JP2011149814A - Coating inspection device and coating inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect surely a coating failure in coating performed on a workpiece or the like to be used for a vehicle body, by using an apparatus having a simple constitution. <P>SOLUTION: A plurality of light sources 203 are arranged so as to enclose around the axis, the optical axis AX of a camera 202 for imaging the surface of a workpiece WK. The light sources 203 are lit one by one successively by control of a control circuit chip 204, to irradiate the surface of the workpiece WK with light from various directions. The camera 202 images the surface of the workpiece WK at every time when the light sources 203 are lit one by one successively. An image processing device 104 receives image data transmitted from the camera 202, performs image processing, and outputs a processing result to a monitor 105. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coating inspection apparatus and a coating inspection method for determining whether a coating is good or bad.

  When a workpiece or the like that becomes a vehicle body is painted, irregularities may be generated on the surface of the workpiece due to dust, dirt, or irregularities. In order to find such a defective portion, the worker has conventionally checked the surface of the workpiece on which the coating has been performed. Further, as another discovery method, it is conceivable to detect a coating defect using a coating inspection apparatus described in Patent Document 1 or a coating surface inspection apparatus described in Patent Document 2.

  The coating inspection apparatus 8 described in Patent Document 1 includes a detection unit 9 and an image processing unit 10, and makes the minute scratches generated by polishing the painted surface F easy to visually recognize. It is a device that inspects the presence or absence of painting defects by groups. The detection unit 9 can be moved by an operator or a work robot, and illuminating means 11 irradiates the inspection part of the painted surface F with light on the box-shaped frame 17 that opens toward the inspection part Fa. In addition, each part such as the imaging unit 12 that receives the reflected light is integrally provided. Of the light irradiated to the inspection site of the painted surface F, the light that hits a group of minute flaws on the surface of the inspection site Fa becomes scattered light. The image processing unit 10 captures reflected light (scattered light) imaged by the detection unit 9 as an image, and displays and outputs an image obtained by performing image processing on the image so that a minute wound group on the surface of the examination site Fa can be easily seen. Then, the quality of the coating of the examination site Fa is determined based on the displayed and output image. Patent Document 1 describes that the illumination unit 11 is arranged so that the light source is symmetrically disposed via the imaging unit 12 and the examination site Fa is illuminated from both sides with the imaging unit 12 interposed therebetween.

  The coating surface inspection apparatus described in Patent Document 2 includes a surface light source 10 and an imaging device on a base 29 attached to the distal ends of robot arms 9 and 9a of robots 39 and 39a disposed on both sides of a conveyance path of a vehicle 1. 20 is attached and comprised. The robots 39 and 39a scan the coating surface so as to sequentially shift the imaging device 20, and can arbitrarily control the three-dimensional position facing the coating surface and the angle in the three axial directions at each scanning position. . The surface light source 10 includes a light source 11 composed of a light emitting diode group in which a plurality of light emitting diodes 11a arranged in an arc shape are further arranged in the depth direction on a base surface 12, and a light source from the light emitting diode 11a with the arc center point as a focal point F. A Fresnel lens 15 that deflects light in parallel, a slit plate 17 that forms a vertically long slit 16 at the position of the focal point F, and a case 13 are configured. In Patent Document 2, a surface light source 10 emits parallel light or substantially parallel light to irradiate a coating surface to be inspected, and an imaging device 20 captures reflected light on the coating surface to be inspected by an imaging device 20 (avalanche multiplication type solid-state imaging). The image is picked up by the camera 21) and an analog image signal in the image pickup range is supplied to the image processing device 30, and a minute defect on the coating surface to be inspected is detected with high sensitivity and high resolution by the reflected light. Are listed.

