JPH1010054A - Surface defect inspection equipment - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To use no paint for marking on the surface to be inspected.
To provide a surface defect inspection device capable of notifying a defect occurrence position. SOLUTION: An illuminating means 100 for forming a predetermined light and dark pattern on the surface of an inspection object 102, an imaging means 101 for converting a received image obtained by imaging the inspection surface into electric signal image data, and the image Defect detection means 103 for performing a predetermined process on the data to detect a defect, operation control means 104 for calculating the position of the detected defect on the surface to be inspected, and based on the calculated defect occurrence position information Projection means 105 for projecting light near the defect occurrence position on the inspection surface is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting a surface defect of an object to be inspected, for example, a surface defect such as unevenness of a painted surface of an automobile body.

[0002]

2. Description of the Related Art A conventional surface defect inspection apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-235623. In the coating defect inspection apparatus that detects a defect on a painted surface by processing an image signal obtained by imaging a surface to be inspected, a mark is directly added to a position where the detected defect is generated.

[0003]

However, the conventional surface defect inspection apparatus as described above has the following problems. For example, when a marking device such as ink is used to mark a defect occurrence position with a marking device, there are many troubles such as clogging of the coating material in the marking device, and there is a problem that the defect flows out to a subsequent process. Further, when the marking device malfunctions, the surface to be inspected is stained with the paint for the mark, and there is a problem that extra work such as cleaning occurs. The present invention has been made to solve the problems of the prior art as described above, and it is an object of the present invention to provide a surface defect inspection apparatus capable of notifying a defect occurrence position without using a paint for a mark on a surface to be inspected. Aim.

[0004]

Means for Solving the Problems In order to achieve the above object, the present invention is configured as described in the claims. FIG. 1 corresponds to the first aspect of the present invention. In FIG. 1, reference numeral 102 denotes an inspection object, for example, a painted surface of an automobile body. Also, 100
Reference numeral denotes illumination means for projecting a predetermined light-dark pattern on the surface to be inspected. Reference numeral 101 denotes an imaging unit that captures an image of the surface to be inspected and converts the light / dark pattern into image data of an electric signal, such as a video camera such as a CCD camera. Reference numeral 103 denotes a defect detection unit that processes image data obtained by the imaging unit 101 to detect a defect.
Numeral 104 denotes arithmetic control means for calculating the position of the detected defect on the surface to be inspected. These 10
The portions 3 and 104 are constituted by, for example, a computer. Reference numeral 105 denotes a projection unit that projects light near the defect occurrence position on the inspection surface based on the calculated defect occurrence position information. The portion 105 is composed of, for example, a projector light source. The above configuration is described in, for example, FIG.
7 corresponds to the embodiment described with reference to FIG. Further, as described in claim 2, the projection means 105 changes the light projection direction based on the movement amount and the movement direction of the inspected object 102. The above configuration corresponds to, for example, an embodiment described later with reference to FIG. Further, as described in claim 3, the projection means 105 changes the color, shape or size of the projection light according to the size of the detected defect. The above configuration corresponds to, for example, an embodiment described later with reference to FIG. According to a fourth aspect of the present invention, the projection means 105 changes the color, shape or size of the projection light according to the type of the detected defect. The above configuration corresponds to, for example, an embodiment described later with reference to FIG. Also, as described in claim 5,
The projection unit 105 changes the color of the projection light based on a physical quantity related to the color of the surface to be inspected.

[0005]

As described above, in the invention according to the first aspect, a predetermined light-dark pattern is projected on the surface to be inspected by the illuminating means, which is imaged by the imaging means, and the light-dark pattern is converted into an electric signal image pattern. Convert. Next, the defect detecting means extracts a luminance change occurring in the uneven defect portion by image processing such as differentiation. Next, the arithmetic control means calculates the defect occurrence position detected by the defect detection means, and operates so as to project predetermined light near the defect occurrence position of the inspected object using the projection means. As described above, in order to inspect the entire inspected surface in the first aspect of the present invention, the inspected object or the illumination means and the projection means are sequentially moved so that the field of view of the camera scans the entire inspected surface. Configure. Next, a second aspect is that the projection means moves the light projection direction in accordance with the movement of the object to be inspected, so that the defect occurrence position can be recognized even when the object to be inspected is moved. Next, according to the third aspect, the size of the defect can be determined based on the color, shape or size of the projection light. According to the fourth aspect, the type of the defect can be determined based on the color, shape or size of the projection light. Further, since the color of the projection light changes according to the color of the surface to be inspected, it is easy to find a defect regardless of the color of the surface to be inspected.

