges of the calibration standard surface irradiated with the illumination light, and
An extraction step of extracting features from a plurality of images of the standard surface for calibration taken in the shooting step, and
A calculation step for calculating one adjustment feature amount based on the extracted multiple feature amount values, and
A calibration step for calibrating the visual inspection device based on the adjustment amount feature amount, and
It is characterized by having.
　なお、ここでいう較正方法は光学系の較正方法のみでなく、画像処理における補正方法も含む意味に用いられる。 The calibration method referred to here is used to mean not only the calibration method of the optical system but also the correction method in image processing.
　また、前記撮影ステップでは、前記較正用標準面、及び／又は、撮影手段を前記較正標準面に平行な方向に移動させ、前記較正用標準面と前記撮影手段とに平行な方向における相対位置が異なる状態の前記較正用標準面の画像を、複数撮影してもよい。 Further, in the imaging step, the calibration standard surface and / or the imaging means is moved in a direction parallel to the calibration standard surface, and the relative position of the calibration standard surface and the imaging means in a direction parallel to the imaging means is set. A plurality of images of the standard surface for calibration in different states may be taken.
　また、前記抽出ステップでは、前記複数の画像の特徴量の階調値を、１×１画素以上の領域毎に抽出し、前記算出ステップでは、前記複数の画像から抽出された前記領域毎の前記階調値の最頻値を、前記領域における前記調整用特徴量としてもよい。 Further, in the extraction step, the gradation values of the feature amounts of the plurality of images are extracted for each region of 1 × 1 pixel or more, and in the calculation step, the said region for each of the plurality of images extracted. The mode value of the gradation value may be used as the adjustment feature amount in the region.
　また、前記較正ステップでは、前記調整用特徴量と、予め設定される基準特徴量とを比較することによって前記照明光の照明条件を較正してもよい。 Further, in the calibration step, the illumination conditions of the illumination light may be calibrated by comparing the adjustment feature amount with the preset reference feature amount.
　また、前記較正ステップでは、前記調整用特徴量を用いて補正用画像を生成し、前記補正用画像に基づいて、前記被検査物の画像のシェーディング補正を行ってもよい。 Further, in the calibration step, a correction image may be generated using the adjustment feature amount, and shading correction of the image of the object to be inspected may be performed based on the correction image.
　また、本発明は、上記の方法を外観検査装置に実行させるためのプログラム、そのようなプログラムを非一時的に記録したコンピュータ読取可能な記録媒体として捉えることもできる。 Further, the present invention can be regarded as a program for causing the visual inspection apparatus to execute the above method, and as a computer-readable recording medium in which such a program is recorded non-temporarily.
　また、上記構成及び処理の各々は技術的な矛盾が生じない限り互いに組み合わせて本発明を構成することができる。 Further, each of the above configurations and processes can be combined with each other to construct the present invention as long as no technical contradiction occurs.
　本発明によれば、較正用の標準面を撮影して行う外観検査装置の較正において、標準面の清浄度を厳密に保たずとも正確な較正を実現できる技術を提供することができる。 According to the present invention, it is possible to provide a technique capable of realizing accurate calibration without strictly maintaining the cleanliness of the standard surface in the calibration of the visual inspection apparatus performed by photographing the standard surface for calibration.
図１は、本発明の適用例に係る外観検査装置の構成を示す模式図である。FIG. 1 is a schematic view showing a configuration of a visual inspection apparatus according to an application example of the present invention. 図２は、本発明の適用例に係る外観検査装置の較正処理の流れを示すフローチャートである。FIG. 2 is a flowchart showing a flow of calibration processing of the visual inspection apparatus according to the application example of the present invention. 図３Ａは、較正用標準板と撮影範囲の関係を示す第１の図である。図３Ｂは、較正用標準板と撮影範囲の関係を示す第２の図である。図３Ｃは、較正用標準板と撮影範囲の関係を示す第３の図である。図３Ｄは、較正用標準板と撮影範囲の関係を示す第４の図である。図３Ｅは、較正用標準板と撮影範囲の関係を示す第５の図である。図３Ｆは、較正用標準板と撮影範囲の関係を示す第６の図である。FIG. 3A is a first diagram showing the relationship between the calibration standard plate and the photographing range. FIG. 3B is a second diagram showing the relationship between the calibration standard plate and the photographing range. FIG. 3C is a third diagram showing the relationship between the calibration standard plate and the photographing range. FIG. 3D is a fourth diagram showing the relationship between the calibration standard plate and the photographing range. FIG. 3E is a fifth diagram showing the relationship between the calibration standard plate and the photographing range. FIG. 3F is a sixth diagram showing the relationship between the calibration standard plate and the photographing range. 図４は、実施形態１に係る基板検査装置の構成を示す模式図である。FIG. 4 is a schematic view showing the configuration of the substrate inspection apparatus according to the first embodiment. 図５は、実施形態１に係る照明装置の構成を説明する平面図である。FIG. 5 is a plan view illustrating the configuration of the lighting device according to the first embodiment. 図６は、実施形態１に係る情報処理装置の機能を説明するブロック図である。FIG. 6 is a block diagram illustrating a function of the information processing apparatus according to the first embodiment. 図７は、実施形態１に係る基板検査装置の基板検査処理の流れを示すフローチャートである。FIG. 7 is a flowchart showing the flow of the substrate inspection process of the substrate inspection apparatus according to the first embodiment.
　以下、図面を参照して、本発明の実施例について説明する。 Hereinafter, examples of the present invention will be described with reference to the drawings.
　＜適用例＞
　（適用例の構成）
　本発明は例えば、図１に示すような外観検査装置に適用することができる。図１は本適用例に係る外観検査装置９の概略構成を示す概略模式図である。外観検査装置９は、検査対象物（図示せず）の画像を撮影し、当該画像に基づいて検査対象物を検査する装置であり、図１に示すように主な構成として照明手段としての照明装置９１、撮影手段としてのカメラ９２、検査手段としての情報処理装置９３（例えばコンピュータ）、移動機構９４を有している。 <Application example>
(Configuration of application example)
The present invention can be applied to, for example, a visual inspection apparatus as shown in FIG. FIG. 1 is a schematic schematic view showing a schematic configuration of an appearance inspection device 9 according to this application example. The visual inspection device 9 is a device that takes an image of an inspection object (not shown) and inspects the inspection object based on the image, and as shown in FIG. 1, the main configuration is illumination as a lighting means. It has a device 91, a camera 92 as an imaging means, an information processing device 93 (for example, a computer) as an inspection means, and a moving mechanism 94.
