JP3095820B2 - Surface condition detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface condition detecting device, and more particularly, to a device for inspecting a surface to be inspected so as to have a predetermined light / dark gradient.
Are irradiated with light, the captures reflected light from the inspected surface to create a light image, the concave defect of the inspection surface based on brightness gradient change in the light receiving image, surface state detecting device for detecting a convex defects About.

[0002]

2. Description of the Related Art In a vehicle such as an automobile, the inspection of the surface condition of a painted surface, that is, the presence or absence of a coating defect on the painted surface is inspected after the painting of the vehicle body is completed.
As a technique for inspecting the surface condition of the painted surface or the like, for example, Japanese Patent Application Laid-Open No. 62-233710 discloses that a surface to be inspected of an inspection object is irradiated with light and the reflected light is projected on a screen. A technique for automatically detecting a surface defect on a surface to be inspected from the sharpness of the projected image is disclosed.

[0003]

By the way, as described above, light is emitted from the light source to the surface to be inspected, the reflected light is captured by a camera, and a light-receiving image is created. When detecting a surface defect on a surface, the camera itself appears in an image depending on the installation position of the camera, and it becomes difficult to inspect the surface defect for the reflected portion. Therefore, in order to prevent self-reflection of the camera, conventionally, as shown in FIG. 8, the camera 1 is arranged to be separated from the light source 2 and inclined. A received light image is created by capturing the reflected light, and a convex defect A and a concave defect A ′ on the inspection surface 3 are detected based on a change in brightness in the received light image. In this case, the camera 1 is inclined with respect to the surface 3 to be inspected, so that it is difficult to focus the image, and the image is distorted. Defect detection accuracy will be reduced.

Further, since the camera 1 and the light source 2 are arranged so as to be separated from each other, this type of surface state detecting device becomes large.

Accordingly, the present invention illuminates a surface to be inspected with a light source, captures reflected light from the surface to be inspected by a camera, creates a light-receiving image, and based on a change in brightness in the light-receiving image, forms a light-receiving image. An object of the present invention is to provide a device for inspecting the surface condition of a surface, in which self-reflection of the camera can be reliably prevented, inspection accuracy can be improved, and the entire device is configured to be more compact.

[0006]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized in that it is configured as follows.

First, the invention according to claim 1 of the present application (hereinafter referred to as “the invention”)
According to the first invention), the surface to be inspected has a predetermined brightness gradient in advance.
Irradiating light is set to be, to create a light image captures reflected light from the inspected surface, light in the light receiving image
A surface state detecting device for detecting a concave defect or a convex defect on a surface to be inspected based on a change in a dark gradient, a surface light source for irradiating inspection light to the surface to be inspected, and a central portion of the surface light source And a camera that captures reflected light from the surface to be inspected and creates a bright and dark light-receiving image according to the surface state of the inspection surface, and the camera in the surface light source emits inspection light from the surface light source. The luminous intensity is set so that the luminous intensity gradually increases concentrically from dark to bright from the center of the arrangement toward the periphery.

The invention according to claim 2 of the present application (hereinafter referred to as “the invention”)
In addition to the configuration of the above-described first aspect, the second aspect of the present invention includes a concave portion on the surface to be inspected by identifying a portion in the received light image created by the camera where the brightness is significantly different from the surroundings.
An image processing means for detecting a pit or a convex defect is provided.

[0009]

In accordance with the first invention, the inspection light of the surface light source is set as the luminous intensity in concentrically increases gradually from dark to bright towards the periphery than the center portion disposed camera of said surface light source A dark portion is formed at the center of the irradiation area on the surface to be inspected irradiated with the bright and dark light, and the camera is arranged at the center of the surface light source corresponding to the dark portion. Is prevented. If there is a surface defect in the irradiation area on the surface to be inspected, the state of reflection of bright and dark light at the site changes, and this state is captured by a camera arranged at the center of the surface light source. become. Therefore, it becomes possible to inspect the surface condition over the entire irradiation area on the surface to be inspected irradiated by the surface light source, and the inspection accuracy and inspection efficiency are improved.

Further, since the self-imaging of the camera disposed at the center of the surface light source is prevented, it is necessary to arrange the camera at an angle to the surface to be inspected in order to prevent the self-imaging. without this arrangement, the pin preparative <br/> alignment of the camera is obtained performed easily and very accurately, so that the distortion of the received-light image can be reliably prevented, it is assumed photodetection image is clearer, The detection accuracy of the surface state is further improved.

Further, since the camera is arranged at the center of the surface light source and the two are integrated, the whole inspection apparatus can be made more compact.

