JP2004191070A - Coated surface inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve accuracy in inspecting a coated surface (accuracy in detecting a protrusion part, a recession part, etc. in the coated surface) in a coated surface inspection apparatus. <P>SOLUTION: The coated surface inspection apparatus is provided with: a contrast pattern 8 opposed to the coated surface; an irradiation means for irradiating the coated surface with inspecting light based on the contrast pattern 8 from the contrast pattern 8; and an imaging means 4 for imaging the contrast pattern 8 by receiving the inspecting light irradiated from the irradiation means and reflected at the coated surface. The focus of the imaging means 4 is matched with the location of the contrast pattern 8, and the coated surface is inspected on the basis of the result of edge processing based on imaging data received by the imaging means 4. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a painted surface inspection apparatus for inspecting a surface state of a painted surface.
[0002]
[Prior art]
For example, as an inspection device for inspecting a painted surface of an automobile body, as disclosed in Patent Documents 1 and 2, for example, a light and dark pattern (3, 2c in FIGS. 1 and 2 of Patent Document 1) is applied to a painted surface. An inspection unit (2a in FIG. 2 of Patent Document 1) is provided so as to oppose and irradiates an inspection light based on the light and dark pattern from the light and dark pattern to the painted surface. Some include an imaging unit (5 in FIG. 1 of Patent Document 1) that receives light to image a light and dark pattern.
[0003]
With this configuration, the light-dark pattern reflected on the painted surface is imaged by the imaging means, and the painted surface is inspected based on the result of the edge processing based on the image data received by the imaging means. In this case, according to Patent Literatures 1 and 2, for example, as shown in FIG. 6, since the light-dark pattern 8 reflected on the painted surface H is imaged by the imaging means 4, the focus G of the imaging means 4 is focused on the painted surface H. I have.
[0004]
[Patent Document 1]
JP-A-8-145906 (FIGS. 1 and 2)
[Patent Document 2]
JP-A-9-126744 (FIGS. 1, 3, 4, and 5)
[0005]
[Problems to be solved by the invention]
Inspection of a painted surface generally involves detecting a convex portion, a concave portion, or the like of the painted surface. In this case, the projections and the like of the painted surface are relatively large (for example, having a height of 50 to 70 μm), whereas the concaves and the like of the painted surface are relatively small (for example, having a depth of 20 μm). ３０30 μm). As a result, when the focus of the imaging unit is focused on the painted surface as in Patent Documents 1 and 2, the convex portions and the like of the painted surface are detected, but the concave portions and the like of the painted surface are hard to be detected. Therefore, there is room for improvement in terms of improving the inspection accuracy of the painted surface (detection accuracy of a convex portion, a concave portion, or the like of the painted surface).
An object of the present invention is to improve the inspection accuracy of a painted surface (detection accuracy of a convex portion, a concave portion, or the like of a painted surface) in a painted surface inspection apparatus.
[0006]
[Means for Solving the Problems]
[I]
When inspecting the painted surface based on the result of the edge processing based on the imaging data received by the imaging means, a boundary portion between a high-luminance portion corresponding to a light portion of the light-dark pattern and a low-luminance portion corresponding to a dark portion of the light-dark pattern. However, the clearer the paint (the less blurred and undisturbed), the greater the difference between the high-brightness portion corresponding to the light portion of the light-dark pattern and the low-brightness portion corresponding to the dark portion of the light-dark pattern, The inspection accuracy of the surface (the detection accuracy of a convex portion, a concave portion, or the like on the painted surface) is high.
[0007]
According to the features of claim 1, a light-dark pattern arranged to face the painted surface, an irradiating means for irradiating the painted surface with the inspection light based on the light-dark pattern from the light-dark pattern, and an inspection radiated from the irradiating means and reflected on the painted surface The imaging device is provided with an imaging unit that captures a light-dark pattern by receiving light, and focuses the imaging unit on the position of the light-dark pattern, and inspects the painted surface based on a result of edge processing based on imaging data received by the imaging unit. It is composed.
[0008]
Thus, according to the first aspect of the present invention, for example, as shown in FIG. 5, the focus G of the imaging means 4 is adjusted not to the painted surface H but to the light and dark pattern 8 located earlier than the painted surface H. The imaging means 4 can obtain imaging data of the light and dark pattern 8 before being attenuated or scattered on the surface H.