　照明装置９１は、検査対象物、及び較正用標準板９５に対して照明光を照射可能に構成されている。カメラ９２は、照明光が照射された状態の検査対象物、及び較正用標準板９５を撮影し、デジタル画像を出力する撮影手段である。なお、以下では、撮影手段によって撮影された検査対象物の画像を観測画像、較正用標準板９５の画像を較正用画像とも表記する。カメラ９２は例えば、光学系とイメージセンサを有して構成される。 The lighting device 91 is configured to be able to irradiate the inspection object and the calibration standard plate 95 with illumination light. The camera 92 is a photographing means for photographing an inspection object in a state of being irradiated with illumination light and a calibration standard plate 95 and outputting a digital image. In the following, the image of the inspection object taken by the photographing means will be referred to as an observation image, and the image of the calibration standard plate 95 will be referred to as a calibration image. The camera 92 includes, for example, an optical system and an image sensor.
　情報処理装置９３は、照明装置９１、カメラ９２及び移動機構９４の制御、カメラ９２から取り込まれた画像に対する処理、三次元形状計測などの機能を有しており、本発明における検査手段に該当する。情報処理装置９３は、ＣＰＵ（Central Processing Unit）、ＲＡＭ（Random Access Memory）、不揮発性の記憶装置（例えば、ハードディスクドライブ、フラッシュメモリなど）、入力装置（例えば、キーボード、マウス、タッチパネルなど）、表示装置（例えば、液晶ディスプレイなど）を備えるコンピュータにより構成することができる。 The information processing device 93 has functions such as control of a lighting device 91, a camera 92, and a moving mechanism 94, processing of an image captured from the camera 92, and three-dimensional shape measurement, and corresponds to the inspection means in the present invention. .. The information processing device 93 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a non-volatile storage device (for example, a hard disk drive, a flash memory, etc.), an input device (for example, a keyboard, a mouse, a touch panel, etc.), and a display. It can be configured by a computer equipped with a device (eg, a liquid crystal display, etc.).
　移動機構９４は、検査対象物、又は較正用標準板９５を載置するステージを兼ねており、モーター（図示せず）などのアクチュエータの駆動力によって、図１中に示すＸ軸方向、Ｙ軸方向に移動し、検査対象物、又は較正用標準板９５を載置している場合には、これらも移動させる。 The moving mechanism 94 also serves as a stage on which the inspection object or the standard plate 95 for calibration is placed, and is driven by an actuator such as a motor (not shown) in the X-axis direction and the Y-axis shown in FIG. Move in the direction, and if the inspection object or the calibration standard plate 95 is placed, move these as well.
　較正用標準板９５は、照明装置９１からの照明光をカメラ９２に反射させる、例えば白色の板部材である。較正用標準板９５の照明光反射面（即ちカメラ９２に撮影される面）が、本発明における較正用標準面に相当する。なお、較正用標準板９５は、外観検査装置９とは別体のものとしてもよいし、装置に組み込まれていてもよい。 The calibration standard plate 95 is, for example, a white plate member that reflects the illumination light from the illumination device 91 to the camera 92. The illumination light reflecting surface of the calibration standard plate 95 (that is, the surface imaged by the camera 92) corresponds to the calibration standard surface in the present invention. The calibration standard plate 95 may be a separate body from the visual inspection device 9, or may be incorporated in the device.
　以上のような構成を有する外観検査装置９において検査対象物の外観検査を行う際には、照明装置９１から照明光を照射された状態の検査対象物の画像をカメラ９２によって複数撮影し、撮影された画像を情報処理装置９３がカラーハイライト方式などの方法により画像処理することで、検査対象物を検査する。 When the appearance inspection device 9 having the above configuration performs the appearance inspection of the inspection object, a plurality of images of the inspection object in a state of being irradiated with the illumination light from the lighting device 91 are photographed by the camera 92 and photographed. The information processing apparatus 93 inspects the inspected object by performing image processing on the generated image by a method such as a color highlighting method.
　（情報処理装置）
　続いて、情報処理装置９３が有する機能について説明する。情報処理装置９３は、外観検査に関わる機能モジュールとして、画像取得部９３１、調整用特徴量算出部９３２、較正処理部９３３、照明条件設定部９３４、移動機構制御部９３５、を含んでいる。 (Information processing device)
Subsequently, the function of the information processing apparatus 93 will be described. The information processing device 93 includes an image acquisition unit 931, an adjustment feature amount calculation unit 932, a calibration processing unit 933, a lighting condition setting unit 934, and a movement mechanism control unit 935 as functional modules related to visual inspection.
　画像取得部９３１はカメラ９２から画像を取り込む機能であり、例えば、照明光が照射された状態の検査対象物の観測画像の他、較正用標準板９５を撮影した複数の較正用画像を取得する。例えば、本適用例では、較正用標準板９５の異なる箇所を撮影した６つの較正用画像データを取得する。 The image acquisition unit 931 is a function of capturing an image from the camera 92. For example, in addition to an observation image of an inspection object irradiated with illumination light, a plurality of calibration images obtained by photographing a calibration standard plate 95 are acquired. .. For example, in this application example, six calibration image data obtained by photographing different parts of the calibration standard plate 95 are acquired.
　調整用特徴量算出部９３２は、較正に用いる調整用特徴量を算出する機能である。例えば、本適用例では画像取得部９３１によって取得された６つの較正用画像データのそれぞれから、画像の各画素が有する特徴量（例えば輝度値）を抽出し、これに基づいて、画素毎に一の調整用特徴量を算出する。例えば、画素毎に、６つの画像データから抽出された６つの輝度値のデータの最頻値を求め、当該最頻値の値を、調整用特徴量とする。例えば、６つの較正用画像から得られたある画素の輝度値として、２００が３つ、１５０が２つ、１００が１つであった場合、当該画素の調整用特徴量を２００とする。この例では、正常な標準面の輝度値が２００で、輝度値が１５０、１００の箇所にはゴミや汚れなどの何らかの障害が生じているものと考えることができる。 The adjustment feature amount calculation unit 932 is a function for calculating the adjustment feature amount used for calibration. For example, in this application example, a feature amount (for example, a luminance value) possessed by each pixel of the image is extracted from each of the six calibration image data acquired by the image acquisition unit 931, and based on this, one pixel is extracted. Calculate the adjustment feature amount of. For example, for each pixel, the mode value of the data of the six luminance values extracted from the six image data is obtained, and the value of the mode value is used as the adjustment feature amount. For example, when the brightness values of a certain pixel obtained from the six calibration images are three for 200, two for 150, and one for 100, the adjustment feature amount of the pixel is set to 200. In this example, it can be considered that some obstacles such as dust and dirt have occurred in the places where the normal standard surface has a brightness value of 200 and the brightness values are 150 and 100.
