Vision testing method for pin-shaped components

Abstract

This provides a method for automating the visual inspection of pogo pins. [Solution] An embodiment of the present invention provides a vision inspection method for a pin-shaped component, comprising the steps of: attaching the pin-shaped component to the upper surface of an inspection stage in an inclined position; correcting the pin-shaped component to an upright position based on a magnet; rotating the pin-shaped component and photographing its surface; and performing a defect inspection on the pin-shaped component based on a plurality of captured images of the surface of the pin-shaped component.

Description

Technical Field

[0001] The present invention relates to a vision inspection method for pin-shaped parts. Further, this application is the result of the "Scale-up Technology Commercialization Program" (development of Pogo Pin appearance inspection equipment based on a reconfigured production system and verification of mass production by demand enterprises, project number: P0023213) supervised by the Korea Institute of Industrial Technology (KIAT).

Background Art

[0002] The shift to a data economy is rapidly increasing semiconductor demand in various industrial fields such as autonomous driving vehicles, robots, 5G, and mobile home appliances as technologies such as AI, IoT, and big data develop. In the semiconductor process, Pogopin is required as a core component for semiconductor performance and reliability tests. Korean Registered Patent No. 1204273 is disclosed in relation to such Pogopin.

[0003] Such Pogopin has a minimum diameter of around 0.15 mm and a minimum length of 1 mm, and is produced in various specifications. Until now, the appearance inspection of Pogopin has been carried out by visual inspection with a microscope, and the classification work has also been done manually, resulting in a problem of low production efficiency.

[0004] In order to solve the conventional problems, a method for automatically performing the appearance inspection of Pogopin is required, and moreover, there is a need for means to maintain Pogopin in an appropriate posture while the appearance inspection of Pogopin is essentially carried out.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved by the present invention is to provide a method capable of automating the appearance inspection of Pogopin.

[0006] Furthermore, the problem that the present invention aims to solve is to provide a vision inspection method with improved precision and reliability for the side surface of a pogo pin having a curved shape.

[0007] The problems addressed by the present invention are not limited to those mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0008] A vision inspection method for a pin-shaped component according to one embodiment of the present invention for solving the aforementioned problems includes the steps of: fixing the pin-shaped component in an inclined position on the upper surface of an inspection stage; correcting the pin-shaped component to an upright position based on a magnet; rotating the pin-shaped component and photographing the surface of the pin-shaped component; and performing a defect inspection of the pin-shaped component based on a plurality of captured images of the surface of the pin-shaped component.

[0009] In the step in which the pin-shaped component is corrected to an upright position, the magnet moves relative to the pin-shaped component so that the pin-shaped component is corrected to the upright position.

[0010] In the step where the pin-shaped component is corrected to an upright position, the magnet drive unit that moves the magnet is controlled in a PI control manner with the goal of moving the magnet so that the central axis of the magnet and the central axis of the pin-shaped component are coaxial.

[0011] In the step in which the pin-shaped component is corrected to an upright position, the distance M by which the magnet, located below the inspection stage, is moved horizontally toward the pin-shaped component is calculated by the formula M=KX, where K is an experimentally obtained proportionality constant and X is the length of the pin-shaped component projected onto the upper surface of the inspection stage.

[0012] In the step in which the surface of the pin-shaped component is photographed, the relative position of the inspection stage with respect to the rotation drive unit that rotates the inspection stage is adjusted so that the rotation axis of the rotation drive unit and the central axis of the pin-shaped component are aligned.

[0013] The steps of performing the defect inspection include: acquiring a plurality of corrected images in which the pin-shaped component appearing in each of the captured images is changed to a predetermined orientation; extracting target regions in which a part of the pin-shaped component appears in each of the corrected images, and acquiring a merged image by connecting the plurality of target regions to each other; and performing a vision inspection on the merged image.

[0014] In the step where the surface of the pin-shaped component is photographed, the surface of the pin-shaped component is photographed while it is illuminated with light from the lighting module.

[0015] In the step where the merged image is acquired, the extraction target area is identified based on the difference in pixel values ​​between the surface of the pin-shaped component and the background that appears in the modified image due to the influence of light from the lighting module.

[0016] The step of acquiring the modified image includes the steps of distinguishing multiple parts of interest for each of the captured images that appear on the pin-shaped part, acquiring multiple divided images by dividing each of the captured images so that the multiple parts of interest appear on different images, and acquiring multiple modified images in which the parts of interest that appear on each of the divided images are changed to the predetermined posture.

[0017] In the step where the merged image is acquired, the multiple extraction target regions are continuously connected to each other so that they match the actual positions of the pin-shaped components, thereby acquiring the merged image.

[0018] In the step of obtaining the corrected image, the predetermined posture is a posture in which the pin-shaped component is photographed when it is exactly perpendicular to the inspection stage.

[0019] Other specific matters of the present invention are included in the detailed description and the drawings.

Effect of the Invention

[0020] According to an embodiment of the present invention, there are at least the following effects.

[0021] The inspection efficiency for the pogo pin can be maximized.

[0022] The effects of the present invention are not limited to the contents exemplified above, and more diverse effects are included in this specification.