[0009]
As in the feature of claim 1, if imaging data of a light-dark pattern in a state before being attenuated or scattered on the painted surface can be obtained by the imaging means, in the imaging data received by the imaging means, a light portion of the light-dark pattern can be obtained. The boundary between the corresponding high-luminance part and the low-luminance part corresponding to the dark part of the light-dark pattern becomes clearer than in the case where the imaging unit is focused on the painted surface as in Patent Documents 1 and 2. The brightness of the high-brightness portion corresponding to the bright portion of the light-dark pattern is higher than that in the case where the imaging unit is focused on the painted surface as in Patent Documents 1 and 2 (the brightness of the light-dark pattern). The difference between the high-brightness portion corresponding to the portion and the low-brightness portion corresponding to the dark portion of the light-dark pattern becomes large).
[0010]
[II]
According to the feature of the second aspect, similar to the case of the first aspect, the "operation" described in the above [I] is provided, and in addition, the following "operation" is provided.
As a method of processing the image data received by the imaging means, there is generally a binarization process. The binarization process can detect whether or not a convex portion or a concave portion exists on the painted surface, but it is difficult to accurately detect the scale of the convex portion or the concave portion on the painted surface.
[0011]
According to the second aspect of the present invention, in the imaging data received by the imaging means, a high-luminance portion corresponding to a bright portion of the light-dark pattern, a low-luminance portion corresponding to a dark portion of the light-dark pattern, and high and low luminances. And a means for discriminating a portion having an intermediate luminance between them, so as to inspect the painted surface.
Thus, according to the second aspect of the present invention, the intermediate luminance portion is determined, and the intermediate luminance portion is determined as a convex portion or a concave portion of the painted surface, so that the scale of the convex portion or the concave portion of the painted surface can be accurately determined. Good detection becomes possible.
[0012]
In this case, in the imaging data received by the imaging means as described in [I] above, a boundary portion between a high-luminance portion corresponding to a bright portion of the light-dark pattern and a low-luminance portion corresponding to a dark portion of the light-dark pattern. And that the high-brightness part corresponding to the light part of the light-dark pattern has a large luminance (the high-brightness part corresponding to the light part of the light-dark pattern and the darkness of the light-dark pattern). The difference between the low-brightness part and the low-brightness part corresponding to the part is large.) It becomes easier to detect the scale of the projections and depressions (accurately performed).
[0013]
[III]
According to the feature of the third aspect, similar to the case of the second aspect, the "action" described in the above [I] and [II] is provided, and in addition, the following "action" is provided.
According to a third aspect of the present invention, there is provided a brightness difference detecting means for detecting a brightness difference between a high brightness portion corresponding to a bright portion of a light and dark pattern and an intermediate brightness portion in the image data received by the imaging means.
[0014]
In the case of a convex part or a concave part of the painted surface, the intermediate luminance changes according to the height of the convex part of the painted surface or the depth of the concave part of the painted surface. The present applicant was able to confirm that there is a correlation between the depth of the concave portion and the like and the intermediate luminance). By detecting the luminance difference between the luminance portion and the intermediate luminance portion, it is possible to detect the height of the convex portion and the like of the painted surface and the depth of the concave portion and the like of the painted surface.
[0015]
[IV]
According to the feature of claim 4, like the case of claim 2 or 3, it has the “action” described in the preceding items [I] to [III], and additionally has the following “action” in addition to this. ing.
According to a fourth aspect of the present invention, there is provided a range detecting means for detecting a range of an intermediate luminance portion.
[0016]
When it is determined that the intermediate luminance portion is a convex portion or a concave portion of the painted surface, there is a correlation between the range of the intermediate luminance portion and the size (length) of the convex portion or the concave portion of the painted surface. According to the feature of claim 4, if the intermediate luminance portion is judged to be a convex portion or a concave portion of the painted surface, the range of the intermediate luminance portion is detected. By doing so, it is possible to detect the size (length) of a convex portion, a concave portion, or the like of the painted surface.
[0017]
[V]
According to the feature of claim 5, like the case of any one of claims 1 to 4, the “action” described in the above items [I] to [IV] is provided, and in addition to this, It has various "actions".
