JP3846617B2 - Appearance inspection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a technical field including an appearance inspection device that takes in an image of an inspection object such as an aluminum electrolytic capacitor and inspects various display information such as characters, symbols, and graphics printed on the surface of the object. It belongs to.
[0002]
[Prior art]
  In the aluminum electrolytic capacitor, a pair of electrode terminals including a negative electrode terminal and a positive electrode terminal extend from the lower surface of a cylindrical main body. These two terminals are different in length from each other in order to distinguish between the positive electrode and the negative electrode. Specifically, the negative electrode terminal is short and the positive electrode terminal is long. On the other hand, predetermined display information is printed on the upper surface of the main body by inkjet or the like. The predetermined display information is, for example, display information such as a polarity mark, a manufacturer's company name, a lot number, a capacity, and a voltage such as characters, symbols, and figures.
[0003]
  Here, the polarity mark is a mark attached to a position corresponding to the negative electrode terminal, and the polarity mark can distinguish the positive electrode and the negative electrode even from the upper surface of the main body. In general, the polar mark is expressed by, for example, a black filled figure having a crescent or rectangular shape. Therefore, the display of the polarity mark is important for knowing the polarity.
[0004]
  In addition, the display information such as the company mark, lot number, capacity, voltage, etc. is usually printed in a line on a portion of the upper surface of the main body where no polarity mark is attached. The display of the company mark is important for specifying the manufacturer, and the display of the lot number is important for specifying the product. In addition, the capacity display is important for confirming whether the required capacity range is satisfied. The voltage display confirms that the voltage value used does not exceed the specified allowable voltage value. It is important to do.
[0005]
  Therefore, it is extremely important that these printed display information can be read reliably and are easy to read. From these viewpoints, it is necessary to inspect the display information at least before shipment.
[0006]
[Problems to be solved by the invention]
  Conventionally, however, inspection of good / bad display information attached to an aluminum electrolytic capacitor has been left to the operator's visual inspection.
[0007]
  Therefore, even if the production process of aluminum electrolytic capacitors is automated and the production efficiency is improved, visual inspection of display information cannot keep up with the production speed, and the efficiency up to product shipment must be reduced. Absent. In addition, a worker dedicated to visual inspection is required, resulting in high production costs.
[0008]
  In addition, since the visual inspection is an inspection by the worker, the judgment criteria for good / bad of each worker are different, the judgment criteria change from time to time even for the same worker, and in some cases, It is also assumed that a product that should be judged as defective is overlooked. As a result, variation in display information is likely to occur among individual aluminum electrolytic capacitors.
[0009]
  The present invention has been made in view of the above circumstances, and its main purpose is to automate the inspection of display information attached to an inspection object such as an aluminum electrolytic capacitor, and further, there is no variation in the inspection of display information. It is to be able to make the inspection less accurate.
[0010]
[Means for Solving the Problems and Effects of the Invention]
  Characteristic means capable of achieving the above object will be described below. For each means, characteristic actions and effects are described as necessary.
[0011]
  Means 1. An appearance inspection apparatus for determining the quality of multiple types of display information attached to the surface of an inspection object,
  An imaging means for receiving reflected light from the surface, and a multi-valued image obtained by the imaging means into a binary imageConvertible, Its binary imageAnd multi-valued imagesAn image processing device that determines the quality of display information based on
  The image processing apparatus divides the plurality of types of display information and performs pass / fail judgment processing for each display information, and
  The image processing apparatus is configured to detect the inspection object based on a binary image.Outline position of the area with display information, And setting a plurality of windows for the binary image based on the measurement results, and using each window to determine the quality of each display information,
  A first window of the windows is set so as to straddle an area to which display information is attached and an area to which display information is not attached.Multi-valued imageBy inspectingSwitching between bright and dark images in the first windowTo determine,
  A second window of the windows is set to have a size and position that includes a plurality of predetermined display information and partially deviates from the surface of the inspection object. When inspecting each display information, the area on the outer peripheral side than the surface is masked,
  The third of the windowsSaidOf inspection objectOutline of the area with display informationSet to straddle the inside and outside of
  In the third window and the first window, a bright image portion is extracted based on each multi-valued image, and the average value of the brightness of the bright image portion is set to the outer circumference than the surface of the inspection object. By applying it to the image data of the area on the side,An appearance inspection apparatus characterized by performing mask processing.
[0012]
  According to the means 1, the reflected light from the surface of the inspection object is received by the imaging means, and the multivalued image obtained by the imaging means is converted into a binary image by the image processing device. The image processing device uses this binary image.And multi-valued imagesIs used to determine the quality of the display information. Here, the image processing apparatus does not perform determination processing for all display information at once, but performs quality determination processing for each display information. Therefore, it is possible to determine quality for each display information. Judgment can be made automatically.
[0013]
  Although reflected light based on natural light can be received by the imaging means, a stable image can be obtained when the surface of the inspection object is actively illuminated by the illumination means and the reflected light is received by the imaging means. It is preferable when taking in.
Further, according to the means 1, instead of directly determining the binary image, a plurality of windows are set based on the surface position of the inspection object, and pass / fail determination is performed using each of the windows. There is an advantage that the targeted determination of the display information to be inspected can be made.
The first window is set so as to straddle the region with display information and the region without display information. Thereby, it is possible to determine the switching between the bright image and the dark image in the first window by scanning the inside of the first window from one side to the other. Such a determination result can be used as a material for determining the quality of display information. Such means is effective in determining the quality of the polarity mark in an aluminum electrolytic capacitor.