　較正処理部９３３は、調整用特徴量算出部９３２によって算出された調整用特徴量と、予め設定されている較正用基準値を比較し較正する機能であり、両者の値の差の有無、いずれの値が高い値か、その程度、などを求める。 The calibration processing unit 933 is a function of comparing and calibrating the adjustment feature amount calculated by the adjustment feature amount calculation unit 932 with the preset calibration reference value, and whether or not there is a difference between the two values. Find out whether the value of is high or its degree.
　照明条件設定部９３４は、照明装置９１による照明条件の設定を行う機能であり、較正処理部９３３によって求められた結果に基づいて、較正用画像から抽出される調整用特徴量が較正用基準値と適合するように、照明装置９１の電流値を変更するなど処理を行う。 The illumination condition setting unit 934 is a function of setting the illumination condition by the illumination device 91, and the adjustment feature amount extracted from the calibration image based on the result obtained by the calibration processing unit 933 is the calibration reference value. Processing such as changing the current value of the lighting device 91 is performed so as to match with.
　移動機構制御部９３５は、移動機構９４の駆動を制御する機構であり、ユーザーの入力、予め定められたプログラム、などに基づいて移動機構９４を移動させるためのアクチュエータの制御などを行う。 The movement mechanism control unit 935 is a mechanism that controls the drive of the movement mechanism 94, and controls an actuator for moving the movement mechanism 94 based on a user's input, a predetermined program, or the like.
　（較正処理の流れ）
　次に、図２を参照して、本適用例において較正用標準板９５を用いて光学系の較正処理を行う手順について説明する。まず、情報処理装置９３は照明装置９１を制御し、較正用標準板に対し照明光を照射する（ステップＳ９０１）。次に、情報処理装置９３は、カメラ９２を制御して、照明光が照射されている状態の較正用標準板９５を撮影し、画像を取得する（ステップＳ９０２）。 (Flow of calibration process)
Next, with reference to FIG. 2, a procedure for calibrating the optical system using the calibration standard plate 95 in this application example will be described. First, the information processing device 93 controls the lighting device 91 and irradiates the calibration standard plate with the lighting light (step S901). Next, the information processing device 93 controls the camera 92 to take a picture of the calibration standard plate 95 in a state of being irradiated with the illumination light, and acquires an image (step S902).
　次に、情報処理装置９３は較正用標準板９５を撮影した回数が規定回数に達しているか否かを判定する（ステップＳ９０３）。規定回数は２回以上であれば限定されないが、例えば６回とすることができる。ここで、撮影回数が規定回数に達していない場合には、ステップＳ９０４に進み、較正用標準板９５を、Ｘ軸方向及び／又はＹ軸方向に移動させてから（ステップＳ９０４）、ステップＳ９０２に戻り、その後の処理を繰り返す。これによって、カメラ９２の視野に収まる較正用標準板９５の範囲が、前回の撮影時とは異なる範囲となり、較正用標準板９５の異なる範囲を撮影した規定回数分の較正用画像を取得することができる。図３Ａ～図３Ｆに較正用標準板９５と、６つの較正用画像の撮影範囲との関係を示す。図中の破線で示された矩形が撮影範囲である。なお、図中のＨはゴミを、Ｙは汚れを、それぞれ示している。 Next, the information processing apparatus 93 determines whether or not the number of times the calibration standard plate 95 has been photographed has reached the specified number of times (step S903). The specified number of times is not limited as long as it is 2 times or more, but it can be, for example, 6 times. Here, if the number of times of photographing has not reached the specified number of times, the process proceeds to step S904, the calibration standard plate 95 is moved in the X-axis direction and / or the Y-axis direction (step S904), and then in step S902. Return and repeat the subsequent processing. As a result, the range of the calibration standard plate 95 that fits in the field of view of the camera 92 becomes a range different from that at the time of the previous shooting, and the calibration images for the specified number of times of shooting the different range of the calibration standard plate 95 are acquired. Can be done. 3A to 3F show the relationship between the calibration standard plate 95 and the imaging ranges of the six calibration images. The rectangle shown by the broken line in the figure is the shooting range. In the figure, H indicates dust and Y indicates dirt.
　ステップＳ９０３で、規定回数撮影を行ったと判定された場合には、情報処理装置９３は、取得した複数の較正用画像から特徴量を抽出し（ステップＳ９０５）、抽出した複数の特徴量に基づいて、調整用特徴量を算出する（ステップＳ９０６）。続けて、情報処理装置９３は、算出された調整用特徴量と、予め設定されている較正用基準値を比較し（ステップＳ９０７）、当該比較結果に基づき、必要に応じて照明条件の設定を行う（ステップＳ９０８）。具体的には、調整用特徴量と較正用基準値とに差がある場合には、当該差を較正するように照明装置９１の電流値の調節を行うなどして、照明条件を再設定する。これによって外観検査装置９の光学系の較正処理の一連のルーテインは終了する。 When it is determined in step S903 that the imaging has been performed a predetermined number of times, the information processing apparatus 93 extracts a feature amount from the acquired plurality of calibration images (step S905), and based on the extracted plurality of feature amounts. , The adjustment feature amount is calculated (step S906). Subsequently, the information processing apparatus 93 compares the calculated adjustment feature amount with the preset calibration reference value (step S907), and sets the lighting conditions as necessary based on the comparison result. (Step S908). Specifically, if there is a difference between the adjustment feature amount and the calibration reference value, the lighting conditions are reset by adjusting the current value of the lighting device 91 so as to calibrate the difference. .. This completes a series of routines for the calibration process of the optical system of the visual inspection device 9.
　なお、上記において、ステップＳ９０３で撮影回数が規定回数に満たない場合は、ステップＳ９０４を経て、ステップＳ９０２に戻るようにしていたが、ステップＳ９０１に戻ってもよい。即ち、撮影の度に、照明のＯＮ／ＯＦＦを行ってもよい。 In the above, when the number of times of shooting is less than the specified number of times in step S903, the process returns to step S902 through step S904, but the process may return to step S901. That is, the lighting may be turned ON / OFF each time the image is taken.
