Device and method for determining the presence or absence of holes

Abstract

The present invention provides a hole presence / absence determination device and method that can accurately determine the presence or absence of holes in the first workpiece panel with a simple configuration, while improving transport efficiency and being unaffected by the influence of subsequent workpiece panels being transported and external ambient light. [Solution] The system includes an infrared light source 2 that irradiates the surface of the first workpiece panel P with infrared light from a direction inclined with respect to the transport direction CC, a monochrome camera 3 that captures infrared light in a predetermined region including the hole 10 from the downstream side of the transport direction CC, and a hole presence / absence determination unit 7 that determines the presence or absence of the hole 10 based on the image of the predetermined region captured by the monochrome camera 3.

Description

Technical Field

[0001] The present invention relates to a hole presence / absence discrimination device and a hole presence / absence discrimination method that are not affected by the influence of subsequent workpieces to be processed being conveyed and the influence of external ambient light, can increase the conveyance efficiency, and can accurately discriminate the presence or absence of holes in the first workpiece to be processed with a simple configuration.

Background Art

[0002] Conventionally, in the production process of vehicles and the like, there are cases where workpieces to be processed that have the same shape but different hole positions depending on optional specifications are stacked and conveyed at a fixed pitch. Since the positions of the holes in the conveyed workpieces to be processed may be different, when taking out the conveyed workpieces to be processed for the next processing, it is determined whether or not holes corresponding to the next processing are formed at predetermined positions on the workpieces to be processed.

[0003] In Patent Document 1, in an uneven shape recognition device, a plurality of light sources arranged with their positions shifted from each other are sequentially lit individually to image a recognition target, and the shape of the recognition target is recognized from an image of the shadow region of the recognition target generated by illumination from each light source.

[0004] In addition, Patent Document 2 describes a conveying device that conveys buttons, and includes an illumination device that irradiates illumination light obliquely forward with respect to one surface of the button, images the shadow of the button formed by the irradiation light, and discriminates the front and back of the button by recognizing the uneven shape of the button from the image of the shadow.

[0005] Furthermore, Patent Document 3 describes a Braille inspection device that evaluates the quality of Braille, and obtains height information of dots based on the length of an image of dots obtained by photography by irradiating oblique illumination light including line light obliquely.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] By the way, when the system is used to determine the presence or absence of through-holes rather than identifying irregularities on workpiece panels that are sequentially transported by the transport device, and if, according to the optional specifications, subsequent workpiece panels do not have holes, the image of the hole to be identified will have a smaller brightness difference between the hole and its surroundings due to the presence of the subsequent workpiece panel, making misidentification likely. If the pitch between workpiece panels is increased to increase this brightness difference between the hole and its surroundings, the transport efficiency of the workpiece panels will decrease.

[0008] Furthermore, the ambient light at the location where the presence or absence of holes in the workpiece is determined can cause color unevenness in the image of the holes. This color unevenness also reduces the brightness difference between the holes and the surrounding areas, making misidentification more likely.

[0009] The present invention has been made in view of the above, and aims to provide a hole presence / absence determination device and hole presence / absence determination method that can accurately determine the presence or absence of holes in the first workpiece panel with a simple configuration, while improving transport efficiency, and without being affected by the influence of subsequent workpiece panels being transported or external ambient light. [Means for solving the problem]

[0010] To solve the above-mentioned problems and achieve the objective, the hole presence / absence determination device according to the present invention is a hole presence / absence determination device that determines the presence or absence of a hole at a predetermined position on the first workpiece when sequentially removing the first workpiece from a conveying device that conveys a plurality of workpiece panels, each of which is permitted to have a hole drilled at the same predetermined position at one or more predetermined positions on the panel, by stacking them sequentially at a predetermined pitch in a conveying direction perpendicular to the surface of the workpiece panels, and is characterized by comprising: an infrared light source that irradiates the surface of the first workpiece panel with infrared light from a direction inclined with respect to the conveying direction; a monochrome camera that captures infrared light in a predetermined region including the hole at the predetermined position from the downstream side in the conveying direction; and a hole presence / absence determination unit that determines the presence or absence of a hole at the predetermined position based on the image of the predetermined region captured by the monochrome camera.