Further, according to the means 1, the second window is set so as to have a size and a position that include a plurality of predetermined display information and partially depart from the surface of the inspection object. Thereby, each display information contained in the second window can be inspected collectively, or the height or width of each display information can be inspected by scanning from one to the other. Such inspection results can be used as one material for determining the quality of display information. Such means is effective for determining the quality of an aluminum electrolytic capacitor such as a company mark, a lot number, a capacitance value, and a voltage value. Here, when the second window is set so as to include a plurality of display information as described above, particularly when the surface is circular or the like, an area on the outer peripheral side of the circular area is also included in the window. However, by masking the outer peripheral area, the outer peripheral area of the surface is not erroneously recognized as display information, so the second window is set without being restricted by the size of the surface. can do.
Further, in the means 1, the third window is set so as to straddle the inside and outside of the contour of the region to which the display information to be inspected is attached. In addition, mask processing is performed using the luminance in the third window. As a result, the mask process is executed while using the luminance of the actual image, so that the mask process can be reliably performed and the outside of the surface area can be reliably separated from the display information and inspected. Note that the mask processing can be made more reliable by averaging the luminance in the first window together with the luminance in the first window.
[0014]
  Mean 2. The appearance inspection apparatus according to claim 1, wherein the image processing apparatus further performs pass / fail determination processing in a minimum unit such as one character unit for each display information. According to the means 2, when the display information is composed of a plurality of characters, the pass / fail determination is performed in units of characters, that is, the minimum unit, and the accuracy of the pass / fail determination can be further improved.
[0015]
  Means 3. The means 1 or 2 according to claim 1, wherein when the multi-value image is converted into a binary image by the image processing device, a binarization threshold is set every time based on the luminance of the multi-value image. Appearance inspection device.
[0016]
  As a general method, the binarization threshold can be set to a predetermined constant value in consideration of various conditions. However, when the brightness of illumination changes or display information such as printing has light and shade, an accurate inspection cannot be performed if the binarization threshold is a constant value. On the other hand, according to the means 3, since the binarization threshold value is set every time based on the luminance of the multi-valued image, an accurate pass / fail judgment is performed without being affected by a change in illumination, shading of display information, or the like. be able to.
[0017]
  Specifically, for example, there are various methods such as setting an intermediate position between the darkest value and the brightest value in the multi-valued image as a threshold value, or taking into account the luminance deviation of the multi-valued image. The method of setting the intermediate position between the value and the darkest value is the simplest and is excellent in that the arithmetic processing can be executed quickly. In this case, it is optimal to set the center position between the brightest value and the darkest value as the binarization threshold. Of course, it is preferable that the setting of how the binarization threshold is determined can be appropriately set by the input means.
[0018]
  means4. The image processing apparatus includes a storage unit that stores storage data in a minimum unit such as one character unit for each display information, and stores the storage data stored in the storage unit as a minimum of an actual binary image corresponding to the storage unit. The reference data is generated by performing processing to match the vertical and horizontal sizes of the unit data, and the quality of each minimum unit is determined by using the reference data and comparing with the minimum unit data of the actual binary image. Means 1 to means characterized in that3The visual inspection apparatus according to any one of the above.
[0019]
  Such means4According to the above, storage data of the minimum unit is stored in the storage means, and the reference data is generated by performing processing for matching the storage data with the vertical and horizontal sizes of the minimum unit data of the actual binary image. Then, based on this reference data, a comparison determination with an actual binary image is performed. As a result, the storage means only needs to store data of several dots in the vertical and horizontal directions as the storage data, and the storage capacity can be reduced. In addition, since the reference data is processed so that the vertical and horizontal lengths match the vertical and horizontal directions of the minimum unit data of the actual binary image, it is possible to flexibly deal with characters or the like that extend in the vertical or horizontal direction.
[0020]
  means5. The image processing apparatus includes storage means for storing storage data in a minimum unit such as one character unit for each display information, and performs expansion and contraction processing using the minimum unit data for the storage data. Data and contraction data are generated, the minimum unit data of the actual binary image is compared with the expansion data and contraction data, respectively, and the degree of coincidence is examined. Based on the degree of coincidence, the quality of each minimum unit is determined. Means 1 to means characterized in that4The visual inspection apparatus according to any one of the above.
[0021]
  Such means5According to the above, instead of simply comparing the reference data with the minimum unit data of the actual binary image, the minimum unit of the actual binary image based on the expansion data obtained by expanding the reference data and the contracted contraction data. Since the comparison with the data is made, it is possible to reliably determine that a defect such as a character or a blur is defective. This comparison process is preferably performed by superimposing the expansion data and the actual minimum unit data to see the degree of coincidence, or superposing the contraction data and the actual minimum data to see the degree of coincidence. Further, the degree of coincidence is not necessarily 100%, and it is preferable that input can be set according to an allowable degree such as 95%.
[0022]
  means6. The appearance inspection apparatus according to claim 9, wherein the contraction process is a thinning process, and the contraction data is thin line data. In general contraction processing, contraction data does not always have a series of connections. In that case, if a discontinuous part of contraction data coincides with a discontinuous part of actual data, it should be judged as defective. There is a risk that things are judged as good. But such means6Accordingly, by adopting the thinning process among the shrinking processes, the thin line data becomes continuous data, and the optimum data can be provided as the reference data.
[0023]
  means7. The surface of the inspection object is a printing surface, and display information is printed on the printing surface.6The visual inspection apparatus according to any one of the above. Such means7According to the above, by making the printed information as display information, it is possible to determine a defect when the printing density is thin, the printing is blurred, or the printing is defective. Means4,5If print data is used as the storage data described in, the required storage capacity can be further reduced.
[0024]
  means8. Means 1 to means in which the surface of the inspection object is circular.7The visual inspection apparatus according to any one of the above. Such means8According to this, it is possible to determine the quality of the display information attached to the circular surface. In this case, as in the case of the second window, when a rectangular window including a plurality of predetermined display information is set, the second window is likely to approach the circular area on the surface. The mask processing can reliably distinguish the outside of the circular area from the display information.
