JP2008216199A - Device and method for inspecting weld bead - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for inspecting a weld bead enabling a reduction in the time required for inspecting for the presence or the absence of the defect of the weld beads. <P>SOLUTION: The images 6 of the predetermined areas to which a line pattern 4 is emitted are photographed, while emitting the line pattern 4 formed of line beams 5, 5, ..., which are generally parallel to are another to the predetermined areas including the surface of the weld bead 3 to be inspected. The images 6 are linearized, to generate a fine line image 7. A reference fine line image as a pre-generated fine line image is compared with the fine line image 7, generated by a fine line image generating part 111b for the defect-free weld bead to calculate the coincidence thereof. Based on the calculated agree, the presence or absence of the defects on the surface of the weld bead 3 to be inspected is determined. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for inspecting a weld bead and thus determining whether the welding quality is good or bad.

Conventionally, as a method for determining the quality of welding by welding, that is, the quality of welding quality, there is a method for determining the presence or absence of a weld bead defect by visually inspecting its shape while an operator illuminates the weld bead. Are known.
However, such a method has a problem that inspection results vary depending on the proficiency level of the worker and the work environment, and the physical burden on the worker is large, and there is a limit to improvement in work efficiency.
As another method, there is a method in which an operator actually measures the size of a defect on the surface of the weld bead using a gauge or the like, but there is a problem that the operation is complicated.
In addition, there is a method of extracting and cutting a part of the inspection object and observing the cut surface, but such a method is not applicable to the 100% inspection, and the time required until the inspection result is obtained. There is a problem that the time lag when feeding back the inspection result to the manufacturing process is large because it is long.

  As a method for solving the above-described problem, there is known a method for determining the quality of welding quality by irradiating a welding bead with slit light and using a light-cut image by reflected light of the slit light. For example, as described in Patent Document 1.

However, the method described in Patent Document 1 has a problem that it takes a long time to inspect the entire length of the weld bead.
This is because the optical cutting line by the slit light irradiated to the weld bead is single, and only a single cross section of the single weld bead can be obtained by one imaging, so the cross sectional shape over the entire length of the weld bead. In order to acquire the image, it is necessary to perform image acquisition (imaging) a great number of times while shifting the irradiation position of the slit light, and it takes a lot of time to process the acquired cross-sectional shape data. .
Japanese Unexamined Patent Publication No. 6-94640

  In view of the circumstances as described above, the present invention provides a weld bead inspection device and an inspection method capable of reducing the time required for inspection for the presence or absence of defects in a weld bead.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, in claim 1,
A line pattern irradiation unit that irradiates a predetermined pattern including a surface of the weld bead to be inspected with a plurality of line lights that are substantially parallel to each other;
An imaging unit that captures an image of a predetermined region irradiated with the line pattern by the line pattern irradiation unit;
A thinned image generating unit that generates a thinned image by linearizing an image captured by the imaging unit;
A matching degree calculation unit that calculates a degree of matching between the reference thinned image that is a thinned image generated in advance for a weld bead having no defect and the thinned image generated by the thinned image generating unit; ,
A determination unit that determines the presence or absence of defects on the surface of the weld bead to be inspected based on the degree of coincidence calculated by the degree of coincidence calculation unit;
It comprises.

In claim 2,
The determination unit
When the coincidence degree calculated by the coincidence degree calculating unit is out of a predetermined range, it is determined that the surface of the weld bead to be inspected has a defect.

In claim 3,
A line pattern irradiation unit that irradiates a predetermined pattern including a surface of the weld bead to be inspected with a plurality of line lights that are substantially parallel to each other;
An imaging unit that captures an image of a predetermined region irradiated with the line pattern by the line pattern irradiation unit;
A thinned image generating unit that generates a thinned image by linearizing an image captured by the imaging unit;
A line number calculating unit for calculating the number of lines in the thinned image generated by the thinned image generating unit;
A determination unit for determining the presence or absence of defects on the surface of the weld bead to be inspected based on the number of lines calculated by the line number calculation unit;
It comprises.

In claim 4,
The determination unit
When the number of lines calculated by the line number calculation unit is larger than a predetermined number of lines, it is determined that there is a defect on the surface of the weld bead to be inspected.

In claim 5,
A line pattern irradiation unit that irradiates a predetermined pattern including a surface of the weld bead to be inspected with a plurality of line lights that are substantially parallel to each other;
An imaging unit that captures an image of a predetermined region irradiated with the line pattern by the line pattern irradiation unit;
A thinned image generating unit that generates a thinned image by linearizing an image captured by the imaging unit;
The cross-sectional shape feature amount for calculating the cross-sectional shape feature amount of the weld bead to be inspected, which is composed of the phase spectrum of each column element corresponding to the dominant line pitch of the line in the thinned image generated by the thinned image generation unit A calculation unit;
A determination unit for determining the presence or absence of defects on the surface of the weld bead to be inspected based on the cross-sectional shape feature amount calculated by the cross-sectional shape feature amount calculation unit;
It comprises.

In claim 6,
The determination unit
A non-defective cross-sectional shape feature amount calculated in advance for a weld bead having no defect or a non-defective cross-sectional shape feature amount calculated in advance for a plurality of weld beads having typical defects. Whether or not there is a defect on the surface of the weld bead to be inspected is determined by performing pattern matching between either one or both and the cross-sectional shape feature amount calculated by the cross-sectional shape feature amount calculation unit. .

In claim 7,
An imaging process for capturing an image of a predetermined area irradiated with the line pattern while irradiating a predetermined pattern including a plurality of line lights substantially parallel to the predetermined area including the surface of the weld bead to be inspected;
A thinned image generation step of generating a thinned image by linearizing the image captured in the imaging step;
A degree-of-matching calculation step of calculating a degree of matching between the reference thinned image, which is a thinned image generated in advance for a weld bead having no defect, and the thinned image generated in the thinned image generating step; ,
A determination step of determining the presence or absence of defects on the surface of the weld bead to be inspected based on the degree of coincidence calculated in the coincidence degree calculating step;
It comprises.

In claim 8,
The determination step includes
When the coincidence degree calculated in the coincidence degree calculating step is outside a predetermined range, it is determined that the surface of the weld bead to be inspected has a defect.

In claim 9,
An imaging process for capturing an image of a predetermined area irradiated with the line pattern while irradiating a predetermined pattern including a plurality of line lights substantially parallel to the predetermined area including the surface of the weld bead to be inspected;
A thinned image generation step of generating a thinned image by linearizing the image captured in the imaging step;
A line number calculating step of calculating the number of lines in the thinned image generated in the thinned image generating step;
A determination step of determining the presence or absence of defects on the surface of the weld bead to be inspected based on the number of lines calculated in the line number calculation step;
It comprises.

In claim 10,
The determination step includes
When the number of lines calculated in the line number calculating step is larger than a predetermined number of lines, it is determined that the surface of the weld bead to be inspected has a defect.