[0011] Furthermore, the hole presence / absence determination device according to the present invention is characterized in that, in the above invention, the hole presence / absence determination unit determines that there is a hole at the predetermined location when the proportion of the non-reflective area that is the shadow of the outer surface of the hole to the predetermined area is equal to or greater than a predetermined value.

[0012] Furthermore, the hole presence / absence determination device according to the present invention is characterized in that, in the above invention, the hole presence / absence determination unit binarizes the image of the predetermined region to separate the non-reflective region from the reflective region, and determines that there is a hole at the predetermined location if the proportion of the non-reflective region to the predetermined region is equal to or greater than a predetermined value.

[0013] Furthermore, the hole presence / absence determination device according to the present invention is characterized in that, in the above invention, the hole presence / absence determination unit determines that there is a hole at the predetermined location when the agreement ratio between the master image obtained by binarizing the predetermined region when there is a hole and the image obtained by binarizing the predetermined region captured by the monochrome camera is equal to or greater than a predetermined rate.

[0014] Furthermore, the hole presence / absence determination device according to the present invention is characterized in that the monochrome camera captures infrared light through a visible light cut filter.

[0015] Furthermore, the hole presence / absence determination device according to the present invention is characterized in that, in the above invention, the monochrome camera is arranged on a camera position movement unit which is driven and controlled by a camera position control unit, the camera position control unit acquires position data of a hole drilled in the earliest workpiece panel, and performs drive control to direct the optical axis of the monochrome camera parallel to the transport direction and towards the center position of the hole indicated by the position data.

[0016] Furthermore, the hole presence / absence determination device according to the present invention is characterized in that, in the above invention, the hole presence / absence determination unit is provided with a plurality of stepwise predetermined values, each having a threshold value that is progressively larger than the predetermined value, and as the proportion occupied by the non-reflective area exceeds each stepwise predetermined value, it determines that there are holes continuously at the same position in the upstream workpiece panel following the earliest workpiece panel.

[0017] Furthermore, the present invention relates to a hole presence / absence determination method, which determines the presence or absence of a hole at a predetermined position on the first workpiece when sequentially removing the first workpiece from a conveying device that conveys a plurality of workpieces, each of which is permitted to have a hole drilled at the same predetermined position at one or more predetermined positions on the panel, by sequentially stacking them at a predetermined pitch in a conveying direction perpendicular to the surface of the workpieces, and is characterized by irradiating the surface of the first workpiece from a direction inclined with respect to the conveying direction with infrared light, imaging the infrared light in a predetermined region including the hole at the predetermined position from the downstream side in the conveying direction, and determining the presence or absence of a hole at the predetermined position based on the image of the predetermined region captured. [Effects of the Invention]

[0018] According to the present invention, the presence or absence of holes in the first workpiece can be accurately determined with a simple configuration, while increasing transport efficiency, and without being affected by the influence of subsequent workpieces being transported or external ambient light. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a schematic diagram showing the configuration of a system including a hole presence / absence detection device, which is an embodiment of the system. [Figure 2] FIG. 2 is a schematic diagram showing the arrangement state of the infrared light source and the monochrome camera with respect to the hole in the hole presence / absence discrimination device. [Figure 3] FIG. 3 is a diagram showing an example of an image of a predetermined area. [Figure 4] FIG. 4 is a flowchart showing the hole presence / absence discrimination processing procedure by the hole presence / absence discrimination device. [Figure 5] FIG. 5 is an explanatory diagram for explaining the hole presence / absence discrimination processing using the master image. [Figure 6] FIG. 6 is an explanatory diagram for explaining an example of the discrimination processing as to whether holes are continuously formed at the same position of the work panel to be processed which is continuously arranged with a plurality of stepwise predetermined values having threshold values sequentially larger than a predetermined value.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0021] <System Configuration> FIG. 1 is a schematic diagram showing the configuration of a system 100 including a hole presence / absence discrimination device 1 according to the present embodiment. FIG. 2 is a schematic diagram showing the arrangement state of the infrared light source 2 and the monochrome camera 3 with respect to the hole 10 in the hole presence / absence discrimination device 1.