JP 2007-93340 A (paragraphs 0028-0033, 0036 and FIG. 5) JP 2006-38550 A (paragraphs 0013, 0018 to 0020, FIGS. 1, 4 and 5)

  The inventor applies illumination light to a workpiece that has been painted in order to realize automation of the painting inspection work that checks for coating defects that occur on the surface of the workpiece, and the workpiece in a state in which this illumination light has been applied. The image was picked up by a camera and converted into image data, and the image data was subjected to data processing to extract a portion corresponding to a shadow portion. However, in the apparatus in which the positional relationship between the imaging means (imaging apparatus) and the illumination means (surface light source) is fixed, such as the coating inspection apparatus described in Patent Document 1 and the coating surface inspection apparatus described in Patent Document 2, I noticed that shadows may not occur even if there are poorly painted parts, depending on the shape of the unevenness on the surface of the workpiece.

  The present invention has been made in view of the above points, and an object of the present invention is to reliably detect a coating failure using a device having a simple configuration.

  The coating inspection apparatus of the present invention includes an imaging unit that captures an image of a painted surface, a plurality of light sources that are arranged so as to surround the optical axis of the imaging unit, and irradiate light on the painted surface, and the light source. A control unit that sequentially lights up one by one and causes the imaging unit to capture images each time, and an image processing unit that receives a signal from the imaging unit and performs image processing to output the processing result.

  In the coating inspection method of the present invention, a plurality of light sources arranged so as to surround an optical axis of an imaging unit that captures an image of a painted surface are sequentially turned on one by one to irradiate the painted surface with light. Each time the light sources are sequentially turned on one by one, the imaging unit images the painted surface, and the image processing unit receives a signal from the imaging unit and performs image processing. Outputting a result.

  According to the present invention, since a plurality of light sources are sequentially turned on one by one and shadows due to poor coating on the painted surface are likely to occur, it is possible to reliably detect poor coating using a device with a simple configuration. it can.

It is a block diagram of a coating inspection apparatus. It is the figure which looked at the coating inspection unit from the opening side. It is sectional drawing of the coating inspection unit which is inspecting the surface of a work. It is a flowchart which shows the flow of the process which a control circuit chip performs. (A)-(d) is explanatory drawing which shows the flow of the imaging of the surface of the workpiece | work in a coating inspection apparatus. (A)-(d) is explanatory drawing which shows a mode that the light from a light source hits the irregularities and the crack which arose on the surface of the workpiece | work, and a shadow appears. It is the figure which looked at the coating inspection unit of the modification from the opening side.

  One embodiment will be described with reference to FIGS. FIG. 1 is a block diagram of the coating inspection apparatus 101. The coating inspection apparatus 101 includes a robot 102, a robot control panel 103, a coating inspection unit 201, an image processing apparatus 104, and a monitor 105.

  The robots 102 are arranged on both sides of the conveyance path of the workpiece WK along a painting process line for painting the workpiece WK as an automobile body. The robot 102 has a movable arm 102a. A coating inspection unit 201 is attached to the tip of the movable arm 102a. The robot 102 includes a circuit, a mechanism, and a power source for moving in accordance with a control signal transmitted from the robot control panel 103. The robot 102 receives an electrical signal from the robot control panel 103, moves the movable arm 102a, and performs a coating inspection. The unit 201 is scanned along the surface (painted surface) of the workpiece WK. The movable arm 102a has a universal joint (not shown) so that the three-dimensional position and the angle in the three-axis direction can be arbitrarily moved with respect to the surface of the workpiece WK at each scanning position.

  The coating inspection unit 201 images the surface of the workpiece WK and transmits a data signal corresponding to the imaging result to the image processing device 104. The image processing apparatus 104 is a computer and incorporates a program for image processing the imaging result of the paint inspection unit 201 based on the data signal. The image processing device 104 outputs and displays the result of this image processing on the monitor 105. For example, a liquid crystal display can be used for the monitor 105.

  FIG. 2 is a view of the coating inspection unit 201 as viewed from the opening side. FIG. 3 is a cross-sectional view of the coating inspection unit 201 inspecting the surface of the workpiece WK. The coating inspection unit 201 will be described in detail with reference to FIGS. The coating inspection unit 201 includes a camera 202 as an imaging unit, a plurality of light sources 203, and a control circuit chip 204 as a control unit. The camera 202 and the light source 203 are housed in a flat rectangular parallelepiped frame 205 having one surface opened. A movable arm 102a is attached to the center of the bottom 205a of the frame 205 facing the opening of the frame 205. A control circuit chip 204 is disposed on the surface of the bottom 205a on the side where the movable arm 102a extends. The control circuit chip 204 is connected to each of the camera 202 and the plurality of light sources 203 via a cord (not shown), and a circuit for driving and controlling them is incorporated.