In claim 11,
An imaging process for capturing an image of a predetermined area irradiated with the line pattern while irradiating a predetermined pattern including a plurality of line lights substantially parallel to the predetermined area including the surface of the weld bead to be inspected;
A thinned image generation step of generating a thinned image by linearizing the image captured in the imaging step;
The cross-sectional shape feature value for calculating the cross-sectional shape feature value of the weld bead to be inspected consisting of the phase spectrum of each column element corresponding to the dominant line pitch of the line in the thinned image generated in the thinned image generation step A calculation process;
A determination unit that determines the presence or absence of defects on the surface of the weld bead to be inspected based on the cross-sectional shape feature amount calculated in the cross-sectional shape feature amount calculation step;
It comprises.

In claim 12,
The determination step includes
A non-defective cross-sectional shape feature amount calculated in advance for a weld bead having no defect or a non-defective cross-sectional shape feature amount calculated in advance for a plurality of weld beads having typical defects. Whether or not there is a defect on the surface of the weld bead to be inspected is determined by performing pattern matching between one or both of them and the cross-sectional shape feature amount calculated in the cross-sectional shape feature amount calculation step. .

  The present invention has an effect that it is possible to shorten the time required for the inspection for the presence or absence of defects in the weld bead.

Hereinafter, an inspection apparatus 100 which is a first embodiment of the inspection apparatus for weld beads according to the present invention will be described with reference to FIGS. 1 to 4.
The inspection apparatus 100 inspects a weld bead 3 in a steel plate in which the steel plates 1 and 2 are butt welded, and mainly includes a line pattern irradiation device 10, an imaging device 20, and a control device 110.
In addition, although the inspection apparatus 100 of a present Example inspects the weld bead 3 which butt-welded the steel plates 1 and 2, this invention is not limited to this, It is applicable to the inspection of various weld beads. .

The line pattern irradiation apparatus 10 is an embodiment of a line pattern irradiation unit according to the present invention, and a plurality of line lights 5, 5,... Substantially parallel to a predetermined region including the surface of the weld bead 3 to be inspected. The line pattern 4 comprising:
The line pattern irradiation apparatus 10 mainly includes a laser pointer 11 and a multiline diffraction grating 12.

The laser pointer 11 generates and projects red laser light. The laser pointer 11 may be a dedicated product, but it is also possible to achieve this using a commercially available product.
Although the laser pointer 11 of the present embodiment is configured to generate red laser light, the present invention is not limited to this, and other visible light, infrared light, or the like may be used as long as imaging can be performed by an imaging unit described later. However, the line light is preferably visible light from the viewpoint of easily confirming that the line pattern is irradiated on the predetermined region.
The multi-line diffraction grating 12 is an optical element for generating a line pattern 4 by separating the laser light projected from the laser pointer 11 into a plurality of line lights 5.

  The line pattern 4 is irradiated to a “predetermined region” including the steel plate 1 and the steel plate 2 with the weld bead 3 interposed therebetween. Further, each of the line lights 5, 5... Constituting the line pattern 4 has one end located on the steel plate 1 and the other end located on the steel plate 2. Therefore, the line lights 5, 5... Are irradiated so as to straddle the weld beads 3.

The imaging device 20 is an embodiment of an imaging unit according to the present invention. As shown in FIG. 2A and FIG. 3A, a predetermined region irradiated with the line pattern 4 by the line pattern irradiation device 10 is shown. The image 6 is captured.
The imaging device 20 mainly includes an imaging device main body 21, a camera lens 22, a band pass filter 23, and a polarization filter 24.

  The imaging device main body 21 has an imaging element such as a CCD camera or a CMOS camera, for example, and takes an image 6. The imaging device main body 21 may be a dedicated product, but it is also possible to achieve this using a commercially available product.

  The camera lens 22 converges light (reflected light) from a predetermined region including the surface of the weld bead 3 on the image pickup device of the image pickup apparatus main body 21.

The bandpass filter 23 transmits only a predetermined wavelength band component of light (reflected light) from a predetermined region including the surface of the weld bead 3 and does not transmit other components, thereby removing a noise component. It is a filter.
The bandpass filter 23 is provided at a position that covers the field of view of the camera lens 22 (and thus the field of view of the imaging device 20).

The polarizing filter 24 is a light component (reflected light) from a predetermined region including the surface of the weld bead 3 except for the reflected light of the line light 5 · 5. This is a filter for blocking light from the light source.
The polarizing filter 24 is provided at a position that covers the field of view of the camera lens 22 (and thus the field of view of the imaging device 20).

In the case of the present embodiment, the imaging device 20 has the line pattern 4 disposed above a “predetermined region” including the steel plate 1 and the steel plate 2 with the weld bead 3 interposed therebetween, and the plate surfaces of the steel plates 1 and 2 in the predetermined region. The image 6 is picked up from a direction substantially perpendicular to. Further, the line pattern irradiation device 10 is disposed on the side of the imaging device 20 (a position where the line pattern irradiation device 10 and the imaging device 20 do not interfere with each other), and irradiates the line pattern 4 obliquely from above on a predetermined region.
Although the imaging apparatus 20 of the present embodiment is configured to include the bandpass filter 23 and the polarization filter 24, the present invention is not limited to this, and the imaging environment (the ambient lighting conditions, the surface state of the inspection object, etc.) ), These may be omitted.

An image 6 shown in FIG. 2A is an image obtained by capturing a predetermined area including only a portion of the weld bead 3 having no defect (blow hole, melt-through, through hole, undercut, etc.), and constitutes a line pattern 4. The line light 5 · 5... That is adjacent to the weld bead 3 is curved along the shape of the weld bead 3 (the shape raised from the surfaces of the steel plates 1 and 2). -The interval of 5 is substantially the same.
An image 6 shown in FIG. 3A is an image obtained by imaging a predetermined region including a portion having a defect in the weld bead 3, and corresponds to a defect among the line lights 5, 5... Constituting the line pattern 4. The degree of curvature is different between the line light 5 that crosses the portion to be covered (the portion surrounded by the dotted line in FIG. 3A) and the line light 5 that crosses the portion that does not correspond to the defect. The intervals between the matching line lights 5 and 5 are different.

  The control device 110 mainly includes a control unit 111, an input unit 112, a display unit 113, and the like.

The control unit 111 controls a series of operations of the inspection apparatus 100.
The control unit 111 stores various programs and the like (for example, an inspection operation control program, a thinned image generation program, a coincidence degree calculation program, a determination program, and various data described later), expands these programs, and the like. It is possible to perform a predetermined calculation according to the above program and store (store) the calculation result and the like.

The control unit 111 may actually be configured such that a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like.
Although the control unit 111 of this embodiment is a dedicated product, it can also be achieved by storing the above-described program in a commercially available personal computer or workstation.

The control unit 111 is connected to the laser pointer 11 of the line pattern irradiation device 10 and can transmit a signal for operating the line pattern irradiation device 10 (projecting and stopping the laser beam).
The control unit 111 is connected to the imaging device 20 and can transmit a signal for operating the imaging device 20 (capturing the image 6), and the image 6 (line pattern 5) captured by the imaging device 20 can be transmitted. It is possible to acquire an image of a predetermined area irradiated with

The input unit 112 is connected to the control unit 111 and inputs various information / instructions related to the operation of the inspection apparatus 100 to the control unit 111.
Although the input unit 112 of the present embodiment is a dedicated product, the same effect can be achieved even by using a commercially available keyboard, mouse, pointing device, button, switch, or the like.