[0025]
  means9. The appearance inspection apparatus according to means 7 or 8, wherein the inspection object is an aluminum electrolytic capacitor whose surface is formed of aluminum, and printing has a luminance different from the ground color of the printed surface. Such means9According to the above, it is possible to automatically determine whether the display information printed on the surface of the aluminum electrolytic capacitor, which could only be determined by visual inspection by a conventional worker, is acceptable.
[0026]
  means10. Means including at least a polarity mark and display information arranged in a plurality of stages as the plurality of types of display information, wherein the polarity mark is determined to be good or bad by an inspection item different from other display information.9Appearance inspection apparatus as described. Such means9Accordingly, the inspection of the polarity mark peculiar to the aluminum electrolytic capacitor is inspected separately from information such as other characters, so that the quality of the polarity mark can be reliably determined. The determination of pass / fail of the polarity mark can be made by, for example, a width inspection of the polarity mark and an area inspection in a window set in the polarity mark.
[0027]
  still,Means 1 to10A printing apparatus comprising the appearance inspection apparatus according to any one ofIt is also possible to embody.TakePrinting deviceAccordingly, when the display information is attached by printing, the appearance inspection of the display information can be performed simultaneously with the printing process, and the production efficiency of the inspection object is improved.
[0028]
  In addition, the printing apparatusA printing unit that prints display information on a surface of the inspection object; and a transfer unit that transfers the inspection object from the printing unit to the appearance inspection device. The inspection object is transferred while keeping the posture of the inspection object constant until the inspection byIt is good.
[0029]
  TakeConstitutionAccording to the above, since the posture of the inspection object is kept constant by the transfer means between the printing process and the inspection process, the surface of the inspection object which is the inspection point is arranged in a constant posture between the printing process and the inspection process. This eliminates the need to correct the surface posture one by one during the inspection process. The inspection object is a means.9In the case of the aluminum electrolytic capacitor as described in (1), it is possible to hold the capacitor in a fixed posture by moving the pair of electrode terminals while holding the pair of electrode terminals by the transfer means.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, an embodiment will be described with reference to FIGS.
[0031]
  In this embodiment, a case where an inspection object is an aluminum electrolytic capacitor 1 (hereinafter referred to as a capacitor) will be described.
[0032]
  As shown in FIGS. 1B to 1D, the capacitor 1 includes an aluminum main body 2 whose outer shape is substantially cylindrical, and a pair of electrode terminals 3 extending from the lower surface of the main body 2 and having different lengths. , 4. The difference in length between the electrode terminals 3 and 4 is provided so that the positive electrode and the negative electrode can be distinguished at a glance. Specifically, the negative terminal 3 is short and the positive terminal 4 is long.
[0033]
  The upper surface (surface) of the main body 2 of the capacitor 1 is a circular and flat printing surface 5. As shown in FIG. 5, predetermined display information is printed on the printing surface 5 by inkjet. Here, the predetermined display information includes the polarity mark 6, the manufacturer's company mark 7, the lot number 8, the capacity value 9, and the voltage value 10, which are display information such as other characters, symbols, and figures. Also good.
[0034]
  Here, the polarity mark 6 is a mark attached to a position corresponding to the negative electrode terminal 3, and the polarity mark 6 can distinguish the positive electrode and the negative electrode even from the upper surface of the main body 2. Here, the polar mark 6 is represented by a black filled figure having a crescent shape.
[0035]
  In addition, the company mark 7 is represented here by a black solid figure having a substantially elliptical shape as an example, and the manufacturer of the capacitor 1 can be identified by this display information. The lot number 8 is for specifying the product type and is often expressed by a predetermined number or alphabetic character, but here, as an example, a case where it is composed of three characters “ABC” will be described. To do.
[0036]
  The capacitance value 9 represents the maximum capacitance of the capacitor 1 by a numerical value, and “1” is displayed here. The voltage value 10 represents the allowable voltage of the capacitor 1 as a numerical value, and “50 V” is displayed here.
[0037]
  Next, an outline of the printing apparatus 11 for printing on the printing surface 5 of the capacitor 1 will be described. As shown in FIG. 1A, the printing apparatus 11 includes a loading and aligning device 12, a direction correcting device 13, a printing processing device 14 as a printing unit, from the upstream side to the downstream side in the transfer direction of the capacitor 1. A curing processing device 15, an appearance inspection device 16, and a sorting processing device 17 are provided in this order.
[0038]
  A capacitor 1 before printing is input to the input alignment device 12. As shown in FIG. 1 (b), the capacitors 1 before printing that are input to the input / alignment device 12 are randomly arranged, but after being aligned in a line in the input / alignment device 12, the next direction correction device 13. Sent out. As shown in FIG. 1 (c), the alignment here means that the printed surface 5 of the capacitor 1 is arranged upward and the terminals 3 and 4 are arranged downward, but the negative terminal 3 and the positive terminal 4 are arranged. The context of is disjoint.
[0039]
  In the direction correcting device 13, the length difference between the electrode terminals 3 and 4 is inspected while the main body 2 is gripped by a chuck (not shown). In order to match with 1, the process of rotating the chuck 180 degrees is performed. As a result, as shown in FIG. 1 (d), the front and back relations of the electrode terminals 3 and 4 also coincide with each other and are sent to the next print processing apparatus 14.
[0040]
  Since the main body 2 is gripped by the chuck in the direction correcting device 13 when being fed into the print processing device 14, the chuck 18 (both electrodes 3 and 4 are used as transfer means on the print processing device 14 side). The capacitor 1 is exchanged by gripping with reference to FIG. In the print processing device 14, the display information of the polarity mark 6, company logo 7, lot number 8, capacitance value 9, and voltage value 10 is printed on the printing surface 5 that is the upper surface of the capacitor 1. In this embodiment, an ink jet method is adopted as a transfer method.
