JP2000234918A - Method and device for inspecting laser welding defect - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an required molten part such as a hole or dent generated on the laser-welding-side surface of an object to be inspected as well as a through hole generated at the object, and to automatically judge degradation in welding strength due to molten part, for precision inspection of the defect of an object to be inspected. SOLUTION: A welding position detecting part 6 which detects the central part of a welding part using the image data of an object 50 to be inspected which is imaged with an image input device, a labeling process part 7 for labeling a central part and its surrounding part detected with the welding position detecting part 6, and a welding part defect judging part 8 wherein a specified feature amount is calculated for each labeled region by the labeling process part 7 and then, based on the calculated feature amount, the object to be inspected is judged for soundness, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser welding defect inspection apparatus and method for inspecting the presence or absence of a defect in a laser welded portion by performing image processing on the welded portion.

[0002]

2. Description of the Related Art As is well known, laser welding is performed by melting and welding a welding material or an object to be welded using laser light such as a gas laser or a solid laser. Such laser welding is capable of performing precise welding by utilizing the good directivity of laser light, and is different from electron beam welding that requires a vacuum environment in an open (natural) environment. Since it can be performed, precise welding can be easily performed by small-scale equipment. 2. Description of the Related Art In recent years, a laser welding defect inspection apparatus that inspects an object to be welded subjected to laser welding as an inspection object is known. In such a laser welding defect inspection apparatus, it has become common to perform image processing on an image (object to be inspected) photographed by an imaging unit including a television camera and automatically perform the defect inspection. I have.

Here, a conventional laser welding defect inspection apparatus will be specifically described with reference to FIG. FIG.
It is a block diagram showing the composition of the conventional laser welding defect inspection device. As shown in FIG. 8, in the conventional laser welding defect inspection apparatus, an illuminator 52 is arranged below a positioning table 51 on which an inspection object 50 is placed, and a television camera 53 is arranged above the inspection object 50. Has been established. The inspection object 50 is, for example, an aluminum foil having a thickness of about 0.1 mm superimposed on the upper and lower tiers, and the surface of one of the aluminum foils is irradiated with a laser beam and the aluminum foils are welded to each other.
The positioning table 51 is formed using a transparent glass or a transparent synthetic resin, and is operated by a driving mechanism (not shown) that operates according to an instruction signal from the main controller 59.

The television camera 53 is connected to the laser welding defect inspection processing section 54 and outputs image data of the image of the inspection object 50 taken. Laser welding defect inspection processing unit 54
Includes an image storage unit 55, a labeling processing unit 56, an area calculation processing unit 57, and a defect determination unit 58. The image storage unit 55 stores the image data of the inspection target 50 from the television camera 53. The labeling processing unit 56 performs a labeling process on the image data stored in the image storage unit 55. More specifically, the labeling processing unit 56
The luminance of the image data of 0 is divided into light and shade based on a predetermined binarization threshold value, and a region which is a block portion of a lighter image is detected and numbered (labeled) sequentially. The area calculation processing unit 57 calculates the area for each of the regions labeled by the labeling processing unit 56. Defect judgment unit 58
Determines for each labeled region whether or not the region is a defect based on the area calculated by the area calculation processing unit 57. The defect judging unit 58 judges a non-defective product or a defective product according to the presence or absence of a defective portion,
The result of the determination is output to the main controller 59. The main controller 59 controls the entire defect inspection apparatus, inputs a determination result from the defect determination unit 58, and notifies an operator.

In the above-described conventional laser welding defect inspection apparatus, an inspection object 50 is disposed on a positioning table 51 formed of a transparent material, and a television camera 53 and an illuminator 5 are positioned above and below the positioning table 51, respectively.
2 was arranged. Accordingly, in the conventional laser welding defect inspection apparatus, when a through hole vertically penetrating the positioning table 51 is formed in the inspection object 50, the laser welding defect inspection processing unit 54 sets the through hole to a light image area. As a defective part of the inspection object 50, and the inspection object 50 is determined to be defective.