[0022] As shown in FIG. 1, in the production process of a vehicle or the like, the system 100 sequentially conveys a work panel P in which a cylindrical hole 10 is drilled in a press working system 101 to the side of a welding system device 103 by a conveying device 102, and welds the conveyed work panel P in the welding system device 103.

[0023] The conveying device 102 sequentially loads the workpiece panels P, which have been perforated by the press working system 101, at a predetermined pitch PT (see Figure 2) and conveys them to the stopping position PS. The workpiece panels P on the conveying device 102 are conveyed overlapping at a pitch PT in the conveying direction CC perpendicular to the surface of the workpiece panel. At the stopping position PS, the workpiece panels P whose presence or absence of holes has been determined are taken out to the welding system device 103, where plug welding is performed at the location of the holes 10.

[0024] The hole presence / absence determination device 1 determines whether or not a machined hole 10 has been made at the stopping position PS of the workpiece panel P. Details will be described later.

[0025] The system control device 105 is connected to the press working system 101, the conveying device 102, the welding system 103, and the hole presence / absence determination device 1 to perform overall control. As described above, the position of the holes 10 in each workpiece panel P may or may not be the same as the position of the holes 10 in subsequent workpiece panels, depending on the optional specifications. The positions of these holes 10 are known after the holes have been drilled by the press working system 101, and this position data is notified to the hole presence / absence determination device 1 via the system control device 105.

[0026] <Device configuration> The hole presence / absence determination device 1 comprises an infrared light source 2, a monochrome camera 3, and a control unit 5. The control unit 5 also comprises a camera position control unit 6 and a hole presence / absence determination unit 7. The infrared light source 2 irradiates the surface of the foremost workpiece panel with infrared light from a direction inclined at an angle θ with respect to the transport direction CC.

[0027] As shown in Figures 1 and 2, the monochrome camera 3 captures infrared light in a predetermined region E including the hole 10 from the downstream side of the transport direction CC. The optical axis C of the monochrome camera 3 is oriented so as to pass through the center HC of the hole 10 and be parallel to the transport direction CC. The monochrome camera removes external visible light through the visible light cut filter 3a and receives infrared light to capture the predetermined region E.

[0028] The monochrome camera 3 is positioned at the upper tip of the camera position movement unit 4, such as a robot arm. The camera position control unit 6 acquires position data of the drilled hole 10 relative to the foremost workpiece panel P1 stopped at the stop position PS from the system control unit 105, and drives and controls the camera position movement unit 4 so that the optical axis C of the monochrome camera 3 is parallel to the transport direction CC and passes through the center HC of the hole 10. In this state, the monochrome camera 3 captures an image of a predetermined region E including the hole 10 and sends the captured image to the control unit 5.

[0029] When infrared light is obliquely shone from an infrared light source 2 onto a predetermined region E containing the hole 10, the hole 10, as viewed from the optical axis C, forms a non-reflective region E1 where infrared light is not reflected due to the shadow of the outer surface of the hole 10, and a reflective region E2 where infrared light is reflected. In addition, infrared light is reflected from the surface of the workpiece panel P where the hole 10 is not formed.

[0030] As a result, as shown in Figure 3, the image D of the hole 10 in a predetermined rectangular region E centered on the center HC is captured as a non-reflective region E1 and a reflective region E2, resembling a waxing moon. The hole presence / absence determination unit 7 determines the presence or absence of the hole 10 in the predetermined region E based on the image D of the predetermined region E captured by the monochrome camera 3. For example, the hole presence / absence determination unit 7 determines that there is a hole 10 if the ratio of the non-reflective region E1 to the predetermined region E is greater than or equal to a predetermined value Bth, for example, if the predetermined value Bth is 1 / 5 or more, and determines that there is no hole 10 if it is less than the predetermined value Bth. The reason why the ratio of the non-reflective region E1 to the predetermined region E is set to be greater than or equal to a predetermined value Bth in the hole presence / absence determination process is that there is a possibility that a hole 10 at the same position as the one in the subsequent workpiece panel P2 may be formed in the workpiece panel P1, and in this case, the ratio of the non-reflective region E1 to the predetermined region E will be large. Note that if no hole 10 is formed, the ratio of the non-reflective region E1 to the predetermined region E will be approximately 0.