In addition to the projections and depressions, a state in which minute irregularities continue alternately may occur on the painted surface, and such a state is generally called “yuzu skin”. This is a state in which the concentration of the paint is not constant due to eddy convection generated when the paint solvent evaporates, and minute irregularities are periodically and alternately generated in the thickness of the coating film.
[0018]
According to the fifth aspect of the present invention, there is provided a cycle detecting means for detecting a cycle of a change of the image data received by the image sensing means, and a comparing means for comparing the cycle detected by the cycle detecting means with a reference cycle.
In this case, with respect to the period of the change of the imaging data received by the imaging means on the normal painted surface (for example, the period of a high luminance portion corresponding to the light and dark pattern and a low luminance portion corresponding to the dark portion of the light and dark pattern). The applicant confirms that the change cycle (for example, the cycle between the high-brightness part and the low-brightness part) of the imaging data received by the imaging means on the painted surface of “yuzu skin” is different. I was able to.
[0019]
Thus, according to the fifth aspect of the present invention, if the period of the change of the imaging data received by the imaging unit on the normal painted surface is set as the reference period, the period detected by the period detection unit is compared with the reference period. Therefore, if the cycle detected by the cycle detecting means and the reference cycle are the same, it can be determined that the surface is a normal painted surface, and the cycle detected by the cycle detecting means and the reference cycle are different. If there is, it can be determined that it is the painted surface of "Yuzu skin".
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a state of inspection of a painted surface of a body 1 in an automobile. The painted body 1 is conveyed by a conveyor 2 to the left in the drawing. The irradiation device 3 is arranged on the upper side of the conveyor 2 (the right side of the paper of FIG. 1), and the imaging device 4 (for example, a CCD camera) is arranged on the lower side of the conveyor 2 (the left side of the paper of FIG. 1). And an inspection device for the painted surface.
[0021]
As shown in FIG. 1, the irradiation device 3 is arranged in a direction A1 at 45 ° on the upstream side of the conveyor 2 with respect to a direction A0 orthogonal to the conveyance direction of the conveyor 2, and the irradiation device 3 is orthogonal to the direction A1. It is arranged in the state to be. The imaging device 4 is arranged in a direction A2 at 45 ° on the lower side of the conveyor 2 with respect to the direction A0, and the imaging device 4 is arranged to be orthogonal to the direction A2. The distance B1 between the irradiation device 3 and the body 1 and the distance B2 between the imaging device 4 and the body 1 are set to be, for example, about 250 mm.
[0022]
As shown in FIG. 2, the irradiation device 3 includes a box-shaped outer frame portion 5, a light source 6 (for example, a fluorescent lamp) provided inside the outer frame portion 5, a diffusion plate 7 (for example, ground glass), and a light-dark pattern 8 and the like. It is configured with. The light-dark pattern 8 is configured such that black stripes are arranged at predetermined intervals on a transparent or translucent plate member, and the transparent or translucent portion becomes a bright portion 8a, and the black stripe portion becomes a dark portion 8b. Become. In this case, the width of the light portion 8a and the width of the dark portion 8b of the light and dark pattern 8 are set to, for example, 2 to 3 mm.
[0023]
As shown in FIG. 1, a control unit 9, an image processing device 10, a computer 11, a monitor 12, and the like are provided for the imaging device 4. In this case, as shown in FIG. 1, the imaging device 4 is configured to image the light-dark pattern 8 through the painted surface of the body 1 (in the irradiation device 3, the inspection light is emitted from the light source 6 to the light-dark pattern 8). The imaging device 4 is configured to irradiate the painted surface of the body 1 with the inspection light reflected by the painted surface of the body 1 via the imaging device 4), and to focus the imaging device 4 on the position of the light-dark pattern 8. (See FIG. 5).
[0024]
In the inspection apparatus for the painted surface as described above, as shown in FIG. 1, as the body 1 is transported to the left of the paper by the conveyor 2, the imaging device 4 is moved through the painted surface of the body 1 as described above. To capture an image of the light and dark pattern 8 (configured such that the imaging device 4 is focused on the position of the light and dark pattern 8).