Hereinafter, the operation of the conventional laser welding defect inspection apparatus will be described with reference to FIGS. FIG.
9 is a flowchart showing the operation of the laser welding defect inspection device shown in FIG. 9, in the conventional laser welding defect inspection apparatus, an inspection object 50 on a transparent positioning table 51 is imaged by a television camera 53 in a state where light is irradiated from below by an illuminator 52, and the image data is imaged. It is stored in the storage unit 55. Then, the labeling processing unit 56 performs a labeling process on the image data stored in the image storage unit 55 using a predetermined binarization threshold, and sequentially numbers the light image areas of the inspection object 50 (step S51). ). Next, the area calculation processing unit 57
The area of each labeled region is calculated and output to the defect determination unit 58 (step S52). continue,
The defect determining unit 58 determines whether there is a defective portion in the inspection target 50 based on the calculated area (Step S53). If it is determined that there is no defective portion in the inspection target 50, the defect determination unit 50 determines that the inspection target 50 is non-defective (step S54), and outputs a result of the non-defective determination to the main controller 59. And end the inspection. On the other hand, when it is determined that the inspection target 50 has a defective portion, the defect determination unit 50 determines that the inspection target 50 is defective (step S55), and determines the determination result of the defective determination as the main result. This is output to the controller 59 and the inspection is completed.

[0007]

With the conventional laser welding defect inspection apparatus as described above, it has been difficult to detect defects other than the above-described through holes. For this reason, the conventional laser welding defect inspection apparatus has a problem that the defect inspection of the inspection object cannot be performed accurately. Specifically, in this conventional laser welding defect inspection apparatus, detection of unnecessary melted portions such as holes and depressions on the surface of the inspection target 50 to which laser welding has been performed, and detection of welding strength by the melted portions. No decrease could be determined. As a result, in the conventional laser welding defect inspection apparatus, the accuracy of the defect inspection is low, and it is necessary to re-perform an inspection by an operator, for example, in order to determine the presence or absence of the above-described unnecessary melting portion and a decrease in welding strength. was there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and not only a through hole formed in an inspection object but also a hole gap formed in a surface of the inspection object on a laser welding side. Laser welding defect inspection equipment that can detect unnecessary melting parts such as pits and depressions, and can automatically determine the decrease in welding strength due to the melting parts, and can perform defect inspection of inspection objects with high accuracy. And a defect inspection method.

[0009]

SUMMARY OF THE INVENTION A laser welding defect inspection apparatus according to the present invention is provided with an image input apparatus for capturing an image of an inspection object from above and generating image data of a grayscale image thereof, and disposed above the inspection object. The illuminator for illuminating the inspection target, using image data from the image input device, a welding position detecting unit that detects a central portion of the welding portion, a central portion detected by the welding position detecting unit, and the like. A labeling processing unit that performs a labeling process on the peripheral portion, and a predetermined feature amount is calculated for each of the regions labeled by the labeling processing unit, and based on the calculated feature amount, a non-defective product or an unsatisfactory inspection object. It is equipped with a welded part defect judging unit for judging non-defective products. With this configuration, it is possible to detect not only a through hole generated in the inspection target, but also an unnecessary melting portion such as a hole or a dent generated on the surface on the laser welding side of the inspection target. A decrease in welding strength due to the melting portion can be automatically determined, and a defect inspection of the inspection object can be performed with high accuracy.

A defect inspection method according to the present invention includes a generating step of capturing an image of an inspection object from above and generating image data of a gray-scale image of the inspection object. A detecting step of detecting
A labeling step of performing a labeling process on the central portion and its peripheral portion detected in the detection step, and for each region labeled in the labeling step,
A predetermined feature amount is calculated, and based on the calculated feature amount,
A determination step is provided for determining a non-defective or defective product to be inspected. With this configuration, it is possible to detect not only a through hole generated in the inspection target, but also an unnecessary melting portion such as a hole or a dent generated on the surface on the laser welding side of the inspection target. A decrease in welding strength due to the melting portion can be automatically determined, and a defect inspection of the inspection object can be performed with high accuracy.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment showing a laser welding defect inspection apparatus and a defect inspection method according to the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a block diagram showing a configuration of a laser welding defect inspection apparatus according to a first embodiment of the present invention. FIG. 2 is an explanatory diagram showing the positional relationship among the inspection object, the illuminator, and the television camera shown in FIG. As shown in FIG. 1, the laser welding defect inspection apparatus according to the present embodiment is provided with a positioning table 1 on which an inspection object 50 is placed, and is provided above the positioning table 1.
A ring-shaped illuminator 2 for illuminating the inspection object 50, and a television camera installed above the illuminator 2 for imaging the inspection object 50 on the positioning table 1 and generating image data of a grayscale image thereof 3 is provided. Further, the laser welding defect inspection apparatus of this embodiment includes a television camera 3
Laser welding defect inspection processing unit 4 for inputting image data of inspection object 50 imaged by the above and performing defect inspection of inspection object 50 based on the image data, and main controller 9 for controlling the entire defect inspection apparatus Is provided. The positioning table 1 is provided with a drive mechanism (not shown) that operates based on an instruction signal from the main controller 9. As a result, the positioning table 1
It is moved to a desired position. In the laser welding defect inspection apparatus according to the present embodiment, the inspection object 50 is previously positioned at a predetermined position by the positioning table 1 such that the center portion (hereinafter, also referred to as “nugget”) N of the welded portion is located almost directly below the television camera 3. And a defect inspection is performed.