Brief Description of the Drawings

[0023] [Figure 1] It is a diagram schematically showing a pin-shaped component that can be inspected using the vision inspection method for a pin-shaped component according to an embodiment of the present invention. [Figure 2] It is a perspective view of an exemplary non-contact alignment device that can be used in the vision inspection method for a pin-shaped component according to an embodiment of the present invention. [Figure 3] It is an exploded perspective view of the non-contact alignment device shown in FIG. 2. [Figure 4] It is a flowchart for the vision inspection method for a pin-shaped component according to an embodiment of the present invention. [Figure 5] It is a diagram for explaining the principle of adjusting the posture of a pin-shaped component by utilizing a magnet in the present invention. [Figure 6] It is a diagram showing a situation where a pin-shaped component is seated in an inclined posture on an inspection stage. [Figure 7] It is a diagram showing a situation where the pin-shaped component is corrected to a standing posture by the movement of a magnet. [Figure 8] It is a diagram for explaining a method of grasping the horizontal movement distance of a magnet according to an embodiment of the present invention. [Figure 9] This figure illustrates how the X-axis error of an inspection stage is adjusted by a non-contact alignment device according to one embodiment of the present invention. [Figure 10] This figure illustrates how the Y-axis error of an inspection stage is adjusted by a non-contact alignment device according to one embodiment of the present invention. [Figure 11] This figure illustrates the operation of the rotary drive unit of a non-contact type alignment device according to one embodiment of the present invention. [Figure 12] This is a flowchart illustrating the steps involved in performing a defect inspection on a pin-shaped component according to one embodiment of the present invention. [Figure 13] This is a flowchart illustrating the steps for acquiring multiple modified images based on a captured image according to one embodiment of the present invention. [Figure 14] This diagram illustrates how a modified image is obtained based on a single segmented image. [Figure 15] Figure 14 illustrates the process of identifying the extraction target region in the modified image and forming a merged image based on the extraction target region. [Modes for carrying out the invention]

[0024] The advantages and features of the present invention, and methods for achieving them, will become clearer with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and can be embodied in a variety of different forms, and these embodiments are merely provided to complete the disclosure of the present invention and to fully inform those who are ordinary skill in the art to which the invention pertains, of the scope of the invention, and the present invention is defined by the scope of the claims.

[0025] Furthermore, the embodiments described herein are explained with reference to the cross-sectional and / or schematic diagrams which are ideal illustrative diagrams of the present invention. Therefore, the form of the illustrative diagrams may be modified due to manufacturing techniques and / or tolerances. Also, each component in each drawing of the present invention is shown slightly enlarged or reduced for the sake of explanation. Throughout the specification, the same reference numerals refer to the same component.

[0026] Furthermore, the directions "up / down / front / back / left / right" mentioned below are illustrative directions explained based on a single reference point to facilitate understanding of the invention. Therefore, the present invention is not construed as being limited to the methods described below. That is, the directions may differ from those mentioned below during the actual use of the present invention, and the present invention is construed as including such modified embodiments.

[0027] On the other hand, the pin-shaped components mentioned below can refer to components that have a long pin shape. Furthermore, pin-shaped components may include magnetic materials that are magnetized by a magnetic field. One example of a pin-shaped component is a pogo pin.

[0028] The present invention will be described below with reference to drawings illustrating a vision inspection method for pin-shaped components according to embodiments of the present invention.

[0029] Before describing the vision inspection method for pin-shaped components according to an embodiment of the present invention, we will first describe the pin-shaped component to be inspected and the apparatus that can be used to perform the vision inspection method for pin-shaped components according to an embodiment of the present invention.

[0030] Figure 1 is a schematic diagram showing a pin-shaped component that can be inspected using a vision inspection method for pin-shaped components according to one embodiment of the present invention.

[0031] As shown in Figure 1, the pin-shaped component is a pogo pin. The pogo pin 1000 is configured in an overall cylindrical shape, and its curved side surface, as well as its top and bottom surfaces, require inspection. In particular, because the side surface is curved, the pogo pin 1000 must be rotated 360 degrees while being inspected for side surface inspection.

[0032] The pogo pin 1000 can be distinguished by its shape into a lower section 1001, a middle section 1002, and an upper section 1003. Each of the lower section 1001, middle section 1002, and upper section 1003 may have a roughly circular shape. The lower section 1001 has a smaller diameter than the middle section 1002 and may extend to a shorter length (length in the height direction) than the middle section 1002. The middle section 1002 may have the largest diameter and longest length within the pogo pin 1000. The upper section 1003 is the part of the pogo pin 1000 with a relatively small diameter and the shortest length. However, the shape of the pogo pin 1000 is not necessarily limited to the examples given.

[0033] A vision camera module can be used for visual inspection of the Pogo Pin 1000. When rotating the Pogo Pin 1000 for side inspection, the accuracy of the visual inspection can be maximized if two conditions are met: firstly, the Pogo Pin 1000 is uprightly erect in the invertical direction, and secondly, the central axis of the Pogo Pin 1000 and the rotational axis that rotates the Pogo Pin 1000 are coaxial.

[0034] To satisfy the two conditions mentioned above, mechanical alignment can be considered, but the outer surface may be obstructed by the alignment device (e.g., a gripper). In particular, when the pogo pin 1000 is small in size, a disadvantage may arise in that the proportion of the outer surface obstructed by the aforementioned gripper becomes large. Also, if the end of the device is made sharp in order to minimize the area of ​​the outer surface of the pogo pin 1000 that is obstructed by the device, damage to the pogo pin 1000 due to stress concentration may occur.

[0035] Therefore, the method according to one embodiment of the present invention uses a device that can change the orientation of the pogo pins 1000 in a non-contact manner and align them. On the other hand, although the following description assumes that the pin-shaped component 1000 that is the subject of the present invention is a "pogo pin", the subject of the present invention is not limited to pogo pins, but can be any pin-shaped component that is made of a magnetic material and has a long shape.

[0036] Furthermore, the method according to one embodiment of the present invention will be described below on the premise that the pogo pins are aligned and photographed while rotating in order to inspect the side and top of the pogo pins.

[0037] For this purpose, the method according to one embodiment of the present invention can utilize a non-contact attitude alignment device, a vision camera module, a lighting module, and an information processing device.

[0038] A non-contact orientation alignment device can be configured to align the orientation of pin-shaped parts based on magnets. Specifically, a non-contact orientation alignment device can include an inspection stage on which pin-shaped parts can be fixed and maintain their fixed orientation, a magnet that is movable relative to the inspection stage, and a rotary drive unit that rotates the inspection stage and is movable relative to the inspection stage. In this case, each component of the non-contact orientation alignment device can be implemented in various ways using conventionally known technologies.

[0039] The vision camera module can be selected from at least one of the various camera modules conventionally used for visual inspection.

[0040] The lighting module can include a variety of conventionally known lighting to embody the method. For example, the lighting module may include a coaxial lighting module installed to be coaxial with the vision camera module, and a backlight module formed to form the background of the inspection stage.