[0025]
As a result, as shown in FIGS. 3A and 3B, the image data received by the imaging device 4 undergoes edge processing (eg, ternary processing) by the image processing device 10, and is applied to the light portion 8a of the light / dark pattern 8. A corresponding portion C1 of the high luminance K1, a portion C2 of the low luminance K2 corresponding to the dark portion 8b of the light-dark pattern 8, and a portion C3 of the intermediate luminance K3 between the high luminance K1 and the low luminance K2 are determined. FIG. 3A is a plan view of the image data received by the image capturing apparatus 4, and FIG. 3B is a cross-sectional view taken along the line D <b> 1-D <b> 1 of FIG.
[0026]
In this case, since the focus of the imaging device 4 is set to the position of the light-dark pattern 8, as shown in FIGS. 3A and 3B, the high-luminance K1 portion C1 corresponding to the light portion 8a of the light-dark pattern 8 And a boundary portion between the low-luminance K2 portion C2 corresponding to the dark portion 8b of the light-dark pattern 8 becomes clear and the high-luminance K1 portion C1 corresponding to the light portion 8a of the light-dark pattern 8 has a high luminance. (The difference between the portion C1 of the high brightness K1 corresponding to the light portion 8a of the light and dark pattern 8 and the portion C2 of the low brightness K2 corresponding to the dark portion 8b of the light and dark pattern 8 becomes large).
[0027]
As shown in FIGS. 3 (a) and 3 (b), for a normal portion on the painted surface of the body 1, a portion C1 of high luminance K1 is obtained corresponding to the bright portion 8a of the bright / dark pattern 8, and the bright / dark pattern is obtained. A portion C2 of low luminance K2 is obtained corresponding to the dark portion 8b of No. 8. In a portion of the painted surface of the body 1 where a convex portion or a concave portion of the painted surface is present, the inspection light is irregularly reflected, and a portion C3 of an intermediate luminance K3 between the high luminance K1 and the low luminance K2 is obtained. The portion C3 of the brightness K3 can be determined as a convex portion, a concave portion, or the like of the painted surface of the body 1.
[0028]
As shown in FIGS. 3A and 3B, a brightness difference K13 between a portion C1 of the high brightness K1 corresponding to the light portion 8a of the light and dark pattern 8 and a portion C3 of the middle brightness K3 is detected. The intermediate brightness K3 changes according to the height of the convex portion of the painted surface of the body 1 and the depth of the concave portion of the painted surface of the body 1 (the height of the convex portion of the painted surface of the body 1 and the height of the body 1). It is confirmed in advance that there is a correlation between the depth of the concave portion or the like of the painted surface and the intermediate luminance K3), and as described above, the high luminance K1 corresponding to the light portion 8a of the light / dark pattern 8 is obtained. By detecting the luminance difference K13 between the portion C1 and the portion C3 of the intermediate luminance K3, it is possible to detect the height of the convex portion and the like of the painted surface of the body 1 and the depth of the concave portion and the like of the painted surface of the body 1. .
[0029]
As shown in FIGS. 3A and 3B, a portion other than the portion C3 of the intermediate luminance K3 is compared with a portion C3 of the intermediate luminance K3 in the direction D1-D1 to correspond to the portion C3 of the intermediate luminance K3. By counting the number of high-intensity K1 portions C1 corresponding to the light portions 8a of the light-dark pattern 8 (or the number of low-intensity K2 portions C2 corresponding to the dark portions 8b of the light-dark pattern 8) in the portion, The length L1 in the D1-D1 direction of the portion C3 of K3 can be detected. Thus, the size (length) of the convex portion, the concave portion, and the like of the painted surface of the body 1 can be detected from the length L1 in the D1-D1 direction of the portion C3 of the intermediate luminance K3.
[0030]
Next, detection of the painted surface of the body 1 of “yuzu skin” will be described.
As shown in FIG. 4, when image data received by the imaging device 4 is subjected to edge processing (eg, ternary processing) by the image processing device 10, a light-dark pattern 8 is applied to a normal portion on the painted surface of the body 1. A portion C1 of the high luminance K1 corresponding to the bright portion 8a of FIG. 4 is obtained, and a portion C2 of the low luminance K2 corresponding to the dark portion 8b of the light / dark pattern 8 is obtained. In this case, the number of the high-intensity K1 portions C1 corresponding to the light portions 8a of the light-dark pattern 8 in the predetermined length L2 is known in advance, and the high-intensity K1 portions C1 corresponding to the light portions 8a of the light-dark pattern 8 are known. Is grasped as the reference period S1.