The illuminator 2 is supported by a support member (not shown) and is disposed between the positioning table 1 and the television camera 3. This illuminator 2 preferably has a diameter of 3
It has a ring-shaped halogen lamp of about 0 mm, and illuminates the inspection object 50 on the positioning table 1 from an oblique direction. Specifically, as shown in FIG. 2, the illuminator 2 reflects light reflected from the nugget N of the inspection object 50 (arrow in FIG. 2).
A ”) enters the television camera 3, and the inspection object 50 so that the reflected light (illustrated by the arrow“ B ”in the figure) of the peripheral portion of the nugget N does not directly enter the television camera 3.
At a predetermined angle θ (for example, about 30 °). Thereby, when an unnecessary dissolved portion (defect portion) including a through hole, a hole, a dent, or the like is not generated in the inspection object 50, the light from the illuminator 2 emits light from the nugget N whose surface is uneven. The light is diffusely reflected only at the portion, shines whiter than the surrounding portion, and is captured and detected as a pale image. In addition, since the above-described defective portion is formed with an uneven surface, if the defective portion occurs in the inspection object 50, it is detected as a pale image shining white like the nugget N (for details, see FIG. See below).

As shown in FIG. 2, the inspection object 50 is made of aluminum foil 50a, 50 having a thickness of about 0.1 mm, for example.
b is laid on the upper and lower tiers, and a laser beam is irradiated from the surface side of one of the aluminum foils 50a and the aluminum foils 50a, 50
b are welded to each other. These aluminum foils 50
The welded product consisting of a and 50b is used, for example, as a safety valve in a sealing plate of a lithium ion battery.

Returning to FIG. 1, the television camera 3 as an image input device converts the imaged inspection object 50 into image data of a grayscale image having a predetermined gradation, and sends it to the laser welding defect inspection processing section 4. Output. In detail, TV camera 3
Preferably, the inspection object 50 is imaged with 512 × 480 pixels vertically, horizontally, and converted into image data having, for example, 256 gradations at each pixel and output. The laser welding defect inspection processing unit 4 includes an image storage unit 5, a welding position detection unit 6 for detecting the position of the nugget N of the inspection target 50 using the image data stored in the image storage unit 5, The apparatus includes a labeling processing unit 7 for performing a labeling process on the image data stored in the storage unit 5 and a weld defect determining unit 8 for determining a defect occurring in the inspection object 50. The image storage unit 5 includes a RAM or a similar data recording device, and stores image data from the television camera 3 in pixel units.

The welding position detector 6 uses the image data of the inspection object 50 to determine whether or not the nugget N can be identified and detected. Specifically, the welding position detection unit 6 checks whether or not an area of a pale image including pixels whose gradation value is equal to or less than a predetermined value exists in the center of the inspection object 50. If a light image region exists, the welding position detecting unit 6 detects the region as a nugget N, further calculates the position coordinates of the nugget N, and sends it to the labeling processing unit 7 and the weld defect determining unit 8. Output.
If the nugget N cannot be detected, the welding position detector 6
Informs the labeling processing unit 7 and the weld defect determination unit 8 that the nugget N could not be detected. Here, the position coordinates refer to the position of a pixel on a plane (two-dimensionally) in image data captured by the television camera 3. Since the nugget N is a portion constituting the central portion of the welded portion as described above, when the nugget N is detected, the welding position detecting unit 6 determines the position of each of a plurality of pixels constituting the outline on the plane of the nugget N. Output coordinates.