[0041] On the other hand, the information processing device is a conventionally known computer device that can be configured to control a non-contact attitude alignment device, a vision camera module, and a lighting module. Furthermore, the information processing device is configured to communicate with the vision camera module, receive images captured by the vision camera module, and perform defect inspection based on those images. In this case, conventionally known algorithms or programs can be used for defect inspection, and such algorithms or programs can be non-temporarily recorded in the information processing device.

[0042] Hereinafter, with reference to Figures 2 and 3, examples of non-contact alignment devices that can be used in the method according to one embodiment of the present invention will be described. Figure 2 is a perspective view of an exemplary non-contact alignment device that can be used in the vision inspection method for pin-shaped parts according to one embodiment of the present invention. Figure 3 is an exploded perspective view of the non-contact alignment device shown in Figure 2.

[0043] Referring to Figures 2 and 3, a non-contact alignment device 1 according to one embodiment of the present invention can be configured to include a fixing part 100, a body part 300, a magnet 400, a position adjustment part 500, a position alignment part 600, and a rotation drive part 640.

[0044] The anchoring portion 100 can be configured so that a pogo pin 1000 can be anchored to its upper surface. In a vision inspection method for pin-shaped components according to one embodiment of the present invention, the anchoring portion 100 performs the role of an inspection stage. The upper surface of the anchoring portion 100 may be provided with an anchoring surface 110 configured to prevent the anchored pogo pin 1000 from slipping. For example, the anchoring surface 110 may have a high coefficient of friction or a recessed groove that can accommodate the end of the pogo pin 1000. The pogo pin 1000 anchored to the anchoring portion 100 can maintain its orientation with a magnet 400, described later, with its lower portion in contact with the anchoring portion 100. While anchored to the anchoring surface 110, the pogo pin 1000 can be positioned vertically upright or slightly tilted.

[0045] A recognition unit 200 may be provided around the attachment surface 110 of the attachment part 100. The recognition unit 200 can be configured in a predetermined geometric shape. For example, the recognition unit 200 can be formed as a polygon. The recognition unit 200 may be configured to include corners so that it is easily recognized in the captured image when captured by the vision camera module from vertically above or to the side. Therefore, during visual inspection, the recognition unit 200 can be easily excluded from the image captured by the vision camera module. In other words, the recognition unit 200 makes it easy to identify the area in the image where the attachment part 100 and pogo pins 1000 appear.

[0046] The body portion 300 is coupled to the lower side of the anchoring portion 100, and a space can be formed inside it in which a magnet 400, described later, can be provided. The space inside the body portion 300 can be provided in a size that allows the magnet 400 to move a predetermined distance horizontally. The bottom surface of the body portion 300 can be fixed to the first frame 610 located at the uppermost side of the position alignment portion 600.

[0047] The magnet 400 is configured to correct the orientation of the pogo pin 1000. The magnet 400 can be installed inside the body 300 so that it is initially positioned vertically below the anchoring part 100. The magnet 400 can have sufficient magnetic force to reach the pogo pin 1000 anchored to the upper side of the recognition part 200. The magnet 400 can be configured, for example, in the shape of a disc, with the upper and lower parts having opposite polarities.

[0048] A magnet holder (not shown) is configured so that its center can connect with the magnet 400 and so that it can move horizontally within the body 300. In this case, the upper end of the magnet holder (not shown) can be in close contact with the ceiling of the internal space of the body 300 and so that it can slide against the inner wall of the body 300.

[0049] The position adjustment unit 500 can be configured to adjust the horizontal position of the magnet 400. Here, the horizontal direction can mean the direction in which the magnet 400 slides relative to the flat bottom of the internal space of the body 300. For ease of understanding, assuming that the bottom of the internal space of the body 300 is the XY plane, the horizontal direction is a vector on the XY plane. When the horizontal position of the magnet 400 is changed by the position adjustment unit 500, the magnetic field can be changed. This changes the direction of the magnetic force acting on the pogo pin 1000, and thereby changes the orientation of the pogo pin 1000. On the other hand, as mentioned above, when adjusting the orientation (or angle) of the pogo pin 1000 by adjusting the horizontal position of the magnet 400, the lower part of the pogo pin 1000 can maintain contact with the anchoring part 100 without slipping.

[0050] The position adjustment unit 500 may include a first position adjustment unit 511 configured to adjust the position of the magnet 400 in the X-axis direction within the body unit 300, and a second position adjustment unit 521 configured to adjust the position in the Y-axis direction. The first position adjustment unit 511 is positioned across the X-axis direction on the side wall of the body unit 300, and its end can support the magnet 400 or a magnet holder. In this case, the position of the first position adjustment unit 511 can be adjusted in the X-axis direction by a drive unit 512 for the first position adjustment unit.

[0051] The length of the first position adjustment section 511 inserted into the body section 300 can be adjusted. In this case, the position of the magnet 400 in the X-axis direction can be changed according to the length of the first position adjustment section 511 inserted into the body section 300. On the other hand, a first elastic section 513 may be provided on the opposite side of the first position adjustment section 511 with respect to the magnet 400. The first elastic section 513 can be configured to transmit force to the magnet 400 on the side of the first position adjustment section 511. Therefore, the magnet 400 receives a force from the first elastic section 513 that causes it to adhere tightly to the end of the first position adjustment section 511. In the end, the position of the magnet 400 in the X-axis direction is adjusted according to the insertion length of the first position adjustment section 511, and when the first position adjustment section 511 retracts, it can move along the first position adjustment section 511 due to the elastic force.

[0052] The second position adjustment section 521 is configured to press the magnet 400 along the Y-axis direction. The second position adjustment section 521 can be configured similarly to the first position adjustment section 511 and can be positioned perpendicular to the first position adjustment section 511. The length of the second position adjustment section 521 that protrudes in the Y-axis direction can be adjusted by the drive section 522 of the second position adjustment section. The second elastic section 523 can be positioned on the opposite side of the second position adjustment section 521 from the magnet 400. The function of the second elastic section 523 is similar to that of the first elastic section 513, and the direction of the force acting on it can be in the Y-axis direction.