[0006]

Hereinafter, the present invention will be described with reference to the drawings. FIG. 2 is a diagram showing the first embodiment of the present invention, in which a defect inspection of a painted surface of an automobile is taken as an example, and is a schematic top view of the present inspection device. In FIG. 2, reference numeral 1 denotes a lighting device, which has an arch (gate) shape surrounding the body 3 (see FIG. 3). The illumination device 1 is configured to project a predetermined light-dark pattern on the surface to be inspected. Reference numeral 2 denotes a video camera, which is attached to a predetermined position and a number of camera stands having substantially the same shape as that of the illumination device 1, and captures an image of the surface to be inspected on which the light / dark pattern is reflected. Reference numeral 4 denotes a defect detection device that executes a predetermined process. Reference numeral 5 denotes an arithmetic and control unit, which is like a host computer that calculates a defect occurrence position, controls the projector 6, and the like.

FIG. 3 is a schematic view of the body 3 as viewed from the front. As shown in the figure, the field of view of each of the video cameras 2 is attached to the camera stand so as to cover the surface of the body 3 without any gap and form a continuous band along the cross-sectional contour of the body 3. The body 3 is placed on a carriage or the like and moves on the rails in the illumination device 1 and the camera stand by a conveyor, at which point the predetermined processing is performed by the defect detection device 4, and the surface is inspected. An inspection of a painted surface of a certain body 3 is performed. Next, an example of a defect detection procedure in the defect detection device 4 will be described with reference to FIG. When the arithmetic and control unit 5 detects that the body 3 has entered the field of view of the camera using a known technique such as a photoelectric tube (not shown), the arithmetic and control unit 5 sends a signal for starting the processing to the defect detection unit 4 and outputs the defect. The detection device 4 starts a predetermined process. First, when the image of the video camera 2 is captured (step S
1), in the original image (step S1) shown in FIG. 5A, light is irregularly reflected at the uneven defect 7, so that it appears as a dark portion in a bright pattern as shown in the figure. When an edge detection process such as differentiation (Step S2) is performed on the original image (Step S1) and binarized by a predetermined threshold value in Step S3, there is a luminance change as shown in FIG. A binary image is obtained in which the region, that is, the region with a high spatial frequency, is white and the other portions are black. Labeling (= numbering) is performed on white pixels of the binary image (step S3) in step S4, and area / centroid calculation is performed in step S5. In the white pixels of the binary image (step S3), the defect 7 is an isolated point, and the boundary of the light and dark pattern is a large object that crosses the top and bottom of the screen. When only small isolated points are extracted (step S6), an image as shown in FIG. 5C is obtained, and the defect 7 can be detected. The defect detection data (area information and barycentric coordinate information of the defect 7 in the image) is sent to the arithmetic and control unit 5 for each process described above. Note that the above-described defect detection method is not limited to the present embodiment.

Next, an example of various processes in the arithmetic and control unit 5 will be described with reference to FIG. After detecting the body 3, the arithmetic and control unit 5 calculates and finds the current body position, that is, which position of the body 3 is projected by the belt-like camera field of view. This can be easily calculated from the rotation information of the conveyor or the like. Next, the defect data from the defect detection device 4 is read. Therefore, it is possible to obtain the position of the defect 7 detected at an arbitrary point on the body surface, that is, the position where the defect 7 occurs in the body transport direction and the body cross-sectional direction. Next, the projection position of the defect 7 in the projector 6 described later is calculated. The above-described series of processing is continuously performed until the body 3 passes. Next, body 3
When the camera has passed through the field of view of the video camera 2, the inspected 1
A control signal such as defect projection position information of the body 3 is output to the projector 6. The body position calculation, the defect occurrence position calculation method, and the like are not limited to the present embodiment.

Next, an example of the projection means in the projector 6 will be described with reference to FIG. When the inspection for one body is completed in the above procedure, the projector 6 as shown in FIG. 7 projects the projection light 8 directly near the defect 7 on the body surface according to a signal from the arithmetic and control unit 5. I do. The projection direction of the projection light 8 is determined by the projector 6 and the body 3
If the relative positional relationship with 1 is known in advance, it can be calculated. In the first embodiment, the body 31 and the projector 6 are stationary, and the projector 6 performs a work of correcting the defect 7 while projecting the defect position. Further, as shown in FIG. 7, the projector 6 projects the image to the immediately preceding body 31, and the next body 32 only needs to have a positional relationship just before entering the visual field of the video camera 2 (dotted line in the figure). Further, the projection of defect positions on the hood and the roof surface is performed by another projector (not shown).