[0041]
  Thereafter, the curing processing device 15 performs a curing process on the printing surface 5 side using ultraviolet rays. Thereby, each display information printed on the printing surface 5 becomes difficult to drop.
[0042]
  Next, the capacitor 1 is sent to the appearance inspection device 16. As shown in FIG. 2, in the appearance inspection apparatus 16, an illumination 19 that illuminates the printing surface 5 side, and a CCD camera 20 as an imaging unit that receives reflected light from the printing surface 5 based on the illumination 19. Is disposed in proximity to the conveyance site of the capacitor 1. The appearance inspection device 16 inspects the quality of the printing surface 5 based on the image data captured by the CCD camera 20. In addition, since the capacitor 1 is held in a fixed posture with the printing surface 5 facing upward from the print processing device 14 to the appearance inspection device 16 by the chuck 18, the flow of work from the printing process to the inspection process is smooth. Can be.
[0043]
  According to the inspection result by the appearance inspection device 16, the capacitor 1 is classified into a non-defective product and a defective product, and these are separated by the separation processing device 17. That is, the capacitor 1 determined to be defective is discarded. On the other hand, the capacitor 1 determined to be non-defective is conveyed to a chip mounting device 21 provided separately from the printing device 11.
[0044]
  In the chip mounting device 21, processing for connecting the chip 22 and both the terminals 3 and 4 is performed, and processing for mounting the main body 2 on the chip 22 is performed. Thereby, as shown in FIG. 1E, the chip type capacitor 1 in which the main body 2 is mounted on the chip 22 is completed.
[0045]
  Next, based on the block diagram shown in FIG. 3, a configuration centering on the image processing unit 25 as image processing means in the appearance inspection apparatus 16 will be described.
[0046]
  The image processing unit 25 includes an A / D converter 26. The CCD camera 20 is connected to an A / D converter 26. The image data that is an analog signal captured by the CCD camera 20 is converted into a digital signal by the A / D converter 26. The A / D converter 26 includes an image memory 27 for storing digitized image data, a video mixer 28 for mixing and outputting input signals, and calculating the appearance from the image data by a predetermined calculation method. Calculation logic 29 is connected to each other. The image memory 27 and the calculation logic 29 are connected to a control logic 30 that defines each operation.
[0047]
  The image processing unit 25 is provided with a CPU 31 as a control unit that performs calculation and control processing collectively. The CPU 31, the image memory 27, and the calculation logic 29 are connected bidirectionally. Connected to the CPU 31 are a ROM 32 as a storage means for storing a control program and the like, and a RAM 33 as a storage means for temporarily storing data such as inputted setting values and inspection calculation results regarding various display information. .
[0048]
  An input / output device 34 is connected to the CPU 31. A start means (not shown) for driving the appearance inspection apparatus 16 is connected to the input / output device 34, and an appearance inspection centered on the CPU 31 is executed based on a predetermined start signal from the start means. Further, an inspection display means (not shown) is connected to the input / output device 34, and a determination signal indicating whether or not the printing state of the capacitor 1 is normal is output from the CPU 31 to the separation processing device 17 or the like.
[0049]
  The input / output device 34 is further connected with a keyboard 35 as external input means or setting means. Various settings relating to the appearance inspection are performed by an input operation of the keyboard 35. Further, a display monitor 36 as a display device is connected to the video mixer 28. An image is displayed on the display monitor 36 based on a signal from the video mixer 28 so that the operator can recognize the appearance of the capacitor 1, here, the printing state of the printing surface 5.
[0050]
  Next, an appearance inspection procedure performed by the appearance inspection apparatus 16 having the above-described configuration will be described with reference to a flowchart showing a processing procedure for executing an appearance inspection of one capacitor 1 shown in FIG. This series of processing is executed by the control processing of the CPU 31.
[0051]
  First, in step S1, the presence or absence of the capacitor 1 is determined. As shown in FIG. 2, if the capacitor 1 is arranged at a position opposite to the CCD camera 20, the reflected light from the capacitor 1 illuminated by the illumination 19 is taken into the CCD camera 20. The determination is made and the process proceeds to the next step S2. On the other hand, when the capacitor 1 is not located opposite to the CCD camera 20, the light from the illumination 19 is not captured as reflected light by the CCD camera 20, and it is determined that the capacitor 1 does not exist and a series of processing is performed. Exit once.
[0052]
  In step S2, a binarization threshold setting process is executed. This process is an arithmetic process using the highest value D1 and the lowest value D2 of the image data which is multi-value data captured from the CCD camera 20. Specifically, the set value v is input in advance using the keyboard 35,
(D1-D2) · v + D2
A binarization threshold value is calculated by substituting each value into the formula. Here, if 0.5 (50%) is set as the setting value v, the binarization threshold value is set to a central value between the highest value D1 and the lowest value D2. Thus, since the binarization threshold is not fixed and is set each time, a suitable binarization threshold is set regardless of the change in the brightness of the illumination 19 over time or the difference in the print color density. Obtainable. Of course, by appropriately changing the set value v to, for example, 0.45 or 0.6 by the input setting using the keyboard 35, it is possible to obtain an optimal binarization threshold corresponding to the inspection environment or the like. Note that instead of taking an intermediate point as described above, it is also possible to set a binarization threshold in consideration of a luminance deviation. In step S2, binarization processing of image data that is multi-value data is performed based on the calculated binarization threshold. A binary image is obtained by this binarization processing.