[0031] Furthermore, the reason for using a rectangular predetermined region E instead of the circular region of the hole 10 is to reduce the image processing load. In addition, various image processing methods are possible for the hole presence / absence determination unit 7, but for example, the multi-tone image of the predetermined region E is binarized to separate the non-reflective region E1 and the reflective region E2, and the presence of the hole 10 is determined when the ratio (number of pixels) of the non-reflective region E1 to the predetermined region E is equal to or greater than a predetermined value Bth.

[0032] Furthermore, while the angle θ is, for example, around 45°, it is advisable to increase or decrease the non-reflective region E1 depending on the thickness of the workpiece panel P. For example, when the thickness of the workpiece panel P is thin, it is advisable to increase the angle θ to increase the non-reflective region E1.

[0033] <Perforation / Absence Determination Process> Figure 4 is a flowchart showing the hole presence / absence determination procedure by the hole presence / absence determination device 1. As shown in Figure 4, first, the control unit 5 instructs the infrared light source 2 to irradiate infrared light, directing the infrared light toward the surface of the first workpiece panel P1 (step S101). Then, the control unit 5 determines whether or not the first workpiece panel P1 has been transported to the stop position PS (step S102). Whether or not the first workpiece panel P1 has been transported to the stop position PS is determined by notification from the system control device 105.

[0034] If the first workpiece panel P1 is not transported to the stop position PS (step S102: No), this determination process is repeated. If the first workpiece panel P1 is transported to the stop position PS (step S102: Yes), the position data of the holes 10 is acquired via the system control device 105 (step S103). This position data of the holes 10 is the position data of all the holes 10 of the first workpiece panel P1.

[0035] Subsequently, the camera position control unit 6 moves the monochrome camera 3 to capture an image of a predetermined region E including the hole 10 that is initially identified, based on the position data of the hole 10 (step S104). Then, the control unit 5 causes the monochrome camera 3 to perform an imaging process to acquire an image of the predetermined region E (step S105).

[0036] Subsequently, the hole presence / absence determination unit 7 determines, based on the image of the captured predetermined region E, whether the ratio of the non-reflective region E1 to the predetermined region E is greater than or equal to a predetermined value Bth (step S106). If the ratio of the non-reflective region E1 to the predetermined region E is greater than or equal to the predetermined value Bth (step S106: Yes), it is determined that there is a hole 10 in the predetermined region E (step S107). On the other hand, if the ratio of the non-reflective region E1 to the predetermined region E is not greater than or equal to the predetermined value Bth (step S106: No), it is determined that there is no hole 10 in the predetermined region E (step S108).

[0037] Subsequently, the control unit 5 determines whether the determination of whether or not there are holes in all the holes 10 in the workpiece panel P1 has been completed (step S109). If the determination of whether or not there are holes in all the holes 10 in the workpiece panel P1 has not been completed (step S109: No), the process proceeds to step S104 to perform the hole determination process for the next hole 10. On the other hand, if the determination of whether or not there are holes in all the holes 10 in the workpiece panel P1 has been completed (step S109: Yes), the hole determination result is notified to the system control device 105 (step S110). If the system control device 105 determines that there are no holes 10, it performs the error handling procedure that has been set in advance.

[0038] Subsequently, the control unit 5 determines whether the hole presence / absence determination process for all the workpiece panels P being transported has been completed (step S111). If the hole presence / absence determination process for all workpiece panels P has not been completed (step S111: No), the process proceeds to step S102 to continue the hole presence / absence determination process for the next workpiece panel P. If the hole presence / absence determination process for all workpiece panels P has been completed (step S111: Yes), the process ends.

[0039] In this embodiment, the presence or absence of holes 10 can be determined regardless of the width of the pitch PT, so the pitch spacing can be narrowed, and the transport efficiency and space efficiency of the transport device 102 can be improved. Furthermore, the monochrome camera 3 receives infrared light emitted from the infrared light source 2 via a visible light cut filter and acquires an image of a predetermined region E, so it is not affected by external ambient light such as external visible light and can perform highly accurate hole presence or absence determination. Moreover, since only one infrared light source 2 is required as the light source, a simple configuration can be achieved.