The display unit 113 displays the operation status of the inspection apparatus 100, the input content from the input unit 112 to the control unit 111, the inspection result by the inspection apparatus 100, and the like.
Although the display unit 113 of this embodiment is a dedicated product, the same effect can be achieved even if a commercially available monitor, liquid crystal display, or the like is used.

  Moreover, it is possible to achieve what integrated the function as the input part 112 and the function as the display part 113 using a commercially available touch panel etc. FIG.

Below, the detailed structure of the control part 111 is demonstrated.
Functionally, the control unit 111 includes an inspection operation control unit 111a, a thin line image generation unit 111b, a coincidence degree calculation unit 111c, and a determination unit 111d.

The inspection operation control unit 111a controls the operation of the inspection apparatus 100.
Substantially, the control unit 111 functions as the inspection operation control unit 111a by performing a predetermined calculation or the like according to the inspection operation control program stored in advance.

  In the present embodiment, the inspection apparatus 100 is disposed in the middle of the conveyance path along which the steel plates butt-welded to the steel plates 1 and 2 are conveyed along the longitudinal direction of the weld bead 3. The “predetermined region” in which the line pattern 4 is irradiated each time the steel plate butt welded to the length of the welding bead 3 in the longitudinal direction of the “predetermined region including the surface 3” is conveyed. Get an image. In this way, the weld bead 3 is imaged over the entire length.

The thinned image generation unit 111b generates a thinned image by linearizing the image captured by the imaging device 20.
Substantially, the control unit 111 performs a predetermined calculation or the like in accordance with a thinned image generation program stored in advance, thereby functioning as the thinned image generation unit 111b.

As shown in FIGS. 2 and 3, the thinned image generator 111 b linearizes an image 6 of a predetermined region including the surface of the weld bead 3 imaged by the imaging device 20 to generate a linearized image 7. is there.
“Linearization” is a kind of image processing, and generally refers to converting a linear figure on an image into a line having a line width of one pixel.
By linearizing the image 6, the line lights 5, 5... Constituting the line pattern 4 in the image 6 pass through the center position in the line width direction of the corresponding line light 5 in the linearized image 7. It is converted into linearized lines 8, 8.
In this embodiment, the thinned image generation unit 111b sets each of the linearized lines 8, 8... As a function Y (i) (i = 1, 2,..., N (N is a positive integer)). Convert to coordinate data.

  In this embodiment, the image 6 is linearized as it is to generate the linearized image 7. However, the present invention is not limited to this, and the image is subjected to predetermined image processing such as expansion processing and contraction processing. It is good also as a structure which linearizes later and produces | generates a linearized image.

The degree-of-match calculation unit 111c compares the “reference thinned image”, which is a thinned image generated in advance for a weld bead having no defect, and the thinned image 8 generated by the thinned image generating unit 111b. The degree of coincidence between the thinned image and the thinned image 8) is calculated.
Substantially, the control unit 111 functions as the coincidence degree calculating unit 111c by performing a predetermined calculation or the like according to a coincidence degree calculating program stored in advance.

The control unit 111 is a thinned image generated by linearizing an image of a weld bead that has been confirmed in advance by other methods (visual observation, observation of a cut surface, scanning with an eddy current sensor, etc.). The “reference thinned image” is stored as data. The “reference thinned image” is converted into coordinate data as a function X (i) (i = 1, 2,..., N (N is a positive integer)).
The coincidence calculation unit 111c uses the function X (i) of the “reference thinned image” and the function Y (i) of the thinned image 7 generated by the thinned image generation unit 111b, and is expressed by the following equation (1). A cross-correlation value Rxy (k) is calculated. Here, k represents a positive integer from 1 to N, and N is the number of line lights 5 · 5... Represented in the image 6 (more strictly, the number when the light is not cut off in the middle). Represents.

  As shown in FIG. 4, when the horizontal axis is k and the vertical axis is plotted as the calculated cross-correlation value Rxy (k), when a predetermined area including only a portion having no defect in the weld bead 3 is imaged (black circle, The transition of the cross-correlation value Rxy (k) is different between the case where a predetermined region including a defective part in the weld bead 3 is picked up (white circle, see FIG. 3).

  In the present embodiment, the coincidence calculation unit 111c calculates the cross-correlation value of the linearized line in the linearized image as the “coincidence”. A configuration using another generally known index may be used.

The determination unit 111d determines whether or not there is a defect on the surface of the weld bead 3 to be inspected based on the degree of coincidence calculated by the degree of coincidence calculation unit 111c.
Substantially, the control unit 111 functions as the determination unit 111d by performing a predetermined calculation or the like according to a determination program stored in advance.

  The control unit 111 determines that the “reference thinned image” and the image from which the reference thinned image is based have a different field of view and have no defects (or have defects within an allowable range) (for example, visually). Between a plurality of linearized images (thinned images for setting a predetermined range) created from a plurality of images of a weld bead that has been confirmed by observation of a cut surface of the weld bead, scanning by an eddy current sensor, etc. An upper limit value and a lower limit value (R1 and R2 in FIG. 4) of a predetermined range of “matching degree when there is no defect” set based on the calculated matching value are stored in advance.

  In the present embodiment, the upper limit value R1 of the predetermined range is obtained by adding a predetermined constant to the maximum value of the degree of coincidence calculated between the “reference thinned image” and the “thinned image for setting the predetermined range”. The lower limit value R2 of the predetermined range is a value obtained by subtracting a predetermined constant from the minimum value of the degree of coincidence calculated between the “reference thinned image” and the “predetermined range setting thinned image”. However, for example, an upper limit value and a lower limit value in a predetermined range may be set by theoretical calculation based on a dimensional tolerance of the weld bead.

  The determination unit 111d has a predetermined range of the degree of coincidence calculated by the degree of coincidence calculation unit 111c (in the case of the present embodiment, among the cross-correlation values Rxy (k), Rxy (N) that is a value when k = N). If it is within (R2 ≦ Rxy (N) ≦ R1), it is determined that there is no defect on the surface of the portion of the weld bead 3 imaged in the image 6, and if it is outside the predetermined range (Rxy (N ) <R2 or R1 <Rxy (N)), it is determined that the surface of the portion of the weld bead 3 imaged in the image 6 has a defect.

  The determination result by the determination unit 111d is stored in the control unit 111. Further, it is displayed on the display unit 113 as necessary, or transmitted to another device.

As described above, the inspection apparatus 100 is
A line pattern irradiating apparatus 10 that irradiates a predetermined pattern including a surface of the weld bead 3 to be inspected with a line pattern 4 composed of a plurality of line lights 5, 5.
An imaging device 20 that captures an image 6 of a predetermined region irradiated with the line pattern 4 by the line pattern irradiation device 10;
A thinned image generation unit 111b that linearizes the image 6 captured by the imaging device 20 to generate a thinned image 7,
By comparing the reference thinned image, which is a thinned image generated in advance for a weld bead having no defect, and the thinned image 7 generated by the thinned image generating unit 111b, both (reference thinned image and thinned image 7) are compared. ) Of the degree of coincidence calculating unit 111c,
A determination unit 111d that determines the presence or absence of defects on the surface of the weld bead 3 to be inspected based on the degree of coincidence calculated by the coincidence degree calculation unit 111c;
It comprises.
In addition, the determination unit 111d
When the coincidence degree calculated by the coincidence degree calculating unit 111c is out of the predetermined range, it is determined that the surface of the weld bead 3 to be inspected has a defect.
With this configuration, the inspection apparatus 100 can inspect whether or not the surface of the weld bead 3 has a defect in the field of view (predetermined region) of the image device 20 at a time.
Therefore, it is possible to reduce the time required for the inspection of the presence or absence of defects in the weld bead 3 as compared with the conventional inspection apparatus that performs inspection while scanning the weld bead in the longitudinal direction with one line light.
Further, since the inspection is performed based on the thinned image (thinned image), it is possible to reduce the influence of the luminance unevenness of the inspection target in the inspection, and the inspection accuracy, that is, the determination accuracy of the presence / absence of a defect can be achieved. improves.