[0053]
  6 and subsequent drawings, for convenience of explanation, the dark image of the binary image is indicated by hatching, and the printing surface 5, the polarity mark 6, the company mark 7, the lot number 8, and the capacity value 9 are shown. The image corresponding to each display information of the voltage value 10 is also given the same symbol. Further, in the following description, expressions such as up, down, left, and right are used with reference to the orientation of each display information on the printing surface 6.
[0054]
  In step S3, a body position measurement process is executed. This process measures the position of the surface of the main body 2, that is, the printing surface 5 as shown in FIG. 6 based on the binary image obtained in step S 2. In step S2, the upper end point P1, the right end point P2, and the lower end point P3 are measured based on the light / dark boundary of the binary image. Moreover, the center point P0 of the printing surface 5 is calculated | required by calculating using these points P1-P3. Furthermore, the left end point P4 is obtained by performing arithmetic processing using these points P0 to P3. The reason why the left end point P4 is calculated is that the left end point P4 cannot be distinguished from the dark image corresponding to the polarity mark 6 and the dark image on the outer peripheral side of the main body 2.
[0055]
  In step S4, a window setting process is executed. Here, six windows are set, and these are all set with reference to the coordinate values of the points P0 to P4 subjected to the measurement calculation processing in step S3. That is, as shown in FIG. 7, the window W1 is set in a vertically long rectangular shape including the upper end point P1, the window W2 is set in a horizontally long rectangular shape including the right end point P2, and the window W3 is vertically long including the lower end point P3. It is set to a rectangular shape. The window W4 has a horizontally long rectangular shape on the printing surface 5, and the left side approaches a dark image corresponding to the polar mark 6 and the right side becomes a bright image portion without any other display information 7-10. Set to The window W5 is set to a vertically long rectangular shape in which all of the dark image corresponding to the polarity mark 6 when printing is normal is included. The window W6 is set to a rectangular shape that covers only the dark image corresponding to the polar mark 6 and includes all the dark images corresponding to the other display information 7-10. These windows W1 to W6 are appropriately used in the following image inspection.
[0056]
  In step S5, the measurement process of the polarity mark 6 is executed. Here, as shown in FIG. 8, the left end point P4 is detected by the process at step S3, and the window W4 and the window W5 are set by the process at step S4. Measure the width and area of the corresponding dark image. The measurement of the width of the dark image corresponding to the polar mark 6 will be described. The left end of the dark image corresponding to the polar mark 6 is the left end point P4, but the right end point is unknown. Therefore, when the window W4 is scanned from the right side, there is a point where the bright image is switched to the dark image, and can be regarded as the right end point. The width t1 of the dark image corresponding to the polarity mark 6 is measured from both the left and right points. Next, the area of the polarity mark 6 is measured by the window W5. If the window W5 is normal, it should be a dark image.
[0057]
  In step S6, pass / fail judgment processing for the polarity mark 6 is executed. Here, it is determined whether or not the width t1 and the area of the dark image corresponding to the polarity mark 6 obtained in step S5 are within allowable values. Each allowable value is set in advance via the keyboard 35. Specifically, when the width t1 is less than the preset allowable value or when the area is less than the preset allowable area value, the process jumps to step S19 to perform defective product determination processing. For example, when the width t1 of the polarity mark 6 is short, it is determined that the necessary and sufficient size of the polarity mark 6 has not been printed, and is defective. Further, regarding the area of the polarity mark 6 (area in the window W5), if there is a defect in printing, it is determined to be defective. On the other hand, if the measured width t1 and area are within the allowable values, the polarity mark 6 is assumed to be printed normally and the process proceeds to step S7.
[0058]
  In step S7, a mask process is executed. From this processing step, it is executed to determine whether each display information 7 to 10 other than the polarity mark 6 is normally printed. Therefore, in step S7, attention is first focused on the window W6 including these pieces of display information 7-10. In the window W6, all of the display information 7 to 10 are surely included, and the print surface 5 is circular, so that the upper right portion W6a and the lower right portion W6b of the window W6 are background images. You are approaching a dark image. Therefore, it is necessary to distinguish the upper right portion W6a and the lower right portion W6b from the display information 7 to 10. Therefore, first, the average value of the brightness of the bright image portion of the window W1 and the window W4 is calculated, and processing is performed so that the background image around the printing surface 5 has the calculated brightness. Accordingly, the background image is regarded as a bright image, and the upper right portion W6a and the lower right portion W6b in the window W6 are also switched to the bright image. Note that the average value of the brightness of the window W1 and the window W4 is used by surely averaging even if the unscheduled print portion is included in the bright image portion in one of the windows W1 or W4. This is because the mask process can be executed.
[0059]
  In step S8, a character string cut-out process is executed. In addition, although expressed as a character or a character string below, they have the same meaning as display information including numbers, symbols, figures, etc., and are used only for convenience of explanation. Here, as shown in FIG. 10, the image of the window W6 masked in step S7 is used, and the image in the window W6 is scanned from top to bottom. Then, there is a place where the bright image is switched to the dark image. This is the upper end position of the dark image corresponding to the company mark 7. When scanning is further continued, there is a place where the dark image is switched to the bright image. This is the lower end position of the dark image corresponding to the company mark 7. If scanning is further continued, switching between a bright image and a dark image is repeated. As a result, the heights h1, h2, h3, h4 of the respective dark images corresponding to the display information 7 to 10 and the height H including all the dark images corresponding to the display information 7 to 10 are measured. .
[0060]
  In step S9, a determination process regarding the height of the entire character string is executed. Here, it is determined whether or not the overall height H of each display information 7 to 10 measured in step S8 is within a predetermined allowable value. This allowable value is set in advance via the keyboard 35. Specifically, when the height H does not fall within the preset allowable range (between the upper limit value and the lower limit value), the process jumps to step S19 to perform defective product determination processing. For example, when the display information 7 to 10 overlap each other, the height H is shortened and it is determined as defective. On the other hand, if the measured height H is within the allowable value, it is assumed that the display information 7 to 10 as a whole is normal, and the process proceeds to step S10.