[0053] In the above description, it was explained that the first position adjustment part 511, the second position adjustment part 521, the first elastic part 513, and the second elastic part 523 transmit force or change position by directly contacting the magnet 400. However, the configuration may be modified to transmit force by contacting a magnet holder (not shown).

[0054] The position alignment unit 600 can be configured to align the central axis of the pogo pin 1000 with the rotation axis of the inspection stage after the pogo pin 1000 has been positioned vertically by the position adjustment unit 500. Because the pogo pin 1000 is a small part, when it is attached to the attachment unit 100, it may be slightly off from the center of the attachment unit 100. Also, when the angle of the pogo pin 1000 is adjusted by the magnet 400, it may slip slightly or be rotated due to the shape of the lower end of the pogo pin 1000, causing the contact position with the upper surface of the attachment unit 100 to change. In other words, each time the pogo pin 1000 is attached, its position is not constant, and its position may change even during the posture correction process. At this time, when the inspection stage is rotated on a fixed rotation axis, the pogo pin 1000 can perform circular motion around the rotation axis. If the pogo pin 1000 begins to move in a circular motion, it becomes difficult to obtain an accurate inspection image, and the accuracy of the inspection may decrease. To solve this problem, the position alignment unit 600 is configured to align the central axis and rotational axis of the fixed pogo pin 1000 by horizontally moving the body unit 300.

[0055] The position alignment unit 600 may include a first frame 610, a first frame drive unit 611, a second frame 620, a second frame drive unit 621, a third frame 630, a base 650, and a rotation drive unit 640.

[0056] The first frame 610 can be configured to be movable relative to the second frame 620 in the X-axis direction. The upper part of the first frame 610 can be coupled to the lower part of the body 300. The first frame 610 can be connected to the second frame 620 by a means of constraint on the direction of movement, such as a linear guide, so that it can move only in the X-axis direction. The first frame drive unit 611 is installed in the X-axis direction so that the position of the first frame 610 in the X-axis direction on the second frame 620 can be adjusted.

[0057] The second frame 620 can be configured to be movable relative to the third frame 630 in the Y-axis direction. The second frame 620 can be connected to the third frame 630 by a means of constraint on the direction of movement, such as a linear guide. The second frame drive unit 621 can be configured to adjust the position of the second frame 620 in the Y-axis direction.

[0058] The third frame 630 can be configured to rotate relative to the base 650 of the rotary drive unit 640. The rotary drive unit 640 can generate a driving force that can rotate the third frame 630. For example, a coupling member that rotates the third frame 630 can be positioned on the upper surface of the base 650. The coupling member is configured to be rotatable on the upper surface of the base 650 by the power of the rotary drive unit 640 and can be coupled to the bottom surface of the third frame 630. On the other hand, the lower part of the base 650 can be coupled to an external structure. In this case, the order of the first frame 610 and the second frame 620 described above may be reversed.

[0059] The first frame 610, the first frame drive unit 611, the second frame 620, and the second frame drive unit 621 are configured to rotate together with the third frame 630. Therefore, when the position of the body 300 in the X and Y directions is adjusted by the first frame 610 and the second frame 620, the rotation radius of the pogo pins 1000 is also adjusted. In short, the non-contact alignment device 1 can adjust the position of the device's rotation axis relative to the pogo pins 1000 in the X and Y directions. This makes it possible for the non-contact alignment device 1 to ultimately align the rotation center axis of the first frame 610 with the center axis of the pogo pins 1000.

[0060] The following describes a vision inspection method for pin-shaped components according to one embodiment of the present invention, with reference to the explanation above and Figures 4 to 15. Figure 4 is a flowchart of the vision inspection method for pin-shaped components according to one embodiment of the present invention.

[0061] As shown in Figure 4, a vision inspection method for a pin-shaped component according to one embodiment of the present invention may include the steps of: securing the pin-shaped component to an inspection stage (S100); adjusting the relative position of the inspection stage with respect to a rotary drive unit (S200); correcting the pin-shaped component to an upright position (S300); photographing the surface of the pin-shaped component (S400); and performing a defect inspection on the pin-shaped component (S500).

[0062] In step (S100), where the pin-shaped component is secured to the inspection stage, a gripper or a transfer device capable of picking up and placing the pin-shaped component like a gripper can place the pin-shaped component on the inspection stage. At this time, the inspection stage can be represented by various devices or components that can support the pin-shaped component in the position where it has been placed by the transfer device. In the example of the non-contact alignment device described above, the securing part plays such a role.

[0063] In step (S200), in which the relative position of the inspection stage with respect to the rotary drive unit is adjusted, the position of the inspection stage can be adjusted so that the lower part of the pin-shaped component is located on the rotation axis of the rotary drive unit that rotates the inspection stage. For this purpose, the inspection stage can be provided in a manner that allows for relative position adjustment with respect to the rotary drive unit. For example, the inspection stage can be adjusted in the X-axis and Y-axis directions with respect to the rotary drive unit, as in the mounting part of the non-contact type alignment device described above.

[0064] When this step (S200) is completed, the lower part of the pin-shaped component is positioned on or adjacent to the rotation axis of the rotary drive unit. Therefore, when this step (S200) is completed, the contact point between the pin-shaped component and the inspection stage can be positioned on or adjacent to the rotation axis of the rotary drive unit.

[0065] In this step (S200), the current position of the pin-shaped component can be determined using a backlight module and a vision camera module. For example, in this step (S200), the current position of the pin-shaped component can be determined based on a position confirmation image taken from the side of the pin-shaped component with the backlight module located behind the pin-shaped component illuminated. At this time, the pin-shaped component will appear dark in the position confirmation image due to the light from the backlight module, and its silhouette will be clearly visible.