Below, the 1st Example of the inspection method of the weld bead based on this invention is described using FIG. 1 and FIG.
The first embodiment of the method for inspecting a weld bead according to the present invention is a method for inspecting a weld bead 3 in a steel plate in which the steel plates 1 and 2 are butt-welded, and as shown in FIG. 5, mainly an imaging step S1100, a linearized image. A generation step S1200, a matching degree calculation step S1300, and a determination step S1400 are provided.

In the imaging step S1100, the line pattern 4 was irradiated while irradiating a predetermined pattern including the surface of the weld bead 3 to be inspected with the line pattern 4 composed of a plurality of line lights 5, 5,. This is a step of capturing an image 6 of a predetermined area.
In the imaging step S1100, the line pattern irradiation apparatus 10 irradiates a predetermined pattern including a surface of the weld bead 3 to be inspected with a line pattern 4 composed of a plurality of line lights 5, 5,. The imaging device 20 captures an image 6 of a predetermined area irradiated with the line pattern 4 by the line pattern irradiation device 10.
When the imaging step S1100 is completed, the process proceeds to a linearized image generation step S1200.

The linearized image generation step S1200 is a step of generating the thinned image 7 by linearizing the image 6 captured in the imaging step S1100.
In the linearized image generation step S1200, the thinned image generation unit 111b linearizes the image 6 of a predetermined region including the surface of the weld bead 3 imaged by the imaging device 20 to generate the linearized image 7, and linearly Are converted into coordinate data as functions Y (i) (i = 1, 2,..., N (N is a positive integer)).
When the linearized image generation step S1200 is completed, the process proceeds to a coincidence degree calculation step S1300.

In the coincidence calculation step S1300, the “reference thinned image” which is a thinned image generated in advance for a weld bead having no defect and the thinned image 8 generated in the linearized image generating step S1200 are compared with each other (reference This is a step of calculating the degree of coincidence between the thinned image and the thinned image 8).
In the coincidence calculation step S1300, the coincidence calculation unit 111c linearizes an image of a weld bead that has been confirmed in advance by other methods (visual observation, observation of a cut surface, scanning with a eddy current sensor, etc.). A cross-correlation value Rxy (k) is calculated between the “reference thinned image” that is the generated thinned image and the thinned image 7 generated by the thinned image generation unit 111b, and this is calculated as the reference thinned image. And the degree of coincidence between the thinned images 8.
When the coincidence calculation step S1300 is completed, the process proceeds to a determination step S1400.

The determination step S1400 is a step of determining the presence or absence of a defect on the surface of the weld bead 3 to be inspected based on the coincidence degree calculated in the coincidence degree calculation step S1300.
In determination step S1400, determination unit 111d compares a predetermined range of cross-correlation values set in advance with cross-correlation value Rxy (N) calculated in coincidence calculation step S1300, and cross-correlation value Rxy (N) is determined. If it is within the predetermined range, it is determined that there is no defect on the surface of the portion of the weld bead 3 captured in the image 6, and if it is outside the predetermined range, the image is captured in the image 6 of the weld bead 3. It is determined that there is a defect on the surface of the portion that has been processed.

As described above, by configuring the first embodiment of the method for inspecting a weld bead according to the present invention, it is possible to inspect a predetermined region at a time whether or not there is a defect on the surface of the weld bead 3.
Therefore, it is possible to reduce the time required for the inspection of the presence or absence of defects in the weld bead 3 as compared with the conventional inspection apparatus that performs inspection while scanning the weld bead in the longitudinal direction with one line light.
Further, since the inspection is performed based on the thinned image (thinned image), it is possible to reduce the influence of the luminance unevenness of the inspection target in the inspection, and the inspection accuracy, that is, the determination accuracy of the presence / absence of a defect can be achieved. improves.

Below, the inspection apparatus 200 which is the 2nd Example of the inspection apparatus of the weld bead based on this invention is demonstrated using FIG.1, FIG.6 and FIG.7.
The inspection device 200 inspects the weld bead 3 in the steel plate in which the steel plates 1 and 2 are butt-welded, and mainly includes the line pattern irradiation device 10, the imaging device 20, and the control device 210.
Note that the basic configurations of the line pattern irradiation apparatus 10 and the imaging apparatus 20 of the present embodiment are substantially the same as those in the inspection apparatus 100, and thus detailed description thereof is omitted.

The control device 210 mainly includes a control unit 211, an input unit 212, a display unit 213, and the like.
Note that the basic configurations of the input unit 212 and the display unit 213 of the present embodiment are substantially the same as those in the inspection apparatus 100, and thus detailed description thereof is omitted.

The control unit 211 controls a series of operations of the inspection apparatus 200.
The control unit 211 stores various programs and the like (for example, an inspection operation control program, a thinned image generation program, a line number calculation program, a determination program, and various data described later), expands these programs, and the like. It is possible to perform a predetermined calculation according to the above program and store (store) the calculation result and the like.

The control unit 211 may actually have a configuration in which a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like.
Although the control unit 211 of this embodiment is a dedicated product, it can also be achieved by storing the above-described program in a commercially available personal computer or workstation.

The control unit 211 is connected to the laser pointer 11 of the line pattern irradiation apparatus 10 and can transmit a signal for operating the line pattern irradiation apparatus 10 (projecting and stopping the laser beam).
In addition, the control unit 211 is connected to the imaging device 20 and can transmit a signal for operating the imaging device 20 (capturing the image 6), and the image 6 (line pattern 5) captured by the imaging device 20 can be transmitted. It is possible to acquire an image of a predetermined area irradiated with

Below, the detailed structure of the control part 211 is demonstrated.
Functionally, the control unit 211 includes an inspection operation control unit 211a, a thinned image generation unit 211b, a line number calculation unit 211c, and a determination unit 211d.
Note that the basic configuration of the inspection operation control unit 211a of the present embodiment is substantially the same as that in the inspection apparatus 100, and thus detailed description thereof is omitted.

The thinned image generation unit 211b linearizes the image 6 captured by the imaging device 20 to generate the thinned image 7.
Substantially, the control unit 211 performs a predetermined calculation or the like according to a thinned image generation program stored in advance, thereby functioning as a thinned image generation unit 211b.

As shown in FIGS. 6 and 7, the thinned image generator 211 b linearizes the image 6 of a predetermined region including the surface of the weld bead 3 imaged by the imaging device 20 to generate a linearized image 7. is there.
By linearizing the image 6, the line lights 5, 5... Constituting the line pattern 4 in the image 6 pass through the center position in the line width direction of the corresponding line light 5 in the linearized image 7. It is converted into linearized lines 8, 8.