[0061]
  In step S10, a determination process regarding the height of each character string is executed. Here, it is determined whether or not the heights h1 to h4 for each display information 7 to 10 measured in step S8 are within a predetermined allowable value. This allowable value is set in advance via the keyboard 35. Specifically, when the heights h1 to h4 do not belong to the preset allowable range (between the upper limit value and the lower limit value), the process jumps to step S19 to perform defective product determination processing. For example, in the case where the upper half corresponding to the company mark 7 is not printed, the height h1 is shortened and it is determined as defective. On the other hand, if all the measured heights h1 to h4 are within the allowable value, the heights h1 to h4 of the display information 7 to 10 are all normal, and the process proceeds to step S11.
[0062]
  In step S11, a width measurement process for each character string is executed. Here, the image of the window W6 masked in step S7 is used, and the image in the window W6 is scanned from left to right and from right to left. For example, in the portion corresponding to the dark image corresponding to the company mark 7, there is a place where the bright image is switched to the dark image when scanned from left to right. This is the left end position of the dark image corresponding to the company mark 7. Conversely, when scanning from right to left, there is a place where a bright image is switched to a dark image. This is the right end position of the dark image corresponding to the company mark 7. And the same process is performed also about each other display information 8-10. Thereby, as shown in FIG. 10, each width | variety d1, d2, d3, d4 of each dark image corresponding to each display information 7-10 is measured.
[0063]
  In step S12, a determination process regarding the width of each character string is executed. Here, it is determined whether or not the widths h1 to h4 for each display information 7 to 10 measured in step S11 are within a predetermined allowable value. This allowable value is set in advance via the keyboard 35. Specifically, when the widths d1 to d4 do not belong to the preset allowable range (between the upper limit value and the lower limit value), the process jumps to step S19 to perform defective product determination processing. For example, when the right half corresponding to the lot number 8 is not printed, the width d2 is shortened and it is determined as defective. On the other hand, if the measured widths d1 to d4 are within the allowable value, the display information 7 to 10 and the individual widths d1 to d4 are assumed to be normal, and the process proceeds to step S13.
[0064]
  In step S13, a process for cutting out each character is executed. In other words, in the above processing steps, measurement processing and determination processing in character string units are performed, but thereafter measurement processing and determination processing in character units, that is, minimum units are performed more finely. Here, as shown in FIG. 11A, description will be made by paying attention to display information “50 V” that is a display of the voltage value 10. First, it is assumed that the number of character strings, the number of characters of each character string, the character type, and the like are set in advance by an input operation from the keyboard 36. In the present embodiment, the capacitor 1 is set before the appearance inspection. The input settings for all the display information 6 to 10 are made according to the type. Thus, for example, if the voltage value is 10, the character string is the fourth column, and three characters are printed here, and the three characters are character types “5”, “0”, and “V” in order from the left. I know that there is. Accordingly, here, as shown in FIG. 11A, a process of cutting out each character by dividing the width d4, which is a dark image applied to the voltage value 10 measured in step S8, into three equal parts. As for the display information of the voltage value 10, a dark image corresponding to “5” will be described as an image c1, a dark image corresponding to “0” will be described as an image c2, and a dark image corresponding to “V” will be described as an image c3. Then, the images c1 to c3 are partitioned by a bright image portion that is a gap between characters. However, if the images c1 to c3 are close to each other or their intervals are irregular, the images c1 to c3 may overlap the partition line. In this case, the partition line is left and right. A process for adjusting the position is performed. In this way, as shown in FIG. 11B, the images c1 to c3 are cut out individually. Thereafter, for each of the images c1 to c3, as shown in FIG. 11C, a process for setting a circumscribed rectangle is executed. Further, the area occupied by the dark image in the circumscribed rectangle is measured.
[0065]
  In step S14, a determination process regarding the areas of the images c1 to c3 is executed. Here, it is determined whether or not the area of each dark image for each of the images c1 to c3 measured in step S13 is within a predetermined allowable value. This allowable value is set in advance via the keyboard 35. Specifically, if each area does not belong to the preset allowable range (between the upper limit value and the lower limit value), the process jumps to step S19 to perform defective product determination processing. On the other hand, if the measured areas are within the allowable values, the areas of the images c1 to c3 are assumed to be normal, and the process proceeds to step S15.
[0066]
  In step S15, expansion / contraction processing is executed. Here, only the image c3 will be described, but it goes without saying that it is executed for all other images. As shown in FIG. 12A, the RAM 33 stores dot data of 7 dots vertically and 5 dots horizontally. Since only a very small amount of data needs to be stored in this way, the storage capacity of the RAM 33 is not wasted. The stored data i uses font data at the time of printing. For this stored data i, the actually obtained image c3 (see FIG. 11 (c)) has a large number of dots and cannot be directly compared. Therefore, normalization processing is executed prior to expansion / contraction processing. The normalization process is a process for making the stored data i and the circumscribed square of the actual image c3 the same. For example, as shown in FIG. 11C, when the circumscribed rectangle of the image c3 is vertical x dots and horizontal y dots, processing for adjusting the vertical and horizontal lengths of the stored data i is performed. Specifically, the stored data i is multiplied by x / 7 in the vertical direction and y / 5 times in the horizontal direction. As a result, as shown in FIG. 12B, reference data I having the same circumscribed rectangle as the image c3 is generated. Since the reference data I is generated by matching the vertical x and horizontal y of the image 3c each time as described above, the size of the image c3 is different, or the image is a vertically or horizontally long image. Even in this case, the most optimal data can be provided as the reference data I.