[0031]
Thereby, as shown in FIG. 4, when the image data received by the imaging device 4 is subjected to edge processing (ternary processing or the like) by the image processing device 10, an intermediate luminance K3 between the high luminance K1 and the low luminance K2 is obtained. Is obtained, the number of peaks of the portion C3 of the intermediate luminance K3 at the predetermined length L2 is counted, and the change period S2 of the portion C3 of the intermediate luminance K3 is detected. In this case, the period of change (for example, the period between a high-brightness part and a low-brightness part) of the imaging data received by the imaging unit 4 on the painted surface of the “yuzu skin” body 1 is different from the reference period S1. Has been confirmed in advance.
[0032]
Therefore, as shown in FIG. 4, by comparing the period S2 of the change of the portion C3 of the intermediate luminance K3 with the reference period S1, the period S2 of the change of the portion C3 of the intermediate luminance K3 is different from the reference period S1. If this is the case (generally, the period S2 of the change of the portion C3 of the intermediate luminance K3 is longer than the reference period S1), it can be determined that the painted surface of the body 1 is “yuzu skin”.
[0033]
【The invention's effect】
According to the feature of the first aspect, in the inspection apparatus for the painted surface, the focus of the imaging means is set not on the painted surface but on a light / dark pattern located earlier than the painted surface, so that the imaging data received by the imaging means has a light / dark pattern. The boundary between the high-brightness part corresponding to the bright part and the low-brightness part corresponding to the dark part of the light-dark pattern becomes clear, and the high-brightness part corresponding to the bright part of the light-dark pattern has high brightness (The difference between the high luminance part corresponding to the light part of the light and dark pattern and the low luminance part corresponding to the dark part of the light and dark pattern becomes large), and the inspection accuracy of the painted surface (the convexity of the painted surface) (Accuracy of detecting a part, a concave part, and the like).
Thus, according to the features of the first aspect, it is possible to detect not only the convex portions and the like of the painted surface but also the concave portions and the like of the painted surface smaller than the convex portions and the like of the painted surface.
[0034]
According to the feature of the second aspect, similar to the case of the first aspect, the "effect of the invention" of the above-described claim 1 is provided. It has.
According to the features of the second aspect, in the imaging data received by the imaging means, a point of determining an intermediate luminance portion between high luminance and low luminance is determined, and in the imaging data received by the imaging means, a bright portion of a light-dark pattern is determined. The boundary between the high-luminance part corresponding to the low-luminance part corresponding to the dark part of the light-dark pattern is clear, and the high-luminance part corresponding to the light part of the light-dark pattern has high luminance. (The point where the difference between the high-brightness part corresponding to the bright part of the light-dark pattern and the low-brightness part corresponding to the dark part of the light-dark pattern is large) determines the part of the intermediate luminance. As a result, it is possible to determine a portion having an intermediate luminance as a convex portion or a concave portion of the painted surface, and to accurately detect the scale of the convex portion or the concave portion of the painted surface.
As a result, if it is possible to accurately detect the scale of the convex portion or the concave portion of the painted surface as in the feature of the second aspect, for example, the coating process and the scale of the convex portion or the concave portion of the painted surface may be reduced. This makes it easier to analyze the causal relationship of the above, which is advantageous in terms of quality control of the painted surface.
[0035]
According to the feature of the third aspect, similar to the case of the second aspect, the present invention has the “effect of the invention” of the second aspect, and in addition to the “effect of the invention”, the following “effect of the invention” It has.
According to the feature of claim 3, by detecting the luminance difference between the high luminance portion corresponding to the light portion of the light and dark pattern and the intermediate luminance portion, the height of the convex portion of the painted surface or the concave portion of the painted surface is detected. It becomes possible to detect the depth, for example, it becomes easier to analyze the causal relationship between the painting process and the height of the convexities and the like of the painted surface and the depth of the concaves and the like of the painted surface, and the like. This is advantageous in terms of quality control.