The line number calculating unit 211c calculates the number of lines (linearized lines 8, 8...) In the thinned image 7 generated by the thinned image generating unit 211b.
Substantially, the control unit 211 performs a function as the line number calculation unit 211c by performing a predetermined calculation in accordance with a line number calculation program stored in advance.

The line number calculation unit 211c calculates the number of linearized lines 8, 8... Included in the thinned image 7 by labeling the thinned image 7.
“Labeling” is a kind of image processing. In the present embodiment, the linear lines included in the linearized image are regarded as connected figures (digitally connected figures), and each connected figure has a different number. To assign a label consisting of
The line number calculation unit 211c calculates the maximum value of the labels assigned to the linearized lines 8 included in the thinned image 7 and the number of linearized lines 8 included in the thinned image 7. To do.

  As shown in FIG. 6, when a predetermined region including only a portion having no defect is imaged in the weld bead 3, the number of line lights 5, 5... Included in the image 6 and the linearization in the linearized image 7. The number of lines 8, 8... Is the same, N.

As shown in FIG. 7, when an image of a predetermined region including a defective part in the weld bead 3 is imaged, the number of line lights 5, 5... Included in the image 6 and the linearity included in the linearized image 7. The number of control lines 8, 8... Is different. This is because the luminance in the image 6 of the portion corresponding to the defect is reduced for the line light 5 that crosses the portion having the defect in the weld bead 3, and when this is linearized, the portion where the luminance is reduced is connected. This is because it is not recognized and is converted into a plurality of linearization lines (the linearization lines are disconnected).
In the case of FIG. 7, the number of line lights 5 · 5 ··· included in the image 6 is N, but the number of linearization lines 8 · 8 ··· included in the linearized image 7 is (N + 5). It is.

  In the present embodiment, the number of linearized lines 8, 8... Is calculated by labeling the linearized image 7. However, the present invention is not limited to this, and the linearity is obtained using other methods. It is also possible to employ a configuration for calculating the number of control lines.

The determination unit 211d determines the presence or absence of defects on the surface of the weld bead 3 to be inspected based on the number (number) of linearized lines 8, 8,... Calculated by the line number calculation unit 211c.
Substantially, the control unit 211 functions as the determination unit 211d by performing a predetermined calculation or the like according to a determination program stored in advance.

The control unit 211 is a thinned image generated by linearizing an image of a weld bead that has been confirmed in advance by other methods (such as visual observation, observation of a cut surface, and scanning by an eddy current sensor). “Number of linearized lines included in reference thinned image (in this example, N lines)” calculated by labeling “reference thinned image” is stored as data of “predetermined number of lines”. is doing.
The determination unit 211d has the same number of linearization lines 8, 8,... Calculated by the line number calculation unit 211c as the “number of linearization lines included in the reference thinned image” (see FIG. 6). Is determined that there is no defect on the surface of the portion of the weld bead 3 imaged in the image 6, and the number of linearized lines 8, 8... Calculated by the line number calculation unit 211c is “reference thinning”. When the number is larger than “the number of linearization lines included in the image” (see FIG. 7), it is determined that the surface of the portion of the weld bead 3 captured in the image 6 has a defect.

  The determination result by the determination unit 211d is stored in the control unit 211. Further, it is displayed on the display unit 213 as necessary, or transmitted to another device.

As described above, the inspection apparatus 200 is
A line pattern irradiating apparatus 10 that irradiates a predetermined pattern including a surface of the weld bead 3 to be inspected with a line pattern 4 composed of a plurality of line lights 5, 5.
An imaging device 20 that captures an image 6 of a predetermined region irradiated with the line pattern 4 by the line pattern irradiation device 10;
A thinned image generation unit 211b that linearizes the image 6 captured by the imaging device 20 to generate a thinned image 7,
A line number calculating unit 211c for calculating the number of linearized lines 8, 8... In the thinned image 7 generated by the thinned image generating unit 211b;
A determination unit 211d that determines the presence or absence of defects on the surface of the weld bead 3 to be inspected based on the number of linearized lines 8, 8... Calculated by the line number calculation unit 211c;
It comprises.
In addition, the determination unit 211d
When the number of lines (linearized lines 8, 8...) Calculated by the line number calculation unit 211c is larger than a predetermined number of lines, it is determined that there is a defect on the surface of the weld bead 3 to be inspected. is there.
With this configuration, the inspection apparatus 200 can inspect whether or not there is a defect on the surface of the weld bead 3 at once in the field of view (predetermined region) of the image device 20.
Therefore, it is possible to reduce the time required for the inspection of the presence or absence of defects in the weld bead 3 as compared with the conventional inspection apparatus that performs inspection while scanning the weld bead in the longitudinal direction with one line light.
Further, since the inspection is performed based on the thinned image (thinned image), it is possible to reduce the influence of the luminance unevenness of the inspection target in the inspection, and the inspection accuracy, that is, the determination accuracy of the presence / absence of a defect can be achieved. improves.

Below, the 2nd Example of the inspection method of the weld bead based on this invention is described using FIG. 1 and FIG.
The second embodiment of the method for inspecting a weld bead according to the present invention is a method for inspecting a weld bead 3 in a steel plate in which the steel plates 1 and 2 are butt-welded, and as shown in FIG. 8, mainly an imaging step S2100, a linearized image. A generation step S2200, a line number calculation step S2300, and a determination step S2400 are provided.

In the imaging step S2100, the line pattern 4 is irradiated while irradiating a predetermined region including the surface of the weld bead 3 to be inspected with the line pattern 4 composed of a plurality of line lights 5, 5,. This is a step of capturing an image 6 of a predetermined area.
In the imaging step S2100, the line pattern irradiation device 10 irradiates a predetermined pattern including a surface of the weld bead 3 to be inspected with a line pattern 4 composed of a plurality of line lights 5, 5. The imaging device 20 captures an image 6 of a predetermined area irradiated with the line pattern 4 by the line pattern irradiation device 10.
When the imaging step S2100 is completed, the process proceeds to a linearized image generation step S2200.

The linearized image generation step S2200 is a step of generating the thinned image 7 by linearizing the image 6 captured in the imaging step S2100.
When the linearized image generation step S2200 ends, the process proceeds to the line number calculation step S2300.

The line number calculating step S2300 is a step of calculating the number of lines (linearized lines 8, 8...) In the thinned image 7 generated in the thinned image generating step S2200.
When the line number calculation step S2300 is completed, the process proceeds to a determination step S2400.

The determination step S2400 is a step of determining the presence / absence of a defect on the surface of the weld bead 3 to be inspected based on the number (number) of linearized lines 8.8,... Calculated in the line number calculation step S2300.
In the determination step S2400, the determination unit 211d determines that the number of linearization lines 8.8,... Calculated by the line number calculation unit 211c is the same as the “number of linearization lines included in the reference thinned image”. Determines that the surface of the portion of the weld bead 3 imaged in the image 6 is free of defects, and the number of linearized lines 8, 8... Calculated by the line number calculation unit 211c is “reference thinned image”. If there are more than the “number of linearization lines included in”, it is determined that the surface of the portion of the weld bead 3 imaged in the image 6 has a defect.