　以上のような、本適用例に係る外観検査装置９の構成により、較正用標準板９５に多少のゴミや汚れが生じていた場合であっても、複数の較正用画像から得られる特徴量に基づいて、各画素の調整用特徴量を算出するため、ゴミや汚れの影響を低減して精度の高い較正を実施することができる。このため、較正用標準板９５の清浄度の確保、維持のためのコストを低減することができる。 Due to the configuration of the visual inspection device 9 according to the present application example as described above, even if some dust or dirt is generated on the calibration standard plate 95, the feature amount obtained from a plurality of calibration images can be obtained. Based on this, the adjustment feature amount of each pixel is calculated, so that the influence of dust and dirt can be reduced and highly accurate calibration can be performed. Therefore, it is possible to reduce the cost for ensuring and maintaining the cleanliness of the calibration standard plate 95.
　＜実施形態１＞
　次に、本発明を実施するための形態の他の例である基板検査装置１について説明する。ただし、この実施形態に記載されている構成部品の寸法、材質、形状、その相対配置などは、特に記載がない限りは、この発明の範囲をそれらのみに限定する趣旨のものではない。 <Embodiment 1>
Next, the substrate inspection apparatus 1 which is another example of the embodiment for carrying out the present invention will be described. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention to those.
　（基板検査装置のハードウェア構成）
　図４を参照して、本発明の実施形態に係る基板検査装置の全体構成について説明する。図４は基板検査装置のハードウェア構成を示す模式図である。この基板検査装置１は、表面実装ラインにおける基板外観検査（例えば、リフロー後のはんだ接合状態の検査など）に利用される。 (Hardware configuration of board inspection equipment)
The overall configuration of the substrate inspection apparatus according to the embodiment of the present invention will be described with reference to FIG. FIG. 4 is a schematic view showing the hardware configuration of the substrate inspection device. This substrate inspection device 1 is used for substrate appearance inspection (for example, inspection of solder joint state after reflow) in a surface mounting line.
　基板検査装置１は、主な構成として、ステージ１０、計測ユニット１１、制御装置１２、情報処理装置１３、表示装置１４を備える。計測ユニット１１は、カメラ１１０、照明装置１１１、を有している。 The board inspection device 1 mainly includes a stage 10, a measurement unit 11, a control device 12, an information processing device 13, and a display device 14. The measuring unit 11 includes a camera 110 and a lighting device 111.
　ステージ１０は、検査対象となる基板、較正用標準板１５を保持し、カメラ１１０の撮影位置に位置合わせするための機構である。図４に示すようにステージ１０に平行にＸ軸とＹ軸をとり、ステージ１０と垂直にＺ軸をとった場合、ステージ１０は少なくともＸ方向とＹ方向の２軸の並進が可能である。カメラ１１０は、光軸がＺ軸と平行になるように配置されており、ステージ１０上の基板、較正用標準板１５を鉛直上方から撮影する。カメラ１１０で撮影された画像データは情報処理装置１３に取り込まれる。 The stage 10 is a mechanism for holding the substrate to be inspected and the calibration standard plate 15 and aligning them with the photographing position of the camera 110. As shown in FIG. 4, when the X-axis and the Y-axis are taken parallel to the stage 10 and the Z-axis is taken perpendicular to the stage 10, the stage 10 can translate at least two axes in the X direction and the Y direction. The camera 110 is arranged so that the optical axis is parallel to the Z axis, and photographs the substrate on the stage 10 and the calibration standard plate 15 from vertically above. The image data captured by the camera 110 is taken into the information processing device 13.
　カメラ１１０は、所望の撮影範囲を撮影可能な視野を有するものであればよく、任意の公知技術を採用することができる。 The camera 110 may have any field of view capable of capturing a desired imaging range, and any known technique can be adopted.
　照明装置１１１（１１１Ｒ，１１１Ｇ，１１１Ｂ）は、基板、較正用標準板１５に対し異なる色（波長）の照明光を照射する照明手段である。図４は照明装置１１１のＸＺ断面を模式的に示したものであり、実際には、同じ色の光を全方位（Ｚ軸回りの全方向）から照明可能なように照明装置１１１は円環状又はドーム形状を呈している。 The lighting device 111 (111R, 111G, 111B) is a lighting means for irradiating a substrate and a standard plate 15 for calibration with illumination light of a different color (wavelength). FIG. 4 schematically shows an XZ cross section of the illuminating device 111. In reality, the illuminating device 111 is annular so that light of the same color can be illuminated from all directions (all directions around the Z axis). Or it has a dome shape.
　図５は、照明装置１１１の各光源１１１Ｒ、１１１Ｇ、１１１Ｂの配置関係を模式的に示す平面概略図である。照明装置１１１は、赤色光源１１１Ｒ、緑色光源１１１Ｇ、青色光源１１１Ｂの３つの円環状の光源を、カメラ１１０の光軸を中心として同心円状に配置した構造を有している。各光源１１１Ｒ、１１１Ｇ、１１１Ｂは、赤色光、緑色光、青色光の順に、基板、較正用標準板１５に対する入射角が大きくなるよう、仰角及び向きが調整されている。このような照明装置１１１は、例えば、ドーム形状の拡散板の外側にＲ、Ｇ、Ｂ各色のＬＥＤを円環状に配列することで形成できる。 FIG. 5 is a schematic plan view schematically showing the arrangement relationship of the light sources 111R, 111G, and 111B of the lighting device 111. The lighting device 111 has a structure in which three annular light sources, a red light source 111R, a green light source 111G, and a blue light source 111B, are arranged concentrically around the optical axis of the camera 110. The elevation angles and orientations of the light sources 111R, 111G, and 111B are adjusted so that the incident angles with respect to the substrate and the calibration standard plate 15 increase in the order of red light, green light, and blue light. Such a lighting device 111 can be formed, for example, by arranging LEDs of each color R, G, and B in an annular shape on the outside of a dome-shaped diffuser plate.
　制御装置１２は、基板検査装置１の動作を制御する制御手段であり、ステージ１０の移動制御、照明装置１１１の点灯及び調光制御、カメラ１１０の撮影制御などを担っている。 The control device 12 is a control means for controlling the operation of the substrate inspection device 1, and is responsible for movement control of the stage 10, lighting and dimming control of the lighting device 111, shooting control of the camera 110, and the like.
　情報処理装置１３は、カメラ１１０から取り込まれた画像データを用いて、較正用標準板１５に関する各種の計測値を取得したり、計測ユニット１１の光学系の較正を行ったり、検査対象基板の状態を検査したりする機能を有する装置である。表示装置１４は、情報処理装置１３で得られた計測値や検査結果を表示する装置である。情報処理装置１３は、例えば、ＣＰＵ、ＲＡＭ、不揮発性の記憶装置、入力装置を有する汎用のコンピュータにより構成することができる。なお、図４では、制御装置１２と情報処理装置１３と表示装置１４を別のブロックで示したが、これらは別体の装置で構成してもよいし、単一の装置で構成してもよい。 The information processing apparatus 13 uses the image data captured from the camera 110 to acquire various measured values related to the calibration standard plate 15, calibrate the optical system of the measuring unit 11, and the state of the substrate to be inspected. It is a device that has a function of inspecting. The display device 14 is a device that displays the measured values and inspection results obtained by the information processing device 13. The information processing device 13 can be composed of, for example, a general-purpose computer having a CPU, RAM, a non-volatile storage device, and an input device. In FIG. 4, the control device 12, the information processing device 13, and the display device 14 are shown as separate blocks, but these may be configured by separate devices or may be configured by a single device. Good.