The labeling processing section 7 divides the gradation (luminance) of the image data of the inspection object 50 into one of light and shade based on a predetermined binarization threshold for each pixel, and forms a lighter image block. The regions are detected and numbering (labeling) is performed sequentially. The labeling processing unit 7 of the present embodiment performs the above-described labeling processing on the nugget N and its peripheral portion based on the position coordinates of the nugget N from the welding position detection unit 6. The labeling processing unit 7 outputs, for each of the labeled regions, the position coordinates of the pixels constituting the outline of the region to the weld defect determining unit 8. Weld defect determination unit 8
Determines whether the inspection object 50 has a defective portion based on the detection result of the nugget N from the welding position detection unit 6 and the labeled region from the labeling processing unit 7. Specifically, when the welding position detecting unit 6 notifies that the nugget N has not been detected, the welding unit defect determining unit 8 determines that the welding (melting) at the inspection object 50 is insufficient, and The inspection object 50 is determined to be defective. In addition, the welded part defect judging unit 8 calculates, for each of the labeled regions from the labeling processing unit 7, a feature amount including an area, a width, a length, and a directional intensity based on the position coordinates, and performs the inspection. It is determined whether unnecessary melted portions such as through holes, holes, dents, and the like are generated in the target object 50, and a decrease in welding strength due to the melted portions (details will be described later).

Here, a method for determining the nugget N and the defective portion in the laser welding defect inspection apparatus according to the present embodiment will be specifically described with reference to FIGS. FIG. 3 is an explanatory diagram showing an example of an image of the inspection object having no defect portion, which is captured by the television camera shown in FIG. FIG. 4 is an explanatory diagram showing an example of an image of an inspection object having a defective portion captured by the television camera shown in FIG. 1, and FIG. 5 is an enlarged view of the defective portion shown in FIG. is there. In the laser welding defect inspection apparatus of the present embodiment, first, the welding position detector 6 detects the nugget N,
The welded part defect determining unit 8 determines whether the detected nugget N is a defective part based on the feature amount. Further, the weld defect determining section 8 determines whether or not a defective portion has occurred around the nugget N. More specifically, the feature of the image of a non-defective welded product having no defective portion is that only the circular nugget N shown by the hatched portion in FIG. A light image area is not detected in the peripheral portion surrounded by broken lines C1 and C2 in FIG. As shown in FIG. 2, the peripheral portion is a portion formed in a mortar shape with the nugget N at the bottom, and the reflected light of the light from the illuminator 2 directly enters the television camera 3. Instead, the image is captured as a darker and darker image than the nugget N. Further, the nugget N may be imaged in a ring shape other than the circular shape shown in FIG.

On the other hand, as shown in FIGS. 4 and 5, an image of a defective welding part having a defective part is detected as a light image area in a peripheral part surrounded by broken lines C1 and C2. Is done. The defective portion F is an unnecessary dissolving portion including a hole and a pit formed on the surface of the inspection object 50 on the side of the television camera 3 (laser welding side). Labeled as In addition, welding at the inspection object 50 is insufficient,
That is, when the welding strength is insufficient, the nugget N is not formed, or even if the nugget N is formed, a ring-shaped area that shines white around the nugget N is detected and labeled. The weld defect determining unit 8 performs the following (1)
It is determined whether or not the labeled region is a nugget N or a defective portion based on the feature amount determination conditions shown in Expressions (4) to (4). (1) V1 ≤ area (S) ≤ V2, (2) V3 ≤ width (W) ≤ V4, (3) V5 ≤ length (L) ≤ V6, (4) V7 ≤ directional strength (H) ≤ V8 V1 to V8 in the equations (1) to (4) are predetermined threshold values set in the weld defect determining unit 8. The directional strength (H) is a parameter obtained by length (L) / width (W).

When the labeled area satisfies all of the above equations (1) to (4), the weld defect judging section 8 judges that area as a nugget N and satisfies one of the equations. If not, it is determined that the part is defective. Specifically, when the area of the labeled region is smaller than the threshold value V1, the weld defect determining unit 8 determines that the formed nugget N is small and determines that the welding strength is insufficient,
The inspection object 50 is determined to be defective. When the area is larger than the threshold value V2, the weld defect determining unit 8 determines that the formed nugget N is too large and determines that the welding strength is reduced, and regards the inspection object 50 as a defective product. to decide. Further, the weld defect determining unit 8 determines the extent of the area in two dimensions based on the width and the length, and determines whether an appropriate nugget N is formed. In addition, the weld defect determining unit 8 determines, based on the directional strength, a two-dimensional shape of the region, that is, a slender shape or a circular shape, and determines an appropriate nugget N.
It is determined whether or not is formed.