Next, a description will be given of a change in the light projection direction of the projector 6 as the projecting means according to a second embodiment of the present invention. In the first embodiment, the body 3 is stationary during light projection by the projector 6, but in the second embodiment, the defect position is projected without stopping the body 3. For example, FIG.
When the body 3 is conveyed in the direction of the arrow as shown in the figure, if the projection direction of the projection light 8 follows the movement of the body 3, the next operation can be performed without stopping the conveyor. Can be. The amount of change in the light projection direction can be calculated if the relative positional relationship between the projector 6 and the body 3 and the body conveyance speed are known in advance.
As another embodiment, a configuration in which the projector 6 moves together with the transport of the body 3 while the defect position projection is required can also mark the defect occurrence position without stopping the conveyor. .

Next, a description will be given of a projection method by the projector 6 as a projection unit according to a third embodiment of the present invention. In the third embodiment, the projection light is changed according to the size (size) of the detected defect. For example, the relationship between the area S of the defect 7 obtained by the defect detection device 4 and the result of the sensory evaluation of the defect size by the operator is measured in advance, the defect size is classified according to the area S, and the projection is performed according to the rank. Change the light. For example, as shown in FIG. 9, the size of the projection light is changed (a) or the shape is changed (b) according to the rank of the defect. When the color of the projection light 8 is changed or the ranks are represented by A, B, and C, light in the form of letters A, B, and C may be projected.

Next, a description will be given of a projection method by a projector 6 as a projection means according to a fourth embodiment of the present invention. In the fourth embodiment,
The projection light 8 is changed according to the type of the detected defect 7. For example, the size, shape, color, and the like of the projection light 8 are changed according to the type of the defect 7 such as a point-like defect or a thin defect such as a flaw, as in the third embodiment. The determination of the type of the defect 7 in the fourth embodiment can be realized by calculating the peripheral length, the fillet diameter, and the like in addition to the defect area S described above in the defect detection device 4.

Next, a description will be given of a projection method of the projector 6 as a projection means according to a fifth embodiment of the present invention. In the fifth embodiment, the color of the projection light 8 is changed according to the color of the surface to be inspected, for example, the paint color of the body 3. For example, even if white light is applied to a light-colored painted surface such as white or silver metallic, it is difficult to visually confirm the contrast because of low contrast. In the fifth embodiment, for example, the projection light 8 of a conspicuous color such as red light for a light color system and white light for a dark color system is used. Can be facilitated.

[0014]

As described above, according to the present invention, it is possible to obtain the effect that the defect occurrence position on the surface to be inspected is reliably specified and the workability in the post-process is improved.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of the present invention.

FIG. 2 is a schematic plan view of the first embodiment.

FIG. 3 is a schematic front view of the first embodiment.

FIG. 4 is a flowchart illustrating an example of a defect detection procedure.

FIG. 5 is a diagram illustrating an example of image processing for defect detection.

FIG. 6 is a flowchart illustrating an example of a processing procedure in an arithmetic control unit.

FIG. 7 is a schematic plan view of the first embodiment.

FIG. 8 is a schematic side view of the second embodiment.

FIG. 9 is an explanatory diagram showing a projection light pattern according to the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Illumination device 2 Video camera 3 Body 4 Defect detection device 5 Arithmetic control device 6 Projector 7 Defect 8 Projection light 31 Body 32 Body 100 Illumination means 101 Imaging means 102 Object to be inspected (image) 103 Defect detection means 104 Operation control means 105 Projection means

Claims (5)

[Claims] 1. A surface defect inspection apparatus that irradiates a surface to be inspected with light, creates a light reception image based on light reflected from the surface to be inspected, and detects a defect on the surface to be inspected based on the light reception image. An illumination unit that forms a predetermined light and dark pattern on the surface of the inspection object; an imaging unit that converts a received light image obtained by imaging the inspection surface into image data of an electric signal; Detecting means for detecting a defect by performing the processing described above; calculating control means for calculating a position where the detected defect occurs on the surface to be inspected; and generating a defect on the surface to be inspected based on the calculated defect occurrence position information. A surface defect inspection apparatus, comprising: projection means for projecting light near a position. 2. The surface defect inspection apparatus according to claim 1, wherein said projection means changes a light projection direction based on a moving amount and a moving direction of the inspection object. 3. The surface defect inspection apparatus according to claim 1, wherein the projection unit changes the color, shape, or size of the projection light according to the size of the detected defect. 4. The surface defect inspection apparatus according to claim 1, wherein the projection unit changes the color, shape, or size of the projection light according to the type of the detected defect. 5. The surface defect inspection apparatus according to claim 1, wherein the projection unit changes the color of the projection light based on a physical quantity related to the color of the surface to be inspected.