[0066] An information processing device that receives a position confirmation image can determine the position and / or coordinates of the contact or lower end of the pin-shaped component. For example, the current positions of the inspection stage and the rotation axis of the rotary drive unit can be accurately determined based on the operation information for the device. Therefore, if only the position of the pin-shaped component on the inspection stage is determined via the position confirmation image, it is possible to determine not only the current position of the pin-shaped component but also the amount of movement required to move the inspection stage in order to position the contact of the pin-shaped component on the rotation axis.

[0067] At this time, in order to determine the X-axis and Y-axis movement amounts of the inspection stage, the position confirmation image may include an X-axis movement amount image to determine the X-axis movement amount and a Y-axis movement amount image to determine the Y-axis movement amount. The two images can be captured by vision camera modules positioned so as to look perpendicular to each other with the inspection stage as the center. Alternatively, the two images can be captured by a single vision camera module, by rotating the inspection stage 90 degrees between the capture of the first image and the capture of the second image.

[0068] In step (S300), where the pin-shaped component is corrected to an upright position, the component can be corrected to an upright position based on the magnet. At this time, the upright position is a position in which the central axis of the pin-shaped component is at an angle that is nearly perpendicular to the inspection stage. The transfer device can transfer the pin-shaped component to the inspection stage in a position as close to upright as possible. However, securing the pin-shaped component to the inspection stage in a perfectly vertical position from the beginning is not only difficult to control the transfer device, but can also require a long time. Furthermore, even if the inspection stage holds the lower part of the pin-shaped component by magnetic force or other known methods, the inspection stage itself moves in the previous step (S200), which can transmit minute vibrations to the pin-shaped component. Due to such vibrations, the position of the pin-shaped component may twist even if it is initially loaded perpendicularly onto the inspection stage.

[0069] According to the present invention, in the step (S100) in which the pin-shaped component is secured to the inspection stage, the transfer device places the pin-shaped component in an inclined position, making it possible to load the pin-shaped component onto the inspection stage in a short time. Subsequently, in this step (S300), the pin-shaped component can be corrected to an upright position by moving relative to the pin-shaped component with a magnet located at the bottom of the inspection stage.

[0070] Therefore, according to the present invention, a pin-shaped component in an upright position can be quickly prepared on the inspection stage, and damage to the pin-shaped component during the process of preparing it in an upright position can be minimized.

[0071] On the other hand, in the step (S400) in which the surface of the pin-shaped component is photographed, the vision camera module can start photographing while the pin-shaped component is rotating. For this purpose, the vision camera module can be positioned on one side of the inspection stage to view the side of the pin-shaped component. The vision camera module can continuously photograph the side of the pin-shaped component while it is rotating. Alternatively, the pin-shaped component can be rotated by a predetermined angle at a time, and the vision camera module can photograph the surface of the pin-shaped component while it is stationary for a period of time.

[0072] Furthermore, this step (S400) can be carried out with light from the illumination module illuminating the surface of the pin-shaped component. At this time, the illumination module can be provided as a coaxial illumination module for the vision camera module so that light is illuminating the portion of the surface of the pin-shaped component that the vision camera module has focused on.

[0073] In step (S500), in which a defect inspection of a pin-shaped component is performed, the defect inspection of the pin-shaped component can be performed based on an image captured from the surface of the pin-shaped component. At this time, the program that searches for defects set within the image has been disclosed in the past, so its explanation will be omitted. This step (S500) can be performed by an information processing device that receives the captured image and processes the image into the required format.

[0074] Hereinafter, with reference to Figure 5, a vision inspection method for a pin-shaped component according to one embodiment of the present invention will be described, specifically a method for correcting the orientation of a pin-shaped component 1000 using a magnet 400. Figure 5 is a diagram illustrating the principle of adjusting the orientation of a pin-shaped component using a magnet in the present invention. In one embodiment of the present invention, a magnet 400 having a disc shape can be used. The pin-shaped component 1000 can receive magnetic force in different directions depending on its relative position from the center of the magnet 400.

[0075] At the center of magnet 400, magnetic field lines can appear in a generally vertical direction. The further away from the center of the magnet, the greater the inclination of the magnetic field lines (AA1, AA2). Therefore, by adjusting the relative position of the center of magnet 400 and the pin-shaped component 1000, the direction of the magnetic field lines acting on the pin-shaped component 1000 can be changed, thereby allowing for non-contact adjustment of the orientation (angle) of the pin-shaped component 1000.

[0076] At this time, for the pin-shaped component 1000 to be in an upright position, the central axis of the magnet 400 and the central axis of the pin-shaped component 1000 must be coaxial. Therefore, in the step (S300) in which the pin-shaped component is corrected to an upright position, the magnet drive unit that moves the magnet 400 can move the magnet 400 with the goal of making the central axis of the magnet 400 and the central axis of the pin-shaped component 1000 coaxial. At this time, the magnet drive unit can be controlled by an information processing device or a corresponding control device using a PI control (Proportional Integral control) method with the goal of positioning the magnet 400 as described above. On the other hand, in the non-contact type alignment device described above, the magnet drive unit corresponds to the position adjustment unit.

[0077] The following describes the movement of the magnet 400 relative to the inspection stage IS in step (S300) in which a pin-shaped component according to one embodiment of the present invention is corrected to an upright position, with reference to Figures 6 to 7. Figure 6 shows the pin-shaped component settled on the inspection stage in an inclined position. Figure 7 shows the pin-shaped component corrected to an upright position by the movement of the magnet.

[0078] As shown in Figure 6, initially the pin-shaped component 1000 can be attached to the inspection stage IS in a generally tilted position. At this time, due to the frictional force of the inspection stage IS or the magnetic force of the magnet 400, the lower end of the pin-shaped component 1000 is placed on the axis of rotation, so even after the inspection stage IS moves, the position of the pin-shaped component 1000 remains the same as or similar to the initial attachment position. In this case, the tilted position is a position where the angle between the inspection stage IS and the pin-shaped component 1000 is not right angle.

[0079] On the other hand, the PI-controlled magnet drive unit allows the magnet 400 to move so that it is positioned directly below the contact point between the pin-shaped component 1000 and the inspection stage IS, as shown in Figure 7. In this state, the magnetic field lines from the magnet 400 are in a vertical direction, so the pin-shaped component 1000 is corrected to an upright position.