Further, when two or more nuggets N are detected, the weld defect determining unit 8 determines that unnecessary melting portions including through holes, holes, and depressions having the same shape as the nuggets N are generated. It is determined that the welding strength is reduced due to the melting portion of the test object, and the inspection object 50 is determined to be defective. Further, when one nugget N is detected and the other light image region, for example, the defective portion F is labeled, any one of the area, width, length, and directional intensity of the defective portion F is respectively The above-described threshold value V1,
When V3, V5, V7 or more, the weld defect determining section 8 determines that the welding strength is reduced by the defective portion F, and determines that the inspection object 50 is defective. It should be noted that all values of the area, width, length, and direction intensity of the labeled region other than the nugget N are equal to the threshold values V1, V
3, another predetermined value V smaller than V5 and V7, respectively.
When the values are less than 1 ', V3', V5 ', and V7', the weld defect determining unit 8 determines that the decrease in welding strength due to the region is acceptable, and determines that the inspection object 50 is defective. The configuration may be such that the product is determined to be non-defective without being performed.

Hereinafter, the operation of the laser welding defect inspection apparatus according to the present embodiment will be described with reference to FIGS. FIG. 6 is a flowchart showing the operation of the laser welding defect inspection device shown in FIG. As shown in FIG. 6, in the laser welding defect inspection apparatus according to the present embodiment, image data of a grayscale image of the inspection object 50 captured by the television camera 3 is stored in the image storage unit 5 (step S1). Thereafter, the welding position detector 6 checks whether the nugget N can be detected at the center of the inspection target 50 (step S2). If the nugget N can be detected, the welding position detection unit 6 calculates the position coordinates of the detected nugget N (Step S3) and outputs it to the labeling processing unit 7 and the weld defect determination unit 8. Next, based on the position coordinates of the nugget N from the welding position detection unit 6, the labeling processing unit 7 performs a labeling process on the nugget N and its surroundings (step S4), and welds the position coordinates of the labeled region. It is output to the part defect judging unit 8.

Subsequently, the welded part defect judging unit 8 calculates the above-mentioned feature amount from the position coordinates for each of the labeled regions from the labeling processing unit 7 (step S5), and based on the calculated feature amount. It is determined whether there is a defective portion (step S6). That is, the weld defect determining unit 8 determines whether the nugget N is formed in an appropriate shape and further checks whether a defective portion has occurred. Then, the nugget N is formed in an appropriate shape,
If there is no defective part, the weld defect determining unit 8 determines that the inspection object 50 is non-defective and notifies the main controller 9 (step S7). On the other hand, step S
In Step 2, if the nugget N cannot be detected, the welding position detecting unit 6 notifies the labeling processing unit 7 and the weld defect determining unit 8 that the nugget N has not been detected. Thereafter, the weld defect determining unit 8 determines the inspection object 5
0 is determined to be defective, and is notified to the main controller 9 (step S8). Further, when the nugget N is not formed in an appropriate shape in step S6,
Alternatively, also in the case where a defective portion occurs, the weld defect determining unit 8 determines that the inspection object 50 is defective and notifies the main controller 9.

As described above, in the laser welding defect inspection apparatus and the defect inspection method according to the present embodiment, the welding position detector 6
Detects the position of the center part (nugget) N of the welded part using the image data of the inspection object 50, and performs the labeling processing on the nugget N detected by the labeling processing unit 7 and the peripheral part. Further, for each of the labeled regions, the weld defect determining unit 8 calculates a predetermined characteristic amount from the position coordinates, and determines whether or not the nugget N is formed in an appropriate shape based on the calculated characteristic amount. And whether or not a defective portion has occurred.
Thereby, in the laser welding defect inspection apparatus and the defect inspection method of the present embodiment, not only the through hole generated in the inspection target, but also the hole gap or dent generated in the surface of the inspection target 50 on the laser welding side. Unwanted dissolved parts can be detected. Furthermore, the laser welding defect inspection device of the present embodiment,
Further, in the defect inspection method, it is possible to automatically determine a decrease in welding strength due to the above-mentioned melted portion, and it is possible to perform a defect inspection of the inspection object with high accuracy.