As described above, by configuring the second embodiment of the method for inspecting a weld bead according to the present invention, it is possible to inspect a predetermined region at a time whether or not there is a defect on the surface of the weld bead 3.
Therefore, it is possible to reduce the time required for the inspection of the presence or absence of defects in the weld bead 3 as compared with the conventional inspection apparatus that performs inspection while scanning the weld bead in the longitudinal direction with one line light.
Further, since the inspection is performed based on the thinned image (thinned image), it is possible to reduce the influence of the luminance unevenness of the inspection target in the inspection, and the inspection accuracy, that is, the determination accuracy of the presence / absence of a defect can be achieved. improves.

Below, the inspection apparatus 300 which is the 3rd Example of the inspection apparatus of the weld bead based on this invention is demonstrated using FIG.1, FIG.9, FIG.10, FIG.11 and FIG.
The inspection device 300 inspects the weld bead 3 in the steel plate in which the steel plates 1 and 2 are butt-welded, and mainly includes the line pattern irradiation device 10, the imaging device 20, and the control device 310.
Note that the basic configurations of the line pattern irradiation apparatus 10 and the imaging apparatus 20 of the present embodiment are substantially the same as those in the inspection apparatus 100, and thus detailed description thereof is omitted.

The control device 310 mainly includes a control unit 311, an input unit 312, a display unit 313, and the like.
Note that the basic configurations of the input unit 312 and the display unit 313 of the present embodiment are substantially the same as those in the inspection apparatus 100, and thus detailed description thereof is omitted.

The control unit 311 controls a series of operations of the inspection apparatus 300.
The control unit 311 stores various programs and the like (for example, an inspection operation control program, a thinned image generation program, a cross-sectional shape feature amount calculation program, a determination program, and various data described later), and develops these programs. A predetermined calculation can be performed in accordance with these programs, and the calculation result or the like can be stored (stored).

The control unit 311 may actually have a configuration in which a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like.
Although the control unit 311 of this embodiment is a dedicated product, it can also be achieved by storing the above-described program in a commercially available personal computer or workstation.

The control unit 311 is connected to the laser pointer 11 of the line pattern irradiation device 10 and can transmit a signal for operating the line pattern irradiation device 10 (projecting and stopping the laser beam).
The control unit 311 is connected to the imaging device 20 and can transmit a signal for operating the imaging device 20 (capturing the image 6), and the image 6 captured by the imaging device 20 (line pattern 5). It is possible to acquire an image of a predetermined area irradiated with

Below, the detailed structure of the control part 311 is demonstrated.
Functionally, the control unit 311 includes an inspection operation control unit 311a, a thin line image generation unit 311b, a cross-sectional shape feature value calculation unit 311c, and a determination unit 311d.
Note that the basic configuration of the inspection operation control unit 311a of the present embodiment is substantially the same as that in the inspection apparatus 100, and thus detailed description thereof is omitted.

The thinned image generating unit 311b generates the thinned image 7 by linearizing the image 6 captured by the imaging device 20.
Substantially, the control unit 311 performs a predetermined calculation or the like in accordance with a thinned image generation program stored in advance, thereby fulfilling a function as the thinned image generation unit 311b.

As shown in FIGS. 9 and 10, the thinned image generation unit 311 b generates a linearized image 7 by linearizing an image 6 of a predetermined region including the surface of the weld bead 3 imaged by the imaging device 20. is there.
By linearizing the image 6, the line lights 5, 5... Constituting the line pattern 4 in the image 6 pass through the center position in the line width direction of the corresponding line light 5 in the linearized image 7. It is converted into linearized lines 8, 8.

  The linearized image 7 has a function f (Expression 2) shown below, where i is the coordinate in the vertical direction (corresponding to the longitudinal direction of the weld bead 3), and j is the coordinate in the horizontal direction (corresponding to the width direction of the weld bead 3). i, j).

The cross-sectional shape feature quantity calculation unit 311c is a phase spectrum of each column element corresponding to the dominant line pitch of the lines (linearized lines 8, 8...) In the thinned image 7 generated by the thinned image generating unit 311b. The “cross-sectional feature amount of the weld bead 3 to be inspected” is calculated.
Substantially, the control unit 311 performs a predetermined calculation or the like according to a prestored cross-sectional shape feature amount calculation program, thereby functioning as the cross-sectional shape feature amount calculation unit 311c.

  First, the cross-sectional shape feature value calculation unit 311c performs a discrete Fourier transform of each column element on the function f (i, j) representing the linearized image 7 to calculate a discrete Fourier function F (k, j). Here, k is a frequency index, and k = 0, 1,..., M−1.

  Next, the cross-sectional shape feature quantity calculation unit 311c calculates kmax, which is k when the function H (k) represented by the following Equation 3 takes the maximum value.

  The calculated kmax is a frequency index corresponding to the dominant line pitch in the linearized image 7. Here, the “dominant line pitch” is an interval between adjacent linearized lines in the linearized image, and corresponds to an interval between adjacent line lights in the captured image.

  Subsequently, the cross-sectional shape feature amount calculation unit 311c calculates the phase spectrum P (j) of each column element expressed by the following Equation 4 using kmax.

  P (j) is a phase spectrum of each column element when k = kmax, and is a cross-sectional shape that is a numerical value that serves as an index of the average cross-sectional shape of the corresponding image 6 and thus the weld bead 3 included in the predetermined region. Represents a feature quantity. Note that the unit of （F (kmax, j) is radians, and phase connection is performed.

  As shown in FIG. 11, when a predetermined region including only a portion having no defect in the weld bead 3 is imaged (see FIG. 9), the cross-sectional shape feature amount is a gently raised shape such as the cross-sectional shape of the weld bead 3. Become. On the other hand, the cross-sectional shape feature amount when a predetermined region including a portion having a defect in the weld bead 3 is imaged (see FIG. 10) has a shape in which a portion corresponding to the defect is recessed.

The determination unit 311d determines the presence / absence of a defect on the surface of the weld bead 3 to be inspected based on the cross-sectional shape feature P (j) calculated by the cross-sectional shape feature calculation unit 311c.
Substantially, the control unit 311 performs a predetermined calculation or the like according to a determination program stored in advance, thereby serving as the determination unit 311d.

The control unit 311 (A) thinning generated by linearizing an image of a weld bead that has been confirmed in advance by other methods (visual observation, observation of a cut surface, scanning with a eddy current sensor, etc.) that there is no defect. It has been confirmed by other methods that there is a “defective cross-sectional shape feature amount” that is a cross-sectional shape measurement amount calculated based on the “reference thinned image” that is an image, and (B) a typical defect. Stored as data are “defective product cross-sectional shape feature amounts”, which are a plurality of cross-sectional shape measurement amounts calculated based on a plurality of thinned images generated by linearizing images of a plurality of weld beads. .
The “defective product cross-sectional shape feature amount” is preferably calculated for each of the types of defects having different types, sizes, positions on the surface of the weld beads, and the like.