  The camera 202 is disposed through the center of the bottom portion 205a of the frame 205, and is disposed in a direction in which the outside of the frame 205 is imaged. At this time, the optical axis AX of the camera 202 is directed parallel to the direction in which the side portion 205b of the frame 205 extends.

  The plurality of light sources 203 emit visible light, are attached to each of the side portions 205b of the frame 205 inside the space formed by the frame 205, and surround the optical axis AX of the camera 202 around the axis.

  FIG. 4 is a flowchart showing a flow of processing performed by the control circuit chip 204. The control circuit chip 204 sequentially turns on the light sources 203 one by one, causes the camera 202 to capture images each time, generates image data based on the imaging results, and performs processing to transmit and output the image data to the image processing device 104. .

  More specifically, the control circuit chip 204 waits for input of an imaging start signal from the image processing device 104 (step S101). The image processing apparatus 104 sends a control signal to the robot control panel 103 to move the robot 102, position the coating inspection unit 201 in advance on the surface of the workpiece WK where the coating inspection is to be performed, and then the image processing apparatus 104. The imaging start signal is transmitted and output.

  When the imaging start signal is input (Y in step S101), the control circuit chip 204 turns on only one light source 203 among the plurality of light sources 203 (step S102). Thereby, the surface of the workpiece WK is irradiated with the light from the light source 203 that has been turned on.

  Subsequently, the control circuit chip 204 controls the camera 202 to image the surface of the work WK (step S103). The camera 202 includes a lens and a light receiving element (both not shown), generates image data based on light incident on the light receiving element through the lens, and transmits this image data to the control circuit chip 204. The control circuit chip 204 transmits and outputs the image data input from the camera 202 to the image processing device 104 (step S104).

  Subsequently, when the light source 203 that has not been lit remains (Y in Step S105), the control circuit chip 204 turns off the light source 203 that is currently lit and then turns on another light source that has not been lit. Only 203 is turned on (step S106), and the process returns to step S103. Thereby, the surface of the workpiece WK is irradiated with light from the light source 203 incident at an angle different from that in step S102.

  On the other hand, when all the light sources 203 are turned on and imaging by the camera 202 is performed (N in step S106), the control circuit chip 204 turns off the currently lit light source 203 (step S107), and the image processing device 104 is turned on. An imaging completion signal is transmitted and output (step S108), and a series of processing is completed. The image processing apparatus 104 that has received the imaging completion signal sends a control signal to the robot control panel 103 to move the robot 102, and a part different from the part where the coating inspection is performed in the above-described series of processes on the surface of the work WK. Then, the coating inspection unit 201 is positioned, and the imaging start signal is transmitted again to the image processing apparatus 104.

  Refer to FIG. 1 again. When the image processing apparatus 104 receives the image data transmitted from the control circuit chip 204, the image processing apparatus 104 performs image processing according to the description of the program incorporated in the image processing apparatus 104, and outputs and displays the result of the image processing on the monitor 105. . In this image processing, the presence / absence of a shadow included in a coating inspection target portion on the surface of the work WK imaged by the camera 202 is determined based on image data from the coating inspection unit 201 (control circuit chip 204). An example of the image processing includes captured image data for each vehicle type of the painted workpiece WK stored in advance in an image database (not shown) in association with the position and orientation information of the movable arm 102a, and a coating inspection unit. This is a process of comparing the pixels with the image data from 201 (control circuit chip 204) and determining that there is a coating failure when the number of pixels in the mismatched area is a predetermined number or more. Another example of the image processing is a process of determining the luminance in the image data from the coating inspection unit 201 (control circuit chip 204) as a numerical value for each pixel and determining that the coating is defective when the luminance is a predetermined value or less. Various other types of image processing can be used.