[0067]
  After the normalization process ends, the expansion / contraction process of the reference data I is executed. First, the contraction process will be described. Here, the thinning process is executed among the shrinking processes. Thinning is generally referred to as “an operation to convert a linear figure into a sequence of points existing in the center of the width while maintaining the connectivity of the figure.” Here, the same processing is performed. The thin line data Ia is generated as shown in FIG. Note that the shrinkage data obtained in general shrinkage processing may be interrupted and the continuity may be lost. Therefore, when inspecting continuous linear figures such as characters as in this embodiment, thinning processing is performed. It is preferable to apply. Next, the expansion process will be described. The expansion is “an operation for changing the neighborhood of one pixel to 1”, and is generally performed by adopting a known “4-neighbor” or “8-neighbor” as the neighborhood. Yes, by performing the same processing here, the expansion data Ib is generated as shown in FIG.
[0068]
  In step S16, an overlay process is executed. The reference data for the superimposition processing is the thin line data Ia and the expansion data Ib generated by the expansion / contraction processing in step S15. Further, the comparison data to be superimposed on these is the image captured this time, and here is the image c3. Then, as shown in FIG. 13A, a process of superimposing the thin line data Ia and the image c3 is performed. Further, as shown in FIG. 13B, a process of superimposing the expansion data Ib and the image c3 is performed.
[0069]
  In step S17, a process for determining the degree of coincidence is executed for the result of superposition in step S16. The allowable value of the degree of coincidence is set in advance by an input operation using the keyboard 35, and can be set as necessary, for example, 98%. Then, as a result of superimposing the thin line data Ia and the image c3, the degree of coincidence is determined with 100% being the case where all the thin line data Ia is included in the dark image area of the image c3. Further, the degree of coincidence is determined with 100% being the case where all the images c3 are included in the dark image area of the expansion data Ib as a result of superimposing the expansion data Ib and the image c3. If one of the respective degrees of coincidence falls below the allowable value (lower limit value), the process proceeds to step S19 to determine defective products.
[0070]
  For example, when the missing portion c3a exists in the image c3 as shown in FIG. 13A or when the protruding portion c3b exists in the image c3 as shown in FIG. When the degree of coincidence falls below the lower limit, which is the allowable value, it is determined as a defective product. As a result, it is possible to reliably determine defectiveness or blurring of printed characters in each character unit that is the minimum unit. On the other hand, if the degree of coincidence is within the allowable value, the print character of the image c3 is assumed to be normal, and the process proceeds to step S18.
[0071]
  In step S18, a non-defective product determination process is executed. That is, only those that have cleared all the above inspection items are determined to be non-defective products, and those that cannot be cleared in steps S6, S9, S10, and S17 are all determined to be defective products in step S19, and one capacitor 1 The inspection process for is completed. The capacitors 1 determined as defective in step S19 are separated from non-defective products by the separation processing device 17 in FIG. On the other hand, the capacitor 1 determined to be non-defective in step S18 is transported to the chip mounting device 21 to be the chip capacitor 1 as the final product.
[0072]
  According to the visual inspection apparatus 16 described above, when the printed surface 5 of the capacitor 1 is inspected, it is possible to eliminate an operator's visual inspection and perform an automatic inspection using image processing. As a result, the production efficiency of the capacitor 1 including inspection can be improved, and the manufacturing cost can be reduced.
[0073]
  Further, it is possible to eliminate the bad effects caused by the visual inspection by the operator, for example, the variation of the determination criteria of the quality, and the quality of the printing state can always be determined at a constant level. As a result, the variation between the products of the capacitor 1 is reduced.
[0074]
  Moreover, since the appearance inspection apparatus 16 is incorporated in the printing apparatus 11, it can be shifted to the inspection as it is after printing. Moreover, since the capacitor 1 is constantly fixed by the chuck 18 from the time of printing to the time of inspection, the posture of the capacitor 1 can be inspected while being held in the same state as at the time of printing. It is no longer necessary to make a major correction. As a result, the inspection efficiency of the printing surface 5 is also significantly improved.
[0075]
  Further, since individual characteristics regarding the inspection of the printing surface 5 are apparent from the explanations in the respective processing steps S1 to S19, they will not be described in detail. The print surface 5 can be simply inspected by various distinctive processes such as inspection for distinguishing the display information 7 from 10 and other display information, processing for cutting out each character string or character, and checking the degree of matching of each character. In addition, there is an advantage that the quality determination can be performed appropriately.
[0076]
  In addition, since the setting values used for the determination processing in steps S6, S9, S10, S12, S14, and S17 can be input and set via the keyboard 35, each display information 6 to 10 on the printing surface 5 is requested. It is possible to make appropriate adjustments depending on the sharpness of the prints to be made and the degree of the shape of the characters. Of course, for example, if there is a request that only the lot number 8 should be clarified, it is possible to set the judgment criteria strictly for the set value in that part, so inspections according to the situation and request can be easily realized. can do.
[0077]
  In the present embodiment, the inspection object is the capacitor 1, particularly the aluminum electrolytic capacitor. However, the present invention is not limited to this and may be another capacitor. Moreover, it is not limited to a capacitor, and other electric / electronic components may be used. Furthermore, it is not limited to electrical / electronic components, but may be other articles.
[0078]
  In the present embodiment, the case where the printing state of the printing surface 5 is inspected has been described. However, other display information such as a seal or a printed character may be inspected instead of printing. In other words, it may be based on the premise that the brightness of the display information and other portions are different.
[0079]
  In addition, the appearance inspection device 16 is not attached to the printing device 11, but may be installed in a place that can be separately inspected after display information is attached to the inspection object, such as printing. Therefore, it may be installed independently from the printing apparatus 11 or the like.