　較正用標準板１５は、カメラの視野よりも広い面積を有しており、照明装置１１１からの照明光をカメラ１１０に反射させ、これによって較正用の画像を取得可能にする白色板であり、較正を行う際に、ステージ１０上に設置して用いられる。 The calibration standard plate 15 has an area wider than the field of view of the camera, and is a white plate that reflects the illumination light from the illumination device 111 to the camera 110, whereby an image for calibration can be acquired. It is used by installing it on the stage 10 when performing calibration.
　（機能構成）
　図６は、情報処理装置１３が提供する検査処理に関わる機能モジュールの構成を示すブロック図である。これらの機能モジュールは、情報処理装置１３のＣＰＵが補助記憶装置に格納されたプログラムを読み込み実行することにより実現されるものである。ただし、全部又は一部の機能をＡＳＩＣやＦＰＧＡなどの回路で構成してもよい。 (Functional configuration)
FIG. 6 is a block diagram showing a configuration of a functional module related to inspection processing provided by the information processing apparatus 13. These functional modules are realized by the CPU of the information processing device 13 reading and executing a program stored in the auxiliary storage device. However, all or part of the functions may be configured by a circuit such as an ASIC or FPGA.
　なお、画像取得部１３１、調整用特徴量算出部１３２は、較正処理部１３３の各機能モジュールについては、適用例に係る外観検査装置９のものと同様であるため、詳細な説明は省略する。 Since the image acquisition unit 131 and the adjustment feature amount calculation unit 132 are the same as those of the visual inspection device 9 according to the application example for each function module of the calibration processing unit 133, detailed description thereof will be omitted.
　補正画像生成部１３４は、観測画像のシェーディング補正に用いる補正画像を生成する機能である。調整用特徴量算出部１３２によって算出された調整用特徴量を用いて、画像を構成する各画素が調整用特徴量からなる補正画像を生成する。 The corrected image generation unit 134 is a function of generating a corrected image used for shading correction of the observed image. Using the adjustment feature amount calculated by the adjustment feature amount calculation unit 132, each pixel constituting the image generates a correction image composed of the adjustment feature amount.
　三次元形状計測部１３５は、二次元の画像データから検査対象基板の三次元形状を計測（復元）する機能モジュールである。基板の三次元形状の計測には、いわゆるカラーハイライト方式で得られる画像を利用する。カラーハイライト方式とは、複数の色（即ち、波長）の光を互いに異なる入射角で基板に照射し、基板表面にその法線方向に応じた色特徴（即ち、カメラから見て正反射方向にある光源の色）が現れるようにした状態で撮影を行うことにより、基板表面の三次元形状を二次元の色相情報として捉える方法である。画像の中から、Ｒ、Ｇ、Ｂの光源色が現れている領域のみを抽出して、Ｒ、Ｇ、Ｂの各領域の形状、幅、順番に基づいて、基板の三次元形状を復元することができる。なお、三次元形状の復元には公知の手法を用いることができるため、ここでは詳しい説明を省略する。 The three-dimensional shape measurement unit 135 is a functional module that measures (restores) the three-dimensional shape of the substrate to be inspected from the two-dimensional image data. An image obtained by the so-called color highlighting method is used to measure the three-dimensional shape of the substrate. The color highlighting method irradiates a substrate with light of a plurality of colors (that is, wavelengths) at different incident angles, and the surface of the substrate has color characteristics according to its normal direction (that is, a normal reflection direction when viewed from a camera). This is a method of capturing the three-dimensional shape of the substrate surface as two-dimensional hue information by taking a picture with the color of the light source in the above appearing. Only the regions where the light source colors of R, G, and B appear are extracted from the image, and the three-dimensional shape of the substrate is restored based on the shape, width, and order of each region of R, G, and B. be able to. Since a known method can be used for the restoration of the three-dimensional shape, detailed description thereof will be omitted here.
　検査部１３６は、三次元形状計測部１３５で得られた三次元形状データを基に、検査基板の形状に関わる各種指標を計測し、これらの計測値を用いて基板の状態を検査する機能モジュールである。 The inspection unit 136 measures various indexes related to the shape of the inspection board based on the three-dimensional shape data obtained by the three-dimensional shape measurement unit 135, and uses these measured values to inspect the state of the board. Is.
　記憶部１３７は、各種のプログラムや、検査部１３６における検査の項目、条件などを定義した検査プログラムの他、外観検査装置９の較正のためのプログラムなど、各種情報を格納する機能モジュールである。検査プログラムには、例えば、検査対象の位置及びサイズ、部品のサイズ、計測する指標の種類、指標ごとの判定基準値（良品と不良品を判定するための閾値や値域）などが定義されている。 The storage unit 137 is a functional module that stores various programs, an inspection program that defines inspection items and conditions in the inspection unit 136, and a program for calibrating the visual inspection device 9. The inspection program defines, for example, the position and size of the inspection target, the size of parts, the type of index to be measured, and the judgment reference value (threshold value and range for judging non-defective product and defective product) for each index. ..
　出力処理部１３８は、ステージ１０、計測ユニット１１を制御するための指令を、制御装置１２に出力したり、検査部１３６で得られた計測値や検査結果などを表示装置１４などへ出力したりする機能モジュールである。 The output processing unit 138 outputs a command for controlling the stage 10 and the measurement unit 11 to the control device 12, and outputs the measurement value and the inspection result obtained by the inspection unit 136 to the display device 14 and the like. It is a functional module to do.
　（検査処理の流れ）
　次に、図７を用いて、基板検査装置１で行われる検査処理の流れを説明する。図７は、検査処理の流れを示すフローチャートである。 (Flow of inspection process)
Next, the flow of the inspection process performed by the substrate inspection apparatus 1 will be described with reference to FIG. 7. FIG. 7 is a flowchart showing the flow of the inspection process.