[0036]
According to the feature of claim 4, the "effect of the invention" of the above-mentioned claim 2 or 3 is provided similarly to the case of the claim 2 or 3, and in addition to the "effect of the invention", the following " Effect of the Invention ".
According to the feature of the fourth aspect, the size (length) of the convex portion or the concave portion of the painted surface is determined by judging the portion of the intermediate luminance as a convex portion or a concave portion of the painted surface and detecting the range of the intermediate luminance portion. ) Can be detected, and it becomes easy to analyze, for example, the causal relationship between the painting process and the size (length) of a convex portion or a concave portion of the painted surface, and the quality of the painted surface. This is advantageous in terms of management.
[0037]
According to the feature of claim 5, the "effect of the invention" of the above-mentioned claims 1 to 4 is provided similarly to the case of any one of the claims 1 to 4, and in addition to the "effect of the invention" The following "effects of the invention" are provided.
According to the feature of claim 5, by detecting the period of the change of the imaging data received by the imaging means, the painted surface of “Yuzu skin” can be appropriately detected, and the coating of “Yuzu skin” can be performed. The surface detection accuracy could be improved. This makes it easier to analyze, for example, the causal relationship between the painting process and the painted surface of “Yuzu skin”, which is advantageous in terms of quality control of the painted surface.
[Brief description of the drawings]
FIG. 1 is a plan view showing an outline of a coating surface inspection apparatus. FIG. 2 is an exploded perspective view of an irradiation apparatus. FIG. 3 is an image processing apparatus that performs edge processing (such as ternarization processing) on image data received by an imaging apparatus. Figure showing the projections (projections and depressions on the painted surface of the body)
FIG. 4 is a diagram showing image data received by an image pickup device subjected to edge processing (ternary processing, etc.) by an image processing device (painted surface of a body of “Yuzu skin”)
FIG. 5 is a diagram showing a state of imaging by an imaging unit in the present invention; FIG. 6 is a diagram showing a state of imaging by an imaging unit in a conventional technique;
Reference Signs List 4 imaging means 8 light and dark pattern 8a light and dark pattern bright part 8b light and dark pattern dark part 6 irradiation means C1 high luminance part C2 corresponding to the light and dark pattern light part C2 low luminance part C3 corresponding to the light and dark pattern dark part C3 high luminance Part G having an intermediate luminance between light and low luminance G Focus H of the imaging means Painting surface K1 High luminance K2 corresponding to the light part of the light-dark pattern Low luminance K3 corresponding to the dark part of the light-dark pattern Between high luminance and low luminance The intermediate luminance K13 The luminance difference L1 between the high luminance part and the intermediate luminance part L1 The range of the intermediate luminance part S1 Reference cycle S2 Cycle of the change of the imaging data received by the imaging means

Claims (5)

A light-dark pattern arranged to face the painted surface, an irradiating means for irradiating the painted surface with the inspection light based on the light-dark pattern from the light-dark pattern, and an inspecting light irradiated from the irradiating means and reflected by the painted surface Image pickup means for receiving the light and dark pattern in response to the
An apparatus for inspecting a painted surface, wherein the focus of the imaging unit is adjusted to a position of the light and dark pattern, and the painted surface is inspected based on a result of edge processing based on imaging data received by the imaging unit. In the imaging data received by the imaging unit, a high-luminance portion corresponding to a bright portion of the light-dark pattern, a low-luminance portion corresponding to a dark portion of the light-dark pattern, and a portion between the high luminance and the low luminance The painted surface inspection apparatus according to claim 1, further comprising a discriminating means for discriminating an intermediate luminance portion, wherein the painted surface is inspected. 3. The painted surface inspection apparatus according to claim 2, further comprising a luminance difference detecting unit that detects a luminance difference between the high luminance portion and the intermediate luminance portion. 4. The inspection apparatus for a painted surface according to claim 2, further comprising a range detection unit configured to detect a range of the intermediate luminance portion. 5. 5. The apparatus according to claim 1, further comprising: a cycle detection unit configured to detect a cycle of a change in the image data received by the imaging unit; and a comparison unit configured to compare a cycle detected by the cycle detection unit with a reference cycle. The painted surface inspection apparatus according to any one of the above.

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