[0080] The following describes how the information processing device determines the distance the magnet moves horizontally, with reference to Figure 8. Figure 8 is a diagram illustrating a method for determining the horizontal movement distance of a magnet according to one embodiment of the present invention. As mentioned above, in order for the pin-shaped component 1000 to be converted to an upright position, the center of the magnet 400 must be located directly below the contact point between the pin-shaped component 1000 and the inspection stage. In this state, the central axis of the magnet 400 and the central axis of the pin-shaped component 1000 can be located coaxially with each other.

[0081] The information processing device calculates the distance M required to move the magnet 400 horizontally directly below the pin-shaped component 1000 in order to move the magnet 400 as described above.

[0082] At this time, the travel distance M can be calculated using the formula M = KX. Here, K is an experimentally obtained proportionality constant, and X is the length X of the pin-shaped part 1000 projected onto the upper surface of the inspection stage, which is also represented as X in Figure 8. At this time, the length of the pin-shaped part 1000 is pre-recorded in the information processing device, and the information processing device can calculate X based on the pre-recorded length and the angle AA3 between the inspection stage and the pin-shaped part 1000. More specifically, the information processing device can calculate X by multiplying the length of the pin-shaped part 1000 by the cosine AAS value.

[0083] On the other hand, the angle AAS can be calculated through the following process.

[0084] First, in step (S300) in which the pin-shaped component is corrected to an upright position, the backlight module facing the vision camera module across the inspection stage can be switched ON before the correcting of the position. The backlight module is provided in a size large enough that its front surface can form the background of the pin-shaped component 1000 when photographed by the vision camera module, and is configured so that light is emitted from the front. Hereinafter, the image of the pin-shaped component 1000 photographed by the vision camera module with the backlight module emitting light will be referred to as the position confirmation image.

[0085] In the posture confirmation image, the pin-shaped component 1000 appears very dark against the background due to backlighting from the backlight module. A characteristic of the posture confirmation image is that the boundary between the background and the pin-shaped component 1000 is very clear. The information processing device recognizes the boundary line of the pin-shaped component 1000 in the posture confirmation image and calculates the center coordinates of the boundary line, thereby determining the central axis of the pin-shaped component 1000. Once the central axis of the pin-shaped component 1000 is determined, the information processing device can determine the angle AA3 that the central axis of the pin-shaped component 1000 has with respect to the inspection stage on the posture confirmation image.

[0086] Subsequently, the information processing device can calculate the distance traveled M using the captured angle AA3, the previously recorded length, and the previously recorded proportionality constant (K). The reason for calculating the distance traveled M as the product of K and X is as follows:

[0087] Specifically, the distance traveled M is equal to the difference between the horizontal straight-line distance (D) from the point of weight of the magnet 400 to the upper end of the pin-shaped component 1000 and the length X of the projected pin-shaped component 1000. In other words, M is equal to the value obtained by subtracting X from D.

[0088] Furthermore, using the similarity property of triangles, the ratio of X to D is the same as the ratio of the height of the pin-shaped component (H1) to the height difference (H2) from the top of the pin-shaped component 1000 to the point of weight of the magnet 400 when tilted. That is, X to D is the same ratio as H1 to H2. Therefore, X can be expressed as a value obtained by multiplying D by a predetermined constant. Using this property, the equation for M can be expressed as the product of X and an appropriate constant K. In this case, K is obtained experimentally, and a more appropriate K can be secured by conducting experiments after appropriately setting the range of angle AA3 in which the pin-shaped component 1000 mainly adheres to the inspection stage.

[0089] On the other hand, in the step (S300) in which the pin-shaped component is corrected to an upright position, after changing the position of the magnet 400, the system can take another orientation confirmation image to confirm whether the pin-shaped component 1000 has been properly corrected to an upright position. When the pin-shaped component 1000 is properly corrected to an upright position, the information processing device can switch the backlight module to the OFF state and drive the rotation drive unit to rotate the inspection stage. At this time, the determination of whether the component has been properly corrected to an upright position can be made by checking whether the angle of the central axis of the pin-shaped component 1000 in the orientation confirmation image is within a predetermined range with vertical as the intermediate value.

[0090] The following describes examples of how the inspection stage moves to position pin-shaped components on the rotation axis, with reference to Figures 9 to 11. Figure 9 illustrates how the X-axis error of the inspection stage is adjusted by a non-contact alignment device according to one embodiment of the present invention. Figure 10 illustrates how the Y-axis error of the inspection stage is adjusted by a non-contact alignment device according to one embodiment of the present invention. Figure 11 illustrates the operation of the rotary drive unit of the non-contact alignment device according to one embodiment of the present invention.

[0091] In this case, Figures 9 to 10 illustrate the adjustment of the X-axis error followed by the Y-axis error, but the reverse is also possible. Furthermore, in Figures 9 and 10, after the errors with respect to the X-axis and / or Y-axis have been adjusted, the orientation of the pin-shaped component can be corrected by a magnet before the rotary drive unit rotates, as shown in Figure 11.

[0092] After the pin-shaped component moves along the X-axis or Y-axis and its orientation is corrected, the information processing device moves the inspection stage in the direction of the X-axis or Y-axis so that the central axis of the pin-shaped component and the rotation axis of the rotation drive unit become coaxial, thereby positioning the contact point of the pin-shaped component on the rotation axis.

[0093] For example, the information processing device can determine the X-axis and Y-axis movement amounts based on the aforementioned X-axis movement amount images and Y-axis movement amount images. Since this has been explained previously, a redundant explanation will be omitted. As another example, the information processing device can determine the amount of position adjustment relative to the inspection stage using a top-view image captured by a vision camera module positioned above the inspection stage. Specifically, the information processing device can first determine the X and Y coordinates where the contacts of the pin-shaped component are located on the top-view image, and then calculate the amount of movement of the first frame 610 and the second frame 620 to position the pin-shaped component on the rotation axis of the rotary drive unit 640. At this time, since the rotation axis position of the rotary drive unit 640 is always fixed, the X and Y coordinates of the rotation axis can be accurately measured on the position confirmation image or top-view image and recorded in advance in the information processing device.