　まず、基板の検査に先だって、基板検査装置１の光学系を較正する処理を実行する（ステップＳ１０１）。当該処理は適用例に係る外観検査装置９のものと同様であるため、詳細な説明は省略するが、較正用標準板１５の異なる箇所を撮影した複数の較正用画像データ（例えば、それぞれ一分解能以上、撮影範囲の位置が異なる画像データを１０個程度）を取得し、当該画像から調整用特徴量を算出し、これに基づいて較正を実施する。 First, prior to the inspection of the substrate, a process of calibrating the optical system of the substrate inspection apparatus 1 is executed (step S101). Since the processing is the same as that of the visual inspection apparatus 9 according to the application example, detailed description thereof will be omitted, but a plurality of calibration image data (for example, one resolution each) obtained by photographing different parts of the calibration standard plate 15. As described above, about 10 image data having different positions in the shooting range) are acquired, the adjustment feature amount is calculated from the image, and calibration is performed based on this.
　次に、情報処理装置１３は、補正画像生成部１３４において、観測画像のシェーディング補正に用いる補正用画像を生成する（ステップＳ１０２）。具体的には、上述したように、ステップＳ１０１の較正処理の際に算出した調整用特徴量を用いて、画像を構成する各画素が調整用特徴量からなる補正画像を生成する。 Next, the information processing apparatus 13 generates a correction image used for shading correction of the observed image in the correction image generation unit 134 (step S102). Specifically, as described above, using the adjustment feature amount calculated during the calibration process in step S101, each pixel constituting the image generates a correction image composed of the adjustment feature amount.
　次に、制御装置１２が記憶部１３７に記憶されている検査プログラムに従ってステージ１０を制御し、検査対象の基板計測位置（カメラ１１０の視野）に移動させる（ステップＳ１０３）。そして、制御装置１２が照明装置１１１を点灯し（ステップＳ１０４）、赤色光、緑色光、青色光を照射した状態でカメラ１１０で撮影を行う（ステップＳ１０５）。得られた画像データ（観測画像）は、画像取得部１３１により情報処理装置１３に取り込まれる。 Next, the control device 12 controls the stage 10 according to the inspection program stored in the storage unit 137, and moves the stage 10 to the substrate measurement position (field of view of the camera 110) to be inspected (step S103). Then, the control device 12 turns on the lighting device 111 (step S104), and takes a picture with the camera 110 in a state of irradiating with red light, green light, and blue light (step S105). The obtained image data (observed image) is taken into the information processing device 13 by the image acquisition unit 131.
　次に、情報処理装置１３は、ステップＳ１０２で得られた補正用画像を基準として、ステップＳ１０５で得られた観測画像をシェーディング補正する（ステップＳ１０６）。そして、三次元形状計測部１３５は、このようにして補正された観測画像から、基板の三次元形状を復元し、検査部１３６が、当該三次元形状と、検査プログラムの閾値とによって、基板の外観検査を実施する（ステップＳ１０７）。検査が終了すると、表示装置１４は、検査の結果を表示し（ステップＳ１０８）、一連の処理を終了する。 Next, the information processing apparatus 13 performs shading correction on the observation image obtained in step S105 with reference to the correction image obtained in step S102 (step S106). Then, the three-dimensional shape measuring unit 135 restores the three-dimensional shape of the substrate from the observation image corrected in this way, and the inspection unit 136 uses the three-dimensional shape and the threshold value of the inspection program to determine the substrate. A visual inspection is carried out (step S107). When the inspection is completed, the display device 14 displays the result of the inspection (step S108) and ends a series of processes.
　以上述べた本実施形態の基板検査装置によれば、較正用標準板１５の異なる箇所を撮影した複数の画像から、所定の特徴量を抽出し、該抽出された複数の特徴量の値に基づいて算出される調整用特徴量を用いて、照明条件の較正を行うだけでなく、被検査物を撮影した画像のシェーディング補正も実施することができる。 According to the substrate inspection apparatus of the present embodiment described above, a predetermined feature amount is extracted from a plurality of images obtained by photographing different parts of the calibration standard plate 15, and based on the values of the extracted plurality of feature amounts. It is possible not only to calibrate the lighting conditions but also to perform shading correction of the image of the image to be inspected by using the adjustment feature amount calculated in the above.
　＜その他＞
　上記各実施形態は、本発明を例示的に説明するものに過ぎず、本発明は上記の具体的な形態には限定されない。本発明はその技術的思想の範囲内で種々の変形が可能である。例えば、上記の実施形態においては、カラーハイライト方式を用いる基板検査装置に本発明が適用されていたが、他の方式による基板検査装置、透過光及び／又は反射光によってシート状の被検査物を検査するシート外観検査装置などに、本発明を適用することもできる。 <Others>
Each of the above embodiments is merely an example of the present invention, and the present invention is not limited to the above specific embodiment. The present invention can be modified in various ways within the scope of its technical idea. For example, in the above embodiment, the present invention has been applied to a substrate inspection device using a color highlighting method, but a substrate inspection device using another method, a sheet-like object to be inspected by transmitted light and / or reflected light. The present invention can also be applied to a sheet appearance inspection device or the like for inspecting.
　また、上記の各例では、較正用標準板を載置するステージを移動させて、複数の異なる箇所を撮影した較正用画像を取得していたが、撮影手段を水平面内で移動させることにより、これを取得するようにしてもよい。 Further, in each of the above examples, the stage on which the calibration standard plate is placed is moved to acquire calibration images obtained by photographing a plurality of different parts, but by moving the photographing means in a horizontal plane, You may try to get this.
　また、上記の実施形態では較正用標準板は、カメラの視野よりも広い面積を有するものであったが、必ずしもその必要はなく、較正用標準板はカメラの視野と同等、又は狭い面積を有するものであってもよい。この場合でも、撮影画像に対して処理を行う領域を絞り込むことで目的を達成することができる。 Further, in the above embodiment, the calibration standard plate has an area wider than the field of view of the camera, but it is not always necessary, and the calibration standard plate has an area equal to or narrower than the field of view of the camera. It may be a thing. Even in this case, the purpose can be achieved by narrowing down the area for processing the captured image.
　また、上記の実施形態においては、較正用標準板は白色板であったが、白色である必要は無く、透明板であってもよい。また、較正用標準板は外観検査装置と別体である必要は無く、カメラの撮影範囲内に固定された治具であってもよい。 Further, in the above embodiment, the standard plate for calibration is a white plate, but it does not have to be white and may be a transparent plate. Further, the calibration standard plate does not have to be a separate body from the visual inspection device, and may be a jig fixed within the imaging range of the camera.