In particular, according to the second aspect, image processing for detecting a concave defect or a convex defect on a surface to be inspected by identifying a portion in a light-receiving image created by the camera whose brightness is significantly different from the surroundings. since means are provided, light in the light receiving image
The inspection accuracy is further improved as compared with the case where the surface state is inspected by visually identifying the change in the dark gradient .

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, near the vehicle body 10 transported to the painting inspection station S, a surface state detecting device 11 for inspecting a coating surface 10a of the vehicle body 10 to detect the presence or absence of a coating defect is provided. Are arranged, and this detection device 11
Has a robot device 13 mounted on a pedestal 12, and a light irradiating means 14 is attached to a tip arm 13 a of the robot device 13.
And a CCD camera 15 are attached via a support bracket 16. These light irradiating means 14 and the CCD camera 15 are attached to the surface of the vehicle body 10 carried into the painting station S,
That is, the coating surface 10a of the vehicle body 10 is traced, and at this time, the light irradiated by the light
The light is reflected by the coating film surface 10a and received by the CCD camera 15.

Further, the light irradiation means 14 and the CC
In the coating defect inspection by the D camera 15, the robot controller 18 is controlled by a command given by the host computer 17, and a signal from the robot controller 18 is sent to the robot device 13, and a predetermined signal built in the robot device 13 is transmitted. Is driven, whereby the robot apparatus 13 moves the light irradiating means 14 and the CCD camera 15 so as to follow the coating surface 10a of the vehicle body 10 and obtains the light by the CCD camera 15. The received light image is sent to the image processor 19. The image processor 19 amplifies and differentiates the video signal from the CCD camera 15, analyzes the differentiated signal, and transmits data indicating the result to the host computer 17. Thus, it is configured to detect the presence or absence of a coating defect on the coating surface 10a of the vehicle body 10, the coordinates of the defective portion, the shape of the coating defect, and the size thereof.

Next, the structure of the light irradiating means 14 will be described. As shown in FIG. 2, the light irradiating means 14 includes a plurality of light sources provided in a box 20 having one side opened. 21. Fluorescent lamps (not particularly limited to fluorescent lamps) 21 ... 21, an optical filter 22 provided on the front of these fluorescent lamps 21 and closing one side of the box 20, and a diffusion screen 23, The whole is configured as a surface light source that irradiates light to a relatively wide range.
In the center of the back surface of the box 20, the CC
A D camera 15 is arranged, and the CC of the optical filter 22 and the diffusion screen
Holes 22a, 2 through which lens 15a of D camera 15 is inserted
3a are respectively formed.

On the other hand, the above-mentioned optical filter 22
In order to convert the light irradiated by 1 into light-dark light that changes from light to dark, the light transmittance is configured to be different depending on the transmission place. That is, in the present embodiment, as shown by, for example, arrows X and Y, the transmittance is set so that the luminous intensity gradually increases from dark to bright from the center where the CCD camera 15 is disposed toward the periphery. Has been
As a result, as shown in FIG. 3, bright and dark light whose luminous intensity changes from dark to bright at a predetermined brightness gradient along the X or Y direction is formed, and the bright and dark light is applied to the coating surface 1 of the vehicle body 10.
0a.

The diffusing screen 23 diffuses the light transmitted through the optical filter 22 so that the coating surface 1
This is for uniformly irradiating bright and dark light to 0a.

The gradient of the light and dark light constituted by the optical filter 22 is set in advance to have a predetermined light and dark gradient in order to accurately detect a coating defect. When the shape of the film surface 10a is a curved surface, the amount of reflected light changes depending on the magnitude of the curvature, and the light-dark gradient in the received light image obtained by the CCD camera 15 changes significantly.
Therefore, brightness gradient in the received-light image is such that a predetermined slope without lowering the detection accuracy of the paint defects, the coated surface in accordance with the magnitude of the curvature of the curved surface shape and has been coated surface 10a Optical filters 22 having different transmittances capable of forming light-dark light having a light-dark gradient corresponding to the curvature of the coating film surface 10a are used so as to change the gradient of light-dark light applied to the light-receiving surface 10a. I have.

[0020] In the surface state detecting device 11 configured as described above, the defect inspection work with for painted vehicle body 10 is conveyed to the coating station S is started becomes Rukoto. That is, the robot device 13 is controlled by the robot controller 18 to keep the light irradiating means 14 and the CCD camera 15 at a constant interval, and secure them at an appropriate distance to the coating film surface 10a. Then, it is moved along the coating surface 10a. At that time, the light irradiating means 14 causes the center portion of the camera 15 to have a relatively wide coating surface 10a covering the field of view F, as shown in FIG. Light and dark light 14a, whose luminous intensity gradually increases from dark to bright, is emitted toward the periphery. For this reason, a light irradiation area having a change in brightness from dark to light is formed on the coating film surface 10a, and the C light receiving area that receives reflected light from the light irradiation area is formed.
As shown in FIG. 5, the CD camera 15
A bright and dark light-receiving image 24 that changes concentrically from dark to bright in the direction corresponding to the direction of change from dark to bright in 4a is created.