[0094] Once the rotation drive unit 640 and the pin-shaped component are aligned and the orientation of the pin-shaped component is corrected, the third frame 630 is rotated as shown in Figure 11, and surface imaging of the side of the pin-shaped component can begin.

[0095] The steps that may be included in the step (S500) for performing a defect inspection on a pin-shaped component according to one embodiment of the present invention will be described below with reference to Figure 12. Figure 12 is a flowchart of the steps for performing a defect inspection on a pin-shaped component according to one embodiment of the present invention.

[0096] As shown in Figure 12, the step (S500) of performing a defect inspection on a pin-shaped component according to one embodiment of the present invention may include the steps of acquiring a plurality of corrected images based on the captured image (S510), acquiring a merged image in which the target extraction region is extracted from the corrected images and the extracted target regions are linked together (S520), and performing a vision inspection on the merged image (S530).

[0097] In step S510, in which multiple corrected images are acquired based on the captured image, a corrected image can be acquired in which the pin-shaped component appearing in the captured image is changed to a predetermined orientation. The corrected image can be performed for each of the captured images. At this time, each captured image was taken when the rotation angle of the pin-shaped component was different from that of the other captured images. On the other hand, the predetermined orientation is the orientation captured when the pin-shaped component is exactly perpendicular to the inspection stage.

[0098] In the previous step, even if the pin-shaped component is changed to its most upright position using a magnet, it is practically difficult for the pin-shaped component to form a perfect right angle with respect to the inspection stage. In this step (S510), the pin-shaped component appearing in the captured image is rotated through the image processing of the information processing device, thereby obtaining a corrected image in which the pin-shaped component is represented in a precisely vertical position.

[0099] In step S520, where the target region is extracted from the corrected image and a merged image is obtained by linking the target regions together, a portion of the pin-shaped component can be extracted as the target region within the corrected image. At this time, the portion is the part located in the middle of the vertically transformed image of the pin-shaped component, and is the part that was illuminated with concentrated light during the shooting process.

[0100] A merged image is an image formed by sequentially concatenating the extraction target regions, each extracted based on different captured images. For example, an information processing device can obtain a single merged image by concatenating the extraction target regions according to the order in which the captured images that formed the basis of the extraction were taken. In a merged image formed in this way, each extraction target region can be positioned to match the actual position of the pin-shaped component, and the merged image can be obtained as an image of the pin-shaped component's side view unfolded.

[0101] On the other hand, the extraction target area can be recognized based on the difference in pixel values ​​between the pin-shaped component and the background in the corrected image, due to the influence of light from the lighting module. This will be explained later with reference to Figure 15.

[0102] On the other hand, in the step (S530) in which a vision inspection of the merged image is performed, defects appearing in the merged image can be identified by the information processing device. Defects are those that should not be present on the appearance of the pin-shaped component, such as foreign objects, scratches, and indentations, and can be pre-set. For this purpose, the information processing device can have an algorithm or program pre-recorded in it that determines the presence and type of defects based on the pixel value of each pixel in the merged image and the shape appearing in the merged image.

[0103] The following describes steps that may be included in the step (S510) in which multiple corrected images are acquired based on the captured image, with reference to Figure 13. Figure 13 is a flowchart of the step in which multiple corrected images are acquired based on the captured image according to one embodiment of the present invention.

[0104] As shown in Figure 13, the step (S510) of acquiring a plurality of modified images based on a captured image according to one embodiment of the present invention may include the step (S511) of distinguishing a plurality of areas of interest that appear in the captured image, the step (S512) of acquiring a plurality of divided images obtained by dividing the captured image so that each area of ​​interest appears on a different image, and the step (S513) of acquiring a plurality of modified images in which the areas of interest are changed to a predetermined posture.

[0105] In the step (S511) in which multiple areas of interest appearing in the captured image are distinguished, multiple areas of interest can be recognized and distinguished from a single captured image. Furthermore, referring to Figure 1, the areas of interest can be set as the lower section 1001, the middle section 1002, and the upper section 1003. The information processing device can be set to distinguish these based on the shape characteristics of the lower section 1001, the middle section 1002, and the upper section 1003 that appear in the captured image.

[0106] For example, first, the information processing device recognizes pixels located at the boundaries of a pin-shaped component that appears in the captured image, and by calculating the intermediate coordinates of the pixels located at both ends of the boundary, it can determine the central axis of the pin-shaped component. Subsequently, the information processing device recognizes the point where the pixel distance between pixels at the boundary changes abruptly from the central axis as the boundary of the area of ​​interest, and can distinguish the lower section 1001, the middle section 1002, and the upper section 1003 in the captured image. At this time, the pixel distance can be determined by the distance calculated based on the coordinate values ​​of the pixels for two pixels, or by the number of pixels located between the two pixels.

[0107] Alternatively, as another example, since the captured image is usually taken after the pin-shaped component has been converted to an upright position, the information processing device can pre-record information for each region of interest in the area where it appears in the captured image. For example, the information processing device may pre-record the coordinate ranges in which the upper section 1003, middle section 1002, and lower section 1001 appear in the captured image, and the information processing device can distinguish each region based on the pre-recorded coordinate ranges. In this case, the coordinate range is, for example, the coordinate range with respect to the vertical axis on the image.

[0108] In step S512, multiple segmented images are acquired by dividing the captured image so that each region of interest appears on a different image. In this step, new segmented images can be formed for each region of interest that was distinguished in the previous step. The multiple segmented images are acquired by cutting the boundaries of the regions of interest on the captured image. Therefore, based on the example described above, one captured image is divided into segmented images for the upper section 1003, segmented images for the middle section 1002, and segmented images for the lower section 1001.

[0109] In step (S513), multiple modified images are acquired in which the region of interest is changed to a predetermined posture. Each segmented image is processed to change the posture of the region of interest that appears in the segmented image to the predetermined posture. After this step, multiple modified images are acquired in which the region of interest is represented in a vertical posture for each region of interest.