[0040] <Variation> In the above embodiment, the multi-tone image of a predetermined region E was binarized to separate the non-reflective region E1 and the reflective region E2, and it was determined that there was a hole 10 if the proportion (number of pixels) of the non-reflective region E1 to the predetermined region E was equal to or greater than a predetermined value Bth. However, as shown in Figure 5, it is also possible to determine that there is a hole 10 if the agreement rate between the master image MD obtained by binarizing the predetermined region E when there is a hole 10 and the image D obtained by binarizing the predetermined region E captured by the monochrome camera 3 is equal to or greater than a predetermined rate. This agreement rate is determined based on the number of pixels in the non-reflective region E1 that match the non-reflective region E0 relative to the number of pixels in the non-reflective region E0.

[0041] Furthermore, in the above embodiment, the monochrome camera 3 was moved to capture images of a predetermined area E of each hole 10. However, if an image that satisfies the resolution requirements can be obtained, the entire image of the workpiece panel P1 may be captured at once, and the hole presence / absence determination process for each predetermined area E may be performed from this captured image.

[0042] Furthermore, although the above embodiment assumed that the hole 10 was cylindrical in shape, it is not limited to this and may be a prismatic hole. Note that the hole 10 can also be a recessed hole.

[0043] Furthermore, in the above embodiment, each workpiece panel P was arranged at a predetermined pitch PT interval, but this pitch PT may be 0.

[0044] Furthermore, in the above embodiments and modifications, image processing such as binarization or a master image was used for hole presence / absence determination. However, after performing edge processing, pattern matching of the shape of the edge portion of the hole 10 may be performed for determination. Alternatively, the determination may be made using histograms of the vertical and horizontal pixels of a predetermined region E.

[0045] As shown in Figure 6, the hole presence / absence determination unit 7 may be provided with a plurality of stepwise predetermined values ​​B2th, B3th, each having a threshold progressively larger than the predetermined value Bth, and as the proportion occupied by the non-reflective region E1 exceeds each stepwise predetermined value B2th, B3th, it may be determined that there are holes 10 consecutively at the same position in the upstream workpiece panels P2 and P3 that follow the earliest workpiece panel P1.

[0046] Figure 6(a) shows that a hole 10 is formed only in the first workpiece panel P1, and no holes 10 are formed in the same positions on the subsequent workpiece panels P2 and P3. In this case, as in the above embodiment, if, for example, the predetermined value Bth is 2 / 10, the proportion B occupied by the non-reflective region E1 becomes 3 / 10.

[0047] Furthermore, Figure 6(b) shows that holes 10 are formed at the same position on the first workpiece panel P1 and the subsequent workpiece panel P2, but no holes 10 are formed at the same position on the subsequent workpiece panel P3. In this case, for example, the proportion B occupied by the non-reflective area E1 becomes large at 6 / 10, but since the stepwise predetermined value B2th = 5 / 10 or more, it is determined that there are consecutive holes 10 at the same position on the first workpiece panel P1 and the subsequent workpiece panel P2.

[0048] Furthermore, Figure 6(c) shows that holes 10 are continuously formed at the same position on the first workpiece panel P1 and the subsequent workpiece panels P2 and P3, but no holes 10 are formed at the same position on the subsequent workpiece panel P4. In this case, for example, the proportion B occupied by the non-reflective area E1 becomes even larger at 9 / 10, but since the stepwise predetermined value B3th = 8 / 10 or more, it is determined that there are continuous holes 10 at the same position on the first workpiece panel P1 and the subsequent workpiece panels P2 and P3.

[0049] In this way, by providing stepwise predetermined values ​​B2th, B3th, etc., in addition to the predetermined value Bth, it is possible to determine whether or not there are consecutive holes 10 at the same position on the subsequent workpiece panel, thereby improving the efficiency of the hole presence / absence determination process.