The determination unit 311d performs pattern matching (template matching) between the “non-defective cross-sectional shape feature amount” and the cross-sectional shape feature amount P (j) calculated by the cross-sectional shape feature amount calculation unit 311c, thereby obtaining the cross-sectional shape feature. It is determined whether or not the weld bead 3 included in the image 6 corresponding to the cross-sectional shape feature amount P (j) calculated by the amount calculation unit 311c has a defect.
If the determination unit 311d determines that there is a defect by pattern matching with the “non-defective cross-sectional shape feature amount”, the cross-sectional shape feature calculated by the “defective product cross-sectional shape feature amount” and the cross-sectional shape feature amount calculation unit 311c. By performing pattern matching with the amount P (j), the defect of the weld bead 3 included in the image 6 corresponding to the cross-sectional shape feature amount P (j) calculated by the cross-sectional shape feature amount calculation unit 311c is detected. The type, size, position on the surface of the weld bead, etc. are determined.
Note that any known pattern matching technique can be applied to the pattern matching technique according to the present invention.

  The determination result by the determination unit 311d is stored in the control unit 211. Further, it is displayed on the display unit 313 as necessary, or transmitted to another device.

As described above, the inspection apparatus 300 is
A line pattern irradiating apparatus 10 that irradiates a predetermined pattern including a surface of the weld bead 3 to be inspected with a line pattern 4 composed of a plurality of line lights 5, 5.
An imaging device 20 that captures an image 6 of a predetermined region irradiated with the line pattern 4 by the line pattern irradiation device 10;
A thinned image generating unit 311b that linearizes the image 6 captured by the imaging device 20 to generate a thinned image 7,
The weld bead 3 to be inspected consisting of the phase spectrum of each column element corresponding to the dominant line pitch of the lines (linearized lines 8, 8...) In the thinned image 7 generated by the thinned image generating unit 311b. A cross-sectional shape feature quantity calculation unit 311c that calculates the cross-sectional shape feature quantity P (j) of
A determination unit 311d for determining the presence or absence of defects on the surface of the weld bead 3 to be inspected based on the cross-sectional shape feature amount P (j) calculated by the cross-sectional shape feature amount calculation unit 311c;
It comprises.
In addition, the determination unit 311d
A non-defective cross-sectional shape feature amount that is a pre-calculated cross-sectional shape feature amount for a defect-free weld bead and a non-defective cross-sectional shape feature amount that is a pre-calculated cross-sectional shape feature amount for a plurality of weld beads having typical defects The presence or absence of defects on the surface of the weld bead 3 to be inspected is determined by performing pattern matching with the cross-sectional shape feature value P (j) calculated by the cross-sectional shape feature value calculation unit 311c.
With this configuration, the inspection apparatus 300 can inspect whether the surface of the weld bead 3 has a defect within the field of view (predetermined region) of the image device 20 at a time.
Therefore, it is possible to reduce the time required for the inspection of the presence or absence of defects in the weld bead 3 as compared with the conventional inspection apparatus that performs inspection while scanning the weld bead in the longitudinal direction with one line light.
Further, since the inspection is performed based on the thinned image (thinned image), it is possible to reduce the influence of the luminance unevenness of the inspection target in the inspection, and the inspection accuracy, that is, the determination accuracy of the presence / absence of a defect can be achieved. improves.

  In this embodiment, the pattern matching is performed between both the non-defective cross-sectional shape feature quantity and the defective cross-sectional shape feature quantity and the cross-sectional shape feature quantity P (j) calculated by the cross-sectional shape feature quantity calculating unit 311c. However, the present invention is not limited to this, and the configuration may be such that pattern matching is performed only between the non-defective cross-sectional shape feature value and the cross-sectional shape feature value calculated by the cross-sectional shape feature value calculating unit to determine the presence or absence of a defect. Alternatively, a configuration may be adopted in which pattern matching is performed only between the defective product cross-sectional shape feature value and the cross-sectional shape feature value calculated by the cross-sectional shape feature value calculating unit to determine the presence or absence of a defect.

In the present embodiment, the pattern matching is performed to determine the presence / absence of a defect. However, the present invention is not limited to this, and the presence / absence of a defect can be determined by applying an algorithm for detecting various defects. It is good also as a structure to determine.
As the above algorithm, for example, as shown in FIG. 12, an upper limit line and a lower limit line for a non-defective cross-sectional shape feature amount are set, and a cross-sectional shape feature amount calculated by the cross-sectional shape feature amount calculating unit protrudes from a region sandwiched between these. If it is, it is determined that it has a defect.

Hereinafter, a third embodiment of the inspection method for weld beads according to the present invention will be described with reference to FIGS. 1 and 13.
A third embodiment of the method for inspecting a weld bead according to the present invention is a method for inspecting a weld bead 3 in a steel plate in which the steel plates 1 and 2 are butt-welded, and as shown in FIG. 13, mainly an imaging step S3100, a linearized image. A generation step S3200, a cross-sectional shape feature amount calculation step S3300, and a determination step S3400 are provided.

In the imaging step S3100, the line pattern 4 is irradiated while irradiating a predetermined pattern including the surface of the weld bead 3 to be inspected with the line pattern 4 composed of a plurality of line lights 5, 5,. This is a step of capturing an image 6 of a predetermined area.
In the imaging step S3100, the line pattern irradiation apparatus 10 irradiates a predetermined pattern including a surface of the weld bead 3 to be inspected with a line pattern 4 composed of a plurality of line lights 5, 5,. The imaging device 20 captures an image 6 of a predetermined area irradiated with the line pattern 4 by the line pattern irradiation device 10.
When the imaging step S3100 is completed, the process proceeds to a linearized image generation step S3200.

The linearized image generation step S3200 is a step of generating the thinned image 7 by linearizing the image 6 imaged in the imaging step S3100.
When the linearized image generation step S3200 ends, the process proceeds to the cross-sectional shape feature amount calculation step S3300.

In the cross-sectional shape feature amount calculation step S3300, the phase spectrum of each column element corresponding to the dominant line pitch of the lines (linearized lines 8, 8...) In the thinned image 7 generated in the thinned image generating step S3200. Is a step of calculating “a cross-sectional shape feature amount of the weld bead 3 to be inspected”.
When the cross-sectional shape feature amount calculation step S3300 is completed, the process proceeds to the determination step S3400.

The determination step S3400 is a step of determining the presence or absence of a defect on the surface of the weld bead 3 to be inspected based on the cross-sectional shape feature amount P (j) calculated in the cross-sectional shape feature amount calculation step S3300.
In the determination step S3400, the determination unit 311d determines that the non-defective cross-sectional shape feature amount is a pre-calculated cross-sectional shape feature amount for a defect-free weld bead and the cross-sectional shape feature amount that is pre-calculated for a plurality of typical weld beads. By performing pattern matching between the defective sectional shape feature quantity and the sectional shape feature quantity P (j) calculated by the sectional shape feature quantity calculation unit 311c, defects on the surface of the weld bead 3 to be inspected are detected. Determine presence or absence.

As described above, by configuring the third embodiment of the method for inspecting a weld bead according to the present invention, it is possible to inspect a predetermined region at a time whether or not there is a defect on the surface of the weld bead 3.
Therefore, it is possible to reduce the time required for the inspection of the presence or absence of defects in the weld bead 3 as compared with the conventional inspection apparatus that performs inspection while scanning the weld bead in the longitudinal direction with one line light.
Further, since the inspection is performed based on the thinned image (thinned image), it is possible to reduce the influence of the luminance unevenness of the inspection target in the inspection, and the inspection accuracy, that is, the determination accuracy of the presence / absence of a defect can be achieved. improves.