[Brief description of the drawings]
1A is a schematic diagram of a printing apparatus and a chip mounting apparatus according to an embodiment, FIG. 1B is a diagram showing an alignment state of capacitors, and FIG. 1E is a chip shape. The perspective view which shows a capacitor | condenser.
FIG. 2 is a front view showing an inspection state by an appearance inspection apparatus.
FIG. 3 is a block diagram of an appearance inspection apparatus.
FIG. 4 is a flowchart showing an inspection procedure by an appearance inspection apparatus.
FIG. 5 is a plan view of a capacitor.
FIG. 6 is an explanatory diagram of an inspection image at the time of measuring a main body position.
FIG. 7 is an explanatory diagram of an inspection image when a window is set.
FIG. 8 is an explanatory diagram of an inspection image at the time of polarity mark inspection.
FIG. 9 is an explanatory diagram of an inspection image at the time of mask processing.
FIG. 10 is an explanatory diagram of an inspection image when measuring a character string height and width.
11A is an explanatory diagram of an inspection image when each character is cut out, FIG. 11B is an explanatory diagram of the inspection image after each character is cut out, and FIG. 11C is an explanatory diagram of the inspection image when a circumscribed rectangle is set.
12A is an explanatory diagram of stored data, FIG. 12B is an explanatory diagram of reference data after normalizing the stored data, FIG. 12C is an explanatory diagram of thin line data, and FIG. Illustration.
FIG. 13A is an explanatory diagram at the time of superimposing processing with thin line data, and FIG. 13B is an explanatory diagram at the time of superimposing processing with expansion data.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Capacitor as inspection object, 2 ... Main body, 3, 4 ... Negative electrode terminal and positive electrode terminal as electrode terminals, 5 ... Printed surface as surface to be inspected surface, 6-10 ... Polarity mark as display information , Company mark, lot number, capacity value and voltage value, 11 ... printing device, 14 ... printing processing device as printing means, 16 ... visual inspection device, 18 ... chuck as transferring means, 19 ... illumination, 20 ... CCD camera , 25: Image processing unit as image processing means, 26: A / D converter, 27: Image memory, 28: Video mixer, 29 ... Calculation logic, 30 ... Control logic, 31 ... CPU, 32 ... ROM as storage means 33 ... RAM as storage means, 34 ... input / output device, 35 ... keyboard as input means, 36 ... display monitor as display means, W1 to W6 Wind, i ... stored data, I ... reference data, Ia ... fine line data, Ib ... inflation data.

Claims (10)

An appearance inspection apparatus for determining the quality of multiple types of display information attached to the surface of an inspection object,
An imaging unit that receives reflected light from the surface, and a multi-valued image obtained by the imaging unit can be converted into a binary image, and the quality of display information is determined based on the binary image and the multi-valued image. An image processing device for
The image processing apparatus divides the plurality of types of display information and performs pass / fail judgment processing for each display information, and
The image processing device measures the contour position of the region to which the display information of the inspection object is attached based on the binary image, sets a plurality of windows on the binary image based on the measurement result, Use the window to determine the quality of each display information.
By setting the first window of the windows so as to straddle the area with display information and the area without display information, and inspecting the multi-valued image in the first window, The switching between the bright image and the dark image in the first window is determined,
A second window of the windows is set to have a size and position that includes a plurality of predetermined display information and partially deviates from the surface of the inspection object. When inspecting each display information, the area on the outer peripheral side than the surface is masked,
The third window of said window, and set so as to extend in and out of the contour of the display information of the inspection object is attached region,
In the third window and the first window, a bright image portion is extracted based on each multi-valued image, and the average value of the brightness of the bright image portion is set to the outer circumference than the surface of the inspection object. A visual inspection apparatus characterized by performing mask processing in the second window by applying to the image data of the side area .   The appearance inspection apparatus according to claim 1, wherein the image processing apparatus further performs pass / fail determination processing in a minimum unit such as one character unit for each display information. 3. The binarization threshold value is set every time based on the luminance of the multi-value image when the multi-value image is converted into a binary image by the image processing device. 2. An appearance inspection apparatus according to 1. The image processing apparatus includes a storage unit that stores storage data in a minimum unit such as one character unit for each display information, and stores the storage data stored in the storage unit as a minimum of an actual binary image corresponding to the storage unit. The reference data is generated by performing processing to match the vertical and horizontal sizes of the unit data, and the quality of each minimum unit is determined by using the reference data and comparing with the minimum unit data of the actual binary image. The appearance inspection apparatus according to any one of claims 1 to 3 , wherein the appearance inspection apparatus is provided. The image processing apparatus includes storage means for storing storage data in a minimum unit such as one character unit for each display information, and performs expansion and contraction processing using the minimum unit data for the storage data. Data and contraction data are generated, the minimum unit data of the actual binary image is compared with the expansion data and contraction data, respectively, and the degree of coincidence is checked. Based on the degree of coincidence, the quality of each minimum unit is determined appearance inspection apparatus according to any claims 1 to 4, characterized in that. The appearance inspection apparatus according to claim 5 , wherein the contraction process is a thinning process, and the contraction data is thin line data. The appearance inspection apparatus according to any one of claims 1 to 6 , wherein a surface of the inspection object is a printing surface, and display information is printed on the printing surface. Appearance inspection apparatus according to any one of claims 1 to 7 the surface of the inspection object has a circular shape. The appearance inspection apparatus according to claim 7 or 8 , wherein the inspection object is an aluminum electrolytic capacitor having a surface formed of aluminum, and printing has a luminance different from a ground color of a printed surface. As the display information of a plurality of types, and a display information arranged in at least the polarity marks and a plurality of stages, according to claim wherein the polarity marked other display information, characterized in that quality determination at different test items 9 Appearance inspection apparatus as described.

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