In addition to the above-mentioned television camera 3, a CCD
A configuration may be used in which a line sensor camera or area camera using (Charge Coupled Device) is used as an image input device for imaging the inspection target 50. Although the configuration using the image data of 256 gradations has been described, the laser welding defect inspection apparatus prototyped by the inventor was able to label and detect a defective portion with image data of about 20 to 30 gradations.

<< Second Embodiment >> FIG. 7 is a flowchart showing the operation of a laser welding defect inspection apparatus according to a second embodiment of the present invention. In this embodiment, in the configuration of the laser welding defect inspection apparatus, the center position of the nugget on the grayscale image of the inspection object is detected, and the presence or absence of a defect in the nugget and the peripheral portion is determined. The other parts are the same as those of the first embodiment, and the duplicated description thereof will be omitted. In the laser welding defect inspection apparatus of the present embodiment, first, the labeling processing unit 7
(FIG. 1) performs a labeling process on the image data of the inspection object 50 (FIG. 1) stored in the image storage unit 5 (FIG. 1). The weld defect determination unit 8 (FIG. 1) selects a nugget N from the labeled regions based on the feature amount calculated by calculating the above-described feature amount for each of the regions labeled by the labeling processing unit 7. ,Identify. The welding portion defect determining unit 8 outputs the specified position coordinates of the nugget N to the welding position detecting unit 6 (FIG. 1), and the welding position detecting unit 6 determines the position of the center (center of gravity) of the nugget N on the grayscale image. Calculate and detect coordinates. The welding position detection unit 6 outputs the coordinates of the detected center position to the labeling processing unit 7 and the welding defect determination unit 8. Labeling processing unit 7 and weld defect determination unit 8
Performs a labeling process and a process of determining the presence / absence of a defective portion on the nugget N and its peripheral portion, respectively, as in the first embodiment. As described above, the laser welding defect inspection apparatus according to the present embodiment detects the center position of the nugget N and determines whether or not the detected nugget N and the peripheral portion of the nugget N have a defective portion. Thereby, in the laser welding defect inspection apparatus of the present embodiment, since the center position of the nugget N in the image data on the plane is detected, the positioning table 1 can be moved based on the detected position, and the inspection can be performed. The inspection of the inspection object 50 can be performed without previously arranging the object 50 at a predetermined position by the positioning table 1.

Hereinafter, the operation of the laser welding defect inspection apparatus according to the present embodiment will be specifically described with reference to FIGS. In the following description, operations different from those of the first embodiment will be mainly described. FIG. 7 is a flowchart showing the operation of the laser welding defect inspection apparatus according to the second embodiment of the present invention. In FIG. 7, in the laser welding defect inspection apparatus of the present embodiment, as shown in Step S1,
The image data of the grayscale image of the inspection object 50 is stored in the image storage unit 5.
Is stored. Subsequently, the labeling processing unit 7 performs a labeling process on all the image data stored in the image storage unit 5, that is, the entire grayscale image (Step S).
9) The position coordinates of the labeled area are output to the weld defect determining section 8. Subsequently, for each of the labeled regions from the labeling processing unit 7, the weld defect determining unit 8 calculates the above-described feature amount from the position coordinates (step S1).
0). Next, for each of the regions labeled by the labeling processing unit 7, the weld part defect determination unit 8 calculates the above-described feature amount and specifies the nugget N from the labeled regions based on the calculated feature amount. Then, it is determined whether or not the nugget N can be detected (step S2 ′). Nugget N
Is determined, the welded portion defect determining unit 8 outputs the position coordinates of the specified nugget N to the welded position detecting unit 6. Then, the welding position detecting unit 6 calculates the coordinates of the center position of the nugget N on the grayscale image (Step S3 '), and outputs the coordinates to the labeling processing unit 7 and the weld defect determining unit 8. Thereafter, the laser welding defect inspection apparatus according to the present embodiment performs the same operation as that of the first embodiment to determine a non-defective product or a defective product.

As described above, in the laser welding defect inspection apparatus and the defect inspection method according to the present embodiment, the labeling processing unit 7 first checks the inspection object 50 stored in the image storage unit 5.
A labeling process is performed on the image data, and the weld defect determining unit 8 calculates a feature amount for each of the labeled regions.
Further, the nugget N is specified from among the labeled regions based on the feature amount calculated by the weld defect determining unit 8, and the welding position detecting unit 6 calculates the center position of the nugget N. Thus, in the laser welding defect inspection apparatus and the defect inspection method according to the present embodiment, the positioning table 1 can be moved based on the calculated center position, and the inspection object 50 is previously arranged at a predetermined position by the positioning table 1. Inspection of the inspection object 50 can be performed without the need.