　また、上記の各例においては、輝度値は取得された画像の各画素から抽出されていたが、例えば１００×１００画素の領域を一つの単位として、当該領域内の各画素の輝度値の平均値を、「特徴量の階調値」として抽出するのであってもよい。このような手法によれば、一つ一つの画素毎に「調整用特徴量」を算出する場合に比べ、処理の負荷を軽減し、処理時間を短縮させることができる。 Further, in each of the above examples, the luminance value was extracted from each pixel of the acquired image, but for example, the average luminance value of each pixel in the region is taken as one unit of 100 × 100 pixels. The value may be extracted as a "feature amount gradation value". According to such a method, the processing load can be reduced and the processing time can be shortened as compared with the case where the "adjustment feature amount" is calculated for each pixel.
　本発明の一の態様は、被検査物に対して、照明光を照射する照明手段（９１）と、
　前記被検査物、及び、較正のために準備される較正用標準面を撮影する撮影手段（９２）と、
　前記撮影手段によって撮影された画像を処理することによって、前記被検査物を検査する検査手段（９３）と、
　前記撮影手段と前記較正用標準面との水平方向における相対位置が異なった状態で前記撮影手段によって撮影される前記較正用標準面の複数の画像から所定の特徴量を抽出し、該抽出された複数の特徴量の値に基づいて、一の調整用特徴量を算出する、調整用特徴量算出手段（９３２）と、
　を備え、
　前記調整用特徴量に基づいて、前記照明手段の較正、及び／又は、撮影された画像の補正処理、を行う外観検査装置（９）、である。
である。 One aspect of the present invention is a lighting means (91) that irradiates an object to be inspected with illumination light.
An imaging means (92) for photographing the object to be inspected and a standard surface for calibration prepared for calibration, and
An inspection means (93) that inspects the object to be inspected by processing an image taken by the photographing means, and an inspection means (93).
A predetermined feature amount was extracted from a plurality of images of the calibration standard surface photographed by the photographing means in a state where the relative positions of the photographing means and the calibration standard surface in the horizontal direction were different, and the extracted features were extracted. An adjustment feature amount calculation means (932) that calculates one adjustment feature amount based on the values of a plurality of feature amounts, and an adjustment feature amount calculation means (932).
With
The visual inspection device (9) performs calibration of the lighting means and / or correction processing of the captured image based on the adjustment feature amount.
Is.
　また、本発明の他の一の態様は、被検査物に照明光を照射して撮影された被検査物の画像に基づいて前記被検査物の検査を行う外観検査装置の較正を行う方法であって、
　較正のために準備される較正用標準面に前記照明光を照射する照射ステップ（Ｓ９０１）と、
　前記照明光が照射された前記較正用標準面の異なる複数の範囲を撮影する撮影ステップ（Ｓ９０２；Ｓ９０３；Ｓ９０４）と、
　前記撮影ステップで撮影された前記較正用標準面の複数の画像から、それぞれ特徴量を抽出する抽出ステップ（Ｓ９０５）と、
　抽出された複数の特徴量の値に基づいて、一の調整用特徴量を算出する算出ステップ（Ｓ９０６）と、
　前記調整量特徴量に基づいて、前記外観検査装置の較正を行う較正ステップ（Ｓ９０７；Ｓ９０８）と、
　を有することを特徴とする、外観検査装置の較正方法、である。 Further, another aspect of the present invention is a method of calibrating an appearance inspection device that inspects the inspected object based on an image of the inspected object taken by irradiating the inspected object with illumination light. There,
An irradiation step (S901) of irradiating the calibration standard surface prepared for calibration with the illumination light, and
A photographing step (S902; S903; S904) for photographing a plurality of different ranges of the calibration standard surface irradiated with the illumination light, and
An extraction step (S905) for extracting a feature amount from a plurality of images of the standard surface for calibration taken in the photographing step, respectively.
A calculation step (S906) for calculating one adjustment feature amount based on the extracted values of the plurality of feature amounts, and
A calibration step (S907; S908) for calibrating the visual inspection apparatus based on the adjusted feature amount, and
It is a calibration method of a visual inspection apparatus, characterized in that it has.
　１・・・基板検査装置
　９・・・外観検査装置
　１０・・・ステージ
　１１・・・計測ユニット
　１１０、９２・・・カメラ
　１１１、９１・・・照明装置
　１２・・・制御装置
　１３、９３・・・情報処理装置
　１４・・・表示装置
　１５、９５・・・較正用標準板
　９４・・・移動機構
　Ｈ・・・ゴミ
　Ｙ・・・汚れ
  1 ... Board inspection device 9 ... Appearance inspection device 10 ... Stage 11 ... Measurement unit 110, 92 ... Camera 111, 91 ... Lighting device 12 ... Control device 13, 93.・ ・ Information processing device 14 ・ ・ ・ Display device 15, 95 ・ ・ ・ Calibration standard plate 94 ・ ・ ・ Movement mechanism H ・ ・ ・ Dust Y ・ ・ ・ Dirt

Claims (12)

  1. 　被検査物に対して、照明光を照射する照明手段と、
    　前記被検査物、及び、較正のために準備される較正用標準面を撮影する撮影手段と、
    　前記撮影手段によって撮影された画像を処理することによって、前記被検査物を検査する検査手段と、
    　前記撮影手段と前記較正用標準面とに平行な方向における相対位置が異なった状態で前記撮影手段によって撮影される前記較正用標準面の複数の画像から所定の特徴量を抽出し、該抽出された複数の特徴量の値に基づいて、一の調整用特徴量を算出する、調整用特徴量算出手段と、
    　を備え、
    　前記調整用特徴量に基づいて、前記照明手段の較正、及び／又は、撮影された画像の補正処理、を行う外観検査装置。     Lighting means that irradiates the object to be inspected with illumination light,
    An imaging means for photographing the object to be inspected and a standard surface for calibration prepared for calibration.
    An inspection means for inspecting the object to be inspected by processing an image taken by the photographing means, and an inspection means for inspecting the object to be inspected.
    A predetermined feature amount is extracted from a plurality of images of the calibration standard surface photographed by the imaging means in a state where the relative positions in the direction parallel to the calibration standard surface are different from those of the imaging means, and the extracted features are extracted. An adjustment feature amount calculation means that calculates one adjustment feature amount based on the values of a plurality of feature amounts, and an adjustment feature amount calculation means.
    With
    A visual inspection apparatus that calibrates the lighting means and / or corrects a captured image based on the adjustment feature amount.
  2. 　較正用標準板をさらに備え、前記較正用標準面は前記較正用標準板に設けられている、
    　ことを特徴とする、請求項１に記載の外観検査装置。     A calibration standard plate is further provided, and the calibration standard surface is provided on the calibration standard plate.