FIG. 5 shows that the lighter the line density, the higher the brightness, and the denser the line, the lower the brightness.

Therefore, when there is a defect in the irradiation area of the coating film surface 10a of the vehicle body 10, the brightness of the defect portion changes according to the shape of the defect due to the bright and dark light 14a from the one-change area corresponding to the defect. For example, in the case of a convex defect A as shown in FIG. 4, due to the convex mirror action of the convex defect A, as shown in FIG.
Is recognized as a convex defect part a having a light-dark gradient change in which a light part a2 is adjacent to the other side part. In the case of a concave defect A 'as shown in FIG. Due to the concave mirror action of A ', as shown in FIG. 5, in the received light image 24, a concave defect portion having a light-dark gradient change in which a bright portion a1' is adjacent to the image center portion side and a dark portion a2 'is adjacent to the other side portion. a 'will be recognized.

The CCD camera 15 outputs a video signal which changes in accordance with the change in the brightness of the received light image 24 to the image processor 19, and based on the video signal, the image processor 19 The coordinates, shape and size of the position are detected and stored in a memory in the host computer 17.

Next, the operation of the image processor 19 for detecting a coating defect will be described in more detail with reference to the flowchart shown in FIG. 6. First, in step S1, the light receiving image 24 created by the CCD camera 15 is captured. In step S2, the video signal is differentiated by scanning the received light image 24, for example, in the direction of the arrow x shown in FIG. In this case, if there is a paint defect, the level of the video signal changes, and the presence or absence of the defect and the size of the defect are detected by comparing the degree of the change with a preset threshold. Next, in step S3, the paint defect detected in step S2 is numbered according to the position coordinates. Then, in step S4, the positions of the bright and dark portions of each paint defect with respect to the center of the received light image 24 are calculated based on the differential signal of each paint defect. In step S5, each paint defect is calculated based on the result of step S4. The shape of the defect, i.e., whether the individual coating defect is a convex defect or a concave defect, is identified. Then, in step S6,
The data obtained in steps S2, S3 and S6 is output to the host computer 17 and stored in a memory in the host computer 17. When repairing a paint defect, the contents stored in the memory are taken out, and a predetermined repair operation corresponding to the type of the defect is performed.

[0025] When above-described coating defect detection, brightness increasing luminosity gradually coaxially to dark to light towards the periphery of the center portion more CCD camera 15 is disposed in the light irradiation means 14 as a surface light source Since the light 14a is irradiated, a dark portion is formed at the center of the irradiation area on the coating film surface 10a irradiated with the light and dark light 14a, and the light irradiating means 15 as a surface light source corresponding to the dark portion is formed. CC in the center
Since the D camera 15 is arranged, self-imaging of the camera 15 is prevented. Then, when there is a coating defect in the light-dark light 14a irradiation area on the coating film surface 10a, the reflection state of the light-dark light 14a at that part changes, and this state is located at the center of the light irradiation means 15. It will be captured by the CCD camera 15 arranged. Accordingly, it is possible to inspect the coating defect over the entire irradiation area on the coating film surface 10a, and the inspection accuracy and the inspection efficiency are improved.

Further, since the self-imaging of the CCD camera 15 arranged at the center of the light irradiating means 15 as a surface light source is prevented, the coating surface 10a is used to prevent the CCD camera 15 from self-imaging. 4, the camera 15 can be arranged in parallel with the coating film surface 10a at a predetermined interval as shown in FIG. The alignment can be performed easily and extremely accurately, and the distortion of the received light image 24 is reliably prevented, so that the received light image 24 becomes clearer and the detection accuracy of the surface state is further improved. Become.

In particular, CC at the center of the light irradiation means 15
Since the D camera 15 is arranged and both are integrated, the entire surface state detecting device 11 can be configured more compactly.

In the present embodiment, the video signal from the CCD camera 15 is analyzed by the image processor 19 to obtain a coating defect A on the coating surface 10a.
Although the case where A ′ is detected has been described, for example, by visually observing a change in the light-dark gradient in the light- receiving image 24 created by the CCD camera 15 shown in FIG.
Needless to say, it is possible to detect the coating defects A and A '.