The figure which shows the Example of the inspection apparatus of the weld bead which concerns on this invention. The figure which shows the captured image and linearized image about a weld bead without a defect. The figure which shows the captured image and linearized image about a weld bead with a defect. The figure which shows transition of a cross correlation value. The flowchart which shows the 1st Example of the inspection method of the weld bead which concerns on this invention. The figure which shows the captured image and linearized image about a weld bead without a defect. The figure which shows the captured image and linearized image about a weld bead with a defect. The flowchart which shows the 2nd Example of the inspection method of the weld bead which concerns on this invention. The figure which shows the captured image and linearized image about a weld bead without a defect. The figure which shows the captured image and linearized image about a weld bead with a defect. The figure which shows a cross-sectional shape feature-value. The figure which similarly shows a cross-sectional shape feature-value. The flowchart which shows the 3rd Example of the inspection method of the weld bead which concerns on this invention.

Explanation of symbols

1.2 Steel plate 3 Weld bead 4 Line pattern 5 Line light 6 Image 7 Linearization image 8 Linearization line 10 Line pattern irradiation device (line pattern irradiation unit)
20 Imaging device (imaging part)
100 Inspection device (first embodiment)
111b Thinned image generation unit 111c Matching degree calculation unit 111d Determination unit

Claims (12)

A line pattern irradiation unit that irradiates a predetermined pattern including a surface of the weld bead to be inspected with a plurality of line lights that are substantially parallel to each other;
An imaging unit that captures an image of a predetermined region irradiated with the line pattern by the line pattern irradiation unit;
A thinned image generating unit that generates a thinned image by linearizing an image captured by the imaging unit;
A matching degree calculation unit that calculates a degree of matching between the reference thinned image that is a thinned image generated in advance for a weld bead having no defect and the thinned image generated by the thinned image generating unit; ,
A determination unit that determines the presence or absence of defects on the surface of the weld bead to be inspected based on the degree of coincidence calculated by the degree of coincidence calculation unit;
A welding bead inspection apparatus comprising: The determination unit
The welding bead inspection device according to claim 1, wherein when the degree of coincidence calculated by the degree of coincidence calculation unit is out of a predetermined range, the surface of the weld bead to be inspected is determined to have a defect. A line pattern irradiation unit that irradiates a predetermined pattern including a surface of the weld bead to be inspected with a plurality of line lights that are substantially parallel to each other;
An imaging unit that captures an image of a predetermined region irradiated with the line pattern by the line pattern irradiation unit;
A thinned image generating unit that generates a thinned image by linearizing an image captured by the imaging unit;
A line number calculating unit for calculating the number of lines in the thinned image generated by the thinned image generating unit;
A determination unit for determining the presence or absence of defects on the surface of the weld bead to be inspected based on the number of lines calculated by the line number calculation unit;
A welding bead inspection apparatus comprising: The determination unit
The welding bead inspection device according to claim 3, wherein when the number of lines calculated by the line number calculation unit is greater than a predetermined number of lines, it is determined that there is a defect on the surface of the weld bead to be inspected. A line pattern irradiation unit that irradiates a predetermined pattern including a surface of the weld bead to be inspected with a plurality of line lights that are substantially parallel to each other;
An imaging unit that captures an image of a predetermined region irradiated with the line pattern by the line pattern irradiation unit;
A thinned image generating unit that generates a thinned image by linearizing an image captured by the imaging unit;
The cross-sectional shape feature amount for calculating the cross-sectional shape feature amount of the weld bead to be inspected, which is composed of the phase spectrum of each column element corresponding to the dominant line pitch of the line in the thinned image generated by the thinned image generation unit A calculation unit;
A determination unit for determining the presence or absence of defects on the surface of the weld bead to be inspected based on the cross-sectional shape feature amount calculated by the cross-sectional shape feature amount calculation unit;
A welding bead inspection apparatus comprising: The determination unit
A non-defective cross-sectional shape feature amount calculated in advance for a weld bead having no defect or a non-defective cross-sectional shape feature amount calculated in advance for a plurality of weld beads having typical defects. 6. The presence or absence of a defect on the surface of the weld bead to be inspected is determined by performing pattern matching between one or both of them and the cross-sectional shape feature amount calculated by the cross-sectional shape feature amount calculation unit. The welding bead inspection device described in 1. An imaging process for capturing an image of a predetermined area irradiated with the line pattern while irradiating a predetermined pattern including a plurality of line lights substantially parallel to the predetermined area including the surface of the weld bead to be inspected;
A thinned image generation step of generating a thinned image by linearizing the image captured in the imaging step;
A degree-of-matching calculation step of calculating a degree of matching between the reference thinned image, which is a thinned image generated in advance for a weld bead having no defect, and the thinned image generated in the thinned image generating step; ,
A determination step of determining the presence or absence of defects on the surface of the weld bead to be inspected based on the degree of coincidence calculated in the coincidence degree calculating step;
A method for inspecting a weld bead comprising: The determination step includes
The welding bead inspection method according to claim 7, wherein when the coincidence degree calculated in the coincidence degree calculating step is outside a predetermined range, it is determined that the surface of the weld bead to be inspected has a defect. An imaging process for capturing an image of a predetermined area irradiated with the line pattern while irradiating a predetermined pattern including a plurality of line lights substantially parallel to the predetermined area including the surface of the weld bead to be inspected;
A thinned image generation step of generating a thinned image by linearizing the image captured in the imaging step;
A line number calculating step of calculating the number of lines in the thinned image generated in the thinned image generating step;
A determination step of determining the presence or absence of defects on the surface of the weld bead to be inspected based on the number of lines calculated in the line number calculation step;
A method for inspecting a weld bead comprising: The determination step includes
The welding bead inspection method according to claim 9, wherein when the number of lines calculated in the line number calculation step is greater than a predetermined number of lines, it is determined that the surface of the inspection target weld bead has a defect. An imaging process for capturing an image of a predetermined area irradiated with the line pattern while irradiating a predetermined pattern including a plurality of line lights substantially parallel to the predetermined area including the surface of the weld bead to be inspected;
A thinned image generation step of generating a thinned image by linearizing the image captured in the imaging step;
The cross-sectional shape feature value for calculating the cross-sectional shape feature value of the weld bead to be inspected consisting of the phase spectrum of each column element corresponding to the dominant line pitch of the line in the thinned image generated in the thinned image generation step A calculation process;
A determination unit that determines the presence or absence of defects on the surface of the weld bead to be inspected based on the cross-sectional shape feature amount calculated in the cross-sectional shape feature amount calculation step;
A method for inspecting a weld bead comprising: The determination step includes
A non-defective cross-sectional shape feature amount calculated in advance for a weld bead having no defect or a non-defective cross-sectional shape feature amount calculated in advance for a plurality of weld beads having typical defects. The presence or absence of a defect on the surface of the weld bead to be inspected is determined by performing pattern matching between any one or both of them and the cross-sectional shape feature amount calculated in the cross-sectional shape feature amount calculation step. Inspection method of welding bead as described in 4.

Images