  FIG. 5A to FIG. 5D are explanatory views showing the flow of imaging the surface of the workpiece WK in the coating inspection apparatus 101. Hereinafter, the four light sources 203 included in the coating inspection unit 201 are referred to as a first light source 203a, a second light source 203b, a third light source 203c, and a fourth light source 203d in the clockwise order in FIGS. 5 (a) to 5 (d). Call. 5A to 5D show the coating inspection apparatus 101 when the camera 202 looks at the surface of the workpiece WK.

  In the coating inspection apparatus 101, a plurality of light sources 203 (first light source 203 a to fourth light source 203 d) are sequentially turned on one by one under the control performed by the control circuit chip 204. An example of the turn-on order is the first light source 203a (FIG. 5A), the second light source 203b (FIG. 5B), the third light source 203c (FIG. 5C), and the fourth light source 203d (FIG. 5). (D)). In this way, when the plurality of light sources 203 arranged so as to surround the optical axis AX (see FIG. 3) of the camera 202 are turned on one by one, the surface of the workpiece WK receives light from various directions. It will be incident. Each time the light source 203 is turned on one by one, the camera 202 images the surface of the work WK, and the image data generated by the imaging is processed by the image processing device 104 and output to the monitor 105.

  FIG. 6A to FIG. 6D are explanatory views showing a state in which a shadow 303 appears when the light from the light source 203 strikes the bumps 301 and the scratch 302 generated on the surface of the workpiece WK. When light is incident on the surface of the work WK, a shadow 303 is generated at a portion where the coating is poor due to the bumps 301 and the scratch 302 generated on the surface of the work WK. Here, what is important in the coating inspection apparatus 101 according to the present embodiment is that the light 301 is incident on the surface of the work WK from various directions as described above, so that the shapes of the bumps 301 and the scratches 302 are determined. Even if it is not present, the shadow 303 is surely generated, the shadow 303 is captured by the camera 202, and the result is displayed on the monitor 105.

  As described above, according to the coating inspection apparatus 101 of the present embodiment, the plurality of light sources 203 are sequentially turned on one by one and the workpiece WK is provided with a simple device configuration including the camera 202 and the plurality of light sources 203. Since the shadows 303 due to poor coating such as bumps 301 and scratches 302 generated on the surface of the workpiece W are easily generated, it is possible to reliably detect the defective coating in the painting process of the workpiece WK. In the coating inspection apparatus 101, since the shadow 303 is surely generated, it is not necessary to provide a mechanism for rotating the coating inspection unit 201 with respect to the surface of the workpiece WK in order to change the direction of light. The configuration of the inspection apparatus 101 can be simplified.

  FIG. 7 is a view of a coating inspection unit 201 ′ according to a modification as viewed from the opening side. The plurality of light sources 203 may be arranged so as to surround the optical axis AX of the camera 202 around the axis. For this reason, the number of the light sources 203 may not be four. As an example, as shown in FIG. 7, eight light sources 203 may be attached to the coating inspection unit 201 ′ so as to form an octagon.

101 Coating inspection device 104 Image processing device (image processing unit)
202 Camera (imaging part)
203 Light source 204 Control circuit chip (control unit)
AX Optical axis WK Workpiece (painted surface)

Claims (2)

An imaging unit for imaging the painted surface;
A plurality of light sources arranged so as to surround the optical axis of the imaging unit around the axis, and irradiating the coating surface with light;
A control unit that sequentially turns on the light sources one by one and causes the imaging unit to capture images each time;
An image processing unit that receives a signal from the imaging unit, performs image processing, and outputs a processing result;
A coating inspection device. A plurality of light sources arranged so as to surround the optical axis of the imaging unit that images the painted surface around the axis, sequentially lighting one by one and irradiating the painted surface with light,
Each time the light sources are sequentially turned on one by one, the imaging unit images the painted surface;
The image processing unit receives a signal from the imaging unit, performs image processing, and outputs a processing result;
A coating inspection method comprising:

Images