FIG. 7 shows another embodiment of the light irradiating means as the above-mentioned surface light source. In this embodiment, the light irradiating means 34 has a plurality of light emitting diodes 41a as light sources on the front surface of a box 40. .. 41a have matrix light sources 41 as surface light sources arranged in rows and columns at predetermined intervals in the X and Y directions, and a CCD camera 35 is disposed in the center of the back surface of the box 40; Is provided with a diffusion screen 43 provided with a hole 43a through which the lens 35a of the CCD camera 35 is inserted. The light emitting diodes 41a are each capable of adjusting the luminous intensity. In the example, as in the case of the first embodiment, CC
The matrix light source 41 in which the D camera 35 is arranged is configured to emit bright and dark light whose luminous intensity gradually increases from dark to bright from the center to the periphery of the matrix light source 41. According to this, the luminous intensity of the light irradiating means 35 as a surface light source can be appropriately variably controlled according to the shape of a coating surface (not shown) or the like as a surface to be inspected. The versatility will be improved.

[0030]

As is evident from the foregoing description, according to the first invention, the inspection light of the surface light source is the luminous intensity coaxially to the dark to light towards the periphery than the center portion disposed camera of said surface light source gradually The dark area is formed at the center of the irradiation area on the surface to be inspected irradiated with the bright and dark light, and the camera is arranged at the center of the surface light source corresponding to the dark area. The self-reflection of the camera is prevented, so that the surface condition can be inspected over the entire irradiation area on the surface to be inspected irradiated by the surface light source, thereby improving the inspection accuracy and the inspection efficiency. Will do.

Further, since the self-imaging of the camera disposed at the center of the surface light source is prevented, it is necessary to arrange the camera at an angle to the surface to be inspected in order to prevent the self-imaging. without this arrangement, the pin preparative <br/> alignment of the camera is obtained performed easily and very accurately, so that the distortion of the received-light image can be reliably prevented, it is assumed photodetection image is clearer, The detection accuracy of the surface state is further improved.

Furthermore, since the camera is arranged at the center of the surface light source and the two are integrated, the entire detection device can be configured more compactly.

In particular, according to the second aspect of the present invention, image processing for detecting a concave defect or a convex defect on a surface to be inspected by identifying a portion in a received light image created by the camera whose brightness is significantly different from the surroundings. since means are provided, light in the light receiving image
The inspection accuracy is further improved as compared with the case where the surface state is inspected by visually identifying the change in the dark gradient .

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a surface state detection device according to the present invention.

FIG. 2 is an exploded perspective view of a light irradiation unit.

FIG. 3 is a graph showing a change in brightness of bright and dark light.

FIG. 4 is an enlarged view showing an irradiation state and a light receiving state.

FIG. 5 is a partially enlarged view of a received light image.

FIG. 6 is a flowchart showing a defect detection operation by the image processing processor.

FIG. 7 is a perspective view of a light irradiation unit according to another embodiment.

FIG. 8 is a schematic configuration diagram illustrating an arrangement state of cameras in a conventional surface state detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vehicle body 10a Coating surface 11 Surface condition detection device 14, 34 Light irradiation means 14a Bright and dark light 15, 35 CCD camera 17 Host computer 19 Image processor 24 Light reception image A, A 'Coating defect

Claims (2)

(57) [Claims] 1. An inspection surface has a predetermined brightness gradient in advance.
Irradiating the light urchin set, the capture reflected light from the inspected surface to create a light image, the concave defect of the inspection surface based on brightness gradient <br/> change in the light receiving image, convex defects a surface state detecting device for detecting, the a surface light source which irradiates an inspection light to the inspection surface, said to be arranged in the center of said surface light source captures reflected light from the inspected surface inspection A camera that creates a bright and dark light-receiving image according to the surface condition of the surface, and the inspection light of the surface light source changes from dark to bright toward the periphery from the center of the surface light source where the camera is arranged. A surface state detecting device, wherein the luminous intensity is set so as to increase gradually concentrically. 2. The inspection surface has a predetermined brightness gradient in advance.
Irradiating the light urchin set, the capture reflected light from the inspected surface to create a light image, the concave defect of the inspection surface based on brightness gradient <br/> change in the light receiving image, convex defects a surface state detecting device for detecting, the a surface light source which irradiates an inspection light to the inspection surface, said to be arranged in the center of said surface light source captures reflected light from the inspected surface inspection a camera for creating the brightness is received-light image in accordance with the surface state of the surface, by the brightness in the received-light image created by the camera to identify the significantly different points from the surrounding, concave of the surface to be inspected
Image processing means for detecting the indentation and the convex defect, and the inspection light of the surface light source is concentrically luminous from dark to bright from the center of the surface light source where the camera is arranged. The surface condition detecting device is set so that is gradually increased.