[0110] Continuing the explanation with reference to Figure 14, Figure 14 illustrates how a modified image is obtained based on a single segmented image.

[0111] In Figure 14, the region of interest (the bright area in the middle of the image) that appears in the segmented image I1 is initially slightly tilted. For example, as explained above, the information processing device can use pixels located at the boundary of the region of interest to find the central axis of the region of interest, and then process the image so that the central axis is perpendicular to obtain the corrected image I2.

[0112] Continuing the explanation with reference to Figure 15, Figure 15 illustrates the process of identifying the extraction target region in the modified image of Figure 14 and forming a merged image based on the extraction target region.

[0113] The information processing device can first identify the central axis of the region of interest that appears in the modified image I2. Then, the information processing device can set a set of pixels within a predetermined horizontal pixel distance from the central axis as the extraction target region I3. The images of the extracted extraction target region I3 are then arranged and concatenated sequentially according to their shooting order, thereby acquiring a single merged image I4. Therefore, the merged image I4 can resemble an image of a pin-shaped component after its region of interest has been cut in the height direction and then unfolded.

[0114] On the other hand, after forming a segmented image according to the embodiment, defect calculation for each region of interest can also be implemented by different information processing devices. For example, multiple different information processing devices can each receive segmented images for different regions of interest, then independently process the segmented images to obtain corrected images, form a merged image, and finally detect defects in the merged image. In this case, the computational burden on a single information processing device is reduced, enabling faster inspection of pin-shaped components. However, this is merely an example, and it is also possible for a single information processing device to perform all steps.

[0115] A person with ordinary skill in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without altering its technical idea or essential features. Therefore, the embodiments described above should be understood to be illustrative and not limiting in all respects. The scope of the present invention is defined by the claims, which are set forth below rather than in the detailed description above, and all modifications or altered forms derived from the meaning and scope of the claims and the concept of equivalents thereto should be interpreted as being included within the scope of the present invention. [Explanation of Symbols]

[0116] 1. Non-contact sorting device 100 Safeguards 110 Seat surface 200 Recognition section 300 Body part 400 magnets 500 Position adjustment section 600 Position Alignment Section 610 First frame 620 Second Frame 630 Third Frame 640 Rotary drive unit 650 base 1000 Pogo Pins / Pin-shaped Components 1001 Lower section 1002 Middle section 1003 Upper section IS Inspection Stage I1 Split Image I2 Revised Image I3 Extraction Target Area I4 Merger Image

Claims

1. A step in which a pin-shaped component is secured to the upper surface of the inspection stage in an inclined position; A step in which the pin-shaped component is corrected to an upright position based on the magnet; The pin-shaped component is rotated and the surface of the pin-shaped component is photographed; and, A vision inspection method for a pin-shaped component, comprising the step of performing a defect inspection on the pin-shaped component based on a plurality of captured images of the surface of the pin-shaped component.

2. In the step in which the pin-shaped component is corrected to an upright position, The method for visual inspection of a pin-shaped component according to claim 1, wherein the magnet moves relative to the pin-shaped component so that the pin-shaped component is corrected to the upright position.

3. In the step in which the pin-shaped component is corrected to an upright position, The method for visual inspection of a pin-shaped component according to claim 2, wherein the magnet drive unit that moves the magnet is controlled in a PI control manner with the aim of moving the magnet so that the central axis of the magnet and the central axis of the pin-shaped component are coaxial.

4. In the step in which the pin-shaped component is corrected to an upright position, The method for visual inspection of a pin-shaped component according to claim 2, wherein the distance M by which the magnet located below the inspection stage is moved horizontally toward the pin-shaped component is calculated by the formula M = KX, where K is an experimentally obtained proportionality constant and X is the length of the pin-shaped component projected onto the upper surface of the inspection stage.

5. Prior to the step in which the surface of the pin-shaped component is photographed, A method for visual inspection of a pin-shaped component according to claim 1, further comprising the step of adjusting the relative position of the inspection stage with respect to a rotary drive unit such that the lower portion of the pin-shaped component is located on the axis of rotation of the rotary drive unit that rotates the inspection stage.

6. The step in which the aforementioned defect inspection is performed is: A step is taken in which multiple corrected images are obtained in which the pin-shaped component that appeared in each of the aforementioned captured images is changed to a predetermined orientation; A step in which, in each of the aforementioned modified images, the target region in which a part of the pin-shaped component appears is extracted, and a merged image is obtained by connecting the multiple target regions to each other; and, A method for visual inspection of a pin-shaped component according to claim 1, comprising the step of performing a vision inspection on the merged image;

7. In the step in which the surface of the pin-shaped component is photographed, The vision inspection method for a pin-shaped component according to claim 6, wherein the surface of the pin-shaped component is photographed while the pin-shaped component is illuminated with light from a lighting module.

8. In the step where the merged image is obtained, The method for visual inspection of a pin-shaped component according to claim 7, wherein the extraction target area is identified based on the difference in pixel values ​​between the surface of the pin-shaped component and the background that appears in the corrected image due to the influence of light from the lighting module.

9. The step in which the aforementioned modified image is obtained is: A step in which multiple areas of interest are distinguished for each of the aforementioned captured images of the pin-shaped component; A step in which multiple segmented images are obtained by dividing each of the captured images so that multiple regions of interest appear on different images from each other; and, A vision inspection method for a pin-shaped component according to claim 6, comprising the step of acquiring a plurality of modified images in which the part of interest appearing in each of the divided images is changed to the predetermined orientation.

10. In the step where the merged image is obtained, The vision inspection method for a pin-shaped component according to claim 6, wherein the combined image is obtained by continuously connecting a plurality of extraction target regions to each other so that they match the actual positions on the pin-shaped component.

11. In the step in which the modified image is obtained, The method for visual inspection of a pin-shaped component according to claim 9, wherein the predetermined posture is the posture captured when the pin-shaped component is precisely perpendicular to the inspection stage.

Images