[0050] It should be noted that the configurations illustrated in the above embodiments and each of the modified examples are functionally schematic and do not necessarily have to be physically arranged as shown. In other words, the distributed and integrated forms of each device are not limited to those shown, and all or part of them can be functionally or physically distributed and integrated in any unit according to various loads and usage conditions. [Industrial applicability]

[0051] The hole presence / absence detection device and hole presence / absence detection method according to the present invention are useful when it is desirable to accurately determine the presence or absence of holes in the first workpiece panel with a simple configuration, while improving transport efficiency, and without being affected by the influence of subsequent workpiece panels being transported or external ambient light. [Explanation of symbols]

[0052] 1 Hole presence / absence determination device 2. Infrared light source 3. Monochrome Camera 3a Visible light cut filter 4. Camera position movement unit 5. Control Unit 6. Camera position control unit 7 Hole presence / absence determination section 10 holes 100 Systems 101 Pressing System 102 Conveying device 103 Welding System Equipment 105 System Control Unit B Percentage Bth predetermined value B2th, B3th Stepwise predetermined values C optical axis CC Conveying Direction Image D The area defined by E E0, E1 Non-reflective domain E2 Reflection Area HC Center MD Masuzu's portrait P,P1~P4 are processed パネル PS Stop position PT ピッチ θ angle

Claims

1. A hole presence / absence determination device for determining whether there is a hole at a predetermined position on the first workpiece when sequentially removing the first workpiece from a conveying device that conveys multiple workpieces, each of which is permitted to have a hole drilled at one or more predetermined positions on the panel, stacked sequentially at a predetermined pitch in a conveying direction perpendicular to the surface of the workpieces, wherein the first workpiece is permitted to have a hole drilled at the same predetermined position on the first workpiece, An infrared light source that irradiates the surface of the first workpiece panel with infrared light from a direction inclined with respect to the transport direction, A monochrome camera that captures infrared light in a predetermined region including the hole at the predetermined position from the downstream side in the transport direction, A hole presence / absence determination unit that determines the presence or absence of a hole at a predetermined position based on the image of the predetermined area captured by the monochrome camera. A hole presence / absence determination device characterized by comprising the following:

2. The hole presence / absence determination device according to claim 1, characterized in that the hole presence / absence determination unit determines that there is a hole at the predetermined location when the proportion of the non-reflective area that is in the shadow of the outer surface of the hole to the predetermined area is equal to or greater than a predetermined value.

3. The hole presence / absence determination device according to claim 2, characterized in that the hole presence / absence determination unit binarizes the image of the predetermined region to separate the non-reflective region from the reflective region, and determines that there is a hole at the predetermined location if the proportion of the non-reflective region to the predetermined region is equal to or greater than a predetermined value.

4. The hole presence / absence determination device according to claim 1, characterized in that the hole presence / absence determination unit determines that there is a hole at the predetermined location when the agreement ratio between the master image obtained by binarizing the predetermined region when there is a hole and the image obtained by binarizing the predetermined region captured by the monochrome camera is equal to or greater than a predetermined rate.

5. The hole presence / absence determination device according to claim 1, characterized in that the monochrome camera captures infrared light through a visible light cut filter.

6. The monochrome camera is positioned on a camera position movement unit that is driven and controlled by a camera position control unit. The hole presence / absence determination device according to claim 1, characterized in that the camera position control unit acquires position data of a hole drilled in the earliest workpiece panel, and performs drive control to direct the optical axis of the monochrome camera parallel to the transport direction towards the center position of the hole indicated by the position data.

7. The hole presence / absence determination device according to claim 2 or 3, characterized in that the hole presence / absence determination unit is provided with a plurality of stepwise predetermined values ​​having thresholds that are progressively larger than the predetermined value, and as the proportion occupied by the non-reflective area exceeds each stepwise predetermined value, it is determined that there are holes continuously at the same position in the upstream workpiece panel following the earliest workpiece panel.

8. A method for determining whether or not there is a hole at a predetermined position on a panel when sequentially removing the first panel being transported from a transport device that transports multiple workpiece panels, each of which is permitted to have a hole drilled at one or more predetermined positions on the panel, stacked sequentially at a predetermined pitch in a transport direction perpendicular to the surface of the workpiece panels, the method for determining whether or not there is a hole at the predetermined position on the first workpiece panel, A method for determining the presence or absence of a hole, characterized by irradiating the surface of the earliest workpiece panel with infrared light from a direction inclined with respect to the transport direction, capturing an image of the infrared light in a predetermined region including the hole at the predetermined position from the downstream side in the transport direction, and determining the presence or absence of a hole at the predetermined position based on the captured image of the predetermined region.

Images