[0029]

According to the laser welding defect inspection apparatus and the defect inspection method of the present invention, the welding position detecting section detects the position of the central portion (nugget) N of the welding section using the image data of the inspection object. Nugget N detected by labeling processing unit
And a labeling process for the peripheral portion. Furthermore, for each region where the weld defect determination unit is labeled,
A predetermined feature amount is calculated from the position coordinates, it is determined whether or not the nugget N is formed in an appropriate shape based on the calculated feature amount, and it is checked whether or not a defective portion has occurred. Thereby, in the laser welding defect inspection apparatus and the defect inspection method of the present invention, not only the through-hole generated in the inspection object, but also unnecessary holes such as holes and dents generated in the surface of the inspection object on the laser welding side. The lysed part can be detected. Furthermore, with the laser welding defect inspection apparatus and the defect inspection method of the present invention, it is possible to automatically determine a decrease in welding strength due to the above-mentioned melted portion, and to perform a defect inspection of the inspection object with high accuracy. Become.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a laser welding defect inspection apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a positional relationship among an inspection object, an illuminator, and a television camera shown in FIG.

FIG. 3 is an explanatory diagram showing an example of an image of an inspection object having no defect portion imaged by the television camera shown in FIG. 1;

FIG. 4 is an explanatory diagram showing an example of an image of an inspection object having a defective portion captured by the television camera shown in FIG. 1;

FIG. 5 is an enlarged view in which the defective portion shown in FIG. 4 is enlarged;

FIG. 6 is a flowchart showing the operation of the laser welding defect inspection device shown in FIG. 1;

FIG. 7 is a flowchart showing the operation of the laser welding defect inspection apparatus according to the second embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a conventional laser welding defect inspection apparatus.

9 is a flowchart showing the operation of the laser welding defect inspection device shown in FIG.

[Explanation of symbols]

 Reference Signs List 1 positioning table 2 illuminator 3 television camera 4 laser welding defect inspection processing unit 5 image storage unit 6 welding position detection unit 7 labeling processing unit 8 welding defect detection unit 9 main controller

 ──────────────────────────────────────────────────の Continuing on the front page (72) Noriyuki Suzuki, Inventor 1006, Kazuma, Kadoma, Osaka Prefecture F-term (reference) 2F065 AA03 AA15 AA17 AA49 AA51 BB05 CC00 CC15 FF42 GG17 HH12 HH14 HH16 JJ03 JJ09 JJ19 PP12 QQ00 QQ03 QQ04 QQ21 QQ24 QQ25 QQ28 RR05 TT02 2G051 AA73 AA90 AB13 BB01 CA04 CB01 DA07 EA12 EA14 EA16 ED04 ED11 GC04 GD02 GD03 5B057 AA01 BA02 CA08 CA12 CA16 DC03 DA03 DB09 DB09

Claims (4)

[Claims] An image input device that captures an image of an inspection target from above and generates image data of a grayscale image thereof; an illuminator arranged above the inspection target to illuminate the inspection target; A welding position detecting unit that detects a central portion of a welding portion using image data from an image input device; a labeling processing unit that performs a labeling process on the central portion detected by the welding position detecting unit and a peripheral portion thereof; and the labeling. A predetermined feature amount is calculated for each region labeled by the processing unit, and based on the calculated feature amount, a welded part defect determination unit that determines a non-defective product or a defective product of the inspection object. A laser welding defect inspection apparatus, characterized in that: 2. The apparatus according to claim 1, wherein the illuminator illuminates the inspection object such that light reflected from a peripheral portion of the central portion does not directly enter the image input device. The described laser welding defect inspection device. 3. The laser welding defect inspection apparatus according to claim 1, wherein the welding position detection unit detects a center position of the center portion on the grayscale image. 4. A generating step of capturing an image of an inspection object from above and generating image data of a grayscale image thereof; a detecting step of detecting a central portion of a welded portion using the image data generated in the generating step; A labeling step of performing a labeling process on the central portion and its peripheral portion detected in the detection step, and for each region labeled in the labeling step,
A predetermined feature amount is calculated, and based on the calculated feature amount,
A determining step of determining a non-defective or defective product to be inspected.