    The visual inspection apparatus according to claim 1, wherein the visual inspection apparatus is characterized in that.
  3. 　前記較正用標準板、及び／又は、前記撮影手段を、水平方向に移動させる、移動機構をさらに備える、
    　ことを特徴とする、請求項２に記載の外観検査装置。     A moving mechanism for moving the calibration standard plate and / or the photographing means in the horizontal direction is further provided.
    The visual inspection apparatus according to claim 2, wherein the visual inspection apparatus is characterized in that.
  4. 　前記調整用特徴量算出手段は、
    　前記複数の画像の特徴量の階調値を、１×１画素以上の領域毎に抽出し、前記複数の画像から抽出された前記領域毎の前記階調値の最頻値を、前記領域における前記調整用特徴量とする、
    　ことを特徴とする、請求項１から３のいずれか一項に記載の外観検査装置。     The adjustment feature amount calculation means is
    The gradation value of the feature amount of the plurality of images is extracted for each region of 1 × 1 pixel or more, and the mode value of the gradation value for each region extracted from the plurality of images is obtained in the region. The adjustment feature amount is used.
    The visual inspection apparatus according to any one of claims 1 to 3, wherein the visual inspection apparatus is characterized in that.
  5. 　前記照明光の照明条件を設定する照明条件設定手段、をさらに備え、
    　前記照明条件設定手段は、前記調整用特徴量と、予め設定されている基準特徴量との比較に基づいて前記照明光の照明条件を設定することで、前記照明手段の較正を行う、
    　ことを特徴とする、請求項１から４のいずれか一項に記載の外観検査装置。     A lighting condition setting means for setting the lighting condition of the illumination light is further provided.
    The illumination condition setting means calibrates the illumination means by setting the illumination conditions of the illumination light based on the comparison between the adjustment feature amount and the preset reference feature amount.
    The visual inspection apparatus according to any one of claims 1 to 4, wherein the visual inspection apparatus is characterized in that.
  6. 　前記調整用特徴量を用いて補正用画像を生成する、補正画像生成手段、をさらに備え、
    　前記画像の補正処理は、前記検査手段が、前記補正用画像に基づいて、前記撮影手段によって撮影された画像のシェーディング補正を行うことである、
    　請求項１から４のいずれか一項に記載の外観検査装置。     A correction image generation means for generating a correction image using the adjustment feature amount is further provided.
    The image correction process is such that the inspection means performs shading correction of an image taken by the photographing means based on the correction image.
    The visual inspection apparatus according to any one of claims 1 to 4.
  7. 　被検査物に照明光を照射して撮影された被検査物の画像に基づいて前記被検査物の検査を行う外観検査装置の較正を行う方法であって、
    　較正のために準備される較正用標準面に前記照明光を照射する照射ステップと、
    　前記照明光が照射された前記較正用標準面の異なる複数の範囲を撮影する撮影ステップ
    と、
    　前記撮影ステップで撮影された前記較正用標準面の複数の画像から、それぞれ特徴量を抽出する抽出ステップと、
    　抽出された複数の特徴量の値に基づいて、一の調整用特徴量を算出する算出ステップと、
    　前記調整用特徴量に基づいて、前記外観検査装置の較正を行う較正ステップと、
    　を有することを特徴とする、外観検査装置の較正方法。     It is a method of calibrating the visual inspection device that inspects the inspected object based on the image of the inspected object taken by irradiating the inspected object with illumination light.
    An irradiation step of irradiating the calibration standard surface prepared for calibration with the illumination light, and
    A photographing step of photographing a plurality of different ranges of the calibration standard surface irradiated with the illumination light, and
    An extraction step of extracting features from a plurality of images of the standard surface for calibration taken in the shooting step, and
    A calculation step for calculating one adjustment feature amount based on the extracted multiple feature amount values, and
    A calibration step for calibrating the visual inspection device based on the adjustment feature amount, and
    A method for calibrating a visual inspection device, which comprises.
  8. 　前記撮影ステップでは、前記較正用標準面、及び／又は、撮影手段を前記較正用標準面に平行な方向に移動させ、前記較正用標準面と前記撮影手段とに平行な方向における相対位置が異なる状態の前記較正用標準面の画像を、複数撮影する、
    　ことを特徴とする、請求項７に記載の外観検査装置の較正方法。     In the imaging step, the calibration standard surface and / or the imaging means is moved in a direction parallel to the calibration standard surface, and the relative positions of the calibration standard surface and the imaging means in a direction parallel to the imaging means are different. Take a plurality of images of the calibration standard surface of the state,
    The method for calibrating the visual inspection apparatus according to claim 7.
  9. 　前記抽出ステップでは、前記複数の画像の特徴量の階調値を、１×１画素以上の領域毎に抽出し、
    　前記算出ステップでは、前記複数の画像から抽出された前記領域毎の前記階調値の最頻値を、前記領域における前記調整用特徴量とする、
    　ことを特徴とする、請求項７又は８に記載の外観検査装置の較正方法。     In the extraction step, the gradation values of the feature amounts of the plurality of images are extracted for each region of 1 × 1 pixel or more.
    In the calculation step, the mode value of the gradation value for each of the regions extracted from the plurality of images is used as the adjustment feature amount in the region.
    The method for calibrating the visual inspection apparatus according to claim 7 or 8, wherein the visual inspection apparatus is characterized in that.
  10. 　前記較正ステップでは、前記調整用特徴量と、予め設定される基準特徴量とを比較することによって前記照明光の照明条件を較正する、
    　ことを特徴とする、請求項７から９のいずれか一項に記載の外観検査装置の較正方法。     In the calibration step, the illumination conditions of the illumination light are calibrated by comparing the adjustment feature amount with a preset reference feature amount.
    The method for calibrating a visual inspection apparatus according to any one of claims 7 to 9, wherein the visual inspection apparatus is characterized in that.
  11. 　前記較正ステップでは、前記調整用特徴量を用いて補正用画像を生成し、前記補正用画像に基づいて、前記被検査物の画像のシェーディング補正を行う、
    　ことを特徴とする、請求項７から９のいずれか一項に記載の外観検査装置の較正方法。     In the calibration step, a correction image is generated using the adjustment feature amount, and shading correction of the image of the object to be inspected is performed based on the correction image.
    The method for calibrating a visual inspection apparatus according to any one of claims 7 to 9, wherein the visual inspection apparatus is characterized in that.
  12. 　請求項７から１１のいずれか一項に記載の各ステップを外観検査装置に実行させるためのプログラム。
          A program for causing a visual inspection apparatus to perform each step according to any one of claims 7 to 11.
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